Embryo Growth Research Articles

Evaluation of Fertility Success Rate with Simultaneous Transfer of Embryos with Different Qualities in IVF/ICSI Candidates

Background: One of the most important factors in the success of assisted reproductive techniques is the quality of the embryo generated in the laboratory. Whether to transfer only one high-quality embryo or a combination of high- and low-quality embryos is a dilemma. Objectives: The present study reviewed the embryo transfer records of IVF/intra cytoplasmic sperm injection (ICSI) patients in Dezful Infertility Center, Iran, to evaluate the impact of the simultaneous transfer of a low-quality embryo on the growth and implantation of a high-quality embryo and live birth. Methods: This cross-sectional study evaluated the files and records of 802 patients undergoing IVF/ICSI at Dezful Infertility Treatment Center from 2013 to September 2020. The patients were classified into group 1: Patients with the transfer of only one grade A (equal blastomeres without fragmentation) embryo, group 2: Patients with the transfer of two grade A and B (equal blastomeres with slight fragmentation) embryos, group 3: Patients with the transfer of two grade A and C (unequal blastomeres with or without fragmentation) embryos, and group 4: Patients with the transfer of two grade C and B embryos. Results: The mean age of women and men was 32.52 ± 5.10 and 37.59 ± 6.60 years, respectively. Age, duration of infertility, cause of infertility, endometrial diameter, estradiol level, oocyte number, and embryo number had no significant differences between the groups (P > 0.05). Also, the findings indicated no significant differences between the groups in terms of implantation rate, live birth rate, fertility rate, multiple pregnancies rate, and chemical and clinical abortions (P > 0.05). Conclusions: It seems that the simultaneous transfer of embryos with different qualities does not affect the success rate and fertility outcomes in IVF/ICSI candidates.

Expression and Role of PIWI Proteins and piRNAs in Reproduction of Water Buffalo (Bubalus bubalis, Linn.)

High-fertile and productive dairy animals are important to satisfy the growing population's demand. Sire fertility is one of the essential factors that regulate the overall pregnancy rate of dairy herds. However, sire fertility varies from 10 to 90%, suggesting that male fertility largely accounts for varying fertility levels across the herd. Sub-fertile bulls and females should be identified and discarded promptly to improve the dairy herd's productivity. The most dominant factors implicated in culling are poor semen quality, poor semen freezability (<35% post-thaw motility), and poor libido for the bulls and hard breeders for females that cause huge economic loss to the raisers. Understanding the basic mechanism of male and female fertility has undergone tremendous change in recent times owing to the advancement of molecular tools judging the essential molecules responsible for fertility. Presently, a new molecular niche has surfaced in testes, strongly influencing the fertilization potential of spermatozoa. Over the last decade, there has arrived a conclusion that out of several factors, piRNA and PIWI proteins are largely implicated in regulating the vital aspects of fertility and embryogenesis. While this development is advancing in other animals, very limited information is available on PIWI protein and piRNAs in large animals. Except for a few sporadic information on PIWI protein in cattle, very limited information is available on piRNAs and PIWI protein in regulation with buffalo bull fertility and growth of embryos of buffaloes, posting a huge demand for research.

Effects of the neurotoxin β-N-methylamino-L-alanine (BMAA) on the early embryonic development of marine shellfish and fish

The neurotoxin β-N-methylamino-L-alanine (BMAA) produced by cyanobacteria and diatoms can accumulate in diverse aquatic organisms through the food web. In the present study, embryos of mussel Mytilus galloprovincialis (Lamarck, 1819), oyster Magallana gigas (Thunberg, 1793), and marine medaka Oryzias melastigma (McClelland, 1839) were exposed to BMAA dissolved in seawater and monitored for early developmental effects. Results demonstrated that the embryonic development of mussels and oysters were significantly inhibited when BMAA concentrations were above 100 μg BMAA·HCl/L (0.65 µM) and 800 μg BMAA·HCl/L (5.18 µM), respectively. The shell growth of mussel embryos was also markedly inhibited by BMAA ≥ 100 μg BMAA·HCl/L (0.65 µM). Based on the dose-response curves related to the modified malformation rate of embryos, the median effective concentration (EC50) values of mussel (48 h) and oyster (24 h) embryos were 196 μg BMAA·HCl/L (1.27 µM) and 1660 μg BMAA·HCl/L (10.7 μM), respectively. A sustained and dose-dependent decrease in heart rate was apparent in marine medaka embryos at 9-days post fertilization following BMAA exposure. However, no obvious effect on ATP concentration was noted in these marine medaka embryos. The current study contributes to our understanding of the sublethal effects of BMAA on the early embryonic development of marine bivalves and medaka. Further research examining the long-term effects of BMAA on the early development of marine organisms is necessary to determine seawater quality criteria for protection.

