MedWorm: Biochemistry

Analysis of Several PLA2 mRNA in Human Meningiomas

Mediators of Inflammation — Sun, 21 Mar 2010 16:57:07 +0100

In conclusion numerous genes encoding multiples forms of PLA2 are expressed in meningiomas where they might act on the phospholipid remodeling and on the local eicosanoid and/or cytokine networks. (Source: Mediators of Inflammation)

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Timothy Hla Appointed To Lead Center For Vascular Biology At Weill Cornell Medical College

Biology / Biochemistry News From Medical News Today — Sun, 21 Mar 2010 07:00:00 +0100

One of the nation's foremost vascular biologists, Dr. Timothy T. Hla, has been appointed as the new director of the Center for Vascular Biology and professor of pathology and laboratory medicine at Weill Cornell Medical College... (Source: Biology / Biochemistry News From Medical News Today)

Barrett's metaplasia: molecular mechanisms and nutritional influences.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:09:29 +0100

Authors: Slack JM, Colleypriest BJ, Quinlan JM, Yu WY, Farrant MJ, Tosh D Barrett's metaplasia is discussed in the context of a general theory for the formation of metaplasias based on developmental biology. The phenotype of a particular tissue type becomes established during embryonic development by the expression of a specific set of transcription factors. If this combination becomes altered, then the tissue type can be altered. Such events may occur by mutation or by environmental effects on gene expression, normally within the stem cell population of the tissue. A macroscopic patch of metaplastic tissue will arise only if the new gene activity state is self-sustaining in the absence of its original causes, and if the new tissue type can outgrow the parent tissue type. An important ...

Modelling Barrett's oesophagus.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:09:25 +0100

Authors: Kong J, Stairs DB, Lynch JP Barrett's oesophagus is the replacement of normal squamous oesophageal epithelium with an intestinalized columnar epithelium. Although some insight has been gained as to what Barrett's oesophagus is, how this columnar epithelium emerges from within a stratified squamous epithelium remains an unanswered question. We have sought to determine whether oesophageal keratinocytes can be trans-differentiated into Barrett's oesophagus cells. Using an Affymetrix microarray, we found unexpectedly that gene-expression patterns in the Barrett's oesophagus were only slightly more similar to the normal small intestine than they were to the normal oesophagus. Thus gene-expression patterns suggest significant molecular similarities remain between Barrett's oesophagu...

Role of the micro-environment in Barrett's carcinogenesis.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:09:22 +0100

Authors: Lao-Sirieix P, Fitzgerald RC Most epithelial cancers occur on the background of chronic exposure to damaging agents which is reflected in the long lag phase from development of a pre-invasive lesion to the development of a carcinoma. Luminal refluxate has long been recognized to be associated with Barrett's oesophagus, although causal mechanisms have not been clearly defined. Recently, obesity and dietary nitric oxide have also been implicated in the disease pathogenesis. We have demonstrated that acid can alter cell kinetics and, together with nitric oxide, can induce double-stranded DNA breaks. Aside from exposure to luminal factors, the stromal micro-environment may also be important. There is increasing evidence to suggest that inflammatory pathways such as TGF (transformi...

New models of neoplastic progression in Barrett's oesophagus.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:09:18 +0100

Authors: Pavlov K, Maley CC Research in Barrett's oesophagus, and neoplastic progression to OAC (oesophageal adenocarcinoma), is hobbled by the lack of good pre-clinical models that capture the evolutionary dynamics of Barrett's cell populations. Current models trade off tractability for realism. Computational models are perhaps the most tractable and can be used both to interpret data and to develop intuitions and hypotheses for neoplastic progression. Tissue culture models include squamous cell lines, Barrett's oesophagus cell lines and OAC cell lines, although it was recognized recently that BIC-1, SEG-1 and TE-7 are not true OAC cell lines. Some of the unrealistic aspects of the micro-environment in two-dimensional tissue culture may be overcome with the development of three-dimens...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

The role of secondary bile acids in neoplastic development in the oesophagus.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:09:13 +0100

Authors: Cronin J, Williams L, McAdam E, Eltahir Z, Griffiths P, Baxter J, Jenkins G Bile acids have been demonstrated, through the use of animal models and clinical association studies, to play a role in neoplastic development in Barrett's metaplasia. How specific bile acids promote neoplasia is as yet unknown, as are the exact identities of the important bile acid subtypes. The combination of bile subtype with appropriate pH is critical, as pH alters bile acid activity enormously. Hence glycine-conjugated bile acids are involved in neoplastic development at acidic pH (pH ~4), and unconjugated bile acids are involved in neoplastic development at more neutral pH (~6). Bile acids (at the appropriate pH) are potent DNA-damaging agents, due to the induction of ROS (reactive oxygen species...

Biomarkers in Barrett's oesophagus.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:09:09 +0100

Authors: Huang Q, Hardie LJ Biomarkers are needed to screen multiple stages in the clinical pathway of Barrett's oesophagus patients; from disease diagnosis to risk stratification and predicting response to therapy. Routes to the identification of biomarkers have been recognized by known molecular features of the disease and more recently through transcriptomic, methylation and proteomic screening approaches. The majority of Barrett's oesophagus patients remain undiagnosed in the general population. In order to develop a tool to screen for Barrett's oesophagus in the primary care setting, minimally invasive sampling methods coupled with immunocytology-based biomarkers are currently being assessed. Biomarkers may also have utility in surveillance programmes by allowing endoscopic interv...

The role of acid and bile reflux in oesophagitis and Barrett's metaplasia.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:09:06 +0100

Authors: Souza RF The precise mechanisms whereby gastro-oesophageal reflux disease causes reflux oesophagitis and Barrett's oesophagus are not clear, even though these diseases have been known to be linked for many years. Recent studies indicate a role for the reflux-induced inflammatory response of oesophageal squamous epithelial cells and the immune cells in the pathogenesis of reflux oesophagitis. Although reflux oesophagitis commonly heals with oesophageal squamous cell regeneration, in some individuals the oesophagus heals through the process of metaplasia, a condition termed Barrett's oesophagus. Recent studies indicate that individual differences in the reflux-mediated response of oesophageal squamous epithelial cells in the type of immune response and/or in signalling pathways ...

The role of Cdx genes in the gut and in axial development.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:09:03 +0100

Authors: Beck F, Stringer EJ The Cdx (Caudal-type homeobox) group of ParaHox genes (Cdx1, Cdx2 and Cdx4 in the mouse) perform multiple functions in mammalian development. Cdx1 is concerned with axial positional information, and its deletion appears to have no important effect other than a disturbance of axial patterning. In contrast, Cdx2 is required for trophoblast differentiation, axial patterning and extension, as well as for morphological specification (i.e. patterning) of gut endoderm. Cdx4-knockout animals do not present an abnormal phenotype, but, when combined with Cdx2 haploinsufficiency, present a dramatic picture involving abnormal cloacal specification. The latter is probably due in large part to defective paraxial mesodermal development in the caudal region, but may also i...

Pathophysiology of intestinal metaplasia of the stomach: emphasis on CDX2 regulation.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:08:57 +0100

Authors: Barros R, Camilo V, Pereira B, Freund JN, David L, Almeida R IM (intestinal metaplasia) of the stomach is a pre-neoplastic lesion that usually follows Helicobacter pylori infection and that confers increased risk for gastric cancer development. After setting the role played by CDX2 (Caudal-type homeobox 2) in the establishment of gastric IM, it became of foremost importance to unravel the regulatory mechanisms behind its de novo expression in the stomach. In the present paper, we review the basic pathology of gastric IM as well as the current knowledge on molecular pathways involved in CDX2 regulation in the gastric context. PMID: 20298183 [PubMed - in process] (Source: Biochemical Society Transactions)

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

The role of Cdx2 in Barrett's metaplasia.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:08:51 +0100

Authors: Colleypriest BJ, Farrant JM, Slack JM, Tosh D Metaplasia (or transdifferentiation) is defined as the transformation of one tissue type to another. Clues to the molecular mechanisms that control the development of metaplasia are implied from knowledge of the transcription factors that specify tissue identity during normal embryonic development. Barrett's metaplasia describes the development of a columnar/intestinal phenotype in the squamous oesophageal epithelium and is the major risk factor for oesophageal adenocarcinoma. This particular type of cancer has a rapidly rising incidence and a dismal prognosis. The homoeotic transcription factor Cdx2 (Caudal-type homeobox 2) has been implicated as a master switch gene for intestine and therefore for Barrett's metaplasia. Normally, ...

Cellular origin of Barrett's metaplasia and oesophageal stem cells.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:08:40 +0100

Authors: Barbera M, Fitzgerald RC Barrett's oesophagus is a metaplastic pre-malignant disorder and the only established precursor lesion for oesophageal adenocarcinoma. Barrett's oesophagus develops when the normal stratified squamous epithelium of the lower oesophagus is replaced by a columnar lined mucosa with intestinal differentiation, usually in the context of chronic gastro-oesophageal reflux disease. The cellular and molecular mechanisms by which this metaplastic transformation occurs are poorly understood. Abnormal differentiation of multipotent stem cells in the squamous oesophagus, triggered by exposure to refluxate, is one potential mechanism. These stem cells could be located in the basal layer of the squamous oesophageal epithelium and/or in the neck region of the oesophag...

Genetic diversity during the development of Barrett's oesophagus-associated adenocarcinoma: how, when and why?

Biochemical Society Transactions — Sun, 21 Mar 2010 03:08:31 +0100

Authors: Graham TA, McDonald SA Recent investigations into Barrett's oesophagus at the level of individual crypts have found significant genetic heterogeneity within a single lesion. Furthermore, this genetic diversity has been shown to predict cancer development. In the present article, we review the genetic alterations implicated in disease progression in Barrett's oesophagus and discuss how genetic diversity could arise during tumorigenesis. Three arguments are discussed: a high mutation rate coupled with strong selection, clonal interaction driving progression, and a hitherto unidentified alteration that disrupts epithelial cell homoeostasis. Suggestions are made for future research to distinguish which of these theories is the predominant mechanism in Barrett's oesophagus-associat...

Machines on Genes: Enzymes that Make, Break and Move DNA and RNA.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:08:27 +0100

Authors: Stark WM, Luisi BF, Bowater RP As the vital information repositories of the cell, the nucleic acids DNA and RNA pose many challenges as enzyme substrates. To produce, maintain and repair DNA and RNA, and to extract the genetic information that they encode, a battery of remarkable enzymes has evolved, which includes translocases, polymerases/replicases, helicases, nucleases, topoisomerases, transposases, recombinases, repair enzymes and ribosomes. An understanding of how these enzymes function is essential if we are to have a clear view of the molecular biology of the cell and aspire to manipulate genomes and gene expression to our advantage. To bring together scientists working in this fast-developing field, the Biochemical Society held a Focused Meeting, 'Machines on Genes: E...

Orchestrating serine resolvases.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:08:22 +0100

Authors: Rice PA, Mouw KW, Montaño SP, Boocock MR, Rowland SJ, Stark WM A remarkable feature of the serine resolvases is their regulation: the wild-type enzymes will catalyse intra- but not inter-molecular recombination, can sense the relative orientation of their sites and can exchange strands directionally, despite the fact that there is no net release of chemical bond energy. The key to this regulation is that they are only active within a large intertwined complex called the 'synaptosome'. Because substrate topology greatly facilitates (or, in other cases, inhibits) formation of the synaptosome, it acts as a 'topological filter'. Within the defined topology of the synaptosome, strand exchange releases supercoiling tension, providing an energy source to bias the reaction direct...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Site-specific recombination by phiC31 integrase and other large serine recombinases.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:08:18 +0100

Authors: Smith MC, Brown WR, McEwan AR, Rowley PA Most temperate phages encode an integrase for integration and excision of the prophage. Integrases belong either to the lambda Int family of tyrosine recombinases or to a subgroup of the serine recombinases, the large serine recombinases. Integration by purified serine integrases occurs efficiently in vitro in the presence of their cognate (~50 bp) phage and host attachment sites, attP and attB respectively. Serine integrases require an accessory protein, Xis, to promote excision, a reaction in which the products of the integration reaction, attL and attR, recombine to regenerate attP and attB. Unlike other directional recombinases, serine integrases are not controlled by proteins occupying accessory DNA-binding sites. Instead, it is th...

