51
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Zhang J, Kowal P, Fang J, Andreana P, Wang PG. Efficient chemoenzymatic synthesis of globotriose and its derivatives with a recombinant alpha-(1-->4)-galactosyltransferase. Carbohydr Res 2002; 337:969-76. [PMID: 12039536 DOI: 10.1016/s0008-6215(02)00106-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A truncated alpha-(1-->4)-galactosyltransferase (LgtC) gene from Neisseria meningitidis was cloned. The recombinant glycosyltransferase was expressed in Escherichia coli BL21 (DE3) strain with high specific activity (5 units/mg protein). Its acceptor specificity was carefully characterized. Then the purified enzyme was utilized in highly efficient syntheses of globotriose and a variety of alpha-(1-->4)-galactosylated derivatives as potential antibacterial agents.
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Affiliation(s)
- Jianbo Zhang
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA
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52
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Abstract
Escherichia coli is the best-known member of the normal microbiota of the human intestine and a versatile gastrointestinal pathogen. The varieties of E. coli that cause diarrhea are classified into named pathotypes, including enterotoxigenic, enteroinvasive, enteropathogenic and enterohemorrhagic E. coli. Individual strains of each pathotype possess a distinct set of virulence-associated characteristics that determine the clinical, pathological and epidemiological features of the diseases they cause. In the present brief review, we summarize the key distinguishing features of the major pathotypes of diarrheagenic E. coli. Knowledge of the pathogenic mechanisms of these bacteria has led to the development of rational interventions for the treatment and prevention of E. coli-induced diarrhea. In addition, investigations into E. coli virulence are providing useful insights into the origins and evolution of bacterial pathogens more generally.
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Affiliation(s)
- Roy M Robins-Browne
- Department of Microbiology and Immunology, University of Melbourne, Victoria 3010, Australia.
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53
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Schroeder CM, Zhao C, DebRoy C, Torcolini J, Zhao S, White DG, Wagner DD, McDermott PF, Walker RD, Meng J. Antimicrobial resistance of Escherichia coli O157 isolated from humans, cattle, swine, and food. Appl Environ Microbiol 2002; 68:576-81. [PMID: 11823193 PMCID: PMC126736 DOI: 10.1128/aem.68.2.576-581.2002] [Citation(s) in RCA: 177] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A total of 361 Escherichia coli O157 isolates, recovered from humans, cattle, swine, and food during the years 1985 to 2000, were examined to better understand the prevalence of antimicrobial resistance among these organisms. Based on broth microdilution results, 220 (61%) of the isolates were susceptible to all 13 antimicrobials tested. Ninety-nine (27%) of the isolates, however, were resistant to tetracycline, 93 (26%) were resistant to sulfamethoxazole, 61 (17%) were resistant to cephalothin, and 48 (13%) were resistant to ampicillin. Highest frequencies of resistance occurred among swine isolates (n = 70), where 52 (74%) were resistant to sulfamethoxazole, 50 (71%) were resistant to tetracycline, 38 (54%) were resistant to cephalothin, and 17 (24%) were resistant to ampicillin. Based on the presence of Shiga toxin genes as determined by PCR, 210 (58%) of the isolates were identified as Shiga toxin-producing E. coli (STEC). Among these, resistance was generally low, yet 21 (10%) were resistant to sulfamethoxazole and 19 (9%) were resistant to tetracycline. Based on latex agglutination, 189 (52%) of the isolates were identified as E. coli O157:H7, among which 19 (10%) were resistant to sulfamethoxazole and 16 (8%) were resistant to tetracycline. The data suggest that selection pressure imposed by the use of tetracycline derivatives, sulfa drugs, cephalosporins, and penicillins, whether therapeutically in human and veterinary medicine or as prophylaxis in the animal production environment, is a key driving force in the selection of antimicrobial resistance in STEC and non-STEC O157.
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Affiliation(s)
- Carl M Schroeder
- Department of Nutrition and Food Science, 3304 Marie Mount Hall, University of Maryland, College Park, MD 20742, USA
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54
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Kim SH, Yang SJ, Koo HC, Bae WK, Kim JY, Park JH, Baek YJ, Park YH. Inhibitory activity of Bifidobacterium longum HY8001 against Vero cytotoxin of Escherichia coli O157:H7. J Food Prot 2001; 64:1667-73. [PMID: 11726142 DOI: 10.4315/0362-028x-64.11.1667] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Vero cytotoxin (VT)-producing Escherichia coli (VTEC), such as E. coli O157:H7, are emerging foodborne pathogens worldwide. VTs are associated with hemorrhagic colitis and hemolytic uremic syndrome in humans. Attachment of the B subunit of VTs to its receptor, globotriaosylceramide (Gb3), at gut epithelium is the primary step and, consequently, the A subunit of VTs inhibits protein synthesis in the target cell. Proinflammatory cytokines, such as tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta, up-regulate Gb3 expression, increase sensitivity to VTs, and enhance VT action in developing disease. Currently, there is a growing interest in probiotics, given the increasing occurrence of antibiotic-resistant bacteria. In particular, much work on bifidobacteria among probiotics, regarded as microorganisms targeted for technological and therapeutic applications, has been performed. In Korea, the neutralizing effect of the culture supernatant of Bifidobacterium longum HY8001, Korean isolate, against the VTs from E. coli O157:H7 was found. Therefore, this study focused on the raveling of the inhibitory effect of B. longum HY8001 against VTs, through the interference B subunit of VTs and Gb3 interaction. Mice were inoculated intragastrically with B. longum HY8001 culture supernatant before and after challenge with E. coli O157:H7. Control mice were inoculated intragastrically only with E. coli O157:H7. Cytokine, TNF-alpha, and IL-1beta levels in sera and expression of their mRNA were decreased, and expression of Gb3 in renal tubular epithelial cells was reduced in mice treated with B. longum HY8001 culture supernatant. In competitive enzyme-linked immunosorbent assays (ELISAs), the culture supernatant of B. longum HY8001 primarily binds VTs to interfere the VTs with Gb3 interaction. These results suggest that soluble substance(s) in B. longum HY8001 culture supernatant may have inhibitory activity on the expression of Gb3, VT-Gb3 interaction, or both. Further study should be done to elucidate the property of soluble substances in B. longum HY8001 culture supernatant.
