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1

Transvaginal method of bovine oocytes collection: aspiration efficiency, developmental competence of oocytes and application in breeding

100%
Smorag Z., Gogol P., Kuznetsov V.
Biotechnologia
|
1998
|
issue 2
153-160
EN
This paper describes the ultrasound-guided transvaginal method of oocyte collection in cattle. Both technical and physiological aspects affecting the efficiency of the method are presented. The results of the author's experiments on oocytes collection and their developmental competence is also discussed.
2

Characterization of mammalian oocyte competence to undergo fertilization and embryonic development: II. Regulation of cytoplasmic and genomic maturation

80%
Opiela J., Katska-Ksiazkiewicz L.
Biotechnologia
|
2005
|
issue 2
151-162
EN
Near the end of the growth phase, mammalian oocyte achieves competence to undergo three aspects of maturation, i.e. nuclear, cytoplasmic and genomic. This review will consider some aspects of cytoplasmic and genomic maturation, as the nuclear maturation was already presented. The roles of the protein synthesis, bi-directional communication between oocyte and granulosa cells and calcium oscillations required for acquiring cytoplasmic maturation are discussed. The relevant information on genomic imprinting that causes functional differences between paternal and maternal genomes and plays an essential role in mammalian development is reviewed. Moreover, the present findings regarding oocyte-specific genes required for expression of cytoplasmic and genomic competencies are described.
3

Morphology and developmental potential of bovine parthenotes after spontaneous activation in vitro

80%
Lechniak D., Cieslak D., Sosnowski J.
Journal of Applied Genetics
|
1998
|
vol. 39
|
issue 2
193-198
EN
Spontaneous parthenogenetic activation of bovine oocytes in an in vitro maturation and fertilization system (IVM/IVF) is described. Altogether, 1403 follicular oocytes, collected by the aspiration method, were matured in vitro and then cultured without insemination in the same conditions as a group of inseminated oocytes. After 48-72 h of additional culture, 141 oocytes (10%) were found to be spontaneously activated. Morphological evaluation revealed that the number of blastomeres within parthenotes ranged from 2 to 16 cells, with a minority (15.7%) comprising of 9-16 blastomeres. According to a cytogenetic analysis, only 1.2% of the analysed parthenotes consisted of more than 9 cells. Parthenotes may not be distinguished from embryos produced in vitro and spontaneous parthenogenetic activation in an IVM/IVF system indicates suboptimal culture conditions. A group of non-inseminated oocytes should be included in each experiment to serve as a control. Spontaneously activated bovine parthenotes only occasionaly developed beyond the 8-blastomere stage in a common IVM/IVF system. The incidence of parthenotes interferes with the efficiency of in vitro embryo production but it is doubtful whether it lowers the pregnancy rate after transfer of IVF embryos.
4

Analysis of oocyte quality in recombinant inbred mouse strains developed from KE and CBA strains that differ in fertilization efficiency

80%
Wabik-Sliz B., Golas A., Krzanowska H.
Journal of Applied Genetics
|
2005
|
vol. 46
|
issue 2
163-170
EN
Recombinant inbred (RI) mouse strains were developed from reciprocal crosses between two inbred strains differing in the proportion of fertilized ova (CBA, 100%; KE, 77%), to analyse the underlying factors. A correlation (r = 0.83, P < 0.01) between fertilization efficiency within 22 RI strains and after mating RI females with KE males proved that oocyte quality was involved. The following oocyte parameters were analysed in RI and progenitor strains: time of meiotic maturation, rapidity of enzymatic removal of egg investments, and proportion of fertilized ova with supplementary spermatozoa in the perivitelline space. Among the RI strains, high incidence of supplementary spermatozoa was correlated with lower efficiency of fertilization (r = ?0.58, P < 0.05) and with slow meiotic maturation (r = ?64, P < 0.01), suggesting that delayed maturation may affect oocyte ability of being fertilized by the first penetrating spermatozoon. However, significant correlations were also found between characters which coexist within the progenitor strains, but are not likely to be physiologically related; this suggests that RI strains have inherited large blocks of progenitor genomes, not disrupted by recombination. The strain distribution pattern (SDP) of the analysed traits revealed CBA-like, KE-like, and intermediate phenotypes, indicating that they are polygenically determined. No linkages were found between the studied traits and 12 enzymatic markers. However, the SDP for fertilization efficiency showed a preponderance of non-matching strains (15/19) in relation to agouti locus; the known instability of this chromosome region makes it possible that a putative linkage was disrupted by recombination when RI strains were created.
5

Optimalization of fluorescence in situ hybridization conditions in mare oocytes and mouse embryos

