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Sensitive and rapid detection of cholera toxin-producing Vibrio cholerae using loop-mediated isothermal amplification. Methods Mol Biol 2011; 739:13-22. [PMID: 21567314 DOI: 10.1007/978-1-61779-102-4_2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Loop-mediated isothermal amplification (LAMP) is an established nucleic acid amplification method offering rapid, accurate, and cost-effective diagnosis of infectious diseases. The LAMP assay requires 12-18 min for amplification with a single colony on selective agar from cholera toxin (CT)-producing Vibrio cholerae strains and less than 60 min with human feces and seafood samples. The assay requires less than 35 and 80 min for the detection of CT-producing V. cholerae with a colony on selective agar and with human feces and seafood samples from the beginning of DNA extraction to final determination. The LAMP amplification can be judged by both turbidimetric analysis and visual assessment with the unaided eye. The sensitivity of the LAMP assay is tenfold higher than that of the PCR assay. The LAMP assay is a powerful tool for rapid, simple, and sensitive detection of CT-producing V. cholerae which may facilitate the investigation of V. cholerae contamination in seafood, as well as the early diagnosis of cholera in humans.
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2
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Toxin mediated diarrhea in the 21 century: the pathophysiology of intestinal ion transport in the course of ETEC, V. cholerae and rotavirus infection. Toxins (Basel) 2010; 2:2132-57. [PMID: 22069677 PMCID: PMC3153279 DOI: 10.3390/toxins2082132] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Accepted: 08/09/2010] [Indexed: 12/31/2022] Open
Abstract
An estimated 4 billion episodes of diarrhea occur each year. As a result, 2–3 million children and 0.5–1 million adults succumb to the consequences of this major healthcare concern. The majority of these deaths can be attributed to toxin mediated diarrhea by infectious agents, such as E. coli, V. cholerae or Rotavirus. Our understanding of the pathophysiological processes underlying these infectious diseases has notably improved over the last years. This review will focus on the cellular mechanism of action of the most common enterotoxins and the latest specific therapeutic approaches that have been developed to contain their lethal effects.
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De Haan L, Hirst TR. Cholera toxin: A paradigm for multi-functional engagement of cellular mechanisms (Review). Mol Membr Biol 2009; 21:77-92. [PMID: 15204437 DOI: 10.1080/09687680410001663267] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Cholera toxin (Ctx) from Vibrio cholerae and its closely related homologue, heat-labile enterotoxin (Etx) from Escherichia coli have become superb tools for illuminating pathways of cellular trafficking and immune cell function. These bacterial protein toxins should be viewed as conglomerates of highly evolved, multi-functional elements equipped to engage the trafficking and signalling machineries of cells. Ctx and Etx are members of a larger family of A-B toxins of bacterial (and plant) origin that are comprised of structurally and functionally distinct enzymatically active A and receptor-binding B sub-units or domains. Intoxication of mammalian cells by Ctx and Etx involves B pentamer-mediated receptor binding and entry into a vesicular pathway, followed by translocation of the enzymatic A1 domain of the A sub-unit into the target cell cytosol, where covalent modification of intracellular targets leads to activation of adenylate cyclase and a sequence of events culminating in life-threatening diarrhoeal disease. Importantly, Ctx and Etx also have the capacity to induce a wide spectrum of remarkable immunological processes. With respect to the latter, it has been found that these toxins activate signalling pathways that modulate the immune system. This review explores the complexities of the cellular interactions that are engaged by these bacterial protein toxins, and highlights some of the new insights to have recently emerged.
