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Introduction: The pivotal role of extracellular vesicles (EVs) in facilitating effective communication between the embryo and maternal cells during the preimplantation stage of pregnancy has been extensively explored. Nonetheless, inquiries persist regarding the alterations in EV cargo from endometrial cells under stress conditions and its potential to elicit specific stress responses in trophoblast cells. Thus, the aim of this study was to elucidate the involvement of EV miRNA miRNAs in transmitting stress signals from maternal cells to trophoblasts. Methods: The receptive endometrial epithelium analogue RL95-2 cells were subjected to stress induction with 200 µM CoCl2 for 24 h before EV isolation. JAr trophoblast spheroids, which serve as embryos, were subjected to treatment with stressed or unstressed EVs derived from RL95-2 cells for 24 h. Transcriptomic alterations in the treated JAr spheroids as well as in the untreated group, as a negative control, were investigated by mRNA sequencing. Furthermore, the changes in EV miRNAs were assessed by sequencing EV samples. Results: A comprehensive analysis comparing the miRNA profiles between stressed and unstressed EVs revealed significant changes in 25 miRNAs. Furthermore, transcriptomic analysis of JAr spheroids treated with stressed RL95-2EVs versus unstressed EVs or the untreated group demonstrated 6 and 27 differentially expressed genes, respectively. Pathway enrichment analysis showed that stressed EVs induce alterations in gene expression in trophoblast cells, which is partially mediated by EV microRNAs. Discussion: Our results suggest that EVs can transfer stress signals from endometrial cells to the embryo. These discoveries shed new light on the mechanism underlying implantation failures under stress conditions. Unraveling the role of EVs in transmitting stress signals, can extend our knowledge to pave the way for targeted interventions to manage stressrelated implantation failures. [ABSTRACT FROM AUTHOR]

Mammalian embryo development is initiated by the union of paternal and maternal gametes. Upon fertilization, their epigenome landscape is transformed through a series of finely orchestrated mechanisms that are crucial for survival and successful embryogenesis. Specifically, maternal or oocyte-specific reprogramming factors modulate germ cell specific epigenetic marks into their embryonic states. Rapid and dynamic changes in epigenetic marks such as DNA methylation and histone modifications are observed during early embryo development. These changes govern the structure of embryonic genome prior to zygotic genome activation. Differential changes in epigenetic marks are observed between paternal and maternal genomes because the structure of the parental genomes allows interaction with specific oocyte reprogramming factors. For instance, the paternal genome is targeted by the TET family of enzymes which oxidize the 5-methylcytosine (5mC) epigenetic mark into 5-hydroxymethylcytosine (5hmC) to lower the level of DNA methylation. The maternal genome is mainly protected from TET3-mediated oxidation by the maternal factor, STELLA. The TET3- mediated DNA demethylation occurs at the global level and is clearly observed in many mammalian species. Other epigenetic modulating enzymes, such as DNA methyltransferases, provide fine tuning of the DNA methylation level by initiating de novo methylation. The mechanisms which initiate the epigenetic reprogramming of gametes are critical for proper activation of embryonic genome and subsequent establishment of pluripotency and normal development. Clinical cases or diseases linked to mutations in reprogramming modulators exist, emphasizing the need to understand mechanistic actions of these modulators. In addition, embryos generated via in vitro embryo production system often present epigenetic abnormalities. Understanding mechanistic actions of the epigenetic modulators will potentially improve the well-being of individuals suffering from these epigenetic disorders and correct epigenetic abnormalities in embryos produced in vitro. This review will summarize the current understanding of epigenetic reprogramming by TET enzymes during early embryogenesis and highlight its clinical relevance and potential implication for assisted reproductive technologies. [ABSTRACT FROM AUTHOR]

Ultrasonography is widely used to monitor pregnancy in viviparous species, but it is underutilized as a tool to characterize embryonic development in oviparous species. Currently, a multi-institutional effort is underway to rewild the endangered zebra shark (Stegostoma tigrinum) to locations where this species was previously extirpated by leveraging the reproductive efforts of aquarium sharks as a source of brood stock. Zebra sharks are oviparous and fecund, but a large percentage of their yolked eggs do not result in hatchlings. Therefore, ultrasonography represents a potential tool for distinguishing fertile eggs with developing embryos from degrading eggs, and to diagnose changes in early embryonic development predictive of poor outcomes. The objectives of the current study were to use ultrasonography to assess egg fertility, monitor early embryonic development, and identify morphological indicators that may be predictive of early embryonic mortality. Freshly laid eggs from four female zebra sharks were collected and inventoried daily at Aquarium of the Pacific. Eggs were incubated undisturbed for 2 to 4 weeks and subsequently examined weekly via ultrasound to assess fertility and monitor embryo development. Among 120 fertile eggs, embryos were identified as early as 8 days post-oviposition, with average (±SD) time to first observation at 30 ± 7 days. Morphological and behavioral abnormalities were observed for most embryos (n = 84, 70%) as early as 16 days and up to 95 days post-oviposition. Common abnormalities included: bent or curled tails, vesicle(s) at the base of the yolk stalk, and slow or weak movement. Only one embryo survived to hatch during the study and was genetically-confirmed parthenogenetic, suggesting hatching success for parthenotes is low (<1%). Ultrasonography was demonstrated to be an effective and non-invasive method to determine egg fertility, identify embryos with developmental abnormalities, and monitor embryo growth. [ABSTRACT FROM AUTHOR]

Background: Appropriate regulation of genes expressed in oocytes and embryos is essential for acquisition of developmental competence in mammals. Here, we hypothesized that several genes expressed in oocytes and pre-implantation embryos remain unknown. Our goal was to reconstruct the transcriptome of oocytes (germinal vesicle and metaphase II) and pre-implantation cattle embryos (blastocysts) using short-read and long-read sequences to identify putative new genes. Results: We identified 274,342 transcript sequences and 3,033 of those loci do not match a gene present in official annotations and thus are potential new genes. Notably, 63.67% (1,931/3,033) of potential novel genes exhibited coding potential. Also noteworthy, 97.92% of the putative novel genes overlapped annotation with transposable elements. Comparative analysis of transcript abundance identified that 1,840 novel genes (recently added to the annotation) or potential new genes were differentially expressed between developmental stages (FDR < 0.01). We also determined that 522 novel or potential new genes (448 and 34, respectively) were upregulated at eight-cell embryos compared to oocytes (FDR < 0.01). In eight-cell embryos, 102 novel or putative new genes were co-expressed (|r|> 0.85, P < 1 × 10–8) with several genes annotated with gene ontology biological processes related to pluripotency maintenance and embryo development. CRISPR-Cas9 genome editing confirmed that the disruption of one of the novel genes highly expressed in eight-cell embryos reduced blastocyst development (ENSBTAG00000068261, P = 1.55 × 10–7). Conclusions: Our results revealed several putative new genes that need careful annotation. Many of the putative new genes have dynamic regulation during pre-implantation development and are important components of gene regulatory networks involved in pluripotency and blastocyst formation. [ABSTRACT FROM AUTHOR]

The present study reports the formation of claws in lizards and their cornification. From a flat epidermis with lose mesenchyme, the skin forms undulations that become symmetric domes and later asymmetric for the elongation of their proximal part that gives rise to the outer scale surface. At the tip of digits claws develop in association with a mesenchyme that surrounds the cartilage of the last phalange. Beta‐cells of claws appear 2–3 embryonic stages before those of scales formed in other body regions, including digital scales. The epidermis of the developing claw initially forms 3–4 embryonic layers under which elongated beta‐cells accumulate long bundles of corneous material, immunopositive for CBPs. Claw beta‐keratinocytes incorporate tritiated proline and accumulate numerous, oriented corneous bundles that rapidly occupy the entire cell. The bundles are electron‐dense under transmission electron microscopy, suggesting that, in association to CBPs, other proteins are synthesized and increase the mechanical resistance of claws. Immunolabelling for cysteine‐rich IFKs, HA and HB, shows that these keratins co‐localize with CBPs only in claws but are low to absent in digital scales and adhesive setae. This indicates that the hardness of claws mainly depends from the association between these different proteins rich in glycine and cysteine. [ABSTRACT FROM AUTHOR]

Increasing levels of global environmental change may have negative impacts on fertility and embryo viability in animals that could explain a recently reported increase in hatching failure in bird eggs across the globe. Here we test this relationship again by analyzing a dataset containing almost twice as many species and covering a longer time period than earlier works (n  = 431 species during the period 1906–2022). We also tested for effects of Red List status and global population size. We found that hatching failure rates in a combined group of bird species currently classified as threatened (IUCN Red List categories Critically Endangered, Endangered and Vulnerable) or Near Threatened, peaked in the late 1970s to early 1980s and thereafter declined. A similar trend also existed in species with relatively small global populations. In contrast, no temporal trends were found in species in the Least Concern category, or in species with large global populations. Moreover, hatching failure rates declined significantly with increasing global population sizes. The temporal peak of hatching failure rates in threatened and Near Threatened species corresponds with the peak in environmental levels of the insecticide DDT. While this could suggest that environmental pollution caused the temporal trends in hatching failure rates, effects of inbreeding in small and threatened populations sampled more frequently during this period could not be excluded. Although we found no evidence suggesting that the rates of hatching failure in bird eggs are increasing, the current study supports previous works showing that species of high conservation concern appear to be more susceptible to factors leading to reproductive failure than other species. [ABSTRACT FROM AUTHOR]

