Project description:We used a whole genome array containing 97.4 % of the annotated genes of Lactobacillus acidophilus NCFM, a probiotic culture that belongs to the lactic acid bacteria group, to identify genes that are differentially expressed under several stress conditions. Keywords: Stress response
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:Lactic acid bacteria (LAB) belong to an economically important group of Gram-positive microorganisms, whose main characteristic is the production of lactic acid by carbohydrates fermentation. Lactobacillus paraplantarum CRL 1905 is a LAB isolated from quinoa sourdoughs with biotechnological potential as a starter or probiotic. Inorganic phosphate (Pi) is an essential nutrient for most bacteria cell functions and it is involved in many regulatory processes. The aim of the project was to evaluate the influence of environmental Pi concentration in different physiological and molecular aspects of the CRL 1905 strain. Phenotypic and proteomic data provide new insights to understand the adaptations in several metabolic pathways that CRL 1905 experiments in response to differential Pi conditions.
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
2007-03-02 | GSE4325 | GEO
Project description:Sequencing lactic acid bacteria isolated from cheese
Project description:Pastick2009 - Genome-scale metabolic network
of Streptococcus thermophilus (iMP429)
This model is described in the article:
Genome-scale model of
Streptococcus thermophilus LMG18311 for metabolic comparison of
lactic acid bacteria.
Pastink MI, Teusink B, Hols P,
Visser S, de Vos WM, Hugenholtz J.
Appl. Environ. Microbiol. 2009 Jun;
75(11): 3627-3633
Abstract:
In this report, we describe the amino acid metabolism and
amino acid dependency of the dairy bacterium Streptococcus
thermophilus LMG18311 and compare them with those of two other
characterized lactic acid bacteria, Lactococcus lactis and
Lactobacillus plantarum. Through the construction of a
genome-scale metabolic model of S. thermophilus, the metabolic
differences between the three bacteria were visualized by
direct projection on a metabolic map. The comparative analysis
revealed the minimal amino acid auxotrophy (only histidine and
methionine or cysteine) of S. thermophilus LMG18311 and the
broad variety of volatiles produced from amino acids compared
to the other two bacteria. It also revealed the limited number
of pyruvate branches, forcing this strain to use the
homofermentative metabolism for growth optimization. In
addition, some industrially relevant features could be
identified in S. thermophilus, such as the unique pathway for
acetaldehyde (yogurt flavor) production and the absence of a
complete pentose phosphate pathway.
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Project description:Isolation and characterization of two recently isolated Novosphingobium oxfordensis sp. nov. and Novosphingobium mississippiensis sp. nov. strains from soil, with LCMS and genome-based investigation of their glycosphingolipid productions