Project description:Transcriptional profiling of RNA-seq data from two Burkholderia species grown under conditions mimicking the cystic fibrosis lung and the soil environment
Project description:Burkholderia vietnamiensis strain G4, representative of a species routinely encountered as a contaminant of industrial product, was exposed to a proprietary preservative agent for 24 hours and gene expression analysed by RNA-seq.
Project description:Burkholderia thailandensis is closely related to highly pathogenic Burkholderia species, and it is an excellent surrogate as it rarely causes disease in humans. Understanding the complex molecular mechanisms that characterize the transition of B. thailandensis from exponential to stationary phases is critical to understanding bacterial responses to stress or nutrient limitation. We present here an integrated transcriptomic and proteomic analysis to profile gene and protein expression changes during entry into stationary phase. We identified 928 differentially expressed genes (DEGs) and 832 differentially expressed proteins (DEPs), highlighting significant transcriptional and translational reprogramming. Genes encoding proteins involved in benzoate degradation and O-antigen nucleotide sugar biosynthesis were among the most highly upregulated in stationary phase, whereas processes such as nitrogen metabolism, translation, and flagellar biosynthesis were downregulated. At the proteome level, proteins related to fatty acid degradation and butanoate metabolism accumulated along with proteins involved in synthesis of secondary metabolites. Markedly downregulated proteins included ribosomal proteins and translation factors as well as the house-keeping iron-sulfur biogenesis proteins. A protein-protein interaction (PPI) network analysis identified clusters involved in processes such as fatty acid metabolism and amino acid degradation. Surprisingly, the RpoS sigma factor, which has been shown to accumulate in stationary phase in several bacterial species, was not significantly increased in B. thailandensis during stationary phase. These findings offer comprehensive insights into B. thailandensis adaptive strategies and provide a foundation for developing interventions against pathogenic Burkholderia species.
Project description:An important, but rarely performed, test of Koch’s molecular postulates involves evaluating the capacity of candidate virulence genes to confer pathogenicity in otherwise non-virulent species. Unbiased genomic surveys of avirulent natural isolates might reveal rare variants possessing specific virulence features, which might prove useful in testing their functional sufficiency. Using a custom pan-genome array, we analyzed a panel of avirulent Burkholderia thailandensis (Bt) isolates related to Burkholderia pseudomallei (Bp), the causative agent of the often fatal human and animal disease melioidosis. We report the discovery of variant Bt isolates exhibiting isolated acquisition of a capsular polysaccharide biosynthesis gene cluster (BpCPS), long regarded as an critical species-specific virulence factor essential for Bp mammalian virulence. BpCPS-expressing Bt strains exhibited certain pathogen-related phenotypes including resistance to human complement binding, but did not exhibit enhanced virulence when assessed in two different in vivo animal infection models. Phylogenetic analysis revealed that the BpCPS-expressing Bt strains likely reside within an evolutionary subgroup distinct from the majority of previously-described Bt strains. Our findings suggest that BpCPS acquisition alone is unlikely to fully explain the ability of Bp to colonize humans and animals, highlighting the importance of other collaborating factors in the pathogenesis of mammalian melioidosis.