Diapause is a coping strategy characteristic to many invertebrates and vertebrates including more than 100 mammalian species. Preserving the genetic diversity of rare and endangered diapausing species is important for maintaining ecological systems. The purpose of this work was to compare the surgical model of diapause and the pharmacological model based on injecting DL-α-difluoromethylornithine (DL-α-DFMO) into mice. Another goal was to investigate the intriguing possibility of controlling the state of diapause in vitro by exposing murine embryos to putrescine and/or DL-α-DFMO. Although the pharmacological model a priori seems to be attractive for applying it to other mammalian species besides mice, since it does not require surgical intervention, our results on mice demonstrated that this model is less effective compared to the traditional surgical model of diapause. Our data indicates that the effects of DL-α-DFMO on mouse embryos are mediated via its effect on the uterus, as it was not possible to maintain dormancy state in diapausing embryos in vitro by this agent. Meanwhile, in vitro exposure to putrescine facilitates the re-activation of diapausing embryos, as evidenced by the higher rate of blastocysts adhesion and the more advanced stages of ICM outgrowth compared to controls. Our results on mice presented hereby indicate that the surgical model is more reliable than DL-α-DFMO diapause model. Moreover, our results proved that putrescine is a potent tool to re-activate murine diapausing embryos in vitro; this may be considered an ecologically important issue relevant to the conservation problem. [ABSTRACT FROM AUTHOR]

Survival of the immobile embryo in response to rising temperature is important to determine a species' vulnerability to climate change. However, the collective effects of 2 key thermal characteristics associated with climate change (i.e., rising average temperature and acute heat events) on embryonic survival remain largely unexplored. We used empirical measurements and niche modeling to investigate how chronic and acute heat stress independently and collectively influence the embryonic survival of lizards across latitudes. We collected and bred lizards from 5 latitudes and incubated their eggs across a range of temperatures to quantify population‐specific responses to chronic and acute heat stress. Using an embryonic development model parameterized with measured embryonic heat tolerances, we further identified a collective impact of embryonic chronic and acute heat tolerances on embryonic survival. We also incorporated embryonic chronic and acute heat tolerance in hybrid species distribution models to determine species' range shifts under climate change. Embryos' tolerance of chronic heat (T‐chronic) remained consistent across latitudes, whereas their tolerance of acute heat (T‐acute) was higher at high latitudes than at low latitudes. Tolerance of acute heat exerted a more pronounced influence than tolerance of chronic heat. In species distribution models, climate change led to the most significant habitat loss for each population and species in its low‐latitude distribution. Consequently, habitat for populations across all latitudes will shift toward high latitudes. Our study also highlights the importance of considering embryonic survival under chronic and acute heat stresses to predict species' vulnerability to climate change. [ABSTRACT FROM AUTHOR]

Catholic thinkers generally agree that artificial womb technology (AWT) would be permissible in cases of partial ectogenesis to assist severely premature infants, but there is substantially more debate concerning whether AWT could be used to save frozen embryos, which are the result of in vitro fertilization (IVF). In many cases, these embryos have been abandoned and left in a permanently cryogenic state, which is an affront to their human dignity. While AWT would allow people to adopt these embryos and give them an opportunity to develop, it gives rise to serious concerns over the possibility of scandal and the potential for cooperation in evil. Therefore, the author argues that even though AWT may one day represent a solution to this tragedy, it is currently not a morally licit answer, given the widespread use and approval of IVF in our culture. [ABSTRACT FROM AUTHOR]

Christian pro-lifers often respond to Thomson's defense of abortion that the violinist is allowed to die while the embryo is killed. Boonin and McMahan counter that this distinction does not provide an objection to extraction abortions that disconnect embryos and allow them to die. I disagree. I first argue that letting die and killing are not to be distinguished by differences between acts and omissions, moral and immoral motives, intentional or unintentional deaths, and causing or not causing a pathology. I offer a taxonomy in which hysterotomies turn out to be killings. I then argue that if either the placenta is considered an organ of the embryo or the embryo is construed as a part of the pregnant woman, then abortion pills kill rather than allow death. So, assuming that killing people is morally worse than letting them die, extraction abortions can be condemned to the same degree as other abortions. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. Massive genotyping in cattle has uncovered several deleterious haplotypes that cause preterm mortality. Holstein haplotype 5 (HH5) is a deleterious haplotype present in the Holstein Friesian population that involves the ablation of the transcription factor B1 mitochondrial (TFB1M) gene. The developmental stage at which HH5 double-carrier (DC, homozygous) embryos or fetuses die remains unknown and this is a relevant information to estimate the economic losses associated with the inadvertent cross between carriers. To determine whether HH5 DC survive to maternal recognition of pregnancy, embryonic day (E) 14 embryos were flushed from superovulated carrier cows inseminated with a carrier bull. Double-carrier E14 conceptuses were recovered at Mendelian rates but they failed to achieve early elongation, as evidenced by a drastic reduction of their extra-embryonic membranes, which were >26-fold shorter than those of carrier or noncarrier embryos. To assess development at earlier stages, TFB1M knockout (KO) embryos—functionally equivalent to DC embryos—were generated by clustered regularly interspaced short palindromic repeats (CRISPR) technology and cultured to the blastocyst stage, in vitro culture day (D) 8, and to the early embryonic disc stage, D12. No significant effect of TFB1M ablation was observed on the differentiation and proliferation of embryonic lineages and relative mitochondrial DNA (mtDNA) content up to D12. In conclusion, HH5 DC embryos are able to develop to early embryonic disc stage but fail to undergo early conceptus elongation, which is required for pregnancy recognition. [ABSTRACT FROM AUTHOR]

The aims of this study were to determine the effect of the embryo flushing technique and the number of flushing attempts performed by operators of different experience on embryo recovery (ER). Ten non-lactating mares were inseminated with the same stallion in six cycles each (n = 60). Embryo flushing (EF) was performed 7–9 days after ovulation by three operators (OP; 20 EF cycles each): OP1 had performed >500 EF before the study, while OP2 and 3 had performed 0 EF. Each EF was performed with 2 flushing attempts (FA) using 1L of ringer's lactate "in-and-out" using two EF techniques: 1) uterine massage (UM): continuous ballottement and massage of the uterus per rectum during ringer lactate recovery, 2) gravity flow (GF): the ringer lactate was allowed to flow back without massaging the uterus. In both groups, 20 IU of oxytocin were administered at the second FA and the ringer lactate was allowed to remain in the uterus for 3 min before recovery. An extra FA was performed in each group using 0.5 L of ringer lactate and uterine massage. More embryos (P < 0.05) per ovulation were recovered in the UM (17/33, 0.51) than in the GF group (8/36, 0.22). For the UM group, 16/17 embryos (94.1 %) were recovered in the first FA, while only one embryo in the second FA (1/17, 5.9 %). In the GF group, 4 embryos were recovered in each FA. No embryo was found in the extra FA in the UM group, while seven additional embryos were found in the GF group (5/7 flushed by OP1; P < 0.05). The overall ER per cycle was 70, 40, and 45 % for OP1, 2 and 3, respectively. In conclusion, highest embryo recovery is achieved in EF performed with UM, with the majority of embryos being flushed in the first FA. • Uterine massage is more effective than gravity flow to flush out embryos. • The majority of embryos are recovered in the 1st flushing attempt by uterine massage. • The degree of expansion of the uterine horns with flushing media influences embryo recovery. [ABSTRACT FROM AUTHOR]

