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1
Morbidelli, Alessandro. "Calcium signals in planetary embryos." Nature 555, no. 7697 (March 2018): 451–52. http://dx.doi.org/10.1038/d41586-018-03144-1.
2
Wigginton, N. S. "The chronology of planetary embryos." Science 344, no. 6188 (June 5, 2014): 1128. http://dx.doi.org/10.1126/science.344.6188.1128-k.
3
Svetsov, Vladimir. "Cratering erosion of planetary embryos." Icarus 214, no. 1 (July 2011): 316–26. http://dx.doi.org/10.1016/j.icarus.2011.04.026.
4
Briand, C. H., S. Gauthier, J. F. Lemay, S. Laliberté, and M. F. Tremblay. "Relationship between field performance, family, embryo morphology, and isozyme heterozygosity, and in vitro reactivity in jack pine." Canadian Journal of Forest Research 28, no. 1 (January 1, 1998): 98–105. http://dx.doi.org/10.1139/x97-187.
Анотація:
The influence of field performance, family, embryo morphology, and isozyme heterozygosity level on in vitro reactivity of Pinus banksiana Lamb. was evaluated on embryos from five superior families, five inferior families, and a mixed seed lot. Embryo length, number of cotyledons, and isozyme heterozygosity were determined for each embryo. Seed germination and fresh weight were determined on a family level. On average, superior families showed higher percentages of embryos that formed buds in vitro. Within each performance class, the analysis based on initial number of embryos revealed differences among families for the percentage of green embryos and embryos with adventitious buds and shoots. When calculations were based on green embryos only, i.e., excluding embryos that remained white, there were no differences among families. Thus, the overall in vitro potential of a family appears to be strongly dependent upon the capacity of embryos to turn green. On a per family basis, seed germination was positively correlated with most in vitro characters, with the exception of mean shoot length per shoot-forming embryo. Small embryos had a lower probability of producing buds and shoots, and embryos with three cotyledons showed a higher mortality than embryos with four or more cotyledons. No significant relationships were observed between heterozygosity level and in vitro reactivity, with analyses performed on green embryos only.
5
Daryatmo, Daryatmo, Niken Ulupi, Rudi Afnan, and Wahyuni Wahyuni. "Article Review : Nutrition Stimulation with In ovo feeding Technology for Optimization of Growth and Development of Prenatal and Postnatal Periods of Chicken." Jurnal Ternak 14, no. 2 (October 20, 2023): 51. http://dx.doi.org/10.30736/jt.v14i2.185.
Анотація:
The improvement in broiler chicken performance is currently thanks to the genetic selection, nutrition, maintenance management, and health and biosecurity programs that have succeeded in improving the maintenance performance of broilers. Such rapid development in the cycle after hatching is undoubtedly also influenced by the embryo's development or the prenatal phase. Unlike other mammals, the process of breeding poultry has its characteristics where the process of embryonic development occurs outside the body of livestock or inside poultry eggs. Chicken embryos rely heavily on the nutrients inside the egg, which provide the energy and amino acid makeup needed for the metabolic needs of the growing embryo during the 21-day incubation process. Chicken embryos are susceptible to a lack of energy during the hatching process. This deficiency can result in weak embryos and, in more severe conditions, embryo death and failure to hatch. The nutritional needs of embryos during incubation can be added to the egg with the in ovo feeding technique. The in ovo feeding technique is a technique that allows the addition of outside nutrients injected into the egg during incubation for the developmental and metabolic needs of the embryo, as well as to improve the nutritional status of the egg. Nutrition stimulation with in ovo feeding technique produces many benefits, such as increasing hatchability, hatching weight, immunity level, reduced bone system disorders, reduced morbidity and mortality after hatching, feed efficiency and weight gain.
6
Emsenhuber, Alexandre, Christoph Mordasini, Remo Burn, Yann Alibert, Willy Benz, and Erik Asphaug. "The New Generation Planetary Population Synthesis (NGPPS)." Astronomy & Astrophysics 656 (December 2021): A70. http://dx.doi.org/10.1051/0004-6361/202038863.
Анотація:
Context. Planetary formation and evolution is a combination of multiple interlinked processes. Constraining the mechanisms observationally requires statistical comparison to a large diversity of planetary systems. Aims. We want to understand global observable consequences of different physical processes (accretion, migration, and interactions) and initial properties (like disc masses and metallicities) on the demographics of the planetary population. We also want to study the convergence of our scheme with respect to one initial condition, the initial number of planetary embryo in each disc. Methods. We selected distributions of initial conditions that are representative of known protoplanetary discs. Then, we used the Generation III Bern model to perform planetary population synthesis. We synthesise five populations with each a different initial number of Moon-mass embryos per disc: 1, 10, 20, 50, and 100. The last is our nominal population consisting of 1000 stars (systems) that was used for an extensive statistical analysis of planetary systems around 1 M⊙ stars. Results. The properties of giant planets do not change much as long as there are at least ten embryos in each system. The study of giants can thus be done with simulations requiring less computational resources. For inner terrestrial planets, only the 100-embryos population is able to attain the giant-impact stage. In that population, each planetary system contains, on average, eight planets more massive than 1 M⊕. The fraction of systems with giants planets at all orbital distances is 18%, but only 1.6% are at >10 au. Systems with giants contain on average 1.6 such planets. The planetary mass function varies as M−2 between 5 and 50 M⊕. Both at lower and higher masses, it follows approximately M−1. The frequency of terrestrial and super-Earth planets peaks at a stellar [Fe/H] of −0.2 and 0.0, respectively, being limited at lower [Fe/H] by a lack of building blocks, and by (for them) detrimental growth of more massive dynamically active planets at higher [Fe/H]. The frequency of more massive planets (Neptunian, giants) increases monotonically with [Fe/H]. The fast migration of planets in the 5–50 M⊕ range is reduced by the presence of multiple lower-mass inner planets in the multi-embryos populations. To assess the impact of parameters and model assumptions, we also study two non-nominal populations: insitu formation without gas-driven migration, and a different initial planetesimal surface density. Conclusions. We present one of the most comprehensive simulations of (exo)planetary system formation and evolution to date. For observations, the syntheses provides a large data set to search for comparison synthetic planetary systems that show how these systems have come into existence. The systems, including their full formation and evolution tracks are available online. For theory, they provide the framework to observationally test the global statistical consequences of theoretical models for specific physical processes. This is an important ingredient towards the development of a standard model of planetary formation and evolution.
7
Coleman, Gavin A. L. "From dust to planets – I. Planetesimal and embryo formation." Monthly Notices of the Royal Astronomical Society 506, no. 3 (July 6, 2021): 3596–614. http://dx.doi.org/10.1093/mnras/stab1904.
Анотація:
ABSTRACT Planet formation models begin with proto-embryos and planetesimals already fully formed, missing out a crucial step, the formation of planetesimals/proto-embryos. In this work, we include prescriptions for planetesimal and proto-embryo formation arising from pebbles becoming trapped in short-lived pressure bumps, in thermally evolving viscous discs to examine the sizes and distributions of proto-embryos and planetesimals throughout the disc. We find that planetesimal sizes increase with orbital distance, from ∼10 km close to the star to hundreds of kilometres further away. Proto-embryo masses are also found to increase with orbital radius, ranging from $10^{-6}{\, {\rm M}_{\oplus }}$ around the iceline, to $10^{-3}{\, {\rm M}_{\oplus }}$ near the orbit of Pluto. We include prescriptions for pebble and planetesimal accretion to examine the masses that proto-embryos can attain. Close to the star, planetesimal accretion is efficient due to small planetesimals, whilst pebble accretion is efficient where pebble sizes are fragmentation limited, but inefficient when drift dominated due to low accretion rates before the pebble supply diminishes. Exterior to the iceline, planetesimal accretion becomes inefficient due to increasing planetesimal eccentricities, whilst pebble accretion becomes more efficient as the initial proto-embryo masses increase, allowing them to significantly grow before the pebble supply is depleted. Combining both scenarios allows for more massive proto-embryos at larger distances, since the accretion of planetesimals allows pebble accretion to become more efficient, allowing giant planet cores to form at distances upto $10{\, {\rm au}}$. By including more realistic initial proto-embryo and planetesimal sizes, as well as combined accretion scenarios, should allow for a more complete understanding in the beginning to end process of how planets and planetary systems form.
