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 'BioEssays' source. Mon, 06 Feb 2012 16:52:01 +0100 http://www.medworm.com/index.php?rid=5643840&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100179 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5643840 Tue, 31 Jan 2012 14:45:50 +0100 5643840 http://www.medworm.com/index.php?rid=5643841&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100125 AbstractSoft X‐ray tomography (SXT) is an imaging technique capable of characterizing and quantifying the structural phenotype of cells. In particular, SXT is used to visualize the internal architecture of fully hydrated, intact eukaryotic and prokaryotic cells at high spatial resolution (50 nm or better). Image contrast in SXT is derived from the biochemical composition of the cell, and obtained without the need to use potentially damaging contrast‐enhancing agents, such as heavy metals. The cells are simply cryopreserved prior to imaging, and are therefore imaged in a near‐native state. As a complement to structural imaging by SXT, the same specimen can now be imaged by correlated cryo‐light microscopy. By combining data from these two modalities specific molecules can be local... BioEssays journals http://www.medworm.com/rss/comments.php?id=5643841 Mon, 30 Jan 2012 05:00:00 +0100 5643841 http://www.medworm.com/index.php?rid=5635414&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100090 AbstractBalancing self‐renewal and differentiation of stem cells is an important issue in stem cell and cancer biology. Recently, the Drosophila neuroblast (NB), neural stem cell has emerged as an excellent model for stem cell self‐renewal and tumorigenesis. It is of great interest to understand how defects in the asymmetric division of neural stem cells lead to tumor formation. Here, we review recent advances in asymmetric division and the self‐renewal control of Drosophila NBs. We summarize molecular mechanisms of asymmetric cell division and discuss how the defects in asymmetric division lead to tumor formation. Gain‐of‐function or loss‐of‐function of various proteins in the asymmetric machinery can drive NB overgrowth and tumor formation. These proteins control either the... BioEssays journals http://www.medworm.com/rss/comments.php?id=5635414 Fri, 27 Jan 2012 21:40:09 +0100 5635414 http://www.medworm.com/index.php?rid=5635415&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100135 AbstractHere we elucidate a paradox: how a single chemoattractant‐receptor system in two individuals is used for communication despite the seeming inevitability of self‐excitation. In the filamentous fungus Neurospora crassa, genetically identical cells that produce the same chemoattractant fuse via the homing of individual cell protrusions toward each other. This is achieved via a recently described “ping‐pong” pulsatile communication. Using a generic activator‐inhibitor model of excitable behavior, we demonstrate that the pulse exchange can be fully understood in terms of two excitable systems locked into a stable oscillatory pattern of mutual excitation. The most puzzling properties of this communication are the sudden onset of oscillations with final amplitude, and the abse... BioEssays journals http://www.medworm.com/rss/comments.php?id=5635415 Mon, 23 Jan 2012 05:00:00 +0100 5635415 http://www.medworm.com/index.php?rid=5603992&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100144 AbstractA considerable number of areas of bioscience, including gene and drug discovery, metabolic engineering for the biotechnological improvement of organisms, and the processes of natural and directed evolution, are best viewed in terms of a ‘landscape’ representing a large search space of possible solutions or experiments populated by a considerably smaller number of actual solutions that then emerge. This is what makes these problems ‘hard’, but as such these are to be seen as combinatorial optimisation problems that are best attacked by heuristic methods known from that field. Such landscapes, which may also represent or include multiple objectives, are effectively modelled in silico, with modern active learning algorithms such as those based on Darwinian evolution providing ... BioEssays journals http://www.medworm.com/rss/comments.php?id=5603992 Wed, 18 Jan 2012 22:17:06 +0100 5603992 http://www.medworm.com/index.php?rid=5593047&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201290004 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5593047 Sun, 15 Jan 2012 10:47:53 +0100 5593047 http://www.medworm.com/index.php?rid=5593046&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201290003 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5593046 Sun, 15 Jan 2012 10:47:51 +0100 5593046 http://www.medworm.com/index.php?rid=5593043&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201290001 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5593043 Sun, 15 Jan 2012 10:47:24 +0100 5593043 http://www.medworm.com/index.php?rid=5593042&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201290000 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5593042 Sun, 15 Jan 2012 10:47:22 +0100 5593042 http://www.medworm.com/index.php?rid=5593041&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201290002 The ERK signalling pathway and Huntington's disease. On pages 142–148 Bodai and Marsh discuss the complexity of MAPK signaling in Huntington's disease. In this neurodegenerative disorder, mutant huntingtin protein can both activate or inhibit the MAP kinase ERK depending on the cell type and state. These actions can impact intercellular BDNF‐ and glutamate‐signaling and other events that are transmitted through the ERK kinase pathway. Thus, pathogenic Htt can both activate and/or dampen different branches of the ERK cascade. Understanding the source of this complexity and ERK's key role in the pathogenic response may allow pharmacologic targeting that selectively enhances the protective branches of the ERK response for the treatment of this as yet incurable disease. (Source: BioEssay... BioEssays journals http://www.medworm.com/rss/comments.php?id=5593041 Sun, 15 Jan 2012 10:47:20 +0100 5593041 http://www.medworm.com/index.php?rid=5593033&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100183 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5593033 Sun, 15 Jan 2012 10:46:58 +0100 5593033 http://www.medworm.com/index.php?rid=5593035&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100137 AbstractPriming of lineage‐specific genes in pluripotent embryonic stem cells facilitates rapid and coordinated activation of transcriptional programmes during differentiation. There is growing evidence that pluripotency factors play key roles in priming tissue‐specific genes and in the earliest stages of lineage commitment. As differentiation progresses, pluripotency factors are replaced at some primed genes by related lineage‐specific factors that bind to the same sequences and maintain epigenetic priming until the gene is activated. Polycomb and trithorax group proteins bind many genes in pluripotent cells generating bivalent domains that contain both active and repressive histone modifications. The properties of polycomb proteins suggest that they act as gatekeepers, helping to m... BioEssays journals http://www.medworm.com/rss/comments.php?id=5593035 Fri, 13 Jan 2012 05:00:00 +0100 5593035 http://www.medworm.com/index.php?rid=5593034&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100139 AbstractMany of the most virulent and problematic eukaryotic pathogens have evolved from photosynthetic ancestors, such as apicomplexans, which are responsible for a wide range of diseases including malaria and toxoplasmosis. The primary barrier to understanding the early stages of evolution of these parasites has been the difficulty in finding parasites with closely related free‐living lineages with which to make comparisons. Parasites found throughout the florideophyte red algal lineage, however, provide a unique and powerful model to investigate the genetic origins of a parasitic lifestyle. This is because they share a recent common ancestor with an extant free‐living red algal species and parasitism has independently arisen over 100 times within this group. Here, we synthesize the ... BioEssays journals http://www.medworm.com/rss/comments.php?id=5593034 Fri, 13 Jan 2012 05:00:00 +0100 5593034 http://www.medworm.com/index.php?rid=5593039&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100136 AbstractSignificant progress in the molecular investigation of endogenous bioelectric signals during pattern formation in growing tissues has been enabled by recently developed techniques. Ion flows and voltage gradients produced by ion channels and pumps are key regulators of cell proliferation, migration, and differentiation. Now, instructive roles for bioelectrical gradients in embryogenesis, regeneration, and neoplasm are being revealed through the use of fluorescent voltage reporters and functional experiments using well‐characterized channel mutants. Transmembrane voltage gradients (Vmem) determine anatomical polarity and function as master regulators during appendage regeneration and embryonic left‐right patterning. A state‐of‐the‐art recent study reveals that they can als... BioEssays journals http://www.medworm.com/rss/comments.php?id=5593039 Wed, 11 Jan 2012 05:00:00 +0100 5593039 http://www.medworm.com/index.php?rid=5593038&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100164 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5593038 Wed, 11 Jan 2012 05:00:00 +0100 5593038 http://www.medworm.com/index.php?rid=5593037&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100130 AbstractAdenosine 5′‐triphosphate (ATP) was identified in 1970 as the transmitter responsible for non‐adrenergic, non‐cholinergic neurotransmission in the gut and bladder and the term ‘purinergic’ was coined. Purinergic cotransmission was proposed in 1976 and ATP is now recognized as a cotransmitter in all nerves in the peripheral and central nervous systems. P1 (adenosine) and P2 (ATP) receptors were distinguished in 1978. Cloning of these receptors in the early 1990s was a turning point in the acceptance of the purinergic signalling hypothesis. There are both short‐term purinergic signalling in neurotransmission, neuromodulation and secretion and long‐term (trophic) purinergic signalling of cell proliferation, differentiation and death in development and regeneration. Muc... BioEssays journals http://www.medworm.com/rss/comments.php?id=5593037 Wed, 11 Jan 2012 05:00:00 +0100 5593037 http://www.medworm.com/index.php?rid=5593040&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100149 