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Zhu W, Wu C, Sun X, Zhang A, Zhu J, Hua Y, Chen H, Jin M. Characterization of Streptococcus suis serotype 2 isolates from China. Vet Microbiol 2013; 166:527-34. [PMID: 23876933 DOI: 10.1016/j.vetmic.2013.06.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Revised: 06/04/2013] [Accepted: 06/08/2013] [Indexed: 11/28/2022]
Abstract
Streptococcus suis (S. suis) is a major pathogen in the pig industry and an important zoonotic agent that causes severe invasive diseases in humans. Previous studies based on multilocus sequence typing (MLST) and the associations between sequence types and genotypes or virulence suggested that North American S. suis serotype 2 isolates are composed of multiple populations. This study investigated the population structure of S. suis serotype 2 isolates in China. We constructed a phylogenetic tree for S. suis serotype 2 isolates based on 16S rRNA gene typing and MLST, studied associations between clades and sources, analyzed the genotype distributions of virulence markers [muramidase-released protein (MRP), extracellular protein factor (EF), and suilysin (SLY)] in different clades, computed the selection pressures for these virulence marker genes, and verified the associations between clades and virulence. There were two primary clades (populations) in the phylogenetic tree of S. suis serotype 2. The two populations were associated with different tissue tropisms. The genotypic distributions and selection pressures of MRP, EF, and SLY were different between the two populations, which suggested that they had different evolutionary paths. The two populations also displayed differences in virulence in experimentally infected mice. The results provide insights into the population structure of S. suis serotype 2 isolates in China and suggest that S. suis serotype 2 clade 1 is an overlooked population that deserves further evaluation.
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Affiliation(s)
- Weifeng Zhu
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, PR China
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2
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Takamatsu D. [Diversity and virulence factors of Streptococcus suis ]. Nihon Saikingaku Zasshi 2011; 66:7-21. [PMID: 21498962 DOI: 10.3412/jsb.66.7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Daisuke Takamatsu
- Research Team for Bacterial/Parasitic Diseases, National Institute of Animal Health, National Agriculture and Food Research Organization, 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856
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Fittipaldi N, Fuller TE, Teel JF, Wilson TL, Wolfram TJ, Lowery DE, Gottschalk M. Serotype distribution and production of muramidase-released protein, extracellular factor and suilysin by field strains of Streptococcus suis isolated in the United States. Vet Microbiol 2009; 139:310-7. [DOI: 10.1016/j.vetmic.2009.06.024] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Revised: 06/04/2009] [Accepted: 06/12/2009] [Indexed: 11/17/2022]
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Surface-associated and secreted factors ofStreptococcus suisin epidemiology, pathogenesis and vaccine development. Anim Health Res Rev 2009; 10:65-83. [DOI: 10.1017/s146625230999003x] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
AbstractStreptococcus suisis an invasive porcine pathogen associated with meningitis, arthritis, bronchopneumonia and other diseases. The pathogen constitutes a major health problem in the swine industry worldwide. Furthermore,S. suisis an important zoonotic agent causing meningitis and other diseases in humans exposed to pigs or pork. Current knowledge on pathogenesis is limited, despite the enormous amount of data generated by ‘omics’ research. Accordingly, immunprophylaxis (in pigs) is hampered by lack of a cross-protective vaccine against virulent strains of this diverse species. This review focuses on bacterial factors, both surface-associated and secreted ones, which are considered to contribute toS. suisinteraction(s) with host factors and cells. Factors are presented with respect to (i) their identification and features, (ii) their distribution amongS. suisand (iii) their significance for virulence, immune response and vaccination. This review also shows the enormous progress made in research onS. suisover the last few years, and it emphasizes the numerous challenging questions remaining to be answered in the future.
