Project description:Mechanisms allowing P. freudenreichii adaptation to digestive stresses have been only studied in vitro so far. Our aim was therefore to study P. freudenreichii metabolic adaptation to intra-colonic conditions in situ. We maintained a pure culture of P. freudenreichii CIRM-BIA1, contained in a dialysis bag, within the colon of vigilant piglets during 24 hours. A transcriptomic analysis identified the metabolic pathways induced by this environment, in comparison with control propionibacteria maintained in spent culture medium.
Project description:Mechanisms allowing P. freudenreichii adaptation to digestive stresses have been only studied in vitro so far. Our aim was therefore to study P. freudenreichii metabolic adaptation to intra-colonic conditions in situ. We maintained a pure culture of P. freudenreichii CIRM-BIA1, contained in a dialysis bag, within the colon of vigilant piglets during 24 hours. A transcriptomic analysis identified the metabolic pathways induced by this environment, in comparison with control propionibacteria maintained in spent culture medium. 12 cutures in a dialysis bag in the colon of piglets during 24H compared to 12 cultures propionibacteria maintained in spent culture medium
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 an important starter culture used in the manufacture of Swiss-type cheeses. We have generated the complete genome sequence of a Propionibacterium freudenreichii ssp. shermanii strain JS at the Institute of Biotechnology, University of Helsinki, by using a combination of pyrosequencing with GS FLX and GS FLX Titanium series reagents (Roche) and SOLiD 4 (Life Technologies), ABI 3130xl Genetic Analyzer (Life Technologies), and PacBio RS II (Pacific Biosciences) instruments. Initial genome annotation was carried out using RAST, and additional functional annotation information for each CDS was obtained from BLANNOTATOR, CDD, and KAAS. Accession number for genome sequence is PRJEB12148. This submission is for the transcriptome analysis of Propionibakcterium freudenreichii in cheese ripening under warm and cold conditions. The RNA reads were mapped to the reference genome PRJEB12148.
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:This study was performed to monitor ethylene glycol metabolism by Propionibacterium freudenreichii and to elucidate the metabolic pathway involved.
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 24M-BM-0C) to cold temperature (about 4M-BM-0C). 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 30M-BM-0C then after 3 days 4M-BM-0C, in the constant presence of lactate as the main carbon source. Six strains were used: CIRM-BIA9, CIRM-BIA118, CIRM-BIA122, CIRM-BIA123, CIRM-BIA472, CIRM-BIA482. Gene expression was measured in the middle of exponential growth phase at 30M-BM-0C (20h, OD650 M-bM-^IM-^H 0.5), and after 3days of incubation at 4M-BM-0C. Three independent biological experiments were performed for each strain and at each time, and were labelled A, B, C. Five technical repetitions were performed using the RNA of 3J_122B, 3J_123A, 3J_472C, 20H_9A and 20H_482C samples. These technical repetitions were labelled 3J_122Bii, 3J_123Aii, 3J_472Cii, 20H_9Aii and 20H_482Cii respectively. The transcriptomic data for 20H_122A and 3J_123C samples were abberant and were thus not considered for further analysis.
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. Gene expression was measured in the middle of exponential growth phase at 30°C (20 h, OD650 ≈ 0.5), at the end of exponential growth phase (40 h, OD650 ≈ 2), and after 3, 6 and 9 days of incubation at 4°C. Three independent biological experiments were performed at each time (20h, 40h, 3, 6 and 9 days) and labelled A, B, C. One technical repetition was performed using the RNA of the 20HA sample ; This technical repetition was labelled 20HAbis.