MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'Research Letters in Biochemistry' source. Fri, 29 Apr 2011 00:21:10 +0100 http://www.medworm.com/index.php?rid=4527422&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fbcri%2F2011%2F164197.html Matrix-metalloproteinase-13 (MMP-13) has been shown to be an important protease in inflammatory and neoplastic conditions of the skeletal system. In particular, the stromal cells of giant cell tumor of bone (GCT) express very high levels of MMP-13 in response to the cytokine-rich environment of the tumor. We have previously shown that MMP-13 expression in these cells is regulated, at least in part, by the RUNX2 transcription factor. In the current study, we identify the expression of the c-Fos and c-Jun elements of the AP-1 transcription factor in these cells by protein screening assays and real-time PCR. We then used siRNA gene knockdown to determine that these elements, in particular c-Jun, are upstream regulators of MMP-13 expression and activity in GCT stromal cells. We conclude that t... Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=4527422 Mon, 28 Feb 2011 06:39:04 +0100 4527422 http://www.medworm.com/index.php?rid=4244565&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fbcri%2F2010%2F845975.html Marine environment has been the source of diverse life forms that produce different biologically active compounds. Marine organisms are consistently contributing with unparalleled bioactive compounds that have profound applications in nutraceuticals, cosmeceuticals, and pharmaceuticals. In this process, screening of natural products from marine organisms that could potentially inhibit the expression of metalloproteinases has gained a huge popularity, which became a hot field of research in life sciences. Metalloproteinases, especially, matrix metalloproteinases (MMPs) are a class of structurally similar enzymes that contribute to the extracellular matrix degradation and play major role in normal and pathological tissue remodeling. Imbalance in the expression of MMPs leads to severe patholo... Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=4244565 Fri, 10 Dec 2010 00:00:26 +0100 4244565 http://www.medworm.com/index.php?rid=4218750&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fbcri%2F2010%2F409640.html Due to the biochemical complexity of seminal fluid, we attempt to study the possible correlation between fructose, which is secreted under the effect of androgen hormone, and autoimmunity, which might play a role in varicocele associated infertility, in reducing sperm motility. Seminal fructose, antisperm antibodies (ASAs) and blood steroids hormones (testosterone and progesterone) levels were measured in 66 infertile males with varicocele and 84 without varicocele referred for fertility treatment. Seminal analysis was performed with biochemical measurements of seminal fructose and mixed agglutination reaction (MAR) for ASA. Serum levels of progesterone and testosterone were estimated using a competitive chemoluminescent enzyme immunoassay. The mean values for serum testosterone were 380.7... Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=4218750 Thu, 02 Dec 2010 06:06:41 +0100 4218750 http://www.medworm.com/index.php?rid=4212698&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fbcri%2F2011%2F191670.html MMP intervention strategies have met with limited clinical success due to severe toxicities. In particular, treatment with broad-spectrum MMP-inhibitors (MMPIs) caused musculoskeletal pain and inflammation. Selectivity may be essential for realizing the clinical potential of MMPIs. Here we review discoveries pinpointing membrane-bound MMPs as mediators of mechanisms underlying cancer and inflammation and as possible therapeutic targets for prevention/treatment of these diseases. We discuss strategies to target these therapeutic proteases using highly selective inhibitory agents (i.e., human blocking antibodies) against individual membrane-bound MMPs. (Source: Research Letters in Biochemistry) Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=4212698 Wed, 01 Dec 2010 01:40:02 +0100 4212698 http://www.medworm.com/index.php?rid=4212697&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fbcri%2F2011%2F630319.html In conclusion, our data provide a novel mechanism for MMP-28 function in cells in which furin serves as an intermolecular chaperone. (Source: Research Letters in Biochemistry) Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=4212697 Wed, 01 Dec 2010 01:40:02 +0100 4212697 http://www.medworm.com/index.php?rid=4055254&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fbcri%2F2010%2F213936.html Using molecular dynamics simulation, we study the evaporation of water molecules off partially