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: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.
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 aim of this study was to investigate the adaptation of P. freudenreichii at cold temperature by means of the first global gene expression profile for this species. The temporal transcriptomic response of P. freudenreichii was analyzed at five times of growth, during growth at 30°C then for 9 days at 4°C, in the constant presence of lactate as the main carbon source. P. freudenreichii response was also investigated by RT-qPCR for 30 genes, by proteomics and metabolomics (main metabolites quantified in culture supernatant). Microarray analysis revealed that 565 genes (25% of the protein-coding sequences of P. freudenreichii genome) were differentially expressed during transition from warm to cold temperature (P < 0.05 and |fold change| > 1). Most of the down-expressed genes were involved in cell machinery (cell division, protein turnover, translation, transcription and DNA replication). During incubation at cold temperature, P. freudenreichii accumulated carbon supplies by up-regulating genes involved in lactate, alanine and serine conversion to pyruvate, in gluconeogenesis and in glycogen synthesis. Interestingly, some genes involved in the formation of important flavor compounds of cheese, coding for an extracellular lipolytic esterases and enzymes of the pathways of formation of branched-chain compounds, were not significantly affected by cold. In conclusion, P. freudenreichii is metabolically active at cold temperature and induces pathways to maintain its long-term viability, which could explain its contribution to cheese ripening even at low temperature.
Project description:We report here the complete genome sequence of Lacticaseibacillus paracasei NSMJ15, isolated from makgeolli (a traditional Korean fermented liquor) and shown to have potentially probiotic characteristics. The genome consisted of a 2.79-Mbp chromosome contig and four plasmids having a total of 2,947 genes, including 2,690 coding sequences.
