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Environmental Reservoirs of Pathogenic Vibrio spp. and Their Role in Disease: The List Keeps Expanding. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1404:99-126. [PMID: 36792873 DOI: 10.1007/978-3-031-22997-8_6] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Vibrio species are natural inhabitants of aquatic environments and have complex interactions with the environment that drive the evolution of traits contributing to their survival. These traits may also contribute to their ability to invade or colonize animal and human hosts. In this review, we attempt to summarize the relationships of Vibrio spp. with other organisms in the aquatic environment and discuss how these interactions could potentially impact colonization of animal and human hosts.
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2
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D’Souza C, Prithvisagar KS, Deekshit VK, Karunasagar I, Karunasagar I, Kumar BK. Exploring the Pathogenic Potential of Vibrio vulnificus Isolated from Seafood Harvested along the Mangaluru Coast, India. Microorganisms 2020; 8:microorganisms8070999. [PMID: 32635463 PMCID: PMC7409051 DOI: 10.3390/microorganisms8070999] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/10/2020] [Accepted: 05/21/2020] [Indexed: 12/19/2022] Open
Abstract
It has been observed that not all strains of Vibrio vulnificus are virulent. Determining the virulence of strains that are frequently present in seafood is of significance for ensuring seafood safety. This study is an attempt to predict the virulence of seafood-borne V. vulnificus isolated along the Mangaluru Coast, India. The isolates tested possessed a vcgC gene sequence with high similarity to that in the clinical strain. Transcriptional analysis of core virulence genes in seafood isolate E4010 showed the phenomenon of contact-mediated expression of rtxA1 which correlated well with the actin disintegration and cytotoxicity. These results suggest that the seafood isolates tested in this study possess a functional RtxA1 which could help in initiating the infection. However, other putative virulence genes such as vvpE encoding an extracellular protease, vvhA encoding hemolysin, flp encoding tad pilin and ompU encoding fibronectin-binding protein were also constitutively expressed. Virulence-associated attributes such as cytotoxicity and adherence matched the response of the clinical strain (p > 0.05). On the other hand, the environmental strains showed higher serum sensitivity compared with the clinical strain. These findings show that the part of virulence attributes required for the disease process might be intact in these isolates.
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Affiliation(s)
- Caroline D’Souza
- Division of Infectious Diseases, Nitte University Centre for Science Education and Research, Nitte (Deemed to be University), Deralakatte, Mangalore 575018, India; (C.D.); (K.S.P.); (V.K.D.); (I.K.)
| | - Kattapuni Suresh Prithvisagar
- Division of Infectious Diseases, Nitte University Centre for Science Education and Research, Nitte (Deemed to be University), Deralakatte, Mangalore 575018, India; (C.D.); (K.S.P.); (V.K.D.); (I.K.)
| | - Vijay Kumar Deekshit
- Division of Infectious Diseases, Nitte University Centre for Science Education and Research, Nitte (Deemed to be University), Deralakatte, Mangalore 575018, India; (C.D.); (K.S.P.); (V.K.D.); (I.K.)
| | - Indrani Karunasagar
- Division of Infectious Diseases, Nitte University Centre for Science Education and Research, Nitte (Deemed to be University), Deralakatte, Mangalore 575018, India; (C.D.); (K.S.P.); (V.K.D.); (I.K.)
| | - Iddya Karunasagar
- Nitte (Deemed to be University), University Enclave, Medical Sciences Complex, Deralakatte, Mangaluru 575018, India;
| | - Ballamoole Krishna Kumar
- Division of Infectious Diseases, Nitte University Centre for Science Education and Research, Nitte (Deemed to be University), Deralakatte, Mangalore 575018, India; (C.D.); (K.S.P.); (V.K.D.); (I.K.)
- Correspondence: ; Tel.: +91-824-220-4292 (ext. 201)
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Arunkumar M, LewisOscar F, Thajuddin N, Pugazhendhi A, Nithya C. In vitro and in vivo biofilm forming Vibrio spp: A significant threat in aquaculture. Process Biochem 2020. [DOI: 10.1016/j.procbio.2020.04.029] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Abstract
The type II secretion system (T2SS) delivers toxins and a range of hydrolytic enzymes, including proteases, lipases, and carbohydrate-active enzymes, to the cell surface or extracellular space of Gram-negative bacteria. Its contribution to survival of both extracellular and intracellular pathogens as well as environmental species of proteobacteria is evident. This dynamic, multicomponent machinery spans the entire cell envelope and consists of a cytoplasmic ATPase, several inner membrane proteins, a periplasmic pseudopilus, and a secretin pore embedded in the outer membrane. Despite the trans-envelope configuration of the T2S nanomachine, proteins to be secreted engage with the system first once they enter the periplasmic compartment via the Sec or TAT export system. Thus, the T2SS is specifically dedicated to their outer membrane translocation. The many sequence and structural similarities between the T2SS and type IV pili suggest a common origin and argue for a pilus-mediated mechanism of secretion. This minireview describes the structures, functions, and interactions of the individual T2SS components and the general architecture of the assembled T2SS machinery and briefly summarizes the transport and function of a growing list of T2SS exoproteins. Recent advances in cryo-electron microscopy, which have led to an increased understanding of the structure-function relationship of the secretin channel and the pseudopilus, are emphasized.
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Yamazaki K, Kashimoto T, Morita M, Kado T, Matsuda K, Yamasaki M, Ueno S. Identification of in vivo Essential Genes of Vibrio vulnificus for Establishment of Wound Infection by Signature-Tagged Mutagenesis. Front Microbiol 2019; 10:123. [PMID: 30774628 PMCID: PMC6367243 DOI: 10.3389/fmicb.2019.00123] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 01/18/2019] [Indexed: 01/22/2023] Open
Abstract
Vibrio vulnificus can cause severe necrotic lesions within a short time. Recently, it has been reported that the numbers of wound infection cases in healthy hosts are increasing, for which surgical procedures are essential in many instances to eliminate the pathogen owing to its rapid proliferation. However, the mechanisms by which V. vulnificus can achieve wound infection in healthy hosts have not been elucidated. Here, we advance a systematic understanding of V. vulnificus wound infection through genome-wide identification of the relevant genes. Signature-tagged mutagenesis (STM) has been developed to identify functions required for the establishment of infection including colonization, rapid proliferation, and pathogenicity. Previously, STM had been regarded to be unsuitable for negative selection to detect the virulence genes of V. vulnificus owing to the low colonization and proliferation ability of this pathogen in the intestinal tract and systemic circulation. Alternatively, we successfully identified the virulence genes by applying STM to a murine model of wound infection. We examined a total of 5418 independent transposon insertion mutants by signature-tagged transposon mutagenesis and detected 71 clones as attenuated mutants consequent to disruption of genes by the insertion of a transposon. This is the first report demonstrating that the pathogenicity of V. vulnificus during wound infection is highly dependent on its characteristics: flagellar-based motility, siderophore-mediated iron acquisition system, capsular polysaccharide, lipopolysaccharide, and rapid chromosome partitioning. In particular, these functions during the wound infection process and are indispensable for proliferation in healthy hosts. Our results may thus allow the potential development of new strategies and reagents to control the proliferation of V. vulnificus and prevent human infections.
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Affiliation(s)
- Kohei Yamazaki
- Laboratory of Veterinary Public Health, School of Veterinary Medicine, Kitasato University, Towada, Japan
| | - Takashige Kashimoto
- Laboratory of Veterinary Public Health, School of Veterinary Medicine, Kitasato University, Towada, Japan
| | - Mio Morita
- Laboratory of Veterinary Public Health, School of Veterinary Medicine, Kitasato University, Towada, Japan
| | - Takehiro Kado
- Laboratory of Veterinary Public Health, School of Veterinary Medicine, Kitasato University, Towada, Japan
| | - Kaho Matsuda
- Laboratory of Veterinary Public Health, School of Veterinary Medicine, Kitasato University, Towada, Japan
| | - Moeko Yamasaki
- Laboratory of Veterinary Public Health, School of Veterinary Medicine, Kitasato University, Towada, Japan
| | - Shunji Ueno
- Laboratory of Veterinary Public Health, School of Veterinary Medicine, Kitasato University, Towada, Japan
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Wang N, Liu J, Pang M, Wu Y, Awan F, Liles MR, Lu C, Liu Y. Diverse roles of Hcp family proteins in the environmental fitness and pathogenicity of Aeromonas hydrophila Chinese epidemic strain NJ-35. Appl Microbiol Biotechnol 2018; 102:7083-7095. [PMID: 29862449 DOI: 10.1007/s00253-018-9116-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 05/14/2018] [Accepted: 05/18/2018] [Indexed: 01/19/2023]
Abstract
The type VI secretion system (T6SS) has been considered as a crucial factor in bacterial competition and virulence. The hemolysin co-regulated protein (Hcp) is the hallmark of T6SS. The secretion of Hcp in Aeromonas hydrophila Chinese epidemic strain NJ-35 indicated a functional T6SS. In this study, three copies of the hcp gene were identified in the genome of strain NJ-35. We targeted these Hcp family proteins for generating deletion mutants. These mutants showed varying levels in Hcp production, the interaction with other bacteria or eukaryotic cells, and bacterial virulence. Hcp1 was necessary for T6SS assembly and played a predominant role in the bacterial competition; Hcp2 negatively functioned in the biofilm formation and bacterial adhesion and was more involved in the A. hydrophila virulence in zebrafish and survival against the predation of Tetrahymena, and Hcp3 positively influenced the biofilm formation and bacterial adhesion. These findings illustrate that the T6SS of A. hydrophila NJ-35 is active, and the three Hcp family proteins take part in different processes in environmental adaptation and virulence of this bacterium. This study will provide valuable insights into our understanding of microbial interactions and thus contribute to a broader effort to manipulate these interactions for therapeutic or environmental benefit.
