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Expression of the hemolysin trait in a proteolytic transconjugant of Streptococcus faecalis

I A Casas1, E Marquez, L N Zimmerman

  • 1Depart. de Biologia, Facultad de Ciencias Veterinarias, Universidad del Zulia, Maracaibo, Venezuela.

Biochimie
|February 1, 1988
PubMed

Insights

Streptococcus faecalis strain 31H-1 exhibits hemolytic activity when its protease function is inhibited. This suggests the 38.5 Mdal plasmid conjugation is mediated by sex pheromones.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Genetics

Background:

  • Streptococcus faecalis strain 31H-1 is a transconjugant derived from strain 31B.
  • It contains a 38.5 Mdal plasmid encoding hemolysin, originally from strain X14.
  • The strain's proteolytic activity interferes with hemolytic expression in broth.

Purpose of the Study:

  • To investigate the conditions affecting hemolytic activity in Streptococcus faecalis strain 31H-1.
  • To elucidate the mechanism of conjugation for the 38.5 Mdal plasmid.

Main Methods:

  • Assessing hemolytic activity under varying conditions, including protease inhibition with EDTA.
  • Analyzing the effect of erythromycin and proteinase K on conjugation.

Main Results:

  • Hemolytic activity was detectable when proteolytic activity was inhibited by 10(-4) M EDTA.
  • Erythromycin and proteinase K influenced conjugation, indicating a specific mediation system.

Conclusions:

  • Proteolytic activity masks hemolysin expression in Streptococcus faecalis strain 31H-1.
  • Conjugation of the 38.5 Mdal plasmid in S. faecalis strain X14 is likely sex-pheromone mediated.

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