Lipid metabolism regulation by dietary polysaccharides with different structural properties.

Lipid metabolism plays an important role in energy homeostasis maintenance in response to stress. Nowadays, hyperlipidemia-related chronic diseases such as obesity, diabetes, atherosclerosis, and fatty liver pose significant health challenges. Dietary polysaccharides (DPs) have gained attention for their effective lipid-lowering properties. This review examines the multifaceted mechanisms that DPs employ to lower lipid levels in subjects with hyperlipidemia. DPs could directly inhibit lipid intake and absorption, promote lipid excretion, and regulate key enzymes involved in lipid metabolism pathways, including triglyceride and cholesterol anabolism and catabolism, fatty acid oxidation, and bile acid synthesis. Additionally, DPs indirectly improve lipid homeostasis by modulating gut microbiota composition and alleviating oxidative stress. Moreover, the lipid-lowering mechanisms of particular structural DPs (including ß-glucan, pectin, glucomannan, inulin, arabinoxylan, and fucoidan) are summarized. The relationship between the structure and lipid-lowering activity of DPs is also discussed based on current researches. Finally, potential breakthroughs and future directions in the development of DPs in lipid-lowering activity are discussed. The paper could provide a reference for further exploring the mechanism of DPs for lipid regulations and utilizing DPs as lipid-lowering dietary ingredients.

The natural fenhexamid-resistant grey mould populations from strawberry in Zhejiang Province are dominated by Botrytis cinerea group S.

BACKGROUND: Recently, a novel clade Botrytis cinerea group S was found to be common in B. cinerea populations from Germany and New Zealand. Fenhexamid, an effective antibotrytis fungicide, has not been registered in China, but our preliminary study detected fenhexamid-resistant (HydR) isolates from strawberry in Zhejiang Province. RESULTS: Genetic identification of 639 B. cinerea isolates from strawberry found that 331 (62.9%) belonged to B. cinerea group S. The frequency of HydR isolates ranged from 0 to 37.5% among the nine locations. Of the 74 HydR isolates, 71 were B. cinerea group S and moderately resistant to fenhexamid (HydR). Seven new mutations S9G, P57A, P269L, V365A, E368D, E375K and A378T in the target gene erg27 were reported for the first time. Sixty-two (83.8%) HydR isolates simultaneously carried P57A and A378T mutations, and further transformation assays showed that integration of one copy of erg27(P57A) (,) (A378T) into a wild-type strain led to partial resistance. Detached fruit studies showed that fenhexamid at the recommended field rate could control the disease incited by moderately resistant isolates but not by highly resistant isolates. CONCLUSION: B. cinerea group S isolates are widespread in all strawberry-growing locations in Zhejiang Province. The natural HydR populations from strawberry are dominated by B. cinerea group S. © 2015 Society of Chemical Industry.

The response regulator BcSkn7 is required for vegetative differentiation and adaptation to oxidative and osmotic stresses in Botrytis cinerea.

The high-osmolarity glycerol pathway plays an important role in the responses of fungi to various environmental stresses. Saccharomyces cerevisiae Skn7 is a response regulator in the high-osmolarity glycerol pathway, which regulates the oxidative stress response, cell cycle and cell wall biosynthesis. In this study, we characterized an Skn7 orthologue BcSkn7 in Botrytis cinerea. BcSKN7 can partly restore the growth defects of S. cerevisiae SKN7 mutant and vice versa. The BcSKN7 mutant (ΔBcSkn7-1) revealed increased sensitivity to ionic osmotic and oxidative stresses and to ergosterol biosynthesis inhibitors. In addition, ΔBcSkn7-1 was also impaired dramatically in conidiation and sclerotial formation. Western blot analysis showed that BcSkn7 positively regulated the phosphorylation of BcSak1 (the orthologue of S. cerevisiae Hog1) under osmotic stress, indicating that BcSkn7 is associated with the high-osmolarity glycerol pathway in B. cinerea. In contrast with BcSak1, BcSkn7 is not involved in the regulation of B. cinerea virulence. All of the phenotypic defects of ΔBcSkn7-1 are restored by genetic complementation of the mutant with the wild-type BcSKN7. The results of this study indicate that BcSkn7 plays an important role in the regulation of vegetative differentiation and in the response to various stresses in B. cinerea.

Functional characterization of FgERG3 and FgERG5 associated with ergosterol biosynthesis, vegetative differentiation and virulence of Fusarium graminearum.

The ergosterol biosynthesis pathway is well characterized in Saccharomyces cerevisiae, while little is known about the pathway in filamentous fungi. In this study, we isolated and genetically documented biological functions of FgErg3 and FgErg5, which are located upstream of FgErg4, the enzyme catalyzing the final step of ergosterol synthesis in Fusarium graminearum. Our results demonstrated that F. graminearum contains two paralogous FgERG3 and two FgERG5 genes. FgErg3, but not FgErg5, is involved in ergosterol biosynthesis. Double deletion mutants of FgERG3 alleles or the double deletion mutants of FgERG5 alleles showed decreased conidiation and produced abnormal conidia. Fungicide susceptibility tests revealed that FgERG3 and FgERG5 mutants have increased resistance towards triadimefon. However, FgERG3 mutants exhibited increased susceptibility to tebuconazole as well as increased susceptibility to oxidative stress, paraquat and to Mg(2+). Pathogenicity tests showed that the FgERG3 and FgERG5 double deletion mutant displayed dramatically attenuated virulence although they were able to successfully colonize flowering wheat head. In addition, complementation of FgERG3 and FgERG5 genes into S. cerevisiae partially rescued the susceptibility of S. cerevisiae ERG3 and ERG5 deletion mutants towards hydroxyurea and caffeine. Taken together, our results indicate that FgERG3 and FgERG5 play a crucial role in vegetative differentiation, resistance to fungicides and virulence in F. graminearum. FgErg3 alleles, but not FgErg5 alleles, are required for ergosterol biosynthesis in the filamentous fungus F. graminearum.