Parthenogenetic Development Research Articles

Record of aphidophagous syrphids with their prey and host plants in India: A review

The article deals with the association of aphidophagous syrphids with their prey species and their host plants for programming the biocontrol approach against aphid pests. Aphids are tiny sap-sucking bugs and they are important phytophagous pests due to their polymorphism and rapid increase of their numbers by parthenogenetic development. Larvae of syrphids are the most important natural enemies of several sap-sucking insects and are useful bioagents in biological control programmes. After reviewing many articles 48 species of syrphids are recognised as predators of 72 aphid species infesting more than 141 plants of different families. Among these syrphids, Episyrphus balteatus was reported as a predator on maximum number of aphid species (43 species) followed by Ischiodon scutellaris (34 species), Eupeodes confrater (20 species), Betasyrphus serarius (18 species), Paragus serratus (17 species), and Allograpta javana (12 species).

Effects of bisphenol A and tauroursodeoxycholic acid on maturation of porcine oocytes and parthenogenetic development of embryos

Effects of bisphenol A and tauroursodeoxycholic acid on maturation of porcine oocytes and parthenogenetic development of embryos

105 Improving embryo parthenogenetic development in pigs by blastomere exchange

105 Improving embryo parthenogenetic development in pigs by blastomere exchange

Synergistic effects of follicle-stimulating hormone and epidermal growth factor on in vitro maturation and parthenogenetic development of red-rumped agouti oocytes.

Although oocyte in vitro maturation (IVM) is routinely used for in vitro embryo production in mice and rats, its use in wild rodents remains unexplored. Evidence suggests that hormone and growth factor supplementation influence oocyte meiotic resumption. This study evaluated the synergistic effects of follicle-stimulating hormone (FSH) and epidermal growth factor (EGF) on the IVM and parthenogenetic development of red-rumped agouti oocytes. Initially, we evaluated the IVM rates, mature oocyte quality, oocyte morphometry, and early embryonic development during IVM in the presence of 10, 50, and 75 mIU/mL FSH. No differences among the FSH concentrations were observed for IVM rates, oocyte morphometry, cumulus cell expansion, and viability. Although oocytes matured with 50 mIU/mL FSH showed a higher rate of cumulus expansion index (CEI), only oocytes matured with 10 mIU/mL FSH resulted in morulae after chemical activation (7.9% ± 4.2%). Thus, 10 mIU/mL FSH was used for further experiments. We subsequently evaluated the synergistic effects of 10, 50, and 100 ng/mL EGF and 10 mIU/mL FSH on the same parameters. No differences among the groups were observed in IVM rates, oocyte morphometry, and cumulus viability. Nevertheless, FSH with 10 ng/mL EGF showed a CEI superior to that of the other groups. Furthermore, oocytes matured with FSH alone or with both FSH and 10 or 50 ng/mL EGF developed morulae after activation (5.8%-8.3%). In conclusion, oocytes matured with 10 mIU/mL FSH and 10 ng/mL EGF are recommended for use in red-rumped agouti oocyte IVM, as they positively influence embryonic development.

Melatonin promotes parthenogenetic development of vitrified-warmed mouse MII oocytes, potentially by reducing oxidative stress through SIRT1

Previous studies have demonstrated that melatonin could ameliorate oxidative stress during the cryopreservation of mouse MII oocytes and their in vitro culture after parthenogenetic activation. However, the underlying molecular mechanism remained poorly understood. This study was conducted to investigate whether melatonin could modulate the oxidative stress in the parthenogenetic 2-cell embryos derived from vitrified-warmed oocytes through SIRT1. The results showed that the reactive oxygen species levels increased, the glutathione levels and SIRT1 expression decreased significantly in parthenogenetic 2-cell embryos derived from cryopreserved oocyte, and the parthenogenetic blastocyst formation rates significantly decreased when compared to those derived from control oocytes. These unfavorable phenomena were prevented by the addition of either 10−9 mol/L melatonin or 10−6 mol/L SRT-1720 (SIRT1 agonist), and it was restored by the supplementation of 10−9 mol/L melatonin in combination with 2 × 10−5 mol/L EX527 (SIRT1 inhibitor). Therefore, the findings from the present study concluded that melatonin may reduce oxidative stress via regulating SIRT1, and potentially promote the parthenogenetic development of vitrified-warmed mouse MII oocytes.

