scholarly journals IroN, a Novel Outer Membrane Siderophore Receptor Characteristic of Salmonella enterica

1998 ◽  
Vol 180 (6) ◽  
pp. 1446-1453 ◽  
Author(s):  
Andreas J. Bäumler ◽  
Tracy L. Norris ◽  
Todd Lasco ◽  
Wolfgang Voigt ◽  
Rolf Reissbrodt ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Salmonella Enterica ◽  
Mutational Analysis ◽  
Iron Acquisition ◽  
Bacterial Species ◽  
Receptor Protein ◽  
Closely Related Species ◽  
E Coli ◽  
Phylogenetic Lineages ◽  
Close Relatives

ABSTRACT Speciation in enterobacteria involved horizontal gene transfer. Therefore, analysis of genes acquired by horizontal transfer that are present in one species but not its close relatives is expected to give insights into how new bacterial species were formed. In this study we characterize iroN, a gene located downstream of theiroBC operon in the iroA locus ofSalmonella enterica serotype Typhi. Like iroBC, the iroN gene is present in all phylogenetic lineages ofS. enterica but is absent from closely related species such as Salmonella bongori or Escherichia coli. Comparison of the deduced amino acid sequence of iroN with other proteins suggested that this gene encodes an outer membrane siderophore receptor protein. Mutational analysis in S. enterica and expression in E. coli identified a 78-kDa outer membrane protein as the iroN gene product. When introduced into an E. coli fepA cir fiu aroB mutant on a cosmid, iroN mediated utilization of structurally related catecholate siderophores, includingN-(2,3-dihydroxybenzoyl)-l-serine, myxochelin A, benzaldehyde-2,3-dihydroxybenzhydrazone, 2-N,6-N-bis(2,3-dihydroxybenzoyl)-l-lysine, 2-N,6-N-bis(2,3-dihydroxybenzoyl)-l-lysine amide, and enterochelin. These results suggest that theiroA locus functions in iron acquisition in S. enterica.

scholarly journals Identification of rhtX and fptX, Novel Genes Encoding Proteins That Show Homology and Function in the Utilization of the Siderophores Rhizobactin 1021 by Sinorhizobium meliloti and Pyochelin by Pseudomonas aeruginosa, Respectively

2004 ◽  
Vol 186 (10) ◽  
pp. 2996-3005 ◽  
Author(s):  
Páraic Ó Cuív ◽  
Paul Clarke ◽  
Damien Lynch ◽  
Michael O'Connell
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Outer Membrane ◽  
Membrane Transport ◽  
Sinorhizobium Meliloti ◽  
Iron Acquisition ◽  
Membrane Receptor ◽  
Receptor Protein ◽  
Outer Membrane Receptor ◽  
E Coli ◽  
Genes Encoding

ABSTRACT Rhizobactin 1021 is a hydroxymate siderophore produced by the soil bacterium Sinorhizobium meliloti 2011. A regulon comprising rhtA, encoding the outer membrane receptor protein for the ferrisiderophore; the biosynthesis operon rhbABCDEF; and rhrA, the Ara-C-like regulator of the receptor and biosynthesis genes has been previously described. We report the discovery of a gene, located upstream of rhbA and named rhtX (for “rhizobactin transport”), which is required, in addition to rhtA, to confer the ability to utilize rhizobactin 1021 on a strain of S. meliloti that does not naturally utilize the siderophore. Rhizobactin 1021 is structurally similar to aerobactin, which is transported in Escherichia coli via the IutA outer membrane receptor and the FhuCDB inner membrane transport system. E. coli expressing iutA and fhuCDB was found to also transport rhizobactin 1021. We demonstrated that RhtX alone could substitute for FhuCDB to transport rhizobactin 1021 in E. coli. RhtX shows similarity to a number of uncharacterized proteins which are encoded proximal to genes that are either known to be or predicted to be involved in iron acquisition. Among these is PA4218 of Pseudomonas aeruginosa, which is located close to the gene cluster that functions in pyochelin biosynthesis and outer membrane transport. PA4218 was mutated by allelic replacement, and the mutant was found to have a pyochelin utilization-defective phenotype. It is proposed that PA4218 be named fptX (for “ferripyochelin transport”). RhtX and FptX appear to be members of a novel family of permeases that function as single-subunit transporters of siderophores.