The Escherichia coli DNA translocase FtsK.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:08:15 +0100

Authors: Sherratt DJ, Arciszewska LK, Crozat E, Graham JE, Grainge I Escherichia coli FtsK is a septum-located DNA translocase that co-ordinates the late stages of cytokinesis and chromosome segregation. Relatives of FtsK are present in most bacteria; in Bacillus subtilis, the FtsK orthologue, SpoIIIE, transfers the majority of a chromosome into the forespore during sporulation. DNA translocase activity is contained within a ~ 512-amino-acid C-terminal domain, which is divided into three subdomains: alpha, beta and gamma. alpha and beta comprise the translocation motor, and gamma is a regulatory domain that interacts with DNA and with the XerD recombinase. In vitro rates of translocation of ~ 5 kb.s(-1) have been measured for both FtsK and SpoIIIE, whereas, in vivo, SpoIIIE has a compa...

The interaction of four-way DNA junctions with resolving enzymes.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:08:11 +0100

Authors: Lilley DM Four-way DNA (Holliday) junctions are resolved into duplex species by the action of the junction-resolving enzymes, nucleases selective for the structure of helical branchpoints. These have been isolated from bacteria and their phages, archaea, yeasts and mammals, including humans. They are all dimeric proteins that bind with high selectivity to DNA junctions and generate bilateral cleavage within the lifetime of the DNA-protein complex. Recent success in obtaining X-ray crystal structures of resolving enzymes bound to DNA junctions has revealed how the structural selectivity of these enzymes is achieved. PMID: 20298191 [PubMed - in process] (Source: Biochemical Society Transactions)

Maintaining a sense of direction during long-range communication on DNA.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:08:07 +0100

Authors: Szczelkun MD, Friedhoff P, Seidel R Many biological processes rely on the interaction of proteins with multiple DNA sites separated by thousands of base pairs. These long-range communication events can be driven by both the thermal motions of proteins and DNA, and directional protein motions that are rectified by ATP hydrolysis. The present review describes conflicting experiments that have sought to explain how the ATP-dependent Type III restriction-modification enzymes can cut DNA with two sites in an inverted repeat, but not DNA with two sites in direct repeat. We suggest that an ATPase activity may not automatically indicate a DNA translocase, but can alternatively indicate a molecular switch that triggers communication by thermally driven DNA sliding. The generality of th...

The Type IIB restriction endonucleases.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:08:03 +0100

Authors: Marshall JJ, Halford SE The endonucleases from the Type IIB restriction-modification systems differ from all other restriction enzymes. The Type IIB enzymes cleave both DNA strands at specified locations distant from their recognition sequences, like Type IIS nucleases, but they are unique in that they do so on both sides of the site, to liberate the site from the remainder of the DNA on a short duplex. The fact that these enzymes cut DNA at specific locations mark them as Type II systems, as opposed to the Type I enzymes that cut DNA randomly, but in terms of gene organization and protein assembly, most Type IIB restriction-modification systems have more in common with Type I than with other Type II systems. Our current knowledge of the Type IIB systems is reviewed in the pre...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Catalysis of site-specific recombination by Tn3 resolvase.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:07:59 +0100

Authors: Olorunniji FJ, Stark WM The active-site interactions involved in the catalysis of DNA site-specific recombination by the serine recombinases are still incompletely understood. Recent crystal structures of synaptic gammadelta resolvase-DNA intermediates and biochemical analysis of Tn3 resolvase mutants have provided new insights into the structure of the resolvase active site, and how interactions of the catalytic residues with the DNA substrate might promote the phosphoryl transfer reactions. PMID: 20298194 [PubMed - in process] (Source: Biochemical Society Transactions)

Ancient machinery embedded in the contemporary ribosome.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:07:54 +0100

Authors: Belousoff MJ, Davidovich C, Zimmerman E, Caspi Y, Wekselman I, Rozenszajn L, Shapira T, Sade-Falk O, Taha L, Bashan A, Weiss MS, Yonath A Structural analysis, supported by biochemical, mutagenesis and computational evidence, indicates that the peptidyltransferase centre of the contemporary ribosome is a universal symmetrical pocket composed solely of rRNA. This pocket seems to be a relic of the proto-ribosome, an ancient ribozyme, which was a dimeric RNA assembly formed from self-folded RNA chains of identical, similar or different sequences. This could have occurred spontaneously by gene duplication or gene fusion. This pocket-like entity was capable of autonomously catalysing various reactions, including peptide bond formation and non-coded or semi-coded amino acid polymeriz...

Nanomechanical constraints acting on the catalytic site of cellular RNA polymerases.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:07:50 +0100

Authors: Weinzierl RO RNAPs (RNA polymerases) are complex molecular machines containing structural domains that co-ordinate the movement of nucleic acid and nucleotide substrates through the catalytic site. X-ray images of bacterial, archaeal and eukaryotic RNAPs have provided a wealth of structural detail over the last decade, but many mechanistic features can only be derived indirectly from such structures. We have therefore implemented a robotic high-throughput structure-function experimental system based on the automatic generation and assaying of hundreds of site-directed mutants in the archaeal RNAP from Methanocaldococcus jannaschii. In the present paper, I focus on recent insights obtained from applying this experimental strategy to the bridge-helix domain. Our work demonstrate...

Substrate recognition and catalysis by flap endonucleases and related enzymes.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:07:45 +0100

Authors: Tomlinson CG, Atack JM, Chapados B, Tainer JA, Grasby JA FENs (flap endonucleases) and related FEN-like enzymes [EXO-1 (exonuclease-1), GEN-1 (gap endonuclease 1) and XPG (xeroderma pigmentosum complementation group G)] are a family of bivalent-metal-ion-dependent nucleases that catalyse structure-specific hydrolysis of DNA duplex-containing nucleic acid structures during DNA replication, repair and recombination. In the case of FENs, the ability to catalyse reactions on a variety of substrates has been rationalized as a result of combined functional and structural studies. Analyses of FENs also exemplify controversies regarding the two-metal-ion mechanism. However, kinetic studies of T5FEN (bacteriophage T5 FEN) reveal that a two-metal-ion-like mechanism for chemical catalysi...

The role of ATP in the reactions of type II DNA topoisomerases.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:07:41 +0100

Authors: Bates AD, Maxwell A Type II DNA topoisomerases catalyse changes in DNA topology in reactions coupled to the hydrolysis of ATP. In the case of DNA gyrase, which can introduce supercoils into DNA, the requirement for free energy is clear. However, the non-supercoiling type II enzymes carry out reactions that are apparently energetically favourable, so their requirement for ATP hydrolysis is not so obvious. It has been shown that many of these enzymes (the type IIA family) can simplify the topology of their DNA substrates to a level beyond that expected at equilibrium. Although this seems to explain their usage of ATP, we show that the free energies involved in topology simplification are very small (<0.2% of that available from ATP) and we argue that topology simplification m...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Synaptopathy: dysfunction of synaptic function?

Biochemical Society Transactions — Sun, 21 Mar 2010 03:07:37 +0100

Authors: Brose N, O'Connor V, Skehel P Synaptopathy is an increasingly popular term used to define key features of neurodegenerative and psychiatric disease. It implies that disruptions in synaptic structure and function are potentially the major determinant of such brain diseases. The Synaptopathies: Dysfunction of Synaptic Function Biochemical Society Focused Meeting brought together several invited speakers, supplemented with short communications from young scientists, who addressed this possibility. The talks spanned the full gamut of approaches that brought molecular, cellular, systems and whole-animal experimentation together to address how fundamental synaptic biology was increasingly informing on dysfunction in disease. The disease and models thereof discussed included Alzheime...

Confirmed rare copy number variants implicate novel genes in schizophrenia.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:07:32 +0100

Authors: Tam GW, van de Lagemaat LN, Redon R, Strathdee KE, Croning MD, Malloy MP, Muir WJ, Pickard BS, Deary IJ, Blackwood DH, Carter NP, Grant SG Understanding how cognitive processes including learning, memory, decision making and ideation are encoded by the genome is a key question in biology. Identification of sets of genes underlying human mental disorders is a path towards this objective. Schizophrenia is a common disease with cognitive symptoms, high heritability and complex genetics. We have identified genes involved with schizophrenia by measuring differences in DNA copy number across the entire genome in 91 schizophrenia cases and 92 controls in the Scottish population. Our data reproduce rare and common variants observed in public domain data from >3000 schizophrenia cas...

TorsinA and DYT1 dystonia: a synaptopathy?

Biochemical Society Transactions — Sun, 21 Mar 2010 03:07:28 +0100

Authors: Warner TT, Granata A, Schiavo G DYT1 dystonia is an autosomal dominant movement disorder, characterized by early onset of involuntary sustained muscle contractions. It is caused by a 3-bp deletion in the DYT1 gene, which results in the deletion of a single glutamate residue in the C-terminus of the protein TA (torsinA). TA is a member of the AAA+ (ATPase associated with various cellular activities) family of chaperones with multiple functions in the cell. There is no evidence of neurodegeneration in DYT1 dystonia, which suggests that mutant TA leads to functional neuronal abnormalities, leading to dystonic movements. In recent years, different functional roles have been attributed to TA, including being a component of the cytoskeleton and the NE (nuclear envelope), and involve...

Stochastic aspects of transmitter release and bioenergetic dysfunction in isolated nerve terminals.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:07:24 +0100

Authors: Nicholls DG Synaptosomes (isolated nerve terminals) have been studied for more than 40 years. The preparation allows aspects of transmitter metabolism and release to be studied ex vivo from specific brain regions of animals of any age. Conditions can be devised to enable the terminals to fire spontaneous action potentials, allowing the presynaptic control of glutamate exocytosis to be studied. Recent developments have greatly increased the sensitivity with which the bioenergetics of the intra-synaptosomal mitochondria can be investigated. PMID: 20298202 [PubMed - in process] (Source: Biochemical Society Transactions)

Endosomal sorting of AMPA receptors in hippocampal neurons.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:07:21 +0100

Authors: Hanley JG An important mechanism for the regulation of excitatory synaptic transmission in the hippocampus involves tight control of AMPAR [AMPA (alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid) receptor] trafficking to alter the number or subtype of synaptic receptors. This is achieved via the multiple stages of the endosomal system. AMPARs constitutively cycle through early endosomes and recycling endosomes to maintain synaptic receptor numbers. However, on induction of synaptic plasticity, subtle alterations are made to this cycle by the action of specific AMPAR-interacting proteins and also via a number of additional proteins that regulate endosomal sorting more generally. During long-term depression, receptors are diverted to late endosomes and lysosomes rather t...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Drug targets for amyloidosis.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:07:16 +0100

Authors: Kolstoe SE, Wood SP The amyloid hypothesis indicates that protein misfolding is at the root of many neurodegenerative disorders. Small molecules targeting the formation, clearance, aggregation to toxic oligomers or SOD (superoxide dismutase)-like activities of Abeta (amyloid beta-peptide) 1-42 have provided encouraging candidates for AD (Alzheimer's disease) medicines in animal models, although none have yet proved to be effective in human trials. We have been investigating approaches to treat systemic amyloidoses, conditions that show common features with some CNS (central nervous system) disorders. For TTR (transthyretin) amyloidosis, we are seeking small molecule compounds that stabilize the amyloidogenic protein and either prevent its structural transition to the crossed b...

Reactive hypertrophy of synaptic varicosities within the hippocampus of prion-infected mice.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:07:12 +0100

Authors: Sisková Z, Sanyal NK, Orban A, O'Connor V, Perry VH Prion diseases are characteristically accompanied by extensive synaptic pathology that can occur during the preclinical phase of the disease and, in animal models, correlates with the first decline of hippocampus-dependent cognitive functions. This pathology is defined by abnormally shaped synapses in which the postsynaptic membrane modifies its curvature and potentially engulfs the juxtaposed presynaptic membrane. Using the intrahippocampally injected ME7 prion model, we further detailed the structural alterations of the population of ostensibly intact synaptic compartments within the hippocampus during this period of extensive synaptic loss. A disease stage-dependent increase in the average PSD (postsynaptic density) a...

