[
International Worm Meeting,
2011]
Nickel is one of the most prevalent heavy metal contaminants in the dust floating in the air we breath, in soils, and in many waterways. Contamination continues to increase largely due to human activities like mining, manufacturing, and waste management. Ni2+ is a carcinogen to plants and animals, and a major concern for the health and safety both of humans and food crops. In addition to mutagenesis and cancer, nickel exposure leads to a variety of other deleterious health conditions. In collaboration with the United States Geological Survey, an assay to evaluate the effects of substrate bound nickel and soluble nickel on survival, growth, and fecundity using C. elegans and Pristionchus pacificus has been developed. Synchronized L1 (C. elegans) or J2 (P. pacificus) larvae were added to sediment and water samples in twelve-well tissue culture plates with a defined amount of freshly killed bacteria as a food source. Animals were grown for 96 hours at 20degC and harvested. Harvested animals were assayed for survival, growth, and fertility. Growth in eight sediment-types collected at discrete uncontaminated sites along the Missouri/Mississippi river basin suggests that both nematodes grow well in organic based sediments and less well in more sandy/inorganic based sediments. Growth in sediments spiked with increasing amounts of environmentally relevant levels of sediment-bound nickel showed that C. elegans was highly sensitive to nickel in the environment of the sediment. Treatment was lethal prior to adulthood. Growth in nickel spiked liquid media with freshly killed food and cholesterol, i.e. hard H20 pH 7.5, distilled (DI) H20, SB Media (hard H20), and SB Media (DI H20), showed that C. elegans has a strong tolerance for environmentally relevant levels of soluble nickel. Adult survivors of nickel treatments showed no significant effects on adult length/width measurements or the presence of fertilized eggs in the uterus. As nickel has other known cell stress effects, we will also assay total germline apoptosis as an measure of DNA damage.