scholarly journals First Report of a Foodborne Salmonella enterica Serovar Gloucester (4:i:l,w) ST34 Strain Harboring blaCTX–M–55 and qnrS Genes Located in IS26-Mediated Composite Transposon

2021 ◽  
Vol 12 ◽  
Author(s):  
Lili Li ◽  
Rikke Heidemann Olsen ◽  
Anhua Song ◽  
Jian Xiao ◽  
Chong Wang ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Structural Unit ◽  
Bacterial Species ◽  
Meat Products ◽  
Sequence Type ◽  
E Coli ◽  
Serovar Typhimurium ◽  
Long Read ◽  
Phenotypic And Genotypic Characterization

Extended-spectrum β-lactamases (ESBLs) production and (fluoro)quinolone (FQ) resistance among Salmonella pose a public health threat. The objective of this study was the phenotypic and genotypic characterization of an ESBL-producing and nalidixic acid-resistant Salmonella enterica serovar Gloucester isolate (serotype 4:i:l,w) of sequence type 34 (ST34) from ready-to-eat (RTE) meat products in China. Whole-genome short and long read sequencing (HiSeq and MinION) results showed that it contained blaCTX–M–55, qnrS1, and tetB genes, with blaCTX–M–55 and qnrS1 located in chromosomal IS26-mediated composite transposon (IS26–qnrS1–IS3–Tn3–orf–blaCTX–M–55–ISEcp1–IS26). The same genetic structure was found in the chromosome of S. enterica subsp. enterica serovar Typhimurium strain and in several plasmids of Escherichia coli, indicating that the IS26-mediated composite transposon in the chromosome of S. Gloucester may originate from plasmids of E. coli and possess the ability to disseminate to Salmonella and other bacterial species. Besides, the structural unit qnrS1–IS3–Tn3–orf–blaCTX–M–55 was also observed to be linked with ISKpn19 in both the chromosomes and plasmids of various bacteria species, highlighting the contribution of the insertion sequences (IS26 and ISKpn19) to the co-dissemination of blaCTX–M–55 and qnrS1. To our knowledge, this is the first description of chromosomal blaCTX–M–55 and qnrS in S. Gloucester from RTE meat products. Our work expands the host range and provides additional evidence of the co-transfer of blaCTX–M–55 and qnrS1 among different species of Salmonella through the food chain.

scholarly journals Mechanism of Bactericidal Activity of Microcin L inEscherichia coliandSalmonella enterica

2010 ◽  
Vol 55 (3) ◽  
pp. 997-1007 ◽  
Author(s):  
Natacha Morin ◽  
Isabelle Lanneluc ◽  
Nathalie Connil ◽  
Marie Cottenceau ◽  
Anne Marie Pons ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Bactericidal Activity ◽  
Salmonella Enterica ◽  
Cytoplasmic Membrane ◽  
Genetic System ◽  
Proton Motive Force ◽  
Motive Force ◽  
Membrane Properties ◽  
Outer Membrane Receptor ◽  
E Coli

ABSTRACTFor the first time, the mechanism of action of microcin L (MccL) was investigated in live bacteria. MccL is a gene-encoded peptide produced byEscherichia coliLR05 that exhibits a strong antibacterial activity against relatedEnterobacteriaceae, includingSalmonella entericaserovars Typhimurium and Enteritidis. We first subcloned the MccL genetic system to remove the sequences not involved in MccL production. We then optimized the MccL purification procedure to obtain large amounts of purified microcin to investigate its antimicrobial and membrane properties. We showed that MccL did not induce outer membrane permeabilization, which indicated that MccL did not use this way to kill the sensitive cell or to enter into it. Using a set ofE. coliandSalmonella entericamutants lacking iron-siderophore receptors, we demonstrated that the MccL uptake required the outer membrane receptor Cir. Moreover, the MccL bactericidal activity was shown to depend on the TonB protein that transduces the proton-motive force of the cytoplasmic membrane to transport iron-siderophore complexes across the outer membrane. Using carbonyl cyanide 3-chlorophenylhydrazone, which is known to fully dissipate the proton-motive force, we proved that the proton-motive force was required for the bactericidal activity of MccL onE. coli. In addition, we showed that a primary target of MccL could be the cytoplasmic membrane: a high level of MccL disrupted the inner membrane potential ofE. colicells. However, no permeabilization of the membrane was detected.

