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181.
S. Maheshkumar S. M. Goyal P. P. Economon 《Zeitschrift fur angewandte Ichthyologie》1991,7(2):115-119
A virus-adsorption-elution (viradel) method using electropositive microporous filters (Virosorb 1-MDS) was used for the concentration and détéction of infectious pancreatic necrosis virus (IPNV) at a hatchery with a past history of IPNV infection. Samples of fish tissue and unconcentrated water were also examined for the presence of IPNV. Virus was isolated from three of the nine concentrated water samples taken from various locations at the hatchery. Virus was also isolated from pooled fish tissues, but not from unconcentrated water samples. Representative numbers of viruses isolated from water and fish tissues were examined for virus neutralization in the presence of anti-IPNV amiserum; resistance to acid, ether, and heat; and replication in the presence of 5-bromo-2'-deoxyuridine (BUDR). When tested by dot-immunobinding assay using a panel of monoclonal antibodies (MABs), the viral isolates were found to belong to the West Buxton serotype of IPNV. 相似文献
182.
Chronic cardiac resynchronization therapy and reverse ventricular remodeling in a model of nonischemic cardiomyopathy 总被引:2,自引:0,他引:2
Nishijima Y Sridhar A Viatchenko-Karpinski S Shaw C Bonagura JD Abraham WT Joshi MS Bauer JA Hamlin RL Györke S Feldman DS Carnes CA 《Life sciences》2007,81(14):1152-1159
While cardiac resynchronization therapy (CRT) has been shown to reduce morbidity and mortality in heart failure (HF) patients, the fundamental mechanisms for the efficacy of CRT are poorly understood. The lack of understanding of these basic mechanisms represents a significant barrier to our understanding of the pathogenesis of HF and potential recovery mechanisms. Our purpose was to determine cellular mechanisms for the observed improvement in chronic HF after CRT. We used a canine model of chronic nonischemic cardiomyopathy. After 15 months, dogs were randomized to continued RV tachypacing (untreated HF) or CRT for an additional 9 months. Six minute walk tests, echocardiograms, and electrocardiograms were done to assess the functional response to therapy. Left ventricular (LV) midmyocardial myocytes were isolated to study electrophysiology and intracellular calcium regulation. Compared to untreated HF, CRT improved HF-induced increases in LV volumes, diameters and mass (p<0.05). CRT reversed HF-induced prolongations in LV myocyte repolarization (p<0.05) and normalized HF-induced depolarization (p<0.03) of the resting membrane potential. CRT improved HF-induced reductions in calcium (p<0.05). CRT did not attenuate the HF-induced increases in LV interstitial fibrosis. Using a translational approach in a chronic HF model, CRT significantly improved LV structure; this was accompanied by improved LV myocyte electrophysiology and calcium regulation. The beneficial effects of CRT may be attributable, in part, to improved LV myocyte function. 相似文献
183.
The genome sequence of the cyanobacterium Synechocystis sp. PCC6803 revealed four Open reading frame (ORF) encoding putative inositol monophosphatase or inositol monophosphatase-like
proteins. One of the ORFs, sll1383, is ∼870 base pair long and has been assigned as a probable myo-inositol 1 (or 4) monophosphatase (IMPase; EC 3.1.3.25). IMPase is the second enzyme in the inositol biosynthesis pathway
and catalyses the conversion of L-myo-inositol 1-phosphate to free myo-inositol. The present work describes the functional assignment of ORF sll1383 as myo-inositol 1-phosphate phosphatase (IMPase) through molecular cloning, bacterial overexpression, purification and biochemical
characterization of the gene product. Affinity (K
m) of the recombinant protein for the substrate DL-myo-inositol 1-phosphate was found to be much higher (0.0034 ± 0.0003 mM) compared to IMPase(s) from other sources but in comparison
V
max (∼0.033 μmol Pi/min/mg protein) was low. Li+ was found to be an inhibitor (IC50 6.0 mM) of this enzyme, other monovalent metal ions (e.g. Na+, K+ NH4+) having no significant effect on the enzyme activity. Like other IMPase(s), the activity of this enzyme was found to be totally
Mg2+ dependent, which can be substituted partially by Mn2+. However, unlike other IMPase(s), the enzyme is optimally active at ∼42°C. To the best of our knowledge, sll1383 encoded
IMPase has the highest substrate affinity and specificity amongst the known examples from other prokaryotic sources. A possible
application of this recombinant protein in the enzymatic coupled assay of L-myo-inositol 1-phosphate synthase (MIPS) is discussed. 相似文献
184.
185.
186.
S. Bharali R. K. Purama A. Majumder C. M. G. A. Fontes A. Goyal 《Indian journal of microbiology》2007,47(2):109-118
The non-catalytic, family 11 carbohydrate binding module (CtCBM11) belonging to a bifunctional cellulosomal cellulase from Clostridium thermocellum was hyper-expressed in E. coli and functionally characterized. Affinity electrophoresis of CtCBM11 on nondenaturing PAGE containing cellulosic polysaccharides showed binding with β-glucan, lichenan, hydroxyethyl cellulose
and carboxymethyl cellulose. In order to elucidate the involvement of conserved aromatic residues Tyr 22, Trp 65 and Tyr 129
in the polysaccharide binding, site-directed mutagenesis was carried out and the residues were changed to alanine. The results
of affinity electrophoresis and binding adsorption isotherms showed that of the three mutants Y22A, W65A and Y129A of CtCBM11, two mutants Y22A and Y129A showed no or reduced binding affinity with polysaccharides. These results showed that tyrosine
residue 22 and 129 are involved in the polysaccharide binding. These residues are present in the putative binding cleft and
play a critical role in the recognition of all the ligands recognized by the protein. 相似文献
187.
