Journal of Microbiology

Journal Articles

Flavihumibacter fluminis sp. nov. and Flavihumibacter rivuli sp. nov., isolated from a freshwater stream: Miri S. Park , Hyeonuk Sa , Ilnam Kang , Jang-Cheon Cho; J. Microbiol. 2022;60(8):806-813. Published online July 29, 2022; DOI: https://doi.org/10.1007/s12275-022-2298-2

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Two Gram-stain-positive, aerobic, chemoheterotrophic, nonmotile, rod-shaped, and yellow-pigmented bacterial strains, designated IMCC34837T and IMCC34838T, were isolated from a freshwater stream. Results of 16S rRNA gene-based phylogenetic analyses showed that strains IMCC34837T and IMCC- 34838T shared 96.3% sequence similarity and were most closely related to Flavihumibacter profundi Chu64-6-1T (99.6%) and Flavihumibacter cheonanensis WS16T (96.4%), respectively. Complete whole-genome sequences of strains IMCC- 34837T and IMCC34838T were 5.0 Mbp and 4.3 Mbp of genome size with 44.5% and 47.9% of DNA G + C contents, respectively. Average nucleotide identity (ANI) and digital DNA- DNA hybridization (dDDH) values between the two strains were 70.0% and 17.9%, repectively, revealing that they are independent species. The two strains showed ≤ 75.2% ANI and ≤ 19.3% dDDH values to each closely related species of the genus Flavihumibacter, indicating that the two strains represent each novel species. Major fatty acid constituents of strain IMCC34837T were iso-C15:0, iso-C15:1 G and anteiso-C15:0 and those of strain IMCC34838T were iso-C15:0 and iso-C15:1 G. The predominant isoprenoid quinone detected in both strains was menaquinone-7 (MK-7). Major polar lipids of both strains were phosphatidylethanolamine, aminolipids, and glycolipids. Based on the phylogenetic and phenotypic characterization, strains IMCC34837T and IMCC34838T were considered to represent two novel species within the genus Flavihumibacter, for which the names Flavihumibacter fluminis sp. nov. and Flavihumibacter rivuli sp. nov. are proposed with IMCC34837T (= KACC 21752T = NBRC 115292T) and IMCC34838T (= KACC 21753T = NBRC 115293T) as the type strains, respectively.

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Update on the proposed minimal standards for the use of genome data for the taxonomy of prokaryotes
Raúl Riesco, Martha E. Trujillo
International Journal of Systematic and Evolutionary Microbiology .2024;[Epub] CrossRef
Leuconostoc aquikimchii sp. nov., a Lactic Acid Bacterium Isolated from Cabbage Watery Kimchi
Subin Kim, Se Hee Lee, Ki Hyun Kim, Misun Yun
Journal of Microbiology.2024; 62(12): 1089. CrossRef
Congregibacter variabilis sp. nov. and Congregibacter brevis sp. nov. Within the OM60/NOR5 Clade, Isolated from Seawater, and Emended Description of the Genus Congregibacter
Hyeonsu Tak, Miri S. Park, Hyerim Cho, Yeonjung Lim, Jang-Cheon Cho
Journal of Microbiology.2024; 62(9): 739. CrossRef
Flavobacterium rivulicola sp. nov., Isolated from a Freshwater Stream
Sumin Kim, Miri S. Park, Ilnam Kang, Jang-Cheon Cho
Current Microbiology.2024;[Epub] CrossRef
Validation List no. 211. Valid publication of new names and new combinations effectively published outside the IJSEM
Aharon Oren, Markus Göker
International Journal of Systematic and Evolutionary Microbiology .2023;[Epub] CrossRef
Proposal of Flavihumibacter fluvii sp. nov. as a replacement name for the effectively published but invalidated epithet Flavihumibacter fluminis Park et al. 2022
Miri S. Park, Hyeonuk Sa, Ilnam Kang, Jang-Cheon Cho
Journal of Microbiology.2023; 61(6): 649. CrossRef

