Najar F

References (2)

Title : Genome sequence of a nephritogenic and highly transformable M49 strain of Streptococcus pyogenes - McShan_2008_J.Bacteriol_190_7773
Author(s) : McShan WM , Ferretti JJ , Karasawa T , Suvorov AN , Lin S , Qin B , Jia H , Kenton S , Najar F , Wu H , Scott J , Roe BA , Savic DJ
Ref : Journal of Bacteriology , 190 :7773 , 2008
Abstract : The 1,815,783-bp genome of a serotype M49 strain of Streptococcus pyogenes (group A streptococcus [GAS]), strain NZ131, has been determined. This GAS strain (FCT type 3; emm pattern E), originally isolated from a case of acute post-streptococcal glomerulonephritis, is unusually competent for electrotransformation and has been used extensively as a model organism for both basic genetic and pathogenesis investigations. As with the previously sequenced S. pyogenes genomes, three unique prophages are a major source of genetic diversity. Two clustered regularly interspaced short palindromic repeat (CRISPR) regions were present in the genome, providing genetic information on previous prophage encounters. A unique cluster of genes was found in the pathogenicity island-like emm region that included a novel Nudix hydrolase, and, further, this cluster appears to be specific for serotype M49 and M82 strains. Nudix hydrolases eliminate potentially hazardous materials or prevent the unbalanced accumulation of normal metabolites; in bacteria, these enzymes may play a role in host cell invasion. Since M49 S. pyogenes strains have been known to be associated with skin infections, the Nudix hydrolase and its associated genes may have a role in facilitating survival in an environment that is more variable and unpredictable than the uniform warmth and moisture of the throat. The genome of NZ131 continues to shed light upon the evolutionary history of this human pathogen. Apparent horizontal transfer of genetic material has led to the existence of highly variable virulence-associated regions that are marked by multiple rearrangements and genetic diversification while other regions, even those associated with virulence, vary little between genomes. The genome regions that encode surface gene products that will interact with host targets or aid in immune avoidance are the ones that display the most sequence diversity. Thus, while natural selection favors stability in much of the genome, it favors diversity in these regions.
ESTHER : McShan_2008_J.Bacteriol_190_7773
PubMedSearch : McShan_2008_J.Bacteriol_190_7773
PubMedID: 18820018
Gene_locus related to this paper: strpy-ESTA , strpy-PEPXP , strpy-SPY1308

Title : Genome sequence of Streptococcus mutans UA159, a cariogenic dental pathogen - Ajdic_2002_Proc.Natl.Acad.Sci.U.S.A_99_14434
Author(s) : Ajdic D , McShan WM , McLaughlin RE , Savic G , Chang J , Carson MB , Primeaux C , Tian R , Kenton S , Jia H , Lin S , Qian Y , Li S , Zhu H , Najar F , Lai H , White J , Roe BA , Ferretti JJ
Ref : Proceedings of the National Academy of Sciences of the United States of America , 99 :14434 , 2002
Abstract : Streptococcus mutans is the leading cause of dental caries (tooth decay) worldwide and is considered to be the most cariogenic of all of the oral streptococci. The genome of S. mutans UA159, a serotype c strain, has been completely sequenced and is composed of 2,030,936 base pairs. It contains 1,963 ORFs, 63% of which have been assigned putative functions. The genome analysis provides further insight into how S. mutans has adapted to surviving the oral environment through resource acquisition, defense against host factors, and use of gene products that maintain its niche against microbial competitors. S. mutans metabolizes a wide variety of carbohydrates via nonoxidative pathways, and all of these pathways have been identified, along with the associated transport systems whose genes account for almost 15% of the genome. Virulence genes associated with extracellular adherent glucan production, adhesins, acid tolerance, proteases, and putative hemolysins have been identified. Strain UA159 is naturally competent and contains all of the genes essential for competence and quorum sensing. Mobile genetic elements in the form of IS elements and transposons are prominent in the genome and include a previously uncharacterized conjugative transposon and a composite transposon containing genes for the synthesis of antibiotics of the gramicidin/bacitracin family; however, no bacteriophage genomes are present.
ESTHER : Ajdic_2002_Proc.Natl.Acad.Sci.U.S.A_99_14434
PubMedSearch : Ajdic_2002_Proc.Natl.Acad.Sci.U.S.A_99_14434
PubMedID: 12397186
Gene_locus related to this paper: strmu-BACT , strmu-BGLB , strmu-GBPD , strmu-pepx , strmu-SMU.118C , strmu-SMU.178 , strmu-SMU.633 , strmu-SMU.643 , strmu-SMU.737 , strmu-SMU.1028 , strmu-SMU.1071C , strmu-SMU.1280C , strmu-SMU.1314 , strmu-SMU.1319C , strmu-SMU.1337C , strmu-SMU.1393C , strmu-SMU.1443C , strmu-SMU.1482C , strmu-SMU.1678