Banerjee P Morgan MT Rickus JL Ragheb K Corvalan C Robinson JP Bhunia AK 《Applied microbiology and biotechnology》2007,73(6):1423-1434
Lymphocyte origin hybridoma Ped-2E9 cell-based cytotoxicity assay can detect virulent Listeria or Bacillus species, and its application in a cell-based biosensor for onsite use would be very attractive. However, maintaining enough
viable cells on a sensor platform for a prolonged duration is a challenging task. In this study, key factors affecting the
survival and growth of Ped-2E9 cells under modified conditions were investigated. When the Ped-2E9 cells were grown in media
containing 5% fetal bovine serum in sealed tubes without any replenishment of nutrients or exogenous CO2 supply, a large portion of the cells remained viable for 6 to 7 days and cells entered into G0/G1 resting phase. The media
pH change was negligible and no cell death was observed in the first 4 days, then cells sequentially underwent apoptotic (fourth
day onward) phase until day 7 after which a majority was dead. Subsequent cytotoxicity testing of 3- to 7-day stored Ped-2E9
cells sensitively detected virulent Listeria and Bacillus species. These data strongly suggest that Ped-2E9 cells can be maintained in viable state for 6 days in a sealed tube mimicking
the environment in a potential sensor device for onsite use without the need for expensive cell culture facilities. 相似文献
188.
Determining the unknown material parameters of intact ventricular myocardium can be challenging due to highly nonlinear material behavior. Previous studies combining a gradient-search optimization procedure with finite element analysis (FEA) were limited to two-dimensional (2D) models or simplified three-dimensional (3D) geometries. Here we present a novel scheme to estimate unknown material parameters for ventricular myocardium by combining a genetic algorithm (GA) with nonlinear finite element analysis. This approach systematically explores the domain of the material parameters. The objective function to minimize was the error between simulated strain data and finite element model strains. The proposed scheme was validated for a 2D problem using a realistic material law for ventricular myocardium. Optimized material parameters were generally within 0.5% of the true values. To demonstrate the robustness of the new scheme, unknown material parameters were also determined for a realistic 3D heart model with an exponential hyperelastic material law. When using strains from two material points, the algorithm converged to parameters within 5% of the true values. We conclude that the proposed scheme is robust when estimating myocardial material parameters in 2D and 3D models. 相似文献
189.
GDI-1 phosphorylation switch at serine 96 induces RhoA activation and increased endothelial permeability
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Knezevic N Roy A Timblin B Konstantoulaki M Sharma T Malik AB Mehta D 《Molecular and cellular biology》2007,27(18):6323-6333
We identified the GDI-1-regulated mechanism of RhoA activation from the Rho-GDI-1 complex and its role in mediating increased endothelial permeability. Thrombin stimulation failed to induce RhoA activation and actin stress fiber formation in human pulmonary arterial endothelial cells transduced with full-length GDI-1. Expression of a GDI-1 mutant form (C-GDI) containing the C terminus (aa 69 to 204) also prevented RhoA activation, whereas further deletions failed to alter RhoA activation. We observed that protein kinase Calpha-mediated phosphorylation of the C terminus of GDI-1 at Ser96 reduced the affinity of GDI-1 for RhoA and thereby enabled RhoA activation. Rendering GDI-1 phosphodefective with a Ser96 --> Ala substitution rescued the inhibitory activity of GDI-1 toward RhoA but did not alter the thrombin-induced activation of other Rho GTPases, i.e., Rac1 and Cdc42. Phosphodefective mutant GDI-1 also suppressed myosin light chain phosphorylation, actin stress fiber formation, and the increased endothelial permeability induced by thrombin. In contrast, expressing the phospho-mimicking mutant S96D-GDI-1 protein induced RhoA activity and increased endothelial permeability independently of thrombin stimulation. These results demonstrate the crucial role of the phosphorylation of the C terminus of GDI-1 at S96 in selectively activating RhoA. Inhibiting GDI-1 phosphorylation at S96 is a potential therapeutic target for modulating RhoA activity and thus preventing the increase in endothelial permeability associated with vascular inflammation. 相似文献
190.
Pakhale SS Karibasappa GS Ramchandani AG Bhushan B Sharma A 《Indian journal of experimental biology》2007,45(11):968-973
Antioxidant potency of Indian grape cultivars varying in their skin color, seed and polyphenol content (Bangalore blue, Pandhari sahebi, Sharad seedless and Thompson seedless) and their components (whole grapes, pulp with skin and seeds) was examined as 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity using electron spin resonance spectrometry. The total polyphenols in Indian grapes ranged between 3-51%. Extracted polyphenols caused a concentration dependent and significant loss in DPPH radical signal, similar to known antioxidants-Vitamin C, catechin and procyanidin B3 used as references. Among seedless cultivars, polyphenols from Sharad was more potent as antioxidant than Thompson, showing IC50 values of 1250 +/- 30 and 2650 +/- 125 microg/ml, respectively. The inhibitory effect of polyphenols from seedless grape cultivars was as effective as that of seeded variety. The results indicate that polyphenols extracted from Indian grapes/ components (with /without seeds) exhibited free radical scavenging activity and their chemopreventive properties need to be exploited by in vivo model system. 相似文献