Whole genome and RNA sequencing of oral commensal bacterium Streptococcus anginosus subsp. anginosus with vancomycin tolerance: Kyu Hwan Kwack , Jae-Hyung Lee , Ji-Hoi Moon; J. Microbiol. 2022;60(2):167-176. Published online January 7, 2022; DOI: https://doi.org/10.1007/s12275-022-1425-4

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Abstract

“Antibiotic tolerance” promotes the rapid subsequent evolution of “antibiotic resistance,” however, it is often overlooked because it is difficult to distinguish between tolerant and susceptible organisms. A commensal bacterium S. anginosus subsp. anginosus strain KHUD_S1, isolated from dental biofilm was found to exhibit a high MBC/MIC ratio of 32 against vancomycin. We observed KHUD_S1 cells exposed to vancomycin did not grow but maintained viability. Transmission electron microscope showed KHUD_S1 cells possessed a dense, thick capsule and maintained the cell wall integrity upon vancomycin exposure. To infer the underlying mechanisms of the vancomycin tolerance in KHUD_S1, we performed whole genome sequencing and RNA sequencing. The KHUD_S1 genome carried three genes encoding branching enzymes that can affect peptidoglycan structure through interpeptide bridge formation. Global gene expression profiling revealed that the vancomycin-induced downregulation of carbohydrate and inorganic ion transport/metabolism as well as translation is less prominent in KHUD_S1 than in the vancomycin susceptible strain KHUD_S3. Based on the transcriptional levels of genes related to peptidoglycan synthesis, KHUD_S1 was determined to have a 3D peptidoglycan architecture distinct from KHUD_S3. It was found that, under vancomycin exposure, the peptidoglycan was remodeled through changes in the interpeptide bridge and transpeptidation reactions. Collectively, these features of S. anginosus KHUD_S1, including a dense capsule and differential gene expression in peptidoglycan synthesis, may contribute to vancomycin tolerance. Our results showing the occurrence of vancomycin tolerance amongst oral commensal bacteria highlight the need for considering future strategies for screening of antibiotic tolerance as an effort to reduce antibiotic resistance.

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Gut resistome profiling reveals high diversity and fluctuations in pancreatic cancer cohorts
Xudong Liu, Kexin Li, Yun Yang, Dingyan Cao, Xinjie Xu, Zilong He, Wenming Wu
Frontiers in Cellular and Infection Microbiology.2024;[Epub] CrossRef
The Sexome ‐ A proof of concept study into microbial transfer between heterosexual couples after sexual intercourse
Ruby Dixon, Siobhon Egan, Sheree Hughes, Brendan Chapman
Forensic Science International.2023; 348: 111711. CrossRef

Isolation of a novel strain, Sphingorhabdus sp. YGSMI21 and characterization of its enantioselective epoxide hydrolase activity: Jung-Hee Woo , Hae-Seon Kim , Nyun-Ho Park , Ho Young Suk; J. Microbiol. 2021;59(7):675-680. Published online June 1, 2021; DOI: https://doi.org/10.1007/s12275-021-1023-x

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Abstract

Sphingorhabdus sp. YGSMI21, a novel microbial strain with an enantioselective epoxide hydrolase activity, was isolated from tidal samples contaminated by accidental oil spills subjected to enriched culture with polycyclic aromatic hydrocarbon. This strain was able to optically decompose (R)-styrene oxide (SO) and showed 100% optical purity. In addition, it showed a good enantioselectivity for the derivatives of (S)- SO, (S)-2-chlorostyrene oxide (CSO), (S)-3-CSO and (S)-4- CSO. For (S)-2-CSO, (S)-3-CSO and (S)-4-CSO, 99.9%ee was obtained with the yield of 26.2%, 24.8%, and 11.0%, respectively, when using 10 mg cells of Sphingorhabdus sp. YGSMI21 at pH 8.0 with 4 mM racemic substrates at pH 8.0 and 25°C. The values obtained in this study for (S)-2-CSO, particularly the yield of 26.2%, is noteworthy, considering that obtaining an enantiomerically pure form is difficult. Taken together, Sphingorhabdus sp. YGSMI21 can be regarded as a wholecell biocatalyst in the production of various (S)-CSO with the chlorine group at a different position.

