Repression of VvpM Protease Expression by Quorum Sensing and the cAMP-cAMP Receptor Protein Complex in Vibrio vulnificus.

Septicemia-causing Vibrio vulnificus produces at least three exoproteases, VvpE, VvpS, and VvpM, all of which participate in interactions with human cells. Expression of VvpE and VvpS is induced in the stationary phase by multiple transcription factors, including sigma factor S, SmcR, and the cAMP-cAMP receptor protein (cAMP-CRP) complex. Distinct roles of VvpM, such as induction of apoptosis, lead us to hypothesize VvpM expression is different from that of the other exoproteases. Its transcription, which was found to be independent of sigma S, is induced at the early exponential phase and then becomes negligible upon entry into the stationary phase. SmcR and CRP were studied regarding the control of vvpM expression. Transcription of vvpM was repressed by SmcR and cAMP-CRP complex individually, which specifically bound to the regions -2 to +20 and +6 to +27, respectively, relative to the vvpM transcription initiation site. Derepression of vvpM gene expression was 10- to 40-fold greater in an smcR crp double mutant than in single-gene mutants. Therefore, these results show that the expression of V. vulnificus exoproteases is differentially regulated, and in this way, distinct proteases can engage in specific interactions with a host.IMPORTANCE An opportunistic human pathogen, Vibrio vulnificus produces multiple extracellular proteases that are involved in diverse interactions with a host. The total exoproteolytic activity is detected mainly in the supernatants of the high-cell-density cultures. However, some proteolytic activity derived from a metalloprotease, VvpM, was present in the supernatants of the low-cell-density cultures sampled at the early growth period. In this study, we present the regulatory mechanism for VvpM expression via repression by at least two transcription factors. This type of transcriptional regulation is the exact opposite of those for expression of the other V. vulnificus exoproteases. Differential regulation of each exoprotease's production then facilitates the pathogen's participation in the distinct interactions with a host.

Stationary-phase induction of vvpS expression by three transcription factors: repression by LeuO and activation by SmcR and CRP.

An exoprotease of Vibrio vulnificus, VvpS, exhibits an autolytic function during the stationary phase. To understand how vvpS expression is controlled, the regulators involved in vvpS transcription and their regulatory mechanisms were investigated. LeuO was isolated in a ligand-fishing experiment, and experiments using a leuO-deletion mutant revealed that LeuO represses vvpS transcription. LeuO bound the extended region including LeuO-binding site (LBS)-I and LBS-II. Further screening of additional regulators revealed that SmcR and cyclic adenosine monophosphate-receptor protein (CRP) play activating roles in vvpS transcription. SmcR and CRP bound the regions overlapping LBS-I and -II, respectively. In addition, the LeuO occupancy of LBS-I and LBS-II was competitively exchanged by SmcR and CRP, respectively. To examine the mechanism of stationary-phase induction of vvpS expression, in vivo levels of three transcription factors were monitored. Cellular level of LeuO was maximal at exponential phase, while those of SmcR and CRP were maximal at stationary phase and relatively constant after the early-exponential phase, respectively. Thus, vvpS transcription was not induced during the exponential phase by high cellular content of LeuO. When entering the stationary phase, however, LeuO content was significantly reduced and repression by LeuO was relieved through simultaneous binding of SmcR and CRP to LBS-I and -II, respectively.

Deacylated lipopolysaccharides inhibit biofilm formation by Gram-negative bacteria.

The extracellular polysaccharides of Vibrio vulnificus play different roles during biofilm development. Among them, the effect of lipopolysaccharide (LPS), which is crucial for bacterial adherence to surfaces during the initial stage of biofilm formation, on the formation process was examined using various types of LPS extracts. Exogenously added LPS strongly inhibited biofilm formation in a dose-dependent manner. In addition, the exogenous addition of a deacylated form of LPS (dLPS) also inhibited biofilm formation. However, an LPS fraction extracted from a mutant not able to produce O-antigen polysaccharides (O-Ag) did not have an inhibitory effect. Furthermore, biofilm formation by several Gram-negative bacteria was inhibited by dLPS addition. In contrast, biofilm formation by Gram-positive bacteria was not influenced by dLPS but was affected by lipoteichoic acid. Therefore, this study demonstrates that O-Ag in LPS is important for inhibiting biofilm formation and may serve an efficient anti-biofilm agent specific for Gram-negative bacteria.

