海假交替单胞菌(Pseudoalteromonas marina)鞭毛蛋白对生物被膜形成及厚壳贻贝附着的影响

Effects of Pseudoalteromonas marina flagellin on biofilm formation and settlement of Mytilus coruscus

大多数海洋无脊椎动物在发育过程中都经历浮游、底栖附着阶段,厚壳贻贝(Mytilus coruscus)作为海洋经济物种与大型污损生物,其附着机制受到广泛关注。为探究海洋细菌与厚壳贻贝附着的互作关系,选取了对厚壳贻贝稚贝附着具有较高诱导活性的海洋细菌--海假交替单胞菌(Pseudoalteromonas marina),采用酸解超速离心法提取P.marina的鞭毛蛋白。将提取的鞭毛蛋白与琼脂糖溶液混合,形成凝胶直接刺激稚贝;再用提取的鞭毛蛋白处理P.marina生物被膜进行稚贝附着实验。通过共聚焦激光扫描分析形成的生物被膜上生物量、细菌密度和胞外产物含量的变化。结果表明:P.marina鞭毛蛋白与琼脂糖形成的混合凝胶可显著促进厚壳贻贝稚贝的附着;鞭毛蛋白处理的生物被膜对厚壳贻贝稚贝附着的诱导活性显著提高;生物被膜上的生物量、细菌密度、膜厚、胞外β-多糖、脂质和蛋白浓度都有所增加。研究表明,鞭毛蛋白可以直接调控厚壳贻贝稚贝的附着,也可通过改变P.marina生物被膜的生物学特性,间接影响厚壳贻贝稚贝的附着,为探究细菌鞭毛蛋白与厚壳贻贝附着互作机制提供理论依据。

Most marine invertebrates undergo planktonic and benthic stages during growth.As a marine economic shellfish and macrofouling organism,Mytilus coruscus has attracted widespread attention.To explore the interaction between marine bacteria and the mussel settlement,Pseudoalteromonas marina,which has a high inducing activity for the plantigrade settlement of the M.coruscus was chosen and the flagellin was extracted by acid hydrolysis ultracentrifugation.The impact of extracted flagellin mixed with agarose solution to on plantigrade settlement was tested directly.The P.marina biofilms treated with extracted flagellin were used to investigate the inducing capacity on plantigrade settlement.Changes in biomass,bacterial density and extracellular products of the biofilms were analyzed by confocal laser scanning microscopy.The results showed that the mixed gel containing P.marina flagellin and agarose significantly promoted the settlement of plantigrades.In other treatment,the flagellin-treated biofilms also had a high inductivity of plantigrade settlement.Biomass,bacterial density,membrane thickness,extracellularβ-polysaccharide,lipid and protein contents all increased.The study reveals that flagellin can directly regulate the settlement of plantigrades and control the inductivity by changing the biological characteristics of the P.marina biofilm indirectly.The study is valuable for clarifying the interaction between bacterial flagellin and plantigrade settlement of the M.coruscus.