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Affiliation(s)
- Nannan Wang
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Jin Liu
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Maoda Pang
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.,Key Lab of Food Quality and Safety of Jiangsu Province-State Key Laboratory Breeding Base, Institute of Food Safety and Nutrition, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Yafeng Wu
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.,Jiangsu Center for Control and Prevention of Aquatic Animal Infectious Diseases, Nanjing, China
| | - Furqan Awan
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Mark R Liles
- Department of Biological Sciences, Auburn University, Auburn, USA
| | - Chengping Lu
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Yongjie Liu
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.
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Xu Z, Puranik R, Hu J, Xu H, Han D. Complete genome sequence of Thermotoga sp. strain RQ7. Stand Genomic Sci 2017; 12:62. [PMID: 29046741 PMCID: PMC5637354 DOI: 10.1186/s40793-017-0271-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 09/21/2017] [Indexed: 12/26/2022] Open
Abstract
Thermotoga sp. strain RQ7 is a member of the family Thermotogaceae in the order Thermotogales. It is a Gram negative, hyperthermophilic, and strictly anaerobic bacterium. It grows on diverse simple and complex carbohydrates and can use protons as the final electron acceptor. Its complete genome is composed of a chromosome of 1,851,618 bp and a plasmid of 846 bp. The chromosome contains 1906 putative genes, including 1853 protein coding genes and 53 RNA genes. The genetic features pertaining to various lateral gene transfer mechanisms are analyzed. The genome carries a complete set of putative competence genes, 8 loci of CRISPRs, and a deletion of a well-conserved Type II R-M system.
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Affiliation(s)
- Zhaohui Xu
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403 USA
| | - Rutika Puranik
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403 USA
| | - Junxi Hu
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403 USA
- School of Life Sciences, Minnan Normal University, 36 Xianqianzhi Street, Zhangzhou, Fujian 363000 China
| | - Hui Xu
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403 USA
| | - Dongmei Han
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403 USA
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8
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Yong D, Tee KK, Yin WF, Chan KG. Characterization and Comparative Overview of Complete Sequences of the First Plasmids of Pandoraea across Clinical and Non-clinical Strains. Front Microbiol 2016; 7:1606. [PMID: 27790203 PMCID: PMC5064223 DOI: 10.3389/fmicb.2016.01606] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 09/26/2016] [Indexed: 11/25/2022] Open
Abstract
To date, information on plasmid analysis in Pandoraea spp. is scarce. To address the gap of knowledge on this, the complete sequences of eight plasmids from Pandoraea spp. namely Pandoraea faecigallinarum DSM 23572T (pPF72-1, pPF72-2), Pandoraea oxalativorans DSM 23570T (pPO70-1, pPO70-2, pPO70-3, pPO70-4), Pandoraea vervacti NS15 (pPV15) and Pandoraea apista DSM 16535T (pPA35) were studied for the first time in this study. The information on plasmid sequences in Pandoraea spp. is useful as the sequences did not match any known plasmid sequence deposited in public databases. Replication genes were not identified in some plasmids, a situation that has led to the possibility of host interaction involvement. Some plasmids were also void of par genes and intriguingly, repA gene was also not discovered in these plasmids. This further leads to the hypothesis of host-plasmid interaction. Plasmid stabilization/stability protein-encoding genes were observed in some plasmids but were not established for participating in plasmid segregation. Toxin-antitoxin systems MazEF, VapBC, RelBE, YgiT-MqsR, HigBA, and ParDE were identified across the plasmids and their presence would improve plasmid maintenance. Conjugation genes were identified portraying the conjugation ability amongst Pandoraea plasmids. Additionally, we found a shared region amongst some of the plasmids that consists of conjugation genes. The identification of genes involved in replication, segregation, toxin-antitoxin systems and conjugation, would aid the design of drugs to prevent the survival or transmission of plasmids carrying pathogenic properties. Additionally, genes conferring virulence and antibiotic resistance were identified amongst the plasmids. The observed features in the plasmids shed light on the Pandoraea spp. as opportunistic pathogens.
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Affiliation(s)
- Delicia Yong
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya Kuala Lumpur, Malaysia
| | - Kok Keng Tee
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya Kuala Lumpur, Malaysia
| | - Wai-Fong Yin
- Division of Genetics and Molecular Biology, Faculty of Science, Institute of Biological Sciences, University of Malaya Kuala Lumpur, Malaysia
| | - Kok-Gan Chan
- Division of Genetics and Molecular Biology, Faculty of Science, Institute of Biological Sciences, University of Malaya Kuala Lumpur, Malaysia
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9
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Oliva Chávez AS, Fairman JW, Felsheim RF, Nelson CM, Herron MJ, Higgins L, Burkhardt NY, Oliver JD, Markowski TW, Kurtti TJ, Edwards TE, Munderloh UG. An O-Methyltransferase Is Required for Infection of Tick Cells by Anaplasma phagocytophilum. PLoS Pathog 2015; 11:e1005248. [PMID: 26544981 PMCID: PMC4636158 DOI: 10.1371/journal.ppat.1005248] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 10/03/2015] [Indexed: 12/16/2022] Open
Abstract
Anaplasma phagocytophilum, the causative agent of Human Granulocytic Anaplasmosis (HGA), is an obligately intracellular α-proteobacterium that is transmitted by Ixodes spp ticks. However, the pathogen is not transovarially transmitted between tick generations and therefore needs to survive in both a mammalian host and the arthropod vector to complete its life cycle. To adapt to different environments, pathogens rely on differential gene expression as well as the modification of proteins and other molecules. Random transposon mutagenesis of A. phagocytophilum resulted in an insertion within the coding region of an o-methyltransferase (omt) family 3 gene. In wild-type bacteria, expression of omt was up-regulated during binding to tick cells (ISE6) at 2 hr post-inoculation, but nearly absent by 4 hr p.i. Gene disruption reduced bacterial binding to ISE6 cells, and the mutant bacteria that were able to enter the cells were arrested in their replication and development. Analyses of the proteomes of wild-type versus mutant bacteria during binding to ISE6 cells identified Major Surface Protein 4 (Msp4), but also hypothetical protein APH_0406, as the most differentially methylated. Importantly, two glutamic acid residues (the targets of the OMT) were methyl-modified in wild-type Msp4, whereas a single asparagine (not a target of the OMT) was methylated in APH_0406. In vitro methylation assays demonstrated that recombinant OMT specifically methylated Msp4. Towards a greater understanding of the overall structure and catalytic activity of the OMT, we solved the apo (PDB_ID:4OA8), the S-adenosine homocystein-bound (PDB_ID:4OA5), the SAH-Mn2+ bound (PDB_ID:4PCA), and SAM- Mn2+ bound (PDB_ID:4PCL) X-ray crystal structures of the enzyme. Here, we characterized a mutation in A. phagocytophilum that affected the ability of the bacteria to productively infect cells from its natural vector. Nevertheless, due to the lack of complementation, we cannot rule out secondary mutations. Since its discovery in 1994, Human Granulocytic Anaplasmosis (HGA) has become the second most commonly diagnosed tick-borne disease in the US, and it is gaining importance in several countries in Europe. HGA is caused by Anaplasma phagocytophilum, a bacterium transmitted by black-legged ticks and their relatives. Whereas several of the molecules and processes leading to infection of human cells have been identified, little is known about their counterparts in the tick. We analyzed the effects of a mutation in a gene encoding an o-methyltransferase that is involved in methylation of an outer membrane protein. The mutation of the OMT appears to be important for the ability of A. phagocytophilum to adhere to, invade, and replicate in tick cells. Several tests including binding assays, microscopic analysis of the infection cycle within tick cells, gene expression assays, and biochemical assays using recombinant OMT strongly suggested that the mutation of the o-methyltransferase gene arrested the growth and development of this bacterium within tick cells. Proteomic analyses identified several possible OMT substrates, and in vitro methylation assays using recombinant o-methyltransferase identified an outer membrane protein, Msp4, as a specifically methyl-modified target. Our results indicated that methylation was important for infection of tick cells by A. phagocytophilum, and suggested possible strategies to block transmission of this emerging pathogen. The solved crystal structure of the o-methyltransferase will further stimulate the search for small molecule inhibitors that could break the tick transmission cycle of A. phagocytophilum in nature.
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Affiliation(s)
- Adela S. Oliva Chávez
- Department of Entomology, University of Minnesota, Saint Paul, Minnesota, United States of America
- * E-mail:
| | - James W. Fairman
- Emerald Bio, Bainbridge Island, Washington, United States of America
- Seattle Structural Genomics Center for Infectious Disease, Seattle, Washington, United States of America
| | - Roderick F. Felsheim
- Department of Entomology, University of Minnesota, Saint Paul, Minnesota, United States of America
| | - Curtis M. Nelson
- Department of Entomology, University of Minnesota, Saint Paul, Minnesota, United States of America
| | - Michael J. Herron
- Department of Entomology, University of Minnesota, Saint Paul, Minnesota, United States of America
| | - LeeAnn Higgins
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Nicole Y. Burkhardt
- Department of Entomology, University of Minnesota, Saint Paul, Minnesota, United States of America
| | - Jonathan D. Oliver
- Department of Entomology, University of Minnesota, Saint Paul, Minnesota, United States of America
| | - Todd W. Markowski
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Timothy J. Kurtti
- Department of Entomology, University of Minnesota, Saint Paul, Minnesota, United States of America
| | - Thomas E. Edwards
- Emerald Bio, Bainbridge Island, Washington, United States of America
- Seattle Structural Genomics Center for Infectious Disease, Seattle, Washington, United States of America
| | - Ulrike G. Munderloh
- Department of Entomology, University of Minnesota, Saint Paul, Minnesota, United States of America
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Kashimoto T, Iwasaki C, Gojo M, Sugiyama H, Yoshioka K, Yamamoto Y, Okamura M, Susa N, Ueno S. Vibrio vulnificus detected in the spleen leads to fatal outcome in a mouse oral infection model. FEMS Microbiol Lett 2015; 362:fnv005. [PMID: 25790509 DOI: 10.1093/femsle/fnv005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Vibrio vulnificus causes rapid disseminating septicemia by oral infection in infected individuals who have an underlying disease, especially chronic liver diseases. Although the elucidation of specific risk factors for V. vulnificus infection in patients with liver diseases is of urgent importance, no appropriate experimental animal model that mimics the liver diseases in this bacterial infection has been available so far. To discover these risk factors, we generated a liver disordered mouse by performing bile duct ligation (BDL). Hepatitis developed in the BDL mice; however, this did not affect mortality in mice after orogastric administration of V. vulnificus, suggesting that the liver disorders caused by the BDL were not risk factors for V. vulnificus septicemia. When the dead and surviving mice were compared, V. vulnificus could be detected from the spleen only in the dead group. Furthermore, significantly higher numbers of V. vulnificus were detected from the intestines in the dead group than in the surviving group ( P < 0.001). These findings suggested that proliferation of the challenge inoculum in the intestine was needed for the oral infection with V. vulnificus, and that the elimination of V. vulnificus in the liver and/or spleen plays a critical role in survival of the host.
