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Wei Q, Hu Q, Shi F, Li S, Sun C, Zhang H, Xue L, Feng Q, Dong J, Jiao Y, Zhou L. Rapid and quantitative detection of Shiga toxin1 and Shiga toxin2 based on multiple targets UPT-LF assay. Eng Life Sci 2020; 20:494-503. [PMID: 33204236 PMCID: PMC7645647 DOI: 10.1002/elsc.202000031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/29/2020] [Accepted: 07/08/2020] [Indexed: 11/24/2022] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) infection causes a series of diseases that are highly pathogenic and deadly in humans and animals, seriously endangering public health. Of the pathogenic factors within STEC, the two groups of Shiga toxin (Stx) consisting Stx1 and Stx2 plays a prominent role in the pathogenesis of STEC infection. In this study, we developed single-target up-converting phosphor technology-based lateral flow assay (Stx-UPT-LFA) for the rapid detection of Stx1 and Stx2, respectively, and also developed a dual-target Stx1/2-UPT-LFA based on single-target strips to detect of Stx1 and Stx2 at the meantime within 20 min. We choose the purified Stx1 and Stx2 standard samples, and the optimum monoclonal antibody (namely 8E7-E6, 2F6-F8 for Stx1 and S1D8, S2C4 for Stx2) were selected for use in Stx-UPT-LFA in double-antibody-sandwich mode. The sensitivities of single-target Stx-UPT-LFA for both Stx1 and Stx2 were 1 ng mL-1 with accurate quantitation ranges of 1-1000 ng mL-1 and 1-800 ng mL-1 respectively. No false-negative result was found in the Stx2-UPT-LFA even with a high-test concentration up to 1000 ng mL-1. Meanwhile, both targets detection sensitivities for dual-target Stx1/2-UPT-LFA were 5 ng mL-1, and accurate quantitation ranges were 5-1000 ng mL-1 and 5-800 ng mL-1 for standard Stx1 and Stx2 solutions without cross-interference between two targets. Both techniques showed good linearities, with a linear fitting coefficient of determination(r) of 0.9058-0.9918. Therefore, the UPT-LFA could realize simultaneous detection for multiple targets on a single strip and thus to quickly determine the type of infectious Stxs. In addition, the single-target Stx1-UPT-LFA and Stx2-UPT-LFA showed excellent specificity to six toxins, even at high concentrations of 1000 ng mL-1. In conclusion, the developed Stx-UPT-LFA allows the rapid, quantitative, reliable and simultaneous detection of Stx1 and Stx2 within 20 min, providing an alternative method for clinical diagnosis of STEC infection.
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Affiliation(s)
- Qiaozhen Wei
- National Key Laboratory of Biochemical EngineeringPLA Key Laboratory of Biopharmaceutical Production & Formulation EngineeringInstitute of Process EngineeringChinese Academy of SciencesBeijingP. R. China
- The Department of Blood TransfusionThe Second Affiliated Hospital of Anhui Medical UniversityHefeiP. R. China
| | - Qiushi Hu
- National Key Laboratory of Biochemical EngineeringPLA Key Laboratory of Biopharmaceutical Production & Formulation EngineeringInstitute of Process EngineeringChinese Academy of SciencesBeijingP. R. China
| | - Fengjuan Shi
- Institute of Pathogenic MicrobiologyJiangsu Provincial Center for Disease Prevention and ControlNanjingP. R. China
| | - Shuang Li
- National Key Laboratory of Biochemical EngineeringPLA Key Laboratory of Biopharmaceutical Production & Formulation EngineeringInstitute of Process EngineeringChinese Academy of SciencesBeijingP. R. China
| | - Chongsi Sun
- National Key Laboratory of Biochemical EngineeringPLA Key Laboratory of Biopharmaceutical Production & Formulation EngineeringInstitute of Process EngineeringChinese Academy of SciencesBeijingP. R. China
| | - Huicong Zhang
- National Key Laboratory of Biochemical EngineeringPLA Key Laboratory of Biopharmaceutical Production & Formulation EngineeringInstitute of Process EngineeringChinese Academy of SciencesBeijingP. R. China
| | - Lei Xue
- National Key Laboratory of Biochemical EngineeringPLA Key Laboratory of Biopharmaceutical Production & Formulation EngineeringInstitute of Process EngineeringChinese Academy of SciencesBeijingP. R. China
| | - QiuXia Feng