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Affiliation(s)
- Lolke De Haan
- Department of Pathology and Microbiology, School of Medical Sciences, University of Bristol, United Kingdom
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4
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Yamazaki W, Seto K, Taguchi M, Ishibashi M, Inoue K. Sensitive and rapid detection of cholera toxin-producing Vibrio cholerae using a loop-mediated isothermal amplification. BMC Microbiol 2008; 8:94. [PMID: 18547441 PMCID: PMC2446398 DOI: 10.1186/1471-2180-8-94] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2008] [Accepted: 06/12/2008] [Indexed: 11/12/2022] Open
Abstract
Background Vibrio cholerae is widely acknowledged as one of the most important waterborne pathogen causing gastrointestinal disorders. Cholera toxin (CT) is a major virulence determinant of V. cholerae. Detection of CT-producing V. cholerae using conventional culture-, biochemical- and immunological-based assays is time-consuming and laborious, requiring more than three days. Thus, we developed a novel and highly specific loop-mediated isothermal amplification (LAMP) assay for the sensitive and rapid detection of cholera toxin (CT)-producing Vibrio cholerae. Results The assay provided markedly more sensitive and rapid detection of CT-producing V. cholerae strains than conventional biochemical and PCR assays. The assay correctly identified 34 CT-producing V. cholerae strains, but did not detect 13 CT non-producing V. cholerae and 53 non-V. cholerae strains. Sensitivity of the LAMP assay for direct detection of CT-producing V. cholerae in spiked human feces was 7.8 × 102 CFU per g (1.4 CFU per reaction). The sensitivity of the LAMP assay was 10-fold more sensitive than that of the conventional PCR assay. The LAMP assay for detection of CT-producing V. cholerae required less than 35 min with a single colony on thiosulfate citrate bile salt sucrose (TCBS) agar and 70 min with human feces from the beginning of DNA extraction to final determination. Conclusion The LAMP assay is a sensitive, rapid and simple tool for the detection of CT-producing V. cholerae and will be useful in facilitating the early diagnosis of human V. cholerae infection.
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Affiliation(s)
- Wataru Yamazaki
- Division of Bacteriology, Osaka Prefectural Institute of Public Health, Osaka, Japan.
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Bagley KC, Shata MT, Onyabe DY, DeVico AL, Fouts TR, Lewis GK, Hone DM. Immunogenicity of DNA vaccines that direct the coincident expression of the 120 kDa glycoprotein of human immunodeficiency virus and the catalytic domain of cholera toxin. Vaccine 2003; 21:3335-41. [PMID: 12804865 DOI: 10.1016/s0264-410x(03)00038-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Passive antibody studies unequivocally demonstrate that sterilizing immunity against lentiviruses is obtainable through humoral mechanisms. In this regard, DNA vaccines represent an inexpensive alternative to subunit vaccine for mass vaccination programs designed to induce such responses to human immunodeficiency virus type I (HIV-1). At present, however, this vaccine modality has proven relatively ineffective at inducing humoral responses. In this report, we describe the immunogenicity of DNA vaccines that direct the coincident expression of the cholera toxin catalytic domain (CTA1) with that of the human immunodeficiency virus type I gp120 through genes either encoded in individual plasmids or in a single dicistronic plasmid. In BALB/cJ mice, coincident expression of CTA1 in either a separate plasmid or in the dicistronic plasmid in the DNA vaccines induced serum IgG responses to gp120 that were at least 1000-fold greater, and remained elevated longer than, the analogous responses in mice vaccinated with a DNA vaccine that expressed gp120 alone. In addition, mice vaccinated with CTA1 and gp120 produced significantly more gp120-specific IFN-gamma ELISPOTs than mice vaccinated with the gp120 DNA vaccine. Combined, these data show that the adjuvant properties of cholera toxin can be harnessed in DNA vaccine modalities.