To assess whether the change in embryo morphology from precryopreservation to postthaw is associated with the embryo transfer success rates in single euploid embryo transfer cycles. Retrospective cohort study. Academic affiliated fertility clinic. Patients who underwent a single euploid embryo transfer cycle from September 2016 to April 2022 were included. A decision support tool was used to assign each embryo a reproductive potential score on the basis of the day of biopsy, expansion, and grade of trophectoderm and inner cell mass at the time of cryopreservation and after thaw. Embryos were divided into 4 groups: group 1 included embryos with the same score after thaw (reference); group 2 included those with a higher score; group 3 included those with a lower score; and group 4 included those that did not re-expand after thaw. No interventions administered. The primary outcome was the live birth rates (LBRs) per embryo transfer. The secondary outcomes included the chemical pregnancy, clinical pregnancy, and clinical pregnancy loss rates. Comparative statistics and univariate analyses were performed using the Kruskal-Wallis and χ2tests. Multivariate logistic regression fitted with generalized estimating equation was performed to compare the odds of live birth between groups. A total of 7,750 embryo transfers performed for 4,613 patients met inclusion criteria: 5,331 in group 1; 486 in group 2; 1,726 in group 3; and 207 in group 4. In the univariate analysis, there was a statistically significant difference in the LBR between groups 1, 2, 3, and 4 (55.8% vs. 51.4%, 47.5%, and 26.6%). Logistic regression controlling for oocyte age, antimüllerian hormone, body mass index, endometrial thickness, year of embryo transfer, time from thaw to final grading, and embryo score before cryopreservation showed significantly lower odds of live birth when the embryo was downgraded (odds ratio [OR], 0.70; confidence interval [CI], 0.62–0.79) or did not re-expand (OR, 0.36; CI, 0.26–0.51) than those with no change in score. When controlling for all variables, there was a significant increase in the odds of live birth between embryos that had a higher score after thaw and those without a change (OR, 1.42; CI, 1.14–1.76). There was no significant difference in the clinical pregnancy loss rate among the 4 groups. The change in the quality of the embryo after thaw is an important factor in embryo transfer success. In an adjusted analysis, the chemical and clinical pregnancy rates and LBR per embryo transfer all significantly decrease in embryos that were downgraded or did not expand on the day of single euploid embryo transfer. Embryos that re-expand and have improved quality after thaw have the highest odds of live birth. [ABSTRACT FROM AUTHOR]

To study the development and clinical validation of the ART Pipetting Robot for the IVF Laboratory (APRIL), a liquid-handling robot customized for the precise preparation of microdroplet culture dishes in the field of in vitro fertilization (IVF). A prospective randomized study conducted at an academic IVF center comparing mouse and human embryo outcomes and quantitative measures of accuracy in embryo dishes prepared using APRIL compared with standard manual preparation. Academic IVF center. The study involved the assessment of the automated culture dish preparation system, APRIL, compared with manual preparation methods in the context of IVF treatment. ART Pipetting Robot for the IVF Laboratory is an enclosed liquid-handling robot equipped with custom three-dimensional–printed adapters and designed to dispense embryo culture media and mineral oil into microdroplet culture dishes. The study evaluated the precision and consistency of APRIL in culture dish preparation by looking at droplet mass, pH of prepared media droplets, and mouse and human embryo development rates. Clinical implementation was assessed by comparing embryo development and outcomes in dishes prepared by APRIL and human embryologists. Compared with embryo culture dishes prepared using standard manual procedures, embryo culture dishes prepared using APRIL demonstrated a greater than 10-fold improvement in consistency (coefficient of variation, 0.46% vs. 6%–7%), maintained optimal pH levels (pH range, 7.281–7.33 vs. 7.275–7.311), and had a greater mouse embryo blastocyst rate (100% vs. 90%–91%). Human embryos cultured in dishes prepared by APRIL had a higher rate of development on days 3 (92.4% vs. 82.6%) and 5 (19.75% vs. 15.57%), and a total number of usable embryos (50.3% vs. 46.1%) compared with manually prepared dishes, although the last two outcomes did not reach statistical significance. The results suggest that the use of an automated robotic system for preparation of embryo culture dishes may improve accuracy and outcome measures while reducing the need for trained laboratory personnel to prepare the dishes manually. [ABSTRACT FROM AUTHOR]

A commentary on the 2024 article "Reasons and Reproduction: Gene Editing and Genetic Selection," by Jeff McMahan and Julian Savulescu is presented. Topics covered include the assumption that genetic editing results in the same person being born as would have happened without editing, the problematic issue that is raised by the authors' use of impersonal considerations to justify their conclusions and the need to be careful about basing policy that infringes reproductive autonomy.

A commentary on the 2024 article "Reasons and Reproduction: Gene Editing and Genetic Selection," by J. McMahan and J. Savulescu is presented. Topics covered include the variations of the two-tier view of the authors, how the variations yield different ethical implications when causing a particular disability and a response to the objection that such a subject-dependent value profile would not work at the embryonic stage.

Many writers in bioethics, science, and medicine contend that embryo selection is a morally better way of avoiding genetic disorders then gene editing, as the latter has risks that the former does not. We argue that one reason to use gene editing is that in many cases it would be better for the person who would develop from the edited embryo, so that not to have done it would have been worse for that person. By contrast, embryo selection is never better for the person who develops from the selected embryo. This reason to use gene editing has, however, been challenged on two grounds: first, that it makes no difference, morally, whether a bad effect is worse for someone, or a good effect better for someone; and, second, that beneficent gene editing would not be unequivocally better for the person who would develop from the edited embryo. We argue that both of these objections can be satisfactorily answered and thus that there is indeed a significant moral reason, at least in some cases, to use gene editing rather than embryo selection. [ABSTRACT FROM AUTHOR]

Tetramethyl thiram disulfide (thiram) is a dimethyldithiocarbamate (DTC) pesticide and is widely used in China, but its high residue has caused widespread concern. In this study, we used zebrafish (Danio rerio) embryos as animal models to explore the relationship between notochord curvature and thyroxine caused by thiram in zebrafish embryos. Zebrafish embryos at 3 hours postfertilization (3 hpf) were exposed to low concentrations of thiram (0, 0.0024, 0.024, and 0.24 mg/L) for short-term (10, 30 min) or continuous exposure (1-4 d), and the relevant indicators were observed at 24, 48, 72, and 96 hpf. HPLC analysis results showed that the detectable concentration of thiram in zebrafish was 0.13 mg/kg (exposure from 3 hpf to 72 hpf). Morphological results showed that even short-term (30 min) thiram exposure increased mortality, delayed hatching, and caused notochord curvature in zebrafish embryos. Thiram exposure resulted in a decrease in gene expression of the thyroxine-related gene thyroid peroxidase (TPO). The detection of hormone levels indicated that thiram caused a decrease in the levels of tetraiodothyronine (T4) and triiodothyronine (T3). The results of this study indicate that one-time, short-term exposure to thiram still causes toxic effects on zebrafish embryos, and this effect may be related to thyroid hormones. This study also provides ideas for biological monitoring of dithiocarbamate pesticides. [ABSTRACT FROM AUTHOR]

A subgroup of endocrine‐disrupting chemicals have the ability to disrupt metabolism. These metabolism‐disrupting chemicals (MDCs) can end up in aquatic environments and lead to adverse outcomes in fish. Although molecular and physiological effects of MDCs have been studied in adult fish, few studies have investigated the consequences of metabolic disruption in fish during the earliest life stages. To investigate the processes affected by metabolic disruption, zebrafish embryos were exposed to peroxisome proliferator–activated receptor gamma (PPARγ) agonist rosiglitazone, the PPARγ antagonist T0070907, and the well‐known environmentally relevant MDC bisphenol A. Decreased apolipoprotein Ea transcript levels indicated disrupted lipid transport, which was likely related to the observed dose‐dependent increases in yolk size across all compounds. Increased yolk size and decreased swimming activity indicate decreased energy usage, which could lead to adverse outcomes because the availability of energy reserves is essential for embryo survival and growth. Exposure to T0070907 resulted in a darkened yolk. This was likely related to reduced transcript levels of genes involved in lipid transport and fatty acid oxidation, a combination of responses that was specific to exposure to this compound, possibly leading to lipid accumulation and cell death in the yolk. Paraoxonase 1 (Pon1) transcript levels were increased by rosiglitazone and T0070907, but this was not reflected in PON1 enzyme activities. The present study shows how exposure to MDCs can influence biochemical and molecular processes involved in early lipid metabolism and may lead to adverse outcomes in the earliest life stages of fish. Environ Toxicol Chem 2024;43:1880–1893. © 2024 The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effect of chemical gasification and HEPES as alternative systems to pH control during in vitro maturation on bovine oocytes competence. Groups of 20 bovine cumulus oocytes complexes (COCs) were randomly distributed and cultured for 24 h in one of the following experimental groups: (i) chemical reaction (ChRG) system: CO2 generated from sodium bicarbonate and citric acid reaction (ii) culture media TCM‐HEPES (HEPES‐G); and (iii) control group (CNTG) in conventional incubator. After in vitro maturation (IVM), the COCs were in vitro fertilized (IVF), and in vitro cultivated (IVC) in a conventional incubator. We evaluated oocyte nuclear maturation, cleavage and blastocyst rates, in addition to the relative mRNA expression of BAX, BMP‐15, AREG and EREG genes in oocytes and cumulus cells. The proportion of oocytes in metaphase II was higher in CNTG and ChRG (77.57% and 77.06%) than in the HEPES‐G (65.32%; p =.0408 and.0492, respectively). The blastocyst production was similar between CNTG and ChRG (26.20% and 28.47%; p =.4232) and lower (p =.001) in the HEPES‐G (18.71%). The relative mRNA expression of BAX gene in cumulus cells was significantly higher (p =.0190) in the HEPES‐G compared to the CNTG. Additionally, the relative mRNA expression of BMP‐15 gene was lower (p =.03) in oocytes from HEPES‐G compared to the CNTG. In conclusion, inadequate atmosphere control has a detrimental effect on oocyte maturation. Yet, the use of chemical gasification can be an efficient alternative to bovine COCs cultivation. [ABSTRACT FROM AUTHOR]