Achiasmatic meiosis in the unisexual Amazon molly, Poecilia formosa

Unisexual reproduction, which generates clonal offspring, is an alternative strategy to sexual breeding and occurs even in vertebrates. A wide range of non-sexual reproductive modes have been described, and one of the least understood questions is how such pathways emerged and how they mechanistically proceed. The Amazon molly, Poecilia formosa, needs sperm from males of related species to trigger the parthenogenetic development of diploid eggs. However, the mechanism, of how the unreduced female gametes are produced, remains unclear. Cytological analyses revealed that the chromosomes of primary oocytes initiate pachytene but do not proceed to bivalent formation and meiotic crossovers. Comparing ovary transcriptomes of P. formosa and its sexual parental species revealed expression levels of meiosis-specific genes deviating from P. mexicana but not from P. latipinna. Furthermore, several meiosis genes show biased expression towards one of the two alleles from the parental genomes. We infer from our data that in the Amazon molly diploid oocytes are generated by apomixis due to a failure in the synapsis of homologous chromosomes. The fact that this failure is not reflected in the differential expression of known meiosis genes suggests the underlying molecular mechanism may be dysregulation on the protein level or misexpression of a so far unknown meiosis gene, and/or hybrid dysgenesis because of compromised interaction of proteins from diverged genomes.

The Use of Parthenogenetic Clones to Create Highly Heterogeneous Hybrids of the Silkworm (Bombyx mori L.)

Since the entire world's sericulture, to achieve maximum heterosis is based on the feeding of hybrids of only the first generation, therefore, operations for the preparation of pure hybrids are of particular importance. In Uzbekistan, the Sericulture Research Institute has developed new biotechnologies specifically to solve this problem, and genetically modified breeds and parthenogenetic clones have been created on their basis. The unfertilized eggs are thermally activated at t = 46°C for 18 minutes, and the reducing division of meiosis in the germ cells of the silkworm is hampered. As a result, the eggs remain with a diploid set of chromosomes and develop as zygotes. Since silkworm females are heterogamous by sex chromosomes, only female parthenogenetic clones develop from thermally activated eggs. Clonal-breed hybrids, characterized by increased viability of caterpillars – 93,5-98,0% (in the control – 90,0%), the high cocoon shell ratio – 22,1-23,8% (in the control – 22,5%), increased egg-bearing capacity - 622-639 pcs (in the control - 630 pcs), metric number of thread - 3344-4065 units (in the control - 3321), the synchronicity of caterpillar development, uniformity of cocoons, ease of preparation. The technology of thermal activation of unfertilized silkworm eggs for parthenogenetic development is not particularly difficult, therefore clones can reproduce the required number of generations and in an unlimited number of individuals. The second component for hybridization can be males of almost any breed. Clones, due to their genetic constancy, do not need breeding and breeding selection, they do not need to be divided by gender, because they are represented by only one female sex, and have high combinational ability and amicable development.

Effects of microvibration stimulation on developmental potential of discarded germinal vesicle oocytes of human.

This research aims to study the effects of continuous microvibration stimulation on the parthenogenetic development of human germinal vesicle oocytes. Ninety-five discarded germinal vesicle oocytes from intracytoplasmic sperm injection treatment (ICSI) cycles performed at Amcare Women's & Children's Hospital between January and December 2021 were used for conventional static culture as well as 10Hz microvibration culture. We investigated the differences between the two groups in terms of oocyte maturation rate, parthenogenetic activation rate, and parthenogenetic blastocyst formation rate. The static culture and 10Hz microvibration culture of 95 oocytes showed that the parthenogenetic blastocyst formation rate in the microvibration culture group was significantly higher than those in the traditional static culture group. A continuous microvibration stimulation can significantly improve the parthenogenetic developmental potential of human immature oocytes.

