Biomarker discovery and proteomic evaluation of cadmium toxicity on a collembolan species, Paronychiurus kimi (Lee)†

The goal of this study was to identify promising new biomarkers of cadmium by identifying differentially expressed proteins in Paronychiurus kimi after exposure to cadmium. Through proteomic analysis of P. kimi using 1-D PAGE and nano-LC-MS/MS, 36 downregulated proteins and 40 upregulated proteins were found. Some of the downregulated and upregulated proteins were verified by LC-MS/MS analysis after 2-D PAGE. Downregulated proteins in response to cadmium exposure were involved in glycolysis and energy metabolism, chaperones, transcription, reproduction, and neuron growth. In contrast, proteins involved in glycolysis and energy production, neurogenesis, defense systems response to bacteria, and protein biosynthesis were upregulated in cadmium-treated collembolans. Cubulin may be a potential biomarker for the detection of cadmium in P. kimi since this biomarker was able to low levels (3.5 mg/kg) of cadmium. The 14-3-3 ζ was also found to be a potential biomarker for the detection of medium levels (14 mg/kg) of cadmium. Collembolans may be an alternative tool to humans because many collembolans proteins show a high homology to human proteins.