Regulation of haemolysin (VvhA) production by ferric uptake regulator (Fur) in Vibrio vulnificus: repression of vvhA transcription by Fur and proteolysis of VvhA by Fur-repressive exoproteases.

VvhA produced by Vibrio vulnificus exhibits cytolytic activity to human cells including erythrocytes. Since haemolysis by VvhA may provide iron for bacterial growth and pathogenicity, we investigated the expression of VvhA to elucidate the regulatory roles of Fur, a major transcription factor controlling iron-homeostasis. Fur repressed the transcription of vvhBA operon via binding to the promoter region. However, haemolysin content and haemolytic activity were lowered in cell-free supernatant of fur mutant. This discrepancy between the levels of vvhA transcript and VvhA protein in fur mutant was caused by exoproteolytic activities of the elastase VvpE and another metalloprotease VvpM, which were also regulated by Fur. vvpE gene expression was repressed by Fur via binding to the Fur-box homologous region. Regulation of VvpM expression by Fur did not occur at the level of vvpM transcription. In vitro proteolysis assays showed that both proteases efficiently degraded VvhA. In addition, the extracellular levels of VvhA were higher in culture supernatants of vvpE or vvpM mutants than in the wild type. Thus this study demonstrates that Fur regulates haemolysin production at the transcription level of the vvhBA operon and at the post-translation level by regulating the expressions of two VvhA-degrading exoproteases, VvpE and VvpM.

Plasma in dentistry: a review of basic concepts and applications in dentistry.

OBJECTIVE: Plasma-related technologies are essential in modern industries. Recently, plasma has attracted increased attention in the biomedical field. This paper provides a basic knowledge of plasma and a narrative review of plasma applications in dentistry. MATERIALS AND METHODS: To review plasma applications in dentistry, an electronic search in PubMed, SCOPUS and Google scholar up to December 2012 was done. This was followed by extensive hand searching using reference lists from relevant articles. CONCLUSION: There have been attempts to apply plasma technology in various fields of dentistry including surface modifications of dental implants, adhesion, caries treatment, endodontic treatment and tooth bleaching. Although many studies were in early stages, the potential value of plasma for dental applications has been demonstrated. To enlarge the scope of plasma applications and put relevant research to practical use, interdisciplinary research with participation of dental professionals is required.

The role of failure modes and effects analysis in showing the benefits of automation in the blood bank.

BACKGROUND: Failure modes and effects analysis (FMEA) is a risk management tool used by the manufacturing industry but now being applied in laboratories. STUDY DESIGN AND METHODS: Teams from six South Korean blood banks used this tool to map their manual and automated blood grouping processes and determine the risk priority numbers (RPNs) as a total measure of error risk. RESULTS: The RPNs determined by each of the teams consistently showed that the use of automation dramatically reduced the RPN compared to manual processes. In addition, FMEA showed where the major risks occur in each of the manual processes and where attention should be prioritized to improve the process. Despite no previous experience with FMEA, the teams found the technique relatively easy to use and the subjectivity associated with assigning risk numbers did not affect the validity of the data. CONCLUSION: FMEA should become a routine technique for improving processes in laboratories.

Analysis of stored and transplanted cord blood units from KoreaCORD: reappraisal of banking guidelines and selection strategy.

BACKGROUND: We analyzed the characteristics of stored and transplanted cord blood (CB) units from the Korean network for public CB donation (KoreaCORD) to reassess the banking guidelines and optimize CB selection based on cell dose and human leukocyte antigen (HLA) mismatching. STUDY DESIGN AND METHODS: We retrospectively reviewed data, with regard to total nucleated cell (TNC) count and HLA match in the KoreaCORD registry from August 2001 to December 2010. RESULTS: A total of 21,914 CB units have been registered, of which 904 units (4.1%) contained less than 5 × 10(8) TNCs, which did not meet the present storage criteria for public CB banking in Korea. Although the proportion of stored CBs providing TNC of 5 × 10(8) to 7.9 × 10(8) was 45.7%, only 22.0% of all transplanted CBs were derived from these stored CBs. In the single CB transplantation setting, 79% (85/108) of CB units provided 4 × 10(7) TNCs/kg or more in the transplanted one-mismatch (1-MM) CB units and 51% (19/37) of CBs provided 6 × 10(7) TNCs/kg or more in the transplanted 2-MM CB units. CONCLUSIONS: The minimal requirement of TNCs for banking of CB units for public banking should be evaluated and increased to support the selection of CB units with higher cell doses, especially for use in the 1- and 2-MM transplant settings.