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Affiliation(s)
- K C Bagley
- Division of Vaccine Research and Basic Science, Institute of Human Virology, University of Maryland Biotechnology Institute, 725 W. Lombard Street, Baltimore, MD, 212001, USA
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Karasawa T, Ito H, Tsukamoto T, Yamasaki S, Kurazono H, Faruque SM, Nair GB, Nishibuchi M, Takeda Y. Cloning and characterization of genes encoding homologues of the B subunit of cholera toxin and the Escherichia coli heat-labile enterotoxin from clinical isolates of Citrobacter freundii and E. coli. Infect Immun 2002; 70:7153-5. [PMID: 12438400 PMCID: PMC133046 DOI: 10.1128/iai.70.12.7153-7155.2002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We identified and characterized a gene encoding a homologue of the B subunits of cholera toxin (CTB) and heat-labile enterotoxin (LTB) of Escherichia coli from a clinical isolate of Citrobacter freundii that was found to produce a factor in the culture supernatant that cross-reacted with antibodies to CTB and LTB when assayed by enzyme-linked immunosorbent assay (ELISA). The gene encoding the ELISA-positive factor, cfxB, consisted of 375 nucleotides and was located downstream of an 852-nucleotide open reading frame, cfxA, with a 56-nucleotide intergenic space. The cfxB gene was predicted to encode a 125-amino-acid polypeptide, which had 73.8 and 72.8% identities with the amino acid sequences of LTB and CTB, respectively. However, the amino acid sequence of the deduced polypeptide CFXA had no homologies to those of the A subunits of CT or LT. DNA probes developed from the sequences of cfxA and cfxB were used to screen 67 C. freundii isolates and 152 E. coli isolates from diarrheal patients by colony blot hybridization. Two strains, C. freundii 48 and E. coli 176, reacted with both DNA probes under conditions of high stringency. We cloned homologues of the cfxA and cfxB genes from E. coli 176 and designated them ecxA and ecxB, respectively. The ecxA gene and the ecxB gene comprise 855 and 375 nucleotides, respectively, with a 50-nucleotide intergenic space, and encode a 285- and a 125-amino-acid residue polypeptides, respectively. The results of the present study may provide important clues to the origin and evolution of immunologically related factors sharing a common enterotoxin-like A and B subunit structures.
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Affiliation(s)
- Tadahiro Karasawa
- Department of Bacteriology, Graduate School of Medical Science, Kanazawa University, 13-1 Takara-machi, Japan.
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7
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van Baar BL, Hulst AG, Wils ER. Characterisation of cholera toxin by liquid chromatography--electrospray mass spectrometry. Toxicon 1999; 37:85-108. [PMID: 9920483 DOI: 10.1016/s0041-0101(98)00136-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Cholera toxin, one of the toxins that may be generated by various strains of the bacterium Vibrio cholerae, can be considered as a substance possibly used in biological warfare. The possibilities of characterising the toxin by liquid chromatography electrospray mass spectrometry (LC-ES-MS) were investigated. The toxin can be detected by flow-injection (FIA) ES-MS of a dialysed solution and observation of the charge envelope signals of its A-unit and B-chain protein; sufficient information for identification by the molecular mass of either protein could be obtained for quantities in the order of 10 fmol. Confirmatory analysis was carried out by 2-mercaptoethanol reduction and FIA-ES-MS detection of the product proteins or by tryptic digest LC-ES-MS with ion chromatogram detection of most of the tryptic fragments of the A-unit and B-chain from the singly, doubly or triply charged ion signals. The confirmatory tryptic digest LC-ES-MS analysis could be achieved with quantities as low as 1 pmol. Possible biovariations in the toxin can mostly be determined by sequencing, where the amino acid composition of tryptic fragments of the A1-chain, T5 and T15, and of the B-chain, T1, T4 and T5, cover all known biovariations. Partial sequencing of cholera toxin, originating from a classical strain, O1/569B, was achieved by LC-ES-MS/MS of most tryptic fragments larger than three amino acid residues.
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Affiliation(s)
- B L van Baar
- TNO Prins Maurits Laboratory, Rijswijk, The Netherlands
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Slauch J, Taylor R, Maloy S. Survival in a cruel world: how Vibrio cholerae and Salmonella respond to an unwilling host. Genes Dev 1997; 11:1761-74. [PMID: 9242485 DOI: 10.1101/gad.11.14.1761] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- J Slauch
- Department of Microbiology, University of Illinois, Urbana 61801, USA
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Fando R, Pérez JL, Rodriguez BL, Campos J, Robert A, García L, Silva A, Benitez JA. Promoter activities in Vibrio cholerae ctx phi prophage. Infect Immun 1997; 65:1561-5. [PMID: 9119505 PMCID: PMC175171 DOI: 10.1128/iai.65.4.1561-1565.1997] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Comparison of cholera toxin (CT) production directed by different gene constructs and S1 nuclease mapping revealed the presence of a ctxB-specific promoter within the ctxA coding sequence. Initiation of transcription in this region occurred in wild-type El Tor and classical biotype choleragenic vibrios. We propose that transcription from the ctxB-specific promoter and a stronger ribosomal binding site on the ctxB mRNA synergistically contribute to achieve the correct (5B:1A) subunit stoichiometry. Plasmid pB, a CT promoterless vector expressing only CTB, was used to detect promoter activity by restoration of A-subunit synthesis. Promoter activity expressed in vitro and in vivo was detected upstream of the zonula occludens toxin gene, suggesting that this factor could be produced in vivo to contribute to fluid accumulation. No promoter activity was detected in vitro and in vivo upstream from the accessory cholera enterotoxin gene.