Background: The two‐pore domain potassium (K2P) channels are a major type of potassium channels that maintain the cell membrane potential by conducting passive potassium leak currents independent of voltage change. They play prominent roles in multiple physiological processes, including neuromodulation, perception of pain, breathing and mood control, and response to volatile anesthetics. Mutations in K2P channels have been linked to many human diseases, such as neuronal and cardiovascular disorders and cancers. Significant progress has been made to understand their protein structures, physiological functions, and pharmacological modifiers. However, their expression and function during embryonic development remain largely unknown. Results: We employed the zebrafish model and identified 23 k2p genes using BLAST search and gene cloning. We first analyzed vertebrate K2P channel evolution by phylogenetic and syntenic analyses. Our data revealed that the six subtypes of the K2P genes have already evolved in invertebrates long before the emergence of vertebrates. Moreover, the vertebrate K2P gene number increased, most likely due to two whole‐genome duplications. Furthermore, we examined zebrafish k2p gene expression during early embryogenesis by in situ hybridization. Each subgroup's genes showed similar but distinct gene expression domains with some exceptions. Most of them were expressed in neural tissues consistent with their known function of neural excitability regulation. However, a few k2p genes were expressed temporarily in specific tissues or organs, suggesting that these K2P channels may be needed for embryonic development. Conclusions: Our phylogenetic and developmental analyses of K2P channels shed light on their evolutionary history and potential roles during embryogenesis related to their physiological functions and human channelopathies. Key Findings: K2P potassium channels have a deep evolutionary origin, and vertebrates gained more K2p channel genes through whole genome duplications.23 K2P channels were identified in zebrafish, some resulting from the teleost‐specific whole genome duplication.Zebrafish k2p channel genes are expressed in various tissues and organs. K2p genes from the same subtypes showed overlapped expression domains.Some K2P channels may be needed for embryonic development, indicated by their temporary expressions in specific tissues or organs. [ABSTRACT FROM AUTHOR]

Somatic cell nuclear transfer (SCNT) is a very important reproductive technology with many diverse applications, such as fast multiplication of elite animals, the production of transgenic animals and embryonic stem (ES) cells. However, low cloning efficiency, a low live birth rate and the abnormally high incidence of abnormalities in the offspring born are attributed to incomplete or aberrant nuclear reprogramming. In SCNT embryos, the aberrant expression pattern of the genes throughout embryonic development is responsible for the incomplete nuclear reprogramming. The present study was carried out to identify the differential gene expression (DEGs) profile and molecular pathways of the SCNT and IVF embryos at different developmental stages (2 cell, 8 cell and blastocyst stages). In the present study, 1164 (2 cell), 1004 (8 cell) and 530 (blastocyst stage) DEGs were identified in the SCNT embryos as compared to IVF embryos. In addition, several genes such as ZEB1, GDF1, HSF5, PDE3B, VIM, TNNC, HSD3B1, TAGLN, ITGA4 and AGMAT were affecting the development of SCNT embryos as compared to IVF embryos. Further, Gene Ontology (GO) and molecular pathways analysis suggested, SCNT embryos exhibit variations compared to their IVF counterparts and affected the development of embryos throughout the different developmental stages. Apart from this, q-PCR analysis of the GDF1, TMEM114, and IGSF22 genes were utilized to validate the RNA-seq data. These findings contribute valuable insights about the different genes and molecular pathways underlying SCNT embryo development and offer crucial information for improving SCNT efficiency. [ABSTRACT FROM AUTHOR]

Rapid evaluation of the toxicity of metals using fish embryo acute toxicity is facilitative to ecological risk assessment of aquatic organisms. However, this approach has seldom been utilized for the comparative study on the effects of different metals to fish. In this study, acute and sub-chronic tests were used to compare the toxicity of Se(IV) and Cd in the embryos and larvae of Japanese medaka (Oryzias latipes). The embryos with different levels of dechorionation and/or pre-exposure were also exposed to Se(IV) and Cd at various concentrations. The results showed that the LC50-144 h of Cd was 1.3–5.2 folds higher than that of Se(IV) for the embryos. In contrast, LC50-96 h of Se(IV) were 200–400 folds higher than that of Cd for the larvae. Meanwhile, dechorionated embryos were more sensitive to both Se and Cd than the intact embryos. At elevated concentrations, both Se and Cd caused mortality and deformity in the embryos and larvae. In addition, pre-exposure to Cd at the embryonic stages enhanced the resistance to Cd in the larvae. However, pre-exposure to Se(IV) at the embryonic stages did not affect the toxicity of Se(IV) to the larvae. This study has distinguished the nuance differences in effects between Se(IV) and Cd after acute and sub-chronic exposures with/without chorion. The approach might have a potential in the comparative toxicology of metals (or other pollutants) and in the assessment of their risks to aquatic ecosystems. [ABSTRACT FROM AUTHOR]

Isobavachalcone (IBC) is a flavonoid component of the traditional Chinese medicine Psoraleae Fructus, with a range of pharmacological properties. However, IBC causes some hepatotoxicity, and the mechanism of toxicity is unclear. The purpose of this paper was to investigate the possible mechanism of toxicity of IBC on HepG2 cells and zebrafish embryos. The results showed that exposure to IBC increased zebrafish embryo mortality and decreased hatchability. Meanwhile, IBC induced liver injury and increased expression of ALT and AST activity. Further studies showed that IBC caused the increase of ROS and MDA the decrease of CAT, GSH, and GSH‐Px; the increase of Fe2+ content; and the changes of ferroptosis related genes (acsl4, gpx4, and xct) and iron storage related genes (tf, fth, and fpn) in zebrafish embryos. Through in vitro verification, it was found that IBC also caused oxidative stress and increased Fe2+ content in HepG2 cells. IBC caused depolarization of mitochondrial membrane potential (MMP) and reduction of mitochondrial ATP, as well as altered expression of ACSl4, SLC7A11, GPX4, and FTH1 proteins. Treatment of HepG2 cells with ferrostatin‐1 could reverse the effect of IBC. Targeting the System Xc−‐GSH‐GPX4 pathway of ferroptosis and preventing oxidative stress damage might offer a theoretical foundation for practical therapy and prevention of IBC‐induced hepatotoxicity. Isobavachalcone (IBC) is a flavonoid component in the traditional Chinese medicine Psoraleae Fructus, which is widely used. However, IBC has toxicity and requires further in‐depth research. This study found that IBC was hepatotoxic to zebrafish embryos and HepG2 cells, while causing an imbalance in antioxidant capacity, an increase in Fe2+ content, and ferroptosis through the System Xc−‐ GSH‐GPX4 pathway. This provides a theoretical basis for the application and detoxification of IBC. [ABSTRACT FROM AUTHOR]

Replicating maternal care and incubating octopus embryos artificially is advantageous to improve access to embryonic stages, split and share broods, and reduce the required space to culture large quantities of embryos. However, without female care and adequate rearing systems, the risk of bacterial and fungal infections can be high. This study evaluated the potential effects of low‐concentration sodium hypochlorite (NaOCl) as a disinfectant on embryonic survival, hatchling survival, and growth. Embryos of a holobenthic octopus, Amphioctopus fangsiao, and of a merobenthic octopus, Octopus sinensis, were disinfected with 0.004% NaOCl for 3 min either once at the start (IB), at the start and halfway point (RB), and without disinfection (control). Survival of A. fangsiao embryos differed among treatments initially, but the final number of hatchings did not differ among treatments. No differences in the final survival for O. sinensis embryos were observed among the three treatments. Wet weight and growth for A. fangsiao juveniles did not differ among treatments at any point. In contrast, initial and final dry weight for O. sinensis paralarvae from the control treatment were heavier compared to the IB and RB treatments. These results suggest that NaOCl used as disinfectant has a species‐specific effect on early hatchlings depending on the octopus life history. [ABSTRACT FROM AUTHOR]