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Sekizaki T, Nishiya H, Nakajima S, Nishizono M, Kawano M, Okura M, Takamatsu D, Nishino H, Ishiji T, Osawa R. Endocarditis in chickens caused by subclinical infection of Streptococcus gallolyticus subsp. gallolyticus. Avian Dis 2008; 52:183-6. [PMID: 18459321 DOI: 10.1637/8048-070307-case] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Streptococcus gallolyticus subsp. gallolyticus causes endocarditis in humans and acute septicemia in domestic birds. We describe here the infective endocarditis caused by the bacterium found among clinically healthy broilers at two abattoirs in Japan. The chickens were thought to be healthy because of the lack of clinical symptoms and normal levels of mortality before slaughtering. At the time of inspection, some chickens were condemned because of organ disorders characterized by vegetative valvular endocarditis as well as focal necrosis in heart, liver, and spleen. Streptococcus gallolyticus subsp. gallolyticus was isolated from the organs as a pure culture, indicating that the bacterium probably was the causative agent of the disorders. Amplified fragment length polymorphism analysis of the isolates collected at the abattoirs from chickens grown in nine different farms indicated that the isolates were different variants of the same clonal lineage and may have been derived from the same ancestor. These results suggest that S. gallolyticus subsp. gallolyticus causes infectious endocarditis in chickens and that healthy chickens may possess the bacterium in their normal flora as an opportunistic pathogen.
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Affiliation(s)
- Tsutomu Sekizaki
- National Institute of Animal Health, Tsukuba, Ibaraki 305-0856, Japan.
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Dumetz F, Duchaud E, Claverol S, Orieux N, Papillon S, Lapaillerie D, Le Hénaff M. Analysis of the Flavobacterium psychrophilum outer-membrane subproteome and identification of new antigenic targets for vaccine by immunomics. Microbiology (Reading) 2008; 154:1793-1801. [DOI: 10.1099/mic.0.2008/016600-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Fabien Dumetz
- Université Bordeaux 1, CNRS UMR 5805 EPOC, Place du Dr Peyneau, F-33120 Arcachon, France
| | - Eric Duchaud
- Unité de Virologie et Immunologie Moléculaires, INRA, Domaine de Vilvert, F-78352 Jouy-en-Josas Cedex, France
| | - Stéphane Claverol
- Plateforme Génomique Fonctionnelle, Université Victor Segalen Bordeaux 2, 146 Rue Léo Saignat, F-33076 Bordeaux Cedex, France
| | - Nicolas Orieux
- Université Bordeaux 1, CNRS UMR 5805 EPOC, Place du Dr Peyneau, F-33120 Arcachon, France
| | - Sandrine Papillon
- Université Bordeaux 1, CNRS UMR 5805 EPOC, Place du Dr Peyneau, F-33120 Arcachon, France
| | - Delphine Lapaillerie
- Plateforme Génomique Fonctionnelle, Université Victor Segalen Bordeaux 2, 146 Rue Léo Saignat, F-33076 Bordeaux Cedex, France
| | - Michel Le Hénaff
- Université Bordeaux 1, CNRS UMR 5805 EPOC, Place du Dr Peyneau, F-33120 Arcachon, France
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Li M, Wang C, Feng Y, Pan X, Cheng G, Wang J, Ge J, Zheng F, Cao M, Dong Y, Liu D, Wang J, Lin Y, Du H, Gao GF, Wang X, Hu F, Tang J. SalK/SalR, a two-component signal transduction system, is essential for full virulence of highly invasive Streptococcus suis serotype 2. PLoS One 2008; 3:e2080. [PMID: 18461172 PMCID: PMC2358977 DOI: 10.1371/journal.pone.0002080] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2007] [Accepted: 03/04/2008] [Indexed: 11/22/2022] Open
Abstract
Background Streptococcus suis serotype 2 (S. suis 2, SS2) has evolved into a highly infectious entity, which caused the two recent large-scale outbreaks of human SS2 epidemic in China, and is characterized by a toxic shock-like syndrome. However, the molecular pathogenesis of this new emerging pathogen is still poorly understood. Methodology/Principal Findings 89K is a newly predicted pathogenicity island (PAI) which is specific to Chinese epidemic strains isolated from these two SS2 outbreaks. Further bioinformatics analysis revealed a unique two-component signal transduction system (TCSTS) located in the candidate 89K PAI, which is orthologous to the SalK/SalR regulatory system of Streptococcus salivarius. Knockout of salKR eliminated the lethality of SS2 in experimental infection of piglets. Functional complementation of salKR into the isogenic mutant ΔsalKR restored its soaring pathogenicity. Colonization experiments showed that the ΔsalKR mutant could not colonize any susceptible tissue of piglets when administered alone. Bactericidal assays demonstrated that resistance of the mutant to polymorphonuclear leukocyte (PMN)-mediated killing was greatly decreased. Expression microarray analysis exhibited a transcription profile alteration of 26 various genes down-regulated in the ΔsalKR mutant. Conclusions/Significance These findings suggest that SalK/SalR is requisite for the full virulence of ethnic Chinese isolates of highly pathogenic SS2, thus providing experimental evidence for the validity of this bioinformatically predicted PAI.