- National Key Laboratory of Biochemical EngineeringPLA Key Laboratory of Biopharmaceutical Production & Formulation EngineeringInstitute of Process EngineeringChinese Academy of SciencesBeijingP. R. China
| | - Jinying Dong
- National Key Laboratory of Biochemical EngineeringPLA Key Laboratory of Biopharmaceutical Production & Formulation EngineeringInstitute of Process EngineeringChinese Academy of SciencesBeijingP. R. China
| | - Yongjun Jiao
- Institute of Pathogenic MicrobiologyJiangsu Provincial Center for Disease Prevention and ControlNanjingP. R. China
| | - Lei Zhou
- National Key Laboratory of Biochemical EngineeringPLA Key Laboratory of Biopharmaceutical Production & Formulation EngineeringInstitute of Process EngineeringChinese Academy of SciencesBeijingP. R. China
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Wen T, Huang C, Zhang Y, Zeng X, Liu W, Jiao Z, Guo X, Jiao Y. Ultrasensitive detection of Shiga toxin 2 and its variants in Shiga toxin-producingEscherichia colistrains by a time-resolved fluorescence immunoassay. LUMINESCENCE 2018; 33:574-581. [DOI: 10.1002/bio.3448] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 11/21/2017] [Accepted: 11/29/2017] [Indexed: 11/06/2022]
Affiliation(s)
- Tian Wen
- Jiangsu Provincial Center for Disease Prevention and Control, Key Laboratory of Enteric Pathogenic Microbiology, Ministry Health; Institute of Pathogenic Microbiology; Nanjing Jiangsu Province P. R. China
| | - Chao Huang
- Jiangsu Provincial Center for Disease Prevention and Control, Key Laboratory of Enteric Pathogenic Microbiology, Ministry Health; Institute of Pathogenic Microbiology; Nanjing Jiangsu Province P. R. China
| | - Yi Zhang
- Jiangsu Key Laboratory of Molecular Nuclear Medicine; Jiangsu Institute of Nuclear Medicine; Wuxi Jiangsu Province P. R. China
| | - Xiaoyan Zeng
- Jiangsu Provincial Center for Disease Prevention and Control, Key Laboratory of Enteric Pathogenic Microbiology, Ministry Health; Institute of Pathogenic Microbiology; Nanjing Jiangsu Province P. R. China
| | - Wendong Liu
- Jiangsu Provincial Center for Disease Prevention and Control, Key Laboratory of Enteric Pathogenic Microbiology, Ministry Health; Institute of Pathogenic Microbiology; Nanjing Jiangsu Province P. R. China
| | - Zhenbang Jiao
- Mathematics School; Jilin University; Changchun Jilin Province P. R. China
| | - Xiling Guo
- Jiangsu Provincial Center for Disease Prevention and Control, Key Laboratory of Enteric Pathogenic Microbiology, Ministry Health; Institute of Pathogenic Microbiology; Nanjing Jiangsu Province P. R. China
| | - Yongjun Jiao
- Jiangsu Provincial Center for Disease Prevention and Control, Key Laboratory of Enteric Pathogenic Microbiology, Ministry Health; Institute of Pathogenic Microbiology; Nanjing Jiangsu Province P. R. China
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3
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Jiao Y, Legge FS, Zeng X, Treutlein HR, Zeng J. Antibody recognition of Shiga toxins (Stxs): computational identification of the epitopes of Stx2 subunit A to the antibodies 11E10 and S2C4. PLoS One 2014; 9:e88191. [PMID: 24516609 PMCID: PMC3917601 DOI: 10.1371/journal.pone.0088191] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 01/04/2014] [Indexed: 11/18/2022] Open
Abstract
We have recently developed a new method to predict the epitopes of the antigens that are
recognized by a specific antibody. In this work, we applied the method to identify the epitopes of
the Shiga toxin (Stx2 subunit A) that were bound by two specific antibodies 11E10 and S2C4. The
predicted epitopes of Stx2 binding to the antibody 11E10 resembles the recognition surface
constructed by the regions of Stx2 identified experimentally. For the S2C4, our results indicate
that the antibody recognizes the Stx2 at two different regions on the protein surface. The first
region (residues 246-254: ARSVRAVNE) is similar to the recognition region of the 11E10, while the
second region is formed by two epitopes. The second region is particularly significant because it
includes the amino acid sequence region that is diverse between Stx2 and other Stx (residues
176-188: QREFRQALSETAPV). This new recognition region is believed to play an important role in the
experimentally observed selectivity of S2C4 to the Stx2.
