• Journal of Microbiology
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• v.44 no.5
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• pp.537-547
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• 2006

This study was designed to determine whether or not Vibrio vulnificus metalloprotease VvpE can promote iron uptake via the proteolytic cleavage of human hemoglobin. We found that V. vulnificus utilized hemoglobin as an iron source more efficiently via the vulnibactin-mediated iron-uptake system than via the HupA-mediated iron-uptake system and, of the proteases produced by V. vulnificus, VvpE was found to be the only protease capable of destroying hemoglobin. However, VvpE expression, on both the transcriptional and protein levels, was suppressed in iron-limited media. However, vvpE transcription, but not extracellular VvpE production, was reactivated by the addition of hemoglobin or inorganic iron into iron-limited media. Moreover, vvpE transcription began only in the late growth phase when V. vulnificus had already consumed most of the iron for growth. In addition, neither vvpE mutation nor in trans vvpE complementation affected the ability of V. vulnificus to acquire iron or to grow in iron-limited media or in cirrhotic ascites containing hemoglobin. Hemoglobin added into iron-limited media was not destroyed, but gradually formed an insoluble aggregate during culture; this aggregation of hemoglobin occurred regardless of vvpE mutation or complementation. These results indicate that VvpE is not required for efficient iron uptake from hemoglobin. On the contrary, hemoglobin or iron is required for efficient vvpE transcription. In addition, a discrepancy exists between vvpE transcription and extracellular VvpE production in iron-limited media containing inorganic iron or hemoglobin, which suggests that additional unknown posttranscriptional events may be involved in the extracellular production of VvpE.

• Journal of Microbiology and Biotechnology
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• v.25 no.2
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• pp.302-306
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• 2015

VvpM, one of the extracellular metalloproteases produced by Vibrio vulnificus, induces apoptotic cell death via a pathway consisting of ERK activation, cytochrome c release, and activation of caspases-9 and -3. VvpM-treated cells also showed necrotic cell death as stained by propidium iodide (PI). The percentage of PI-stained cells was decreased by pretreatment with Necrostatin-1, indicating that VvpM-mediated cell death occurs through necroptosis. The appearance of autophagic vesicles and lipidated form of light-chain-3B in rVvpM-treated cells suggests an involvement of autophagy in this process. Therefore, the multifarious action of VvpM might be one of the factors responsible for V. vulnificus pathogenesis.

• Microbiology and Biotechnology Letters
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• v.36 no.1
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• pp.6-11
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• 2008

To check the microbiological safety with respect to increased virulence of surviving pathogens after irradiation, in this study, the transcriptional change of vvp gene encoding metalloprotease, which is one of the typical virulence factors of Vibrio mulnificus, was monitored by real-time PCR during the course of growth cycle after reinoculation of irradiated Vibrio. When V. vulnificus was exposed to a dose of 0.5 and 1 kGy, the lag period before growth resumption of sub-cultures became longer than non-irradiated counterpart as increase of irradiation dose. In the case of non-irradiated culture, the transcription of vvp was significantly activated at 15 h after inoculation, when bacterial growth reached the stationary phase, and the highest level of pretense activity (686 U/mL) was measured at the same time. Interestingly, vvp expression of irradiated Vibrio was turned up earlier than non-irradiated Vibrio during the mid log phase of growth, whereas these rapid induction of vvp expression from irradiated cells didn't result in an increase of metalloprotease production. When Vibrio was irradiated at 0.5 and 1 kGy, the protease activities peaked at 18 h after inoculation and the levels of activities were lower 1.2- and 1.4-fold, respectively, compared to the non-irradiated counterpart. Results from this study indicate that gamma radiation is not likely to activate the virulence ability of surviving Vibrio.

• Journal of Environmental Science International
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• v.19 no.10
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• pp.1187-1201
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• 2010

The formation and development conditions of the cloud streets over the yellow sea by the Cold Surge of Siberian Anticyclone Expansion which produce the heavy snowfall events over the southwestern coast, Honam District of the Korean peninsula, has been investigated through analyses of the three dimensional snow cloud structures by using the CAPPI, RHI, VAD and VVP data of X-band Radar at Muan Weather Observatory and S-band Radar at Jindo Weather Station. The data to be used are obtained from January 04, 2003, when heavy snow storm hits on Gwangju and Honam District. The PPI Radar images show that the cloud bands distribute in perpendicular to the expansion direction of the high pressure and that the radius of cloud cells is about 5~8 km with 20~30 dBz and distance between each cell is about 10 km. And but the vertical Radar images show that the cloud street is a small scale convective type cloud within height of about 3 km where a stable layer exists. From the VVP images, the time period of the high pressure expansion, the moving direction and development stages of the system are delineated. Finally, the vertical distribution of wind direction is fairly constants, while the wind speed sheer increases with altitude to 3 km.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2020.10a
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• pp.220-220
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• 2020

Astaxanthin, a natural carotenoid component of shrimp, has been used as a food additive for the treatment of various diseases, but a functional role of Astaxanthin Nanosphere (AN) in the regulation of intestinal mucin (Muc) 2 production during bacterial infection has not described yet. In this study, we have investigated the effect of AN prepared from astaxanthin during Muc2 repression elicited by the Gram-negative bacterium V. vulnificus in human gastrointestinal epithelial (HT-29) cells. AN significantly inhibited the level of ROS production and PKC activation in recombinant protein (r) VvpE-stimulated HT-29 cells. Moreover, AN inhibited the PKC-mediated phosphorylation of extracellular signal-regulated kinase and nuclear factor-kappa B responsible for region-specific hypermethylation in the Muc2 promoter in rVvpE-treated HT-29 cells. In the mouse models of V. vulnificus infection, treatment with AN maintained the level of Muc2 expression in the intestine. On the basis of these results, we suggest that AN blocks the hypermethylation of the Muc2 promoter to restore the level of Muc2 production in HT-29 cells infected with V. vulnificus.

