Effects Of Vibrio Biofilms On The Settlement Of Plantigrades Of The Mussel Mytilus Coruscus

M.coruscus is one of the main aquatic product in China,and it is also one of the main of marine fouling organisms in China.There are vast distribution areas in China's coastal areas.The thick mussel is mainly attached to the surface of the attached base(net rope,intertidal zone rock,embankment facility table,etc.).The settlement process is an extremely important life course for thick mussels.When the environmental factors are adversely changed,the mussel will cut the foot wire by itself,re-select the settlement basic and settlement again,so the study of the mussel settlement both benefit to mussels breeding industry and the mussels fouling.Previous studies have found that natural microbial biofilm are highly efficient natural inducers settlement to mussels,and marine bacteria,which are one of the important members of natural microbial biofilm,are important factors affecting the settlement of mussels.At the same time,previous studies have shown that marine bacteria have a large proportion of Vibrio,which is one of the first bacterial groups to be planted on the surface of natural biofilm.Therefore,the effects of marine microbial biofilm coating on the mussel were studied,and the metabolites of the microbial biofilm of marine Vibrio was analyzed.Mainly include the following:1.Effects of Vibrio biofilms of different sources on settlement of plantigrades of the mussel M.coruscusMarine biofilms play a crucial role in the settlement of plantigrades of the mussel M.coruscus,but the effect of Vibrio derived from different resources on the settlement of plantigrades of the mussel M.coruscus remains unknown.Ten marine Vibrio species were isolated from natural biofilms and the intestine of the wild adult mussel M.coruscus and identified to investigat the relationship between these biofilms and mussel planitigrade settlement.The results showed that Vibrio biofilm cell densities increased with the increasing initial cell density.All test Vibrio sp.biofilms can significantly promote mussel settlement attachment,and the percentage of plantigrade settlement ranged from 17% to 67%.The inducing activities of these bacterial biofilms were significantly correlated to the microbial biofilms density,and the correlation coefficient in Vibrio crassostreae ECSMB14106 was the highest(0.8992).In addition,the inducing activity of these bacterial strains was not correlated to the source of Vibrio.This study showed that marine Vibrio of the different sources induced mussel settlement and the finding is important for the understanding the potential molecular mechanism of the biofilms mediating the settlement process in this species.2.Analysis of Vibrio biofilms witch have the different effects on mussel settlementThe results showed that the highest activity was Vibrio sp.17,followed by V.crassostreae ECSMB14106,the third was Vibrio sp.13,and the lowest was Vibrio sp.19.In this study,the biological characteristics of four strains of Vibrio were studied by confocal microscopy,electron microscopy scanning technique,SDS-PAGE protein analysis and extracellular polysaccharide staining.Confocal microscopy showed that there were significant differences in the film thickness of the four bacteria-forming membranes,and the film thickness was associated with settlement ability.Scanning electron microscopy showed that the bacterial morphology of Vibrio sp.17 and V.crassostreae ECSMB14106 was short rod,and Vibrio sp.19 was elongated,and Vibrio sp.13 was petal.SDS-PAGE analysis showed that the total bacterial protein of the four strains was different,and the protein bands of Vibrio sp.17 were the largest,with 31 bands.The results showed that Vibrio sp.17 had the highest polysaccharide content.In this study,the biological characteristics of the microbial biofilm formed by the same kind of bacteria were analyzed from several angles.The relationship between biofilm thickness,protein difference and extracellular polysaccharide content was found.In order to explore the effect on mussel settlement,the main induction factor attached to the mussel settlement lay a certain foundation.