scholarly journals Low tyrosine content of growth media yields aflagellate Salmonella enterica serovar Typhimurium

Microbiology ◽  
2006 ◽  
Vol 152 (1) ◽  
pp. 23-28 ◽  
Author(s):  
Victoria L. Gray ◽  
Michael O'Reilly ◽  
Carsten T. Müller ◽  
Ian D. Watkins ◽  
David Lloyd
Keyword(s):  
Salmonella Enterica ◽  
Culture Media ◽  
Growth Media ◽  
Carbohydrate Source ◽  
Serovar Typhimurium ◽  
Peptone Water ◽  
Flagellar Filament ◽  
Morphological Differences ◽  
Tyrosine Concentration ◽  
Tyrosine Content

Identification of Salmonella serotypes is based on flagellar and somatic antigens. The absence of flagella may consequently affect complete identification of the serotype; here it is shown that Salmonella enterica serovar Typhimurium exhibits morphological differences dependent on the peptone constituents of the culture medium. Aflagellate salmonella were produced in certain media where the nutritional ingredient was casein-based peptone or gelatin-based peptone; in gelatin-based peptone, aggregates of salmonella were observed. However, in media containing soy-based peptone as the primary nutrient, salmonella displayed a normal flagellated morphology. Transfer of aflagellate salmonella from nutritionally poor media, with casein- or gelatin-based peptone, into rich nutrient broth allowed flagella synthesis, indicating that the aflagellate form is still able to produce flagella. Amino acid sequencing of the peptones producing aflagellate organisms showed a relatively low tyrosine concentration: only 0·03±0·01 g l−1 for gelatin-based buffered peptone water, compared to 0·21±0·01 for soy-based buffered peptone water. Tyrosine is essential for flagellin, which is the subunit of the salmonella flagellar filament. The addition of 200 μM tyrosine to casein-based peptone media produced flagellate salmonella; 2 mM glucose was needed in addition to tyrosine to achieve a similar morphology in gelatin-based media. Therefore, culture media containing less than 1·20 g tyrosine l−1, and of limited carbohydrate source, when used for serological testing of clinical isolates, may result in an incomplete serological identification.

scholarly journals Curcumin Reduces the Motility of Salmonella enterica Serovar Typhimurium by Binding to the Flagella, Thereby Leading to Flagellar Fragility and Shedding

2016 ◽  
Vol 198 (13) ◽  
pp. 1798-1811 ◽  
Author(s):  
Sandhya Amol Marathe ◽  
Arjun Balakrishnan ◽  
Vidya Devi Negi ◽  
Deepika Sakorey ◽  
Nagasuma Chandra ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Binding Assay ◽  
Protein A ◽  
Intestinal Barrier ◽  
Site Directed Mutagenesis ◽  
Content Type ◽  
Serovar Typhimurium ◽  
Flagellar Filament ◽  
Fluorescence Binding ◽  
Fluorescence Binding Assay

ABSTRACTOne of the important virulence properties of the pathogen is its ability to travel to a favorable environment, cross the viscous mucus barrier (intestinal barrier for enteric pathogens), and reach the epithelia to initiate pathogenesis with the help of an appendage, like flagella. Nonetheless, flagella can act as an “Achilles heel,” revealing the pathogen's presence to the host through the stimulation of innate and adaptive immune responses. We assessed whether curcumin, a dietary polyphenol, could alter the motility ofSalmonella, a foodborne pathogen. It reduced the motility ofSalmonella entericaserovar Typhimurium by shortening the length of the flagellar filament (from ∼8 μm to ∼5 μm) and decreasing its density (4 or 5 flagella/bacterium instead of 8 or 9 flagella/bacterium). Upon curcumin treatment, the percentage of flagellated bacteria declined from ∼84% to 59%. However, no change was detected in the expression of the flagellin gene and protein. A fluorescence binding assay demonstrated binding of curcumin to the flagellar filament. This might make the filament fragile, breaking it into smaller fragments. Computational analysis predicted the binding of curcumin, its analogues, and its degraded products to a flagellin molecule at an interface between domains D1 and D2. Site-directed mutagenesis and a fluorescence binding assay confirmed the binding of curcumin to flagellin at residues ASN120, ASP123, ASN163, SER164, ASN173, and GLN175.IMPORTANCEThis work, to our knowledge the first report of its kind, examines how curcumin targets flagellar density and affects the pathogenesis of bacteria. We found that curcumin does not affect any of the flagellar synthesis genes. Instead, it binds to the flagellum and makes it fragile. It increases the torsional stress on the flagellar filament that then breaks, leaving fewer flagella around the bacteria. Flagella, which are crucial ligands for Toll-like receptor 5, are some of the most important appendages ofSalmonella. Curcumin is an important component of turmeric, which is a major spice used in Asian cooking. The loss of flagella can, in turn, change the pathogenesis of bacteria, making them more robust and fit in the host.