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5593040 Tue, 10 Jan 2012 05:00:00 +0100 5593040 http://www.medworm.com/index.php?rid=5568851&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100171 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5568851 Thu, 05 Jan 2012 05:00:00 +0100 5568851 http://www.medworm.com/index.php?rid=5568852&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100102 AbstractThe activity of Wnt and Notch signalling is central to many cell fate decisions during development and to the maintenance and differentiation of stem cell populations in homeostasis. While classical views refer to these pathways as independent signal transduction devices that co‐operate in different systems, recent work has revealed intricate connections between their components. These observations suggest that rather than operating as two separate pathways, elements of Wnt and Notch signalling configure an integrated molecular device whose main function is to regulate transitions between cell states in development and homeostasis. Here, we propose a general framework for the structure and function of the interactions between these signalling systems that is focused on the notion... BioEssays journals http://www.medworm.com/rss/comments.php?id=5568852 Tue, 03 Jan 2012 05:00:00 +0100 5568852 http://www.medworm.com/index.php?rid=5568850&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100160 AbstractCo‐option of the eye developmental gene regulatory network may have led to the appearance of novel functional traits on the wings of flies and butterflies. The first trait is a recently described wing organ in a species of extinct midge resembling the outer layers of the midge's own compound eye. The second trait is red pigment patches on Heliconius butterfly wings connected to the expression of an eye selector gene, optix. These examples, as well as others, are discussed regarding the type of empirical evidence and burden of proof that have been used to infer gene network co‐option underlying the origin of novel traits. A conceptual framework describing increasing confidence in inference of network co‐option is proposed. Novel research directions to facilitate inference of n... BioEssays journals http://www.medworm.com/rss/comments.php?id=5568850 Sun, 01 Jan 2012 05:00:00 +0100 5568850 http://www.medworm.com/index.php?rid=5520358&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190076 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5520358 Tue, 20 Dec 2011 09:34:20 +0100 5520358 http://www.medworm.com/index.php?rid=5520357&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190075 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5520357 Tue, 20 Dec 2011 09:34:19 +0100 5520357 http://www.medworm.com/index.php?rid=5520356&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190073 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5520356 Tue, 20 Dec 2011 09:34:03 +0100 5520356 http://www.medworm.com/index.php?rid=5520355&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190072 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5520355 Tue, 20 Dec 2011 09:34:02 +0100 5520355 http://www.medworm.com/index.php?rid=5520354&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190071 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5520354 Tue, 20 Dec 2011 09:34:01 +0100 5520354 http://www.medworm.com/index.php?rid=5520353&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190074 Early eye development: Formation of the optic cup. Eye development is a complex process involving evagination and invagination processes of the retinal epithelium to form a double‐walled cup structure. On pages 17–25 Eiraku et al. introduce a new model explaining the tissue dynamics that enable the spontaneous invagination of the neural retina. This “relaxation‐expansion” model involves the following consecutive local rules: relaxation in the neural retina, apical constriction at the boundary epithelium between the neural retina and retinal pigment epithelium domains (hinge) and tangential expansion in the neural retina. Computer simulation of this model successfully recapitulates optic‐cup morphogenesis.Cover by M. Eiraku, T. Adachi and Y. Sasai. (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5520353 Tue, 20 Dec 2011 09:33:59 +0100 5520353 http://www.medworm.com/index.php?rid=5520352&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100141 AbstractThe haploid male germ cell differentiation program controls essential steps of male gametogenesis and relies partly on a significant number of sex chromosome‐linked genes. These genes need to escape chromosome‐wide transcriptional repression of sex chromosomes, which occurs during meiosis and is largely maintained in post‐meiotic cells. A newly discovered histone lysine modification, crotonylation (Kcr), marks X/Y‐linked genes that are active in post‐meiotic male germ cells. Histone Kcr, by conferring resistance to transcriptional repressors, could be a dominant element in maintaining these genes active in the globally repressive environment of haploid cell sex chromosomes. Furthermore, the same mark was found associated with post‐meiotically activated genes on autosome... BioEssays journals http://www.medworm.com/rss/comments.php?id=5520352 Tue, 20 Dec 2011 09:33:44 +0100 5520352 http://www.medworm.com/index.php?rid=5483093&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100152 AbstractHere I discuss findings that suggest a universal mechanism for proteins (and RNA) to recognize and interact with various binding partners by selectively binding to different conformations that pre‐exist in the free protein's conformational ensemble. The tandem RNA recognition motif domains of splicing factor U2AF65 fluctuate in solution between a predominately closed conformation in which the RNA binding site of one of the domains is blocked, and a lowly populated open conformation in which both RNA binding pockets are accessible. RNA binding to U2AF65 may thus occur through the weakly populated open conformation, and the binding interaction stabilizes the open conformation. The conformational diversity observed in U2AF65 might also facilitate binding to diverse RNA sequences as ... BioEssays journals http://www.medworm.com/rss/comments.php?id=5483093 Thu, 01 Dec 2011 05:00:00 +0100 5483093 http://www.medworm.com/index.php?rid=5465175&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100110 AbstractAnalyses of environmental DNAs have provided tantalizing evidence for “rozellida” or “cryptomycota”, a clade of mostly undescribed and deeply diverging aquatic fungi. Here, we put cryptomycota into perspective through consideration of Rozella, the only clade member growing in culture. This is timely on account of the publication in Nature of the first images of uncultured cryptomycota from environmental filtrates, where molecular probes revealed non‐motile cyst‐like structures and motile spores, all lacking typical fungal chitinous cell walls. Current studies of Rozella can complement these fragmentary observations from environmental samples. Rozella has a fungal‐specific chitin synthase and its resting sporangia have walls that appear to contain chitin. Cryptomycota,... BioEssays journals http://www.medworm.com/rss/comments.php?id=5465175 Thu, 01 Dec 2011 05:00:00 +0100 5465175 http://www.medworm.com/index.php?rid=5447629&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100165 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5447629 Sat, 26 Nov 2011 10:51:15 +0100 5447629 http://www.medworm.com/index.php?rid=5437249&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100049 AbstractCancer viewed as a programmed, evolutionarily conserved life‐form, rather than just a random series of disease‐causing mutations, answers the rarely asked question of what the cancer cell is for, provides meaning for its otherwise mysterious suite of attributes, and encourages a different type of thinking about treatment. The broad but consistent spectrum of traits, well‐recognized in all aggressive cancers, group naturally into three categories: taxonomy (“phylogenation”), atavism (“re‐primitivization”) and robustness (“adaptive resilience”). The parsimonious explanation is not convergent evolution, but the release of an highly conserved survival program, honed by the exigencies of the Pre‐Cambrian, to which the cancer cell seems better adapted; and which is ... BioEssays journals http://www.medworm.com/rss/comments.php?id=5437249 Wed, 23 Nov 2011 09:49:01 +0100 5437249 http://www.medworm.com/index.php?rid=5428034&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100145 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5428034 Sun, 20 Nov 2011 10:04:38 +0100 5428034 http://www.medworm.com/index.php?rid=5428035&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100031 AbstractThe Neo‐Darwinian concept of natural selection is plausible when one assumes a straightforward causation of phenotype by genotype. However, such simple 1:1 mapping must now give place to the modern concepts of gene regulatory networks and gene expression noise. Both can, in the absence of genetic mutations, jointly generate a diversity of inheritable randomly occupied phenotypic states that could also serve as a substrate for natural selection. This form of epigenetic dynamics challenges Neo‐Darwinism. It needs to incorporate the non‐linear, stochastic dynamics of gene networks. A first step is to consider the mathematical correspondence between gene regulatory networks and Waddington's metaphoric ‘epigenetic landscape’, which actually represents the quasi‐potential fun... BioEssays journals http://www.medworm.com/rss/comments.php?id=5428035 Fri, 18 Nov 2011 05:00:00 +0100 5428035 http://www.medworm.com/index.php?rid=5417632&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190070 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5417632 Fri, 18 Nov 2011 00:29:56 +0100 5417632 http://www.medworm.com/index.php?rid=5417631&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190068 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5417631 Fri, 18 Nov 2011 00:29:55 +0100 5417631 http://www.medworm.com/index.php?rid=5417630&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190066 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5417630 Fri, 18 Nov 2011 00:29:54 +0100 5417630 http://www.medworm.com/index.php?rid=5417629&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190065 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5417629 Fri, 18 Nov 2011 00:29:39 +0100 5417629 http://www.medworm.com/index.php?rid=5417628&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190064 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5417628 Fri, 18 Nov 2011 00:29:38 +0100 5417628 