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Affiliation(s)
- S H Kim
- Department of Microbiology, College of Veterinary Medicine and School of Agricultural Biotechnology, Seoul National University, Suwon, Gyunggi, Korea
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55
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Abstract
E. coli O157:H7 can cause potentially lethal illness in hosts of all ages. These patients often are evaluated and treated by gastroenterologists. The treating physician should administer adequate hydration, usually parenterally, and avoid the use of antibiotics and antimotility agents. The physician needs to notify immediately the appropriate public health authorities of the diagnosis and to ensure that the isolate is recovered by the microbiologist and forwarded for molecular linkage analyses.
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Affiliation(s)
- P I Tarr
- Division of Gastroenterology, Children's Hospital and Regional Medical Center, Department of Pediatrics, University of Washington School of Medicine, Seattle, Washington, USA.
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56
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Kitova EN, Kitov PI, Bundle DR, Klassen JS. The observation of multivalent complexes of Shiga-like toxin with globotriaoside and the determination of their stoichiometry by nanoelectrospray Fourier-transform ion cyclotron resonance mass spectrometry. Glycobiology 2001; 11:605-11. [PMID: 11447140 DOI: 10.1093/glycob/11.7.605] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We show by nanoelectrospray ionization (nanoES) Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS) that it is possible to observe oligosaccharide-protein complexes with dissociation constants in the millimolar range, such as P(k) trisaccharide (globotriaoside) complexed with the Shiga-like toxin (SLT) of pathogenic E. coli. It is further demonstrated that nanoES/FT-ICR MS is an exquisite method to study quantitative aspects of the association of mono- and polyvalent oligosaccharide ligands with multimeric proteins, such as the SLTs. At increasing trisaccharide:protein ratios it was shown that the B(5 )toxin subunit complexes with 5 P(k) trisaccharides and only after all 5 copies of site 2 are essentially filled do any of the remaining 10 receptor sites become occupied. From the distribution of bound P(k)'s at the five binding sites, it was possible to establish association constants for each of the five sites and to confirm that binding occurs noncooperatively, the association constants for each site are identical and that compared to site 1, site 2 exhibits a tenfold higher affinity for the globotriaoside synthetic ligand 1. The facile identification of the occupancy of binding sites represents information that is not readily available by other techniques. This sensitive and rapid estimation of association constants for protein-ligand complexes, which are free of unpredictable secondary effects that plague enzyme linked assays, is likely to find wide application.
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Affiliation(s)
- E N Kitova
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2
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57
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Liu MZ, Fan HN, Lee YC. Chemical synthesis of a P(k)-antigenic globotriose analogue with a functionalized aglycon. Biochimie 2001; 83:693-8. [PMID: 11522399 DOI: 10.1016/s0300-9084(01)01300-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
6-Aminohexyl alpha-D-galactopyranosyl-(1-->4)-beta-D-galactopyranosyl-(1-->4)-beta-D-glucopyranoside (2), a globotriose analogue with a functionalized aglycon, was synthesized, using alpha-D-galactopyranosyluronic acid-(1-->4)-D-galactopyranosyluronic acid [di-GalA (3)] as the starting material, which is commercially available or can be readily prepared from pectin.
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Affiliation(s)
- M Z Liu
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA
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58
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Karpman D, Papadopoulou D, Nilsson K, Sjögren AC, Mikaelsson C, Lethagen S. Platelet activation by Shiga toxin and circulatory factors as a pathogenetic mechanism in the hemolytic uremic syndrome. Blood 2001; 97:3100-8. [PMID: 11342436 DOI: 10.1182/blood.v97.10.3100] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Thrombocytopenia caused by platelet consumption in thrombi is a major manifestation of hemolytic uremic syndrome (HUS) associated with Shiga toxin (Stx) producing Escherichia coli. Platelets have glycosphingolipid receptors capable of binding Stx, but a direct interaction between the toxin and platelets, leading to platelet activation, has not been reported. In this study, it is shown that Stx1 and its B (binding) subunit (Stx1B), at 10 pg/mL to 10 ng/mL, bound to platelets. Toxin was internalized in platelets within 2 hours. This led to increased platelet aggregation, as demonstrated by confocal microscopy. Preincubation of Stx1B with anti-Stx1 antibody inhibited this reaction. Stx1 induced morphologic changes in platelets seen on scanning electron microscopy. In the presence of platelets and tumor necrosis factor-pretreated human umbilical vein endothelial cells (HUVEC), Stx1 and Stx1B induced the binding of platelets to the endothelial cell membrane and were present at this binding site. Incubation of Stx1 and Stx1B with whole blood increased fibrinogen binding to platelets detected by flow cytometry. Fibrinogen binding was partially inhibited by preincubation with anti-Stx1. Stx1 increased platelet retention measured in a glass bead assay. In addition, plasma from 17 patients with HUS, taken during the acute phase of the disease, increased the retention of normal platelets and normalized after recovery. Taken together, the results of this investigation show that Stx1, Stx1B, and a factor or factors in the plasma of patients with HUS activate platelets. The presence of Stx1 at the binding site of platelets to HUVEC suggests that Stx may be directly involved in the prothrombotic state seen in HUS.
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Affiliation(s)
- D Karpman
- Department of Pediatrics, Lund University, Lund, Sweden.
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59
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Te Loo DMWM, Hinsbergh VWMVAN, Heuvel LPWJVANDEN, Monnens LAH. Detection of verocytotoxin bound to circulating polymorphonuclear leukocytes of patients with hemolytic uremic syndrome. J Am Soc Nephrol 2001; 12:800-806. [PMID: 11274241 DOI: 10.1681/asn.v124800] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
The epidemic form of hemolytic uremic syndrome (HUS) is the most common cause of acute renal failure in children and is characterized by a prodromal phase of sometimes bloody diarrhea. The role of verocytotoxin (VT)-producing Escherichia coli has been strongly implicated. Although antibodies against VT have been detected in the serum of patients with HUS, VT itself has never been detected in circulating blood. In this study, VT-2 was detected in the systemic circulation in 9 of 10 patients with the epidemic form of HUS. In those cases, VT-2 was bound exclusively to polymorphonuclear leukocytes (PMN). The detection of VT-2 bound to PMN was associated with the presence of diarrhea at the time the blood samples were obtained. The one patient for whom VT was not detected presented with atypical HUS. For 5 of the 10 patients with HUS who were studied, the time course of VT binding was analyzed; binding decreased in four patients. The finding of VT bound to PMN in the systemic circulation of patients with HUS is important for a clearer understanding of the pathogenesis of HUS and suggests new approaches for treatment in the future.
