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81.
The Rhizobia are a group of free-living soil bacteria known for their ability to symbiotically infect the roots of specific host plants as well as to produce siderophores in order to compete with other microorganisms for the limited availability of iron in the rhizosphere. In this study, Rhizobium leguminosarum ATCC 14479, which preferentially infects the red clover Trifolium pratense, was found to produce the trihydroxamate siderophore vicibactin (C33H55N6O15) under iron restricted conditions. In addition, two other iron-binding, siderophore-like compounds: C20H36N4O10, C31H55N6O15, were isolated and purified from the culture media. Due to the structural similarity of the latter compounds to vicibactin based on electrospray-mass spectrometry and nuclear magnetic resonance data, these heretofore unreported molecules are thought to be either modified or degraded products of vicibactin. Although vicibactin has previously been found to be commonly produced by other rhizobial strains, this is the first time it has been chemically characterized from a clover infecting strain of R. leguminosarum. 相似文献
82.
Saritha Tantravedi Saibal Chakraborty Niti H. Shah James C. Fishbein Ramachandra S. Hosmane 《Bioorganic & medicinal chemistry》2013,21(17):4893-4903
Guanase is an important enzyme of the purine salvage pathway of nucleic acid metabolism and its inhibition has beneficial implications in viral, bacterial, and cancer therapy. The work described herein is based on a hypothesis that azepinomycin, a heterocyclic natural product and a purported transition state analog inhibitor of guanase, does not represent the true transition state of the enzyme-catalyzed reaction as closely as does iso-azepinomycin, wherein the 6-hydroxy group of azepinomycin has been translocated to the 5-position. Based on this hypothesis, and assuming that iso-azepinomycin would bind to guanase at the same active site as azepinomycin, several analogs of iso-azepinomycin were designed and successfully synthesized in order to gain a preliminary understanding of the hydrophobic and hydrophilic sites surrounding the guanase binding site of the ligand. Specifically, the analogs were designed to explore the hydrophobic pockets, if any, in the vicinity of N1, N3, and N4 nitrogen atoms as well as O5 oxygen atom of iso-azepinomycin. Biochemical inhibition studies of these analogs were performed using a mammalian guanase. Our results indicate that (1) increasing the hydrophobicity near O5 results in a negative effect, (2) translocating the hydrophobicity from N3 to N1 also results in decreased inhibition, (3) increasing the hydrophobicity near N3 or N4 produces significant enhancement of inhibition, (4) increasing the hydrophobicity at either N3 or N4 with a simultaneous increase in hydrophobicity at O5 considerably diminishes any gain in inhibition made by solely enhancing hydrophobicity at N3 or N4, and (5) finally, increasing the hydrophilic character near N3 has also a deleterious effect on inhibition. The most potent compound in the series has a Ki value of 8.0 ± 1.5 μM against rabbit liver guanase. 相似文献
83.
Renu Deswal Ravi Gupta Vivek Dogra Raksha Singh Jasmeet Kaur Abat Abhijit Sarkar Yogesh Mishra Vandana Rai Yelam Sreenivasulu Ramesh Sundar Amalraj Manish Raorane Ram Prasad Chaudhary Ajay Kohli Ashok Prabhakar Giri Niranjan Chakraborty Sajad Majeed Zargar Vishwanath Prasad Agrawal Ganesh Kumar Agrawal Dominique Job Jenny Renaut Randeep Rakwal 《Physiology and Molecular Biology of Plants》2013,19(4):461-477
Plant proteomics has made tremendous contributions in understanding the complex processes of plant biology. Here, its current status in India and Nepal is discussed. Gel-based proteomics is predominantly utilized on crops and non-crops to analyze majorly abiotic (49 %) and biotic (18 %) stress, development (11 %) and post-translational modifications (7 %). Rice is the most explored system (36 %) with major focus on abiotic mainly dehydration (36 %) stress. In spite of expensive proteomics setup and scarcity of trained workforce, output in form of publications is encouraging. To boost plant proteomics in India and Nepal, researchers have discussed ground level issues among themselves and with the International Plant Proteomics Organization (INPPO) to act in priority on concerns like food security. Active collaboration may help in translating this knowledge to fruitful applications. 相似文献
84.
