The protective effects of walnut green husk polysaccharide on liver injury, vascular endothelial dysfunction and disorder of gut microbiota in high fructose-induced mice.

This study aimed to investigate the protective effects of walnut green husk polysaccharide (WGHP) on liver injury, vascular endothelial dysfunction and disorder of gut microbiota in mice induced by high fructose (HF) diet. The chemical analysis results show that the walnut green husk polysaccharide is a low molecular weight acidic heteropolysaccharide, composed mainly of glucuronic acid, arabinose and galactose. Biochemical analysis showed that WGHP significantly improved glucose metabolism and lipid metabolism and decreased oxidative stress in HF-diet induced obesity mice. Histopathological observation of liver and cardiovascular aorta confirmed the protective effects of WGHP on hepatic steatosis and vascular endothelial dysfunction. Furthermore, 16S rRNA sequencing results demonstrated that WGHP reversed the disorders of gut microbiota caused by HF, decreased the relative abundance of Verrucomicrobia and increased the relative abundance of Deferribacteres at the phylum level, decreased the relative abundance of Akkermansia, Lachnoclostridium and norank_f__Muribaculaceae and increased the relative abundance of Prevotellaceae_UCG-001, Helicobacter, Alloprevotella and Allobaculum at the genus levels. Our results indicate that WGHP may act as a functional polysaccharide for protecting liver and cardiovascular in HF-fed mice.

Physiological characterization of maize tolerance to low dose of aluminum, highlighted by promoted leaf growth.

MAIN CONCLUSION: Effects of a low aluminum (Al) dose were characterized. The Al supplement inhibited root growth but enhanced leaf growth in maize lines with different Al sensitivities. High levels of Al are phytotoxic especially in acidic soils. The beneficial effects of low Al levels have been reported in some plant species, but not in maize. Maize is relatively more sensitive to Al toxicity than other cereals. Seedlings, at the three leaf stage, of four Chinese maize foundation parent inbred lines with different Al tolerances, were exposed to complete Hoagland's nutrient solution at pH 4.5 supplemented with 48 µM Al(3+) under controlled growth conditions, and then the Al stress (AS) was removed. The leaf and root growth, root cell viability, superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ions (K(+), Ca(++) and Mg(++)), photosynthetic rate and chlorophyll, protein and malondialdehyde contents in tissues were assayed. In conclusion, a low Al dose inhibits root growth but enhances leaf growth in maize. The Al-promoted leaf growth is likely a result of increased protein synthesis, a lowered Ca(++) level, and the discharge of the growth-inhibitory factors. The Al-promoted leaf growth may be a 'memory' effect caused by the earlier AS in maize. Al causes cell wall rupture, and a loss of K(+), Ca(++) and Mg(++) from root cells. CAT is an auxiliary antioxidant enzyme that works selectively with either SOD or POD against AS-related peroxidation, depending on the maize tissue. CAT is a major antioxidant enzyme responsible for root growth, but SOD is important for leaf growth during AS and after its removal. Our results contribute to understanding how low levels of Al affect maize and Al-resistant mechanisms in maize.