Hye-Min Kanga, Jin-Sol Leea, Young Hwan Leea, Min-Sub Kima, Heum Gi Parkb, Chang-Bum Jeonga,*, and Jae-Seong Leea,*
aDepartment of Biological Science, College of Science, Sungkyunkwan University, Suwon 16419, South Korea
b Department of Marine Resource Development, College of Life Sciences, GangneungWonju National University, Gangneung 25457, South Korea
*Corresponding authors. Chang-Bum Jeong, Jae-Seong Lee
Abstract
Although several studies have reported on different interspecific sensitivities in response to various toxicants, the response mechanisms are still poorly understood. Here, we investigate the interspecific toxicity of cadmium (Cd) and its mechanism using three marine rotifer Brachionus spp. that are distinguishable by body size, which is considered the most significant indicator of phenotypic difference. The body sizes of B. plicatilis, B. koreanus, and B. rotundiformis are significantly different throughout their life cycles (egg, neonate, and adult), with the smaller rotifer exhibiting higher sensitivity to Cd. To investigate the mechanisms that result in body size-dependent tolerance to Cd, metabolic and Cd bioaccumulation rates were investigated. Both rates have shown a significant correlation with body size, indicating that body size and its variables are important factors in determining Cd tolerance in Brachionus spp. In addition, similar patterns that further explain body size-dependent tolerance are shown in the phosphorylation status of mitogen-activated protein kinases, reactive oxygen species level, and antioxidant enzymatic activities. Our study provides valuable insight into size- and species-dependent toxicity mechanisms of species in the same genus.
Keywords: Brachionus plicatilis, Brachionus koreanus, Brachionus rotundiformis, body size, tolerance, cadmium