Identification of α-11 giardin as a flagellar and surface component of Giardia lamblia.

Giardia lamblia is a protozoan pathogen with distinct cytoskeletal structures, including median bodies and eight flagella. In this study, we examined components comprising G. lamblia flagella. Crude flagellar extracts were prepared from G. lamblia trophozoites, and analyzed by two-dimensional (2-D) gel electrophoresis. The 19 protein spots were analyzed by MALDI-TOF mass spectrometry, identifying ten metabolic enzymes, six distinct giardins, Giardia trophozoite antigen 1, translational initiation factor eIF-4A, and an extracellular signal-regulated kinase 2. Among the identified proteins, we studied α-11 giardin which belongs to a group of cytoskeletal proteins specific to Giardia. Western blot analysis and real-time PCR indicated that expression of α-11 giardin is not significantly increased during encystation of G. lamblia. Immunofluorescence assays using anti-α-11 giardin antibodies revealed that α-11 giardin protein mainly localized to the plasma membranes and basal bodies of the anterior flagella of G. lamblia trophozoites, suggesting that α-11 giardin is a genuine component of the G. lamblia cytoskeleton.

Functional characterization of EpsC, a component of the type II secretion system, in the pathogenicity of Vibrio vulnificus.

EpsC, one of the components comprising the type II secretion system (T2SS), was isolated from a human-pathogenic bacterium, Vibrio vulnificus, to evaluate its role in eliciting virulence. An espC-deleted mutant of V. vulnificus displayed a reduced cytotoxicity to the human cell line HEp-2 and an attenuated virulence in a mouse model. This mutant exhibited dramatic defects in the secretion of diverse extracellular proteins, such as outer membrane proteins, transporters, and the known secreted factors, notably, a hemolysin (VvhA) and an elastase (VvpE). A defect in its secretion of proteins was restored by in trans complementation of the intact epsC gene. Analyses of cellular fractions revealed that VvhA and VvpE of the ΔepsC mutant were not excreted outside the cell but were present mainly in the periplasmic space. Examination of a V. vulnificus mutant deficient in TolC, a component of the T1SS, showed that it is not involved in the secretion of VvhA and VvpE but that it is necessary for the secretion of another major toxin of V. vulnificus, RtxA. Therefore, the T2SS is required for V. vulnificus pathogenicity, which is mediated by at least two secreted factors, VvhA and VvpE, via facilitating the secretion and exposure of these factors to host cells.

Role of DegQ in differential stability of flagellin subunits in Vibrio vulnificus.

Biofilm formation of Vibrio vulnificus is initiated by adherence of flagellated cells to surfaces, and then flagellum-driven motility is not necessary during biofilm maturation. Once matured biofilms are constructed, cells become flagellated and swim to disperse from biofilms. As a consequence, timely regulations of the flagellar components' expression are crucial to complete a biofilm life-cycle. In this study, we demonstrated that flagellins' production is regulated in a biofilm stage-specific manner, via activities of a protease DegQ and a chaperone FlaJ. Among four flagellin subunits for V. vulnificus filament, FlaC had the highest affinities to hook-associated proteins, and is critical for maturating flagellum, showed the least susceptibility to DegQ due to the presence of methionine residues in its DegQ-sensitive domains, ND1 and CD0. Therefore, differential regulation by DegQ and FlaJ controls the cytoplasmic stability of flagellins, which further determines the motility-dependent, stage-specific development of biofilms.

Two dominant patterns of low anterior resection syndrome and their effects on patients' quality of life.

