Project description:Background: Pantoea ananatis LMG 2665T synthesizes and utilizes acyl homoserine lactones (AHLs) for signaling. In this strain, short chain AHLs (C4 to C8) are produced by the EanI/R quorum sensing (QS) system that is involved in pathogenicity and biofilm formation. The complete set of genes regulated by the EanI/R system in P. ananatis LMG 2665T is still not fully known. In the present study, RNA-seq was used to analyze the transcriptome profiles controlled by the EanI/R system in this strain by comparing the wild type strain and its QS mutant 2665T ean∆I/R during lag and log stages. The RNA seq data was validated by RT qPCR. Results: The results showed that the EanI/R regulon in P. ananatis LMG 2665T comprised 144 genes, constituting 3.3% of the whole transcriptome under the experimental conditions in this study. The majority of genes regulated by the EanI/R system included genes for flagella assembly, bacterial chemotaxis, pyruvate metabolism, two component system, metabolic pathways, microbial metabolism and biosynthesis of secondary metabolites. Conclusions: This is the first study to identify the EanI/R QS regulon in P. ananatis LMG 2665T. Functional analysis of genes regulated the EanI/R system in LMG 2665T could help unveil genes that play a vital role in pathogenesis and survival strategies of this pathogen.
Project description:Background: The human pathogen Arcobacter butzleri is a member of the epsilon subdivision of the Proteobacteria and a close taxonomic relative of other established pathogens, such as Campylobacter jejuni and Helicobacter pylori. Here we present the complete genome sequence of the human clinical isolate, A. butzleri strain RM4018. Results: Arcobacter butzleri is a member of the Campylobacteraceae, but the majority of its proteome is most similar to those of Thiomicrospira denitrificans and Wolinella succinogenes, both members of the Helicobacteraceae. In addition, many of the genes and pathways described here, e.g. those involved in signal transduction and sulfur metabolism, have been identified previously within the epsilon subdivision only in T. denitrificans and/or W. succinogenes, or are unique to the subdivision. The analyses indicated also that a large proportion of the A. butzleri genome is devoted to growth and survival under diverse environmental conditions, with a large number of respiration-associated proteins, signal transduction and chemotaxis proteins and proteins involved in DNA repair and adaptation. To investigate the genomic diversity of A. butzleri strains, we constructed an A. butzleri DNA microarray comprising 2238 genes from strain RM4018. Comparative genomic indexing analysis of 12 additional A. butzleri strains identified both the core genes of A. butzleri and intraspecies hypervariable regions, where < 70% of the genes were present in at least two strains. Conclusion: The presence of environmentally-associated pathways and loci, as well as genes associated with virulence indicates that this free-living, water-borne organism A. butzleri can be classified rightfully as an emerging pathogen. Keywords: comparative genomic hybridization