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Affiliation(s)
| | - Victor W M VAN Hinsbergh
- Gaubius Laboratory TNO-PG, Leiden, The Netherlands
- Institute for Cardiovascular Research, Vrije Universiteit, Amsterdam, The Netherlands
| | | | - Leo A H Monnens
- Department of Pediatrics, University Hospital Nijmegen, Nijmegen, The Netherlands
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60
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Stock K, Dummer J, Scott M, Davis S, Pierson R. Hemorrhagic colitis due to a novel Escherichia coli serotype (0121:H19) in a transplant patient. Transpl Int 2001. [DOI: 10.1111/j.1432-2277.2001.tb00008.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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61
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Thompson GS, Shimizu H, Homans SW, Donohue-Rolfe A. Localization of the binding site for the oligosaccharide moiety of Gb3 on verotoxin 1 using NMR residual dipolar coupling measurements. Biochemistry 2000; 39:13153-6. [PMID: 11052667 DOI: 10.1021/bi001394+] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
By use of NMR residual dipolar coupling measurements in a dilute liquid-crystalline solvent, the solution structure has been determined of the complex between the oligosaccharide moiety of globotriaosylceramide (Gb(3)-OS) and the B-subunit homopentamer of verotoxin 1 (VTB). The dipolar coupling data indicate that Gb(3)-OS binds in a single binding site per monomer, which is identical to one of three sites inferred from the X-ray structure of the same complex. We find no evidence within experimental error for occupancy at either of the two additional binding sites observed per monomer in the crystal structure.
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Affiliation(s)
- G S Thompson
- School of Biochemistry and Molecular Biology, University of Leeds, LS2 9JT, U.K
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62
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Shimazu T, Shimaoka M, Sugimoto H, Taenaka N, Hasegawa T. Does blood type B protect against haemolytic uraemic syndrome? An analysis of the 1996 Sakai outbreak of Escherichia coli O157:H7 (VTEC O157) infection. The Osaka HUS Critical Care Study Group. J Infect 2000; 41:45-9. [PMID: 10942639 DOI: 10.1053/jinf.2000.0677] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVES Expression of the P1 blood type antigen is suggested to have a protective effect against post-enteropathic haemolytic uraemic syndrome (HUS). The B blood type may also protect against HUS, since terminal trisaccharide sequences similar to those of the B blood type determinants are reported to have an affinity to Vero cytotoxin that is 23% as strong as that of the P1 determinants. Thus, we studied whether ABO blood types were related to the occurrence or severity of HUS. METHODS We obtained clinical and laboratory data of 49 HUS patients treated in 14 critical care facilities during the 1996 Escherichia coli O157:H7 outbreak in Sakai, Japan. We retrospectively studied whether ABO blood types were related to the occurrence or severity of HUS. RESULTS The numbers of patients with blood types A, B, O or AB were 29, 8, 12, and 0, respectively. For each blood type, the number of patients with severe renal complications was 16, 6, 9, and 0, respectively. The distribution of blood types among the HUS patients deviated from a population-based distribution of blood types (P<0.05, Chi-squared test); i.e., the frequency of the A blood phenotype was significantly higher among our HUS patients. However, there was no significant difference in the frequency of patients with the A antigen (A and AB blood groups) among our HUS patients, whereas the frequency of B antigen expression was significantly lower (P<0.05, Chi-squared test). The risk of severe renal complications did not appear to be related to ABO blood types. CONCLUSIONS Our data suggest that expression of the B antigen has a protective effect against the onset of HUS, but that it does not affect the severity of the disease.
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Affiliation(s)
- T Shimazu
- Department of Traumatology and Acute Critical Medicine, Osaka University Medical School
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63
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Brigotti M, Carnicelli D, Accorsi P, Rizzi S, Montanaro L, Sperti S. 4-Aminopyrazolo[3,4-d]pyrimidine (4-APP) as a novel inhibitor of the RNA and DNA depurination induced by Shiga toxin 1. Nucleic Acids Res 2000; 28:2383-8. [PMID: 10871371 PMCID: PMC102733 DOI: 10.1093/nar/28.12.2383] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Shiga toxin 1 (Stx1) catalyses the removal of a unique and specific adenine from 28S RNA in ribosomes (RNA-N-glycosidase activity) and the release of multiple adenines from DNA (DNA glycosylase activity). Added adenine behaves as an uncompetitive inhibitor of the RNA-N-glycosidase reaction binding more tightly to the Stx1-ribosome complex than to the free enzyme. Several purine derivatives and analogues have now been assayed as inhibitors of Stx1. Most of the compounds showed only minor differences in the rank order of activity on the two enzymatic reactions catalysed by Stx1. The survey highlights the importance of the amino group in the 6-position of the pyrimidine ring of adenine. Shifting (2-aminopurine) or substituting (hypoxanthine, 6-mercapto-purine, 6-methylpurine) the group greatly decreases the inhibitory power. The presence of a second ring, besides the pyrimidine one, is strictly required. Substitution, by introducing an additional nitrogen, of the imidazole ring of adenine with triazole leads to loss of inhibitory power, while rearrangement of the nitrogen atoms of the ring from the imidazole to the pyrazole configuration greatly enhances the inhibitory power. Thus 4-aminopyrazolo[3,4-d]pyrimidine (4-APP), the isomer of adenine with the five-membered ring in the pyrazole configuration, is by far the most potent inhibitor of both enzymatic reactions catalysed by Stx1. This finding opens perspectives on therapeutic strategies to protect endothelial renal cells once endocytosis of Stx1 has occurred (haemolytic uraemic syndrome). In the RNA-N-glycosidase reaction 4-APP binds, as adenine, predominantly to the Stx1-ribosome complex (uncompetitive inhibition), while inhibition of the DNA glycosylase activity by both inhibitors is of the mixed type.
