Comparative Study of Two Transport Systems for Vibrio Cholerae

1994 ◽  
Vol 24 (1) ◽  
pp. 35-36 ◽  
Author(s):  
S Estrada ◽  
E Jaramillo ◽  
M Gaviria ◽  
S Ospina
Keyword(s):  
Comparative Study ◽  
Vibrio Cholerae ◽  
Transport Systems

scholarly journals Vibrio cholerae VciB Mediates Iron Reduction

2017 ◽  
Vol 199 (12) ◽  
Author(s):  
Eric D. Peng ◽  
Shelley M. Payne
Keyword(s):  
Electron Transport ◽  
Vibrio Cholerae ◽  
Ferrous Iron ◽  
Electron Transport Chain ◽  
Iron Reduction ◽  
Iron Transport ◽  
Ferric Iron ◽  
Transport Systems ◽  
Content Type ◽  
Transport Chain

ABSTRACT Vibrio cholerae is the causative agent of the severe diarrheal disease cholera. V. cholerae thrives within the human host, where it replicates to high numbers, but it also persists within the aquatic environments of ocean and brackish water. To survive within these nutritionally diverse environments, V. cholerae must encode the necessary tools to acquire the essential nutrient iron in all forms it may encounter. A prior study of systems involved in iron transport in V. cholerae revealed the existence of vciB, which, while unable to directly transport iron, stimulates the transport of iron through ferrous (Fe2+) iron transport systems. We demonstrate here a role for VciB in V. cholerae in which VciB stimulates the reduction of Fe3+ to Fe2+, which can be subsequently transported into the cell with the ferrous iron transporter Feo. Iron reduction is independent of functional iron transport but is associated with the electron transport chain. Comparative analysis of VciB orthologs suggests a similar role for other proteins in the VciB family. Our data indicate that VciB is a dimer located in the inner membrane with three transmembrane segments and a large periplasmic loop. Directed mutagenesis of the protein reveals two highly conserved histidine residues required for function. Taken together, our results support a model whereby VciB reduces ferric iron using energy from the electron transport chain. IMPORTANCE Vibrio cholerae is a prolific human pathogen and environmental organism. The acquisition of essential nutrients such as iron is critical for replication, and V. cholerae encodes a number of mechanisms to use iron from diverse environments. Here, we describe the V. cholerae protein VciB that increases the reduction of oxidized ferric iron (Fe3+) to the ferrous form (Fe2+), thus promoting iron acquisition through ferrous iron transporters. Analysis of VciB orthologs in Burkholderia and Aeromonas spp. suggest that they have a similar activity, allowing a functional assignment for this previously uncharacterized protein family. This study builds upon our understanding of proteins known to mediate iron reduction in bacteria.

scholarly journals A comparative study of the properties of Vibrio cholerae O 139, O1 and other non-O1 strains

1995 ◽  
Vol 42 (4) ◽  
pp. 251-257 ◽  
Author(s):  
R. K. Nandy ◽  
T. K. Sengupta ◽  
S. Mukhopadhyay ◽  
A. C. Ghose
Keyword(s):  
Comparative Study ◽  
Vibrio Cholerae

scholarly journals Characterization of Ferric and Ferrous Iron Transport Systems in Vibrio cholerae

2006 ◽  
Vol 188 (18) ◽  
pp. 6515-6523 ◽  
Author(s):  
Elizabeth E. Wyckoff ◽  
Alexandra R. Mey ◽  
Andreas Leimbach ◽  
Carolyn F. Fisher ◽  
Shelley M. Payne
Keyword(s):  
Vibrio Cholerae ◽  
Transport System ◽  
Iron Transport ◽  
Iron Acquisition ◽  
Shigella Flexneri ◽  
Transport Systems ◽  
Infant Mouse ◽  
Mouse Intestine ◽  
Dependent Transport