scholarly journals Carriage of Cdt-B Encoding Campylobacter spp., Salmonella Enterica, and Yersinia Entercolitica in Patients With Gastroenteritis and Irritable Bowel Syndrome

2020 ◽  
Author(s):  
Leila Ganji ◽  
Mohammad Hassan Shirazi ◽  
Masoud Alebouyeh ◽  
Parisa Eslami ◽  
Mohammad Rahbar ◽  
...  
Keyword(s):  
Irritable Bowel Syndrome ◽  
Salmonella Enterica ◽  
Demographic Data ◽  
Bacterial Species ◽  
Healthy People ◽  
Control Group ◽  
Toxic Activity ◽  
E Coli ◽  
Stool Samples ◽  
Irritable Bowel

Abstract Introduction: Cytolethal distending toxin (Cdt) is one of the bacterial toxins that present in a variety of Gram-negative human pathogens, such as E. coli, Salmonella spp., and Campylobacter spp. CDT composed of three subunits encoded by three adjacent genes, including cdtA, cdtB and cdtC. It is approved that cdtB had toxic activity and caused DNA damage of the host cell. Despite its presence in different bacterial species, role of Cdt in acute and chronic infections, such as gastroenteritis and irritable bowel syndrome (IBS) is unclear. To analyze this correlation, we studied the prevalence of cdtB among different enteropathogenic bacteria in patients with gastroenteritis and IBS compared with healthy people.Materials and Methods: In this cross-sectional descriptive study, 230 stool samples were collected from patients with gastroenteritis, IBS, and healthy people. The presence of Cdt-B encoding bacteria, including Escherichia coli, Campylobacter spp., Yersinia entercolitica, Providencia alkalifacience, and Salmonella enterica was examined by polymerase chain reaction using genus specific primers. Results: Out of 230 stool samples, Cdt-B encoding Campylobacter spp. were found in 34.6% (52/150), 6.25% (5/80), and 4% (2/50) of the patients with gastroenteritis, IBS, and the control group, respectively. Carriage of Cdt-B encoding Salmonella enterica was characterized among 5.3% (8/150) of the patients with gastroenteritis and 17.5% (14/80) of the IBS patients. Although none of the patients carried cdtB of E. coli and Providencia spp., cdtB of Y. enterocolitica was detected in 1 of the patients with gastroenteritis (0.6%). Statistical analysis showed significant correlation between infection with CdtB-encoding Campylobacter spp. and IBS-D subtype. No significant correlation was found between infection with Cdt-B encoding bacteria, and other clinical and demographic data.Conclusion: Our results confirmed relatively higher frequency of Cdt-B encoding bacteria in the intestine of IBS patients and those with gastroenteritis compared with healthy individuals. Regarding the frequency of Cdt-B encoding Salmonella and Campylobacter bacteria, it was proposed that infection with these enteropathogens could be considered as a risk factor for the development or progression of IBS among the Iranian patients. Further studies are needed to establish this involvemet.

scholarly journals Colicin E1 Fragments Potentiate Antibiotics by Plugging TolC

2019 ◽  
Author(s):  
S. Jimmy Budiardjo ◽  
Jacqueline J. Deay ◽  
Anna L. Calkins ◽  
Virangika K. Wimalasena ◽  
Daniel Montezano ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Single Molecule ◽  
Outer Membrane Protein ◽  
Efflux Pump ◽  
Bacterial Species ◽  
Outer Membrane Proteins ◽  
E Coli ◽  
Colicin E1 ◽  
Antibiotic Efflux

