盐度和纳米颗粒物nC60联合作用对铜绿微囊藻光合作用、氧化应激和微囊藻毒素释放的影响

Combined Effects of Salinity and Nanoparticles nC60 on Photosynthesis, Oxidative Stress and Microcystin Release of Microcystis Aeruginosa

为了探讨在盐度存在情况下,纳米颗粒物nC60对微藻的毒性效应,以铜绿微囊藻(Microcystis aeruginosa)为材料,研究盐度和nC60对M.aeruginosa生长、细胞内外藻毒素含量、叶绿素a含量、藻胆蛋白含量、活性氧水平、丙二醛含量、谷胱甘肽还原酶活性、谷胱甘肽过氧化物酶活性以及超氧化物歧化酶活性的影响。结果表明,低浓度的nC60(0.04 mg/L)对M.aeruginosa的生长表现为先促进后抑制作用,中高浓度的nC60抑制M.aeruginosa的生长,并呈剂量-效应关系。盐度和低剂量nC60联合作用M.aeruginosa后,盐度增强了低浓度nC60对M.aeruginosa的毒性效应,降低了藻细胞密度和光合色素含量,增加了细胞内活性氧和丙二醛含量,加剧了细胞膜的损伤,促进了微囊藻毒素的产生和释放,增加了细胞内抗氧化酶活性,影响了抗氧化酶基因sod和gsh的表达。综上,水介质中盐度的存在会影响nC60对铜绿微囊藻的毒性,因此,在C60生产和使用中不能忽视环境因素与纳米材料对生物体的共同作用。

The effects of salinity on photosynthesis,oxidative stress and microsystin production in Microcystis aeruginosa under nC60 stress were investigated.Algal growth,intracellular microcystin content,extracellular microcystin content,chlorophyll-a content,phycobiliprotein content,reactive oxygen species(ROS)level,malondialdehyde(MDA)content,glutathione reductase(GR)activity,glutathione peroxidate(GPx)activity and superoxide dismutase(SOD)activity were analyzed.Results showed that low-concentration nC60(0.04 mg/L)increased the growth of M.aeruginosa at the initial period.However,the cell density of M.aeruginosa decreased after continuous exposure to salinity.Medium and high concentration nC60(0.16~2.5 mg/L)inhibited the growth of M.aeruginosa in a dose-dependent manner.Moreover,the salinity exacerbated the negative effect of low-concentration nC60 on M.aeruginosa.Compared to nC60 treatment,salinity decreased the cell density and pigment content.Salinity increased ROS level and MDA content,which showed that nC60 and salinity damaged the cytomembrane.This damage contributed to the release of intracellular toxin to the culture medium.In addition,salinity increased the activities of GR,GPx and SOD.The transcript levels of sod and gsh were also increased after exposure to salinity.Results indicated that salinity could influence the negative effect of nC60 on M.Aeruginosa.Therefore,the combined effect of environmental factors and nanomaterials on organisms should not be neglected in the production and use of C60.