Project description:Genomic rearrangement, often driven by insertion sequence (IS) elements, is one of the major processes in the evolution of prokaryotes. Sequence analysis of 16S rRNA of Lactobacillus helveticus, an organism that evolved in a dairy environment and Lactobacillus acidiophilus an organism that evolved associated with the gastrointestinal tract (GIT) demonstrated 98.4% identity suggesting that they divergently evolved from a common ancestor. Moreover, complete genome sequence analysis of both organisms has demonstrated a remarkable degree of gene synteny (75% homologous genes) despite the presence of an exceptionally high number and diversity of IS elements in the Lb. helveticus genome. Array based comparative genomic hybridization (aCGH) performed on nine strains of Lb. helveticus revealed sixteen clusters of open reading frames (ORFs) flanked by IS elements. Four of these ORFs are associated with restriction/modification which may have played a role in accelerated evolution of strains in a commercially intensive ecosystem undoubtedly challenged through successive phage attack. Furthermore, analysis of the IS-flanked clusters demonstrated that the most frequently encountered IS were also those most abundant in the genome (IS1201, ISL2, ISLhe1, ISLhe2, ISLhe65 and ISLhe63). These findings contribute to the overall viewpoint on a versatile character of IS elements and the role they may play in bacterial genome plasticity.
Project description:The presence of tagatose in Lactobacillus rhamnosus strain GG caused induction of a large number of genes associated with carbohydrate metabolism including the phosphotransferase system. In addition, these results indicate the tagatose enhanced the growth of Lactobacillus casei 01 and Lactobacillus rhamnosus strain GG and their probiotic activities by activating tagatose-associated PTS networks.
Project description:The presence of tagatose in Lactobacillus rhamnosus strain GG caused induction of a large number of genes associated with carbohydrate metabolism including the phosphotransferase system. In addition, these results indicate the tagatose enhanced the growth of Lactobacillus casei 01 and Lactobacillus rhamnosus strain GG and their probiotic activities by activating tagatose-associated PTS networks. Two-condition experiment, Lactobacillus rhamnosus GG with glucose vs. Lactobacillus rhamnosus GG with tagatose. For preparing the total RNA, Lactobacillus rhamnosus GG cells were grown at 37M-BM-0C in prebiotic minimum medium supplemented with 2% glucose or tagatose for 24 h.