• Korean Journal of Microbiology
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• v.41 no.3
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• pp.168-176
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• 2005

Vibrio vulnificus, one of the marine bacterial pathogens causing septicemia, was detected using molecular methods, namely, PCR and/or Southern hybridization, and real-time PCR. Extracted and purified total DNAs by using commercial kits were used as templates for PCR. Multiplex-PCR was conducted by employing three sets of primers for the genes, hemolysin (vvhA), phosphomannomutase (pmm), and metalloprotease (vvpE), for V vulnificus virulence. The presence of DMSO ($5\%$) and BSA ($0.1\%$) in PCR reaction mixture improved a detection efficiency by higher PCR band intensities. TaqMan real-time PCR was carried out by using gene segment of vvhA as a target. Detection limit of PCR/Southern hybridization without enrichments was to be around $10^2\;cells\;g^{-1}$ of sample. However, those three methods using the enrichment at $35^{\circ}C$ in APW showed high sensitivity ($2\~10\;cells\;g^{-1}$ of sediments). Highly sensitive detection of V vulnificus by real-time PCR was achieved within $5\~6$ hr, whereas the detection by PCR/Southern hybridization required about 36 hr. Thus, it was evident that real-time PCR is the most rapid and efficient method for detecting V vulnificus in tidal flat sediments.

• Journal of Microbiology and Biotechnology
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• v.13 no.6
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• pp.1021-1026
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• 2003

Numerous secreted and cell-associated virulence factors have been proposed to account for the fulminating and destructive nature of Vibrio vulnificus infections. Among the putative virulence factors are an elastase, elastolytic protease, and a cytolytic hemolysin. Effects of the elastase on the hemolysin were assessed by evaluating changes of hemolytic activities either in the presence or absence of the protease. Although hemolytic activity in the culture supernatant was lowered by the purified elastase added in vitro, the cellular level of hemolytic activity was unaffected by the mutation of vvpE encoding the elastase. Growth kinetic studies revealed that hemolysin reached its maximum level in the exponential phase of growth, and the elastase appeared at the onset of the stationary phase. These results have provided insight into the regulation of virulence factors: temporally coordinate regulation of virulence factors is essential for the overall success of the pathogen during pathogenesis.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.442-442
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• 2012

PEDOT[Poly(3,4-Ethylenedioxythiophene)]박막의 제작은 산화촉매제를 이용한 기상중합(Vapor Phase Polymerization)방법을 통해 최근 활발히 연구되어 지고 있다. 기상중합된 PEDOT박막의 특성은 박막의 중합의 정도와 성장 형상에 따라 그 특성이 크게 좌우된다. PEODT박막의 효율적인 중합에 있어 산화촉매제의 균일한 도포는 매우 중요하다. PEDOT의 효율적인 중합과 균일도포를 위해 산화촉매제에 DUDO와 PEG-PPG-PEG를 첨가한 혼합용액을 제작 VPP방법을 통해 PEDOT박막의 제작을 시도하였다. 그 결과 spin-coating 시 산화촉매 혼합용액의 균일한 도포가 관찰 되었으며 산화촉매제만 사용하여 제작된 박막에 비해 전도도와 막질이 향상된 PEDOT박막이 제작되었다. 이러한 결과는 산화촉매용액에 첨가된 PEG-PPG-PEG와 DUDO의 영향으로 PEG-PPG-PEG는 oxdiant용액의 균일 도포를 도왔으며 Inhibitor로 작용하는 DUDO는 PEDOT성장에 있어 불균일 결정성장을 억제하여 조밀한 PEDOT 박막 성장을 도운 것으로 생각된다. PEDOT 박막의 특성평가에는 Field Emission-Scanning Electron Microscopy, 4-Pointprobe, Optical microscopy 등이 사용되었다. 이러한 고전도도의 PEDOT박막을 OTFT의 전극소재로 사용한다면 OTFT소자의 성능 향상에있어 크게 기여 할 것으로 기대된다.

• 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 Life Science
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• v.14 no.2
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• pp.362-367
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• 2004

For better understanding of the host infection mechanism of Vibrio, a Vibrio parahaemolyticus collagenase mutant was generated by insertional inactivation of a vppC gene encoding extracellular collagenase. A recombinant DNA containing vppC::nptII was cloned into a suicide plasmid pDMS197, resulted in pVCM03. The recombinant suicide plasmid pVCM03 contained in E. coli $\chi$7213 was transferred to a wild-type V. parahaemolyticus 04 through conjugation. The recombinant vppC::nptII DNA in pVCM03 was exchanged with wild-type allele by homologous recombination resulting vppC mutant, V. parahaemolyticus CM. The mutant was selected and screened on TCBS media containing 10% sucrose and kanamycin. The mutation by allele exchange was confirmed with the comparison of the size of DNAs amplified by PCR. V. parahaemolyticus CM showed at least 4-fold less collagen-degrading activity than those of wild-type, and the mutant exhibited less cytotoxicity than that of wild-type in MTT assay.