SOMATIC EMBRYOGENESIS AND PLANTLET FORMATION FROM LEAF EXPLANTS OF SPONGE GOURD (Luffa aegyptiaca (MILL.) A MEDICINALLY IMPORTANT PLANT

An effective technique for the stimulation of somatic embryogenesis and plantlet regeneration from Leaf explants was developed in the sponge gourd (Luffa aegyptiaca (Mill.), which is significant in the field of medicinal botany. Fast-growing, yellowish nodular callus lines containing somatic embryos were established on an initiation medium supplemented with 2.0 mg/L 2,4-D, 3.0 mg/L 2,4-5-T, and 2.0 mg/L NAA, respectively. Somatic embryos were induced directly from cotyledon explants on Murashige and Skoog's (MS) medium fortified with different concentrations of 2,4- Dichlorophenoxyacetic acid, 2,4,5-trich On MS medium that was supplemented with 2.0 mg/L2,4-D and 1.5 mg/L TDZ, as well as 3.0 mg/L2,4-D and 2.0 mg/L BAP, embryo growth and good maturation were successfully accomplished. On an MS medium containing 2.0 mg/L TDZ and 2.0 mg/L NAA (-Naphthalene acetic acid), the well-formed embryos germinated into full plantlets and became plantlets. NAA stands for -Naphthalene acetic acid. The plants that had been regenerated were first transplanted into plastic cups and then into pots for maturation. After that, they were moved to soil and developed to maturity with an 80% survival rate, and the tissue culture-reared plants produced viable seeds.

The Effect of Line and Age on The Egg External Characteristics of Japanese Quail

External egg traits like egg length, breadth, shape index, volume and surface area play important roles for egg hatching, embryo growth, and chick survival. 313 fertilized eggs were collected from three genetic lines of Japanese quail named (white, brown, and gray) in four collected ages (57, 64, 71, and 78) days. After collecting the traits were measured by using electronic balance (0.001gm.) sensitivity, and caliper vernier (0.01 mm.). The data show significant differences between some traits and some of them differ with the age of birds and the interaction between the genetic lines and age of collecting eggs. Our results conclude there were significant differences between the three genetic lines on egg external traits and between the collecting age and their infarctions. May its helpful for future studies to establish lines special for egg production, or to make studies on molecular levels.

An active glutamine/α-ketoglutarate/HIF-1α axis prevents pregnancy loss by triggering decidual IGF1+GDF15+NK cell differentiation.

Deficiency of decidual NK (dNK) cell number and function has been widely regarded as an important cause of spontaneous abortion. However, the metabolic mechanism underlying the crosstalk between dNK cells and embryonic trophoblasts during early pregnancy remains largely unknown. Here, we observed that enriched glutamine and activated glutaminolysis in dNK cells contribute to trophoblast invasion and embryo growth by insulin-like growth factor-1 (IGF-1) and growth differentiation factor-15 (GDF-15) secretion. Mechanistically, these processes are dependent on the downregulation of EGLN1-HIF-1α mediated by α-ketoglutarate (α-KG). Blocking glutaminolysis with the GLS inhibitor BPTES or the glutamate dehydrogenase inhibitor EGCG leads to early embryo implantation failure, spontaneous abortion and/or fetal growth restriction in pregnant mice with impaired trophoblast invasion. Additionally, α-KG supplementation significantly alleviated pregnancy loss mediated by defective glutaminolysis in vivo, suggesting that inactivated glutamine/α-ketoglutarate metabolism in dNK cells impaired trophoblast invasion and induced pregnancy loss.

