Project description:L. helveticus is used to modulate cheese flavor and as a starter organism in certain cheese varieties. Our group has compiled a draft (4x) sequence for the 2.4 Mb genome of an industrial strain L. helveticus CNRZ32. The primary aim was to investigate expression of 168 completely sequenced genes during growth in milk and MRS medium using microarrays. Oligonucleotide probes against each of the completely sequenced genes were compiled on maskless photolithography-based DNA microarrays. Additionally, the entire draft genome sequence was used to produce tiled microarrays where the non-interrupted sequence contigs were covered by consecutive 24-mer probes. Keywords: growth conditions response
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: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. L. casei Zhang was grown in milk for 14h (late logarithmic phase) or 18h (stationary phase). 2 biological replicates each.
Project description:Growth of L. cremoris NCDO712 was not altered when manganese is omitted from its defined medium. This study was conducted in order to compare protein requirements of Lactococcus cremoris NCDO712 to grow in the presence or absence of manganese in defined medium (1% lactose). The majority of protein adaptation involves upregulation of Mn transporters and to a lesser extent various NADH-dependent proteins. Such adaptation is highly relevant for starter culture in dairy fermentation where manganese is limited and NADH homeostasis determines the formation of volatiles during long-term incubation e.g. cheese ripening.
Project description:To study the characteristics of proteins in Chinese Chixiang-flavor Baijiu fermentation, a label-free quantitative proteomics approach was established to identify proteins in Jiuqu starter and fermented grains.
Project description:Propionibacterium freudenreichii is used as a ripening culture in Swiss cheese manufacture. It produces flavor compounds over the whole ripening period. During cheese ripening, P. freudenreichii is exposed to a temperature downshift, especially when cheeses are transferred from warm temperature (about 24°C) to cold temperature (about 4°C). The cold adaptation of the type strain was studied previously. The aim of this study was to investigate the adaptation of 6 other P. freudenreichii strains at cold temperature by means of a global gene expression profile. The temporal transcriptomic response of 6 P. freudenreichii strains was analyzed at 2 times of growth, during growth at 30°C then after 3 days 4°C, in the constant presence of lactate as the main carbon source.