scholarly journals Morphokinetics of Porcine and Bovine Embryos and Anomalies in Their Development

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Wiesak T ◽  
◽  
Goryszewska-Szczurek E ◽  
Wasielak-Politowska M ◽  
◽  
...  
Keyword(s):  
Cell Division ◽  
Monitoring System ◽  
Time Lapse ◽  
Blastocyst Stage ◽  
Bovine Embryos ◽  
Morphokinetic Parameters ◽  
Kinetics Of

The objective of this study was to evaluate the kinetics of bovine and porcine embryos that failed or developed to the blastocyst stage and anomalies in cleavage using a time-lapse monitoring system. The timing of early cleavages and their duration were similar for bovine and porcine embryos that developed to the blastocyst stage. There were differences in the time of first and second cell division of the bovine embryos that developed and those that did not develop to blastocyst stage (P=0.004 and P=0.002), respectively. Similarly, in case of porcine embryos such difference was observed only in the time of first cleavage (P=0.0001). Direct cleavage from 1-cell to 3 cells occurred in 13.47% and to more than 3 cells in 3.37% of porcine embryos whereas to 3-cells occurred in 4.23% of bovine embryos. The reverse cleavage was observed in 4.33% of porcine and 8.45% of bovine embryos. Conclusion: Our study showed: 1) The similarities in timing and duration of early cleavages of bovine and porcine embryos during development to the blastocyst stage, 2) Differences in morphokinetic parameters between bovine and porcine embryos developing or non-developing to the blastocyst, 3) Anomalies in cleaving of in vitro developing bovine and porcine embryos.

288 KINETICS OF FERTILIZATION, DEVELOPMENT, AND SEX RATIO OF IN VITRO-PRODUCED BOVINE EMBRYOS OBTAINED WITH FOUR DIFFERENT BULLS

2007 ◽  
Vol 19 (1) ◽  
pp. 259 ◽  
Author(s):  
M. Alomar ◽  
H. Tasiaux ◽  
S. Remacle ◽  
F. George ◽  
D. Paul ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Time Lapse ◽  
Blastocyst Stage ◽  
Bovine Embryos ◽  
In Vitro Production ◽  
Chi Square ◽  
Cell Stage ◽  
Chi Square Test ◽  
Kinetics Of

The between-bulls variation in in vitro fertility and the shift of sex ratio toward male embryos are two problems affecting the in vitro production (IVP) of bovine embryos. Our objective was to evaluate the possible correlation between the kinetics of fertilization, embryo development, and the sex ratio of the resulting embryos. In a first experiment, and using frozen-thawed semen of 4 different AI bulls, the kinetics of pronucleus (PN) formation was evaluated at 8, 12, and 18 h post-in vitro insemination (hpi) after fixation and staining with Hoechst 33342. Fertilized oocytes were classified in 3 PN stages: PN1: showing the first signs of sperm head decondensation; PN2: with two pronuclei of different sizes, the two being far from each other; and PN3: showing two symmetric pronuclei of equal size, close to each other. Differences between bulls were observed at each time point, but were greater at 12 hpi than at 8 or 18 hpi. At 8 hpi and 12 hpi, bull C showed a significantly faster PN formation by comparison with the 3 other bulls (chi-square test: P < 0.05), whereas at 18 hpi, the proportion at each of the PN stages was similar to that of bulls A and D, with bull B showing delayed PN development. In a second experiment, a standard IVP procedure was conducted with the 4 bulls to determine cleavage and blastocyst rates. The timing of first cleavage was measured using time-lapse cinematography. Compared with those of bull B, the embryos generated with bull C led to significantly higher Day 7 blastocyst yields (31.3 � 9.5% vs. 21.9 � 6.7%; ANOVA: P < 0.05). Moreover, the embryos from bull C reaching the blastocyst stage cleaved faster (first cleavage at 23.1 � 2.1 hpi vs. 25.4 � 2.7 hpi for bull B; ANOVA: P < 0.05). In a third experiment, 65 to 76 Day 8 blastocysts were sexed per bull. Embryo sexing was performed by PCR using the co-amplification of a Y-specific bovine SRY sequence and an autosomal btRep-137 sequence. Only blastocysts obtained with bull C showed a shift in sex ratio toward male embryos (76.0% male embryos vs. 53.8% for bull B; chi-square test: P < 0.05), whatever the size of the blastocyst. The shift in sex ratio was already present at the 2-cell stage (64.2% male embryos; n = 53; chi-square test: P < 0.05). In conclusion, for 2 out of 4 bulls, a correlation was observed between the kinetics of PN formation, the timing of first cleavage, and the sex ratio of the resulting embryos.