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Affiliation(s)
- M Brigotti
- Dipartimento di Patologia Sperimentale dell'Università degli Studi di Bologna, Via San Giacomo 14, I-40126 Bologna, Italy
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64
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Craig-Mylius KA, Weiss AA. Antibacterial agents and release of periplasmic pertussis toxin from Bordetella pertussis. Antimicrob Agents Chemother 2000; 44:1383-6. [PMID: 10770786 PMCID: PMC89879 DOI: 10.1128/aac.44.5.1383-1386.2000] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pertussis toxin accumulates in the periplasm of Bordetella pertussis prior to secretion, and we examined its fate following treatment with antimicrobial agents. Both antibiotics that inhibit protein synthesis (erythromycin and chloramphenicol), transcription (rifampin), or cell wall biosynthesis (cefoperazone and piperacillin) and magnesium sulfate (which inhibits transcription of pertussis toxin, but not bacterial growth) did not prevent release of preformed toxin. In contrast, agents that affect bacterial membranes, such as polymyxin B, lidocaine, procaine, and ethanol, inhibited release of preformed pertussis toxin. These results suggest new protein synthesis is not required for pertussis toxin secretion, but a functional membrane complex is required.
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Affiliation(s)
- K A Craig-Mylius
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati, Cincinnati, Ohio 45267-0524, USA
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65
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Hu Z, Shimokawa T, Ohno T, Kimura G, Mawatari SS, Kamitsuna M, Yoshikawa Y, Masuda S, Takada K. Characterization of norfloxacine release from tablet coated with a new pH-sensitive polymer, P-4135F. J Drug Target 2000; 7:223-32. [PMID: 10680978 DOI: 10.3109/10611869909085505] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A new pH-sensitive polymer, P-4135F, was evaluated as a colon delivery device for norfloxacine (NFLX) which is used for the therapy of patients with Vero toxin-producing Escherichia coli gastroenteritis. P-4135F has a dissolution threshold pH of 7.2 which is higher than the conventional pH-sensitive polymers, Eudragit S100 and L100. To compare the dissolution site of P-4135F coated tablets with other enteric polymer coatings, mini-tablets containing sodium fluorescein (FL) as a model drug were prepared by coating them with the three polymers. After oral administration of FL mini-tablets to rats, the first-appearance time, Ti, of FL into the systemic circulation was measured. The Tis were 0.7+/-0.2 h for Eudragit L100, 1.8+/-0.4 h for S100 and 2.0+/-0.3 h for P-4135F. Direct inspection of the dissolution process of the FL mini-tablets after oral administration to rats was performed by abdominal incision studies. All of the coated FL mini-tablets started to dissolve in the rat ileum. The dissolution sites were identified to be proximal to the ileocecal junction for P-4135F, at the middle part of the ileum for Eudragit S100 and at the proximal part of the ileum for Eudragit L100. NFLX tablets with different membrane thicknesses of P-4135F were prepared and were orally administered to beagle dogs. The colon delivery efficiency was evaluated by measuring the Ti of NFLX into the systemic circulation. The mean Tis were 1.33+/-0.33 h for 56.8+/-0.5 microm membranes, 3.75+/-0.25 h for 64.6+/-0.7 microm membranes, 4.00+/-1.00 h for 70.5+/-0.5 microm membranes and 3.00+/-1.00 h for 74.9+/-0.4 microm membranes. By comparing the Ti, 4.33+/-0.33 h, obtained after oral administration of NFLX in a pressure-controlled colon delivery capsule, and the colon arrival time, 3.5+/-0.3 h, determined by a sulfasalazine test in beagle dogs. P-4135F coated NFLX tablets appeared to dissolve and disintegrate before reaching the colon. Studies using rats and beagle dogs have suggested that P-4135F dissolves in the lower part of the small intestine, i.e., the ileum. These studies also suggest that this new polymer will be useful for the delivery of NFLX to the lower part of the small intestine.
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Affiliation(s)
- Z Hu
- Department of Pharmacokinetics, Kyoto Pharmaceutical University, Japan
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66
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Ling H, Pannu NS, Boodhoo A, Armstrong GD, Clark CG, Brunton JL, Read RJ. A mutant Shiga-like toxin IIe bound to its receptor Gb(3): structure of a group II Shiga-like toxin with altered binding specificity. Structure 2000; 8:253-64. [PMID: 10745005 DOI: 10.1016/s0969-2126(00)00103-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
BACKGROUND Shiga-like toxins (SLTs) are produced by the pathogenic strains of Escherichia coli that cause hemorrhagic colitis and hemolytic uremic syndrome. These diseases in humans are generally associated with group II family members (SLT-II and SLT-IIc), whereas SLT-IIe (pig edema toxin) is central to edema disease of swine. The pentameric B-subunit component of the majority of family members binds to the cell-surface glycolipid globotriaosyl ceramide (Gb(3)), but globotetraosyl ceramide (Gb(4)) is the preferred receptor for SLT-IIe. A double-mutant of the SLT-IIe B subunit that reverses two sequence differences from SLT-II (GT3; Gln65-->Glu, Lys67-->Gln, SLT-I numbering) has been shown to bind more strongly to Gb(3) than to Gb(4). RESULTS To understand the molecular basis of receptor binding and specificity, we have determined the structure of the GT3 mutant B pentamer, both in complex with a Gb(3) analogue (2.0 A resolution; R = 0.155, R(free) = 0.194) and in its native form (2.35 A resolution; R = 0.187, R(free) = 0.232). CONCLUSIONS These are the first structures of a member of the medically important group II Shiga-like toxins to be reported. The structures confirm the previous observation of multiple binding sites on each SLT monomer, although binding site 3 is not occupied in the GT3 structure. Analysis of the binding properties of mutants suggests that site 3 is a secondary Gb(4)-binding site. The two mutated residues are located appropriately to interact with the extra betaGalNAc residue on Gb(4). Differences in the binding sites provide a molecular basis for understanding the tissue specificities and pathogenic mechanisms of members of the SLT family.
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Affiliation(s)
- H Ling
- Department of Biochemistry, University of Alberta, Edmonton, T6G 2H7, Canada
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67
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Takenaga M, Igarashi R, Higaki M, Nakayama T, Yuki K, Mizushima Y. Effect of a soluble pseudo-receptor on verotoxin 2-induced toxicity. J Infect Chemother 2000; 6:21-5. [PMID: 11810526 DOI: 10.1007/s101560050044] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/1999] [Accepted: 10/07/1999] [Indexed: 12/21/2022]
Abstract
To neutralize the toxicity of verotoxin (VT) produced by Escherichia coli type O-157, a soluble pseudo-receptor (Lyso Gb3) was synthesized with the deacylated form of the natural receptor, globotrisylceramide (Galalpha 1-4Galbeta1-4-glucosylceramide; Gb3). In this study, we evaluated the characteristics and pharmacological effects of Lyso Gb3, using VT2. It was confirmed that Lyso Gb3 specifically recognized VT2. Lyso Gb3 itself had little influence on the in-vitro growth of Vero cells, but markedly augmented VT2-induced cytotoxicity. In addition, the VT2-induced killing of mice was not decreased, but was, rather, increased by Lyso Gb3. These results indicate that the soluble pseudo-receptor Lyso Gb3 recognized VT2. However, it did not reduce, but, rather, enhanced, VT2-induced toxicity in the presence of the natural receptor, although Lyso Gb3 alone had no toxicity.