To identify low anterior resection syndrome (LARS) patterns and their associations with risk factors and quality of life (QOL). This cross-sectional study analyzed patients who underwent restorative anterior resection for left-sided colorectal cancer at Seoul National University Hospital, Seoul, Republic of Korea. We administered LARS questionnaires to assess bowel dysfunction and quality of life between April 2017 and November 2019. LARS patterns were classified based on factor analyses. Variable effects on LARS patterns were estimated using logistic regression analysis. The risk factors and quality of life associated with dominant LARS patterns were analyzed. Data of 283 patients with a median follow-up duration of 24 months were analyzed. Major LARS was observed in 123 (43.3%) patients. Radiotherapy (odds ratio [OR]: 2.851, 95% confidence interval [95% CI]: 2.504-43.958, p = 0.002), low anastomosis (OR: 10.492, 95% CI: 2.504-43.958, p = 0.001), and complications (OR: 2.163, 95% CI: 1.100-4.255, p = 0.025) were independently associated with major LARS. LARS was classified into incontinence- or frequency-dominant types. Risk factors for incontinence-dominant LARS were radiotherapy and complications, whereas those for frequency-dominant LARS included low tumor location. Patients with incontinence-dominant patterns showed lower emotional function, whereas those with frequency-dominant patterns showed lower global health QOL, lower emotional, cognitive, and social functions, and higher incidence of pain and diarrhea. Frequency-dominant LARS had a greater negative effect on QOL than incontinence-dominant LARS. These patterns could be used for preoperative prediction and postoperative treatment of LARS.

PXO_RS20535, Encoding a Novel Response Regulator, Is Required for Chemotactic Motility, Biofilm Formation, and Tolerance to Oxidative Stress in Xanthomonas oryzae pv. oryzae.

Xanthomonas oryzae pv. oryzae (Xoo), a causal agent of bacterial leaf blight of rice, possesses two-component regulatory systems (TCSs) as an intracellular signaling pathway. In this study, we observed changes in virulence, biofilm formation, motility, chemotaxis, and tolerance against oxidative stress of a knockout mutant strain for the PXO_RS20535 gene, encoding an orphan response regulator (RR). The mutant strain lost virulence, produced significantly less biofilm, and showed remarkably reduced motility in swimming, swarming, and twitching. Furthermore, the mutant strain lost glucose-guided movement and showed clear diminution of growth and survival in the presence of H2O2. These results indicate that the RR protein encoded in the PXO_RS20535 gene (or a TCS mediated by the protein) is closely involved in regulation of biofilm formation, all types of motility, chemotaxis, and tolerance against reactive oxygen species (ROS) in Xoo. Moreover we found that the expression of most genes required for a type six secretion system (T6SS) was decreased in the mutant, suggesting that lack of the RR gene most likely leads to defect of T6SS in Xoo.

Two-year clinical effectiveness of adhesives and retention form on resin composite restorations of non-carious cervical lesions.

The current study investigated the clinical effectiveness of three adhesives and the use of retention form in Class V resin composite restorations of the non-carious cervical lesion (NCCL) over a two-year period. One-hundred and fifty NCCLs in 39 patients were restored with resin composites according to six experimental protocols combining the presence or absence of retention form and three adhesives: ScotchBond Multi-Purpose (MP, 3M ESPE), an experimental adhesive (EX, Vericom) and Adper Prompt (AP, 3M ESPE). All restorations were evaluated at baseline, 6, 12 and 24 months. Modified United States Public Health Service (USPHS) criteria were used to evaluate the restorations. MP was found to have significantly superior marginal adaptation than AP in cumulative logistic regression analysis (odds ratio, 2.12; 95% confidence interval, 1.05-4.31; p = 0.0397). In analysis using the Pearson's Chi-square or Fisher's Exact Test to compare the clinical performance of restorations with and without retention form, EX with retention form showed a significantly higher retention rate at two years than that without retention form (p = 0.0089). Restorations with retention form also showed significantly less marginal discoloration than those without retention form in all three adhesives (p = 0.0336).

Role of Flagellin-Homologous Proteins in Biofilm Formation by Pathogenic Vibrio Species.