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Epoxide Hydrolases: Multipotential Biocatalysts
Marek Bučko, Katarína Kaniaková, Helena Hronská, Peter Gemeiner, Michal Rosenberg
International Journal of Molecular Sciences.2023; 24(8): 7334. CrossRef
Effects of submerged macrophytes (Elodea nuttallii) on water quality and microbial communities of largemouth bass (Micropterus salmoides) ponds
Zhijuan Nie, Zhaowei Zheng, Haojun Zhu, Yi Sun, Jun Gao, Jiancao Gao, Pao Xu, Gangchuan Xu
Frontiers in Microbiology.2023;[Epub] CrossRef
Description of Polaribacter batillariae sp. nov., Polaribacter cellanae sp. nov., and Polaribacter pectinis sp. nov., novel bacteria isolated from the gut of three types of South Korean shellfish
Su-Won Jeong, Jeong Eun Han, June-Young Lee, Ji-Ho Yoo, Do-Yeon Kim, In Chul Jeong, Jee-Won Choi, Yun-Seok Jeong, Jae-Yun Lee, So-Yeon Lee, Euon Jung Tak, Hojun Sung, Hyun Sik Kim, Pil Soo Kim, Dong-Wook Hyun, Jin-Woo Bae
Journal of Microbiology.2022; 60(6): 576. CrossRef

Research Support, Non-U.S. Gov'ts

VvpM, an Extracellular Metalloprotease of Vibrio vulnificus, Induces Apoptotic Death of Human Cells: Mi-Ae Lee , Jeong-A Kim , Yu Jin Yang , Mee-Young Shin , Soon-Jung Park , Kyu-Ho Lee; J. Microbiol. 2014;52(12):1036-1043. Published online November 3, 2014; DOI: https://doi.org/10.1007/s12275-014-4531-0

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Abstract

A pathogenic bacterium, Vibrio vulnificus produces various extracellular proteases including the elastolytic metalloprotease, VvpE. In silico analysis of its genome revealed a VvpEhomologous 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.

