Dataset Information

Identification and Characterization of als Genes Involved in D-Allose Metabolism in Lineage II Strain of Listeria monocytogenes.

ABSTRACT: Listeria monocytogenes, an important food-borne pathogen, causes listeriosis and is widely distributed in many different environments. In a previous study, we developed a novel enrichment broth containing D-allose that allows better isolation of L. monocytogenes from samples. However, the mechanism of D-allose utilization by L. monocytogenes remains unclear. In the present study, we determined the metabolism of D-allose in L. monocytogenes and found that lineage II strains of L. monocytogenes can utilize D-allose as the sole carbon source for growth, but lineage I and III strains cannot. Transcriptome analysis and sequence alignment identified six genes (lmo0734 to 0739) possibly related to D-allose metabolism that are only present in the genomes of lineage II strains. Recombinant strain ICDC-LM188 containing these genes showed utilization of D-allose by growth assays and Biolog phenotype microarrays. Moreover, lmo0734 to 0736 were verified to be essential for D-allose metabolism, lmo0737 and 0738 affected the growth rate of L. monocytogenes in D-allose medium, while lmo0739 was dispensable in the metabolism of D-allose in L. monocytogenes. This is the first study to identify the genes related to D-allose metabolism in L. monocytogenes, and their distribution in lineage II strains. Our study preliminarily determined the effects of these genes on the growth of L. monocytogenes, which will benefit the isolation and epidemiological research of L. monocytogenes.

SUBMITTER: Zhang L

PROVIDER: S-EPMC5893763 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Identification and Characterization of als Genes Involved in D-Allose Metabolism in Lineage II Strain of Listeria monocytogenes.

Zhang Lu L Wang Yan Y Liu Dongxin D Luo Lijuan L Wang Yi Y Ye Changyun C

Frontiers in microbiology 20180404

Listeria monocytogenes, an important food-borne pathogen, causes listeriosis and is widely distributed in many different environments. In a previous study, we developed a novel enrichment broth containing D-allose that allows better isolation of L. monocytogenes from samples. However, the mechanism of D-allose utilization by L. monocytogenes remains unclear. In the present study, we determined the metabolism of D-allose in L. monocytogenes and found that lineage II st ...[more]

PMID: 29670595

Similar Datasets

Project description:BACKGROUND:Listeria monocytogenes is a widespread foodborne pathogen that can cause listeriosis, a potentially fatal infection. L. monocytogenes is subdivided into four phylogenetic lineages, with the highest incidence of listeriosis occurring within lineage I followed by lineage II. Strains of L. monocytogenes differ in their phenotypic characteristics, including virulence. However, the genetic bases for these observed differences are not well understood, and current efforts to monitor L. monocytogenes in food consider all strains to be equally virulent. We use a comparative genomics approach to identify genes and single nucleotide polymorphisms (SNPs) in 174 clinical and food isolates of L. monocytogenes that potentially contribute to virulence or the capacity to adapt to food environments. RESULTS:No SNPs are significantly associated with food or clinical isolates. No genes are significantly associated with food or clinical isolates from lineage I, but eight genes consisting of multiple homologues are associated with lineage II food isolates. These include three genes which encode hypothetical proteins, the cadmium resistance genes cadA and cadC, the multi-drug resistance gene ebrB, a quaternary ammonium compound resistance gene qac, and a regulatory gene. All eight genes are plasmid-borne, and most closed L. monocytogenes plasmids carry at least five of the genes (24/27). In addition, plasmids are more frequently associated with lineage II food isolates than with lineage II clinical isolates. CONCLUSIONS:We identify eight genes that are significantly associated with food isolates in lineage II. Interestingly, the eight genes are virtually absent in lineage II outbreak isolates, are composed of homologues which show a nonrandom distribution among lineage I serotypes, and the sequences are highly conserved across 27 closed Listeria plasmids. The functions of these genes should be explored further and will contribute to our understanding of how L. monocytogenes adapts to the host and food environments. Moreover, these genes may also be useful as markers for risk assessment models of either pathogenicity or the ability to proliferate in food and the food processing environment.

