Articles de revues : « Embryonic stages »

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Chang, Kai-Hsin, Angelique M. Nelson, Hua Cao, Linlin Wang, Betty Nakamoto, Carol B. Ware et Thalia Papayannopoulou. « Definitive-like erythroid cells derived from human embryonic stem cells coexpress high levels of embryonic and fetal globins with little or no adult globin ». Blood 108, n^o 5 (1 septembre 2006) : 1515–23. http://dx.doi.org/10.1182/blood-2005-11-011874.

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Human embryonic stem cells are a promising tool to study events associated with the earliest ontogenetic stages of hematopoiesis. We describe the generation of erythroid cells from hES (H1) by subsequent processing of cells present at early and late stages of embryoid body (EB) differentiation. Kinetics of hematopoietic marker emergence suggest that CD45+ hematopoiesis peaks at late D14EB differentiation stages, although low-level CD45- erythroid differentiation can be seen before that stage. By morphologic criteria, hES-derived erythroid cells were of definitive type, but these cells both at mRNA and protein levels coexpressed high levels of embryonic (ϵ) and fetal (γ) globins, with little or no adult globin (β). This globin expression pattern was not altered by the presence or absence of fetal bovine serum, vascular endothelial growth factor, Flt3-L, or coculture with OP-9 during erythroid differentiation and was not culture time dependent. The coexpression of both embryonic and fetal globins by definitive-type erythroid cells does not faithfully mimic either yolk sac embryonic or their fetal liver counterparts. Nevertheless, the high frequency of erythroid cells coexpressing embryonic and fetal globin generated from embryonic stem cells can serve as an invaluable tool to further explore molecular mechanisms.

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Merchan, Jaime A., Francisco S. Del Campo et J. Rueda. « Sensorineural Interactions in Embryonic Stages ». Acta Oto-Laryngologica 101, sup429 (janvier 1986) : 11–15. http://dx.doi.org/10.3109/00016488609122724.

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Niva, Cintia C., et Miriam Becker. « Embryonic external morphogenesis of Rhammatocerus conspersus (Bruner) (Orthoptera : Acrididae : Gomphocerinae) and determination of the diapausing embryonic stage ». Anais da Sociedade Entomológica do Brasil 27, n^o 4 (décembre 1998) : 557–83. http://dx.doi.org/10.1590/s0301-80591998000400010.

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The grasshopper Rhammatocerus conspersus (Bruner) (Orthoptera: Acrididae: Gomphocerinae) is an occasional pest in pasturelands of Rio Grande do Sul State. It is a univoltine species with an embryonic diapause. Nymphal and adult stages occur during the warmer months (November-March). Eggs were dissected periodically for characterization of embryonic external morphogenesis in 1994 and 1995. Ten embryonic stages were illustrated. Two diapausing stages were verified in R. conspersus: one at 25% and another at 50% of total embryonic development.

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Prokop, A., et G. M. Technau. « The origin of postembryonic neuroblasts in the ventral nerve cord of Drosophila melanogaster ». Development 111, n^o 1 (1 janvier 1991) : 79–88. http://dx.doi.org/10.1242/dev.111.1.79.

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Embryonic and postembryonic neuroblasts in the thoracic ventral nerve cord of Drosophila melanogaster have the same origin. We have traced the development of threefold-labelled single precursor cells from the early gastrula stage to late larval stages. The technique allows in the same individual monitoring of progeny cells at embryonic stages (in vivo) and differentially staining embryonic and postembryonic progeny within the resulting neural clone at late postembryonic stages. The analysis reveals that postembryonic cells always appear together with embryonic cells in one clone. Furthermore, BrdU labelling suggests that the embryonic neuroblast itself rather than one of its progeny resumes proliferation as a postembryonic neuroblast. A second type of clone consists of embryonic progeny only.

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Boag, Brian, et Gregor Yeates. « Post-embryonic growth of longidorid nematodes ». Nematology 4, n^o 8 (2002) : 883–89. http://dx.doi.org/10.1163/156854102321122494.

