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Transcriptional Regulation of opaR, qrr2–4 and aphA by the Master Quorum-Sensing Regulator OpaR in Vibrio parahaemolyticus

Background Vibrio parahaemolyticus is a leading cause of infectious diarrhea and enterogastritis via the fecal-oral route. V. harveyi is a pathogen of fishes and invertebrates, and has been used as a model for quorum sensing (QS) studies. LuxR is the master QS regulator (MQSR) of V. harveyi, and LuxR-dependent expression of its own gene, qrr2–4 and aphA have been established in V...

Identification of Novel Protein-Protein Interactions of Yersinia pestis Type III Secretion System by Yeast Two Hybrid System

Type III secretion system (T3SS) of the plague bacterium Y. pestis encodes a syringe-like structure consisting of more than 20 proteins, which can inject virulence effectors into host cells to modulate the cellular functions. Here in this report, interactions among the possible components in T3SS of Yersinia pestis were identified using yeast mating technique. A total of 57 genes...

Fur Is a Repressor of Biofilm Formation in Yersinia pestis

Background Yersinia pestis synthesizes the attached biofilms in the flea proventriculus, which is important for the transmission of this pathogen by fleas. The hmsHFRS operons is responsible for the synthesis of exopolysaccharide (the major component of biofilm matrix), which is activated by the signaling molecule 3′, 5′-cyclic diguanylic acid (c-di-GMP) synthesized by the only...

Molecular Characterization of Direct Target Genes and cis-Acting Consensus Recognized by Quorum-Sensing Regulator AphA in Vibrio parahaemolyticus

Background AphA is the master quorum-sensing (QS) regulator operating at low cell density in vibrios. Molecular regulation of target genes by AphA has been characterized in Vibrio harveyi and V. cholerae, but it is still poorly understood in V. parahaemolyticus. Methodology/Principal Findings The AphA proteins are extremely conserved in V. parahaemolyticus, Vibrio sp. Ex25...

Molecular Characterization of Transcriptional Regulation of rovA by PhoP and RovA in Yersinia pestis

Background Yersinia pestis is the causative agent of plague. The two transcriptional regulators, PhoP and RovA, are required for the virulence of Y. pestis through the regulation of various virulence-associated loci. They are the global regulators controlling two distinct large complexes of cellular pathways. Methodology/Principal Findings Based on the LacZ fusion, primer...

Features of Variable Number of Tandem Repeats in Yersinia pestis and the Development of a Hierarchical Genotyping Scheme

Background Variable number of tandem repeats (VNTRs) that are widely distributed in the genome of Yersinia pestis proved to be useful markers for the genotyping and source-tracing of this notorious pathogen. In this study, we probed into the features of VNTRs in the Y. pestis genome and developed a simple hierarchical genotyping system based on optimized VNTR loci. Methodology...

Ambient Stable Quantitative PCR Reagents for the Detection of Yersinia pestis

Background Although assays for detecting Yersinia pestis using TaqMan probe-based real-time PCR have been developed for years, little is reported on room-temperature-stable PCR reagents, which will be invaluable for field epidemic surveillance, immediate response to public health emergencies, counter-bioterrorism investigation, etc. In this work, a set of real-time PCR reagents...

Two-Step Source Tracing Strategy of Yersinia pestis and Its Historical Epidemiology in a Specific Region

Source tracing of pathogens is critical for the control and prevention of infectious diseases. Genome sequencing by high throughput technologies is currently feasible and popular, leading to the burst of deciphered bacterial genome sequences. Utilizing the flooding genomic data for source tracing of pathogens in outbreaks is promising, and challenging as well. Here, we employed...

Regulatory effects of cAMP receptor protein (CRP) on porin genes and its own gene in Yersinia pestis

Background The cAMP receptor protein (CRP) is a global bacterial regulator that controls many target genes. The CRP-cAMP complex regulates the ompR-envZ operon in E. coli directly, involving both positive and negative regulations of multiple target promoters; further, it controls the production of porins indirectly through its direct action on ompR-envZ. Auto-regulation of CRP...

Phenotypic and transcriptional analysis of the osmotic regulator OmpR in Yersinia pestis

Background The osmotic regulator OmpR in Escherichia coli regulates differentially the expression of major porin proteins OmpF and OmpC. In Yersinia enterocolitica and Y. pseudotuberculosis, OmpR is required for both virulence and survival within macrophages. However, the phenotypic and regulatory roles of OmpR in Y. pestis are not yet fully understood. Results Y. pestis OmpR is...

