Levy Jacqueline L, Stauber Jennifer L, Jolley Dianne F
Centre for Environmental Contaminants Research, CSIRO Land and Water, Private Mail Bag 7, Bangor, NSW, Australia.
Sci Total Environ. 2007 Nov 15;387(1-3):141-54. doi: 10.1016/j.scitotenv.2007.07.016. Epub 2007 Aug 31.
Microalgae are sensitive indicators of environmental change and, as the basis of most freshwater and marine ecosystems, are widely used in the assessment of risk and development of environmental regulations for metals. However, interspecies differences in sensitivity to metals are not well understood. The relationship between metal-algal cell binding and copper sensitivity of marine microalgae was investigated using a series of 72-h growth-rate inhibition bioassays and short-term (1-h) uptake studies. A range of marine algae from different taxonomic groups were screened to determine whether copper adsorption to the cell membrane was influenced by biotic factors, such as the ultrastructure of cell walls and cell size. Minutocellus polymorphus was the most sensitive species to copper and Dunaliella tertiolecta the least sensitive, with 72-h IC50 values (concentration to inhibit growth-rate by 50%) of 0.6 and 530 microg Cu/L, respectively. Copper solution-cell partition coefficients at equilibrium (K(d)) were calculated for six species of algae on a per cell and surface area basis. The largest and smallest cells had the lowest and highest K(d) values, respectively (on a surface area basis), with a general (non-linear) trend of decreasing K(d) with increasing cell surface area (p=0.026), however, no relationship was found between K(d) and copper sensitivity, nor cell size and copper sensitivity. Interspecies differences in copper sensitivity were not related to cell size, cell wall type, taxonomic group or K(d) values. The differences in sensitivity may be due to differences in uptake rates across the plasma membrane, in internal binding mechanisms and/or detoxification mechanisms between the different microalgal species.
微藻是环境变化的敏感指标，作为大多数淡水和海洋生态系统的基础，被广泛用于金属风险评估和环境法规制定。然而，不同物种对金属的敏感性差异尚未得到充分了解。通过一系列72小时生长速率抑制生物测定和短期（1小时）摄取研究，研究了海洋微藻中金属与藻细胞结合和铜敏感性之间的关系。筛选了一系列不同分类群的海洋藻类，以确定铜吸附到细胞膜上是否受生物因素影响，如细胞壁超微结构和细胞大小。多形微胞藻是对铜最敏感的物种，而盐生杜氏藻最不敏感，其72小时IC50值（抑制生长速率50%的浓度）分别为0.6和530微克铜/升。基于每个细胞和表面积计算了六种藻类在平衡时的铜溶液-细胞分配系数（K(d)）。最大和最小的细胞分别具有最低和最高的K(d)值（基于表面积），随着细胞表面积增加，K(d)呈总体（非线性）下降趋势（p = 0.026），然而，未发现K(d)与铜敏感性之间的关系，也未发现细胞大小与铜敏感性之间的关系。不同物种对铜的敏感性差异与细胞大小、细胞壁类型、分类群或K(d)值无关。敏感性差异可能是由于不同微藻物种之间质膜摄取速率、内部结合机制和/或解毒机制的差异。