ABSTRACT Vibrio cholerae has multiple iron acquisition systems, including TonB-dependent transport of heme and of the catechol siderophore vibriobactin. Strains defective in both of these systems grow well in laboratory media and in the infant mouse intestine, indicating the presence of additional iron acquisition systems. Previously uncharacterized potential iron transport systems, including a homologue of the ferrous transporter Feo and a periplasmic binding protein-dependent ATP binding cassette (ABC) transport system, termed Fbp, were identified in the V. cholerae genome sequence. Clones encoding either the Feo or the Fbp system exhibited characteristics of iron transporters: both repressed the expression of lacZ cloned under the control of a Fur-regulated promoter in Escherichia coli and also conferred growth on a Shigella flexneri mutant that has a severe defect in iron transport. Two other ABC transporters were also evaluated but were negative by these assays. Transport of radioactive iron by the Feo system into the S. flexneri iron transport mutant was stimulated by the reducing agent ascorbate, consistent with Feo functioning as a ferrous transporter. Conversely, ascorbate inhibited transport by the Fbp system, suggesting that it transports ferric iron. The growth of V. cholerae strains carrying mutations in one or more of the potential iron transport genes indicated that both Feo and Fbp contribute to iron acquisition. However, a mutant defective in the vibriobactin, Fbp, and Feo systems was not attenuated in a suckling mouse model, suggesting that at least one other iron transport system can be used in vivo.

scholarly journals Iron and Fur Regulation in Vibrio cholerae and the Role of Fur in Virulence

2005 ◽  
Vol 73 (12) ◽  
pp. 8167-8178 ◽  
Author(s):  
Alexandra R. Mey ◽  
Elizabeth E. Wyckoff ◽  
Vanamala Kanukurthy ◽  
Carolyn R. Fisher ◽  
Shelley M. Payne
Keyword(s):  
Gene Expression ◽  
Vibrio Cholerae ◽  
Iron Acquisition ◽  
Bacterial Species ◽  
Regulation Of Gene Expression ◽  
Transport Systems ◽  
Infant Mouse ◽  
Genes Encoding ◽  
Regulatory Functions

ABSTRACT Regulation of iron uptake and utilization is critical for bacterial growth and for prevention of iron toxicity. In many bacterial species, this regulation depends on the iron-responsive master regulator Fur. In this study we report the effects of iron and Fur on gene expression in Vibrio cholerae. We show that Fur has both positive and negative regulatory functions, and we demonstrate Fur-independent regulation of gene expression by iron. Nearly all of the known iron acquisition genes were repressed by Fur under iron-replete conditions. In addition, genes for two newly identified iron transport systems, Feo and Fbp, were found to be negatively regulated by iron and Fur. Other genes identified in this study as being induced in low iron and in the fur mutant include those encoding superoxide dismutase (sodA), fumarate dehydratase (fumC), bacterioferritin (bfr), bacterioferritin-associated ferredoxin (bfd), and multiple genes of unknown function. Several genes encoding iron-containing proteins were repressed in low iron and in the fur mutant, possibly reflecting the need to reserve available iron for the most critical functions. Also repressed in the fur mutant, but independently of iron, were genes located in the V. cholerae pathogenicity island, encoding the toxin-coregulated pilus (TCP), and genes within the V. cholerae mega-integron. The fur mutant exhibited very weak autoagglutination, indicating a possible defect in expression or assembly of the TCP, a major virulence factor of V. cholerae. Consistent with this observation, the fur mutant competed poorly with its wild-type parental strain for colonization of the infant mouse gut.

scholarly journals The Vibrio cholerae SpeG Spermidine/Spermine N-Acetyltransferase Allosteric Loop and β6-β7 Structural Elements Are Critical for Kinetic Activity

2021 ◽  
Vol 8 ◽  
Author(s):  
Van Thi Bich Le ◽  
Sofiya Tsimbalyuk ◽  
Ee Qi Lim ◽  
Allan Solis ◽  
Darwin Gawat ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Intracellular Signaling ◽  
Point Mutations ◽  
Structural Evolution ◽  
Transport Systems ◽  
Enzyme Kinetic ◽  
Structural Elements ◽  
Allosteric Site ◽  
Kinetic Activity ◽  
Domains Of Life