Developmental toxicity studies help to understand the impact of a pollutant on this crucial phase of the living organisms which can affect their population dynamics. Zebrafish has become an ideal model for studying environmental and embryo toxicity. The present study was carried out using zebrafish embryos for assessing the environmental toxicity of Di(2-ethylhexyl) phthalate (DEHP) which is universally considered to be an omnipresent environmental contaminant as it is the most widely used plasticizer. The embryos were exposed to DEHP for a range of five concentrations of 0.2, 20, 80, 140 and 200 μg/L for the duration of 96 hours. The treatment resulted in increased mortality and decreased hatch rate, hatchability and heartrate. It also induced teratogenic endpoints like yolk sac edema, pericardial edema and spinal deformity in the embryos which increased in dose and time dependent manner. [ABSTRACT FROM AUTHOR]

Ichthyosporea is an underexplored group of unicellular eukaryotes closely related to animals. Thanks to their phylogenetic position, genomic content, and development through a multinucleate coenocyte reminiscent of some animal embryos, the members of Ichthyosporea are being increasingly recognized as pivotal to the study of animal origins. We delve into the existing knowledge of Ichthyosporea, identify existing gaps and discuss their life cycles, genomic insights, development, and potential to be model organisms. We also discuss the underestimated diversity of ichthyosporeans, based on new environmental data analyses. This review will be an essential resource for researchers venturing into the study of ichthyosporeans. Ichthyosporea are unicellular eukaryotes crucial for understanding animal origins and evolution. This Review outlines the history and recent advancements in ichthyosporean biology, genomics, and genetics, and provides insight into their environmental diversity. [ABSTRACT FROM AUTHOR]

The first embryonic division represents a starting point for the development of a new individual. In many species, tight control over the first embryonic division ensures its accuracy. However, the first division in humans is often erroneous and can impair embryo development. To delineate the spatiotemporal organization of the first mitotic division typical for normal human embryo development, we systematically analyzed a unique timelapse dataset of 300 IVF embryos that developed into healthy newborns. The zygotic division pattern of these best-quality embryos was compared to their siblings that failed to implant or arrested during cleavage stage. We show that division at the right angle to the juxtaposed pronuclei is preferential and supports faithful zygotic division. Alternative configurations of the first mitosis are associated with reduced clustering of nucleoli and multinucleation at the 2-cell stage, which are more common in women of advanced age. Collectively, these data imply that orientation of the first division predisposes human embryos to genetic (in)stability and may contribute to aneuploidy and age-related infertility. The first zygotic cell division is more error-prone in humans than in other species, though it is not clear why these errors occur or how embryos recover. Here they show that orientation of the first cleavage is closely related to genetic stability in human embryos. [ABSTRACT FROM AUTHOR]

Background Objective Materials and methods Results Discussion and conclusion Sperm‐borne microRNAs play a pivotal role in influencing essential cellular processes during fertilization, impacting the quality of embryo development. Dysregulated microRNA profiles have been associated with compromised embryonic development and increased incidences of pregnancy loss.This study aimed to investigate the potential associations between the abundance of miR‐34c‐5p and miR‐191‐3p in human spermatozoa with sperm quality, as well as with embryo quality and metabolic performance during in vitro development.Thirteen couples who underwent a total of 13 cycles participated in this study. The sperm quality was assessed using conventional methods following World Health Organization guidelines. Quantitative polymerase chain reaction was employed to measure microRNA abundance in spermatozoa. Embryos were categorized as good, lagging, or bad based on morphokinetic evaluation. Evaluation of embryo metabolic performance involved tracking changes in specific metabolites within the cultured media using nuclear magnetic resonance spectroscopy. Statistical analysis was conducted to explore the correlation between microRNA abundance in human spermatozoa and all other collected data.Our findings revealed a negative correlation between the abundance of miR‐34c‐5p (but not miR‐191‐3p) and total sperm motility, potentially mediated by the modulation of key signaling pathways. Additionally, higher levels of miR‐34c‐5p in spermatozoa were strongly associated with the consumption or release of key metabolites by developing embryos, particularly those linked with lipid and glucose metabolism, suggesting enhanced metabolic performance, while miR‐191‐3p was mostly associated with glucose consumption. Concurrently, only miR‐34c‐5p content in spermatozoa correlated with higher embryo quality.This study provides evidence suggesting that the abundance of miR‐34c‐5p in spermatozoa is correlated not only with total sperm motility but also with markers of embryo developmental competence, highlighting the potential significance of this sperm microRNA content as a biomarker in assisted reproduction. [ABSTRACT FROM AUTHOR]

All land plants—the embryophytes—produce multicellular embryos, as do other multicellular organisms, such as brown algae and animals. A unique characteristic of plant embryos is their immobile and confined nature. Their embedding in maternal tissues may offer protection from the environment, but also physically constrains development. Across the different land plants, a huge discrepancy is present between their reproductive structures whilst leading to similarly complex embryos. Therefore, we review the roles that maternal tissues play in the control of embryogenesis across land plants. These nurturing, constraining, and protective roles include both direct and indirect effects. In this review, we explore how the maternal surroundings affect embryogenesis and which chemical and mechanical barriers are in place. We regard these questions through the lens of evolution, and identify key questions for future research. [ABSTRACT FROM AUTHOR]

Global climate change has already brought noticeable alterations to multiple regions of our planet, including increased CO2 concentrations and changes in temperature. Several important steps of plant growth and development, such as embryogenesis, can be affected by such environmental changes; for instance, they affect how stored nutrients are used during early stages of seed germination during the transition from heterotrophic to autotrophic metabolism—a critical period for the seedling's survival. In this article, we briefly describe relevant processes that occur during embryo maturation and account for nutrient accumulation, which are sensitive to environmental change. Most of the nutrients stored in the seed during its development—including carbohydrates, lipids, and proteins, depending on the species—accumulate during the seed maturation stage. It is also known that iron, a key micronutrient for various electron transfer processes in plant cells, accumulates during embryo maturation. The existing literature indicates that climate change can not only affect the quality of the seed, in terms of total nutritional content, but also affect seed production. We discuss the potential effects of temperature and CO2 increases from an embryo-autonomous point of view, in an attempt to separate the effects on the parent plant from those on the embryo. [ABSTRACT FROM AUTHOR]

Summary The initial free expansion of the embryo within a seed is at some point inhibited by its contact with the testa, resulting in its formation of folds and borders. Although less obvious, mechanical forces appear to trigger and accelerate seed maturation. However, the mechanistic basis for this effect remains unclear. Manipulation of the mechanical constraints affecting either the in vivo or in vitro growth of oilseed rape embryos was combined with analytical approaches, including magnetic resonance imaging and computer graphic reconstruction, immunolabelling, flow cytometry, transcriptomic, proteomic, lipidomic and metabolomic profiling. Our data implied that, in vivo, the imposition of mechanical restraints impeded the expansion of testa and endosperm, resulting in the embryo's deformation. An acceleration in embryonic development was implied by the cessation of cell proliferation and the stimulation of lipid and protein storage, characteristic of embryo maturation. The underlying molecular signature included elements of cell cycle control, reactive oxygen species metabolism and transcriptional reprogramming, along with allosteric control of glycolytic flux. Constricting the space allowed for the expansion of in vitro grown embryos induced a similar response. The conclusion is that the imposition of mechanical constraints over the growth of the developing oilseed rape embryo provides an important trigger for its maturation. [ABSTRACT FROM AUTHOR]

Time-lapse imaging systems for embryo incubation and selection might improve outcomes of in-vitro fertilisation (IVF) and intracytoplasmic sperm injection (ICSI) treatment due to undisturbed embryo culture conditions, improved embryo selection, or both. However, the benefit remains uncertain. We aimed to evaluate the effectiveness of time-lapse imaging systems providing undisturbed culture and embryo selection, and time-lapse imaging systems providing only undisturbed culture, and compared each with standard care without time-lapse imaging. We conducted a multicentre, three-parallel-group, double-blind, randomised controlled trial in participants undergoing IVF or ICSI at seven IVF centres in the UK and Hong Kong. Embryologists randomly assigned participants using a web-based system, stratified by clinic in a 1:1:1 ratio to the time-lapse imaging system for undisturbed culture and embryo selection (time-lapse imaging group), time-lapse imaging system for undisturbed culture alone (undisturbed culture group), and standard care without time-lapse imaging (control group). Women were required to be aged 18–42 years and men (ie, their partners) 18 years or older. Couples had to be receiving their first, second, or third IVF or ICSI treatment and could not participate if using donor gametes. Participants and trial staff were masked to group assignment, embryologists were not. The primary outcome was live birth. We performed analyses using the intention-to-treat principle and reported the main analysis in participants with primary outcome data available (full analysis set). The trial is registered on the International Trials Registry (ISRCTN17792989) and is now closed. 1575 participants were randomly assigned to treatment groups (525 participants per group) between June 21, 2018, and Sept 30, 2022. The live birth rates were 33·7% (175/520) in the time-lapse imaging group, 36·6% (189/516) in the undisturbed culture group, and 33·0% (172/522) in the standard care group. The adjusted odds ratio was 1·04 (97·5% CI 0·73 to 1·47) for time-lapse imaging arm versus control and 1·20 (0·85 to 1·70) for undisturbed culture versus control. The risk reduction for the absolute difference was 0·7 percentage points (97·5% CI –5·85 to 7·25) between the time-lapse imaging and standard care groups and 3·6 percentage points (–3·02 to 10·22) between the undisturbed culture and standard care groups. 79 serious adverse events unrelated to the trial were reported (n=28 in time-lapse imaging, n=27 in undisturbed culture, and n=24 in standard care). In women undergoing IVF or ICSI treatment, the use of time-lapse imaging systems for embryo culture and selection does not significantly increase the odds of live birth compared with standard care without time-lapse imaging. Barts Charity, Pharmasure Pharmaceuticals, Hong Kong OG Trust Fund, Hong Kong Health and Medical Research Fund, Hong Kong Matching Fund. [ABSTRACT FROM AUTHOR]