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AbstractTo investigate changes in body size of Longidoridae during growth, we used published dimensions of stages to calculate volumes of the juvenile and adult stages of 33 species. A consistent increase in body volume between the juvenile stages was found with proportionally more growth occurring between the smaller stages. In species where three, rather than four, juvenile stages are present, the ultimate size of adults was correspondingly smaller. In the Heteroderidae, greatest growth occurs in later stages and this indicates different adaptations to plant parasitism. Analysis of further groups of free-living and parasitic nematodes is required to increase understanding of body growth and life histories, both within and between families.

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Kimmel, Charles B., William W. Ballard, Seth R. Kimmel, Bonnie Ullmann et Thomas F. Schilling. « Stages of embryonic development of the zebrafish ». Developmental Dynamics 203, n^o 3 (juillet 1995) : 253–310. http://dx.doi.org/10.1002/aja.1002030302.

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Praskova, E., E. Voslarova, Z. Siroka, L. Plhalova, S. Macova, P. Marsalek, V. Pistekova et Z. Svobodova. « Assessment of diclofenac LC50 reference values in juvenile and embryonic stages of the zebrafish (Danio rerio) ». Polish Journal of Veterinary Sciences 14, n^o 4 (1 décembre 2011) : 545–49. http://dx.doi.org/10.2478/v10181-011-0081-0.

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Assessment of diclofenac LC50 reference values in juvenile and embryonic stages of the zebrafish (Danio rerio) The aim of the study was to compare the acute toxicity of diclofenac to juvenile and embryonic stages of the zebrafish (Danio rerio). Acute toxicity tests were performed on the aquarium fish Danio rerio, which is one of the model organisms most commonly used in toxicity testing. The tests were performed using a semi-static method according to OECD guideline No. 203 (Fish, acute toxicity test). Embryo toxicity tests were performed in zebrafish embryos (Danio rerio) in compliance with OECD No. 212 methodology (Fish, short-term toxicity test on embryo and sac-fry stages). The results were subjected to a probit analysis using the EKO-TOX 5.2 programme to determine 96hLC50 and 144hLC50 (median lethal concentration, 50% mortality after a 96 h or 144 h interval, respectively) values of diclofenac. The statistical significance of the difference between LC50 values in juvenile and embryonic stages of Danio rerio was tested using the Mann-Whitney non-parametric test implemented in the Unistat 5.1 programme. The LC50 mean value of diclofenac was 166.6 ± 9.8 mg/L in juvenile Danio rerio, and 6.11 ± 2.48 mg/L in embryonic stages of Danio rerio. The study demonstrated a statistically higher sensitivity to diclofenac (P<0.05) in embryonic stages compared to the juvenile fish.

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Sharma, Adita, Tanushri Ghorai, Shivendra Kumar et P. P. Srivastava. « Differential impact of monsoon and late monsoon season on embryonic development of Amur Carp (Cyprinus carpio haematopterus) ». emergent Life Sciences Research 08, n^o 02 (2022) : 72–76. http://dx.doi.org/10.31783/elsr.2022.827276.

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The embryonic development of Amur carp (Cyprinus carpio haematopterus) throughout the monsoon and post-monsoon seasons is compared in this research work. During the regular and late breeding seasons, the study identifies the most critical features of the monsoon season that affect Amur carp embryonic development. The effects of temperature changes on embryonic development were evaluated by observing the morphological characteristics of the embryos and identifying the embryonic stages that eventually determined the impacts of temperature changes on embryonic development. According to present study, the development stages of eggs in the regular season are shorter than in the late monsoon season. Initially, eggs grow at the same time, but late monsoon eggs require more time to develop.

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Ikeda, Wataru, Hiroyuki Nakanishi, Jun Miyoshi, Kenji Mandai, Hiroyoshi Ishizaki, Miki Tanaka, Atushi Togawa et al. « Afadin ». Journal of Cell Biology 146, n^o 5 (6 septembre 1999) : 1117–32. http://dx.doi.org/10.1083/jcb.146.5.1117.

