共查询到20条相似文献,搜索用时 15 毫秒
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The production of L-asparaginase by two mutants ofSerratia marcescens grown on 14 different media was studied. The enzyme content increased from trace levels to 2.4 international units per ml
when the organisms were grown in glycerol-peptone yeast extract medium. Glucose was the best carbon source under aerobic conditions.
The enzyme content increased when L-asparagine was present in the growth medium. 相似文献
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Linawati Hardjito Anwar Huq Rita R. Colwell 《Biotechnology and Bioprocess Engineering》2002,7(2):100-104
Serratia marcescens biovar A2/A6, isolated from an Indonesian freshwater source, was identified based on extensive morphological, biochemical
and genetic characterization. Formation of pigment was found to be strongly influenced by environmental conditions. Placket-Burman
design was used to analyze the effect of carbon and nitrogen sources. Based on results of physiological and biochemical studies,
the optimum conditions for growth and pigment formation were incubation 30°C in a neutral to slightly alkaline medium containing
lactic acid and beef extract. 相似文献
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A biosurfactant exhibiting excellent emulsification activity and surface properties was isolated during growth ofSerratia marcescens on 2% (w/v) sucrose. Reduction in surface tension values and increase in the yield of biosurfactant during the late log phase
of growth indicates that the biosurfactant is a secondary microbial metabolite. The biosurfactant formed stable emulsions
with a wide variety of hydrocarbons. The isolated surface-active compound has a potential application in enhanced oil recovery
and is stable over a wide range of temperatures (10-120‡C) and pH (2-12). This is the first report of effective and stable
emulsion formation by a strain ofSerratia marcescens. 相似文献
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A strain of Serratia marcescens showing the ability to degrade caffeine and other methylxanthines was isolated from soil under coffee cultivation. Growth was observed only with xanthines methylated at the 7 position (caffeine, 1,3,7-dimethylxanthine; paraxanthine, 1,7-dimethylxanthine; theobromine, 3,7-dimethylxanthine and 7-methylxanthine). Paraxanthine and theobromine were released in liquid medium when caffeine was used as the sole source of carbon and nitrogen. When paraxanthine or theobromine were used, 3-methylxanthine, 7-methylxanthine, and xanthine were detected in the liquid medium. Serratia marcescens did not grow with theophylline (1,3-dimethylxanthine), 1-methylxanthine, and 3-methylxanthine, and poor growth was observed with xanthine. Methyluric acid formation from methylxanthines was tested in cell-free extracts by measuring dehydrogenase reduction of tetrazolium salt in native-polyacrylamide gel electrophoresis gel. Activity was observed for all methylxanthines, even those with which no bacterial growth was observed. Our results suggest that in this strain of S. marcescens caffeine is degraded to theobromine (3,7-dimethylxanthine) and/or paraxanthine (1,7-dimethylxanthine), and subsequently to 7-methylxanthine and xanthine. Methyluric acid formation could not be confirmed.
Correspondence to: Paulo Mazzafera. 相似文献
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G P Sovetova A T Kravchenko S G Dzagurov 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1979,(1):79-83
High diphtheria exotoxin concentrations induced irreversible injuries to all the cultures under study (L, HeLa, spcv pzM). However, its final titres in the mentioned cells differed. HeLa and pzM cells, being highly sensitive, can be recommended for titration of dipheria exotoxin, instead of the expensive guinea pig tests. Low (subtoxic) doses produced cytoproliferative action and caused changes of the cell properties. 相似文献
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Pigment formation in L-forms of Serratia marcescens 总被引:5,自引:0,他引:5
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Radiation induced formation of giant cells inSaccharomyces uvarum III: Effect of X-rays on nuclear division 总被引:1,自引:0,他引:1
Baumstark-Khan Christa Rink H. Zimmermann H. -P. 《Radiation and environmental biophysics》1986,25(1):23-30
Summary Spindle formation and nuclear division of budding and irradiated yeast cells (Saccharomyces uvarum) was investigated by fluorescence microscopy of protoplasted cells. Protoplasts were treated with antitubulin antibodies and DAPI, a fluorescent dye staining DNA. In budding yeast cells, duplication of spindle pole bodies as well as formation of complete 1-µm spindles and elongated 8-µm spindles were documented. In X-irradiated cells, spindle pole bodies were duplicated as well, forming the complete 1-µm spindle. Nuclei of giant cells have lost the elongation ability and remain in a normal G2-phase state, thus preventing nuclear as well as cellular division. 相似文献