Effects of 5-Azacytidine(AZA)on the Growth,Antioxidant Activities and Germination of Pellicle Cysts of Scrippsiella acuminata(Dinophyceae)

In this study,we investigated the effects of different concentrations of 5-azacytidine(AZA),a DNA methyltransferase in-hibitor,on the growth,antioxidant activities and germination of pellicle cysts of Scrippsiella acuminata.The purpose of this study is to understand the toxic effects of AZA on marine microalgae,and to demonstrate the effect of DNA methyltransferase inhibitors on the germination of pellicle cysts.Results showed that AZA inhibited the growth of S.acuminata significantly,and displaced a clear dose-dependent inhibition trend with the 96h EC50 of 146.77μmolL^(-1)(35.84mgL^(-1)).Pellicle cysts of S.acuminata were less sensitive to AZA than the vegetative cells,and the EC50 value of AZA to the germination of pellicle cysts of S.acuminata was 8.08mmolL^(-1)(1.97g L^(-1)).After exposed to AZA,the antioxidant activities in S.acuminata responded rapidly and significantly.Among them,soluble pro-tein and superoxide dismutase(SOD)were more sensitive to AZA,and significant promotions occurred after exposed to 10μmolL^(-1)AZA for 24h.Meanwhile,malondialdehyde(MDA)contents in algal cells did not change significantly after exposed to low concen-trations of AZA,but increased firstly and then decreased under high concentration of AZA.The glutathione(GSH)levels in S.acu-minata increased significantly under high concentrations of AZA,and remained unchanged at low concentrations of AZA.The results suggested that the enhanced protein level and SOD activity of S.acuminata eliminated reactive oxygen species(ROS)to a certain ex-tent,and thus protected algal cells against damages of ROS caused by AZA.

Two new glucosides from the pellicle of the walnut (Juglans regia)

A newα-tetralonyl glucoside,6'-O-acetyl-juglanoside E(1),and a new dihydrophaseic acid glucoside,dihydrophaseic acid 1-O-(6-O-acetyl)-glucopyranoside(2),together with two known ones,juglanoside E(3)and dihydrophaseic acid(4),were isolated from the pellicle of the walnut(Juglans regia).The structures of the new compounds were elucidated by comprehensive spectroscopic analysis,including IR,HRESIMS,1D and 2D NMR data.