Abolition of egg diapause by ablation of suboesophageal ganglion in parental females is compatible with genetic engineering methods

Microinjection of genetic material into non-diapause eggs is required for genetic engineering of silkworms. Besides diapause could be useful for maintaining transgenic lines, a drawback of this technology is that most standard silkworm strains and experimental lines of interest produce diapausing eggs. Several approaches have been developed to abolish diapause but none are very efficient. Here, we investigated the ablation of the suboesophageal ganglion (SG) in female pupae, which is a source of the hormone required to trigger egg diapause, as a mean to abolish diapause. We showed that SG-ablation is a reliable method to produce nondiapause eggs. Additionally, the challenge associated with lower fecundity of females with SG ablation was resolved by injecting pilocarpine into the mated female. We also investigated the suitability of nondiapause eggs laid by SG-ablated females for transgenesis, targeted mutagenesis, and induction of parthenogenetic development. Our results demonstrated SG-ablation to be a useful and simple method for expanding the possibilities associated with genetic engineering in silkworms.

Femtosecond laser oocyte enucleation as a low-invasive and effective method of recipient cytoplast preparation.

Recipient cytoplast preparation, commonly performed by DNA aspiration with a needle, inevitably leads to the loss of reprogramming factors. As an alternative to the traditional enucleation technique, femtosecond laser enucleation can eliminate DNA effectively without loss of reprogramming factors and without oocyte puncturing. In this work we have performed oocyte enucleation by destructing the metaphase plate using a 795 nm femtosecond laser. The disability of the enucleated oocytes to develop after the parthenogenetic activation, as well as the lack of DNA staining luminescence, strongly confirms the efficiency of the femtosecond laser enucleation. The parthenogenetic development of oocytes after the cytoplasm treatment suggests a low-invasive effect of the laser enucleation technique.

Ascorbic acid protects the toxic effects of aflatoxin B1 on yak oocyte maturation.

High-quality oocytes are a prerequisite for successful fertilization. Mammals feeding on aflatoxin-contaminated feed can cause reproductive toxicity, including follicular atresia, poor oocyte development and maturation, and aberrant epigenetic modifications of oocytes. In addition, the important role of ascorbic acid (AA) in reproductive biology has been confirmed, and AA is widely used as an antioxidant in cell culture. However, the toxic effects of aflatoxin B1 (AFB1 ) on yak oocytes and whether AA has protective effects remain unknown. In this study, we found that exposure to AFB1 impedes meiotic maturation of oocytes, promotes apoptosis by triggering high levels of reactive oxygen species (ROS), and disrupts mitochondrial distribution and actin integrity, resulting in a decrease in the fertilization ability and parthenogenetic development ability of oocytes. In addition, these injuries changed the DNA methylation transferase transcription level of mature oocytes. After adding 50 μg/ml AA, the indices recovered to levels close to those of the control group. The results showed that AA could protect yak oocytes from the toxic effects of AFB1 and improve the quality of oocytes.

Facultative Parthenogenesis in California Condors.

Parthenogenesis is a relatively rare event in birds, documented in unfertilized eggs from columbid, galliform, and passerine females with no access to males. In the critically endangered California condor, parentage analysis conducted utilizing polymorphic microsatellite loci has identified two instances of parthenogenetic development from the eggs of two females in the captive breeding program, each continuously housed with a reproductively capable male with whom they had produced offspring. Paternal genetic contribution to the two chicks was excluded. Both parthenotes possessed the expected male ZZ sex chromosomes and were homozygous for all evaluated markers inherited from their dams. These findings represent the first molecular marker-based identification of facultative parthenogenesis in an avian species, notably of females in regular contact with fertile males, and add to the phylogenetic breadth of vertebrate taxa documented to have reproduced via asexual reproduction.