scholarly journals Analysis of Morphokinetic Parameters of Feline Embryos Using a Time-Lapse System

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 748
Author(s):  
Joanna Kochan ◽  
Agnieszka Nowak ◽  
Barbara Kij ◽  
Sylwia Prochowska ◽  
Wojciech Niżański
Keyword(s):  
Embryo Development ◽  
Embryo Quality ◽  
Time Lapse ◽  
Blastocyst Stage ◽  
Cavity Formation ◽  
Non Invasive ◽  
Morphokinetic Parameters ◽  
Morphological Defects ◽  
Development In Vitro

The aim of this study was to analyze the morphokinetic parameters of feline embryos using a time lapse system. Oocytes matured in vitro were fertilized (IVF) and in vitro cultured in a time lapse-system (Primo Vision®, Gothenburg, Sweden). The first cell division of embryos occurred between 17 h post insemination (hpi) and 38 hpi, with the highest proportion of embryos (46%) cleaving between 21 and 24 hpi. The timing of the first cleavage significantly affected further embryo development, with the highest development occurring in embryos that cleaved at 21–22 hpi. Embryos that cleaved very early (17–18 hpi) developed poorly to the blastocyst stage (2%) and none of the embryos that cleaved later than 27 hpi were able to reach the blastocyst stage. Morphological defects were observed in 48% of the embryos. There were no statistically significant differences between the timing intervals of the first cleavage division and the frequency of morphological defects in embryos. Multiple (MUL) morphological defects were detected in more than half (56%) of the abnormal embryos. The most frequent single morphological defects were cytoplasmic fragmentation (FR) (8%) and blastomere asymmetry (AS) (6%). Direct cleavage (DC) from 1–3 or 3–5 blastomeres, reverse cleavage (RC) and vacuoles were rarely observed (2–3%). The timing of blastocyst cavity formation is a very good indicator of embryo quality. In our study, blastocyst cavity formation occurred between 127–167 hpi, with the highest frequency of hatching observed in blastocysts that cavitated between 142–150 hpi. Blastocysts in which cavitation began after 161 h did not hatch. In conclusion, the timing of the first and second cleavage divisions, the timing of blastocyst cavity formation and morphological anomalies can all be used as early and non-invasive indicators of cat embryo development in vitro.

Developmental kinetics of in vitro produced bovine embryos: the effect of sex, glucose and exposure to time-lapse environment

Zygote ◽  
2001 ◽  
Vol 9 (2) ◽  
pp. 105-113 ◽  
Author(s):  
J. Peippo ◽  
M. Kurkilahti ◽  
P. Bredbacka
Keyword(s):  
Sex Determination ◽  
Video Recording ◽  
Time Lapse ◽  
Recording System ◽  
Bovine Embryos ◽  
Cell Stage ◽  
Developmental Potential ◽  
Kinetics Of ◽  
Time Lapse Video

