ABSTRACT
MOTIVATION: Next-generation sequencing methods are generating increasingly massive datasets, yet still do not fully capture genetic diversity in the richest environments. To understand such complicated and elusive systems, effective tools are needed to assist with delineating the differences found in and between community datasets. RESULTS: The Small Subunit Markov Modeler (SSuMMo) was developed to probabilistically assign SSU rRNA gene fragments from any sequence dataset to recognized taxonomic clades, producing consistent, comparable cladograms. Accuracy tests predicted >90% of genera correctly for sequences downloaded from public reference databases. Sequences from a next-generation sequence dataset, sampled from lean, overweight and obese individuals, were analysed to demonstrate parallel visualization of comparable datasets. SSuMMo shows potential as a valuable curatorial tool, as numerous incorrect and outdated taxonomic entries and annotations were identified in public databases. AVAILABILITY AND IMPLEMENTATION: SSuMMo is GPLv3 open source Python software, available at http://code.google.com/p/ssummo/. Taxonomy and HMM databases can be downloaded from http://bioltfws1.york.ac.uk/ssummo/. SUPPLEMENTARY INFORMATION: Supplemental materials are available at Bioinformatics Online.
Subject(s)
Archaea/isolation & purification , Bacteria/isolation & purification , Markov Chains , Metagenomics/methods , Software , Archaea/classification , Archaea/genetics , Bacteria/classification , Bacteria/genetics , RibotypingABSTRACT
The Actinomycetales bacteria Rhodococcus opacus PD630 and Rhodococcus jostii RHA1 bioconvert a diverse range of organic substrates through lipid biosynthesis into large quantities of energy-rich triacylglycerols (TAGs). To describe the genetic basis of the Rhodococcus oleaginous metabolism, we sequenced and performed comparative analysis of the 9.27 Mb R. opacus PD630 genome. Metabolic-reconstruction assigned 2017 enzymatic reactions to the 8632 R. opacus PD630 genes we identified. Of these, 261 genes were implicated in the R. opacus PD630 TAGs cycle by metabolic reconstruction and gene family analysis. Rhodococcus synthesizes uncommon straight-chain odd-carbon fatty acids in high abundance and stores them as TAGs. We have identified these to be pentadecanoic, heptadecanoic, and cis-heptadecenoic acids. To identify bioconversion pathways, we screened R. opacus PD630, R. jostii RHA1, Ralstonia eutropha H16, and C. glutamicum 13032 for growth on 190 compounds. The results of the catabolic screen, phylogenetic analysis of the TAGs cycle enzymes, and metabolic product characterizations were integrated into a working model of prokaryotic oleaginy.