8
Zasada, John C. "Embryo growth in Alaskan white spruce seeds." Canadian Journal of Forest Research 18, no. 1 (January 1, 1988): 64–67. http://dx.doi.org/10.1139/x88-010.
Анотація:
Embryo development in white spruce seeds was studied in five stands in interior Alaska. Cones and seeds were collected at 10- to 14-day intervals starting in mid-July and continuing until just before seed dispersal began. Significant differences were found in embryo development between stands, between trees within stands, and between cones within trees. The four stands at lower elevations produced seeds that had embryos filling 95% or more of the embryo cavity; this percentage was significantly higher than the highest elevation stand where embryos filled about 75% of the embryo cavity at the end of the growing season. Relative cotyledon length was generally greater than 25% in the lower elevation stands and slightly less than 20% in the high elevation stand. Although seed collection can be started when embryos fill 75% of the embryo cavity, the results of this and other studies suggest that collecting seeds when embryos are more mature will result in better quality seeds. Air and soil temperatures and soil moisture levels associated with embryo development are presented.
9
Arkani-Hamed, Jafar, and Boris A. Ivanov. "Shock wave propagation in layered planetary embryos." Physics of the Earth and Planetary Interiors 230 (May 2014): 45–59. http://dx.doi.org/10.1016/j.pepi.2014.03.005.
10
Lambrechts, Michiel, Alessandro Morbidelli, Seth A. Jacobson, Anders Johansen, Bertram Bitsch, Andre Izidoro, and Sean N. Raymond. "Formation of planetary systems by pebble accretion and migration." Astronomy & Astrophysics 627 (July 2019): A83. http://dx.doi.org/10.1051/0004-6361/201834229.
Анотація:
Super-Earths – planets with sizes between the Earth and Neptune – are found in tighter orbits than that of the Earth around more than one third of main sequence stars. It has been proposed that super-Earths are scaled-up terrestrial planets that also formed similarly, through mutual accretion of planetary embryos, but in discs much denser than the solar protoplanetary disc. We argue instead that terrestrial planets and super-Earths have two clearly distinct formation pathways that are regulated by the pebble reservoir of the disc. Through numerical integrations, which combine pebble accretion and N-body gravity between embryos, we show that a difference of a factor of two in the pebble mass flux is enough to change the evolution from the terrestrial to the super-Earth growth mode. If the pebble mass flux is small, then the initial embryos within the ice line grow slowly and do not migrate substantially, resulting in a widely spaced population of approximately Mars-mass embryos when the gas disc dissipates. Subsequently, without gas being present, the embryos become unstable due to mutual gravitational interactions and a small number of terrestrial planets are formed by mutual collisions. The final terrestrial planets are at most five Earth masses. Instead, if the pebble mass flux is high, then the initial embryos within the ice line rapidly become sufficiently massive to migrate through the gas disc. Embryos concentrate at the inner edge of the disc and growth accelerates through mutual merging. This leads to the formation of a system of closely spaced super-Earths in the five to twenty Earth-mass range, bounded by the pebble isolation mass. Generally, instabilities of these super-Earth systems after the disappearance of the gas disc trigger additional merging events and dislodge the system from resonant chains. Therefore, the key difference between the two growth modes is whether embryos grow fast enough to undergo significant migration. The terrestrial growth mode produces small rocky planets on wider orbits like those in the solar system whereas the super-Earth growth mode produces planets in short-period orbits inside 1 AU, with masses larger than the Earth that should be surrounded by a primordial H/He atmosphere, unless subsequently lost by stellar irradiation. The pebble flux – which controls the transition between the two growth modes – may be regulated by the initial reservoir of solids in the disc or the presence of more distant giant planets that can halt the radial flow of pebbles.
11
Nacu, Ana Maria. "The Right to Life. Legal Status of the Human Embryo." European Journal of Law and Public Administration 10, no. 1 (December 21, 2023): 110–24. http://dx.doi.org/10.18662/eljpa/10.1/200.
Анотація:
This paper aims to review the controversial issues in the field of human rights: the status of the human embryo. Since the moment the creation of human embryos in laboratory condition became available, ethical questions continued to arise and emphasize it’s irascible status. During pregnancy the embryo is part of another human being’s body lacking a legal status distinct from that of his mother’s. Defining the right to life and its prime beneficiaries is an important step in gaining a unitary position on a special status of the human embryo. This special legal status derives from the embryo’s recognized potential to become a human being.
12
Cossou, Christophe, Sean N. Raymond, and Arnaud Pierens. "Making systems of Super Earths by inward migration of planetary embryos." Proceedings of the International Astronomical Union 8, S299 (June 2013): 360–64. http://dx.doi.org/10.1017/s1743921313008958.
Анотація:
AbstractUsing N-body simulations with planet-disk interactions, we present a mechanism capable of forming compact systems of hot super Earths such as Kepler 11. Recent studies show that outward migration is common in the inner parts of radiative disks. However we show that two processes naturally tip the balance in favor of inward migration. First the corotation torque is too weak to generate outward migration for planetary embryos less massive than 4M⊕. Second, system of multiple embryos generate sustained non-zero eccentricities that damp the corotation torque and again favor inward migration. Migration and accretion of planetary embryos in realistic disks naturally produce super Earths in resonant chains near the disk inner edge. Their compact configuration is similar to the observed systems.
13
Hargreaves, Cathy L., Cathie B. Reeves, Jens I. Find, Keiko Gough, Puthiyaparambil Josekutty, Dolina B. Skudder, Susan A. van der Maas, et al. "Improving initiation, genotype capture, and family representation in somatic embryogenesis of Pinus radiata by a combination of zygotic embryo maturity, media, and explant preparation." Canadian Journal of Forest Research 39, no. 8 (August 2009): 1566–74. http://dx.doi.org/10.1139/x09-082.
Анотація:
The principal aim of this investigation was to improve somatic embryogenesis initiation and to enhance representation of families and genotypes within those families of Pinus radiata D. Don. A total of 19 open-pollinated seed families, many with unrelated and weakly related parents, were tested. Optimum stage of cone maturity for initiation success was tested by five collections made at 1 week intervals, spanning the developmental period from pro-embryo to cotyledonary embryos. Two media were compared; embryo-development media (EDM6) and a modified Litvay medium (Glitz). Two zygotic embryo explant-preparation techniques were tested; embryos with retained megagametophytes and excised embryos. Proliferating embryogenic tissues were obtained from all four treatments (2850 explants per treatment, 570 per collection time) for the 19 families. The best initiation rates were achieved with a combination of Glitz medium with excised zygotic embryos, with 55% of explants from all collections and all families combined giving rise to proliferating embryogenic tissue. At the optimal collection time for each of the families, this treatment gave a range of 47%–97% initiation success with an average of 70% per family.
14
DAMETTO, Gracie, Deirdre ZANDER-FOX, Nicole MCPHERSON, Kelton TREMELLEN, and Leanne PACELLA-INCE. "Cell Number on Day 3 of Embryo Development is Associated with Ploidy and Pregnancy Rates." Fertility & Reproduction 04, no. 03n04 (September 2022): 201. http://dx.doi.org/10.1142/s2661318222741121.
