Piotr Pawlak

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The developmental competence (quality) of oocytes is affected by several factors linked to their intrinsic properties and also to growth and maturation environment. Donor puberty and chromosomal complement are one of the main factors influencing oocyte quality. A high rate of porcine oocytes matured in vitro is chromosomally imbalanced. Moreover, there is(More)
Three Sus scrofa Piwi genes (Piwil1, Piwil2 and Piwil4) encoding proteins of 861, 985 and 853 aminoacids, respectively, were cloned and sequenced. Alignment of the Piwi proteins showed the high identity between Sus scrofa and Homo sapiens. Relative transcript abundance of porcine Piwil1, Piwil2 and Piwil4 genes in testes, ovaries and oocytes derived from(More)
Preimplantation bovine development is emerging as an attractive experimental model, yet little is known about the mechanisms underlying trophoblast (TE)/inner cell mass (ICM) segregation in cattle. To gain an insight into these processes we have studied protein and mRNA distribution during the crucial stages of bovine development. Protein distribution of(More)
Although differences in the quality of oocytes derived from young gilts and adult sows are well documented, evidence concerning gametes of pre-pubertal and cycling gilts is scarce and inconsistent. The aim of this work was to establish whether sexual maturity of gilts affects the quality of their oocytes with the use of the brilliant cresyl blue (BCB) test,(More)
The objective of this study was to evaluate selected aspects of cytoplasmic maturation in oocytes from prepubertal and cyclic crossbred gilts before and after in vitro maturation. For this purpose, cortical granule redistribution, mitochondrial DNA content and mitochondria translocation were analyzed. Moreover, for the first time the fatty acid profiles in(More)
The oocyte quality is to a large extent influenced by the sexual maturity of the donor female. Although this phenomenon has already been broadly described in domestic animals, the underlying mechanisms are poorly understood. Published data focus on oocyte ultrastructure, fertilization abnormalities, and blastocyst developmental rate. The goal of the present(More)
Embryo quality related to its developmental potential is now one of the most important issues in modern embryology. It has been demonstrated that some in vitro produced blastocysts fail to hatch and implant after transfer despite a normal morphology. Although embryos are able to adjust to sub-optimal culture conditions, significant changes in expression(More)
Environmental stress often leads to an increased production of reactive oxygen species that are involved in plastid-to-nucleus retrograde signaling. Soon after the release of singlet oxygen ((1)O(2)) in chloroplasts of the flu mutant of Arabidopsis, reprogramming of nuclear gene expression reveals a rapid transfer of signals from the plastid to the nucleus.(More)
Great progress has been achieved over the last years in studies on chromosome arrangement in mammalian cell nuclei. Growing evidence indicates that the genome's spatial organization is of functional relevance. So far, no attention has been paid to the nuclear organization of B chromosomes (Bs). In this study we have examined nuclear positioning of Bs in 2(More)
The present study aimed to investigate whether the timing of the first zygotic cleavage (FZC) influences the speed of embryo development expressed by the total cell count and the rate of chromosomally aberrant embryos. Bovine embryos were produced in vitro and divided into two categories according to the timing of FZC: early cleavers (at 30 hpi; EC) and(More)