Project description:BackgroundThe bacterium Listeria monocytogenes is a saprotroph as well as an opportunistic human foodborne pathogen, which has previously been shown to consist of at least two widespread lineages (termed lineages I and II) and an uncommon lineage (lineage III). While some L. monocytogenes strains show evidence for considerable diversification by homologous recombination, our understanding of the contribution of recombination to L. monocytogenes evolution is still limited. We therefore used STRUCTURE and ClonalFrame, two programs that model the effect of recombination, to make inferences about the population structure and different aspects of the recombination process in L. monocytogenes. Analyses were performed using sequences for seven loci (including the house-keeping genes gap, prs, purM and ribC, the stress response gene sigB, and the virulence genes actA and inlA) for 195 L. monocytogenes isolates.ResultsSequence analyses with ClonalFrame and the Sawyer's test showed that recombination is more prevalent in lineage II than lineage I and is most frequent in two house-keeping genes (ribC and purM) and the two virulence genes (actA and inlA). The relative occurrence of recombination versus point mutation is about six times higher in lineage II than in lineage I, which causes a higher genetic variability in lineage II. Unlike lineage I, lineage II represents a genetically heterogeneous population with a relatively high proportion (30% average) of genetic material imported from external sources. Phylograms, constructed with correcting for recombination, as well as Tajima's D data suggest that both lineages I and II have suffered a population bottleneck.ConclusionOur study shows that evolutionary lineages within a single bacterial species can differ considerably in the relative contributions of recombination to genetic diversification. Accounting for recombination in phylogenetic studies is critical, and new evolutionary models that account for the possibility of changes in the rate of recombination would be required. While previous studies suggested that only L. monocytogenes lineage I has experienced a recent bottleneck, our analyses clearly show that lineage II experienced a bottleneck at about the same time, which was subsequently obscured by abundant homologous recombination after the lineage II bottleneck. While lineage I and lineage II should be considered separate species from an evolutionary viewpoint, maintaining single species name may be warranted since both lineages cause the same type of human disease.

Project description:Listeria monocytogenes is able to efficiently utilize glycerol as a carbon source. In a defined minimal medium, the growth rate (during balanced growth) in the presence of glycerol is similar to that in the presence of glucose or cellobiose. Comparative transcriptome analyses of L. monocytogenes showed high-level transcriptional upregulation of the genes known to be involved in glycerol uptake and metabolism (glpFK and glpD) in the presence of glycerol (compared to that in the presence of glucose and/or cellobiose). Levels of expression of the genes encoding a second putative glycerol uptake facilitator (GlpF(2)) and a second putative glycerol kinase (GlpK(2)) were less enhanced under these conditions. GlpK(1) but not GlpK(2) was essential for glycerol catabolism in L. monocytogenes under extracellular conditions, while the loss of GlpK(1) affected replication in Caco-2 cells less than did the loss of GlpK(2) and GlpD. Additional genes whose transcription levels were higher in the presence of glycerol than in the presence of glucose and cellobiose included those for two dihydroxyacetone (Dha) kinases and many genes that are under carbon catabolite repression control. Transcriptional downregulation in the presence of glycerol (compared to those in the presence glucose and cellobiose) was observed for several genes and operons that are positively regulated by glucose, including genes involved in glycolysis, N metabolism, and the biosynthesis of branched-chain amino acids. The highest level of transcriptional upregulation was observed for all PrfA-dependent genes during early and late logarithmic growth in glycerol. Under these conditions, a low level of HPr-Ser-P and a high level of HPr-His-P were present in the cells, suggesting that all enzyme IIA (EIIA) (or EIIB) components of the phosphotransferase system (PTS) permeases expressed will be phosphorylated. These and other data suggest that the phosphorylation state of PTS permeases correlates with PrfA activity.