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Affiliation(s)
- R Fando
- Centro Nacional de Investigaciones Científicas, Havana, Cuba
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Yamamoto K, Do Valle GR, Xu M, Miwatani T, Honda T. Amino acids of the cholera toxin from Vibrio cholerae O37 strain S7 which differ from those of strain O1. Gene 1995; 163:155-6. [PMID: 7557467 DOI: 10.1016/0378-1119(95)00415-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- K Yamamoto
- Department of Bacterial Infections, Osaka University, Japan
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11
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Abstract
Despite more than a century of study, cholera still presents challenges and surprises to us. Throughout most of the 20th century, cholera was caused by Vibrio cholerae of the O1 serogroup and the disease was largely confined to Asia and Africa. However, the last decade of the 20th century has witnessed two major developments in the history of this disease. In 1991, a massive outbreak of cholera started in South America, the one continent previously untouched by cholera in this century. In 1992, an apparently new pandemic caused by a previously unknown serogroup of V. cholerae (O139) began in India and Bangladesh. The O139 epidemic has been occurring in populations assumed to be largely immune to V. cholerae O1 and has rapidly spread to many countries including the United States. In this review, we discuss all aspects of cholera, including the clinical microbiology, epidemiology, pathogenesis, and clinical features of the disease. Special attention will be paid to the extraordinary advances that have been made in recent years in unravelling the molecular pathogenesis of this infection and in the development of new generations of vaccines to prevent it.
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Affiliation(s)
- J B Kaper
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore 21201
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12
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Wright AC, Guo Y, Johnson JA, Nataro JP, Morris JG. Development and testing of a nonradioactive DNA oligonucleotide probe that is specific for Vibrio cholerae cholera toxin. J Clin Microbiol 1992; 30:2302-6. [PMID: 1400994 PMCID: PMC265496 DOI: 10.1128/jcm.30.9.2302-2306.1992] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
An alkaline phosphatase-labeled oligonucleotide DNA probe (CTAP) that was specific for the cholera toxin gene (ctxA) was identified. All cholera toxin-producing strains of Vibrio cholerae, regardless of serotype, hybridized with the CTAP probe, while nontoxigenic strains from either environmental sources or from deletion or substitution mutations did not hybridize. Unlike the whole-gene probes for either ctxA or for the heat-labile toxin or Escherichia coli (eltA), this 23-base sequence did not hybridize with E. coli or with vibrios other than V. cholerae that produce related toxins. By using CTAP to identify colonies grown on nonselective medium, V. cholerae was enumerated at concentrations of 10(3) to 10(7)/g from stool samples of volunteers who had ingested V. cholerae O1 strain 569B. CTAP provides a specific and sensitive tool for diagnosis and environmental monitoring of cholera toxin-producing V. cholerae.
