MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'Current Topics in Developmental Biology' source. Mon, 09 Nov 2009 16:20:03 +0100 http://www.medworm.com/index.php?rid=2782432&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19737639%26dopt%3DAbstract Authors: Lecuit T PMID: 19737639 [PubMed - in process] (Source: Current Topics in Developmental Biology) Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2782432 Thu, 10 Sep 2009 19:48:02 +0100 2782432 http://www.medworm.com/index.php?rid=2782431&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19737640%26dopt%3DAbstract Authors: Borghi N, James Nelson W A major challenge in developmental biology is to understand how cellular processes that result from expression of the genetic program determine the material properties and shape transformations of tissues during morphogenesis. Cell/cell adhesion is critical in development, and it controls many aspects of tissue rearrangements that support morphogenesis. Intercellular adhesion not only allows cells to adhere together but also supports structure and function compartmentalization on the scale of cell assemblies, tissues, and organs. In metazoans, cadherins comprise a major class of cell/cell adhesion proteins. They form Ca(2+)-dependent, homophilic adhesive contacts between neighboring cells that results in remodeling of the underlying cortical cytoskelet... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2782431 Thu, 10 Sep 2009 19:48:02 +0100 2782431 http://www.medworm.com/index.php?rid=2782430&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19737641%26dopt%3DAbstract Authors: Nishimura T, Takeichi M Morphogenesis of epithelial tissues involves various forms of reshaping of cell layers, such as invagination or bending, convergent extension, and epithelial-mesenchymal transition. At the cellular level, these processes include changes in the shape, position, and assembly pattern of cells. During such morphogenetic processes, epithelial sheets in general maintain their multicellular architecture, implying that they must engage the mechanisms to change the spatial relationship with their neighbors without disrupting the junctions. A major junctional structure in epithelial tissues is the "adherens junction," which is composed of cadherin adhesion receptors and associated proteins including F-actin. The adherens junctions are required for the firm associ... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2782430 Thu, 10 Sep 2009 19:48:02 +0100 2782430 http://www.medworm.com/index.php?rid=2782429&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19737642%26dopt%3DAbstract Authors: Harris TJ, Sawyer JK, Peifer M One key challenge for cell and developmental biologists is to determine how the cytoskeletal toolkit is used to build embryonic tissues and organs. Here, we review recent progress in meeting this challenge, focusing on epithelial morphogenesis in the Drosophila embryo as a model. We outline how actin and microtubule networks are regulated by embryonic patterning systems, and how they affect cell shape, cell behavior, and cell-cell interactions to shape epithelial structures. We focus on the formation of the first epithelium at cellularization, the assembly of junctions, apical constriction of cells in the ventral furrow, cell intercalation in the germband, and epithelial sheet migration during dorsal closure. These events provide models for uncov... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2782429 Thu, 10 Sep 2009 19:48:02 +0100 2782429 http://www.medworm.com/index.php?rid=2782428&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19737643%26dopt%3DAbstract Authors: Gibson WT, Gibson MC Epithelia are sheets of tightly adherent cells that line both internal and external surfaces in a vast array of metazoans. During development, an intrinsic consequence of coupling tight adhesion with cellular proliferation is the emergence of an epithelial form characterized by a stereotyped distribution of polygonal cell shapes. Despite the near universality of this constraint on cell shape and tissue organization, very little is known about the possible implications of cell pattern geometry for mechanical properties of tissues or key biological processes, such as planar polarization, tissue remodeling, and cell division. In this chapter, through an examination of increasingly complex models, we highlight what is known about the role of mitotic proliferat... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2782428 Thu, 10 Sep 2009 19:48:02 +0100 2782428 http://www.medworm.com/index.php?rid=2782427&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19737644%26dopt%3DAbstract Authors: Cagan R The Drosophila eye is one of nature's most beautiful structures and one of its most useful. It has emerged as a favored model for understanding the processes that direct cell fate specification, patterning, and morphogenesis. Though composed of thousands of cells, each fly eye is a simple repeating pattern of perhaps a dozen cell types arranged in a hexagonal array that optimizes coverage of the visual field. This simple structure combined with powerful genetic tools make the fly eye an ideal model to explore the relationships between local cell fate specification and global tissue patterning. In this chapter, I discuss the basic principles that have emerged from three decades of close study. We now understand at a useful level some of the basic principles of cell fate... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2782427 Thu, 10 Sep 2009 19:48:02 +0100 2782427 http://www.medworm.com/index.php?rid=2782426&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19737645%26dopt%3DAbstract Authors: Baer MM, Chanut-Delalande H, Affolter M Biological tubes are integral components of many organs. Based on their cellular organization, tubes can be divided into three types: multicellular, unicellular, and intracellular. The mechanisms by which these tubes form during development vary significantly, in many cases even for those sharing a similar final architecture. Here, we present recent advances in studying cellular and molecular aspects of tubulogenesis in different organisms. PMID: 19737645 [PubMed - in process] (Source: Current Topics in Developmental Biology) Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2782426 Thu, 10 Sep 2009 19:48:02 +0100 2782426 http://www.medworm.com/index.php?rid=2782425&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19737646%26dopt%3DAbstract Authors: Yin C, Ciruna B, Solnica-Krezel L During vertebrate gastrulation, coordinated cell movements shape the basic body plan. Key components of gastrulation are convergence and extension (C&E) movements, which narrow and lengthen the embryonic tissues, respectively. The rates of C&E movements differ significantly according to the position and the stage of gastrulation. Here, we review the distinct cellular behaviors that define the spatial and temporal patterns of C&E movements, with the special emphasis on zebrafish. We also summarize the molecular regulation of these cellular behaviors and the interplay between different signaling pathways that drive C&E. Finally, to ensure efficient C&E movements, cells must achieve mediolaterally-elongated cell morphology and... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2782425 Thu, 10 Sep 2009 19:48:02 +0100 2782425 http://www.medworm.com/index.php?rid=2675039&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19651299%26dopt%3DAbstract Authors: PMID: 19651299 [PubMed - in process] (Source: Current Topics in Developmental Biology) Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2675039 Thu, 06 Aug 2009 20:52:03 +0100 2675039 http://www.medworm.com/index.php?rid=2675038&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19651300%26dopt%3DAbstract Authors: Maeda RK, Karch F In his 1978 seminal paper, Ed Lewis described a series of mutations that affect the segmental identities of the segments forming the posterior two-thirds of the Drosophila body plan. In each class of mutations, particular segments developed like copies of a more-anterior segment. Genetic mapping of the different classes of mutations led to the discovery that their arrangement along the chromosome paralleled the body segments they affect along the anteroposterior axis of the fly. As all these mutations mapped to the same cytological location, he named this chromosomal locus after its founding mutation. Thus the first homeotic gene (Hox) cluster became known as the bithorax complex (BX-C). Even before the sequencing of the BX-C, the fact that these similar muta... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2675038 Thu, 06 Aug 2009 20:52:03 +0100 2675038 http://www.medworm.com/index.php?rid=2675037&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19651301%26dopt%3DAbstract Authors: Gehring WJ, Kloter U, Suga H In this chapter, we consider the question of how the ordered clusters of Hox genes arose during evolution. Since ordered Hox clusters are found in all major superphyla, we have to assume that the Hox clusters arose before the Cambrian "explosion" giving rise to all of these taxa. Based on his studies of the bithorax complex (BX-C) in Drosophila Lewis considered the ground state to be the mesothoracic segment (T2) since the deletion of all of the genes of the BX-C leads to a transformation of all segments from T3 to A8/9 (the last abdominal segment) into T2 segments. We define the developmental ground state genetically, by assuming that loss-of-function mutants lead to transformations toward the ground state, whereas gain-of-function mutants lead to... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2675037 Thu, 06 Aug 2009 20:52:03 +0100 2675037 http://www.medworm.com/index.php?rid=2675036&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19651302%26dopt%3DAbstract Authors: Mann RS, Lelli KM, Joshi R Hox proteins are well known for executing highly specific functions in vivo, but our understanding of the molecular mechanisms underlying gene regulation by these fascinating proteins has lagged behind. The premise of this review is that an understanding of gene regulation-by any transcription factor-requires the dissection of the cis-regulatory elements that they act upon. With this goal in mind, we review the concepts and ideas regarding gene regulation by Hox proteins and apply them to a curated list of directly regulated Hox cis-regulatory elements that have been validated in the literature. Our analysis of the Hox-binding sites within these elements suggests several emerging generalizations. We distinguish between Hox cofactors, proteins that bi... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2675036 Thu, 06 Aug 2009 20:52:03 +0100 2675036 http://www.medworm.com/index.php?rid=2675035&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19651303%26dopt%3DAbstract Authors: Tümpel S, Wiedemann LM, Krumlauf R In the vertebrate central nervous system, the hindbrain is an important center for coordinating motor activity, posture, equilibrium, sleep patterns, and essential unconscious functions, such as breathing rhythms and blood circulation. During development, the vertebrate hindbrain depends upon the process of segmentation or compartmentalization to create and organize regional properties essential for orchestrating its highly conserved functional roles. The process of segmentation in the hindbrain differs from that which functions in the paraxial mesoderm to generate somites and the axial skeleton. In the prospective hindbrain, cells in the neural epithelia transiently alter their ability to interact with their neighbors, resulting in the ... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2675035 Thu, 06 Aug 2009 20:52:03 +0100 2675035 http://www.medworm.com/index.php?rid=2675034&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19651304%26dopt%3DAbstract Authors: Narita Y, Rijli FM The mammalian hindbrain is the seat of regulation of several vital functions that involve many of the organ systems of the body. Such functions are controlled through the activity of intricate arrays of neuronal circuits and connections. The establishment of ordered patterns of neuronal specification, migration, and axonal topographic connectivity during development is crucial to build such a complex network of circuits and functional connectivity in the mature hindbrain. The early development of the vertebrate hindbrain proceeds according to a fundamental metameric partitioning along the anteroposterior axis into cellular compartments known as rhombomeres. Such an organization has been highly conserved in vertebrate evolution and has a fundamental impact on... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2675034 Thu, 06 Aug 2009 20:52:03 +0100 2675034 http://www.medworm.com/index.php?rid=2675033&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19651305%26dopt%3DAbstract Authors: Dasen JS, Jessell TM Motor behaviors are the primary means by which animals interact with their environment, forming the final output of most central nervous system (CNS) activity. The neural circuits that govern basic locomotor functions appear to be genetically hard wired and are comprised of discrete groups of neurons residing within the spinal cord. These local microcircuits coordinate simple reflexive behaviors in response to sensory stimuli and underlie the generation of rhythmic patterns of neural activity necessary for walking. In recent years there have been significant advances in understanding the genetic and molecular programs that determine the specificity of neural connections within the spinal cord that are critical for the emergence of coordinate motor behavior... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2675033 Thu, 06 Aug 2009 20:52:03 +0100 2675033 http://www.medworm.com/index.php?rid=2675032&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19651306%26dopt%3DAbstract Authors: Iimura T, Denans N, Pourquié O The vertebrate spine exhibits two striking characteristics. The first one is the periodic arrangement of its elements-the vertebrae-along the anteroposterior axis. This segmented organization is the result of somitogenesis, which takes place during organogenesis. The segmentation machinery involves a molecular oscillator-the segmentation clock-which delivers a periodic signal controlling somite production. During embryonic axis elongation, this signal is displaced posteriorly by a system of traveling signaling gradients-the wavefront-which depends on the Wnt, FGF, and retinoic acid pathways. The other characteristic feature of the spine is the subdivision of groups of vertebrae into anatomical domains, such as the cervical, thoracic, lumbar,... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2675032 Thu, 06 Aug 2009 20:52:03 +0100 2675032 http://www.medworm.com/index.php?rid=2675031&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19651307%26dopt%3DAbstract Authors: Young T, Deschamps J Cdx and Hox gene families descend from the same ProtoHox cluster, already present in the common ancestors of bilaterians and cnidarians, and thought to act by providing anteroposterior (A-P) positional identity to axial tissues in all bilaterians. Mouse Cdx and Hox genes still exhibit common features in their early expression and function. The initiation and early shaping of Hox and Cdx transcriptional domains in mouse embryos are very similar, in keeping with their common involvement in conveying A-P information to the nascent tissues during embryonic axial elongation. Considerations of the impact on axial patterning of the early expression phase of these genes that correlates with the temporally collinear expression of 3'-5'Hox genes suggest that it is c... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2675031 Thu, 06 Aug 2009 20:52:03 +0100 2675031 http://www.medworm.com/index.php?rid=2675030&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19651308%26dopt%3DAbstract Authors: Wellik DM The axial skeleton in all vertebrates is comprised of similar structures that extend from anterior to posterior along the body axis: the occipital skull bones, cervical, thoracic, lumbar, sacral and caudal vertebrae. Despite significant changes in the number and size of these elements during vertebrate evolution, the basic character of these anatomical elements, as well as the order in which they appear, has remained strikingly similar. Extensive expression analysis, classic embryology experiments in chick and targeted loss-of-function mutant analyses in mice have clearly demonstrated that Hox genes are key regulators of morphology along the axial skeleton. The cumulative data from this work provides an emerging understanding of Hox gene function in patterning the ve... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2675030 Thu, 06 Aug 2009 20:52:03 +0100 2675030 http://www.medworm.com/index.php?rid=2547232&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19361686%26dopt%3DAbstract Authors: Jeffery WR PMID: 19361686 [PubMed - indexed for MEDLINE] (Source: Current Topics in Developmental Biology) Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2547232 Sun, 28 Jun 2009 04:17:03 +0100 2547232 http://www.medworm.com/index.php?rid=2547231&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19361687%26dopt%3DAbstract Authors: Nikitina N, Sauka-Spengler T, Bronner-Fraser M The neural crest is a multipotent migratory embryonic cell population that is present in all vertebrates, but missing from basal chordates. In this chapter, we discuss recent work in amphioxus, ascidians, lamprey, and gnathostomes that reflects the current state of knowledge of the evolutionary origin of this fascinating cell population. We summarize recent evidence for the ongoing diversification of the neural crest in several vertebrate species, with particular reference to studies in nontraditional vertebrate model organisms. PMID: 19361687 [PubMed - indexed for MEDLINE] (Source: Current Topics in Developmental Biology) Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2547231 Sun, 28 Jun 2009 04:17:03 +0100 2547231 http://www.medworm.com/index.php?rid=2547230&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19361688%26dopt%3DAbstract Authors: Zhang G, Eames BF, Cohn MJ Major advances in the molecular genetics, paleobiology, and the evolutionary developmental biology of vertebrate skeletogenesis have improved our understanding of the early evolution and development of the vertebrate skeleton. These studies have involved genetic analysis of model organisms, human genetics, comparative developmental studies of basal vertebrates and nonvertebrate chordates, and both cladistic and histological analyses of fossil vertebrates. Integration of these studies has led to renaissance in the area of skeletal development and evolution. Among the major findings that have emerged is the discovery of an unexpectedly deep origin of the gene network that regulates chondrogenesis. In this chapter, we discuss recent progress in each the... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2547230 Sun, 28 Jun 2009 04:17:03 +0100 2547230 http://www.medworm.com/index.php?rid=2547229&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19361689%26dopt%3DAbstract Authors: Haag ES A number of major adaptations in animals have been mediated by alteration of germ cells and their immediate derivatives, the gametes. Here, several such cases are discussed, including examples from echinoderms, vertebrates, insects, and nematodes. A feature of germ cells that make their development (and hence evolution) distinct from the soma is the prominent role played by posttranscriptional controls of mRNA translation in the regulation of proliferation and differentiation. This presents a number of special challenges for investigation of the evolution of germline development. Caenorhabditis nematodes represent a particularly favorable system for addressing these challenges, both because of technical advantages and (most importantly) because of natural variation in ... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2547229 Sun, 28 Jun 2009 04:17:03 +0100 2547229 http://www.medworm.com/index.php?rid=2547228&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19361690%26dopt%3DAbstract Authors: Kramer EM The number of genetically tractable plant model systems is rapidly increasing, thanks to the decreasing cost of sequencing and the wide amenability of plants to stable transformation and other functional approaches. In this chapter, I discuss emerging model systems from throughout the land plant phylogeny and consider how their unique attributes are contributing to our understanding of development, evolution, and ecology. These new models are being developed using two distinct strategies: in some cases, they are selected because of their close relationship to the established models, while in others, they are chosen with the explicit intention of exploring distantly related plant lineages. Such complementary approaches are yielding exciting new results that shed light... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2547228 Sun, 28 Jun 2009 04:17:03 +0100 2547228 http://www.medworm.com/index.php?rid=2547227&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19361691%26dopt%3DAbstract Authors: Lambert JD The spiralian developmental program is a highly conserved mode of early development that is characterized by regularities in cleavage pattern, fate map, and larval morphology. It is found in a number of animal phyla, and was likely present in the last common ancestor of the large superphylum Lophotrochozoa. Despite this key position for understanding the evolution of development in animals, and the intrinsic advantages for using spiralian embryos to study embryonic development and asymmetric cell division, very little is known about the molecular mechanisms of spiralian embryogenesis. The snail Ilyanassa has typical spiralian development, as well as a number of practical and experimental advantages that have made it a useful model for understanding spiralian embryog... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2547227 Sun, 28 Jun 2009 04:17:03 +0100 2547227 http://www.medworm.com/index.php?rid=2547226&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19361692%26dopt%3DAbstract Authors: Moczek AP Understanding how development and ecology shape organismal evolution is a central goal of evolutionary developmental biology. This chapter highlights a class of traits and organisms that are emerging as new models in evo-devo and eco-devo research: beetle horns and horned beetles. Horned beetles are morphologically diverse, ecologically rich, and developmentally and genetically increasingly accessible. Recent studies have begun to take advantage of these attributes and are starting to link the microevolution of horned beetle development to the macroevolution of novel features, and to identify the genetic, developmental, and ecological mechanisms, and the interactions between them, that mediate organismal innovation and diversification in natural populations. Here, I ... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2547226 Sun, 28 Jun 2009 04:17:03 +0100 2547226 http://www.medworm.com/index.php?rid=2547225&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19361693%26dopt%3DAbstract Authors: Raff RA, Snoke Smith M Marine invertebrate embryos and larvae are diverse and can evolve rapidly, providing a link between early developmental and evolutionary mechanisms. We here discuss the role of evolutionary changes in axis formation, which is a crucial part of the patterning of marine embryos and larvae. We focus on sea urchin embryos, where axial features are well defined and subject to active current investigation. The genetic control of processes of formation of the three axial systems, animal-vegetal, dorsal-ventral, and left-right, is becoming established for species that undergo development via the feeding pluteus larva. These species represent the primitive condition among living sea urchins. We compare their developmental processes to the highly modified developm... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2547225 Sun, 28 Jun 2009 04:17:03 +0100 2547225 http://www.medworm.com/index.php?rid=2547224&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19361694%26dopt%3DAbstract Authors: Jeffery WR The teleost Astyanax mexicanus is a single species consisting of two radically different forms: a sighted pigmented surface-dwelling form (surface fish) and a blind depigmented cave-dwelling form (cavefish). The two forms of Astyanax have favorable attributes, including descent from a common ancestor, ease of laboratory culture, and the ability to perform genetic analysis, permitting their use as a model system to explore questions in evolution and development. Here, we review current research on the molecular, cellular, and developmental mechanisms underlying the loss of eyes and pigmentation in Astyanax cavefish. Although functional eyes are lacking in adults, cavefish embryos begin to develop eye primordia, which subsequently degenerate. The major cause of eye de... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2547224 Sun, 28 Jun 2009 04:17:03 +0100 2547224 http://www.medworm.com/index.php?rid=2547223&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19427515%26dopt%3DAbstract Authors: Simpson HD, Mortimer D, Goodhill GJ Proper wiring up of the nervous system is critical to the development of organisms capable of complex and adaptable behaviors. Besides the many experimental advances in determining the cellular and molecular machinery that carries out this remarkable task precisely and robustly, theoretical approaches have also proven to be useful tools in analyzing this machinery. A quantitative understanding of these processes can allow us to make predictions, test hypotheses, and appraise established concepts in a new light. Three areas that have been fruitful in this regard are axon guidance, retinotectal mapping, and activity-dependent development. This chapter reviews some of the contributions made by mathematical modeling in these areas, illustrated b... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2547223 Sun, 28 Jun 2009 04:17:03 +0100 2547223 http://www.medworm.com/index.php?rid=2547222&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19427517%26dopt%3DAbstract Authors: Batista-Brito R, Fishell G The central goal of this manuscript is to survey our present knowledge of how cortical interneuron subtypes are generated. To achieve this, we will first define what is meant by subtype diversity. To this end, we begin by considering the mature properties that differentiate between the different populations of cortical interneurons. This requires us to address the difficulties involved in determining which characteristics allow particular interneurons to be assigned to distinct subclasses. Having grappled with this thorny issue, we will then proceed to review the progressive events in development involved in the generation of interneuron diversity. Starting with their origin and specification within the subpallium, we will follow them up through the ... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2547222 Sun, 28 Jun 2009 04:17:03 +0100 2547222 http://www.medworm.com/index.php?rid=2547221&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19427518%26dopt%3DAbstract Authors: Dasen JS The emergence of coordinated locomotor behaviors in vertebrates relies on the establishment of selective connections between discrete populations of neurons present in the spinal cord and peripheral nervous system. The assembly of the circuits necessary for movement presumably requires the generation of many unique cell types to accommodate the intricate connections between motor neurons, sensory neurons, interneurons, and muscle. The specification of diverse neuronal subtypes is mediated largely through networks of transcription factors that operate within progenitor and postmitotic cells. Selective patterns of transcription factor expression appear to define the cell-type-specific cellular programs that govern the axonal guidance decisions and synaptic specificities... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2547221 Sun, 28 Jun 2009 04:17:03 +0100 2547221 http://www.medworm.com/index.php?rid=2547220&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19427519%26dopt%3DAbstract Authors: Li Y, Mu Y, Gage FH The hippocampal formation is widely studied in part because of its distinct and highly laminar organization as well as its demonstrated fundamental role in learning and memory. The dentate gyrus of the hippocampal formation is one of two recognized brain regions that continually generate new neurons in adulthood. In this chapter, we review the basic structure of hippocampal cellular components and circuitry, the properties of stem cells and their progeny in the dentate gyrus, and the known mechanisms and timing of their maturation and integration into the adult circuitry. We also address the functional implication of neurogenesis in the adult hippocampus. PMID: 19427519 [PubMed - in process] (Source: Current Topics in Developmental Biology) Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2547220 Sun, 28 Jun 2009 04:17:03 +0100 2547220 http://www.medworm.com/index.php?rid=2547219&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19427520%26dopt%3DAbstract Authors: Bénard C, Hobert O Neuronal circuitries established in development must persist throughout life. This poses a serious challenge to the structural integrity of an embryonically patterned nervous system as an animal dramatically increases its size postnatally, remodels parts of its anatomy, and incorporates new neurons. In addition, body movements, injury, and ageing generate physical stress on the nervous system. Specific molecular pathways maintain intrinsic properties of neurons in the mature nervous system. Other factors ensure that the overall organization of entire neuronal ensembles into ganglia and fascicles is appropriately maintained upon external challenges. Here, we discuss different molecules underlying these neuronal maintenance mechanisms, with a focus on les... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2547219 Sun, 28 Jun 2009 04:17:03 +0100 2547219 http://www.medworm.com/index.php?rid=1362394&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18282514%26dopt%3DAbstract Authors: Bieker JJ PMID: 18282514 [PubMed - in process] (Source: Current Topics in Developmental Biology) Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1362394 Thu, 10 Apr 2008 09:55:10 +0100 1362394 http://www.medworm.com/index.php?rid=1245047&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18282514%26dopt%3DAbstract Authors: Bieker JJ PMID: 18282514 [PubMed - in process] (Source: Current Topics in Developmental Biology) Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1245047 Wed, 20 Feb 2008 21:12:47 +0100 1245047 http://www.medworm.com/index.php?rid=1245046&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18282515%26dopt%3DAbstract Authors: McGrath K, Palis J Red cells are required not only for adult well-being but also for survival and growth of the mammalian embryo beyond early postimplantation stages of development. The embryo's first "primitive" erythroid cells, derived from a transient wave of committed progenitors, emerge from the yolk sac as immature precursors and differentiate as a semisynchronous cohort in the bloodstream. Surprisingly, this maturational process in the mammalian embryo is characterized by globin gene switching and ultimately by enucleation. The yolk sac also synthesizes a second transient wave of "definitive" erythroid progenitors that enter the bloodstream and seed the liver of the fetus. At the same time, hematopoietic stem cells within the embryo also seed the liver and are the presu... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1245046 Wed, 20 Feb 2008 21:12:47 +0100 1245046 http://www.medworm.com/index.php?rid=1245045&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18282516%26dopt%3DAbstract Authors: Manwani D, Bieker JJ Erythroblastic islands are specialized microenvironmental compartments within which definitive mammalian erythroblasts proliferate and differentiate. These islands consist of a central macrophage that extends cytoplasmic protrusions to a ring of surrounding erythroblasts. The interaction of cells within the erythroblastic island is essential for both early and late stages of erythroid maturation. It has been proposed that early in erythroid maturation the macrophages provide nutrients, proliferative and survival signals to the erythroblasts, and phagocytose extruded erythroblast nuclei at the conclusion of erythroid maturation. There is also accumulating evidence for the role of macrophages in promoting enucleation itself. The central macrophages are ident... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1245045 Wed, 20 Feb 2008 21:12:47 +0100 1245045 http://www.medworm.com/index.php?rid=1245044&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18282517%26dopt%3DAbstract Authors: Wozniak RJ, Bresnick EH Epigenetic mechanisms involving dynamic changes in posttranslational histone modifications commonly control gene transcription and therefore the execution of all cellular differentiation programs. The differentiation of hematopoietic stem cells into specific progenitor cells and the diverse blood cell types represents a particularly powerful system for the study of epigenetic mechanisms. The hematopoietic system allows one to define mechanisms underlying the establishment and regulation of histone modification patterns covering entire genes and/or chromosomes at distinct stages of differentiation. This chapter reviews progress in elucidating principles underlying epigenetic control of complex loci, specifically focusing on genes differentially expressed... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1245044 Wed, 20 Feb 2008 21:12:47 +0100 1245044 http://www.medworm.com/index.php?rid=1245043&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18282518%26dopt%3DAbstract Authors: Ginder GD, Gnanapragasam MN, Mian OY The sequence complexity of the known vertebrate genomes alone is insufficient to account for the diversity between individuals of a species. Although our knowledge of vertebrate biology has evolved substantially with the growing compilation of sequenced genomes, understanding the temporal and spatial regulation of genes remains fundamental to fully exploiting this information. The importance of epigenetic factors in gene regulation was first hypothesized decades ago when biologists posited that methylation of DNA could heritably alter gene expression [Holliday and Pugh, 1975. Science187(4173), 226-232; Riggs, 1975. Cytogenet. and Cell Genet.14(1), 9-25; Scarano et al., 1967. Proc. Natl. Acad. Sci. USA57(5), 1394-1400)]. It was subsequently ... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1245043 Wed, 20 Feb 2008 21:12:47 +0100 1245043 http://www.medworm.com/index.php?rid=1245042&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18282519%26dopt%3DAbstract Authors: de Laat W, Klous P, Kooren J, Noordermeer D, Palstra RJ, Simonis M, Splinter E, Grosveld F The history of globin research is marked by a series of contributions seminal to our understanding of the genome, its function, and its relation to disease. For example, based on studies on hemoglobinopathies, it was understood that gene expression can be under the control of DNA elements that locate away from the genes on the linear chromosome template. Recent technological developments have allowed the demonstration that these regulatory DNA elements communicate with the genes through physical interaction, which loops out the intervening chromatin fiber. Subsequent studies showed that the spatial organization of the beta-globin locus dynamically changes in relation to differences in ge... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1245042 Wed, 20 Feb 2008 21:12:47 +0100 1245042 http://www.medworm.com/index.php?rid=1245041&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18282520%26dopt%3DAbstract Authors: Wrighting DM, Andrews NC Erythrocytes require iron to perform their duty as oxygen carriers. Mammals have evolved a mechanism to maintain systemic iron within an optimal range that fosters erythroid development and function while satisfying other body iron needs. This chapter reviews erythroid iron uptake and utilization as well as systemic factors that influence iron availability. One of these factors is hepcidin, a circulating peptide hormone that maintains iron homeostasis. Elevated levels of hepcidin in the bloodstream effectively shut off iron absorption by disabling the iron exporter ferroportin. Conversely, low levels of circulating hepcidin allow ferroportin to export iron into the bloodstream. Aberrations in hepcidin expression or responsiveness to hepcidin result in ... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1245041 Wed, 20 Feb 2008 21:12:47 +0100 1245041 http://www.medworm.com/index.php?rid=1245040&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18282521%26dopt%3DAbstract Authors: Cokić VP, Schechter AN Nitric oxide (NO) is a diffusible free radical generated primarily by NO synthases (NOS), isoenzymes that convert the l-arginine and molecular oxygen to citrulline and NO in cells. Endothelial cells as well as macrophages, components of hematopoietic microenvironment and potent NO producers, play an active role in the modulation of human hematopoietic cell growth and differentiation. A role of NO in erythroid cell differentiation has been postulated based on demonstration that NO inhibits growth, differentiation, and hemoglobinization of erythroid primary cells. Endothelial NOS (eNOS) mRNA and protein levels, as well as bioactivity, decrease during erythroid differentiation, concomitantly with the elevation of hemoglobin levels. Human red blood cel... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1245040 Wed, 20 Feb 2008 21:12:47 +0100 1245040 http://www.medworm.com/index.php?rid=1245039&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18282522%26dopt%3DAbstract Authors: Ellis SR, Lipton JM Diamond Blackfan anemia (DBA) is an inherited hypoplastic anemia that typically presents in the first year of life. The genes identified to date that are mutated in DBA encode ribosomal proteins, and in these cases ribosomal protein haploinsufficiency gives rise to the disease. The developmental timing of DBA presentation suggests that the changes in red blood cell production that occur around the time of birth trigger a pathophysiological mechanism, likely linked to defective ribosome synthesis, which precipitates the hematopoietic phenotype. Variable presentation of other clinical phenotypes in DBA patients indicates that other developmental pathways may also be affected by ribosomal protein haploinsufficiency and that the involvement of these pathways is... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1245039 Wed, 20 Feb 2008 21:12:47 +0100 1245039 http://www.medworm.com/index.php?rid=1189988&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18023722%26dopt%3DAbstract Authors: Schnell S, Maini PK, Newman SA, Newman TJ PMID: 18023722 [PubMed - indexed for MEDLINE] (Source: Current Topics in Developmental Biology) Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1189988 Thu, 31 Jan 2008 09:02:02 +0100 1189988 http://www.medworm.com/index.php?rid=1041364&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18023722%26dopt%3DAbstract Authors: Schnell S, Maini PK, Newman SA, Newman TJ PMID: 18023722 [PubMed - in process] (Source: Current Topics in Developmental Biology) Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1041364 Wed, 21 Nov 2007 15:05:16 +0100 1041364 http://www.medworm.com/index.php?rid=1041363&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18023723%26dopt%3DAbstract Authors: Meinhardt H An inroad into an understanding of the complex molecular interactions on which development is based can be achieved by uncovering the minimum requirements that describe elementary steps and their linkage. Organizing regions and other signaling centers can be generated by reactions that involve local self-enhancement coupled to antagonistic reactions of longer range. More complex patterns result from a chaining of such reactions in which one pattern generates the prerequisites for the next. Patterning along the single axis of radial symmetric animals including the small freshwater polyp hydra can be explained in this way. The body pattern of such ancestral organisms evolved into the brain of higher organisms, while trunk and midline formation are later evolutionary ... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1041363 Wed, 21 Nov 2007 15:05:16 +0100 1041363 http://www.medworm.com/index.php?rid=1041362&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18023724%26dopt%3DAbstract Authors: Umulis D, O'Connor MB, Othmer HG PMID: 18023724 [PubMed - in process] (Source: Current Topics in Developmental Biology) Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1041362 Wed, 21 Nov 2007 15:05:16 +0100 1041362 http://www.medworm.com/index.php?rid=1041361&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18023725%26dopt%3DAbstract We describe processes operating in the embryo from whole embryo scale, the tissue-scale, to the cellular and extracellular matrix scale. We focus on describing cells, their behaviors and the unique microenvironments they traverse during gastrulation and discuss the role of tissue mechanics in these processes. PMID: 18023725 [PubMed - in process] (Source: Current Topics in Developmental Biology) Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1041361 Wed, 21 Nov 2007 15:05:16 +0100 1041361 http://www.medworm.com/index.php?rid=1041360&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18023726%26dopt%3DAbstract Authors: Chuai M, Weijer CJ Formation of the primitive streak is one of the key events in the early development of amniote embryos. The streak is the site where during gastrulation the mesendoderm cells ingress to take up their correct topographical positions in the embryo. The process of streak formation can be conveniently observed in the chick embryo, where the streak forms as an accumulation of cells in the epiblast in the posterior pole of the embryo and extends subsequently in anterior direction until it covers 80% of the epiblast. A prerequisite for streak formation is the differentiation of mesoderm, which is induced in the epiblast at the interface between the posterior Area Opaca and Area Pellucida in a sickle shaped domain overlying Koller's sickle. Current views on the mole... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1041360 Wed, 21 Nov 2007 15:05:16 +0100 1041360 http://www.medworm.com/index.php?rid=1041359&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18023727%26dopt%3DAbstract Authors: Newman TJ This paper is comprised of two parts. In the first we provide a brief overview of grid-free methods for modeling multicellular systems. We focus on an approach based on Langevin equations, in which inertia is ignored, and stochastic effects on cell motion are included. The discussion starts with simpler models, in which cells are modeled as adhesive spheres. We then turn to more sophisticated approaches in which nontrivial cell shape is accommodated, including the recently introduced Subcellular Element Model, in which each cell is described as a cluster of adhesively coupled over-damped subcellular elements, representing patches of cytoskeleton. In the second part of the paper we illustrate the use of a standard grid-free cell-based model to computationally probe in... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1041359 Wed, 21 Nov 2007 15:05:16 +0100 1041359 http://www.medworm.com/index.php?rid=1041358&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18023728%26dopt%3DAbstract Authors: Baker RE, Schnell S, Maini PK Somitogenesis is the process of division of the anterior-posterior vertebrate embryonic axis into similar morphological units known as somites. These segments generate the prepattern which guides formation of the vertebrae, ribs and other associated features of the body trunk. In this work, we review and discuss a series of mathematical models which account for different stages of somite formation. We begin by presenting current experimental information and mechanisms explaining somite formation, highlighting features which will be included in the models. For each model we outline the mathematical basis, show results of numerical simulations, discuss their successes and shortcomings and avenues for future exploration. We conclude with a brief disc... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1041358 Wed, 21 Nov 2007 15:05:16 +0100 1041358 http://www.medworm.com/index.php?rid=1041357&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18023729%26dopt%3DAbstract Authors: Glazier JA, Zhang Y, Swat M, Zaitlen B, Schnell S During gastrulation in vertebrates, mesenchymal cells at the anterior end of the presomitic mesoderm (PSM) periodically compact, transiently epithelialize and detach from the posterior PSM to form somites. In the prevailing clock-and-wavefront model of somitogenesis, periodic gene expression, particularly of Notch and Wnt, interacts with an FGF8-based thresholding mechanism to determine cell fates. However, this model does not explain how cell determination and subsequent differentiation translates into somite morphology. In this paper, we use computer simulations of chick somitogenesis to show that experimentally-observed temporal and spatial patterns of adhesive N-CAM and N-cadherin and repulsive EphA4-ephrinB2 pairs suffice ... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1041357 Wed, 21 Nov 2007 15:05:16 +0100 1041357 http://www.medworm.com/index.php?rid=1041356&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18023730%26dopt%3DAbstract Authors: Lubkin SR Branching morphogenesis is ubiquitous and important in creating bulk transport systems. Branched ducts can be generated by several different mechanisms including growth, cell rearrangements, contractility, adhesion changes, and other mechanisms. We have developed several models of the mechanics of cleft formation, which we review. We discuss the implications of several candidate mechanisms and review what has been found in models and in experiments. PMID: 18023730 [PubMed - in process] (Source: Current Topics in Developmental Biology) Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1041356 Wed, 21 Nov 2007 15:05:16 +0100 1041356 http://www.medworm.com/index.php?rid=1041355&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18023731%26dopt%3DAbstract Authors: Czirok A, Zamir EA, Szabo A, Little CD Living organisms, from bacteria to vertebrates, are well known to generate sophisticated multicellular patterns. Numerous recent interdisciplinary studies have focused on the formation and regulation of these structures. Advances in automatized microscopy allow the time-resolved tracking of embryonic development at cellular resolution over an extended area covering most of the embryo. The resulting images yield simultaneous information on the motion of multiple tissue components-both cells and extracellular matrix (ECM) fibers. Recent studies on ECM displacements in bird embryos resulted in a method to distinguish tissue deformation and cell-autonomous motion. Patterning of the primary vascular plexus results from a collective action of p... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1041355 Wed, 21 Nov 2007 15:05:16 +0100 1041355 http://www.medworm.com/index.php?rid=1041354&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18023732%26dopt%3DAbstract Authors: Miura T Vertebrate lung has tree-like structure which facilitates gas exchange. After discovery of the involvement of several key toolkit genes-FGF10, BMP4, and Shh, huge amount of molecular information on lung development is now available. However, how their interactions result in a branched structure has not been elucidated. Recently, some studies have utilized mathematical models to understand the mechanism of branching morphogenesis, and we now have some models which are reliable enough to make experimental predictions in the in vitro system. In addition, a different type of modeling, which generates tree-like branching pattern by repeatedly applying a set of simple rules iteratively, is also utilized to model lung function. In this review, I focus on how these models can ... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1041354 Wed, 21 Nov 2007 15:05:16 +0100 1041354 http://www.medworm.com/index.php?rid=1041353&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18023733%26dopt%3DAbstract Authors: Newman SA, Christley S, Glimm T, Hentschel HG, Kazmierczak B, Zhang YT, Zhu J, Alber M Dynamical systems in which geometrically extended model cells produce and interact with diffusible (morphogen) and nondiffusible (extracellular matrix) chemical fields have proved very useful as models for developmental processes. The embryonic vertebrate limb is an apt system for such mathematical and computational modeling since it has been the subject of hundreds of experimental studies, and its normal and variant morphologies and spatiotemporal organization of expressed genes are well known. Because of its stereotypical proximodistally generated increase in the number of parallel skeletal elements, the limb lends itself to being modeled by Turing-type systems which are capable of produci... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1041353 Wed, 21 Nov 2007 15:05:16 +0100 1041353 http://www.medworm.com/index.php?rid=1041352&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18023734%26dopt%3DAbstract Authors: Salazar-Ciudad I One of the aims of developmental biology is to understand how a single egg cell gives rise to the complex spatial distributions of cell types and extracellular components of the adult phenotype. This review discusses the main genetic and epigenetic interactions known to play a role in tooth development and how they can be integrated into coherent models. Along the same lines, several hypotheses about aspects of tooth development that are currently not well understood are evaluated. This is done from their morphological consequences from the model and how these fit known morphological variation and change during tooth development. Thus the aim of this review is two-fold. On one hand the model and its comparison with experimental evidence will be used to outline... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1041352 Wed, 21 Nov 2007 15:05:16 +0100 1041352 http://www.medworm.com/index.php?rid=1041351&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18023735%26dopt%3DAbstract Authors: Meyer-Hermann M Mathematical methods in Biology are of increasing relevance for understanding the control and the dynamics of biological systems with medical relevance. In particular, agent-based methods turn more and more important because of fast increasing computational power which makes even large systems accessible. An overview of different mathematical methods used in Theoretical Biology is provided and a novel agent-based method for cell mechanics based on Delaunay-triangulations and Voronoi-tessellations is explained in more detail: The Delaunay-Object-Dynamics method. It is claimed that the model combines physically realistic cell mechanics with a reasonable computational load. The power of the approach is illustrated with two examples, avascular tumor growth and gene... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1041351 Wed, 21 Nov 2007 15:05:16 +0100 1041351 http://www.medworm.com/index.php?rid=1041350&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18023736%26dopt%3DAbstract Authors: Hatzikirou H, Deutsch A Understanding the precise interplay of moving cells with their typically heterogeneous environment is crucial for central biological processes as embryonic morphogenesis, wound healing, immune reactions or tumor growth. Mathematical models allow for the analysis of cell migration strategies involving complex feedback mechanisms between the cells and their microenvironment. Here, we introduce a cellular automaton (especially lattice-gas cellular automaton-LGCA) as a microscopic model of cell migration together with a (mathematical) tensor characterization of different biological environments. Furthermore, we show how mathematical analysis of the LGCA model can yield an estimate for the cell dispersion speed within a given environment. Novel imaging techn... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1041350 Wed, 21 Nov 2007 15:05:16 +0100 1041350 http://www.medworm.com/index.php?rid=1041349&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18023737%26dopt%3DAbstract Authors: Grima R In the past few decades, it has become increasingly popular and important to utilize mathematical models to understand how microscopic intercellular interactions lead to the macroscopic pattern formation ubiquitous in the biological world. Modeling methodologies come in a large variety and presently it is unclear what is their interrelationship and the assumptions implicit in their use. They can be broadly divided into three categories according to the spatial scale they purport to describe: the molecular, the cellular and the tissue scales. Most models address dynamics at the tissue-scale, few address the cellular scale and very few address the molecular scale. Of course there would be no dissent between models or at least the underlying assumptions would be known if ... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1041349 Wed, 21 Nov 2007 15:05:16 +0100 1041349 http://www.medworm.com/index.php?rid=1041348&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18023738%26dopt%3DAbstract Authors: Flenner E, Marga F, Neagu A, Kosztin I, Forgacs G A distinguishing feature of a multicellular living system is that it operates at various scales, from the intracellular to organismal. Genes and molecules set up the conditions for the physical processes to act, in particular to shape the embryo. As development continues the changes brought about by the physical processes lead to changes in gene expression. It is this coordinated interplay between genetic and generic (i.e., physical and chemical) processes that constitutes the modern understanding of early morphogenesis. It is natural to assume that in this multiscale process the smaller defines the larger. In case of biophysical properties, in particular, those at the subcellular level are expected to give rise to those at the... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1041348 Wed, 21 Nov 2007 15:05:16 +0100 1041348 http://www.medworm.com/index.php?rid=1041347&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18023739%26dopt%3DAbstract Authors: Bellomo N, Forni G This chapter deals with the modeling and simulation of large systems of interacting entities whose microscopic state includes not only geometrical and mechanical variables (typically position and velocity), but also biological functions or specific activities. The main issue looks at the development of a biological mathematical theory for multicellular systems. The first part is devoted to the derivation of mathematical structures to be properly used to model a variety of biological phenomena with special focus on immune competition. Then, some specific applications are proposed referring to the competition between neoplastic and immune cells. Finally, the last part is devoted to research perspectives towards the objective of developing a mathematical-biolog... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1041347 Wed, 21 Nov 2007 15:05:16 +0100 1041347 http://www.medworm.com/index.php?rid=974193&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17950370%26dopt%3DAbstract Authors: Schatten J PMID: 17950370 [PubMed - in process] (Source: Current Topics in Developmental Biology) Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=974193 Wed, 24 Oct 2007 13:28:59 +0100 974193 http://www.medworm.com/index.php?rid=974192&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17950371%26dopt%3DAbstract Authors: Zacchigna S, Almodovar CR, Carmeliet P During evolution vertebrates had to evolve in order to perform more and more complex tasks. To achieve this goal, they developed specialized tissues: a highly branched vascular system to ensure that all tissues receive adequate blood supply, and an intricate nervous system in which nerves branch to transmit electrical signals to peripheral organs. The development of both systems is tightly controlled by a series of developmental cues, which ensure the accomplishment of a complex and highly stereotyped mature network. Vessels and nerves use similar signals and principles to grow, differentiate, and navigate toward their final targets. Both systems share several molecular pathways, highlighting an important link between vascular biology and... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=974192 Wed, 24 Oct 2007 13:28:59 +0100 974192 http://www.medworm.com/index.php?rid=974191&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17950372%26dopt%3DAbstract Authors: Yan HH, Mruk DD, Cheng CY Spermatogenesis that occurs in the seminiferous epithelium of adult mammalian testes is associated with extensive junction restructuring at the Sertoli-Sertoli cell, Sertoli-germ cell, and Sertoli-basement membrane interface. While this morphological phenomenon is known and has been described in great details for decades, the biochemical and molecular changes as well as the mechanisms/signaling pathways that define changes at the cell-cell and cell-matrix interface remain largely unknown until recently. In this chapter, we summarize and discuss findings in the field regarding the coordinated efforts of the anchoring [e.g., adherens junction (AJ), such as basal ectoplasmic specialization (basal ES)] and tight junctions (TJs) that are present in the sam... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=974191 Wed, 24 Oct 2007 13:28:59 +0100 974191 http://www.medworm.com/index.php?rid=974190&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17950373%26dopt%3DAbstract Authors: Oien DB, Moskovitz J Posttranslational modifications can change a protein's structure, function, and solubility. One specific modification caused by reactive oxygen species is the oxidation of the sulfur atom in the methionine (Met) side chain. This modified amino acid is denoted as methionine sulfoxide (MetO). MetOs in proteins are of considerable interest as they are involved in early posttranslational modification events. Thus, various organisms produce specific enzymes that can reverse these modifications. MetO reductases, known collectively as the methionine sulfoxide reductase (Msr) system, are the only known enzymes that can reduce MetOs. The current research field of Met redox cycles is consumed with elucidating its role in regulation, redox homeostasis, prevention of ... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=974190 Wed, 24 Oct 2007 13:28:59 +0100 974190 http://www.medworm.com/index.php?rid=974189&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17950374%26dopt%3DAbstract Authors: Westholm DE, Rumbley JN, Salo DR, Rich TP, Anderson GW Organic anion-transporting polypeptides (Oatps) are solute carrier family members that exhibit marked evolutionary conservation. Mammalian Oatps exhibit wide tissue expression with an emphasis on expression in barrier cells. In the brain, Oatps are expressed in the blood-brain barrier endothelial cells and blood-cerebrospinal fluid barrier epithelial cells. This expression profile serves to illustrate a central role for Oatps in transporting endo- and xenobiotics across brain barrier cells. This chapter will detail the expression patterns and substrate specificities of Oatps expressed in the brain, and will place special emphases on the role of Oatps in prostaglandin synthesis and in the transport of conjugated endobiotics... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=974189 Wed, 24 Oct 2007 13:28:59 +0100 974189 http://www.medworm.com/index.php?rid=974188&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17950375%26dopt%3DAbstract We describe natural and laboratory environments of C. elegans and provide an overview of the different environmental responses of this organism. We then show how two developmental processes respond to changes in the environment. First, we discuss the development of alternative juvenile stages, the dauer and non-dauer larva. This example illustrates how development responds to variation in the environment to generate complex phenotypic variation. Second, we discuss the development of the C. elegans vulva. This example illustrates how development responds to variation in the environment while generating an invariant final phenotype. PMID: 17950375 [PubMed - in process] (Source: Current Topics in Developmental Biology) Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=974188 Wed, 24 Oct 2007 13:28:59 +0100 974188 http://www.medworm.com/index.php?rid=974187&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17950376%26dopt%3DAbstract Authors: Marin F, Luquet G, Marie B, Medakovic D In the last few years, the field of molluscan biomineralization has known a tremendous mutation, regarding fundamental concepts on biomineralization regulation as well as regarding the methods of investigation. The most recent advances deal more particularly with the structure of shell biominerals at nanoscale and the identification of an increasing number of shell matrix protein components. Although the matrix is quantitatively a minor constituent in the shell of mollusks (less than 5% w/w), it is, however, the major component that controls different aspects of the shell formation processes: synthesis of transient amorphous minerals and evolution to crystalline phases, choice of the calcium carbonate polymorph (calcite vs aragonite), or... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=974187 Wed, 24 Oct 2007 13:28:59 +0100 974187 http://www.medworm.com/index.php?rid=974186&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17950377%26dopt%3DAbstract Authors: Hawkins BT, Egleton RD The specialized cerebral microvascular endothelium interacts with the cellular milieu of the brain and extracellular matrix to form a neurovascular unit, one aspect of which is a regulated interface between the blood and central nervous system (CNS). The concept of this blood-brain barrier (BBB) as a dynamically regulated system rather than a static barrier has wide-ranging implications for pathophysiology of the CNS. While in vitro models of the BBB are useful for screening drugs targeted to the CNS and indispensable for studies of cerebral endothelial cell biology, the complex interactions of the neurovascular unit make animal-based models and methods essential tools for understanding the pathophysiology of the BBB. BBB dysfunction is a complication of... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=974186 Wed, 24 Oct 2007 13:28:59 +0100 974186 http://www.medworm.com/index.php?rid=974185&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17950378%26dopt%3DAbstract Authors: Liu J, Denofrio J, Yuan W, Wang Z, McFadden AW, Parise LV Proper platelet function is essential for hemostasis. However, understanding platelet function is complicated by the fact that platelets are anucleate and therefore not amenable to direct genetic manipulations. To study platelet function, several laboratories have developed CHO cell lines expressing platelet proteins or used megakaryocyte-like cell lines. However, these cell culture models are unable to mimic critical platelet functions, most notably agonist-induced activation of integrin alphaIIbbeta3. Mature megakaryocytes, which are platelet precursors, express platelet-specific proteins, and the function of such proteins and signaling pathways appears conserved between the two cell types. Murine megakaryocytes have ... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=974185 Wed, 24 Oct 2007 13:28:59 +0100 974185 http://www.medworm.com/index.php?rid=974184&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17950379%26dopt%3DAbstract Authors: Filippova GN Recent advances in studying long-range chromatin interactions have shifted focus from the transcriptional regulation by nearby regulatory elements to recognition of the role of higher-order chromatin organization within the nucleus. These advances have also suggested that CCCTC-binding factor (CTCF), a known chromatin insulator protein, may play a central role in mediating long-range chromatin interactions, directing DNA segments into transcription factories and/or facilitating interactions with other DNA regions. Several models that describe possible mechanisms for multiple functions of CTCF in establishment and maintenance of epigenetic programs are now emerging. Epigenetics plays an important role in normal development and disease including cancer. CTCF involve... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=974184 Wed, 24 Oct 2007 13:28:59 +0100 974184 http://www.medworm.com/index.php?rid=611800&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17498545%26dopt%3DAbstract Authors: Khan IM, Redman SN, Williams R, Dowthwaite GP, Oldfield SF, Archer CW During vertebrate evolution, successful adaptation of animal limbs to a variety of ecological niches depended largely on the formation and positioning of synovial joints. The function of a joint is to allow smooth articulation between opposing skeletal elements and to transmit biomechanical loads through the structure, and this is achieved through covering the ends of bones with articular cartilage, lubricating the joint with synovial fluid, using ligaments to bind the skeletal elements together, and encapsulating the joint in a protective fibrous layer of tissue. The diversity of limb generation has been proposed to occur through sequential branching and segmentation of precartilaginous skeletal elements al... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=611800 Thu, 17 May 2007 23:52:22 +0100 611800 http://www.medworm.com/index.php?rid=611799&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17498546%26dopt%3DAbstract Authors: Kow LM, Florea C, Schwanzel-Fukuda M, Devidze N, Kami Kia H, Lee A, Zhou J, Maclaughlin D, Donahoe P, Pfaff D This chapter addresses questions regarding lordosis behavior, the most extremely sexually differentiated behavior that has been analyzed for its neural and molecular mechanisms. Analysis of this behavior has proved for the first time that specific biochemical reactions in specific nerve cell groups in the brain determine a mammalian behavior. Lordosis is done by the female but not by the male. How did the process of sexual differentiation occur? A large literature implicates high levels of testosterone during a critical period during development as being responsible for the defeminization of the brain. A new idea, however, offers the possibility of direct genetic influ... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=611799 Thu, 17 May 2007 23:52:22 +0100 611799 http://www.medworm.com/index.php?rid=611798&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17498547%26dopt%3DAbstract Authors: Krymskaya VP, Panettieri RA On the basis of structure, regulation, and kinetic properties, phosphodiesterases (PDEs) represent a superfamily of enzymes divided into 11 subfamilies that catalyze cytosolic levels of 3',5'-cyclic adenosine monophosphate (cAMP) or 3',5'-cyclic guanosine monophosphate (cGMP) to 5'-AMP or 5'-GMP, respectively. PDE4 represents the major PDE expressed in inflammatory cells as well as airway smooth muscle (ASM), and selective PDE4 inhibitors provide a broad spectrum of anti-inflammatory effects such as abrogating cytokine and chemokine release from inflammatory cells and inhibiting inflammatory cell trafficking. Due to cell- and tissue-specific gene expression and regulation, PDEs modulate unique organ-based functions. New tools or compounds that selec... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=611798 Thu, 17 May 2007 23:52:22 +0100 611798 http://www.medworm.com/index.php?rid=611797&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17498548%26dopt%3DAbstract Authors: Jakovcevic D, Harder DR The brain is critically dependent on oxygen and glucose supply for normal function. Various neurovascular control mechanisms assure that the blood supply of the brain is adequate to meet the energy needs of its components. Emerging evidence shows that neuronal activity can control microcirculation using astrocytes as a mediator. Astrocytes can sense neuronal activity and are involved in signal transmission. Synaptic activity triggers an increase in the intracellular calcium concentration [Ca(2+)]i of adjacent astrocytes, stimulating the release of adenosine triphosphate (ATP) and glutamate. The released ATP mediates the propagation of Ca(2+) waves between neighboring astrocytes, thereby recruiting them to mediate adequate cerebrovascular response to neu... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=611797 Thu, 17 May 2007 23:52:22 +0100 611797 http://www.medworm.com/index.php?rid=611793&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17498549%26dopt%3DAbstract Authors: Antonicelli F, Bellon G, Debelle L, Hornebeck W Degradation of elastin, the main amorphous component of elastic fibers, by elastases belonging to the serine, metallo, or cysteine families leads to the generation of elastin fragments, designated as elastokines in keeping with their cytokine-like properties. Generation of elastokines from one of the longest lived protein in human might represent a strong tissue repair signal. Indeed, they (1) exhibit potent chemotactic activity for leukocytes, (2) stimulate fibroblast and smooth muscle cell proliferation, and (3) display proangiogenic activity as potent as VEGF. However, continuous exposure of cells to these matrikines, through increased elastase(s) expression with age, can contribute to the formation of a chronic inflammatory s... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=611793 Thu, 17 May 2007 23:52:22 +0100 611793 http://www.medworm.com/index.php?rid=611785&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17498550%26dopt%3DAbstract Authors: Salipante SJ, Horwitz MS Recent, surprising, and controversial discoveries have challenged conventional concepts regarding the origins and plasticity of stem cells, and their contributions to tissue regeneration, and highlight just how little is known about mammalian development in comparison to simpler model organisms. In the case of the transparent worm, Caenorhabditis elegans, Sulston and colleagues used a microscope to record the birth and death of every cell during its life, and the compilation of this "fate map" represents a milestone achievement of developmental biology. Determining a fate map for mammals or other higher organisms is more complicated because they are opaque, take a long time to mature, and have a tremendous number of cells. Consequently, fate mapping ex... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=611785 Thu, 17 May 2007 23:52:22 +0100 611785 http://www.medworm.com/index.php?rid=560974&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17222698%26dopt%3DAbstract Authors: Ruiz-Pesini E, Díez-Sánchez C, López-Pérez MJ, Enríquez JA We review here the current knowledge related to the metabolic pathways used by spermatozoa to meet their high demands for ATP. This is discussed with special emphasis on one of their key roles, motility. We believe that the controversy among glycolytic and oxidative phosphorylation supporters is artificial and, as it happens in many other cell types, the source of ATP is multiple and depends on external inputs. PMID: 17222698 [PubMed - indexed for MEDLINE] (Source: Current Topics in Developmental Biology) Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=560974 Sun, 22 Apr 2007 23:54:13 +0100 560974 http://www.medworm.com/index.php?rid=560972&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17222699%26dopt%3DAbstract Authors: Dumollard R, Duchen M, Carroll J Mitochondria have long been known to be the powerhouses of the cell but they also contribute to redox and Ca2+ homeostasis, provide intermediary metabolites and store proapoptotic factors. Mitochondria have a unique behavior during development. They are maternally transmitted with little (if any) paternal contribution, and they originate from a restricted founder population, which is amplified during oogenesis. Then, having established the full complement of mitochondria in the fully grown oocyte, there is no further increase of the mitochondrial population during early development. The localization of mitochondria in the egg during maturation and their segregation to blastomeres in the cleaving embryo are strictly regulated. Gradients in the d... