Project description:The study aimed to characterize plasmids mediating carbepenem resistance in Klebsiella pneumoniae in Pretoria, South Africa. We analysed 56 K. pneumoniae isolates collected from academic hospital around Pretoria. Based on phenotypic and molecular results of these isolates, 6 representative isolates were chosen for further analysis using long reads sequencing platform. We observed multidrug resistant phenotype in all these isolates, including resistance to aminoglycosides, tetracycline, phenicol, fosfomycin, floroquinolones, and beta-lactams antibiotics. The blaOXA-48/181 and blaNDM-1/7 were manily the plasmid-mediated carbapenemases responsible for carbapenem resistance in the K. pneumoniae isolates in these academic hospitals. These carbapenemase genes were mainly associated with plasmid replicon groups IncF, IncL/M, IncA/C, and IncX3. This study showed plasmid-mediated carbapenemase spread of blaOXA and blaNDM genes mediated by conjugative plasmids in Pretoria hospitals.
Project description:Genetic surrounding of blaNDM-1, blaNDM-3 and blaNDM-6 and conjugation frequency of blaNDM-1-carrying plasmids in Enterobacteriaceae
Project description:Enterotoxin-producing C. perfringens type A is a common cause of food poisonings. The cpe encoding the enterotoxin can be chromosomal (genotype IS1470) or plasmid-borne (genotypes IS1470-like-cpe or IS1151-cpe). The chromosomal cpe-carrying C. perfringens are a more common cause of food poisonings than plasmid-borne cpe-genotypes. The chromosomal cpe-carrying C. perfringens type A strains are generally more resistant to most food-processing conditions than plasmid-borne cpe-carrying strains. On the other hand, the plasmid-borne cpe-positive genotypes are more commonly found in human feces than chromosomal cpe-positive genotypes, and humans seem to be a reservoir for plasmid-borne cpe-carrying strains. Thus, it is possible that the epidemiology of C. perfringes type A food poisonings caused by plasmid-borne and chromosomal cpe-carrying strains is different. A DNA microarray was designed for analysis of genetic relatedness between the different cpe-positive and cpe-negative genotypes of C. perfringens strains isolated from human, animal, environmental and food samples. The DNA microarray contained two probes for all protein-coding sequences in the three genome-sequenced strains (C. perfringens type A strains 13, ATCC13124, and SM101). The chromosomal and plasmid-borne C. perfringens genotypes were grouped into two distinct clusters, one consisting of the chromosomal cpe-genotypes and the other consisting of plasmid-borne cpe-genotypes. Analysis of the variable gene pool complemented with the growth studies demonstrate different carbohydrate and amine metabolism in the chromosomal and plasmid-borne cpe-carrying strains, suggesting different epidemiology of the cpe-positive C. perfringens strain groups.
Project description:Proteome of the wild type (WT) of S. melonis TY and snc137 deleted cells carrying either a plasmid overexpressing SNC137 (Δsnc137 comp.), or an empty control vector (Δsnc137)
Project description:PdeL is a transcription regulator and c-di-GMP specific phosphodiesterase in Escherichia coli. To address the transcription regulator function of PdeL we analyzed the transcriptomes of four E. coli K12 strains during the exponential growth phase by RNA-sequencing. These four strains included (1) wild-type E. coli K12 strain BW30270 carrying an empty vector control plasmid, (2) an isogenic pdeL deletion mutant carrying the control plasmid, as well as the pdeL mutant that was complemented with (3) a plasmid carrying pdeL under control of the IPTG-inducible tac promoter or (4) a plasmid encoding a fusion protein of the PdeL’s DNA-binding domain and the C-terminal dimerization domain of phage Lambda cI repressor (PdeL-DBD_cI-C). Expression of plasmid-encoded pdeL and pdeL-DBD_cI-C, respectively, was induced by addition of IPTG for 15 minutes prior to RNA isolation. Analyses of the RNA-seq data revealed that plasmid-provided PdeL (and PdeL-DBD_cI-C) repress transcription of class II flagellar genes and presumably regulate the transcription of additional loci, while only little differences were observed between the transcriptomes of wild-type strain BW30270 and its isogenic pdeL mutant.
Project description:Transcriptome of the wild type (WT) of S. melonis TY and snc137 deleted cells carrying either a plasmid overexpressing SNC137 (Δsnc137 comp.), or an empty control vector (Δsnc137)
Project description:Chromosomes and plasmids are two forms of genetic carriers. Exogenous yeast artificial chromosomes are also considered as yeast centromeric plasmids in many cases. Here, we used state-of-the-art sequencing technologies to comprehensively profile the genetic, epigenetic, transcriptional and proteomic characteristics of an exogenous data-carrying chromosome. We found that the data-carrying DNA formed active chromatin with high chromatin accessibility and H3K4 tri-methylation levels. We also confirmed that the data-carrying chromosome had a circular shape in the nucleus and was arranged in the Rabl configuration, which may contribute to the self-replication and haploidy of the chromosome in vivo. The data-carrying chromosome displayed highly pervasive transcriptional ability and transcribed hundreds of non-coding RNAs. In summary, this work explores the chromatin epigenetic state, chromatin structure and transcriptional landscape of an exogenous artificial chromosome. The results demonstrated that the exogenous artificial chromosome did form a chromatin structure and was not a naked and incompact plasmid, which strengthen our understanding of artificial chromosomes.