Two-dimensional polyacrylamide gel electrophoresis map of bull seminal plasma proteins

Serine metabolism during differentiation of human iPSC-derived astrocytes

Astrocytes are essential players in development and functions, being particularly relevant as regulators of brain energy metabolism, ionic homeostasis and synaptic transmission. They are also the major source of l-serine in the brain, which is synthesized from the glycolytic intermediate 3-phosphoglycerate through the phosphorylated pathway. l-Serine is the precursor of the two main co-agonists of the N-methyl-d-aspartate receptor, glycine and d-serine. Strikingly, dysfunctions in both l- and d-serine metabolism are associated with neurological and psychiatric disorders. Here, we exploited a differentiation protocol, based on the generation of human mature astrocytes from neural stem cells, and investigated the modification of the proteomic and metabolomic profile during the differentiation process. We show that differentiated astrocytes are more similar to mature rather than to reactive ones, and that axogenesis and pyrimidine metabolism increase up to 30 days along with the folate cycle and sphingolipid metabolism. Consistent with the proliferation and cellular maturation processes that are taking place, also the intracellular levels of l-serine, glycine, threonine, l- and d-aspartate (which level is unexpectedly higher than that of d-serine) show the same biosynthetic time course. A significant utilization of l-serine from the medium is apparent while glycine is first consumed and then released with a peak at 30 days, parallel to its intracellular level. These results underline how metabolism changes during astrocyte differentiation, highlight that d-serine synthesis is restricted in differentiated astrocytes and provide a valuable model for developing potential novel therapeutic approaches to address brain diseases, especially the ones related to serine metabolism alterations.

Seminal Plasma Proteins Associated with The Fertility of Brahman Bulls in The Colombian Low Tropics

The sperm interacts with seminal plasma proteins during its transport through the female reproductive tract to reach the oocyte. Seminal plasma proteins have been associated as biomarkers of fertility in bovine males, while two-dimensional electrophoresis in polyacrylamide gels under denaturing conditions (2D-PAGE) is a useful technique for their separation, allowing their subsequent analysis with the aid of specialised software. Brahman bulls are known for their tolerance to tropical conditions such as low-quality pastures, high temperatures, and relative humidity as well as moderate resistance to infestations by parasites and insects. The present study describes the two-dimensional electrophoretic profiles of the seminal plasma proteins in the rainy and dry seasons, associating them with the fertility of Brahman bulls in the Colombian Orinoquía in a 90-days breeding season and a single-sire mating system (1 bull per 50 Brahman cows) with 60 consecutive days of rest. The fertility-related seminal plasma protein spots increased in the dry season. Likewise, a meaningful relationship was found between the protein spots that possibly coincide with the Binder of Sperm Proteins. It was also found that bulls with the highest percentages of pregnancy also had similarities in their 2D seminal plasma maps. We conclude that the seminal plasma protein profile of Brahman bulls raised in the Colombian low tropic changes between rainy and dry seasons, and such changes may influence the reproductive performance of those animals.

Mass spectrometry-based proteomic strategy for ecchymotic skin examination in forensic pathology

Mass spectrometry (MS)-based proteomics has recently attracted the attention from forensic pathologists. This work is the first report of the development of a shotgun bottom-up proteomic approach based on rapid protein extraction and nano-liquid chromatography/high-resolution mass spectrometry applied to full-thickness human skin for the differential analysis of normal and ecchymotic tissues to identify new biomarkers for bruise characterization and dating. We identified around 2000 proteins from each pooled extract. The method showed excellent precision on independent replicates, with Pearson correlation coefficients always higher than 95%. Glycophorin A, a known biomarker of vital wounds from immunochemical studies, was identified only in ecchymotic tissues, as confirmed by Western blotting analysis. This finding suggests that this protein can be used as a MS-detectable biomarker of wound vitality. By focusing on skin samples from individuals with known wound dating, besides Glycophorin A, other proteins differentially expressed in ecchymotic samples and dependant on wound age were identified, although further analysis on larger datasets are needed to validate these findings. This study paves the way for an in-depth investigation of the potential of MS-based techniques for wound examination in forensic pathology, overcoming the limitations of immunochemical assays.