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=560972 Sun, 22 Apr 2007 23:54:13 +0100 560972 http://www.medworm.com/index.php?rid=560970&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17222700%26dopt%3DAbstract Authors: May-Panloup P, Chretien MF, Malthiery Y, Reynier P Mitochondria play a primary role in cellular energetic metabolism, homeostasis, and death. They possess their own multicopy genome, which is maternally transmitted. Mitochondria are directly involved at several levels in the reproductive process since their functional status influences the quality of oocytes and contributes to the process of fertilization and embryonic development. This chapter discusses recent findings concerning mitochondrial DNA content and its expression during oogenesis, fertilization, and early embryonic development. PMID: 17222700 [PubMed - indexed for MEDLINE] (Source: Current Topics in Developmental Biology) Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=560970 Sun, 22 Apr 2007 23:54:13 +0100 560970 http://www.medworm.com/index.php?rid=560968&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17222701%26dopt%3DAbstract Authors: Shoubridge EA, Wai T In mammals, mitochondria and mitochondrial DNA (mtDNA) are transmitted through the female germ line. Mature oocytes contain at least 100,000 copies of mtDNA, organized at 1-2 copies per organelle. Despite the high genome copy number, mtDNA sequence variants are observed to segregate rapidly between generations, and this has led to the concept of a developmental bottleneck for the transmission of mtDNA. Ultrastructural investigations of primordial germ cells show that they contain approximately 10 mitochondria, suggesting that mitochondrial biogenesis is arrested during early embryogenesis, and that the mitochondria contributing to the germ cell precursors are simply apportioned from those present in the zygote. Thus, as few as 0.01% of the mitochondria in ... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=560968 Sun, 22 Apr 2007 23:54:13 +0100 560968 http://www.medworm.com/index.php?rid=560966&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17222702%26dopt%3DAbstract Authors: McFarland R, Taylor RW, Turnbull DM Mitochondria are ubiquitous organelles that are intimately involved in many cellular processes, but whose principal task is to provide the energy necessary for normal cell functioning and maintenance. Disruption of this energy supply can have devastating consequences for the cell, organ, and individual. Over the last two decades, mutations in both mitochondrial DNA (mtDNA) and nuclear DNA have been identified as causative in a number of well-characterized clinical syndromes, although for mtDNA mutations in particular, this relationship between genotype and phenotype is often not straightforward. Despite this, a number of epidemiological studies have been undertaken to assess the prevalence of mtDNA mutations and these have highlighted the im... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=560966 Sun, 22 Apr 2007 23:54:13 +0100 560966 http://www.medworm.com/index.php?rid=560964&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17222703%26dopt%3DAbstract Authors: Trounce IA, Pinkert CA Oxidative phosphorylation (OXPHOS) is the only mammalian biochemical pathway dependent on the coordinated assembly of protein subunits encoded by both nuclear and mitochondrial DNA (mtDNA) genes. Cytoplasmic hybrid cells, cybrids, are created by introducing mtDNAs of interest into cells depleted of endogenous mtDNAs, and have been a central tool in unraveling effects of disease-linked mtDNA mutations. In this way, the nuclear genetic complement is held constant so that observed effects on OXPHOS can be linked to the introduced mtDNA. Cybrid studies have confirmed such linkage for many defined, disease-associated mutations. In general, a threshold principle is evident where OXPHOS defects are expressed when the proportion of mutant mtDNA in a heteroplasmi... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=560964 Sun, 22 Apr 2007 23:54:13 +0100 560964 http://www.medworm.com/index.php?rid=560962&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17222704%26dopt%3DAbstract Authors: Fulka H, Fulka J The introduction of different micromanipulation techniques into reproductive and developmental biology has helped us not only to answer many essential biological questions but it is now evident that these techniques also have wide practical applications. In human-assisted reproduction, the most commonly used approach is the injection of a donor sperm into the oocyte cytoplasm--intracytoplasmic sperm injection. It is, however, speculated that with these techniques it would be also possible to improve the oocyte developmental potential especially in those cases when the quality of the cytoplasm is rather poor and thus its function is compromised. Another important application would be the elimination of mutated mitochondrial DNA (mtDNA) by transferring the nucle... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=560962 Sun, 22 Apr 2007 23:54:13 +0100 560962 http://www.medworm.com/index.php?rid=560960&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17222705%26dopt%3DAbstract Authors: Poulton J, Oakeshott P, Kennedy S Families who have had a child die of a severe, maternally inherited mitochondrial DNA (mtDNA) disease are usually desperate to avoid having further affected children. Here we discuss the problems of applying classical genetic management to mtDNA diseases (Poulton and Turnbull, 2000) and the biology underlying these problems. We explain why these disorders have lagged so far behind the genetics revolution. We then outline the directions in which management is likely to develop, including the use of preimplantation genetic diagnosis (PGD). PMID: 17222705 [PubMed - indexed for MEDLINE] (Source: Current Topics in Developmental Biology) Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=560960 Sun, 22 Apr 2007 23:54:13 +0100 560960 http://www.medworm.com/index.php?rid=560958&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17222706%26dopt%3DAbstract Authors: Harvey AJ, Gibson TC, Quebedeaux TM, Brenner CA Many of the assisted reproductive techniques associated with maternal aging, disease states, or implantation failure aim to correct poor developmental capacity. These techniques are highly invasive and require the exchange of nuclear or cytoplasmic material from a donor oocyte to compensate for deficiencies inherent in the affected individual. These techniques are based on the assumption that the cytoplasm of the donor oocyte can effectively substitute the necessary component(s) to enable development to proceed. Several studies have attempted to inject cytoplasm from "normal" (young) donors, into aged eggs, again assuming that beneficial components of the cytoplasm are transferred to restore developmental capacity. These invasive... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=560958 Sun, 22 Apr 2007 23:54:13 +0100 560958 http://www.medworm.com/index.php?rid=560956&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17222707%26dopt%3DAbstract Authors: Bowles EJ, Campbell KH, St John JC Nuclear transfer technology has uses across theoretical and applied applications, but advances are restricted by continued poor success rates and health problems associated with live offspring. Development of reconstructed embryos is dependent upon numerous interlinking factors relating both to the donor cell and the recipient oocyte. For example, abnormalities in gene expression following somatic cell nuclear transfer (SCNT) have been linked with an inability of the oocyte cytoplasm to sufficiently epigenetically reprogram the nucleus. Furthermore, influences on the propagation of mitochondria and mitochondrial DNA (mtDNA) could be of great importance in determining the early developmental potential of NT embryos and contributing to their ge... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=560956 Sun, 22 Apr 2007 23:54:13 +0100 560956 http://www.medworm.com/index.php?rid=560954&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17338913%26dopt%3DAbstract Authors: Carraway KL, Funes M, Workman HC, Sweeney C Mucins are large, heavily O-glycosylated proteins expressed by epithelial tissues. The canonical function of membrane mucins is to provide protection to vulnerable epithelia by forming a steric barrier against assault, and by contributing to the formation of protective extracellular mucin gels. The aberrant overexpression of mucins is thought to contribute to tumor progression by allowing tumor cells to evade immune recognition, and by aiding in the breakdown of cell-cell and cell-matrix contacts to facilitate migration and metastasis. Recent evidence suggests that we should now modify our thinking about mucin function by considering their roles in signaling pathways leading to cellular growth control. Here we review the markedly div... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=560954 Sun, 22 Apr 2007 23:54:13 +0100 560954 http://www.medworm.com/index.php?rid=560952&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17338914%26dopt%3DAbstract Authors: Planès C, Caughey GH Recent investigations point to an important role for peptidases in regulating transcellular ion transport by the epithelial Na(+) channel, ENaC. Several peptidases, including furins and proteasomal hydrolases, modulate ENaC maturation and disposal. More idiosyncratically, apical Na(+) transport by ENaC in polarized epithelia of kidney, airway, and gut is stimulated constitutively by one or more trypsin-family serine peptidases, as revealed by inhibition of amiloride-sensitive Na(+) transport by broad-spectrum antipeptidases, including aprotinin and bikunin/SPINT2. In vitro, the transporting activity of aprotinin-suppressed ENaC can be restored by exposure to trypsin. The prototypical channel-activating peptidase (CAP) is a type 1 membrane-anchored tryptic... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=560952 Sun, 22 Apr 2007 23:54:13 +0100 560952 http://www.medworm.com/index.php?rid=560950&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17338915%26dopt%3DAbstract Authors: Foster BL, Popowics TE, Fong HK, Somerman MJ Substantial advancements have been made in defining the cells and molecular signals that guide tooth crown morphogenesis and development. As a result, very encouraging progress has been made in regenerating crown tissues by using dental stem cells and recombining epithelial and mesenchymal tissues of specific developmental ages. To date, attempts to regenerate a complete tooth, including the critical periodontal tissues of the tooth root, have not been successful. This may be in part due to a lesser degree of understanding of the events leading to the initiation and development of root and periodontal tissues. Controversies still exist regarding the formation of periodontal tissues, including the origins and contributions of cells, ... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=560950 Sun, 22 Apr 2007 23:54:13 +0100 560950 http://www.medworm.com/index.php?rid=560948&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17338916%26dopt%3DAbstract Authors: Garrett IR A major unmet need in the medical field today is the availability of suitable treatments for the ever-increasing incidence of osteoporosis and the treatment of bone deficit conditions. Although therapies exist which prevent bone loss, the options are extremely limited for patients once a substantial loss of skeletal bone mass has occurred. Patients who have reduced bone mass are predisposed to fractures and further morbidity. The FDA recently approved PTH (1-34) (Teriparatide) for the treatment of postmenopausal osteoporosis after both preclinical animal and clinical human studies indicated it induces bone formation. This is the only approved bone anabolic agent available but unfortunately it has limited use, it is relatively expensive and difficult to administer. C... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=560948 Sun, 22 Apr 2007 23:54:13 +0100 560948 http://www.medworm.com/index.php?rid=560946&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17338917%26dopt%3DAbstract Authors: Kondratov RV, Gorbacheva VY, Antoch MP The last two decades have significantly advanced our understanding of the organization of the circadian system at all levels of regulation-molecular, cellular, tissue, and systemic. It has been recognized that the circadian system represents a complex temporal regulatory network, which plays an important role in synchronizing various biological processes within an organism and coordinating them with the environment. It is believed that deregulation of this synchronization may result in the development of various pathologies. However, recent studies using various circadian mutant mouse models have demonstrated that at least some of the components of the molecular oscillator are actively involved in physiological processes not directly rela... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=560946 Sun, 22 Apr 2007 23:54:13 +0100 560946 http://www.medworm.com/index.php?rid=560944&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17338918%26dopt%3DAbstract Authors: Gozuacik D, Kimchi A Autophagy is a physiological and evolutionarily conserved phenomenon maintaining homeostatic functions like protein degradation and organelle turnover. It is rapidly upregulated under conditions leading to cellular stress, such as nutrient or growth factor deprivation, providing an alternative source of intracellular building blocks and substrates for energy generation to enable continuous cell survival. Yet accumulating data provide evidence that the autophagic machinery can be also recruited to kill cells under certain conditions generating a caspase-independent form of programed cell death (PCD), named autophagic cell death. Due to increasing interest in nonapoptotic PCD forms and the development of mammalian genetic tools to study autophagy, autophagic... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=560944 Sun, 22 Apr 2007 23:54:13 +0100 560944 http://www.medworm.com/index.php?rid=561027&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16564333%26dopt%3DAbstract Authors: Wong JL, Wessel GM Fertilization is the union of a single sperm and an egg, an event that results in a diploid embryo. Animals use many mechanisms to achieve this ratio; the most prevalent involves physically blocking the fusion of subsequent sperm. Selective pressures to maintain monospermy have resulted in an elaboration of diverse egg and sperm structures. The processes employed for monospermy are as diverse as the animals that result from this process. Yet, the fundamental molecular requirements for successful monospermic fertilization are similar, implying that animals may have a common ancestral block to polyspermy. Here, we explore this hypothesis, reviewing biochemical, molecular, and genetic discoveries that lend support to a common ancestral mechanism. We also consid... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561027 Sun, 01 Jan 2006 05:00:00 +0100 561027 http://www.medworm.com/index.php?rid=561024&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16564334%26dopt%3DAbstract Authors: Malbon CC, Wang HY Wnt proteins are secreted glycoprotein ligands that regulate critical aspects of development, including cell proliferation, apoptosis, and cell fate. For those pathways downstream from the "canonical" Wnt/beta-catenin signaling, from the "non-canonical" or planar cell polarity (PCP), and from the Wnt-Ca(2+)/cyclic guanosine monophosphate (cGMP) pathway, Wnt activation of its cellular receptor, a member of the superfamily of G-protein-coupled receptor Frizzled family, requires both heterotrimeric G proteins and the phosphoprotein Dishevelled. Our understanding of the roles of Dishevelled proteins in development is evolving and most recent observations suggest that Dishevelled proteins act as scaffolds essential for Wnt signaling, providing docking sites for a... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561024 Sun, 01 Jan 2006 05:00:00 +0100 561024 http://www.medworm.com/index.php?rid=561023&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16564335%26dopt%3DAbstract Authors: Bailey AP, Streit A Sensory placodes are unique domains of thickened ectoderm in the vertebrate head that form important parts of the cranial sensory nervous system, contributing to sense organs and cranial ganglia. They generate many different cell types, ranging from simple lens fibers to neurons and sensory cells. Although progress has been made to identify cell interactions and signaling pathways that induce placodes at precise positions along the neural tube, little is known about how their precursors are specified. Here, we review the evidence that placodes arise from a unique territory, the pre-placodal region, distinct from other ectodermal derivatives. We summarize the cellular and molecular mechanisms that confer pre-placode character and differentiate placode precur... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561023 Sun, 01 Jan 2006 05:00:00 +0100 561023 http://www.medworm.com/index.php?rid=561022&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16564336%26dopt%3DAbstract Authors: Hansen LK, Wilhelm J, Fassett JT Cell behavior is strongly influenced by the extracellular matrix (ECM) to which cells adhere. Both chemical determinants within ECM molecules and mechanical properties of the ECM network regulate cellular response, including proliferation, differentiation, and apoptosis. Type I collagen is the most abundant ECM protein in the body with a complex structure that can be altered in vivo by proteolysis, cross-linking, and other processes. Because of collagen's complex and dynamic nature, it is important to define the changes in cell response to different collagen structures and its underlying mechanisms. This chapter reviews current knowledge of potential mechanisms by which type I collagen affects cell behavior, and it presents data that elucidate ... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561022 Sun, 01 Jan 2006 05:00:00 +0100 561022 http://www.medworm.com/index.php?rid=561021&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16564337%26dopt%3DAbstract Authors: Chuong CM, Wu P, Plikus M, Jiang TX, Bruce Widelitz R To accomplish regenerative medicine, several critical issues in stem cell biology have to be solved, including the identification of sources, the expanding population, building them into organs, and assimilating them to the host. Although many stem cells can now differentiate along certain lineages, knowledge on how to use them to build organs lags behind. Here we focus on topobiological events that bridge this gap, for example, the regulation of number, size, axes, shape, arrangement, and architecture during organogenesis. Rather than reviewing detail molecular pathways known to disrupt organogenesis when perturbed, we highlight conceptual questions at the topobiological level and ask how cellular and molecular mechanisms ... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561021 Sun, 01 Jan 2006 05:00:00 +0100 561021 http://www.medworm.com/index.php?rid=561020&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16564338%26dopt%3DAbstract Authors: Sharp JA, Cane KN, Lefevre C, Arnould JP, Nicholas KR The fur seal (Arctocephalus spp. and Callorhinus spp., members of the pinniped family) is a mammal with the unusual capability to modulate its lactation cycle by turning milk production on and off without the typical mammalian regression and involution of the mammary gland. Lactation has evolved from constraints arising from the spatial and temporal separation of infant nursing and maternal foraging as the mother gives birth and feeds the pup on land while acquisition of nutrients for milk production occurs at sea. The lactation cycle begins with the female fur seal undergoing a perinatal fast of approximately 1 wk, after which time she departs the breeding colony to forage at sea. For the remainder of the long lactation pe... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561020 Sun, 01 Jan 2006 05:00:00 +0100 561020 http://www.medworm.com/index.php?rid=561019&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16782454%26dopt%3DAbstract Authors: Brugmann SA, Tapadia MD, Helms JA The prevailing approach within the field of craniofacial development is focused on finding a balance between tissues (e.g., facial epithelia, neuroectoderm, and neural crest) and molecules (e.g., bone morphogenetic proteins, fibroblast growth factors, Wnts) that play a role in sculpting the face. We are rapidly learning that neither these tissues nor molecular signals are able to act in isolation; in fact, molecular cues are constantly reciprocating signals between the epithelia and the neural crest in order to pattern and mold facial structures. More recently, it has been proposed that this crosstalk is often mediated and organized by discrete organizing centers within the tissues that are able to act as a self-contained unit of developmental... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561019 Sun, 01 Jan 2006 05:00:00 +0100 561019 http://www.medworm.com/index.php?rid=561018&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16782455%26dopt%3DAbstract Authors: Glass DA, Karsenty G Osteoporosis is a common, prevalent, and debilitating condition, particularly in postmenopausal women. Genetics play a major role in determining peak bone mass and fracture risk, but few genes have been demonstrated conclusively to be involved, much less the signaling pathways with which they are affiliated. The identification of mutations in the gene Lrp5, a Wnt coreceptor, as the cause for both osteoporotic and high-bone mass disorders implicated the canonical Wnt signaling pathway in bone mass regulation. Since Lrp5, other Wnt components have been identified as being regulators of bone mass, and Wnt target genes affecting bone homeostasis have begun to be elucidated. This chapter looks at the various components of the canonical Wnt signaling pathway and... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561018 Sun, 01 Jan 2006 05:00:00 +0100 561018 http://www.medworm.com/index.php?rid=561017&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16782456%26dopt%3DAbstract Authors: Breitwieser GE Calcium sensing receptors (CaR) are unique among G-protein-coupled receptors (GPCRs) since both the first (extracellular) and second (intracellular) messengers are Ca(2+). CaR serves to translate small fluctuations in extracellular Ca(2+) into intracellular Ca(2+) oscillations. In many cells and tissues, CaR also acts as a coincidence detector, sensing both changes in extracellular Ca(2+) plus the presence of various allosteric activators including amino acids, polyamines, and/or peptides. CaR oscillations are uniquely shaped by the activating agonist, that is, Ca(2+) triggers sinusoidal oscillations while Ca(2+) plus phenylalanine trigger transient oscillations of lower frequency. The distinct oscillation patterns generated by Ca(2+)versus Ca(2+) plus phenylala... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561017 Sun, 01 Jan 2006 05:00:00 +0100 561017 http://www.medworm.com/index.php?rid=561016&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16782457%26dopt%3DAbstract Authors: Mahadeo DC, Parent CA A fundamental property of multicellular organisms is signal relay, the process by which information is transmitted from one cell to another. The integration of external information, such as nutritional status or developmental cues, is critical to the function of organisms. In addition, the spatial organizations of multicellular organisms require intricate signal relay mechanisms. Signal relay is remarkably exhibited during the life cycle of the social amoebae Dictyostelium discoideum, a eukaryote that retains a simple way of life, yet it has greatly contributed to our knowledge of the mechanisms cells use to communicate and integrate information. This chapter focuses on the molecules and mechanisms that Dictyostelium employs during its life cycle to relay... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561016 Sun, 01 Jan 2006 05:00:00 +0100 561016 http://www.medworm.com/index.php?rid=561015&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16782458%26dopt%3DAbstract Authors: Paré JF, Sherley JL Adult stem cells (ASCs) are the engines that drive the renewal of adult mammalian tissues. They divide continuously, throughout life, to produce new progeny cells that undergo a robust development program of differentiation and maturation to replace older expired tissue cells. The same cell turnover program may function to provide limited repair and regeneration of adult tissues in some cases. The regenerative potential of ASCs drives the current intense interest in adapting them for applications in cell replacement therapy. However, research to explore this potential has been blunted by an unyielding biological problem. ASCs have proven highly refractory to expansion of their numbers and long-term propagation in culture. A review of reported strategies to... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561015 Sun, 01 Jan 2006 05:00:00 +0100 561015 http://www.medworm.com/index.php?rid=561014&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16782459%26dopt%3DAbstract Authors: Cerna D, Camphausen K, Tofilon PJ Due to an increase in the understanding of molecular radiobiology, strategies for enhancing tumor radiosensitivity have begun to focus on targeting the molecules and processes that regulate cellular radioresponse. Toward this end, histone acetylation has begun to receive considerable attention as a potential target for radiosensitization. Histone acetylation, which is determined by the competing actions of histone acetylases (HATs) and histone deacetylases (HDACs), plays a role in regulating chromatin structure and gene expression--two parameters that have long been considered determinants of radioresponse. As a means of modifying histone acetylation status, considerable effort has been put into the development of inhibitors of HDAC activity, ... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561014 Sun, 01 Jan 2006 05:00:00 +0100 561014 http://www.medworm.com/index.php?rid=561013&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16782460%26dopt%3DAbstract Authors: Massey AC, Zhang C, Cuervo AM Different mechanisms target intracellular components for their degradation into lysosomes through what is known as autophagy. In mammals, three main forms of autophagy have been described: macroautophagy, microautophagy, and chaperone-mediated autophagy (CMA). CMA is the only autophagic pathway that allows selective degradation of soluble proteins in lysosomes. In contrast to the other mammalian forms of autophagy, CMA does not require vesicle formation or major changes in the lysosomal membrane. Instead, substrate proteins directly cross the lysosomal membrane to reach the lumen, where they are rapidly degraded. The substrate proteins are targeted to the lysosomal membrane by recognition of a targeting motif (a KFERQ-like motif), by a chaperone c... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561013 Sun, 01 Jan 2006 05:00:00 +0100 561013 http://www.medworm.com/index.php?rid=561012&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16782461%26dopt%3DAbstract Authors: Czirok A, Zamir EA, Filla MB, Little CD, Rongish BJ This chapter focuses on the in vivo macroassembly dynamics of fibronectin and fibrillin-2--two prominent extracellular matrix (ECM) components, present in vertebrate embryos at the earliest stages of development. The ECM is an inherently dynamic structure with a well-defined position fate: ECM filaments are not only anchored to and move with established tissue boundaries, but are repositioned prior to the formation of new anatomical features. We distinguish two ECM filament relocation processes-each operating on different length scales. First, ECM filaments are moved by large-scale tissue motion, which rearranges major organ primordia within the embryo. The second type of motion, on the scale of the individual ECM filaments, ... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561012 Sun, 01 Jan 2006 05:00:00 +0100 561012 http://www.medworm.com/index.php?rid=561011&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16860663%26dopt%3DAbstract Authors: Reggiori F Autophagy is a degradative transport route conserved among all eukaryotic organisms. During starvation, cytoplasmic components are randomly sequestered into large double-membrane vesicles called autophagosomes and delivered into the lysosome/vacuole where they are destroyed. Cells are able to modulate autophagy in response to their needs, and under certain circumstances, cargoes, such as aberrant protein aggregates, organelles, and bacteria can be selectively and exclusively incorporated into autophagosomes. As a result, this pathway plays an active role in many physiological processes, and it is induced in numerous pathological situations because of its ability to rapidly eliminate unwanted structures. Despite the advances in understanding the functions of autophag... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561011 Sun, 01 Jan 2006 05:00:00 +0100 561011 http://www.medworm.com/index.php?rid=561009&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16860664%26dopt%3DAbstract Authors: Schwartz BE, Ahmad K The typical eukaryotic genome packages roughly 6 feet of DNA into a nucleus about 5 mum in diameter, yet this compaction blocks access to the DNA. At the first level of compaction, DNA is wrapped around octamers of core histone proteins to form arrays of nucleosomes. Nucleosomes are sufficient to block access to DNA, and cells must therefore manipulate nucleosomes in the course of activating the genome. Dramatic progress has been made in understanding the mechanisms by which nucleosomes are manipulated. In addition to the major core histones, most eukaryotic genomes also encode additional variant histones, which have some structural similarity. These are targeted to specific loci by coupling specialized nucleosome assembly pathways to DNA replication, tran... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561009 Sun, 01 Jan 2006 05:00:00 +0100 561009 http://www.medworm.com/index.php?rid=561008&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16860665%26dopt%3DAbstract Authors: Bartlett JD, Ganss B, Goldberg M, Moradian-Oldak J, Paine ML, Snead ML, Wen X, White SN, Zhou YL Extracellular matrix proteins control the formation of the inorganic component of hard tissues including bone, dentin, and enamel. The structural proteins expressed primarily in the enamel matrix are amelogenin, ameloblastin, enamelin, and amelotin. Other proteins, like biglycan, are also present in the enamel matrix as well as in other mineralizing and nonmineralizing tissues of mammals. In addition, the presence of sulfated enamel proteins, and "tuft" proteins has been examined and discussed in relation to enamel formation. The structural proteins of the enamel matrix must have specific protein-protein interactions to produce a matrix capable of directing the highly ordered struc... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561008 Sun, 01 Jan 2006 05:00:00 +0100 561008 http://www.medworm.com/index.php?rid=561007&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16860666%26dopt%3DAbstract Authors: Fisher KA, Summer RS The pulmonary vasculature is formed by two distinct mechanisms: vasculogenesis and angiogenesis. During vasculogenesis vessels form by de novo synthesis from cells residing within the distal mesenchyme, while in angiogenesis new vessels sprout from preexisting structures. Both processes require the activity of vascular stem/progenitor cells to differentiate and form the components of the vessel wall. In general, blood vessels are composed of two cell types, endothelial and vascular supporting cells. Isolation of these cells from the lung demonstrates remarkable heterogeneity. In part, this heterogeneity may relate to the various stem and progenitor cells involved in the formation of the pulmonary circulation. Reports indicate that multiple stem/progenitor ... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561007 Sun, 01 Jan 2006 05:00:00 +0100 561007 http://www.medworm.com/index.php?rid=561006&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16860667%26dopt%3DAbstract Authors: Grenda DS, Link DC Neutrophils are critical components of the innate immune response, and persistent neutropenia is associated with a marked susceptibility to infection. There are a number of inherited clinical syndromes in which neutropenia is a prominent feature. A study of these rare disorders has provided insight into the mechanisms regulating normal neutrophil homeostasis. Tremendous progress has been made at defining the genetic basis of these disorders. Herein, progress in understanding the genetic basis and molecular mechanisms of these disorders is discussed. We have focused our discussion on inherited disorders in which neutropenia is the sole or major hematopoietic defect. PMID: 16860667 [PubMed - in process] (Source: Current Topics in Developmental Biology) Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561006 Sun, 01 Jan 2006 05:00:00 +0100 561006 http://www.medworm.com/index.php?rid=561005&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16860668%26dopt%3DAbstract Authors: Edwards DH, Spitzer N Gene expression affects social behavior only through changes in the excitabilities of neural circuits that govern the release of the relevant motor programs. In turn, social behavior affects gene expression only through patterns of sensory stimulation that produce significant activation of relevant portions of the nervous system. In crayfish, social interactions between pairs of animals lead to changes in behavior that mark the formation of a dominance hierarchy. Those changes in behavior result from changes in the excitability of specific neural circuits. In the new subordinate, circuits for offensive behavior become less excitable and those for defensive behavior become more excitable. Serotonin, which is implicated in mechanisms for social dominance in... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561005 Sun, 01 Jan 2006 05:00:00 +0100 561005 http://www.medworm.com/index.php?rid=561004&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16860669%26dopt%3DAbstract Authors: Pauwelyn KA, Verfaillie CM Stem cell research has known an enormous development, and cellular transplantation holds great promise for regenerative medicine. However, some aspects, such as the mechanisms underlying stem cell plasticity (cell fusion vs true transdifferentiation) and the functional improvement after stem cell transplantation, are highly debated. Furthermore, the great variability in methodology used by several groups, sometimes leads to confusing, contradicting results. In this chapter, we review a number of studies in this area with an eye on possible technical and other difficulties in interpretation of the obtained results. PMID: 16860669 [PubMed - in process] (Source: Current Topics in Developmental Biology) Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561004 Sun, 01 Jan 2006 05:00:00 +0100 561004 http://www.medworm.com/index.php?rid=561003&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16860670%26dopt%3DAbstract Authors: Page RE, Scheiner R, Erber J, Amdam GV How does complex social behavior evolve? What are the developmental building blocks of division of labor and specialization, the hallmarks of insect societies? Studies have revealed the developmental origins in the evolution of division of labor and specialization in foraging worker honeybees, the hallmarks of complex insect societies. Selective breeding for a single social trait, the amount of surplus pollen stored in the nest (pollen hoarding) revealed a phenotypic architecture of correlated traits at multiple levels of biological organization in facultatively sterile female worker honeybees. Verification of this phenotypic architecture in "wild-type" bees provided strong support for a "pollen foraging syndrome" that involves increased ... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561003 Sun, 01 Jan 2006 05:00:00 +0100 561003 http://www.medworm.com/index.php?rid=561002&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16984808%26dopt%3DAbstract Authors: Dallas SL, Chen Q, Sivakumar P This chapter will review advances in our understanding of the dynamics of assembly and reorganization of extracellular matrix (ECM) proteins and will highlight the role of fibronectin as a key orchestrator for the assembly of multiple ECM proteins. The dynamic rather than static nature of the ECM will be emphasized by reviewing time-lapse imaging studies in living cell and embryo systems, with a particular focus on fibronectin and members of the fibrillin superfamily. These studies have provided new insights into the assembly and reorganization of ECM fibrillar networks, suggesting that fibril assembly is a hierarchical process, with increasingly larger fibrillar structures formed by the progressive aggregation of smaller units. These studies hav... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561002 Sun, 01 Jan 2006 05:00:00 +0100 561002 http://www.medworm.com/index.php?rid=561001&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16984809%26dopt%3DAbstract Authors: Cowan CM, Raymond LA Huntington's disease (HD) is a progressive neurodegenerative disorder that generally begins in middle age with abnormalities of movement, cognition, personality, and mood. Neuronal loss is most marked among the medium-sized projection neurons of the dorsal striatum. HD is an autosomal dominant genetic disorder caused by a CAG expansion in exon 1 of the HD gene, encoding an expanded polyglutamine (polyQ) tract near the N-terminus of the protein huntingtin. Despite identification of the gene mutation more than a decade ago, the normal function of this ubiquitously expressed protein is still under investigation and the mechanisms underlying selective neurodegeneration in HD remain poorly understood. Detailed postmortem analyses of brains of HD patients have p... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561001 Sun, 01 Jan 2006 05:00:00 +0100 561001 http://www.medworm.com/index.php?rid=561000&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16984810%26dopt%3DAbstract Authors: Boudreau RL, Davidson BL RNA interference (RNAi) mediates gene silencing in a sequence-specific manner and has proven to be an exceptionally valuable discovery for bench scientists. In the laboratory, RNAi technologies provide efficient means for validating drug targets and for performing reverse genetics to study gene function (Friedman and Perrimon, 2004). Patients may also benefit from RNAi as applications extend to potential human therapies. RNAi-based treatments are being investigated and may provide hope for patients suffering from cancer, viral infections, or genetic diseases for which effective therapies are currently lacking. Notably, several independent studies have demonstrated that RNAi therapy can improve disease phenotypes in various mouse models of human disease... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561000 Sun, 01 Jan 2006 05:00:00 +0100 561000 http://www.medworm.com/index.php?rid=560999&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16984811%26dopt%3DAbstract Authors: Hubmacher D, Tiedemann K, Reinhardt DP Fibrillins are large proteins that form extracellular microfibril suprastructures ubiquitously found in elastic and nonelastic tissues. Mutations in fibrillin-1 and -2 lead to a number of heritable connective tissue disorders generally termed fibrillinopathies. Clinical symptoms in fibrillinopathies manifest in the skeletal, ocular, and cardiovascular systems and highlight the importance of fibrillins in development and homeostasis of tissues and organs, including blood vessels, bone, and eye. Microfibrils appear to have dual roles in (1) conferring mechanical stability and limited elasticity to tissues, and (2) modulating the activity of growth factors of the transforming growth factor beta (TGF-beta) superfamily. This chapter's focus is... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=560999 Sun, 01 Jan 2006 05:00:00 +0100 560999 http://www.medworm.com/index.php?rid=560998&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16984812%26dopt%3DAbstract Authors: Maupin-Furlow JA, Humbard MA, Kirkland PA, Li W, Reuter CJ, Wright AJ, Zhou G Insight into the world of proteolysis has expanded considerably over the past decade. Energy-dependent proteases, such as the proteasome, are no longer viewed as nonspecific degradative enzymes associated solely with protein catabolism but are intimately involved in controlling biological processes that span life to death. The proteasome maintains this exquisite control by catalyzing the precisely timed and rapid turnover of key regulatory proteins. Proteasomes also interplay with chaperones to ensure protein quality and to readjust the composition of the proteome following stress. Archaea encode proteasomes that are highly related to those of eukaryotes in basic structure and function. Investigation... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=560998 Sun, 01 Jan 2006 05:00:00 +0100 560998 http://www.medworm.com/index.php?rid=560996&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16984813%26dopt%3DAbstract Authors: Shepherd VA Water was called by Szent-Gyorgi "life's mater and matrix, mother and medium." This chapter considers both aspects of his statement. Many astrobiologists argue that some, if not all, of Earth's water arrived during cometary bombardments. Amorphous water ices of comets possibly facilitated organization of complex organic molecules, kick-starting prebiotic evolution. In Gaian theory, Earth retains its water as a consequence of biological activity. The cell cytomatrix is a proteinaceous matrix/lattice incorporating the cytoskeleton, a pervasive, holistic superstructural network that integrates metabolic pathways. Enzymes of metabolic pathways are ordered in supramolecular clusters (metabolons) associated with cytoskeleton and/or membranes. Metabolic intermediates are ... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=560996 Sun, 01 Jan 2006 05:00:00 +0100 560996 http://www.medworm.com/index.php?rid=560994&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16984814%26dopt%3DAbstract Authors: Lynch MJ, Hill EV, Houslay MD The phosphodiesterase-4 (PDE4) enzyme belongs to a family of cAMP-dependent phosphodiesterases that provide the major means of hydrolyzing and, thereby, inactivating the key intracellular second messenger, cAMP. As such, PDE4s are central to the regulation of many diverse signaling processes that allow cells to respond to external stimuli. Four genes (4A, 4B, 4C, and 4D) encode around 20 distinct isoform members of the PDE4 family. Each isoform is characterized by a unique N-terminal region. PDE4s are multidomain metallohydrolases with each domain serving particular roles allowing them to be targeted to varying regions and organelles of intracellular space and regulated in distinct fashions by phosphorylation and protein-protein interaction. Altho... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=560994 Sun, 01 Jan 2006 05:00:00 +0100 560994 http://www.medworm.com/index.php?rid=560992&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17118262%26dopt%3DAbstract Authors: Pogue R, Lyons K Transforming growth factor-beta (TGF-beta) superfamily members play diverse roles in all aspects of cartilage development and maintenance. It is well established that TGF-betas and bone morphogenetic proteins (BMPs) play distinct roles in the growth plate. This chapter discusses key experiments and experimental approaches that have revealed these roles, and progress toward the identification of previously unsuspected roles. Current understanding of the mechanisms by which different TGF-beta and BMP pathways exert their functions is discussed. Finally attempts to utilize this information to promote cartilage regeneration, and important issues for future research, are outlined. PMID: 17118262 [PubMed - indexed for MEDLINE] (Source: Current Topics in Developm... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=560992 Sun, 01 Jan 2006 05:00:00 +0100 560992 http://www.medworm.com/index.php?rid=560989&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17118263%26dopt%3DAbstract Authors: Miller RK, D'Silva S, Moore JK, Goodson HV Bik1p is the yeast Saccharomyces cerevisiae representative of the CLIP-170 family of microtubule plus-end tracking proteins. Bik1p shares a number of similarities with its mammalian counterpart CLIP-170, including an important role in dynein function. However, Bik1p and CLIP-170 differ in several significant ways, including the mechanisms utilized to track microtubule plus ends. In addition to presenting functional comparisons between Bik1p and CLIP-170, we provide sequence analyses that reveal previously unrecognized similarities between Bik1p and its animal counterparts. We examine in detail what is known about the functions of Bik1p and consider the various roles that Bik1p plays in positioning the yeast mitotic spindle. This chapt... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=560989 Sun, 01 Jan 2006 05:00:00 +0100 560989 http://www.medworm.com/index.php?rid=560987&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17118264%26dopt%3DAbstract Authors: Williams A, Jahreiss L, Sarkar S, Saiki S, Menzies FM, Ravikumar B, Rubinsztein DC Intracellular protein misfolding/aggregation are features of many late-onset neurodegenerative diseases, called proteinopathies. These include Alzheimer's disease, Parkinson's disease, tauopathies, and polyglutamine expansion diseases [e.g., Huntington's disease; and various spinocerebellar ataxias (SCAs), like SCA3]. There are no effective strategies to slow or prevent the neurodegeneration resulting from these diseases in humans. The mutations causing many proteinopathies (e.g., polyglutamine diseases and tauopathies) confer novel toxic functions on the specific protein, and disease severity frequently correlates with the expression levels of the protein. Thus, the factors regulating the synth... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=560987 Sun, 01 Jan 2006 05:00:00 +0100 560987 http://www.medworm.com/index.php?rid=560985&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17118265%26dopt%3DAbstract Authors: Baron R, Rawadi G, Roman-Roman S The identification of a link between bone mass in humans and gain- [high bone mass (HBM) trait] or loss-of-function [osteoporosis pseudoglioma (OPPG) syndrome] mutations in the Wnt coreceptor lipoprotein receptor-related protein (LRP)5 or in the Wnt antagonist sclerostin (sclerosteosis, Van Buchem syndrome) has called the attention of academic and industry scientists and clinicians to the importance of this signaling pathway in skeletal biology and disease. Multiple genetic and pharmacological manipulations of Wnt signaling in mice have since then confirmed the central role of this pathway in both the establishment of peak bone mass and its maintenance throughout life. Wnt signaling appears to be located downstream of bone morphogenetic protein... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=560985 Sun, 01 Jan 2006 05:00:00 +0100 560985 http://www.medworm.com/index.php?rid=560981&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17118266%26dopt%3DAbstract Authors: Tabancay AP, Forsburg SL There has been remarkable progress in the last 20 years in defining the molecular mechanisms that regulate initiation of DNA synthesis in eukaryotic cells. Replication origins in the DNA nucleate the ordered assembly of protein factors to form a prereplication complex (preRC) that is poised for DNA synthesis. Transition of the preRC to an active initiation complex is regulated by cyclin-dependent kinases and other signaling molecules, which promote further protein assembly and activate the mini chromosome maintenance helicase. We will review these mechanisms and describe the state of knowledge about the proteins involved. However, we will also consider an additional layer of complexity. The DNA in the cell is packaged with histone proteins into chromat... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=560981 Sun, 01 Jan 2006 05:00:00 +0100 560981 http://www.medworm.com/index.php?rid=560978&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17118267%26dopt%3DAbstract Authors: Hansen D, Schedl T The germ line of sexually reproducing animals, at some point in development, consists of both proliferating and differentiating cells. Proliferation is needed to increase cell number, ensuring that a sufficient quantity of gametes is produced. Meiotic development is needed to produce gametes that can support embryogenesis, each with half the ploidy of the somatic cells. For the reproductive strategy of a given species, regulating the timing and number of gametes, and thus controlling the timing of differentiation and the extent of proliferation, is very important for reproductive fitness. Therefore, animals have evolved regulatory mechanisms that tightly control and balance the proliferation-initiation of meiotic development (meiotic entry) decision. Genetic... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=560978 Sun, 01 Jan 2006 05:00:00 +0100 560978 http://www.medworm.com/index.php?rid=560975&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17118268%26dopt%3DAbstract Authors: Hickey MM, Simon MC Maintenance of oxygen homeostasis is critical for the survival of multicellular organs. As a result, both invertebrates and vertebrates have developed highly specialized mechanisms to sense changes in oxygen levels and to mount adequate cellular and systemic responses to these changes. Hypoxia, or low oxygen tension, occurs in physiological situations such as during embryonic development, as well as in pathological conditions such as ischemia, wound healing, and cancer. A primary effector of the adaptive response to hypoxia in mammals is the hypoxia-inducible factor (HIF) family of transcription regulators. These proteins activate the expression of a broad range of genes that mediate many of the responses to decreased oxygen concentration, including enhance... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=560975 Sun, 01 Jan 2006 05:00:00 +0100 560975 http://www.medworm.com/index.php?rid=561135&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15949532%26dopt%3DAbstract In conclusion, EGF-CFC proteins play dual roles as embryonic pattern formation genes and as oncogenes. While during embryogenesis EGF-CFC proteins perform specific and regulatory functions related to cell and tissue patterning, inappropriate expression of these molecules in adult tissues can lead to cellular proliferation and transformation and therefore may be important in the etiology and/or progression of cancer. PMID: 15949532 [PubMed - in process] (Source: Current Topics in Developmental Biology) Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561135 Sat, 01 Jan 2005 05:00:00 +0100 561135 http://www.medworm.com/index.php?rid=561134&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15949533%26dopt%3DAbstract Authors: Bozhkov PV, Filonova LH, Suarez MF Successful embryonic development in plants, as in animals, requires a strict coordination of cell proliferation, cell differentiation, and cell-death programs. The role of cell death is especially critical for the establishment of polarity at early stages of plant embryogenesis, when the differentiation of the temporary structure, the suspensor, is followed by its programmed elimination. Here, we review the emerging knowledge of this and other functions of programmed cell death during plant embryogenesis, as revealed by developmental analyses of Arabidopsis embryo-specific mutants and gymnosperm (spruce and pine) model embryonic systems. Cell biological studies in these model systems have helped to identify and order the cellular processes oc... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561134 Sat, 01 Jan 2005 05:00:00 +0100 561134 http://www.medworm.com/index.php?rid=561133&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15949534%26dopt%3DAbstract Authors: Boassa D, Yool AJ The choroid plexus is a specialized tissue that lines subdomains within the four ventricles of the brain where most of the cerebrospinal fluid is produced. Maintenance of an equilibrium in volume and composition of the cerebrospinal fluid (CSF) is vital for a normal brain function, ensuring an optimal environment for the neurons. The necessarily high water permeability of the choroid plexus barrier is made possible by the abundant expression of a water channel, Aquaporin-1 (AQP1), on the apical side of the membrane from early stages of development through adulthood. Data from studies of AQP1 suggest that it also can contribute as a gated ion channel, and suggest that the AQP1-mediated ionic conductance has physiological significance for the regulation of cere... