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排序方式: 共有457条查询结果,搜索用时 10 毫秒
1.
Sudhanshu Vrati 《Applied microbiology and biotechnology》1984,19(3):199-202
Summary Anaerobically digested cow dung was separated by centrifugation into solid residue and liquid supernatant fractions. Clarified supernatant fraction, rich in volatile fatty acids, supported the growth of photosynthetic bacteria. Single cell protein from different photosynthetic bacteria, grown on clarified supernatant, was found to be rich in essential and sulphur amino acids. Rhodopseudomonas capsulata produced the best single cell protein. 相似文献
2.
Glutamine synthetase I fromRhizobium meliloti was found to be inhibited by adenosine 5-monophosphate, alanine, glycine, carbamyl phosphate, cytidine 5-triphosphate, tryptophan, histidine, and glucosamine-6-phosphate. Each inhibitor was independent in its action and the effect was cumulative when more than one inhibitor was added. 相似文献
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4.
Appaiahgari MB Saini M Rauthan M Jyoti Vrati S 《Microbes and infection / Institut Pasteur》2006,8(1):92-104
Replication-defective recombinant adenoviruses (RAds) were constructed that synthesized the pre-membrane and envelope (E) proteins of Japanese encephalitis virus (JEV). Recombinant virus RAdEa synthesized Ea, the membrane-anchored E protein, and RAdEs synthesized Es, the secretory E protein. Compared with RAdEs, RAdEa replicated poorly in HEK 293A cells and synthesized lower amounts of E protein. Oral immunization of mice with RAds generated low titers of anti-JEV antibodies that had little JEV neutralizing activity. Intra-muscular (IM) immunization of mice with either RAd generated high titers of anti-JEV antibodies. Interestingly, RAdEa induced only low titers of JEV neutralizing antibodies. Titers were significantly higher in case of RAdEs immunization. Splenocytes from mice immunized IM with RAds secreted large amounts of interferon-γ and moderate amounts of interleukin-5 in the presence of JEV and showed cytotoxic activity against JEV-infected cells. Naïve mice immunized IM with RAdEs showed complete protection against a lethal dose of JEV given intra-cerebrally. In order to study the effect of the pre-existing adenovirus 5 (Ad5) immunity on the outcome of the RAdEs immunization, mice were exposed to Ad5 through IM or intra-nasal (IN) routes before immunization with RAdEs. Mice exposed to Ad5 through the IN route, when immunized with RAdEs given IM, or those exposed to Ad5 through the IM route, when immunized with RAdEs given IN, were completely protected against lethal JEV challenge. 相似文献
5.
Four different bacterial isolates obtained from a stable bacterial consortium were capable of utilizing pentachlorophenol
(PCP) as sole carbon and energy source. The consortium was developed by continuous enrichment in the chemostat. The degradation
of PCP by bacterial strain was preceded through an oxidative route as indicated by accumulation of tetrachloro-ρ-hydroquinone
and dichlorohydroquinone as determined by high performance liquid chromatography (HPLC). Among the four isolates, Pseudomonas fluorescens exhibited maximum degradation capability and enzyme production. PCP-monooxygenase enzyme was extracted from culture extract
and fractionated by DEAE-cellulose ion exchange chromatography. The molecular weight of the enzyme, purified from Pseudomonas fluorescens, determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and gel filtration chromatography was
found to be 24,000 Da.
Received: 22 July 2002 / Accepted: 23 September 2002 相似文献
6.
Chiu-Hao Chen Sai Venkatesh Pingali Shekhar Garde Mark L. Schlossman 《Biophysical journal》2009,97(10):2794-2802
X-ray reflectivity measurements are used to determine the configuration of the C2 domain of protein kinase Cα (PKCα-C2) bound to a lipid monolayer of a 7:3 mixture of 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine and 1-stearoyl-2-oleoyl-sn-glycero-3-phosphoserine supported on a buffered aqueous solution. The reflectivity is analyzed in terms of the known crystallographic structure of PKCα-C2 and a slab model representation of the lipid layer. The configuration of lipid-bound PKCα-C2 is described by two angles that define its orientation, θ = 35° ± 10° and φ =210° ± 30°, and a penetration depth (=7.5 ± 2 Å) into the lipid layer. In this structure, the β-sheets of PKCα-C2 are nearly perpendicular to the lipid layer and the domain penetrates into the headgroup region of the lipid layer, but not into the tailgroup region. This configuration of PKCα-C2 determined by our x-ray reflectivity is consistent with many previous findings, particularly mutational studies, and also provides what we believe is new molecular insight into the mechanism of PKCα enzyme activation. Our analysis method, which allows us to test all possible protein orientations, shows that our data cannot be explained by a protein that is orientated parallel to the membrane, as suggested by earlier work. 相似文献
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8.