solvated ubiquitin. The evaporation and cooling rates are determined for a molecule at the initial temperature of 300 K. The cooling rate is found to be around 3 K/ns, and decreases with water temperature in the course of the evaporation. The conformation changes are monitored by studying a variety of intermediate partially solvated ubiquitin structures. We find that ubiquitin shrinks with decreasing hydration shell and exposes more of its hydrophilic surface area to the surrounding. (Source: Research Letters in Biochemistry) Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=4055254 Mon, 11 Oct 2010 17:46:33 +0100 4055254 http://www.medworm.com/index.php?rid=4035578&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fbcri%2F2011%2F195209.html At a first glance, ribosome biogenesis and chromatin remodeling are quite different processes, but they share a common problem involving interactions between charged nucleic acids and small basic proteins that may result in unwanted intracellular aggregations. The multifunctional nuclear acidic chaperone NPM1 (B23/nucleophosmin) is active in several stages of ribosome biogenesis, chromatin remodeling, and mitosis as well as in DNA repair, replication and transcription. In addition, NPM1 plays an important role in the Myc-ARF-p53 pathway as well as in SUMO regulation. However, the relative importance of NPM1 in these processes remains unclear. Provided herein is an update on the expanding list of the diverse activities and interacting partners of NPM1. Mechanisms of NPM1 nuclear export func... Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=4035578 Wed, 06 Oct 2010 21:18:42 +0100 4035578 http://www.medworm.com/index.php?rid=4017501&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fbcri%2F2011%2F721463.html Alzheimer's disease is a neurodegenerative condition characterized by an accumulation of toxic amyloid beta- (Aβ-)peptides in the brain causing progressive neuronal death. Aβ-peptides are produced by aspartyl proteinase-mediated cleavage of the larger amyloid precursor protein (APP). In contrast to this detrimental “amyloidogenic” form of proteolysis, a range of zinc metalloproteinases can process APP via an alternative “nonamyloidogenic” pathway in which the protein is cleaved within its Aβ region thereby precluding the formation of intact Aβ-peptides. In addition, other members of the zinc metalloproteinase family can degrade preformed Aβ-peptides. As such, the zinc metalloproteinases, collectively, are key to downregulating ... Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=4017501 Thu, 30 Sep 2010 21:16:56 +0100 4017501 http://www.medworm.com/index.php?rid=4011340&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fbcri%2F2010%2F361387.html Conclusions. We demonstrated that plasma total homocysteine level (tHcy) is increased in BD and correlated with disease activity. No association was found between homocysteine levels and clinical involvement. (Source: Research Letters in Biochemistry) Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=4011340 Wed, 29 Sep 2010 20:11:24 +0100 4011340 http://www.medworm.com/index.php?rid=3972325&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fbcri%2F2010%2F549572.html The aminotransferase gene family in the model plant Arabidopsis thaliana consists of 44 genes. Twenty six of these enzymes are classified as characterized meaning that the reaction(s) that the enzyme catalyzes are documented using experimental means. The remaining 18 enzymes are uncharacterized and are therefore deemed putative. Our laboratory is interested in elucidating the function(s) of the remaining putative aminotransferase enzymes. To this end, we have identified and partially characterized an aminotransferase (TAT) enzyme from Arabidopsis annotated by the locus tag At5g36160. The full-length cDNA was cloned and the purified recombinant enzyme was characterized using in vitro and in vivo experiments. In vitro analysis showed that the enzyme is capable of interconverting L-Tyrosine a... Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=3972325 Thu, 16 Sep 2010 08:33:19 +0100 3972325 http://www.medworm.com/index.php?rid=3972324&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fbcri%2F2011%2F238601.html Heat-shock proteins (Hsps) are molecular chaperones that are ubiquitously expressed but are also induced in cells exposed to stressful stimuli. Hsps have been implicated in the induction and propagation of several diseases. This paper focuses on regulatory factors that control the transcription of the genes encoding Hsps. We also highlight how distinct transcription factors are able to interact and modulate Hsps in different pathological states. Thus, a better understanding of the complex signaling pathways