Microplastics of different shapes increase seed germination synchrony while only films and fibers affect seed germination velocity

Microplastics enter the soil in a variety of shapes and polymer types altering soil properties with known consequences for plant growth. However, the effects of a range of different microplastic shapes and types on seed germination are mostly unknown. Here, we established a glasshouse experiment that included 12 microplastic types representing different shapes (fibers, films, foams and fragments) and polymers, and mixed each of them with soil at a concentration of 0.4% (w/w). Fifty seeds of Daucus carota were sown and monitored for 49 days to evaluate different germination parameters. Our results showed that microplastic films and fibers decrease seed germination velocity as they may affect soil water status, likely interfering with different phases of seed germination: Seeds may imbibe toxic microplastic leachates, and be affected by a physical blockage; testa rupturing may be delayed as this also depends on water uptake. Microplastic toxic leachates may affect activity of enzymes key for seed germination, and delay embryo growth and radicle emergence. Microplastics, irrespective of their shape and polymer type, increase synchrony of seed germination, which might be linked with microplastics exerting a mild stress on seeds. The final percentage of germination was not affected by microplastics in soil, implying that microplastics did not affect seed viability. Our results showed that microplastics affect seed germination mainly as a function of their shape.

Pengaruh Suhu Inkubasi Terhadap Profil Ekspresi Gen Determinasi Seks Tukik Lepidochelys olivacea

Sex determination in turtles is not only based on genotype, but also depends on the incubation temperature. In addition, sex differentiation takes place during the thermosensitive period (TSP). This review article aims to examine the effect of incubation temperature on the expression profile of the sex determination gene for tortoises. Fertile eggs are incubated at two temperatures, namely the feminine temperature (30-33 ° C), and the masculine temperature (26-27 ° C). The results of bioreproduction and phenotype measurements of hatchlings, namely, embryo growth, incubation time, morphometrics, and locomotor performance of hatchlings were analyzed by regression analysis and Student's t test. The results of analysis from several literatures showed that the expression of aromatase and Rspond 1 genes (which play a role in ovarian differentiation) after TSP from incubated embryos at a higher feminine temperature and different from the masculine temperature. Regarding bioreproduction, the incubation period at the feminine temperature is shorter than the masculine temperature. Likewise embryos grow more rapidly at feminine temperatures. Incubation at feminine temperature had a significant effect on the phenotype of hatchlings, namely carapace width, plastron length and width, long flipper and hind arms, long neck, and flipper swing frequency.

ABA biosynthesis gene OsNCED3 contributes to preharvest sprouting resistance and grain development in rice.

Preharvest sprouting (PHS) is an unfavorable trait in cereal crops and causes serious yield loss. However, the molecular mechanism underlying PHS remains largely elusive. Here, we identified a member of 9-cis-epoxycarotenoid dioxygenase family, OsNCED3, which regulates PHS and grain development in rice (Oryza sativa L.). OsNCED3 encodes a chloroplast-localized abscisic acid(ABA) biosynthetic enzyme highly expressed in the embryo of developing seeds. Disruption of OsNCED3 by CRISPR/Cas9-mediated mutagenesis led to a lower ABA and higher gibberellic acid(GA) levels (thus a skewed ABA/GA ratio) in the embryo, promoting embryos growth and breaking seed dormancy before seed maturity and harvest, thus decreased seed dormancy and enhanced PHS in rice. However, the overexpression of OsNCED3 enhanced PHS resistance by regulating proper ABA/GA ratio in the embryo. Intriguingly, the overexpression of OsNCED3 resulted in increased grain size and weight, whereas the disruption of OsNCED3 function decreased grain size and weight. Nucleotide diversity analyses suggested that OsNCED3 may be selected during japonica populations adaptation of seed dormancy and germination. Taken together, we have identified a new OsNCED regulator involved rice PHS and grain development, and provide a potential target gene for improving PHS resistance and grain development in rice.

Endosperm cellularization failure induces a dehydration-stress response leading to embryo arrest.

The endosperm is a nutritive tissue supporting embryo growth in flowering plants. Most commonly, the endosperm initially develops as a coenocyte (multinucleate cell) and then cellularizes. This process of cellularization is frequently disrupted in hybrid seeds generated by crosses between different flowering plant species or plants that differ in ploidy, resulting in embryo arrest and seed lethality. The reason for embryo arrest upon cellularization failure remains unclear. In this study, we show that triploid Arabidopsis thaliana embryos surrounded by uncellularized endosperm mount an osmotic stress response that is connected to increased levels of abscisic acid (ABA) and enhanced ABA responses. Impairing ABA biosynthesis and signaling aggravated triploid seed abortion, while increasing endogenous ABA levels as well as the exogenous application of ABA-induced endosperm cellularization and suppressed embryo growth arrest. Taking these results together, we propose that endosperm cellularization is required to establish dehydration tolerance in the developing embryo, ensuring its survival during seed maturation.