PSX-B-11 Comparing effects of FGF2 and IGF1 on the development competence of parthenogenetic activated bovine oocytes maturing in vitro

Abstract The oocyte quality acquired during in vitro maturation (IVM) are the main limitative factors affecting the embryo production. The aim of the present research was to study effects of fibroblast growth factor 2 (FGF2) and insulin-like growth factor 1 (IGF1) during IVM of bovine oocytes on their developmental potential after parthenogenetic activation. Bovine cumulus-oocyte complexes (COC; n = 1176) were cultured for 22h in either standard maturation medium (TCM-199 supplemented with 10% fetal calf serum (FCS), 0.2 mM sodium pyruvate, 10 μg/ml FSH and 10 μg/ml LH; Control) or maturation medium supplemented with different concentrations (5–160 ng/ml) of FGF2 and IGF1. After IVM, matured oocytes activated by sequential treatment with ionomycin followed by DMAP and cyclohexamide and then cultured up to the blastocyst stage. The obtained blastocysts were fixed, and the total cell number and the level of apoptosis were determined using DAPI and TUNEL staining. The data from 4 replicates (77–91 oocytes per treatment) were analyzed by ANOVA. Cleavage rates of activated oocytes did not differ between groups and ranged from 63.7 to 68.1%. The addition of 10, 20 and 40 ng/ml of FGF2 to the IVM medium led to an increase in the yield of blastocysts [from 19.6±1.8% (Control) to 35.2±3.4, 29.8±1.9 and 31.1±2.1%, respectively (P<0.05)] and in the total cell number in embryos that developed to the blastocyst stage (P<0.05). Meanwhile, the blastocyst yield and the total cell number in blastocysts in the IGF1-treated groups were similar to that in the control group. No effects of both growth factors on the proportion of apoptotic nuclei in blastocysts (5.3–7.1%) were observed. Thus, FGF2 (but not IGF1) are able to maintain competence for parthenogenetic development of bovine COC during their maturation invitro. Supported by RFBR (18-29-07089) and the Ministry of Science and Higher Education of Russia.

ПРЕИМУЩЕСТВА ИСПОЛЬЗОВАНИЯ ПАРТЕНОГЕНЕТИЧЕСКИХ КЛОНОВ ТУТОВОГО ШЕЛКОПРЯДА (BOMBYX MORI L.) В ГИБРИДИЗАЦИИ

The fierce competition in the global silk market encourages the development and application of new biotechnologies in sericulture, such as cloning. The term “clone” in Greek means “branch”. A clone is an offspring of a single organism propagated without fertilization. All cloned individuals are genetically identical and are copies of each other. Clones are obtained in different ways. In case of the silkworm, this is a parthenogenetic development, which is an unnatural way of reproduction for the silkworm. Thermoactivation of an unfertilized greene at t0=46 0C during 18, leads to inhibition of the reduction division of meiosis in the silkworm germ cells. As a result, the eggs remain with a diploid set of chromosomes and develop as zygotes. Since the female cells in the sex chromosomes of the silkworm are heterogametic, only female parthenogenetic clones develop from thermally activated eggs. This feature makes silkworm clones extremely attractive for creating 100% pure hybrids. As the sericulture globally is based on the production of hybrids of the first generation only, in order to use maximum heterosis, the accuracy of preparation of hybrids is becoming particularly important.

Granulosa cells affect in vitro maturation and subsequent parthenogenetic development of buffalo (Bubalus bubalis) oocytes.

Granulosa cells (GCs) play a crucial role in follicular development and atresia. Previous studies have showed that GCs in the form of monolayer influenced in vitro maturation (IVM) of oocytes. However, the effects of GCs in the form of conditioned medium and monolayer on IVM and development competence of buffalo oocytes remain unclear. In the present study, we examined the impacts of GC-conditioned medium (GCCM) and monolayer GC on maturation efficiency and embryo development of buffalo oocytes after parthenogenetic activation (PA). Our results showed that GCCM that was collected on day 2 and added to IVM medium at a 20% proportional level (2days and 20%) exerted significant negative effects on IVM rate (41.6% vs. 44.5%), but significantly enhanced embryo development (oocyte cleavage, 81.3% vs. 69.3%; blastocyst formation, 36.3% vs. 29.3%) of buffalo oocytes after PA compared with the control group. Furthermore, monolayer GC significantly reduced both maturation efficiency (40.2% vs. 44.5%) and embryo development (oocyte cleavage, 60.6% vs. 69.3%; blastocyst formation, 20.6% vs. 29.3%) of buffalo oocytes after PA compared to the control group. Our study indicated that GCs in the form of GCCM (2days and 20%) and monolayer GC had different effects on IVM and subsequent parthenogenetic development of buffalo oocytes.

