Response of Lactococcus lactis to isoleucine starvation
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ABSTRACT:
ORGANISM(S): Lactococcus lactis
PROVIDER: GSE4872 | GEO | 2008/02/23
SECONDARY ACCESSION(S): PRJNA95935
REPOSITORIES: GEO
Similar Datasets
Project description:For the first time in Lactococcus lactis, amino acid starvation response was characterized. The natural imposition of isoleucine starvation, by its consumption during growth, associated to transcript profiling, allowed defining exhaustively this stress stimulon. It consisted of a general induction of nitrogen metabolism (amino acid biosynthesis and transport, proteolytic system and proteases), a strong repression of genes encoding major physiological activities (translation, transcription, carbon metabolism, purine and pyrimidine biosynthesis and fatty acid metabolism) and the induction of unexpected cross responses to acid, osmotic and oxidative stresses. Keywords: stress response, time course Isoleucine starvation was imposed by the consumption of this amino acid during the growth of Lactococcus lactis IL1403 on ILV0.1 medium (CDM with ten-fold reduced concentrations of isoleucine, leucine and valine) and under controlled conditions (30 °C, pH 6.6, nitrogen atmosphere). Cell samples were harvested in exponential phase and after 30 min, 1.7 h and 3.5 h of isoleucine starvation. Total RNA was extracted from these samples and radiolabelled cDNA were prepared and hybridized on nylon arrays. 2053 amplicons specific of Lactococcus lactis IL1403 genes were spotted twice on the array. The 4 time-points were analyzed simultaneously and 3 independent repetitions were performed.
2010-06-25 | E-GEOD-4872 | biostudies-arrayexpress
Project description:Amino acid assimilation and metabolism are crucial for bacterial growth and survival and this is particularly obvious for lactic acid bacteria (LAB) that are generally auxotroph for various amino acids. However, amino acid assimilation is poorly characterized and a complete description of the response during amino acid starvation is still lacking in LAB. In this context, the global response of the LAB model Lactococcus lactis was characterized during isoleucine starvation in batch culture. The stress was imposed by isoleucine natural consumption in an initially rich chemically defined medium. Dynamic analyses were performed both using transcriptomic and proteomic approaches. The response was found to occur gradually and could be divided into three major parts that were firstly deduced from transcriptomic analysis and generally corroborated by proteomic results: (i) a global repression of biogenic processes (transcription, translation, and carbon metabolism and transport), (ii) a specific response related to the limiting nutrient (numerous pathways belonging to carbon or nitrogen metabolism and leading to isoleucine supply were activated) and (iii) an additional response connected to oxidative stress (induction of aerobic metabolism, electron transport, thioredoxin metabolism and pyruvate dehydrogenase). The involvement of various regulatory mechanisms such as growth rate regulation, stringent response, CodY, GlnR, and CcpA regulations, was discussed on the basis of transcriptomic data comparisons. Above the full description of L. lactis isoleucine starvation response, this work additionally provided a complex but realistic outlook of the regulation network involved in isoleucine starvation. Such integrated and comparative approach will allow, by its implementation to other regulations and environmental conditions, the whole regulatory network of L. lactis or any other microorganism to be deciphered.
2011-09-22 | GSE12962 | GEO
Project description:Amino acid assimilation and metabolism are crucial for bacterial growth and survival and this is particularly obvious for lactic acid bacteria (LAB) that are generally auxotroph for various amino acids. However, amino acid assimilation is poorly characterized and a complete description of the response during amino acid starvation is still lacking in LAB. In this context, the global response of the LAB model Lactococcus lactis was characterized during isoleucine starvation in batch culture. The stress was imposed by isoleucine natural consumption in an initially rich chemically defined medium. Dynamic analyses were performed both using transcriptomic and proteomic approaches. The response was found to occur gradually and could be divided into three major parts that were firstly deduced from transcriptomic analysis and generally corroborated by proteomic results: (i) a global repression of biogenic processes (transcription, translation, and carbon metabolism and transport), (ii) a specific response related to the limiting nutrient (numerous pathways belonging to carbon or nitrogen metabolism and leading to isoleucine supply were activated) and (iii) an additional response connected to oxidative stress (induction of aerobic metabolism, electron transport, thioredoxin metabolism and pyruvate dehydrogenase). The involvement of various regulatory mechanisms such as growth rate regulation, stringent response, CodY, GlnR, and CcpA regulations, was discussed on the basis of transcriptomic data comparisons. Above the full description of L. lactis isoleucine starvation response, this work additionally provided a complex but realistic outlook of the regulation network involved in isoleucine starvation. Such integrated and comparative approach will allow, by its implementation to other regulations and environmental conditions, the whole regulatory network of L. lactis or any other microorganism to be deciphered. Batch cultivation of Lactococcus lactis IL1403 were carried out on a chemically defined medium and under controlled conditions (30 °C, pH 6.6, nitrogen atmosphere). Cell samples were harvested at steady state. Total RNA was extracted from these samples and radiolabelled cDNA were prepared and hybridized on nylon arrays. 1948 amplicons specific of Lactococcus lactis IL1403 genes were spotted twice on the array. Samples corresponding to various growth rates were analyzed simultaneously and 3 independent repetitions were performed.
2011-09-21 | E-GEOD-12962 | biostudies-arrayexpress
Project description:Our transcriptome data shows that ythA, which is a PspC family transcriptional regulator, obviously affects amino acid metabolism, pyrimidine biosynthesis and nisin immunity.
2018-03-14 | GSE101424 | GEO
Project description:Transcriptional regulation of branched-chain amino acid metabolism in Saccharomyces cerevisiae involves two key regulator proteins, Leu3p and Gcn4p. Leu3p is a pathway-specific regulator, known to regulate six genes involved in branched-chain amino acid metabolism and one gene in nitrogen assimilation. Gcn4p is a global regulator, involved in the general response to amino acid and purine starvation. To investigate the contribution of Leu3p in regulation of gene expression, a leu3D strain was compared to an isogenic reference strain using DNA-microarray analysis. This comparison was performed for both glucose-grown, ammonium-limited and ethanol-limited, ammonium-excess chemostat cultures. In ethanol-limited cultures, absence of Leu3p led to reduced transcript levels of six of the seven established Leu3p target genes, but did not affect key physiological parameters. In ammonium-limited cultures, absence of Leu3p caused a drastic decrease in storage carbohydrate content. mRNA levels of genes involved in storage carbohydrate metabolism were also found reduced. Under N-limited conditions, the leu3D genotype elicited an amino-acid starvation response, leading to increased transcript levels of many amino acid biosynthesis genes. By combining the transcriptome data with data from earlier studies that measured DNA binding of Leu3p both in vitro and in vivo, BAT1, GAT1 and OAC1 were identified as additional Leu3p-regulated genes. This study demonstrates that unravelling of transcriptional regulation networks should preferably include several cultivation conditions and requires a combination of experimental approaches.
2007-07-07 | E-GEOD-2076 | biostudies-arrayexpress
Project description:Our transcriptome data shows that comparative transcriptomics analysis was performed on L. lactis WH101 and L. lactis NZ9000 to investigated the response mechanisms of microbial cells during acid stress. Carbohydrate metabolism and sugar transporters were strengthened to provide more energy. Amino acids metabolism and transporters were regulated to maintain intracellular pHi homeostasis and generate ATP. Fatty acid metabolism was also regulated to enhance the acid tolerance of cells. Moreover, transcriptional regulators and stress response proteins were also found to be related to acid stress.
2021-07-11 | GSE116952 | GEO
Project description:Mice were put on either a control or low isoleucine diet and their liver transcriptomic expression was measured in both the fasting and fed state. This was to discover the impact of reducing a single branched chain amino acid on the metabolism of the liver.
2021-04-21 | GSE168588 | GEO
Project description:Transcriptional regulation of branched-chain amino acid metabolism in Saccharomyces cerevisiae involves two key regulator proteins, Leu3p and Gcn4p. Leu3p is a pathway-specific regulator, known to regulate six genes involved in branched-chain amino acid metabolism and one gene in nitrogen assimilation. Gcn4p is a global regulator, involved in the general response to amino acid and purine starvation. To investigate the contribution of Leu3p in regulation of gene expression, a leu3D strain was compared to an isogenic reference strain using DNA-microarray analysis. This comparison was performed for both glucose-grown, ammonium-limited and ethanol-limited, ammonium-excess chemostat cultures. In ethanol-limited cultures, absence of Leu3p led to reduced transcript levels of six of the seven established Leu3p target genes, but did not affect key physiological parameters. In ammonium-limited cultures, absence of Leu3p caused a drastic decrease in storage carbohydrate content. mRNA levels of genes involved in storage carbohydrate metabolism were also found reduced. Under N-limited conditions, the leu3D genotype elicited an amino-acid starvation response, leading to increased transcript levels of many amino acid biosynthesis genes. By combining the transcriptome data with data from earlier studies that measured DNA binding of Leu3p both in vitro and in vivo, BAT1, GAT1 and OAC1 were identified as additional Leu3p-regulated genes. This study demonstrates that unravelling of transcriptional regulation networks should preferably include several cultivation conditions and requires a combination of experimental approaches. Keywords: ordered
2004-12-17 | GSE2076 | GEO
Project description:CodY is a widely conserved global regulator, regulating nitrogen metabolism, virulence, and stress response in Gram-positive bacteria. Here, we performed ChIP-seq to define the CodY regulon in L. lactis, and found that CodY served either as an activator or as a repressor of hundreds of genes. The genes involved in amino acid biosynthesis and transport, cell wall synthesis, nisin synthesis and immunity, and several transcription regulators were identified regulated by CodY for the first time. Intriguingly, CodY could directly bind to the downstream of codY. This study gives new insights into the function of CodY controlling cell wall synthesis, nisin synthesis and immunity, as well as self-regulation in L. lactis.
2022-01-28 | GSE139902 | GEO