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BMC Microbiology Mar 2020Vibrio vulnificus hemolysin (VVH) is a pore-forming toxin secreted by Vibrio vulnificus. Cellular cholesterol was believed to be the receptor for VVH, because...
BACKGROUND
Vibrio vulnificus hemolysin (VVH) is a pore-forming toxin secreted by Vibrio vulnificus. Cellular cholesterol was believed to be the receptor for VVH, because cholesterol could bind to VVH and preincubation with cholesterol inhibited cytotoxicity. It has been reported that specific glycans such as N-acetyl-D-galactosamine and N-acetyl-D-lactosamine bind to VVH, however, it has not been known whether these glycans could inhibit the cytotoxicity of VVH without oligomer formation. Thus, to date, binding mechanisms of VVH to cellular membrane, including specific receptors have not been elucidated.
RESULTS
We show here that VVH associates with ganglioside GM1a, Fucosyl-GM1, GD1a, GT1c, and GD1b by glycan array. Among them, GM1a could pulldown VVH. Moreover, the GD1a inhibited the cytotoxicity of VVH without the formation of oligomers.
CONCLUSION
This is the first report of a molecule able to inhibit the binding of VVH to target cells without oligomerization of VVH.
Topics: Animals; Bacterial Proteins; Binding Sites; CHO Cells; Cell Membrane; Cholesterol; Cricetulus; Gangliosides; Glycomics; Hemolysin Proteins; Microarray Analysis; Protein Binding; Protein Conformation; Protein Multimerization; Vibrio vulnificus
PubMed: 32228455
DOI: 10.1186/s12866-020-01755-1 -
Microorganisms Apr 2024Bacteria in the genus are ubiquitous in estuarine and coastal waters. Some species (including and are known human pathogens causing ailments like cholera, diarrhea,...
Bacteria in the genus are ubiquitous in estuarine and coastal waters. Some species (including and are known human pathogens causing ailments like cholera, diarrhea, or septicemia. Notably, can also cause a severe systemic infection (known as vibriosis) in eels raised in aquaculture facilities. Water samples were periodically collected from the estuary of the Asahi River, located in the southern part of Okayama City, Japan. These samples were directly plated onto CHROMagar Vibrio plates, and colonies displaying turquoise-blue coloration were selected. Thereafter, polymerase chain reaction was used to identify and . A total of 30 strains and 194 strains were isolated during the warm season when the water temperature (WT) was higher than 20 °C. Concurrently, an increase in coliforms was observed during this period. Notably, has two genotypes, designated as genotype 1 and genotype 2. Genotype 1 is pathogenic to humans, while genotype 2 is pathogenic to both humans and eels. The loop-mediated isothermal amplification method was developed to rapidly determine genotypes at a low cost. Of the 194 strains isolated, 80 (41.2%) were identified as genotype 1 strains. Among the 41 strains isolated when the WTs were higher than 28 °C, 25 strains (61.0%) belonged to genotype 1. In contrast, of the 32 strains isolated when the WTs were lower than 24 °C, 27 strains (84.4%) belonged to genotype 2. These results suggest that the distribution of the two genotypes was influenced by WT.
PubMed: 38792707
DOI: 10.3390/microorganisms12050877 -
Biomedical and Environmental Sciences :... Feb 2023This study investigated how the natural phytophenol and potent SIRT1 activator resveratrol (RSV) regulate necroptosis during induced sepsis and the potential mechanism.
OBJECTIVE
This study investigated how the natural phytophenol and potent SIRT1 activator resveratrol (RSV) regulate necroptosis during induced sepsis and the potential mechanism.
METHODS
The effect of RSV on cytolysin (VVC)-induced necroptosis was analyzed using CCK-8 and Western blot assays. Enzyme-linked immunosorbent assays and quantitative real-time polymerase chain reaction, western blot, and immunohistochemistry and survival analyses were performed to elucidate the effect and mechanism of RSV on necroptosis in a -induced sepsis mouse model.
RESULTS
RSV relieved necroptosis induced by VVC in RAW264.7 and MLE12 cells. RSV also inhibited the inflammatory response, had a protective effect on histopathological changes, and reduced the expression level of the necroptosis indicator pMLKL in peritoneal macrophages, lung, spleen, and liver tissues of -induced septic mice . Pretreatment with RSV downregulated the mRNA of the necroptosis indicator and protein expression in peritoneal macrophages and tissues of -induced septic mice. RSV also improved the survival of -induced septic mice.
CONCLUSION
Our findings collectively demonstrate that RSV prevented -induced sepsis by attenuating necroptosis, highlighting its potency in the clinical management of -induced sepsis.
Topics: Animals; Mice; Necroptosis; Resveratrol; Vibrio vulnificus; Sepsis; Blotting, Western
PubMed: 36861192
DOI: 10.3967/bes2023.017 -
BMC Microbiology Aug 2022Vibrio vulnificus is a pathogenic bacterium that causes disease in marine fish, affecting fish farming and human health worldwide. In May 2021, in the Bohai Bay region,...