Mechanism of the adverse effect of hyaluronidase used for oocyte denudation on early development of bovine embryos.

Hyaluronidase is widely used in animal and human assisted reproductive technologies (ARTs) to remove cumulus cells around oocytes. However, adverse effects of hyaluronidase treatment, such as increased rates of degeneration and parthenogenesis, have been found after treatment of human and mouse oocytes. Currently, the mechanism(s) of the detrimental effects are unclear. The present study was initiated to identify the mechanism of adverse responses to hyaluronidase treatment in bovine oocytes and early embryos. Cumulus cells were removed from cumulus-oocyte complexes (COCs) with or without hyaluronidase and the oocytes were subjected to intracytoplasmic sperm injection (ICSI) or in vitro fertilization (IVF). Significantly lower rates of blastocyst formation were obtained in the hyaluronidase treatment group after ICSI (22.4%) and IVF (21.2%) compared with the non-hyaluronidase control groups: 36.1% after ICSI and 30.4% after IVF. Next, we examined the effect of hyaluronidase on parthenogenetic development rates and on the cytoplasmic levels of free calcium ions (Ca2+), reactive oxygen species (ROS) and reduced glutathione (GSH). No differences in parthenogenesis rates were found between treated and untreated groups. Ca2+ levels in oocytes from the hyaluronidase treatment group indicated using mean fluorescence intensity were significantly higher (68.8 ± 5.3) compared with in the control group (45.0 ± 2.5). No differences were found in the levels of ROS or GSH between the treated and untreated groups. We conclude that hyaluronidase might trigger an increase in Ca2+ levels in oocytes, resulting in a decreased potential for normal embryonic development.

