Boyd Windy A, Cole Russell D, Anderson Gary L, Williams Phillip L
Department of Environmental Health Science, University of Georgia, Athens, Georgia 30602-2102, USA.
Environ Toxicol Chem. 2003 Dec;22(12):3049-55. doi: 10.1897/02-565.
Caenorhabditis elegans, a nonparasitic soil nematode, was used to assess the combined effects of metal exposures and food availability on behavior. Movement was monitored using a computer tracking system after exposures to Cu, Pb, or Cd while feeding was measured as a change in optical density (deltaOD) of bacteria suspensions over the exposure period. After 24-h exposures at high and low bacteria concentrations, movement was decreased in a concentration-dependent fashion by Pb and Cd but feeding reductions were not directly proportional to exposure concentrations. Copper exposure induced concentration-dependent declines in feeding and movement regardless of bacteria concentration. The impact of 24-h metal exposures was apparently reduced by increasing food availability. Therefore, exposures were shortened to 4 h in an attempt to minimize starvation effects on movement. Although nematodes were immobilized following 24 h of food depravation, worms deprived of food during the 4-h exposure continued to feed and move after exposure. A bead-ingestion assay after 4-h exposures was also used as an additional means of assessing the effects of metals on feeding behavior. Ingestion was significantly reduced by all concentrations of metals tested, indicating its sensitivity as a sublethal assay. Feeding (deltaOD) during exposures exhibited similar trends as ingestion but was slightly less sensitive, while movement was the least sensitive assay of 4-h metal exposures to C. elegans. Assessment of multiple sublethal endpoints allowed for the determination of the separate and interactive effects of metals and food availability on C. elegans behavior.
秀丽隐杆线虫是一种非寄生性土壤线虫，被用于评估金属暴露和食物可获得性对行为的综合影响。在暴露于铜、铅或镉后，使用计算机跟踪系统监测其运动，而摄食则通过暴露期间细菌悬液的光密度变化（ΔOD）来衡量。在高、低细菌浓度下暴露24小时后，铅和镉以浓度依赖的方式降低了运动，但摄食减少与暴露浓度并非直接成比例。无论细菌浓度如何，铜暴露都会导致摄食和运动呈浓度依赖性下降。增加食物可获得性明显降低了24小时金属暴露的影响。因此，将暴露时间缩短至4小时，以尽量减少饥饿对运动的影响。尽管线虫在食物剥夺24小时后会不动，但在4小时暴露期间被剥夺食物的线虫在暴露后仍继续摄食和运动。4小时暴露后的珠子摄取试验也被用作评估金属对摄食行为影响的额外方法。所有测试浓度的金属都显著降低了摄取，表明其作为亚致死试验的敏感性。暴露期间的摄食（ΔOD）表现出与摄取相似的趋势，但敏感性略低，而运动是4小时金属暴露对秀丽隐杆线虫最不敏感的试验。评估多个亚致死终点有助于确定金属和食物可获得性对秀丽隐杆线虫行为的单独和交互影响。
