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Zinc-binding proteins from seminal plasma (ZnBPs) originate in the secretions of different accessory sex glands and are implicated in key events associated with sperm-egg fertilization processes. This study describes the isolation and characterization of the ZnBPs of canine seminal plasma. Ejaculates were collected from three crossbred dogs for a 2-week period. The ZnBPs as well as non zinc-binding proteins (nZnBPs) were isolated by zinc-dependent affinity chromatography. The isolated fractions were subjected to native gel electrophoresis (one-dimensional polyacryamide gel electrophoresis, PAGE) and sodium dodecyl sulphate polyacryamide gel electrophoresis (SDS-PAGE), using denaturing and reducing conditions. Zinc-elution profile using affinity chromatography displayed two protein fractions represented by the nZnBPs and ZnBPs, respectively. Using native gel electrophoresis, it was found that both the nZnBPs and ZnBPs occurred in their native state as aggregates, ranging from 140 to 669 kDa. The nZnBPs were disaggregated into 8 protein bands, with molecular weights ranging from 10.7 to 79.7 kDa, following SDS-PAGE analysis. By contrast, SDS-PAGE analysis of the ZnBPs revealed 13 protein bands, with molecular weights ranging from 11.6 to 152.3 kDa. Densitometric analysis showed that 46-48% of nZnBPs could be accounted by protein fractions with molecular weights of 10.7 and 14.2 kDa. Also, 2 protein fractions with molecular weights of 11.6 and 14.3 kDa, were predominant in ZnBPs, accounting for approximately 28-30% of the total proteins. These results demonstrate the zinc-binding capacity of proteins secreted by the canine prostate. The findings of this study indicate that ZnBPs of canine seminal plasma comprise several protein fractions, which might be implicated in the reproductive processes in the dog.
Two-dimensional electrophoresis (2-D PAGE) led to identification in the polypeptide maps of boar seminal plasma of four conserved polypeptides with identical molecular weight of 24 kDA, and different ranges of isoelectric point (pI): (1) 7.4-7.7, (2) 8.1-8.4, (3) 8.5-8.8 and (4) 9.2-9.4. In the current study the molecular structures of these polypeptides were analysed, for the first time, by mass spectrometry (LC – MS/MS). Computerized mass spectrometry analysis of the peptides obtained after trypsin-digestion of the polypeptides demonstrated their similarity to the family of spermadhesins (crystal structure of two members of the spermadhesin family), especially to epididymal spermadhesin AWN-1. In addition, homology was found of peptides 3 and 4 with a lysozyme C precursor (1,4-beta-N-acetylmuramidase C). The results presented might indicate the participation of the analysed polypeptides in the processes accompanying fertilization.
Zinc-binding proteins (ZnBPs) isolated from boar seminal plasma exert multiple effects on boar spermatozoa. The aim of this study was to determine whether the isolated zinc-binding proteins were capable of binding additional ligands. The affinity chromatography method was used for the first time to demonstrate that boar ZnBPs show affinity for both heparin (hep) and phosphorylcholine (pch). ZnBPs+hep accounted for approximately 20%, and ZnBPs+pch – for approximately 45% of total ZnBPs. Predominant polypeptides with molecular mass form 6.5 to 14 kDa were observed in both groups (ZnBPs+hep, ZnBPs+pch). The analyzed peptides’ low molecular mass and their ability to bind zinc ions as well as heparin and phosphorylcholine suggest that they belong to the family of multifunctional boar spermadhesins which perform their functions in the fertilization process by binding more than one ligand. The results indicate that the ZnBPs of boar seminal plasma may be involved in the processes associated with oocyte fertilization not only by zinc ions binding but also through heparin and phosphorylcholine.
 In this study immunoelectrophoretic and double immunodiffusion analyses were used to investigate the antigenic character of zinc-binding proteins (ZnBPs), whereas the indirect immunofluorescence technique was used to identify their origin in boar reproductive tract. The mmunoelectrophoretic analysis of ZnBPs of the seminal plasma resulted in the appearance of three antigenic protein complexes, while specific immunoreactivity patterns of the anti-ZnBP serum were detected by double immunodiffusion analysis. Indirect immunofluorescence technique confirmed that ZnBPs were secreted by different reproductive tract tissues, suggesting their contributions to the seminal plasma.
The study has revealed the presence of fibronectin (FN) fragments and a lack of intact FN in 72 seminal plasma samples. The FN fragmentation was examined by immunoblotting with a monoclonal antibody specific to the central cellular FN domain and was confirmed with a monoclonal antibody directed to the C-terminal domain of FN. Nine FN fragments between 60 and 200 kDa and five fragments of 60–150 kDa were identified in seminal plasma samples of normozoospermic and of terato-, oligoterato-, and oligoasthenoterato-spermic groups, respectively. The relative amounts of the 60, 90 and 100 kDa FN fragments were 2–3 times higher in seminal plasmas with abnormal semen characteristics than in the normozoospermic group. The results suggest that seminal plasma FN fragments may contribute to fertilization and the analysis of FN fragmentation may have a diagnostic value in andrological investigations.
The N-terminal amino acid sequence was analysed of 43 kDa polypeptide, component of the protein complex of PAF acetylhydrolase (PAF-AH) isolated from boar seminal plasma. Amino acid sequence of the 43 kDa did not show homology with the characteristic sequences of PAFAH isolated from other sources. However, 43 kDa showed a high homology with the characteristic sequences of IgG-binding proteins as well as with zona pellucida-binding adhesion proteins - zonadhesions. The results indicate that the isolated 43 kDa polypepfide belongs to the family of adhesion proteins, involved in the processes accompanying egg fertilization.
The influence of ß-haemolytic Streptococcus organisms at concentrations of 100 x, 200 x, and 500 x 10³ cells/ml sperm incubated at 37°C for 60 min with stallion semen suspension on the motility, viability and morphology of the semen, and AspAT activity in seminal plasma was examined. S. zooepidemicus at a concentration of 500 x 10³ cells/ml exhibited a particularly unfavourable effect on semen. All parameters measured altered significantly after a 60 min incubation. The activity of AspAT also changed during a prolonged incubation of sperm with a suspension containing 500 x 10³ S. zooepidemicus/ml semen; after a 24 h incubation the activity of AspAT was enhanced by more than 38% in comparison to the initial value.
Boar seminal vesicle protein tyrosine acid phosphatase (PTAP) and human prostatic acid phosphatase (PAP) show high affinity for protein phosphotyrosine residues. The physico-chemical and kinetic properties of the boar and human enzymes are different. The main objective of this study was to establish the nucleotide sequence of cDNA encoding boar PTAP and compare it with that of human PAP cDNA. Also, the amino-acid sequence of boar PTAP was compared with the sequence of human PAP. PTAP was isolated from boar seminal vesicle fluid and sequenced. cDNA to boar seminal vesicle RNA was synthesized, amplified by PCR, cloned in E. coli and sequenced. The obtained N-terminal amino-acid sequence of boar PTAP showed 92% identity with the N-terminal amino-acid sequence of human PAP. The determined sequence of a 354 bp nucleotide fragment (GenBank accession number: GQ184596) showed 90% identity with the corresponding sequence of human PAP. On the basis of this sequence a 118 amino acid fragment of boar PTAP was predicted. This fragment showed 89% identity with the corresponding fragment of human PAP and had a similar hydropathy profile. The compared sequences differ in terms of their isoelectric points and amino-acid composition. This may explain the differences in substrate specificity and inhibitor resistance of boar PTAP and human PAP.
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