Synapse elimination during development and disease: immune molecules take centre stage.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:07:08 +0100

Authors: Schafer DP, Stevens B Synapse elimination is a normal developmental process occurring throughout the central and peripheral nervous systems. Meanwhile, gradual and early loss of synapses is a characteristic that is common to several neurodegenerative disease states. Recent evidence has emerged implicating molecules canonically involved in the immune system and inflammation accompanying neurodegeneration (e.g. classical complement cascade) as important players in the normal elimination of synapses in the developing nervous system. As a result, a question has emerged as to whether mechanisms underlying elimination of synapses during normal development are recapitulated and contribute to early synapse loss and nervous system dysfunction during neurodegenerative disease. The prese...

Dysfunction and recovery of synapses in prion disease: implications for neurodegeneration.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:07:04 +0100

Authors: Moreno JA, Mallucci GR Synaptic dysfunction is a key early process in many neurodegenerative diseases, but how this ultimately leads to neuronal loss is not clear. In health, there is ongoing remodelling of synapses and spines in the adult brain: their elimination and formation are continual physiological processes fundamental to learning and memory. But in neurodegenerative disease, including prion disease, lost synapses are not replaced, and their loss is followed by neuronal death. These two processes are separately regulated, with mechanistic, spatial and temporal segregation of the respective death routines of synapses and cell bodies. Mice with prion disease can be cured at the stage of early synaptic dysfunction, when they have reversible impairments at neurophysiologic...

Presynaptic dysfunction in Huntington's disease.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:07:00 +0100

Authors: Rozas JL, Gómez-Sánchez L, Tomás-Zapico C, Lucas JJ, Fernández-Chacón R HD (Huntington's disease) is produced by the expression of mutant forms of the protein htt (huntingtin) containing a pathologically expanded poly-glutamine repeat. For unknown reasons, in HD patients and HD mouse models, neurons from the striatum and cerebral cortex degenerate and lead to motor dysfunction and dementia. Synaptic transmission in those neurons becomes progressively altered during the course of the disease. However, the relationship between synaptic dysfunction and neurodegeneration in HD is not yet clear. Are there early specific functional synaptic changes preceding symptoms and neurodegeneration? What is the role of those changes in neuronal damage? Recent experime...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Synaptic dysfunction in Parkinson's disease.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:06:56 +0100

Authors: Bagetta V, Ghiglieri V, Sgobio C, Calabresi P, Picconi B In neuronal circuits, memory storage depends on activity-dependent modifications in synaptic efficacy, such as LTD (long-term depression) and LTP (long-term potentiation), the two main forms of synaptic plasticity in the brain. In the nucleus striatum, LTD and LTP represent key cellular substrates for adaptive motor control and procedural memory. It has been suggested that their impairment could account for the onset and progression of motor symptoms of PD (Parkinson's disease), a neurodegenerative disorder characterized by the massive degeneration of dopaminergic neurons projecting to the striatum. In fact, a peculiar aspect of striatal plasticity is the modulation exerted by DA (dopamine) on LTP and LTD. Our understand...

Reversibility of functional deficits in experimental models of Rett syndrome.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:06:52 +0100

Authors: Cobb S, Guy J, Bird A Mutations in the X-linked MECP2 gene are the primary cause of the severe autism spectrum disorder RTT (Rett syndrome). Deletion of Mecp2 in mice recapitulates many of the overt neurological features seen in humans, and the delayed onset of symptoms is accompanied by deficits in neuronal morphology and synaptic physiology. Recent evidence suggests that reactivation of endogenous Mecp2 in young and adult mice can reverse aspects of RTT-like pathology. In the current perspective, we discuss these findings as well as other genetic, pharmacological and environmental interventions that attempt phenotypic rescue in RTT. We believe these studies provide valuable insights into the tractability of RTT and related conditions and are useful pointers for the developme...

The developmental roles of FMRP.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:06:48 +0100

Authors: Till SM FXS (Fragile X syndrome) is the most common genetically inherited form of cognitive impairment. The predominant cause of the syndrome is the loss of a single protein, FMRP (Fragile X mental retardation protein). Many of the cognitive and behavioural features found in Fragile X individuals emerge during childhood and are associated with abnormal organization of cortical connections. However, although FMRP is expressed as early as embryogenesis, relatively little is known about its roles during development or how this may influence FXS phenotypes in adulthood. The present review focuses specifically on the evidence for the functions of FMRP during embryonic and early postnatal development. The current knowledge of the role of FMRP in FXS will be briefly summarized before...

'Holistic' synaptogenesis.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:06:44 +0100

Authors: Poulopoulos A Synapses between nerve cells in the mammalian brain are not only extremely numerous but also very diverse with respect to their structural and functional characteristics. This heterogeneity arises despite the fact that a set of common basic protein 'building blocks' is shared by many synapses. Among these, postsynaptic scaffolding proteins play a key role. They have the ability to assemble into membrane-tethered lattices and to adopt unique conformational states in different postsynaptic microenvironments, which may represent a key prerequisite of synapse heterogeneity. Analyses of such synaptic superstructures, rather than individual proteins and their interactions, are required to develop a mechanistic understanding of postsynaptic differentiation, synapse dive...

Errant ensembles: dysfunctional neuronal network dynamics in schizophrenia.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:06:40 +0100

Authors: Jones MW Most complex psychiatric disorders cannot be explained by pathology of a single brain region, but arise as a consequence of dysfunctional interactions between brain regions. Schizophrenia, in particular, has been described as a 'disconnection syndrome', but similar principles are likely to apply to depression and ADHD (attention deficit hyperactivity disorder). All these diseases are associated with impaired co-ordination of neural population activity, which manifests as abnormal EEG (electroencephalogram) and LFP (local field potential) oscillations both within and across subcortical and cortical brain regions. Importantly, it is increasingly possible to link oscillations and interactions at distinct frequencies to the physiology and/or pathology of distinct classes ...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

S-acylation by the DHHC protein family.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:06:35 +0100

Authors: Greaves J, Chamberlain LH A family of 23 DHHC (Asp-His-His-Cys) proteins that function as mammalian S-acyltransferases has been identified, reinvigorating the study of protein S-acylation. Recent studies have continued to reveal how S-acylation affects target proteins, and have provided glimpses of how DHHC-substrate specificity might be achieved. PMID: 20298214 [PubMed - in process] (Source: Biochemical Society Transactions)

The anti-allodynic alpha(2)delta ligand pregabalin inhibits the trafficking of the calcium channel alpha(2)delta-1 subunit to presynaptic terminals in vivo.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:06:31 +0100

Authors: Bauer CS, Rahman W, Tran-van-Minh A, Lujan R, Dickenson AH, Dolphin AC Neuropathic pain is caused by lesion or dysfunction of the peripheral sensory nervous system. Up-regulation of the voltage-gated Ca(2+) channel subunit alpha(2)delta-1 in DRG (dorsal root ganglion) neurons and the spinal cord correlates with the onset of neuropathic pain symptoms such as allodynia in several animal models of neuropathic pain. The clinically important anti-allodynic drugs gabapentin and pregabalin are alpha(2)delta-1 ligands, but how these drugs alleviate neuropathic pain is poorly understood. In the present paper, we review recent advances in our understanding of their molecular mechanisms. PMID: 20298215 [PubMed - in process] (Source: Biochemical Society Transactions)

Presynaptic roles of intracellular Ca(2+) stores in signalling and exocytosis.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:06:26 +0100

Authors: Nizami S, Lee VW, Davies J, Long P, Jovanovic JN, Sihra TS The signalling roles of Ca(2+)(ic) (intracellular Ca(2+)) stores are well established in non-neuronal and neuronal cells. In neurons, although Ca(2+)(ic) stores have been assigned a pivotal role in postsynaptic responses to G(q)-coupled receptors, or secondarily to extracellular Ca(2+) influx, the functions of dynamic Ca(2+)(ic) stores in presynaptic terminals remain to be fully elucidated. In the present paper, we review some of the recent evidence supporting an involvement of Ca(2+)(ic) in presynaptic function, and discuss loci at which this source of Ca(2+) may impinge. Nerve terminal preparations provide good models for functionally examining putative Ca(2+)(ic) stores under physiological and pathophysiological sti...

Are synapses targets of nanoparticles?

Biochemical Society Transactions — Sun, 21 Mar 2010 03:06:21 +0100

Authors: Fedorovich SV, Alekseenko AV, Waseem TV The last few years have been marked by real breakthroughs in the field of nanotechnology. Application of nanoparticles was proposed for diagnosis and treatment of different central nervous system diseases. Exposure to nanoparticles in vivo increases the risk of onset of neurodegenerative diseases and nanoparticles are apparently able to kill neurons in vitro. We suggested that presynaptic terminals of neurons are another target for nanoparticles, beyond the already established microglial cells. Ferritin was chosen as a prototypic nanoparticle model. We found that even a high concentration of ferritin, 800 mug/ml, was not able to induce spontaneous release of [(14)C]glutamate. In contrast, [(14)C]glutamate uptake was inhibited by ferritin...

Alzheimer's disease and amyloid beta-peptide deposition in the brain: a matter of 'aging'?

Biochemical Society Transactions — Sun, 21 Mar 2010 03:06:15 +0100

Authors: Moro ML, Collins MJ, Cappellini E Biomolecules can experience aging processes that limit their long-term functionality in organisms. Typical markers of protein aging are spontaneous chemical modifications, such as AAR (amino acid racemization) and AAI (amino acid isomerization), mainly involving aspartate and asparagine residues. Since these modifications may affect folding and turnover, they reduce protein functionality over time and may be linked to pathological conditions. The present mini-review describes evidence of AAR and AAI involvement in the misfolding and brain accumulation of Abeta (amyloid beta-peptide), a central event in AD (Alzheimer's disease) synaptic dysfunctions. Structural alterations introduced by site-specific modifications linked to protein aging may af...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Change in tau phosphorylation associated with neurodegeneration in the ME7 model of prion disease.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:06:09 +0100

Authors: Asuni AA, Perry VH, O'Connor V Hyperphosphorylation of the microtubule-associated protein tau is a significant determinant in AD (Alzheimer's disease), where it is associated with disrupted axonal transport and probably causes synaptic dysfunction. Although less well studied, hyperphosphorylation has been observed in prion disease. We have investigated the expression of hyperphosphorylated tau in the hippocampus of mice infected with the ME7 prion agent. In ME7-infected animals, there is a selective loss of CA1 synapse, first discernable at 13 weeks of disease. There is a potential that dysfunctional axonal transport contributes to this synaptopathy. Thus investigating hyperphosphorylated tau that is dysfunctional in AD could illuminate whether and how they are significant in ...

Metallothioneins and copper metabolism are candidate therapeutic targets in Huntington's disease.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:06:05 +0100

Authors: Hands SL, Mason R, Sajjad MU, Giorgini F, Wyttenbach A HD (Huntington's disease) is caused by a polyQ (polyglutamine) expansion in the huntingtin protein, which leads to protein misfolding and aggregation of this protein. Abnormal copper accumulation in the HD brain was first reported more than 15 years ago. Recent findings show that copper-regulatory genes are induced during HD and copper binds to an N-terminal fragment of huntingtin, supporting the involvement of abnormal copper metabolism in HD. We have demonstrated that in vitro copper accelerates the fibrillization of an N-terminal fragment of huntingtin with an expanded polyQ stretch (httExon1). As we found that copper also increases polyQ aggregation and toxicity in mammalian cells expressing httExon1, we investigated f...

Caenorhabditis elegans: a useful tool to decipher neurodegenerative pathways.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:06:02 +0100

We describe recent findings in this area and show how C. elegans is being used to broaden our knowledge of human neurodegenerative diseases. PMID: 20298221 [PubMed - in process] (Source: Biochemical Society Transactions)

Disruption of neuronal function by soluble hyperphosphorylated tau in a Drosophila model of tauopathy.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:05:57 +0100

Authors: Cowan CM, Chee F, Shepherd D, Mudher A Axonal microtubules are essential for transport of materials to the synapse. Compromised microtubules and synaptic loss have been demonstrated in AD (Alzheimer's disease), which is believed to contribute to cognitive dysfunction before neuronal death in the early stages of the disease. The mechanism by which hyperphosphorylated tau, the building block of neurofibrillary tangles, one of the pathological hallmarks of AD, disrupts neuronal and synaptic function is unclear. There is a theory that hyperphosphorylated tau does not bind effectively to microtubules and is no longer able to function in stabilizing them, thus axonal transport can no longer proceed efficiently. This leads to synaptic dysfunction. We have tested this theory in a Dros...

