Project description:Lactobacillus casei is remarkably adaptive to diverse habitats. To understand the evolution and adaptation of Lb. casei strains isolated from different environments, the gene content of 22 Lb. casei strains isolated from various habitats (cheeses, n=8; plant materials, n=8; and human sources, n=6) were examined by comparative genome hybridization with an Lb. casei ATCC 334-based microarray.
Project description:Lactobacillus casei is remarkably adaptive to diverse habitats. To understand the evolution and adaptation of Lb. casei strains isolated from different environments, the gene content of 22 Lb. casei strains isolated from various habitats (cheeses, n=8; plant materials, n=8; and human sources, n=6) were examined by comparative genome hybridization with an Lb. casei ATCC 334-based microarray. Comparative genome hybridization was performed against an Affymetrix custom microarray designed to include 2,661 (97%) chromosomal and 17 (85%) plasmid CDSs predicted to occur in Lb. casei ATCC 334, as well as all predicted CDSs in the draft Lb. helveticus CNRZ 32 genome. CDSs that were not included in the microarray design were all transposase-encoding genes.
Project description:Lactobacillus casei Zhang is a probiotic bacterium isolated from koumiss in Inner Mongolia of China that has been commercially used as a starter in the manufacture of dairy products. To study the gene expression profiles of L. casei Zhang during growth in milk, a whole-genome microarray was used. Compared to L. casei Zhang grown to late logarithmic phase in milk, 61 genes were significantly up-regulated (>5 fold) in stationary phase, whereas 26 genes were down-regulated. Collectively, these data showed that the majority of the identified genes was involved in carbohydrate metabolism and energy production, followed by genes involved in nucleotide metabolism, inorganic ion transport, amino acid transport and metabolism, chaperone, etc. This study demonstrates the fundamental effects of cultural conditions on the transcriptome of L. casei Zhang. Moreover, it improves the understanding of the growth and survival mechanism of the bacterium during the late stage of milk fermentation.
Project description:The response to bile of Lactobacillus casei BL23 was investigated. Lactobacillus casei BL23 was grown in MRS medium at 37C without shaking until O.D. 595 nm. reached 0.5. The cultures were then two fold diluted with prewarmed MRS medium (control) or MRS supplemented with 0.2% bovine bile (treatment) and incubation continued for 45 min. Cells were then harvested and total RNA purified.
