scholarly journals CpxR regulates the colistin susceptibility of Salmonella Typhimurium by a multitarget mechanism

2020 ◽  
Vol 75 (10) ◽  
pp. 2780-2786 ◽  
Author(s):  
Ya-Jun Zhai ◽  
Hua-Run Sun ◽  
Xing-Wei Luo ◽  
Jian-Hua Liu ◽  
Yu-Shan Pan ◽  
...  
Keyword(s):  
Salmonella Typhimurium ◽  
Target Genes ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Efflux Pump ◽  
Colistin Resistance ◽  
Mobility Shift ◽  
Serovar Typhimurium ◽  
Electrophoretic Mobility Shift Assays ◽  
First Time ◽  
Signalling Systems

Abstract Background The two-component signalling systems PmrAB and PhoPQ of Salmonella have been extensively studied with regard to colistin resistance. We previously showed that overexpressed CpxR could significantly increase the colistin susceptibility (16-fold compared with the WT strain) of Salmonella enterica serovar Typhimurium (Salmonella Typhimurium) through PmrAB and PhoPQ. Objectives To identify the potential target genes of CpxR in PmrAB- and PhoPQ-related signalling pathways. Methods His6-CpxR was prokaryotically expressed and purified by Ni-NTA resin affinity chromatography. β-Galactosidase activity assays were conducted to investigate whether CpxR could regulate the promoters of colistin resistance-related genes (CRRGs). Electrophoretic mobility shift assays (EMSAs) were used to further detect His6-CpxR complexes with promoters of CRRGs. Results We demonstrated for the first time (to the best of our knowledge) that CpxR and the AcrAB–TolC efflux pump have reciprocal effects on CRRG transcription. Additionally, CpxR could regulate the colistin susceptibility of Salmonella Typhimurium by binding directly to the promoters of phoPQ, pmrC, pmrH and pmrD at the CpxR box-like sequences or indirectly through other regulators including pmrAB and mgrB. Conclusions CpxR could regulate the colistin susceptibility of Salmonella Typhimurium by a multitarget mechanism.

SoxS regulates the expression of the Salmonella enterica serovar Typhimurium ompW gene

Microbiology ◽  
2009 ◽  
Vol 155 (8) ◽  
pp. 2490-2497 ◽  
Author(s):  
F. Gil ◽  
I. Hernández-Lucas ◽  
R. Polanco ◽  
N. Pacheco ◽  
B. Collao ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Regulatory Region ◽  
Transcription Start ◽  
Mobility Shift ◽  
Serovar Typhimurium ◽  
A Minor ◽  
Electrophoretic Mobility Shift Assays ◽  
Putative Binding Site ◽  
Transcriptional Fusions

OmpW of Salmonella enterica serovar Typhimurium has been described as a minor porin involved in osmoregulation, and is also affected by environmental conditions. Biochemical and genetic evidence from our laboratory indicates that OmpW is involved in efflux of and resistance towards paraquat (PQ), and its expression has been shown to be activated in response to oxidative stress. In this study we have explored ompW expression in response to PQ. Primer extension and transcriptional fusions showed that its expression was induced in the presence of PQ. In silico analyses suggested a putative binding site for the SoxS transcriptional factor at the ompW regulatory region. Electrophoretic mobility shift assays (EMSAs) and footprinting experiments showed that SoxS binds at a region that starts close to −54 and ends at about −197 upstream of the transcription start site. Transcriptional fusions support the relevance of this region in ompW activation. The SoxS site is in the forward orientation and its location suggests that the ompW gene has a class I SoxS-dependent promoter.