http://www.medworm.com/index.php?rid=5417627&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190063 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5417627 Fri, 18 Nov 2011 00:29:37 +0100 5417627 http://www.medworm.com/index.php?rid=5417626&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190069 The Hox gene fushi tarazu (ftz) functions as a pair‐rule segmentation gene in Drosophila. In contrast, Ftz protein from a beetle (Tc‐Ftz) retains homeotic potential, indicated by its ability to transform antenna (upper left) to leg (lower right) and to repress Homothorax expression (red) when expressed in Drosophila, observed as loss of overlap between GFP, which marks Tc‐Ftz expression, and Homothorax expression (upper right). Heffer et al. review the evidence that ftz evolved from a traditional Hox gene with homeotic potential to a gene with exclusive pair‐rule segmentation function in Drosophila. The authors correlate Ftz functional evolution with the presence and absence of distinct co‐factor interaction domains, necessary for either homeotic or segmentation function.Backcove... BioEssays journals http://www.medworm.com/rss/comments.php?id=5417626 Fri, 18 Nov 2011 00:29:36 +0100 5417626 http://www.medworm.com/index.php?rid=5417619&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100104 AbstractInflamm‐aging is a relatively new terminology used to describe the age‐related increase in the systemic pro‐inflammatory status of humans. Here, we represent inflamm‐aging as a breakdown in the multi‐shell cytokine network, in which stem cells and stromal fibroblasts (referred to as the stem cell niche) become pro‐inflammatory cytokine over‐expressing cells due to the accumulation of DNA damage. Inflamm‐aging self‐propagates owing to the capability of pro‐inflammatory cytokines to ignite the DNA‐damage response in other cells surrounding DNA‐damaged cells. Macrophages, the major cellular player in inflamm‐aging, amplify the phenomenon, by broadcasting pro‐inflammatory signals at both local and systemic levels. On the basis of this, we propose that inflam... BioEssays journals http://www.medworm.com/rss/comments.php?id=5417619 Fri, 18 Nov 2011 00:29:15 +0100 5417619 http://www.medworm.com/index.php?rid=5417623&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100116 AbstractActivating the ERK pathway (extracellular signal‐regulated kinase pathway) has proven beneficial in several models of Huntington's disease (HD), and drugs that are protective in HD models have recently been found to activate ERK. Thus, the ERK cascade may be a potential target for therapeutic intervention in this currently untreatable disorder. HD is caused by an expanded polyglutamine repeat in the huntingtin (Htt) protein that actuates a diverse set of pathogenic mechanisms. In response to mutant Htt, ERK is activated and directs a protective transcriptional response and inhibits caspase activation. Paradoxically, Htt also interferes with several signaling events of the ERK pathway. Mutant Htt compromises the ERK‐dependent transcriptional response to corticostriatal BDNF sign... BioEssays journals http://www.medworm.com/rss/comments.php?id=5417623 Wed, 16 Nov 2011 05:00:00 +0100 5417623 http://www.medworm.com/index.php?rid=5417622&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100127 AbstractWe have discovered that a single sperm protein, phospholipase C‐zeta (PLCζ), can stimulate intracellular Ca2+ signalling in the unfertilized oocyte (‘egg’) culminating in the initiation of embryonic development. Upon fertilization by a spermatozoon, the earliest observed signalling event in the dormant egg is a large, transient increase in free Ca2+ concentration. The fertilized egg responds to the intracellular Ca2+ rise by completing meiosis. In mammalian eggs, the Ca2+ signal is delivered as a train of long‐lasting cytoplasmic Ca2+ oscillations that begin soon after gamete fusion and persist beyond the completion of meiosis. Sperm PLCζ effects Ca2+ release from egg intracellular stores by hydrolyzing the membrane lipid PIP2 and consequent stimulation of the inositol 1,... BioEssays journals http://www.medworm.com/rss/comments.php?id=5417622 Wed, 16 Nov 2011 05:00:00 +0100 5417622 http://www.medworm.com/index.php?rid=5417621&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100126 AbstractCellular identity and its response to external or internal signalling variations are encoded in a cell's genome as regulatory information. The genomic regions that specify this type of information are highly variable and degenerated in their sequence determinants, as it is becoming increasingly evident through the application of genome‐scale methods to study gene expression. Here, we speculate that the same scenario applies to the regulatory regions controlling where DNA replication starts in the metazoan genome. We propose that replication origins cannot be defined as unique genomic features, but rather that DNA synthesis initiates opportunistically from accessible DNA sites, making cells highly robust and adaptable to environmental or developmental changes. (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5417621 Wed, 16 Nov 2011 05:00:00 +0100 5417621 http://www.medworm.com/index.php?rid=5417620&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100122 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5417620 Wed, 16 Nov 2011 05:00:00 +0100 5417620 http://www.medworm.com/index.php?rid=5417624&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100121 AbstractThis paper, in the form of a frequently asked questions page (FAQ), addresses outstanding questions about “shadow enhancers”, quasi‐redundant cis‐regulatory elements, and their proposed roles in transcriptional control. Questions include: What exactly are shadow enhancers? How many genes have shadow/redundant/distributed enhancers? How redundant are these elements? What is the function of distributed enhancers? How modular are enhancers? Is it useful to study a single enhancer in isolation? In addition, a revised definition of “shadow enhancers” is proposed, and possible mechanisms of shadow enhancer function and evolution are discussed. (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5417624 Tue, 15 Nov 2011 05:00:00 +0100 5417624 http://www.medworm.com/index.php?rid=5396802&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100099 We present three models for the evolution of SD by genetic assimilation, based on recent advances in our understanding of the mechanisms of endometrial differentiation and implantation. Testing these models will ultimately shed light on the evolutionary significance of menstruation, as well as on the etiology of human reproductive disorders like endometriosis and recurrent pregnancy loss. (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5396802 Mon, 07 Nov 2011 05:00:00 +0100 5396802 http://www.medworm.com/index.php?rid=5375321&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100132 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5375321 Wed, 02 Nov 2011 04:00:00 +0100 5375321 http://www.medworm.com/index.php?rid=5375320&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100094 AbstractThe fate of cells arrested in mitosis by antimitotic compounds is complex but is influenced by competition between pathways promoting cell death and pathways promoting mitotic exit. As components of both of these pathways are regulated by Cdc20‐dependent degradation, I hypothesize that variations in Cdc20 protein levels, rather than mutations in checkpoint genes, could affect cell fate during prolonged mitotic arrest. This hypothesis is supported by experiments where manipulation of Cdc20 levels affects the response to antimitotic compounds. The observed differences in Cdc20 levels between cell lines likely reflects differences in the rate of synthesis or degradation of the protein; therefore, understanding these pathways at a molecular level could pave the way for modulating the... BioEssays journals http://www.medworm.com/rss/comments.php?id=5375320 Wed, 02 Nov 2011 04:00:00 +0100 5375320 http://www.medworm.com/index.php?rid=5375319&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100134 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5375319 Wed, 02 Nov 2011 04:00:00 +0100 5375319 http://www.medworm.com/index.php?rid=5375318&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100146 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5375318 Wed, 02 Nov 2011 04:00:00 +0100 5375318 http://www.medworm.com/index.php?rid=5375317&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100158 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5375317 Wed, 02 Nov 2011 04:00:00 +0100 5375317 http://www.medworm.com/index.php?rid=5396801&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100156 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5396801 Tue, 01 Nov 2011 04:00:00 +0100 5396801 http://www.medworm.com/index.php?rid=5375316&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100070 AbstractThe generation of complex organ structures such as the eye requires the intricate orchestration of multiple cellular interactions. In this paper, early retinal development is discussed with respect to the structure formation of the optic cup. Although recent studies have elucidated molecular mechanisms of retinal differentiation, little is known about how the unique shape of the optic cup is determined. A recent report has demonstrated that optic‐cup morphogenesis spontaneously occurs in three‐dimensional stem‐cell culture without external forces, indicating a latent intrinsic order to generate the structure. Based on this self‐organizing phenomenon, we introduce the “relaxation‐expansion” model to mechanically interpret the tissue dynamics that enable the spontaneous... BioEssays journals http://www.medworm.com/rss/comments.php?id=5375316 Tue, 01 Nov 2011 04:00:00 +0100 5375316 http://www.medworm.com/index.php?rid=5375323&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100147 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5375323 Fri, 28 Oct 2011 04:00:00 +0100 5375323 http://www.medworm.com/index.php?rid=5375322&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100071 AbstractConsiderable hope surrounds the use of disease‐specific pluripotent stem cells to generate models of human disease allowing exploration of pathological mechanisms and search for new treatments. Disease‐specific human embryonic stem cells were the first to provide a useful source for studying certain disease states. The recent demonstration that human somatic cells, derived from readily accessible tissue such as skin or blood, can be converted to embryonic‐like induced pluripotent stem cells (hiPSCs) has opened new