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Affiliation(s)
- Ming Li
- Department of Microbiology, Third Military Medical University, Chongqing, China
- Department of Epidemiology, Research Institute for Medicine of Nanjing Command, Nanjing, China
| | - Changjun Wang
- Department of Epidemiology, Research Institute for Medicine of Nanjing Command, Nanjing, China
| | - Youjun Feng
- Center for Molecular Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- Graduate University, Chinese Academy of Sciences, Beijing, China
| | - Xiuzhen Pan
- Department of Epidemiology, Research Institute for Medicine of Nanjing Command, Nanjing, China
| | - Gong Cheng
- Department of Epidemiology, Research Institute for Medicine of Nanjing Command, Nanjing, China
| | - Jing Wang
- Department of Epidemiology, Research Institute for Medicine of Nanjing Command, Nanjing, China
| | - Junchao Ge
- Department of Epidemiology, Research Institute for Medicine of Nanjing Command, Nanjing, China
| | - Feng Zheng
- Department of Epidemiology, Research Institute for Medicine of Nanjing Command, Nanjing, China
| | - Min Cao
- Department of Epidemiology, Research Institute for Medicine of Nanjing Command, Nanjing, China
| | - Yaqing Dong
- Department of Epidemiology, Research Institute for Medicine of Nanjing Command, Nanjing, China
| | - Di Liu
- Center for Molecular Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Jufang Wang
- Provincial Key Laboratory of Biotechnology, School of Biosciences & Bioengineering, South China University of Technology, Guangzhou, China
| | - Ying Lin
- Provincial Key Laboratory of Biotechnology, School of Biosciences & Bioengineering, South China University of Technology, Guangzhou, China
| | - Hongli Du
- Provincial Key Laboratory of Biotechnology, School of Biosciences & Bioengineering, South China University of Technology, Guangzhou, China
| | - George F. Gao
- Center for Molecular Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Xiaoning Wang
- Provincial Key Laboratory of Biotechnology, School of Biosciences & Bioengineering, South China University of Technology, Guangzhou, China
- * E-mail: (XW); (FH); (JT)
| | - Fuquan Hu
- Department of Microbiology, Third Military Medical University, Chongqing, China
- * E-mail: (XW); (FH); (JT)
| | - Jiaqi Tang
- Department of Microbiology, Third Military Medical University, Chongqing, China
- Department of Epidemiology, Research Institute for Medicine of Nanjing Command, Nanjing, China
- * E-mail: (XW); (FH); (JT)
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Takamatsu D, Ide H, Osaki M, Sekizaki T. Identification of Facklamia sourekii from a Lactating Cow. J Vet Med Sci 2006; 68:1225-7. [PMID: 17146186 DOI: 10.1292/jvms.68.1225] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A gram-positive, catalase-negative, facultatively anaerobic coccus was isolated from a lactating cow with hematuria and urodynia in Japan. The isolate was identified by 16S rRNA gene sequence analysis as Facklamia sourekii. The biochemical and culture characteristics of the isolate were well consistent with those of F. sourekii type strain. Since all F. sourekii strains reported so far were isolated from human clinical specimens, this is the first reported case of F. sourekii isolated from veterinary clinical specimen.