Mehjabeen Hossain Dil Umme Salma Chowdhury Jacy Farhana Mohammed Touaha Akbar Ananya Chakraborty Shamima Islam Adnan Mannan 《Bioinformation》2013,9(4):187-192
Staphylococcus aureus is a gram positive bacterium, responsible for both community-acquired and hospital-acquired infection,
resulting in a mortality rate of 39%. 43.2% resistance to methicilin and emerging resistance to Fluroquinolone and Oxazolidinone,
have evoked the necessity of the establishment of alternative and effective therapeutic approach to treat this bacteria. In this
computational study, various database and online software are used to determine some specific targets of Staphylococcus aureus
N315 other than those used by Penicillin, Quinolone and Oxazolidinone. For this purpose, among 302 essential proteins, 101 nonhomologous
proteins were accrued and 64 proteins which are unique in several metabolic pathways of S. aureus were isolated by
using metabolic pathway analysis tools. Furthermore, 7 essentially unique enzymes involved in exclusive metabolic pathways were
revealed by this research, which can be potential drug target. Along with these important enzymes, 15 non-homologous proteins
located on membrane were identified, which can play a vital role as potential therapeutic targets for the future researchers. 相似文献
85.
Anirban Chakraborty Flynn Picardal 《World journal of microbiology & biotechnology》2013,29(4):617-623
A species of Dechloromonas, strain UWNR4, was isolated from a nitrate-reducing, enrichment culture obtained from Wisconsin River (USA) sediments. This strain was characterized for anaerobic oxidation of both aqueous and chelated Fe(II) coupled to nitrate reduction at circumneutral pH. Dechloromonas sp. UWNR4 was incubated in anoxic batch reactors in a defined medium containing 4.5–5 mM NO3 ?, 6 mM Fe2+ and 1–1.8 mM acetate. Strain UWNR4 efficiently oxidized Fe2+ with 90 % oxidation of Fe2+ after 3 days of incubation. However, oxidation of Fe2+ resulted in Fe(III)-hydroxide-encrusted cells and loss of metabolic activity, suggested by inability of the cells to utilize further additions of acetate. In similar experiments with chelated iron (Fe(II)-EDTA), encrusted cells were not produced and further additions of acetate and Fe(II)-EDTA could be oxidized. Although members of the genus Dechloromonas are primarily known as perchlorate and nitrate reducers, our findings suggest that some species could be members of microbial communities influencing iron redox cycling in anoxic, freshwater sediments. Our work using Fe(II)-EDTA also demonstrates that Fe(II) oxidation was microbially catalyzed rather than a result of abiotic oxidation by biogenic NO2 ?. 相似文献
86.
87.
Lily L. Wong Suzanne M. Hirst Quentin N. Pye Christopher M. Reilly Sudipta Seal James F. McGinnis 《PloS one》2013,8(3)
Cerium oxide nanoparticles (nanoceria) possess catalytic and regenerative radical scavenging activities. The ability of nanoceria to maintain cellular redox balance makes them ideal candidates for treatment of retinal diseases whose development is tightly associated with oxidative damage. We have demonstrated that our stable water-dispersed nanoceria delay photoreceptor cell degeneration in rodent models and prevent pathological retinal neovascularization in vldlr mutant mice. The objectives of the current study were to determine the temporal and spatial distributions of nanoceria after a single intravitreal injection, and to determine if nanoceria had any toxic effects in healthy rat retinas. Using inductively-coupled plasma mass spectrometry (ICP-MS), we discovered that nanoceria were rapidly taken up by the retina and were preferentially retained in this tissue even after 120 days. We also did not observe any acute or long-term negative effects of nanoceria on retinal function or cytoarchitecture even after this long-term exposure. Because nanoceria are effective at low dosages, nontoxic and are retained in the retina for extended periods, we conclude that nanoceria are promising ophthalmic therapeutics for treating retinal diseases known to involve oxidative stress in their pathogeneses. 相似文献
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