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Affiliation(s)
- Yongjun Jiao
- Institute of Pathogenic Microbiology, Jiangsu Provincial
Center for Disease Prevention and Control, Key Laboratory of Enteric Pathogenic Microbiology,
Ministry Health, Nanjing, China
| | - Fiona S. Legge
- Computist Bio-Nanotech, Small Technology Clusters,
Scoresby, Victoria, Australia
| | - Xiaoyan Zeng
- Institute of Pathogenic Microbiology, Jiangsu Provincial
Center for Disease Prevention and Control, Key Laboratory of Enteric Pathogenic Microbiology,
Ministry Health, Nanjing, China
| | - Herbert R. Treutlein
- Monash Institute of Pharmaceutical Sciences, Monash
University, Parkville, Victoria, Australia
- Computist Bio-Nanotech, Small Technology Clusters,
Scoresby, Victoria, Australia
- * E-mail: (HRT); (JZ)
| | - Jun Zeng
- Monash Institute of Pharmaceutical Sciences, Monash
University, Parkville, Victoria, Australia
- Computist Bio-Nanotech, Small Technology Clusters,
Scoresby, Victoria, Australia
- * E-mail: (HRT); (JZ)
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4
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Goldwater PN. Treatment and prevention of enterohemorrhagicEscherichia coliinfection and hemolytic uremic syndrome. Expert Rev Anti Infect Ther 2014; 5:653-63. [PMID: 17678428 DOI: 10.1586/14787210.5.4.653] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Over a quarter century after the discovery of verocytotoxin and the first report by Karmali and colleagues of cases of postdiarrheal hemolytic uremic syndrome (HUS) caused by verotoxigenic Escherichia coli (VTEC), otherwise known as Shiga-toxigenic E. coli (STEC), successful treatment of these infections has remained elusive. This is because the pathological insult producing the clinical picture of HUS occurs early in the disease process and curtails quickly, making treatment intervention a largely vain hope. Nevertheless, understanding of the pathogenesis of HUS has expanded and, as a result, we can expect a future breakthrough in the treatment of this life-threatening condition. This review examines the pathogenesis of HUS and explores targets for treatment, including the reasons why certain therapies have failed and why future therapies could be successful. This review also examines the status of vaccine development in prevention of VTEC/STEC disease.
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Affiliation(s)
- Paul N Goldwater
- The Women's & Children's Hospital, North Adelaide, South Australia, Australia.
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Gao X, Cai K, Li T, Wang Q, Hou X, Tian R, Liu H, Tu W, Xiao L, Fang L, Luo S, Liu Y, Wang H. Novel fusion protein protects against adherence and toxicity of enterohemorrhagic Escherichia coli O157:H7 in mice. Vaccine 2011; 29:6656-63. [PMID: 21742003 DOI: 10.1016/j.vaccine.2011.06.106] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Revised: 06/07/2011] [Accepted: 06/25/2011] [Indexed: 12/22/2022]
Abstract
Infection with Escherichia coli (E. coli) O157:H7 may develop into bloody diarrhea, or hemorrhagic uremic syndrome (HUS), which usually causes kidney failure or even death. Considered as the pathogenesis mechanism of E. coli O157:H7 infection, attachment or adhesion that is directly mediated by intimin is the first step of E. coli O157:H7 interaction with its host, and all these serious sequelae are mainly due to Shiga toxins (Stxs) released by E. coli O157:H7. In this study, a novel SSI fusion protein that contains the critical toxin-antigens Stx2B and Stx1B, and the critical adhesion-antigen fragment Int281 was constructed. The protein induced complete immune protection, with both anti-toxin and anti-adhesion effects. The dominant increase in IgG1 and the high level of Th2-typical cytokine (IL-4 and IL-10) expression showed that SSI significantly induced Th2-mediated humoral immune response. In the mouse model, the SSI fusion protein not only elicited neutralizing antibodies against both Stx1 and Stx2 toxins, but also induced a high level of anti-adhesion antibodies. The SSI-immunized mice did not show any pathologic changes. SSI provides evident protection with two-time immunization against a highly lethal dose of E. coli O157:H7.
