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排序方式: 共有146条查询结果,搜索用时 15 毫秒
1.
本研究工作中,建立了一个有效的甜菜坏死黄脉病毒的分离提纯程序,解决了该病毒粒体易于聚集难以提纯的问题,其操作要点是,(1)通过Sepharose 2B柱层析代替超离心,有效地除去一些小分子量核酸杂质;(2)经PEG再次沉淀浓缩后,调整pH至酸牲(pH3.0),使病毒充分悬浮以减少凝聚;(3)在病毒等电点(pH4.8~4.9)条件下,进一步沉淀以纯化病毒。根据病毒提取物的OD260/OD280比值,算出核酸含量约4.5%。核酸电泳出现4条带,分子量分别为:2.25×10~(?),1.8×10~(?),1.05×10~(?),0.75×10~(?)道尔顿。病毒提取物经超速离心出现4个界面,沉淀系数分别为,200.8S,165S,125.8S,100S。说明甜菜坏死黄脉病毒可能是4组分病毒粒体。病毒粒体含一蛋白亚基,分子量约为2.05±0.05×10~4道尔顿,由16种共199个氨基酸组成。 相似文献
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Amit Kumar Solanki Abhishek Acharya Himani Kaushik Bharti Bhatia Lalit C Garg 《Bioinformation》2021,17(6):628
Beta toxin from Clostridium perfringens after being secreted in gut is capable of causing necrotic enteritis in humans and several other animal species and does not respond to routinely used antibiotics. Therefore, there is a need to design an effective inhibitor for the Clostridium perfringens beta toxin (CPB) using cutting edge drug discovery technologies. Hence, potential CPB inhibitors were identified using computer aided screening of compounds from the ZINC database. Further, we document the molecular docking analysis of Clostridium perfringens beta toxin model (that revealed 4 binding pockets, A-D) with the identified potential inhibitors. We show that ZINC291192 [N-[(1-methylindol-3-yl) methyl eneamino]-7,10-dioxabicyclo[4.4.0]deca-2,4,11-triene-8- carboxamide] has optimal binding features with calculated binding energy of -10.38 kcal/mol and inhibition constant of 24.76 nM for further consideration. 相似文献
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Jahovic N Sener G Cevik H Ersoy Y Arbak S Yeğen BC 《Cell biochemistry and function》2004,22(3):169-178
The anti-tumour drug methotrexate (MTX) induces intestinal mucosa injury resulting in malabsorption and diarrhoea. The purpose of this study was to investigate whether exogenous melatonin could protect the gut from MTX-induced damage in rats. A single dose of MTX (20 mg kg(-1), i.p.) was followed by i.p. saline or melatonin injections (10 mg kg(-1), MTX + Mel) for the next 5 days. On the fifth day, intestinal transit was assessed using charcoal propagation. Rats were decapitated and small intestinal segments were fixed for light (LM) and scanning electron microscope (SEM) examinations. Other intestinal segments were stored to measure glutathione (GSH) and malondialdehyde (MDA) levels, myeloperoxidase (MPO) and ATPase activity. MTX led to loss of more than 10% of the initial body weight (p < 0.01). Conversely, weight loss was markedly less in the melatonin-treated MTX group (p < 0.05). Bowel motility was increased in MTX-treated rats, while the transit index in the MTX-Mel group was not different from the control group. MTX caused decreases in GSH levels and ATPase activity, with increases in MDA levels and MPO activity. These changes were reversed in MTX-Mel-treated rats (p < 0.05-p < 0.001). LM and SEM in the MTX group revealed desquamation of surface epithelium and glandular degeneration, while the epithelium was slightly damaged in the MTX-Mel group. In conclusion, the present study demonstrates that melatonin is capable of reversing MTX-induced intestinal dysfunctions, indicating that it may be beneficial in ameliorating the symptoms of chemotherapy-induced enteritis. 相似文献
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Down-regulation of antioxidative capacity in a transgenic tobacco which fails to develop acquired resistance to necrotization caused by TMV 总被引:5,自引:0,他引:5
Antioxidant status was assayed in leaves of two local lesion hosts of tobacco mosaic virus (TMV), namely in wild-type Xanthi-nc tobacco and in NahG transgenic tobacco, the latter of which is not able to accumulate salicylic acid (SA) and therefore is unable to develop systemic acquired resistance (SAR). Activities of several enzymes related to antioxidative defense, and the levels of glutathione, chlorogenic acid and rutin were studied. The majority of antioxidant enzymes were less active in uninfected NahG tobacco than in Xanthi-nc. Furthermore, important enzymatic and non-enzymatic antioxidants were down-regulated in TMV-infected NahG plants, as compared to Xanthi-nc. Correspondingly, SA pretreatment primed the leaves for stronger induction of antioxidants in infected Xanthi-nc, but not in NahG tobaccos. The antioxidant status of NahG tobacco even decreased after an attempted induction of SAR, while the antioxidative level increased in Xanthi-nc leaves in which the SAR was successfully induced. After infection, a greater accumulation of superoxide and H 2 O 2 , and a more intensive necrotization was positively correlated with the reduced capability of NahG leaf tissue to detoxify reactive oxygen species. 相似文献
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Poultry necrotic enteritis (NE) is caused by specific strains of Clostridium perfringens, most of which are type A. The role of alpha toxin (CPA) in NE has been called into question by the finding that an engineered cpa mutant retains full virulence in vivo[9]. This is in contrast to the finding that immunization with CPA toxoids protects against NE. We confirmed the earlier findings, in that 14-day-old Cornish × Rock broiler chicks challenged with a cpa mutant developed lesions compatible with NE in >90% of birds inoculated with the mutant. However, CPA was detected in amounts ranging from 10 to >100 ng per g of gut contents and mucosa in birds inoculated with the cpa mutant, the wildtype strain from which the mutant was constructed, and our positive control strain. There was a direct relationship between lesion severity and amount of CPA detected (R = 0.89-0.99). These findings suggest that the role of CPA in pathogenesis of NE requires further investigation. 相似文献
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Simulating complex tumor dynamics from avascular to vascular growth using a general level-set method
A comprehensive continuum model of solid tumor evolution and development is investigated in detail numerically, both under
the assumption of spherical symmetry and for arbitrary two-dimensional growth. The level set approach is used to obtain solutions
for a recently developed multi-cell transport model formulated as a moving boundary problem for the evolution of the tumor.
The model represents both the avascular and the vascular phase of growth, and is able to simulate when the transition occurs;
progressive formation of a necrotic core and a rim structure in the tumor during the avascular phase are also captured. In
terms of transport processes, the interaction of the tumor with the surrounding tissue is realistically incorporated. The
two-dimensional simulation results are presented for different initial configurations. The computational framework, based
on a Cartesian mesh/narrow band level-set method, can be applied to similar models that require the solution of coupled advection-diffusion
equations with a moving boundary inside a fixed domain. The solution algorithm is designed so that extension to three-dimensional
simulations is straightforward. 相似文献