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561133 Sat, 01 Jan 2005 05:00:00 +0100 561133 http://www.medworm.com/index.php?rid=561132&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15949535%26dopt%3DAbstract Authors: Zhao AZ The 3', 5'-cyclic adenosine monophosphate (cAMP) is a classic second messenger that is intimately involved in the regulation of food intake at the hypothalamus. cAMP can mediate the orexigenic and anorectic effects of various peripheral hormones or neuropeptides in a region-specific and neuron-specific manner. The importance of cAMP is particularly highlighted in a series of findings about cAMP transducing the anorectic signals of leptin and alpha-msh. This chapter provides an overview of several studies on how regulation of food intake takes place with cAMP as the second messenger in the hypothalamus. PMID: 15949535 [PubMed - in process] (Source: Current Topics in Developmental Biology) Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561132 Sat, 01 Jan 2005 05:00:00 +0100 561132 http://www.medworm.com/index.php?rid=561129&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15949536%26dopt%3DAbstract Authors: Hoikkala A, Klappert K, Mazzi D D. montana (a species of the D. virilis group) has spread over the northern hemisphere, populations from different areas showing both genetic and phenotypic divergence. The males of this species produce an elaborate courtship song, which plays a major role both in species recognition and in intraspecific mate choice. The genetic architecture and physical constraints, as well as the importance of the signal for species recognition, set boundaries within which this signal can vary. Within these limits, courtship song parameters may change, depending on the males' physical condition and on the environment they inhabit. Females are likely to affect song evolution by exerting directional selection toward higher carrier frequencies. Given this complex... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561129 Sat, 01 Jan 2005 05:00:00 +0100 561129 http://www.medworm.com/index.php?rid=561125&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15949537%26dopt%3DAbstract Authors: Theo Schermuly R, Ardeschir Ghofrani H, Weissmann N Pulmonary arterial hypertension (PAH) is a progressive disease with a poor prognosis, characterized by intimal lesions, medial hypertrophy, and adventitial thickening of precapillary pulmonary arteries. Several approved therapies are currently available for the treatment of PAH, of which intravenous epoprostenol is the best explored over the past decade. Newly available oral endothelin receptor antagonists, although clinically efficacious, bear the risk of liver toxicity in a significant portion of patients. Substances that stimulate the formation of the second messengers cyclic adenosine monophosphate (cAMP) or guanosine monophosphate (cGMP) have proved useful in the treatment of various forms of pre-capillary pulmonary hype... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561125 Sat, 01 Jan 2005 05:00:00 +0100 561125 http://www.medworm.com/index.php?rid=561122&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15949538%26dopt%3DAbstract Authors: Thomas D, Guthridge M, Woodcock J, Lopez A Tyrosine and serine phosphorylation are central to cellular signaling in growth and development. 14-3-3 proteins function as dimeric phosphoserine-binding proteins with documented interactions throughout the eukaryotic proteome and are highly conserved in both the animal and plant kingdoms. Binding of 14-3-3 to a client protein can have a range of context-dependent effects, including conformational change, enzyme inhibition, a shielding effect, re-localization, and bridging between two molecules. Proteome-based strategies utilizing mass spectrometry have revealed an unprecedented central stage for 14-3-3 in signal transduction with interacting partners composing at least 0.6% of the cellular proteome. 14-3-3 has been shown to bind to ... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561122 Sat, 01 Jan 2005 05:00:00 +0100 561122 http://www.medworm.com/index.php?rid=561120&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15949539%26dopt%3DAbstract Authors: Sonoyama W, Coppe C, Gronthos S, Shi S Postnatal stem cells have been isolated from a variety of tissues and they are highly expected to have potentiality to be utilized for cell-based clinical therapies. Bone marrow stromal stem cells (BMSSCs) derived from bone marrow stromal tissue have been identified as a population of multipotent mesenchymal stem cells that are capable of differentiating into osteoblasts, adipocytes, chondrocytes, muscle cells, and neural cells. The most significant tissue regeneration trait of BMSSCs is their in vivo bone regeneration capability, which has been widely studied for understanding molecular and cellular mechanisms of osteogenesis, and, more importantly, developing into a stem-cell-based therapy. Recent studies further demonstrated that BMSSC... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561120 Sat, 01 Jan 2005 05:00:00 +0100 561120 http://www.medworm.com/index.php?rid=561118&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16124994%26dopt%3DAbstract Authors: Chilton BS, Hewetson A Prolactin (PRL) and growth hormone (GH) act by way of their receptors as either hormones (systemically) or cytokines (locally). The Jak2/Stat5 pathway is the principal route by which PRL/GH activate target genes. The availability of knockout mice for each member of this signaling cascade has provided opportunities to understand their unique interactions. Jak2 is important in alternative signal transduction schema such as the MAP kinase and PI3K/Akt pathways. The putative Jak2/RUSH pathway is based on the fact that RUSH mediates the ability of PRL to augment progesterone-dependent gene transcription. New evidence shows that suppressors, regulators, and degraders control Jak2/Stat5. This review focuses on the most recent advances in the field of PRL/GH sig... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561118 Sat, 01 Jan 2005 05:00:00 +0100 561118 http://www.medworm.com/index.php?rid=561115&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16124995%26dopt%3DAbstract Authors: Movsesian MA, Bristow MR Dilated cardiomyopathy is a disease characterized by enlargement of the chambers of the heart and a decrease in contractility of the heart muscle. The process involves several alterations in proteins involved in cyclic adenosine monophosphate (cAMP) generation that result in a decrease in intracellular cAMP content per unit of adrenergic stimulation in cardiac myocytes. A fundamental question is whether these changes constitute a pathologic mechanism that contributes to chamber enlargement and hypocontractility or a compensatory adaptation that protects the heart from the adverse effects of increased catecholamine stimulation. Clinical studies in humans suggest that the latter effect may be more important. Studies in animal models, however, make the pi... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561115 Sat, 01 Jan 2005 05:00:00 +0100 561115 http://www.medworm.com/index.php?rid=561112&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16124996%26dopt%3DAbstract Authors: Bachelot A, Binart N The corpus luteum is a transient endocrine gland that produces essentially progesterone, a required product for the establishment and maintenance of early pregnancy. In the absence of pregnancy, the corpus luteum will cease to produce progesterone, and the structure itself will regress in size over time. The life span and function of the corpus luteum is regulated by complex interactions between stimulatory (luteotrophic) and inhibitory (luteolytic) mediators. Although the process of luteal formation and regression has been studied for several decades, many of the regulatory mechanisms involved in loss of function and involution of the structure are incompletely understood. In rodents, prolactin is the major luteotrophic hormone by maintaining the structur... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561112 Sat, 01 Jan 2005 05:00:00 +0100 561112 http://www.medworm.com/index.php?rid=561109&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16124997%26dopt%3DAbstract Authors: Spencer TE, Hayashi K, Hu J, Carpenter KD The uterus is an essential organ for reproduction in mammals. Despite the importance of the uterus for the fertility and health of women and their offspring, relatively little is known about the hormonal, cellular, and molecular mechanisms that regulate development of the uterus in either the fetus or neonate. Disruption of uterine development in the fetus and neonate by genetic defects or exposure to endocrine disruptors can program the function of the uterus in the adult and lead to infertility, cancer, and even death. The intent of this chapter is to review the current knowledge of regulatory factors and pathways governing prenatal organogenesis and postnatal morphogenesis of the uterus in mammals, with a particular focus on laborat... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561109 Sat, 01 Jan 2005 05:00:00 +0100 561109 http://www.medworm.com/index.php?rid=561101&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16124998%26dopt%3DAbstract Authors: Karakelides H, Sreekumaran Nair K Sarcopenia contributes significantly to the morbidity, decrease in quality of life, and health care costs in the elderly. It is characterized by a decrease in muscle mass and strength, starting as early as the fourth decade of life in humans. Distinct muscle changes include a decrease in type 2 muscle fibers and a decrease in myosin heavy chains IIa and IIx mRNA levels. In addition, a decrease in whole body protein turnover, mixed muscle protein synthesis, myosin heavy chain synthesis, and mitochondrial protein synthesis have been reported. Different tissues and organs display different responses to aging, with more oxidative tissue generally having more age-related changes. Exercise has been shown to increase strength, aerobic capacity, and m... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561101 Sat, 01 Jan 2005 05:00:00 +0100 561101 http://www.medworm.com/index.php?rid=561095&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16124999%26dopt%3DAbstract Authors: Liu L, Callahan MK, Huang D, Ransohoff RM CXCR3, the receptor for CXCL9/MIG, CXCL10/IP-10, and CXCL11/I-TAC, is preferentially expressed on activated Th1 T cells and has been predicted to play an important role in their trafficking. However, this simplistic view of the function of CXCR3 and its ligands has not been borne out by studies of disease models, including experimental autoimmune encephalomyelitis (EAE), using varied methods of receptor blockade, as well as knockout or transgenic mice. This review focuses on the current understanding of the enigmatic role of CXCR3 and its ligands in CNS inflammatory/autoimmune disorders. The conflicting results among varied models of CNS inflammation suggest complex and multiple roles for CXCR3 and its ligands in the pathogenesis of CN... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561095 Sat, 01 Jan 2005 05:00:00 +0100 561095 http://www.medworm.com/index.php?rid=561092&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16125000%26dopt%3DAbstract Authors: Sepulveda JL, Gkretsi V, Wu C Cell-extracellular matrix (ECM) adhesion is crucial for control of cell behavior. It connects the ECM to the intracellular cytoskeleton and transduces bidirectional signals between the extracellular and intracellular compartments. The subcellular machinery that mediates cell-ECM adhesion and signaling is complex. It consists of transmembrane proteins (e.g., integrins) and at least several dozens of membrane-proximal proteins that assemble into a network through multiple protein interactions. Furthermore, despite sharing certain common components, cell-ECM adhesions exhibit considerable heterogeneity in different types of cells (e.g., the cell-ECM adhesions in cardiac myocytes are considerably different from those in fibroblasts). Here, we will fir... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561092 Sat, 01 Jan 2005 05:00:00 +0100 561092 http://www.medworm.com/index.php?rid=561086&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16125001%26dopt%3DAbstract Authors: Wang H Higher plants monitor changes in the ambient light environment using three major classes of photoreceptors: the red/far-red-absorbing phytochromes, the blue/UV-A-absorbing cryptochromes, and phototropins. These photoreceptors mediate various photoresponses, ranging from seed germination, to seedling de-etiolation, stem elongation, leaf expansion, floral initiation, phototropic bending of organs, intracellular movement of chloroplast, and stomata opening. Here I briefly review the distinct and overlapping physiological functions of these photoreceptors and highlight recent progress that provided significant insights into their signaling mechanisms, particularly from a structure-function perspective. This review focuses on the early photochemical and biochemical events th... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561086 Sat, 01 Jan 2005 05:00:00 +0100 561086 http://www.medworm.com/index.php?rid=561084&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16125002%26dopt%3DAbstract Authors: Urish K, Kanda Y, Huard J Myoblast transfer therapy can restore dystrophin expressing myofibers in mdx mice and patients with Duchenne muscular dystrophy (DMD). However, the effectiveness of this technique is hindered by numerous limitations, including minimal distribution of cells after injection, immune rejection, and poor cell survival. Initial studies revealed that only a small population of cells was responsible for muscle regeneration. Compared with myoblast transplantation, the injection of a population of myogenic cells purified with the pre-plate technique results in a superior regeneration of dystrophin-expressing myofibers. These postnatal muscle-derived stem cells (MDSC) undergo self-renewal, display long-term proliferation, and differentiate into multiple lineages... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561084 Sat, 01 Jan 2005 05:00:00 +0100 561084 http://www.medworm.com/index.php?rid=561082&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16125003%26dopt%3DAbstract Authors: Darling DL, Yingling J, Wynshaw-Boris A 14-3-3 genes encode a ubiquitous family of highly conserved eukaryotic proteins from fungi to humans and plants with several molecular and cellular functions. Most notably, 14-3-3 proteins bind to phosphoserine/phosphothreonine motifs in a sequence-specific manner. More than 100 14-3-3 binding partners involved in signal transduction, cell cycle regulation, apoptosis, stress responses, and malignant transformation have been identified. The 14-3-3 proteins form homodimers and heterodimers, and there is redundancy of the binding specificity and function of different 14-3-3 proteins because of their highly similar amino acid sequence and tertiary structure. 14-3-3 proteins can regulate target protein function by several mechanisms. Although... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561082 Sat, 01 Jan 2005 05:00:00 +0100 561082 http://www.medworm.com/index.php?rid=561080&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16125004%26dopt%3DAbstract Authors: Falciatore A, Bowler C Photoreceptors allow living organisms to optimize perception of light in the natural environment and thus to gain information about their external world. In this review, we describe blue and red light photoreceptors in bacteria, plants, and animals in relation to their evolution. Analyses performed in different organisms have revealed wonderful examples of structural modifications of the light-sensing proteins themselves, as well as diversification of the signal transduction pathways they use in relation with their evolutionary history and function. In different organisms, the same photoreceptor may have a very conserved role (convergent evolution of function) or may modulate different responses (acquisition of new function). Multiple photoreceptors of t... Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561080 Sat, 01 Jan 2005 05:00:00 +0100 561080 http://www.medworm.com/index.php?rid=561074&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16243594%26dopt%3DAbstract Authors: Mikeladze-Dvali T, Desplan C, Pistillo D Color vision in Drosophila melanogaster relies on the presence of two different subtypes of ommatidia: the "green" and "blue." These two classes are distributed randomly throughout the retina. The decision of a given ommatidium to take on the "green" or "blue" fate seems to be based on a stochastic mechanism. Here we compare the stochastic choice of photoreceptors in the fly retina with other known examples of random choices in both sensory and other systems. PMID: 16243594 [PubMed - in process] (Source: Current Topics in Developmental Biology) Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561074 Sat, 01 Jan 2005 05:00:00 +0100 561074 http://www.medworm.com/index.php?rid=561071&cid=s_35505_62_f&fid=35505&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16243595%26dopt%3DAbstract Authors: Hébert JM The telencephalon, at the rostral end of the developing central nervous system, starts off as a sheet of neuroepithelial cells. During development, this sheet of cells becomes patterned and morphologically partitioned into areas that give rise to the adult cerebral hemispheres. How does this happen? How are telencephalic precursor cells instructed to generate myriad neural cell types in different areas and at different times as well as to change their rates of cell proliferation, differentiation, and death? The molecular pathways required for patterning the telencephalic neuroepithelium and forming the cerebral hemispheres are beginning to be unraveled. PMID: 16243595 [PubMed - in process] (Source: Current Topics in Developmental Biology) Current Topics in Developmental Biology journals http://www.medworm.com/rss/comments.php?id=561071 Sat, 01 Jan 2005 05:00:00 +0100 561071