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Affiliation(s)
- M Takenaga
- Institute of Medical Science, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamae-ku, Kawasaki 216-8512, Japan.
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Paton AW, Morona R, Paton JC. A new biological agent for treatment of Shiga toxigenic Escherichia coli infections and dysentery in humans. Nat Med 2000; 6:265-70. [PMID: 10700227 DOI: 10.1038/73111] [Citation(s) in RCA: 164] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Gastrointestinal disease caused by Shiga toxin-producing bacteria (such as Escherichia coli O157:H7 and Shigella dysenteriae) is often complicated by life-threatening toxin-induced systemic sequelae, including hemolytic-uremic syndrome. Such infections can now be diagnosed very early in the course of the disease, but at present no effective therapeutic intervention is possible. Here, we constructed a recombinant bacterium that displayed a Shiga toxin receptor mimic on its surface, and it adsorbed and neutralized Shiga toxins with very high efficiency. Moreover, oral administration of the recombinant bacterium completely protected mice from challenge with an otherwise 100%-fatal dose of Shiga toxigenic E. coli. Thus, the bacterium shows great promise as a 'probiotic' treatment for Shiga toxigenic E. coli infections and dysentery.
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Affiliation(s)
- A W Paton
- Molecular Microbiology Unit, Women's and Children's Hospital, North Adelaide, S.A., 5006, Australia
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69
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Novicki TJ, Daly JA, Mottice SL, Carroll KC. Comparison of sorbitol MacConkey agar and a two-step method which utilizes enzyme-linked immunosorbent assay toxin testing and a chromogenic agar to detect and isolate enterohemorrhagic Escherichia coli. J Clin Microbiol 2000; 38:547-51. [PMID: 10655343 PMCID: PMC86145 DOI: 10.1128/jcm.38.2.547-551.2000] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/1999] [Accepted: 09/28/1999] [Indexed: 11/20/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) and specifically serotype O157:H7 are a significant cause of hemorrhagic gastrointestinal disease and the hemolytic uremic syndrome. Methods currently used in clinical microbiology labs, such as sorbitol-MacConkey (SMAC) agar, reliably detect only O157:H7. We have evaluated a two-step method that has the potential to identify and isolate all EHEC serotypes, including serotype O157:H7. This method utilizes a chromogenic selective-differential medium for the isolation of E. coli together with an enzyme-linked immunosorbent assay (ELISA) that detects the Shiga-like toxins Stx1 and Stx2. Both are commercially available and usable in a wide range of clinical microbiology laboratories. Compared to a Vero cell cytotoxic assay, SMAC had sensitivities of 23.5% for the identification of all EHEC serotypes and of 50.0% for the identification of O157:H7 alone. The two-step method had sensitivities of 76.5 and 100%, respectively. The ELISA alone had a sensitivity of 82.4% in the detection of Stx1 and Stx2. The specificity was 100% in all cases. Overall, 14 EHEC isolates were obtained: 8 (58%) O157:H7, 2 (14%) O26, 2 (14%) O111:NM, 1 (7%) O103:H2, and 1 (7%) O121:H19. All but one were isolated during the months of May to September. The two-step method was found to be considerably more expensive than SMAC for both positive and negative samples.
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Affiliation(s)
- T J Novicki
- Department of Pathology, University of Utah School of Medicine and ARUP Laboratories, Salt Lake City, Utah 84113, USA.
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70
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Takeda T, Yoshino K, Adachi E, Sato Y, Yamagata K. In vitro assessment of a chemically synthesized Shiga toxin receptor analog attached to chromosorb P (Synsorb Pk) as a specific absorbing agent of Shiga toxin 1 and 2. Microbiol Immunol 1999; 43:331-7. [PMID: 10385199 DOI: 10.1111/j.1348-0421.1999.tb02413.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A synthetic analog of Shiga toxin (Stx) receptor (Synsorb Pk) was quantitatively assessed to determine whether it can protect human renal adenocarcinoma cells (ACHN cells) from the cytotoxicity of Stx1 and Stx2 by coincubation experiments. Coincubation of 100 and 20 ng of Stxl and Stx2 with 50 mg of Synsorb Pk for 1 hr at 37 C in 1 ml of Eagle's Minimum Essential Medium supplemented with 1% (v/v) non-essential amino acid and 10% (v/v) fetal calf serum protected 50% of the cells from the cytotoxic effect. Chromosorb P, an inert matrix control, did not absorb the Stxs at all. Heat-treatment (boiled for 10 min) to Synsorb Pk caused a 50% decrease in Stx2-binding activity, but did not effect the Stx1 binding. Further, Stxs bound to Synsorb Pk could be demonstrated. When 20 mg of Synsorb Pk was coincubated for 30 min at 37 C in 1 ml of phosphate-buffered saline with 1 and 10 ng or more of Stx1 or Stx2, respectively, the toxins could be detected on the surface when the bound toxins on Synsorb Pk were used as the solid phase in enzyme immunoassay. The amount of 100 ng/ml of both Stxl and Stx2 appeared to saturate 20 mg/ml of Synsorb Pk after coincubating for 30 min at 37 C. While assessing the Stxs' binding activity to Synsorb Pk, it was demonstrated that Stxl had a higher affinity to Pk trisaccharide than Stx2. These observations provide useful information on the effectiveness of Synsorb Pk to trap and eliminate free Stxs produced in the gut of patients infected by Stx-producing Escherichia coli, and to prevent the progression of hemorrhagic colitis to hemolytic uremic syndrome.
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Affiliation(s)
- T Takeda
- Department of Infectious Diseases Research, National Children's Medical Research Center, Tokyo, Japan.
