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.
Project description:Background: Liver cancer is the third deadliest type of cancer, posing a serious threat to human health. Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer. C. sinensis, classified as a definite group I carcinogen by the IARC (International Agency for Research on Cancer), is an important risk factor for HCC. Although many studies have shown that C. sinensis infection affects the prognosis of HCC patients, the specific mechanisms are still unclear, especially the dynamics and regulatory roles of chromatin accessibility. Results: In this study, we integrated ATAC-seq, RNA-seq, and ChIP-seq data to elucidate changes in the epigenetics of HCC after the C. sinensis infection. Many different accessibility regions (DARs) were identified both in tumors and adjacent tissue after the C. sinensis infection. Meanwhile, top TFs whose motifs were enriched in DAR were found, such as HNF4a, FOXI1, etc. Although there were slight deviations, epigenetic changes were found to be consistent with gene expression levels. We also revealed that H3K9ac, H3K4me2, H3K4me3, H3K27ac, and H3K4me1 were associated with chromatin accessibility. Importantly, we also found potential evidence that C. sinensis infection would alter the spatial structure of the HCC genome. Finally, both molecular experimental results and clinical data certified that C. sinensis infection would promote the metastasis of HCC. Conclusions: C. sinensis infection will remodel the chromatin accessibility of HCC, leading to changes in gene expression levels. This study provides conclusive evidence that C. sinensis infection alters the epigenetics of HCC.