perspectives for modelling and understanding a larger number of human pathologies. In this review, we examine the opportunities and challenges for the use of disease‐specific pluripotent stem cells in disease modelling and drug screening. Progress in these areas w... BioEssays journals http://www.medworm.com/rss/comments.php?id=5375322 Fri, 28 Oct 2011 04:00:00 +0100 5375322 http://www.medworm.com/index.php?rid=5355389&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100089 AbstractDeveloping cells acquire mature fates in part by selective (i.e. qualitatively different) expression of a few cell‐specific genes. However, all cells share the same basic repertoire of molecular and subcellular building blocks. Therefore, cells must also specialize according to quantitative differences in cell‐specific distributions of those common molecular resources. Here we propose the novel hypothesis that evolutionarily‐conserved transcription factors called scaling factors (SFs) regulate quantitative differences among mature cell types. SFs: (1) are induced during late stages of cell maturation; (2) are dedicated to specific subcellular domains; and, thus, (3) allow cells to emphasize specific subcellular features. We identify candidate SFs and discuss one in detail: MI... BioEssays journals http://www.medworm.com/rss/comments.php?id=5355389 Fri, 28 Oct 2011 02:36:39 +0100 5355389 http://www.medworm.com/index.php?rid=5355390&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100107 AbstractThe PRDM family has recently spawned considerable interest as it has been implicated in fundamental aspects of cellular differentiation and exhibits expanding ties to human diseases. The PRDMs belong to the SET domain family of histone methyltransferases, however, enzymatic activity has been determined for only few PRDMs suggesting that they act by recruiting co‐factors or, more speculatively, confer methylation of non‐histone targets. Several PRDM family members are deregulated in human diseases, most prominently in hematological malignancies and solid cancers, where they can act as both tumor suppressors or drivers of oncogenic processes. The molecular mechanisms have been delineated for only few PRDMs and little is known about functional redundancy within the family. Future ... BioEssays journals http://www.medworm.com/rss/comments.php?id=5355390 Wed, 26 Oct 2011 04:00:00 +0100 5355390 http://www.medworm.com/index.php?rid=5330641&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190060 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5330641 Wed, 19 Oct 2011 20:39:01 +0100 5330641 http://www.medworm.com/index.php?rid=5330640&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190059 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5330640 Wed, 19 Oct 2011 20:39:00 +0100 5330640 http://www.medworm.com/index.php?rid=5330639&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100051 AbstractMany conserved eukaryotic traits, including apoptosis, two sexes, speciation and ageing, can be causally linked to a bioenergetic requirement for mitochondrial genes. Mitochondrial genes encode proteins involved in cell respiration, which interact closely with proteins encoded by nuclear genes. Functional respiration requires the coadaptation of mitochondrial and nuclear genes, despite divergent tempi and modes of evolution. Free‐radical signals emerge directly from the biophysics of mosaic respiratory chains encoded by two genomes prone to mismatch, with apoptosis being the default penalty for compromised respiration. Selection for genomic matching is facilitated by two sexes, and optimizes fitness, adaptability and fertility in youth. Mismatches cause infertility, low fitness, ... BioEssays journals http://www.medworm.com/rss/comments.php?id=5330639 Wed, 19 Oct 2011 20:38:56 +0100 5330639 http://www.medworm.com/index.php?rid=5330638&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190057 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5330638 Wed, 19 Oct 2011 20:38:43 +0100 5330638 http://www.medworm.com/index.php?rid=5330637&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190056 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5330637 Wed, 19 Oct 2011 20:38:41 +0100 5330637 http://www.medworm.com/index.php?rid=5330636&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190055 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5330636 Wed, 19 Oct 2011 20:38:40 +0100 5330636 http://www.medworm.com/index.php?rid=5330635&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190061 FBW7 in cancer drug resistance. The occurrence of resistance to chemotherapeutic agents constitutes a major problem in cancer treatment. In their article on pages 851‐859, Wang et al. elucidate the role of the F‐box and WD repeat domain‐containing 7 (FBW7) tumor suppressor in this process. On one hand, FBW7‐deficient cells are addicted to the elevated levels of the Mcl‐1 pro‐survival factor, rendering these cells more sensitive to the chemotherapeutic drug sorafenib. On the other hand, in the absence of this protein, taxol‐ and vincristineinduced cell death is inhibited. Furthermore, inhibition of tumor growth by ABT‐737 and gamma secretase inhibitor (GSI) is impaired. Because of its central role in cancer drug resistance, targeting of FBW7 may open a new therapeutic window... BioEssays journals http://www.medworm.com/rss/comments.php?id=5330635 Wed, 19 Oct 2011 20:38:39 +0100 5330635 http://www.medworm.com/index.php?rid=5330627&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100143 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5330627 Wed, 19 Oct 2011 20:38:22 +0100 5330627 http://www.medworm.com/index.php?rid=5330631&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100138 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5330631 Tue, 18 Oct 2011 04:00:00 +0100 5330631 http://www.medworm.com/index.php?rid=5330630&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100091 AbstractIn many species the mutation rate is higher in males than in females, a phenomenon denoted as male mutation bias. This is often observed in animals where males produce many more sperm than females produce eggs, and is thought to result from differences in the number of replication‐associated mutations accumulated in each sex. Thus, studies of male mutation bias have the capacity to reveal information about the replication‐dependent or replication‐independent nature of different mutations. The availability of whole genome sequences for many species, as well as for multiple individuals within a species, has opened the door to studying factors, both sequence‐specific and those acting on the genome globally, that affect differences in mutation rates between males and females. H... BioEssays journals http://www.medworm.com/rss/comments.php?id=5330630 Tue, 18 Oct 2011 04:00:00 +0100 5330630 http://www.medworm.com/index.php?rid=5330629&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100123 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5330629 Tue, 18 Oct 2011 04:00:00 +0100 5330629 http://www.medworm.com/index.php?rid=5330628&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100082 AbstractInvertebrate genetic models with their tractable neuromuscular systems are effective vehicles for the study of human nerve and muscle disorders. This is exemplified by insights made into spinal muscular atrophy (SMA) using the fruit fly Drosophila melanogaster and the nematode worm Caenorhabditis elegans. For speed and economy, these invertebrates offer convenient, whole‐organism platforms for genetic screening as well as RNA interference (RNAi) and chemical library screens, permitting the rapid testing of hypotheses related to disease mechanisms and the exploration of new therapeutic routes and drug candidates. Here, we discuss recent developments encompassing synaptic physiology, RNA processing, and screening of compound and genome‐scale RNAi libraries, showcasing the importa... BioEssays journals http://www.medworm.com/rss/comments.php?id=5330628 Tue, 18 Oct 2011 04:00:00 +0100 5330628 http://www.medworm.com/index.php?rid=5330632&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100109 AbstractMultigene delivery and expression systems are emerging as key technologies for many applications in contemporary biology. We have developed new methods for multigene delivery and expression in eukaryotic hosts for a variety of applications, including production of protein complexes for structural biology and drug development, provision of multicomponent protein biologics, and cell‐based assays. We implemented tandem recombineering to facilitate rapid generation of multicomponent gene expression constructs for efficient transformation of mammalian cells, resulting in homogenous cell populations. Analysis of multiple parameters in living cells may require co‐expression of fluorescently tagged sensors simultaneously in a single cell, at defined and ideally controlled ratios. Our m... BioEssays journals http://www.medworm.com/rss/comments.php?id=5330632 Mon, 17 Oct 2011 04:00:00 +0100 5330632 http://www.medworm.com/index.php?rid=5321510&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100124 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5321510 Fri, 14 Oct 2011 04:00:00 +0100 5321510 http://www.medworm.com/index.php?rid=5292908&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100117 AbstractEditor's suggested further reading in BioEssays: Fields and field cancerization: The preneoplastic origins of cancer Abstract (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5292908 Wed, 05 Oct 2011 04:00:00 +0100 5292908 http://www.medworm.com/index.php?rid=5321509&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100096 AbstractThe study of alternative genetic systems and mixed modes of reproduction, whereby sexual and asexual reproduction is combined within the same lifecycle, is of fundamental importance as they may shed light on classical evolutionary issues, such as the paradox of sex. Recently, several such cases were discovered in social insects. A closer examination of these systems has revealed many amazing facts, including the mixed use of asexual and sexual reproduction for the production of new queens and workers, males that can clone themselves and the routine use of incest without deleterious genetic consequences. In addition, in several species, remarkable cases of asexually reproducing socially parasitic worker lineages have been discovered. The study of these unusual systems promises to pr... BioEssays journals http://www.medworm.com/rss/comments.php?id=5321509 Sat, 01 Oct 2011 04:00:00 +0100 5321509 http://www.medworm.com/index.php?rid=5292907&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100112 