Determination of the protein expression profiles of Propsilocerus akamusi (Tokunaga) Malpighian tubules response to cadmium stress by iTRAQ coupled LC-MS/MS.

UNLABELLED

Propsilocerus akamusi (Tokunaga) is an important prey species for fish and aquatic birds, which represent an important link in the aquatic food chain as other species of Chironomidae. Malpighian tubules (MT) play an important role in metabolism and detoxification of harmful compounds and metal accumulation. Our previous studies have reported that P. akamusi have an extraordinary resistance to Cd. In this paper, iTRAQ-based proteomics technology was first used to study the differential proteomics of MT of Propsilocerus akamusi under sublethal Cd stress for different time courses. 118 differential expressed proteins (DEPs) were identified through LC-MS/MS and further classified into 26 GO functional groups. Our results showed that metabolic process was the main biological functional categories. Cluster of orthologous groups of proteins (COG) analysis was also performed based on the number of unique proteins identified in each functional category, 21 metabolism-related DEPs were identified. P. akamusi adapted to Cd stress mainly by inducing the processes of lipid metabolism of MT and lipid may play a possible protection role in cadmium resistance in MT. The results provide important information for research on molecular mechanisms of Cd-stress adaption in Malpighian tubules of P. akamusi.

BIOLOGICAL SIGNIFICANCE

Propsilocerus akamusi (old species name: Tokunagayusurika akamusi) is an important prey species for fish and aquatic birds, which represent an important link in the aquatic food web as other species of Chironomidae. Malpighian tubules constitute a versatile organ which is able to exert excretory of chemical compounds, acting in the insect metabolism and detoxification of harmful compounds and metal accumulation. Our previous studies have reported that P. akamusi have an extraordinary resistance to Cd. However, up to now, there has been a lack of research on the molecular mechanisms of adaption to Cd stress in the Malpighian tubules of this species. Study on the adaptive mechanisms to Cd stress in Malpighian tubules of Propsilocerus akamusi through comparative proteome analysis is one important way to solve this problem. The aim of the present study was to understand the molecular mechanisms of adaption of the Malpighian tubules of P. akamusi exposed to Cd stress and assess the high expression of proteins involved in cellular adaptation to Cd stress. This will provide information about how this organ is responding to disturbances of contaminated ecosystems.