Анотація:
Selection of a blastocyst for transfer is based on day5/6 morphology with day3 morphology only used if two blastocysts are equal in quality. Day3 assessments are based on cell number and fragmentation with embryos that are developmentally advanced ([Formula: see text]10 cells) being downgraded. After extended development, if [Formula: see text]10 cell embryos are the best quality they are selected for transfer. Thus, the aim of this study was to determine if cell number on day3 has an impact on embryo fate, euploidy rates and pregnancy rates. Data was retrospectively analysed from 269 women (average age 35.7) undergoing stimulated IVF treatment. Embryos were allocated to one of four categories based on day3 morphological score [Formula: see text]6 cells, 7-9 cells, 10-12 cells and [Formula: see text]13 cells. Results were correlated with embryo fate (vitrification/transfer) and pregnancy rates. After extended culture embryos with [Formula: see text]13 cells on day 3 were mostly likely to have undergone a fresh transfer (28.1%, p[Formula: see text]0.05) compared with embryos with 7-9 cells and 10-12 cells (13.7% and 14.0%, respectively). Embryos with [Formula: see text]6 cells were least likely to be transferred (5.2%) and vitrified (7.1%). Further, embryos with [Formula: see text]6 cells had the lowest pregnancy rate (12.5%) compared with all other groups (p[Formula: see text]0.05). No differences were observed for embryos with 7-9 cells, 10-12 cells and [Formula: see text]13 cells for vitrification rates (42.3%, 40.5% and 35.1%, respectively) or pregnancy rates (33.5%, 43.5% and 45.8%, respectively). Interestingly, the incidence of euploid embryos was increased in [Formula: see text]13 cell embryos (70.0%, p[Formula: see text]0.05) compared with [Formula: see text]6 cells, 7-9 cells and 10-12 cells (52.0%, 42.6% and 52.5%, respectively). Results from this study provide evidence that a review on cleavage stage embryo grading protocols which currently downgrades developmentally advanced embryos [Formula: see text]10 cells is warranted as these embryos do not appear to have a negative impact on pregnancy rates and can result in some of the best clinical outcomes.
15
Kurz, Mimi L., Dane R. Roberts, Barry S. Flinn, and William E. Vidaver. "A morphological and biochemical analysis of embryo maturation during yellow cypress seed development." Canadian Journal of Forest Research 24, no. 3 (March 1, 1994): 431–41. http://dx.doi.org/10.1139/x94-059.
Анотація:
Embryo maturation in yellow cypress (Chamaecyparisnootkatensis (D. Don) Spach) seeds was studied at the morphological, anatomical, and biochemical level over the second and third seasons of seed development. Monthly cone collections were made from six open-pollinated families from two seed orchards. The average number of seeds and embryos per cone for each family was 8.8 and 4.6, respectively. Sixty to 70% of those embryos harvested from early collection dates (December 1988–March 1989) were precotyledonary (stages 1 and 2), with an average length of 0.5 mm. By April 1989 a distinct shift in the proportion of precotyledonary (stages 1 and 2) to late cotyledonary (stages 5 and 6) embryos was observed. The frequency of late cotyledonary (stages 5 and 6) embryos was 100% by August 1989 of the third growing season and averaged 2.5 mm in overall size. Moisture loss and dry weight accumulation were still progressing at the time of seed dispersal and may suggest embryo immaturity. Anatomical studies revealed protein and lipid bodies were present as early as the stage 1 embryo and became increasingly abundant during maturation. The major storage proteins isolated from protein bodies of embryo tissues had apparent molecular masses of 37, 36, 35, 34, 28, 26, and 24 kDa. Based on their solubility characteristics, the proteins were identified as buffer-soluble albumins that contained intermolecular disulfide linkages. Storage proteins were detected in early stage embryos and increased in abundance throughout maturation. Upon germination, storage proteins slowly declined to low levels by 16 and 20 days postgermination. The evidence suggests that yellow cypress embryos may be immature at the time of seed dispersal and this immaturity may contribute to the poor germination exhibited by this species.
16
Morbidelli, A., C. Jacob, and J. M. Petit. "Planetary Embryos Never Formed in the Kuiper Belt." Icarus 157, no. 1 (May 2002): 241–48. http://dx.doi.org/10.1006/icar.2002.6832.
17
STOCK-MYER, Sharyn E. "Mosaicism in Human Embryos: What Do We Know?" Fertility & Reproduction 04, no. 03n04 (September 2022): 120. http://dx.doi.org/10.1142/s2661318222740322.
Анотація:
Preimplantation Genetic Testing for Aneuploidy (PGT-A) involves performing aneuploidy testing on the small number of cells biopsied from a preimplantation embryo. It is well established that aneuploidy is a common cause of implantation failure and miscarriage. In an ideal world, a measure of the chromosome status of the cells from the embryo would produce a highly specific result that would predict the fate of that embryo. One of the difficulties with PGT-A however, has been putative chromosomal mosaicism present in a proportion of tested embryos. Chromosome mosaicism became more widely reported following the use of Next Generation Sequencing (NGS) as a tool for performing PGT-A. This was due to the higher dynamic range of the NGS profiles that made mosaicism in the trophectoderm biopsy more visible. Around this same time the first study was published that followed the transfer of 18 mosaic embryos, resulting in the birth of six healthy babies ( Greco et al 2015 ). Since then, several publications have described the results of mosaic embryo transfers, including the work by Viotti et al 2021 which summarised the results of transferring 1000 mosaic embryos. These studies have the common theme that a mosaic embryo result does not clearly predict a negative pregnancy outcome, unlike a uniform aneuploid result. However, it may predict a reduced chance of pregnancy, and an increased chance of miscarriage, depending on the type of mosaicism. Reassuringly, a mosaic result in an embryo also does not seem to indicate a higher chance of having a baby with an abnormality than euploid embryos. Chromosomally mosaic embryos should not be discarded and should be considered for use with appropriate counselling of the patients.
18
Beaugé, C., and S. J. Aarseth. "N-body simulations of planetary formation." Monthly Notices of the Royal Astronomical Society 245, no. 1 (July 1, 1990): 30. http://dx.doi.org/10.1093/mnras/245.1.30.
Анотація:
Summary We have performed numerical simulations of the last stage of terrestrial planetary formation using an N-body code similar to that of Lecar & Aarseth. An improved treatment of collisions has been applied, which allows fragmentation and cratering, as well as accretion. Initial models consist of 200 bodies of total mass 2.3 x 1028 g, distributed in a two-dimensional ring of size 1 au with initial circular orbits about the Sun. Planetary embryos begin to form by accretion in the early stages when the relative velocities are small. This growth is slowed down by the fragmentation process, which occurs when the typical eccentricities have reached ⋍ 0.04. Eventually, a small number of massive embryos emerge, and subsequently accrete nearly all the fragments. Final configurations of three different models yield four principal bodies with moderate eccentricities on a time-scale of ⋍ 5 x 105 yr (equivalent to ∽ 108 yr in a 3D model), and the corresponding parameters are qualitatively similar to those of the terrestrial planets.
19
Tanaka, Atsushi, Motoi Nagayoshi, Yasuho Yanagihara, Izumi Tanaka, Takako Akahoshi, Megumi Araki, Nao Urabe, Akihiro Tanaka, and Tatsuya Sato. "Wisdom of Freezing All Valuable Embryos." Fertility & Reproduction 03, no. 04 (December 2021): 136–42. http://dx.doi.org/10.1142/s2661318221500201.