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Jost BH, Billington SJ. Arcanobacterium pyogenes: molecular pathogenesis of an animal opportunist. Antonie van Leeuwenhoek 2005; 88:87-102. [PMID: 16096685 DOI: 10.1007/s10482-005-2316-5] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2004] [Accepted: 02/15/2005] [Indexed: 10/25/2022]
Abstract
Arcanobacterium pyogenes is a commensal and an opportunistic pathogen of economically important livestock, causing diseases as diverse as mastitis, liver abscessation and pneumonia. This organism possesses a number of virulence factors that contribute to its pathogenic potential. A. pyogenes expresses a cholesterol-dependent cytolysin, pyolysin, which is a haemolysin and is cytolytic for immune cells, including macrophages. Expression of pyolysin is required for virulence and this molecule is the most promising vaccine candidate identified to date. A. pyogenes also possesses a number of adherence mechanisms, including two neuraminidases, the action of which are required for full adhesion to epithelial cells, and several extracellular matrix-binding proteins, including a collagen-binding protein, which may be required for adhesion to collagen-rich tissue. A. pyogenes also expresses fimbriae, which are similar to the type 2 fimbriae of Actinomyces naeslundii, and forms biofilms. However, the role of these factors in the pathogenesis of A. pyogenes infections remains to be elucidated. A. pyogenes also invades and survives within epithelial cells and can survive within J774A.1 macrophages for up to 72 h, suggesting an important role for A. pyogenes interaction with host cells during pathogenesis. The two component regulatory system, PloSR, up-regulates pyolysin expression and biofilm formation but down-regulates expression of proteases, suggesting that it may act as a global regulator of A. pyogenes virulence. A. pyogenes is a versatile pathogen, with an arsenal of virulence determinants. However, most aspects of the pathogenesis of infection caused by this important opportunistic pathogen remain poorly characterized.
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Affiliation(s)
- B Helen Jost
- Department of Veterinary Science and Microbiology, University of Arizona, 1117 East Lowell Street, Tucson, AZ 85721, USA.
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Sekizaki T, Takamatsu D, Osaki M, Shimoji Y. Different foreign genes incidentally integrated into the same locus of the Streptococcus suis genome. J Bacteriol 2005; 187:872-83. [PMID: 15659665 PMCID: PMC545713 DOI: 10.1128/jb.187.3.872-883.2005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Some strains of Streptococcus suis possess a type II restriction-modification (RM) system, whose genes are thought to be inserted into the genome between purH and purD from a foreign source by illegitimate recombination. In this study, we characterized the purHD locus of the S. suis genomes of 28 serotype reference strains by DNA sequencing. Four strains contained the RM genes in the locus, as described before, whereas 11 strains possessed other genetic regions of seven classes. The genetic regions contained a single gene or multiple genes that were either unknown or similar to hypothetical genes of other bacteria. The mutually exclusive localization of the genetic regions with the atypical G+C contents indicated that these regions were also acquired from foreign sources. No transposable element or long-repeat sequence was found in the neighboring regions. An alignment of the nucleotide sequences, including the RM gene regions, suggested that the foreign regions were integrated by illegitimate recombination via short stretches of nucleotide identity. By using a thermosensitive suicide plasmid, the RM genes were experimentally introduced into an S. suis strain that did not contain any foreign genes in that locus. Integration of the plasmid into the S. suis genome did not occur in the purHD locus but occurred at various chromosomal loci, where there were 2 to 10 bp of nucleotide identity between the chromosome and the plasmid. These results suggest that various foreign genes described here were incidentally integrated into the same locus of the S. suis genome.
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Affiliation(s)
- Tsutomu Sekizaki
- Molecular Bacteriology Section, National Institute of Animal Health, 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856, Japan.
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11
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Harel J, Martinez G, Nassar A, Dezfulian H, Labrie SJ, Brousseau R, Moineau S, Gottschalk M. Identification of an inducible bacteriophage in a virulent strain of Streptococcus suis serotype 2. Infect Immun 2003; 71:6104-8. [PMID: 14500539 PMCID: PMC201037 DOI: 10.1128/iai.71.10.6104-6108.2003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus suis infection is considered to be a major problem in the swine industry worldwide. Most virulent Canadian isolates of S. suis serotype 2 do not produce the known virulence markers for this pathogen. PCR-based subtraction hybridization was adapted to isolate unique DNA sequences which were specific to virulent strains of S. suis isolated in Canada. Analysis of some subtracted DNA clones revealed significant homology with bacteriophages of gram-positive bacteria. An inducible phage (named Ss1) was observed in S. suis following the incubation of the virulent strain 89-999 with mitomycin C. Phage Ss1 has a long noncontractile tail and a small isometric nucleocapsid and is a member of the Siphoviridae family. Ss1 phage DNA appears to be present in most Canadian S. suis strains tested in this study, which were isolated from diseased pigs or had proven virulence in mouse or pig models. To our knowledge, this is the first report of the isolation of a phage in S. suis.