TDP-43 safeguards the embryo genome from L1 retrotransposition.

Transposable elements (TEs) are genomic parasites that propagate within the host genome and introduce mutations. Long interspersed nuclear element-1 (LINE-1 or L1) is the major TE class, which occupies nearly 20% of the mouse genome. L1 is highly active in mammalian preimplantation embryos, posing a major threat to genome integrity, but the mechanism of stage-specific protection against L1 retrotransposition is unknown. Here, we show that TAR DNA-binding protein 43 (TDP-43), mutations in which constitute a major risk factor for amyotrophic lateral sclerosis, inhibits L1 retrotransposition in mouse embryonic stem cells (mESCs) and preimplantation embryos. Knockdown of TDP-43 resulted in massive genomic L1 expansion and impaired cell growth in preimplantation embryos and ESCs. Functional analysis demonstrated that TDP-43 interacts with L1 open reading frame 1 protein (L1 ORF1p) to mediate genomic protection, and loss of this interaction led to derepression of L1 retrotransposition. Our results identify TDP-43 as a guardian of the embryonic genome.

Developmental exposure to sertraline impaired zebrafish behavioral and neurochemical profiles.

The number of people suffering from mental health problems is rising, with anxiety and depression now the most commonly diagnosed psychiatric conditions. Selective serotonin reuptake inhibitors (SSRIs) are one of the most prescribed pharmaceuticals to treat these conditions, which has led to their common detection in many aquatic ecosystems. As the monoaminergic system shows a high degree of structural conservation across diverse animal phyla, a reasonable assumption is that the environmental levels of SSRIs in surface water can lead to adverse effects on fish and other aquatic wildlife. For instance, Sertraline (SER), a widely prescribed SSRI, has been shown to induce adverse effects in fish, albeit most of the reports used exposure concentrations exceeding those occurring in natural environments. Therefore, there is still a great lack of knowledge regarding SERs effects in fish species, especially during early life stages. This study describes the evaluation of developmental exposure of zebrafish (Danio rerio) to environmentally relevant concentrations of SER (from 0.01 to 10μg/L), using a battery of key survival behaviors and further relating them with the expression of genes and neurochemical profiles of the monoaminergic system. We found that developmental exposure to SER did not affect embryo morphogenesis and growth. However, concentrations as low as 0.1μg/L induced hypolocomotion and delayed learning. The observed behavioral impairment was associated with augmented serotonin levels rather than other neurochemicals and molecular markers, highlighting the relationship between serotonin signaling and behavior in zebrafish.

Enhancing gosling growth and secretion of somatotrophic and thyrotrophic axis hormones through egg turning during incubation

ABSTRACT 1. Growth performance of Yangzhou geese hatched from eggs with turning angles of 50° or 70° was evaluated in association with serum hormones and somatotrophic gene mRNA expression. 2. Egg turning at 70° significantly (P< 0.05) increased hatchability, gosling quality and hatching weight. Gosling post-hatch body weight, leg and breast muscle weight in the 70° turning group was significantly heavier until 50 d of age. 3. Serum concentrations of GH were significantly higher until 30 d of age in the 70° turning group goslings, and those of IGF-I and T3 were higher from hatching to 50 d of age. 4. The mRNA expression of GHRH, pituitary GH, liver and leg muscle IGF-I were all significantly higher at 1 and 30 d of age after hatch, but not at 70 d after hatch, in the 70° turning group. 5. Egg turning at 70° during incubation improves embryo and gosling quality and growth performance through up-regulation of gene expression and secretion of somatotrophic axis hormones, GHRH, GH and IGF-I, as well as T3.

