scholarly journals Xanthosine Utilization in Salmonella enterica Serovar Typhimurium Is Recovered by a Single Aspartate-to-Glycine Substitution in Xanthosine Phosphorylase

2006 ◽  
Vol 188 (11) ◽  
pp. 4153-4157 ◽  
Author(s):  
Michael Riis Hansen ◽  
Jesper Tranekjær Jørgensen ◽  
Gert Dandanell
Keyword(s):  
Escherichia Coli ◽  
Substrate Specificity ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Kinetic Constants ◽  
Mutant Enzyme ◽  
E Coli ◽  
Serovar Typhimurium ◽  
Glycine Substitution

ABSTRACT xapABR from Salmonella enterica was analyzed and compared with the corresponding Escherichia coli genes. xapB and xapR, but not xapA, encode functional proteins. An S. enterica XapA(Asp72Gly) mutant that restores the phosphorolytic activity was selected. The purified mutant enzyme has different kinetic constants than the E. coli enzyme but similar substrate specificity.

Detection of Escherichia coli O157, Salmonella enterica Serovar Typhimurium, and Staphylococcal Enterotoxin B in a Single Sample Using Enzymatic Bio-Nanotransduction

2007 ◽  
Vol 70 (4) ◽  
pp. 841-850 ◽  
Author(s):  
JOSH R. BRANEN ◽  
MARTHA J. HASS ◽  
ERIN R. DOUTHIT ◽  
WUSI C. MAKI ◽  
A. LARRY BRANEN
Keyword(s):  
Escherichia Coli ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Staphylococcal Enterotoxin B ◽  
Escherichia Coli O157 ◽  
Dna Templates ◽  
E Coli ◽  
Serovar Typhimurium ◽  
Biological Recognition ◽  
Enterotoxin B

Enzymatic bio-nanotransduction is a biological detection scheme based on the production of nucleic acid nano-signals (RNA) in response to specific biological recognition events. In this study, we applied an enzymatic bio-nanotransduction system to the detection of important food-related pathogens and a toxin. Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and staphylococcal enterotoxin B (SEB) were chosen because of the implications of these targets to food safety. Primary antibodies to each of the targets were used to functionalize magnetic beads and produce biological recognition elements (antibodies) conjugated to nano-signal–producing DNA templates. Immunomagnetic capture that was followed by in vitro transcription of DNA templates bound to target molecules produced RNA nano-signals specific for every target in the sample. Discrimination of RNA nano-signals with a standard enzyme-linked oligonucleotide fluorescence assay provided a correlation between nano-signal profiles and target concentrations. The estimated limit of detection was 2.4 × 103 CFU/ml for E. coli O157:H7, 1.9 × 104 CFU/ml for S. enterica serovar Typhimurium, and 0.11 ng/ml for SEB with multianalyte detection in buffer. Low levels of one target were also detected in the presence of interference from high levels of the other targets. Finally, targets were detected in milk, and detection was improved for E. coli O157 by heat treatment of the milk.

scholarly journals Salmonella enterica Serovar Typhimurium and Escherichia coli Survival in Estuarine Bank Sediments

2018 ◽  
Vol 15 (11) ◽  
pp. 2597 ◽  
Author(s):  
Mahbubul Siddiqee ◽  
Rebekah Henry ◽  
Rebecca Coulthard ◽  
Christelle Schang ◽  
Richard Williamson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Growth Patterns ◽  
Estuarine Sediments ◽  
Human Pathogens ◽  
Indicator Organisms ◽  
Fecal Indicator ◽  
E Coli ◽  
Serovar Typhimurium

Estuarine bank sediments have the potential to support the survival and growth of fecal indicator organisms, including Escherichia coli. However, survival of fecal pathogens in estuarine sediments is not well researched and therefore remains a significant knowledge gap regarding public health risks in estuaries. In this study, simultaneous survival of Escherichia coli and a fecal pathogen, Salmonella enterica serovar Typhimurium, was studied for 21 days in estuarine bank sediment microcosms. Observed growth patterns for both organisms were comparable under four simulated scenarios; for continuous-desiccation, extended-desiccation, periodic-inundation, and continuous-inundation systems, logarithmic decay coefficients were 1.54/day, 1.51/day, 0.14/day, and 0.20/day, respectively, for E. coli, and 1.72/day, 1.64/day, 0.21/day, and 0.24/day for S. Typhimurium. Re-wetting of continuous-desiccated systems resulted in potential re-growth, suggesting survival under moisture-limited conditions. Key findings from this study include: (i) Bank sediments can potentially support human pathogens (S. Typhimurium), (ii) inundation levels influence the survival of fecal bacteria in estuarine bank sediments, and (iii) comparable survival rates of S. Typhimurium and E. coli implies the latter could be a reliable fecal indicator in urban estuaries. The results from this study will help select suitable monitoring and management strategies for safer recreational activities in urban estuaries.

