ABSTRACT
Objective: To investigate the signal molecules and signal transduction involved in endophytic fungal elicitor-induced atractylodin biosynthesis and the effect of an endophytic fungal elicitor on the key enzyme activity in Atractylodes lancea. Methods: Content changes of nitric oxide (NO), salicylic acid (SA), and atractylodin were detected under the endophytic fungal elicitor treatment by plant cell suspension culture technology. Results: The endophytic fungal elicitor remarkably promoted NO burst and the biosynthesis of SA and atractyodin by activating nitric oxide synthase (NOS), phenylalanine ammonia lyase (PAL), and acetyl coenzyme A carboxylase (ACC), respectively. NOS inhibitor PBITU could inhibit the NO and SA accumulation and the atractyodin biosynthesis induced by the elicitor. And atractyodin biosynthesis could also be triggered by exogenous NO or SA. The results indicated that NO and SA were the necessary signal molecules and NO burst was mediated by NOS induced by endophytic fungal elicitor. NO quencher cPITO could effectively remove NO burst in A. lancea cell induced by endophytic fungal elicitor and notably inhibit the biosynthesis promotion of SA and atractyodin in A. lancea cell induced by endophytic fungal elicitor. Exogenous SNP could reverse the cPITO inhibition on the activity of PAL and ACC and the synthesis of SA and atractylodin. This suggested that NO was an upstream signal molecule mediated endophytic fungal elicitor to accelerate the biosynthesis of SA and atractyodin. Conclusion: Endophytic fungal elicitor mediated through NO followed by SA could promote atractyodin biosynthesis by activating ACC in A. lancea.
ABSTRACT
Objective To investigate the effects of high-fat diet on fatty acid metabolism, expression and activity of acetyl coenzyme A carboxylase (ACC) in skeletal muscle in rats. Methods Male Wistar rats aged 22-24 months were randomly divided into old control (OC) group and high-fat diet (HF) group. Male Wistar rats aged 4-5 months were selected as young control (YC) group. The rats in OC and YC groups were fed with basic diet, and the rats in HF group received high-fat diet. Insulin sensitivity was evaluated by hyperinsulinemic-euglycemic clamp technique. Skeletal muscle triglyceride was extracted and measured by an automated biochemistry analyzer. Long-chain acetyl coenzyme A (LCACoAs) were extracted from muscle and measured by a fluorospectrophotometer. Protein expressions of ACC and P-ACC were measured using SDS-PAGE and Western blot techniques. Results (1)Fasting blood glucose (FBG), fasting insulin (FINS) and free fatty acid were higher in OC group than in YC group and they increased significantly in HF group. Triglyceride (TG) and total cholesterol (TO levels were also elevated after high-fat feeding. (2)Glucose infusion rates (GIR) were reduced in OC group than in YC group, and decreased significantly after high-fat feeding. GIR was lower at the end of the 8th week than at the end of the 4th week in HF group. (3) Compared with YC group, skeletal muscle triglyceride and LCACoAs increased in OC group and increased significantly in HF group. (4)No alterations of protein levels of ACC in skeletal muscle were detected among three groups (P>0.05). The protein levels of P-ACC in skeletal muscle were lower in OC group, and much lower in HF group than in YC group (P<0.05 or P<0.01). Conclusions Compared with young rats, abnormal fatty acid metabolism and insulin resistance always exist in aged rats. High-fat feeding results in a significant increase in lipid content in skeletal muscle. Alterations of ACC activity may contribute to fat accumulation in skeletal muscle and insulin resistance.