regulating Hsp expression may lead to novel therapeutic targets. (Source: Research Letters in Biochemistry) Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=3972324 Thu, 16 Sep 2010 08:33:19 +0100 3972324 http://www.medworm.com/index.php?rid=3440296&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fbcri%2F2010%2F395758.html The cell wall teichuronic acid (TUA) of Micrococcus luteus is a long-chain polysaccharide composed of disaccharide repeating units [-4-β-D-ManNAcAp-(1→6)α-D-Glcp−1-]n, which is covalently anchored to the peptidoglycan on the inner cell wall and extended to the outer surface of the cell envelope. An enzyme complex responsible for the TUA chain biosynthesis was purified and characterized. The 440 kDa enzyme complex, named teichuronic acid synthetase (TUAS), is an octomer composed of two kinds of glycosyltransferases, Glucosyltransferase, and ManNAcA-transferase, which is capable of catalyzing the transfer of disaccharide glycosyl residues containing both glucose and the N-acetylmannosaminuronic acid residues. TUAS displays hydrophobic properties and is foun... Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=3440296 Tue, 06 Apr 2010 16:21:10 +0100 3440296 http://www.medworm.com/index.php?rid=3440295&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fbcri%2F2010%2F854656.html Ophthalmic mycoses caused by infectious fungi are being recognized as a serious concern since they lead to total blindness. Cephalosporium is one amongst several opportunistic fungal species implicated in ophthalmic infections leading to mycotic keratitis. A mitogenic lectin has been purified from the mycelia of fungus Cephalosporium, isolated from the corneal smears of a keratitis patient. Cephalosporium lectin (CSL) is a tetramer with subunit mass of 14 kDa, agglutinates human A, B, and O erythrocytes, and exhibits high affinity for mucin compared to fetuin and asialofetuin but does not bind to simple sugars indicating its complex sugar specificity. CSL showed strong binding to normal human peripheral blood mononuclear cells (PBMCs) to elicit mitogenic activity. The sugar specific... Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=3440295 Tue, 06 Apr 2010 16:21:10 +0100 3440295 http://www.medworm.com/index.php?rid=3398303&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fbcri%2F2010%2F516704.html We examined the impact of sevoflurane and isoflurane on the dimerization of human serum albumin (HSA), a protein with anesthetic binding sites that are well characterized. Intrinsic fluorescence emission was analyzed for spectral shifting and self-quenching, and control first derivatives (spectral responses to changes in HSA concentration) were compared against those obtained from samples treated with sevoflurane or isoflurane. Sevoflurane increased dimer-dependent self-quenching and both decreased oligomer-dependent spectral shifting, suggesting that inhaled anesthetics promoted HSA dimerization. Size exclusion chromatography and polarization data were consistent with these observations. The data support the proposed model of a reciprocal exchange of subdomains to form an HSA dimer. The o... Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=3398303 Wed, 24 Mar 2010 16:16:40 +0100 3398303 http://www.medworm.com/index.php?rid=3258188&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fbcri%2F2010%2F965716.html Phospholipids and lung surfactant proteins are known to be recycled within the lung alveolus mainly by uptake into type II epithelial cells that secrete lipid-enriched lung surfactant. Dipalmitoyl phosphatidylcholine (DPPC) is the major component of lung surfactant lipids and cholesterol is the second most abundant. However, cholesterol turnover in vivo has not been measured and it is not known how long steroidal compounds persist in the lung in intact animals. Here we report on experiments in which radiolabeled cholesterol was instilled into the lungs of rats, then at various postinstillation periods, radioactive sterols in lavage fluid, and in postlavage whole lungs were measured in individual animals. Radioactive sterols in the lungs remained high for a week and were still detectable 46... Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=3258188 Wed, 10 Feb 2010 16:22:35 +0100 3258188 http://www.medworm.com/index.php?rid=3039136&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fbcri%2F2010%2F489892.html The nitric oxide synthase-like protein from Bacillus cereus (bcNOS) has been cloned, expressed, and characterized. This small hemeprotein (356 amino acids in length) has a mass of 43 kDa and forms a dimer. The recombinant protein showed similar spectral shifts to the mammalian NOS proteins and could bind the substrates L-arginine and NG-hydroxy-L-arginine as well as the ligand imidazole. Low levels of activity were recorded for the hydrogen peroxide-dependent oxidation of NG-hydroxy-L-arginine and L-arginine by bcNOS, while a reconstituted system with the rat neuronal NOS reductase domain showed no activity. The recombinant bcNOS protein adds to the complement of bacterial NOS-like proteins that are used for the investigation of the mechanism and function of NO in microorganisms. (Source: ... Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=3039136 Mon, 30 Nov 2009 16:22:30 +0100 3039136 http://www.medworm.com/index.php?rid=2995244&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fbcri%2F2010%2F512056.html Ovine 6-phosphogluconate dehydrogenase (6PGD) is an enzyme of the pentose phosphate pathway, providing the necessary compounds of NADPH for the synthesis of fatty acids. Much of research has been conducted both on enzymatic level and on molecular level. However, to our knowledge, any correlation between enzymatic activity and 6PGD gene expression pattern related to different physiological stages has not been yet reported. With this report, we tried to highlight if any correlation between enzymatic activity and expression of ovine 6PGD gene exists, in respect to different milk yield. According to the determined enzymatic activities and adipocytes characteristics, ewes with low milk production possessed a greater (P≤.001) 6PGD activity and larger adipocytes than the highly productive ... Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=2995244 Mon, 16 Nov 2009 16:10:50 +0100 2995244 http://www.medworm.com/index.php?rid=2934095&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fbcri%2F2008%2F639829.html Clotting blood contains fibrin-bound thrombin, which is a major source of procoagulant activity leading to clot extension and further activation of coagulation. When bound to fibrin, thrombin is protected from inhibition by antithrombin (AT) + heparin but is neutralized when AT and heparin are covalently linked (ATH). Here, we report the surprising observation that, rather than yielding an inert complex, thrombin-ATH formation converts clots into anticoagulant surfaces that effectively catalyze inhibition of thrombin in the surrounding environment. (Source: Research Letters in Biochemistry) Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=2934095 Wed, 28 Oct 2009 16:00:39 +0100 2934095 http://www.medworm.com/index.php?rid=2934094&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fbcri%2F2008%2F801849.html Metabolic pulse-chase experiments demonstrated that 25-hydroxycholesterol (25-OH), the endogenous activator of the liver X receptor (LXR), significantly reduced the biosynthesis of phosphatidylethanolamine via CDP-ethanolamine (Kennedy) pathway at the step catalyzed by CTP: phosphoethanolamine cytidylyltransferase (Pcyt2). In the mouse embryonic fibroblasts C3H10T1/2, the LXR synthetic agonist TO901317 lowered Pcyt2 promoter-luciferase activity in a concentration-dependent manner. Furthermore, 25-OH and TO901317 reduced mouse Pcyt2 mRNA and protein levels by 35–60%. The inhibitory effects of oxysterols and TO901317 on the Pcyt2 promoter function, mRNA and protein expression were conserved in the human breast cancer cells MCF-7. These studies identify the Pcyt2 gene as a novel tar... Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=2934094 Wed, 28 Oct 2009 16:00:39 +0100 2934094 http://www.medworm.com/index.php?rid=2934093&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fbcri%2F2008%2F912478.html ABCC6 is a member of the adenosine triphosphate-binding cassette (ABC) gene subfamily C that encodes a protein (MRP6) involved in active transport of intracellular compounds to the extracellular environment. Mutations in ABCC6 cause pseudoxanthoma elasticum (PXE), an autosomal recessive disorder of the connective tissue characterized by progressive calcification of elastic structures in the skin, the eyes, and the cardiovascular system. MRP6 is codified by 31 exons and contains 1503 amino acids. In addition to a full-length transcript of ABCC6, we have identified an alternatively spliced variant of ABCC6 from a cDNA of human liver that lacks exons 19 and 24. The novel isoform was named ABCC6 Δ19Δ24. PCR analysis from cDNA of cell cultures of primary human hepatocites and embr... Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=2934093 Wed, 28 Oct 2009 16:00:39 +0100 2934093 http://www.medworm.com/index.php?rid=2934092&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fbcri%2F2009%2F256124.html The interaction between HIP family proteins (HIP1 and HIP12/1R) and clathrin is fundamental to endocytosis. We used circular dichroism (CD) to study the stability of an HIP1 subfragment (aa468-530) that is splayed open. CD thermal melts show HIP1 468-530 is only stable at low temperatures, but this HIP1 fragment contains a structural unit that does not melt out even at 83C∘. We then created HIP1 mutants to probe our hypothesis that a short hydrophobic path in the opened region is the binding site for clathrin light chain. We found that the binding of hub/LCb was sensitive to mutating two distantly separated basic residues (K474 and K494). The basic patches marked by K474 and K494 are conserved in HIP12/1R. The lack of conservation in sla2p (S. cerevisiae), HIP1 from D. melanogaster,... Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=2934092 Wed, 28 Oct 2009 16:00:39 +0100 2934092 http://www.medworm.com/index.php?rid=2934091&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fbcri%2F2009%2F960560.html We previously developed a highly specific method for detecting SNPs with a microarray-based system using stem-loop probes. In this paper we demonstrate that coupling a multiplexing procedure with our microarray method is possible for the simultaneous detection and genotyping of four point mutations, in three different genes, involved in Charcot-Marie-Tooth disease. DNA from healthy individuals and patients was amplified, labeled with Cy3 by multiplex PCR; and hybridized to microarrays. Spot signal intensities were 18 to 74 times greater for perfect matches than for mismatched target sequences differing by a single nucleotide (discrimination ratio) for “homozygous” DNA from healthy individuals. “Heterozygous” mutant DNA samples gave signal intensity ratios close to 1... Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=2934091 Wed, 28 Oct 2009 16:00:39 +0100 2934091 http://www.medworm.com/index.php?rid=2934090&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fbcri%2F2009%2F685342.html In the present study, we identified protein phosphatases dephosphorylating centrins previously phosphorylated by protein kinase CK2. The following phosphatases known to be present in the retina were tested: PP1, PP2A, PP2B, PP2C, PP5, and alkaline phosphatase. PP2C α and β were capable of dephosphorylating P-Thr138-centrin1 most efficiently. PP2Cδ was inactive and the other retinal phosphatases also had much less or no effect. Similar results were observed for centrins 2 and 4. Centrin3 was not a substrate for CK2. The results suggest PP2C α and β to play a significant role in regulating the phosphorylation status of centrins in vivo. (Source: Research Letters in Biochemistry) Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=2934090 Wed, 28 Oct 2009 16:00:39 +0100 2934090 http://www.medworm.com/index.php?rid=2934089&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fbcri%2F2009%2F151424.html The cholesterol-lowering drug fluvastatin (FS) has an inhibitory effect on the growth of the pathogenic yeast Candida albicans that is dependent on the pH of the medium. At the low pH value of the vagina, FS is growth inhibitory at low and at high concentrations, while at intermediate concentrations (1–10 mM), it has no inhibitory effect. Examination of the effect of the common antifungal drug fluconazole in combination with FS demonstrates drug interactions in the low concentration range. Determination of intracellular stress and the activity of the FS target enzyme HMG-CoA reductase confirm our hypothesis that in the intermediate dose range adjustments to the sterol biosynthesis pathway can compensate for the action of FS. We conclude that the pH dependent uptake of FS acros... Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=2934089 Wed, 28 Oct 2009 16:00:39 +0100 2934089 http://www.medworm.com/index.php?rid=2934088&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fbcri%2F2009%2F783035.html The acetylation mechanisms of several selected typical substrates from experiments, including arylamines and arylhydrazines, are investigated with the density functional theory in this paper. The results indicate that all the transition states are characterized by a four-membered ring structure, and hydralazine (HDZ) is the most potent substrate. The bioactivity for all the compounds is increased in a sequence of PABA≈4-AS<4-MA<5-AS≈INH<HDZ. The conjunction effect and the delocalization of the lone pairs of N atom play a key role in the reaction. All the results are consistent with the experimental data. (Source: Research Letters in Biochemistry) Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=2934088 Wed, 28 Oct 2009 16:00:39 +0100 2934088 http://www.medworm.com/index.php?rid=2934087&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Fbcri%2F2009%2F251731.html Hyaluronan (HA) is a linear polysaccharide of high molecular weight that exists as a component of the extracellular matrix. The larvae (leptocephali) of the Japanese conger eel (Anguilliformes: Conger myriaster) have high levels of hyaluronan (HA) which is thought to help control body water content. We isolated glycosaminoglycans (GAGs) from Japanese conger eel leptocephali and measured the changes in tissue HA content during metamorphosis. HA content decreased during metamorphosis. In contrast, neutral sugar content increased during metamorphosis. We hypothesize that the leptocephali utilize a metabolic pathway that converts HA to glucose during metamorphosis. Glucose may then be metabolized to glycogen and stored in the juvenile life-history stage. (Source: Research Letters in Biochemist... Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=2934087 Wed, 28 Oct 2009 16:00:39 +0100 2934087 http://www.medworm.com/index.php?rid=2678152&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Frlbc%2F2009%2F783035.html The acetylation mechanisms of several selected typical substrates from experiments, including arylamines and arylhydrazines, are investigated with the density functional theory in this paper. The results indicate that all the transition states are characterized by a four-membered ring structure, and hydralazine (HDZ) is the most potent substrate. The bioactivity for all the compounds is increased in a sequence of PABA≈4-AS<4-MA<5-AS≈INH<HDZ. The conjunction effect and the delocalization of the lone pairs of N atom play a key role in the reaction. All the results are consistent with the experimental data. (Source: Research Letters in Biochemistry) Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=2678152 Fri, 07 Aug 2009 12:08:42 +0100 2678152 http://www.medworm.com/index.php?rid=2678151&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Frlbc%2F2009%2F251731.html Hyaluronan (HA) is a linear polysaccharide of high molecular weight that exists as a component of the extracellular matrix. The larvae (leptocephali) of the Japanese conger eel (Anguilliformes: Conger myriaster) have high levels of hyaluronan (HA) which is thought to help control body water content. We isolated glycosaminoglycans (GAGs) from Japanese conger eel leptocephali and measured the changes in tissue HA content during metamorphosis. HA content decreased during metamorphosis. In contrast, neutral sugar content increased during metamorphosis. We hypothesize that the leptocephali utilize a metabolic pathway that converts HA to glucose during metamorphosis. Glucose may then be metabolized to glycogen and stored in the juvenile life-history stage. (Source: Research Letters in Biochemist... Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=2678151 Fri, 07 Aug 2009 12:08:42 +0100 2678151 http://www.medworm.com/index.php?rid=2673851&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Frlbc%2F2009%2F151424.html The cholesterol-lowering drug fluvastatin (FS) has an inhibitory effect on the growth of the pathogenic yeast Candida albicans that is dependent on the pH of the medium. At the low pH value of the vagina, FS is growth inhibitory at low and at high concentrations, while at intermediate concentrations (1–10 mM), it has no inhibitory effect. Examination of the effect of the common antifungal drug fluconazole in combination with FS demonstrates drug interactions in the low concentration range. Determination of intracellular stress and the activity of the FS target enzyme HMG-CoA reductase confirm our hypothesis that in the intermediate dose range adjustments to the sterol biosynthesis pathway can compensate for the action of FS. We conclude that the pH dependent uptake of FS acros... Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=2673851 Thu, 06 Aug 2009 12:11:23 +0100 2673851 http://www.medworm.com/index.php?rid=2601197&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Frlbc%2F2009%2F685342.abs.html In the present study, we identified protein phosphatases dephosphorylating centrins previously phosphorylated by protein kinase CK2. The following phosphatases known to be present in the retina were tested: PP1, PP2A, PP2B, PP2C, PP5, and alkaline phosphatase. PP2C α and β were capable of dephosphorylating P-Thr138-centrin1 most efficiently. PP2Cδ was inactive and the other retinal phosphatases also had much less or no effect. Similar results were observed for centrins 2 and 4. Centrin3 was not a substrate for CK2. The results suggest PP2C α and β to play a significant role in regulating the phosphorylation status of centrins in vivo. (Source: Research Letters in Biochemistry) Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=2601197 Wed, 15 Jul 2009 11:58:35 +0100 2601197 http://www.medworm.com/index.php?rid=2575822&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Frlbc%2F2009%2F960560.abs.html We previously developed a highly