Development of breeding technology of microorganisms for environmantal purification using natural propagation of genotypes.

本研究项目的目的是开发利用基因型自然繁殖的环境净化微生物育种技术。该研究旨在建立基因工程的新概念。在这个项目中，研究人员调查了环境净化基因自然繁殖的遗传媒介。本项目还研究了提高天然转基因效率的技术方法，取得了以下研究成果。(1)先前分离的厌氧抗汞细菌和新分离的需氧抗汞细菌都编码II类转座子上的抗汞基因操纵子。(2)这些分离的细菌的染色体中存在II类转座子。在来自好氧分离物的转座子中，细菌内含子也被编码，并且这显示了内含子对于耐汞遗传模块的大范围繁殖的一些作用。(3)对包括抗汞基因模块在内的转座子及其邻近区域进行测序，以寻找其它转座因子。(4)开发了分析方法和实验系统来研究细菌物种以外的遗传繁殖机制。细菌交配的基因转移和剪接和细菌内含子归巢的实验方法的开发。这些方法被认为是有用的澄清细菌基因转移的机制，开发环境生物技术的新概念。

The purpose of the research project was to develop a technology for breeding technology of microorganisms for environmental purification using natural propagation of genotypes. The research was conducted to establish new concept in genetic engineering. In this project, the researchers investigated genetic media for the natural propagation of environmental purification genes. Technical method for enhancement of the natural gene transfer was also investigated in this project.The results obtained in this research project were as follows.(1) Both previously isolated anaerobic mercury-resistant bacteria and newly isolated aerobic mercury-resistant bacteria encode mercury resistance gene operons on a class II transposon.(2) The class II transposon exist in the chromosomes of those isolated bacteria. In the transposon from the aerobic isolate, a bacterial intron is also encoded, and this shows some role of the intron for wide-range propagation of the mercury resistance genetic modules.(3) The transposon including the mercury resistance genetic module and its vicinity was sequenced to fined other transposable elements.(4) Analytical methods and experimental systems to investigate the mechanism of the genetic propagation beyond bacterial species was developed. Experimental methods of bacterial mating for gene transfer and splicing and homing of the bacterial intron were developed. These methods are considered to be useful for clarification of the mechanism of bacterial gene transfer to develop new concepts for environmental biotechnology.