Dietary fermented products using koji mold and sweet potato-shochu distillery by-product promotes hepatic and serum cholesterol levels and modulates gut microbiota in mice fed a high-cholesterol diet.

It has been reported that fermented products (FPs) prepared from sweet potato-shochu distillery by-product suppressed weight gain and decreased serum cholesterol levels in mice under normal dietary conditions. Furthermore, from the information gained from the above data regarding health benefits of the FPs, the aim of this study was evaluating the effects of dietary FPs on lipid accumulation and gut microbiota in mice with or without cholesterol-load in the diet. C57BL/6N mice were fed normal (CO) diet, CO with 10% FPs (CO + FPs) diet, cholesterol loaded (HC) diet, or HC with 10% FPs (HC + FPs) diet for 8 weeks. The mice were then euthanized, and blood samples, tissue samples, and feces were collected. The adipose tissue weight and liver triglyceride levels in the HC + FPs diet groups were significantly reduced compared to that in the HC diet groups. However, FPs significantly increased the serum non-high-density lipoprotein cholesterol (HDL-C) levels, the ratio of non-HDL-C to HDL-C and hepatic total cholesterol levels in mice fed cholesterol-loaded diet compared with that of the HC diet group. Since dietary FPs significantly decreased the protein expression levels of cholesterol 7 alpha-hydroxylase 1 in the HC + FPs diet groups, the cholesterol accumulation in FPs group may be explained by insufficient catabolism from cholesterol to bile acid. In addition, the dietary FPs tended to increase Clostridium cluster IV and XIVa, which are butyrate-producing bacteria. Related to the result, n-butyrate was significantly increased in the CO + FPs and the HC + FPs diet groups compared to their respective control groups. These findings suggested that dietary FPs modulated the lipid pool and gut microbiota.

Effect of pepA deletion and overexpression in Aspergillus luchuensis on sweet potato shochu brewing.

The mash of sweet potato shochu (Japanese distilled spirit) has a low pH value because the shochu koji mold produces a large amount of citric acid, which prevents germ contamination. In this study, we examined acid protease PepA's role in shochu production. For this purpose, we constructed pepA deletion and overexpression strains, using a black koji mold Aspergillus luchuensis RIB 2604 (NBRC 4314), with the Agrobacterium-mediated transformation method. The rice koji, prepared using a pepA disruptant (ΔpepA) and pepA-overexpressing strain (OEpepA), demonstrated 1/2- and 24-fold acid protease activities compared to that prepared using the parental strain, respectively. A small-scale test of sweet potato shochu brewing indicated the mash of ΔpepA had a lower amino acid concentration, while the mash of OEpepA had a higher concentration than that produced by the parental strain. Therefore, the mash amino acid concentrations were proportional to these strains' acid proteases activities. After distilling these mashes, we examined each shochu's aroma components. Shochu prepared using ΔpepA had relatively higher aroma components, such as alcohol and ester, compared to that prepared using parental strains. Meanwhile, shochu prepared using OEpepA had lower aroma components than that prepared using the parental strains. Based on these results, the amount of shochu aroma components showed an inverse correlation to the acid protease activity in the mash. Thus, the koji mold's acid protease content had a greater influence on the aroma qualities of sweet potato shochu. Accordingly, we have discussed the possibility of the breeding of shochu koji mold with acid protease as an indicator.

Notch-, Wingless-, and Dpp-mediated signaling pathways are required for functional specification of Drosophila midgut cells.

The mechanisms for cell fate determination have been extensively studied whereas little is known about the mechanism through which functional specificity is established. In the Drosophila midgut, copper cells provide an excellent model system to examine this mechanism. Copper is an essential element for the activity of a number of physiologically important enzymes including Cu/Zn-superoxide dismutase, cytochrome c oxidase, and dopamine-beta-hydroxylase. Drosophila copper cells are involved in two distinct functions, i.e., copper absorption and acid secretion, which are visualized as a fluorescent signal and a color change of a pH indicator dye, respectively. Here we show that the absorptive function is established through two independent pathways, the Notch signaling pathway in adjacent interstitial cells and the Wingless signaling pathway in copper cells. Furthermore, the other function, acid secretion, is regulated through the Decapentaplegic and Wingless signaling pathways in interstitial cells. Our results clearly indicate that normal morphological development is insufficient for functional maturation, and that subsequent functional specification is achieved through several independent pathways. These results provide valuable insights into the molecular mechanism underlying functional specification.