Response to microplastic exposure: An exploration into the sea urchin immune cell proteome

It is now known that the Mediterranean Sea currently is one of the major hotspot for microplastics (MPs; < 5 mm) pollution and that the risks will be even more pronounced in the coming years. Thus, the in-depth study of the mechanisms underlying the MPs toxicity in key Mediterranean organisms, subjected to high anthropic pressures, has become a categorical imperative to pursue. Here, we explore for the first time the sea urchins immune cells profile combined to their proteome upon in vivo exposure (72 h) to different concentrations of polystyrene-microbeads (micro-PS) starting from relevant environmental concentrations (10, 50, 10³, 10⁴ MP/L). Every 24 h, immunological parameters were monitored. After 72 h, the abundance of MPs was examined in various organs and coelomocytes were collected for proteomic analysis based on a shotgun label free proteomic approach. While sea urchins treated with the lowest concentration tested (10 and 50 micro-PS/L) did not show the presence of micro-PS in any tissue, in the specimens exposed to the highest concentration (10³ and 10⁴ micro-PS) there was an internalisation of 9.75 ± 2.75 and 113.75 ± 34.5 MP/g, respectively. Proteomic analyses revealed that MPs exposure altered coelomocytes protein profile not only compared to the control group but also among the different micro-PS concentrations and these variations are micro-PS concentration dependent. The proteins exclusively expressed in the coelomocytes of specimens exposed to MPs are mainly metabolite interconversion enzymes, involved in cellular processes, indicating a severe alteration of the cellular metabolic pathways. Overall, these findings provide new insights on the mode of action of MPs in the sea urchin immune cells both at the molecular and cellular level.

Seminal plasma proteins and their relationship with percentage of morphologically normal sperm in 2-year-old Brahman (Bos indicus) bulls

The objective was to determine the relationship between seminal plasma proteins and sperm morphology in Bos indicus bulls of the Brahman breed. Fifty-six 24-month-old Australian Brahman bulls were electroejaculated and samples were examined to determine the percentage of morphologically normal sperm (PNS24) and the seminal plasma protein composition was identified and quantified by 2-D gel electrophoresis. The total integrated optical density of 152 seminal plasma protein spots (SPPs) across all gels was determined using the PDQuest software version 8.0 (Bio Rad, USA). Using a single regression mixed model with the density of individual spots as a covariate for PNS24, 17 SPPs were significantly associated with PNS24 (p<0.05). A multiple regression analyses of these SPPs, using three models; non-parametric Tree Model, Generalized Additive Model, and a step-wise selection method were conducted, and 6 SPPs could be used to predict PNS24; four SPPs had positive and two had negative association with PNS24. Together these spots explained 35% of the phenotypic variation in PNS24. Using mass spectrometry (MALDI-ToF and TripleToF-MS) the SPPs with positive relationship contained mainly apolipoprotein A-I (1310), protein DJ-1 and glutathione peroxidase 3 (2308), phosphoglycerate kinase 1 (6402) and apolipoprotein A-I and secretoglobin family 1D member (8008). The SPPs inversely associated with PNS24 were clusterin/seminal plasma protein A3 (1411) and epididymal secretory protein E1 (8108). This is the first comprehensive report on the association between seminal plasma protein composition in Bos indicus Brahman bulls and sperm morphology.

Two-dimensional polyacrylamide gel electrophoresis of Bali bull (Bos javanicus) seminal plasma proteins and their relationship with semen quality