AbstractThe double membrane architecture of Gram-negative bacteria forms a barrier that is effectively impermeable to extracellular threats. Accordingly, researchers have shown increasing interest in developing antibiotics that target the accessible, surface-exposed proteins embedded in the outer membrane. TolC forms the outer membrane channel of an antibiotic efflux pump in Escherichia coli. Drawing from prior observations that colicin E1, a toxin produced by and lethal to E. coli, can bind to the TolC channel, we investigate the capacity of colicin E1 fragments to ‘plug’ TolC and inhibit its efflux function. First, using single-molecule fluorescence, we show that colicin E1 fragments that do not include the cytotoxic domain localize at the cell surface. Next, using real-time efflux measurements and minimum inhibitory concentration assays, we show that exposure of wild-type E. coli to fragments of colicin E1 indeed disrupts TolC efflux and heightens bacterial susceptibility to four common classes of antibiotics. This work demonstrates that extracellular plugging of outer membrane transporters can serve as a novel method to increase antibiotic susceptibility. In addition to the utility of these protein fragments as starting points for the development of novel antibiotic potentiators, the variety of outer membrane protein colicin binding partners provides an array of options that would allow our method to be used to inhibit other outer membrane protein functions.SignificanceWe find that fragments of a protein natively involved in intraspecies bacterial warfare can be exploited to plug the E. coli outer membrane antibiotic efflux machinery. This plugging disables a primary form of antibiotic resistance. Given the diversity of bacterial species of similar bacterial warfare protein targets, we anticipate that this method of plugging is generalizable to disabling the antibiotic efflux of other proteobacteria. Moreover, given the diversity of the targets of bacterial warfare proteins, this method could be used for disabling the function of a wide variety of other bacterial outer membrane proteins.

scholarly journals Overcoming Iron Deficiency of anEscherichia colitonBMutant by Increasing Outer Membrane Permeability

2019 ◽  
Vol 201 (17) ◽  
Author(s):  
Nan Qiu ◽  
Rajeev Misra
Keyword(s):  
Membrane Permeability ◽  
Outer Membrane ◽  
Membrane Integrity ◽  
Receptor Protein ◽  
Permeability Barrier ◽  
Prolonged Incubation ◽  
Content Type ◽  
E Coli ◽  
Outer Membrane Permeability

ABSTRACTThe intake of certain nutrients, including ferric ion, is facilitated by the outer membrane-localized transporters. Due to ferric insolubility at physiological pH,Escherichia colisecretes a chelator, enterobactin, outside the cell and then transports back the enterobactin-ferric complex via an outer membrane receptor protein, FepA, whose activity is dependent on the proton motive force energy transduced by the TonB-ExbBD complex of the inner membrane. Consequently, ΔtonBmutant cells grow poorly on a medium low in iron. Prolonged incubation of ΔtonBcells on low-iron medium yields faster-growing colonies that acquired suppressor mutations in theyejM(pbgA) gene, which codes for a putative inner-to-outer membrane cardiolipin transporter. Further characterization of suppressors revealed that they display hypersusceptibility to vancomycin, a large hydrophilic antibiotic normally precluded from enteringE. colicells, and leak periplasmic proteins into the culture supernatant, indicating a compromised outer membrane permeability barrier. All phenotypes were reversed by supplying the wild-type copy ofyejMon a plasmid, suggesting thatyejMmutations are solely responsible for the observed phenotypes. The deletion of all known cardiolipin synthase genes (clsABC) did not produce the phenotypes similar to mutations in theyejMgene, suggesting that the absence of cardiolipin from the outer membraneper seis not responsible for increased outer membrane permeability. Elevated lysophosphatidylethanolamine levels and the synthetic growth phenotype withoutpldAindicated that defective lipid homeostasis in theyejMmutant compromises outer membrane lipid asymmetry and permeability barrier to allow enterobactin intake, and that YejM has additional roles other than transporting cardiolipin.IMPORTANCEThe work presented here describes a positive genetic selection strategy for isolating mutations that destabilize the outer membrane permeability barrier ofE. coli. Given the importance of the outer membrane in restricting the entry of antibiotics, characterization of the genes and their products that affect outer membrane integrity will enhance the understanding of bacterial membranes and the development of strategies to bypass the outer membrane barrier for improved drug efficacy.