scholarly journals Effect of Electropermeabilization by Ohmic Heating for Inactivation of Escherichia coli O157:H7, Salmonella enterica Serovar Typhimurium, and Listeria monocytogenes in Buffered Peptone Water and Apple Juice

2013 ◽  
Vol 79 (23) ◽  
pp. 7122-7129 ◽  
Author(s):  
Il-Kyu Park ◽  
Dong-Hyun Kang
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Electric Field ◽  
Salmonella Enterica ◽  
Apple Juice ◽  
Ohmic Heating ◽  
Conventional Heating ◽  
Content Type ◽  
Serovar Typhimurium ◽  
Peptone Water

ABSTRACTThe effect of electric field-induced ohmic heating for inactivation ofEscherichia coliO157:H7,Salmonella entericaserovar Typhimurium, andListeria monocytogenesin buffered peptone water (BPW) (pH 7.2) and apple juice (pH 3.5; 11.8 °Brix) was investigated in this study. BPW and apple juice were treated at different temperatures (55°C, 58°C, and 60°C) and for different times (0, 10, 20, 25, and 30 s) by ohmic heating compared with conventional heating. The electric field strength was fixed at 30 V/cm and 60 V/cm for BPW and apple juice, respectively. Bacterial reduction resulting from ohmic heating was significantly different (P< 0.05) from that resulting from conventional heating at 58°C and 60°C in BPW and at 55°C, 58°C, and 60°C in apple juice for intervals of 0, 10, 20, 25, and 30 s. These results show that electric field-induced ohmic heating led to additional bacterial inactivation at sublethal temperatures. Transmission electron microscopy (TEM) observations and the propidium iodide (PI) uptake test were conducted after treatment at 60°C for 0, 10, 20, 25 and 30 s in BPW to observe the effects on cell permeability due to electroporation-caused cell damage. PI values when ohmic and conventional heating were compared were significantly different (P< 0.05), and these differences increased with increasing levels of inactivation of three food-borne pathogens. These results demonstrate that ohmic heating can more effectively reduce bacterial populations at reduced temperatures and shorter time intervals, especially in acidic fruit juices such as apple juice. Therefore, loss of quality can be minimized in a pasteurization process incorporating ohmic heating.

scholarly journals Identification of Bacterial Species That Can Utilize Fructose-Asparagine

2017 ◽  
Vol 84 (5) ◽  
Author(s):  
Anice Sabag-Daigle ◽  
Jikang Wu ◽  
Mikayla A. Borton ◽  
Anindita Sengupta ◽  
Venkat Gopalan ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Culture Media ◽  
Bacterial Species ◽  
Klebsiella Oxytoca ◽  
Foodborne Pathogen ◽  
Toxic Metabolite ◽  
Toxicity Assay ◽  
Content Type ◽  
Serovar Typhimurium ◽  
Utilization Pathway

ABSTRACTSalmonella entericaserovar Typhimurium is the only organism demonstrated to utilize fructose-asparagine (F-Asn) as a source of carbon and nitrogen. In this report, we first used a bioinformatics approach to identify other microorganisms that encode homologs of theSalmonellaF-Asn utilization enzymes FraB (deglycase), FraD (kinase), and FraE (asparaginase). These candidate organisms were then tested with up to four different methods to confirm their ability to utilize F-Asn. The easiest and most broadly applicable method utilized a biological toxicity assay, which is based on the observation that F-Asn is toxic to aSalmonella fraBmutant. Candidate organisms were grown in a rich medium containing F-Asn, and depletion of F-Asn from the medium was inferred by the growth of aSalmonella fraBmutant in that same medium. For select organisms, the toxicity assay was cross-validated by direct mass spectrometry-aided measurement of F-Asn in the spent-culture media and through demonstration of FraB and FraD enzyme activity in cellular extracts. For prototrophs, F-Asn utilization was additionally confirmed by growth in a minimal medium containing F-Asn as the sole carbon source. Collectively, these studies established thatClostridiumbolteae,Clostridium acetobutylicum, andClostridium clostridioformecan utilize F-Asn, butClostridium difficilecannot;Klebsiella oxytocaand someKlebsiella pneumoniaesubspecies can utilize F-Asn; and someCitrobacter rodentiumandCitrobacter freundiistrains can also utilize F-Asn. WithinSalmonella enterica, the host-adapted serovars Typhi and Paratyphi A have lost the ability to utilize F-Asn.IMPORTANCEFructose-asparagine (F-Asn) is a precursor to acrylamide that is found in human foods, and it is also a nutrient source forSalmonella enterica, a foodborne pathogen. Here, we determined that among the normal intestinal microbiota, there are species ofClostridiumthat encode the enzymes required for F-Asn utilization. Using complementary experimental approaches, we have confirmed that three members ofClostridium, two members ofKlebsiella, and two members ofCitrobactercan indeed utilize F-Asn. TheClostridiumspp. likely compete withSalmonellafor F-Asn in the gut and contribute to competitive exclusion. FraB, one of the enzymes in the F-Asn utilization pathway, is a potential drug target because inhibition of this enzyme leads to the accumulation of a toxic metabolite that inhibits the growth ofSalmonellaspecies. This study identifies the potential off-target organisms that need to be considered when developing therapeutics directed at FraB.

scholarly journals The ClpXP ATP-Dependent Protease Regulates Flagellum Synthesis in Salmonella enterica Serovar Typhimurium

2002 ◽  
Vol 184 (3) ◽  
pp. 645-653 ◽  
Author(s):  
Toshifumi Tomoyasu ◽  
Tomiko Ohkishi ◽  
Yoshifumi Ukyo ◽  
Akane Tokumitsu ◽  
Akiko Takaya ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Proteome Analysis ◽  
Fourfold Increase ◽  
Master Regulators ◽  
Serovar Typhimurium ◽  
Flagellar Filament ◽  
Flagellar Regulon ◽  
Flagellar Proteins

ABSTRACT The ClpXP protease is a member of the ATP-dependent protease family and plays a dynamic role in the control of availability of regulatory proteins and the breakdown of abnormal and misfolded proteins. The proteolytic activity is rendered by the ClpP component, while the substrate specificity is determined by the ClpX component that has ATPase activity. We describe here a new role of the ClpXP protease in Salmonella enterica serovar Typhimurium in which ClpXP is involved in the regulation of flagellum synthesis. Cells deleted for ClpXP show “hyperflagellate phenotype,” exhibit overproduction of the flagellar protein, and show a fourfold increase in the rate of transcription of the fliC encoding flagellar filament. The assay for promoter activity of the genes responsible for expression of the fliC showed that the depletion of ClpXP results in dramatic enhancement of the expression of the fliA encoding sigma factor ς28, leaving the expression level of the flhD master operon lying at the top of the transcription hierarchy of flagellar regulon almost normal. These results suggest that the ClpXP may be responsible for repressing the expression of flagellar regulon through the control of the FlhD/FlhC master regulators at the posttranscriptional and/or posttranslational levels. Proteome analysis of proteins secreted from the mutant cells deficient for flhDC and clpXP genes demonstrated that the ΔflhD mutation abolished the enhanced effect by ΔclpXP mutation on the production of flagellar proteins, suggesting that the ClpXP possibly defines a regulatory pathway affecting the expression of flagellar regulon that is dependent on FlhD/FlhC master regulators.

scholarly journals Sensitivity of enrichment-PCR method for Salmonella enterica serovar Typhimurium and Salmonella enterica serovar Enteritidis analysis in chicken carcasses

