Diversity Of The Epibiotic Microbes With The SMAR Hydrothermal Shrimp Rimicaris Sp

The discovery of hydrothermal vents and the unique, often endemic,fauna that inhabit themrepresents one of the most extraordinary,scientific discoveries of the latter twentiethcentury.Nawadays about three hundred thousand kinds of marine organisms have beenrecognized. Marine bacteria act very important roles.Shrimp of Peracarida are dominant speciesin south Mid-Atlantic Ridge, This shrimp has an enlarged gill chamber, harboring a denseectosymbiotic community of chemoautotrophic bacteria associated with mineral oxide deposits.Sample of this study is collected from the South Atlantic mid-ocean ridge hydrothermal area,preliminary estimate it belongs to the Rimicaris genus.In this paper, we use the unculture and culture methods to analysis diversity of the shrimp’ssymbiotic bacteria. In this study, an approach using16S rRNA clone libraries was used.Molecular results indicated a wider diversity than previously described for this shrimp’sepibiotic community. The result of16S rRNA gene clone library of gills from shrimp1thatclones were clustered into three groups, Proteobacteria was the dominant group, compared tototal bacterial clones, could reach96.9%, which were mainly distributed in4subgroups: ε-(82.9%),γ-(9.6%), α-(2.2%) andδ-(1.1) proteobacteria. The other bacterial groups wereBacteroidetes (1.1%) and about1%unclassified bacteria. The result of16S rRNA gene clonelibrary of gills from shrimp2was similar to the result of gills from shrimp1, there were threegroups, Proteobacteria still was the dominant group, compared to total bacterial clones, couldreach95.6%, which were mainly distributed in4subgroups: ε-(68.5%),γ-(20.1%), α-(5.6%)and ζ-(1.1%) proteobacteria. Another bacterial group were Bacteroidetes (3.4%) and about1%unclassified bacteria. The result of16S rRNA gene clone library of gills from shrimp2wassimilar to the result of gills from shrimp1, and Community structure was moresimilar.Compared the16S rRNA gene clone of gut, the clones of shrimp1could be clusteredinto three groups, Proteobacteria (67.0%), Deferribacteres (27.4%) and Bacteroidetes (11.5%),Proteobacteria were mainly distributed in3subgroups: ε-(60.2%),γ-(4.6%) and α-(7.6%)proteobacteria. The clones of shrimp2could be clustered into four groups, Proteobacteria(9.7%),Deferribacteres (61.3%), Bacteroidetes (8.6%) and Firmicutes (12.9%). Deferribacteres instead of Proteobacteria became the dominant group. We only successful constructed16SrRNA gene clone library of muscle from shrimp1, that clones were clustered into four groups,Proteobacteria was still the dominant group, compared to total bacterial clones, could reach86.5%, which were mainly distributed in3subgroups: ε-(5.4%),γ-(78.4%) andδ-(2.7%)proteobacteria. The other bacterial groups were Bacteroidetes (2.70%), Deferribacteres(8.1%)and Tenericutes about2.70%.Additionally we obtained14aerobic bacterial strains and stable anaerobic enriched cultures.The phylogenetic analysis of16S rDNA of aerobic bacteria showed that the14isolatesbelonged to Idiomarina、Marinobacter、Nesterenkonia、 Erythrobacter、Halomonas、Alteromonas、Psychrobacter、Mesonia,9strains belongs to Proteobacteria, mainly distributed in2subgroups：α-Proteobacteria (account for14.3%), γ-Proteobacteria (account for50%). Thestrains in the anaerobic enriched cultures were mainly Alcaligenes, which were γ-Proteobacteria. They may associate with nitrate reduction. One clone, identified asStenotrophomonas belonging to β-Proteobacteria, which is the potential conditional pathogenicbacterium of shrimp.