一株溶藻菌Zobellella sp.B307对太平洋亚历山大藻的溶藻特性及作用机制研究OA北大核心CSTPCD

In order to study the algicidal mechanism of algicidal bacteria on red tide dinoflagellate,a salt-tolerant bacterium Zobellella sp.B307 with algicidal activity to the Alexandrium pacificum was isolated from the sediments of Jiaozhou Bay.To explore the algicidal mechanism of Zobellella sp.B307,we investigated its effect on the cellular structure,physiologyl and molecular mechanism of A.pacifi-cum.The results showed that the inhibition mechanism of the strain was indirect lytic effects causing by extracellular active substances.And after 72 h cultivation with bacterium addition,the algicidal rate reached up to 91%,revealing its strong algicidal activity against A.pacificum.Meanwhile,we ob-served cell wall damage,chlorophyll-a and total protein contents decrease,and the excessive production of reactive oxygen species(ROS),superoxide dismutase(SOD)and catalase(CAT).It indicated that the serious oxidative damage caused by algae-lysing substances was the direct cause of A.pacificum death.The expression level of heat shock protein(HSP)gene was significantly upregulated,suggesting that algae-lysing substances could induce the production of HSP,and the combined effects of highly ex-pressed HSP and highly activited antioxidant system of A.pacificum could eliminate ROS and alleviate the algae cells damage caused by oxidative stress.In addition,the expression of A.pacificum clathrin gene was significantly upregulated,indicating algae cells could enhanced heterotrophic function to com-pensate the loss of photosynthesis caused by algae-lysing substances.The results of this study will con-tribute to explain the newly founded relationship between bacteria and algae,and explore the new bio-logical methods of red tide control.