Two-dimensional polyacrylamide gel electrophoresis of bovine semen after cryopreservation in half- milliliter straws

Protein profile as a quality indicator of cryopreserved semen from Tambaqui Colossoma macropomum (Cuvier, 1818)

The aim of this study was to evaluate the association between proteins in the seminal plasma of tambaqui Colossoma macropomum (Cuvier, 1818) with seminal quality indicators after thawing. The semen was cryopreserved with a dilution based on BTS with 8% DMSO. A 200 µL sample of semen from each animal was diluted in 800 µL BTS, centrifuged at 800 rpm, and the supernatant was cryopreserved to further analyze of the protein profile of seminal plasma through one-dimensional electrophoresis (SDS-PAGE). After 15 days of cryopreservation, a cryopreserved semen straw was thawed to analyze both qualitative and quantitative parameters. When considering all collections, the SDS-PAGE identified 15 protein bands in the seminal plasma of tambaqui. When the interaction (presence or absence) between proteins observed in the seminal plasma and the post thawed spermatic parameters was evaluated, we observed a great influence of the presence of proteins on spermatic quality. A greater (P<0.05) fertilization rate was observed with the presence of proteins 12, 34, 44, 85, and 90 kDa. Proteins in seminal plasma of tambaqui influenced the spermatic quality after thawing, and thus, they can be utilized as an indicator of sperm quality, especially the proteins with a molecular weight ≤ 50 kDa.

Monthly variations in ovine seminal plasma proteins analyzed by two-dimensional polyacrylamide gel electrophoresis

This study was conducted to evaluate monthly changes in the ram seminal plasma protein profile using two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) with a polyacrylamide linear gradient gel. Likewise, comparative analyses of the protein composition of ovine seminal plasma (SP) from ejaculates obtained along the year, and its relationship with sperm motility, viability and concentration of ejaculate were carried out. Western-blot analysis was performed to specifically detect P14, a ram SP protein postulated to be involved in sperm capacitation and gamete interaction [Barrios B, Fernández-Juan M, Muiño-Blanco T, Cebrián-Pérez JA. Immunocytochemical localization and biochemical characterization of two seminal plasma proteins which protect ram spermatozoa against cold-shock. J Androl 2005;26:539-49], and its variations along the year have also been established. The experiment was carried out from May 2003 to April 2004, with nine Rasa Aragonesa rams. Ejaculates obtained every 2 days were pooled and used for each assay, to avoid individual differences, and three two-dimensional SDS-PAGE gels were run for each month. The high resolution of the gradient gel allowed the image analysis software to detect around 252 protein spots, with pIs ranging from 4.2 to 7.6, and molecular weight (M(r)) from 12.5 to 83.9 kDa. Four protein spots (1, 2, 3 and 4) of low M(r) (15.1, 15.7, 15.9 and 21.0 kDa) and acidic pI (5.9, 5.3, 5.7 and 6.6), respectively, had the highest relative intensity in the SP map (11.2, 9.3, 4.7 and 7.7%, respectively). Spot 3 was more abundant (P<0.05) from May to December, and negatively correlated (P<0.05, r=-0.34) with sperm viability and concentration (P<0.05, r=0.36). Another 12 protein spots also had significant quantitative differences (P<0.05) along the year, and 17 protein spots, which correlated with some seminal quality parameter, did not show quantitative monthly changes. Western-blot analysis indicated that spots 1 and 2 reacted with the anti-P14 antibody, raised against the P14 band (approximate M(r) 14 kDa) of ram SP. This indicates that spots 1 and 2 are similar to RSP15 [Bergeron A, Villemure M, Lazure C, Manjunath P. Isolation and characterization of the major proteins of ram seminal plasma. Mol Reprod Dev 2005;71:461-70], bovine PDC-109 [Esch FS, Ling NC, Bohlen P, Ying S, Guillemin R. Primary structure of PDC-109, a major protein constituent of bovine seminal plasma. Biochem Biophys Res Commun 1983;113:861-7] (also called BSP A1/A2 [Manjunath P, Sairam MR. Purification and biochemical characterization of three major acidic proteins (BSP-A1, BSP-A2 and BSP-A3) from bovine seminal plasma. Biochem J 1987;241:685-92]) and goat GSP-14/15 kDa [Villemure M, Lazure C, Manjunath P. Isolation and characterization of gelatine-binding proteins from goat seminal plasma. Reprod Biol Endocrinol 2003;1:39], based on our previous results on the P14 amino acid sequence [Barrios B, Fernández-Juan M, Muiño-Blanco T, Cebrián-Pérez JA. Immunocytochemical localization and biochemical characterization of two seminal plasma proteins which protect ram spermatozoa against cold-shock. J Androl 2005;26:539-49].