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Affiliation(s)
- Takashige Kashimoto
- Laboratory of Veterinary Public Health, School of Veterinary Medicine, Kitasato University, Higashi 23-35-1, Towada, Aomori 034-8628, Japan
| | - Chiemi Iwasaki
- Laboratory of Veterinary Public Health, School of Veterinary Medicine, Kitasato University, Higashi 23-35-1, Towada, Aomori 034-8628, Japan
| | - Masanori Gojo
- Laboratory of Veterinary Public Health, School of Veterinary Medicine, Kitasato University, Higashi 23-35-1, Towada, Aomori 034-8628, Japan
| | - Hiroyuki Sugiyama
- Laboratory of Veterinary Public Health, School of Veterinary Medicine, Kitasato University, Higashi 23-35-1, Towada, Aomori 034-8628, Japan
| | - Kazuki Yoshioka
- Laboratory of Veterinary Anatomy, School of Veterinary Medicine, Kitasato University, 23-35-1 Higashi, Towada, Aomori 034-8628, Japan
| | - Yuji Yamamoto
- Laboratory of Biomolecular Function, School of Veterinary Medicine, Kitasato University, 23-35-1 Higashi, Towada, Aomori 034-8628, Japan
| | - Masashi Okamura
- Laboratory of Zoonoses, School of Veterinary Medicine, Kitasato University, Higashi 23-35-1, Towada Aomori 034-8628, Japan
| | - Nobuyuki Susa
- Laboratory of Veterinary Public Health, School of Veterinary Medicine, Kitasato University, Higashi 23-35-1, Towada, Aomori 034-8628, Japan
| | - Shunji Ueno
- Laboratory of Veterinary Public Health, School of Veterinary Medicine, Kitasato University, Higashi 23-35-1, Towada, Aomori 034-8628, Japan
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Role of anaerobiosis in capsule production and biofilm formation in Vibrio vulnificus. Infect Immun 2014; 83:551-9. [PMID: 25404024 DOI: 10.1128/iai.02559-14] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Vibrio vulnificus, a pervasive human pathogen, can cause potentially fatal septicemia after consumption of undercooked seafood. Biotype 1 strains of V. vulnificus are most commonly associated with human infection and are separated into two genotypes, clinical (C) and environmental (E), based on the virulence-correlated gene. For ingestion-based vibriosis to occur, this bacterium must be able to withstand multiple conditions as it traverses the gastrointestinal tract and ultimately gains entry into the bloodstream. One such condition, anoxia, has yet to be extensively researched in V. vulnificus. We investigated the effect of oxygen availability on capsular polysaccharide (CPS) production and biofilm formation in this bacterium, both of which are thought to be important for disease progression. We found that lack of oxygen elicits a reduction in both CPS and biofilm formation in both genotypes. This is further supported by the finding that pilA, pilD, and mshA genes, all of which encode type IV pilin proteins that aid in attachment to surfaces, were downregulated during anaerobiosis. Surprisingly, E-genotypes exhibited distinct differences in gene expression levels of capsule and attachment genes compared to C-genotypes, both aerobically and anaerobically. The importance of understanding these disparities may give insight into the observed differences in environmental occurrence and virulence potential between these two genotypes of V. vulnificus.
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Implications of chitin attachment for the environmental persistence and clinical nature of the human pathogen Vibrio vulnificus. Appl Environ Microbiol 2013; 80:1580-7. [PMID: 24362430 DOI: 10.1128/aem.03811-13] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Vibrio vulnificus naturally inhabits a variety of aquatic organisms, including oysters, and is the leading cause of seafood-related death in the United States. Strains of this bacterium are genetically classified into environmental (E) and clinical (C) genotypes, which correlate with source of isolation. E-genotype strains integrate into marine aggregates more efficiently than do C-genotype strains, leading to a greater uptake of strains of this genotype by oysters feeding on these aggregates. The causes of this increased integration of E-type strains into marine "snow" have not been demonstrated. Here, we further investigate the physiological and genetic causalities for this genotypic heterogeneity by examining the ability of strains of each genotype to attach to chitin, a major constituent of marine snow. We found that E-genotype strains attach to chitin with significantly greater efficiency than do C-genotype strains when incubated at 20°C. Type IV pili were implicated in chitin adherence, and even in the absence of chitin, the expression level of type IV pilin genes (pilA, pilD, and mshA) was found to be inherently higher by E genotypes than by C genotypes. In contrast, the level of expression of N-acetylglucosamine binding protein A (gbpA) was significantly higher in C-genotype strains. Interestingly, incubation at a clinically relevant temperature (37°C) resulted in a significant increase in C-genotype attachment to chitin, which subsequently provided a protective effect against exposure to acid or bile, thus offering a clue into their increased incidence in human infections. This study suggests that C- and E-genotype strains have intrinsically divergent physiological programs, which may help explain the observed differences in the ecology and pathogenic potential between these two genotypes.
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Bisharat N, Bronstein M, Korner M, Schnitzer T, Koton Y. Transcriptome profiling analysis of Vibrio vulnificus during human infection. MICROBIOLOGY-SGM 2013; 159:1878-1887. [PMID: 23782800 DOI: 10.1099/mic.0.067900-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Vibrio vulnificus is a waterborne pathogen that was responsible for an outbreak of severe soft-tissue infections among fish farmers and fish consumers in Israel. Several factors have been shown to be associated with virulence. However, the transcriptome profile of the pathogen during human infection has not been determined yet. We compared the transcriptome profile, using RNA sequencing, of a human-pathogenic strain harvested directly from tissue of a patient suffering from severe soft-tissue infection with necrotizing fasciitis, with the same strain and three other environmental strains grown in vitro. The five sequenced libraries were aligned to the reference genomes of V. vulnificus strains CMCP6 and YJ016. Approximately 47.8 to 62.3 million paired-end raw reads were generated from the five runs. Nearly 84 % of the genome was covered by reads from at least one of the five runs, suggesting that nearly 16 % of the genome is not transcribed or is transcribed at low levels. We identified 123 genes that were differentially expressed during the acute phase of infection. Sixty-three genes were mapped to the large chromosome, 47 genes mapped to the small chromosome and 13 genes mapped to the YJ016 plasmid. The 123 genes fell into a variety of functional categories including transcription, signal transduction, cell motility, carbohydrate metabolism, intracellular trafficking and cell envelope biogenesis. Among the genes differentially expressed during human infection we identified genes encoding bacterial toxin (RtxA1) and genes involved in flagellar components, Flp-coding region, GGDEF family protein, iron acquisition system and sialic acid metabolism.
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Affiliation(s)
- Naiel Bisharat
- Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel.,Department of Medicine D, Emek Medical Center, Afula, Israel
| | - Michal Bronstein
- Center for Genomic Technologies, Alexander Silberman Institute of Life Sciences, Hebrew University, Jerusalem, Israel
| | - Mira Korner
- Center for Genomic Technologies, Alexander Silberman Institute of Life Sciences, Hebrew University, Jerusalem, Israel
| | - Temima Schnitzer
- Goldyne Savad Institute of Gene Therapy, Hadassah Medical Center, Hebrew University, Jerusalem, Israel
| | - Yael Koton
- Department of Medicine D, Emek Medical Center, Afula, Israel
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Johnson CN. Fitness factors in vibrios: a mini-review. MICROBIAL ECOLOGY 2013; 65:826-851. [PMID: 23306394 DOI: 10.1007/s00248-012-0168-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 12/13/2012] [Indexed: 06/01/2023]
Abstract
Vibrios are Gram-negative curved bacilli that occur naturally in marine, estuarine, and freshwater systems. Some species include human and animal pathogens, and some vibrios are necessary for natural systems, including the carbon cycle and osmoregulation. Countless in vivo and in vitro studies have examined the interactions between vibrios and their environment, including molecules, cells, whole animals, and abiotic substrates. Many studies have characterized virulence factors, attachment factors, regulatory factors, and antimicrobial resistance factors, and most of these factors impact the organism's fitness regardless of its external environment. This review aims to identify common attributes among factors that increase fitness in various environments, regardless of whether the environment is an oyster, a rabbit, a flask of immortalized mammalian cells, or a planktonic chitin particle. This review aims to summarize findings published thus far to encapsulate some of the basic similarities among the many vibrio fitness factors and how they frame our understanding of vibrio ecology. Factors representing these similarities include hemolysins, capsular polysaccharides, flagella, proteases, attachment factors, type III secretion systems, chitin binding proteins, iron acquisition systems, and colonization factors.
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Affiliation(s)
- Crystal N Johnson
- Department of Environmental Sciences, Louisiana State University, Baton Rouge, LA, USA.
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Lee HJ, Kim JA, Lee MA, Park SJ, Lee KH. 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. Mol Microbiol 2013; 88:813-26. [PMID: 23560801 DOI: 10.1111/mmi.12224] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/01/2013] [Indexed: 11/29/2022]
Abstract
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.
