Cd2+胁迫下中肋骨条藻细胞内多胺的生理响应

通过室内添加Cd2+培养中肋骨条藻(Skeletonema costatum),开展了Cd2+胁迫对中肋骨条藻生长的影响及藻细胞内超氧化物歧化酶(SOD)、二胺氧化酶(DAO)、多胺氧化酶(PAO)的活性以及丙二醛(MDA)和各形态多胺含量变化的实验,以探究多胺对于海洋微藻在重金属胁迫下的响应及生理作用.结果显示,Cd2+对中肋骨条藻的生长产生胁迫作用,且Cd2+浓度越大对藻细胞生长的抑制作用越强.Cd2+胁迫下中肋骨条藻细胞内MDA含量略有升高,SOD活性显著降低,DAO和PAO活性分别增强.随着Cd2+胁迫作用的增强,藻细胞内游离态腐胺(Put)、亚精胺(Spd)、精胺(Spm)含量先降低后升高;结合态Put、Spd和Spm含量先升高后降低;束缚态Put、Spm和Spd含量及Put总量和Spm总量升高.表明Cd2+胁迫会导致中肋骨条藻细胞产生氧化损害,同时细胞内DAO和PAO活性的增强以及游离态Put、束缚态Spd和Spm、Put总量和Spm总量的升高可能会增强藻细胞抵抗Cd2+胁迫的能力.

Polyamines response to Cd2+ stress and their physiological roles in Skeletonema Costatum

Culture experiments were carried out about the effects of Cd2+ stress on the growth of Skeletonema costatum, in the meanwhile, the activity of dismutase (SOD), diamine oxidase (DAO), polyamine oxidase (PAO), and the contents of malondialdehyde (MDA) and various forms of polyamines extracted from algae cells were monitored. It aimed to explore the response and physiological roles of polyamines to the heavy metal stress in microalgae. The results showed that Cd2+ inhibited the growth of Skeletonema costatum, and the greater the concentration was, the stronger the inhibition would be. With the enhancement of Cd2+ stress, MDA content in the Skeletonema costatum cell increased slightly, SOD activity reduced significantly and DAO, PAO activity enhanced respectively. As the effect of Cd2+ stress strengthen, the contents of free putrescine (Put), spermidine (Spd) and spermine (Spm) decreased firstly and increased subsequently; conjugated Put, Spd and Spm contents increased at first and then decreased. However, bound Put, Spm and Spd as well as total Put and total Spm kept increasing. It suggested that Cd2+ stress caused oxidative damage to Skeletonema costatum cells. Meanwhile, the enhancement of DAO and PAO activity as well as the increasement of free Put, bound Spd and Spm, total Put and total Spm would enhance the resistance ability of Skeletonema costatum to Cd2+ stress.