Insertional inactivation of the major autolysin gene of Streptococcus pneumoniae. Academic Article uri icon

Overview

abstract

  • The lytA gene encoding the major pneumococcal autolysin (N-acetylmuramoyl-L-alanine amidase) was inactivated by inserting the 2-kilobase MspI fragment of pE194 containing the staphylococcal ermC gene. Stable autolysis-deficient (Lyt-) mutants and their isogenic Lyt+ parents were used in experiments designed to test possible physiological functions of the amidase. No autolysis could be induced in the mutants grown at 37 degrees C by deoxycholate, by incubation in stationary phase, or by treatment with penicillin. On the other hand, the Lyt- mutants exhibited normal growth rates and yields and normal adaptive responses during shifts from one growth temperature or nutritional condition to another. There was no evidence for impeded cell separation (chain formation). Colonies of Lyt- insertional mutants produced normal hemolytic zones on blood agar; they showed normal (high) levels of competence for genetic transformation. Lyt- mutants were also able to produce type 3 and 6 capsular polysaccharides, and such strains showed the same degree of virulence in mice as did the isogenic Lyt+ parent. The physiological function(s) of the amidase remains a puzzle.

publication date

  • December 1, 1988

Research

keywords

  • Amidohydrolases
  • DNA Transposable Elements
  • Genes
  • Genes, Bacterial
  • N-Acetylmuramoyl-L-alanine Amidase
  • Streptococcus pneumoniae

Identity

PubMed Central ID

  • PMC211707

Scopus Document Identifier

  • 0024205130

PubMed ID

  • 2903859

Additional Document Info

volume

  • 170

issue

  • 12