specific method for detecting SNPs with a microarray-based system using stem-loop probes. In this paper we demonstrate that coupling a multiplexing procedure with our microarray method is possible for the simultaneous detection and genotyping of four point mutations, in three different genes, involved in Charcot-Marie-Tooth disease. DNA from healthy individuals and patients was amplified, labeled with Cy3 by multiplex PCR; and hybridized to microarrays. Spot signal intensities were 18 to 74 times greater for perfect matches than for mismatched target sequences differing by a single nucleotide (discrimination ratio) for “homozygous” DNA from healthy individuals. “Heterozygous” mutant DNA samples gave signal intensity ratios close to 1... Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=2575822 Tue, 07 Jul 2009 11:58:25 +0100 2575822 http://www.medworm.com/index.php?rid=2575821&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Frlbc%2F2009%2F685342.html In the present study, we identified protein phosphatases dephosphorylating centrins previously phosphorylated by protein kinase CK2. The following phosphatases known to be present in the retina were tested: PP1, PP2A, PP2B, PP2C, PP5, and alkaline phosphatase. PP2C α and β were capable of dephosphorylating P-Thr138-centrin1 most efficiently. PP2Cδ was inactive and the other retinal phosphatases also had much less or no effect. Similar results were observed for centrins 2 and 4. Centrin3 was not a substrate for CK2. The results suggest PP2C α and β to play a significant role in regulating the phosphorylation status of centrins in vivo. (Source: Research Letters in Biochemistry) Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=2575821 Tue, 07 Jul 2009 11:58:25 +0100 2575821 http://www.medworm.com/index.php?rid=2503385&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Frlbc%2F2009%2F960560.html We previously developed a highly specific method for detecting SNPs with a microarray-based system using stem-loop probes. In this paper we demonstrate that coupling a multiplexing procedure with our microarray method is possible for the simultaneous detection and genotyping of four point mutations, in three different genes, involved in Charcot-Marie-Tooth disease. DNA from healthy individuals and patients was amplified, labeled with Cy3 by multiplex PCR; and hybridized to microarrays. Spot signal intensities were 18 to 74 times greater for perfect matches than for mismatched target sequences differing by a single nucleotide (discrimination ratio) for “homozygous” DNA from healthy individuals. “Heterozygous” mutant DNA samples gave signal intensity ratios close to 1... Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=2503385 Thu, 25 Jun 2009 08:45:46 +0100 2503385 http://www.medworm.com/index.php?rid=2467828&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Frlbc%2F2008%2F639829.html Clotting blood contains fibrin-bound thrombin, which is a major source of procoagulant activity leading to clot extension and further activation of coagulation. When bound to fibrin, thrombin is protected from inhibition by antithrombin (AT) + heparin but is neutralized when AT and heparin are covalently linked (ATH). Here, we report the surprising observation that, rather than yielding an inert complex, thrombin-ATH formation converts clots into anticoagulant surfaces that effectively catalyze inhibition of thrombin in the surrounding environment. (Source: Research Letters in Biochemistry) Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=2467828 Wed, 10 Jun 2009 02:22:48 +0100 2467828 http://www.medworm.com/index.php?rid=2467827&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Frlbc%2F2008%2F801849.html Metabolic pulse-chase experiments demonstrated that 25-hydroxycholesterol (25-OH), the endogenous activator of the liver X receptor (LXR), significantly reduced the biosynthesis of phosphatidylethanolamine via CDP-ethanolamine (Kennedy) pathway at the step catalyzed by CTP: phosphoethanolamine cytidylyltransferase (Pcyt2). In the mouse embryonic fibroblasts C3H10T1/2, the LXR synthetic agonist TO901317 lowered Pcyt2 promoter-luciferase activity in a concentration-dependent manner. Furthermore, 25-OH and TO901317 reduced mouse Pcyt2 mRNA and protein levels by 35–60%. The inhibitory effects of oxysterols and TO901317 on the Pcyt2 promoter function, mRNA and protein expression were conserved in the human breast cancer cells MCF-7. These studies identify the Pcyt2 gene as a novel tar... Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=2467827 Wed, 10 Jun 2009 02:22:48 +0100 2467827 http://www.medworm.com/index.php?rid=2467826&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Frlbc%2F2008%2F912478.html ABCC6 is a member of the adenosine triphosphate-binding cassette (ABC) gene subfamily C that encodes a protein (MRP6) involved in active transport of intracellular compounds to the extracellular environment. Mutations in ABCC6 cause pseudoxanthoma elasticum (PXE), an autosomal recessive disorder of the connective tissue characterized by progressive calcification of elastic structures in the skin, the eyes, and the cardiovascular system. MRP6 is codified by 31 exons and contains 1503 amino acids. In addition to a full-length transcript of ABCC6, we have identified an alternatively spliced variant of ABCC6 from a cDNA of human liver that lacks exons 19 and 24. The novel isoform was named ABCC6 Δ19Δ24. PCR analysis from cDNA of cell cultures of primary human hepatocites and embr... Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=2467826 Wed, 10 Jun 2009 02:22:48 +0100 2467826 http://www.medworm.com/index.php?rid=2467825&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2Fjournals%2Frlbc%2F2009%2F256124.html The interaction between HIP family proteins (HIP1 and HIP12/1R) and clathrin is fundamental to endocytosis. We used circular dichroism (CD) to study the stability of an HIP1 subfragment (aa468-530) that is splayed open. CD thermal melts show HIP1 468-530 is only stable at low temperatures, but this HIP1 fragment contains a structural unit that does not melt out even at 83C∘. We then created HIP1 mutants to probe our hypothesis that a short hydrophobic path in the opened region is the binding site for clathrin light chain. We found that the binding of hub/LCb was sensitive to mutating two distantly separated basic residues (K474 and K494). The basic patches marked by K474 and K494 are conserved in HIP12/1R. The lack of conservation in sla2p (S. cerevisiae), HIP1 from D. melanogaster,... Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=2467825 Wed, 10 Jun 2009 02:22:48 +0100 2467825 http://www.medworm.com/index.php?rid=1880899&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F912478 ABCC6 is a member of the adenosine triphosphate-binding cassette (ABC) gene subfamily C that encodes a protein (MRP6) involved in active transport of intracellular compounds to the extracellular environment. Mutations in ABCC6 cause pseudoxanthoma elasticum (PXE), an autosomal recessive disorder of the connective tissue characterized by progressive calcification of elastic structures in the skin, the eyes, and the cardiovascular system. MRP6 is codified by 31 exons and contains 1503 amino acids. In addition to a full-length transcript of ABCC6, we have identified an alternatively spliced variant of ABCC6 from a cDNA of human liver that lacks exons 19 and 24. The novel isoform was named ABCC6 Δ19Δ24. PCR analysis from cDNA of cell cultures of primary human hepatocites and embr... Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=1880899 Thu, 16 Oct 2008 15:44:14 +0100 1880899 http://www.medworm.com/index.php?rid=1618792&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F639829 Clotting blood contains fibrin-bound thrombin, which is a major source of procoagulant activity leading to clot extension and further activation of coagulation. When bound to fibrin, thrombin is protected from inhibition by antithrombin (AT) + heparin but is neutralized when AT and heparin are covalently linked (ATH). Here, we report the surprising observation that, rather than yielding an inert complex, thrombin-ATH formation converts clots into anticoagulant surfaces that effectively catalyze inhibition of thrombin in the surrounding environment. (Source: Research Letters in Biochemistry) Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=1618792 Mon, 14 Jul 2008 14:40:50 +0100 1618792 http://www.medworm.com/index.php?rid=1618791&cid=s_37729_60_f&fid=37729&url=http%3A%2F%2Fwww.hindawi.com%2FGetArticle.aspx%3Fdoi%3D10.1155%2F2008%2F801849 Metabolic pulse-chase experiments demonstrated that 25-hydroxycholesterol (25-OH), the endogenous activator of the liver X receptor (LXR), significantly reduced the biosynthesis of phosphatidylethanolamine via CDP-ethanolamine (Kennedy) pathway at the step catalyzed by CTP: phosphoethanolamine cytidylyltransferase (Pcyt2). In the mouse embryonic fibroblasts C3H10T1/2, the LXR synthetic agonist TO901317 lowered Pcyt2 promoter-luciferase activity in a concentration-dependent manner. Furthermore, 25-OH and TO901317 reduced mouse Pcyt2 mRNA and protein levels by 35–60%. The inhibitory effects of oxysterols and TO901317 on the Pcyt2 promoter function, mRNA and protein expression were conserved in the human breast cancer cells MCF-7. These studies identify the Pcyt2 gene as a novel tar... Research Letters in Biochemistry journals http://www.medworm.com/rss/comments.php?id=1618791 Mon, 14 Jul 2008 14:40:50 +0100 1618791