Biofilm Formation by Multidrug-Resistant Salmonella enterica Serotype Typhimurium Phage Type DT104 and Other Pathogens

2007 ◽  
Vol 70 (1) ◽  
pp. 22-29 ◽  
Author(s):  
SHIN-HEE KIM ◽  
CHENG-I WEI
Keyword(s):  
Stainless Steel ◽  
Salmonella Typhimurium ◽  
Salmonella Enterica ◽  
Bacterial Species ◽  
Phage Type ◽  
Meat Products ◽  
Multidrug Resistant ◽  
E Coli ◽  
Retail Meat ◽  
Glass Surfaces

The biofilm-forming capability of Salmonella enterica serotypes Typhimurium and Heidelberg, Pseudomonas aeruginosa, Listeria monocytogenes, Escherichia coli O157:H7, Klebsiella pneumoniae, and Acinetobacter baumannii isolated from humans, animal farms, and retail meat products was evaluated by using a microplate assay. The tested bacterial species showed interstrain variation in their capabilities to form biofilms. Strong biofilm-forming strains of S. enterica serotypes, E. coli O157: H7, P. aeruginosa, K. pneumoniae, and A. baumannii were resistant to at least four of the tested antibiotics. To understand their potential in forming biofilms in food-processing environments, the strong biofilm formers grown in beef, turkey, and lettuce broths were further investigated on stainless steel and glass surfaces. Among the tested strains, Salmonella Typhimurium phage type DT104 (Salmonella Typhimurium DT104) isolated from retail beef formed the strongest biofilm on stainless steel and glass in beef and turkey broths. K. pneumoniae, L. monocytogenes, and P. aeruginosa were also able to form strong biofilms on the tested surface materials. Salmonella Typhimurium DT104 developed a biofilm on stainless steel in beef and turkey broths through (i) initial attachment to the surface, (ii) formation of microcolonies, and (iii) biofilm maturation. These findings indicated that Salmonella Typhimurium DT104 along with other bacterial pathogens could be a source of cross-contamination during handling and processing of food.

Structure of bacteriophage lambda receptor protein

1983 ◽  
Vol 41 ◽  
pp. 736-737
Author(s):  
Bing K. Jap ◽  
Robert M. Glaeser
Keyword(s):  
Outer Membrane ◽  
Diffraction Pattern ◽  
Hexagonal Lattice ◽  
Biochemical Properties ◽  
Optical Diffraction ◽  
Matrix Proteins ◽  
Receptor Protein ◽  
E Coli ◽  
Lattice Constants ◽  
First Order

Receptor protein for phage lambda (LamB protein) is a major outer membrane protein in maltose-induced E. coli cells. This protein (M.W. ∼48,000) facilitates the passage of maltose, maltooligosaccharides and other sugars across the outer membrane. LamB and matrix proteins (OmpC and OmpF) form permeability channels and share a number of unique physical and biochemical properties. Yamada et al. have carried out experiments reconstituting LamB proteins with 1ipopolysaccharides, 1ipopolysaccharide derivatives, fatty acids, and phospholipid. The reconstituted specimens show first order hexagonal lattice with lattice constants that vary with the reconstitution component.We have reconstituted LamB protein with phosphatidylcholine from soybean. The reconstituted LamB membrane patches have dimensions from 0.2 μm to 3 μm in diameter with typical size of about 0.4 μm. LamB specimens negatively stained with phosphotungstic acid is shown in Figure l together with its optical diffraction pattern. The optical diffraction pattern shows a hexagonal lattice with lattice constant ∼7.2 nm. The diffraction intensities extend to a resolution of ∼2.4 nm.

scholarly journals Rapid Oligonucleotide-Based Recombineering of the Chromosome of Salmonella enterica