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Afadin is an actin filament–binding protein that binds to nectin, an immunoglobulin-like cell adhesion molecule, and is colocalized with nectin at cadherin-based cell–cell adherens junctions (AJs). To explore the function of afadin in cell–cell adhesion during embryogenesis, we generated afadin−/− mice and embryonic stem cells. In wild-type mice at embryonic days 6.5–8.5, afadin was highly expressed in the embryonic ectoderm and the mesoderm, but hardly detected in the extraembryonic regions such as the visceral endoderm. Afadin−/− mice showed developmental defects at stages during and after gastrulation, including disorganization of the ectoderm, impaired migration of the mesoderm, and loss of somites and other structures derived from both the ectoderm and the mesoderm. Cystic embryoid bodies derived from afadin−/− embryonic stem cells showed normal organization of the endoderm but disorganization of the ectoderm. Cell–cell AJs and tight junctions were improperly organized in the ectoderm of afadin−/− mice and embryoid bodies. These results indicate that afadin is highly expressed in the ectoderm- derived cells during embryogenesis and plays a key role in proper organization of AJs and tight junctions of the highly expressing cells, which is essential for proper tissue morphogenesis.

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Cheng, Yu-Rong, Ching-Yi Lin et Jr-Kai Yu. « Embryonic and post-embryonic development in the parasitic copepod Ive ptychoderae (Copepoda : Iviidae) : Insights into its phylogenetic position ». PLOS ONE 18, n^o 3 (7 mars 2023) : e0281013. http://dx.doi.org/10.1371/journal.pone.0281013.

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Parasitic copepods are frequently discovered in many marine animals, and they exhibit great species diversity with remarkable morphological adaptations to their parasitic lifestyle. Similar to their free-living relatives, parasitic copepods usually develop through complex life cycle, but they eventually transform into a modified adult form with reduced appendages. Although the life cycle and distinct larval stages have been described in a few species of parasitic copepods, particularly those infecting commercially valuable marine animals (such as fishes, oysters, and lobsters), very little is known about the developmental process of the species that transformed into extremely simplified adult body plan. This paucity also causes some difficulties when investigating the taxonomy and phylogeny of this kind of parasitic copepods. Here we describe the embryonic development and a series of sequential larval stages of a parasitic copepod, Ive ptychoderae, which is a vermiform endoparasite living inside the hemichordate acorn worms. We devised laboratory regimes that enable us raising large quantity of embryos and free living larvae, and obtaining post-infested I. ptychoderae samples from the host tissues. Using defined morphological features, the embryonic development of I. ptychoderae can be categorized into eight stages (1-, 2-, 4-, 8-, 16- cell stages, blastula, gastrula, and limb bud stages) and the post-embryonic development comprises six larval stages (2 naupliar and 4 copepodid stages). Based on the comparisons of morphological characters in the nauplius stage, our results provide evidence to support that the Ive-group is more closely related to the Cyclopoida, which represents one of the two major clades that contain many highly transformed parasitic copepods. Thus, our results help to resolve the problematic phylogenetic position of the Ive-group in previous study based on analysis using 18S rDNA sequences. Combining with more molecular data, future comparative analyses on the morphological features of copepodid stages will further refine our understanding of the phylogenetic relationships of parasitic copepods.

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Fopp-Bayat, Dorota, Tomasz Ciemniewski et Beata Irena Cejko. « Embryonic Development and Survival of Siberian Sturgeon × Russian Sturgeon (Acipenser baerii × Acipenser gueldenstaedtii) Hybrids Cultured in an RAS System ». Animals 13, n^o 1 (22 décembre 2022) : 42. http://dx.doi.org/10.3390/ani13010042.