Food Research ◽  
2021 ◽  
Vol 5 (2) ◽  
pp. 54-61
Author(s):  
H.A. Wulan ◽  
Nurjanah S. ◽  
W.P. Rahayu
Keyword(s):  
Salmonella Enterica ◽  
Pathogenic Bacteria ◽  
Target Genes ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Salmonella Enterica Serovar Enteritidis ◽  
Salmonella Spp ◽  
High Prevalence ◽  
Serovar Typhimurium ◽  
Peptone Water ◽  
Pcr Method

Salmonella spp. is Gram negative-pathogenic bacteria that usually found as a contaminant in chicken carcasses. This study was aimed to increase the sensitivity of PCR enrichment step and apply the enrichment-PCR combination to detect Salmonella in chicken carcasses. In this study were used Salmonella enterica serovar Hadar, Salmonella enterica serovar Typhimurium and Salmonella enterica serovar Enteritidis with the target genes were invA, STM4497, and respectively. A total of 25 g of the chicken carcasses were artificially contaminated by approximately 0.96 and 3.33 MPN/mL for each serovar separately. Samples were incubated in pre-enrichment and enrichment media for 8 hrs prior to the DNA extraction. The pre-enrichment and enrichment media was Buffered Peptone Water and Rappaport-Vassiliadis-soya. The result showed that the target genes of S. enterica ser. Hadar, S. enterica ser. Typhimurium and S. enterica ser. Enteritidis were detected in chicken carcasses, indicated by the presence of DNA band with the size was 429 bp, 311 bp and 135 bp respectively. These result in line with analysis using ISO method and BLAST-comparison analysis of DNA amplicon sequences with GenBank references. Application of this method for Salmonella detection in chicken carcasses sold in the traditional market showed a higher prevalence than the previous result without enrichment. All samples (n = 100) from unsanitary practice sellers were positively contaminated by Salmonella spp. and also high prevalence for S. enterica ser. Typhimurium and S. enterica ser. Enteritidis. It can be concluded that enrichment is an important step to increase the sensitivity detection of PCR method.

scholarly journals Genomic population structure associated with repeated escape of Salmonella enterica ATCC14028s from the laboratory into nature

PLoS Genetics ◽  
2021 ◽  
Vol 17 (9) ◽  
pp. e1009820
Author(s):  
Mark Achtman ◽  
Frederik Van den Broeck ◽  
Kerry K. Cooper ◽  
Philippe Lemey ◽  
Craig T. Parker ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Laboratory Strain ◽  
Core Gene ◽  
Growth Media ◽  
Culture Collections ◽  
Limited Life ◽  
Serovar Typhimurium ◽  
Natural Isolates ◽  
History Of ◽  
Extinction Events

Salmonella enterica serovar Typhimurium strain ATCC14028s is commercially available from multiple national type culture collections, and has been widely used since 1960 for quality control of growth media and experiments on fitness (“laboratory evolution”). ATCC14028s has been implicated in multiple cross-contaminations in the laboratory, and has also caused multiple laboratory infections and one known attempt at bioterrorism. According to hierarchical clustering of 3002 core gene sequences, ATCC14028s belongs to HierCC cluster HC20_373 in which most internal branch lengths are only one to three SNPs long. Many natural Typhimurium isolates from humans, domesticated animals and the environment also belong to HC20_373, and their core genomes are almost indistinguishable from those of laboratory strains. These natural isolates have infected humans in Ireland and Taiwan for decades, and are common in the British Isles as well as the Americas. The isolation history of some of the natural isolates confirms the conclusion that they do not represent recent contamination by the laboratory strain, and 10% carry plasmids or bacteriophages which have been acquired in nature by HGT from unrelated bacteria. We propose that ATCC14028s has repeatedly escaped from the laboratory environment into nature via laboratory accidents or infections, but the escaped micro-lineages have only a limited life span. As a result, there is a genetic gap separating HC20_373 from its closest natural relatives due to a divergence between them in the late 19th century followed by repeated extinction events of escaped HC20_373.

scholarly journals Structural and Functional Comparison of Salmonella Flagellar Filaments Composed of FljB and FliC

Biomolecules ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 246 ◽  
Author(s):  
Tomoko Yamaguchi ◽  
Shoko Toma ◽  
Naoya Terahara ◽  
Tomoko Miyata ◽  
Masamichi Ashihara ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
High Viscosity ◽  
Filament Formation ◽  
Electron Cryomicroscopy ◽  
Bacterial Flagellum ◽  
Serovar Typhimurium ◽  
Flagellar Filament ◽  
Position And Orientation ◽  
Rotary Motor

The bacterial flagellum is a motility organelle consisting of a long helical filament as a propeller and a rotary motor that drives rapid filament rotation to produce thrust. Salmonella enterica serovar Typhimurium has two genes of flagellin, fljB and fliC, for flagellar filament formation and autonomously switches their expression at a frequency of 10−3–10−4 per cell per generation. We report here differences in their structures and motility functions under high-viscosity conditions. A Salmonella strain expressing FljB showed a higher motility than one expressing FliC under high viscosity. To examine the reasons for this motility difference, we carried out structural analyses of the FljB filament by electron cryomicroscopy and found that the structure was nearly identical to that of the FliC filament except for the position and orientation of the outermost domain D3 of flagellin. The density of domain D3 was much lower in FljB than FliC, suggesting that domain D3 of FljB is more flexible and mobile than that of FliC. These differences suggest that domain D3 plays an important role not only in changing antigenicity of the filament but also in optimizing motility function of the filament as a propeller under different conditions.

scholarly journals Resuscitation by Ferrioxamine E of StressedSalmonella enterica Serovar Typhimurium from Soil and Water Microcosms

2000 ◽  
Vol 66 (9) ◽  
pp. 4128-4130 ◽  
Author(s):  
R. Reissbrodt ◽  
H. Heier ◽  
H. Tsch�pe ◽  
R. A. Kingsley ◽  
P. H. Williams
Keyword(s):  
Salmonella Enterica ◽  
Serovar Typhimurium ◽  
Peptone Water ◽  
Soil And Water

ABSTRACT Storage of Salmonella enterica serovar Typhimurium strains in soil and water microcosms resulted in loss of culturability on standard plating media. Prior incubation in buffered peptone water supplemented with ferrioxamine E markedly extended the time that bacteria were recoverable by plating, except in the case of mutants deficient in ferrioxamine E uptake.

scholarly journals Salmonella enterica Serovar Typhimurium Infection of Dendritic Cells Leads to Functionally Increased Expression of the Macrophage-Derived Chemokine

2005 ◽  
Vol 73 (3) ◽  
pp. 1714-1722 ◽  
Author(s):  
Guo Fu ◽  
Odilia L. C. Wijburg ◽  
Paul U. Cameron ◽  
Jason D. Price ◽  
Richard A Strugnell
Keyword(s):  
Dendritic Cells ◽  
T Cell ◽  
Salmonella Enterica ◽  
Fluorescent Protein ◽  
Culture Media ◽  
Expression Patterns ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serovar Typhimurium

ABSTRACT Gene expression in murine dendritic cells (DCs) infected with green fluorescent protein-expressing Salmonella enterica serovar Typhimurium BRD509 was studied by mRNA differential display. Infected DCs were sorted from uninfected cells by flow cytometry. The mRNA expression patterns of infected and uninfected cells revealed a number of differentially expressed transcripts, which included the macrophage-derived chemokine (MDC). Up-regulation of MDC transcription in infected DCs was confirmed by Northern blotting, and the kinetics of MDC expression was examined by real-time reverse transcription-PCR, with which 31- and 150-fold increases were detected at 2 and 6 h postinfection, respectively. The increased release by DCs of MDC into culture media was detected by an enzyme-linked immunosorbent assay. The biological activity of MDC was investigated in in vitro and in vivo assays. In vitro, supernatants from S. enterica serovar Typhimurium-infected DCs were chemoattractive to T cells, and neutralization of MDC in these supernatants inhibited T-cell migration. Passive transfer of anti-MDC antibody to mice infected with BRD509 revealed that neither growth of the bacterium nor resistance of the mice to reinfection was affected and that in vivo inhibition of MDC did not affect T-cell responses, as measured by the gamma interferon ELISPOT method 3 days after challenge infection.

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