5 U of DNA Polymerase, and 4 μl of the bacterial DNA template in a final volume of 50 μl. The thermocycle program consisted of the following time and temperature profile: 95°C for 15 min; 30 cycles of 95°C

for 60 s, 56°C for 30 s, 72°C for 30 s; and 72°C for 8 min. A volume of 15-20 μl of PCR samples was used for DGGE analysis, which was performed by using the D-Code Universal Mutation System Apparatus (Bio-Rad, Los Angeles, CA), as previously described [52]. Briefly, the sequence-specific separation of the PCR fragments Tariquidar was obtained in 8% (w/v) polyacrylamide gels, containing a 30% to 50% gradient of urea and formamide. Electrophoresis was started at a voltage of 250 V for 5 minutes and continued at constant voltage of 90 V and temperature of 60°C for 16 h. Following electrophoresis, the gel was silver stained [53] and scanned using a Molecular Imager Gel Doc XR System (Bio-Rad). DGGE gel images were analyzed using the FPQuest Software Version 4.5 (Bio-Rad). In order to compensate for gel-to-gel differences and external distortion to electrophoresis, the DGGE patterns were aligned and normalized using an external reference ladder, containing PCR amplicons from pure cultures of intestinal bacterial species. A cluster analysis of the DGGE patterns was performed using the FPQuest Software. The similarity in

the profiles was calculated on the basis of the Pearson correlation coefficient with the www.selleckchem.com/products/AZD8931.html Ward clustering algorithm. Development of L. helveticus species-specific primers By using 16S and 16S-23S rRNA sequences obtained from the DDBJ and EMBL databases, multiple alignments of sequences related to L. helveticus and reference organisms were constructed with the program Clustal W http://​www.​ebi.​ac.​uk/​Tools/​clustalw2. Potential target sites for specific detection of the species L. helveticus were identified and the following primers

were designed: F_Hel (5′-GTGCCATCCTAAGAGATTAGGA-3′) and R_Hel (5′-TATCTCTACTCTCCATCACTTC-3′). A Blast search http://​www.​ncbi.​nlm.​nih.​gov/​BLAST was carried out to test the virtual specificity of the primers. Validation of specificity was performed by PCR experiments against different species of Lactobacillus (L. acidophilus, PTK6 L. casei, L. plantarum, L. bulgaricus, L. reuteri, L. gasseri, L. johnsonii) and other intestinal selleck kinase inhibitor genera (Bifidobacterium, Streptococcus, Escherichia). The primers were synthesized by M-Medical (Milan, Italy) and optimal annealing temperature was established by gradient PCR. Real-time quantitative PCR Quantitative PCR was performed in a LightCycler instrument (Roche, Mannheim, Germany) and SYBR Green I fluorophore was used to correlate the amount of PCR product with the fluorescence signal. The following genus- and species-specific primers sets, targeted to 16S or 16S-23S rRNA sequences, were used: Bif164/Bif662 (Bifidobacterium [54]); Lac1/Lab0677r (Lactobacillus [55, 56]); BiLON1/BiLON2 (B. longum [29]); F_Hel/R_Hel (L. helveticus [this work]).