Overexpression of luxS Cannot Increase Autoinducer-2 Production, Only Affect the Growth and Biofilm Formation in Streptococcus suis

Table 1

Characteristics of bacterial strains, plasmids, and primers used in this study.

Strain, plasmid, and primer	Relevant characteristics^a or sequence (5′-3′)^b	Source of references
Strains
HA9801	Virulent strain of SS2 isolated from dead pig	Collected in our laboratory
ΔluxS	Mutation in luxS gene of HA9801; Cm^r	[8]
CΔluxS	Complemented strain of ΔluxS; Spc^r; Cm^r	[8]
luxS+	Overexpressing strain of luxS; Spc^r	In this study
E. coli DH5a	Cloning host for maintaining the recombinant plasmids	Invitrogen
V. harveyi BB170	BB120 luxN::Tn5 (sensor 1^−, sensor 2^+) V. harveyi	[11]
V. harveyi BB120	Wild type V. harveyi	[11]
Plasmid
pMD18-T vector	Clone vector	Takara
pSET2 vector	E. coli-S. suis shuttle vector; Spc^r	[8]
Primers
Cup	CCGG AATTCACCTCGGTTCCTTGTCTG	In this study
Cdown	GCGGGATCCGCTTCTTGTTCTGCGTTT; amplifies the structural gene of the luxS gene, including its own promoter (922bp)	In this study
LuxS-F	CAAGTCATCAAGTCGAGTTTGGAAG	In this study
LuxS-R	TCTTTAGCTGAATGAAGGCTGTGG; real-time for luxS	In this study
Pfs-F	CGTTCTTGTTCAGTCAGGTATCGG	In this study
Pfs-R	GATGGCAATACCTTCAGCAACAG; real-time for pfs	In this study
16S rRNA-F	GTTGCGAACGGGTGAGTAA	In this study
16S rRNA-R	TCTCAGGTCGGCTATGTATCG; real-time for 16S rRNA	In this study

aAp^r, ampicillin resistant; Spc^r, spectinomycin resistant; Cm^r, chloramphenicol resistant; ^bUnderlined nucleotides are restriction sites of the enzymes.