The present study evaluated the relationship between Bali bull (Bos javanicus) seminal plasma proteins and different semen quality parameters. Semen samples from 10 mature Bali bulls were evaluated for conventional semen parameters (general motility, viability, and normal morphology), sperm functionality (acrosome reaction, sperm penetration rate, sperm penetration index), sperm kinetics (computer-assisted semen analysis parameters such as sperm velocity), and sperm morphology (acrosome and membrane integrity). Frozen-thawed semen with higher sperm motility, viability, acrosome integrity, and membrane integrity (P < 0.05) are consistently higher in acrosome reaction and sperm penetration assay. Three bulls showed the highest, four bulls displayed the medium, and the remaining three bulls showed the lowest for all sperm parameters and SPA. The proteome maps of seminal plasma from high-quality and low-quality Bali bulls were also established. Seminal plasma of both high-quality and low-quality Bali bulls was subjected to two-dimensional SDS-PAGE with isoelectric point ranged from 3 to 10 and molecular weight from 10 to 250 kDa. Approximately 116 spots were detected with Blue Silver stain, and of these spots, 29 were selected and identified by MALDI-TOF/TOF-MS/MS. A majority of the proteins visualized in the seminal plasma two-dimensional maps was successfully identified. An essential group of the identified spots represented binder of sperm 1 (BSP1), clusterin, spermadhesin, tissue inhibitor of metalloproteinases 2 (TIMP-2), and phospholipase A2 (PLA2). Other proteins found in high abundance included seminal ribonuclease, serum albumin, cationic trypsin, and peptide similar to β2 microglobulin. Thus, a reference map of Bali bull seminal plasma proteins has been generated for the very first time and can be used to relate protein pattern changes to physiopathologic events that may influence Bali bull reproductive performance.

A proteomic approach to identify seminal plasma proteins in roosters (Gallus gallus domesticus)

Considering the interest in avian semen processing and storage, the objective of this study was to identify the domestic fowl seminal plasma proteins using two-dimensional gel electrophoresis (2-DE) and mass spectrometry MS/MS. For three times in a 4-month period, seminal plasma was obtained from semen collected from four local male chickens (Gallus gallus domesticus) and prepared for two-dimensional polyacrylamide gel electrophoresis. A total of 83 spots were detected across all gels and analyzed by MALDI-TOF/TOF. Among these spots, 17 have been successfully identified. The most intensely stained spots were recognized as serum albumin, ovotransferrin, alpha-enolase, fatty acid binding protein, thioredoxin, trypsin inhibitor CITI-1 and gallinacin-9. From these proteins, two are characteristic of avian seminal plasma, the ovotransferrin and gallinacin-9, and one is specific of the Gallus species, the chicken trypsin inhibitor CITI-1.

A comprehensive proteome map of bovine cerebrospinal fluid

Cerebrospinal fluid (CSF) is considered as the most promising body fluid target for the discovery of biomarkers for early diagnosis of neurodegenerative diseases such as Creutzfeldt-Jakob disease in humans and bovine spongiform encephalopathy in cattle. For the recognition of disease-associated changes in bovine CSF protein patterns, a detailed knowledge of this proteome is a prerequisite. The absence of a high-resolution CSF proteome map prompted us to determine all bovine CSF protein spots that can be visualised on 2-D protein gels. Using state-of-the-art 2-DE technology for proteome mapping of bovine ante mortem CSF combined with sensitive fluorescent protein staining and MALDI-TOF/TOF MS for protein identification, a highly detailed 2-DE map of the bovine CSF proteome was established. Besides the proteins mapped by earlier studies, this map contains 66 different proteins, including 58 which were not annotated in bovine 2-DE CSF maps before.

Adición de proteínas del plasma seminal ovino durante la congelación del espermatozoide y efectos sobre su motilidad y viabilidad

Este estudio se adelantó para evaluar el efecto de la adición de proteínas del plasma seminal de cordero en la criopreservación sobre la motilidad e integridad de la membrana espermática, y los cambios en el perfil electroforético de las proteínas de la membrana espermática inducidos por la criopreservación. Se usaron eyaculados de ocho corderos adultos de la raza rasa aragonesa, se les determinó su viabilidad y motilidad espermáticas y posteriormente se sometieron a un procedimiento de congelación. Las proteínas se separaron por el método de electroforesis en geles de acrilamida en dos dimensiones. Se obtuvo un mejoramiento significativo (p < 0,05) en la calidad del semen congelado, cuando se adicionaron proteínas del plasma seminal. El análisis bidimensional comparativo entre el semen fresco y el congelado evidenció la pérdida de 8 puntos de proteína en el espermatozoide descongelado. La concentración de un punto de proteína de membrana espermática, de bajo peso molecular (punto 2), fue más alta (p < 0,05) en el espermatozoide descongelado al que se adicionaron proteínas del plasma seminal. Se encontraron correlaciones entre algunos puntos de proteína y la motilidad y viabilidad espermáticas, lo cual sugiere que pueden jugar papeles importantes en el mantenimiento de la integridad y funcionalidad del espermatozoide. Se puede concluir que la adición de proteínas del plasma seminal en la congelación mejora la integridad del espermatozoide descongelado, y que la criopreservación del semen de cordero produce variaciones en la composición de las proteínas de membrana.      