AbstractIn a recent paper, Merabet and Hudry discuss models explaining the functional evolution of fushi tarazu (ftz) from an ancestral homeotic to a pair‐rule segmentation gene in Drosophila. As most of the experimental work underlying these models comes from our research, we wish to reply to Merabet and Hudry providing an explanation of the experimental approaches and logical framework underlying them. We review experimental data that support our hypotheses and discuss misconceptions in the literature. We emphasize that the change in ftz function required changes in both expression pattern and protein function and review the evidence that these functional changes involved a switch in cofactor‐interaction motifs during arthropod radiations. While agreeing with Merabet and Hudry that p... BioEssays journals http://www.medworm.com/rss/comments.php?id=5292907 Sat, 01 Oct 2011 04:00:00 +0100 5292907 http://www.medworm.com/index.php?rid=5268624&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100075 AbstractNext‐generation sequencing (NGS) technologies have revolutionised the analysis of genomic structural variants (SVs), providing significant insights into SV de novo formation based on analyses of rearrangement breakpoint junctions. The short DNA reads generated by NGS, however, have also created novel obstacles by biasing the ascertainment of SVs, an aspect that we refer to as the ‘short‐read dilemma’. For example, recent studies have found that SVs are often complex, with SV formation generating large numbers of breakpoints in a single event (multi‐breakpoint SVs) or structurally polymorphic loci having multiple allelic states (multi‐allelic SVs). This complexity may be obscured in short reads, unless the data is analysed and interpreted within its wider genomic context... BioEssays journals http://www.medworm.com/rss/comments.php?id=5268624 Fri, 30 Sep 2011 11:48:39 +0100 5268624 http://www.medworm.com/index.php?rid=5268626&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100047 AbstractIn this paper, we hypothesize that X chromosome‐associated mechanisms, which affect X‐linked genes and are behind the immunological advantage of females, may also affect X‐linked microRNAs. The human X chromosome contains 10% of all microRNAs detected so far in the human genome. Although the role of most of them has not yet been described, several X chromosome‐located microRNAs have important functions in immunity and cancer. We therefore provide a detailed map of all described microRNAs located on human and mouse X chromosomes, and highlight the ones involved in immune functions and oncogenesis. The unique mode of inheritance of the X chromosome is ultimately the cause of the immune disadvantage of males and the enhanced survival of females following immunological challeng... BioEssays journals http://www.medworm.com/rss/comments.php?id=5268626 Wed, 28 Sep 2011 04:00:00 +0100 5268626 http://www.medworm.com/index.php?rid=5268625&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100128 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5268625 Wed, 28 Sep 2011 04:00:00 +0100 5268625 http://www.medworm.com/index.php?rid=5233440&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190054 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5233440 Tue, 20 Sep 2011 00:42:53 +0100 5233440 http://www.medworm.com/index.php?rid=5233439&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190053 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5233439 Tue, 20 Sep 2011 00:42:52 +0100 5233439 http://www.medworm.com/index.php?rid=5233438&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190051 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5233438 Tue, 20 Sep 2011 00:42:51 +0100 5233438 http://www.medworm.com/index.php?rid=5233437&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190050 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5233437 Tue, 20 Sep 2011 00:42:38 +0100 5233437 http://www.medworm.com/index.php?rid=5233436&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190049 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5233436 Tue, 20 Sep 2011 00:42:36 +0100 5233436 http://www.medworm.com/index.php?rid=5233435&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190052 ‘Tug of war’ between cells: Cell‐cell junction development depends on the forces applied. The cover image shows adherens junctions (magenta) with actin filaments (green) in an NRK fibroblast sheet. This type of adherens junction has an actin filament bundle oriented perpendicularly to the plasma membrane. Because actin bundles on both sides of the adherens junction are oriented along a straight line, it is obvious that both actin bundles are pulling each other and that adherens junctions are responsible for transmitting forces between cells. Recent studies reported that structure/function of adherens junctions/cadherin‐mediated cell adhesions changes according to the forces applied to them. In this issue (pages 732–736) Shigenobu Yonemura gives an overview of mechanotransduction ... BioEssays journals http://www.medworm.com/rss/comments.php?id=5233435 Tue, 20 Sep 2011 00:42:35 +0100 5233435 http://www.medworm.com/index.php?rid=5233433&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100084 AbstractCommon themes are emerging in the molecular mechanisms of long non‐coding RNA‐mediated gene repression. Long non‐coding RNAs (lncRNAs) participate in targeted gene silencing through chromatin remodelling, nuclear reorganisation, formation of a silencing domain and precise control over the entry of genes into silent compartments. The similarities suggest that these are fundamental processes of transcription regulation governed by lncRNAs. These findings have paved the way for analogous investigations on other lncRNAs and chromatin remodelling enzymes. Here we discuss these common mechanisms and provide our view on other molecules that warrant similar investigations. We also present our concepts on the possible mechanisms that may facilitate the exit of genes from the silencing... BioEssays journals http://www.medworm.com/rss/comments.php?id=5233433 Tue, 20 Sep 2011 00:42:22 +0100 5233433 http://www.medworm.com/index.php?rid=5233434&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100100 AbstractWhen cells are starved of their substrate, many nutrient transporters are induced. These undergo rapid endocytosis and redirection of their intracellular trafficking when their substrate becomes available again. The discovery that some of these transporters also act as receptors, or transceptors, suggests that at least part of the sophisticated controls governing the trafficking of these proteins has to do with their signaling function rather than with control of transport. In yeast, the general amino acid permease Gap1 mediates signaling to the protein kinase A pathway. Its endocytic internalization and intracellular trafficking are subject to amino acid control. Other nutrient transceptors controlling this signal transduction pathway appear to be subject to similar trafficking re... BioEssays journals http://www.medworm.com/rss/comments.php?id=5233434 Tue, 13 Sep 2011 04:00:00 +0100 5233434 http://www.medworm.com/index.php?rid=5204165&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100073 AbstractWe have developed a first generation tool for the unbiased identification and characterization of human pluripotent stem cells, termed PluriTest. This assay utilizes all the information contained on a microarray and abandons the conventional stem cell marker concept. Stem cells are defined by the ability to replenish themselves and to differentiate into more mature cell types. As differentiation potential is a property that cannot be directly proven in the stem cell state, biologists have to rely on correlative measurements in stem cells associated with differentiation potential. Unfortunately, most, if not all, of those markers are only valid within narrow limits of specific experimental systems. Microarray technologies and recently next‐generation sequencing have revolutionized... BioEssays journals http://www.medworm.com/rss/comments.php?id=5204165 Thu, 08 Sep 2011 04:00:00 +0100 5204165 http://www.medworm.com/index.php?rid=5204164&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100115 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5204164 Thu, 01 Sep 2011 04:00:00 +0100 5204164 http://www.medworm.com/index.php?rid=5194788&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100103 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5194788 Wed, 31 Aug 2011 23:00:00 +0100 5194788 http://www.medworm.com/index.php?rid=5179213&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100101 AbstractChemotherapy is an important therapeutic approach for cancer treatment. However, drug resistance is an obstacle that often impairs the successful use of chemotherapies. Therefore, overcoming drug resistance would lead to better therapeutic outcomes for cancer patients. Recently, studies by our own and other groups have demonstrated that there is an intimate correlation between the loss of the F‐box and WD repeat domain‐containing 7 (FBW7) tumor suppressor and the incurring drug resistance. While loss of FBW7 sensitizes cancer cells to certain drugs, FBW7‐/‐ cells are more resistant to other types of chemotherapies. FBW7 exerts its tumor suppressor function by promoting the degradation of various oncoproteins that regulate many cellular processes, including cell cycle progre... BioEssays journals http://www.medworm.com/rss/comments.php?id=5179213 Wed, 31 Aug 2011 03:17:21 +0100 5179213 http://www.medworm.com/index.php?rid=5173935&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100093 AbstractProtection against bacterial and viral pathogens by antibodies has always been thought to end at the cell surface. Once inside the cell, a pathogen was understood to be safe from humoral immunity. However, it has now been found that antibodies can routinely enter cells attached to viral particles and mediate an intracellular immune response. Antibody‐coated virions are detected inside the cell by means of an intracellular antibody receptor, TRIM21, which directs their degradation by recruitment of the ubiquitin‐proteasome system. In this article we assess how this discovery alters our view of the way in which antibodies neutralise viral infection. We also consider the antiviral function of TRIM21 in the context of its other reported roles in immune signalling and autoimmunity. ... BioEssays journals http://www.medworm.com/rss/comments.php?id=5173935 Tue, 30 Aug 2011 02:40:59 +0100 5173935 http://www.medworm.com/index.php?rid=5168875&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100095 AbstractFacultative