%0 Journal Article %A Moreira, David %A Rodríguez-Valera, Francisco %A López-García, Purificación %T Metagenomic analysis of mesopelagic Antarctic plankton reveals a novel deltaproteobacterial group %D 2006 %J Microbiology, %V 152 %N 2 %P 505-517 %@ 1465-2080 %R https://doi.org/10.1099/mic.0.28254-0 %K HGT, horizontal gene transfer %K MRG, myxobacteria-related group %K ITS, intergenic spacer %I Microbiology Society, %X Phylogenetic screening of 3200 clones from a metagenomic library of Antarctic mesopelagic picoplankton allowed the identification of two bacterial 16S-rDNA-containing clones belonging to the Deltaproteobacteria, DeepAnt-1F12 and DeepAnt-32C6. These clones were very divergent, forming a monophyletic cluster with the environmental sequence GR-WP33-58 that branched at the base of the myxobacteria. Except for the possession of complete rrn operons without associated tRNA genes, DeepAnt-1F12 and DeepAnt-32C6 were very different in gene content and organization. Gene density was much higher in DeepAnt-32C6, whereas nearly one-third of DeepAnt-1F12 corresponded to intergenic regions. Many of the predicted genes encoded by these metagenomic clones were informational (i.e. involved in replication, transcription, translation and related processes). Despite this, a few putative cases of horizontal gene transfer were detected, including a transposase. DeepAnt-1F12 contained one putative gene encoding a long cysteine-rich protein, probably membrane-bound and Ca2+-binding, with only eukaryotic homologues. DeepAnt-32C6 carried some predicted genes involved in metabolic pathways that suggested this organism may be anaerobic and able to ferment and to degrade complex compounds extracellularly. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.28254-0