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Analysis of different processes of gene transfer in aquatic ecosystems using the Aquatron

使用 Aquatron 分析水生生态系统中基因转移的不同过程

基本信息

批准号：
16207001
负责人：
KAWABATA Zen'ichiro
金额：
$ 31.62万
依托单位：
Research Institute for Humanity and Nature (2005-2006)Kyoto University (2004)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

项目摘要

1 Bacterial DNAs which were released from their cells by phage infection are potential resources for gene transfer by natural transformation. Number of bacteria which took a dissolved plasmid with GFP gene in their cells by natural transformation is 100 times as great as that of bacteria which expressed GFP gene. This indicates natural transformation might take place in natural environments with a higher frequency than we have regarded so far.2 Tetrahymena thermophila, a bacteriovore, inhibited a conjugal transfer from Escherichia coli to Pseudomonas stutzeri by predation on them, and the coexistence of T. thermophila with Microcystis aeruginosa, a producer, enhanced the inhibition.3 A mini tranposon (mini Tn) was constructed by the transposon Tn MERI1 coding the mercury resistance genes. The mini Tn was introduced into a non-conjugal plasmid. Then this plasmid was transferred into Eshericia coli DH1with conjugal plasmid R338. It was observed the mini Tn transposed into R338 and then the mini Tn on R338 was transferred to Eshericia coli HB101 by conjugation. This suggested the possibility a conjugal transfer through transposition among replicon in a bacterial cell.4 DNA sequences of the Tn MERI1 type transposon, IR and DR reiterated sequences on mercury resistance bacterial chromosome were analyzed. This analyses revealed that worldwide gene transfer by transposon took place among bacteria.5 A community dominated with Microcystis aeruginosa, cyanobacteria, in the Aquatron reduced an infectivity of phage EC 10.

通过噬菌体感染从细胞中释放出来的细菌dna是通过自然转化进行基因转移的潜在资源。通过自然转化将含有GFP基因的溶解质粒带入细胞的细菌数量是表达GFP基因的细菌数量的100倍。这表明自然环境中发生的自然转变的频率可能比我们迄今所认为的要高嗜热四膜菌（Tetrahymena thermoophila）通过捕食大肠埃希氏菌（Escherichia coli）向stutzeri假单胞菌（Pseudomonas stutzeri）的结合，抑制了大肠埃希氏菌向假单胞菌（pseudomichia stutzeri）的转移，嗜热四膜菌与产生假单胞菌（Microcystis aeruginosa）的共存增强了这种抑制作用利用转座子Tn MERI1编码抗汞基因，构建了一个迷你转座子（mini Tn）。将迷你Tn引入非共轭质粒。将该质粒与偶联质粒R338一起转移到大肠杆菌dh1中。观察到微型Tn转置到R338上，R338上的微型Tn通过偶联转移到大肠杆菌HB101上。这表明在细菌细胞中通过复制子之间的转位进行配偶转移的可能性分析了耐汞细菌染色体上Tn MERI1型转座子、IR和DR重复序列的DNA序列。结果表明，细菌间通过转座子进行了世界性的基因转移在Aquatron中以铜绿微囊藻和蓝藻为主的群落降低了噬菌体ec10的传染性。