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Affiliation(s)
- Hyun-Jung Lee
- Department of Life Science and Interdisciplinary Program of Integrated Biotechnology, Sogang University, Seoul 121-742, Korea
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Persistence of Vibrio parahaemolyticus in the Pacific oyster, Crassostrea gigas, is a multifactorial process involving pili and flagella but not type III secretion systems or phase variation. Appl Environ Microbiol 2013; 79:3303-5. [PMID: 23475619 DOI: 10.1128/aem.00314-13] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Vibrio parahaemolyticus can resist oyster depuration, suggesting that it possesses specific factors for persistence. We show that type I pili, type IV pili, and both flagellar systems contribute to V. parahaemolyticus persistence in Pacific oysters whereas type III secretion systems and phase variation do not.
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Aagesen AM, Häse CC. Sequence analyses of type IV pili from Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus. MICROBIAL ECOLOGY 2012; 64:509-524. [PMID: 22383120 DOI: 10.1007/s00248-012-0021-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 02/03/2012] [Indexed: 05/31/2023]
Abstract
Bacterial surface structures called pili have been studied extensively for their role as possible colonization factors. Most sequenced Vibrio genomes predict a variety of pili genes in these organisms, including several types of type IV pili. In particular, the mannose-sensitive hemagglutinin (MSHA) and the PilA pili, also known as the chitin-regulated pilus (ChiRP), are type IVa pili commonly found in Vibrio genomes and have been shown to play a role in the colonization of Vibrio species in the environment and/or host tissue. Here, we report sequence comparisons of two type IVa pilin subunit genes, mshA and pilA, and their corresponding amino acid sequences, for several strains from the three main human pathogenic Vibrio species, V. cholerae, V. parahaemolyticus, and V. vulnificus. We identified specific groupings of these two genes in V. cholerae, whereas V. parahaemolyticus and V. vulnificus strains had no apparent allelic clusters, and these genes were strikingly divergent. These results were compared with other genes from the MSHA and PilA operons as well as another Vibrio pili from the type IVb group, the toxin co-regulated pilus (TCP) from V. cholerae. Our data suggest that a selective pressure exists to cause these strains to vary their MSHA and PilA pilin subunits. Interestingly, V. cholerae strains possessing TCP have the same allele for both mshA and pilA. In contrast, V. cholerae isolates without TCP have polymorphisms in their mshA and pilA sequences similar to what was observed for both V. parahaemolyticus and V. vulnificus. This data suggests a possible linkage between host interactions and maintaining a highly conserved type IV pili sequence in V. cholerae. Although the mechanism underlying this intriguing diversity has yet to be elucidated, our analyses are an important first step towards gaining insights into the various aspects of Vibrio ecology.
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Affiliation(s)
- Alisha M Aagesen
- Department of Biomedical Sciences, Oregon State University, Corvallis, OR 97331, USA
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Hwang W, Lee NY, Kim J, Lee MA, Kim KS, Lee KH, Park SJ. Functional characterization of EpsC, a component of the type II secretion system, in the pathogenicity of Vibrio vulnificus. Infect Immun 2011; 79:4068-80. [PMID: 21788383 PMCID: PMC3187239 DOI: 10.1128/iai.05351-11] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 07/16/2011] [Indexed: 01/22/2023] Open
Abstract
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.
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Affiliation(s)
- Won Hwang
- Department of Environmental Medical Biology, Institute of Tropical Medicine, Post Brain Korea 21 Program, Yonsei University College of Medicine, Seoul 120-752
- Department of Life Science, Sogang University, Seoul 121-741
| | - Na Yeon Lee
- Department of Environmental Medical Biology, Institute of Tropical Medicine, Post Brain Korea 21 Program, Yonsei University College of Medicine, Seoul 120-752
| | - Juri Kim
- Department of Environmental Medical Biology, Institute of Tropical Medicine, Post Brain Korea 21 Program, Yonsei University College of Medicine, Seoul 120-752
| | - Mi-Ae Lee
- Department of Environmental Sciences, Hankuk University of Foreign Studies, Yongin 449-741, Republic of Korea
| | - Kun-Soo Kim
- Department of Life Science, Sogang University, Seoul 121-741
| | - Kyu-Ho Lee
- Department of Environmental Sciences, Hankuk University of Foreign Studies, Yongin 449-741, Republic of Korea
| | - Soon-Jung Park
- Department of Environmental Medical Biology, Institute of Tropical Medicine, Post Brain Korea 21 Program, Yonsei University College of Medicine, Seoul 120-752
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Lee TH, Kim YR, Rhee JH, Kim JH, Woo HR, Chung KM. Characterization of monoclonal antibodies targeting the RtxA1 toxin of Vibrio vulnificus. Process Biochem 2011. [DOI: 10.1016/j.procbio.2011.04.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Identification and characterization of a novel serine protease, VvpS, that contains two functional domains and is essential for autolysis of Vibrio vulnificus. J Bacteriol 2011; 193:3722-32. [PMID: 21642466 DOI: 10.1128/jb.00314-11] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Little is known about the molecular mechanism for autolysis of Gram-negative bacteria. In the present study, we identified the vvpS gene encoding a serine protease, VvpS, from Vibrio vulnificus, a Gram-negative food-borne pathogen. The amino acid sequence predicted that VvpS consists of two functional domains, an N-terminal protease catalytic domain (PCD) and a C-terminal carbohydrate binding domain (CBD). A null mutation of vvpS significantly enhanced viability during stationary phase, as measured by enumerating CFU and differentially staining viable cells. The vvpS mutant reduced the release of cytoplasmic β-galactosidase and high-molecular-weight extracellular chromosomal DNA into the culture supernatants, indicating that VvpS contributes to the autolysis of V. vulnificus during stationary phase. VvpS is secreted via a type II secretion system (T2SS), and it exerts its effects on autolysis through intracellular accumulation during stationary phase. Consistent with this, a disruption of the T2SS accelerated intracellular accumulation of VvpS and thereby the autolysis of V. vulnificus. VvpS also showed peptidoglycan-hydrolyzing activity, indicating that the autolysis of V. vulnificus is attributed to the self-digestion of the cell wall by VvpS. The functions of the VvpS domains were assessed by C-terminal deletion analysis and demonstrated that the PCD indeed possesses a proteolytic activity and that the CBD is required for hydrolyzing peptidoglycan effectively. Finally, the vvpS mutant exhibited reduced virulence in the infection of mice. In conclusion, VvpS is a serine protease with a modular structure and plays an essential role in the autolysis and pathogenesis of V. vulnificus.
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Quiñones-Ramírez EI, Bonifacio IN, Betancourt-Rule M, Ramirez-Vives F, Vázquez-Salinas C. Putative virulence factors identified in Vibrio vulnificus strains isolated from oysters and seawater in Mexico. INTERNATIONAL JOURNAL OF ENVIRONMENTAL HEALTH RESEARCH 2010; 20:395-405. [PMID: 21161801 DOI: 10.1080/09603123.2010.491856] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The presence of Vibrio vulnificus was analyzed in oyster and estuarine water samples from Mexico by PCR amplification of the vvhA gene and some putative virulence factors were tested. Samples were collected from 12 different sampling points over a one-year period; 31% samples were positive for V. vulnificus and all isolates were identified as biotype 1. All strains were cytotoxic and proteolytic, 98% showed adherence to epithelial cells, 91.4% were DNase-positive, 77.6% were mucinase-positive, 97.8% were lecithinase-positive and 79.8% were lipase positive. Regarding colony morphology, 51% strains were opaque, 20% were translucid, 28% were both opaque and translucid, and 80.8% showed a capsule. This is the first report on the isolation of V. vulnificus strains from environmental samples in Mexico, which may pose a health risk for local fisherman and seafood consumers.
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Gulig PA, Crécy-Lagard VD, Wright AC, Walts B, Telonis-Scott M, McIntyre LM. SOLiD sequencing of four Vibrio vulnificus genomes enables comparative genomic analysis and identification of candidate clade-specific virulence genes. BMC Genomics 2010; 11:512. [PMID: 20863407 PMCID: PMC3091676 DOI: 10.1186/1471-2164-11-512] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Accepted: 09/24/2010] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Vibrio vulnificus is the leading cause of reported death from consumption of seafood in the United States. Despite several decades of research on molecular pathogenesis, much remains to be learned about the mechanisms of virulence of this opportunistic bacterial pathogen. The two complete and annotated genomic DNA sequences of V. vulnificus belong to strains of clade 2, which is the predominant clade among clinical strains. Clade 2 strains generally possess higher virulence potential in animal models of disease compared with clade 1, which predominates among environmental strains. SOLiD sequencing of four V. vulnificus strains representing different clades (1 and 2) and biotypes (1 and 2) was used for comparative genomic analysis. RESULTS Greater than 4,100,000 bases were sequenced of each strain, yielding approximately 100-fold coverage for each of the four genomes. Although the read lengths of SOLiD genomic sequencing were only 35 nt, we were able to make significant conclusions about the unique and shared sequences among the genomes, including identification of single nucleotide polymorphisms. Comparative analysis of the newly sequenced genomes to the existing reference genomes enabled the identification of 3,459 core V. vulnificus genes shared among all six strains and 80 clade 2-specific genes. We identified 523,161 SNPs among the six genomes. CONCLUSIONS We were able to glean much information about the genomic content of each strain using next generation sequencing. Flp pili, GGDEF proteins, and genomic island XII were identified as possible virulence factors because of their presence in virulent sequenced strains. Genomic comparisons also point toward the involvement of sialic acid catabolism in pathogenesis.
