APPLICATION OF PROTEOMICS IN CARP SEMEN EXAMINATION, BASIC AND APPLIED

Proteomics is defined as the science dealing with the proteome, the protein component encoded by the genome. To date, the methodological approach for protein characterization in fish semen has been based on two major steps: purification of proteins using numerous liquid preparative chromatographic methods and the identification of proteins using Edman sequencing. Purification of carp seminal proteins and their identification through sequencing has led to the identification of the major proteins of carp semen. The introduction of proteomic methods (two dimensional electrophoresis and mass spectrometry) for carp semen analysis allowed for the identification of 186 proteins in seminal plasma and 348 in spermatozoa. Most of the identified proteins were described for the first time for this species. This is, so far, the largest catalogue of carp semen proteins. The quantitative comparison of carp blood and seminal plasma proteome performed using 2D-DIGE revealed that the majority of seminal plasma proteins were similar to blood proteins. Out of 1220 protein spots, 99 proteins were specific to carp seminal plasma. Their presence is probably related to their specific function within the reproductive tract of fish, i.e. control of spermatogenesis and sperm motility, maintenance of sperm membrane integrity or sperm antioxidant protection. Application of the proteomic analysis allowed for monitoring the changes in the proteome of carp semen due to cryopreservation, resulting in the identification of 186 proteins released from the spermatozoa after freezing. These proteins may be potential indicators of sperm cryodamage and/or the usefulness of sperm for cryopreservation.