Isolation of algicidal bacteria chemotaxiing toward blooming microalgae and its application as a "missile" for the prevention of red tide

本研究试图分离出能杀灭特定藻种或对特定藻种趋化作用的溶藻细菌，用于赤潮的微生物防治。在2年的研究中，共分离到88株溶藻细菌，其中23株仅能杀灭米氏裸藻。我们还分离出12个能动的溶藻菌株，其中，6个细菌表现出对赤潮浮游植物的趋化特性。其中一株仅被Chattonella antiqua吸引的菌株对两种G. mikimotoi和C.当它和一种藻类混合时。但将该菌接种到两种藻类的混合培养物中，则抑制了C. antiqua，对G.御木本耽搁了。这些结果表明，细菌对微藻的物种特异性抑制的一部分，将能够被解释为溶藻细菌的趋化特性，这种细菌可能是有用的，通过使用它们作为“导弹”来防止赤潮。

We tried to isolate algicidal bacteria killing some restricted taxonomical groups of blooming microalgae, or those chemotaxiing toward some special algal species, for the microbiological prevention of red tides. During the study for 2 years, 88 strains of algicidal bacteria were newly isolated, and 23 strains out of 88 killed only Gymnodinium mikimotoi, a noxious red tide phytoplankton. We also isolated 12 motile algicidal strains, and among those, 6 bacteria showed chemotactic properties toward either of red tide phytoplankton species. One strain attracted only by Chattonella antiqua showed killing ability against both G. mikimotoi and C. antiqua when it was mixed with one algal species. However, when this bacterium was inoculated into mixed cultures of the two alagal species, it suppressed the growth of C. antiqua at first and inhibition against G. mikimotoi was delayed. These results suggest that a part of species-specific suppression against microalgae by bacteria would be able to be explained by chemotactic properties of algicidal bacteria, and that such bacteria could be useful for preventing red tide by applying them as a "missile".