Project description:Campylobacter jejuni is the leading cause of campylobacteriosis in the developed world. Although most cases are caused by consumption of contaminated meat, a significant proportion is caused by consumption of contaminated water. Some C. jejuni isolates are better than others at surviving in water, which suggests that these strains are better adapted to transmission by water than others. The aim of this study is to investigate this phenomenon further. CFU counts and viability assays showed that strain 81116 survives better than strain 81-176 in a defined freshwater medium at 4°C. Comparative transcriptomic profiling using microarray revealed that these strains respond differently to water. This series presents the transcriptome of strain 81-176 in water.
Project description:Paenibacillus polymyxa is a root-associated plant growth-promoting rhizobacterium. It was reported that many strains of P. polymyxa naturally exhibited the phenotypic variation. In the phase variation, the characteristics of the wild-type ‘B’ and the variant ‘F’ are very different in sporulation formation, motility, antibiotic ability and so on. For better understanding of the actual physiological changes, we performed RNA-seq analyses of P. polymyxa E681 to compare genome wide patterns of gene expression. As a result, we obtained 1,062 differentially expressed genes related to flagellar assembly and transport systems.
Project description:Paenibacillus polymyxa is an agriculturally important plant growth promoting rhizobacterium (PGPR). Many Paenibacillus species are known to be engaged in complex bacteria-bacteria and bacteria-host interactions, which in other bacteria were shown to necessitate quorum sensing communication, but to date no quorum sensing systems have been described in Paenibacillus. Here we show that the type strain P. polymyxa ATCC 842 encodes at least 16 peptide-based communication systems. Each of these systems comprises a pro-peptide that is secreted to the growth medium and further processed to generate a mature short peptide. Each peptide has a cognate intracellular receptor of the RRNPP family, and we show that external addition of P. polymyxa communication peptides to the medium leads to reprogramming of the transcriptional response. We found that these quorum sensing systems are conserved across hundreds of species belonging to the Paenibacillaceae family, with some species encoding more than 25 different peptide-receptor pairs, representing a record number of quorum sensing systems encoded in a single genome.
