Proteome response of Monascus pilosus during rice starch limitation with suppression of monascorubramine production

Quantitative Proteomics Analysis by Sequential Window Acquisition of All Theoretical Mass Spectra-Mass Spectrometry Reveals Inhibition Mechanism of Pigments and Citrinin Production of Monascus Response to High Ammonium Chloride Concentration

Various Monascus bioactive metabolites used as food or food additives in Asia for centuries are subjected to constant physical and chemical changes and different Monascus genus. With the aim to identify enzymes that participate in or indirectly regulate the pigments and citrinin biosynthesis pathways of Monascus purpureus cultured under high ammonium chloride, the changes of the proteome profile were examined using sequential window acquisition of all theoretical mass spectra-mass spectrometry-based quantitative proteomics approach in combination with bioinformatics analysis. A total of 292 proteins were confidently detected and quantified in each sample, including 163 that increased and 129 that decreased (t-tests, p ≤ 0.05). Pathway analysis indicated that high ammonium chloride in the present study accelerates the carbon substrate utilization and promotes the activity of key enzymes in glycolysis and β-oxidation of fatty acid catabolism to generate sufficient acetyl-CoA. However, the synthesis of the monascus pigments and citrinin was not enhanced because of inhibition of the polyketide synthase activity. All results demonstrated that the cause of initiation of pigments and citrinin synthesis is mainly due to the apparent inhibition of acyl and acetyl transfer by some acyltransferase and acetyltransferase, likely malony-CoA:ACP transacylase.

Enhanced hypolipidemic effect and safety of red mold dioscorea cultured in deep ocean water

Red mold dioscorea (RMD) produced by Monascus sp. was proven to be a hypolipidemic functional food. Deep ocean water (DOW), that is, water obtained from over 200 m deep in the ocean, was found to promote the growth of fungus via its mineral richness. On the basis of the advantages, this study used 650 m DOW as the culture water to culture Monascus purpuresus NTU 568 and produce the DOW-RMD. The goal of this study is to compare the difference between DOW-RMD and reverse osmosis water-cultured RMD (ROW-RMD) on the hypolipidemic effect. Hyperlipidemic hamsters were fed a high-cholesterol diet and administered various doses of DOW-RMD or ROW-RMD for 8 weeks. After sacrifice, biochemical analyses in serum, liver, and feces were carried out. The results showed that DOW-RMD had a greater effect on lowering cholesterol levels and lipid peroxidation in serum and lipid plaque in heart aorta than ROW-RMD. However, DOW was likely to modulate the Monascus metabolite biosynthesis pathway toward the formation of hypolipidemic yellow pigments (such as monascin and ankaflavin) rather than red pigments and the mycotoxin citrinin. In addition, the DOW with higher Mg(2+) ion was proven to absorb into DOW-RMD; however, the accumulation of Mg(2+) ions should contribute a greater hypolipidemic effect to DOW-RMD. Comprehensively, the DOW-induced metabolism modulation and the ions of DOW were a benefit to the development of safe DOW-RMD with low citrinin levels and high hypolipidemic, antiatherosclerosis, and anti-fatty liver effects.