VceR negatively regulates the vceCAB MDR efflux operon and positively regulates its own synthesis in Vibrio cholerae 569B

2007 ◽  
Vol 53 (7) ◽  
pp. 888-900 ◽  
Author(s):  
Adnan A. Alatoom ◽  
Ricardo Aburto ◽  
Abdul N. Hamood ◽  
Jane A. Colmer-Hamood
Keyword(s):  
Vibrio Cholerae ◽  
Growth Cycle ◽  
Transcriptional Analysis ◽  
Transcriptional Fusion ◽  
Detailed Characterization ◽  
Repressive Effect ◽  
Carbonyl Cyanide ◽  
In Trans

The vceCAB (vce) operon encodes the multidrug resistance pump VceCAB (VCE), which contributes to resistance of Vibrio cholerae to carbonyl cyanide m-chlorophenylhydrazine (CCCP), deoxycholate, and pentachlorophenol by several-fold. vceR, which encodes the TetR-type repressor VceR and is divergently transcribed from vce, has been characterized in Escherichia coli . Detailed characterization of vceR in V. cholerae 569B confirmed the repressive effect of VceR on VCE function and indicated several novel features of VceR. Deletion of vceR increased resistance of strain 569B to CCCP and deoxycholate modestly, but did not affect resistance to pentachlorophenol. Transcriptional analysis revealed that vce expression was not only increased in strain 569BΔvceR::Ω by 2-fold but continued to rise throughout the growth cycle. Using a vceR–lux transcriptional fusion plasmid, we examined whether vceR is autoregulated in strain 569B. Expression of vceR from the vceR–lux fusion was significantly lower in strain 569BΔvceR::Ω than in strain 569B. In addition, exposure to CCCP reduced vceR expression from the vceR–lux fusion in strain 569B but not in strain 569BΔvceR::Ω. Despite differences in the VceR binding site in strain 569B from the previously recognized 28 bp sequence in V. cholerae CVD101, purified recombinant VceR bound to the 24 bp sequence from strain 569B. We propose that VceR modulates vce expression by binding in vivo to the 24 bp sequence within the vceR–vce intergenic region; unlike many TetR repressors that are negatively autoregulated, VceR positively regulates vceR expression in trans.

scholarly journals Regulatory Effects of CsrA in Vibrio cholerae

mBio ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Heidi A. Butz ◽  
Alexandra R. Mey ◽  
Ashley L. Ciosek ◽  
Alexander A. Crofts ◽  
Bryan W. Davies ◽  
...  
Keyword(s):  
Gene Expression ◽  
Vibrio Cholerae ◽  
Virulence Gene ◽  
Growth Cycle ◽  
Mammalian Host ◽  
Aqueous Environment ◽  
Content Type ◽  
Human Host

ABSTRACT CsrA is a posttranscriptional global regulator in Vibrio cholerae. Although CsrA is critical for V. cholerae survival within the mammalian host, the regulatory targets of CsrA remain mostly unknown. To identify pathways controlled by CsrA, RNA-seq transcriptome analysis was carried out by comparing the wild type and the csrA mutant grown to early exponential, mid-exponential, and stationary phases of growth. This enabled us to identify the global effects of CsrA-mediated regulation throughout the V. cholerae growth cycle. We found that CsrA regulates 22% of the V. cholerae transcriptome, with significant regulation within the gene ontology (GO) processes that involve amino acid transport and metabolism, central carbon metabolism, lipid metabolism, iron uptake, and flagellum-dependent motility. Through CsrA-RNA coimmunoprecipitation experiments, we found that CsrA binds to multiple mRNAs that encode regulatory proteins. These include transcripts encoding the major sigma factors RpoS and RpoE, which may explain how CsrA regulation affects such a large proportion of the V. cholerae transcriptome. Other direct targets include flrC, encoding a central regulator in flagellar gene expression, and aphA, encoding the virulence gene transcription factor AphA. We found that CsrA binds to the aphA mRNA both in vivo and in vitro, and CsrA significantly increases AphA protein synthesis. The increase in AphA was due to increased translation, not transcription, in the presence of CsrA, consistent with CsrA binding to the aphA transcript and enhancing its translation. CsrA is required for the virulence of V. cholerae and this study illustrates the central role of CsrA in virulence gene regulation. IMPORTANCE Vibrio cholerae, a Gram-negative bacterium, is a natural inhabitant of the aqueous environment. However, once ingested, this bacterium can colonize the human host and cause the disease cholera. In order to successfully transition between its aqueous habitat and the human host, the bacterium must sense changes in its environment and rapidly alter gene expression. Global regulators, including CsrA, play an integral role in altering the expression of a large number of genes to promote adaptation and survival, which is required for intestinal colonization. We used transcriptomics and a directed CsrA-RNA coimmunoprecipitation to characterize the CsrA regulon and found that CsrA alters the expression of more than 800 transcripts in V. cholerae. Processes regulated by CsrA include motility, the rugose phenotype, and virulence pathways. CsrA directly binds to the aphA transcript and positively regulates the production of the virulence regulator AphA. Thus, CsrA regulates multiple processes that have been linked to pathogenesis.

