Microbial releases : viruses, bacteria, fungi最新文献_第2页

Glutamate uptake and synthesis by Escherichia coli cells in seawater: effects on culturability loss and glycinebetaine transport. 海水中大肠杆菌细胞对谷氨酸的吸收和合成:对培养损失和甘氨酸运输的影响。

Microbial releases : viruses, bacteria, fungi Pub Date : 1993-06-01

M J Gauthier, G N Fatau, P M Munro, R L Clément

{"title":"Glutamate uptake and synthesis by Escherichia coli cells in seawater: effects on culturability loss and glycinebetaine transport.","authors":"M J Gauthier, G N Fatau, P M Munro, R L Clément","doi":"","DOIUrl":"","url":null,"abstract":"In filtered natural seawater supplemented with potassium glutamate, the ability of Escherichia coli MC4100 cells to grow on a complex medium was enhanced as a logarithmic function of the external glutamate concentration. By comparison, a glutamate-respiring strain of E. coli exhibited a greater decline in culturability in seawater, suggesting a protective influence of the accumulated amino acid. Potassium glutamate increased the uptake of 14C-glycinebetaine by E. coli MC4100 cells in seawater and enhanced the protective effects of the betaine against culturability loss, possibly by increasing the expression of the ProU transport system. This bacterium apparently was able to synthesize glutamate because a protective effect (i.e. a lower culturability loss) was observed in seawater when supplemented with precursor compounds (2-oxoglutarate and glutamine). The combination of 2-oxoglutarate and glutamine resulted in the greatest protection of cells, possibly due to the synthesis of glutamate through glutamine 2-oxoglutarate amino transferase activity. The possible influence of glutamate and its precursors on survival of E. coli cells in the natural marine environment is considered, since glutamate, glutamine and betaines have been found in marine coastal waters and sediments.","PeriodicalId":77262,"journal":{"name":"Microbial releases : viruses, bacteria, fungi","volume":"2 1","pages":"53-9"},"PeriodicalIF":0.0,"publicationDate":"1993-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19248648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Identification of Azospirillum species by RFLP and pulsed-field gel electrophoresis. 利用RFLP和脉冲场凝胶电泳技术鉴定氮螺旋菌的种类。

Microbial releases : viruses, bacteria, fungi Pub Date : 1993-06-01

C Gündisch, G Kirchhof, M Baur, W Bode, A Hartmann

引用次数: 0

Synergistic toxicity of IFN-gamma-producing Escherichia coli K12 cells. 产生ifn - γ的大肠杆菌K12细胞的协同毒性。

Microbial releases : viruses, bacteria, fungi Pub Date : 1993-06-01

R Dijkmans, F Cornette, S Kreps, E Martens, J Vankerkom, M Mergeay, A Billiau

{"title":"Synergistic toxicity of IFN-gamma-producing Escherichia coli K12 cells.","authors":"R Dijkmans, F Cornette, S Kreps, E Martens, J Vankerkom, M Mergeay, A Billiau","doi":"","DOIUrl":"","url":null,"abstract":"Genetically modified microorganisms (GMMs) are frequently used as producers of mammalian immunomodulatory proteins, e.g. interferons and interleukins. Here we have examined the question of whether such GMMs interact in a way different from that of their non-modified parent micro-organisms with mammalian antimicrobial defence systems. As a typical GMM host micro-organism we used Escherichia coli K12, and as a typical immunomodulatory protein produced by a GMM we used mouse interferon-gamma (MuIFN-gamma). Two experimental systems are described in which synergistic \"toxic\" biological effects are induced by a combined treatment with E. coli and MuIFN-gamma but not, or less so, by the parental strain and the recombinant protein separately. First, it is shown that the IFN-gamma-producing GMM, or mixtures of E. coli cells and IFN-gamma, are cytolytic for mouse embryo fibroblastoid cells (MEF), whereas no cell killing occurs in MEF cultures treated with control E. coli cells or in those treated with bacteria-free recombinant IFN-gamma. Second, it is demonstrated that intraperitoneal injection in mice of high but not low numbers of control E. coli K12 cells induces a shock-like mortality, whereas co-injection with IFN-gamma induces killing at low numbers. IFN-gamma-producing E. coli cells cause a mortality rate that does not differ from that of control E. coli cells, probably because in these experimental conditions the level of recombinant MuIFN-gamma per cell is insufficiently high. Taken together, these data indicate that synergistic toxic effects induced by bacteria and their recombinant products can occur and may in certain situations enhance the intrinsic toxic capacity of the GMM. Synergistic toxic effects may thus be of relevance for identifying the safety level that should be employed when working with GMMs.","PeriodicalId":77262,"journal":{"name":"Microbial releases : viruses, bacteria, fungi","volume":"2 1","pages":"23-8"},"PeriodicalIF":0.0,"publicationDate":"1993-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19249416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Rapid method for purification of soil DNA for hybridization and PCR analysis. 用于杂交和PCR分析的土壤DNA快速纯化方法。

Microbial releases : viruses, bacteria, fungi Pub Date : 1993-06-01

R Dijkmans, A Jagers, S Kreps, J M Collard, M Mergeay

引用次数: 0

Deliberate release of a recombinant vaccinia-rabies virus for vaccination of wild animals against rabies. 故意释放重组牛痘-狂犬病毒用于野生动物狂犬病疫苗接种。