National Repository of Grey Literature 2 records found  Search took 0.01 seconds. 
Effect of sperm ubiquitination on the early embryonic development in pig
Kroumanová, Kristýna ; Krylov, Vladimír (advisor) ; Nevoral, Jan (referee)
The ubiquitin-proteasomal system which is the major pathway for intracellular protein degradation is also involved in sperm quality control in the mammalian epididymis. Defective sperm become surface- ubiquitinated during epididymal passage. The level of sperm surface ubiquitination negatively correlates with their quality. Hypothetically it is possible that after fertilization, highly ubiquitinated sperm, naturally present in mammalian ejaculates, would be actively recognized by oocyte (probably via 26S proteasomal complex). Subsequent partial or total sperm degradation should negatively affect the development of the potentially defective embryo. In this study, we examined the effect of sperm ubiquitination on the early embryonic development in pig (Sus scrofa f. domestica) using the method of intracytoplasmic sperm injection (ICSI). In vitro embryonic development to the blastocyst stage after ICSI was comparable with other laboratories. In this study, no significant difference was observed in the formation of pronuclei between oocytes fertilized by lower and highly ubiquitinated sperm cells. On the other hand, significantly better embryonic development to the blastocyst stage was observed in oocytes fertilized by sperm with lower surface ubiquitination (17 %) compared with oocytes fertilized by highly...
Effect of ubiquitin-proteasome system on spermiogenesis in mammals
Kroumanová, Kristýna ; Petelák, Aleš (advisor) ; Krejčová, Tereza (referee)
Spermiogenesis is a complicated process in which the haploid spermatids differentiate into morphologically mature sperm. Morphological changes include condensation of chromatin and histone-to-protamine replacement, fusion of Golgi-derived vesicles to form acrosomal cap, flagellum formation, reduction of cytoplasmic volume and organelles rearrangement. Ubiquitin-proteasome system plays a key role in these processes. Ubiquitination is a posttranslational modification, leading to the labelling of intracellular proteins targeted for degradation by 26S proteasome. Importance of sperm ubiquitination, is supported by the fact, that deficiency of ubiquitin-proteasome system can lead to infertility at various degrees. During the subsequent sperm maturation in the epididymis extracellular ubiquitination of abnormal sperm and sperm quality control take place. Ubiquitin-proteasome system plays a key role during fertilization, when the sperm 26S proteasome is co-responsible in zona pellucida penetration. The purpose of this assay is to describe the effect of ubiquitin- proteasome system during different stages of spermiogenesis in mammals.

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