微囊藻碳酸酐酶活性在不同环境因素下的调节与适应

Modulation and adaptation of carbonic anhydrase activity in Microcystis spp. under different environmental factors

测定了3种微囊藻水华中的优势种类,即铜锈微囊藻(Microcystis aeruginosaK櫣tz .) ,绿色微囊藻(Microcystis viridis(A. Br .)Lemm) ,惠氏微囊藻(Microcystis wesenbergii(Kom.)Kom.) ,以及微囊藻573(Microcystissp.573)的碳酸酐酶活性;研究了无机碳、pH、温度、光强、N/P比等环境因素和外源葡萄糖对铜锈微囊藻碳酸酐酶活性的影响,发现微囊藻碳酸酐酶活性受环境中碳酸氢根浓度的调节,故推断碳酸氢根是铜锈微囊藻利用的主要无机碳形式;相比添加葡萄糖进行混合营养培养的细胞,无外源葡萄糖和暗饥饿培养的微囊藻细胞会产生高约6倍的碳酸酐酶活性;光强的改变也会影响碳酸酐酶的活性。

The carbonic anhydrase （CA） activities were determined in three cyanobacterial species, namely Microcystis aeruginosa KUtz, Microcystis viridis （A. Br. ）Lemm, Microcystis wesenbergii （Kom.） Kom, which are dominant in a lake （Lake Dianchi） subject to major blooms. In more detailed experiments on M. aeruginosa, the effects of inorganic carbon, pH, temperature, nitrogen/phosphorus ratio, glucose, and light intensity on CA activity were also investigated. The results showed that the CA activity of M. aeruginosa was influenced dramatically by the concentration of bicarbonate. Consequently, it is suggested that bicarbonate ions were the main form of inorganic carbon M. aeruginosa could utilize. Cultures grown in the dark exhibited CA activity 6 times higher than that of cells cultured mixotrophically with the addition of glucose. Features of eutrophic water bodies promote an increase in CA activity, and the resulting higher CA activity would accelerate the utilization of inorganic carbon and favour the growth and blooming of Microcystis spp. in eutrophic lakes. Although the experiments were carried out under controlled experimental conditions, they may provide some basic data that will prove useful for the control of cyanobacterial blooms in nature.