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91.
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Isoamylase production in batchwise and fed-batch cultures of Pseudomonas amyloderomosa (strain WU7211-2) was investigated. By feeding maltose in a mode motivated by its structure gene (iam), the final isoamylase activity of 5100 U/ml was achieved, as compared to 4100 U/ml in batch cultivation and 3800 U/ml in shaken flasks. The enhancement may be due to the fact that the production of isoamylase can be induced effectively by the maltose only if the glucose concentration is maintained below the inhibitory level. Also, cultivations based on 500-ml shaken flasks, performed with different amount of proteimax HE90, showed that higher amounts of proteimax HE90 resulted in an increased value of pH that had an adverse effect on isoamylase yield.The authors wish to thank the Food Industry Research and Development Institute (FIRDI), Taiwan, R.O.C for the financial support (Cooperative Agreement 94M904-2B). Appreciation is also extended to Drs. C.C. Liao, W.S. Chu and L.L. Lin of FIRDI for their valuable discussions. 相似文献
93.
Morphometric Analysis of Hepatocellular carcinomaLaiMao-de(来茂德);ChenPei-hui(陈培辉)andZhouShui-yun(周水云)(DepartmentofPathology,Zh... 相似文献
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Nathaniel M. Bachrach Wilmot B. Valhmu Enrico Stazzone Anthony Ratcliffe W. Michael Lai Van C. Mow 《Journal of biomechanics》1995,28(12):1561-1569
Explant loading experiments were conducted to investigate the effect of load duration on proteoglycan synthesis. A compressive load of 0.1 MPa applied for 10 min was found to stimulate proteoglycan synthesis, while the same load applied for 20 h suppressed synthesis. This bimodal response suggests that the cells are responding to different mechanical stimuli as time progresses. A theoretical model has therefore been developed to describe the mechanical environment perceived by cells within soft hydrated tissues (e.g. articular cartilage) while the tissue is being loaded. The cells are modeled, using the biphasic theory, as fluid-solid inclusions embedded in and attached to a biphasic extracellular matrix of distinct material properties. A method of solution is developed which is valid for any axisymmetric loading configuration, provided that the cell radius, a, is small relative to the tissue height, h (i.e. h/a 1). A closed-form analytical solution for this inclusion problem is then presented for the confined compression configuration. Results from this model show that the mechanical environment in and around the cells is time dependent and inhomogeneous, and can be significantly influenced by differences in properties between the cell and the extracellular matrix. 相似文献
96.
A number of vanadium compounds (vanadate, vanadyl sulfate, metavanadate) have insulin-mimicking actions bothin vitro andin vivo. They have multiple biological effects in cultured cells and interact directly with various enzymes. The inhibitory action on phosphoprotein tyrosine phosphatases (PTPs) and enhancement of cellular tyrosine phosphorylation appear to be the most relevant to explain the ability to mimic insulin. We demonstrated that in rat adipocytes both acute insulin effects, e.g. stimulation of IGF-II and transferrin binding and a chronic effect, insulin receptor downregulation, were stimulated by vanadate. Vanadate also enhanced insulin binding, particularly at very low insulin concentrations, associated with increased receptor affinity. This resulted in increased adipocyte insulin sensitivity. Finally vanadate augmented the extent of activation of the insulin receptor kinase by submaximal insulin concentrations. This was associated with a prolongation of the insulin biological response, lipogenesis, after removal of hormone.In conclusion: in rat adipocytes vanadate promotes insulin action by three mechanisms, 1) a direct insulin-mimetic action, 2) an enhancement of insulin sensitivity and 3) a prolongation of insulin biological response. These data suggest that PTP inhibitors have potential as useful therapeutic agents in insulin-resistant and relatively insulin-deficient forms of diabetes mellitus. 相似文献
97.
Hepatitis C virus core protein interacts with the cytoplasmic tail of lymphotoxin-beta receptor. 总被引:22,自引:2,他引:20 下载免费PDF全文
M Matsumoto T Y Hsieh N Zhu T VanArsdale S B Hwang K S Jeng A E Gorbalenya S Y Lo J H Ou C F Ware M M Lai 《Journal of virology》1997,71(2):1301-1309
Hepatitis C virus (HCV) core protein is a multifunctional protein. We examined whether it can interact with cellular proteins, thus contributing to viral pathogenesis. Using the HCV core protein as a bait to screen a human liver cDNA library in a yeast two-hybrid screening system, we have isolated several positive clones encoding cellular proteins that interact with the HCV core protein. Interestingly, more than half of these clones encode the cytoplasmic domain of lymphotoxin-beta receptor (LT betaR), which is a member of the tumor necrosis factor receptor family. Their binding was confirmed by in vitro glutathione S-transferase fusion protein binding assay and protein-protein blotting assay to be direct and specific. The binding sites were mapped within a 58-amino-acid region of the cytoplasmic tail of LT betaR. The binding site in the HCV core protein was localized within amino acid residues 36 to 91 from the N terminus, corresponding to the hydrophilic region of the protein. In mammalian cells, the core protein was found to be associated with the membrane-bound LT betaR. Since the LT betaR is involved in germinal center formation and developmental regulation of peripheral lymphoid organs, lymph node development, and apoptotic signaling, the binding of HCV core protein to LT betaR suggests the possibility that this viral protein has an immunomodulating function and may explain the mechanism of viral persistence and pathogenesis of HCV. 相似文献
98.
Division of Listeria monocytogenes serovar 4b strains into two groups by PCR and restriction enzyme analysis. 总被引:2,自引:2,他引:0 下载免费PDF全文
H Ericsson P Stlhandske M L Danielsson-Tham E Bannerman J Bille C Jacquet J Rocourt W Tham 《Applied microbiology》1995,61(11):3872-3874
Altogether, 133 strains of Listeria monocytogenes serovar 4b were investigated. A segment of 2,916 bp containing parts of the two genes inlA and inlB in L. monocytogenes was amplified by the PCR technique. The PCR product obtained was cleaved with the restriction enzyme AluI, and the fragments generated were separated by gel electrophoresis, leading to two distinct groups: PCR-restriction enzyme analysis groups I and II, containing 37 and 96 strains, respectively. The PCR-restriction enzyme analysis method described in this paper could be a useful tool for the subtyping of L. monocytogenes serovar 4b strains. 相似文献
99.
拉萨郊区藏族的指纹研究 总被引:2,自引:0,他引:2
本文报道了拉萨郊区517例(男226人,女291人)藏族健康人的指纹参数正常值、调查分析了指纹类型、指纹组合、指纹指数和指嵴纹计数。比较了藏族不同居群、不同民族和人种间的差异。结果表明,藏族有自己的指纹特点,又显著蒙古人种的一般特征。 相似文献
100.