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1.
An analysis of the turnover of the major phospholipids of Micrococcus cerificans growing or nongrowing cultures. The turnover rates of (14)C-PE and (14)C-PE were 61.5% of the total phospholipid, exhibited no significant rate of turnover in either growing or nongrowing cultures. The turnover rates of PE-(14)C and PE-(32)P were 3.2% per hr and 1.2% per hr, respectively. Phosphatidylglycerol (PG) exhibited a turnover rate of 11% and 7.7% per hr for (14)C and (32)P, respectively, indicating an extremely slow metabolism. PG metabolism was examined in greater detail, and the data indicated a preferential 75% incorporation of glycerol-1,3-(14)C into the unacylated portion of the PG molecule. The turnover of cardiolipin (CL) was extremely slow in growing cells whereas nongrowing cells exhibited a 30% and 36% increase per hr for (14)C-Cl and (14)C-CL, respectively. Glycerol-1,3-(14)C was not converted to phospholipid fatty acid carbon; all radioactivity appeared only in the water-soluble backbone of the phospholipids. The kinetics of assimilation of hexadecane-1-(14)C into cellular lipids is presented. Radioactivity in neutral lipid increased approximately sevenfold over the growth cycle, whereas radioactivity in phospholipid increased 50-fold during the same time period. The incorporation of radioactive fatty acids derived from the direct oxidation of hexadecane-1-(14)C demonstrated differential kinetics of assimilation into PE, PG, and CL. The results indicated a rapid turnover of phospholipid fatty acids in M. cerificans growing at the expense of hexadecane. 相似文献
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A process is described for the microbial degradation of cholesterol and plant sterols, to produce androsta-1, 4-diene-3, 17-dione and androst-4-ene-3, 17-dione, by two newly isolated bacteria designated Mycobacterium sp. NRRL B-3683 and Mycobacterium sp. NRRL B-3805. These myocbacteria produce substantial amounts of 17-ketonic compounds without appreciable degradation of the steroid nucleus. No ring degradation inhibitory agents are necessary. The first microbiological production of 20alpha-hydroxymethylpregna-1, 4-dien-3-one is also reported. 相似文献
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Organisms of the genera Pseudomonas, Chromobacterium, and Bacillus capable of degrading asphalt were isolated by enrichment cultures. The asphalt degradation by these organisms varied from 3 to 25% after incubation for 1 week. The effects of temperature, pH, and atmosphere of incubation on asphalt degradation were investigated and were shown to vary with different organisms on the same substrate. 相似文献
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The microbial degradation of low-molecular-weight polydimethylsiloxanes was investigated through laboratory experiments. Octamethylcyclotetrasiloxane was found to be biodegraded under anaerobic conditions in composted sewage sludge, as monitored by the occurrence of the main polydimethylsiloxane degradation product, dimethylsilanediol, compared to that found in experiments with sterilized control samples. 相似文献
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The distribution of phospholipids derived from Micrococcus cerificans was determined under a variety of nutritive conditions. Cells were grown with hexadecane, heptadecane, or acetate serving as the sole carbon source. Total lipid was isolated by chloroform-methanol extraction, and the phospholipid fraction was isolated by silicic acid column chromatography. The phospholipids were characterized by silicic acid chromatography, by thin-layer chromatography, and by identification of water-soluble products resulting from acid hydrolysis of purified phospholipids. Major phospholipids characterized were phosphatidylethanolamine, phosphatidylglycerol, and cardiolipin. Minor phospholipids were phosphatidylglycerol phosphate and phosphatidylserine. Trace amounts of methylated derivatives of phosphatidylethanolamine were determined by incorporation of 14C from 14C-methylmethionine. These experiments demonstrated the presence of phosphatidyl-N-methylethanolamine, phosphatidyl-N,N′-dimethylethanolamine, and phosphatidylcholine in trace quantities. Pulse labeling with 14C-serine demonstrated the direct incorporation of serine into phosphatidylserine followed by decarboxylation to phosphatidylethanolamine. 相似文献
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Measurements of biological O(2) demand showed that normal alkanes containing up to 44 carbon atoms were metabolized by microorganisms. 相似文献
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Mono-, di-, tri-, and tetraethylene glycols and polyethylene glycols (PEG) with molecular weight up to 20,000 were degraded by soil microorganisms. A strain of Pseudomonas aeruginosa able to use a PEG of average molecular weight 20,000 was isolated from soil. Washed cells oxidized mono and tetraethylene glycols, but O2 consumption was not detectable when such cells were incubated for short periods with PEG 20,000. However, the bacteria excreted an enzyme which converted low- and high-molecular-weight PEG to a product utilized by washed P. aeruginosa cells. Gas chromatography of the supernatant of a culture grown on PEG 20,000 revealed the presence of a compound co-chromatographing with diethylene glycol. A metabolite formed from PEG 20,000 by the extracellular enzyme preparation was identified as ethylene glycol by combined gas chromatography-mass spectrometry. 相似文献
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Three bacterial strains have been isolated that differ in their ability to degrade polyethylene glycols (PEGs). Strains R and O showed a marked preference for growth on the low and high molecular weight PEGs, respectively, while strain Z utilized mono-ethylene glycol only. The partial degradation of PEG 200 by strains R and O was studied in some detail and the results suggested that those components of the mixture that were not utilized were converted into acidic derivatives which accumulated in the medium. 相似文献
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An actinomycete, Nocardia sp. strain 835A, grows well on unvulcanized natural rubber and synthetic isoprene rubber, but not on other types of synthetic rubber. Not only unvulcanized but also various kinds of vulcanized natural rubber products were more or less utilized by the organism as the sole source of carbon and energy. The thin film from a latex glove was rapidly degraded, and the weight loss reached 75% after a 2-week cultivation period. Oligomers with molecular weights from 104 to 103 were accumulated during microbial growth on the latex glove. The partially purified oligomers were examined by infrared and 1H nuclear magnetic resonance and 13C nuclear magnetic resonance spectroscopy, and the spectra were those expected of cis-1, 4-polyisoprene with the structure, OHC—CH2—[—CH2—C(—CH3)=CH —CH2—]n—CH2—C(=O)— CH3, with average values of n of about 114 and 19 for the two oligomers. 相似文献
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α-Glucoisosaccharinic acid (GISA), a major by-product of kraft paper manufacture, was synthesized from lactose and used as the carbon source for microbial media. Ten strains of aerobic bacteria capable of growth on GISA were isolated from kraft pulp mill environments. The highest growth yields were obtained with Ancylobacter spp. at pH 7.2 to 9.5. GISA was completely degraded by cultures of an Ancylobacter isolate. Ancylobacter cell suspensions consumed oxygen and produced carbon dioxide in response to GISA addition. A total of 22 laboratory strains of bacteria were tested, and none was capable of growth on GISA. GISA-degrading isolates were not found in forest soils. 相似文献
11.