133 Effect of cytokines on the quality bovine oocytes matured invitro

As has been shown previously, fibroblast growth factor 2 (FGF2), leukaemia inhibitory factor (LIF), and insulin-like growth factor 1 (IGF1) in combination play a positive role in maintaining the quality of mammalian oocytes maturing invitro. In the present work, we studied the effects of these cytokines in optimal concentrations when added in combination to IVM medium on the nuclear status and development competence of bovine oocytes. Slaughterhouse-derived cumulus–oocyte complexes (COC) (n=1107 COC) were cultured for 22h in either IVM medium [TCM-199 supplemented with 10% fetal calf serum (FCS), 0.2mM sodium pyruvate, 10μgmL−1 porcine FSH, and 10μgmL−1 ovine LH] (Control) or the same IVM medium supplemented with FGF2, LIF, and IGF1. The eight combinations of cytokines tested during maturation were (1) 20ngmL−1 LIF/10ngmL−1 IGF1/10ngmL−1 FGF2 (Group 1); (2) 20ngmL−1 LIF/10ngmL−1 IGF1/40ngmL−1 FGF2 (Group 2); (3) 20ngmL−1 LIF/20ngmL−1 IGF1/10ngmL−1 FGF2 (Group 3); (4) 20ngmL−1 LIF/20ngmL−1 IGF1/40ngmL−1 FGF2 (Group 4); (5) 5ngmL−1 LIF/10ngmL−1 IGF1/10ngmL−1 FGF2 (Group 5); (6) 5ngmL−1 LIF/10ngmL−1 IGF1/40ngmL−1 FGF2 (Group 6); (7) 5ngmL−1 LIF/20ngmL−1 IGF1/10ngmL−1 FGF2 (Group 7); and (8) 5ngmL−1 LIF/20ngmL− 1 IGF1/40ngmL−1 FGF2 (Group 8). After IVM, matured and denuded oocytes were activated by culturing in 5μM ionomycin solution for 5min followed by 4h in 2mM 4-dimethylaminopyridine (DMAP) and 10mgmL−1 cyclohexamide. Activated oocytes were cultured in CR1aa medium until Day 5 and then transferred to the same medium supplemented with 5% FCS and cultured until Day 7. All cultures were performed at 38.5°C and 5% CO2 in humidified air. At Days 2 and 7 after activation, the cleavage and blastocyst rates were determined. The data from 6 to 7 replicates (122–181 oocytes per treatment) were analysed by ANOVA. The rate of MII oocytes, assessed by the presence of the first polar body, did not differ between the groups and reached 67.1 to 84.5%. Cleavage rate was higher (84.5±2.9%, P<0.05) in Group 1 compared with Control (68.9±2.7%), Group 4 (67.1±4.9%) and Group 7 (66.6±2.0%), but not compared with Group 2 (76.5±4.8%), Group 3 (76.6±4.8%), Group 5 (78.2±3.1%), or Group 8 (79.9±3.1%). The percentage of blastocyst formation relative to the total number of MII oocytes in the control group was 19.6±2.4%. The culture of COC in Group 1 (20 ngmL−1 LIF/10ngmL−1 IGF1/10ngmL−1 FGF2) and Group 2 (20ngmL−1 LIF/10ngmL−1 IGF1/40ngmL−1 FGF2) caused the blastocyst yield to increase to 33.0±3.8 and 31.2±4.3%, respectively (P<0.05), whereas the culture COC in other cytokine-treated groups had no effect. In Groups 3 to 8, the blastocyst rates were 22.9±4.6, 19.2±3.0, 24.2±3.2, 27.8±1.7, 21.6±1.8, and 25.5±9.0%, respectively, and did not differ (except Group 4) compared with those of Group 1 and Group 2. In conclusion, LIF, FGF2, and IGF1 in optimal combinations can maintain competence for parthenogenetic development of bovine COC during their maturation invitro. This research was supported by RFBR (projects No. 18-29-07089) and the Ministry of Science and Higher Education of Russia.

The influence of the duration of in vitro maturation and incubation with an activating agent on the hatching capacity of bovine parthenotes - short communication

The period of both in vitro maturation (IVM) and incubation with oocyte activators affects the blastocyst yield following parthenogenetic activation (PA). Nevertheless, it is still unknown how these conditions impact the expansion and hatching rates of bovine parthenogenetic blastocysts. The objective of this study was to assess the influence of the duration of IVM and exposure to the activating agent, 6-dimethylaminopurine (6-DMAP), on a number of developmental parameters in bovine parthenotes, including: Cleavage, blastocyst formation, expansion, and hatching. Slaughterhouse oocytes were subjected to different periods of IVM. Subsequently, eggs were first parthenogenetically activated for five minutes with ionomycin and then incubated for distinct lengths of time with a second activator, 6-DMAP. The treatments were: a) Control: 22 h IVM/4 h 6-DMAP; b) 22 h IVM/5 h 6-DMAP; c) 24 h IVM/4 h 6-DMAP; and d) 24 h IVM/5 h 6-DMAP. Developmental stages were evaluated at day 4 and day 8 of in vitro culture (IVC). No differences were detected in most developmental parameters. However, the duration of IVM and incubation with 6-DMAP significantly affected (P<0.05) hatching capacity considering the number of blastocysts (Hatch./Blast.). Also, this same variable was higher (P<0.05) in group b) 22 h IVM/5 h 6-DMAP (45.89 ± 12.59%), as compared to c) 24 h IVM/4 h 6-DMAP (6.67 ± 6.67%). In conclusion, the length of IVM and incubation with 6-DMAP influenced parthenogenetic development, where 22 h IVM/5 h 6-DMAP was the condition producing the highest Hatch./Blast. rate in bovine parthenotes.