LBMON172 Impact Of Photoperiodic Green Light During Incubation On Change Hormone In The Embryo Of Chicken

Abstract Background The poultry industry discovered that an increase in light intensity can accelerate embryonic development. In nature, chicken embryos of different ages and species certainly receive some light during incubation, while, in industrial hatcheries, eggs are incubated in darkness for 21 days, so exposing fertile eggs to light can increase the embryo's growth and decrease the incubation period. Objectives The aim of this study was to assess the effect of exposure of fertile Ross 308 eggs to a photoperiod of green on accelerates embryo development and alters hatch-related hormones (growth hormone, thyroid, and corticosterone). Methods This study was carried out to evaluate the impact of the photoperiod of green light from day 1 to day 18 of incubation time, on embryo growth, and hormone concentration (growth hormone, thyroid, and corticosterone). In the Three groups, no light-dark cycle was used in the first group (LD), the second group was used 12-h light, 12-h dark (LDL), and the third group was used 24-h light (LL), the third group. The light was provided by light wavelength green LED light (522 nm) mounted in a frame that was placed above the top tray of eggs to give an even spread of illumination. Eggs (n=300/group) with four replicates (n=25/replicate) from fertile Ross 308 broiler breeders were used in this experiment. Hormones were measured using a kit supplied by the (Sunlong Biotech Co., Ltd) company for all hormones using an ELISA device, samples were taken at the age of 7, 14, and 18 days of hatching using blood drawn from the eggshell using a 1 ml syringe with a 23-gauge needle. Results The results showed a significant improvement (P&amp;lt;0. 01) in the concentration of growth hormone, thyroid, and corticosterone) to the second group was used 12-h light, 12-h dark (LDL), compared to the other of groups. Conclusions The results of this study indicate that green light accelerates embryo development and alters hatch-related hormones (growth hormone, thyroid, and corticosterone). Presentation: Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.

Bisphenol AF induces multiple behavioral and biochemical changes in zebrafish (Danio rerio) at different life stages

As common environmental endocrine-disrupting chemicals (EDCs), bisphenol AF (BPAF) raises potential concerns for aquatic organisms due to its widespread presence and continued release in the aquatic environment. This research aimed to use zebrafish embryos and adult fish to explore the effects of environmentally relevant concentrations (5 μg/L), 50 μg/L and 500 μg/L of BPAF on zebrafish embryonic development, behavioral alterations, and the potential mechanisms driving these effects. The results showed that 500 μg/L of BPAF severely affected the growth and development of embryos. In behavioral experiments, all concentrations of BPAF significantly inhibited the locomotor activity of larvae, 50 and 500 μg/L BPAF significantly altered the anxiety-like and aggressive behavior of adult zebrafish. Furthermore, environmentally relevant concentrations and higher concentrations of BPAF induced varying degrees of oxidative stress in both embryonic and adult fish. The most significant histopathological changes and decreased acetylcholinesterase (AChE) activity were observed in the brain at 50 and 500 μg/L of BPAF. We hypothesized that oxidative stress is an important cause of behavioral disturbances in larvae and adult fish. To our best knowledge, the present experiment is a pioneer in studying the effects of BPAF on a variety of complex behaviors (swimming performance, anxiety-like, social behavior, aggression) in zebrafish, which emphasizes the potential health risk of higher concentrations of BPAF in terms of induced neurotoxicity.

Umbilical Cord Mesenchymal Stem Cells Seeded on Small Intestinal Submucosa to Repair the Uterine Wall Injuries.