80%
Bugno M., Jablonska Z., Slota E.
|
2009
|
vol. 57
|
issue 1-2
49-55
EN
The aim of the study was to optimize hybridization conditions of molecular probes specific for X sex chromosomes of the domestic horse in mare oocyte chromosomes. Mare oocytes, recovered from slaughterhouse ovaries by scraping the granulosa layer, were cultured in vitro. Metaphase II mature oocytes were treated with hypotonic solution and fixed, followed by hybridization of themolecular probe specific for the X chromosome of the domestic horse. Hybridization of probes specific formouse heterosomes onmouse oocytes and early embryos was performed to verify the FISH technique. Of 438 oocytes analysed, 29% reached metaphase II. Despite many changes in the composition of hypotonic solutions and modification of the FISH protocol, the fluorescence signal was observed in mouse oocytes and embryos but not in mare oocytes.
6

Long-term culture preantral and early antral ovarian follicles in mammals- perspectives and recent development

80%
Katska-Ksiazkiewicz L.
|
2003
|
issue 1
129-137
EN
The ovary of mammal contains thousands of oocytes enclosed in the preantral and early antral follicles. Since more than 99% of ovarian oocytes undergo atresia, it would be of great practical benefit if these follicles could be rescued by a long-term in vitro culture leading to provide an additional source of gametes and allowing for more efficient improvement of the reproductive potential of female. Until now, research on the isolated preantral follicles are the best developed in rodents. In mouse, investigations have led to follicle growth and antrum formation, ovulation in vitro and even to a few live kids after in vitro maturation and fertilization of the oocytes recovered from in vitro cultured preantral and even primordial follicles. Recently, some progress in the development of methods that allow obtaining competent oocytes and, after IVF, even blastocysts was shown in farm animals. However, only follicles with selected size can be utilized for these purposes. The successful results are encouraging for further development of methods for culture of preantral follicles in farm animals. In the article, techniques of follicle recovery, in vitro culture systems, methods for evaluation of oocyte growth, quality and competence for maturity and IVF including our impact in development of presented methods are discussed.
7

Apoptosis in oogenesis and preimplantation embryo development of mammals

80%
Warzych E., Lechniak D.
Biotechnologia
|
2005
|
issue 1
172-182
EN
In this paper, the authors made an attempt to summarize the present knowledge on apoptosis in mammalian oocytes and embryos. On the contrary to necrosis, apoptosis is a programmed death of damaged or mutated cells. Several studies showed that it takes place during oogenesis (oocyte growth and maturation), as well as at some stages of preimplantation embryo development (morula, blastocyst). Although apoptosis is observed in vivo, the frequency of this phenomenon increases in vitro. There is a number of methods detecting apoptotic cells, however, none of them gives a clear evaluation of the studied process. A complex analysis with the use of several methods is therefore advised. Because in ovary the majority of oocytes undergo atresia (over 99%), the scientists concentrate on developing new methods aiming at improvement of females' reproductive performance. The process of apoptosis seems to be a crucial limiting factor.
8

Cryoconservation of mammalian embryos and oocytes

80%
Gajda B., Smorag Z.
Biotechnologia
|
1998
|
issue 2
10-33
EN
This paper presents current methods of embryo and oocyte cryoconservation in the following species: mice, rabbits, sheep and goats, pigs, horses and cows. Both the freezing and vitrification methods are discussed with special emphasis on the major factors affecting the efficiency of these two methods.
9

In vitro embryo production in cattle ? technology and practical application

80%
Katska-Ksiazkiewicz L.
Biotechnologia
|
2004
|
issue 1
32-42
EN
Technology of bovine in vitro embryo production (IVP) had developed during the last few years to the level which allows its practical applications. Recently, IVP technology has been commercially used in several countries to increase the number of calves originating from donors of high genetic value. Combined with ovum pick-up technique (OPU), IVP technology serves as en alternative or integral method in breeding program MOET. The technology of IVP includes three developmental steps, i.e. oocyte in vitro maturation, in vitro fertilization and embryo culture. This review will focus on immature bovine oocyte recovery and selection, in vitro maturation, sperm processing, embryo culture to hatched blastocysts stage and factors affecting IVF efficiency. Moreover, recently developed investigations (IVP using calf oocytes and oocytes originating from small ovarian follicles) aiming to increase the effectiveness of IVP technology are discussed as well.
10

Maturation and activation of porcine oocytes in the aspect of fertilization and somatic cell cloning ? biochemical, molecular and biophysical determinants