Cell-cell interactions during patterning of the Arabidopsis anther.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:05:54 +0100

Authors: Feng X, Dickinson HG Key steps in the evolution of the angiosperm anther include the patterning of the concentrically organized microsporangium and the incorporation of four such microsporangia into a leaf-like structure. Mutant studies in the model plant Arabidopsis thaliana are leading to an increasingly accurate picture of (i) the cell lineages culminating in the different cell types present in the microsporangium (the microsporocytes, the tapetum, and the middle and endothecial layers), and (ii) some of the genes responsible for specifying their fates. However, the processes that confer polarity on the developing anther and position the microsporangia within it remain unclear. Certainly, data from a range of experimental strategies suggest that hormones play a central role...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Life after meiosis: patterning the angiosperm male gametophyte.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:05:50 +0100

Authors: Borg M, Twell D Pollen grains represent the highly reduced haploid male gametophyte generation in angiosperms. They play an essential role in plant fertility by generating and delivering twin sperm cells to the embryo sac to undergo double fertilization. The functional specialization of the male gametophyte and double fertilization are considered to be key innovations in the evolutionary success of angiosperms. The haploid nature of the male gametophyte and its highly tractable ontogeny makes it an attractive system to study many fundamental biological processes, such as cell fate determination, cell-cycle progression and gene regulation. The present mini-review encompasses key advances in our understanding of the molecular mechanisms controlling male gametophyte patterning in...

Inter-cell-layer signalling during Arabidopsis ovule development mediated by the receptor-like kinase STRUBBELIG.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:05:47 +0100

Authors: Fulton L, Vaddepalli P, Yadav RK, Batoux M, Schneitz K Plant organs, such as ovules and flowers, arise through cellular events that are precisely co-ordinated between cells within and across clonally distinct cell layers. Receptor-like kinases are cell-surface receptors that perceive and relay intercellular information. In Arabidopsis the leucine-rich repeat receptor-like kinase STRUBBELIG (SUB) is required for integument initiation and outgrowth during ovule development, floral organ shape and the control of the cell division plane in the first subepidermal cell layer of floral meristems, among other functions. A major goal is to understand SUB-mediated signal transduction at the molecular level. Present evidence suggests that SUB affects neighbouring cells in a non-cell-auto...

Self-incompatibility in Papaver: identification of the pollen S-determinant PrpS.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:05:43 +0100

Authors: Poulter NS, Wheeler MJ, Bosch M, Franklin-Tong VE Many flowering plants are hermaphrodite, posing the problem of self-fertilization and the subsequent loss of the genetic fitness of the offspring. To prevent this, many plants have developed a genetically controlled mechanism called self-incompatibility (SI). When the male and female S-determinants match, self (incompatible) pollen is recognized and rejected before fertilization can occur. In poppy (Papaver rhoeas), the pistil S-determinant (PrsS) is a small secreted protein that interacts with incompatible pollen, initiating a Ca(2+)-dependent signalling network. SI triggers several downstream events, including depolymerization of the cytoskeleton, phosphorylation of two soluble inorganic pyrophosphatases and an MAPK (mitogen-...

Functional genomics of pollen tube-pistil interactions in Arabidopsis.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:05:40 +0100

Authors: Palanivelu R, Johnson MA The pollen tube represents an attractive model system for functional genomic analysis of the cell-cell interactions that mediate guided cellular growth. The pollen tube extends through pistil tissues and responds to guidance cues that direct the tube towards an ovule, where it releases sperm for fertilization. Pollen is readily isolated from anthers, where it is produced, and can be induced to produce a tube in vitro. Interestingly, pollen tube growth is significantly enhanced in pistils, and pollen tubes are rendered competent to respond to guidance cues after growth in a pistil. This potentiation of the pollen tube by the pistil suggested that pollen tubes alter their gene-expression programme in response to their environment. Recently, the transcrip...

Male gamete biology in flowering plants.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:05:35 +0100

Authors: Russell SD, Gou X, Wei X, Yuan T Flowering plant reproduction is characterized by double fertilization, in which two diminutive brother sperm cells initiate embryo and endosperm. The role of the male gamete, although studied structurally for over a century at various levels, is still being explored on a molecular and cellular level. The potential of the male to influence development has been historically underestimated and the reasons for this are obvious: limitations provided by maternal imprinting, the much greater cellular volume of female gametes and the general paucity of paternal effects. However, as more is known about molecular expression of chromatin-modifying proteins, ubiquitin pathway proteins and transcription factors in sperm cells, as well as their ability to ac...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Reproductive cross-talk: seed development in flowering plants.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:05:32 +0100

Authors: Nowack MK, Ungru A, Bjerkan KN, Grini PE, Schnittger A Flowering plants have evolved to be a predominant life form on earth. A common principle of flowering plants and probably one of the main reasons for their evolutionary success is the rapid development of an embryo next to a supporting tissue called the endosperm. The embryo and the endosperm are protected by surrounding maternal tissues, the integuments, and the trinity of integuments, embryo and endosperm comprise the plant seed. For proper seed development, these three structures have to develop in a highly controlled and co-ordinated manner, representing a paradigm for cell-cell communication during development. Communication pathways between the endosperm and the seed coat are now beginning to be unravelled. Moreover,...

Floral stem cells: from dynamic balance towards termination.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:05:25 +0100

Authors: Sun B, Ito T During early flower development in Arabidopsis, floral stem cells proliferate and produce a sufficient amount of cells that are recruited for organogenesis. However, after the central organ primordia initiate, stem cell activity in the floral meristem is terminated to ensure the differentiation of a fixed number of floral organs. Underlying this process, the genetic programme regulating the fate of floral meristems undergoes a shift from a spatially balanced signalling scheme for stem cell maintenance to a temporally controlled transcriptional scheme for stem cell termination. Precise timing of stem cell termination is a key issue for flower development, which is secured by the orchestration of multiple regulators in transcriptional and epigenetic regulation. ...

Through a generation darkly: small RNAs in the gametophyte.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:05:22 +0100

Authors: Grant-Downton RT The various classes of small non-coding RNAs are a fundamentally important component of the transcriptome. These molecules have roles in many essential processes such as regulation of gene expression at the transcriptional and post-transcriptional levels, guidance of DNA methylation and defence against selfish replicators such as transposons. Their diversity and functions in the sporophytic generation of angiosperms is well explored compared with the gametophytic generation, where little is known about them. Recent progress in understanding their abundance, diversity and function in the gametophyte is reviewed. PMID: 20298231 [PubMed - in process] (Source: Biochemical Society Transactions)

Protein interactions and subcellular localization in S-RNase-based self-incompatibility.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:05:14 +0100

Authors: Sims TL, Patel A, Shrestha P The recent identification of several proteins playing key roles in S-RNase-based gametophytic self-incompatibility has led both to a greater understanding of the molecular biology of this response, as well as to questions regarding the precise mechanism by which compatible pollen tubes are recognized and accepted. A proposed variant SCF(SLF) (where SCF is SSK1/cullin/F-box and SLF is S-locus F-box) ubiquitin ligase complex is thought to play a central role in recognizing and inhibiting non-self S-RNases, but the exact role of ubiquitination remains unclear. How the possible sequestration of non-self S-RNases in a pollen vacuolar compartment can be reconciled with the need for protein interaction between S-RNase and the SCF(SLF) complex needs to be ...

Female gametophyte-controlled pollen tube guidance.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:05:11 +0100

Authors: Márton ML, Dresselhaus T During the evolution of flowering plants, their sperm cells have lost mobility and are transported from the stigma to the female gametophyte via the pollen tube to achieve double fertilization. Pollen tube growth and guidance is largely governed by the maternal sporophytic tissues of the stigma, style and ovule. However, the last phase of the pollen tube path is under female gametophyte control and is expected to require extensive cell-cell communication events between both gametophytes. Until recently, little was known about the molecules produced by the female gametophyte that are involved in this process. In the present paper, we review the most recent development in this field and focus on the role of secreted candidate signalling ligands. ...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Sporophytic control of pollen tube growth and guidance in grasses.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:05:02 +0100

Authors: Lausser A, Dresselhaus T Pollen tube growth and guidance in the female tissues of flowering plants is a long-studied and anatomically well-described process. A large number of gene products and chemical compounds involved have been identified in the last 20 years, and some underlying molecular mechanisms including self-incompatibility in the Brassicaceae, Solanaceae and Papaveraceae are now well understood. However, the largest part of the pollen tube pathway inside the transmitting tract towards the ovule harbouring the female gametophyte still requires intensive investigations. Especially in the economically most import plant family, the Poaceae or grasses, progamic pollen tube development is barely understood. Using maize as a model, we propose to divide pollen tube germina...

Let's get physical: gamete interaction in flowering plants.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:04:59 +0100

Authors: Sprunck S Fertilization comprises a series of precisely orchestrated steps that culminate in the fusion of male and female gametes. The most intimate steps during fertilization encompass gamete recognition, adhesion and fusion. In animals, some binding-effector proteins and enzymes have been identified that act on the cell surfaces of the gametes to regulate gamete compatibility and fertilization success. In contrast, exploring plant gamete interaction during double fertilization, a characteristic trait of flowering plants, has been hampered for a long time because of the protected location of the female gametes and technical limitations. Over the last couple of years, however, the use of advanced methodologies, new imaging tools and new mutants has provided deeper insights in...

Recent achievements and trends in experimental plant biology.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:04:54 +0100

Authors: Strzałka K Between 21 and 25 September 2009, Krakow hosted the 4th Conference of the Polish Society of Experimental Plant Biology, co-organized with the Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, and supported by the Biochemical Society. The aim of the conference was to present and discuss the most important topics in different disciplines of plant experimental science as well as to facilitate the interaction and co-operation between scientists. To achieve this goal, about 30 top specialists in various areas of plant biology were invited to give plenary lectures in the following sessions: Plant structure and development; Plant-microbial interactions; Mitochondria and chloroplasts in cell metabolism; Stress tolerance in plants;...

The role of chemical dynamics in plant morphogenesis(1).

Biochemical Society Transactions — Sun, 21 Mar 2010 03:04:51 +0100

Authors: Holloway DM In biological development, the generation of shape is preceded by the spatial localization of growth factors. Localization, and how it is maintained or changed during the process of growth, determines the shapes produced. Mathematical models have been developed to investigate the chemical, mechanical and transport properties involved in plant morphogenesis. These synthesize biochemical and biophysical data, revealing underlying principles, especially the importance of dynamics in generating form. Chemical kinetics has been used to understand the constraints on reaction and transport rates to produce localized concentration patterns. This approach is well developed for understanding de novo pattern formation, pattern spacing and transitions from one pattern to anoth...

Regulation of plant light harvesting by thermal dissipation of excess energy.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:04:48 +0100

Authors: de Bianchi S, Ballottari M, Dall'osto L, Bassi R Elucidating the molecular details of qE (energy quenching) induction in higher plants has proven to be a major challenge. Identification of qE mutants has provided initial information on functional elements involved in the qE mechanism; furthermore, investigations on isolated pigment-protein complexes and analysis in vivo and in vitro by sophisticated spectroscopic methods have been used for the elucidation of mechanisms involved. The aim of the present review is to summarize the current knowledge of the phenotype of npq (non-photochemical quenching)-knockout mutants, the role of gene products involved in the qE process and compare the molecular models proposed for this process. PMID: 20298238 [PubMed - in process] (Source: ...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Involvement of mitochondria in the control of plant cell NAD(P)H reduction levels.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:04:45 +0100

Authors: Rasmusson AG, Wallström SV NADPH and NADH mediate reductant flow between cellular processes, linking central carbon and energy metabolism with intermediary metabolism, stress defence and development. Recent investigations have revealed paths of functional interactions, and have suggested that mitochondrial NADPH oxidation, especially together with the oxidative pentose phosphate pathway, is an important regulator of the cytosolic NADPH reduction level. Furthermore, stress-dependent metabolic pathways substantially affect the NADPH reduction level in particular physiological situations. The mitochondrial impact on the NADPH reduction level provides a model example of the physiological significance of the mitochondrial NAD(P)H dehydrogenase set-up, which is more complex in ...

