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111.
Hyaluronidase from rhesus monkey testes was purified by detergent extraction, ammonium sulphate fractionation, Sephadex G-200 column chromatography and concanavalin A-Sepharose affinity chromatography. The purified hyaluronidase showed one protein band on acrylamide gel electrophoresis. Antibodies to the purified hyaluronidase were raised in rabbits and showed a single precipitin line by Ouchterlony gel diffusion. The enzyme had a molecular weight of 62,000. The Km was 0.5 mg/ml for hydrolysis of hyaluronic acid at 37 degrees C. The optimum pH for the enzyme was 5.0 but activity was present over a broad pH range. The hyaluronidase was inhibited by HgCl2, CuSO4, FeSO4 and p-chloromercuribenzoate all at a concentration of 2 x 10(-4) M. Cysteine protected the enzyme against HgCl2 inhibition.  相似文献   
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113.
A role for alpha4 and beta7 integrins in mediating leucocyte entry into the central nervous system in the multiple sclerosis (MS)-like disease experimental autoimmune encephalomyelitis (EAE) has been demonstrated. However, the individual contributions of their respective ligands mucosal addressin cell adhesion molecule-1 (MAdCAM-1), vascular cell adhesion molecule-1 (VCAM-1) and E-cadherin expressed on the blood-brain barrier has not been determined. In the present paper, it is shown that an antibody directed against MAdCAM-1, the preferential ligand for alpha4beta7, effectively prevented the development of a progressive, non-remitting, form of EAE, actively induced by injection of myelin oligodendrocyte glycoprotein peptide (MOG(35-55)) autoantigen. Combinational treatment with both anti-MAdCAM-1, VCAM-1, and intercellular adhesion molecule-1 (ICAM-1) (ligand for integrin lymphocyte function-associated antigen (LFA)-1) mAbs led to more rapid remission than that obtained with anti-MAdCAM-1 antibody alone. However, neither MAdCAM-1 monotherapy, nor combinational antibody blockade was preventative when administered late in the course of disease progression. In conclusion, MAdCAM-1 plays a major contributory role in the progression of chronic EAE and is a potential therapeutic target for the treatment of MS. Critically, antivascular addressin therapy must be given early in the course of disease prior to the establishment of irreversible damage if it is to be effective, as a single treatment modality.  相似文献   
114.
A gene (apr 46) encoding a protease was cloned from Bacillus licheniformis RSP-09-37. It had an ORF of 1725 bp, encoding a pre-protein of 575 amino acids (63.2 kDa), which was functionally expressed and processed in E. coli JM 109. The mature protein, Apr 46, consists of 500 amino acids with a calculated molecular mass of 55 kDa. This protease shows 29-50% homology to known serine proteases and conserved domains. N-terminal sequencing suggests that Apr 46 protease is identical to a B. licheniformis RSP-09-37 protease, which is further supported by a similar stability in acetonitrile.  相似文献   
115.
RhoE function is regulated by ROCK I-mediated phosphorylation   总被引:7,自引:0,他引:7       下载免费PDF全文
The Rho GTPase family member RhoE regulates actin filaments partly by binding to and inhibiting ROCK I, a serine/threonine kinase that induces actomyosin contractility. Here, we show that ROCK I can phosphorylate multiple residues on RhoE in vitro. In cells, ROCK I-phosphorylated RhoE localizes in the cytosol, whereas unphosphorylated RhoE is primarily associated with membranes. Phosphorylation has no effect on RhoE binding to ROCK I, but instead increases RhoE protein stability. Using phospho-specific antibodies, we show that ROCK phosphorylates endogenous RhoE at serine 11 upon cell stimulation with platelet-derived growth factor, and that this phosphorylation requires an active protein kinase C signalling pathway. In addition, we demonstrate that phosphorylation of RhoE correlates with its activity in inducing stress fibre disruption and inhibiting Ras-induced transformation. This is the first demonstration of an endogenous Rho family member being phosphorylated in vivo and indicates that phosphorylation is an important mechanism to control the stability and function of this GTPase-deficient Rho protein.  相似文献   
116.
A thermophilic isolate Bacillus coagulans BTS-3 produced an extracellular alkaline lipase, the production of which was substantially enhanced when the type of carbon source, nitrogen source, and the initial pH of culture medium were consecutively optimized. Lipase activity 1.16 U/ml of culture medium was obtained in 48 h at 55 degrees C and pH 8.5 with refined mustard oil as carbon source and a combination of peptone and yeast extract (1:1) as nitrogen sources. The enzyme was purified 40-fold to homogeneity by ammonium sulfate precipitation and DEAE-Sepharose column chromatography. Its molecular weight was 31 kDa on SDS-PAGE. The enzyme showed maximum activity at 55 degrees C and pH 8.5, and was stable between pH 8.0 and 10.5 and at temperatures up to 70 degrees C. The enzyme was found to be inhibited by Al3+, Co2+, Mn2+, and Zn2+ ions while K+, Fe3+, Hg2+, and Mg2+ ions enhanced the enzyme activity; Na+ ions have no effect on enzyme activity. The purified lipase showed a variable specificity/hydrolytic activity towards various 4-nitrophenyl esters.  相似文献   
117.