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The aim of this study was to describe the selected stages of embryonic development in Siberian sturgeon (Acipenser baerii) and hybrids of Siberian sturgeons and Russian sturgeons (Acipenser baerii × Acipenser gueldenstaedtii). For this purpose, embryos representing nine distinct developmental stages (stage 1—2.0 hpf, stage 2—5.5 hpf, stage 3—13.0 hpf, stage 4—20.0 hpf, stage 5—24.0 hpf, stage 6—26.0 hpf, stage 7—35.0 hpf, stage 8—55.0 hpf, and, stage 9—160.0 hpf; hpf—hours postfertilization) were sampled from each group (group A, group B, and group C) during incubation. Stages of embryogenesis were identified based on a 30-point scale of embryonic development in sturgeons. A total of 13 developmental stages were identified, including early cleavage, blastula formation, early and late gastrulation, onset of neurulation, beginning of organogenesis, and prelarvae. During gastrulation, the survival of hybrid embryos was highest in group B (93.8%) and lowest in group A (86.7%). Embryonic deformation was not observed during experimental incubation. The archived data relating to the embryonic development of Siberian sturgeon × Russian sturgeon hybrids could be applied to identify the individual stages of embryogenesis in hybrid sturgeons during egg incubation.

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de Frutos, C., R. Laguna-Barraza, P. Bermejo-Alvarez, D. Rizos et A. Gutierrez-Adan. « 91 SPERMATOZOA TELOMERE LENGTH DETERMINES EMBRYONIC TELOMERE LENGTH BEFORE EMBRYONIC GENOME ACTIVATION ». Reproduction, Fertility and Development 25, n^o 1 (2013) : 193. http://dx.doi.org/10.1071/rdv25n1ab91.

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A critical issue for species integrity is the existence of a telomere elongation program during embryogenesis that ensures sufficient telomere reserves in mammalian newborns. Two different mechanisms have been reported to act on telomere elongation during early embryogenesis: first, the telomerase, the ribonucleoprotein that adds telomeric repeats onto the chromosome ends, known to be responsible for the telomere lengthening at the morula-blastocyst transition in mice and bovine; second, in laboratory mice strains, mature oocytes increase the length of their relatively short telomeres between the 1-cell and 2-cell stages by a recombination or ALT-like pathway. In contrast, spermatozoa, the terminally differentiated male gametes, exhibit a very long telomere length (TL). The aim of this study was to clarify the potential role of the spermatozoa TL in the telomere lengthening occurring between oocyte and the 2-cell stage. For this purpose, we used 2 mouse species known to differ greatly in their TL [Mus musculus (hybrid C57CBAF1), long TL, and Mus spretus, short TL]. First, we compared relative TL in sperm samples from 5 age-matched males of each species by quantitative real-time PCR, with the numbers of telomere repeats being normalized, to the amount of DNA present in the sample (based on quantification of the Rn18S gene) by the comparative Ct method. Then, 1- and 2-cell embryos were produced by fertilizing Mus musculus oocytes with either Mus musculus or Mus spretus spermatozoa. The TL analysis in oocytes, zygotes, or 2-cell embryos was carried out by absolute quantification of telomere repeats by qPCR and normalized to the highest Ct observed value. Twenty to thirty samples per stage were analyzed, with each sample consisting in 2 matured oocytes, 2 zygotes, or one 2-cell embryo, to allow comparisons between stages. One-way ANOVA was used for statistical analysis. Mus spretus spermatozoa had significantly shorter telomeres than did Mus musculus (1.0 ± 0.1 v. 9.0 ± 1.5, respectively; P ≤ 0.01). The TL increased after fertilization from oocyte to zygote and 2-cell embryo stages in Mus musculus (1.0 ± 0.1, 1.5 ± 0.1, and 2.4 ± 0.2, respectively; P ≤ 0.01). In contrast, no differences were found in the TLs between the 3 stages in Mus spretus hybrids (oocyte: 1.0 ± 0.1; zygote: 1.0 ± 0.1; and 2-cell embryo: 1.0 ± 0.1), indicating that no elongation occurred after fertilization with spermatozoa with short telomeres. Herein, we demonstrated that before embryonic genome activation occurs, spermatozoa TL determines TL of the early embryo, suggesting that spermatozoon telomeres may act as recombination templates for early telomere lengthening right after syngamia.