Detection of Virulence Plasmid–Encoded Genes in Salmonella Typhimurium and Salmonella Kentucky Isolates Recovered from Commercially Processed Chicken Carcasses

2019 ◽  
Vol 82 (8) ◽  
pp. 1364-1368 ◽  
Author(s):  
RIZWANA TASMIN ◽  
PAUL A. GULIG ◽  
SALINA PARVEEN
Keyword(s):  
United States ◽  
Salmonella Typhimurium ◽  
Virulence Genes ◽  
Salmonella Enterica Serovar Typhimurium ◽  
The United States ◽  
Clinical Isolates ◽  
Virulence Plasmid ◽  
Chicken Carcass ◽  
Serovar Typhimurium ◽  
Salmonella Virulence

ABSTRACT Salmonella enterica serovar Typhimurium is one of the leading causes of nontyphoidal gastroenteritis of humans in the United States. Commercially processed poultry carcasses are frequently contaminated with Salmonella serovar Kentucky in the United States. The aim of the study was to detect the Salmonella virulence plasmid containing the spv genes from Salmonella isolates recovered from commercially processed chicken carcasses. A total of 144 Salmonella isolates (Salmonella Typhimurium, n = 72 and Salmonella Kentucky, n = 72) were used for isolation of plasmids and detection of corresponding virulence genes (spvA, spvB, and spvC). Only four (5.5%) Salmonella Typhimurium isolates tested positive for all three virulence genes and hence were classified as possessing the virulence plasmid. All isolates of Salmonella Kentucky were negative for the virulence plasmid and genes. These results indicate that the virulence plasmid, which is very common among clinical isolates of Typhimurium and other Salmonella serovars (e.g., Enteritidis, Dublin, Choleraesuis, Gallinarum, Pullorum, and Abortusovis), may not be present in a significant portion of commercially processed chicken carcass isolates.

Identification of Salmonella enterica Serovar Typhimurium Using Specific PCR Primers Obtained by Comparative Genomics in Salmonella Serovars

2006 ◽  
Vol 69 (7) ◽  
pp. 1653-1661 ◽  
Author(s):  
H. J. KIM ◽  
S. H. PARK ◽  
T. H. LEE ◽  
B. H. NAHM ◽  
Y. H. CHUNG ◽  
...  
Keyword(s):  
Comparative Genomics ◽  
Salmonella Enterica ◽  
Target Genes ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Foodborne Pathogen ◽  
Pcr Primers ◽  
Genomic Sequences ◽  
Local Alignment ◽  
Serovar Typhimurium ◽  
Salmonella Serovars

Salmonella enterica serovar Typhimurium is a major foodborne pathogen throughout the world. Until now, the specific target genes for the detection and identification of serovar Typhimurium have not been developed. To determine the specific probes for serovar Typhimurium, the genes of serovar Typhimurium LT2 that were expected to be unique were selected with the BLAST (Basic Local Alignment Search Tool) program within GenBank. The selected genes were compared with 11 genomic sequences of various Salmonella serovars by BLAST. Of these selected genes, 10 were expected to be specific to serovar Typhimurium and were not related to virulence factor genes of Salmonella pathogenicity island or to genes of the O and H antigens of Salmonella. Primers for the 10 selected genes were constructed, and PCRs were evaluated with various genomic DNAs of Salmonella and non-Salmonella strains for the specific identification of Salmonella serovar Typhimurium. Among all the primer sets for the 10 genes, STM4497 showed the highest degree of specificity to serovar Typhimurium. In this study, a specific primer set for Salmonella serovar Typhimurium was developed on the basis of the comparison of genomic sequences between Salmonella serovars and was validated with PCR. This method of comparative genomics to select target genes or sequences can be applied to the specific detection of microorganisms.

scholarly journals Presence of atrs-Like Motif Promotes Rep-Mediated Wild-Type Adeno-Associated Virus Type 2 Integration

2015 ◽  
Vol 89 (14) ◽  
pp. 7428-7432 ◽  
Author(s):  
Karl Petri ◽  
Richard Gabriel ◽  
Leticia Agundez ◽  
Raffaele Fronza ◽  
Saira Afzal ◽  
...  
Keyword(s):  
Virus Type ◽  
Integration Site ◽  
Dermal Fibroblasts ◽  
Wild Type ◽  
Mobility Shift ◽  
Adeno Associated Virus ◽  
Rep Protein ◽  
Electrophoretic Mobility Shift Assays ◽  
First Time