Regulation of plant gene expression by alternative splicing.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:04:42 +0100

Authors: Simpson CG, Manthri S, Raczynska KD, Kalyna M, Lewandowska D, Kusenda B, Maronova M, Szweykowska-Kulinska Z, Jarmolowski A, Barta A, Brown JW AS (alternative splicing) is a post-transcriptional process which regulates gene expression through increasing protein complexity and modulating mRNA transcript levels. Regulation of AS depends on interactions between trans-acting protein factors and cis-acting signals in the pre-mRNA (precursor mRNA) transcripts, termed 'combinatorial' control. Dynamic changes in AS patterns reflect changes in abundance, composition and activity of splicing factors in different cell types and in response to cellular or environmental cues. Whereas the SR protein family of splicing factors is well-studied in plants, relatively little is known about other ...

Nucleolar RNPs: from genes to functional snoRNAs in plants.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:04:38 +0100

Authors: Rodor J, Letelier I, Holuigue L, Echeverria M The snoRNAs (small nucleolar RNAs) and related scaRNAs (small RNAs in the Cajal bodies) represent a major class of nuclear RNAs that guide 2'-O-ribose methylation and pseudouridylation of rRNAs, snRNAs (small nuclear RNAs) and other RNA targets. In vivo, all snoRNAs associate with a set of four highly conserved nucleolar proteins, forming the functional snoRNPs (small nucleolar ribonucleoproteins). The core structure of these mature snoRNPs has now been well described in eukaryotes, but less is known of their biogenesis. Recent data in animals and yeast reveal that assembly of the snoRNPs is a complex process that implicates several auxiliary proteins and transient protein-protein interactions. This new level of snoRNP regulation i...

Recent developments in photorespiration research.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:04:34 +0100

Authors: Bauwe H Photorespiration is the light-dependent release of CO(2) initiated by Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase) during oxygenic photosynthesis. It occurs during the biochemical reactions of the photorespiratory C(2) cycle, which is an ancillary metabolic process that allows photosynthesis to occur in oxygen-containing environments. Recent research has identified the genes for many plant photorespiratory enzymes, allowing precise functional analyses by reverse genetics. Similar studies with cyanobacteria disclosed the evolutionary origin of photorespiratory metabolism in these ancestors of plastids. PMID: 20298242 [PubMed - in process] (Source: Biochemical Society Transactions)

Exploiting induced variation to dissect quantitative traits in barley.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:04:31 +0100

Authors: Druka A, Franckowiak J, Lundqvist U, Bonar N, Alexander J, Guzy-Wrobelska J, Ramsay L, Druka I, Grant I, Macaulay M, Vendramin V, Shahinnia F, Radovic S, Houston K, Harrap D, Cardle L, Marshall D, Morgante M, Stein N, Waugh R The identification of genes underlying complex quantitative traits such as grain yield by means of conventional genetic analysis (positional cloning) requires the development of several large mapping populations. However, it is possible that phenotypically related, but more extreme, allelic variants generated by mutational studies could provide a means for more efficient cloning of QTLs (quantitative trait loci). In barley (Hordeum vulgare), with the development of high-throughput genome analysis tools, efficient genome-wide identification of genetic loci...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Mutations in genes controlling the biosynthesis and accumulation of inositol phosphates in seeds.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:04:27 +0100

Authors: Rasmussen SK, Ingvardsen CR, Torp AM Most of the phosphorus in the resting seed is stored inside protein storage vacuoles as PA (phytic acid; InsP(6)). The biosynthesis and accumulation of PA can be detected beginning from a few days after anthesis and seem to continue during seed development until maturation. The first step in PA biosynthesis is the formation of Ins3P by conversion of glucose 6-phosphate. This is then followed by a sequential and ordered phosphorylation of the remaining five positions of the inositol ring by a number of kinases, resulting in PA. Identification of low-PA mutants in cereals, legumes and Arabidopsis is instrumental for resolving the biosynthetic pathway and identification of genes controlling the accumulation of PA. Mutations in seven genes invo...

Genistein: a natural isoflavone with a potential for treatment of genetic diseases.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:04:24 +0100

Authors: Wegrzyn G, Jakóbkiewicz-Banecka J, Gabig-Cimińska M, Piotrowska E, Narajczyk M, Kloska A, Malinowska M, Dziedzic D, Gołebiewska I, Moskot M, Wegrzyn A Genistein [4',5,7-trihydroxyisoflavone or 5,7-dihydroxy-3-(4-hydroxyphenyl)-4H-1-benzopyran-4-one] is a natural isoflavone occurring in many plants known to possess various biological activities, ranging from phyto-oestrogenic to antioxidative actions. Recent studies indicated that this isoflavone can also be considered as a drug for as yet untreatable genetic diseases. In the present review, we discuss a plausible use of genistein in treatment of two genetic disorders: CF (cystic fibrosis) and MPS (mucopolysaccharidosis). Although various biological actions of genistein are employed in these two cases, in vitro...

Light-driven regulatory mechanisms in the photosynthetic antenna complex LHCII.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:04:20 +0100

Authors: Gruszecki WI Protection against strong-light-induced photodamage of the photosynthetic apparatus and entire organisms is a vital activity in plants and is also realized at the molecular level of the antenna complexes. Reported recently, the regulatory mechanisms which operate in the largest plant antenna complex, LHCII (light-harvesting complex II), based on light-driven processes, are briefly reviewed and discussed. Among those processes are the light-induced twisting of the configuration of the LHCII-bound neoxanthin, the light-induced configurational transition of the LHCII-bound violaxanthin, the light-induced trimer-monomer transition in LHCII and the blue-light-induced excitation quenching in LHCII. The physiological importance of the processes reviewed is also discussed...

Phosphatidylinositol 4,5-bisphosphate regulates plant K(+) channels.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:04:17 +0100

Authors: Wigoda N, Ma X, Moran N Phosphoinositides play an important role in both abiotic and biotic signalling in plants. The signalling cascade may include the production of second messengers by hydrolysis of PtdIns(4,5)P(2). However, increasingly, PtdIns(4,5)P(2) itself is shown to mediate signalling by regulating target proteins. The present mini-review summarizes the experimentally demonstrated effects of PtdIns(4,5)P(2) on plant K(+) channels and examines their structure for candidate sites of direct PtdIns(4,5)P(2)-protein interaction. PMID: 20298247 [PubMed - in process] (Source: Biochemical Society Transactions)

Phytochrome three-dimensional structures and functions.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:04:13 +0100

Authors: Hughes J The complete three-dimensional sensory module structures of the Pr ground state of Synechocystis 6803 Cph1 and the unusual Pfr ground state of the bacteriophytochrome PaBphP (PDB codes 2VEA and 3C2W respectively) have now been solved, revealing an asymmetrical dumbbell form made up of a PAS (Period/ARNT/Singleminded)-GAF (cGMP phosphodiesterase/adenylate cyclase/FhlA) bidomain carrying the chromophore and the smaller PHY (phytochrome-specific) domain. The PHY domain is structurally related to the GAF family, but carries an unusual tongue-like structure which contacts the larger lobe to seal the chromophore pocket. In 2VEA, the tongue makes intimate contact with the helical N-terminus; both the N-terminus and the tongue structures are quite different in 3C2W. As expect...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Auxin and strigolactones in shoot branching: intimately connected?

Biochemical Society Transactions — Sun, 21 Mar 2010 03:04:09 +0100

Authors: Stirnberg P, Ward S, Leyser O Axillary meristems form in the axils of leaves. After an initial phase of meristematic activity during which a small axillary bud is produced, they often enter a state of suspended growth from which they may be released to form a shoot branch. This post-embryonic growth plasticity is typical of plants and allows them to adapt to changing environmental conditions. The shoot architecture of genotypically identical plants may display completely contrasting phenotypes when grown in distinct environmental niches, with one having only a primary inflorescence and many arrested axillary meristems and the other displaying higher orders of branches. In order to cease and resume growth as required, the plant must co-ordinate its intrinsic developmental progr...

Recycling domains in plant cell morphogenesis: small GTPase effectors, plasma membrane signalling and the exocyst.

Biochemical Society Transactions — Sun, 21 Mar 2010 03:04:06 +0100

Authors: Zárský V, Potocký M The Rho/Rop small GTPase regulatory module is central for initiating exocytotically ACDs (active cortical domains) in plant cell cortex, and a growing array of Rop regulators and effectors are being discovered in plants. Structural membrane phospholipids are important constituents of cells as well as signals, and phospholipid-modifying enzymes are well known effectors of small GTPases. We have shown that PLDs (phospholipases D) and their product, PA (phosphatidic acid), belong to the regulators of the secretory pathway in plants. We have also shown that specific NOXs (NADPH oxidases) producing ROS (reactive oxygen species) are involved in cell growth as exemplified by pollen tubes and root hairs. Most plant cells exhibit several distinct plas...

A Battery of Cell- and Structure-specific Markers for the Adult Porcine Retina

Journal of Histochemistry and Cytochemistry — Sat, 20 Mar 2010 16:55:27 +0100

In conclusion, all immunohistochemical protocols presented here will be applicable in fixed, cryosectioned pig retina. (J Histochem Cytochem 58:377–389, 2010) (Source: Journal of Histochemistry and Cytochemistry)

Identification of Markers for Newly Formed {beta}-Cells in the Perinatal Period: A Time of Recognized {beta}-Cell Immaturity

Journal of Histochemistry and Cytochemistry — Sat, 20 Mar 2010 16:55:27 +0100

Markers of β-cell maturity would be useful in staging the differentiation of stem/progenitor cells to β-cells whether in vivo or in vitro. We previously identified markers for newly formed β-cells in regenerating rat pancreases after 90% partial pancreatectomy. To test the generality of these markers of newly formed β-cells, we examined their expression during the perinatal period, a time of recognized β-cell immaturity. We show by semiquantitative RT-PCR and immunostaining over the time course from embryonic day 18/20 to birth, 1 day, 2 days, 3 days, 7 days, and adult that MMP-2, CK-19, and SPD are truly markers of new and immature β-cells and that their expression transiently peaks in the perinatal period and is not entirely synchronous. The shared expressio...

Two-color Fluorescence Labeling in Acrolein-fixed Brain Tissue

Journal of Histochemistry and Cytochemistry — Sat, 20 Mar 2010 16:55:27 +0100

Acrolein is a potent fixative that provides both excellent preservation of ultrastructural morphology and retention of antigenicity, thus it is frequently used for immunocytochemical detection of antigens at the electron microscopic level. However, acrolein is not commonly used for fluorescence microscopy because of concerns about possible autofluorescence and destruction of the luminosity of fluorescent dyes. Here we describe a simple protocol that allows fine visualization of two fluorescent markers in 40-µm sections from acrolein-perfused rat brain. Autofluorescence was removed by pretreatment with 1% sodium borohydride for 30 min, and subsequent incubation in a 50% ethanol solution containing 0.3% hydrogen peroxide enhanced fluorescence labeling. Thus, fluorescence labeling can b...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Synthesis and Organization of Hyaluronan and Versican by Embryonic Stem Cells Undergoing Embryoid Body Differentiation

Journal of Histochemistry and Cytochemistry — Sat, 20 Mar 2010 16:55:27 +0100

Embryonic stem cells (ESCs) provide a convenient model to probe the molecular and cellular dynamics of developmental cell morphogenesis. ESC differentiation in vitro via embryoid bodies (EBs) recapitulates many aspects of early stages of development, including the epithelial–mesenchymal transition (EMT) of pluripotent cells into more differentiated progeny. Hyaluronan and versican are important extracellular mediators of EMT processes, yet the temporal expression and spatial distribution of these extracellular matrix (ECM) molecules during EB differentiation remains undefined. Thus, the objective of this study was to evaluate the synthesis and organization of hyaluronan and versican by using murine ESCs during EB differentiation. Hyaluronan and versican (V0 and V1 isoforms), visualiz...