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Affiliation(s)
- J Harel
- Groupe de Recherche sur les Maladies Infectieuses du Porc, Faculté de Médecine Vétérinaire, Université de Montréal C.P. 5000, St-Hyacinthe, Quebec J2S 7C6, Canada .
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12
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Rudnick ST, Jost BH, Songer JG, Billington SJ. The gene encoding pyolysin, the pore-forming toxin of Arcanobacterium pyogenes, resides within a genomic islet flanked by essential genes. FEMS Microbiol Lett 2003; 225:241-7. [PMID: 12951248 DOI: 10.1016/s0378-1097(03)00527-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
The plo gene, encoding the Arcanobacterium pyogenes cholesterol-dependent cytolysin, pyolysin (PLO), was localized to a 2.7-kb genomic islet of reduced %G+C content and alternate codon usage frequency. This islet, conserved among isolates from diverse hosts and geographical locations, separated the housekeeping genes smc and ftsY, which are found adjacent in many prokaryotes. The ftsY and ffh genes, located downstream of the plo islet, encode components of the signal recognition particle. Mutational analysis suggested that these genes were essential for viability in A. pyogenes. The A. pyogenes ffh gene was unable to complement a conditional ffh mutant of Escherichia coli and its overexpression was toxic in E. coli. Mutagenesis of the islet-encoded orf121 did not affect plo expression, indicating that it may not be involved directly in the regulation of plo expression. Regardless, the presence of the plo gene as part of a genomic islet inserted between genes essential for normal growth may provide selective pressure for the retention of this important virulence factor.
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Affiliation(s)
- Stefani T Rudnick
- Department of Veterinary Science and Microbiology, The University of Arizona, 1117 East Lowell Street, Tucson, AZ 85721, USA
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13
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Vincent F, Charnock SJ, Verschueren KHG, Turkenburg JP, Scott DJ, Offen WA, Roberts S, Pell G, Gilbert HJ, Davies GJ, Brannigan JA. Multifunctional xylooligosaccharide/cephalosporin C deacetylase revealed by the hexameric structure of the Bacillus subtilis enzyme at 1.9A resolution. J Mol Biol 2003; 330:593-606. [PMID: 12842474 DOI: 10.1016/s0022-2836(03)00632-6] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Esterases and deacetylases active on carbohydrate ligands have been classified into 14 families based upon amino acid sequence similarities. Enzymes from carbohydrate esterase family seven (CE-7) are unusual in that they display activity towards both acetylated xylooligosaccharides and the antibiotic, cephalosporin C. The 1.9A structure of the multifunctional CE-7 esterase (hereinafter CAH) from Bacillus subtilis 168 reveals a classical alpha/beta hydrolase fold encased within a 32 hexamer. This is the first example of a hexameric alpha/beta hydrolase and is further evidence of the versatility of this particular fold, which is used in a wide variety of biological contexts. A narrow entrance tunnel leads to the centre of the molecule, where the six active-centre catalytic triads point towards the tunnel interior and thus are sequestered away from cytoplasmic contents. By analogy to self-compartmentalising proteases, the tunnel entrance may function to hinder access of large substrates to the poly-specific active centre. This would explain the observation that the enzyme is active on a variety of small, acetylated molecules. The structure of an active site mutant in complex with the reaction product, acetate, reveals details of the putative oxyanion binding site, and suggests that substrates bind predominantly through non-specific contacts with protein hydrophobic residues. Protein residues involved in catalysis are tethered by interactions with protein excursions from the canonical alpha/beta hydrolase fold. These excursions also mediate quaternary structure maintenance, so it would appear that catalytic competence is only achieved on protein multimerisation. We suggest that the acetyl xylan esterase (EC 3.1.1.72) and cephalosporin C deacetylase (EC 3.1.1.41) enzymes of the CE-7 family represent a single class of proteins with a multifunctional deacetylase activity against a range of small substrates.
