Biophysical Modeling of the Ionizing Radiation Influence on Cells Using the Stochastic (Monte Carlo) and Deterministic (Analytical) Approaches.

This review article describes our simplified biophysical model for the response of a group of cells to ionizing radiation. The model, which is a product of 10 years of studies, acts as (a) a comprehensive stochastic approach based on the Monte Carlo simulation with a probability tree and (b) the thereof derived detailed deterministic models describing the selected biophysical and radiobiological phenomena in an analytical manner. Specifically, the presented model describes effects such as the risk of neoplastic transformation of cells relative to the absorbed radiation dose, the dynamics of tumor development, the priming dose effect (also called the Raper-Yonezawa effect) based on the introduced adaptive response approach, and the bystander effect. The model is also modifiable depending on users' potential needs.

Influence of the Season and Region Factor on Phosphoproteome of Stallion Epididymal Sperm.

Epididymal maturation can be defined as a scope of changes occurring during epididymal transit that prepare spermatozoa to undergo capacitation. One of the most common post-translational modifications involved in the sperm maturation process and their ability to fertilise an oocyte is the phosphorylation of sperm proteins. The aim of this study was to compare tyrosine, serine, and threonine phosphorylation patterns of sperm proteins isolated from three subsequent segments of the stallion epididymis, during and out of the breeding season. Intensities of phosphorylation signals and phosphoproteins profiles varied in consecutive regions of the epididymis. However, significant differences in the phosphorylation status were demonstrated in case of endoplasmic reticulum chaperone BiP (75 and 32 kDa), protein disulfide-isomerase A3 (50 kDa), nesprin-1 (23 kDa), peroxiredoxin-5 (17 kDa), and protein bicaudal D homolog (15 kDa) for season x type of phosphorylated residues variables. Significant differences in the phosphorylation status were also demonstrated in case of endoplasmic reticulum chaperone BiP and albumin (61 kDa), protein disulfide-isomerase A3 (50 kDa), and protein bicaudal D homolog (15 kDa) for region x type of phosphorylated residues variables.

The activity of N-acetyl-ß-hexosaminidase in boar seminal plasma is linked with semen quality and its suitability for cryopreservation.

The determination of sperm cryotolerance is an important step in the process of developing optimal techniques for the storage of boar semen. The objective of this study was to determine individual proteome variations in boar seminal plasma and spermatozoa and establish their influence on the cryotolerance of ejaculate. Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed the presence of protein with estimated molecular weight of 90 kDa in sperm extracts from ejaculates of selected boars. In all cases, dialysis performed at the initial stage of cryopreservation effectively removed the protein from sperm cells. The protein had an affinity for Zn(2+) ions. Mass spectrometry revealed similarities between the discussed protein and the ß subunit of N-acetyl-ß-hexosaminidase (ß-HEX). Seminal plasma ß-HEX was purified 252-fold with approximately 27% recovery and specific activity of 1800 U/mg of protein. Enzyme activity in fresh seminal plasma was correlated with superoxide dismutase activity (r = -0.42, P < 0.05), glutathione peroxidase activity (r = -0.42, P < 0.05), mitochondrial function (r = 0.31, P < 0.05), glutathione content (r = 0.34, P < 0.05), total protein content (r = 0.42, P < 0.05), and total oxidant status of seminal plasma (r = 0.37, P < 0.05). After thawing, ß-HEX activity in seminal plasma was negatively correlated with the total motile sperm count (r = -0.33, P < 0.05), plasma membrane integrity (r = -0.31, P < 0.05), and lipid peroxidation (r = 0.33, P < 0.05). The observed correlations indicate that lower levels of ß-HEX activity in boar seminal plasma are linked with higher quality of sperm after thawing. Based on those observations, the ejaculates were divided into two groups characterized by low (<20,000 U/L) and high (>20,000 U/L) levels of ß-HEX activity in seminal plasma. In plasma with high ß-HEX activity, spermatozoa were characterized by lower plasma membrane integrity (84.7%, P < 0.05). Higher glutathione levels (1250.3 µM), higher total protein content (50 mg/mL), and higher total oxidant status (6.82-µmol H2O2 Equiv/L) were also observed (P < 0.05). After thawing, lower sperm motility (20.4%), lower plasma membrane integrity (41.7%), and higher lipid peroxidation (30.9-nM malondialdehyde/10(8) spermatozoa/h) were reported in ejaculates with high seminal plasma ß-HEX activity. The results of this study indicate that ß-HEX activity in seminal plasma is a useful indicator in preliminary evaluations of boar sperm cryotolerance.

