Project description:Bifidobacteria have been described as a key component of the human gut microbiota, and recently significant efforts have been made to investigate their genome contents and assess the genetic variability at inter- and intra-species level. In the current work we investigated genome diversity among representatives of bifidobacterial species, i.e., Bifidobacterium adolescentis. These analyses were performed with comparative genomic hybridization (CGH) experiments and they revealed the existence of a strictly conserved set of 685 gene families. Furthermore, CGH analyses showed that genetic regions of diversity included mobile elements and putative genomic life-style adaptation islands, such as loci that encode pili and capsular polysaccharides, and genes involved in carbohydrate metabolism. CGH analysis was performed with microarrays that were based on the genome sequences of B. adolescentis ATCC15703 (NC_008618) . A total of 39,249 probes of 35 bp in length were designed using OligoArray 2.1 software. Oligos were synthesized in triplicate on a 2 × 40-k CombiMatrix array (CombiMatrix, Mulkiteo, USA). Replicates were distributed on the chip at random, non-adjacent positions. A set of 74 negative control probes designed on phage and plant sequences was also included on the chip. Seventeen micrograms of purified genomic DNA was labeled with Cy5-ULS using the Kreatech ULS array CGH Labeling kit (Kreatech Diagnostics) according to the supplier’s instructions. Hybridization of labeled test DNA to these microarrays was performed according to CombiMatrix protocols.