The direction of left-right visceral asymmetry is conserved in vertebrates. Deviations of the standard asymmetric pattern are rare, and the underlying mechanisms are not understood. Here, we use the teleost Astyanax mexicanus, consisting of surface fish with normal left-oriented heart asymmetry and cavefish with high levels of reversed right-oriented heart asymmetry, to explore natural changes in asymmetry determination. We show that Sonic Hedgehog (Shh) signaling is increased at the posterior midline, Kupffer's vesicle (the teleost left-right organizer) is enlarged and contains longer cilia, and the number of dorsal forerunner cells is increased in cavefish. Furthermore, Shh increase in surface fish embryos induces asymmetric changes resembling the cavefish phenotype. Asymmetric expression of the Nodal antagonist Dand5 is equalized or reversed in cavefish, and Shh increase in surface fishmimics changes in cavefish dand5 asymmetry. Shh decrease reduces the level of right-oriented heart asymmetry in cavefish. Thus, naturally occurring modifications in cavefish heart asymmetry are controlled by the effects of Shh signaling on left-right organizer function. [ABSTRACT FROM AUTHOR]

The reproductive process in Octopus maya was analyzed to establish the amount of reactive oxygen species that the embryos inherit from females, during yolk synthesis. At the same time, respiratory metabolism, ROS production, and the expression of some genes of the antioxidant system were monitored to understand the ability of embryos to neutralize maternal ROS and those produced during development. The results indicate that carbonylated proteins and peroxidized lipids (LPO) were transferred from females to the embryos, presumably derived from the metabolic processes carried out during yolk synthesis in the ovary. Along with ROS, females also transferred to embryos glutathione (GSH), a key element of the antioxidant defense system, thus facilitating the neutralization of inherited ROS and those produced during development. Embryos are capable of neutralizing ROS thanks to the early expression of genes such as catalase (CAT) and superoxide dismutase (SOD), which give rise to the synthesis of enzymes when the circulatory system is activated. Also, it was observed that the levels of the routine metabolic rate of embryos are almost as high as those of the maximum activity metabolism, which leads, on the one hand, to the elevated production of ROS and suggests that, at this stage of the life cycle in octopuses, energy production is maximum and is physically limited by the biological properties inherent to the structure of embryonic life (oxygen transfer through the chorion, gill surface, pumping capacity, etc.). Due to its role in regulating vascularization, a high expression of HIf-1A during organogenesis suggests that circulatory system development has begun in this phase of embryo development. The results indicate that the routine metabolic rate and the ability of O. maya embryos to neutralize the ROS are probably the maximum possible. Under such circumstances, embryos cannot generate more energy to combat the free radicals produced by their metabolism, even when environmental factors such as high temperatures or contaminants could demand excess energy. [ABSTRACT FROM AUTHOR]

In vitro embryo production (IVP) is of great importance to the porcine industry, as well as for basic research and biomedical applications. Despite the large efforts made in laboratories worldwide to address suboptimal culture conditions, porcine IVP remains inefficient. Nobiletin (Nob, 5,6,7,8,3′,4′ hexamethoxyflavone) supplementation to in vitro culture (IVC) medium, enhances in vitro embryo development in various species. However, its impact on the quality and developmental capacity of in vitro-produced pig embryos is yet to be established. This study evaluated the effects of different concentrations (2.5 and 5 μM) of Nob during the early culture of in vitro -produced pig embryos on embryo developmental competence, mitochondrial activity, lipid content, intracellular Reactive Oxygen Species (ROS) and Glutathione (GSH) content, Total Cell Number (TCN) per blastocyst, and expression of genes related to embryo development, quality and oxidative stress. Embryos cultured in medium without Nob supplementation and in medium supplemented with 0.01 % dimethyl sulfoxide (DMSO-vehicle for Nob) constituted the Control and DMSO groups, respectively. Embryo development rates were evaluated on Days 2, 6 and 7 of IVC. Additionally, a representative group of embryos was selected to assess mitochondrial activity, lipid, ROS and GSH content (on Days 2 and 6 of IVC), TCN assessment and gene expression analyses (on Day 6 of IVC). No significant differences were observed in any of the parameters evaluated on Day 2 of IVC. In contrast, embryos cultured under the presence of Nob 2.5 showed higher developmental rates on Days 6 and 7 of IVC. In addition, Day 6 embryos showed increased mitochondrial activity, with decreased levels of ROS and GSH in the Nob 2.5 group compared to the other groups. Both Nob 2.5 and Nob 5 embryos showed higher TCN compared to the Control and DMSO groups. Furthermore, Nob 2.5 and Nob 5 upregulated the expression of Superoxide dismutase type 1 (SOD1) and Glucose-6-phosphate dehydrogenase (G6PDH) genes, which could help to counteract oxidative stress during IVC. In conclusion, the addition of Nob during the first 48 h of IVC increased porcine embryo development rates and enhanced their quality, including the upregulation of relevant genes that potentially improved the overall efficiency of the IVP system. • In vitro embryo production is of great importance to the porcine industry and biomedical applications. • The efficiency of porcine in vitro embryo production falls below optimal levels. • Nobiletin supplementation in vitro increased porcine embryo development and quality. • Nobiletin is a potential solution for addressing ROS-related issues in porcine in vitro embryo production. [ABSTRACT FROM AUTHOR]

This retrospective study aimed at identifying factors that contribute to the success of equine in vitro embryo production by intracytoplasmic sperm injection (ICSI). A total of 7993 ovum pick-up (OPU) sessions were performed, totaling 2540 donor mares and semen from 396 stallions. Oocytes were aspirated at multiple sites in Brazil and were sent to the laboratory, within 6 h from OPU, in pre-maturation medium where they were in vitro matured (IVM) followed by ICSI and in vitro embryo culture for 7–8 days. The number of recovered oocytes, matured oocytes, cleaved embryos and blastocysts were used to explore the effect of age and breed of the donor mare, time of year in which the mare was aspirated and phase of the estrous cycle on the day of follicular aspiration. Mares between 6 and 15 years old were superior to other age groups in most parameters evaluated, including the average number of blastocysts per OPU. The impact of age was similar when evaluated within two breeds, American Quarter Horse (AQHA) and Warmblood mares. We observed that breed (AQHA, Warmblood, Crioulo, Lusitano and Mangalarga) had an important effect on most of the parameter evaluated, including number of oocytes recovered, blastocysts produced per OPU, and blastocyst rates. The overall impact of season was less pronounced than age and breed, with the only statistically significant difference being a higher rate of oocyte maturation during the summer season. Finally, most of the parameters evaluated were superior in follicular phase mares, with or without dominant follicle than luteal phase mares. In conclusion, this retrospective study revealed that breed, age, season and stage of estrous at the time of OPU are all important parameters for the success of equine embryo production by ICSI. This technology enables producing embryos all-year-round from mares of different breeds and ages from OPU-derived oocytes collected at multiple sites. • Embryo produced per OPU was greater in mares between 6 and 15 years old. • The time of the year did not influence the number of oocytes recovered. • Mares in estrus produce more embryos per opu. [ABSTRACT FROM AUTHOR]