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71
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Keusch GT. The rediscovery of Shiga toxin and its role in clinical disease. JAPANESE JOURNAL OF MEDICAL SCIENCE & BIOLOGY 1999; 51 Suppl:S5-22. [PMID: 10211432 DOI: 10.7883/yoken1952.51.supplement1_s5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- G T Keusch
- Division of Geographic Medicine and Infectious Diseases, Tupper Research Institute, New England Medical Center, Boston, Massachusetts 02111, USA
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72
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Takeda T. Strategy to prevent the progression of enterohemorrhagic Escherichia coli O157 infection to hemolytic uremic syndrome. JAPANESE JOURNAL OF MEDICAL SCIENCE & BIOLOGY 1999; 51 Suppl:S124-8. [PMID: 10211445 DOI: 10.7883/yoken1952.51.supplement1_s124] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- T Takeda
- Department of Infectious Diseases Research, National Children's Medical Research Center, Tokyo, Japan
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73
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74
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Louie M, Read S, Simor AE, Holland J, Louie L, Ziebell K, Brunton J, Hii J. Application of multiplex PCR for detection of non-O157 verocytotoxin-producing Escherichia coli in bloody stools: identification of serogroups O26 and O111. J Clin Microbiol 1998; 36:3375-7. [PMID: 9774599 PMCID: PMC105335 DOI: 10.1128/jcm.36.11.3375-3377.1998] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Primers were designed to amplify sequences of verocytotoxin genes and eaeA genes of Escherichia coli O26:H11, O111:H8, and O157:H7 in a multiplex PCR assay. This assay successfully detected E. coli O26:H11 in bloody stool specimens in which other enteric pathogens were not detected by culture-based methods. Rapid assays to detect non-O157:H7 verocytotoxin-producing E. coli is important to improve methods for the etiologic diagnosis of hemorrhagic colitis.
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Affiliation(s)
- M Louie
- Department of Microbiology, SD Laboratory Services, Sunnybrook Health Science Centre, Toronto, Ontario, Canada
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75
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Wong S, Yam WC, Leung P, Woo P, Yuen KY. Verocytotoxin-producing Escherichia coli infection: The Hong Kong experience. J Gastroenterol Hepatol 1998; 13:S289-S293. [PMID: 28976670 DOI: 10.1111/j.1440-1746.1998.tb01895.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
Infection by verocytotoxin-producing Escherichia coli (VTEC) is prevalent in many parts of the world but relatively uncommon in Asia, except Japan. A territory wide screening for VTEC (April to August 1996) in diarrhoeal stool samples sent to six hospital microbiology laboratories in Hong Kong revealed only four isolates of VTEC and one isolate of E. coli O157:NM in 1003 specimens (incidence 0.5%). Two isolates carrying the verocytotoxin (VT) genes belonged to the O157:H7 serotype while the other two were non-O157. One non-toxigenic E. coli O157:NM was also isolated. All isolates positive for VT genes by polymerase chain reaction (PCR) were also positive for the Vero toxin assayed by the Vero cell culture. The 97 kDa eaeA outer membrane protein gene and 60 MDa fimbrial plasmid pcVD419 were present only in the two O157:H7 isolates. All patients presented with uncomplicated watery diarrhoea; no one suffered from haemorrhagic colitis or the haemolytic uraemic syndrome. All patients recovered uneventfully without antibiotic treatment. Although VTEC infection is still uncommon in Hong Kong, continued surveillance is essential to prevent future outbreaks.
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Affiliation(s)
- Ssy Wong
- Division of Infectious Disease, Department of Microbiology, The University of Hong KongDepartment of Nursing and Health Sciences, the Hong Kong Polytechnic University, Hong Kong
| | - W C Yam
- Division of Infectious Disease, Department of Microbiology, The University of Hong KongDepartment of Nursing and Health Sciences, the Hong Kong Polytechnic University, Hong Kong
| | - Phm Leung
- Division of Infectious Disease, Department of Microbiology, The University of Hong KongDepartment of Nursing and Health Sciences, the Hong Kong Polytechnic University, Hong Kong
| | - Pcy Woo
- Division of Infectious Disease, Department of Microbiology, The University of Hong KongDepartment of Nursing and Health Sciences, the Hong Kong Polytechnic University, Hong Kong
| | - K Y Yuen
- Division of Infectious Disease, Department of Microbiology, The University of Hong KongDepartment of Nursing and Health Sciences, the Hong Kong Polytechnic University, Hong Kong
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76
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Abstract
Escherichia coli O157 was first identified as a human pathogen in 1982. One of several Shiga toxin-producing serotypes known to cause human illness, the organism probably evolved through horizontal acquisition of genes for Shiga toxins and other virulence factors. E. coli O157 is found regularly in the faeces of healthy cattle, and is transmitted to humans through contaminated food, water, and direct contact with infected people or animals. Human infection is associated with a wide range of clinical illness, including asymptomatic shedding, non-bloody diarrhoea, haemorrhagic colitis, haemolytic uraemic syndrome, and death. Since laboratory practices vary, physicians need to know whether laboratories in their area routinely test for E. coli O157 in stool specimens. Treatment with antimicrobial agents remains controversial: some studies suggest that treatment may precipitate haemolytic uraemic syndrome, and other studies suggest no effect or even a protective effect. Physicians can help to prevent E. coli O157 infections by counselling patients about the hazards of consuming undercooked ground meat or unpasteurised milk products and juices, and about the importance of handwashing to prevent the spread of diarrhoeal illness, and by informing public-health authorities when they see unusual numbers of cases of bloody diarrhoea or haemolytic uraemic syndrome.
