1% SDS and final pH 8. 200 μl elution buffer was added to each tube containing a piece of gel. The gel was then crushed in smaller pieces using a pipet tip. Tubes were

incubated overnight at 37°C with shaking. Following centrifugation in a microcentrifuge at room temperature for 10 minutes at 10,000 rpm, supernatant was removed and transferred to a clean 2.0 ml tube. Ethanol (500 μl) was added to precipitate the DNA and tubes were AZD8186 order placed at −20°C overnight. DNA was pelleted at 13,000 rpm for 10 minutes. Supernatant was removed and DNA solubilized in 100 μl of 10 mM Tris pH 8 and 15 μl of 5 M sodium chloride was added. DNA was then precipitated a second time with 2 volumes of ethanol and kept overnight at −20°C. Precipitated DNA was recovered by centrifugation in a microcentrifuge at 13,000 rpm for 15 minutes, supernatant was removed and RSL3 mw DNA was Barasertib ic50 dried. Final resuspension of DNA was done with 10 μl of 10 mM Tris pH 8. The DNA fragments were cloned into the BamHI site in pUC18. Prior to ligation, BamHI-digested pUC18 was dephosphorylated using shrimp alkaline phosphatase

(Fermentas Inc.) and the reaction stopped by heat-inactivation. Ligation was performed overnight at room temperature with T4 DNA ligase (Fermentas Inc.). Transformation of calcium chloride competent E. coli DH5α cells was done following standard procedure [54]. Over 40 transformant colonies were streak-purified from each experiment. A selection of them were then used for plasmid preparation and tested for the crotamiton presence of an insert using restriction digest with EcoRI and PstI. Fragments cloned in pUC18 were sequenced using primers M13F provided by the sequencing facility (University of Waterloo) or LB61 (Table 3). Sequences were first analyzed by searching for Sau3AI (Bsp143I) restriction sites to determine the limits of each fragment. Each fragment sequence was then searched against S. meliloti Rm1021 genomic sequence using the BLAST tool from Toulouse annotation website [55]. Genes in closest proximity to identified sequences and potentially regulated by ChvI were searched against STRING 8.1 databases (June 28, 2009)

for functional relations [23]. The search was directed from the Toulouse annotation website. Reporter gene fusion strains Transcriptional fusion strains were obtained by transduction from the reporter gene fusion library strains made by Cowie et al. [20]. SmFL strains were used to prepare transduction lysates to transfer the gene fusions from the original S. meliloti RmP110 background into the Rm1021 background. Selection of transductants was done on LB with gentamicin (60 μg ml-1). The same lysates were also used to transduce gene fusions into SmUW38 (pKD001) with selection on LB gentamicin (60 μg ml-1) and neomycin (200 μg ml-1). Four transductants per transduction experiment were picked and streaked on LB gentamicin and neomycin.