• Journal of Microbiology
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• v.45 no.4
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• pp.311-317
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• 2007

In this study, the effects of phosphate concentration and carbon source on the patterns of alkaline phosphatase (APase) and phospholipase (PLase) expression in Vibrio vulnificus ATCC 29307 were assessed under various conditions. The activities of these enzymes were repressed by excess phosphate (4 mM) in the culture medium, but this repression was reversed upon the onset of phosphate starvation in low phosphate defined medium (LPDM) containing 0.2 mM of phosphate at approximately the end of the exponential growth phase. The expressions of the two enzymes were also influenced by different carbon sources, including glucose, fructose, maltose, glycerol, and sodium acetate at different levels. The APase activity was derepressed most profoundly in LPDM containing fructose as a sole carbon source. However, the repression/derepression of the enzyme by phosphate was not observed in media containing glycerol or sodium acetate. In LPDM-glycerol or sodium acetate, the growth rate was quite low. The highest levels of PLase activity were detected in LPDM-sodium acetate, followed by LPDM-fructose. PLase was not fully repressed by high phosphate concentrations when sodium acetate was utilized as the sole carbon source. These results showed that multiple regulatory systems, including the phosphate regulon, may perform a function in the expression of both or either APase and PLC, in the broader context of the survival of V. vulnificus.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.6
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• pp.918-926
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• 2021

We isolated 28 Vibrio vulnificus strains from seawater and fisheries and investigated the positive rate of eight virulence genes. Additionally, we evaluated the susceptibility of these strains to 25 antimicrobials. The positive rates of fur, vvhA, tcp, rtxA, vcgC, viuB, vvp, and acfA were 100, 92.9, 92.9, 67.9, 64.3, 25.0, 14.3, and 7.1%, respectively. A disk diffusion susceptibility test revealed that, all the investigated strains had the highest resistance to amoxicillin and oxacillin, followed by that to streptomycin (96.4%), cefoxitin (92.9%), clindamycin (82.1%), amikacin (67.9%), vancomycin (46.4%), nalidixic acid (7.1%), penicillin G (7.1%), and ampicillin (3.6%). Moreover, they were susceptible to 10 other antimicrobials, including cefotaxime, chloramphenicol, erythromycin, gentamicin, and rifampicin. Notably, amoxicillin, oxacillin, and streptomycin had average minimum inhibitory concentrations of 132.6, 603.4, and 23.1 ㎍/mL against V. vulnificus, respectively. These observations provide new insights regarding the necessity for sanitation of commercial fisheries and can potentially, help reduce the risk posed by fisheries contaminated with bacteria resistant to antimicrobials.

• Journal of Environmental Health Sciences
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• v.44 no.2
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• pp.133-142
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• 2018

Objectives: The pathogenic Vibrios genus denotes halophilic bacteria that are distributed in aquatic environments, including both sea and freshwater. Vibrio cholerae, Vibrio vulnificus, and Vibrio parahaemolyticus are the most important species since they can be potent human pathogens and leading causes of septicemia, wound infections, and seafood borne gastroenteritis. The recent emergence of a potential pandemic clone, V. cholera serotype O1 and the cholera outbreak in South Korea in 2016 indicates the importance of consistent surveillance of pathogenic Vibrio genus within coastal areas. Methods: The present study was undertaken to determine where and how vibrios live in the aquatic environment adjacent to coastal areas of South Korea. For this survey, a total of 838 samples were obtained at 35 different sites in South Korean coastal areas during the period from January 2016 to December 2016. Pathogenic vibrios was determined using the real-time PCR method, and its clones were isolated using three selective plating media. We also monitored changes in seawater and atmospheric temperature, salinity, turbidity, and hydrogen ion concentration at the collection points. Results: The total isolation rates of V. vulnificus, V. cholera (non-pathogenic, non-O1, non-O139 serogroups), and V. parahaemolyticus from seawater specimens in 2016 were 14.2, 13.48, and 67.06%, respectively. Conclusions: The isolation rates of pathogenic vibrios genus showed a positive correlation with temperature of seawater and atmosphere but were negatively correlated with salinity and turbidity.