Citations

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Pathology and pathogenesis of Vibrio infection in fish: A review
Tilusha Manchanayake, Annas Salleh, Mohammad Noor Azmai Amal, Ina Salwany Md Yasin, Mohd Zamri-Saad
Aquaculture Reports.2023; 28: 101459. CrossRef
Direct and indirect effects of pathogenic bacteria on the integrity of intestinal barrier
Lin-Zhen Shu, Yi-Dan Ding, Qing-Ming Xue, Wei Cai, Huan Deng
Therapeutic Advances in Gastroenterology.2023;[Epub] CrossRef
Vibrio vulnificus PlpA facilitates necrotic host cell death induced by the pore forming MARTX toxin
Changyi Cho, Sanghyeon Choi, Myung Hee Kim, Byoung Sik Kim
Journal of Microbiology.2022; 60(2): 224. CrossRef
The DNA binding domain of theVibrio vulnificusSmcR transcription factor is flexible and binds diverse DNA sequences
Jane D Newman, Meghan M Russell, Lixin Fan, Yun-Xing Wang, Giovanni Gonzalez-Gutierrez, Julia C van Kessel
Nucleic Acids Research.2021; 49(10): 5967. CrossRef
Melatonin restores Muc2 depletion induced by V. vulnificus VvpM via melatonin receptor 2 coupling with Gαq
Young-Min Lee, Jong Pil Park, Young Hyun Jung, Hyun Jik Lee, Jun Sung Kim, Gee Euhn Choi, Ho Jae Han, Sei-Jung Lee
Journal of Biomedical Science.2020;[Epub] CrossRef
The role of Vibrio vulnificus virulence factors and regulators in its infection-induced sepsis
Gang Li, Ming-Yi Wang
Folia Microbiologica.2020; 65(2): 265. CrossRef
Intestinal epithelial cell apoptosis due to a hemolytic toxin from Vibrio vulnificus and protection by a 36 kDa glycoprotein from Rhus verniciflua Stokes
Young-Min Lee, Jong Pil Park, Kye-Taek Lim, Sei-Jung Lee
Food and Chemical Toxicology.2019; 125: 46. CrossRef
The extracellular proteases produced by Vibrio parahaemolyticus
George Osei-Adjei, Xinxiang Huang, Yiquan Zhang
World Journal of Microbiology and Biotechnology.2018;[Epub] CrossRef
Repression of VvpM Protease Expression by Quorum Sensing and the cAMP-cAMP Receptor Protein Complex in Vibrio vulnificus
Jeong-A Kim, Mi-Ae Lee, You-Chul Jung, Bo-Ram Jang, Kyu-Ho Lee, Victor J. DiRita
Journal of Bacteriology.2018;[Epub] CrossRef
Classification and structural insight into vibriolysin-like proteases of Vibrio pathogenicity
JiaFeng Huang, BingQi Zeng, Dan Liu, RiBang Wu, Jiang Zhang, BinQiang Liao, HaiLun He, Fei Bian
Microbial Pathogenesis.2018; 117: 335. CrossRef
A Vibrio vulnificus VvpM Induces IL-1β Production Coupled with Necrotic Macrophage Death via Distinct Spatial Targeting by ANXA2
Sei-Jung Lee, Young Hyun Jung, Jun Sung Kim, Hyun Jik Lee, Sang Hun Lee, Kyu-Ho Lee, Kyung Ku Jang, Sang Ho Choi, Ho Jae Han
Frontiers in Cellular and Infection Microbiology.2017;[Epub] CrossRef
Vibrio vulnificus: An Environmental and Clinical Burden
Sing-Peng Heng, Vengadesh Letchumanan, Chuan-Yan Deng, Nurul-Syakima Ab Mutalib, Tahir M. Khan, Lay-Hong Chuah, Kok-Gan Chan, Bey-Hing Goh, Priyia Pusparajah, Learn-Han Lee
Frontiers in Microbiology.2017;[Epub] CrossRef
Crystal Structure of the Regulatory Domain of AphB from Vibrio vulnificus, a Virulence Gene Regulator
Nohra Park, Saemee Song, Garam Choi, Kyung Ku Jang, Inseong Jo, Sang Ho Choi, Nam-Chul Ha
Molecules and Cells.2017; 40(4): 299. CrossRef
The hydrogen peroxide hypersensitivity of OxyR2 in Vibrio vulnificus depends on conformational constraints
Inseong Jo, Dukyun Kim, Ye-Ji Bang, Jinsook Ahn, Sang Ho Choi, Nam-Chul Ha
Journal of Biological Chemistry.2017; 292(17): 7223. CrossRef
The Makes Caterpillars Floppy (MCF)-Like Domain of Vibrio vulnificus Induces Mitochondrion-Mediated Apoptosis
Shivangi Agarwal, Yeuming Zhu, David R. Gius, Karla J. F. Satchell, S. M. Payne
Infection and Immunity.2015; 83(11): 4392. CrossRef
Stationary‐phase induction of vvpS expression by three transcription factors: repression by LeuO and activation by SmcR and CRP
Jeong‐A. Kim, Jin Hwan Park, Mi‐Ae Lee, Hyun‐Jung Lee, Soon‐Jung Park, Kun‐Soo Kim, Sang‐Ho Choi, Kyu‐Ho Lee
Molecular Microbiology.2015; 97(2): 330. CrossRef

Live and Dead GFP-Tagged Bacteria Showed Indistinguishable Fluorescence in Caenorhabditis elegans Gut: Ju-Ya Hsiao , Chun-Yao Chen , Mei-Jun Yang , Han-Chen Ho; J. Microbiol. 2013;51(3):367-372. Published online June 28, 2013; DOI: https://doi.org/10.1007/s12275-013-2589-8