Cell protrusions contribute to cell motility and migration by mediating the outward extension and initial adhesion of cell edges. In many cells, these extensions are supported by actin bundles assembled by the actin cross-linking protein, fascin. Multiple extracellular cues regulate fascin and here we focus on the mechanism by which the transmembrane proteoglycan, syndecan-1, specifically activates lamellipodial cell spreading and fascin-and-actin bundling when clustered either by thrombospondin-1, laminin, or antibody to the syndecan-1 extracellular domain. There is almost no knowledge of the signaling mechanisms of syndecan-1 cytoplasmic domain and we have tested the hypothesis that the unique V region of syndecan-1 cytoplasmic domain has a crucial role in these processes. By four criteria--the activities of N-cadherin/V region chimeras, syndecan-1 deletion mutants, or syndecan-1 point mutants, and specific inhibition by a membrane-permeable TAT-V peptide--we demonstrate that the V region is necessary and sufficient for these cell behaviors and map the molecular basis for its activity to multiple residues located across the V region. These activities correlate with a V-region-dependent incorporation of cell-surface syndecan-1 into a detergent-insoluble form. We also demonstrate functional roles of syndecan-1 V region in laminin-dependent C2C12 cell adhesion and three-dimensional cell migration. These data identify for the first time specific cell behaviors that depend on signaling through the V region of syndecan-1.  相似文献   
118.
A natural shift is taking place in the approaches being adopted by plant scientists in response to the accessibility of systems-based technology platforms. Metabolomics is one such field, which involves a comprehensive non-biased analysis of metabolites in a given cell at a specific time. This review briefly introduces the emerging field and a range of analytical techniques that are most useful in metabolomics when combined with computational approaches in data analyses. Using cases from Arabidopsis and other selected plant systems, this review highlights how information can be integrated from metabolomics and other functional genomics platforms to obtain a global picture of plant cellular responses. We discuss how metabolomics is enabling large-scale and parallel interrogation of cell states under different stages of development and defined environmental conditions to uncover novel interactions among various pathways. Finally, we discuss selected applications of metabolomics. This special review article is dedicated to the commemoration of the retirement of Dr. Oluf L. Gamborg after 25 years of service as Founding Managing Editor of Plant Cell Reports. RB and KN have contributed equally to this review.  相似文献   
119.
Background and objectiveCoronavirus 2019 (COVID-19) is caused by ‘severe acute respiratory syndrome coronavirus 2′ (SARS-CoV-2), first reported in Wuhan, China in December 2019, which eventually became a global disaster. Various key mediators have been reported in the pathogenesis of COVID-19. However, no effective pharmacological intervention has been available to combat COVID-19 complications. The present study screens nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN) as potential inhibitors of this present generation coronavirus infection using an in-silico approach.Materials and methodsThe SARS-CoV-2 proteins (nucleocapsid, proteases, post-fusion core, phosphatase, endoriboruclease) and ACE-2 protein were selected. The 2D structure of nicotinamide ribonucleoside and nicotinamide ribonucleotide was drawn using ChemDraw 14.0 and saved in .cdx format. The results were analyzed using two parameters: full fitness energy and binding free energy (ΔG).ResultsThe full fitness energy and estimated ΔG values from docking of NM, and NMN with selected SARS-CoV-2 target proteins, ADMET prediction and Target prediction indicate the interaction of NR and NMN in the treatment of COVID-19.ConclusionsBased on full fitness energy and estimated ΔG values from docking studies of NM and NAM with selected SARS-CoV-2 target proteins, ADME prediction, target prediction and toxicity prediction, we expect a possible therapeutic efficacy of NR in the treatment of COVID-19.Keyword: COVID-19, SARS-CoV-2, Molecular docking, Poly (ADP-ribose) polymerase enzyme, Nicotinamide  相似文献   
120.
Abstract: Diabetic encephalopathy, characterized by structural, electrophysiological, neurochemical, and cognitive abnormalities, is observed in insulin-dependent diabetes mellitus (IDDM) and non-IDDM (NIDDM). Identification of early biochemical lesions potentially may provide clues pointing to its pathogenesis. Insulin-like growth factors (IGFs) are neurotrophic factors that recently have been implicated in the pathogenesis of diabetic neuropathy. Because IGF-II is the predominant IGF in adult brain, we tested the hypothesis that IGF-II gene expression is decreased in the CNS in both IDDM and NIDDM. Brain and spinal cord were isolated from streptozotocin-diabetic rats, a model of IDDM with weight loss and impaired insulin production. IGF-II mRNA content was measured by northern and slot blots. After 2 weeks of diabetes, IGF-II mRNA content per milligram of tissue wet weight, as well as per unit of poly(A)+ RNA, declined significantly (p≤ 0.05) in brain and spinal cord. Insulin replacement therapy partially restored IGF-II mRNA levels in brain, cortex, medulla, and spinal cord. The obese, hyperinsulinemic, and spontaneously diabetic (fa/fa) Zucker rat was used as a model of NIDDM. Brain weight (p < 0.025) and IGF-II mRNA contents (p < 0.01) were significantly decreased in (fa/fa) versus lean nondiabetic (+/?) rats. Therefore, the decline in IGF-II mRNA levels in diabetic brain was independent of the type of diabetes, the direction of change in body weight, and the insulinemic state. We speculate that this early biochemical lesion may contribute to the development of diabetic encephalopathy.  相似文献   
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