García-Villada Libertad, Rico Marcos, Altamirano M María, Sánchez-Martín Laura, López-Rodas Victoria, Costas Eduardo
Dpto. Producción Animal (Genética), Facultad de Veterinaria, Universidad Complutense de Madrid, Avenida Puerta de Hierro s/n, Madrid E-28040, Spain.
Water Res. 2004 Apr;38(8):2207-13. doi: 10.1016/j.watres.2004.01.036.
Freshwater toxic cyanobacteria are an increasing problem to human and animal health. Control of cyanobacteria in water supply reservoirs involves the use of algaecides, such as copper sulphate, usually in a repetitive way. Repercussions of recurrent algaecide treatments on cyanobacteria population dynamics remain still unknown. We studied the adaptation of cyanobacteria to lethal doses of copper sulphate by using Microcystis aeruginosa as an experimental model. A fluctuation analysis demonstrated that copper-resistant cells arise by spontaneous mutations that occur randomly prior to exposition to copper sulphate. The rate of spontaneous mutation from copper sensitivity to resistance was 1.76 x 10(-6) mutants per cell division. Resistant mutants exhibited a diminished fitness in the absence of copper sulphate, but only these variants were able to grow at Cu(2+) concentrations higher than 5.8 microM. In addition, copper-resistant cells were significantly smaller than wild-type ones. Warnings on the long-term consequences of repetitive algaecide treatments in water supplies are suggested.
淡水有毒蓝藻对人类和动物健康构成的问题日益严重。控制供水水库中的蓝藻需要使用杀藻剂，如硫酸铜，且通常是反复使用。反复使用杀藻剂对蓝藻种群动态的影响仍然未知。我们以铜绿微囊藻为实验模型，研究了蓝藻对致死剂量硫酸铜的适应性。波动分析表明，抗铜细胞是由在接触硫酸铜之前随机发生的自发突变产生的。从铜敏感型到抗铜型的自发突变率为每细胞分裂1.76×10⁻⁶个突变体。在没有硫酸铜的情况下，抗性突变体的适应性有所降低，但只有这些变体能够在高于5.8微摩尔的铜离子浓度下生长。此外，抗铜细胞明显小于野生型细胞。文中建议对供水系统中反复使用杀藻剂的长期后果予以关注。