Objective: The effectiveness of tissue engineering materials combining porcine small intestine submucosa (SIS) and umbilical cord mesenchymal stem cells (UC-MSCs) on uterine injury in female rat after full-thickness uterine resection was evaluated as a basis for clinical treatment of postoperative uterine injury. Methods: After complex culture with SIS and UC-MSCs, cell adhesion, growth, and proliferation were assessed. Before the implantation, a surgical procedure of bilateral full-thickness uterine resection (0.5-2.0 cm long and 0.3 cm wide) was performed to obtain the rat uterine injury model, while the sham-operated rats were used as controls. Hematoxylin-eosin (H&E) staining results and fertility of female rats in each group were assessed to determine the critical resection length of the full-thickness uterine resection. Then SIS or UC-MSCs-SIS were implanted into the female rats from the uterine injury group, followed by assessments of H&E staining, the expression of ki67, α-SMA, and leukemia inhibitory factor (LIF), and fertility to determine the effectiveness of SIS and UC-MSCs-SIS on uterine injury in female rat. Results: At 24, 48, and 72 h, the cells grew progressively on the SIS material. In the 1.5 cm and 2.0 cm groups, the pregnancy rate, proportion of the uterus supporting live embryo growth, number of live embryos, and proportion of live embryos were all significantly less than those in the 0.5 cm and sham-operated groups. In the 2.0 cm group, there was little tissue regeneration at the center of the injury and not conducive to subsequent assessment. The UC-MSCs-SIS and SIS groups were better on morphological development, cell proliferation, LIF expression, and fertility than the control group. Conclusions: UC-MSCs show good adhesion, growth, and proliferation on the SIS scaffold material. The optimal resection length in full-thickness uterine resection on female rat is 1.5 cm. UC-MSCs-SIS is the effective treatment for repairing a injury after the full-thickness resection of the uterus in this research. Impact Statement The acquired severe uterus injury is a serious condition, which prone to uterine adhesions. Postoperative endometrial repairment and prevention of intrauterine adhesion recurrence are two major clinical challenges. Fortunately, the development of tissue engineering technology makes repairing a uterine injury possible. There are two main contributions from this study. First, due to ethical requirements, it is difficult to assess the repairing effect on uterus by invasive experiments in a clinical practice. Therefore, we constructed a full-thickness uterine injury rat model, which allows us to assess the repairing effect of treatments after severe uterine injuries in vivo. Second, it explored the effect of using a combination of and umbilical cord mesenchymal stem cells and small intestine submucosa materials on improving uterine repairments, providing a potential possibility for a future clinical practice.

Exogenous gibberellin can effectively and rapidly break intermediate physiological dormancy of Amsonia elliptica seeds.

Accelerated global warming is leading to the loss of plant species diversity, and ex situ preservation of seeds is becoming an increasingly important aspect of species conservation. However, information on dormancy and germination is lacking in many endangered species. Amsonia elliptica (Apocynaceae) is the only Amsonia species native to Korea, and the South Korean Ministry of Environment has designated it Class II endangered wildlife. Nevertheless, the dormancy class and the dormancy breaking method for seeds of this species for germination are not precisely known. We identified the structure of A. elliptica seeds and the causes of dormancy, which inhibits germination. In addition, we tried to develop an effective germination promotion method by testing the wet stratified condition, which breaks dormancy, and the form of gibberellin that can replace it. Fresh seeds of A. elliptica imbibe water, but the covering layers (endosperm and seed coat) inhibit germination by mechanically restricting the embryo. Initial germination tests confirmed low embryo growth potential and physiological dormancy (PD). Restriction due to the covering layer was eliminated by seed scarification, and abnormal germination was observed. After 12 weeks of cold moist stratification at 4°C, only 12% of seeds germinated. However, 68.8% of seeds subjected to 8 weeks of warm moist stratification followed by 12 weeks of cold stratification germinated, indicating that warm stratification pretreatment before cold stratification is effective in breaking dormancy. A. elliptica seeds exhibited intermediate PD. Furthermore, 61.3% of seeds soaked in 500 mg/L GA4+7 for 14 days and incubated at 25/15°C germinated. Therefore, GA4+7 rapidly broke the dormancy of A. elliptica seeds compared with warm plus cold stratification treatment, thus providing an efficient method for seedling production.

Dynamic regulation of the transcriptome and proteome of the equine embryo during maternal recognition of pregnancy.

During initial maternal recognition of pregnancy (MRP), the equine embryo displays a series of unique events characterized by rapid blastocyst expansion, secretion of a diverse array of molecules, and transuterine migration to interact with the uterine surface. Up to date, the intricate transcriptome and proteome changes of the embryo underlying these events have not been critically studied in horses. Thus, the objective of this study was to perform an integrative transcriptomic (including mRNA, miRNAs, and other small non-coding RNAs) and proteomic analysis of embryos collected from days 10 to 13 of gestation. The results revealed dynamic transcriptome profiles with a total of 1311 differentially expressed genes, including 18 microRNAs (miRNAs). Two main profiles for mRNAs and miRNAs were identified, one with higher expression in embryos ≤5 mm and the second with higher expression in embryos ≥7 mm. At the protein level, similar results were obtained, with 259 differentially abundant proteins between small and large embryos. Overall, the findings demonstrated fine-tuned transcriptomic and proteomic regulations in the developing embryo associated with embryo growth. The identification of specific regulation of mRNAs, proteins, and miRNAs on days 12 and 13 of gestation suggested these molecules as pivotal for embryo development and as involved in MRP, and in establishment of pregnancy in general. In addition, the results revealed new insights into prostaglandin synthesis by the equine embryo, miRNAs and genes potentially involved in modulation of the maternal immune response, regulation of endometrial receptivity and of late implantation in the mare.