The pathogenic bacterium Vibrio vulnificus exhibits the ability to form biofilm, for which initiation is dependent upon swimming motility by virtue of a polar flagellum. The filament of its flagellum is composed of multiple flagellin subunits, FlaA, -B, -C, and -D. In V. vulnificus genomes, however, open reading frames (ORFs) annotated by FlaE and -F are also present. Although neither FlaE nor FlaF is involved in filament formation and cellular motility, they are well expressed and secreted to the extracellular milieu through the secretion apparatus for flagellar assembly. In the extrapolymeric matrix of V. vulnificus biofilm, significant levels of FlaEF were detected. Mutants defective in both flaE and flaF formed significantly decreased biofilms compared to the wild-type biofilm. Thus, the potential role of FlaEF during the biofilm-forming process was investigated by exogenous addition of recombinant FlaEF (rFlaEF) to the biofilm assays. The added rFlaE and rFlaF were predominantly incorporated into the biofilm matrix formed by the wild type. However, biofilms formed by a mutant defective in exopolysaccharide (EPS) biosynthesis were not affected by added FlaEF. These results raised a possibility that FlaEF specifically interact with EPS within the biofilm matrix. In vitro pulldown assays using His-tagged rFlaEF or rFlaC revealed the specific binding of EPS to rFlaEF but not to rFlaC. Taken together, our results demonstrate that V. vulnificus FlaEF, flagellin-homologous proteins (FHPs), are crucial for biofilm formation by directly interacting with the essential determinant for biofilm maturation, EPS. Further analyses performed with other pathogenic Vibrio species demonstrated both the presence of FHPs and their important role in biofilm formation.IMPORTANCE Flagellar filaments of the pathogenic Vibrio species, including V. vulnificus, V. parahaemolyticus, and V. cholerae, are composed of multiple flagellin subunits. In their genomes, however, there are higher numbers of the ORFs encoding flagellin-like proteins than the numbers of flagellin subunits required for filament assembly. Since these flagellin-homologous proteins (FHPs) are well expressed and excreted to environments via a flagellin transport channel, their extracellular role in the pathogenic Vibrio has been enigmatic. Their biological significance, which is not related with flagellar functions, has been revealed to be in maturation of biofilm structures. Among various components of the extracellular polymeric matrix produced in the V. vulnificus biofilms, the exopolysaccharides (EPS) are dominant constituents and crucial in maturation of biofilms. The enhancing role of the V. vulnificus FHPs in biofilm formation requires the presence of EPS, as indicated by highly specific interactions among two FHPs and three EPS.

Genome-wide Screening to Identify Responsive Regulators Involved in the Virulence of Xanthomonas oryzae pv. oryzae.

Two-component systems (TCSs) are critical to the pathogenesis of Xanthomonas oryzae pv. oryzae (Xoo). We mutated 55 of 62 genes annotated as responsive regulators (RRs) of TCSs in the genome of Xoo strain PXO99A and identified 9 genes involved in Xoo virulence. Four (rpfG, hrpG, stoS, and detR) of the 9 genes were previously reported as key regulators of Xoo virulence and the other 5 have not been characterized. Lesion lengths on rice leaves inoculated with the mutants were shorter than those of the wild type and were significantly restored with gene complementation. The population density of the 5 mutants in planta was smaller than that of PXO99A at 14 days after inoculation, but the growth curves of the mutants in rich medium were similar to those of the wild type. These newly reported RR genes will facilitate studies on the function of TCSs and of the integrated regulation of TCSs for Xoo pathogenesis.

Bilateral peripheral infiltrative keratitis after LASIK.

PURPOSE: To present a case of peripheral infiltrative keratitis mimicking infectious keratitis on the flap margin and limbus, which appeared on the first postoperative day after the laser in situ keratomileusis (LASIK). METHODS: A 36-year-old woman who underwent uneventful bilateral simultaneous LASIK developed multiple round infiltrate along the flap margin reaching to limbus from the 11 o'clock to 6 o'clock area in both eyes. RESULTS: The flap was lifted and irrigation was performed with antibiotics. but infiltration seemed to appear again. The infiltrate was more concentrated at the periphery and was extended to the limbus. Direct smear and culture for bacteria and fungus were negative. Topical prednisolone acetate 1% eye drops was added, infiltrative condition was resolved. CONCLUSIONS: LASIK induced peripheral infiltrative keratitis, in which infectious origin was ruled out, is reported.

The effectiveness of real-time PCR assay, compared with microbiologic results for the diagnosis of pulmonary tuberculosis.