In this study, a simple time-lapse video recording system was used to compare developmental kinetics of female and male bovine embryos produced in vitro. Following embryo sex determination, the timing of each cleavage up to the 4-cell stage was compared between the sexes from the videotapes after culture in the presence and absence of glucose. In the second experiment, the consequences of exposure to a time-lapse video recording (TL) environment were studied by culturing embryos further until day 7 in an incubator, followed by collection and sex determination of morulae and blastocysts. In the absence of glucose, female embryos cleaved earlier than male ones. In the presence of glucose, however, male embryos cleaved earlier than female ones. There was no difference in the number of morulae/blastocysts in the absence of glucose, but in the presence of glucose more male than female embryos reached the morula and blastocyst stage. Exposure to the TL environment itself also had a sex-related effect, being more detrimental to male than female embryos. The difference in the number of functional X chromosomes between the sexes during early preimplantation development could explain these findings. In females, an increased capacity for oxygen radical detoxification through the pentose phosphate pathway could result in a reduced cleavage rate. Furthermore, glucose may influence the expression of enzymes located on the X chromosome. According to these results, a simple time-lapse video recording system is suitable for investigating embryo developmental kinetics and perhaps for the selection of embryos with the greatest developmental potential.

Morphokinetics and in vitro developmental potential of monopronucleated ICSI zygotes until the blastocyst stage

Zygote ◽  
2020 ◽  
Vol 28 (3) ◽  
pp. 217-222
Author(s):  
Silvia Mateo ◽  
Francesca Vidal ◽  
Beatriz Carrasco ◽  
Ignacio Rodríguez ◽  
Buenaventura Coroleu ◽  
...  
Keyword(s):  
Blastocyst Stage ◽  
Control Group ◽  
Study Group ◽  
Comprehensive Understanding ◽  
Developmental Potential ◽  
Morphokinetic Parameters ◽  
Developmental Capacity ◽  
Blastocyst Rate ◽  
Kinetics Of

SummaryThe aim of this study was to provide a more comprehensive understanding of 1PN intracytoplasmic sperm injection (ICSI) zygotes. To achieve this objective, we assessed whether all 1PN-derived embryos showed a similar morphokinetic pattern, and if the morphokinetic behaviour of 1PN-derived embryos was comparable with that of 2PN-derived embryos. In total, 149 1PN ICSI zygotes (study group) and 195 2PN ICSI zygotes (control group) were included in the study. Embryo development potential was evaluated in terms of blastocyst rate. Morphokinetic parameters, including the pronucleus diameter and kinetics of in vitro development, were also analyzed. Embryos derived from 1PN ICSI zygotes showed impaired development compared with 2PN-derived embryos, with blastocyst rates of 28.9% and 67.2%, respectively. The diameter of the pronucleus of 1PN zygotes was larger than that of 2PN zygotes. When compared with 2PN-derived embryos, those derived from 1PN zygotes had a visible pronucleus for a shorter time, in addition to a longer syngamy time and slower kinetic behaviour from two to nine cells. When 1PN-derived blastocysts and 2PN-derived blastocysts were compared, the developmental kinetics were similar in both groups, except for a delayed and longer duration of the compaction phase in 1PN-derived embryos. In conclusion, monopronucleated ICSI zygotes present differences in developmental capacity and morphokinetic behaviour compared with 2PN ICSI zygotes, showing particular morphokinetic parameters related to pronucleus formation. Only the 1PN ICSI-derived embryos that reached the blastocyst stage have similar morphokinetic development to blastocysts from 2PN zygotes.

278 EFFECT OF FOLLICULAR WAVE SYNCHRONIZATION AND SUPERSTIMULATION ON THE NORMALITY OF BOVINE EMBRYOS PRODUCED IN VITRO

2010 ◽  
Vol 22 (1) ◽  
pp. 296 ◽  
Author(s):  
K. Imai ◽  
T. Somfai ◽  
M. Ohtake ◽  
Y. Inaba ◽  
Y. Aikawa ◽  
...  
Keyword(s):  
Cell Division ◽  
Development Program ◽  
Time Lapse ◽  
Oocyte Quality ◽  
Blastocyst Stage ◽  
In Vitro Production ◽  
Cell Stage ◽  
Follicular Wave ◽  
Significant Difference

