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Growth inhibition by alpha-aminoadipate and reversal of the effect by specific amino acid supplements in Saccharomyces cerevisiae 总被引:5,自引:4,他引:1 下载免费PDF全文
The growth of Saccharomyces cerevisiae wild-type strain X2180 in minimal medium was inhibited by the addition of higher-than-supplementary levels of alpha-aminoadipate. This inhibitory effect was reversed by the addition of arginine, asparagine, aspartate, glutamine, homoserine, methionine, or serine as single amino acid supplements. Mutants belonging to the lys2 and lys14 loci were able to grow in lysine-supplemented alpha-aminoadipate medium, although not as well as when selected amino acids were added. Growth in alpha-aminoadipate medium by all strains was accompanied by an accumulation of alpha-ketoadipate. Glutamate:keto-adipate transaminase levels were derepressed two- to fivefold in lys2 mutants using alpha-aminoadipate as a nitrogen source. Wild-type strain X2180 growing in amino acid-supplemented AA medium exhibited higher levels of alpha-aminoadipate reductase. Mutants unable to use alpha-aminoadipate without amino acid supplementation were obtained by treatment of lys2 strain MW5-64 and were shown to have glutamate: ketoadipate transaminase activity and to lack alpha-aminoadipate reductase activity. Altered cell morphologies, including increased size, multiple buds, pseudohyphae, and germ tubes, evidenced by cells grown in alpha-aminoadipate medium suggest that higher-than-supplementary levels of alpha-aminoadipate result in an impairment of cell division. 相似文献
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An α-agarase was isolated from a Gram-negative marine bacterium that liquefies agar. The enzyme was purified by chromatography on diethylaminoethyl-cellulose (HO? form) buffered at pH 7.2. The purified enzyme specifically cleaves (1 →3)-α-L-linkages in agarose, yielding a homologous series of agaro-oligosaccharides. Agarotetraitol and agarohexaitol were characterized. 相似文献
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Rashi Tyagi Salila Pradhan Annapurna Bhattacharjee Shubham Dubey Shilpi Sharma 《Journal of applied microbiology》2022,133(2):254-272
Abiotic stresses detrimentally affect both plant and soil health, threatening food security in an ever-increasing world population. Sustainable agriculture is necessary to augment crop yield with simultaneous management of stresses. Limitations of conventional bioinoculants have shifted the focus to more effective alternatives. With the realization of the potential of rhizospheric microbiome engineering in enhancing plant's fitness under stress, efforts have accelerated in this direction. Though still in its infancy, microbiome-based engineering has gained popularity because of its advantages over the microbe-based approach. This review briefly presents major abiotic stresses afflicting arable land, followed by an introduction to the conventional approach of microbe-based enhancement of plant attributes and stress mitigation with its inherent limitations. It then focuses on the significance of the rhizospheric microbiome and possibilities of harnessing its potential by its strategic engineering for stress management. Further, success stories related to two major approaches of microbiome engineering (generation of synthetic microbial community/consortium, and host-mediated artificial selection) pertaining to stress management have been critically presented. Together with bringing forth the challenges associated with the wide application of rhizospheric microbiome engineering in agriculture, the review proposes the adoption of a combinational scheme for the same, bringing together ecological and reductionist approaches for improvised sustainable agricultural practices. 相似文献
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P.W. Ramteke J.W. Bhattacharjee S.P. Pathak N. Kalra 《Journal of applied microbiology》1992,72(4):352-356
P.W. RAMTEKE, J.W. BHATTACHARJEE, S.P. PATHAK AND N. KALRA. 1992. The total and thermotolerant coliform counts in rural drinking water derived from ground water, piped supplies and surface water are reported for a number of areas in India. To evaluate these counts as indicators of recent faecal contamination the total coliforms and thermotolerant coliforms isolated have been identified. Thermotolerant Escherichia coli formed 11.7% of the total coliforms and 75.1% of the thermotolerant coliforms. Citrobacter sp. (20.4%) and Klebsiella sp. (50.9%) were the other common total coliforms isolated and, among the thermotolerant coliforms, Klebsiella sp. (16.4%) was the only other organism frequently encountered. The total coliform counts were significantly correlated with water temperature. The applicability in tropical areas of standards developed for temperate climates is discussed. 相似文献