Vibrio vulnificus is a pathogenic bacterium that causes disease in marine fish, affecting fish farming and human health worldwide. In May 2021, in the Bohai Bay region, a disease broke out in commercially farmed pearl gentian grouper (♀Epinephelus fuscoguttatus × ♂Epinephelus lanceolatus), causing huge economic losses. The diseased fish had skin lesions, water accumulation in their abdomens, and showed tissue and organ damage. V. vulnificus biotype 2 has been reported in eels and other marine fish, but it is less reported in pearl gentian grouper. In this study, the pathogenic strain isolated from diseased fish was identified as V. vulnificus EPL 0201 biotype 2 on the basis of physiological and biochemical characteristics and the results of 16S rRNA gene and gyrB sequencing, virulence gene detection, and recursive infection experiments. To gain a comprehensive understanding of the pathogenicity and drug resistance of this strain, whole-genome sequencing was performed. Whole-genome analysis showed that the gene map of this strain was complete. The Virulence Factor Database annotation results showed that this strain had the key virulence factor genes vvhA and rtxA, which cause host disease. In addition, this strain had genes conferring resistance against cephalosporins, aminoglycosides, tetracyclines, and sulfonamides. Antimicrobial susceptibility testing confirmed the presence of these resistance genes identified in the genome. The results of this study show that V. vulnificus EPL 0201 biotype 2 is a multi-drug resistant strain with high pathogenicity.
Topics: Animals; Anti-Bacterial Agents; Bass; Eels; Humans; RNA, Ribosomal, 16S; Vibrio; Vibrio Infections; Vibrio vulnificus; Virulence Factors
PubMed: 35974308
DOI: 10.1186/s12866-022-02610-1 -
NPJ Vaccines Sep 2023Flagellin, the TLR5 agonist, shows potent adjuvant activities in diverse vaccines and immunotherapies. Vibrio vulnificus flagellin B expressed in eukaryotic cells...
Flagellin, the TLR5 agonist, shows potent adjuvant activities in diverse vaccines and immunotherapies. Vibrio vulnificus flagellin B expressed in eukaryotic cells (eFlaB) could not stimulate TLR5 signaling. Enzymatic deglycosylation restored eFlaB's TLR5 stimulating functionality, suggesting that glycosylation interferes with eFlaB binding to TLR5. Site-directed mutagenesis of N-glycosylation residues restored TLR5 stimulation and adjuvanticity. Collectively, deglycosylated eFlaB may provide a built-in adjuvant platform for eukaryotic-expressed antigens and nucleic acid vaccines.
PubMed: 37752138
DOI: 10.1038/s41541-023-00738-3 -
Foods (Basel, Switzerland) Dec 2022Human-pathogenic bacteria are acquired by oysters through filtering seawater, however, the relationships between levels of these bacteria in measured in oysters and...
Human-pathogenic bacteria are acquired by oysters through filtering seawater, however, the relationships between levels of these bacteria in measured in oysters and overlying waters are inconsistent across regions. The reasons for these discrepancies are unclear hindering our ability to assess if -or when- seawater samples can be used as a proxy for oysters to assess risk. We investigated whether concentrations of total and human pathogenic ( and genes) and (, and genes) measured in seawater reflect concentrations of these bacteria in oysters ( cultured within the US lower Chesapeake Bay region. We measured spp. concentrations using an MPN-qPCR approach and analyzed the data using structural equation modeling (SEM). We found seawater concentrations of these bacteria to predictably respond to temperature and salinity over chlorophyll , pheophytin or turbidity. We also inferred from the SEM results that concentrations in seawater strongly predict their respective concentrations in oysters. We hypothesize that such seawater-oyster coupling can be observed in regions of low tidal range. Due to the ease of sampling and processing of seawater samples compared to oyster samples, we suggest that under low tidal range conditions, seawater samples can foster increased spatial and temporal coverage and complement data associated with oyster samples.
PubMed: 36553807
DOI: 10.3390/foods11244065 -
Computational and Structural... 2021We previously demonstrated that a marine bacterial pathogen isolated from sea foods modulated gene expression levels and defense responses of a land plant . Although...
