Back to Search
Start Over
Investigation of the adaptation of Lactococcus lactis to isoleucine starvation integrating dynamic transcriptome and proteome information.
- Source :
-
Microbial cell factories [Microb Cell Fact] 2011 Aug 30; Vol. 10 Suppl 1, pp. S18. Date of Electronic Publication: 2011 Aug 30. - Publication Year :
- 2011
-
Abstract
- Background: Amino acid assimilation is crucial for bacteria and this is particularly true for Lactic Acid Bacteria (LAB) that are generally auxotroph for amino acids. The global response of the LAB model Lactococcus lactis ssp. lactis was characterized during progressive isoleucine starvation in batch culture using a chemically defined medium in which isoleucine concentration was fixed so as to become the sole limiting nutriment. Dynamic analyses were performed using transcriptomic and proteomic approaches and the results were analysed conjointly with fermentation kinetic data.<br />Results: The response was first deduced from transcriptomic analysis and corroborated by proteomic results. It occurred progressively and could be divided into three major mechanisms: (i) a global down-regulation of processes linked to bacterial growth and catabolism (transcription, translation, carbon metabolism and transport, pyrimidine and fatty acid metabolism), (ii) a specific positive response related to the limiting nutrient (activation of pathways of carbon or nitrogen metabolism and leading to isoleucine supply) and (iii) an unexpected oxidative stress response (positive regulation of aerobic metabolism, electron transport, thioredoxin metabolism and pyruvate dehydrogenase). The involvement of various regulatory mechanisms during this adaptation was analysed on the basis of transcriptomic data comparisons. The global regulator CodY seemed specifically dedicated to the regulation of isoleucine supply. Other regulations were massively related to growth rate and stringent response.<br />Conclusion: This integrative biology approach provided an overview of the metabolic pathways involved during isoleucine starvation and their regulations. It has extended significantly the physiological understanding of the metabolism of L. lactis ssp. lactis. The approach can be generalised to other conditions and will contribute significantly to the identification of the biological processes involved in complex regulatory networks of micro-organisms.
- Subjects :
- Amino Acids genetics
Gene Expression Profiling
Gene Expression Regulation, Bacterial
Isoleucine genetics
Lactococcus lactis genetics
Lactococcus lactis growth & development
Lactococcus lactis metabolism
Proteomics
Transcriptome
Amino Acids metabolism
Isoleucine metabolism
Lactococcus lactis physiology
Subjects
Details
- Language :
- English
- ISSN :
- 1475-2859
- Volume :
- 10 Suppl 1
- Database :
- MEDLINE
- Journal :
- Microbial cell factories
- Publication Type :
- Academic Journal
- Accession number :
- 21995707
- Full Text :
- https://doi.org/10.1186/1475-2859-10-S1-S18