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Affiliation(s)
- Xiang Gao
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Microbiology and Epidemiology, No. 20 Dongdajie, Fengtai District, Beijing 100071, PR China
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6
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Cai K, Gao X, Li T, Wang Q, Hou X, Tu W, Xiao L, Tian M, Liu Y, Wang H. Enhanced immunogenicity of a novel Stx2Am-Stx1B fusion protein in a mice model of enterohemorrhagic Escherichia coli O157:H7 infection. Vaccine 2011; 29:946-52. [DOI: 10.1016/j.vaccine.2010.11.035] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Revised: 10/22/2010] [Accepted: 11/14/2010] [Indexed: 10/18/2022]
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7
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Yamasaki S, Takeda Y. EnterohemorrhagicEscherichia coliO157:H7 Episode in Japan with a Perspective on Vero Toxins (Shiga-like Toxins). ACTA ACUST UNITED AC 2008. [DOI: 10.3109/15569549709016458] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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8
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Wen SX, Teel LD, Judge NA, O’Brien AD. A plant-based oral vaccine to protect against systemic intoxication by Shiga toxin type 2. Proc Natl Acad Sci U S A 2006; 103:7082-7. [PMID: 16641102 PMCID: PMC1459021 DOI: 10.1073/pnas.0510843103] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2005] [Indexed: 12/21/2022] Open
Abstract
Hemolytic uremic syndrome, the leading cause of kidney failure in children, often follows infection with enterohemorrhagic Escherichia coli and is mediated by the Shiga type toxins, particularly type 2 (Stx2), produced by such strains. The challenge in protecting against this life-threatening syndrome is to stimulate an immune response at the site of infection while also protecting against Shiga intoxication at distal sites such as the kidney. As one approach to meeting this challenge, we sought to develop and characterize a prototypic orally delivered, plant-based vaccine against Stx2, an AB5 toxin. First, we genetically inactivated the Stx2 active A subunit gene and then optimized both subunit genes for expression in plants. The toxoid genes were then transformed into the Nicotiana tabacum (tobacco) cell line NT-1 by Agrobacterium tumefaciens-mediated transformation. Toxoid expression was detected in NT-1 cell extracts, and the assembly of the holotoxoid was confirmed. Finally, mice were immunized by feeding with the toxoid-expressing NT-1 cells or by parenteral immunization followed by oral vaccination (prime-boost strategy). The immunized mice produced Stx2-specific mucosal IgA and Stx2-neutralizing serum IgG. The protective efficacy of these responses was assessed by challenging the immunized mice with E. coli O91:H21 strain B2F1, an isolate that produces an activatable variant of Stx2 (Stx2d) and is lethal to mice. The oral immunization fully protected mice from the challenge. Results of this study demonstrated that a plant-based oral vaccine can confer protection against lethal systemic intoxication.
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Affiliation(s)
- Sharon X. Wen
- *Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799; and
| | - Louise D. Teel
- *Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799; and
| | - Nicole A. Judge
- Department of Biology, Augusta State University, 2500 Walton Way, Augusta, GA 30904-2200
| | - Alison D. O’Brien
- *Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799; and
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9
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Tzipori S, Sheoran A, Akiyoshi D, Donohue-Rolfe A, Trachtman H. Antibody therapy in the management of shiga toxin-induced hemolytic uremic syndrome. Clin Microbiol Rev 2004; 17:926-41, table of contents. [PMID: 15489355 PMCID: PMC523565 DOI: 10.1128/cmr.17.4.926-941.2004] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Hemolytic uremic syndrome (HUS) is a disease that can lead to acute renal failure and often to other serious sequelae, including death. The majority of cases are attributed to infections with Escherichia coli, serotype O157:H7 strains in particular, which cause bloody diarrhea and liberate one or two toxins known as Shiga toxins 1 and 2. These toxins are thought to directly be responsible for the manifestations of HUS. Currently, supportive nonspecific treatment is the only available option for the management of individuals presenting with HUS. The benefit of antimicrobial therapy remains uncertain because of several reports which claim that such intervention can in fact exacerbate the syndrome. There have been only a few specific therapies directed against neutralizing the activities of these toxins, but none so far has been shown to be effective. This article reviews the literature on the mechanism of action of these toxins and the clinical manifestations and current management and treatment of HUS. The major focus of the article, however, is the development and rationale for using neutralizing human antibodies to combat this toxin-induced disease. Several groups are currently pursuing this approach with either humanized, chimeric, or human antitoxin antibodies produced in transgenic mice. They are at different phases of development, ranging from preclinical evaluation to human clinical trials. The information available from preclinical studies indicates that neutralizing specific antibodies directed against the A subunit of the toxin can be highly protective. Such antibodies, even when administered well after exposure to bacterial infection and onset of diarrhea, can prevent the occurrence of systemic complications.