Characterization of bovine seminal plasma by proteomics

Previous investigations of bovine seminal plasma (BSP) have revealed the identities of the three major proteins, BSP-PDC109, BSP-A3 and BSP-30 kDa, which together constitute about half of the total protein, as well as about 30 of the minor proteins. Analyses of BSP by 2-DE have revealed about 250 protein spots, suggesting that much of the BSP proteome remains undescribed. In this study, BSP has been analyzed by 2-D LC-based and SDS-PAGE-based proteomic methods. Ninety-nine proteins were identified, including 49 minor proteins that have not previously been described in seminal plasma of any species.

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].

Serum protein pattern during cow pregnancy: Acute-phase proteins increase in the peripartum period

Serum collected in a time-course mode during the pregnancy of a group of heifers was analyzed by 2-DE under various experimental conditions to optimize resolution of all protein spots. Changes in the levels of some components were detected during the last phase of pregnancy and early postpartum. These included a decrease of alpha2-HS-glycoprotein, an increase of alpha1-antichymotrypsin and, with a much larger and more abrupt variation, of orosomucoid and haptoglobin. These findings associate the weeks preceding calving with an acute-phase reaction. Analysis of individual animal's sera by 1-DE demonstrated a higher level of orosomucoid in the sera of cows developing postpartum endometritis during the 2 wk after calving (i.e., in the course of the infection) but a lower level during the 2 wk before calving. This observation could represent an important tool for the prepartum detection of animals prone to develop postpartum endometritis and lead to a more accurate peripartum management of those animals.

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.

Mussel MAP, a major gonad-duct esterase-like protein, is released into sea water as a dual constituent of the seminal fluid and the spermatozoon

Our interest in the comparative analysis of male reproductive-tract esterases in different animal groups has led us to undertake a detailed study of the Mytilus galloprovincialis male-associated polypeptide (MAP) throughout the mussel gonad-duct tract and at spawning. The results of this work indicate that MAP is a major protein in M. galloprovincialis semen, with dual presence in both sperm cells and cell-free seminal fluid. Shortly after spawning, the released sperm mass is subdivided in diffused cloudy-like and thread-shaped 'clots', in which a soluble-phase MAP may persist as long as the clots keep their compact form. Additional experiments involving the incubation of spawned spermatozoa at increasing Triton X-100 concentrations demonstrated that MAP is also strongly associated with sperm cells. These results were further validated by immunofluorescent staining, which revealed that MAP is localized in the mid-piece region of spawned spermatozoa. This unexpected finding raises the possibility that MAP may play a role in sperm fertility in bivalves. Using whole-mount histology and micromanipulation techniques, we studied the structural patterning of the mantle gonad-duct network and assessed the sampling of luminal contents from the ducts. Of particular interest is the observation that MAP content in the luminal fluid increases from the lumen of the spermatogenic tubules to that of the collecting gonad ducts, where MAP is detected at a very high concentration. These high levels may lead to a significant presence of MAP in semen and consequently to a prolonged survival of sperm spawned at sea. In addition, data related to the potential structural similarity between mussel MAP and esterase S of the Drosophila virilis ejaculatory bulb are presented and discussed. Finally, we show that the 64kDa protein of human semen reveals positive cross-reactivity with antibodies directed against Mytilus MAP and Drosophila esterase S. Taken together, the results reveal mussel MAP as the only esterase-like protein described so far whose distribution in the gonad and semen can be specifically associated with maturation, transport, emission and survival of spermatozoa outside.

Purification and primary structure of a new bovine spermadhesin

Z13 is a new seminal plasma protein made up of two disulfide-linked 13-kDa subunits that was identified in our laboratory by 2D PAGE. In this report we present the purification of Z13 from bovine seminal plasma. In solution, the protein is a nonglycosylated dimer that presents one interchain disulfide bond and does not show heparin-binding properties. The complete primary structure and the localization of the S-S bridges are reported. The results suggest that Z13 is a new protein of the spermadhesin family whose members are thought to play a prominent role in different aspects of fertilization.