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Affiliation(s)
- Florence Vincent
- Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5YW, UK
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Takamatsu D, Osaki M, Sekizaki T. Chloramphenicol resistance transposable element TnSs1 of Streptococcus suis, a transposon flanked by IS6-family elements. Plasmid 2003; 49:143-51. [PMID: 12726767 DOI: 10.1016/s0147-619x(02)00149-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A new transposon, designated TnSs1, which contains a chloramphenicol acetyltransferase gene flanked by direct repeats of an IS6-family element was found in a field isolate of Streptococcus suis. Polymerase chain reaction and hybridization analyses indicated that another field isolate carried the same transposon in a different location on the chromosome. A transposition assay done with a thermosensitive suicide vector showed that, among the seven TnSs1 mutants tested in this study, six formed a cointegrate between the S. suis genome and the vector with the generation of the third copy of the insertion sequence element, and one harbored one copy of TnSs1 on the chromosome as a result of a subsequent resolution step. On transposition, TnSs1 duplicated an 8-bp sequence at the target site.
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Affiliation(s)
- Daisuke Takamatsu
- Molecular Bacteriology Section, National Institute of Animal Health, 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856, Japan
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15
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Osaki M, Takamatsu D, Shimoji Y, Sekizaki T. Allelic variation in srtAs of Streptococcus suis strains. FEMS Microbiol Lett 2003; 219:195-201. [PMID: 12620620 DOI: 10.1016/s0378-1097(03)00058-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Streptococcus suis NCTC10234 possesses five srtA homologs: srtA encodes sortase, which anchors surface proteins with an LPXTG motif to the cell wall, while the functions of the other four homologs (the srtBCD cluster and srtE) remain unknown. The genetic organization of the srtA region was found to be conserved in the 59 S. suis strains examined in this study. Although the srtAs in three of these strains showed strong sequence divergence, their functions were verified to be overlapping by genetic complementation, indicating the functional conservation of srtAs during the evolution of these strains. These results indicate the importance of an srtA-mediated cell wall sorting system for displaying proteins on the surface of S. suis.
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Affiliation(s)
- Makoto Osaki
- Molecular Bacteriology Section, National Institute of Animal Health, 3-1-5 Kannondai, Tsukuba, 305-0856, Ibaraki, Japan
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Lun S, Perez-Casal J, Connor W, Willson PJ. Role of suilysin in pathogenesis of Streptococcus suis capsular serotype 2. Microb Pathog 2003; 34:27-37. [PMID: 12620382 DOI: 10.1016/s0882-4010(02)00192-4] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Three suilysin (SLY) knockout mutant strains of Streptococcus suis serotype 2 were generated by allelic replacement from one North American and two European wild type strains. The mutants were characterized by Southern blot, Western blot and phenotyping. In vitro bactericidal testing showed that both wild type and SLY mutants were resistant to bactericidal factors in whole pig blood. To demonstrate the role of SLY during S. suis infection, four animal trials were carried out using young pigs. Either high dose (4 x 10(6)CFU/ml/pig) or low dose (0.5 x 10(6)CFU/ml/pig) live cell aerosol was applied to the pharynx. In one trial, a low challenge dose of North American strain SX332 and its isogenic sly(-) mutant strain (SX932) resulted in acute disease in 3/5 of pigs exposed to the wild type strain, while 5/5 of pigs exposed to the mutant strain survived the trial. In the repeat trial, 1/8 of pigs in wild type group and 6/8 of pigs in mutant group developed disease. The high dose trial with 332/932 pair showed that 4/8 pigs challenged with wild type and 5/8 of pigs challenged with mutant strain developed disease respectively. The third low dose trial, using European strain 31533 and its isogenic sly(-) mutant strain SX911, showed that 1/8 of pigs challenged with the wild type strain and 4/8 of pigs challenged with the corresponding mutant strain developed disease. All the diseased pigs showed fever, clinical signs and developed septicemia. S. suis was isolated from tissue samples such as brain, submandibular lymph node, lung, spleen, liver, heart or joint. Serum antibody titer against cell surface proteins changed little while the antibody titer against SLY increased only in the wild type group after challenge. sly gene was cloned and expressed in E. coli. The recombinant SLY (rSLY) protein showed 800 hemolysin units per microg protein. In vitro study showed that rSLY triggered TNFalpha production by human monocytes and IL-6 production by pig pulmonary alveolar macrophages and monocytes. Thus, the results of this study suggest that SLY does not seem to be a critical virulence factor for S. suis serotype 2 respiratory infection, but by stimulating cytokine release it may play a role in innate immunity.
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Affiliation(s)
- Shichun Lun
- Veterinary Infectious Disease Organization, University of Saskatchewan, 120 Veterinary Road, Saskatoon, Saskatchewan, Canada S7N 5E3
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