在不同营养条件下铜绿微囊藻对模拟微重力胁迫的响应

THE EFFECTS OF SIMULATED MICROGRAVITY ON MICROCYSTIS AERUGINOSA|DEPENDING ON THE NUTRIENT CONCENTRATIONS OF MEDIUM

  • 摘要: 通过测定在不同重力水平和营养条件下培养的铜绿微囊藻(Microcystis aeruginosa)的各项生理生化指标,研究了培养基的营养物质浓度对微囊藻细胞响应模拟微重力胁迫的影响。结果表明,在正常浓度的BG-11(富营养)和营养盐浓度减为1/10的BG-11(贫营养)培养基中培养的微囊藻对模拟微重力胁迫都很敏感,培养2d后多项生理生化指标显著改变;但是在富营养和贫营养条件下,模拟微重力的作用效果是截然不同的。对培养在BG-11中的微囊藻细胞来说,模拟微重力抑制其生长和光合活性,导致细胞内色素(叶绿素a和类胡萝卜素)、蛋白(藻蓝蛋白和可溶性蛋白)和毒素含量显著升高,向外分泌的毒素含量降低;而对培养在1/10BG-11中的藻细胞来说,模拟微重力促进其生长和光合活性,导致细胞内色素、蛋白和毒素含量降低,并使得毒素分泌增强。模拟微重力或营养限制单独作用所造成的影响相似,且后者的作用效果强于前者。当二者同时存在时,模拟微重力可以部分抵消营养限制对微囊藻生长和代谢的影响,这可能是由于模拟微重力下藻细胞的生长受到抑制而导致营养需求降低,也可能是由于模拟微重力提高了藻细胞利用营养物质的效率。总之,微囊藻对模拟微重力胁迫的响应与培养基的营养条件有关。

     

    Abstract: In order to determine the interaction between nutrient concentration and simulated microgravity (SMG), Microcystisaeruginosa, cultured under rich and low nutrient medium (BG-11 and 1/10 BG-11 medium), were treated withdifferent gravity conditions. Both of M. aeruginosa in BG-11 and 1/10 BG-11 were sensitive to SMG. Their growth andmetabolism changed significantly after 2day-treatments. The effects of SMG varied significantly with the nutrient concentrationsof medium. For M. aeruginosa cultured in BG-11, SMG led to the decreased cell number and photochemicalefficiency of PS II as well as the increased cellular concentrations of chlorophyll a, carotenoid, phycocyanin, solubleprotein and microcystin. The SMG induced changes of cells in 1/10 BG-11 were contrary to the above-mentionedchanges of cells in BG-11. In1/10 BG-11, SMG led to the increased cell number and photochemical efficiency of PS IIas well as the decreased cellular concentrations of chlorophyll a, carotenoid, phycocyanin, soluble protein and microcystin.The effects of SMG and nutrient limitation were alike when they were applied to M. aeruginosa separately. Theinfluences of nutrient limitation were stronger than those of SMG. Under SMG, maybe the nutrient demand of cells wasreduced, as a result of the suppressed growth and photochemical activity. Otherwise, SMG might enable cells to usenutriments more effectively. Thus, SMG could alleviate the stress of low nutrient medium to M. aeruginosa. Collectively,these findings supported that the nutrient concentration of medium could significantly affect the responses of M.aeruginosa to SMG.

     

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