The LysR Transcription Factor, HexS, Is Required for Glucose Inhibition of Prodigiosin Production by .

Generation of many useful microbe-derived secondary metabolites, including the red pigment prodigiosin of the bacterium , is inhibited by glucose. In a previous report, a genetic approach was used to determine that glucose dehydrogenase activity (GDH) is required for inhibiting prodigiosin production and transcription of the prodigiosin biosynthetic operon (). However, the transcription factor(s) that regulate this process were not characterized.

Mutation of crp mediates Serratia marcescens serralysin and global secreted protein production.

The bacterial species Serratia marcescens secretes both beneficial and cytotoxic proteins. Here we report that a crp mutant exhibited elevated secreted protease activity. A genetic screen revealed that the gene coding for the metalloprotease serralysin was necessary for the elevated proteolysis, and this was confirmed by western blot analysis.

Serratia marcescens quinoprotein glucose dehydrogenase activity mediates medium acidification and inhibition of prodigiosin production by glucose.

Serratia marcescens is a model organism for the study of secondary metabolites. The biologically active pigment prodigiosin (2-methyl-3-pentyl-6-methoxyprodiginine), like many other secondary metabolites, is inhibited by growth in glucose-rich medium. Whereas previous studies indicated that this inhibitory effect was pH dependent and did not require cyclic AMP (cAMP), there is no information on the genes involved in mediating this phenomenon.

Cyclic AMP negatively regulates prodigiosin production by Serratia marcescens.

Many Serratia marcescens strains produce the red pigment prodigiosin, which has antimicrobial and anti-tumor properties. Previous reports suggest that cyclic AMP (cAMP) is a positive regulator of prodigiosin production. Supporting this model, the addition of glucose to growth medium inhibited pigment production in rich and minimal media.