We previously reported that follicular wave synchronization by dominant follicle removal on Day 5 and the start of a superstimulatory treatment on Day 7 after ovum pick-up (OPU) was effective to increase oocyte quality (Imai et al. 2008 Reprod. Fertil. Dev. 20, 182). The present study was designed to examine the effect of superstimulatory treatment-induced follicular wave synchronization on quality of embryos obtained by OPU and in vitro production. Japanese Black cows were reared under the same feeding and environmental conditions and 2 OPU sessions were conducted in each cow. The first OPU session was performed in 7 cows at arbitrary days of estrous cycle using a 7.5-MHz linear transducer with needle connected to an ultrasound scanner. Then, follicles larger than 8 mm in diameter were aspirated and CIDR was inserted on Day 5 (the day of first OPU session = Day 0). The cows then received 30 mg of FSH twice a day from Days 7 to 10 in decreasing doses (4, 4, 3, 3, 2, 2, 1, 1 mg per shot) by i.m. injections. Cloprostenol (PGF; 0.75 mg) was administered in the morning of Day 9. The second OPU session was performed 48 h after PGF administration (Day 11) and only follicles larger than 5 mm in diameter were aspirated. The CIDR was removed from the cows just before OPU. Grade 1 and 2 cumulus oocyte complexes were in vitro matured, fertilized (IVF), and cultured as described by Imai et al. (2006 J. Reprod. Dev. 52, Suppl. S19-29). Some zygotes were fixed and stained to check their sperm penetration. Embryo development was monitored by time-lapse cinematography for 168 h after IVF. Cleavage pattern of embryos was classified morphologically into normal and abnormal (including those with multiple fragments, protrusions, 3 to 4 blastomeres, and uneven cell division) groups at their first cleavage. Normal penetration rate of second OPU session was significantly (P < 0.05) higher than that of the first OPU session. There were no differences in the mean percentage of total blastocyst and grade 1 blastocyst rates between the first (45.2 and 46.9%, respectively) and second (47.5 and 41.8%, respectively) OPU sessions. However, the rates of blastocysts developing from embryos that were beyond the 4-cell stage at 48 h after IVF was significantly (P < 0.05) higher after the second OPU session (81.2%) than after the first OPU session (67.4%). Furthermore, a significant difference (P < 0.05) was found in the rates of normal cleavage at the first cell division in embryos that developed to the blastocyst stage between the first and second OPU sessions (53.3% and 73.9%, respectively). These results indicate that superstimulatory treatment-induced follicular wave synchronization improved the normality of fertilization and development of cattle oocytes obtained by OPU. This work was supported by the Research and Development Program for New Bio-industry Initiatives.

237 THE EFFECTS OF BULLS AND X-SORTING OF SPERM ON THE ACCURACY OF NONINVASIVE CRITERIA TO PREDICT BLASTOCYST FORMATION OF IN VITRO-PRODUCED BOVINE EMBRYOS

2015 ◽  
Vol 27 (1) ◽  
pp. 208
Author(s):  
S. Matoba ◽  
T. Somfai ◽  
T. Nagai ◽  
M. Geshi
Keyword(s):  
Formation Rate ◽  
Calf Serum ◽  
Time Lapse ◽  
Blastocyst Stage ◽  
Developmental Competence ◽  
Bovine Embryos ◽  
Blastocyst Formation ◽  
Blastocyst Development ◽  
Chi Square