Housekeeping genes for RT-qPCR in ovine preimplantation embryos.

Housekeeping genes (HKG) are paramount for accurate gene expression analysis during preimplantation development. Markedly, quantitative reverse transcription polymerase chain reaction (RT-qPCR) in ovine embryos currently lacks HKGs. Therefore, we tested 11 HKGs for RT-qPCR normalization during ovine parthenogenetic preimplantation development. Seven HKGs reached the qPCR efficiency threshold (97.20-105.96%), with correlation coefficients ranging from -0.922 to -0.998 and slopes from -3.22 to -3.59. GeNorm ranked glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and TATA-binding protein (TBP) as the best HKG pair, while H3 histone, family 3A (H3F3A) was the third HKG. Relative gene expression was measured for zinc finger protein X-linked (ZFX) and developmental pluripotency-associated 3 (DPPA3) transcripts during ovine parthenogenetic preimplantation development. ZFX did not show any transcript abundance fluctuation among oocytes, cleavage-stage embryos, and morulae. DPPA3 transcript abundance was also similar among all developmental stages, therefore suggesting that it may not display a maternal gene expression profile. In silico analysis of ovine DPPA3 mRNA and protein showed high conservation to bovine orthologues. However, DPPA3 orthologues differed in regulatory motifs. In conclusion, GAPDH, TBP and H3F3A are stable HKGs in ovine parthenogenetic embryos and allow accurate RT-qPCR-based gene expression analysis.

Партеногенетическое развитие эмбрионов Bos taurus из ооцитов, созревших в различных системах культивирования

Abstract. Identification of the factors determining of donor’s oocyte competence to parthenogenetic development will allow developing an effective method for obtaining parthenotes to solve fundamental problems of regulating gene activity in ontogenesis, creating homozygous embryonic stem cell lines, improving the stages of cloning technology, and modeling of in vitro oocyte maturation media. The purpose of study is to evaluate the potencies of Bos taurus oocytes matured in different culture systems to cold shock-induced parthenogenesis. Methods. For oocyte maturation, culture systems of the following composition were used: 1 – TC-199 with 10 % fetal bovine serum (FBS), 50 μg/ml estradiol, 10 μg/ml luteinizing hormone, 10 μg/ml follicle-stimulating hormone; 2 – TC-199 with 10 % estrous serum of cows; 3 – TC-199 with 50 % fluid from follicles (Ø 3–8 mm); 4 – TC-199 with 50 % protein of follicular fluid (molecular weight of 65 kDa); 5 – TC-199 with 10 % FBS, 1×106 granulosa cells/ml medium; 6 – TC-199 with 10 % FBS and walls of follicles (Ø 6–8 mm); 7 – TC-199 with 10 % FBS, 1×106 granulosa cells/ml medium and walls of follicles (Ø 6–8 mm). After 24 hours of cultivation, the oocytes were activated by cold shock (exposure time 20 minutes, temperature 0…–4 °C. Results. The proportion of embryos at the stages of late morula and blastocysts from oocytes matured in system 7 was 45 % (58/129), which was significantly higher than in other systems: 1 – 28 % (39/141), P < 0.05; 2 – 31 % (42/137), P < 0.05; 3 – 25 % (33/133), P < 0.01; 4 – 18 % (25/139), P < 0.001; 5 – 31 % (41/132), P < 0.05; 6 – 33 % (43/129). The introduction of estradiol or structural components of antral follicles into the oocytes maturation medium contributed to an increase in the proportion of parthenotes at the preimplantation stages of development, including blastocysts, and a decrease in the level of degenerated embryos. Scientific novelty. A comparative morphological analysis of the potentials for parthenogenesis of bovine oocytes matured in various culture systems and activated by cold shock was carried out for the first time. Optimal systems for in vitro maturation of female gametes were proposed. Based on the analysis of the results, we recommend before induction to parthenogenesis bovine oocytes culture in media supplemented with 50 ng/ml estradiol or structural components of antral follicles producing estradiol.