The research is aimed to elucidate the role of plant hormones in regulating the development of hybrid embryos in Hydrangea macrophylla. Fruits from the intraspecific cross of H. macrophylla 'Otaksa' × 'Coerulea' were selected at the globular, heart, and torpedo stages of embryo development. Transcriptome sequencing and differential gene expression analysis were conducted. The results showed that fruit growth followed a single "S-shaped growth curve, with globular, heart, and torpedo embryos appearing at 30, 40, and 50 d post-pollination, respectively, and the embryo maintaining the torpedo shape from 60 to 90 d. A total of 12,933 genes was quantified across the three developmental stages, with 3359, 3803, and 3106 DEGs in the S1_vs_S2, S1_vs_S3, and S2_vs_S3 comparisons, respectively. Among these, 133 genes related to plant hormone biosynthesis and metabolism were differentially expressed, regulating the synthesis and metabolism of eight types of plant hormones, including cytokinin, auxin, gibberellin, abscisic acid, and jasmonic acid. The pathways with the most differentially expressed genes were cytokinin, auxin, and gibberellin, suggesting these hormones may play crucial roles in embryo development. In the cytokinin pathway, CKX (Hma1.2p1_0579F.1_g182670.gene, Hma1.2p1_1194F.1_g265700.gene, and NewGene_12164) genes were highly expressed during the globular embryo stage, promoting rapid cell division in the embryo. In the auxin pathway, YUC (Hma1.2p1_0271F.1_g109005.gene and Hma1.2p1_0271F.1_g109020.gene) genes were progressively up-regulated during embryo growth; the early response factor AUX/IAA (Hma1.2p1_0760F.1_g214260.gene) was down-regulated, while the later transcriptional activator ARF (NewGene_21460, NewGene_21461, and Hma1.2p1_0209F.1_g089090.gene) was up-regulated, sustaining auxin synthesis and possibly preventing the embryo from transitioning to maturity. In the gibberellin pathway, GA3ox (Hma1.2p1_0129F.1_g060100.gene) expression peaked during the heart embryo stage and then declined, while the negative regulator GA2ox (Hma1.2p1_0020F.1_g013915.gene) showed the opposite trend; and the gibberellin signaling repressor DELLA (Hma1.2p1_1054F.1_g252590.gene) increased over time, potentially inhibiting embryo development and maintaining the torpedo shape until fruit maturity. These findings preliminarily uncover the factors affecting the development of hybrid H. macrophylla embryos, laying a foundation for further research into the regulatory mechanisms of H. macrophylla hybrid embryo development. [ABSTRACT FROM AUTHOR]

Acute myeloid leukemia (AML) is characterized by the abnormal proliferation and differentiation arrest of myeloid progenitor cells. The clinical treatment of AML remains challenging. Promoting AML cell differentiation is a valid strategy, but effective differentiation drugs are lacking for most types of AML. In this study, we generated Tg(drl:hoxa9) zebrafish, in which hoxa9 overexpression was driven in hematopoietic cells and myeloid differentiation arrest was exhibited. Using Tg(drl:hoxa9) embryos, we performed chemical screening and identified four FDA-approved drugs, ethacrynic acid, khellin, oxcarbazepine, and alendronate, that efficiently restored myeloid differentiation. The four drugs also induced AML cell differentiation, with ethacrynic acid being the most effective. By an RNA-seq analysis, we found that during differentiation, ethacrynic acid activated the IL-17 and MAPK signaling pathways, which are known to promote granulopoiesis. Furthermore, we found that ethacrynic acid enhanced all-trans retinoic acid (ATRA)-induced differentiation, and both types of signaling converged on the IL-17/MAPK pathways. Inhibiting the IL-17/MAPK pathways impaired ethacrynic acid and ATRA-induced differentiation. In addition, we showed that ethacrynic acid is less toxic to embryogenesis and less disruptive to normal hematopoiesis than ATRA. Thus, the combination of ethacrynic acid and ATRA may have broader clinical applications. In conclusion, through zebrafish-aided screening, our study identified four drugs that can be repurposed to induce AML differentiation, thus providing new agents for AML therapy. [ABSTRACT FROM AUTHOR]

Repetition of the same vocal stimulus during vocal learning may result in habituation. Therefore, selection may favor vocal tutors that produce vocal stimuli with characteristics that reduce the risk of habituation. Superb fairywren Malurus cyaneus mothers produce a two‐element (A and signature B) call to embryos, but embryos only produce one element type (B) after hatching. Why do mothers use the A element to embryos? We broadcast calls with one (B) or two (AB) element types and measured embryo response. Embryos habituated to calls with one element type and remained responsive to calls with both. We conclude that signal characteristics in tutors may guide learning to retain pupil attention during learning. [ABSTRACT FROM AUTHOR]

With the flourishing of spatial omics technologies, alignment and stitching of slices becomes indispensable to decipher a holistic view of 3D molecular profile. However, existing alignment and stitching methods are unpractical to process large-scale and image-based spatial omics dataset due to extreme time consumption and unsatisfactory accuracy. Here we propose SANTO, a coarse-to-fine method targeting alignment and stitching tasks for spatial omics. SANTO firstly rapidly supplies reasonable spatial positions of two slices and identifies the overlap region. Then, SANTO refines the positions of two slices by considering spatial and omics patterns. Comprehensive experiments demonstrate the superior performance of SANTO over existing methods. Specifically, SANTO stitches cross-platform slices for breast cancer samples, enabling integration of complementary features to synergistically explore tumor microenvironment. SANTO is then applied to 3D-to-3D spatiotemporal alignment to study development of mouse embryo. Furthermore, SANTO enables cross-modality alignment of spatial transcriptomic and epigenomic data to understand complementary interactions. Spatial omics technologies require alignment and stitching of slices for a 3D molecular profile. Here, the authors present SANTO, a coarse-to-fine method that rapidly determines spatial positions and overlap regions, then refines them, enabling integration across platforms and modalities. [ABSTRACT FROM AUTHOR]

High pressure shear band formation is a critical phenomenon in energetic materials due to its influence on both mechanical strength and mechanochemical activation. While shear banding is known to occur in a variety of these materials, the governing dynamics of the mechanisms are not well defined for molecular crystals. We conduct molecular dynamics simulations of shock wave induced shear band formation in the energetic material 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) to assess shear band nucleation processes. We find, that at high pressures, the initial formation sites for shear bands, "embryos", form in excess and rapidly lower deviatoric stresses prior to shear band formation and growth. This results in the suppression of plastic deformation. A local cluster analysis is used to quantify and contrast this mechanism with a more typical shear banding seen at lower pressures. These results demonstrate a mechanism that is reversible in nature and that supersedes shear band formation at increased pressures. We anticipate that these results will have a broad impact on the modeling and development of high-strain rate application materials such as those for high explosives and hypersonic systems. [ABSTRACT FROM AUTHOR]

Mammalian oocytes accumulate more than ten thousand mRNAs, of which three to four thousand mRNAs are translationally repressed. The timings and sites of translational activation of these dormant mRNAs are crucial for promoting oocyte maturation and embryonic development. How these mRNAs are accumulated and distributed in oocytes is therefore a fundamental issue to be explored. A method that enables visualization of mRNA molecules with high resolution in a simple manner would be valuable for understanding how oocytes accumulate and regulate the dormant mRNAs. We have developed a highly sensitive whole-mount in situ hybridization method using in vitro-synthesized RNA probes and the tyramide signal amplification (TSA) system optimized for mouse oocytes and embryos. By using this method, Pou5f1/Oct4, Emi2, and cyclin B1 mRNAs were detected in immature oocytes and 2-cell stage embryos. Confocal microscopy showed that these mRNAs formed granular structures in the oocyte cytoplasm. The structures of Pou5f1/Oct4 and cyclin B1 mRNAs persisted in 2-cell stage embryos. Pou5f1/Oct4 RNA granules exhibited a solid-like property in immature oocytes and became liquid-like droplets in 2-cell stage embryos. Double-staining of cyclin B1 mRNA with Emi2 or Pou5f1/Oct4 mRNA revealed that these mRNAs were distributed as different RNA granules without overlapping each other and that the size of cyclin B1 RNA granules tended to be larger than that of Emi2 RNA granules. The structures and distribution patterns of these mRNAs were further analyzed by N-SIM super-resolution microscopy. This analysis revealed that the large-sized RNA granules consist of many small-sized granules, suggesting the accumulation and regulation of dormant mRNAs as basal-sized RNA granules. The method established in this study can easily visualize the structure and distribution of mRNAs accumulated in mammalian oocytes and embryos with high sensitivity and super-resolution. This method is useful for investigating the cellular and molecular mechanisms of translational control of mRNAs by which maturation and early developmental processes are promoted. [ABSTRACT FROM AUTHOR]