2009 ◽  
Vol 75 (6) ◽  
pp. 1575-1580 ◽  
Author(s):  
Roman G. Gerlach ◽  
Daniela Jäckel ◽  
Stefanie U. Hölzer ◽  
Michael Hensel
Keyword(s):  
Salmonella Enterica ◽  
Mutational Analysis ◽  
Bacterial Species ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Synthetic Dna ◽  
Chromosomal Genes ◽  
Bacterial Chromosomes ◽  
Chromosomal Loci

ABSTRACT Recombinant engineering using Red recombinase-based approaches offers efficient and rapid approaches to deletion and modification of genes. Here we describe a novel application of Red recombinant engineering that enables direct manipulation of chromosomal loci by electroporation with short synthetic DNA molecules. We demonstrate the use of this approach for the generation of scarless in-frame deletions in chromosomal genes of Salmonella enterica. Furthermore, we describe rapid site-directed mutagenesis within bacterial chromosomes without any requirement for cloning and mutating genes in vitro or for reintroducing mutant alleles into the chromosome. This approach can be expected to facilitate mutational analysis in S. enterica and in other bacterial species able to support Red-mediated recombination.

scholarly journals Carriage of Cdt-B Encoding Campylobacter spp., Salmonellaenterica, and Yersinia entercolitica in Patients with Gastroenteritis, Irritable Bowel Syndrome, and Controls

2021 ◽  
Author(s):  
Leila Ganji ◽  
Mohmmad Hassan Shirazi ◽  
Masoud Alebouyeh ◽  
Parisa Eslami ◽  
Naser Ebrahim Daryani ◽  
...  
Keyword(s):  
Irritable Bowel Syndrome ◽  
Salmonella Enterica ◽  
Demographic Data ◽  
Bacterial Species ◽  
Healthy People ◽  
Control Group ◽  
Toxic Activity ◽  
E Coli ◽  
Stool Samples ◽  
Irritable Bowel

Abstract Background: Cytolethal distending toxin (Cdt) is one of the bacterial toxins that present in a variety of Gram-negative human pathogens, such as E. coli, Salmonella spp., and Campylobacter spp. CDT composed of three subunits encoded by three adjacent genes, including cdtA, cdtB and cdtC. It is approved that cdtB had toxic activity and caused DNA damage of the host cell. Despite its presence in different bacterial species, role of Cdt in acute and chronic infections, such as gastroenteritis and irritable bowel syndrome (IBS), is unclear. To analyze this correlation, we studied the prevalence of cdtB among different enteropathogenic bacteria in patients with gastroenteritis and IBS compared with healthy people. Materials and Methods: In this cross-sectional descriptive study, 230 stool samples were collected from patients with gastroenteritis, IBS, and healthy people. The presence of Cdt-B encoding bacteria, including Escherichia coli, Campylobacter spp., Yersinia entercolitica, Providencia alkalifacience, and Salmonella enterica was examined by polymerase chain reaction. Demographic data and type of disease was collected through interview and a questionnaire.Results: Out of 230 stool samples, Cdt-B encoding Campylobacter spp. were found in 34.6% (52/150), 6.25% (5/80), and 4% (2/50) of the patients with gastroenteritis, IBS, and the control group, respectively. Carriage of Cdt-B encoding Salmonella enterica was characterized among 5.3% (8/150) of the patients with gastroenteritis and 17.5% (14/80) of the IBS patients. Although none of the patients carried cdtB of E. coli and Providencia spp., cdtB of Y. enterocolitica was detected in 1 of the patients with gastroenteritis (0.6%). Statistical analysis showed significant correlation between infection with CdtB-encoding Campylobacter spp. and IBS-D subtype. No significant correlation was found between infection with Cdt-B encoding bacteria, and other clinical and demographic data.Conclusions: Our results confirmed relatively higher frequency of Cdt-B encoding bacteria in the intestine of IBS patients and those with gastroenteritis compared with healthy individuals. Regarding the frequency of Cdt-B encoding Salmonella and Campylobacter bacteria, it was proposed that infection with these enteropathogens could be considered as a risk factor for the development or progression of IBS among the Iranian patients. Further studies are needed to establish this involvement.

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