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Alibardi, Lorenzo, et Michael B. Thompson. « Morphogenesis of shell and scutes in the turtle Emydura macquarii ». Australian Journal of Zoology 47, n^o 3 (1999) : 245. http://dx.doi.org/10.1071/zo99001.

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Formation of the scutes and dermis of the embryonic shell of the turtle Emydura macquarii was studied using light and electron microscopy. Shell morphogenesis begins at embryonic stage 15 and the shape of the shell is mostly completed by embryonic stage 19. The carapace anlagen arises as a thickening of the skin in the dorsal part of the mid-trunk region between the anterior and posterior limbs. This thickening extends ventro-laterally to form ridges at the margins of the carapace. Each ridge forms as a thick epidermal placode over a condensation of mesenchymal cells. The epidermis behind the advancing margins of the carapace is cuboidal or columnar but does not form placodes. The margins of the carapace expand rapidly in all directions. The plastron anlagen is derived from epidermal cells localised in the latero-ventral regions between the fore- and hind-limbs. Plastron placodes are present laterally, while the mid-ventral and central epidermis remains cuboidal or columnar but does not form placodes at embryonic stage 16. The plastron thickening rapidly moves from a latero-ventral position to a flat ventral position between embryonic stages 16 and 19. Dermal–epidermal anchoring complexes occur throughout placodes of both the carapace and plastron, but are rare in non-placode areas. The accumulation of a dense mesenchyme beneath the shell epidermis forms a dermal cushion that surrounds the body cavity. The superficial dermis close to the epidermis is made of mesenchymal fibroblasts at embryonic stage 19, although the inner-most areas contain bipolar fibroblasts and extracellular fibrils. Scutes with serrations at their borders form as invaginations of the epidermis into the dermis in the mid-dorsal areas of the embryo at embryonic stages 18–19. Dermal–epidermal anchoring complexes are located around the infoldings that form the scutes of the hinge region. The epidermis of the shell has 2–3 suprabasal cells at embryonic stages 19–22, and lacks keratinisation before embryonic stage 22 when it has 4–6 suprabasal layers with 2–3 external layers made of flat cells. The dermis thickens and has numerous collagen fibrils after embryonic stage 19. The formation of dermal bones begins at embryonic stage 18–19 in the plastron. Only small areas of the carapace near to the bridge have begun to form dermal bone at embryonic stage 19. Calcification begins at embryonic stage 19, but is still incomplete at embryonic stages 24–25.

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Galis, Frietson, et Barry Sinervo. « Divergence and convergence in early embryonic stages of metazoans ». Contributions to Zoology 71, n^o 1-3 (2002) : 101–13. http://dx.doi.org/10.1163/18759866-0710103008.

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The early stages of organogenesis in metazoans differ drastically between higher order taxa such as phyla and classes. The segmented germ band stage in insects, the nauplius stage of crustaceans, and the neurula/pharyngula stage in vertebrates are examples of this diversification. In striking contrast with this divergence, is the similarity of these stages within these taxa, i.e., within insects, crustaceans, and vertebrates. The early stages of organogenesis, or phylotypic stages, have, thus, remained very similar in most species since the evolutionary origin of the taxa. These phylotypic stages are considerably more similar to each other than to the earlier stages of cleavage and gastrulation. Cleavage and gastrulation stages display not only great variability, but also striking examples of apparent convergence among species in different phyla, for example in the many cases of epiblastic cleavage in yolk-rich eggs. This leads to the paradoxical situation that the overall similarity of cleavage and gastrulation stages is in general higher among metazoans than of the early stages of organogenesis, but within phyla and classes the situation is the reverse. We discuss data on cleavage, gastrulation, and early organogenesis and evaluate possible causes for conservation, homoplasy, and diversification in an attempt to throw light on this paradoxical situation. In addition, we discuss a hypothesis that has been proposed to explain the diversity of early stages of organogenesis at the level of metazoans and the similarity within many phyla and classes.