Objective: To explore the optimal models for predicting the formation of high-quality embryos in Poor Ovarian Response (POR) Patients with Progestin-Primed Ovarian Stimulation (PPOS) using machine learning algorithms. Methods: A retrospective analysis was conducted on the clinical data of 4,216 POR cycles who underwent in vitro fertilization (IVF) / intracytoplasmic sperm injection (ICSI) at Sichuan Jinxin Xinan Women and Children's Hospital from January 2015 to December 2021. Based on the presence of high-quality cleavage embryos 72 h post-fertilization, the samples were divided into the high-quality cleavage embryo group (N = 1950) and the non-high-quality cleavage embryo group (N = 2266). Additionally, based on whether high-quality blastocysts were observed following full blastocyst culture, the samples were categorized into the high-quality blastocyst group (N = 124) and the non-high-quality blastocyst group (N = 1800). The factors influencing the formation of high-quality embryos were analyzed using logistic regression. The predictive models based on machine learning methods were constructed and evaluated accordingly. Results: Differential analysis revealed that there are statistically significant differences in 14 factors between high-quality and non-high-quality cleavage embryos. Logistic regression analysis identified 14 factors as influential in forming high-quality cleavage embryos. In models excluding three variables (retrieved oocytes, MII oocytes, and 2PN fertilized oocytes), the XGBoost model performed slightly better (AUC = 0.672, 95% CI = 0.636–0.708). Conversely, in models including these three variables, the Random Forest model exhibited the best performance (AUC = 0.788, 95% CI = 0.759–0.818). In the analysis of high-quality blastocysts, significant differences were found in 17 factors. Logistic regression analysis indicated that 13 factors influence the formation of high-quality blastocysts. Including these variables in the predictive model, the XGBoost model showed the highest performance (AUC = 0.813, 95% CI = 0.741–0.884). Conclusion: We developed a predictive model for the formation of high-quality embryos using machine learning methods for patients with POR undergoing treatment with the PPOS protocol. This model can help infertility patients better understand the likelihood of forming high-quality embryos following treatment and help clinicians better understand and predict treatment outcomes, thus facilitating more targeted and effective interventions. [ABSTRACT FROM AUTHOR]

Background: In recent years, with benefits from the continuous improvement of clinical technology and the advantage of fertility preservation, the application of embryo cryopreservation has been growing rapidly worldwide. However, amidst this growth, concerns about its safety persist. Numerous studies have highlighted the elevated risk of perinatal complications linked to frozen embryo transfer (FET), such as large for gestational age (LGA) and hypertensive disorders during pregnancy. Thus, it is imperative to explore the potential risk of embryo cryopreservation and its related mechanisms. Methods: Given the strict ethical constraints on clinical samples, we employed mouse models in this study. Three experimental groups were established: the naturally conceived (NC) group, the fresh embryo transfer (Fresh-ET) group, and the FET group. Blastocyst formation rates and implantation rates were calculated post-embryo cryopreservation. The impact of FET on fetal growth was evaluated upon fetal and placental weight. Placental RNA-seq was conducted, encompassing comprehensive analyses of various comparisons (Fresh-ET vs. NC, FET vs. NC, and FET vs. Fresh-ET). Results: Reduced rates of blastocyst formation and implantation were observed post-embryo cryopreservation. Fresh-ET resulted in a significant decrease in fetal weight compared to NC group, whereas FET reversed this decline. RNA-seq analysis indicated that the majority of the expression changes in FET were inherited from Fresh-ET, and alterations solely attributed to embryo cryopreservation were moderate. Unexpectedly, certain genes that showed alterations in Fresh-ET tended to be restored in FET. Further analysis suggested that this regression may underlie the improvement of fetal growth restriction in FET. The expression of imprinted genes was disrupted in both FET and Fresh-ET groups. Conclusion: Based on our experimental data on mouse models, the impact of embryo cryopreservation is less pronounced than other in vitro manipulations in Fresh-ET. However, the impairment of the embryonic developmental potential and the gene alterations in placenta still suggested it to be a risky operation. [ABSTRACT FROM AUTHOR]

Aim. To investigate the effect of the triggering method on the results of fresh embryo transfer in patients who underwent gonadotropin‐releasing hormone antagonist cycles. Methods. The study was conducted retrospectively at a university‐based tertiary reproductive center. The sample consisted of a total of 295 patients, of whom 111 were in the human chorionic gonadotropin (hCG) trigger group and 184 were in the dual trigger group. The main outcome measure of this study was the live birth rate, and secondary outcomes were the implantation rate, clinical pregnancy rate, miscarriage rate, and good‐quality embryo rate. Results. Patient demographics and baseline characteristics did not significantly differ between the dual and hCG trigger groups. The results also indicated statistically nonsignificant differences between the two groups in terms of the number of oocytes retrieved (p > 0.05), the number of mature oocytes (p > 0.05), and the fertilization rate (p > 0.05). The number of good‐quality embryos (p = 0.002) was higher in the dual trigger group compared with the hCG trigger group. However, the rates of clinical pregnancy and live births did not significantly differ between the groups (p > 0.05). Conclusions. Although the number of total and high‐quality embryos obtained was higher in the dual trigger group, there were no significant differences between the two groups in terms of pregnancy outcomes. The fresh embryo transfer yielded similar rates of implantation and live births in both trigger groups. [ABSTRACT FROM AUTHOR]

Objective: To explore the effects of insulin resistance (IR) on embryo quality and pregnancy outcomes inwomen with or without polycystic ovary syndrome (PCOS) undergoing in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI). Methods: A retrospective cohort study concerning patients with/without PCOS who received gonadotropin-releasing hormone (GnRH)-antagonist protocol for IVF/ICSI from January 2019 to July 2022 was conducted. All the patients included underwent oral glucose tolerance test plus the assessment of insulin release within 6 months before the controlled ovarian stimulation. The Matsuda Index was calculated to diagnose IR. Two populations (PCOS and non-PCOS) were included and each was divided into IR and non-IR groups and analyzed respectively. The primary outcome was the high-quality day 3 embryo rate. Results: A total of 895 patients were included (751 with PCOS and 144 without PCOS). For patients with PCOS, the IR group had a lower high-quality day 3 embryo rate (36.8% vs. 39.7%, p=0.005) and available day 3 embryo rate (67.2% vs. 70.6%, p<0.001). For patients without PCOS, there was no significant difference between the IR and non-IR groups in high-quality day 3 embryo rate (p=0.414) and available day 3 embryo rate (p=0.560). There was no significant difference in blastocyst outcomes and pregnancy outcomes for both populations. Conclusion: Based on the diagnosis by the Matsuda Index, IR may adversely affect the day 3 embryo quality in patients with PCOS but not pregnancy outcomes. In women without PCOS, IR alone seems to have less significant adverse effects on embryo quality than in patients with PCOS. Better-designed studies are still needed to compare the differences statistically between PCOS and non-PCOS populations. [ABSTRACT FROM AUTHOR]

Syngnathid fishes often experience a reduction in brood size and an increase in immunity during pregnancy. Researchers have studied the polygamous broad-nosed pipefish (Syngnathus typhle) and revealed that some eggs from low-quality females in the male's brood pouch serve as nurse eggs that are absorbed by the father. It is unclear whether nurse eggs also exist in other syngnathid fishes, especially in monogamous syngnathid fishes. In monogamous syngnathid fishes, the male pouch only carries eggs from a single female. Thus, the question remains: do some eggs of monogamous syngnathid fishes also serve as nurse eggs? And if so, are these nurse eggs impaired eggs, or are they viable eggs that are consumed by the brooding father? In the present study, we used the monogamous lined seahorse (Hippocampus erectus) and asked whether nurse eggs exist in this species. We also explored whether nurse eggs potentially originate from viable versus inviable eggs. Using isotope labeling, we found that nutrients from embryos could be transferred to brooding fathers. Furthermore, we also found that brooding fathers with limited food had a higher isotope content and a smaller brood size compared to individuals with sufficient food. These results have demonstrated that nurse eggs exist in the lined seahorse, and also suggested that the brooding fathers actively consume viable embryos to absorb nutrients in response to low food availability. These findings help us better understand parent-embryo conflict, filial cannibalism, and male-only care in teleost fishes. [ABSTRACT FROM AUTHOR]

Living cells have spontaneous ultraweak photon emission derived from metabolic reactions associated with physiological conditions. The ORCA-Quest CMOS camera (Hamamatsu Photonics, Japan) is a highly sensitive and essential tool for photon detection; its use with a microscope incubator (Olympus) enables the detection of photons emitted by embryos with the exclusion of harmful visible light. With the application of the second law of thermodynamics, the low-entropy energy absorbed and used by embryos can be distinguished from the higher-entropy energy released and detectable in their environment. To evaluate higher-entropy energy data from embryos, we developed a unique algorithm for the calculation of the entropy-weighted spectral fractal dimension, which demonstrates the self-similar structure of the energy (photons) released by embryos. Analyses based on this structure enabled the distinction of living and degenerated mouse embryos, and of frozen and fresh embryos and the background. This novel detection of ultra-weak photon emission from mouse embryos can provide the basis for the development of a photon emission embryo control system. The ultraweak photon emission fingerprints of embryos may be used for the selection of viable specimens in an ideal dark environment. [ABSTRACT FROM AUTHOR]

Building on previous studies, this essay discusses the use of embryological images and analogies in Anaximander, Empedocles, Democritus, and Lucretius. It pursues their intertextual connections arguing that in ancient philosophy embryology was not only relevant for conceiving the early formation of the cosmos as has been claimed so far, but that it also shaped the conception of the primeval rise of animal life and the living processes of plants. [ABSTRACT FROM AUTHOR]