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Affiliation(s)
- Paul A Gulig
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, USA
| | - Valérie de Crécy-Lagard
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Anita C Wright
- Department of Food Science and Human Nutrition, University of Florida, Gainesville, Florida, USA
| | - Brandon Walts
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, USA
| | - Marina Telonis-Scott
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, USA
- Department of Genetics, University of Melbourne, 3010 Australia
| | - Lauren M McIntyre
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, USA
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Saville RM, Dieckmann N, Spormann AM. Spatiotemporal activity of the mshA gene system in Shewanella oneidensis MR-1 biofilms. FEMS Microbiol Lett 2010; 308:76-83. [PMID: 20487019 DOI: 10.1111/j.1574-6968.2010.01995.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Type IV pili and a putative EPS biosynthetic gene cluster (mxdABCD) have been implicated previously in biofilm formation in Shewanella oneidensis MR-1. Here, we report that the mannose-sensitive hemagglutinin (MSHA) pilus mediates a reversible, d-mannose-sensitive association of cells to the substratum surface or to other cells that is critical within the first 5 microm of the biofilm from the substratum. The presence of the MSHA pilus alone is insufficient to confer biofilm-forming capacity; its activity, as mediated by the putative pilus retraction motor protein, PilT, is also required. Deletion of pilD, encoding the type IV pili prepilin peptidase, revealed that additional PilD substrate(s) may be involved in biofilm formation beyond the major structural pilin of the MSHA pilus. We also present data showing that the MSHA pilus and mxd genes encode for a complementary set of molecular machineries that constitute the dominant mechanisms enabling biofilm formation in this microorganism under hydrodynamic conditions.
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Affiliation(s)
- Renée M Saville
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, USA
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Functional characterization of the IlpA protein of Vibrio vulnificus as an adhesin and its role in bacterial pathogenesis. Infect Immun 2010; 78:2408-17. [PMID: 20308294 DOI: 10.1128/iai.01194-09] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Vibrio vulnificus is a Gram-negative bacterium that causes a fatal septicemia. One of its virulence factors is a membrane-bound lipoprotein, IlpA, which can induce cytokine production in human immune cells. In the present study, the role of IlpA as an adhesion molecule was investigated. An ilpA-deleted V. vulnificus mutant showed significantly decreased adherence to INT-407 human intestinal epithelial cells, which in turn resulted in reduced cytotoxicity. The DeltailpA mutant recovered the adherence ability of the wild type by complementation in trans with the intact ilpA gene. In addition, pretreatment of V. vulnificus with anti-IlpA polyclonal antibodies resulted in a significant reduction of bacterial adherence. To localize the domain of IlpA required for cytoadherence, three truncated recombinant IlpA polypeptides were constructed and tested for the ability to adhere to human cells by a ligand-binding immunoblot assay and fluorescence microscopy. The polypeptide containing the carboxy (C)-terminal hydrophilic domain exhibited direct binding to INT-407 cells. Therefore, the C-terminal domain of IlpA allows this protein to be an adhesion molecule of V. vulnificus.
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Identification of a c-di-GMP-regulated polysaccharide locus governing stress resistance and biofilm and rugose colony formation in Vibrio vulnificus. Infect Immun 2010; 78:1390-402. [PMID: 20065022 DOI: 10.1128/iai.01188-09] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
As an etiological agent of bacterial sepsis and wound infections, Vibrio vulnificus is unique among the Vibrionaceae. Its continued environmental persistence and transmission are bolstered by its ability to colonize shellfish, form biofilms on various marine biotic surfaces, and generate a morphologically and physiologically distinct rugose (R) variant that yields profuse biofilms. Here, we identify a c-di-GMP-regulated locus (brp, for biofilm and rugose polysaccharide) and two transcription factors (BrpR and BrpT) that regulate these physiological responses. Disruption of glycosyltransferases within the locus or either regulator abated the inducing effect of c-di-GMP on biofilm formation, rugosity, and stress resistance. The same lesions, or depletion of intracellular c-di-GMP levels, abrogated these phenotypes in the R variant. The parental and brp mutant strains formed only scant monolayers on glass surfaces and oyster shells, and although the R variant formed expansive biofilms, these were of limited depth. Dramatic vertical expansion of the biofilm structure was observed in the parental strain and R variant, but not the brp mutants, when intracellular c-di-GMP levels were elevated. Hence, the brp-encoded polysaccharide is important for surface colonization and stress resistance in V. vulnificus, and its expression may control how the bacteria switch from a planktonic lifestyle to colonizing shellfish to invading human tissue.
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Grimes DJ, Johnson CN, Dillon KS, Flowers AR, Noriea NF, Berutti T. What genomic sequence information has revealed about Vibrio ecology in the ocean--a review. MICROBIAL ECOLOGY 2009; 58:447-460. [PMID: 19727929 DOI: 10.1007/s00248-009-9578-9] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Accepted: 08/07/2009] [Indexed: 05/28/2023]
Abstract
To date, the genomes of eight Vibrio strains representing six species and three human pathogens have been fully sequenced and reported. This review compares genomic information revealed from these sequencing efforts and what we can infer about Vibrio biology and ecology from this and related genomic information. The focus of the review is on those attributes that allow the Vibrios to survive and even proliferate in their ocean habitats, which include seawater, plankton, invertebrates, fish, marine mammals, plants, man-made structures (surfaces), and particulate matter. Areas covered include general information about the eight genomes, each of which is distributed over two chromosomes; a discussion of expected and unusual genes found; attachment sites and mechanisms; utilization of particulate and dissolved organic matter; and conclusions.
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Affiliation(s)
- Darrell Jay Grimes
- Department of Coastal Sciences, Gulf Coast Research Laboratory, The University of Southern Mississippi, 703 East Beach Drive, Ocean Springs, MS 39564, USA.
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Chattopadhyay S, Paranjpye RN, Dykhuizen DE, Sokurenko EV, Strom MS. Comparative evolutionary analysis of the major structural subunit of Vibrio vulnificus type IV pili. Mol Biol Evol 2009; 26:2185-96. [PMID: 19556347 DOI: 10.1093/molbev/msp124] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Type IV pili contribute to virulence in Vibrio vulnificus, the bacterium responsible for the majority of fatal seafood-related infections. Here, we performed within- and between-species evolutionary analysis of the gene that encodes the major structural subunit of the pilus, pilA, by comparing it with pilD and gyrB, the genes encoding the type IV prepilin peptidase and beta subunit of DNA gyrase, respectively. Although the diversity in pilD and gyrB is similar to each other and likely to have accumulated after speciation of V. vulnificus, pilA is several times more diverse at both nonsynonymous and synonymous levels. Also, in contrast to pilD and gyrB, there are virtually unrestricted and highly localized horizontal movements of pilA alleles between the major phylogenetic groups of V. vulnificus. The frequent movement of pilA involves homologous recombination of the entire gene with no evidence for intragenic recombination between the alleles. We propose that pilA allelic diversity and horizontal movement is maintained in the population by both diversifying and frequency-dependent selection most likely to escape shellfish innate immunity defense or lytic phages. Other possibilities leading to such selection dynamics of V. vulnificus pilA could involve adaptation to diverse host populations or within-host compartments, or natural DNA uptake and transformation. We show that the history of nucleotide diversification in pilA predates V. vulnificus speciation and this diversification started at or before the time of the last common ancestor for V. vulnificus, Vibrio parahaemolyticus, and Vibrio cholerae. At the same time, it appears that within the various pilA groups of V. vulnificus, there is no positive selection for structural mutations and consequently no evidence for source-sink selection. In contrast, pilD has accumulated a number of apparently adaptive mutations in the regions encoding the membrane-spanning portions of the prepilin peptidase, possibly affecting fimbrial expression and/or function, and is being subjected to source-sink selection dynamics.
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Hasegawa H, Häse CC. The extracellular metalloprotease of Vibrio tubiashii directly inhibits its extracellular haemolysin. MICROBIOLOGY-SGM 2009; 155:2296-2305. [PMID: 19389767 DOI: 10.1099/mic.0.028605-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Vibrio tubiashii is a re-emerging pathogen of molluscs that secretes a variety of extracellular products (ECPs), including a metalloprotease and a cytolysin/haemolysin. Previously, we reported that the V. tubiashii haemolysin locus consists of two ORFs (vthB and vthA), similar to that of the homologous haemolysin genes (vvhB and vvhA) found in Vibrio vulnificus. Here, we demonstrate that the concomitant expression of both V. tubiashii genes resulted in significantly higher haemolytic activity than the vthA gene alone. In addition, we created a VthAB- mutant strain of V. tubiashii that was virtually devoid of haemolytic activity in liquid media. Interestingly, significant production of an additional haemolysin(s) was observed on blood plates. Moreover, we have previously reported that in V. tubiashii, proteolytic and haemolytic activities are inversely produced during bacterial growth. Here, we study this correlation in more detail and present evidence that the VtpA metalloprotease inhibits haemolytic activity in culture supernatants, based on the following evidence: (i) loss of metalloprotease activity by either mutation or EDTA inhibition resulted in increased haemolytic activity; (ii) overexpression of the vtpA gene resulted in decreased haemolytic activity; (iii) purified VtpA metalloprotease directly diminished haemolytic activity by purified VthA haemolysin. Importantly, we found not only that vthAB gene expression remained high throughout growth but also that there were no dramatic differences in vthAB gene expression between the parent and VtpA- mutant strains. Thus, our results strongly suggest that the V. tubiashii metalloprotease directly targets its haemolysin.
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Affiliation(s)
- Hiroaki Hasegawa
- Department of Biomedical Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - Claudia C Häse
- Department of Biomedical Sciences, Oregon State University, Corvallis, OR 97331, USA
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Localization and characterization of VVA0331, a 489-kDa RTX-like protein, in Vibrio vulnificus YJ016. Arch Microbiol 2009; 191:441-50. [PMID: 19326097 DOI: 10.1007/s00203-009-0471-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2008] [Revised: 02/19/2009] [Accepted: 03/06/2009] [Indexed: 12/19/2022]
Abstract
Vibrio vulnificus YJ016 contains three genes encoding proteins homologous to repeats-in-toxin proteins. One of these genes, vva0331, possesses a long open reading frame of 13,971 bp in length and resides on the small chromosome between two gene clusters encoding a type I secretion system and several regulatory proteins, respectively. Bioinformatic analysis revealed that VVA0331 consist of nineteen 87-amino acid repeats, two Arg-Gly-Asp motifs, four cysteine residues, an outer membrane protein domain, a polysaccharide-binding site and several motifs related to cell adhesions. These features are distinct from those of typical repeat-in-toxins and autotransporter adhesins. Real-time quantitative PCR analysis indicates that vva0331 gene expression is activated at 30 degrees C and regulated by iron. In addition, VVA0331 is present primarily in a secreted form as determined by cell fractionation assay and Western blot analysis. No significant difference in Hep2 cell adherence, cytotoxicity, and virulence was observed between the wild type and vva0331 mutant strains. In contrast, these strains exhibited apparently different outer membrane protein profiles, and antiserum raised against C-terminal region of VVA0331 reacted with an 85-kDa outer membrane protein of V. vulnificus YJ016.