scholarly journals Proteomic Analysis of Vibrio cholerae in Human Stool

2008 ◽  
Vol 76 (9) ◽  
pp. 4145-4151 ◽  
Author(s):  
Regina C. LaRocque ◽  
Bryan Krastins ◽  
Jason B. Harris ◽  
Lauren M. Lebrun ◽  
Kenneth C. Parker ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Pathogenic Bacteria ◽  
Human Infection ◽  
Effective Vaccine ◽  
Outer Membrane Porin ◽  
Stool Samples ◽  
Acute Phase Serum ◽  
Human Stool

ABSTRACT An effective vaccine for Vibrio cholerae is not yet available for use in the developing world, where the burden of cholera disease is highest. Characterizing the proteins that are expressed by V. cholerae in the human host environment may provide insight into the pathogenesis of cholera and assist with the development of an improved vaccine. We analyzed the V. cholerae proteins present in the stools of 32 patients with clinical cholera. The V. cholerae outer membrane porin, OmpU, was identified in all of the human stool samples, and many V. cholerae proteins were repeatedly identified in separate patient samples. The majority of V. cholerae proteins identified in human stool are involved in protein synthesis and energy metabolism. A number of proteins involved in the pathogenesis of cholera, including the A and B subunits of cholera toxin and the toxin-coregulated pilus, were identified in human stool. In a subset of stool specimens, we also assessed which in vivo expressed V. cholerae proteins were recognized uniquely by convalescent-phase as opposed to acute-phase serum from cholera patients. We identified a number of these in vivo expressed proteins as immunogenic during human infection. To our knowledge, this is the first characterization of the proteome of a pathogenic bacteria recovered from a natural host.

Generation and In Vivo Characterization of Tn5-Induced Biofilm Mutants of Vibrio cholerae O139

2018 ◽  
Vol 75 (10) ◽  
pp. 1324-1333 ◽  
Author(s):  
Preeti Gupta ◽  
Bharti Mankere ◽  
Shami Chekkoora Keloth ◽  
Urmil Tuteja ◽  
Kulanthaivel Thava Chelvam
Keyword(s):  
Vibrio Cholerae ◽  
Vibrio Cholerae O139 ◽  
In Vivo Characterization

scholarly journals Surface antigenic profile and globin phenotype of two new human erythroleukemia lines: characterization and interpretations

Blood ◽  
1988 ◽  
Vol 72 (3) ◽  
pp. 1029-1038 ◽  
Author(s):  
T Papayannopoulou ◽  
B Nakamoto ◽  
S Kurachi ◽  
M Tweeddale ◽  
H Messner
Keyword(s):  
Surface Antigens ◽  
Hematopoietic Differentiation ◽  
Detailed Characterization ◽  
Antigenic Profile

Detailed characterization of the composite phenotype of two newly established erythroleukemia lines (OCIM1, OCIM2) shows that these lines share many of their erythroid markers (ie, surface antigens and globin program) as well as several of their nonerythroid properties (myeloid/monocytic/megakaryocytic) with the two known erythroleukemia lines (K562, HEL). In addition, each displays novel and instructive features. We argue that the surface and globin phenotype of all erythroleukemia lines is nonrandom and that it may be of physiologic relevance; it could represent the most prevalent phenotype of cells transformed by leukemia in vivo, and it raises the possibility that cells with similar potentials exist transiently during normal hematopoietic differentiation before their irreversible commitment to a single lineage. As such, these cells demonstrate a greater phenotypic adaptability in vitro than do their single lineage-committed counterparts since they can differentiate toward more than one lineage.

scholarly journals Structural Connectivity-Based Parcellation of the Dopaminergic Midbrain in Healthy Subjects and Schizophrenic Patients

