Friday, October 28, 2011
Hall 1-2 (San Jose Convention Center)
The uncultured Bacteria candidate division SR1 (Sulfur-River 1) has been reported in diverse environments including lakes, rivers, springs, humans and termites, but is still poorly characterized, with only 365 16S rDNA sequences found in online databases. We applied culture-independent molecular techniques to determine the SR1 diversity in samples from three environmental sites (microbial mat, sludge and sulfur springs) and one host organism (termite gut). First we PCR amplified 16S rDNA genes from each of those samples using SR1-specific primers, some of which were designed in our lab. Then, PCR products were cloned, sequenced and analyzed using bioinformatics. Out of 680 clones sequenced, we identified 34 unique SR1 phylotypes using Operational Taxonomic Unit (OTU)-prediction software. Those 34 sequences fell into 8 of the 9 currently published SR1 subgroups (not including the BH1 subgroup). Our results were also supported by a phylogenetic tree built in ARB software. We propose 3 new phylogenetic subgroups for the SR1 division for a new total of 11 SR1 subgroups.