High-throughput integration site (IS) analysis of wild-type adeno-associated virus type 2 (wtAAV2) in human dermal fibroblasts (HDFs) and HeLa cells revealed that juxtaposition of a Rep binding site (RBS) and terminal resolution site (trs)-like motif leads to a 4-fold-increased probability of wtAAV integration. Electrophoretic mobility shift assays (EMSAs) confirmed binding of Rep to off-target RBSs. For the first time, we show Rep protein off-target nicking activity, highlighting the importance of the nicking substrate for Rep-mediated integration.

scholarly journals The RcsCDB Signaling System and Swarming Motility in Salmonella enterica Serovar Typhimurium: Dual Regulation of Flagellar and SPI-2 Virulence Genes

2007 ◽  
Vol 189 (23) ◽  
pp. 8447-8457 ◽  
Author(s):  
Qingfeng Wang ◽  
Yifang Zhao ◽  
Michael McClelland ◽  
Rasika M. Harshey
Keyword(s):  
Salmonella Enterica ◽  
Target Genes ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Acid Synthesis ◽  
Signaling System ◽  
Swarming Motility ◽  
Colanic Acid ◽  
Serovar Typhimurium ◽  
Type 3 ◽  
Regulatory Properties

ABSTRACT The Rcs phosphorelay is a multicomponent signaling system that positively regulates colanic acid synthesis and negatively regulates motility and virulence. We have exploited a spontaneously isolated mutant, IgaA(T191P), that is nearly maximally activated for the Rcs system to identify a vast set of genes that respond to the stimulation, and we report new regulatory properties of this signaling system in Salmonella enterica serovar Typhimurium. Microarray data show that the Rcs system normally functions as a positive regulator of SPI-2 and other genes important for the growth of Salmonella in macrophages, although when highly activated the system completely represses the SPI-1/SPI-2 virulence, flagellar, and fimbrial biogenesis pathways. The auxiliary protein RcsA, which works with RcsB to positively regulate colanic acid and other target genes, not only stimulates but also antagonizes the positive regulation of many genes in the igaA mutant. We show that RcsB represses motility through the RcsB box in the promoter region of the master operon flhDC and that RcsA is not required for this regulation. Curiously, RcsB selectively stimulates expression of the flagellar type 3 secretion genes fliPQR; an RcsAB box located downstream of fliR influences this regulation. We show that excess colanic acid impairs swimming and inhibits swarming motility, consistent with the inverse regulation of the two pathways by the Rcs system.

Fate of Staphylococcus aureus, Salmonella enterica Serovar Typhimurium, and Vibrio vulnificus in Raw Oysters Treated with Chitosan

2006 ◽  
Vol 69 (7) ◽  
pp. 1600-1604 ◽  
Author(s):  
PALLAVI CHHABRA ◽  
YAO-WEN HUANG ◽  
JOSEPH F. FRANK ◽  
REVIS CHMIELEWSKI ◽  
KEITH GATES
Keyword(s):  
Staphylococcus Aureus ◽  
Hydrochloric Acid ◽  
Salmonella Typhimurium ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Vibrio Vulnificus ◽  
Storage Period ◽  
Major Effect ◽  
Chitosan Concentration ◽  
Serovar Typhimurium

The fate of Staphylococcus aureus, Salmonella enterica serovar Typhimurium, and Vibrio vulnificus in oysters treated with chitosan was investigated. Three concentrations (0.5, 1.0, and 2.0%) of chitosan in 0.5% hydrochloric acid were prepared and coated onto raw oysters, which were then stored at 4°C for 12 days. Untreated oysters and oysters coated with 0.5% hydrochloric acid without chitosan were used as controls. S. aureus cells were most sensitive to 2.0% chitosan followed by 0.5 and 1.0%. In general, chitosan treatment of oysters produced a decline in the population of S. aureus by 1 to 4 log CFU/ml compared with the untreated control. Chitosan treatment had no influence on the reduction of Salmonella Typhimurium over the 12-day storage period; inhibition of Salmonella Typhimurium growth was similar in both the control samples and the chitosan-treated samples. However, time of storage had a major effect on the survival of Salmonella Typhimurium on oysters. Neither time nor chitosan concentration had a significant effect on the growth of V. vulnificus during storage. All treatments were similar in inhibiting V. vulnificus growth.

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