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Affiliation(s)
- Saul Tzipori
- Division of Infectious Diseases, Tufts University School of Veterinary Medicine, 200 Westborough Rd., North Grafton, MA 01536, USA.
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10
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Affiliation(s)
- H Chart
- Laboratory of Enteric Pathogens, Central Public Health Laboratory, London, UK
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11
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6.10 Bacterial Exotoxins. J Microbiol Methods 1998. [DOI: 10.1016/s0580-9517(08)70291-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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12
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Sidjabat-Tambunan H, Bensink JC. Verotoxin-producing Escherichia coli from the faeces of sheep, calves and pigs. Aust Vet J 1997; 75:292-3. [PMID: 9140657 DOI: 10.1111/j.1751-0813.1997.tb10100.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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13
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Cao C, Yamasaki S, Lin Z, Kurazono H, Takeda Y. Specific detection of a verotoxin 2 variant, VT2vp1, by a bead-enzyme-linked immunosorbent assay. Microbiol Immunol 1994; 38:435-40. [PMID: 7968673 DOI: 10.1111/j.1348-0421.1994.tb01804.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A bead-enzyme-linked immunosorbent assay to specifically detect a Verotoxin 2 variant, VT2vp1, was developed. The sensitivity of the bead-ELISA was 200 pg/ml of the purified VT2vp1 and it did not react with 20 ng/ml of the purified VT2. The specificity of the bead-ELISA was examined with 107 strains of Verocytotoxin-producing Escherichia coli that include VT1-, VT2-, VT2vha-, VT2vhb- and VT2vp1-producing E. coli, and only VT2vp1-producing E. coli that were confirmed by VT2vp1-specific polymerase chain reaction gave positive results. It was noted that all 58 VT2vp1-producing E. coli strains were from pigs, but not from cows and humans.
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Affiliation(s)
- C Cao
- Department of Microbiology, Faculty of Medicine, Kyoto University, Japan
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14
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Takeda Y, Kurazono H, Yamasaki S. Vero toxins (Shiga-like toxins) produced by enterohemorrhagic Escherichia coli (verocytotoxin-producing E. coli). Microbiol Immunol 1993; 37:591-9. [PMID: 8246822 DOI: 10.1111/j.1348-0421.1993.tb01681.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Y Takeda
- Department of Microbiology, Faculty of Medicine, Kyoto University, Japan
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16
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Yamasaki S, Furutani M, Ito K, Igarashi K, Nishibuchi M, Takeda Y. Importance of arginine at position 170 of the A subunit of Vero toxin 1 produced by enterohemorrhagic Escherichia coli for toxin activity. Microb Pathog 1991; 11:1-9. [PMID: 1795624 DOI: 10.1016/0882-4010(91)90088-r] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Comparison of the primary structures of the A subunits of Vero toxin 1 (VT1), Vero toxin 2 (VT2), and two variants of VT2 (VT2vp and VT2vh) and the ricin A chain revealed three conserved regions (amino acid residues 51-55, 167-171 and 202-207 from the N-terminus of VT1). All three regions of the ricin A chain corresponded in position to the active site of ricin proposed by X-ray crystal diffraction analysis. To determine the relative importance of the conserved amino acid residues for toxin activity of VT1, we prepared VT1 mutants with single amino-acid substitutions by oligonucleotide-directed site-specific mutagenesis. A total of 22 mutants were prepared to examine 14 conserved residues, and their cytotoxicities to Vero cells and inhibitory activities on protein synthesis in a rabbit reticulocyte lysate were compared with those of wild-type VT1. Replacement of glutamic acid at position 167 by glutamine and of arginine at position 170 by leucine reduced both activities drastically. These results suggest that, in addition to the glutamic acid at position 167 reported previously, arginine at position 170 also plays an important role in the toxin activity of VT1. A possible chemical mechanism of the enzymatic (N-glycosidase) activity of VT1 is proposed based on the relative activities of various mutants.
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Affiliation(s)
- S Yamasaki
- Department of Microbiology, Faculty of Medicine, Kyoto University, Japan
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