• Journal of environmental and Sanitary engineering
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• v.23 no.3
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• pp.31-38
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• 2008

This study was conducted to investigate the effects of environmental factor such as temperature, salinity, turbidity, pH and dissolved oxygen on the growth of Vibrio spp.. In this survey, total 56 seawater samples were obtained from 8 different sites of the Incheon coastal area during the periods from april 2008 to october 2008. Enumeration of Vibrio spp. was determined by using the most probable number(MPN) procedure. Isolation rates of V. parahaemolyticus, V. vulnificus, V. cholerae in all samples tested were 44.0%, 21.4% and 13.1%, respectively. The enumeration of Vibrio spp. was very low correlated with water temperature and pH and negatively correlated with salinity, dissolved oxygen and turbidity. We found salinity to be the parameter most highly correlated with the enumeration of Vibrio spp. The highest rate of antibiotic resistance of V.vulnificus and V.parahaemolyticus was Cefazolin(11.5%), Ampicillin(70.8%), respectively.

• Journal of Food Hygiene and Safety
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• v.31 no.1
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• pp.21-27
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• 2016

The objectives of this study are to produce monoclonal antibodies (MAbs) against Vibrio parahaemolyticus and to develop an immuno-selective filtration (ISF) method for the rapid and sensitive detection of V. parahaemolyticus. The characterization of the MAb produced from HKVP 4H9-9 hybridoma cell was validated by enzyme-linked immunosorbent assay (ELISA) and western blot. The produced MAb was specific to V. parahaemolyticus and showed weak cross-reaction to V. alginolyticus, V. vulnificus and Staphylococcus aureus. After optimization of the method, $5{\times}10^1cell/mL$ of V. parahaemolyticus in a pure culture could be detectable. Although weak cross-reactivity to V. vulnificus, V. alginolyticus and Staphylococcus aureus was observed, the ISF was confirmed to be highly specific to V. parahaemolyticus. Especially, the ISF showed the most sensitivity compared to the immunoassays currently reported is easier to perform and quicker than ID-ELISA.

• Molecules and Cells
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• v.40 no.4
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• pp.299-306
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• 2017

The transcriptional activator AphB has been implicated in acid resistance and pathogenesis in the food borne pathogens Vibrio vulnificus and Vibrio cholerae. To date, the full-length AphB crystal structure of V. cholerae has been determined and characterized by a tetrameric assembly of AphB consisting of a DNA binding domain and a regulatory domain (RD). Although acidic pH and low oxygen tension might be involved in the activation of AphB, it remains unknown which ligand or stimulus activates AphB at the molecular level. In this study, we determine the crystal structure of the AphB RD from V. vulnificus under aerobic conditions without modification at the conserved cysteine residue of the RD, even in the presence of the oxidizing agent cumene hydroperoxide. A cysteine to serine amino acid residue mutant RD protein further confirmed that the cysteine residue is not involved in sensing oxidative stress in vitro. Interestingly, an unidentified small molecule was observed in the inter-subdomain cavity in the RD when the crystal was incubated with cumene hydroperoxide molecules, suggesting a new ligand-binding site. In addition, we confirmed the role of AphB in acid tolerance by observing an aphB-dependent increase in cadC transcript level when V. vulnificus was exposed to acidic pH. Our study contributes to the understanding of the AphB molecular mechanism in the process of recognizing the host environment.

• Journal of Microbiology and Biotechnology
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• v.22 no.8
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• pp.1107-1112
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• 2012

Outbreaks of foodborne diseases associated with Vibrio species such as V. parahaemolyticus, V. vulnificus, and V. cholerae frequently occur in countries having a dietary habit of raw seafood consumption. For rapid identification of different Vibrio species involved in foodborne diseases, whole-cell protein pattern analysis for 13 type strains of 12 Vibrio species was performed using SDS-PAGE analysis. Pathogenic Vibrio species such as V. parahaemolyticus, V. vulnificus, V. cholerae, V. alginolyticus, V. fluvialis, and V. mimicus were included in the 12 Vibrio species used in this study. Each of the 12 Vibrio species showed clearly specific band patterns of its own. Two different strains of V. parahaemolyticus showed two different SDS-PAGE whole-cell protein patterns, giving the possibility of categorizing isolated strains in the same V. parahaemolyticus species into two subgroups. The 36 Vibrio isolates collected from sushi restaurants in Busan were all identified as V. parahaemolyticus by comparing their protein patterns with those of Vibrio type strains. The identified isolates were categorized into two different subgroups of V. parahaemolyticus. The whole-cell protein pattern analysis by SDS-PAGE can be used as a specific, rapid, and simple identification method for Vibrio spp. involved in foodborne diseases at the subspecies level.