bacterial endosymbionts can transfer horizontally among lineages of their arthropod hosts, providing the recipient with a suite of traits that can lead to rapid evolutionary response, as has been recently demonstrated. But how common is symbiont‐driven evolution? Evidence suggests that successful symbiont transfers are most likely within a species or among closely related species, although more distant transfers have occurred over evolutionary history. Symbiont‐driven evolution need not be a function of a recent horizontal transfer, however. Many endosymbionts infect only a small proportion of a host population, but could quickly increase in frequency under favorable selection regimes. Some host species appear to accumulate a diversity of facultative endosymbionts, ... BioEssays journals http://www.medworm.com/rss/comments.php?id=5168875 Sun, 28 Aug 2011 01:38:08 +0100 5168875 http://www.medworm.com/index.php?rid=5155616&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100023 AbstractPlanar cell polarity (PCP), the alignment of cells within 2D tissue planes, involves a set of core molecular regulators highly conserved between animals and cell types. These include the transmembrane proteins Frizzled (Fz) and VanGogh and the cytoplasmic regulators Dishevelled (Dsh) and Prickle. It is widely accepted that this core forms part of a ‘PCP pathway’ for signal transduction, which can affect cell morphology through activation of an evolutionary ancient regulatory module involving Rho family GTPases and Myosin II, and/or the JNK kinase cascade. We have re‐examined the evidence for interactions between the proposed PCP pathway components, and question the placing of the cell morphology regulators in the same pathway as the PCP core. While Fz and Dsh are clearly invo... BioEssays journals http://www.medworm.com/rss/comments.php?id=5155616 Thu, 25 Aug 2011 07:38:16 +0100 5155616 http://www.medworm.com/index.php?rid=5155618&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100045 AbstractPlanctomycetes, Verrucomicrobia and Chlamydia are prokaryotic phyla, sometimes grouped together as the PVC superphylum of eubacteria. Some PVC species possess interesting attributes, in particular, internal membranes that superficially resemble eukaryotic endomembranes. Some biologists now claim that PVC bacteria are nucleus‐bearing prokaryotes and are considered evolutionary intermediates in the transition from prokaryote to eukaryote. PVC prokaryotes do not possess a nucleus and are not intermediates in the prokaryote‐to‐eukaryote transition. Here we summarise the evidence that shows why all of the PVC traits that are currently cited as evidence for aspiring eukaryoticity are either analogous (the result of convergent evolution), not homologous, to eukaryotic traits; or els... BioEssays journals http://www.medworm.com/rss/comments.php?id=5155618 Sun, 21 Aug 2011 23:00:00 +0100 5155618 http://www.medworm.com/index.php?rid=5155617&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100083 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5155617 Sun, 21 Aug 2011 23:00:00 +0100 5155617 http://www.medworm.com/index.php?rid=5155619&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100062 AbstractThe increasing number of sequenced genomes has prompted the development of several automated orthology prediction methods. Tests to evaluate the accuracy of predictions and to explore biases caused by biological and technical factors are therefore required. We used 70 manually curated families to analyze the performance of five public methods in Metazoa. We analyzed the strengths and weaknesses of the methods and quantified the impact of biological and technical challenges. From the latter part of the analysis, genome annotation emerged as the largest single influencer, affecting up to 30% of the performance. Generally, most methods did well in assigning orthologous group but they failed to assign the exact number of genes for half of the groups. The publicly available benchmark se... BioEssays journals http://www.medworm.com/rss/comments.php?id=5155619 Thu, 18 Aug 2011 23:00:00 +0100 5155619 http://www.medworm.com/index.php?rid=5137813&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100076 AbstractThe demonstration that dendritic cell (DC)‐derived exosomes can be exploited for targeted RNAi delivery to the brain after systemic injection provides the first proof‐of‐concept for the potential of these naturally occurring vesicles as vehicles of drug delivery. As well as being amenable to existing in vivo targeting strategies already in use for viruses and liposomes, this novel approach offers the added advantages of in vivo safety and low immunogenicity. Fulfilment of the potential of exosome delivery methods warrants a better understanding of their biology, as well as the development of novel production, characterisation, targeting and cargo‐loading nanotechnologies. Ultimately, exosome‐mediated drug delivery promises to overcome important challenges in the field of ... BioEssays journals http://www.medworm.com/rss/comments.php?id=5137813 Wed, 17 Aug 2011 17:06:41 +0100 5137813 http://www.medworm.com/index.php?rid=5137817&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100105 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5137817 Tue, 16 Aug 2011 23:00:00 +0100 5137817 http://www.medworm.com/index.php?rid=5137815&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100057 AbstractUbiquitination of protein species in regulating signal transduction pathways is universally accepted as of fundamental importance for normal development, and defects in this process have been implicated in the progression of many human diseases. One pathway that has received much attention in this context is transforming growth factor‐beta (TGF‐β) signalling, particularly during the regulation of epithelial‐mesenchymal transition (EMT) and tumour progression. While E3‐ubiquitin ligases offer themselves as potential therapeutic targets, much remains to be unveiled regarding mechanisms that culminate in their regulation. With this in mind, the focus of this review highlights the regulation of the ubiquitination pathway and the significance of a recently described group of NE... BioEssays journals http://www.medworm.com/rss/comments.php?id=5137815 Tue, 16 Aug 2011 23:00:00 +0100 5137815 http://www.medworm.com/index.php?rid=5129939&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190048 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5129939 Mon, 15 Aug 2011 23:18:06 +0100 5129939 http://www.medworm.com/index.php?rid=5129938&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190047 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5129938 Mon, 15 Aug 2011 23:18:06 +0100 5129938 http://www.medworm.com/index.php?rid=5129937&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190045 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5129937 Mon, 15 Aug 2011 23:18:05 +0100 5129937 http://www.medworm.com/index.php?rid=5129936&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190044 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5129936 Mon, 15 Aug 2011 23:17:56 +0100 5129936 http://www.medworm.com/index.php?rid=5129935&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190043 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5129935 Mon, 15 Aug 2011 23:17:56 +0100 5129935 http://www.medworm.com/index.php?rid=5129934&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190042 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5129934 Mon, 15 Aug 2011 23:17:55 +0100 5129934 http://www.medworm.com/index.php?rid=5129933&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190046 Thermogenesis, muscle hyperplasia, and the origin of birds. The origin of birds from their reptilian ancestors has been classically considered to be driven by the evolution of flight. In this issue (pages 653–656) Stuart Newman presents a new theory of bird origins that emphasizes instead the adaptive role of enlarged skeletal muscles. The common ancestor of birds and lizards lost the vertebrate gene for uncoupling protein‐1 (UCP1) the product of which is essential for the generation of heat by brown fat, a tissue that protects newborns of mammals from hypothermia. This created an imperative for the direct ancestors of birds (but not “cold‐blooded” lizards) to increase the mass of skeletal muscle, the main source of body heat in modern birds and their young. Evolutionary expansio... BioEssays journals http://www.medworm.com/rss/comments.php?id=5129933 Mon, 15 Aug 2011 23:17:54 +0100 5129933 http://www.medworm.com/index.php?rid=5117106&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100064 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5117106 Mon, 08 Aug 2011 23:00:00 +0100 5117106 http://www.medworm.com/index.php?rid=5117105&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100067 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5117105 Mon, 08 Aug 2011 23:00:00 +0100 5117105 http://www.medworm.com/index.php?rid=5117104&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100050 AbstractMitochondrial DNA (mtDNA) mutations escalate with increasing age in higher organisms. However, it has so far been difficult to experimentally determine whether mtDNA mutation merely correlates with age or directly limits lifespan. A recent study shows that budding yeast can also lose functional mtDNA late in life. Interestingly, independent studies of replicative lifespan (RLS) and of mtDNA‐deficient cells show that the same mutations can increase both RLS and the division rate of yeast lacking the mitochondrial genome. These exciting, parallel findings imply a potential causal relationship between mtDNA mutation and replicative senescence. Furthermore, these results suggest more efficient methods for discovering genes that determine lifespan. (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5117104 Sun, 31 Jul 2011 23:00:00 +0100 5117104 http://www.medworm.com/index.php?rid=5085255&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100092 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5085255 Sun, 31 Jul 2011 23:00:00 +0100 5085255 http://www.medworm.com/index.php?rid=5085254&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100060 AbstractImprinted genes (IGs) are expressed or silenced according to their parent‐of‐origin. These genes are known to play a role in regulating offspring growth, development and infant behaviors such as suckling and ultrasonic calls. In adults, neurally expressed IGs coordinate several behaviors including maternal care, sex, feeding, emotionality, and cognition. However, despite evidence from human psychiatric disorders and evolutionary theory that maternally and