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Abstract: Caenorhabditis elegans has been used for studying hostpathogen interactions since long, and many virulence genes of pathogens have been successfully identified. In several studies, fluorescent pathogens were fed to C. elegans and fluorescence observed in the gut was considered an indicator for bacterial colonization. However, the grinder in the pharynx of these nematodes supposedly crushes the bacterial cells, and the ground material is delivered to the intestine for nutrient absorption. Therefore, it remains unclear whether intact bacteria pass through the grinder and colonize in the intestine. Here we investigated whether the appearance of fluorescence is indicative of intact bacteria in the gut using both fluorescence microscopy and transmission electron microscopy. In wild-type N2 C. elegans, Escherichia coli DH5α, and Vibrio vulnificus 93U204, both of which express the green fluorescence protein, were found intact only proximal to the grinder, while crushed bacterial debris was found in the post-pharyngeal lumen. Nevertheless, the fluorescence was evident throughout the lumen of worm intestines irrespective of whether the bacteria were intact or not. We further investigated the interaction of the bacteria with C. elegans phm-2 mutant, which has a dysfunctional grinder. Both strains of bacteria were found to be intact and accumulated in the pharynx and intestine owing to the defective grinder. The fluorescence intensity of intact bacteria in phm-2 worms was indistinguishable from that of crushed bacterial debris in N2 worms. Therefore, appearance of fluorescence in the C. elegans intestine should not be directly interpreted as successful bacterial colonization in the intestine.

Cyclic AMP-Receptor Protein Activates Aerobactin Receptor IutA Expression in Vibrio vulnificus: Choon-Mee Kim , Seong-Jung Kim , Sung-Heui Shin; J. Microbiol. 2012;50(2):320-325. Published online April 27, 2012; DOI: https://doi.org/10.1007/s12275-012-2056-y

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Abstract: The ferrophilic bacterium Vibrio vulnificus can utilize the siderophore aerobactin of Escherichia coli for iron acquisition via its specific receptor IutA. This siderophore piracy by V. vulnificus may contribute to its survival and proliferation, especially in mixed bacterial environments. In this study, we examined the effects of glucose, cyclic AMP (cAMP), and cAMP-receptor protein (Crp) on iutA expression in V. vulnificus. Glucose dose-dependently repressed iutA expression. A mutation in cya encoding adenylate cyclase required for cAMP synthesis severely repressed iutA expression, and this change was recovered by in trans complementing cya or the addition of exogenous cAMP. Furthermore, a mutation in crp encoding Crp severely repressed iutA expression, and this change was recovered by complementing crp. Accordingly, glucose deprivation under iron-limited conditions is an environmental signal for iutA expression, and Crp functions as an activator that regulates iutA expression in response to glucose availability.

Two Forms of Vibrio vulnificus Metalloprotease VvpE are Secreted via the Type II General Secretion System: Jong Park , So-Yeon Ryu , Choon-Mee Kim , Sung-Heui Shin; J. Microbiol. 2008;46(3):338-343. Published online July 5, 2008; DOI: https://doi.org/10.1007/s12275-008-0058-6

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Abstract: Vibrio vulnificus has been known to secrete one form of metalloprotease VvpE (45 kDa) that is cleaved to 34 kDa-VvpE and 11 kDa-C-terminal propeptide via extracellular autoproteolysis. However, we found that extracellular secretion of both the 34 and 45 kDa forms of VvpE began in the early growth phase; moreover, 34 kDa-VvpE existed as the major form in V. vulnificus cell lysates and culture supernatants. In addition, extracellular secretion of both 34 and 45 kDa-VvpE was blocked by mutation of the pilD gene, which encodes for the type IV leader peptidase/N-methyltransferase of the type II general secretion system, and the blocked VvpE secretion was recovered by in trans-complementation of the wild-type pilD gene. These results indicate that 34 kDa-VvpE is the major form secreted along with 45 kDa-VvpE from the early growth phase via the PilD-mediated type II general secretion system.