Direct and negative regulation of the sycO-ypkA-ypoJ operon by cyclic AMP receptor protein (CRP) in Yersinia pestis

Background Pathogenic yersiniae, including Y. pestis, share a type III secretion system (T3SS) that is composed of a secretion machinery, a set of translocation proteins, a control system, and six Yop effector proteins including YpkA and YopJ. The cyclic AMP receptor protein (CRP), a global regulator, was recently found to regulate the laterally acquired genes (pla and pst) in Y...

Cell Membrane Is Impaired, Accompanied by Enhanced Type III Secretion System Expression in Yersinia pestis Deficient in RovA Regulator

Background In the enteropathogenic Yersinia species, RovA regulates the expression of invasin, which is important for enteropathogenic pathogenesis but is inactivated in Yersinia pestis. Investigation of the RovA regulon in Y. pestis at 26°C has revealed that RovA is a global regulator that contributes to virulence in part by the direct regulation of psaEFABC. However, the...

Characterization of Zur-dependent genes and direct Zur targets in Yersinia pestis

Background The zinc uptake regulator Zur is a Zn2+-sensing metalloregulatory protein involved in the maintenance of bacterial zinc homeostasis. Up to now, regulation of zinc homeostasis by Zur is poorly understood in Y. pestis. Results We constructed a zur null mutant of Y. pestis biovar microtus strain 201. Microarray expression analysis disclosed a set of 154 Zur-dependent...

Serologic Survey of the Sentinel Animals for Plague Surveillance and Screening for Complementary Diagnostic Markers to F1 Antigen by Protein Microarray

Plague is a deadly infectious disease caused by the gram-negative bacterium, Yersinia pestis. In 2005, five plague patients were confirmed in the Yulong County of the Yunnan Province, China. In this study, the serologic survey of > 2,900 serum samples from domestic dogs and cats in and around the county, where human plague occurred, confirmed that domestic dogs and cats could...

Genome plasticity of Vibrio parahaemolyticus: microevolution of the 'pandemic group'

Background Outbreak of V. parahaemolyticus infections occurred since 1996 was linked to a proposed clonal complex, the pandemic group. The whole genome sequence provides an unprecedented opportunity for dissecting genome plasticity and phylogeny of the populations of V. parahaemolyticus. In the present work, a whole-genome cDNA microarray was constructed to compare the genomic...

Genotyping and Phylogenetic Analysis of Yersinia pestis by MLVA: Insights into the Worldwide Expansion of Central Asia Plague Foci

Background The species Yersinia pestis is commonly divided into three classical biovars, Antiqua, Medievalis, and Orientalis, belonging to subspecies pestis pathogenic for human and the (atypical) non-human pathogenic biovar Microtus (alias Pestoides) including several non-pestis subspecies. Recent progress in molecular typing methods enables large-scale investigations in the...

Involvement of the Post-Transcriptional Regulator Hfq in Yersinia pestis Virulence

Background Yersinia pestis is the causative agent of plague, which is transmitted primarily between fleas and mammals and is spread to humans through the bite of an infected flea or contact with afflicted animals. Hfq is proposed to be a global post-transcriptional regulator that acts by mediating interactions between many regulatory small RNAs (sRNAs) and their mRNA targets...

Identification and characterization of PhoP regulon members in Yersinia pestis biovar Microtus

Background The transcription regulator PhoP has been shown to be important for Y. pestis survival in macrophages and under various in vitro stresses. However, the mechanism by which PhoP promotes bacterial intracellular survival is not fully understood. Our previous microarray analysis suggested that PhoP governed a wide set of cellular pathways in Y. pestis. A series of...

A Dog-Associated Primary Pneumonic Plague in Qinghai Province, China

Background. Primary pneumonic plague (PPP) caused by Yersinia pestis is the most threatening clinical form of plague. An outbreak was reported in July 2009 in Qinghai Province, China. Methods. This outbreak was investigated by clinical, epidemiological, bacteriological, and immunological methods. Multilocus variable number tandem repeat analysis (MLVA) was used to track the...

Insight into Microevolution of Yersinia pestis by Clustered Regularly Interspaced Short Palindromic Repeats

BackgroundYersinia pestis, the pathogen of plague, has greatly influenced human history on a global scale. Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR), an element participating in immunity against phages' invasion, is composed of short repeated sequences separated by unique spacers and provides the basis of the spoligotyping technology. In the present...