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Affiliation(s)
- A C Wright
- Department of Medicine, University of Maryland School of Medicine, Baltimore 21201
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13
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Moyenuddin M, Wachsmuth K, Richardson SH, Cook WL. Enteropathogenicity of non-toxigenic Vibrio cholerae O1 for adult mice. Microb Pathog 1992; 12:451-8. [PMID: 1522800 DOI: 10.1016/0882-4010(92)90008-c] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The enteropathogenic potential of 32 Vibrio cholerae O1 isolates that do not produce cholera toxin was examined in the orally inoculated, sealed adult mouse model. Live cultures (2 x 10(10) cfu/ml) of 7/16 clinical and 6/16 environmental isolates produced a positive intestinal fluid accumulation (FA) ratio that reached near maximum at approximately 5 h post-inoculation. Colony hybridization did not detect genes for cholera toxin, Escherichia coli heat-labile and heat-stable toxins, or shiga-like toxins. FA activity did not correlate precisely with cytotoxic activities on Chinese hamster ovary (28/32 positive), Vero (29/32) or HeLa (25/32) cells. Certain clinical and environmental isolates of non-toxigenic V. cholerae O1 appear to be enteropathogenic for the mouse, providing evidence that they may have pathogenic potential for humans through an as yet undefined mechanism(s).
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Affiliation(s)
- M Moyenuddin
- Laboratory of Biological Sciences, Georgia State University, Atlanta 30303
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14
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Connell TD, Holmes RK. Characterization of hybrid toxins produced in Escherichia coli by assembly of A and B polypeptides from type I and type II heat-labile enterotoxins. Infect Immun 1992; 60:1653-61. [PMID: 1548088 PMCID: PMC257043 DOI: 10.1128/iai.60.4.1653-1661.1992] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The genes encoding the individual A and B polypeptides of the type I enterotoxin LTp-I and type II enterotoxins LT-IIa and LT-IIb were cloned and tested for complementation in Escherichia coli. Each gene encoding an A polypeptide was cloned into pACYC184, and each gene encoding a B polypeptide was cloned into the compatible plasmid Bluescript KS+. In addition, operon fusions representing all combinations of A and B genes were constructed in Bluescript KS+. Extracts from strains of E. coli expressing each combination of A and B genes, either from compatible plasmids or from operon fusions, were tested for immunoreactive holotoxin by radioimmunoassays and for toxicity by Y1 adrenal cell assays. Biologically active holotoxin was detected in each case, but the toxicity of extracts containing the hybrid toxins was usually less than that of extracts containing the wild-type holotoxins. The ganglioside-binding activity of each holotoxin was tested, and in each case, the B polypeptide determined the ganglioside-binding specificity. The A and B polypeptides of the type II heat-labile enterotoxins were also shown to form holotoxin in vitro without exposure to denaturing conditions, in contrast to the polypeptides of the type I enterotoxins that failed to form holotoxin in vitro under comparable conditions. These findings suggest that type I and type II enterotoxins have conserved structural features that permit their A and B polypeptides to form hybrid holotoxins, although the B polypeptides of the type I and type II enterotoxins have very little amino acid sequence homology.
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Affiliation(s)
- T D Connell
- Department of Microbiology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814
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15
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Galen JE, Ketley JM, Fasano A, Richardson SH, Wasserman SS, Kaper JB. Role of Vibrio cholerae neuraminidase in the function of cholera toxin. Infect Immun 1992; 60:406-15. [PMID: 1730470 PMCID: PMC257643 DOI: 10.1128/iai.60.2.406-415.1992] [Citation(s) in RCA: 132] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Vibrio cholerae neuraminidase (NANase) is hypothesized to act synergistically with cholera toxin (CT) and increase the severity of a secretory response by increasing the binding and penetration of CT to enterocytes. To test this hypothesis, the NANase gene (nanH) from V. cholerae Ogawa 395 was first cloned and sequenced. Isogenic wild-type and NANase- V. cholerae 395 strains were then constructed by using suicide vector-mediated mutagenesis. The influence of NANase on CT binding and penetration was examined in vitro by using culture filtrates from these isogenic strains. Fluorescence due to binding of fluorescein-conjugated CT to C57BL/6 and C3H mouse fibroblasts exposed to NANase+ filtrates increased five- and eightfold, respectively, relative to that with NANase- filtrates. In addition, NANase+ filtrates increased the short-circuit current measured in Ussing chambers 65% relative to that with NANase- filtrates, although this difference decreased as production of CT increased. The role of NANase in V. cholerae pathogenesis was examined in vivo by intragastric inoculation of the isogenic strains into CD1 suckling mice. No difference in fluid accumulation ratios was seen at doses of 10(4) to 10(8) CFU, but NANase+ strains produced 18% higher fluid accumulation ratios at 10(9) CFU than NANase- strains when inoculated into nonfasted suckling mice. It is concluded that NANase plays a subtle but significant role in the binding and uptake of CT by susceptible cells under defined conditions.
