Exploring the distribution of citrinin biosynthesis related genes among Monascus species.

Citrinin, a hepato-nephrotoxic compound to humans, can be produced by the food fermentation microorganisms Monascus spp. In this study, we investigated the distribution of mycotoxin citrinin biosynthesis genes in 18 Monascus strains. The results show that the acyl-transferase and keto-synthase domains of the pksCT gene encoding citrinin polyketide synthase were found in Monascus purpureus, Monascus kaoliang, and Monascus sanguineus.

Mutation of a key residue in the type II secretion system ATPase uncouples ATP hydrolysis from protein translocation.

Membrane-associated ATPase constitutes an essential element common to all secretion machineries in Gram-negative bacteria. How ATP hydrolysis by these ATPases is coupled to secretion process remains unclear. Here we identified R286 as a key residue in the type II secretion system (T2SS) ATPase XpsE of Xanthomonas campestris that plays a pivotal role in coupling ATP hydrolysis to protein translocation.