Proteomic studies on the swimbladder of the European eel (Anguilla anguilla)

The swimbladder of fish is a vital organ that along with gas glands in the swimbladder wall enables key physiological functions including buoyance, diving and coping with different hydrostatic pressures. Specific intramural glands provide gas for regulating gas pressure in the swimming bladder. Transcriptomic analysis have revealed evidence at the RNA level but no specific studies at the protein level have been carried out so far. Herein, it was the aim of the study to show swimbladder proteins of the European eel by label-free LC/MS (Q-Exactive Plus) that resulted in the identification of 6,223 protein groups. Neurotransmitter receptors and -transporters were enriched in the membrane fraction and enzymes for gas production were observed. The list of identified proteins may represent a useful tool for further proteomics experiments on this organ.