A<i>dam</i>mutant of<i>Yersinia pestis</i>is attenuated and induces protection against plague

Robinson, Victoria; Oyston, Petra C. F.; Titball, Richard W.

doi:10.1016/j.femsle.2005.09.001

Cited by 60 publications

(64 citation statements)

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“…In addition to genetic factors, it should also be noted that epigenetic factors may also play important roles in fitness and pathogenesis. The influence of DNA adenine methylation on virulence has been demonstrated for various pathogens, including Vibrio cholerae (45), Salmonella enterica (46), Yersinia pestis (47), and Mycobacterium tuberculosis (48). The methylation of DNA at specific sites may exert influences through the regulation of chromosome replication, transcriptional regulation, and mismatch repair in response to various environmental stimuli (49,50).…”

Section: Discussionmentioning

confidence: 99%

Genomic Characterization of a Pattern D Streptococcus pyogenes emm53 Isolate Reveals a Genetic Rationale for Invasive Skin Tropicity

et al. 2016

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The genome of an invasive skin-tropic strain (AP53) of serotype M53 group A Streptococcus pyogenes (GAS) is composed of a circular chromosome of 1,860,554 bp and carries genetic markers for infection at skin locales, viz., emm gene family pattern D and FCT type 3. Through genome-scale comparisons of AP53 with other GAS genomes, we identified 596 candidate single-nucleotide polymorphisms (SNPs) that reveal a potential genetic basis for skin tropism. The genome of AP53 differed by ϳ30 point mutations from a noninvasive pattern D serotype M53 strain (Alab49), 4 of which are located in virulence genes. One pseudogene, yielding an inactive sensor kinase (CovS ؊ ) of the two-component transcriptional regulator CovRS, a major determinant for invasiveness, severely attenuated the expression of the secreted cysteine protease SpeB and enhanced the expression of the hyaluronic acid capsule compared to the isogenic noninvasive AP53/CovS ؉ strain. The collagen-binding protein transcript sclB differed in the number of 5=-pentanucleotide repeats in the signal peptides of AP53 and Alab49 (9 versus 15), translating into different lengths of their signal peptides, which nonetheless maintained a full-length translatable coding frame. Furthermore, GAS strain AP53 acquired two phages that are absent in Alab49. One such phage (⌽AP53.2) contains the known virulence factor superantigen exotoxin gene tandem speK-slaA. Overall, we conclude that this bacterium has evolved in multiple ways, including mutational variations of regulatory genes, short-tandem-repeat polymorphisms, large-scale genomic alterations, and acquisition of phages, all of which may be involved in shaping the adaptation of GAS in specific infectious environments and contribute to its enhanced virulence. IMPORTANCEInfectious strains of S. pyogenes (GAS) are classified by their serotypes, relating to the surface M protein, the emm-like subfamily pattern, and their tropicity toward the nasopharynx and/or skin. It is generally agreed that M proteins from pattern D strains, which also directly bind human host plasminogen, are skin tropic. We have sequenced and characterized the genome of an invasive pattern D GAS strain (AP53) in comparison to a very similar strain (Alab49) that is noninvasive and developed a genomic rationale as to possible reasons for the skin tropicity of these two strains and the greater invasiveness of AP53. G roup A Streptococcus pyogenes (GAS) is a beta-hemolytic, Gram-positive, human-pathogenic bacterium that infects multiple epithelial surfaces and, in some cases, is able to invade deeper soft tissue and cause severe disease (1). An estimated 700 million cases of GAS infection occur worldwide per year (2), ranging from benign treatable clinical conditions, e.g., pharyngitis and impetigo, to more invasive and potentially lethal infections, including necrotizing fasciitis (NF), streptococcal toxic shock syndrome (STSS), acute rheumatic fever (ARF), and acute glomerulonephritis (AGN) (3, 4). The wide range of infectious niches and broad varianc...

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Section: Discussionmentioning

confidence: 99%

Genomic Characterization of a Pattern D Streptococcus pyogenes emm53 Isolate Reveals a Genetic Rationale for Invasive Skin Tropicity

et al. 2016

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“…Moreover, GATC methylation plays a role in the virulence of diverse pathogens, e.g. Salmonella enterica serovar Typhimurium, Vibrio cholerae, Yersinia pestis, and Yersinia pseudotuberculosis (Heithoff et al, 1999;Julio et al, 2001;Robinson et al, 2005). It has also been shown that the dam gene is essential for the viability of A. hydrophila SSU and that M. AhySSUDam is involved in A. hydrophila pathogenesis (Erova et al, 2006a(Erova et al, , b, 2012.…”

Section: Functional Analysis Of the Dna Methylation Enzymes Of Farm81mentioning

confidence: 99%

Two novel temperate bacteriophages co-existing in Aeromonas sp. ARM81 – characterization of their genomes, proteomes and DNA methyltransferases

Dziewit

Radlińska

2016

Journal of General Virology

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Aeromonas species are causative agents of a wide spectrum of diseases in animals and humans. Although these bacteria are commonly found in various environments, little is known about their phages. Thus far, only one temperate Aeromonas phage has been characterized. Whole-genome sequencing of an Aeromonas sp. strain ARM81 revealed the presence of two prophage clusters. One of them is integrated into the chromosome and the other was maintained as an extrachromosomal, linear plasmid-like prophage encoding a protelomerase. Both prophages were artificially and spontaneously inducible. We separately isolated both phages and compared their genomes with other known viruses. The novel phages show no similarity to the previously characterized Aeromonas phages and might represent new evolutionary lineages of viruses infecting Aeromonadaceae. Apart from the comparative genomic analyses of these phages, complemented with their structural and molecular characterization, a functional analysis of four DNA methyltransferases encoded by these viruses was conducted. One of the investigated N6-adenine-modifying enzymes shares sequence specificity with a Dam-like methyltransferase of its bacterial host, while another one is non-specific, as it catalyzes adenine methylation in various sequence contexts. The presented results shed new light on the diversity of Aeromonas temperate phages.

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“…Transcription of the genes is controlled by the temperature and activity of the secretion apparatus (Cornelis, 2002;Viboud & Bliska, 2005). Anisimov, 2002a, b, Anisimov et al, 2004Brubaker, 1991;Oyston et al, 2000;Perry & Fetherston, 1997;Robinson et al, 2005;Sing et al, 2002;Sodhi et al, 2004 Infective doses of 10 bacteria or less are sufficient to cause lethal infection in naïve rodents and primates via the intradermal, subcutaneous and intravenous routes (Anisimov et al, 2004;Brubaker, 1991;Perry & Fetherston, 1997). LD 50 values in the case of the respiratory and oral routes of infection increase to 10 2 -10 4 c.f.u.…”

Section: Pathogenesis and Virulence Factorsmentioning

confidence: 99%