BSP A1/A2-like proteins in ram seminal plasma

The objective of this study was to assess the protein profile of ovine seminal plasma using 2D-PAGE and verify if BSP A1/A2 are present in ovine seminal plasma. Seminal plasma was collected from three mature rams and pooled to eliminate individual differences. Seminal plasma samples were submitted to 2D-PAGE using 12% acrylamide gels. The image analysis software identified 21 protein spots on the air-dried gel, with molecular weight ranging from 15 to 115 kDa and pI 3.2 to 8.7. The most prominent spots were those <30 kDa. The most intensely stained spots were: 3 (18-19 kDa, pI 4.8-5.0), 5 (17-18 kDa, pI 5.0-5.2), 7 (15-16 kDa, pI 6.2-6.4), and 23 (105-108 kDa, pI 6.8-7.0). Three of these spots (spots 3, 5 and 7, respectively) accounted for 41.1% of the relative intensity of the spots of the gels, based on the intensity of the Comassie blue staining. Western blot analysis indicated that spots 3 and 5 were similar to BSP A1/A2 (16.5, pI 4.7-5.0 and 16 kDa, pI 4.9-5.2) identified in Manjunath's studies [Manjunath P, Sairam MR. Purification and biochimical characterization of three major acid proteins (BSP A1, BSP A2 and BSP A3) from bovine seminal plasma. Biochem J 7 (1987) 685-92.], based on the specific reaction of the polyclonal antibody to those spots.

Two-dimensional polyacrylamide gel electrophoresis of bovine seminal plasma proteins and their relation with semen freezability

The objective of this study was to evaluate the low weight (10-30 kDa) protein profile of bovine seminal plasma using two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and to determine if any of these proteins was associated with semen freezability. Seminal plasma was collected from 16 bulls of high or low semen freezability. Twelve protein spots were identified from the 2D gel (15%); six of these were present in all samples. Of the 12 proteins found, three spots, present in all samples, 3 (15-16 kDa), 5 (16-17 kDa), and 7 (10-12 kDa) had nonsignificant variation among bulls, regardless of their freezability classification. Four proteins were more abundant (P<0.05) in seminal plasma samples collected from bulls with high semen freezability than in samples of bulls with low semen freezability: the spots 3 (15-16 kDa, pI 4.7-5.2), 7 (11-12 kDa, pI 4.8-4.9), 11 (13-14 kDa, pI 4.0-4.5), and 23 (20-22 kDa, pI 4.8-5.2). On the other hand, spot 25 (25-26 kDa, pI 6.0-6.5) was more abundant (P<0.05) on seminal plasma samples from bulls with low semen freezability. The N-terminus sequence of protein 7 was identical to the acidic seminal fluid protein (aSFP). Protein 23 (after trypsin digestion) had structural similarity to bovine clusterin. We concluded that there were differences in the seminal plasma protein profile from bulls with low and high semen freezability; aSFP, clusterin, proteins 3 and 11 may be used as semen freezability markers; and protein 25 was related to low semen freezability.