paternally expressed genes should also regulate social behavior, little empirical data from mouse research exists. This paper discusses data from a recent study (Garfield et al., 2011) that the IG Grb10 governs unique aspects of mouse social behavior and interprets the relevance of these findings for the future of this field.E... BioEssays journals http://www.medworm.com/rss/comments.php?id=5085254 Sun, 31 Jul 2011 23:00:00 +0100 5085254 http://www.medworm.com/index.php?rid=5048292&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190041 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5048292 Thu, 21 Jul 2011 23:45:31 +0100 5048292 http://www.medworm.com/index.php?rid=5048291&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190040 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5048291 Thu, 21 Jul 2011 23:45:30 +0100 5048291 http://www.medworm.com/index.php?rid=5048290&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190038 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5048290 Thu, 21 Jul 2011 23:45:30 +0100 5048290 http://www.medworm.com/index.php?rid=5048289&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100081 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5048289 Thu, 21 Jul 2011 23:45:25 +0100 5048289 http://www.medworm.com/index.php?rid=5048288&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190037 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5048288 Thu, 21 Jul 2011 23:45:24 +0100 5048288 http://www.medworm.com/index.php?rid=5048287&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190036 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5048287 Thu, 21 Jul 2011 23:45:23 +0100 5048287 http://www.medworm.com/index.php?rid=5048286&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190039 Cover Photograph Connecting the gut microbiota with brain development. On pages 588–591, Betty Diamond et al. discuss recent evidence that shows that the gut microbiota is not only critical for intestinal function and activation of systemic immunity but that it also plays a role in brain development. The bacterial content of the gut, which changes rapidly after birth as food ingestion begins, exerts a strong influence over brain development most likely via immune signalling. Notably there is only a certain time frame during which the gut flora can influence the developing brain. In the absence of intestinal microbiota, histopathological and behavioural abnormalities arise. The interconnection between the gut microbiota and the brain may also open up new frontiers for research and new the... BioEssays journals http://www.medworm.com/rss/comments.php?id=5048286 Thu, 21 Jul 2011 23:45:22 +0100 5048286 http://www.medworm.com/index.php?rid=5048285&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100054 AbstractToxoplasma gondii is a highly successful parasite capable of infecting virtually all warm‐blooded animals by actively invading nucleated host cells and forming a modified compartment where it replicates within the cytosol. The parasite‐containing vacuole provides a safe haven, even in professional phagocytes such as macrophages, which normally destroy foreign microbes. In an effort to eliminate the parasite, the host up‐regulates a family of immunity‐related p47 GTPases (IRGs), which are recruited to the parasite‐containing vacuole, resulting in membrane rupture and digestion of the parasite. To avoid this fate, highly virulent strains of Toxoplasma coat the external surface of their vacuole with a secretory serine/threonine kinase, known as ROP18. At this host‐pathogen... BioEssays journals http://www.medworm.com/rss/comments.php?id=5048285 Thu, 21 Jul 2011 23:45:17 +0100 5048285 http://www.medworm.com/index.php?rid=5017813&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100035 AbstractRecent data have provided evidence for an unrecognised ancient lineage of green plants that persists in marine deep‐water environments. The green plants are a major group of photosynthetic eukaryotes that have played a prominent role in the global ecosystem for millions of years. A schism early in their evolution gave rise to two major lineages, one of which diversified in the world's oceans and gave rise to a large diversity of marine and freshwater green algae (Chlorophyta) while the other gave rise to a diverse array of freshwater green algae and the land plants (Streptophyta). It is generally believed that the earliest‐diverging Chlorophyta were motile planktonic unicellular organisms, but the discovery of an ancient group of deep‐water seaweeds has challenged our underst... BioEssays journals http://www.medworm.com/rss/comments.php?id=5017813 Sun, 10 Jul 2011 23:00:00 +0100 5017813 http://www.medworm.com/index.php?rid=5017812&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100040 AbstractIt is increasingly recognized that current established model systems are not sufficient to understand the evolution of biodiversity. The main limitation in developing additional model systems is the difficulty or inability to perform functional studies of target genes. Evolutionary developmental (evo‐devo) biologists have adopted a transient transgenic technique, developed over the last decade for agricultural applications, which is allowing functional studies in the most disparate plant lineages. From monocots to dicots and from herbs to trees, virus‐induced gene silencing (VIGS) has opened up a world of opportunities in plant evo‐devo. (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5017812 Sun, 10 Jul 2011 23:00:00 +0100 5017812 http://www.medworm.com/index.php?rid=5006337&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100048 AbstractHere we discuss the hypothesis that the RNA components of the Ro ribonucleoproteins (RNPs), the Y RNAs, can be processed into microRNAs (miRNAs). Although Ro RNPs, whose main protein components Ro60 and La are targeted by the immune system in several autoimmune diseases, were discovered many years ago, their function is still poorly understood. Indeed, recent data show that miRNA‐sized small RNAs can be generated from Y RNAs. This hypothesis leads also to a model in which Ro60 acts as a modulator in the Y RNA‐derived miRNA biogenesis pathway. The implications of these Y RNA‐derived miRNAs, which may be specifically produced under pathological circumstances such as in autoimmunity or during viral infections, for the enigmatic function of Ro RNPs are discussed. (Source: BioEssa... BioEssays journals http://www.medworm.com/rss/comments.php?id=5006337 Wed, 06 Jul 2011 23:00:00 +0100 5006337 http://www.medworm.com/index.php?rid=5006336&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100018 We describe here a conceptually novel approach for the generation of chimeric GEMMs based on the controlled introduction of various genetic elements in embryonic stem cells (ESCs) that are derived from existing mouse strains with a predisposition for cancer. The isolation of GEMM‐derived ESC lines is greatly facilitated by the availability of the newly defined culture media containing inhibitors that effectively preserve ESC pluripotency. The feasibility of the GEMM‐ESC approach is discussed in light of current literature and placed into the context of existing models. This approach will allow for fast and flexible validation of candidate cancer genes and drug targets and will result in a repository of GEMM‐ESC lines and corresponding vector collections that enable easy distribution ... BioEssays journals http://www.medworm.com/rss/comments.php?id=5006336 Wed, 06 Jul 2011 23:00:00 +0100 5006336 http://www.medworm.com/index.php?rid=5006335&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100072 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5006335 Wed, 06 Jul 2011 23:00:00 +0100 5006335 http://www.medworm.com/index.php?rid=5006339&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100074 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5006339 Tue, 05 Jul 2011 23:00:00 +0100 5006339 http://www.medworm.com/index.php?rid=5006338&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100024 AbstractI hypothesize here that the ability of probiotics to synthesize neuroactive compounds provides a unifying microbial endocrinology‐based mechanism to explain the hitherto incompletely understood action of commensal microbiota that affect the host's gastrointestinal and psychological health. Once ingested, probiotics enter an interactive environment encompassing microbiological, immunological, and neurophysiological components. By utilizing a trans‐disciplinary framework known as microbial endocrinology, mechanisms that would otherwise not be considered become apparent since any candidate would need to be shared among all three components. The range of neurochemicals produced by probiotics includes neurochemicals for which receptor‐based targets on immune and neuronal elements ... BioEssays journals http://www.medworm.com/rss/comments.php?id=5006338 Tue, 05 Jul 2011 23:00:00 +0100 5006338 http://www.medworm.com/index.php?rid=5017811&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100046 AbstractDuring regeneration, lost functional tissue can, in general, be replaced by different mechanisms, including proliferation of terminally differentiated cells or through differentiation of resident stem cells. It is a well‐accepted dogma that the mammalian heart cannot efficiently regenerate upon injury as a consequence of insufficient oxygen supply. This is in sharp contrast to the hearts of adult zebrafish or newts that are able to replace lost ventricular tissue. Novel data indicate that the young murine heart also has the ability to regenerate within the first week after birth using mechanisms apparently quite similar to those observed in fish. This now provides us with a good starting point to identify the molecular mechanisms that led to the loss of the regenerative capacity ... BioEssays journals http://www.medworm.com/rss/comments.php?id=5017811 Thu, 30 Jun 2011 23:00:00 +0100 5017811 http://www.medworm.com/index.php?rid=5006334&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100063 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=5006334 Thu, 30 Jun 2011 23:00:00 +0100 5006334 http://www.medworm.com/index.php?rid=4991760&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100036 AbstractThe common neurotrophin receptor (p75NTR) regulates various functions in the developing and adult nervous system. Cell survival, cell death, axonal and growth cone retraction, and regulation of the cell cycle can be regulated by p75NTR‐mediated signals following activation by either mature or pro‐neurotrophins and in combination with various co‐receptors, including Trk receptors and sortilin. Here, we review the