70%
Samiec M.
Biotechnologia
|
2009
|
issue 3
59-84
EN
The commonly used source of nuclear recipient cells in the somatic cell cloning of pigs are in vivo-matured (ovulated) or in vitro ? matured oocytes, reversibly blocked at the second metaphase (MII) stage. One of the most important factors that significantly affect the developmental competences of porcine cloned embryos is the artificial activation of oocytes reconstructed with somatic cell nuclei. The ability of an artificial stimulus to activate MII-stage oocytes and to initiate embryo development is essential for successfull cloning by somatic cell nuclear transfer. This ability is especially important for species such as the pig where relatively little is known about early embryonic development and where in vitro handling procedures have not been optimized. An optimal time frame to activate gilt or sow oocytes may depend on both the time required for completion of nuclear-cytoplasmic maturation and the time by which aging process of mature oocytes starts. Cytoplasmic maturation is likely to include changes in the properties, size, and density of cytoplasmic Ca2+ release channels necessary for the oocyte to elicit an increase in intracellular Ca2+ concentration in response to the activating stimuli and subsequent development. Activation of oocytes, which has been induced either during fertilization or by artificial agents during the cloning procedure, evokes the cytosolic calcium concentration ([Ca2+]c) oscilations or single [Ca2+]c transients. Despite the uncertainty of how the initial rises in [Ca2+]c are prompted, it is widely accepted that physiological or artificial activation stimulates the phosphoinositide pathway, with the generation of myo-inositol-1,4,5-trisphosphate (InsP3) by the enzymatic action of phospholipase C (PLC), and the subsequent release of calcium cations from endoplasmic reticulum. Further investigation in nto the role of PLC isoforms as the triggers of [Ca2+]c increases has led to the recent identification of a sperm-specific PLC (PLC-ksi) as the putative sperm-derived oocyte activating factor. It is known that InsP3-mediated calcium signaling pathway is responsible for downregulation of maturation-promoting factor (MPF), which contributes to such events during oocyte activation as resumption and termination of meiosis, extrusion of the second polar body, pronuclear formation, transition from meiotic to mitotic control of cell cycle and initiation of embryonic cleavage.
11

Oogenesis in Vimba vimba (L. 1758) from Drawienski National Park (NW Poland)

70%
Hliwa P., Femska-Zakes K., Martyniak A., Krol J.
Folia Biologica
|
2003
|
vol. 51
|
issue 3-4
165-170
EN
The objective of the studies was to analyse the process of oogenesis in vimba from a non-migratory population living in the waters of Drawienski National Park in north-west Poland. The character of spawning of this species is an obstacle in determining the right moment to catch spawners or developing artificial spawning biotechniques. Previtellogenesis of vimba begins about six months after hatching and lasts three years. The trophoplasmatic growth of oocytes (October ? March/April) begins when carbohydrate vesicles appear near the nuclei oocytes of sexually mature females (aged 4+). Just before spawning, granulated, lipoprotein-like substances are cumulated. The resorption of pre-ovulation corpora lutea (non-ejected oocytes) and post-ovulation corpora lutea (ruptured theca folds and follicles) begins in the ovary of vimba in the middle of June. These were observed in histological cross sections for about two to three months. Describing the process of oogenesis can provide a foundation for developing practical applications in aquaculture aimed at preserving the biodiversity of the park?s waters and this critically endangered species of the Polish ichthyofauna.
12

Structure and development of ovaries in the weevil, Anthonomus pomorum (Coleoptera, Polyphaga). II. Germ cells of the trophic chamber

70%
Swiatek P.
|
|
issue 3-4
153-163
EN
The analysis of the germ cell cluster formation in Anthonomus pomorum (Coleoptera, Polyphaga, Curculionidae) has revealed that both linear and branched clones of cystocytes occur in the pupa stage. In the branched clones a poorly developed polyfusome is formed and cystocytes with maximally 3 intercellular bridges were found. In the linear clones the polyfusomes are absent. Further divisions of cystocytes produce exclusively linearly arranged cells. Just after metamorphosis (Imago-A stage), the process of the germ cell membrane reduction starts. Only 2 groups of cells retain cell membranes: i.e the most anteriorly localized group of cystocytes and the posteriorly located presumptive oocytes. The former cells divide mitotically during the summer. As a result an anterior-posterior gradient of the syncytialization process arises in the Imago-B stage (females preparing for hibernation). In the sexually mature females (Imago-C) the trophic chamber consists of a huge syncytial area with numerous nurse cell nuclei embedded in a common cytoplasm, and posteriorly located young oocytes surrounded by prefollicular cells. In the light of recent hypothesis concerning the germ cell cluster formation and telotrophy anagenesis in Polyphaga the significance of the presented results is discussed.
13

Ovariole development in telotrophic ovaries of snake flies (Raphidioptera)