Fixative Composition Alters Distributions of Immunoreactivity for Glutaminase and Two Markers of Nociceptive Neurons, Nav1.8 and TRPV1, in the Rat Dorsal Root Ganglion

Journal of Histochemistry and Cytochemistry — Sat, 20 Mar 2010 16:55:27 +0100

In this study, we compared the effects of five formaldehyde concentrations between 0.25% and 4.0% (w/v) and five picric acid concentrations between 0.0% and 0.8% (w/v) on the IR of GLS, the voltage-gated sodium channel 1.8 (Nav1.8), and the capsaicin receptor TRPV1. We also compared the effects of five incubation time lengths from 2 to 192 hr, in primary antiserum on IR. Lowering formaldehyde concentration elevated IR for all three antigens, while raising picric acid concentration increased Nav1.8 and TRPV1 IR. Increasing IR improved detection sensitivity, which led to higher percentages of labeled DRG neurons. By selecting fixation conditions that optimized IR, we found that all DRG neurons express GLS, 69% of neurons express Nav1.8, and 77% of neurons express TRPV1, indicating that some ...

Retention of Pax3 Expression in Satellite Cells of Muscle Spindles

Journal of Histochemistry and Cytochemistry — Sat, 20 Mar 2010 16:55:27 +0100

Intrafusal fibers within muscle spindles retain features characteristic of immaturity, unlike the larger and more numerous extrafusal fibers constituting the bulk of skeletal muscle. Satellite cells (SCs), myogenic progenitors, are detected on the surfaces of both intrafusal and extrafusal fibers, but little is known of spindle SCs. We have recently demonstrated that, like their extrafusal counterparts, SCs in muscle spindles of posthatch chickens express paired box transcription factor 7 (Pax7) protein. During vertebrate embryogenesis, myogenic progenitors express both Pax7 and Pax3 proteins. In postnatal mice, Pax3 appears in rare SC subsets, whereas Pax7 is expressed by all SCs within extrafusal fibers. Here we test the hypothesis that Pax3 protein maintains localized expression within ...

CD117-positive Cells of the Heart: Progenitor Cells or Mast Cells?

Journal of Histochemistry and Cytochemistry — Sat, 20 Mar 2010 16:55:27 +0100

Human cardiac stem/progenitor cells and their potential for repair of heart injury are a current hot topic of research. CD117 has been used frequently as a marker for identification of stem/progenitor cells in the heart. However, cardiac mast cells, which are also CD117+, have not been excluded by credible means when selecting putative cardiac progenitors by using CD117 as a marker. We evaluated the relationship between CD117+ cells and mast cells in the left ventricle of human hearts (n=5 patients, ages 1 week–75 years) with the well-established mast cell markers tryptase, toluidine blue, and thionine. A large number (85–100%) of CD117+ cells in the human heart were specifically identified as mast cells. In addition, mast cells showed weak or moderate CD45 immunostaining signa...

The E3 Ligase Axotrophin/MARCH-7: Protein Expression Profiling of Human Tissues Reveals Links to Adult Stem Cells

Journal of Histochemistry and Cytochemistry — Sat, 20 Mar 2010 16:55:27 +0100

Axotrophin/MARCH-7 was first identified in mouse embryonic stem cells as a neural stem cell gene. Using the axotrophin/MARCH-7 null mouse, we discovered profound effects on T lymphocyte responses, including 8-fold hyperproliferation and 5-fold excess release of the stem cell cytokine leukemia inhibitory factor (LIF). Our further discovery that axotrophin/MARCH-7 is required for targeted degradation of the LIF receptor subunit gp190 implies a direct role in the regulation of LIF signaling. Bioinformatics studies revealed a highly conserved RING-CH domain in common with the MARCH family of E3-ubiquitin ligases, and accordingly, axotrophin was renamed "MARCH-7." To probe protein expression of human axotrophin/MARCH-7, we prepared antibodies against different domains of the protein. Each antib...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Proteomic Analysis of Plasma from Patients Undergoing Coronary Artery Bypass Grafting Reveals a Protease/Antiprotease Imbalance in Favor of the Serpin α1-Antichymotrypsin

Journal of Proteome Research — Sat, 20 Mar 2010 10:06:45 +0100

Journal of Proteome Research, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable). (Source: Journal of Proteome Research)

An Unprecedented Biogenetic-Type Chemical Synthesis of 1(15→11) Abeotaxanes from Normal Taxanes

Journal of Natural Products — Sat, 20 Mar 2010 10:05:32 +0100

Journal of Natural Products, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable). (Source: Journal of Natural Products)

X-ray Crystallographic Analyses of Pig Pancreatic α-Amylase with Limit Dextrin, Oligosaccharide, and α-Cyclodextrin

Biochemistry — Sat, 20 Mar 2010 10:01:27 +0100

Biochemistry, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable). (Source: Biochemistry)

Stabilized 111In-Labeled sCCK8 Analogues for Targeting CCK2-Receptor Positive Tumors: Synthesis and Evaluation

Bioconjugate Chemistry — Sat, 20 Mar 2010 10:01:17 +0100

Bioconjugate Chemistry, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable). (Source: Bioconjugate Chemistry)

The Same Kind Of Circadian Rhythms That Govern Human Sleep Control Cell Division In Cyanobacteria

Biology / Biochemistry News From Medical News Today — Sat, 20 Mar 2010 07:00:00 +0100

A team of researchers at MIT and the University of California at San Diego has shown how cell division in a type of bacteria known as cyanobacteria is controlled by the same kind of circadian rhythms that govern human sleep patterns... (Source: Biology / Biochemistry News From Medical News Today)

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

'Glow-In-The-Dark' Sperm Sheds Light On Sexual Selection

Biology / Biochemistry News From Medical News Today — Sat, 20 Mar 2010 07:00:00 +0100

Previously unobservable events occurring between insemination and fertilization are the subject of a groundbreaking new article in Science magazine (March 18) by Mollie Manier, John Belote and Scott Pitnick, professors of biology in Syracuse University's College of Arts and Sciences... (Source: Biology / Biochemistry News From Medical News Today)

Cystic fibrosis is a risk factor for celiac disease.

Acta Biochim Pol — Sat, 20 Mar 2010 00:00:00 +0100

Conclusions: Genetic predisposition to celiac disease in cystic fibrosis patients is similar to that of the general population. However, our results suggest that cystic fibrosis is a risk factor for celiac disease development. PMID: 20300660 [PubMed - as supplied by publisher] (Source: Acta Biochim Pol)

Context Dependence of Trinucleotide Repeat Structures

Biochemistry — Fri, 19 Mar 2010 20:02:58 +0100

Biochemistry, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable). (Source: Biochemistry)

Crystallographic and Single-Crystal Spectral Analysis of the Peroxidase Ferryl Intermediate

Biochemistry — Fri, 19 Mar 2010 20:01:59 +0100

Biochemistry, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable). (Source: Biochemistry)

Biochemical Characterization of ThiT from Lactococcus lactis: A Thiamin Transporter with Picomolar Substrate Binding Affinity

Biochemistry — Fri, 19 Mar 2010 19:57:37 +0100

Biochemistry, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable). (Source: Biochemistry)

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Possible Important Pair of Acidic Residues in Vesicular Acetylcholine Transporter

Biochemistry — Fri, 19 Mar 2010 12:32:36 +0100

Biochemistry, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable). (Source: Biochemistry)

Partial Steps of Charge Translocation in the Nonpumping N139L Mutant of Rhodobacter sphaeroides Cytochrome c Oxidase with a Blocked D-Channel

Biochemistry — Fri, 19 Mar 2010 12:31:20 +0100

Biochemistry, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable). (Source: Biochemistry)

An Exposed Cysteine Residue of Human Angiostatic Mini Tryptophanyl-tRNA Synthetase

Biochemistry — Fri, 19 Mar 2010 12:29:48 +0100

Biochemistry, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable). (Source: Biochemistry)

Protein Expression Profiles of Necrosis and Apoptosis Induced by 5-Fluoro-2′-deoxyuridine in Mouse Cancer Cells

Journal of Proteome Research — Fri, 19 Mar 2010 11:47:55 +0100

Journal of Proteome Research, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable). (Source: Journal of Proteome Research)

Analysis of the Ontogenetic Variation in the Venom Proteome/Peptidome of Bothrops jararaca Reveals Different Strategies to Deal with Prey

Journal of Proteome Research — Fri, 19 Mar 2010 10:04:14 +0100

Journal of Proteome Research, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable). (Source: Journal of Proteome Research)

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Enzymatic Kinetic Resolution of Silybin Diastereoisomers⊥

Journal of Natural Products — Fri, 19 Mar 2010 10:03:24 +0100

Journal of Natural Products, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable). (Source: Journal of Natural Products)

Multifunctional Polymer Neutralizes Both Biological And Chemical Weapons

Biology / Biochemistry News From Medical News Today — Fri, 19 Mar 2010 08:00:00 +0100

In an ongoing effort to mirror the ability of biological tissues to respond rapidly and appropriately to changing environments, scientists from the McGowan Institute for Regenerative Medicine have synthesized a single, multifunctional polymer material that can decontaminate both biological and chemical toxins. They described the findings recently in Biomaterials... (Source: Biology / Biochemistry News From Medical News Today)

'Flying Vaccinator': Can Genetically Engineered Mosquitoes Provide A New Strategy Against Malaria?

Biology / Biochemistry News From Medical News Today — Fri, 19 Mar 2010 07:00:00 +0100

Mosquitoes transmit infectious diseases to millions of people every year, including malaria for which there is no effective vaccine. New research published in Insect Molecular Biology reveals that mosquito genetic engineering may turn the transmitter into a natural 'flying vaccinator', providing a new strategy for biological control over the disease... (Source: Biology / Biochemistry News From Medical News Today)

Wnt signalling and the control of cellular metabolism.

The Biochemical Journal — Fri, 19 Mar 2010 05:16:03 +0100

Authors: Sethi JK, Vidal-Puig A At the cellular level, the biological processes of cell proliferation, growth arrest, differentiation and apoptosis are all tightly coupled to appropriate alterations in metabolic status. In the case of cell proliferation, this requires redirecting metabolic pathways to provide the fuel and basic components for new cells. Ultimately, the successful co-ordination of cell-specific biology with cellular metabolism underscores multicellular processes as diverse as embryonic development, adult tissue remodelling and cancer cell biology. The Wnt signalling network has been implicated in all of these areas. While each of the Wnt-dependent signalling pathways are being individually delineated in a range of experimental systems, our understanding of how they inte...

Boric acid as a protector against paclitaxel genotoxicity.

Acta Biochim Pol — Fri, 19 Mar 2010 00:00:00 +0100

Authors: Turkez H, Tatar A, Hacımuftuoglu A, Ozdemir E Paclitaxel (PAC) is an anticancer drug used for treatments of breast, ovarian and lung cancers. However, little data is available in the literature on its potential genotoxicity on healthy human cells. On the other hand, boron deficiency and supplementation exert important biological effects in human and animal tissues. The biological effects of dietary boron are defined, but its interaction with PAC is not known for therapeutic uses. The aim of the present study was to determine whether boric acid (BA) confer a protection against PAC genotoxicity. After the application of PAC (10 or 20 microg/l) and BA (2.5 or 5 mg/l), the genotoxic effects were assessed by sister chromatid exchange (SCE) and micronucleus (MN) tests in human...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

N-myc downstream regulated 1 gene and its place in the cellular machinery.

Acta Biochim Pol — Fri, 19 Mar 2010 00:00:00 +0100

Authors: Kitowska A, Pawełczyk T The exact function of the protein product of N-myc downstream regulated 1 gene (NDRG1) is unclear. Depending on the tissue type the NDRG1 protein is localized in the cytoplasm, nucleus, mitochondrion or membranes. Moreover, the expression of NDRG1 may be altered by several factors such as hypoxia, heavy metals, DNA damage, hormones, oncogene, and tumor-suppressor genes. A number of studies emphasize the role of NDRG1 in cancerogenesis. Presumably NDRG1 participates in angiogenesis, metastases, and mechanisms leading to anti-cancer drug resistance. This review summarizes current knowledge about the NDRG1 gene and the position of NDRG1 protein in the cellular machinery. The role of NDRG1 in cancer pathogenesis and its possible usefulness as a progno...