Previously, an early first cleavage and a second cleavage after IVF with a normal cleavage pattern defined by even blastomeres without fragments or protrusions was found to be a potent marker for the selection of embryos with high developmental competence (Sugimura et al. 2012 PLoS ONE 7, e36627). The aim of this study was to investigate the effects of bulls and X-sorting of sperm on the ability of these simple noninvasive markers to predict the potency of bovine IVF embryos to develop to the blastocyst stage in vitro. Immature oocytes were matured in TCM199 supplemented with 0.02 armour unit mL–1 FSH and 5% calf serum at 38.5°C in 5% CO2 and 95% air for 22 to 23 h. After maturation, oocytes were inseminated with either of non-sorted frozen-thawed sperm from 3 bulls (A–C) or X-sorted sperm of bull A. Putative zygotes were cultured (IVC) in CR1aa medium supplemented with 5% calf serum and 0.25 mg mL–1 linoleic acid albumin at 38.5°C in 5% CO2, 5% O2, and 90% N2 for 216 h. Embryo kinetics were observed individually by time-lapse cinematography (CCM-1.3Z; Astec, Fukuoka, Japan; Sugimura et al. 2010 Biol. Reprod. 83, 970–978). First and second cleavage kinetics and pattern were categorized according to Sugimura et al. (2012). For each bull, blastocyst development from embryos possessing the following 3 selection markers was compared: (marker 1) the first cleavage within 28 h after IVF, (marker 2) marker 1 combined with 2 even blastomeres without fragments or protrusions, and (marker 3) marker 2 combined with the second cleavage within 50 h after IVF with ≥6 even blastomeres without fragments or protrusions, respectively. Data were analysed by the Yates' corrected chi-square test. A total of 823 oocytes were used in at least 3 replications. When non-sorted sperm was used for IVF, there was not difference (P > 0.05) in total blastocyst formation rates on Day 8 (Day 0 = IVF) among bulls (ranging between 49.5 and 60.8%); however, blastocyst formation rate of embryos generated from X-sorted sperm of bull A (39.5%) was lower (P < 0.05) compared with other groups despite of similar cleavage rates. Embryos having marker 3 criteria developed to the blastocysts stage at significantly higher rates than those having marker 1 criteria in case of non-sorted sperm of bulls A, B, C, and X-sorted sperm of bull A (75.9, 87.0, 90.0, and 75.0% v. 59.5, 62.2, 63.6, and 46.3%, respectively). In groups produced from non-sorted sperm of bulls A, B, C, and X-sorted sperm of bull A, blastocyst development rates of embryos with marker 2 criteria (73.7, 75.0, 90.0, and 65.8%, respectively) were higher (P < 0.05) than those of embryos having marker 1 criteria but did not differ significantly from those with marker 3 criteria. Our results reveal that a first cleavage within 28 h after IVF to 2 even blastomeres without fragments or protrusions are potent predictive markers of the developmental competence of bovine embryos to the blastocyst stage regardless of bulls and sperm sorting.Research was partly supported by JSPS KAKENHI (26450388).

208 TIME LAPSE CINEMATOGRAPHIC ANALYSIS OF CLEAVAGE AND BLASTULATION IN BOVINE EMBRYOS OBTAINED BY OVUM PICKUP AND IN VITRO FERTILIZATION

2009 ◽  
Vol 21 (1) ◽  
pp. 202
Author(s):  
K. Imai ◽  
T. Somfai ◽  
Y. Inaba ◽  
Y. Aikawa ◽  
M. Ohtake ◽  
...  
Keyword(s):  
In Vitro Fertilization ◽  
Calf Serum ◽  
Development Program ◽  
Time Lapse ◽  
Blastocyst Stage ◽  
Bovine Embryos ◽  
Blastocyst Development ◽  
Vitro Fertilization ◽  
Cell Divisions

