Effects of recombinase A deficiency on biofilm formation by Streptococcus mutans.
OBJECTIVE
Recombinase A (RecA) is essential for the transformation of both plasmid and chromosomal DNA in Streptococcus pneumoniae and is considered to be related to the SOS-response in Streptococcus mutans.


METHODS
In the present study, a RecA-deficient mutant strain (RAD) was constructed by insertional inactivation of the recA gene encoding the RecA protein in strain MT8148 of S. mutans, after which the biological functions of acid tolerance and biofilm formation were investigated.


RESULTS
RAD showed reduced acid tolerance and produced lower density biofilm compared with the wild-type strain. In addition, confocal microscopic observation indicated that the biofilm produced by RAD was composed of cells with significantly lower viability compared with that produced by strain MT8148.


CONCLUSIONS
These results suggest that RecA has a relationship with biofilm formation.
Inagaki
S
S
Department of Pediatric Dentistry, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan.
Matsumoto-Nakano
M
M
Fujita
K
K
Nagayama
K
K
Funao
J
J
Ooshima
T
T
D001426:Bacterial Proteins / Q000502:physiology*; D018441:Biofilms / Q000254:growth & development*; D002470:Cell Survival; D015964:Gene Expression Regulation, Bacterial; D055786:Gene Knockout Techniques; D006863:Hydrogen-Ion Concentration; D018613:Microscopy, Confocal; D011938:Rec A Recombinases / Q000235:genetics / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013295:Streptococcus mutans / Q000201:enzymology* / Q000235:genetics; D013312:Stress, Physiological / Q000235:genetics
D001426:Bacterial Proteins; D011938:Rec A Recombinases