Project description:Lactic acid bacteria (LAB) are of industrial importance in the production of fermented foods, among which sourdough-derived products. Despite their limited metabolic capacity LAB contribute considerably to important characteristics of fermented foods, among which extended shelf-life, microbial safety, improved texture, and enhanced organoleptic properties. Thanks to the considerable amount of LAB genomic information that became available during the last years, transcriptome, and by extension meta-transcriptome studies, are the exquisite research approaches to study whole ecosystem gene expression into more detail. In this study, microarray analyses were performed using RNA sampled during four 10-day spontaneous sourdough fermentations carried out in the laboratory, namely two wheat and two spelt fermentations with daily back-slopping. Hereto, the in-house developed functional gene LAB microarray was used, representing 406 genes that play a key role in sugar and nitrogen metabolism, functional metabolite production, stress responses and health and safety characteristics. The results reveal the activation of different key metabolic pathways, the ability to use different energy sources, and successful acid and oxidative stress responses. Also, a new algorithm was developed to compute a net expression profile for each of the represented genes, thereby exceeding the species level.
Project description:Lactic acid bacteria (LAB) are of industrial importance in the production of fermented foods, among which sourdough-derived products. Despite their limited metabolic capacity LAB contribute considerably to important characteristics of fermented foods, among which extended shelf-life, microbial safety, improved texture, and enhanced organoleptic properties. Thanks to the considerable amount of LAB genomic information that became available during the last years, transcriptome, and by extension meta-transcriptome studies, are the exquisite research approaches to study whole ecosystem gene expression into more detail. In this study, microarray analyses were performed using RNA sampled during four 10-day spontaneous sourdough fermentations carried out in the laboratory, namely two wheat and two spelt fermentations with daily back-slopping. Hereto, the in-house developed functional gene LAB microarray was used, representing 406 genes that play a key role in sugar and nitrogen metabolism, functional metabolite production, stress responses and health and safety characteristics. The results reveal the activation of different key metabolic pathways, the ability to use different energy sources, and successful acid and oxidative stress responses. Also, a new algorithm was developed to compute a net expression profile for each of the represented genes, thereby exceeding the species level.
Project description:Lactic acid bacteria (LAB) are of industrial importance in the production of fermented foods, among which sourdough-derived products. Despite their limited metabolic capacity LAB contribute considerably to important characteristics of fermented foods, among which extended shelf-life, microbial safety, improved texture, and enhanced organoleptic properties. Thanks to the considerable amount of LAB genomic information that became available during the last years, transcriptome, and by extension meta-transcriptome studies, are the exquisite research approaches to study whole ecosystem gene expression into more detail. In this study, microarray analyses were performed using RNA sampled during four 10-day spontaneous sourdough fermentations carried out in the laboratory, namely two wheat and two spelt fermentations with daily back-slopping. Hereto, the in-house developed functional gene LAB microarray was used, representing 406 genes that play a key role in sugar and nitrogen metabolism, functional metabolite production, stress responses and health and safety characteristics. The results reveal the activation of different key metabolic pathways, the ability to use different energy sources, and successful acid and oxidative stress responses. Also, a new algorithm was developed to compute a net expression profile for each of the represented genes, thereby exceeding the species level.
Project description:Lactic acid bacteria (LAB) are of industrial importance in the production of fermented foods, among which sourdough-derived products. Despite their limited metabolic capacity LAB contribute considerably to important characteristics of fermented foods, among which extended shelf-life, microbial safety, improved texture, and enhanced organoleptic properties. Thanks to the considerable amount of LAB genomic information that became available during the last years, transcriptome, and by extension meta-transcriptome studies, are the exquisite research approaches to study whole ecosystem gene expression into more detail. In this study, microarray analyses were performed using RNA sampled during four 10-day spontaneous sourdough fermentations carried out in the laboratory, namely two wheat and two spelt fermentations with daily back-slopping. Hereto, the in-house developed functional gene LAB microarray was used, representing 406 genes that play a key role in sugar and nitrogen metabolism, functional metabolite production, stress responses and health and safety characteristics. The results reveal the activation of different key metabolic pathways, the ability to use different energy sources, and successful acid and oxidative stress responses. Also, a new algorithm was developed to compute a net expression profile for each of the represented genes, thereby exceeding the species level.
Project description:Lactic acid bacteria (LAB) are of industrial importance in the production of fermented foods, among which sourdough-derived products. Despite their limited metabolic capacity LAB contribute considerably to important characteristics of fermented foods, among which extended shelf-life, microbial safety, improved texture, and enhanced organoleptic properties. Thanks to the considerable amount of LAB genomic information that became available during the last years, transcriptome, and by extension meta-transcriptome studies, are the exquisite research approaches to study whole ecosystem gene expression into more detail. In this study, microarray analyses were performed using RNA sampled during four 10-day spontaneous sourdough fermentations carried out in the laboratory, namely two wheat and two spelt fermentations with daily back-slopping. Hereto, the in-house developed functional gene LAB microarray was used, representing 406 genes that play a key role in sugar and nitrogen metabolism, functional metabolite production, stress responses and health and safety characteristics. The results reveal the activation of different key metabolic pathways, the ability to use different energy sources, and successful acid and oxidative stress responses. Also, a new algorithm was developed to compute a net expression profile for each of the represented genes, thereby exceeding the species level. The labeled aRNA of the sourdough fermentation samples was hybridized using a loop design, i.e. subsequent samples (e.g. 27 h and 51 h, 51 h and 75 h etc.) were hybridized together on the microarray and the loop was closed by hybridizing the last sample with the first.
