RESUMO
The genomes of four strains (MB11, MB14, MB30, and MB66) of the species Corynebacterium pseudotuberculosis biovar equi were sequenced on the Ion Torrent PGM platform, completely assembled, and their gene content and structure were analyzed. The strains were isolated from horses with distinct signs of infection, including ulcerative lymphangitis, external abscesses on the chest, or internal abscesses on the liver, kidneys, and lungs. The average size of the genomes was 2.3 Mbp, with 2169 (Strain MB11) to 2235 (Strain MB14) predicted coding sequences (CDSs). An optical map of the MB11 strain generated using the KpnI restriction enzyme showed that the approach used to assemble the genome was satisfactory, producing good alignment between the sequence observed in vitro and that obtained in silico. In the resulting Neighbor-Joining dendrogram, the C. pseudotuberculosis strains sequenced in this study were clustered into a single clade supported by a high bootstrap value. The structural analysis showed that the genomes of the MB11 and MB14 strains were very similar, while the MB30 and MB66 strains had several inverted regions. The observed genomic characteristics were similar to those described for other strains of the same species, despite the number of inversions found. These genomes will serve as a basis for determining the relationship between the genotype of the pathogen and the type of infection that it causes.
RESUMO
BACKGROUND: FapR protein from the psychrotrophic species Exiguobacterium antarcticum B7 was expressed and purified, and subsequently evaluated for its capacity to bind to the promoter regions of the fabH1-fabF and fapR-plsX-fabD-fabG operons, using electrophoretic mobility shift assay. The genes that compose these operons encode for enzymes involved in the de novo synthesis of fatty acids molecules. In Bacillus subtilis, FapR regulates the expression of these operons, and consequently has influence in the synthesis of long or short-chain fatty acids. To analyze the bacterial cold adaptation, this is an important metabolic pathway because psychrotrophic microrganisms tend to synthesize short and branched-chain unsaturated fatty acids at cold to maintain cell membrane fluidity. RESULTS: In this work, it was observed that recombinant protein was able to bind to the promoter of the fully amplified fabH1-fabF and fapR-plsX-fabD-fabG operons. However, FapR was unable to bind to the promoter of fapR-plsX-fabD-fabG operon when synthesized only up to the protein-binding palindrome 5'-TTAGTACCAGATACTAA-3', thus showing the importance of the entire promoter sequence for the correct protein-DNA interaction. CONCLUSIONS: Through this observation, we demonstrate that the FapR protein possibly regulates the same operons as described for other species, which emphasizes its importance to cold adaptation process of E. antarcticum B7, a psychrotrophic bacterium isolated at Antarctica.