Affiliation:
1. Institute for Infectious Diseases, University of Bern, Bern, Switzerland
2. University Hospital, Bern, Switzerland
Abstract
ABSTRACT
In
Streptococcus pneumoniae
expression of pyruvate oxidase (SpxB) peaks during the early growth phase, coincident with the time of natural competence. This study investigated whether SpxB influences parameters of competence, such as spontaneous transformation frequency, expression of competence genes, and DNA release. Knockout of the
spxB
gene in strain D39 abolished spontaneous transformation (compared to a frequency of 6.3 × 10
−6
in the parent strain [
P
< 0.01]). It also reduced expression levels of
comC
and
recA
as well as DNA release from bacterial cells significantly during the early growth phase, coincident with the time of spontaneous competence in the parent strain. In the
spxB
mutant, supplementation with competence-stimulating peptide 1 (CSP-1) restored transformation (rate, 1.8 × 10
−2
). This speaks against the role of SpxB as a necessary source of energy for competence. Neither supplementation with CSP-1 nor supplementation with the SpxB products H
2
O
2
and acetate altered DNA release. Supplementation of the parent strain with catalase did not reduce DNA release significantly. In conclusion, the pneumococcal
spxB
gene influences competence; however, the mechanism remains elusive.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Cited by
31 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献