Polyamines regulate many important biological processes including gene expression, intracellular signaling, and biofilm formation. Their intracellular concentrations are tightly regulated by polyamine transport systems and biosynthetic and catabolic pathways. Spermidine/spermine N-acetyltransferases (SSATs) are catabolic enzymes that acetylate polyamines and are critical for maintaining intracellular polyamine homeostasis. These enzymes belong to the Gcn5-related N-acetyltransferase (GNAT) superfamily and adopt a highly conserved fold found across all kingdoms of life. SpeG is an SSAT protein found in a variety of bacteria, including the human pathogen Vibrio cholerae. This protein adopts a dodecameric structure and contains an allosteric site, making it unique compared to other SSATs. Currently, we have a limited understanding of the critical structural components of this protein that are required for its allosteric behavior. Therefore, we explored the importance of two key regions of the SpeG protein on its kinetic activity. To achieve this, we created various constructs of the V. cholerae SpeG protein, including point mutations, a deletion, and chimeras with residues from the structurally distinct and non-allosteric human SSAT protein. We measured enzyme kinetic activity toward spermine for ten constructs and crystallized six of them. Ultimately, we identified specific portions of the allosteric loop and the β6-β7 structural elements that were critical for enzyme kinetic activity. These results provide a framework for further study of the structure/function relationship of SpeG enzymes from other organisms and clues toward the structural evolution of members of the GNAT family across domains of life.

scholarly journals A comparative study among clinical and environmental isolates of Vibrio cholerae at their antibiotic

2011 ◽  
Vol 5 (3) ◽  
pp. 22-28
Author(s):  
A. N. Al- Thwani ◽  
K. A. Al- Khafaji
Keyword(s):  
Comparative Study ◽  
Vibrio Cholerae ◽  
Molecular Level ◽  
Plasmid Profile ◽  
Environmental Isolates ◽  
High Susceptibility

in this study, the comparison of the antibiogram and molecular level among different serotype of clinical and environmental isolates of V. cholerae was done. Antibiogram of five clinical and three environmental isolates showed high susceptibility to all tested antibiotics, but non-O1 serotype had Ampicilin resistant. Plasmid profile screening revealed that V. cholerae O1 isolates and non-O1 Dial131 had no small size plasmid while non-O1 ab, 1J, 1R harbored three different small size plasmids with different appearance profile, two mega plasmids detected in the O1 isolate and only one mega plasmid resolute in non-O1 clinical and environmental isolates.

scholarly journals A Multifunctional ATP-Binding Cassette Transporter System from Vibrio cholerae Transports Vibriobactin and Enterobactin

1999 ◽  
Vol 181 (24) ◽  
pp. 7588-7596 ◽  
Author(s):  
Elizabeth E. Wyckoff ◽  
Ana-Maria Valle ◽  
Stacey L. Smith ◽  
Shelley M. Payne
Keyword(s):  
Vibrio Cholerae ◽  
Iron Transport ◽  
Cytoplasmic Membrane ◽  
Signal Sequence ◽  
Biosynthetic Gene Cluster ◽  
Transport Systems ◽  
E Coli ◽  
Amino Terminal ◽  
Atp Binding Cassette Transporter ◽  
Membrane Lipoprotein

ABSTRACT Vibrio cholerae uses the catechol siderophore vibriobactin for iron transport under iron-limiting conditions. We have identified genes for vibriobactin transport and mapped them within the vibriobactin biosynthetic gene cluster. Within this genetic region we have identified four genes, viuP, viuD,viuG and viuC, whose protein products have homology to the periplasmic binding protein, the two integral cytoplasmic membrane proteins, and the ATPase component, respectively, of other iron transport systems. The amino-terminal region of ViuP has homology to a lipoprotein signal sequence, and ViuP could be labeled with [3H]palmitic acid. This suggests that ViuP is a membrane lipoprotein. The ViuPDGC system transports both vibriobactin and enterobactin in Escherichia coli. In the same assay, the E. coli enterobactin transport system, FepBDGC, allowed the utilization of enterobactin but not vibriobactin. Although the entire viuPDGC system could complement mutations infepB, fepD, fepG, orfepC, only viuC was able to independently complement the corresponding fep mutation. This indicates that these proteins usually function as a complex. V. cholerae strains carrying a mutation in viuP or inviuG were constructed by marker exchange. These mutations reduced, but did not completely eliminate, vibriobactin utilization. This suggests that V. cholerae contains genes in addition to viuPDGC that function in the transport of catechol siderophores.

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