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Affiliation(s)
- J E Galen
- Department of Medicine, University of Maryland School of Medicine, Baltimore 21201
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16
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Tamatsukuri S, Yamamoto K, Shibata S, Leaño F, Honda T, Miwatani T. Detection of a heat-labile enterotoxin gene in enterotoxigenic Escherichia coli by densitometric evaluation using highly specific enzyme-linked oligonucleotide probes. Eur J Clin Microbiol Infect Dis 1991; 10:1048-55. [PMID: 1802695 DOI: 10.1007/bf01984927] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Two alkaline phosphatase-conjugated 24-mer oligonucleotide probes were developed to detect the heat-labile enterotoxin gene in enterotoxigenic Escherichia coli. Probes were antisense codon sequences, which are transcribed into mRNA, of the heat-labile enterotoxin gene of enterotoxigenic Escherichia coli of human origin. Using dot-blot hybridization, probes were tested with 100 clinical isolates and evaluated by a reflectance-type densitometer. Results agreed very well with those of an immunological test, the Biken test, and a 32P-labelled recombinant DNA probe. The oligonucleotide probes did not react with nucleic acids prepared from other diarrhoeagenic bacterial pathogens. Thus, the alkaline phosphatase-conjugated oligonucleotide probes seem to be highly sensitive and specific for detection of heat-labile enterotoxin-producing enterotoxigenic Escherichia coli. Moreover, the results indicate a potential usefulness for densitometric evaluation of DNA hybridization.
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Affiliation(s)
- S Tamatsukuri
- Department of Bacteriology and Serology, Research Institute for Microbial Diseases, Osaka University, Japan
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17
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Dams E, De Wolf M, Dierick W. Nucleotide sequence analysis of the CT operon of the Vibrio cholerae classical strain 569B. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1090:139-41. [PMID: 1883840 DOI: 10.1016/0167-4781(91)90050-v] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The complete nucleotide sequence of the Vibrio cholerae classical strain 569B was determined. The results prove the exactness of the amino acid CT B sequence published by Takao et al. (1985, Eur. J. Biochem. 146, 503-508). A comparison is made with already reported CT genes.
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Affiliation(s)
- E Dams
- RUCA-Laboratory for Human Biochemistry, University of Antwerp, Belgium
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18
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Laboratory investigations on the low pathogenic potential of Plesiomonas shigelloides. J Clin Microbiol 1991; 29:148-53. [PMID: 1993749 PMCID: PMC269719 DOI: 10.1128/jcm.29.1.148-153.1991] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The pathogenic properties of 16 Plesiomonas shigelloides strains recovered from humans with extraintestinal and intestinal illnesses, infected animals, and environmental sources were investigated. Most strains possessed a high cell charge and low surface hydrophobicity analogous to those of Shigella spp.; additionally, serogroup O:17 strains reacted with Shigella group D antisera. However, unlike the shigellae, P. shigelloides strains did not universally bind Congo red, were noninvasive in HEp-2 cell assays, and did not produce a Shiga-like toxin on Vero cells. On HEp-2, Y1, and possibly Vero cells, a low-level cytolysin was consistently produced by all 16 P. shigelloides strains when grown in either Evan Casamino Acids-yeast extract or Penassay broth. The median 50% lethal dose for all 16 P. shigelloides strains in outbred Swiss Webster mice was 3.5 x 10(8) CFU (range, 3.2 x 10(7) to greater than 1 x 10(9) CFU). Animal pathogenicity did not correlate with cytolysin expression, possession of a greater than or equal to 120-MDa plasmid, protein profile, or resistance to complement-mediated lysis. No strain analyzed produced siderophores or a heat-stable enterotoxin. The results suggest that members of the genus Plesiomonas have an overall low pathogenic potential, irrespective of the site of isolation or phenotypic, serologic, or surface properties shared with other traditional enteropathogens.