Mother-Fetus Immune Cross-Talk Coordinates "Extrinsic"/"Intrinsic" Embryo Gene Expression Noise and Growth Stability.

Developmental instability (DI) is thought to be inversely related to a capacity of an organism to buffer its development against random genetic and environmental perturbations. DI is represented by a trait’s inter- and intra-individual variabilities. The inter-individual variability (inversely referred to as canalization) indicates the capability of organisms to reproduce a trait from individual to individual. The intra-individual variability reflects an organism’s capability to stabilize a trait internally under the same conditions, and, for symmetric traits, it is expressed as fluctuating asymmetry (FA). When representing a trait as a random variable conditioned on environmental fluctuations, it is clear that, in statistical terms, the DI partitions into “extrinsic” (canalization) and “intrinsic” (FA) components of a trait’s variance/noise. We established a simple statistical framework to dissect both parts of a symmetric trait variance/noise using a PCA (principal component analysis) projection of the left/right measurements on eigenvectors followed by GAMLSS (generalized additive models for location scale and shape) modeling of eigenvalues. The first eigenvalue represents “extrinsic” and the second—“intrinsic” DI components. We applied this framework to investigate the impact of mother–fetus major histocompatibility complex (MHC)-mediated immune cross-talk on gene expression noise and developmental stability. We showed that “intrinsic” gene noise for the entire transcriptional landscape could be estimated from a small subset of randomly selected genes. Using a diagnostic set of genes, we found that allogeneic MHC combinations tended to decrease “extrinsic” and “intrinsic” gene noise in C57BL/6J embryos developing in the surrogate NOD-SCID and BALB/c mothers. The “intrinsic” gene noise was negatively correlated with growth (embryonic mass) and the levels of placental growth factor (PLGF), but not vascular endothelial growth factor (VEGF). However, it was positively associated with phenotypic growth instability and noise in PLGF. In mammals, the mother–fetus MHC interaction plays a significant role in development, contributing to the fitness of the offspring. Our results demonstrate that a positive impact of distant MHC combinations on embryonic growth could be mediated by the reduction of “intrinsic” gene noise followed by the developmental stabilization of growth.

Endosperm ontogeny through the lens of epigenetics

Endosperm tissue is crucial to seed development. Monocots and dicots have evolved different fates for their endosperm: it is usually consumed in dicots during seed development, while monocots seeds retain the endosperm till maturity. Recently, Wu et al. addressed the role of divergent epigenetic regulation over functionally conserved IKU2 gene contributing to silenced or persistent endosperm proliferation and has provided insights into diverged seed ontogeny pattern in plants. Here, we highlight the novel findings of this study and their potential significance. Seed production represents a remarkable life-history adaptation that has been established during plant evolution. In flowering plants, a double fertilization event initiates seed development, producing embryo and the endosperm. Endosperm (3n) is a triploid outcome of second fertilization, which occurs when a female central cell (2n) fuses with one of the two male gametes (n) carried by the pollen tube (Ingram, 2020). It develops precociously and is primed to perform nutritional and developmental functions for embryo growth (Povilus & Gehring, 2022). Different taxa have evolved specific seed formation patterns that elicit different levels of endosperm perseverance during development (Baroux et al., 2002). As a result of this, the endosperm-to-embryo ratio in mature seeds has varied gradually among different plants. As an example, endosperm in cereals is formed and retained as a nutritive reserve till seed maturity. In several eudicots such as Arabidopsis, early formed endosperm is substantially devoured to serve during embryo maturation. In peas with non-persistent endosperm, the tissue appears to be absorbed in the early free nuclear division phase before cell wall formation. The Podostomenaceae and Orchidaceae are the two endosperm-free lineages because their seeds lack or terminate endosperm nuclear divisions during early stages. Endosperm develops through two major phases: first syncytial involving continuous nuclear divisions, and the subsequent cellularization in which the free nuclear state develops cell wall (Baroux et al., 2002). Despite that the embryo produces the next generation progeny, endosperm proliferation and cellularization timing is crucial to embryo viability.