Анотація:
Background: It is controversial whether that “Freeze-only” strategy is superior to Fresh embryo transfer in ART patients with normal ovarian response. There are two reasons supporting a “Freeze-only” strategy. One is that frozen-thawed embryos are transferred to a more physiologically receptive endometrium. While fresh embryos are transferred to a badly affected one because of controlled-ovarian stimulations, which cause the discordant development of the endometrium, when thawed-frozen embryos are transferred in a subsequent cycle the endometrium is not affected by high estrogen levels. The other reason is the big difference in cryopreservation and stimulation techniques. Methods: We investigated the annual ART reports in Japan from 1992 to 2018, and our clinical outcomes of frozen-thawed embryo transfers and fresh embryo transfers from 2015 to 2019. This enabled the assessment of the survival rate of frozen blastocyst by Cryotop safety kit after thawing in four different clinics. We compared the outcomes of frozen embryo transfer (FroET) to fresh embryo transfer. Results: The proportion of birth in Japan in the study interval found that FroET was responsible for 86.7% of births, compared to 13.3% of births resulting from fresh embryo transfers after IVF or intracytoplasmic sperm injection (ICSI). Clinical outcome of FroET in our clinic was significantly higher than that of fresh embryo transfer regardless of maternal age and number of collected oocytes. Average survival rate of frozen blastocyst by Cryotop safety kit after thawing in four clinics was over 95%. Conclusions: We believe that “Freeze-only high-quality blastocysts” is superior to fresh embryo transfer in terms of clinical outcome, at least when compared to historical results.
20
Singh, Neeta, Garima Patel, Monika Saini, and Ankita Sethi. "Transfer or not to transfer? a medical dilemma." International Journal of Reproduction, Contraception, Obstetrics and Gynecology 11, no. 9 (August 29, 2022): 2569. http://dx.doi.org/10.18203/2320-1770.ijrcog20222335.
Анотація:
Morphological assessment predominantly determines the quality of embryos although, several methods are available for it. Dilemma to transfer arises when clinicians are left with mere poor grade embryos. This case report encompasses a case of 37 years primary infertile female managed with GnRH antagonist cycle for tubal factor infertility. Post ovarian stimulation and ovum pickup, only two 4 celled grade-C embryos were available for transfer. Reluctantly the embryo was transferred, but fortunately resulted in a healthy live intrauterine pregnancy. This case report questions the aptness of the current methods to determine embryo quality and also enlightens whether the ethical or medical conundrum holds true regarding relation between embryo quality and chances of a fruitful pregnancy.
21
LAZZARO, Leah, Martin HEALEY, and Tiki OSIANLIS. "Multinucleation in the Two-Cell Stage Embryo Matters." Fertility & Reproduction 04, no. 03n04 (September 2022): 167. http://dx.doi.org/10.1142/s2661318222740796.
Анотація:
Background: Blastomere multinucleation (MN), defined as the presence of more than one nucleus per cell, in the cleavage-stage embryo, is a well-documented phenomenon 1 . This nuclear anomaly has become more visible with the introduction of time-lapse incubation and an understanding of the potential outcomes of these embryos is necessary to inform decision-making and manage patient expectations. Aim: To determine rates of blastocyst utilisation and euploidy for embryos with MN at the two-cell stage (MN2) in comparison to mononucleated and binucleated embryos. Method: A retrospective analysis was performed at a single IVF unit, of embryos with known two-cell nucleation status from October 2019 to March 2021. Blastomere nucleation was assessed, via time-lapse monitoring (EmbryoScope; UnisenseFertiliTech), and categorised as mononucleate, binucleate or MN in all fertilised oocytes. Blastocyst utilisation rates (number of embryos frozen+transferred/number of oocytes fertilised) were compared together with euploidy rates in embryos that had preimplantation genetic testing for aneuploidy. Outcomes were modelled using multilevel logistic regression to allow for lack of independence between embryos when grouped by patient and cycle, and adjusted for patient age. Results: Of the 4388 embryos included in this study, 68% were mononucleated, 14% binucleated and 18% MN. The likelihood of embryos becoming usable blastocysts based on nucleation status at the two-cell stage for mononucleated, binucleated and MN were 63%, 55%(p<0.001) and 35%(p<0.001) respectively. The euploidy rates for mono-, bi- and MN were 45%, 38%(p=0.09) and 31%(p=0.004) respectively. Predictive modeling, with adjusting for age, showed that a mononucleate two-cell embryo has 44% likelihood of becoming a euploid blastocyst, binucleate 36% and MN 28%. Conclusion: There was a clear reduction in rate of blastocyst utilisation and euploidy in binucleate and a further reduction in MN two-cell stage embryos, in comparison to mononucleate embryos, which should preferentially be prioritised for transfer.
22
Bitsch, Bertram, Andre Izidoro, Anders Johansen, Sean N. Raymond, Alessandro Morbidelli, Michiel Lambrechts, and Seth A. Jacobson. "Formation of planetary systems by pebble accretion and migration: growth of gas giants." Astronomy & Astrophysics 623 (March 2019): A88. http://dx.doi.org/10.1051/0004-6361/201834489.
Анотація:
Giant planets migrate though the protoplanetary disc as they grow their solid core and attract their gaseous envelope. Previously, we have studied the growth and migration of an isolated planet in an evolving disc. Here, we generalise such models to include the mutual gravitational interaction between a high number of growing planetary bodies. We have investigated how the formation of planetary systems depends on the radial flux of pebbles through the protoplanetary disc and on the planet migration rate. Our N-body simulations confirm previous findings that Jupiter-like planets in orbits outside the water ice line originate from embryos starting out at 20–40 AU when using nominal type-I and type-II migration rates and a pebble flux of approximately 100–200 Earth masses per million years, enough to grow Jupiter within the lifetime of the solar nebula. The planetary embryos placed up to 30 AU migrate into the inner system (rP < 1AU). There they form super-Earths or hot and warm gas giants, producing systems that are inconsistent with the configuration of the solar system, but consistent with some exoplanetary systems. We also explored slower migration rates which allow the formation of gas giants from embryos originating from the 5–10 AU region, which are stranded exterior to 1 AU at the end of the gas-disc phase. These giant planets can also form in discs with lower pebbles fluxes (50–100 Earth masses per Myr). We identify a pebble flux threshold below which migration dominates and moves the planetary core to the inner disc, where the pebble isolation mass is too low for the planet to accrete gas efficiently. In our model, giant planet growth requires a sufficiently high pebble flux to enable growth to out-compete migration. An even higher pebble flux produces systems with multiple gas giants. We show that planetary embryos starting interior to 5 AU do not grow into gas giants, even if migration is slow and the pebble flux is large. These embryos instead grow to just a few Earth masses, the mass regime of super-Earths. This stunted growth is caused by the low pebble isolation mass in the inner disc and is therefore independent of the pebble flux. Additionally, we show that the long-term evolution of our formed planetary systems can naturally produce systems with inner super-Earths and outer gas giants as well as systems of giant planets on very eccentric orbits.
23
Merkle, S. A., and H. E. Sommer. "Somatic embryogenesis in tissue cultures of Liriodendrontulipifera." Canadian Journal of Forest Research 16, no. 2 (April 1, 1986): 420–22. http://dx.doi.org/10.1139/x86-077.
Анотація:
Tissue cultures of yellow poplar (Liriodendrontulipifera L.) were initiated from immature and mature zygotic embryos. Nodular embryogenic callus developed from a low percentage of the cultures initiated from immature embryos on solid media supplemented with 2,4-dichlorophenoxyacetic acid, 6-benzyladenine, and casein hydrolysate. Embryoids differentiated from these culture lines within 1 month following transfer of embryogenic callus to hormone-free solid media. Although most embryoids appeared abnormal, embryoids with well-formed cotyledons and radicles were capable of developing into normal plantlets.
24
Bitsch, Bertram, Trifon Trifonov, and Andre Izidoro. "The eccentricity distribution of giant planets and their relation to super-Earths in the pebble accretion scenario." Astronomy & Astrophysics 643 (November 2020): A66. http://dx.doi.org/10.1051/0004-6361/202038856.