known functions of p75NTR by cell type, receptor‐ligand combination, and whether regulated intra‐membrane proteolysis of p75NTR is required for signalling. We highlight that the generation of the intracellular domain fragment of p75NTR is associated with many of the receptor functions, regardless of its ligand and co‐receptor interactions. (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=4991760 Thu, 30 Jun 2011 23:00:00 +0100 4991760 http://www.medworm.com/index.php?rid=4959256&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100061 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=4959256 Thu, 23 Jun 2011 06:29:52 +0100 4959256 http://www.medworm.com/index.php?rid=4944233&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100034 AbstractRecent sequencing of the metazoan Oikopleura dioica genome has provided important insights, which challenges the current understanding of eukaryotic genome evolution. Many genomic features of O. dioica show deviation from the commonly observed trends in other eukaryotic genomes. For instance, O. dioica has a rapidly evolving, highly compact genome with a divergent intron‐exon organization. Additionally, O. dioica lacks the minor spliceosome and key DNA repair pathway genes. Even with a compact genome, O. dioica contains tandem repeats, comparable to other eukaryotes, and shows lineage‐specific expansion of certain protein domains. Here, we review its genomic features in the context of current knowledge, discuss implications for contemporary biology and identify areas for furthe... BioEssays journals http://www.medworm.com/rss/comments.php?id=4944233 Sun, 19 Jun 2011 07:37:40 +0100 4944233 http://www.medworm.com/index.php?rid=4944234&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100001 AbstractCephalopods are extraordinary molluscs equipped with vertebrate‐like intelligence and a unique buoyancy system for locomotion. A growing body of evidence from the fossil record, embryology and Bayesian molecular divergence estimations provides a comprehensive picture of their origins and evolution. Cephalopods evolved during the Cambrian (∼530 Ma) from a monoplacophoran‐like mollusc in which the conical, external shell was modified into a chambered buoyancy apparatus. During the mid‐Palaeozoic (∼416 Ma) cephalopods diverged into nautiloids and the presently dominant coleoids. Coleoids (i.e. squids, cuttlefish and octopods) internalised their shells and, in the late Palaeozoic (∼276 Ma), diverged into Vampyropoda and the Decabrachia. This shell internalisation appe... BioEssays journals http://www.medworm.com/rss/comments.php?id=4944234 Thu, 16 Jun 2011 23:00:00 +0100 4944234 http://www.medworm.com/index.php?rid=4932253&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190035 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=4932253 Thu, 16 Jun 2011 21:49:40 +0100 4932253 http://www.medworm.com/index.php?rid=4932252&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190034 AbstractTo read the current issue of BiotecVisions click here 10.1002/biot.201100245. (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=4932252 Thu, 16 Jun 2011 21:49:39 +0100 4932252 http://www.medworm.com/index.php?rid=4932251&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190032 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=4932251 Thu, 16 Jun 2011 21:49:39 +0100 4932251 http://www.medworm.com/index.php?rid=4932250&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100041 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=4932250 Thu, 16 Jun 2011 21:49:38 +0100 4932250 http://www.medworm.com/index.php?rid=4932249&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190031 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=4932249 Thu, 16 Jun 2011 21:49:34 +0100 4932249 http://www.medworm.com/index.php?rid=4932248&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190030 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=4932248 Thu, 16 Jun 2011 21:49:34 +0100 4932248 http://www.medworm.com/index.php?rid=4932247&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190029 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=4932247 Thu, 16 Jun 2011 21:49:33 +0100 4932247 http://www.medworm.com/index.php?rid=4932246&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201190033 Cover Photograph: Through the looking glass: The role of metabolites. Cells contain a vast amount of small metabolites that may interact with proteins and thus regulate protein localization and turnover, protein‐protein interactions and binding of proteins to nucleic acids among other things. In this issue (pages 485–489), Li and Snyder take a look at the different strategies used to discover metaboliteprotein interactions and identify several challenges faced by these approaches. A systematic investigation of metaboliteprotein interactions may help bridge the gap between genome‐wide association studies and small molecule screening studies and therefore lead to disclosure of important aspects of physiology and pathology. These findings may ultimately even provide a short list of pote... BioEssays journals http://www.medworm.com/rss/comments.php?id=4932246 Thu, 16 Jun 2011 21:49:32 +0100 4932246 http://www.medworm.com/index.php?rid=4932244&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100042 AbstractA new study entitled “Normal gut microbiota modulates brain development and behavior”, published in the Proceedings of the National Academy of Sciences, requires that we reconsider the notion that the brain is an immune‐privileged site. The authors demonstrate that intestinal microbiota must be present within a set time‐frame for normal synaptogenesis to occur in the brain. In the absence of intestinal microbiota, histopathological and behavioral abnormalities arise. These observations necessitate a new look at the many interconnections of the immune system and the brain, suggesting new frontiers for research and new therapeutic strategies for neurodevelopmental diseases. (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=4932244 Thu, 16 Jun 2011 21:49:30 +0100 4932244 http://www.medworm.com/index.php?rid=4932245&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100015 AbstractEditor's suggested further reading in BioEssaysA new paradigm in cell therapy for diabetes: Turning pancreatic α‐cells into β‐cellsAbstract (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=4932245 Wed, 15 Jun 2011 23:00:00 +0100 4932245 http://www.medworm.com/index.php?rid=4891569&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100021 AbstractThe study of mammalian corticogenesis has revealed a critical role for Polycomb group (PcG) factors in timing the execution of developmental choices. Meanwhile, the study of post‐translational modifications of PcG factors marks a symmetrical point, namely that the activity of PcG proteins is itself timed in a manner that links progression through the cell cycle to targeting of downstream genes. Finally, in a third symmetrical twist, the studies that dissect the timing of neural fate by Polycomb are also uncovering the importance of timing in the experimental mutation, since ablation of the same PcG member at different developmental stages yields dramatically different results. Here, I weave together these three lines of evidence and develop a unifying model that clarifies the dyn... BioEssays journals http://www.medworm.com/rss/comments.php?id=4891569 Tue, 31 May 2011 23:00:00 +0100 4891569 http://www.medworm.com/index.php?rid=4891568&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201000126 AbstractA crucially important part of the biosphere – the virosphere – is too often overlooked. Inclusion of the virosphere into the global picture of protein structure space reveals that 63 protein domain superfamilies in viruses do not have any structural and evolutionary relatives in modern cellular organisms. More than half of these have functions which are not virus‐specific and thus might be a source of new folds and functions for cellular life. The number of viruses on the planet exceeds that of cells by an order of magnitude and viruses evolve up to six orders of magnitude faster. As a result, cellular species are subject to a constitutive ‘flow‐through’ of new viral genetic material. Due to this and the relaxed evolutionary constraints in viruses, the transfer of domai... BioEssays journals http://www.medworm.com/rss/comments.php?id=4891568 Tue, 31 May 2011 23:00:00 +0100 4891568 http://www.medworm.com/index.php?rid=4891567&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100027 AbstractRecombination is often considered a disruptive force for well‐adapted phenotypes, but recent evidence suggests that this cost of recombination can be small. A key benefit of recombination is that it can help create proteins and regulatory circuits with novel and useful phenotypes more efficiently than point mutation. Its effectiveness stems from the large‐scale reorganization of genotypes that it causes, which can help explore far‐flung regions in genotype space. Recent work on complex phenotypes in model gene regulatory circuits and proteins shows that the disruptive effects of recombination can be very mild compared to the effects of mutation. Recombination thus can have great benefits at a modest cost, but we do not understand the reasons well. A better understanding might... BioEssays journals http://www.medworm.com/rss/comments.php?id=4891567 Tue, 31 May 2011 23:00:00 +0100 4891567 http://www.medworm.com/index.php?rid=4891566&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100065 (Source: BioEssays) BioEssays journals http://www.medworm.com/rss/comments.php?id=4891566 Tue, 31 May 2011 23:00:00 +0100 4891566 http://www.medworm.com/index.php?rid=4870686&cid=s_33755_67_f&fid=33755&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fbies.201100032 AbstractThe basic premise of the host‐defense theory is that genomic imprinting, the parent‐of‐origin expression of a subset of mammalian genes, derives from mechanisms originally dedicated to silencing repeated and retroviral‐like sequences that deeply colonized mammalian genomes. We propose that large clusters of tandemly‐repeated C/D‐box small nucleolar RNAs (snoRNAs) or microRNAs represent a novel category of sequences recognized as “genomic parasites”, contributing to the emergence of genomic imprinting in a subset of chromosomal regions that contain them. Such a view is supported by evidence derived from studies of the imprinted snoRNA‐ and/or miRNA‐encoding Dlk1‐Dio3, Snurf‐Snrpn, Sfbmt2, and C19MC domains. While adding a new piece to the challenging puzzle o... BioEssays journals http://www.medworm.com/rss/comments.php?id=4870686 Fri, 27 May 2011 22:33:18 +0100 4870686