Since the 1980s, several different bovine in vitro embryo production systems have been developed, and more than 291 000 embryos have been transferred throughout the world (Thibier M 2007 IETS Newsletter 25(4), 15–20). However, we have limited knowledge about the cleavage pattern of the first, second, and third cell divisions and the developmental activities of embryos during in vitro culture (IVC). The present study was conducted to determine the developmental activities of bovine embryos obtained by ovum pickup (OPU), in vitro maturation (IVM), and in vitro fertilization (IVF). We analyzed embryonic development by time-lapse cinematography (TLC). A total of 92 cumulus–oocyte complexes were collected by OPU from Japanese Black cows and were subjected to IVM and IVF as reported previously (Imai et al. 2006 J. Reprod. Dev. 52(Suppl.), S19–S29). Inseminated oocytes were cultured in microdrops of CR1aa medium supplemented with 5% calf serum covered by mineral oil in 5% CO2 in air at 38.5°C. Kinetics of embryo development were measured by TLC for 168 h after IVF by using a Cultured Cell Monitoring System (CCM–M1.4ZS, Astec, Fukuoka, Japan). A total of 672 photographs of the embryos were taken (1 photograph every 15 min) during IVC. Image stacks were analyzed by the CCM–M1.4 software. Timing of the first, second, and third cell divisions, blastulation, and embryonic contractions were recorded. The results are reported as time (h) passed after insemination. In total, 75 (81.5%) embryos cleaved and 61 (66.3%) embryos developed to the blastocyst stage. The first, second, and third cell divisions in these viable embryos occurred at 24.0 ± 0.5, 32.1 ± 0.2, and 39.4 ± 0.4 h (mean ± SE) after IVF, respectively. On the other hand, in nonviable embryos (those that failed to develop to the blastocyst stage; n = 14), these cell divisions occurred at 29.5 ± 2.2, 41.3 ± 3.3, and 57.2 ± 7.6 h after IVF, respectively. There tended to be a difference (P = 0.06; paired t-test) in the timing of the first cell division between viable and nonviable embryos. Blastulation of embryos began at 114.4 ± 1.1 h, embryos developed to the blastocyst stage at 127.3 ± 1.4 h, and blastocysts began to expand at 138.4 ± 1.7 h after IVF, respectively. During blastocyst development, embryonic contractions (shrinkage attributable to the rupture of the blastocoele) and tight-shrinkage (shrinking of the embryo to less than 70% of its surface area) were observed in all embryos. The mean numbers of contractions and tight-shrinkages in blastocysts were 5.3 ± 2.7 and 2.1 ± 1.0 times, respectively. The frequency of contractions from the beginning of blastulation to the blastocyst stage was significantly lower (P < 0.01) than after the blastocyst stage. It took 6.9 ± 4.6 h for the embryos to re-expand after the tight-shrinkages. These results indicate that viable in vitro-produced embryos can be selected at early stages by TLC. Further studies are necessary to clarify the importance of the pulsating activity in OPU–IVF embryos. This work was supported by the Research and Development Program for New Bio-industry Initiatives.

P–207 Heterogoneic cell division proven to occur in bovine zygotes

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
T D Coster ◽  
H Masset ◽  
O Tsuiko ◽  
K Smits ◽  
A Va. Soom ◽  
...  
Keyword(s):  
Cell Division ◽  
Copy Number ◽  
Time Lapse ◽  
Chromosomal Mosaicism ◽  
Whole Genome ◽  
Bovine Embryos ◽  
Developmental Potential ◽  
Registration Number

