Percorrer por autor "Eriksson, Dominic"
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- Bacterial diversity of the gorgonian coral Eunicella labiata: how much can we cultivate?Publication . Eriksson, Dominic; Serrão, Ester; Costa, RodrigoBacterial communities inhabiting non-calcified gorgonian corals (Octocorallia, Gorgoniidae) are apparently unique in taxonomic composition and may benefit their host by several means, including chemical defense and nutrient provision. However, in spite of their distinct phylogenetic diversity, the gorgonian symbiotic consortium has thus far been scarcely addressed, and thus the microbiota of several gorgonian hosts remains uncharted. This thesis describes the bacterial diversity found in the gorgonian host Eunicella labiata, determines its degree of uniqueness in comparison with the structure of the surrounding bacterioplankton and reveals the readily cultivatable fraction within this symbiotic consortium. To this end, a custom methodological approach was employed allowing direct comparison between the “total” and “cultivatable” bacterial community inhabiting E. labiata using massive Illumina sequencing of 16S rRNA gene amplicons. The 16S rRNA gene Operational Taxonomic Units (OTUs) were established at a cut-off of 97% gene similarity. Biodiversity indices such as the Shannon-Wiener were highest in the bacterial community obtained from seawater. A Tukey Honest Post Hoc test determined significant differences between biodiversity indices and sample categories. A closer look into taxonomic profiles and the relative abundances of dominant genera, clearly showed differences between microhabitats, with Candidatus Actinomarina dominating the seawater samples whereas within Ruegeria and Endozoicomonas represented the dominant fraction within E. labiata. The cultivatable community retrieved from E. labiata was close to the total community (62%) and speaks for a successful cultivation attempt of the E. labiata bacteriome. Unique OTUs within the gorgonian coral sum up to 4% in contrast to the unique fraction of OTUs found in the seawater, accounting to 31.1%. Finally, a Principle Coordinate Analysis and bootstrap values obtained from a hierarchical Cluster Analysis support the clear separation of the taxonomic community between the seawater and the gorgonian coral.
- The gorgonian coral Eunicella labiata hosts a distinct prokaryotic consortium amenable to cultivationPublication . Keller-Costa, Tina; Eriksson, Dominic; Gonçalves, Jorge Manuel Santos; Gomes, Newton C. M.; Lago-Lestón, Asunción; Costa, RodrigoMicrobial communities inhabiting gorgonian corals are believed to benefit their hosts through nutrient provision and chemical defence; yet much remains to be learned about their phylogenetic uniqueness and cultivability. Here, we determined the prokaryotic community structure and distinctiveness in the gorgonian Eunicella labiata by Illumina sequencing of 16S rRNA genes from gorgonian and seawater metagenomic DNA. Furthermore, we used a 'plate-wash' methodology to compare the phylogenetic diversity of the 'total' gorgonian bacteriome and its 'cultivatable' fraction. With 1016 operational taxonomic units (OTUs), prokaryotic richness was higher in seawater than in E. labiata where 603 OTUs were detected, 68 of which were host-specific. Oceanospirillales and Rhodobacterales predominated in the E. labiata communities. One Oceanospirillales OTU, classified as Endozoicomonas, was particularly dominant, and closest relatives comprised exclusively uncultured clones from other gorgonians. We cultivated a remarkable 62% of the bacterial symbionts inhabiting E. labiata: Ruegeria, Sphingorhabdus, Labrenzia, other unclassified Rhodobacteraceae, Vibrio and Shewanella ranked among the 10 most abundant genera in both the cultivation-independent and dependent samples. In conclusion, the E. labiata microbiome is diverse, distinct from seawater and enriched in (gorgonian)-specific bacterial phylotypes. In contrast to current understanding, many dominant E. labiata symbionts can, indeed, be cultivated.