Phosphate and Carbon Source Regulation of Alkaline Phosphatase and Phospholipase in Vibrio vulnificus: Wan-Seok Oh , Young-Sun Im , Kyu-Young Yeon , Young-Jun Yoon , Jung-Wan Kim; J. Microbiol. 2007;45(4):311-317.; DOI: https://doi.org/2567 [pii]

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Abstract: 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 LPDMsodium 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.

Identification and Characterization of the Vibrio vulnificus rtxA Essential for Cytotoxicity in vitro and Virulence in Mice: Jeong Hyun Lee , Myung Won Kim , Byoung Sik Kim , Seung Min Kim , Byung Cheol Lee , Tae Sung Kim , Sang Ho Choi; J. Microbiol. 2007;45(2):146-152.; DOI: https://doi.org/2520 [pii]

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Abstract: A mutant exhibiting decreased cytotoxic activity toward INT-407 intestinal epithelial cells and carrying a mutation in the rtx gene cluster that consists of rtxCA and rtxBDE operons was screened from a library of V. vulnificus mutants. The functions of the rtxA gene, assessed by constructing an isogenic mutant and evaluating its phenotypic changes, demonstrated that RtxA is essential for the virulence of V. vulnificus in mice as well as in tissue cultures.

Vibrio vulnificus Metalloprotease VvpE has no Direct Effect on Iron-uptake from Human Hemoglobin: Hui-Yu Sun , Song-Iy Han , Mi-Hwa Choi , Seong-Jung Kim , Choon-Mee Kim , Sung-Heui Shin; J. Microbiol. 2006;44(5):537-547.; DOI: https://doi.org/2443 [pii]

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Abstract: 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.

Swarming Differentiation of Vibrio vulnificus Downregulates the Expression of the vvhBA Hemolysin Gene via the LuxS Quorum-Sensing System: Moon-Young Kim , Ra-Young Park , Mi-Hwa Choi , Hui-Yu Sun , Choon-Mee Kim , Soo-Young Kim , Joon-Haeng Rhee , Sung-Heui Shin; J. Microbiol. 2006;44(2):226-232.; DOI: https://doi.org/2361 [pii]

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Abstract: Swarming has proven to be a good in vitro model for bacterial surface adherence and colonization, and the swarming differentiation of a bacterium has been shown to be coupled with changes in the expression of virulence factors associated with its invasiveness, particularly in the early stages of infection. In this study, we attempted to determine whether the expression of vvhA, which encodes for hemolysin/cytolysin (VvhA), is either upregulated or downregulated during the swarming differentiation of V. vulnificus. The insertional inactivation of vvhA itself exerted no detectable effect on the expression of V. vulnificus swarming motility. However, in our lacZ-fused vvhA transcriptional reporter assay, vvhA expression decreased in swarming V. vulnificus as compared to non-swarming or planktonic V. vulnificus. The reduced expression of vvhA in swarming V. vulnificus increased as a result of the deletional inactivation of luxS, a gene associated with quorum sensing. These results show that vvhA expression in swarming V. vulnificus is downregulated via the activity of the LuxS quorum-sensing system, suggesting that VvhA performs no essential role in the invasiveness of V. vulnificus via the adherence to and colonization on the body surfaces required in the early stages of the infection. However, VvhA may play a significant role in the pathophysiological deterioration occurring after swarming V. vulnificus is differentiated into planktonic V. vulnificus.

Journal Articles

Immunization with Major Outer Membrane Protein of Vibrio vulnificus Elicits Protective Antibodies in a Murine Model: Cho-Rok Jung , Min-Jung Park , Moon-Soo Heo; J. Microbiol. 2005;43(5):437-442.; DOI: https://doi.org/2278 [pii]

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Abstract: Sera from rabbits were infected with Vibrio vulnificus containing an antibody against major outer membrane protein (MOMP). MOMP of V. vulnificus ATCC 27562 were isolated and purified by Sarkosyl and TritonX-100 dual treatment. Molecular size of MOMP was identified as 36-kDa on 13% SDS-PAGE. The sequence of the first 26 amino acid residues from the N-terminal end of the protein is AELYNQDGTSLDMGGRAEARLSMKDG , which is a perfect match with OmpU of V. vulnificus CMCP6 and YJ016. MOMP specific IgM and IgG were investigated in groups of mice. The group of mice immunized with MOMP and Alum showed higher levels of IgG2b than the group immunized with only MOMP. Vaccination with MOMP resulted in protective antibodies in the mouse infection experiment.