Abstract Study question We hypothesize that the zygote can segregate parental genomes via a non-canonical pathway. We coined this heterogoneic cell division. Can we proof the existence of this new segregational pathway? Summary answer We confirmed the existence of this non-canonical segregation mechanism leading to mixoploidy and provide a catalogue of abnormal zygotic divisions. What is known already Embryos show a high degree of chromosomal instability leading to chromosomal mosaicism. Chromosomal aberrations affect the developmental potential. We developed haplarithmisis which determines the single-cell genome-wide haplotype and copy number and allows to deduce the parental and segregational origin. Analysis of cleavage-stage bovine embryos by haplarithmisis, discovered the presence of uniparental and biparental blastomere lineages in individual embryos. We hypothesized that whole genome segregations can occur via a non-canonical zygotic division, a process termed “heterogoneic” division. Abnormal zygotic division has been observed in bovine and human in vitro produced zygotes using time-lapse, but parental genome segregation has never been disclosed. Study design, size, duration We hypothesized that abnormal cytokinetics and spindle mechanics may underlie the segregation of parental genomes in a separate blastomere line. In vitro produced zygotes were monitored by time-lapse microscopy. Zygotes cleaving 3 or 4 cells were disaggregated, picked and analysed by haplarithmisis. Participants/materials, setting, methods Blastomeres from bovine in vitro produced zygotes cleaving directly into 3 or 4 blastomeres, identified by time-lapse monitoring, were tubed following zona removal and blastomere dissociation and whole-genome amplified. Samples were subsequently hybridized on Illumina Bovine HD BeadChip SNP arrays. Data was analyzed by haplarithmisis, using a the siCHILD-bovine algorithm, to infer the haplotypes and the copy number of the parental genomes. Blastomeres showing failed haplarithmisis plots were low-coverage whole-genome sequenced on a HiSeq4000 sequencer. Main results and the role of chance: We obtained 25 bovine embryos, comprising 82 blastomeres, derived from 12 families (12 cows and 2 bulls) that cleaved directly into 3 or 4 blastomeres. Sixteen, 7 and 2 out of 25 zygotes cleaved respectively in 3 cells, 4 cells and 3 cells and a fragment. In at least 20 embryos, more than one paternal haplotype was identified, showing that a polyspermic fertilization resulted in an abnormal division. All embryos contained a whole-genome abnormality in at least one blastomere, resulting in mixoploid (5), mixed diploid biparental and androgenetic (12), polyploid (4), mixed gynogenetic and androgenetic (2) and androgenetic (2) embryos. Twenty-one embryos had at least one blastomere containing a uniparental signature. Based on the blastomere haplotype profiles we classified the embryos in six segregation categories. In twelve blastomeres haplarithmisis failed. Massive parallel sequencing of the amplified DNA showed the presence of mitochondrial DNA, indicating the blastomere did not contain any genomic DNA. This observation confirms that heterogoneic cell division does occur via different non-canonical zygotic segregations, which result in a variety of chimeric and mixoploid embryos constitutions. Limitations, reasons for caution These findings apply to a small set of bovine in vitro produced abnormally cleaving embryos. Segregation patterns may be incomplete and their true in vitro and in vivo prevalence remains unknown. Based on the haplotypes the non-canonical divisions have been reconstructed. Those patterns can now be evaluated and tested. Wider implications of the findings: This study shows that heterogoneic cell division occurs. We hypothesize this non-canonical division occurs frequently in both in vitro and in vivo, not only in cattle but also in man and hypothesize that persistence of such cell lines might explain the development of androgenetic tumorous outgrowths and mosaic uniparental individuals. Trial registration number Not applicable

scholarly journals Cytokinesis and Midzone Microtubule Organization inCaenorhabditis elegans Require the Kinesin-like Protein ZEN-4

1998 ◽  
Vol 9 (8) ◽  
pp. 2037-2049 ◽  
Author(s):  
William B. Raich ◽  
Adrienne N. Moran ◽  
Joel H. Rothman ◽  
Jeff Hardin
Keyword(s):  
Cell Division ◽  
Null Allele ◽  
Time Lapse ◽  
Equatorial Region ◽  
Microtubule Organization ◽  
Dividing Cells ◽  
Spindle Midzone ◽  
Cross Links ◽  
Complete Cell

Members of the MKLP1 subfamily of kinesin motor proteins localize to the equatorial region of the spindle midzone and are capable of bundling antiparallel microtubules in vitro. Despite these intriguing characteristics, it is unclear what role these kinesins play in dividing cells, particularly within the context of a developing embryo. Here, we report the identification of a null allele ofzen-4, an MKLP1 homologue in the nematodeCaenorhabditis elegans, and demonstrate that ZEN-4 is essential for cytokinesis. Embryos deprived of ZEN-4 form multinucleate single-celled embryos as they continue to cycle through mitosis but fail to complete cell division. Initiation of the cytokinetic furrow occurs at the normal time and place, but furrow propagation halts prematurely. Time-lapse recordings and microtubule staining reveal that the cytokinesis defect is preceded by the dissociation of the midzone microtubules. We show that ZEN-4 protein localizes to the spindle midzone during anaphase and persists at the midbody region throughout cytokinesis. We propose that ZEN-4 directly cross-links the midzone microtubules and suggest that these microtubules are required for the completion of cytokinesis.

