Expression of the genes of the alkane degradation pathway encoded in the Pseudomonas putida OCT plasmid are subject to negative and dominant global control depending on the carbon source used and on the physiological status of the cell. We investigated the signals responsible for this control in chemostat cultures under conditions of nutrient or oxygen limitation. Our results show that this glo...

Cystic fibrosis (CF) patients are highly susceptible to chronic pulmonary disease caused by mucoid Pseudomonas aeruginosa strains that overproduce the exopolysaccharide alginate. We showed here that a mutation in zwf, encoding glucose-6-phosphate dehydrogenase (G6PDH), leads to a approximately 90% reduction in alginate production in the mucoid, CF isolate, P. aeruginosa FRD1. The main regulator...

BACKGROUND Industrial fermentation typically uses complex nitrogen substrates which consist of mixture of amino acids. The uptake of amino acids is known to be mediated by several amino acid transporters with certain preferences. However, models to predict this preferential uptake are not available. We present the stoichiometry for the utilization of amino acids as a sole carbon and nitrogen su...

The effect of glucose and other soluble sugars (xylose, fructose, maltose, cellobiose and lactose) in the production of amylases by Aspergillus tamarii was studied in solid state fermentation (SSF). Wheat bran solid state cultures were resistant to catabolite repression even at high concentration of glucose (10%). Results show the potential of solid state systems to overcome the adverse effects...

A catabolite repression gene (cat) which alters the sensitivity of Escherichia coli to catabolite repression has been mapped by transduction and shown to be located between the pyrC and purB genes. When the cat-1 mutation was studied in a number of genetic backgrounds, the results showed that this mutation affects the synthesis of more than one catabolic enzyme but does not completely eliminate...

In many bacteria glucose is the preferred carbon source and represses the utilization of secondary substrates. In Bacillus subtilis, this carbon catabolite repression (CCR) is achieved by the global transcription regulator CcpA, whose activity is triggered by the availability of its phosphorylated cofactors, HPr(Ser46-P) and Crh(Ser46-P). Phosphorylation of these proteins is catalyzed by the me...

Five mutations in ccpA of Bacillus megaterium with impaired functions were analysed for carbon catabolite repression. The phenotypes support the hypothesis that CcpA assumes a PurR/LacI fold. The completely inactive mutants CcpA119GE and CcpA326am cause alterations which are incompatible with that fold. A mutation with reduced activity, CcpA81GE, affects a site that would be partially surface e...