中湿度表面的海洋细菌对厚壳贻贝稚贝附着的影响

为研究自然微生物膜中海洋细菌对厚壳贻贝稚贝附着的影响,通过海洋贝类生物学、分子微生物生态学等手段调查附着基表面湿度、微生物膜的密度以及细菌种属系统发育与厚壳贻贝(Mytilus coruscus)稚贝附着关系。结果表明,所有测试海洋细菌形成微生物膜的最终密度随初始密度的增加而增加。所测海洋细菌均能不同程度地诱导厚壳贻贝稚贝的附着,其中Cobetia sp.3形成的微生物膜显示出最高诱导活性,其诱导的稚贝附着率为(70%±3%);Nautella sp.2、Pseudoalteromonas sp.9、Pseudoalteromonas sp.10、Bacillus sp.5和Pseudoalteromonas sp.11等5株细菌表现中等程度的诱导活性,其诱导的附着率范围为51%~60%。所有测试菌株所形成的微生物膜密度与稚贝附着均呈显著相关,尤其是Pseudoalteromonas sp.9和Cobetia sp.3诱导活性与附着率相关性极强,其相关性系数分别为0.774 1和0.723 3。系统发育分析结果表明,微生物膜密度和厚壳贻贝稚贝的附着率显著相关,然而海洋细菌诱导活性与细菌种属无关。因而,中湿度表面的海洋附着细菌对厚壳贻贝的附着有着明显的促进作用,本研究为后续开展厚壳贻贝稚贝的附着机制提供了理论依据。

Effects of bacterial biofilms formed on middle wettability surfaces on settlement of plantigrades of the mussel Mytilus coruscus

In order to obtain the useful information on the role of different bacterial strains isolated from middle wettability surface on the plantigrade settlement of the mussel Mytilus coruscus, the interaction between bacterial biofilms and plantigrade settlement was studied.The marine bacteria were isolated from the biofilms developed on the middle wettability surface and identification by 16S rDNA gene sequences was conducted.The effects of monospecific bacterial biofilms on settlement of M.coruscus plantigrades were investigated in the laboratory.The phylogenetic tree derived from the elected 16S rDNA sequence was constructed and the genetic distance was calculated.Of 6 different isolates, all bacterial biofilm showed significant inducing activity on settlement of M.coruscus plantigrades.Among the 6 bacterial species, Cobetia sp.3 biofilm induced the highest percentage of plantigrade settlement and the settlement rate was 70%±3%;Other 5 species of bacteria including Nautella sp.2, Pseudoalteromonas sp.9, Pseudoalteromonas sp.10, Bacillus sp.5 and Pseudoalteromonas sp.11 showed moderate inducing activity, and the percentages of of plantigrade settlement ranged from 51% to 60%.Bacterial density was significantly correlated with the inducing activity for each test strain.The density of monospecific bacterial biofilms increased with the initial incubation density.The inducing activity of individual bacterial isolates was not correlated with their phylogenetic relationship.Thus, marine bacteria derived from biofilms developed on moderate wettability surface can promote the settlement of plantigrades of the mussel M.coruscus. This finding is important to understand the mechanism of settlement of M.coruscus plantigrades.