BACKGROUND: The incidence of tuberculosis (TB) in Korea is relatively high compared to the other Organisation for Economic Co-operation and Development (OECD) countries, with a prevalence of 71 per 100,000 in 2012, although the incidence is declining. Real-time polymerase chain reaction (PCR) has been introduced for the rapid diagnosis of TB. Recently, its advantage lies in higher sensitivity and specificity for the diagnosis of TB. This study evaluated the clinical accuracy of real-time PCR using respiratory specimens in a clinical setting. METHODS: Real-time PCR assays using sputum specimens and/or bronchoscopic aspirates from 2,877 subjects were reviewed retrospectively; 2,859 subjects were enrolled. The diagnosis of TB was determined by positive microbiology, pathological findings of TB in the lung and pleura, or clinical suspicion of active TB following anti-TB medication for more than 6 months with a favorable response. RESULTS: Sensitivity, specificity, and accuracy were 44%, 99%, and 86% from sputum, and 65%, 97%, and 87% from bronchoscopic aspirates, respectively. For overall respiratory specimens, sensitivity was 59%, specificity was 98%, and accuracy increased to 89%. CONCLUSION: Positivity in real-time PCR using any respiratory specimens suggests the possibility of active TB in clinically suspected cases, guiding to start anti-TB medication. Real-time PCR from selective bronchoscopic aspirates enhances the diagnostic yield much more when added to sputum examination.

VvpM induces human cell death via multifarious modes including necroptosis and autophagy.

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.

Immunomodulatory effects of kimchi in chinese healthy college students: a randomized controlled trial.

This study examined the potential immunomodulatory effects of Kimchi, a traditional fermented Korean vegetable, in healthy Chinese college students. The four-week clinical-trial (randomized, open-label, prospective, controlled) was followed by a one week wash-out period. Healthy Chinese college students (over 20 years of age with a body mass index of 18.5-23.0 kg/m(2)) volunteered for this study. Forty-three students were randomly classified into two groups, Kimchi (n = 21, supplemented with 100 g of Kimchi per day) or non-Kimchi (n = 22, supplemented with 100 g of radish per day, control) groups. During the four-week intervention period, students were asked to maintain their usual diet and activity, and instructed not to take any medications, functional food products, or dietary supplements. Anthropometrics, nutritional intake, and blood immune parameters (lymphocyte subsets, cytokines, and immunoglobulins) were measured before and after the four weeks of intervention. Thirty-nine students (19 in the Kimchi group, 20 in the non-Kimchi group) finished the study. After the intervention, no significant changes were observed in lymphocyte subsets (T-cell, B-cell, NK cell), pro-inflammatory cytokines (IL-6, TNF-α), anti-inflammatory cytokines (IL-4 and IL-10), and immunoglobulins (Ig A, G, and M) between groups in either the Kimchi or non-Kimchi. These results suggest that the short-term consumption of Kimchi has no immunomodulatory effects in healthy Chinese college students.

VvpM, an extracellular metalloprotease of Vibrio vulnificus, induces apoptotic death of human cells.

A pathogenic bacterium, Vibrio vulnificus produces various extracellular proteases including the elastolytic metalloprotease, VvpE. In silico analysis of its genome revealed a VvpE-homologous protease, VvpM whose proteolytic activity was abolished by specific inhibitors against metalloproteases. To investigate whether this newly identified protease has pathogenic role in host interaction in addition to proteolytic role, human cell lines were incubated with recombinant VvpM (rVvpM). rVvpM-challenged cells showed typical morphological changes found in cells under apoptosis. Apoptotic cell death was further evidenced by estimating the Annexin V-stained cells, whose proportions were dependent upon the concentrations of rVvpM treated to human cells. To elucidate the signaling pathway for VvpM-induced apoptosis, three MAPKs were tested if their activation were mediated by rVvpM. ERK1/2 was phosphorylated by treatment of rVvpM and rVvpM-induced cell death was blocked by a specific inhibitor against ERK1/2. In rVvpM-treated cells, the cytosolic levels of cytochrome c were increased in a VvpM concentration-dependent manner, while the levels of cytochrome c in mitochondria were decreased. Cell deaths were accompanied by apparent cleavages of procaspases-9 and -3 to the active caspases-9 and -3, respectively. Therefore, this study demonstrates that an extracellular metalloprotease of V. vulnificus, VvpM induces apoptosis of human cells via a pathway consisting of ERK activation, cytochrome c release, and then activation of caspases-9 and -3.