AHLs对小球藻PSⅡ光化学活性与生化指标的影响研究

Effects of AHLs on PSⅡ Photochemistry Activity and Biochemical Indexes of Chlorella vulgaris

小球藻是一种重要的资源微藻,在水产养殖、生物能源和功能型保健食品等领域都有广泛的应用。小球藻藻际共栖细菌产生的群感信号分子N-酰基-高丝氨酸内酯类化合物(N-acyl-homoserine lactones,AHLs)不仅可以调控细菌的生物学功能,还能影响藻类的生命活动,常会引起小球藻高密度培养系统崩溃,因此研究AHLs对小球藻生理代谢的影响和机理具有重要的现实意义。本研究采用批次培养的方法,研究了100、200、400mmol/L C10-HSL(N-癸酰-L-高丝氨酸内酯)对普通海水小球藻(Chlorella vulgaris)PSⅡ光化学活性与生化指标(SOD、CAT、GPx和Mg2+-ATPase)的影响。结果显示:在C10-HSL作用下,小球藻PSⅡ光化学活性指标——最大光能转化效率Fv/Fm、实际光能转化效率Yeild及表观光合电子传递效率ETR均明显下降,而且C10-HSL对Yeild的影响强于对Fv/Fm的作用;小球藻SOD、CAT、GPx和Mg2+-ATPase活性均大致呈现先升高后降低的变化趋势,但峰值出现时间不同,C10-HSL对生化指标的影响均未表现随时间规律变化的剂量-效应关系。本研究阐明了AHLs对小球藻光合生理、抗氧化酶系统和能量代谢的影响规律,暗示AHLs引发的氧化损伤以及能量代谢紊乱可能是造成小球藻培养体系崩溃的重要原因,实验结果为小球藻无菌化健康培养与养殖体系优化提供了一定的依据。

As an excellent resource microalgae,Chlorella has wide applications for aquaculture,production of biofuel and development of functional food.AHLs（N-acyl-homoserine lactones）are known as the quorum sensing signal molecule produced by commensalism bacteria in phycosphere.AHLs are playing important roles in not only regulating the biological function of bacteria,but also affecting the life activities of algae.Therefore,AHLs could result in the high-density culture system of Chlorella collapse.A laboratory study was conducted to evaluate the effects of 100,200,400mmol/LC10-HSL（N-decanoyl-L-homoserine lactones）on PSⅡ photochemistry activity,antioxidase（SOD,CAT,GPx）activities and energy metabolism enzyme Mg^2＋-ATPase activity of the marine microalgae Chlorella vulgaris,in the photoautotrophic culture process.The results were as follows：PSⅡ photochemistry activity indicators—Fv/Fm（maximal photochemical efficiency）,Yeild（actual photochemical efficiency）and ETR（apparent photosynthetic electron transport ratio）decreased obviously under the effect of C10-HSL.C10-HSL exerted higher effect on Yeild than Fv/Fm.There was a same fluctuation trend of the enzymes activities of SOD,CAT,GPx and Mg^2＋-ATPase which increased first and then decreased,but the time of reaching peak was different.There was no regular dose-effect relationship of effect that exerted on C.vulgaris by C10-HSL over time.The concentration-dependent effect of C10-HSL on C.vulgaris was not obvious.The antioxidase activities of C.vulgaris were induced expression in different extent,which meant the microalgae was subjected to oxidative stress exerted by C10-HSL.Mg^2＋-ATPase activity of C.vulgaris fluctuated fiercely,which meant the process of ATP synthesis and ion transportation were disturbed by C10-HSL.The current research not only illuminated the changing discipline of PSⅡ photochemistry activity,antioxidase activities and energy metabolism enzyme activity of Chlorella vulgaris,but also implied that the oxidative damage and turbulence of energy metabolism were supposed to the important reasons for the collapse of C.vulgaris density-culture system.The results provided a basis for the axenic culture and cultivation system optimization of C.vulgaris.