Novel insights into E. coli's hexuronate metabolism: KduI facilitates the conversion of galacturonate and glucuronate under osmotic stress conditions
| Autor: | Michael Blaut, Gunnar Loh, Monique Rothe, Carl Alpert |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2013 |
| Předmět: |
Osmosis
Osmotic shock Glucuronate Gene Expression lcsh:Medicine Biology medicine.disease_cause Biochemistry Microbiology Mice Model Organisms Glucuronic Acid Stress Physiological Microbial Physiology Molecular Cell Biology Dietary Carbohydrates Escherichia coli medicine Animals Hexuronate Bacterial Physiology Promoter Regions Genetic lcsh:Science Aldose-Ketose Isomerases Microbial Metabolism Cellular Stress Responses chemistry.chemical_classification Multidisciplinary Hexuronic Acids lcsh:R Wild type Bacteriology Gene Expression Regulation Bacterial Metabolism Enzymes Enzyme chemistry Carbohydrate Metabolism Prokaryotic Models lcsh:Q Research Article |
| Zdroj: | PLoS ONE, Vol 8, Iss 2, p e56906 (2013) PLoS ONE |
| ISSN: | 1932-6203 |
| Popis: | Using a gnotobiotic mouse model, we previously observed the upregulation of 2-deoxy-D-gluconate 3-dehydrogenase (KduD) in intestinal E. coli of mice fed a lactose-rich diet and the downregulation of this enzyme and of 5-keto 4-deoxyuronate isomerase (KduI) on a casein-rich diet. The present study aimed to define the role of the so far poorly characterized E. coli proteins KduD and KduI in vitro. Galacturonate and glucuronate induced kduD and kduI gene expression 3-fold and 7 to 11-fold, respectively, under aerobic conditions as well as 9 to 20-fold and 19 to 54-fold, respectively, under anaerobic conditions. KduI facilitated the breakdown of these hexuronates. In E. coli, galacturonate and glucuronate are normally degraded by UxaABC and UxuAB. However, osmotic stress represses the expression of the corresponding genes in an OxyR-dependent manner. When grown in the presence of galacturonate or glucuronate, kduID-deficient E. coli had a 30% to 80% lower maximal cell density and 1.5 to 2-fold longer doubling times under osmotic stress conditions than wild type E. coli. Growth on lactose promoted the intracellular formation of hexuronates, which possibly explain the induction of KduD on a lactose-rich diet. These results indicate a novel function of KduI and KduD in E. coli and demonstrate the crucial influence of osmotic stress on the gene expression of hexuronate degrading enzymes. |
| Databáze: | OpenAIRE |
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