Cloning and characterization of the yak gene coding for calpastatin and in silico analysis of its putative product.

Acta Biochim Pol — Fri, 19 Mar 2010 00:00:00 +0100

Authors: Zhang L, Ma B, Wu J, Fei C, Yang L, Wan H The calcium-activated neutral proteases, mu- and m-calpain, along with their inhibitor, calpastatin, have been demonstrated to mediate a variety of Ca(2+)-dependent processes including signal transduction, cell proliferation, cell cycle progression, differentiation, apoptosis, membrane fusion, platelet activation and skeletal muscle protein degradation. The cDNA coding for yak calpastatin was amplified and cloned by RT-PCR to investigate and characterize the nucleotide/amino acid sequence and to predict structure and function of the calpastatin. The present study suggests that the yak calpastatin gene encodes a protein of 786 amino acids that shares 99 % sequence identity with the amino acid sequence of cattle calpastatin, and that the...

Enzymatic synthesis of theanine from glutamic acid gamma-methyl ester and ethylamine by immobilized Escherichia coli cells with gamma-glutamyltranspeptidase activity.

Amino Acids — Fri, 19 Mar 2010 00:00:00 +0100

Authors: Zhang F, Zheng QZ, Jiao QC, Liu JZ, Zhao GH Theanine (gamma-glutamylethylamide) is the main amino acid component in green tea. The demand for theanine in the food and pharmaceutical industries continues to increase because of its special flavour and multiple physiological effects. In this research, an improved method for enzymatic theanine synthesis is reported. An economical substrate, glutamic acid gamma-methyl ester, was used in the synthesis catalyzed by immobilized Escherichia coli cells with gamma-glutamyltranspeptidase (GGT) activity. The results show that GGT activity with glutamic acid gamma-methyl ester as substrate was about 1.2-folds higher than that with glutamine as substrate. Reaction conditions were optimized by using 300 mmol/l glutamic acid gamma-methyl ester...

Purification of recombinant growth hormone by clear native gels for conformational analyses: preservation of conformation and receptor binding.

Amino Acids — Fri, 19 Mar 2010 00:00:00 +0100

Authors: Chen WQ, Salmazo A, Myllykoski M, Sjöblom B, Bidlingmaier M, Pollak A, Baumgärtel P, Djinovic-Carugo K, Kursula P, Lubec G Most protein preparations require purification steps prior to biophysical analysis assessing protein stability, secondary structure and degree of folding. It was, therefore, the aim of this study to develop a system to separate and purify a protein from a commercially available medicinal product, recombinant human growth hormone (rhGH) and show preservation of conformation and function following the gel-based procedure. The rhGH was run on clear native (CN) gels and recovered from the gels by electroelution using D-Tube Dialyzer Midi under rigorous cooling. Melting point studies indicated preservation of the structural integrity. This finding was...

Tanshinone IIA enhances BMP-2-stimulated commitment of C2C12 cells into osteoblasts via p38 activation.

Amino Acids — Fri, 19 Mar 2010 00:00:00 +0100

In conclusion, tanshinone IIA enhances the commitment of C2C12 cells into osteoblasts and their differentiation through synergistic cross talk between tanshinone IIA-induced p38 activation and BMP-2-induced Smad activation. These activations could subsequently induce the activation of Runx2, which induces osteogenesis via regulation of the osteogenic factors BMP and ALP expression. PMID: 20300786 [PubMed - as supplied by publisher] (Source: Amino Acids)

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Utilization of amino acids by bacteria from the pig small intestine.

Amino Acids — Fri, 19 Mar 2010 00:00:00 +0100

This study determined the utilization of amino acids (AA) by bacteria from the lumen of the pig small intestine. Digesta samples from different segments of the small intestine were inoculated into media containing 10 mmol/L each of select AA (L: -lysine, L: -threonine, L: -arginine, L: -glutamate, L: -histidine, L: -leucine, L: -isoleucine, L: -valine, L: -proline, L: -methionine, L: -phenylalanine or L: -tryptophan) and incubated for 24 h. The previous 24-h culture served as an inoculum for a subsequent 24-h subculture during each of 30 subcultures. Results of the in vitro cultivation experiment indicated that the 24-h disappearance rates for lysine, arginine, threonine, glutamate, leucine, isoleucine, valine or histidine were 50-90% in the duodenum, jejunum or ileum groups. After 30 subc...

Gluten T cell epitope targeting by TG3 and TG6; implications for dermatitis herpetiformis and gluten ataxia.

Amino Acids — Fri, 19 Mar 2010 00:00:00 +0100

Authors: Stamnaes J, Dorum S, Fleckenstein B, Aeschlimann D, Sollid LM Transglutaminase 2 (TG2) is well characterized as the main autoantigen of celiac disease. The ability of TG2 to deamidate and crosslink gluten peptides is essential for the gluten-dependent production of TG2 specific autoantibodies. In patients with primarily extraintestinal manifestation of gluten sensitivity the repertoire of autoantibodies may be different. In dermatitis herpetiformis (DH), TG3 appears to be the target autoantigen whereas in gluten ataxia (GA) autoantibodies reactive with TG6 are present. A functional role for TG3 and TG6 in these diseases has yet to be described. It is also not known whether these enzymes can use gluten peptides implicated in the pathology as substrates. We here report that simi...

Use of the Burrows-Wheeler similarity distribution to the comparison of the proteins.

Amino Acids — Fri, 19 Mar 2010 00:00:00 +0100

Authors: Yang L, Chang G, Zhang X, Wang T In this paper, we present an approach based on Burrows-Wheeler transform to compare the protein sequences. The strings representing amino acid sequences do not reflect the chemical physical properties better, and it is very hard to extract any key features by reading these long character strings directly. The use of the Burrows-Wheeler similarity distribution needs a suitable representation which can reflect some interesting properties of the proteins. For the comparison of the primary protein sequences we convert the protein sequences into digital codes by the Ponnuswamy hydrophobicity index, and for the comparison of the structure of the proteins we adjust the topology of protein structure strings, which are simple but useful representation o...

Iron binding activity of human iron-sulfur cluster assembly protein hIscA-1

BJ Energy — Fri, 19 Mar 2010 00:00:00 +0100

A human homologue of the iron-sulfur cluster assembly protein IscA (hIscA1) has been cloned and expressed in Escherichia coli cells. The UV-visible absorption and EPR (electron paramagnetic resonance) measurements reveal that hIscA1 purified from E. coli cells contains a mononuclear iron center and that the iron binding in hIscA1 expressed in E. coli cells can be further modulated by the iron content in the cell growth medium. Additional studies show that purified hIscA1 binds iron with an iron association constant of approx. 2.0 x 1019 M-1, and that the iron-bound hIscA1 is able to provide the iron for the iron-sulfur cluster assembly in a proposed scaffold protein IscU of E. coli in vitro. The complementation experiments indicate that hIscA1 can partially substitute for IscA in restoring...

On the conformations and properties of the L-tryptophyl-containing peptides in solution, depending of the pH - theoretical study vs. experiments

Biopolymers — Fri, 19 Mar 2010 00:00:00 +0100

The conformational preference and electronic properties of three L-tryptophyl-containing dipeptides, i.e. glycyl-L-tryptophane (H-Gly-Trp-OH), L-alanyl-L-tryptophane (H-Ala-Trp-OH) and L-methionyl-L-tryptophane (L-Met-Trp-OH) in solution depending on the pH of the media are studied both theoretically and experimentally. The effect of the protonation of the COO- and deprotonation of the NH3+ as well as the alkaline hydrolysis of the amide fragment in a strong basic media on the electronic spectra are discussed. Ab initio and DFT methods as well as the time-dependent DFT (TD-DFT) method as a function of the basis set are performed with a view to obtain the geometry and electronic properties of all of the species as well as the intermediate, obtained in the alkaline hydrolysis mechanism. © 2...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Diarylheptanoid from Pleuranthodium racemigerum with in Vitro Prostaglandin E2 Inhibitory and Cytotoxic Activity

Journal of Natural Products — Thu, 18 Mar 2010 18:39:32 +0100

Journal of Natural Products, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable). (Source: Journal of Natural Products)

The Discovery of Novel Experimental Therapies for Inflammatory Arthritis

Mediators of Inflammation — Thu, 18 Mar 2010 16:18:55 +0100

Conventional and biologic disease-modifying antirheumatic drugs have revolutionized the medical therapy of inflammatory arthritis. However, it remains unclear as to what can be done to treat immune-mediated chronic inflammation after patients become refractory to these therapies or develop serious side-effects and/or infections forcing drug withdrawal. Because of these concerns it is imperative that novel targets be continuously identified and experimental strategies designed to test potential arthritis interventions in vitro, but more importantly, in well-validated animal models of inflammatory arthritis. Over the past few years, sphingosine-1-phosphate, interleukin-7 receptor, spleen tyrosine kinase, extracellular signal-regulated kinase, mitogen-activated protein kinase 5/p38 kinase reg...

Proteomic Analysis Reveals Virus-Specific Hsp25 Modulation in Cardiac Myocytes

Journal of Proteome Research — Thu, 18 Mar 2010 14:19:48 +0100

Journal of Proteome Research, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable). (Source: Journal of Proteome Research)

Structural Characterization of Glycans on Omega-1, a Major Schistosoma mansoni Egg Glycoprotein That Drives Th2 Responses

Journal of Proteome Research — Thu, 18 Mar 2010 14:19:26 +0100

Journal of Proteome Research, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable). (Source: Journal of Proteome Research)

Increasing Understanding Of Drug Metabolism Provides Key Knowledge About Drug Toxicity And Effectiveness

Biology / Biochemistry News From Medical News Today — Thu, 18 Mar 2010 13:00:00 +0100

Research led by Wayne L... (Source: Biology / Biochemistry News From Medical News Today)

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Identification Of Key Mechanism That Guides Cells To Form Heart Tissue

Biology / Biochemistry News From Medical News Today — Thu, 18 Mar 2010 13:00:00 +0100

Researchers at the Keck School of Medicine of the University of Southern California (USC) have identified a key cellular mechanism that guides embryonic heart tissue formation - a process which, if disrupted, can lead to a number of common congenital heart defects... (Source: Biology / Biochemistry News From Medical News Today)

The Molecular Basis Of Detecting Tissue-Damaging Chemicals Goes Back More 500 Million Years

Biology / Biochemistry News From Medical News Today — Thu, 18 Mar 2010 13:00:00 +0100

Whenever you choke on acrid cigarette smoke, feel like you're burning up from a mouthful of wasabi-laced sushi, or cry while cutting raw onions and garlic, your response is being triggered by a primordial chemical sensor conserved across some 500 million years of animal evolution, report Brandeis University scientists in a study in Nature this week... (Source: Biology / Biochemistry News From Medical News Today)

Multimethodological Approach to Identification of Glycoproteins from the Proteome of Francisella tularensis, an Intracellular Microorganism

Journal of Proteome Research — Thu, 18 Mar 2010 10:05:35 +0100

Journal of Proteome Research, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable). (Source: Journal of Proteome Research)

Book Review of The Science of Chocolate

Journal of Natural Products — Thu, 18 Mar 2010 10:04:26 +0100

Journal of Natural Products, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable). (Source: Journal of Natural Products)

Coordinated Chromatin Control: Structural and Functional Linkage of DNA and Histone Methylation

Biochemistry — Thu, 18 Mar 2010 10:00:55 +0100

Biochemistry, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable). (Source: Biochemistry)

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

New Nanosized Biocompatible MR Contrast Agents Based on Lysine-Dendri-Graft Macromolecules

Bioconjugate Chemistry — Thu, 18 Mar 2010 10:00:47 +0100

Bioconjugate Chemistry, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable). (Source: Bioconjugate Chemistry)

Salt-Induced Gelation of Globular Protein Aggregates: Structure and Kinetics.

Biomacromolecules — Thu, 18 Mar 2010 00:00:00 +0100

Authors: Ako K, Nicolai T, Durand D Aggregates of the globular protein beta-lactoglobulin were formed by heating solutions of native proteins at pH 7, after which gels were formed by the addition of salt. The second step does not necessitate elevated temperatures and is therefore often called cold gelation. The structure of the gels was studied during their formation using light scattering and turbidity. Complementary confocal laser scanning microscopy measurements were done. We compared the structure with that of gels formed by heating native beta-lactoglobulin under the same conditions. Whereas in the latter case, microphase separation occurs above 0.2 M NaCl, no microphase separation was observed during cold gelation up to at least 1 M NaCl. The dependence of the kinetics and the fi...