Project description:Lactic acid bacteria (LAB) are of industrial importance in the production of fermented foods, among which sourdough-derived products. Despite their limited metabolic capacity LAB contribute considerably to important characteristics of fermented foods, among which extended shelf-life, microbial safety, improved texture, and enhanced organoleptic properties. Thanks to the considerable amount of LAB genomic information that became available during the last years, transcriptome, and by extension meta-transcriptome studies, are the exquisite research approaches to study whole ecosystem gene expression into more detail. In this study, microarray analyses were performed using RNA sampled during four 10-day spontaneous sourdough fermentations carried out in the laboratory, namely two wheat and two spelt fermentations with daily back-slopping. Hereto, the in-house developed functional gene LAB microarray was used, representing 406 genes that play a key role in sugar and nitrogen metabolism, functional metabolite production, stress responses and health and safety characteristics. The results reveal the activation of different key metabolic pathways, the ability to use different energy sources, and successful acid and oxidative stress responses. Also, a new algorithm was developed to compute a net expression profile for each of the represented genes, thereby exceeding the species level. The labeled aRNA of the sourdough fermentation samples was hybridized using a loop design, i.e. subsequent samples (e.g. 27 h and 51 h, 51 h and 75 h etc.) were hybridized together on the microarray and the loop was closed by hybridizing the last sample with the first.
Project description:Background: Lactobacillus plantarum is found in a variety of fermented foods and as such, consumed for centuries. Some strains are natural inhabitants of the human gastro-intestinal tract and like other Lactobacillus species, L. plantarum has been extensively studied for its immunomodulatory properties and its putative health-promoting effects (probiotic). Being the first line of host defense intestinal epithelial cells (IEC) are key players in the recognition and initiation of responses to gut microorganisms. Results: Using high-density oligonucleotide microarrays we examined the gene expression profiles of differentiated Caco-2 cells exposed to various doses of L. plantarum. In addition, the effects were correlated to monolayer permeability studies and measurement of lactic acid production. A transcriptional dose-dependent IEC response to L. plantarum was found. Incubation of Caco-2 with a low bacterial dose induced a specific response, not due to cytotoxicity or production of lactic acid, including modulation of cell cycle and cell signaling functions. Exposure of Caco-2 cells to larger amounts of bacteria, accompanied by the production of lactic acid and glucose depletion, provoked increased permeability and supposed non-specific defense responses. Conclusions: These results suggest that IEC are able to sense and react to the presence of gut bacteria. This study provides the first description of global transcriptional response of human IEC to a commensal lactic acid bacterium, and it shows the importance of choosing physiological bacterial doses to prevent the observation of non-specific host reactions. Keywords: host-microbe interaction; dose response; transcriptional analysis
Project description:Background: Lactobacillus plantarum is found in a variety of fermented foods and as such, consumed for centuries. Some strains are natural inhabitants of the human gastro-intestinal tract and like other Lactobacillus species, L. plantarum has been extensively studied for its immunomodulatory properties and its putative health-promoting effects (probiotic). Being the first line of host defense intestinal epithelial cells (IEC) are key players in the recognition and initiation of responses to gut microorganisms. Results: Using high-density oligonucleotide microarrays we examined the gene expression profiles of differentiated Caco-2 cells exposed to various doses of L. plantarum. In addition, the effects were correlated to monolayer permeability studies and measurement of lactic acid production. A transcriptional dose-dependent IEC response to L. plantarum was found. Incubation of Caco-2 with a low bacterial dose induced a specific response, not due to cytotoxicity or production of lactic acid, including modulation of cell cycle and cell signaling functions. Exposure of Caco-2 cells to larger amounts of bacteria, accompanied by the production of lactic acid and glucose depletion, provoked increased permeability and supposed non-specific defense responses. Conclusions: These results suggest that IEC are able to sense and react to the presence of gut bacteria. This study provides the first description of global transcriptional response of human IEC to a commensal lactic acid bacterium, and it shows the importance of choosing physiological bacterial doses to prevent the observation of non-specific host reactions. Caco-2 cells were exposed for 10h to Lactobacillus. Fourteen samples are analyzed: 4 control Caco-2, 4 Caco-2 exposed to a low dose (10) of Lactobacillus, 4 Caco-2 exposed to a medium dose (100) of Lactobacillus, 2 Caco-2 exposed to a high dose (1000) of Lactobacillus. All 14 RNA samples are labeled with Cy5 and hybridized to a common reference (undifferentiated Caco-2, untreated) RNA labeled with Cy3
Project description:Nowadays, Western diets and lifestyle lead to an increasing occurrence of chronic gut inflammation, that represents an emerging health concern with still a lack of successful therapies. Fermented foods, and their associated Lactic Acid Bacteria, have recently regained popularity for their probiotic potential including the maintenance of gut homeostasis by modulating the immune and inflammatory response. Our study aims to investigate the cross-talk between the food-borne strain Lactiplantibacillus plantarum C9O4 and intestinal epithelial cells in an in vitro inflammation model. Cytokines profile shows the ability of C9O4 to significantly reduce levels of IL-2, IL-5, IL-6, and IFN-γ. Proteomic functional analysis reveals an active host-microbe interaction that highlights an immunoregulatory role of C9O4, able to revert both the detrimental effects of IFN-γ through the JAK/STAT pathway and the apoptosis process in inflamed cells. These results suggest a promising therapeutic role of fermented food-associated microbes for the management of gastrointestinal inflammatory diseases.