scholarly journals 136 EVIDENCE OF A DIRECT EFFECT OF P4 ON IVF-DERIVED BOVINE 8-CELL EMBRYOS

2005 ◽  
Vol 17 (2) ◽  
pp. 219 ◽  
Author(s):  
C.E. Ferguson ◽  
T.R. Davidson ◽  
M.R.B. Mello ◽  
A.S. Lima ◽  
D.J. Kesler ◽  
...  
Keyword(s):  
Embryo Development ◽  
Direct Effect ◽  
Blastocyst Stage ◽  
Control Group ◽  
Bovine Embryo ◽  
Bovine Embryos ◽  
Direct Role ◽  
Treatment Groups ◽  
And Control

There has been much debate over a direct role for progesterone (P4) in early bovine embryo development. While previous attempts to supplement bovine embryos in vitro with P4 produced results that vary and are often contradictory, this may be a response of administering P4 at inappropriate times. Therefore, the objective of these experiments was to determine if P4 could exert a direct effect on developing IVF-derived bovine embryos when administered at an appropriate time of embryo development. In Exp. I, IVF-derived bovine 8-cell embryos were randomly allotted to treatments: (1) control, CR1aa medium (n = 168); (2) vehicle, CR1aa + ETOH (0.01%) (n = 170); and (3) P4, CR1aa + ETOH + P4 (20 ng/mL in 50-μL droplet) (n = 173). In Exp. II, IVF-derived bovine 8-cell embryos were randomly allotted to treatments: (1) control, CR1aa medium (n = 160); (2) vehicle, CR1aa + DMSO (0.01%) (n = 180); and (3) P4, CR1aa + DMSO (0.01%) + P4 (20 ng/mL in 50-μL droplet) (n = 170). All embryos were evaluated on Days 6 to 9 post-insemination and rates calculated from 8-cell embryos. In Exp. I, ETOH tended to have a detrimental effect with significantly fewer (P < 0.05) embryos (53%) developing to the blastocyst stage on Day 7 compared with the control (62%) and P4 (71%) groups. At Day 7, significantly more embryos cultured in P4 (71%) developed to the blastocyst stage compared with the control group (62%). P4 treatment significantly increased the number of Grade 1 blastocysts (25%) on Day 7 compared with vehicle (15%) and control (17%) groups. At the end of culture, there were also significantly more Day 9 hatched blastocysts in the P4 group (33%) compared with vehicle (22%) and control (21%) groups. Supplementing P4 in the culture medium increased the rate of development, resulting in significantly more blastocysts (8%) on Day 6 and hatched blastocysts (21%) on Day 8 compared with vehicle (3% and 12%) and control (0% and 8%) groups, respectively. In Exp. II, there were no significant differences between treatment groups for Day 7 blastocysts (control 54%, DMSO 61%, P4 57%) and Day 9 hatched blastocysts (control 46%, DMSO 51%, P4 46%). However, there were significantly more Grade 1 blastocysts in the P4 group (22% and 36%) on Days 6 and 8 compared with vehicle (11% and 23%) and control (13% and 23%) groups, respectively. The lack of improvement in Day 7 blastocysts and Day 9 hatched blastocysts rates leads to further uncertainty in understanding the P4 vehicle interactions. In conclusion, the results of these two experiments indicate that P4 can exert a direct effect on the developing IVF-derived bovine embryo; however, due to P4 vehicle interactions; other inert vehicles need to be explored to further evaluate the direct effects of P4 on the developing bovine embryo.

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