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Vibrio biofilms: so much the same yet so different. Trends Microbiol 2009; 17:109-18. [PMID: 19231189 DOI: 10.1016/j.tim.2008.12.004] [Citation(s) in RCA: 314] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2008] [Revised: 11/11/2008] [Accepted: 12/05/2008] [Indexed: 12/20/2022]
Abstract
Vibrios are natural inhabitants of aquatic environments and form symbiotic or pathogenic relationships with eukaryotic hosts. Recent studies reveal that the ability of vibrios to form biofilms (i.e. matrix-enclosed, surface-associated communities) depends upon specific structural genes (flagella, pili and exopolysaccharide biosynthesis) and regulatory processes (two-component regulators, quorum sensing and c-di-GMP signaling). Here, we compare and contrast mechanisms and regulation of biofilm formation by Vibrio species, with a focus on Vibrio cholerae, Vibrio parahaemolyticus, Vibrio vulnificus and Vibrio fischeri. Although many aspects are the same, others differ dramatically. Crucial questions that remain to be answered regarding the molecular underpinnings of Vibrio biofilm formation are also discussed.
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Miyoshi SI, Sultan SZ, Yasuno Y, Shinoda S. GROWTH PHASE-DEPENDENT PRODUCTION OF A TOXIC METALLOPROTEASE BY VIBRIO VULNIFICUS. TOXIN REV 2008. [DOI: 10.1080/15569540500320862] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Park J, Ryu SY, Kim CM, Shin SH. Two forms of Vibrio vulnificus metalloprotease VvpE are secreted via the type II general secretion system. J Microbiol 2008; 46:338-43. [PMID: 18604505 DOI: 10.1007/s12275-008-0058-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2008] [Accepted: 04/22/2008] [Indexed: 12/19/2022]
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.
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Affiliation(s)
- Jong Park
- Research Center for Resistant Cells, Chosun University Medical School, Gwangju, Republic of Korea
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Global gene expression as a function of the iron status of the bacterial cell: influence of differentially expressed genes in the virulence of the human pathogen Vibrio vulnificus. Infect Immun 2008; 76:4019-37. [PMID: 18573903 DOI: 10.1128/iai.00208-08] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vibrio vulnificus multiplies rapidly in host tissues under iron-overloaded conditions. To understand the effects of iron in the physiology of this pathogen, we performed a genome-wide transcriptional analysis of V. vulnificus growing at three different iron concentrations, i.e., iron-limiting [Trypticase soy broth with 1.5% NaCl (TSBS) plus ethylenediamine-di-(o-hydroxyphenylacetic) acid (EDDA)], low-iron (1 microg Fe/ml; TSBS), and iron-rich (38 microg Fe/ml; TSBS plus ferric ammonium citrate) concentrations. A few genes were upregulated under the last two conditions, while several genes were expressed differentially under only one of them. A gene upregulated under both conditions encodes the outer membrane porin, OmpH, while others are related to the biosynthesis of amino sugars. An ompH mutant showed sensitivity to sodium dodecyl sulfate (SDS) and polymyxin B and also had a reduced competitive index compared with the wild type in the iron-overloaded mice. Under iron-limiting conditions, two of the TonB systems involved in vulnibactin transport were induced. These genes were essential for virulence in the iron-overloaded mice inoculated subcutaneously, underscoring the importance of active iron transport in infection, even under the high-iron conditions of this animal model. Furthermore, we demonstrated that a RyhB homologue is also essential for virulence in the iron-overloaded mouse. This novel information on the role of genes induced under iron limitation in the iron-overloaded mouse model and the finding of new genes with putative roles in virulence that are expressed only under iron-rich conditions shed light on the many strategies used by this pathogen to multiply rapidly in the susceptible host.
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Evidence that AphB, essential for the virulence of Vibrio vulnificus, is a global regulator. J Bacteriol 2008; 190:3768-73. [PMID: 18344367 DOI: 10.1128/jb.00058-08] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The Vibrio vulnificus aphB mutant was significantly less virulent than the wild type and was impaired in motility and adherence to host cells. Microarray analysis revealed that AphB of V. vulnificus (AphB(Vv)) influences the expression of over 10% of the V. vulnificus genome. The combined results indicated that AphB(Vv) is a global regulator contributing to the pathogenesis of V. vulnificus.
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Vibrio vulnificus rtxE is important for virulence, and its expression is induced by exposure to host cells. Infect Immun 2008; 76:1509-17. [PMID: 18250174 DOI: 10.1128/iai.01503-07] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Numerous secreted virulence factors have been proposed to account for the fulminating and destructive nature of Vibrio vulnificus infections. A mutant of V. vulnificus that exhibited less cytotoxicity to INT-407 human intestinal epithelial cells was screened from a library of mutants constructed by random transposon mutagenesis. A transposon-tagging method was used to identify and clone an open reading frame encoding an RTX toxin secretion ATP binding protein, RtxE, from V. vulnificus. The deduced amino acid sequence of RtxE from V. vulnificus was 91% identical to that reported from Vibrio cholerae. Functions of the rtxE gene in virulence were assessed by constructing an isogenic mutant whose rtxE gene was inactivated by allelic exchanges and by evaluating the differences between its virulence phenotype and that of the wild type in vitro and in mice. The disruption of rtxE blocked secretion of RtxA to the cell exterior and resulted in a significant reduction in cytotoxic activity against epithelial cells in vitro. Also, the intraperitoneal 50% lethal dose of the rtxE mutant was 10(4) to 10(5) times higher than that of the parental wild type, indicating that RtxE is essential for the virulence of V. vulnificus. Furthermore, the present study demonstrated that the rtxBDE genes are transcribed as one transcriptional unit under the control of a single promoter, P(rtxBDE). The activity of V. vulnificus P(rtxBDE) is induced by exposure to INT-407 cells, and the induction requires direct contact of the bacteria with the host cells.
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37
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Yanez ME, Korotkov KV, Abendroth J, Hol WGJ. The crystal structure of a binary complex of two pseudopilins: EpsI and EpsJ from the type 2 secretion system of Vibrio vulnificus. J Mol Biol 2008; 375:471-86. [PMID: 18022192 PMCID: PMC2219201 DOI: 10.1016/j.jmb.2007.10.035] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2007] [Revised: 10/10/2007] [Accepted: 10/12/2007] [Indexed: 11/20/2022]
Abstract
Type II secretion systems (T2SS) translocate virulence factors from the periplasmic space of many pathogenic bacteria into the extracellular environment. The T2SS of Vibrio cholerae and related species is called the extracellular protein secretion (Eps) system that consists of a core of multiple copies of 11 different proteins. The pseudopilins, EpsG, EpsH, EpsI, EpsJ and EpsK, are five T2SS proteins that are thought to assemble into a pseudopilus, which is assumed to interact with the outer membrane pore, and may actively participate in the export of proteins. We report here biochemical evidence that the minor pseudopilins EpsI and EpsJ from Vibrio species interact directly with one another. Moreover, the 2.3 A resolution crystal structure of a complex of EspI and EpsJ from Vibrio vulnificus represents the first atomic resolution structure of a complex of two different pseudopilin components from the T2SS. Both EpsI and EpsJ appear to be structural extremes within the family of type 4a pilin structures solved to date, with EpsI having the smallest, and EpsJ the largest, "variable pilin segment" seen thus far. A high degree of sequence conservation in the EpsI:EpsJ interface indicates that this heterodimer occurs in the T2SS of a large number of bacteria. The arrangement of EpsI and EpsJ in the heterodimer would correspond to a right-handed helical character of proteins assembled into a pseudopilus.
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Affiliation(s)
- Marissa E Yanez
- Department of Biochemistry, Biomolecular Structure Center, University of Washington, Box 357742, Seattle, WA 98195, USA
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38
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Paranjpye RN, Johnson AB, Baxter AE, Strom MS. Role of type IV pilins in persistence of Vibrio vulnificus in Crassostrea virginica oysters. Appl Environ Microbiol 2007; 73:5041-4. [PMID: 17557854 PMCID: PMC1951050 DOI: 10.1128/aem.00641-07] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2007] [Accepted: 06/01/2007] [Indexed: 11/20/2022] Open
Abstract
Vibrio vulnificus is part of the natural estuarine microflora and accumulates in shellfish through filter feeding. It is responsible for the majority of seafood-associated fatalities in the United States mainly through consumption of raw oysters. Previously we have shown that a V. vulnificus mutant unable to express PilD, the type IV prepilin peptidase, does not express pili on the surface of the bacterium and is defective in adherence to human epithelial cells (R. N. Paranjpye, J. C. Lara, J. C. Pepe, C. M. Pepe, and M. S. Strom, Infect. Immun. 66:5659-5668, 1998). A mutant unable to express one of the type IV pilins, PilA, is also defective in adherence to epithelial cells as well as biofilm formation on abiotic surfaces (R. N. Paranjpye and M. S. Strom, Infect. Immun. 73:1411-1422, 2005). In this study we report that the loss of PilD or PilA significantly reduces the ability of V. vulnificus to persist in Crassostrea virginica over a 66-h interval, strongly suggesting that pili expressed by this bacterium play a role in colonization or persistence in oysters.