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Abstract
Although great strides have been made in the development of recombinant attenuated Vibrio cholerae vaccine strains, the task has not been as simple as once imagined. The initial vaccine candidates proved to be unexpectedly reactogenic but further derivatives, such as CVD103-HgR, are well-tolerated, immunogenic and protective after a single dose. In addition, this strain carries a selectable marker to distinguish it from wild strains and has been evaluated in a practical, lyophilized formulation (Levine et al., 1988b). While CVD103-HgR is being further evaluated in expanded trials, we are also investigating a new secretogenic factor which could possibly explain the diarrhoea seen with the earlier vaccine strains. Hopefully, these studies will achieve the long-sought goal of a safe and effective vaccine for the prevention of cholera.
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Affiliation(s)
- J B Kaper
- Department of Medicine, University of Maryland School of Medicine, Baltimore 21201
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Honda S, Shimoirisa K, Adachi A, Saito K, Asano N, Taniguchi T, Honda T, Miwatani T. Clinical isolates of Vibrio cholerae O1 not producing cholera toxin. Lancet 1988; 2:1486. [PMID: 2904592 DOI: 10.1016/s0140-6736(88)90955-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Okamoto K, Okamoto K, Miyama A, Tsuji T, Honda T, Miwatani T. Effect of substitution of glycine for arginine at position 146 of the A1 subunit on biological activity of Escherichia coli heat-labile enterotoxin. J Bacteriol 1988; 170:2208-11. [PMID: 3129402 PMCID: PMC211108 DOI: 10.1128/jb.170.5.2208-2211.1988] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The ADP-ribosyltransferase activity of polypeptide A1 of cholera toxin and that of Escherichia coli heat-labile enterotoxin (LT) are primarily responsible for the toxic activities of these toxins. Since the amino acid sequences of the two A1 polypeptides are very similar, their functional mechanisms are considered to be the same. Arg-146 of polypeptide A1 is thought to be involved in the active site, because this amino acid of cholera toxin has been identified as the site of self-ADP-ribosylation. However, the exact role of Arg-146 and the significance of self-ADP-ribosylation in toxicity remain unclear. We substituted Arg-146 of polypeptide A1 of LT with Gly by oligonucleotide-directed mutagenesis and examined the biological property of the resultant mutant LT. The substitution changed the mobility of subunit A on sodium dodecyl sulfate-polyacrylamide gel but did not reduce the vascular permeability activity of LT. This result indicates that Arg-146 is not absolutely required for toxic activity and that LT can express its toxic activity without self-ADP-ribosylation at Arg-146.
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Affiliation(s)
- K Okamoto
- Department of Microbiology, School of Medicine, Fujita-Gakuen Health University, Aichi-ken, Japan
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Yamamoto T, Gojobori T, Yokota T. Evolutionary origin of pathogenic determinants in enterotoxigenic Escherichia coli and Vibrio cholerae O1. J Bacteriol 1987; 169:1352-7. [PMID: 3546273 PMCID: PMC211946 DOI: 10.1128/jb.169.3.1352-1357.1987] [Citation(s) in RCA: 93] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Three families of the evolutionarily related pathogenic determinants in enterotoxigenic Escherichia coli and Vibrio cholerae O1, a family of cholera enterotoxin (CT) and heat-labile enterotoxin (LT) including CT, LTh, and LTp, a family of heat-stable enterotoxin I (STI) including STIa and STIb, and a family of K88 enteroadhesion fimbriae including K88ab, K88ac, and K88ad were analyzed for synonymous (silent) nucleotide substitutions by using the gene nucleotide sequences of earlier reports and the LTp gene nucleotide sequence presented in this paper. The data suggested that the divergences between LT and CT and between STIa and STIb occurred in the remote past, whereas those between LTh and LTp and between members of the K88 family occurred very recently. We concluded that the LT gene is a foreign gene that has been acquired by E. coli to form an enteropathogen. This provides evolutionary evidence of species-to-species transfer of pathogenic determinants in procaryotes.
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