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51.
Vijay M. Khedkar Premlata K. Ambre Jitender Verma Mushtaque S. Shaikh Raghuvir R. S. Pissurlenkar Evans C. Coutinho 《Journal of molecular modeling》2010,16(7):1251-1268
HIV-1 protease is an obligatory enzyme in the replication process of the HIV virus. The abundance of structural information
on HIV-1PR has made the enzyme an attractive target for computer-aided drug design strategies. The daunting ability of the
virus to rapidly generate resistant mutants suggests that there is an ongoing need for new HIV-1PR inhibitors with better
efficacy profiles and reduced toxicity. In the present investigation, molecular modeling studies were performed on a series
of 54 cyclic urea analogs with symmetric P2/P2′ substituents. The binding modes of these inhibitors were determined by docking.
The docking results also provided a reliable conformational superimposition scheme for the 3D-QSAR studies. To gain insight
into the steric, electrostatic, hydrophobic and hydrogen-bonding properties of these molecules and their influence on the
inhibitory activity, comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA)
were performed. Two different alignment schemes viz. receptor-based and atom-fit alignment, were used in this study to build the QSAR models. The derived 3D-QSAR models were found to be robust with statistically
significant r
2
and r
2
pred
values and have led to the identification of regions important for steric, hydrophobic and electronic interactions. The predictive
ability of the models was assessed on a set of molecules that were not included in the training set. Superimposition of the
3D-contour maps generated from these models onto the active site of enzyme provided additional insight into the structural
requirements of these inhibitors. The CoMFA and CoMSIA models were used to design some new inhibitors with improved binding
affinity. Pharmacokinetic and toxicity predictions were also carried out for these molecules to gauge their ADME and safety
profile. The computational results may open up new avenues for synthesis of potent HIV-1 protease inhibitors. 相似文献
52.
Xiaozhou Du Matthew Zeglinski Nasir Shaikh Davinder S Jassal 《Cardiovascular ultrasound》2010,8(1):1-2
Various structural anomalies of the left ventricular papillary muscles have been observed in recent years. Many of these have been linked to electrocardiographic aberrations. Recently two reports have appeared where the base of the posterior papillary muscle was identified as the source of frequent premature ventricular complexes. In some of these patients these frequent premature ventricular complexes have led to left ventricular dysfunction. In this report a newly discovered structural variant of the anterior papillary muscle is described--the bifid papillary muscle. Furthermore, it is proposed that this bifid papillary muscle is the source of frequent ventricular premature complexes, presenting as bigeminy in a patient with normal left ventricular function. 相似文献
53.
Besser TE Shaikh N Holt NJ Tarr PI Konkel ME Malik-Kale P Walsh CW Whittam TS Bono JL 《Applied and environmental microbiology》2007,73(3):671-679
Escherichia coli O157:H7, a zoonotic human pathogen for which domestic cattle are a reservoir host, produces a Shiga toxin(s) (Stx) encoded by bacteriophages. Chromosomal insertion sites of these bacteriophages define three principal genotypes (clusters 1 to 3) among clinical isolates of E. coli O157:H7. Stx-encoding bacteriophage insertion site genotypes of 282 clinical and 80 bovine isolates were evaluated. A total of 268 (95.0%) of the clinical isolates, but only 41 (51.3%) of the bovine isolates, belonged to cluster 1, 2, or 3 (P < 0.001). Thirteen additional genotypes were identified in isolates from both cattle and humans (four genotypes), from only cattle (seven genotypes), or from only humans (two genotypes). Two other markers previously associated with isolates from cattle or with clinical isolates showed similar associations with genotype groups within bovine isolates; the tir allele sp-1 and the Q933W allele were under- and overrepresented, respectively, among cluster 1 to 3 genotypes. Stx-encoding bacteriophage insertion site typing demonstrated that there is broad genetic diversity of E. coli O157:H7 in the bovine reservoir and that numerous genotypes are significantly underrepresented among clinical isolates, consistent with the possibility that there is reduced virulence or transmissibility to humans of some bovine E. coli O157:H7 genotypes. 相似文献
54.
Oligonucleotides containing 7-deaza-2'-deoxyxanthosine (1) and 2'-deoxyxanthosine (2) were prepared. The 2-(4-nitrophenyl)ethyl group is applicable for 7-deazaxanthine protection that is removed with DBU by beta-elimination, while the deprotection of the allyl residue with Pd (0) catalyst failed. Contrarily, the allyl group was found to be an excellent protecting group for 2'-deoxyxanthosine (2). The base pairing of nucleosides 1 and 2 with the four canonical DNA constituents as well as with 3 within the 12-mer duplexes is studied. 相似文献
55.
Yasar Nishat Mohammad Danish Heba I. Mohamed Hisamuddin Shaikh Abeer Elhakem 《Phyton》2022,91(8):1757-1777
Meloidogyne incognita is a plant pathogen causing root-knot disease and loss of crop yield. The present study
aimed to use Trichoderma harzianum as a biocontrol agent against plant-parasitic nematodes and used press
mud, which is a solid waste by-product of sugarcane, as a biocontrol agent and biofertilizer. Therefore, the combined application of T. harzianum and press mud may enhance nematode control and plant growth. Elemental
analysis of press mud using scanning electron microscopy (SEM) integrated with an Energy Dispersive X-ray
(EDX) analyzer revealed the presence of different elements such as C, O, Mg, Si, P, K, Ca, Cu and Zn. In addition,
a greenhouse study was conducted to investigate the combined effects of press mud and T. harzianum on M.
incognita reproduction and growth and the biochemical features of Psoralea corylifolia. The results showed that
plant length, dry biomass, leaf area, the number of seeds per plant, chlorophyll a, chl b, carotenoid content, nitrate
reductase, carbonic anhydrase, and nitrogen content were significantly increased (P ≤ 0.05) in the T2 plants
(plants were treated with 100 g of press mud + 50 mL T. harzianum before one week of M. incognita inoculation),
over inoculated plants (IC). Antioxidant enzyme activity of ascorbate peroxidase (APX), catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) in the foliage of P. corylifolia was significantly increased when
plants were treated with press mud + T. harzianum. A significant reduction in the number of egg masses, nematode population, and root-knot index (RKI) was found in plants with T2 plants. These results suggest that the
combined application of T. harzianum and press mud has the potential to control the M. incognita infection
and can be used as an environmentally safe alternative to chemical nematicides and also help in the removal
of sugarcane waste that causes environmental pollution. 相似文献
56.
Molecular architecture of the ribosome‐bound Hepatitis C Virus internal ribosomal entry site RNA
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Justus Loerke Jochen Ismer Andrea Schmidt Tarek Hilal Thiemo Sprink Kaori Yamamoto Thorsten Mielke Jörg Bürger Tanvir R Shaikh Marylena Dabrowski Peter W Hildebrand Patrick Scheerer Christian MT Spahn 《The EMBO journal》2015,34(24):3042-3058
Internal ribosomal entry sites (IRESs) are structured cis‐acting RNAs that drive an alternative, cap‐independent translation initiation pathway. They are used by many viruses to hijack the translational machinery of the host cell. IRESs facilitate translation initiation by recruiting and actively manipulating the eukaryotic ribosome using only a subset of canonical initiation factor and IRES transacting factors. Here we present cryo‐EM reconstructions of the ribosome 80S‐ and 40S‐bound Hepatitis C Virus (HCV) IRES. The presence of four subpopulations for the 80S•HCV IRES complex reveals dynamic conformational modes of the complex. At a global resolution of 3.9 Å for the most stable complex, a derived atomic model reveals a complex fold of the IRES RNA and molecular details of its interaction with the ribosome. The comparison of obtained structures explains how a modular architecture facilitates mRNA loading and tRNA binding to the P‐site. This information provides the structural foundation for understanding the mechanism of HCV IRES RNA‐driven translation initiation. 相似文献
57.
58.
Effect of Pre‐ and Post–Combined Multidoses of Epigallocatechin Gallate and Coenzyme Q10 on Cisplatin‐Induced Oxidative Stress in Rat Kidney
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Sabiha Fatima Noura Al‐Mohaimeed Sadia Arjumand Naheed Banu Noura Al‐Jameil Yazeed Al‐Shaikh 《Journal of biochemical and molecular toxicology》2015,29(2):91-97
The nephroprotective effect of coenzyme Q10 and epigallocatechin gallate was investigated in rats with acute renal injury induced by a single nephrotoxic dose of cisplatin. Two days prior to cisplatin administration, epigallocatechin gallate and coenzyme Q10 alone and in four different combinations were given for 6 days. The treatment with antioxidants significantly protected the cisplatin‐induced increase in the levels of blood urea nitrogen and serum creatinine. Both the antioxidants alone or in different combinations significantly compensated the increased malondialdehyde and reduced glutathione levels. Moreover, the decrease in the activities of superoxide dismutase, catalase, and glutathione peroxidase and the concentration of selenium, zinc, and copper ions were significantly attenuated in renal tissue. In conclusion, epigallocatechin gallate and coenzyme Q10 are equally effective against cisplatin‐induced nephrotoxicity, whereas the intervention by combining these two antioxidants was found to be highly effective at low doses in attenuating oxidative stress in rat kidney. 相似文献
59.
Sibhghatulla Shaikh Jamale Fatima Shazi Shakil Syed Mohd. Danish Rizvi Mohammad Amjad Kamal 《Saudi Journal of Biological Sciences》2015,22(1):62-64
Resistance to broad-spectrum beta-lactams, mediated by extended-spectrum beta-lactamase enzymes (ESBL), is an increasing problem worldwide. The present study was undertaken to determine the incidence of ESBL-production among the clinical isolates of Pseudomonas aeruginosa and their susceptibility to selected antimicrobials. A total of one eighty-seven clinical specimens were tested for the presence of ESBL production using the double-disc synergy test. Of these, 25.13% (n = 47) isolates of P. aeruginosa were observed as ESBL positive. The maximum number of ESBL-producing strains were found in sputum (41.67%; n = 24) followed by pus (28.36%; n = 19), cerebrospinal fluid and other body fluids (21.74%; n = 5), urine (20.45%; n = 9) and blood (13.79%; n = 4). ESBL producing isolates exhibited co-resistance to an array of antibiotics tested. Imipenem and meropenem can be suggested as the drugs of choice in our study. 相似文献
60.
Zabet-Moghaddam M Shaikh AL Jones LB Niwayama S 《Bioorganic & medicinal chemistry letters》2011,21(15):4629-4632
Benzoyloxysuccinimide and its d5-labeled version, which react with amino groups in the N-termini and lysine side chains in proteins, were synthesized and applied to quantitative analysis of peptides and a commercially available protein in combination with a MALDI mass spectrometer. 相似文献