70%
Jedrzejowska I., Kubrakiewicz J.
Folia Biologica
|
2004
|
vol. 52
|
issue 3-4
175-184
EN
Snake flies (Raphidioptera), alder flies (Megaloptera: Sialidae) and also some myxophagan coleopterans share the same, peculiar telotrophic organization of their ovarioles usually referred to as ovarioles of the Sialis-type. Ovariole ontogenesis in Raphidia sp. is described and the basic events that lead to the formation of germ cell clusters and their subsequent transformations are reported. It was found that the major cellular events during ovariole formation in Raphidia and Sialis are essentially the same. Discrepancies concern details of germ cell cluster formation, differentiation of cystocytes within clusters and their location within the developing tropharium. Based on these results the hypothetical model of the Sialis-type ovariole formation, previously presented by KING and BNING (1985) is verified. A hypothesis on the mechanisms of oocyte determination in telotrophic ovaries is also presented.
14

The application of in vitro cattle embryo production system to study the influence of elevated temperature on oocyte maturation, fertilization and early embryonic development

61%
Rynkowska A., Rapa?a L., Trzeciak P., Duszewska A. M.
Biotechnologia
|
2011
|
issue 1
45-53
EN
Higher air temperature in summer causes a significant reduction in fertility in cattle. Increase in female body temperature during the period of reproduction by only 2EC, also known as hyperthermia, leads to disturbances in the functioning of the female reproductive system, oocytes maturation, fertilization and embryos development. Particularly sensitive to high temperatures are embryos in the first and second day after fertilization (thermosensitive), but just at third till fifth day after fertilization their resistance to thermal stress significantly increases. Morula-stage and blastocyst-stage bovine embryos are insensitive to elevated temperatures (thermoresistant). Most probably this is due to the increasing number of cells within the embryo and the capacity to activate defense mechanisms based on the synthesis of various factors providing resistance to high temperatures. These factors include heat shock protein 70 (HSP70), antioxidants such as glutathione, and IGF-1. One of the responses of the embryo to elevated temperature is the induction of apoptosis, which is associated with the activation of embryonic genome. Owing to the apoptosis, cells damaged by high temperature may be eliminated from the embryo, which increases their chance of survival. Precise examination of the mechanisms responsible for the development of thermotolerance of preimplantation bovine embryos will enable their protection from the consequences of elevated temperature. The aim of this review is to summarise experiments in which in vitro embryo production system was used to estimate the influence of elevated temperature on cattle fertility.
15

The use of new strategies in the cloning studies on somatic cell cloning in pigs

61%
Skrzyszowska M., Samiec M.
Biotechnologia
|
2006
|
issue 1
68-81
EN
Somatic cell nuclear transfer (SCNT) technique in pigs remains relatively low (2% to 5% of produced piglets), that is why further efforts have to be made to optimize both a multi-step cloning procedure and to improve a structuro-functional quality of recipient oocytes and nuclear donor cells. Pre- and postimplantation developmental potential of porcine SCNT-derived embryos depends to a high degree on not only coordination of mitotic cycle stage with phenotype of nuclear donor cell, but also proper combination of the methods of maternal chromosome elimination (enucleation), oocyte reconstruction techniques, the systems of artificial activation of generated nuclear-cytoplasmic hybrids (clonal cybrids) and in vitro culture of reconstructed embryos. Generally, it can result in increasing the competences of both somatic nuclear and mitochondrial genome for epigenetic remodeling/reprogramming in developing cloned embryos.
16

Cryopreservation of porcine oocytes and embryos

61%
Gajda B., Smorag Z.
|
2003
|
issue 1
116-228
EN
This paper presents the current possibilities, state of knowledge and prospects for cryopreservation of pig oocytes and embryos. The main factors of cryopreservation efficiency, methods for the evaluation of cryopreserved embryos, and the possibilities of modifying their susceptibility to cryopreservation are discussed. In addition, the most significant results of pig embryo freezing and vitrification and the cryotechnical aspects of this method are presented.
17

Methods for obtaining in vitro oocytes and embryos in mammals - possibilities and limitatios

61%
Katska L.
Biotechnologia
|
1995
|
issue 3
33-43
EN
The autors discuss methods through which the reproductive potentialin cattle may be increased.Two procedures for mass production of embryos to be used in cattle breeding schemes are now available, namely superovulation and embryo transfer, nd more recently in vitro embryo production.Hormonal treatmentfor multiple ovulation, nonsurgical embryo collection and embryo transfer are widespread techniques to obtain more offspring from genetivally superor cattle (MOET program).However,the cost can br high and the yield of embryos is unpredictable.
18

Vitrification of mammalian oocytes and embryos

51%
Smorag Z., Gajda B.
Biotechnologia
|
1995
|
issue 3
68-83
EN
Vitrification is a new approach to oocyte and embryo cryoconservation.It consists in the solidification of a solution caused by draastic increase in viscosity during cooling and not by crystalization.The application of this approach to cryoconservation of oocytes and embryos of different species depends upon the development of proper procedures and non-toxic media.From the technical point of view, the vitrification method is simple and relatively easily applicable under field conditions.The authors review the current procedures applied to oocytes and embryos of laboratory and farm animals.
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