Анотація:
Observations of the population of cold Jupiter planets (r >1 AU) show that nearly all of these planets orbit their host star on eccentric orbits. For planets up to a few Jupiter masses, eccentric orbits are thought to be the outcome of planet–planet scattering events taking place after gas dispersal. We simulated the growth of planets via pebble and gas accretion as well as the migration of multiple planetary embryos in their gas disc. We then followed the long-term dynamical evolution of our formed planetary system up to 100 Myr after gas disc dispersal. We investigated the importance of the initial number of protoplanetary embryos and different damping rates of eccentricity and inclination during the gas phase for the final configuration of our planetary systems. We constrained our model by comparing the final dynamical structure of our simulated planetary systems to that of observed exoplanet systems. Our results show that the initial number of planetary embryos has only a minor impact on the final orbital eccentricity distribution of the giant planets, as long as the damping of eccentricity and inclination is efficient. If the damping is inefficient (slow), systems with a larger initial number of embryos harbour larger average eccentricities. In addition, for slow damping rates, we observe that scattering events are already common during the gas disc phase and that the giant planets that formed in these simulations match the observed giant planet eccentricity distribution best. These simulations also show that massive giant planets (above Jupiter mass) on eccentric orbits are less likely to host inner super-Earths as they get lost during the scattering phase, while systems with less massive giant planets on nearly circular orbits should harbour systems of inner super-Earths. Finally, our simulations predict that giant planets are not single, on average, but they live in multi-planet systems.
25
Silsbee, Kedron, and Scott Tremaine. "Producing Distant Planets by Mutual Scattering of Planetary Embryos." Astronomical Journal 155, no. 2 (January 18, 2018): 75. http://dx.doi.org/10.3847/1538-3881/aaa19b.
26
Morris, Melissa A., Aaron C. Boley, Steven J. Desch, and Themis Athanassiadou. "CHONDRULE FORMATION IN BOW SHOCKS AROUND ECCENTRIC PLANETARY EMBRYOS." Astrophysical Journal 752, no. 1 (May 23, 2012): 27. http://dx.doi.org/10.1088/0004-637x/752/1/27.
27
Quillen, Alice C., Alessandro Morbidelli, and Alex Moore. "Planetary embryos and planetesimals residing in thin debris discs." Monthly Notices of the Royal Astronomical Society 380, no. 4 (September 3, 2007): 1642–48. http://dx.doi.org/10.1111/j.1365-2966.2007.12217.x.
28
Rafikov, R. R. "The Growth of Planetary Embryos: Orderly, Runaway, or Oligarchic?" Astronomical Journal 125, no. 2 (February 2003): 942–61. http://dx.doi.org/10.1086/345971.
29
Šrámek, Ondřej, Laura Milelli, Yanick Ricard, and Stéphane Labrosse. "Thermal evolution and differentiation of planetesimals and planetary embryos." Icarus 217, no. 1 (January 2012): 339–54. http://dx.doi.org/10.1016/j.icarus.2011.11.021.
30
Becwar, M. R., R. Nagmani, and S. R. Wann. "Initiation of embryogenic cultures and somatic embryo development in loblolly pine (Pinustaeda)." Canadian Journal of Forest Research 20, no. 6 (June 1, 1990): 810–17. http://dx.doi.org/10.1139/x90-107.
Анотація:
Immature zygotic embryo explants (isolated or with intact megagametophytes) from 10 loblolly pine (Pinustaeda L.) clones (7-34, 7-56, 11-9, 11-16, 11-25, 10-1003, 10-1007, 10-1011, 10-1018, and 10-1019) were surveyed for their potential to form embryogenic tissue from the suspensor region of zygotic embryos. After over 14 000 explants were cultured, embryogenic cultures were initiated from explants of 8 of the 10 clones; only explants from clones 11-25 and 10-1019 were not responsive. Embryogenic tissue was initiated from zygotic embryos with intact megagametophytes on MSG basal medium with no exogenous plant growth regulators or with 2–5 mg/L 2,4-dichlorophenoxy acetic acid (2,4-D) and 0–1 mg/L N6-benzyladenine (BA). The highest initiation frequency (5%) was obtained from isolated zygotic embryos of clone 7-34 less than 0.5 mm in length just prior to cotyledon primordia development on DCR basal medium with 3 mg/L 2,4-D and 0.5 mg/L BA. Two types of embryogenic cultures were maintained on medium with 2,4-D and BA: (i) those that contained pre-embryonal masses of cells interspersed with unaggregated suspensorlike cells, but which rarely contained well-formed somatic embryos, and (ii) those that frequently contained well-formed somatic embryos. Somatic embryo development from both types of cultures progressed to a precotyledonary stage on medium with 2.6 mg/L abscisic acid.
31
Ngo, Henry, Martin J. Duncan, and Harold F. Levison. "LIPAD Simulations of Giant Planet Core Formation." Proceedings of the International Astronomical Union 8, S299 (June 2013): 171–72. http://dx.doi.org/10.1017/s1743921313008259.
Анотація:
AbstractWe present some preliminary results from our investigation of giant planetary core formation using numerical simulations with the Lagrangian Integrator for Planetary Accretion and Dynamics (LIPAD) by Levison et al. (2012). LIPAD couples dynamics with collisional evolution, including fragmentation. We start with a cold planetesimal disk using particles of a few kilometres in size. Our simulations show growth from kilometre-sized planetesimals to several Earth-mass sized embryos (tens of thousands of kilometers) can occur. However, these embryos may not be large enough to start runaway gas accretion necessary to build the envelopes of gas giant planets.
32
PAGE, Stephen. "No, They’re Mine: Who Owns the Embryos?" Fertility & Reproduction 04, no. 03n04 (September 2022): 157. http://dx.doi.org/10.1142/s2661318222740693.
Анотація:
Background: Disputes between couples who have stored embryos are becoming more and more common. Where has the law come to with who can own or use the embryos- and how can a dispute be resolved to make it clear to a clinic as to who can and cannot use the embryo? Aim: To set out for practitioners who owns the embryos, or at least the right to possess them- and practical ways to resolve disputes, so that it is clear who has the right to store, use, and discard, and who does not. Method: A paper would be prepared setting out the law, along with practical tips. Results: As above. Conclusion: Clarity will be provided to practitioners so that they are aware of issues that arise when separating couples have embryos in storage- and can act protectively of themselves and of the embryos.
33
BEKAERT, Bieke, Annekatrien BOEL, Lisa DE WITTE, Mina POPOVIC, Panagiotis STAMATIADIS, Gwenny COSEMANS, Lise TORDEURS та ін. "Correcting a PLCζ Mutation in the Human Germ Line to Overcome Hereditary Infertility". Fertility & Reproduction 04, № 03n04 (вересень 2022): 89. http://dx.doi.org/10.1142/s2661318222740012.
Анотація:
Human germline gene correction by CRISPR/Cas9 holds great promise to eliminate transmission of genetic mutations. Recent studies have however made troublesome observations of mosaicism (the occurrence of multiple genetic events in one embryo) and loss-of-heterozygosity (LOH, loss of the allele of one of the parents), the latter being either caused by inter-homologue homologous recombination (IH-HR) or chromosome loss events. As a proof-of-concept we targeted a heterozygous base pair substitution mutation in PLCZ1, leading to subfertility. After CRISPR/Cas9 editing, we detected in 26% (7/27) of the targeted embryos that originated from mutant sperm only, wild-type alleles upon analysis, which were not obtained by exogenous repair template use. In these seven embryos, we observed a significant amount of LOH events (14%) that spanned regions beyond the PLCZ1 gene, but did not stretch the complete analysed region, pointing to IH-HR, next to a large proportion of samples (57%) showing potential but non-detectable (i.e. below the resolution of our assay) LOH. In addition, a minority of embryos (29%) showed LOH across the whole analysed region. Remarkably, also 10% of the embryos originating from wild-type sperm showed LOH events, underscoring the subpar specificity of the CRIPSR/Cas9 system. Single-cell analysis demonstrated mosaicism in 80% (4/5) of the targeted embryos, warranting caution for trophectoderm biopsy interpretation in future human embryo editing attempts. Lastly, a correction rate of 75% was observed in our single-cell data which illustrates that the correction rate was possibly underestimated when looking at the whole-embryo level.
