[Detection of quorum-sensing pathway and construction of luxS gene allelic exchange plasmid of Streptococcus mutans].
OBJECTIVE
To detect the AI-2 quorum-sensing pathway and construct the luxS g-ene allelic exchange plasmid of Streptococcus mutans.


METHODS
To detect AI-2 pathway in Streptococcus mutans, the Vibrio harveyi BB170 was used as reporter strain. The PCR fragments of the upstream and downstream regions of luxS and the Erythromycin resistance gene were amplified with the primers respectively, and these fragments were ligated into pUC19 vector with double endonuclease reaction sequentially, the ligated DNAs were transformed into Escherichia coli DH5alpha, then the reconstructed plasmids were isolated and identified by restricted endonuclease digestions.


RESULTS
Streptococcus mutans Ingbritt C could induce luminescence of BB170, suggesting the presence of AI-2 quorum sensing pathway in Streptococcus mutans, and such stimulatory activity was maximal at the mid-log growth phase. The recombinant plasmid pUCluxKO was digested by PstI-BamHI, and the digest product were 1000 bp and 5000 bp. When the pUCluxKO was digested by BamHI-KpnI, the digest product were 1500 bp and 4500 bp. While it was digested by KpnI-EcoRI, the digest product were 1000 bp and 5000 bp. All PCR product was in a single belt respectively.


CONCLUSIONS
The recombinant plasmid was cloned effectively and can be used in the construction of S.mutans luxS mutant.
Yu
Dan-ni
DN
Department of Stomatology, The Second Hospital of Tianjin Medical University, Tianjin 300211, China. danni2468@eyou.com
Han
Yu-zhi
YZ
Han
Fu-sheng
FS
Chen
Jie
J
D001426:Bacterial Proteins / Q000235:genetics*; D013437:Carbon-Sulfur Lyases / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D005822:Genetic Vectors; D006714:Homoserine / Q000235:genetics; D010957:Plasmids; D053038:Quorum Sensing / Q000235:genetics*; D013295:Streptococcus mutans / Q000235:genetics*
D001426:Bacterial Proteins; D006714:Homoserine; D013437:Carbon-Sulfur Lyases; C117753:LuxS protein, Bacteria