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39
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Goo SY, Han YS, Kim WH, Lee KH, Park SJ. Vibrio vulnificus IlpA-induced cytokine production is mediated by Toll-like receptor 2. J Biol Chem 2007; 282:27647-58. [PMID: 17640874 DOI: 10.1074/jbc.m701876200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Vibrio vulnificus is a pathogenic bacterium causing primary septicemia, which follows a classical septic shock pathway, including an overwhelming inflammatory cytokine response. In this study, we identified a putative lipoprotein of V. vulnificus, encoded by the ilpA gene, as one of the surface proteins that specifically reacted with the antibodies raised against outer membrane proteins of V. vulnificus. Using a mutant V. vulnificus in which its ilpA gene was knocked out, we found that IlpA is important in the production of interferon-gamma in human peripheral blood mononuclear cells. Production of tumor necrosis factor-alpha and interleukin-6 is also induced by the recombinant IlpA (rIlpA) in human monocytes. Lipidation of the rIlpA was observed by in vivo labeling in Escherichia coli. Experiments using the mutant IlpA, which is unable to be modified by lipidation, indicate that the lipid moiety of this protein has an essential property for cytokine production in human cells. Pretreatment of monocytes with antibodies against Toll-like receptor 2 (TLR2) inhibited production of both tumor necrosis factor-alpha and interleukin-6. The role of TLR2 in IlpA-induced cytokine production was confirmed by an in vitro assay, in which only the TLR2-expressing cells showed a dramatic induction of nuclear factor-kappaB activity by rIlpA. In addition, rIlpA treatment resulted in induction of TLR2 transcription in human cells. In comparison with the wild type V. vulnificus, the ilpA mutant showed a reduced mortality in mice. These results demonstrate that IlpA of V. vulnificus functions as an immunostimulant to human cells via TLR2.
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Affiliation(s)
- Sung Young Goo
- Department of Environmental Medical Biology and Institute of Tropical Medicine, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea
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40
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Kim CM, Kang SM, Jeon HJ, Shin SH. Production of Vibrio vulnificus metalloprotease VvpE begins during the early growth phase: Usefulness of gelatin-zymography. J Microbiol Methods 2007; 70:96-102. [PMID: 17467832 DOI: 10.1016/j.mimet.2007.03.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2006] [Revised: 03/21/2007] [Accepted: 03/27/2007] [Indexed: 12/17/2022]
Abstract
Recent studies have demonstrated that expression of the vvpE gene begins during the early growth phase albeit at low levels. However, we found that the traditional protease assay method that is used to measure caseinolytic activity in culture supernatants is not suitable for the measurement of extracellular VvpE that is produced at low levels during the early growth phase. By using gelatin-zymography in place of the protease assay, we could specifically detect only VvpE of several proteases produced by Vibrio vulnificus. Moreover, we could sensitively measure VvpE produced at low levels during the early growth phase, which was consistent with transcription of the vvpE gene. The extracellular production of VvpE was reduced or delayed by mutation of the pilD gene which encodes for the type IV leader peptidase/N-methyltransferase associated with the type II general secretion system; the delayed production of VvpE was recovered by in trans complementation of the wild-type pilD gene. These results indicate that VvpE begins to be produced during the early growth phase via the PilD-mediated type II general secretion system, and that the use of gelatin-zymography is recommended as a simple method for the sensitive and specific detection of VvpE production.
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Affiliation(s)
- Choon-Mee Kim
- Research Center for Resistant Cells, Chosun University Medical School, 375 Seosuk-Dong, Dong-Gu, Gwangju 501-759, Republic of Korea
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41
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Duggan PS, Gottardello P, Adams DG. Molecular analysis of genes in Nostoc punctiforme involved in pilus biogenesis and plant infection. J Bacteriol 2007; 189:4547-51. [PMID: 17416648 PMCID: PMC1913353 DOI: 10.1128/jb.01927-06] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Hormogonia are the infective agents in many cyanobacterium-plant symbioses. Pilus-like appendages are expressed on the hormogonium surface, and mutations in pil-like genes altered surface piliation and reduced symbiotic competency. This is the first molecular evidence that pilus biogenesis in a filamentous cyanobacterium requires a type IV pilus system.
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Affiliation(s)
- Paula S Duggan
- Institute of Integrative and Comparative Biology, Garstang Building, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom
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42
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DebRoy S, Dao J, Söderberg M, Rossier O, Cianciotto NP. Legionella pneumophila type II secretome reveals unique exoproteins and a chitinase that promotes bacterial persistence in the lung. Proc Natl Acad Sci U S A 2006; 103:19146-51. [PMID: 17148602 PMCID: PMC1748190 DOI: 10.1073/pnas.0608279103] [Citation(s) in RCA: 168] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Type II protein secretion is critical for Legionella pneumophila infection of amoebae, macrophages, and mice. Previously, we found several enzymes to be secreted by this (Lsp) secretory pathway. To better define the L. pneumophila type II secretome, a 2D electrophoresis proteomic approach was used to compare proteins in wild-type and type II mutant supernatants. We identified 20 proteins that are type II-dependent, including aminopeptidases, an RNase, and chitinase, as well as proteins with no homology to known proteins. Because a chitinase had not been previously reported in Legionella, we determined that wild type secretes activity against both p-nitrophenyl triacetyl chitotriose and glycol chitin. An lsp mutant had a 70-75% reduction in activity, confirming the type II dependency of the secreted chitinase. Newly constructed chitinase (chiA) mutants also had approximately 75% less activity, and reintroduction of chiA restored the mutants to normal levels of activity. Although chiA mutants were not impaired for in vitro intracellular infection, they were defective upon intratracheal inoculation into the lungs of A/J mice, and antibodies against ChiA were detectable in infected animals. In contrast, mutants lacking a secreted phosphatase, protease, or one of several lipolytic enzymes were not defective in vivo. In sum, this study shows that the output of type II secretion is greater in magnitude than previously appreciated and includes previously undescribed proteins. Our data also indicate that an enzyme with chitinase activity can promote infection of a mammalian host.
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Affiliation(s)
- Sruti DebRoy
- Department of Microbiology–Immunology, Northwestern University Medical School, Chicago, IL 60611
| | - Jenny Dao
- Department of Microbiology–Immunology, Northwestern University Medical School, Chicago, IL 60611
| | - Maria Söderberg
- Department of Microbiology–Immunology, Northwestern University Medical School, Chicago, IL 60611
| | - Ombeline Rossier
- Department of Microbiology–Immunology, Northwestern University Medical School, Chicago, IL 60611
| | - Nicholas P. Cianciotto
- Department of Microbiology–Immunology, Northwestern University Medical School, Chicago, IL 60611
- *To whom correspondence should be addressed. E-mail:
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Goo SY, Lee HJ, Kim WH, Han KL, Park DK, Lee HJ, Kim SM, Kim KS, Lee KH, Park SJ. Identification of OmpU of Vibrio vulnificus as a fibronectin-binding protein and its role in bacterial pathogenesis. Infect Immun 2006; 74:5586-94. [PMID: 16988233 PMCID: PMC1594942 DOI: 10.1128/iai.00171-06] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vibrio vulnificus is a pathogenic bacterium that causes gastroenteritis and primary septicemia. To identify factors involved in microbial adherence to the host cells, we investigated bacterial proteins capable of binding to fibronectin, one of the main components comprised of the extracellular matrix of mammalian cells. A protein of approximately 35 kDa was purified from the extracts of V. vulnificus by its property to bind to immobilized fibronectin. This protein was identified as OmpU, one of the major outer membrane proteins of V. vulnificus. In binding assays using immobilized fibronectin, the number of ompU mutant cells bound to fibronectin was only 4% of that of wild-type cells bound to fibronectin. In addition, the exogenous addition of antibodies against OmpU resulted in a decreased ability of wild-type V. vulnificus to adhere to fibronectin. The ompU mutant was also defective in its adherence to RGD tripeptide (5% of the adherence of the wild type to RGD), cytoadherence to HEp-2 cells (7% of the adherence of the wild type to HEp-2), cytotoxicity to cell cultures (39% of the cytotoxicity of the wild type), and mortality in mice (10-fold increase in the 50% lethal dose). The ompU mutant complemented with the intact ompU gene restored its abilities for adherence to fibronectin, RGD tripeptide, and HEp-2 cells; cytotoxicity to HEp-2 cells; and mouse lethality. This study indicates that OmpU is an important virulence factor involved in the adherence of V. vulnificus to the host cells.
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Affiliation(s)
- Sung Young Goo
- Department of Parasitology, Yonsei University School of Medicine, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-752, Korea
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Starks AM, Bourdage KL, Thiaville PC, Gulig PA. Use of a marker plasmid to examine differential rates of growth and death between clinical and environmental strains of Vibrio vulnificus in experimentally infected mice. Mol Microbiol 2006; 61:310-23. [PMID: 16856938 DOI: 10.1111/j.1365-2958.2006.05227.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Vibrio vulnificus is Gram-negative bacterium that contaminates oysters, causing highly lethal sepsis after consumption of raw oysters and wound infection. We previously described two sets of V. vulnificus strains with different levels of virulence in subcutaneously inoculated iron dextran-treated mice. Both virulent, clinical strains and attenuated, environmental strains could be recovered in high numbers from skin lesions and livers; however, the attenuated environmental strains required significantly higher numbers of colony-forming units (cfu) in the inoculum to produce lethal infection. Using some of these strains and an additional clinical strain, we presently asked if the different abilities to cause infection between the clinical and environmental strains were due to differences in rates of growth or death of the bacteria in the mouse host. We therefore constructed a marker plasmid, pGTR902, that functions as a replicon only in the presence of arabinose, which is not present in significant levels in animal tissues. V. vulnificus strains containing pGTR902 were inoculated into iron dextran-treated and untreated mice. Measuring the proportion of bacteria that had maintained the marker plasmid recovered from mice enabled us to monitor the number of in vivo divisions, hence growth rate; whereas measuring the number of marker plasmid-containing bacteria recovered enabled the measurement of death of the vibrios in the mice. The numbers of bacterial divisions in vivo for all of the strains over a 12-15 h infection period were not significantly different in iron dextran-treated mice; however, the rate of death of one environmental strain was significantly higher compared with the clinical strains. Infection of non-iron dextran-treated mice with clinical strains demonstrated that the greatest effect of iron dextran-treatment was increased growth rate, while one clinical strain also experienced increased death in untreated mice. V. vulnificus inoculated into iron dextran-treated mice replicated extremely rapidly over the first 4 h of infection with doubling times of approximately 15-28 min. In contrast, one of the environmental strains exhibited a reduced early growth rate. These results demonstrate that differences in virulence among naturally occurring V. vulnificus can be explained by diverse abilities to replicate rapidly in or resist defences of the host. The marker plasmid pGTR902 should be useful for examining virulence of bacteria in terms of differentiating growth verses death in animal hosts for most Gram-negative bacteria.