34
Nagmani, R., A. M. Diner, and G. C. Sharma. "Somatic embryogenesis in longleaf pine (Pinuspalustris)." Canadian Journal of Forest Research 23, no. 5 (May 1, 1993): 873–76. http://dx.doi.org/10.1139/x93-115.
Анотація:
Isolated zygotic embryos and female gametophytes containing zygotic embryos were cultured on MSG and DCR basal media, supplemented with three different carbon sources added individually to the medium at four levels each. The media also contained various levels of 2,4-dichlorophenoxy acetic acid (2,4-D) and N6-benzyladenine (BA). Embryogenic tissue extruded from female gametophytes during 4 weeks in culture on media containing either glucose or maltose or sucrose. Embryogenic tissue initiation was most frequently from explants collected on July 14, 1992, when the zygotic embryos within the female gametophytes were precotyledonary. A total of 33 embryogenic cultures were initiated from 944 explants cultured. One of 192 explants cultured on basal media with no growth regulators produced embryogenic tissue. The embryogenic tissue showed numerous somatic embryos at stages 1 and 2 of development, corresponding to their zygotic embryo counterparts.
35
Johansen, Anders, Mordecai-Mark Mac Low, Pedro Lacerda, and Martin Bizzarro. "Growth of asteroids, planetary embryos, and Kuiper belt objects by chondrule accretion." Science Advances 1, no. 3 (April 2015): e1500109. http://dx.doi.org/10.1126/sciadv.1500109.
Анотація:
Chondrules are millimeter-sized spherules that dominate primitive meteorites (chondrites) originating from the asteroid belt. The incorporation of chondrules into asteroidal bodies must be an important step in planet formation, but the mechanism is not understood. We show that the main growth of asteroids can result from gas drag–assisted accretion of chondrules. The largest planetesimals of a population with a characteristic radius of 100 km undergo runaway accretion of chondrules within ~3 My, forming planetary embryos up to Mars’s size along with smaller asteroids whose size distribution matches that of main belt asteroids. The aerodynamical accretion leads to size sorting of chondrules consistent with chondrites. Accretion of millimeter-sized chondrules and ice particles drives the growth of planetesimals beyond the ice line as well, but the growth time increases above the disc lifetime outside of 25 AU. The contribution of direct planetesimal accretion to the growth of both asteroids and Kuiper belt objects is minor. In contrast, planetesimal accretion and chondrule accretion play more equal roles in the formation of Moon-sized embryos in the terrestrial planet formation region. These embryos are isolated from each other and accrete planetesimals only at a low rate. However, the continued accretion of chondrules destabilizes the oligarchic configuration and leads to the formation of Mars-sized embryos and terrestrial planets by a combination of direct chondrule accretion and giant impacts.
36
Anderson, Erika D., and John N. Owens. "Embryo development, megagametophyte storage product accumulation, and seed efficiency in Taxus brevifolia." Canadian Journal of Forest Research 31, no. 6 (June 1, 2001): 1046–56. http://dx.doi.org/10.1139/x01-040.
Анотація:
Taxus brevifolia Nutt. has a reduced ovulate structure that consists of a single ovule in a leaf axil instead of a compound ovulate strobilus. Taxus brevifolia on southern Vancouver Island, British Columbia, were studied over three seasons. Proembryos occurred from mid-May to mid-June. They underwent four free nuclear divisions forming 16 nuclei before cellularization. Early embryos were present from mid-May to mid-August. Simple polyembryony was observed up to the massive embryo stage, and differential growth of the embryonal cells was interpreted as incomplete cleavage polyembryony. Mid-embryos were present from mid-June to late August and had a distinct protoderm and focal zone. Late embryos were visible from mid-July onwards. Carbohydrates began accumulating at the early embryo stage, whereas proteins and lipids accumulated in the late embryo stage. The presence of a red aril corresponded to increased amounts of lipid in the megagametophyte cells. Individual seeds matured from July until November. The seed efficiency ranged from 0 to 16% and averaged 5%. Prezygotic loss was the most common fate of ovules, followed by postzygotic loss. Possible causes of this poor seed efficiency are poor pollination success, insect damage, or light limitation.
37
Merkle, S. A., A. T. Wiecko, and B. A. Watson-Pauley. "Somatic embryogenesis in American chestnut." Canadian Journal of Forest Research 21, no. 11 (November 1, 1991): 1698–701. http://dx.doi.org/10.1139/x91-235.
Анотація:
Cultures were initiated from developing ovules and excised embryos of American chestnut (Castaneadentata (Marsh.) Borkh.), collected from five source trees on three dates during early and middle stages of fruit development. Explants were cultured initially on semisolid induction medium containing 0.25 mg/L benzyladenine and either 6 mg/L naphthaleneacetic acid or 4 mg/L 2,4-dichlorophenoxyacetic acid for 1 or 2 weeks. Then they were either transferred to hormone-free medium or medium with 0.25 mg/L benzyladenine or maintained on the original induction media. Ovules collected from three of the five trees 6 or 7 weeks postanthesis produced embryogenic cultures. Those pulsed for 1 or 2 weeks on auxin-containing medium prior to transfer to media without auxin produced multiple somatic embryos directly from the radicle end of the zygotic embryo. Cultures maintained on auxin-supplemented media initially produced proembryogenic masses, which formed globular and heart-stage embryos as they aged. Transfer of clusters of somatic embryos from auxin-supplemented media to hormone-free medium promoted maturation of embryos to the cotyledon stage.
38
KARASAÇ, Eda Gülsüm. "RIGHT TO LIFE OF FOETAL." Ankara Üniversitesi Hukuk Fakültesi Dergisi 71, no. 3 (October 19, 2022): 1051–97. http://dx.doi.org/10.33629/auhfd.1136762.
Анотація:
The right to life is one of the fundamental rights. There are many moral and legal debates on the right to life of embryos and fetuses. Aside from the debates on whether the embryo/fetus can be considered a human and person, determining the moment when the fetus acquired the legal capacity and personality is important for the legal protection of the embryo/fetus. In addition to the crimes and abortion, with the technological developments in biology, the violations of the right to life of the fetus have increased. Especially with the implementation of assisted reproductive treatment methods, new debates arose about the right to life of IVF embryos. Besides that, genetic diagnostic test applications, spare and research embryos have revealed the importance of determining the legal status of the embryo/fetus. The legal status of the embryo and fetus within the national legislation is still unclear. In the decisions given by the ECHR, it hasn’t reached a definite judgment about when the right to life begins. ECHR, in most of its decisions, didn’t discuss the right to life of the embryo/fetus. When the court found the issue worth discussing, it concluded that the fetus didn’t have the right to life before birth.
39
SOLE, Sally, Elissa WILLATS, Mark GREEN, Luk ROMBAUTS, Darren KATZ, Deirdre ZANDER-FOX, and Fabrizzio HORTA. "Is There an Increased Incidence of Aneuploid Embryos in Cases of Obstructive and Non-Obstructive Azoospermia?" Fertility & Reproduction 04, no. 03n04 (September 2022): 210. http://dx.doi.org/10.1142/s2661318222741212.
