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Competence regulation by oxygen in Streptococcus pneumoniae : involvement of ciaRH and comCDE
Author(s) -
Echenique José R.,
ChapuyRegaud Sabine,
Trombe MarieClaude
Publication year - 2000
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.2000.01891.x
Subject(s) - biology , streptococcus pneumoniae , competence (human resources) , microbiology and biotechnology , psychology , social psychology , antibiotics
Anaerobic aerotolerant Streptococcus pneumoniae modulates its genetic transformability and its virulence in response to the oxygen concentration. The activity of a single protein encoded by nox and showing NADH oxidase activity is involved in these adaptive responses to O 2 . Northern blot analysis of wild‐type cultures grown under aerobic and microaerobic conditions indicated transcriptional control of comCDE by O 2 . An O 2 ‐independent mutant strain carrying the gain‐of‐function mutation comE38KE was isolated and its analysis showed that ComE is a key point in competence stimulation by O 2 . Plasmid insertion mutations in ciaRH revealed that this two component signal‐transducing system negatively regulates comCDE transcription. The level of comCDE transcripts appears as a major control point in competence regulation by O 2 and also by growth phase and cell density.