• Journal of Microbiology and Biotechnology
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• v.18 no.1
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• pp.35-42
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• 2008

Vibrio vulnificus produces siderophores, low-molecular-weight iron-chelating compounds, to obtain iron under conditions of iron deprivation. To identify genes associated with the biosynthesis of siderophore in V. vulnificus MO6-24/O, we screened clones with mini-Tn5 random insertions for those showing decreased production of siderophore. Among 6,000 clones screened, nine such clones were selected. These clones contain the transposon inserted in VV2_0830 (GenBank accession number) that is a homolog of a nonribosomal peptide synthase (NRPS). There is an another NRPS module, VV2_0831, 49-bp upstream to VV2_0830. We named these two genes vvs (Vibrio vulnificus siderophore synthase) A and B, respectively. Mutation of either vvsA or vvsB showed a decreased production of siderophore. The expression of an NRPS-lux fusion was negatively modulated by the presence of iron, and the regulation was dependent on Fur (ferric uptake regulator). However, the expression of the NRPS genes was still not fully derepressed in the iron-rich condition, even in furnull mutant cells, suggesting that some other unknown factors are involved in the regulation of the genes. We also demonstrated that the NRPS genes are important for virulence of the pathogen in a mice model.

• Korean Journal of Agricultural Science
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• v.32 no.1
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• pp.71-80
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• 2005

Phytic acid chelates excellently the metallic ions and the positive ions, especially has high affinity with $Fe^{2+}$ and $Ca^{2+}$. Merits of phytic acid can be taked in easily, edibile and harmless to body, so it was investigated that phytic acid can be substituted for EDTA in this study. 1. The Intensificative effect of chelating agent and disinfective osmotic shock of Vibrio vulnificus The number of initial existent fungi measured $1.7{\times}10^6$. The percentages of the survival fungi against the osmotic shock by distillated water were calculated at 1 minute, 3 minute and 5 minute after inoculation. The percentages of the survival fungi in $Mg^{2+}$ were 92.5%, 91.8% and 79.8% at each time, the average percentage was 88%. Also the sudden extinction was observed around 1 minute after inoculation and the survival fungi were not observed from 3 through 5 minute in spite of repeated experimentation. 2. Influence of Vibrio vulnificus on the survival of the mice. The first mouse started to die in 180 minute after inoculation in case that the inoculating number was $2.3{\times}10^7cfu/ml$. All died within 4.5 hour. The average of survival time was 226 minute. The first mouse started to die in 228 minute after inoculation in case that the inoculating number was $0.8{\times}10^6cfu/ml$. All died within 5 hour. The average of survival time was 300 minute and the survival time was 1.3 times high. The tendencies of death in two cases were similar, but the fatal rate were largely dependent on inoculating number.

• Korean Journal of Microbiology
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• v.49 no.4
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• pp.383-390
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• 2013

Lateral gene transfer (LGT) of genes from other bacteria into Vibrio cholerae is expectable because of the pronounced natural competence of the bacterium. In this study, quantitative aspects of LGT among the three species of Vibrio pathogenic to humans were characterized. Genome sequences of V. cholerae N16961, V. parahaemolyticus RIMD2210633, V. vulnificus CMCP6, and Escherichia coli K12 substrain MG1655 were analyzed to determine orthologous quartets of protein coding genes present in all four genomes. Phylogenetic analyses on the quartets were conducted to resolve vertical versus lateral patterns of gene polymorphisms based on congruence versus incongruence of phylogenetic trees. About 70% of the quartets could be resolved as either cohesive topology (75%) or LGT tree topologies (25%). The amount of LGT genes in Vibrio spp. appeared to be abnormally high for a genus and comparable to those of families. Patched distributions of LGT from different donors were observed on a chromosome. In the small chromosome of V. cholerae, physical linkages among LGT loci spanned half the length of the chromosome. Either accumulative selection for the donor alleles in LGT or presence of large-scale LGT events was hypothesized. These findings warrant further studies on the nature of donor-specificity of LGT alleles and its influence on evolution of Vibrio virulence to humans.