Project description:Listeria monocytogenes is a public health and food safety challenge due to its virulence and natural stress resistance phenotypes. The variable distribution of L. monocytogenes molecular subtypes with respect to food products and processing environments and among human and animal clinical listeriosis cases is observed. Sixty-two clinical and food-associated L. monocytogenes isolates were examined through phenome and genome analysis. Virulence assessed using a zebrafish infection model revealed serotype and genotype-specific differences in pathogenicity. Strains of genetic lineage I serotype 4b and multilocus sequence type clonal complexes CC1, CC2, CC4, and CC6 grew and survived better and were more virulent than serotype 1/2a and 1/2c lineage II, CC8, and CC9 strains. Hemolysis, phospholipase activity, and lysozyme tolerance profiles were associated with the differences observed in virulence. Osmotic stress resistance evaluation revealed serotype 4b lineage I CC2 and CC4 strains as more osmotolerant, whereas serotype 1/2c lineage II CC9 strains were more osmo-sensitive than others. Variable tolerance to the widely used quaternary ammonium compound benzalkonium chloride (BC) was observed. Some outbreak and sporadic clinical case associated strains demonstrated BC tolerance, which might have contributed to their survival and transition in the food-processing environment facilitating food product contamination and ultimately outbreaks or sporadic listeriosis cases. Genome comparison uncovered various moderate differences in virulence and stress associated genes between the strains indicating that these differences in addition to gene expression regulation variations might largely be responsible for the observed virulence and stress sensitivity phenotypic differences. Overall, our study uncovered strain and genotype-dependent variation in virulence and stress resilience among clinical and food-associated L. monocytogenes isolates with potential public health risk implications. The extensive genome and phenotypic data generated provide a basis for developing improved Listeria control strategies and policies.

Project description:BackgroundListeria monocytogenes is a common cause of bacterial meningitis. We developed an animal model of listerial meningitis.MethodsIn survival studies, C57BL/6 mice received intracisternal injections with different L. monocytogenes sequence type 1 (ST1) colony forming units per milliliter (CFU; n = 48, 105, 106, 107, 108, and 109 CFU/ml). Second, mice were inoculated with 108 CFU/ml ST1 and sacrificed at 6 h and 24 h (n = 12/group). Outcome parameters were clinical score, CFUs, cyto- and chemokine levels, and brain histopathology. Third, 84 mice were inoculated (109 CFU/ml ST1) to determine optimal antibiotic treatment with different doses of amoxicillin and gentamicin. Fourth, mice were inoculated with 109 CFU/ml ST1, treated with amoxicillin, and sacrificed at 16 h and 24 h (n = 12/group) for outcome assessment. Finally, time point experiments were repeated with ST6 (n = 24/group).ResultsMedian survival time for inoculation with 108 and 109 CFU/ml ST1 was 46 h and 40 h; lower doses of bacteria led to minimal clinical signs of disease. Brain levels of IL-6, IL-17A, and IFN-γ were elevated at 24 h, and IL-1β, IL-6, IL-10, IFN-γ, and TNF-α were elevated in blood at 6 h and 24 h. Histopathology showed increased meningeal infiltration, vascular inflammation of meningeal vessels, hemorrhages, and ventriculitis. In the treatment model, brain levels of IL-6 and IL-17A and blood levels of IL-6 and IFN-γ were elevated. Compared to ST6, infection with ST1 led initially to higher levels of IL-1β and TNF-α in blood and more profound neuropathological damage. At 16 h post inoculation, IL-1β, IL-10, and TNF-α in blood and IL-6, IL17A, TNF-α, and IFN-γ levels in brain were higher in ST1 compared to ST6 without differences in CFUs between STs. At 24 h, neuropathology score was higher in ST1 compared to ST6 (p = 0.002) infected mice.ConclusionsWe developed and validated a murine model of listerial meningitis. ST1-infected mice had a more severe inflammatory response and brain damage as compared to ST6-infected mice.

Dataset Information

Identification and Characterization of als Genes Involved in D-Allose Metabolism in Lineage II Strain of Listeria monocytogenes.

Publications

Identification and Characterization of <i>als</i> Genes Involved in D-Allose Metabolism in Lineage II Strain of <i>Listeria monocytogenes</i>.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets