Carlos Eduardo A Souza
Carlos Eduardo A Souza has a DVM from Ceara State University completed his PhD from Federal University of Ceará (UFC)/Pennsylvania State University and Post-doctoral studies from UFC and Wayne State University. He is the Head of the School of Veterinary Medicine at Cisne University (Brazil). He has published more than 20 papers in reputed journals and serving as Reviewer of several journals such as Animal Reproduction Science and Journal of Proteomics.
This research describes the proteomic profile of the seminal plasma of Dorper rams raised in northeastern Brazil. Semen was collected from 10 sexually mature rams and proteins were analyzed by 2D electrophoresis and tandem mass spectrometry. Major spots were digested with trypsin and identified by MS/MS. Gels had an average of 314±9 spots within the 4-7 pH range with 190 spots detected consistently in gels from all males. Most spots were in the acidic side (215±16) ranging from 14 to 180 kDa. Among these, 97 spots were identified representing 53 proteins including clusterin, albumin, peroxiredoxin, lactoferrin, lactoperoxidase, zync-alpha-2-glycoprotein, glutathione peroxidase, heat-shock proteins, bodhesins and ram seminal vesicle proteins (RSVP) both 14 and 22. Gene ontology analysis showed that these proteins were mainly secreted (78.3%) involved in binding (50.3%) and mediating cellular processes (44.8%), many of them with antioxidant and antibacterial properties. Bodhesins and RSVP14 formed spot clusters (~14 kDa, pI 5.0-5.9) and were the most abundant proteins in the gels in terms of optical density. Altogether, RSVP spot intensities represented 23.8% of the combined intensity of all spots followed by bodhesins with 18.9%. Tryptic peptides resulting from RSVP digestion matched mainly to fibronectin type II domains in the protein sequence while those from bodhesins matched to CUB domain. These major proteins are secreted mainly by accessory sex glands and play a role in sperm capacitation. In summary, Dorper seminal proteomic findings suggest that seminal proteins are involved in a range of functions including sperm capacitation, protection, sperm motility and fertilization.