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Affiliation(s)
- Angela M Starks
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida College of Medicine, Gainesville, FL, USA
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Rodkhum C, Hirono I, Stork M, Di Lorenzo M, Crosa JH, Aoki T. Putative virulence-related genes in Vibrio anguillarum identified by random genome sequencing. JOURNAL OF FISH DISEASES 2006; 29:157-66. [PMID: 16533301 DOI: 10.1111/j.1365-2761.2006.00692.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The genome of Vibrio anguillarum strain H775-3 was partially determined by a random sequencing procedure. A total of 2,300 clones, 2,100 from a plasmid library and 200 from a cosmid library, were sequenced and subjected to homology search by the BLAST algorithm. The total length of the sequenced clones is 1.5 Mbp. The nucleotide sequences were classified into 17 broad functional categories. Forty putative virulence-related genes were identified, 36 of which are novel in V. anguillarum, including a repeat in toxin gene cluster, haemolysin genes, enterobactin gene, protease genes, lipopolysaccharide biosynthesis genes, capsule biosynthesis gene, flagellar genes and pilus genes.
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Affiliation(s)
- C Rodkhum
- Laboratory of Genome Science, Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, Tokyo, Japan
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46
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Wong HC, Liu SH, Chen MY. Virulence and stress susceptibility of clinical and environmental strains of Vibrio vulnificus isolated from samples from Taiwan and the United States. J Food Prot 2005; 68:2533-40. [PMID: 16355823 DOI: 10.4315/0362-028x-68.12.2533] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Vibrio vulnificus is an estuarine bacterium that causes severe wound infection and septicemia with high mortality. It also can be transmitted through the consumption of raw contaminated seafood and is an important foodborne pathogen. A total of 40 environmental and clinical V. vulnificus strains isolated from the United States and Taiwan were analyzed for virulence in animals, the presence of virulence-associated factors, and susceptibility to environmental stresses. Virulence in mice was exhibited by 85% of the environmental strains and 95% of the clinical strains. Strains from environmental or clinical sources were similar in virulence-associated phenotypes (protease activity, utilization of transferrin-bound iron, hemolysis, and inactivation in serum) and susceptibility to various stresses (4 and 52 degrees C, 0.1 and 10% NaCl, and pH 3.2), except freeze-thaw treatment. The clinical strains killed experimental animals after a shorter incubation time than did the environmental strains. Most of the 15 virulence-associated genes examined were present in most of the strains, regardless of their sources or virulence, with the exception of vvh, flgF, and purH. vvh was significantly more common in clinical strains than in environmental strains, and vvh, flgF, and purH were more common in virulent strains than in nonvirulent strains. These data may be helpful in devising strategies to manage or reduce the presence of V. vulnificus in foods.
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Affiliation(s)
- Hin-Chung Wong
- Department of Microbiology, Soochow University, Taipei, Taiwan 111, Republic of China.
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Shin SH, Sun HY, Park RY, Kim CM, Kim SY, Rhee JH. Vibrio vulnificusmetalloprotease VvpE has no direct effect on the iron-assimilation from human holotransferrin. FEMS Microbiol Lett 2005; 247:221-9. [PMID: 15936899 DOI: 10.1016/j.femsle.2005.05.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2004] [Revised: 04/04/2005] [Accepted: 05/05/2005] [Indexed: 12/17/2022] Open
Abstract
In order to elucidate the role of Vibrio vulnificus metalloprotease VvpE in the uptake of iron from human transferrin, we constructed a VvpE-deficient mutant and a merozygotic vvpE-transcriptional reporter from the wild type strain MO6-24/O. All three strains were able to grow only in deferrated Heart Infusion broth (DF-HI) with human holotransferrin (HT), but not in DF-HI containing partially iron-saturated transferrin or apotransferrin, without noticeable differences among the strains. All strains consumed most iron in the early growth phase. Both the transcription and extracellular production of VvpE proceeded at undetectable levels when bacterial growth was severely retarded in the DF-HI. When HT or FeCl(3) was added to the DF-HI, the retarded bacterial growth was restored and vvpE transcription dramatically increased in the late growth phase, but the extracellular VvpE production was negligible as compared to its transcription. All strains were unable to degrade HT even in normal HI broth containing HT, in which extracellular VvpE activity was remarkably high. The uptake of iron from HT in all strains was consistent with the production of catechol-siderophore rather than hydroxamate-siderophore. Similar results were also observed when clinical isolates from septicemic patients were used. In conclusion, we determined that VvpE was not directly involved in the siderophore-mediated iron-uptake from human transferrin. In addition, the discrepancy between the transcription and extracellular production of VvpE suggests that additional posttranscriptional events are involved in the extracellular production of VvpE.
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Affiliation(s)
- Sung-Heui Shin
- Research Center for Resistant Cells and Department of Microbiology, Chosun University Medical School, 375 Seosuk-Dong, Dong-Gu, Gwangju 501-759, Republic of Korea.
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Wong TW, Wang YY, Sheu HM, Chuang YC. Bactericidal effects of toluidine blue-mediated photodynamic action on Vibrio vulnificus. Antimicrob Agents Chemother 2005; 49:895-902. [PMID: 15728881 PMCID: PMC549273 DOI: 10.1128/aac.49.3.895-902.2005] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Vibrio vulnificus is a gram-negative, highly invasive bacterium responsible for human opportunistic infections. We studied the antibacterial effects of toluidine blue O (TBO)-mediated photodynamic therapy (PDT) for V. vulnificus wound infections in mice. Fifty-three percent (10 of 19) of mice treated with 100 microg of TBO per ml and exposed to broad-spectrum red light (150 J/cm(2) at 80 mW/cm(2)) survived, even though systemic septicemia had been established with a bacterial inoculum 100 times the 50% lethal dose. In vitro, the bacteria were killed after exposure to a lower light dose (100 J/cm(2) at 80 mW/cm(2)) in the presence of low-dose TBO (0.1 microg/ml). PDT severely damaged the cell wall and reduced cell motility and virulence. Cell-killing effects were dependent on the TBO concentration and light doses and were mediated partly through the reactive oxygen species generated during the photodynamic reaction. Our study has demonstrated that PDT can cure mice with otherwise fatal V. vulnificus wound infections. These promising results suggest the potential of this regimen as a possible alternative to antibiotics in future clinical applications.
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Affiliation(s)
- Tak-Wah Wong
- Department of Dermatology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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49
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Paranjpye RN, Strom MS. A Vibrio vulnificus type IV pilin contributes to biofilm formation, adherence to epithelial cells, and virulence. Infect Immun 2005; 73:1411-22. [PMID: 15731039 PMCID: PMC1064924 DOI: 10.1128/iai.73.3.1411-1422.2005] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vibrio vulnificus expresses a multitude of cell-associated and secreted factors that potentially contribute to pathogenicity, although the specific roles of most of these factors have been difficult to define. Previously we have shown that a mutation in pilD (originally designated vvpD), which encodes a type IV prepilin peptidase/N-methyltransferase, abolishes expression of surface pili, suggesting that they belong to the type IV class. In addition, a pilD mutant exhibits reduced adherence to HEp-2 cells, a block in secretion of several exoenzymes that follow the type II secretion pathway, and decreased virulence. In this study, we have cloned and characterized a V. vulnificus type IV pilin (PilA) that shares extensive homology to group A type IV pilins expressed by many pathogens, including Vibrio cholerae (PilA), Pseudomonas aeruginosa (PilA), and Aeromonas hydrophila (TapA). The V. vulnificus pilA gene is part of an operon and is clustered with three other pilus biogenesis genes, pilBCD. Inactivation of pilA reduces the ability of V. vulnificus to form biofilms and significantly decreases adherence to HEp-2 cells and virulence in iron dextran-treated mice. Southern blot analysis demonstrates the widespread presence of both pilA and pilD in clinical as well as environmental strains of V. vulnificus.
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Affiliation(s)
- Rohinee N Paranjpye
- Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric, Seattle, WA 98112, USA
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50
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Ruby EG, Urbanowski M, Campbell J, Dunn A, Faini M, Gunsalus R, Lostroh P, Lupp C, McCann J, Millikan D, Schaefer A, Stabb E, Stevens A, Visick K, Whistler C, Greenberg EP. Complete genome sequence of Vibrio fischeri: a symbiotic bacterium with pathogenic congeners. Proc Natl Acad Sci U S A 2005; 102:3004-9. [PMID: 15703294 PMCID: PMC549501 DOI: 10.1073/pnas.0409900102] [Citation(s) in RCA: 252] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Vibrio fischeri belongs to the Vibrionaceae, a large family of marine gamma-proteobacteria that includes several dozen species known to engage in a diversity of beneficial or pathogenic interactions with animal tissue. Among the small number of pathogenic Vibrio species that cause human diseases are Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus, the only members of the Vibrionaceae that have had their genome sequences reported. Nonpathogenic members of the genus Vibrio, including a number of beneficial symbionts, make up the majority of the Vibrionaceae, but none of these species has been similarly examined. Here we report the genome sequence of V. fischeri ES114, which enters into a mutualistic symbiosis in the light organ of the bobtail squid, Euprymna scolopes. Analysis of this sequence has revealed surprising parallels with V. cholerae and other pathogens.
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Affiliation(s)
- E G Ruby
- Pacific Biomedical Research Center, Kewalo Marine Laboratory, and W. M. Keck Microbial Communities and Cell Signaling Program, University of Hawaii, Honolulu, HI 96813, USA.
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