Autolysis of Neisseria gonorrhoeae

2001

Molecular Microbiology

176

292

Neisseria gonorrhoeae (the gonococcus) is the causative agent of the sexually transmitted disease gonorrhoea. Most gonococcal infections remain localized to the genital tract but, in a small proportion of untreated cases, the bacterium becomes systemic to produce the serious complication of disseminated gonococcal infection (DGI). We have identified a large region of chromosomal DNA in N. gonorrhoeae that is not found in a subset of gonococcal isolates (a genetic island), in the closely related pathogen, Neisseria meningitidis or in commensal Neisseria that do not usually cause disease. Certain versions of the island carry a serum resistance locus and a gene for the production of a cytotoxin; these versions of the island are found preferentially in DGI isolates. All versions of the genetic island encode homologues of F factor conjugation proteins, suggesting that, like some other pathogenicity islands, this region encodes a conjugation‐like secretion system. Consistent with this hypothesis, a wild‐type strain released large amounts of DNA into the medium during exponential growth without cell lysis, whereas an isogenic strain mutated in a peptidoglycan hydrolase gene (atlA) was drastically reduced in its ability to donate DNA for transformation during growth. This genetic island constitutes the first major discriminating factor between the gonococcus and the other Neisseria and carries genes for providing DNA for genetic transformation.

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A variable genetic island specific for Neisseria gonorrhoeae is involved in providing DNA for natural transformation and is found more often in disseminated infection isolates

Dillard¹,

2001

Molecular Microbiology

176

292

“…To test the latter possibility, live and dead Opa-expressing Gc were compared in their ability to elicit PMN ROS production. Liquid-grown OpaB + FA1090 Gc were heated to 56°C for 30 min, a condition that inhibits autolysis (Hebeler and Young, 1975;Elmros et al, 1976) and results in a complete loss of bacterial viability (data not shown). The heat-killed Gc elicited 12-fold more total ROS production in PMNs than their live counterparts (Fig.…”

Section: Nonviable Gc Stimulate Ros Production In Pmnsmentioning

confidence: 99%

Neisseria gonorrhoeaesuppresses the oxidative burst of human polymorphonuclear leukocytes

Criss

2008

Cellular Microbiology

127

“…Several biochemical activities have been described that could contribute to PG hydrolysis and autolysis in gonococci. Hebeler and Young characterized a pH-dependent N-acetylmuramyl-L-alanine amidase activity and found that this was the major cell-lysing activity in vitro (Hebeler and Young, 1975;. Chapman and Perkins (1983) described an endopeptidase activity in gonococcal extracts capable of cleaving the peptide cross-links present in PG (Chapman and Perkins, 1983).…”

Section: Introductionmentioning

confidence: 99%

A peptidoglycan hydrolase similar to bacteriophage endolysins acts as an autolysin in Neisseria gonorrhoeae

Dillard

1997

Molecular Microbiology

SummaryWe have identified a gene encoding an autolysin (atlA) from Neisseria gonorrhoeae. The deduced amino acid sequence of AtlA shows significant similarity to the peptidoglycan degrading transglycosylases (endolysins) of bacteriophages lambda and P2, suggesting that the encoded protein also functions in peptidoglycan hydrolysis. An atlA mutant was identical to the wild-type strain in exponential growth rate, but demonstrated reduced lysis and peptidoglycan turnover in the stationary phase of growth. When transferred into a buffer solution, at a pH non-permissive for other gonococcal autolysins, an autolytic activity was detectable in the wild-type strain that was not present in the mutant. The most dramatic phenotype of the mutant occurred after extended time in stationary phase. After approximately 16 h in stationary phase, both strains underwent an apparent replication event, after which the wild-type strain died rapidly whereas the atlA mutant survived considerably longer. Even after both the wild-type and mutant cells were dead, many of the mutant cells maintained intact morphology, whereas the wild-type cells were lysed. These results suggest that AtlA is a peptidoglycan transglycosylase related to bacteriophage endolysins and acts as an autolysin in the stationary phase.