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Affiliation(s)
- P S Mead
- Foodborne and Diarrheal Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
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77
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Fujii J, Kinoshita Y, Yamada Y, Yutsudo T, Kita T, Takeda T, Yoshida S. Neurotoxicity of intrathecal Shiga toxin 2 and protection by intrathecal injection of anti-Shiga toxin 2 antiserum in rabbits. Microb Pathog 1998; 25:139-46. [PMID: 9790873 DOI: 10.1006/mpat.1998.0220] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The initial brain lesions in rabbits given intravenous Shiga toxin 2 (Stx2) were noted at 24 h in an area around the third ventricle (Fujii et al., Infect Immun 1996, 64: 5053-60). This result implied that Stx2 is present in the cerebrospinal fluid (CSF) despite the fact that the toxin was administered intravenously. We measured Stx2 activity in CSF by using a Vero cell cytotoxicity assay at various times after an intravenous injection of Stx2. Stx2 was detected from 2 h after the injection, and its concentration in CSF remained at a high level for a further 6 h. Fifty percent lethal doses (LD 50) of Stx2 were measured in rabbits after intravenous and intrathecal Stx2 injections; The LD 50 after an intrathecal injection of Stx2 was 0. 36 microg/kg, which was 9.2-fold lower than that of an intravenous injection of Stx2 (3.4 microg/kg). Magnetic resonance images obtained after an intrathecal Stx2 injection (5 microg/kg) were compared with those obtained after an intravenous Stx2 injection (5 microg/kg). At 48 h, the cerebellar lesions had spread from the area in contact with the CSF on a T2-weighted image, which suggests that the intrathecal Stx2 may invade the cerebellum directly. We then examined whether anti-Stx2 antiserum injected intrathecally protects rabbits against brain damage. Eighty percent of the rabbits infected with Stx2 at 5 microg/kg died within 8 days from brain damage. Rabbit anti-Stx2 sera (with titres of x16 and x64 by the Ouchterlony precipitation method) were administered into the CSF space through the cisterna magna. All the rabbits ( n=10) survived when they were given an intrathecal injection of rabbit anti-Stx2 antiserum 2 h before the intravenous injection of Stx2. Our results suggest that a leakage of Stx2 into the CSF from the choroid plexus causes brain damage, and that an intrathecal injection of anti-Stx2 antiserum could be a therapy for acute encephalopathy caused by Stx2-producing Escherichia coli.
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Affiliation(s)
- J Fujii
- Department of Microbiology, University of Occupational and Environmental Health, Kitakyushu, 807-8555, Japan
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78
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Shimizu H, Field RA, Homans SW, Donohue-Rolfe A. Solution structure of the complex between the B-subunit homopentamer of verotoxin VT-1 from Escherichia coli and the trisaccharide moiety of globotriaosylceramide. Biochemistry 1998; 37:11078-82. [PMID: 9693003 DOI: 10.1021/bi980946+] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We report the solution structure of the carbohydrate-binding B subunit of verotoxin VT-1 (VTB) from enterohemorrhagic Escherichia coli in association with the trisaccharide Galalpha1-4Galbeta1-4Glcbeta1-O-trimethylsilylethyl , determined by use of stable isotope-assisted NMR techniques. In contrast to the crystal structure of the complex which predicts three binding sites per monomer, only one of these sites is observed with substantial occupancy by the trisaccharide in solution.
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Affiliation(s)
- H Shimizu
- Centre for Biomolecular Sciences, University of St. Andrews, FIFE, UK
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79
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Abstract
The vascular endothelial injury with its consequent activation is actively involved in inflammation and promotion of a procoagulant state, which are likely to be of major importance in the pathogenesis of various disorders, including renal thrombotic microangiopathy. This study briefly reviews the consequences of glomerular endothelial cell injury or activation, as shown by recent experimental data.
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Affiliation(s)
- M Nangaku
- Division of Nephrology and Endocrinology, University of Tokyo School of Medicine, Japan.
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80
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Paton JC, Paton AW. Pathogenesis and diagnosis of Shiga toxin-producing Escherichia coli infections. Clin Microbiol Rev 1998; 11:450-79. [PMID: 9665978 PMCID: PMC88891 DOI: 10.1128/cmr.11.3.450] [Citation(s) in RCA: 962] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Since their initial recognition 20 years ago, Shiga toxin-producing Escherichia coli (STEC) strains have emerged as an important cause of serious human gastrointestinal disease, which may result in life-threatening complications such as hemolytic-uremic syndrome. Food-borne outbreaks of STEC disease appear to be increasing and, when mass-produced and mass-distributed foods are concerned, can involve large numbers of people. Development of therapeutic and preventative strategies to combat STEC disease requires a thorough understanding of the mechanisms by which STEC organisms colonize the human intestinal tract and cause local and systemic pathological changes. While our knowledge remains incomplete, recent studies have improved our understanding of these processes, particularly the complex interaction between Shiga toxins and host cells, which is central to the pathogenesis of STEC disease. In addition, several putative accessory virulence factors have been identified and partly characterized. The capacity to limit the scale and severity of STEC disease is also dependent upon rapid and sensitive diagnostic procedures for analysis of human samples and suspect vehicles. The increased application of advanced molecular technologies in clinical laboratories has significantly improved our capacity to diagnose STEC infection early in the course of disease and to detect low levels of environmental contamination. This, in turn, has created a potential window of opportunity for future therapeutic intervention.
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Affiliation(s)
- J C Paton
- Molecular Microbiology Unit, Women's and Children's Hospital, North Adelaide, Australia.
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81
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Abstract
The microbe-host interface is currently in focus because of attempts to develop infection therapy in humans based on either natural receptor saccharide (respiratory and gastrointestinal disease) or sophisticated sialic acid analogues designed from crystal structures (influenza). Most of the known host receptors for microbes are glycoconjugates, and the diversity and selectivity of host tissue glycosylation allow for the tropism of infections. However, among the many binding specificities detected so far, the biological role has been proven only in a few infectious model systems. The existence of multiple specificities of a single microbe is both a complicating factor and a challenge, requiring expanded research with a special demand on glycoscience.
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Affiliation(s)
- K A Karlsson
- Institute of Medical Biochemistry, Göteborg University, Sweden.
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82
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83
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Mulvey G, Vanmaele R, Mrazek M, Cahill M, Armstrong GD. Affinity purification of Shiga-like toxin I and Shiga-like toxin II. J Microbiol Methods 1998. [DOI: 10.1016/s0167-7012(98)00028-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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84
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Ling H, Boodhoo A, Hazes B, Cummings MD, Armstrong GD, Brunton JL, Read RJ. Structure of the shiga-like toxin I B-pentamer complexed with an analogue of its receptor Gb3. Biochemistry 1998; 37:1777-88. [PMID: 9485303 DOI: 10.1021/bi971806n] [Citation(s) in RCA: 353] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Shiga-like toxin I (SLT-I) is a virulence factor of Escherichia coli strains that cause disease in humans. Like other members of the Shiga toxin family, it consists of an enzymatic (A) subunit and five copies of a binding subunit (the B-pentamer). The B-pentamer binds to a specific glycolipid, globotriaosylceramide (Gb3), on the surface of target cells and thereby plays a crucial role in the entry of the toxin. Here we present the crystal structure at 2.8 A resolution of the SLT-I B-pentamer complexed with an analogue of the Gb3 trisaccharide. The structure reveals a surprising density of binding sites, with three trisaccharide molecules bound to each B-subunit monomer of 69 residues. All 15 trisaccharides bind to one side of the B-pentamer, providing further evidence that this side faces the cell membrane. The structural model is consistent with data from site-directed mutagenesis and binding of carbohydrate analogues, and allows the rational design of therapeutic Gb3 analogues that block the attachment of toxin to cells.
