Sunday, August 1, 2010
Pacific Concourse (Hyatt Regency San Francisco)
The stability of fishery resources in their natural habitat, its conservation and marketing in controlled conditions deeply depends on the knowledge and control of the microbial community with which the resource interacts. Molecular fingerprinting techniques have been envisaged as useful methods to shed light on bacterial diversity in a given ecosystem or in complex samples and for studying interaction among microbes and other organisms. In cephalopods, like octopus, there is an absolute lack of information on this relevant issue. In the present work results obtained from studies on the total bacterial community and the metabolically active fraction associated to octopus are reported. Metagenomic DNA and RNA isolated from ectopic florae of octopus were amplified with universal primers targeting hypervariable regions of the 16S rRNA. The Shannon-Weaver, Simpson and homogeneity indexes were calculated from the abundance and relative intensities of separate bands in DGGE gels. Phylotypes representing bacterial community were evenly distributed within each sample, but irregular distribution among octopus sampled in different locations was observed. Phylogenetic analysis of sequences obtained from recovered bands from DGGE gels showed that predominant bacteria were classified as Proteobacteria, specifically to genera Psychrobacter, Pseudomonas, Pseudoalteromonas, Shewanella, Vibrio, Photobacterium, Klebsiella and to Halomonadaceae family. Besides, the presence of species belonging to other genera like Bizionia (Fusobacterium) and Flavobacterium (Bacteroidetes) was also observed. Sequences belonging to the phylum Firmicutes were recovered too and grouped in a clado with members of the genera Bacillus, Carnobacterium and Lactococcus.
Keywords: Octopus sp, bacterial community, metabolically active, phylotypes, DGGE