低湿度表面的海洋附着细菌对厚壳贻贝附着的影响

Effects of bacterial biofilms formed on low surface wettability on settlement of plantigrades of the mussel Mytilus coruscus

从低湿度表面形成自然微生物被膜中分离和纯化出9株海洋附着细菌,并进行细菌16S rDNA基因序列的鉴定以确定其菌名;在18℃、黑暗条件下培养48h后形成单一菌株的微生物被膜,研究了细菌不同初始密度条件下形成微生物被膜的终密度变化及其对厚壳贻贝Mytilus coruscus稚贝附着的影响。同时,将获得的序列与有亲缘关系的序列用Mega软件的CLUSTALW程序进行序列比对和系统发育分析。结果表明:所有测试海洋附着细菌形成微生物被膜的最终密度随初始密度的增加而增加;9株海洋细菌均能不同程度地促进厚壳贻贝稚贝的附着,其中Bacillus sp.2诱导活性最高,其诱导稚贝的附着率为68%;除Pseudoalteromonas sp.3微生物被膜终密度与稚贝附着无显著相关性外(P>0.05),其余8株海洋细菌所形成的微生物被膜终密度与稚贝附着均呈显著相关性(P<0.05);系统发育分析表明,微生物被膜终密度对稚贝附着的诱导活性与细菌种属无关。研究表明,低湿度表面的海洋附着细菌对厚壳贻贝的附着有明显的促进作用,本研究结果对于今后开展厚壳贻贝稚贝的附着机制研究奠定了基础。

The marine bacteria were isolated from the biofilms developed on the low surface wettability and the effects of bacterial biofilms on settlement of Mytilus coruscus plantigrades were investigated in a laboratory. The phylogenetic tree derived from the selected 16S rDNA sequence was constructed and the genetic distance was calculated. Of the 9 isolates,all bacterial biofilms showed inducing activity,the maximal settlement（ 68%） in Bacillus sp.2 biofilm. Among the 8 bacterial species that demonstrated inducing activity,bacterial density was significantly correlated with the inducing activity for each strain,with the exception of Pseudoalteromonas sp. 3. The density of monospecific bacterial biofilms was found to be increased with the increase in initial incubation density. The inducing activity of individual bacterial isolates was not correlated with the phylogenetic relationship. Thus,marine bacteria derived from biofilms developed on low surface wettability led to promote the settlement of plantigrades of the mussel M.coruscus. This finding is important to understand the mechanism of settlement of M. coruscus plantigrades.