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Affiliation(s)
- H Ling
- Department of Biochemistry, University of Alberta, Edmonton, Canada
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85
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Abstract
Enterohemorrhagic Escherichia coli has been responsible for an increasing number of large food-borne outbreaks of bloody diarrhea and hemolytic uremic syndrome. Recent developments in our understanding of the pathogenesis of disease due to enterhemorrhagic E. coli include the description of a pathogenicity island, a type III secretion system and potential plasmid-encoded virulence factors. Recent developments in our understanding of the epidemiology include a recognition of a widening spectrum of vehicles.
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Affiliation(s)
- J B Kaper
- Center for Vaccine Development,University of Maryland School of Medicine, 685 West Baltimore St., Baltimore, Maryland 21201-1509, USA.
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86
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Abstract
Escherichia coli is the predominant nonpathogenic facultative flora of the human intestine. Some E. coli strains, however, have developed the ability to cause disease of the gastrointestinal, urinary, or central nervous system in even the most robust human hosts. Diarrheagenic strains of E. coli can be divided into at least six different categories with corresponding distinct pathogenic schemes. Taken together, these organisms probably represent the most common cause of pediatric diarrhea worldwide. Several distinct clinical syndromes accompany infection with diarrheagenic E. coli categories, including traveler's diarrhea (enterotoxigenic E. coli), hemorrhagic colitis and hemolytic-uremic syndrome (enterohemorrhagic E. coli), persistent diarrhea (enteroaggregative E. coli), and watery diarrhea of infants (entero-pathogenic E. coli). This review discusses the current level of understanding of the pathogenesis of the diarrheagenic E. coli strains and describes how their pathogenic schemes underlie the clinical manifestations, diagnostic approach, and epidemiologic investigation of these important pathogens.
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Affiliation(s)
- J P Nataro
- Department of Medicine, University of Maryland School of Medicine, Baltimore 21201, USA.
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87
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Hansen HC, Haataja S, Finne J, Magnusson G. Di-, Tri-, and Tetravalent Dendritic Galabiosides That Inhibit Hemagglutination byStreptococcus suisat Nanomolar Concentration. J Am Chem Soc 1997. [DOI: 10.1021/ja970859p] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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88
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Nilsson UJ, Heerze LD, Liu YC, Armstrong GD, Palcic MM, Hindsgaul O. Immobilization of reducing sugars as toxin binding agents. Bioconjug Chem 1997; 8:466-71. [PMID: 9258442 DOI: 10.1021/bc9700603] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A simple and economical procedure for the attachment of reducing sugars to aminated solid supports has been developed. Reaction of the amino groups on the solid support with p-nitrophenyl chloroformate, followed by 1,6-hexanediamine, yields a chain-extended amine to which reducing sugars can be attached while remaining accessible to macromolecules. Immobilization of the reducing sugars involves a simple incubation followed by trapping of the resulting glycosylamine with acetic anhydride and recovery of the unreacted sugar by filtration. This technique was used to immobilize lactose and sialyllactose onto silylaminated Chromosorb P, producing solid supports that effectively neutralized the activity of cholera toxin from Vibrio cholerae and heat-labile enterotoxin of enterotoxigenic Escherichia coli. The general applicability of such solid supports for toxin neutralization was further demonstrated by immobilization of the enzymatically synthesized alpha Gal(1-3) beta Gal(1-4)Glc trisaccharide, which produced a support that efficiently neutralized toxin A of Clostridium difficile. The results from this study suggest that these solid supports have the potential to serve as inexpensive therapeutics for bacterial toxin-mediated diarrheal diseases.
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Affiliation(s)
- U J Nilsson
- Department of Chemistry, University of Alberta, Edmonton, Canada
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89
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Richardson JM, Evans PD, Homans SW, Donohue-Rolfe A. Solution structure of the carbohydrate-binding B-subunit homopentamer of verotoxin VT-1 from E. coli. NATURE STRUCTURAL BIOLOGY 1997; 4:190-3. [PMID: 9164458 DOI: 10.1038/nsb0397-190] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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90
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Feizi T, Bundle D. The coming of age for oligosaccharide ligands and databases for saccharide structures. Curr Opin Struct Biol 1996; 6:659-62. [PMID: 8913689 DOI: 10.1016/s0959-440x(96)80033-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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91
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Lissner R, Schmidit H, Karch H. A standard immunoglobulin preparation produced from bovine colostra shows antibody reactivity and neutralization activity against Shiga-like toxins and EHEC-hemolysin of Escherichia coli O157:H7. Infection 1996; 24:378-83. [PMID: 8923050 DOI: 10.1007/bf01716084] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Enterohemorrhagic Escherichia coli (EHEC) causes a variety of clinical conditions, the most important being hemorrhagic colitis and hemolytic uremic syndrome. A curative therapy of EHEC diseases is not yet feasible. This study investigates the antibody reactivity of Lactobin, a standardized immunoglobulin (Ig) preparation, obtained from the colostra of non-immunized cows. Three different batches of Lactobin exhibited equally high titers of specific antibodies against Shiga-like toxins (SLTs, verocytotoxins) and EHEC hemolysin (EHEC-Hly) produced by E. coli O157. In addition, Lactobin blocked the cytotoxic effect of SLT-I and SLT-II on Vero cell monolayers and inhibited the cytolytic effects of EHEC-Hly on human erythrocytes. Since Lactobin contains high levels of antibodies and neutralizing activity against important virulence factors of EHEC O157, this drug has potential use in the treatment of diarrhea and the prevention of EHEC-associated hemolytic uremic syndrome.
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Affiliation(s)
- R Lissner
- Biotest Pharma GmbH, Dreieich, Germany
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92
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Karch H. Control of enterohaemorrhagic Escherichia coli infection: the need for a network involving microbiological laboratories and clinical and public health institutions. Eur J Clin Microbiol Infect Dis 1996; 15:276-80. [PMID: 8781876 DOI: 10.1007/bf01695657] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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