Bacterial capturing and biodegradation of fine particles in the ocean

在海洋表层，每毫升海水中大约有一千到一亿个半径小于0.5微米的细小颗粒。这些微粒是如何代谢的？细菌是如何与这些颗粒相互作用的？细菌与细小颗粒和大表面的相互作用有什么不同？这个项目就是为了回答这些问题而进行的。经过三年的研究，明确了以下几点。首先，在利用顺磁珠的一系列新方法之后，提出了细菌颗粒捕获的概念。其次，在不同的物理化学条件下，考察了海洋细菌鱼弧菌对微细颗粒的释放。结果表明，该菌能产生类似病毒的核酸颗粒，并可能作为基因转移的介体。第三，研究了表面聚合物层对细菌与大颗粒或附着相互作用的重要性，并阐明了排斥能的参与。

In surface layer of the ocean, there are approximately ten to one hundred million of fine particles of which radius is less than 0.5 micron in one ml of seawater. How those particles are metabolized? How do bacteria interact with those particles? What is the difference between the bacterial interaction with fine particles and large surfaces? This project was conducted to answer these questions. After three years research, the followings have been clarified. First, the concept of "bacterial particle capturing" was proposed after a series of newly developed method using paramagnetic beads. Second, the release of fine particles from marine bacterium, Vibrio fisheri was examined under various physicochemical conditions. It was clarified that the bacterium produce virus like particles containing nucleic acid and may serve as mediator of gene transfer. Third, the importance of surface polymer layers for bacterial interaction with large particles or attachment were investigated and the involvement of repulsion energy was clarified.