Project description:Our study aimed to analyse the responses of the clonal ST131 strain, containing the ESBL and multi-drug resistance plasmid under different beta-lactam and ciprofloxacin antibiotic stress in comparison with no antibiotic stresses in order to identify the specific response of a MDR plasmid to the specific antibiotic and the potential interaction between the plasmid and the host bacteria under different stresses. The aim was to understand how the plasmid and bacterial host proteins are influenced by the different antibiotic stresses. By analysing these factors systematically we aimed to identify the pathways and core or antibiotic specific responses of the bacteria. Using proteomics we provide an unbiased protein map of a pathogen with a MDR plasmid under antibiotic stress and compare it with the same bacteria in the absence of the stress.
Project description:The dpiA and dpiB genes of Escherichia coli, which are orthologs of genes that regulate citrate uptake and utilization in Klebsiella pneumoniae, comprise a two-component signal transduction system that can modulate the replication of and destabilize the inheritance of pSC101 and certain other plasmids. Here we show that perturbed replication and inheritance result from binding of the effector protein DpiA to A+T-rich replication origin sequences that resemble those in the K. pneumoniae promoter region targeted by the DpiA ortholog, CitB. Consistent with its ability to bind to A+T-rich origin sequences, overproduction of DpiA induced the SOS response in E. coli, suggesting that chromosomal DNA replication is affected. Bacteria that overexpressed DpiA showed an increased amount of DNA per cell and increased cell size-both also characteristic of the SOS response. Concurrent overexpression of the DNA replication initiation protein, DnaA, or the DNA helicase, DnaB-both of which act at A+T-rich replication origin sequences in the E. coli chromosome and DpiA-targeted plasmids-reversed SOS induction as well as plasmid destabilization by DpiA. Our finding that physical and functional interactions between DpiA and sites of replication initiation modulate DNA replication and plasmid inheritance suggests a mechanism by which environmental stimuli transmitted by these gene products can regulate chromosomal and plasmid dynamics.
Project description:The dpiA and dpiB genes of Escherichia coli, which are orthologs of genes that regulate citrate uptake and utilization in Klebsiella pneumoniae, comprise a two-component signal transduction system that can modulate the replication of and destabilize the inheritance of pSC101 and certain other plasmids. Here we show that perturbed replication and inheritance result from binding of the effector protein DpiA to A+T-rich replication origin sequences that resemble those in the K. pneumoniae promoter region targeted by the DpiA ortholog, CitB. Consistent with its ability to bind to A+T-rich origin sequences, overproduction of DpiA induced the SOS response in E. coli, suggesting that chromosomal DNA replication is affected. Bacteria that overexpressed DpiA showed an increased amount of DNA per cell and increased cell size-both also characteristic of the SOS response. Concurrent overexpression of the DNA replication initiation protein, DnaA, or the DNA helicase, DnaB-both of which act at A+T-rich replication origin sequences in the E. coli chromosome and DpiA-targeted plasmids-reversed SOS induction as well as plasmid destabilization by DpiA. Our finding that physical and functional interactions between DpiA and sites of replication initiation modulate DNA replication and plasmid inheritance suggests a mechanism by which environmental stimuli transmitted by these gene products can regulate chromosomal and plasmid dynamics. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Keywords: Logical Set
Project description:The dpiA and dpiB genes of Escherichia coli, which are orthologs of genes that regulate citrate uptake and utilization in Klebsiella pneumoniae, comprise a two-component signal transduction system that can modulate the replication of and destabilize the inheritance of pSC101 and certain other plasmids. Here we show that perturbed replication and inheritance result from binding of the effector protein DpiA to A+T-rich replication origin sequences that resemble those in the K. pneumoniae promoter region targeted by the DpiA ortholog, CitB. Consistent with its ability to bind to A+T-rich origin sequences, overproduction of DpiA induced the SOS response in E. coli, suggesting that chromosomal DNA replication is affected. Bacteria that overexpressed DpiA showed an increased amount of DNA per cell and increased cell size-both also characteristic of the SOS response. Concurrent overexpression of the DNA replication initiation protein, DnaA, or the DNA helicase, DnaB-both of which act at A+T-rich replication origin sequences in the E. coli chromosome and DpiA-targeted plasmids-reversed SOS induction as well as plasmid destabilization by DpiA. Our finding that physical and functional interactions between DpiA and sites of replication initiation modulate DNA replication and plasmid inheritance suggests a mechanism by which environmental stimuli transmitted by these gene products can regulate chromosomal and plasmid dynamics. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Computed
Project description:Multidrug-resistant (MDR; resistance to >3 antimicrobial classes) Salmonella enterica serovar I 4,[5],12:i:- strains were linked to a 2015 foodborne outbreak from pork. Strain USDA15WA-1, associated with the outbreak, harbors an MDR module and the metal tolerance element Salmonella Genomic Island 4 (SGI-4). Characterization of SGI-4 revealed that conjugational transfer of SGI-4 resulted in the mobile genetic element (MGE) replicating as a plasmid or integrating into the chromosome. Tolerance to copper, arsenic, and antimony compounds was increased in Salmonella strains containing SGI-4 compared to strains lacking the MGE. Following Salmonella exposure to copper, RNA-seq transcriptional analysis demonstrated significant differential expression of diverse genes and pathways, including induction of numerous metal tolerance genes (copper, arsenic, silver, and mercury). Evaluation of swine administered elevated concentrations of zinc oxide (2,000 mg/kg) and copper sulfate (200 mg/kg) as an antimicrobial feed additive (Zn+Cu) in their diet for 4 weeks prior to and 3 weeks post-inoculation with serovar I 4,[5],12:i:- indicated that Salmonella shedding levels declined at a slower rate in pigs receiving in-feed Zn+Cu compared to control pigs (no Zn+Cu). The presence of metal tolerance genes in MDR Salmonella serovar I 4,[5],12:i:- may provide benefits for environmental survival or swine colonization in metal-containing settings.
Project description:In this work, a plasmid-based system is applied to inhibit the transposition of bacterial insertion sequences (IS). Using multiple guide RNAs, inactivated Cas9 was directed to simultaneously bind to the left end of IS1, IS5, IS3 and IS150 in Escherichia coli, in vivo. As a result, the transcription of IS1, and IS5 was successfully silenced, in certain cases by two orders of magnitude. The transposition rate of all four targeted elements nevertheless dropped to negligible levels, as verified at the cycA and bgl chromosomal loci. A GFP-expressing plasmid, known to be predominantly inactivated by insertion mutations also displayed a significant increase in stability. The transposition-silencing effect was easily transferable between various E. coli strains by plasmid transformation. Our portable system, or other plasmids constructed likewise can serve as useful tools to eliminate insertion mutagenesis or selectively study distinct transposable elements in numerous prokaryotic species.