Superoxide dismutase (SOD) in boar spermatozoa: purification, biochemical properties and changes in activity during semen storage (16°C) in different extenders.

The antioxidant system in semen is composed of enzymes, low-molecular weight antioxidants and seminal plasma proteins. Loss of enzymatic activity of superoxide dismutase (SOD) during semen preservation may cause insufficient antioxidant defense of boar spermatozoa. The aim of this study was to isolate and characterize SOD molecular forms from spermatozoa and to describe changes in SOD activity in boar sperm during preservation at 16°C. Sperm extracts were prepared from fresh or diluted semen and used for SOD purification or activity measurement. Ion-exchange chromatography and gel filtration was used to purify SOD molecular forms. BTS, Dilu Cell, M III and Vitasem were used as diluents for 5-day storage of semen at +16°C. The molecular form of SOD released from spermatozoa after cold shock and homogenization had a molecular weight of approximately 67kDa. The activity of the SOD form was the highest at pH 10 within the temperature range between 20 and 45°C. The enzymatic activity of form released after cold shock was inhibited by H2O2 and diethyldithiocarbamate (DDC; by 65 and 40%, respectively). The SOD form released by homogenization was inhibited by H2O2 and DDC (40%). The molecular form released after urea treatment was a 30kDa protein with maximum activity at 20°C and pH 10. Enzymatic activity of this form was inhibited by H2O2 by 35%, DDC by 80% and 2-mercaptoethanol by 15%. The antigenic determinants of SOD isolated from boar seminal plasma and spermatozoa were similar to each other. Susceptibility of spermatozoa to cold shock increased during storage, but the differences between extenders were statistically non-significant.

Zinc-binding proteins from boar seminal plasma -- isolation, biochemical characteristics and influence on spermatozoa stored at 4°C.

Affinity chromatography on Chelating Sepharose Fast Flow Gel-Zn(2+) was used for fractionation of boar seminal plasma proteins. Approximately 30% of total boar seminal plasma proteins showed affinity for zinc ions (ZnBP fraction). Native electrophoresis (PAGE) of ZnBP revealed six protein fractions which separated into 27 bands under denaturing conditions (SDS/PAGE). Two-dimensional electrophoresis (2D PAGE) showed 148 polypeptides with isoelectric points mostly in the basic and neutral pH range. The zinc-binding proteins comprise mainly 10-20 kDa polypeptides which are probably members of the spermadhesin family. ZnBP present in the incubation mixture of spermatozoa stored for 1 or 24 h at 4 °C allowed preservation of a higher percentage of cells exhibiting linear motility in comparison to a control sample stored in PBS. Presented results indicate that proteins binding Zn(2+) ions have a shielding effect on the sperm plasma membrane and acrosome of spermatozoa, protecting these structures against consequences of cold shock.

High sequence homology between protein tyrosine acid phosphatase from boar seminal vesicles and human prostatic acid phosphatase.

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.

Application of biochemical markers for identification of biological properties of animal semen.

The use of biochemical markers for identification of biological properties of semen will help to develop new criteria that are accurate and objective in predicting and improving male fertility. Understanding and controlling the mechanisms involved in fertility is a key challenge, which is of fundamental importance in successful animal reproductive performance. Moreover, unraveling the unique molecular mechanism associated with sperm function might have considerable diagnostic value in the evaluation of male infertility. This review offered insights into some recent achievements and provided perspectives for possible applications of the biochemical markers of semen.

Proteomics of boar seminal plasma - current studies and possibility of their application in biotechnology of animal reproduction.

Proteomics is critical to identify the properties and functions of proteins involved in the mechanism regulating the male reproductive tract function. This approach is important in male fertility assessment and clinical diagnosis of the physiological state of individual reproductive organs. Proteomics also provides a tool to understand the interactions of seminal plasma proteins with spermatozoa, which could provide a useful model for studying ligand-cell interaction occurring at the sperm cell surface. This review covers a selection of advances in the realm of functional proteomics of boar seminal plasma proteins and is focused on some fundamental proteomic technologies. Also, this review explores key themes in proteomics and their application in animal reproductive techniques.