The human lactoferrin-derived peptide hLF1-11 primes monocytes for an enhanced TLR-mediated immune response.

Biometals — Thu, 18 Mar 2010 00:00:00 +0100

In conclusion, monocytes were primed by hLF1-11 for an enhanced inflammatory response upon TLR4, TLR5, and TLR7 stimulation, but not TLR2 stimulation. Such effects of hLF1-11 on monocyte reactivity should be taken into account when considering the clinical development of this peptide for a therapeutic intervention in patients. PMID: 20238236 [PubMed - as supplied by publisher] (Source: Biometals)

Substrate Conformations Set the Rate of Enzymatic Acrylation by Lipases.

Chembiochem — Thu, 18 Mar 2010 00:00:00 +0100

Authors: Syrén PO, Hult K Acrylates represent a class of alpha,beta-unsaturated compounds of high industrial importance. We investigated the influence of substrate conformations on the experimentally determined reaction rates of the enzyme-catalysed transacylation of methyl acrylate and derivatives by ab initio DFT B3LYP calculations and molecular dynamics simulations. The results supported a least-motion mechanism upon the sp(2) to sp(3) substrate transition to reach the transition state in the enzyme active site. This was in accordance with our hypothesis that acrylates form productive transition states from their low-energy s-sis/s-trans conformations. Apparent k(cat) values were measured for Candida antarctica lipase B (CALB), Humicola insolens cutinase and Rhizomucor miehei l...

RNA-Cleaving Deoxyribozyme Sensor for Nucleic Acid Analysis: The Limit of Detection.

Chembiochem — Thu, 18 Mar 2010 00:00:00 +0100

This study contributes to the understanding of the factors responsible for the limit of detection (LOD) of RNA-cleaving deoxyribozyme sensors. A new sensor that detects specific DNA/RNA sequences was designed from deoxyribozyme OA-II [Chiuman, W.; Li, Y. (2006) J. Mol. Biol. 357, 748-754]. The sensor architecture allows for a unique combination of high selectivity, low LOD and the convenience of fluorescent signal monitoring in homogeneous solution. The LOD of the sensor was found to be ~1.6x10(-10) M after 3 h of incubation. An equation that allows estimation of the lowest theoretical LOD using characteristics of parent deoxyribozymes and their fluorogenic substrates was derived and experimentally verified. According to the equation, "catalytically perfect" enzymes can serve as scaffolds ...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

RNA Grooves Can Accommodate Disulfide-Bridged Bundles of alpha-Helical Peptides.

Chembiochem — Thu, 18 Mar 2010 00:00:00 +0100

Authors: Hyun S, Na J, Lee SJ, Park S, Yu J PMID: 20301162 [PubMed - as supplied by publisher] (Source: Chembiochem)

Mechanisms of RNA Degradation by the Eukaryotic Exosome.

Chembiochem — Thu, 18 Mar 2010 00:00:00 +0100

Authors: Tomecki R, Drazkowska K, Dziembowski A PMID: 20301164 [PubMed - as supplied by publisher] (Source: Chembiochem)

Photocaged T7 RNA Polymerase for the Light Activation of Transcription and Gene Function in Pro- and Eukaryotic Cells.

Chembiochem — Thu, 18 Mar 2010 00:00:00 +0100

Authors: Chou C, Young DD, Deiters A A light-activatable bacteriophage T7 RNA polymerase (T7RNAP) has been generated through the site-specific introduction of a photocaged tyrosine residue at the crucial position Tyr639 within the active site of the enzyme. The photocaged tyrosine disrupts polymerase activity by blocking the incoming nucleotide from reaching the active site of the enzyme. However, a brief irradiation with nonphototoxic UV light of 365 nm removes the ortho-nitrobenzyl caging group from Tyr639 and restores the RNA polymerase activity of T7RNAP. The complete orthogonality of T7RNAP to all endogenous RNA polymerases in pro- and eukaryotic systems allowed for the photochemical activation of gene expression in bacterial and mammalian cells. Specifically, E. coli cells were e...

Images Come to Life.

Chembiochem — Thu, 18 Mar 2010 00:00:00 +0100

Authors: Ratner T, Keinan E PMID: 20301168 [PubMed - as supplied by publisher] (Source: Chembiochem)

[beta]-sheet aggregation of kisspeptin-10 is stimulated by heparin but inhibited by amphiphiles

Biopolymers — Thu, 18 Mar 2010 00:00:00 +0100

The murine 10-residue neurohormone kisspeptin (YNWNSFGLRY) is an important regulator of reproductive behavior and gonadotrophin secretion. It is known to form a random coil in solution, but undergoes a structural change in the presence of membranes although the nature of this change is not fully determined. The peptide's conformational versatility raises the question whether it is also able to form ordered aggregates under physiological conditions, which might be relevant as a storage mechanism. Here we show that heparin induces kisspeptin to form [beta]-sheet rich amyloid aggregates both at neutral (pH 7.0) and slightly acidic (pH 5.2) conditions. Addition of heparin leads to aggregation after a certain lag phase, irrespective of the time of addition of heparin, indicating that heparin is...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Particle trapping using dielectrophoretically patterned carbon nanotubes

Electrophoresis — Thu, 18 Mar 2010 00:00:00 +0100

This study presents the dielectrophoretic (DEP) assembly of multi-walled carbon nanotubes (MWCNTs) between curved microelectrodes for the purpose of trapping polystyrene microparticles within a microfluidic system. Under normal conditions, polystyrene particles exhibit negative DEP behaviour and are repelled from microelectrodes. Interestingly, the addition of MWCNTs to the system alters this situation in two ways: first, they coat the surface of particles and change their dielectric properties to exhibit positive DEP behaviour; second, the assembled MWCNTs are highly conductive and after the deposition serve as extensions to the microelectrodes. They establish an array of nanoelectrodes that initiates from the edge of microelectrodes and grow along the electric field lines. These nanoelec...

Continuous dielectrophoretic separation of particles in a spiral microchannel

Electrophoresis — Thu, 18 Mar 2010 00:00:00 +0100

This article introduces a novel particle separation technique in DC electrokinetic flow through a planar double-spiral microchannel. The continuous separation arises from the cross-stream dielectrophoretic motion of particles induced by the non-uniform electric field inherent to curved channels. Specifically, particles are focused by DEP to one sidewall of the first spiral, and then dielectrophoretically deflected toward the other sidewall of the second spiral at a particle-dependent rate, leading to focused particle streams along different flow paths. This DEP-based particle separation technique is demonstrated in an asymmetric double-spiral microchannel by continuously separating a mixture of 5/10 [mu]m particles and 3/5 [mu]m particles. (Source: Electrophoresis)

Improved sample preparation method for glycan analysis of glycoproteins by CE-LIF and CE-MS

Electrophoresis — Thu, 18 Mar 2010 00:00:00 +0100

CE is a high-resolution separation technique broadly used in the biotechnology industry for carbohydrate analysis. The standard sample preparation protocol for CE analysis of glycans released from glycoproteins generally requires derivatization times of overnight at 37°C, using [ge]100 fold excess of fluorophore reagent, 8-aminopyrene-1,3,6-trisulfonic-acid, if the sample is unknown, or it is a regulated biotherapeutic product, possibly containing terminal sialic acid(s). In this paper, we report on significant improvements for the standard CE sample preparation method of glycan analysis. By replacing the conventionally used acetic acid catalyst with citric acid, as low as 1:10 glycan to fluorophore molar ratio (versus the typical 1:[ge]100 ratio) maintained the >95% derivatization yield ...

Pumpless dispensing of a droplet by breaking up a liquid bridge formed by electric induction

Electrophoresis — Thu, 18 Mar 2010 00:00:00 +0100

In this study, a new method is suggested and demonstrated for dispensing a droplet on the top plate with an inverted geometry by using electric field. The process of dispensing droplets consists of two stages: (i) formation of liquid bridge by moving up the charged fluid mass using the electrostatic force between the charges on the fluid mass and the induced charges on the substrate and (ii) its break-up by the motion of the top plate. Different from conventional electrohydrodynamic methods, electric induction enables the droplets to be dispensed on various surfaces including non-conducting substrate. The use of capillarity with an inverted geometry removes the need of external pumps or elaborates control for constant flow feed. The droplet diameter has been characterized as a function of ...

C-terminal domain phosphorylation of ERK3 controlled by Cdk1 and Cdc14 regulates its stability in mitosis

BJ Cell — Thu, 18 Mar 2010 00:00:00 +0100

Extracellular signal-regulated kinase 3 (ERK3) is an atypical mitogen-activated protein kinase that is suggested to play a role in cell cycle progression and cellular differentiation. However, it is not known if the function of ERK3 is regulated during the cell cycle. Here, we report that ERK3 is stoichiometrically hyperphosphorylated during entry into mitosis and is dephosphorylated at the M→G1 transition. The phosphorylation of ERK3 is associated with the accumulation of the protein in mitosis. In vitro phosphorylation of a series of ERK3 deletion mutants by mitotic cell extracts revealed that phosphorylation is confined to the unique C-terminal extension of the protein. Using mass spectrometry analysis, we identified four novel phosphorylation sites, Ser684, Ser688, Thr698 and Se...

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Purification and refolding of E.coli-expressed recombinant human interleukin-2

Biotechnology and Applied Biochemistry — Thu, 18 Mar 2010 00:00:00 +0100

The expression of recombinant human interleukin-2 (rhIL-2) in bacteria results in the formation of insoluble inclusion-body aggregates. These aggregates were first solubilized under denaturing conditions (solution of buffer phosphate containing 8 M urea and 10 mM mercaptoethanol) and then purified using immobilized metal affinity chromatography (IMAC). IMAC was used to capture rhIL-2. The protein was gradually refolded on the column by a gradient elution (8 M to 0 M urea) in the presence of 10% glycerol. Glycerol was used to abolish the protein aggregation during the refolding step. By this method, rhIL-2 was collected at 97% purity and its activity was measured by the lymphocyte transformation test (LTT). The measured activity was identical to commercial human interleukin-2. (Source: Biot...

Optimizing Performance of Glycopeptide Capture for Plasma Proteomics

Journal of Proteome Research — Wed, 17 Mar 2010 17:05:30 +0100

Journal of Proteome Research, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable). (Source: Journal of Proteome Research)

Editorial Board

FEBS Letters — Wed, 17 Mar 2010 16:26:11 +0100

(Source: FEBS Letters)

Book Review of The Chemistry of Fragrances. From Perfumer to Consumer

Journal of Natural Products — Wed, 17 Mar 2010 15:08:27 +0100

Journal of Natural Products, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable). (Source: Journal of Natural Products)

Book Review of Molecules and Medicine

Journal of Natural Products — Wed, 17 Mar 2010 15:07:58 +0100

Journal of Natural Products, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable). (Source: Journal of Natural Products)

MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.

Antitrypanosomal Cyclic Polyketide Peroxides from the Australian Marine Sponge Plakortis sp

Journal of Natural Products — Wed, 17 Mar 2010 14:44:09 +0100

Journal of Natural Products, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable). (Source: Journal of Natural Products)

Practically Useful: What the Rosetta Protein Modeling Suite Can Do for You

Biochemistry — Wed, 17 Mar 2010 14:40:34 +0100

Biochemistry, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable). (Source: Biochemistry)

Hydrogen Tunneling in Adenosylcobalamin-Dependent Glutamate Mutase: Evidence from Intrinsic Kinetic Isotope Effects Measured by Intramolecular Competition

Biochemistry — Wed, 17 Mar 2010 13:49:50 +0100

Biochemistry, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable). (Source: Biochemistry)

Peroxynitrite Induces Destruction of the Tetrahydrobiopterin and Heme in Endothelial Nitric Oxide Synthase: Transition from Reversible to Irreversible Enzyme Inhibition

Biochemistry — Wed, 17 Mar 2010 13:23:27 +0100

Biochemistry, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable). (Source: Biochemistry)