基于微生物同化作用的D-丙氨酸生产工艺研究 总被引:1,自引:0,他引:1
以L-丙氨酸为唯一碳氮源,从采集的若干土壤中初筛出能够降解L-丙氨酸的菌株;再以D-丙氨酸为唯一碳氮源,复筛出降解L-丙氨酸而不降解D-丙氨酸的菌株。依据菌种对DL-丙氨酸的不对称降解活性,筛选出具有最高的L-丙氨酸降解活性的菌株,并对菌株同化L-丙氨酸的反应条件进行了研究。结果表明:编号为ALA-D82的菌株具有最高的降解L-丙氨酸的能力,经鉴定为酵母菌属。在30℃,控制pH6.0,通气比1:1(V/V)和转速900 r.min-1的条件下,L-丙氨酸降解的速度最大。在最适条件下,1500 g DL-丙氨酸分两部分添加入7 L的反应液中。反应72 h后溶液中的L-丙氨酸被完全降解,提取得到D-丙氨酸晶体,产率和光学纯度分别达到92.13%和99%。 相似文献
12.
微生物降解联苯的研究进展 总被引:1,自引:0,他引:1
联苯是一种有机污染物,在自然环境中很难分解。目前研究的降解方法中,微生物降解最有潜力。微生物法处理成本低、效果好、无二次污染,且操作简单,能够实现真正意义上的再循环。该文对国内外开展的微生物降解联苯的相关研究进行了综述,对联苯降解的菌群、代谢途径及其关键酶进行了详细的阐述,指出了微生物降解联苯存在的关键问题是修复效率低,高效菌株的筛选、基因工程菌的构建及其多种修复技术的结合是今后研究的方向。 相似文献
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Microbial Degradation of Diphenylamine Under Anoxic Conditions 总被引:2,自引:0,他引:2
Diphenylamine (DPA) was cometabolically degraded in anoxic sediment-water batch enrichments and in cultures of newly isolated
sulfate-reducing bacteria. In gas chromatography–mass spectrometry (GC-MS) measurements, aniline was identified as a major
breakdown product of the diphenylamine structure. After its identification, aniline was quantified by reversed phase high
pressure liquid chromatography (HPLC). The fate of the other carbon ring system remained unclear, because benzene (as a product
of reductive cleavage), phenol (as a product of hydrolytic cleavage), and/or other ring cleavage products of diphenylamine
were not observed in our experiments with the methods employed.
Received: 20 May 1997 / Accepted: 25 June 1997 相似文献
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Triadimenol is a widely used triazole fungicide and consists of four stereoisomers with 1R,2S, 1S,2R, 1R,2R, and 1S,2S configurations. The trans‐enantiomeric pair (1R,2S‐isomer and 1S,2R‐isomer) is also called triadimenol‐A and the cis‐enantiomeric pair (1R,2R‐isomer and 1S,2S‐isomer) triadimenol‐B. In this study, the stereoselective degradation and chiral stability of triadimenol in two soils were investigated in details. The dissipation of technical triadimenol, a 6:1 mixture of triadimenol‐A and triadimenol‐B, showed significant epimerization from triadimenol‐A to triadimenol‐B occurred along with the dissipation process. The degradation exhibited some stereoselectivity, resulting in a concentration order of 1S,2S > 1R,2R > 1R,2S > 1S,2R or 1S,2S > 1R,2R > 1S,2R > 1R,2S at the end of the 100 days incubation for Baoding soil or Wuhan soil, respectively. Further incubation of triadimenol‐B revealed no epimerization, i.e. triadimenol‐B was configurationally stable in soil, and 1R,2R‐triadimenol degraded slightly slower in the former part and slightly faster in the later part of the incubation than 1S,2S‐triadimenol. Moreover, by incubation of enantiopure 1S,2R‐triadimenol and 1R,2S‐triadimenol, the results documented the epimerization for each enantiomer occurred at both C‐1 and C‐2 positions. Finally, the present work also documented that the enantiomerization reaction for all the four stereoisomers was nearly negligible in the soils. Chirality 25:355‐360:, 2013. © 2013 Wiley Periodicals, Inc. 相似文献
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Malakhova D. V. Egorova M. A. Leontieva M. R. Elcheninov A. G. Panova T. V. Aleksandrov Yu. D. Tsavkelova E. A. 《Microbiology》2023,92(1):83-93
Microbiology - Resistance to biodegradation, which is among the most advantageous features of synthetic polymers, is also the reason for their accumulation in the environment and therefore... 相似文献