Changes in Membrane Fatty Acid Composition during Entry of Vibrio vulnificus into the Viable But Nonculturable State: Ashley P. Day , James D. Oliver; J. Microbiol. 2004;42(2):69-73.; DOI: https://doi.org/2043 [pii]

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Abstract: Vibrio vulnificus, a Gram-negative bacterium found in estuarine waters, is responsible for over 95% of all seafood-related deaths in the United States. As a result of a temperature downshift to 5^oC, this organism enters the viable but nonculturable (VBNC) state. Changes in the membrane fatty acid (FA) composition of V. vulnificus may be a contributing factor to the ability of this organism to enter into and survive in the VBNC state. This hypothesis was tested by incubating the organism at 5^oC in artificial sea water and analyzing the cells’ FAs during the initial hours of temperature and nutrient downshift. Prior to downshift, the predominant FAs were 16:0, 16:1 and 18:0. During the first four hours of downshift, statistically significant changes occurred in 15:0, 16:1, 16:0, 17:0, and 18:0. These results indicate that changes in FA composition occur prior to entry of V. vulnificus into the VBNC state, suggesting that the ability to maintain membrane fluidity may be a factor in this physiological response. Cells in which fatty acid synthesis was inhibited did not survive, indicating that active fatty acid metabolism is essential for entry of cells into the VBNC state.

Rapid Identification of Vibrio vulnificus in Seawater by Real-Time Quantitative TaqMan PCR: Hye-Young Wang , Geon-Hyoung Lee; J. Microbiol. 2003;41(4):320-326.

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Abstract: In order to identify Vibrio vulnificus in the Yellow Sea near Gunsan, Korea during the early and late summers, the efficiency of the real-time quantitative TaqMan PCR was compared to the efficiency of the conventional PCR and Biolog identification system^TM. Primers and a probe were designed from the hemolysin/cytolysin gene sequence of V. vulnificus strains. The number of positive detections by real-time quantitative TaqMan PCR, conventional PCR, and the Biolog identification system from seawater were 53 (36.8%), 36 (25%), and 10 strains (6.9%), respectively, among 144 samples collected from Yellow Sea near Gunsan, Korea. Thus, the detection method of the real-time quantitative TaqMan PCR assay was more effective in terms of accuracy than that of the conventional PCR and Biolog system. Therefore, our results showed that the real-time TaqMan probe and the primer set developed in this study can be applied successfully as a rapid screening tool for the detection of V. vulnificus.

Molecular Pathogenesis of Vibrio vulnificus: Paul A. Gulig , Keri L. Bourdage , Angela M. Starks; J. Microbiol. 2005;43(1):118-131.

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Abstract: Vibrio vulnificus is an opportunistic pathogen of humans that has the capability of causing rare, yet devastating disease. The bacteria are naturally present in estuarine environments and frequently contaminate seafoods. Within days of consuming uncooked, contaminated seafood, predisposed individuals can succumb to sepsis. Additionally, in otherwise healthy people, V. vulnificus causes wound infection that can require amputation or lead to sepsis. These diseases share the characteristics that the bacteria multiply extremely rapidly in host tissues and cause extensive damage. Despite the analysis of virulence for over 20 years using a combination of animal and cell culture models, surprisingly little is known about the mechanisms by which V. vulnificus causes disease. This is in part because of differences observed using animal models that involve infection with bacteria versus injection of toxins. However, the increasing use of genetic analysis coupled with detailed animal models is revealing new insight into the pathogenesis of V. vulnificus disease.

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