Анотація:
Background: Current evidence supports that males with low spermatozoa concentrations, as well as obstructive azoospermia (OA) or non-obstructive azoospermia (NOA), present with high rates of aneuploid spermatozoa. This issue could potentially lead to an increased number of aneuploid embryos in subsequent ICSI cycles using surgically retrieved spermatozoa, however, azoospermia is not routinely considered to be a clinical indication for pre-implantation genetic testing for aneuploidies (PGT-A). Aim: To identify the incidence of aneuploid embryos in PGT-A cycles that used testicular spermatozoa extracted through surgical sperm retrieval (SSR). In addition, whether aneuploidy rates differed between embryos fertilised with SSR compared with ejaculated spermatozoa. Method: A retrospective study of OA and NOA patients who underwent SSR between March 2017 and September 2020 and had PGT-A cycles. Next-generation sequencing was employed to detect embryo aneuploidies. Data were compared and analysed using a chi-square test with PGT-A cycles using ejaculated spermatozoa within the same time-period. Results: A total of 57 males underwent SSR, leading to 68 cycles that included the use of PGT-A. A total of 152 embryos with conclusive results identified there to be 57.2% euploid embryos (87/152) and 38.2% aneuploid embryos (58/152) in the SSR group. In comparison, the ejaculated spermatozoa group resulted in 59.2% (2115/3677) euploid embryos and 35.7% (1312/3677) aneuploid embryos. The incidence of aneuploid embryos (38.2%) in the SSR group was not statistically significant [Odds ratio: 1.11 (0.79-1.56) p=0.53]. Importantly, there were no differences for mean maternal age for both study groups (SSR female partners: 36.7 years; ejaculated spermatozoa female partners: 37.1 years; p>0.1). Conclusion: The current outcomes indicate there is not an increased incidence of aneuploid embryos in PGT-A cycles of men who underwent to SSR compared with men using ejaculated spermatozoa.
40
Kannan, Palanisamy, Veeran Vijaya Kumar, and Rajakumaran Pathmavathi Saralla. "In vitro propagation of threatened therapeutic tree Buchanania lanzan Spreng (Anacardiaceae)." Journal of Drug Delivery and Therapeutics 12, no. 6 (November 15, 2022): 31–37. http://dx.doi.org/10.22270/jddt.v12i6.5784.
Анотація:
Embryo rescue refers to an in vitro technology have been used for propagating plants under in vitro from poorly developed embryos by avoiding embryo abortion. The aim of the present study was to in vitro regeneration of a medicinally wild tree species Buchanania lanzan through embryo rescue method. Isolated immature poorly developed embryo dissected out from de-coded seeds collected from 15 years old trees were cultured an Woody Plant Medium (WPM) was used to test in vitro germination. 100% embryo germination were recorded when the embryos inoculated on the medium supplemented with 1.5 mg/L-1 6-benzylaminopurine (BAP) and 50 mg/L-1 adenine sulphate (AS). Further, a week-old seedling derived explants viz embryo axis and cotyledonary node were selected to study in vitro clonal propagation. On medium augmented with 1.5 mg/L-1 6-benzylaminopurine (BAP) showed maximum mean shoots numbers (4.2±1.80) with 4.0±0.98 cm shoot height were achieved in cotyledonary node. Compare to Kinetin (Kn) BAP was to be better in shooting response and multiple shoot induction. Healthy regenerated shoots was separated from multiple shoots cluster and transferred to a rooting medium containing half strength WP medium fortified with Indole-3-butyric acid (IBA). IBA at 0.5 mg/L-1 showed 90% rooting response and maximum mean roots (4.9±0.98) per shootlet was obtained. The rooted in vitro plantlets were transferred to polythene bags containing autoclaved humus, red soil and farmyard manure (1:1:1 ratio) for acclimation at 25 ± 2 ᵒC. Later, these plantlets were gradually transferred to field condition. About 70% survival rate was recorded after three months period. The protocol developed in the present study was to restore the viable embryos from poorly developed immature embryos and rapid multiplication can help to ex situ conservation of this threatened tree B. lanzan.
Keywords: Woody plant medium, In vitro seedlings, 6-benzylaminopurine, Adenine sulphate, Indole-3-butyric acid
41
Krogstrup, P. "Embryolike structures from cotyledons and ripe embryos of Norway spruce (Piceaabies)." Canadian Journal of Forest Research 16, no. 3 (June 1, 1986): 664–68. http://dx.doi.org/10.1139/x86-116.
Анотація:
Embryos from imbibed ripe seeds and cotyledon expiants of 7-day-old Norway spruce (Piceaabies (L.) Karst.) seedlings produced the early stages of somatic embryogenesis. Using a modified Murashige and Skoog medium, a whitish, glossy callus was induced consisting of translucent cells embedded in a mucilaginous cloudy matrix. This embryogenic callus formed on the surface of explants treated first with N-6-benzyladenine followed by 2,4-dichlorophenoxyacetic acid + 6-furfurylaminopurine (kinetin) + N-6-benzyladenine. Transfer of this callus to media lacking growth regulators resulted in the formation of numerous bipolar embryoids with suspensorlike structures. These embryoids strongly resembled repressed embryos in polyembryonic seeds.
42
Chrenko, Ondřej, Miroslav Brož, and David Nesvorný. "Binary Planet Formation by Gas-assisted Encounters of Planetary Embryos." Astrophysical Journal 868, no. 2 (December 4, 2018): 145. http://dx.doi.org/10.3847/1538-4357/aaeb93.
43
Anderson, Erika D., John N. Owens, Anna M. Colangeli, and John H. Russell. "Challenges facing Chamaecyparis nootkatensis seed orchards: low seed production, pollen-cone abortion, self-pollination, and accelerated embryo development." Canadian Journal of Forest Research 32, no. 8 (August 1, 2002): 1411–19. http://dx.doi.org/10.1139/x02-070.
Анотація:
Seed orchard production of Chamaecyparis nootkatensis (D. Don) Spach seed faces several challenges including low seed production, pollen-cone abortion, self-pollination, and accelerated reproductive development. In a seed orchard study in 1988 and 1989, approximately eight seeds were produced per cone, but only one to three seeds per cone contained viable embryos. Pollen-cone abortion in 21 clones ranged from 6 to 87% in 19891990 and from 0 to 6% in 19901991. A bud mite, identified as Trisetacus chamaecypari Smith, was consistently associated with pollen-cone abortion in two orchard locations. This mite may be the cause or simply a symptom of unhealthy pollen cones. In a pollination study involving wind, self, and cross pollinations on five clones, self-pollinated cones had significantly fewer seeds containing embryos (4%) compared with the other treatments (2833%). Pollen-cone development at a seed orchard occurred in July and August 1990 and was comparable with natural stand phenology. However, embryo development was significantly accelerated, with embryos at a seed orchard substantially larger than embryos at the natural stand at comparable times.
44
LEE, Shaw Ni Amy, Chiou Fen TO, Mei Jing ONG, Rui Shan WONG, and Su Ling YU. "Case Report: Successful Pregnancy and Birth of a Healthy Baby with PGT-A for Woman with Advanced Maternal Age." Fertility & Reproduction 04, no. 03n04 (September 2022): 194. http://dx.doi.org/10.1142/s2661318222741054.
Анотація:
Introduction: The most common cause of failed implantation and miscarriage is embryonic aneuploidy and the risk of aneuploidy increases significantly with increasing maternal age. Pre-implantation genetic testing for aneuploidy (PGT-A) can be an option to improve the prognosis of women with advanced maternal age by extracting 3-5 trophectoderm cells from Day 5 and Day 6 blastocysts for genetic testing. Case History: A 37 years old patient tried to conceive for 5 years was recruited into our PGS research study initiated by Ministry of Health in Singapore. She had 3 previous implantation failure and one miscarriage between 2015-2018. The patient had regular menses every 30-35 days. Antral follicle count was 48 and her husband’s semen analysis was normal with Density 87 million/ml, motility 34% and morphology 4%. Results: Patient underwent an IVF cycle with PGT-A in December 2018 at our IVF Centre. 23 eggs were retrieved, 21 eggs were mature to undergo ICSI and 11 fertilized. The eggs were cultured in EmbryoGen immediately after ICSI and the embryos were transferred to BlastGen on Day 3 for extended culture. A total of 5 embryos were suitable for biopsy, 3 on Day 5 and 2 on Day 6. Embryos were vitrified while waiting for the genetic results. Chromosomal analysis of the biopsied trophectoderm cells was performed using NGS platform. Out of the 5 embryos tested, 2 embryos were euploid, giving 60% aneuploidy rate. One euploid embryo was thawed and transferred in a regulated frozen-thawed cycle in March 2020. The patient became pregnant and delivered a healthy baby boy. She returned in January 2022 to put back the remaining euploid embryo, she was again pregnant. Conclusion: PGT-A for comprehensive chromosome screening in selecting and transferring euploid embryos in assisted reproduction has an immediate impact on implantation, reduces the rate of clinical miscarriages and results in higher live birth rates.