scholarly journals Biofilm Formation by Salmonella enterica Serovar Typhimurium and Escherichia coli on Epithelial Cells following Mixed Inoculations

2005 ◽  
Vol 73 (8) ◽  
pp. 5198-5203 ◽  
Author(s):  
Cristina L. C. Esteves ◽  
Bradley D. Jones ◽  
Steven Clegg
Keyword(s):  
Escherichia Coli ◽  
Epithelial Cells ◽  
Salmonella Enterica ◽  
Biofilm Formation ◽  
Salmonella Enterica Serovar Typhimurium ◽  
E Coli ◽  
Serovar Typhimurium

ABSTRACT Biofilms were formed by inoculations of Salmonella enterica serovar Typhimurium and Escherichia coli on HEp-2 cells. Inoculations of S. enterica serovar Typhimurium and E. coli resulted in the formation of an extensive biofilm of S. enterica serovar Typhimurium. In experiments where an E. coli biofilm was first formed followed by challenge with S. enterica serovar Typhimurium, there was significant biofilm formation by S. enterica serovar Typhimurium. The results of this study indicate that S. enterica serovar Typhimurium can outgrow E. coli in heterologous infections and displace E. coli when it forms a biofilm on HEp-2 cells.

scholarly journals Antibiotic Resistance in Salmonella enterica Serovar Typhimurium Exposed to Microcin-Producing Escherichia coli

2001 ◽  
Vol 67 (8) ◽  
pp. 3763-3766 ◽  
Author(s):  
Steve A. Carlson ◽  
Timothy S. Frana ◽  
Ronald W. Griffith
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Salmonella Enterica ◽  
Pathogenic Bacteria ◽  
Defense Mechanism ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Multidrug Resistant ◽  
E Coli ◽  
Resistant Phenotype ◽  
Serovar Typhimurium

ABSTRACT Microcin 24 is an antimicrobial peptide secreted by uropathogenicEscherichia coli. Secretion of microcin 24 provides an antibacterial defense mechanism for E. coli. In a plasmid-based system using transformed Salmonella enterica, we found that resistance to microcin 24 could be seen in concert with a multiple-antibiotic resistance phenotype. This multidrug-resistant phenotype appeared when Salmonella was exposed to an E. coli strain expressing microcin 24. Therefore, it appears that multidrug-resistant Salmonellacan arise as a result of an insult from other pathogenic bacteria.

scholarly journals Genome Sequence of Bacteriophage GG32, Which Can Infect both Salmonella enterica Serovar Typhimurium and Escherichia coli O157:H7

2016 ◽  
Vol 4 (6) ◽  
Author(s):  
Su-Jin Chae ◽  
Taesoo Kwon ◽  
Sunjin Lee ◽  
Yeon Ho Kang ◽  
Gyung Tae Chung ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Genome Sequence ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Control Agent ◽  
Republic Of Korea ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Serovar Typhimurium ◽  
The Republic

We report here a new virulent Salmonella enterica serovar Typhimurium ( S . Typhimurium) bacteriophage, GG32, which was isolated from the Guem River in the Republic of Korea. The strain can infect both S . Typhimurium and Escherichia coli ( E. coli ) O157:H7 and may be a good candidate for a bio-control agent.

scholarly journals The Acyl Homoserine Lactone Receptor, SdiA, of Escherichia coli and Salmonella enterica Serovar Typhimurium Does Not Respond to Indole

2012 ◽  
Vol 78 (15) ◽  
pp. 5424-5431 ◽  
Author(s):  
Anice Sabag-Daigle ◽  
Jitesh A. Soares ◽  
Jenée N. Smith ◽  
Mohamed E. Elmasry ◽  
Brian M. M. Ahmer
Keyword(s):  
Escherichia Coli ◽  
Salmonella Enterica ◽  
Biofilm Formation ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Homoserine Lactone ◽  
Acyl Homoserine Lactone ◽  
Content Type ◽  
E Coli ◽  
Serovar Typhimurium ◽  
High Concentrations

ABSTRACTIn this study, we tested the hypothesis that the SdiA proteins ofEscherichia coliandSalmonella entericaserovar Typhimurium respond to indole. While indole was found to have effects on gene expression and biofilm formation, these effects were notsdiAdependent. However, high concentrations of indole did inhibitN-acyl-l-homoserine lactone (AHL) sensing by SdiA. We conclude that SdiA does not respond to indole but indole can inhibit SdiA activity inE. coliandSalmonella.