Masashi Kato Mayuko Y. Kumasaka Shoko Ohnuma Akio Furuta Yoko Kato Hossain U. Shekhar Michiyo Kojima Yasuko Koike Nguyen Dinh Thang Nobutaka Ohgami Thuy Bich Ly Xiaofang Jia Husna Yetti Hisao Naito Gaku Ichihara Ichiro Yajima 《PloS one》2013,8(6)
Health risk for well drinking water is a worldwide problem. Our recent studies showed increased toxicity by exposure to barium alone (≤700 µg/L) and coexposure to barium (137 µg/L) and arsenic (225 µg/L). The present edition of WHO health-based guidelines for drinking water revised in 2011 has maintained the values of arsenic (10 µg/L) and barium (700 µg/L), but not elements such as manganese, iron and zinc. Nevertheless, there have been very few studies on barium in drinking water and human samples. This study showed significant correlations between levels of arsenic and barium, but not its homologous elements (magnesium, calcium and strontium), in urine, toenail and hair samples obtained from residents of Jessore, Bangladesh. Significant correlation between levels of arsenic and barium in well drinking water and levels in human urine, toenail and hair samples were also observed. Based on these results, a high-performance and low-cost adsorbent composed of a hydrotalcite-like compound for barium and arsenic was developed. The adsorbent reduced levels of barium and arsenic from well water in Bangladesh and Vietnam to <7 µg/L within 1 min. Thus, we have showed levels of arsenic and barium in humans and propose a novel remediation system. 相似文献
9.
Winter varieties of plants can flower only after exposure to prolonged cold. This phenomenon is known as vernalization and has been widely studied in the model plant Arabidopsis thaliana as well as in monocots. Through the repression of floral activator genes, vernalization prevents flowering in winter. In Arabidopsis, FLOWERING LOCUS C or FLC is the key repressor during vernalization, while in monocots vernalization is regulated through VRN1, VRN2 and VRN3 (or FLOWERING LOCUS T). Interestingly, VRN genes are not homologous to FLC but FLC homologs are found to have a significant role in vernalization response in cereals. The presence of FLC homologs in monocots opens new dimensions to understand, compare and retrace the evolution of vernalization pathways between monocots and dicots. In this review, we discuss the molecular mechanism of vernalization-induced flowering along with epigenetic regulations in Arabidopsis and temperate cereals. A better understanding of cold-induced flowering will be helpful in crop breeding strategies to modify the vernalization requirement of economically important temperate cereals. 相似文献
10.
Pu Xue Tong Si Shekhar Mishra Linzixuan Zhang Kisurb Choe Jonathan V. Sweedler Huimin Zhao 《Biotechnology and bioengineering》2020,117(7):2131-2138
Microbial cell factories have been extensively engineered to produce free fatty acids (FFAs) as key components of crucial nutrients, soaps, industrial chemicals, and fuels. However, our ability to control the composition of microbially synthesized FFAs is still limited, particularly, for producing medium-chain fatty acids (MCFAs). This is mainly due to the lack of high-throughput approaches for FFA analysis to engineer enzymes with desirable product specificity. Here we report a mass spectrometry (MS)-based method for rapid profiling of MCFAs in Saccharomyces cerevisiae by using membrane lipids as a proxy. In particular, matrix-assisted laser desorption/ionization time-of-flight (MALDI-ToF) MS was used to detect shorter acyl chain phosphatidylcholines from membrane lipids and a higher m/z peak ratio at 730 and 758 was used as an indication for improved MCFA production. This colony-based method can be performed at a rate of ~2 s per sample, representing a substantial improvement over gas chromatography-MS (typically >30 min per sample) as the gold standard method for FFA detection. To demonstrate the power of this method, we performed site-saturation mutagenesis of the yeast fatty acid synthase and identified nine missense mutations that resulted in improved MCFA production relative to the wild-type strain. Colony-based MALDI-ToF MS screening provides an effective approach for engineering microbial fatty acid compositions in a high-throughput manner. 相似文献