Medicina ◽  
2020 ◽  
Vol 56 (12) ◽  
pp. 686
Author(s):  
Gianpaolo Antonio Basile ◽  
Alessia Bramanti ◽  
Salvatore Bertino ◽  
Giuseppina Cutroneo ◽  
Antonio Bruno ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Structural Connectivity ◽  
Structural Features ◽  
Detailed Characterization ◽  
Diffusion Tractography ◽  
Core Feature ◽  
Schizophrenic Patients ◽  
Anatomical Research

Background and objectives: Functional deregulation of dopaminergic midbrain regions is a core feature of schizophrenia pathophysiology. Anatomical research on primates suggests that these regions may be subdivided into distinct, topographically organized functional territories according to their connectivity to the striatum. The aim of the present work was the reconstruction of dopaminergic midbrain subregions in healthy subjects and schizophrenic patients and the evaluation of their structural connectivity profiles. Materials and Methods: A hypothesis-driven connectivity-based parcellation derived from diffusion tractography was applied on 24 healthy subjects and 30 schizophrenic patients to identify distinct territories within the human dopaminergic midbrain in vivo and non-invasively. Results: We identified a tripartite subdivision of dopaminergic midbrain, including limbic, prefrontal and sensorimotor territories. No significant differences in structural features or connectivity were found between subjects and patients. Conclusions: The parcellation scheme proposed herein may help to achieve detailed characterization of structural and functional anomalies of the dopaminergic midbrain in schizophrenic patients.

scholarly journals Role of Cyclic Di-GMP during El Tor Biotype Vibrio cholerae Infection: Characterization of the In Vivo-Induced Cyclic Di-GMP Phosphodiesterase CdpA

2008 ◽  
Vol 76 (4) ◽  
pp. 1617-1627 ◽  
Author(s):  
Rita Tamayo ◽  
Stefan Schild ◽  
Jason T. Pratt ◽  
Andrew Camilli
Keyword(s):  
Small Intestine ◽  
Vibrio Cholerae ◽  
Biofilm Formation ◽  
Virulence Gene ◽  
Virulence Gene Expression ◽  
Infant Mouse

ABSTRACT In Vibrio cholerae, the second messenger cyclic di-GMP (c-di-GMP) positively regulates biofilm formation and negatively regulates virulence and is proposed to play an important role in the transition from persistence in the environment to survival in the host. Herein we describe a characterization of the infection-induced gene cdpA, which encodes both GGDEF and EAL domains, which are known to mediate diguanylate cyclase and c-di-GMP phosphodiesterase (PDE) activities, respectively. CdpA is shown to possess PDE activity, and this activity is regulated by its inactive degenerate GGDEF domain. CdpA inhibits biofilm formation but has no effect on colonization of the infant mouse small intestine. Consistent with these observations, cdpA is expressed during in vitro growth in a biofilm but is not expressed in vivo until the late stage of infection, after colonization has occurred. To test for a role of c-di-GMP in the early stages of infection, we artificially increased c-di-GMP and observed reduced colonization. This was attributed to a significant reduction in toxT transcription during infection. Cumulatively, these results support a model of the V. cholerae life cycle in which c-di-GMP must be down-regulated early after entering the small intestine and maintained at a low level to allow virulence gene expression, colonization, and motility at appropriate stages of infection.

scholarly journals Surface antigenic profile and globin phenotype of two new human erythroleukemia lines: characterization and interpretations

Blood ◽  
1988 ◽  
Vol 72 (3) ◽  
pp. 1029-1038 ◽  
Author(s):  
T Papayannopoulou ◽  
B Nakamoto ◽  
S Kurachi ◽  
M Tweeddale ◽  
H Messner
Keyword(s):  
Surface Antigens ◽  
Hematopoietic Differentiation ◽  
Detailed Characterization ◽  
Antigenic Profile

Abstract Detailed characterization of the composite phenotype of two newly established erythroleukemia lines (OCIM1, OCIM2) shows that these lines share many of their erythroid markers (ie, surface antigens and globin program) as well as several of their nonerythroid properties (myeloid/monocytic/megakaryocytic) with the two known erythroleukemia lines (K562, HEL). In addition, each displays novel and instructive features. We argue that the surface and globin phenotype of all erythroleukemia lines is nonrandom and that it may be of physiologic relevance; it could represent the most prevalent phenotype of cells transformed by leukemia in vivo, and it raises the possibility that cells with similar potentials exist transiently during normal hematopoietic differentiation before their irreversible commitment to a single lineage. As such, these cells demonstrate a greater phenotypic adaptability in vitro than do their single lineage-committed counterparts since they can differentiate toward more than one lineage.

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