Effects of Nitrate or Nitro Supplementation, with or without Added Chlorate, on Salmonella enterica Serovar Typhimurium and Escherichia coli in Swine Feces†

2007 ◽  
Vol 70 (2) ◽  
pp. 308-315 ◽  
Author(s):  
ROBIN C. ANDERSON ◽  
YONG S. JUNG ◽  
CHRISTY E. OLIVER ◽  
SHANE M. HORROCKS ◽  
KENNETH J. GENOVESE ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Active Agent ◽  
Bactericidal Effect ◽  
Nitro Compounds ◽  
E Coli ◽  
Serovar Typhimurium ◽  
Swine Feces ◽  
Respiratory Nitrate Reductase

The effects of coincubating the active agent of an experimental chlorate product with nitrate or select nitro compounds, possible inducers and competing substrates for the targeted respiratory nitrate reductase, on concentrations of experimentally inoculated Salmonella enterica serovar Typhimurium and indigenous Escherichia coli were determined. Studies were completed in swine fecal suspensions as a prelude to the administration of these inhibitors to pigs. Results confirmed the bactericidal effect of chlorate (5 to 10 mM) against these fecal enterobacteria, reducing (P < 0.05) concentrations by >2 log CFU ml−1after 3 to 6 h of incubation. An effect (P < 0.05) of pH was observed, with considerable regrowth of Salmonella and E. coli occurring after 24 h of incubation in suspensions buffered to pH 7.1 but not in suspensions buffered to pH 6.5 or 5.6. A 24-h coincubation of fecal suspensions with 5 to 10 mM chlorate and as little as 2.5 mM nitrate or 10 to 20 mM 2-nitro-1-propanol, 2-nitroethanol, and, sometimes, nitroethane decreased (P < 0.05) Salmonella but not necessarily E. coli concentrations. 2-Nitro-1-propanol and 2-nitroethanol exhibited inhibitory activity against Salmonella and E. coli by an undetermined mechanism, even in the absence of added chlorate.

scholarly journals Generating Tetracycline-Inducible Auxotrophy in Escherichia coli and Salmonella enterica Serovar Typhimurium by Using an Insertion Element and a Hyperactive Transposase

2006 ◽  
Vol 72 (7) ◽  
pp. 4717-4725 ◽  
Author(s):  
Martin Köstner ◽  
Britta Schmidt ◽  
Ralph Bertram ◽  
Wolfgang Hillen
Keyword(s):  
Escherichia Coli ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Insertion Mutant ◽  
Insertion Element ◽  
E Coli ◽  
Auxotrophic Mutants ◽  
Mutant Pool ◽  
Serovar Typhimurium ◽  
Gene Knockouts

ABSTRACT We report the construction and application of a novel insertion element for transposase-mediated mutagenesis in gram-negative bacteria. Besides Kmr as a selectable marker, the insertion element InsTetG−1 carries the anhydrotetracycline (atc)-regulated outward-directed PA promoter so that atc-dependent conditional gene knockouts or knockdowns are generated. The complex formed between the purified hyperactive transposase and InsTetG−1 was electroporated into Escherichia coli or Salmonella enterica serovar Typhimurium, and mutant pools were collected. We used E. coli strains with either TetR or the reverse variant revTetRr2, while only TetR was employed in Salmonella. Screening of the InsTetG−1 insertion mutant pools revealed 15 atc-regulatable auxotrophic mutants for E. coli and 4 atc-regulatable auxotrophic mutants for Salmonella. We have also screened one Salmonella mutant pool in murine macrophage-like J774-A.1 cells using ampicillin enrichment. Two mutants with the InsTetG−1 insertion in the gene pyrE or argA survived this procedure, indicating a reduced intracellular growth rate in J774-A.1 cells. The nature of the mutants and the modes of their regulation are discussed.

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