We previously demonstrated that a marine bacterial pathogen isolated from sea foods modulated gene expression levels and defense responses of a land plant . Although the interaction between and was verified under artificial and greenhouse conditions, the simultaneous changes in host and pathogen transcriptomes remained obscure. In this study, we simultaneously analyzed the transcriptome of MO6-24/O and by dual RNA-sequencing analysis. Disease symptoms appeared at 5 and 7 days post-inoculation and post-infiltration , respectively. A total of 31, 128, 303, 219, and 130 differentially expressed genes (DEGs) were identified in MO6-24/O at 3, 6, 12, 24, and 48 h post-infiltration. Out of these, 14 genes involved in the virulence and pathogenicity of MO6 were characterized. These genes were clustered into six categories, including adherence, antiphagocytosis, chemotaxis and motility, iron uptake, toxin and secretion system. In plant side, the bacterium DEGs potentially played a pivotal role in activating pattern recognition receptors (PRRs)-mediated defense responses. genes related to PRRs, reactive oxygen species burst, mitogen-activated protein kinase cascade induction, salicylic acid, jasmonic acid, ethylene, abscisic acid, auxin, gibberellin, and cytokinin were highly induced by MO6-24/O challenge. Taken together, our results indicate that the sophisticated communication between a marine bacterial pathogen and occurs. It is the first report demonstration that actively modulates its virulence factors and potential host immune regulator in a land plant species.
PubMed: 33995904
DOI: 10.1016/j.csbj.2021.04.008 -
Frontiers in Cellular and Infection... 2021RtxA1 is a major cytotoxin of () causing fatal septicemia and necrotic wound infections. Our previous work has shown that RpoS regulates the expression and secretion of...
RtxA1 is a major cytotoxin of () causing fatal septicemia and necrotic wound infections. Our previous work has shown that RpoS regulates the expression and secretion of RtxA1 toxin. This study was conducted to further investigate the potential mechanisms of RpoS on RtxA1 secretion. First, TolCV1 and TolCV2 proteins, two TolC homologs, were measured at various time points by Western blotting. The expression of TolCV1 was increased time-dependently, whereas that of TolCV2 was decreased. Expression of both TolCV1 and TolCV2 was significantly downregulated in an deletion mutation. Subsequently, we explored the roles of TolCV1 and TolCV2 in pathogenesis. Western blot analysis showed that RtxA1 toxin was exported by TolCV1, not TolCV2, which was consistent with the cytotoxicity results. Furthermore, the expression of TolCV1 and TolCV2 was increased after treatment of the host signal bile salt and the growth of mutant was totally abolished in the presence of bile salt. A mutation resulted in significant reduction of induced-virulence in mice. Taken together, TolCV1 plays key roles in RtxA1 secretion, bile salt resistance, and mice lethality of , suggesting that TolCV1 could be an attractive target for the design of new medicines to treat infections.
Topics: Animals; Bacterial Proteins; Escherichia coli; Mice; Vibrio Infections; Vibrio vulnificus; Virulence
PubMed: 33996641
DOI: 10.3389/fcimb.2021.673222 -
Frontiers in Microbiology 2021is an important zoonotic and aquatic pathogen and can cause vibriosis in humans and aquatic animals (especially farmed fish and shrimp species). Rapid and sensitive...
is an important zoonotic and aquatic pathogen and can cause vibriosis in humans and aquatic animals (especially farmed fish and shrimp species). Rapid and sensitive detection methods for are still required to diagnose human vibriosis early and reduce aquaculture losses. Herein, we developed a rapid and sensitive diagnostic method comprising a recombinase-aided amplification (RAA) assay and the CRISPR/Cas12a system (named RAA-CRISPR/Cas12a) to detect . The RAA-CRISPR/Cas12a method allows rapid and sensitive detection of in 40 min without a sophisticated instrument, and the limit of detection is two copies of genomic DNA per reaction. Meanwhile, the method shows satisfactory specificity toward non-target bacteria and high accuracy in the spiked blood, stool, and shrimp samples. Therefore, our proposed rapid and sensitive detection method, RAA-CRISPR/Cas12a, has great potential for early diagnosis of human vibriosis and on-site detection in aquaculture and food safety control.
PubMed: 34745075
DOI: 10.3389/fmicb.2021.767315 -
Frontiers in Microbiology 2022species are disseminated broadly in the marine environment. Some of them can cause severe gastroenteritis by contaminating seafood and drinking water, such as , and .... (Review)
Review
species are disseminated broadly in the marine environment. Some of them can cause severe gastroenteritis by contaminating seafood and drinking water, such as , and . However, their pathogenic mechanism still needs to be revealed to prevent and reduce morbidity. This review comprehensively introduces and discusses the common pathogenic process of including adhesion, cell colonization and proliferation, and resistance to host immunity. usually produces pathogenic factors including hemolysin, type-III secretion system, and adhesion proteins. Quorum sensing, a cell molecular communication system between the bacterial cells, plays an important role in intestinal invasion and colonization. The human immune system can limit the virulence of or even kill the bacteria through different responses. The intestinal microbiota is a key component of the immune system, but information on its effects on physiological metabolism and pathogenicity of is seldom available. In this review, the effects of intestinal microorganisms and their metabolites on the invasion and colonization of common pathogenic and VBNC status cells are discussed, which is conducive to finding the next-generation prebiotics. The strategy of dietary intervention is discussed for food safety control. Finally, future perspectives are proposed to prevent infection in aquaculture.
PubMed: 36081796
DOI: 10.3389/fmicb.2022.947767