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排序方式: 共有439条查询结果,搜索用时 15 毫秒
41.
T. S. Suryanarayanan T. S. Murali N. Thirunavukkarasu M. B. Govinda Rajulu G. Venkatesan R. Sukumar 《Biodiversity and Conservation》2011,20(5):913-928
Fungal endophytes of tropical trees are expected to be exceptionally species rich as a consequence of high tree diversity
in the tropics and the purported host restriction among the endophytes. Based on this premise, endophytes have been regarded
as a focal group for estimating fungal numbers because their possible hyperdiverse nature would reflect significantly global
fungal diversity. We present our consolidated ten-year work on 75 dicotyledonous tree hosts belonging to 33 families and growing
in three different types of tropical forests of the NBR in the Western Ghats, southern India. We conclude that endophyte diversity
in these forests is limited due to loose host affiliations among endophytes. Some endophytes have a wide host range and colonize
taxonomically disparate hosts suggesting adaptations in them to counter a variety of defense chemicals in their hosts. Furthermore,
such polyphagous endophytes dominate the endophyte assemblages of different tree hosts. Individual leaves may be densely colonized
but only by a few endophyte species. It appears that the environment (the type of forest in this case) has a larger role in
determining the endophyte assemblage of a plant host than the taxonomy of the host plant. Thus, different tropical plant communities
have to be studied for their endophyte diversity to test the generalization that endophytes are hyperdiverse in the tropics,
estimate their true species richness, and use them as a predictor group for more accurate assessment of global fungal diversity. 相似文献
42.
Koch Rainer Lipton Andrew S. Filipek Slawomir Renugopalakrishnan Venkatesan 《Journal of molecular modeling》2011,17(6):1467-1472
Density functional theoretical calculations have been utilized to investigate the interaction of the amino acid arginine with
the (100) surface of anatase and the reproduction of experimentally measured 49Ti NMR chemical shifts of anatase. Significant binding of arginine through electrostatic interaction and hydrogen bonds of
the arginine guanidinium protons to the TiO2 surface oxygen atoms is observed, allowing attachment of proteins to titania surfaces in the construction of bio-sensitized
solar cells. GIAO-B3LYP/6-31G(d) NMR calculation of a three-layer model based on the experimental structure of this TiO2 modification gives an excellent reproduction of the experimental value (-927 ppm) within +/- 7 ppm, however, the change in
relative chemical shifts, EFGs and CSA suggest that the effect of the electrostatic arginine binding might be too small for
experimental detection. 相似文献
43.
Kanmani P Kumar RS Yuvaraj N Paari KA Pattukumar V Arul V 《Preparative biochemistry & biotechnology》2011,41(1):40-52
Statistics-based experimental designs were used to develop a cost-effective medium for enhanced production of viable cells and bacteriocin by probiotic Enterococcus faecium MC13. Carbon, nitrogen, and mineral sources were first screened by one-variable-at-a-time (OVAT) methods. In order to increase yield production, the selected variables were further statistically optimized using response-surface methodology (RSM) with central composite design (CCD). The maximum and minimum levels of the selected variables were determined and a set of 34 experimental runs was performed. The optimum concentrations of the tested variables for production of viable cells (12.24 log CFU mL(-1)) and bacteriocin activity (25,600 AU mL(-1)) were tryptone (10.0 g/L), peptone (6.0 g/L), maltose (3.0 g/L), glucose (9.0 g/L), NaCl (15.0 g/L), sodium citrate (2.5 g/L), sodium acetate (1.0 g/L), and dipotassium PO(4) (0.1 g/L). Threefold increased yield of bacteriocin was achieved in optimized medium compared to the unoptimized counterpart, and this was two times less cost than commercial MRS medium. 相似文献
44.
Vijayabharathi R Bruheim P Andreassen T Raja DS Devi PB Sathyabama S Priyadarisini VB 《Journal of microbiology (Seoul, Korea)》2011,49(6):920-926
A new actinomycete strain, isolated from humus soils in the Western Ghats, was found to be an efficient pigment producer.
The strain, designated AAA5, was identified as a putative Streptomyces aurantiacus strain based on cultural properties, morphology, carbon source utilization, and analysis of the 16S rRNA gene. The strain
produced a reddish-brown pigmented compound during the secondary metabolites phase. A yellow compound was derived from the
extracted pigment and was identified as the quinone-related antibiotic resistomycin based on ultraviolet-visible spectrophotometry,
fourier transform infrared spectroscopy, liquid chromatography and mass spectroscopy, and nuclear magnetic resonance analyses.
The AAA5 strain was found to produce large quantities of resistomycin (52.5 mg/L). It showed potent cytotoxic activity against
cell lines viz. HepG2 (hepatic carcinoma) and HeLa (cervical carcinoma) in vitro, with growth inhibition (GI50) of 0.006 and 0.005 μg/ml, respectively. The strain also exhibited broad antimicrobial activities against both Gram-positive
and Gram-negative bacteria. Therefore, AAA5 may have great potential as an industrial resistomycin-producing strain. 相似文献
45.
46.
Thachamvally Riyesh Vinayagamurthy Balamurugan Arnab Sen Veerakyathappa Bhanuprakash Gnanavel Venkatesan Vinita Yadav Raj Kumar Singh 《中国病毒学》2011,26(5):324-337
In this study, thermo-adapted (Ta) PPR vaccines were assessed for their stability at 25, 37, 40, 42 and 45°C in lyophilized
form using two extrinsic stabilizers {lactalbumin hydrolysate-sucrose (LS) and stabilizer E} and in reconstituted form with
the diluents (1 mol/L MgSO4 or 0.85% NaCl). The lyophilized vaccines showed an expiry period of 24–26 days at 25°C, 7–8 days at 37°C and 3–4 days at
40°C. LS stabilizer was superior at 42°C with a shelf-life of 44 h, whereas in stabilizer E, a 40 h shelf-life with a comparable
half-life was observed. At 45°C, the half-life in stabilizer E was better than LS and lasted for 1 day. Furthermore, the reconstituted
vaccine maintained the titre for 48 h both at 4°C and 25°C and for 24–30 h at 37°C. As both the stabilizers performed equally
well with regard to shelf-life and half-life, the present study suggests LS as stabilizer as a choice for lyophilization with
0.85% NaCl diluent, because it has better performance at higher temperature. These Ta vaccines can be used as alternatives
to existing vaccines for the control of the disease in tropical countries as they are effective in avoiding vaccination failure
due to the breakdown in cold-chain maintenance, as this vaccine is considerably more stable at ambient temperatures. 相似文献
47.
48.
Rose JJ Janvier K Chandrasekhar S Sekaly RP Bonifacino JS Venkatesan S 《The Journal of biological chemistry》2005,280(9):7413-7426
Among the pleiotropic effects of Nef proteins of HIV and simian immunodeficiency virus (SIV), down-modulation of cell surface expression of CD4 is a prominent phenotype. It has been presumed that Nef proteins accelerate endocytosis of CD4 by linking the receptor to the AP-2 clathrin adaptor. However, the related AP-1 and AP-3 adaptors have also been shown to interact with Nef, hinting at role(s) for these complexes in the intracellular retention of CD4. By using genetic inhibitors of endocytosis and small interfering RNA-induced knockdown of AP-2, we show that accelerated CD4 endocytosis is not a dominant mechanism of HIV-1 (NL4-3 strain) Nef in epithelial cells, T lymphocyte cell lines, or peripheral blood lymphocytes. Furthermore, we show that both the CD4 recycling from the plasma membrane and the nascent CD4 in transit to the plasma membrane are susceptible to intracellular retention in HIV-1 Nef-expressing cells. In contrast, AP-2-mediated enhanced endocytosis constitutes the predominant mechanism for SIV (MAC-239 strain) Nef-induced down-regulation of human CD4 in human cells. 相似文献
49.
Venkatesan Ramakrishnan Xavier Alexander Marialouis Jagadesan Sankarasubramanian Amutha Santhanam Anand Setty Balakrishnan 《Bioinformation》2021,17(1):126
The emerging NDM-producing Enterobactereciae is a major threat to public health. The association of NDM-7 with sequence type 101 E.coli is identified in very few numbers. Therefore, it is of interest to analyse the whole genome sequence of NDM-producing uropathogenic E. coli XA31 that was found to carry numerous drug resistance genes of different antibiotic classes. The isolate E. coli belongs to ST-101 carrying blaNDM-7 coexisting with several resistance genes blaOXA-1, blaTEM1-A, blaCTX-M15, aac(6'')-Ib-cr, catB3, tetB. Resfinder predicts this and four other plasmid replicons were identified using the Plasfinder in the CGE platform. The high transferable IncX3 plasmid was found to carry the NDM-7 gene. Thus, we the report the combination of NDM-7-ST101-IncX3 in India. The combination of this epidemic clone with NDM-7 is highly required to develop an effective infection control strategy. 相似文献
50.
Muthukumar Karuppasamy Manojkumar Mahapatra Samiye Yabanoglu Gulberk Ucar Barij Nayan Sinha Arijit Basu Nibha Mishra Ashoke Sharon Umasankar Kulandaivelu Venkatesan Jayaprakash 《Bioorganic & medicinal chemistry》2010,18(5):1875-1881
3,5-Diaryl pyrazolines analogs were synthesized and evaluated for their monoamine oxidase (MAO) inhibitory activity. The compounds were found reversible and selective towards MAO-A with selectivity index in the magnitude of 103–105. The docking studies were carried out to gain further structural insights of the binding mode and possible interactions with the active site of MAO-A. Interestingly, the theoretical (Ki) values obtained by molecular docking studies were in congruence with their experimental (Ki) values. 相似文献