Ekoiz-Berrilur Consortium, CBET Res. Grp. Zoology & Animal Cell Biology Dept., Science & Technol. Fac., University of the Basque Country (UPV/EHU), Sarriena 48940 Leioa-Bizkaia, Basque Country, Spain.
Sci Total Environ. 2013 Apr 15;450-451:39-50. doi: 10.1016/j.scitotenv.2013.01.060. Epub 2013 Mar 1.
The social amoeba Dictyostelium discoideum has been proposed for assessing stress responses to pollutants in soil and it has already been successfully employed in the aquatic environment. Presently, we developed the DDDC assay (D. discoideum developmental cycle assay) for both soil toxicity assessment and soil health screening. The DDDC assay is primarily aimed at determining the capacity of D. discoideum to undergo its developmental programme forming a fruiting body, measured in terms of fruiting body formation inhibition and fruiting body size factor, which may be considered an indication of its ecological fitness (potential for spore dispersal). A second objective of the solid phase DDDC assay is to identify potential mechanisms of toxic action on the developmental cycle, for which three checkpoints are examined: (a) aggregation arrest, (b) migration arrest, and (c) culmination arrest. Presently, conditions for the DDDC assay such as soil texture, soil water content, soil pH, food availability and incubation time were investigated and optimized. In addition, both solid and liquid phase variants of the DDDC assay were applied to assess the toxicity of Hg, at regulatory concentrations. The developmental cycle and ecological fitness were affected from the exposure to 0.3 mg Hg/kg dry-wt soil onwards. The DDDC assay has been shown to be a high sensitivity test.
土壤污染物应激反应评估中拟选用变形黏菌（Dictyostelium discoideum），该方法已成功应用于水生环境。目前，我们开发了 DDDC 检测法（变形黏菌发育周期检测法），用于土壤毒性评估和土壤健康筛查。DDDC 检测法主要用于测定变形黏菌发育成子实体的能力，其通过抑制子实体形成和子实体大小因子来衡量，这可被视为其生态适应性（孢子扩散潜力）的指标。固相 DDDC 检测法的第二个目的是确定对发育周期的潜在毒性作用机制，为此检查了三个检查点：（a）聚集抑制，（b）迁移抑制，和（c） culmination 抑制。目前，研究并优化了 DDDC 检测法的条件，如土壤质地、土壤含水量、土壤 pH 值、食物供应和孵化时间。此外，还应用固相和液相 DDDC 检测法评估了 Hg 的毒性，其浓度处于监管范围内。从暴露于 0.3 mg Hg/kg 干重土壤开始，发育周期和生态适应性受到影响。DDDC 检测法显示出高灵敏度。