45
Dwapanyin, George, Darren Chow, Tiffany Tan, Nicolas Dubost, Josephine Morizet, Kylie Dunning, and Kishan Dholakia. "Assessing embryo quality with digital holographic microscopy." EPJ Web of Conferences 287 (2023): 03014. http://dx.doi.org/10.1051/epjconf/202328703014.
Анотація:
A low-powered, non-invasive digital holographic microscopic imaging technique for embryo quality assessment is presented. Two groups of 2 cell-stage embryos cultured in media of different lipid concentrations have been characterized with digital holographic microscopy for lipid aggregation. The study suggests refractive index measurements are reflective of the lipid and dry mass content in embryos thus making DHM a prospective label-free diagnostic tool for quality assessments in assisted reproduction.
46
Li, S. L., C. Agnor, and D. N. C. Lin. "Giant impact, planetary merger, and diversity of planetary-core mass." Proceedings of the International Astronomical Union 3, S249 (October 2007): 301–3. http://dx.doi.org/10.1017/s1743921308016736.
Анотація:
AbstractTransit observations indicate a large dispersion in the internal structure among the known gas giants. This is a big challenge to the conventional sequential planetary formation scenario because the diversity is inconsistent with the expectation of some well defined critical condition for the onset of gas accretion in this scenario. We suggest that giant impacts may lead to the merger of planets or the accretion of planetary embryos and cause the diversity of the core mass. By using an SPH scheme, we show that direct parabolic collisions generally lead to the total coalescence of impinging gas giants whereas, during glancing collisions, the efficiency of core retention is much larger than that of the envelope. We also examine the adjustment of the gaseous envelope with a 1D Lagrangian hydrodynamic scheme. In the proximity of their host stars, the expansion of the planets' envelopes, shortly after sufficiently catastrophic impacts, can lead to a substantial loss of gas through Roche-lobe overflow. We are going to examine the possibility that the accretion of several Earth-mass objects can significantly enlarge the planets' photosphere and elevate the tidal dissipation rate over the time scale of 100 Myr.
47
TRUONG, Thi T., Alexandra J. HARVEY, and David K. GARDNER. "Antioxidants in Mouse Embryo Culture and Vitrification Media Maintain an In Vivo Like Gene Expression Profile." Fertility & Reproduction 04, no. 03n04 (September 2022): 162. http://dx.doi.org/10.1142/s2661318222740747.
Анотація:
Background: Embryo culture and cryopreservation causes detrimental effects on blastocyst gene expression. While combined antioxidants (acetyl-L-carnitine/N-acetyl-L-cysteine/[Formula: see text]-lipoic acid (A3)) in culture and vitrification media have beneficial effects on embryo and fetal development, their impact on fetal gene expression has not been assessed. Therefore, the effects of antioxidants on global gene expression were examined from fetal and placental tissue of transferred blastocysts and compared to in vivo derived embryos. Aim: To determine the effect of A3 in culture and vitrification media on mouse blastocyst, fetal and placental gene expression. Method: Embryo transfers were conducted on in vivo flushed blastocysts or blastocysts cultured or vitrified with and without A3. Transcriptional profiles of E14 fetal liver and placental tissue in all groups were quantified using RNAseq and functional analyses (KEGG). Results: Compared to in vivo derived embryos, in vitro culture altered the expression of 3601 fetal liver and 408 placental genes. Functional analysis showed upregulation/enrichment of oxidative phosphorylation and mitochondrial function and activity. Similarly, vitrification led to 2018 liver and 216 placental differentially expressed genes (DEGs). Upregulated KEGG pathways were enriched for cell and tissue development and cell cycle regulation. Down regulated pathways were associated with metabolism and immune response. Interestingly, exposure to A3 during development significantly reduced the number of DEGs with 1855 and 4 identified in liver and placentae respectively with no KEGG pathways identified. Correspondingly, exposure to A3 during vitrification reduced the number of DEGs to 1017 in liver and 206 in placentae. Functional pathway enrichment was similar to embryos vitrified without A3, although with decreased expression. Conclusion: Supplementation with antioxidants reduce the number of DEGs and biological processes altered by in vitro culture and vitrification, in fetal liver and placentae, establishing a more in vivo like gene expression profile which may help maintain the viability of vitrified human embryos.
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Kvaalen, Harald, Ola Gram Daehlen, Anne Tove Rognstad, Borgny Grønstad, and Ulrika Egertsdotter. "Somatic embryogenesis for plant production of Abies lasiocarpa." Canadian Journal of Forest Research 35, no. 5 (May 1, 2005): 1053–60. http://dx.doi.org/10.1139/x05-035.
Анотація:
Seeds of Abies lasiocarpa (Hook.) Nutt. (subalpine fir) were dissected, and the different parts were analyzed for elemental composition. The data were used to design a novel growth medium for initiation of somatic embryogenesis. Embryogenic cultures were initiated from immature zygotic embryos from six open-pollinated families of A. lasiocarpa on three different media. The frequency of initiation was the highest in early to mid-July when the zygotic embryo explants were ca. 0.8 mm long. Thereafter the response declined rapidly. The culture media did not significantly affect the initiation frequencies, but the subsequent growth and culture survival was dependent on the culture medium. On the Schenk Hildebrandt medium, many cultures ceased to grow and died. Several of the decaying cultures were rescued after transfer to one of the new media. Proliferating cultures could be stimulated to produce mature embryos. Of 2510 mature somatic embryos, 212 (8.4%) converted to plants, and 35 plants have grown over two periods.
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Babenkov, Vladimir Y., Arslang I. Khakhlinov, Roman D. Sangadzhiev, Elena Y. Makarova, and Ochir S. Mergulchiev. "Biotechnologies for accelerated reproduction of Kalmyk cattle." RUDN Journal of Agronomy and Animal Industries 18, no. 1 (March 30, 2023): 71–79. http://dx.doi.org/10.22363/2312-797x-2023-18-1-71-79.
Анотація:
In Russia, the number of beef cattle until recently was concentrated mainly in Kalmykia and adjacent regions. However, the lack of purposeful breeding has led to the fact that the purebred livestock of Kalmyk meat breed has significantly decreased and lost its unique qualities. Introduction of embryo transfer biotechnology can solve the problem of restoring breed qualities under the condition of accelerated reproduction of genotyped livestock. The aim of the research was to study Kalmyk breed response to polyovulation considering further increase in transferrable embryo productivity - the main indicator specific to each breed. As the formation of the breed took place in pasture conditions with a pronounced seasonal sexual cycle, there were doubts about the possibility of using embryo transfer technology in any season. The experiments were carried out on Kalmyk cows at Kalmytskoye farm in 2010 and at the Regional Research and Production Center for Reproduction of Farm Animals, Kalmyk State University, in 2022. The results of the study showed that it was better to synchronize sexual hunting using prostaglandins after 3-4 months after calving (May-October). According to the results of immunogenetic testing, 10 breeding cows and 2 breeding bulls were selected as donors. In September-October, in order to test the embryo transfer method in nomadic animal husbandry, the first work was carried out to stimulate poliovulation and obtain embryos from 3 donor cows. A total of 23 embryos and eggs were obtained, 10 of which were suitable for transplantation. Transferrable embryos were frozen on a ZEM-4 software freezer after equilibration in 1.5 M ethylene glycol cryoprotector solution.
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Weidenschilling, S. J. "Accretion of planetary embryos in the inner and outer solar system." Physica Scripta T130 (July 16, 2008): 014021. http://dx.doi.org/10.1088/0031-8949/2008/t130/014021.