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Kamemizu, Chizuru, et Toshihiko Fujimori. « Distinct dormancy progression depending on embryonic regions during mouse embryonic diapause† ». Biology of Reproduction 100, n^o 5 (1 février 2019) : 1204–14. http://dx.doi.org/10.1093/biolre/ioz017.

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Abstract Many mammalian species undergo embryonic diapause and suspend development at the blastocyst stage before implantation, which is also known as delayed implantation. We studied the process of how mouse embryos enter a dormancy status at a cellular level. Immunofluorescent analysis of differentiation markers for epiblast, primitive endoderm, and trophectoderm suggested that cell differentiation status was maintained during 7 days in diapause. To understand the progression of cellular dormancy during diapause, we examined the expression of a transgenic cell cycle marker Fucci2 and Ki67 by antibody staining, in addition to direct counting of nuclei in embryos. From these analyses, embryos during diapause were categorized into four stages by cell number and cell cycle. Cell cycle arrest occurred from the ab-embryonic region and from the trophectoderm to the ICM in the embryonic side. We also observed cell cycle transition by live imaging of Fucci2 embryos during the reactivation in culture from dormant status. Cell cycle was initially recovered from the embryonic side of embryos and eventually spread throughout the whole embryo. We also found that embryos in later stages of diapause required a longer period of time for reactivation. From these observations, it was shown that entrance into and exit from dormant status varied depending on cell types and location of cells in an embryo. These results suggest that embryonic diapause includes multiple steps and the mechanisms involved in cellular dormancy may be distinct between embryonic regions.

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Shangpliang, P. Wankitlang, Rupa Nylla K. Hooroo, Graham Bakynson Ranee, Sudhanya Ray Hajong, Annu Kumari et Eugene Lyngkhoi. « Exploring Altitude's Influence : Contrasting Embryonic Development of Hyla annectans Jerdon in High and Low Altitude Environments ». UTTAR PRADESH JOURNAL OF ZOOLOGY 45, n^o 7 (21 mars 2024) : 1–9. http://dx.doi.org/10.56557/upjoz/2024/v45i73967.

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The study investigated the embryonic development of Hyla annectans Jerdon, a frog species, at high and low altitude breeding sites of Meghalaya, North East India. Results revealed significant differences in the duration of embryonic development and hatching between the two altitudes. Embryos at low altitude sites exhibited a faster development, hatching approximately four days earlier than those at high altitude sites. Early embryonic stages displayed similar characteristics in size between the two sites, but distinct differences emerged during later stages, notably in stages associated with heart development, muscular response, and gill circulation. Furthermore, metamorphosis completion varied between altitudes, with a shorter duration observed at low altitude compared to high altitude. Environmental conditions, particularly water properties, also differed significantly between the two sites. Water temperature and free carbon dioxide levels were higher at low altitude, while pH and dissolved oxygen levels were higher at high altitude. These findings suggest a potential influence of altitudinal gradients as environmental factors on embryonic development in H. annectans.

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Schill, R. O., et G. B. Fritz. « Desiccation tolerance in embryonic stages of the tardigrade ». Journal of Zoology 276, n^o 1 (septembre 2008) : 103–7. http://dx.doi.org/10.1111/j.1469-7998.2008.00474.x.

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Mrak, Polona, Urban Bogataj, Jasna Štrus et Nada Žnidaršič. « Cuticle morphogenesis in crustacean embryonic and postembryonic stages ». Arthropod Structure & ; Development 46, n^o 1 (janvier 2017) : 77–95. http://dx.doi.org/10.1016/j.asd.2016.11.001.

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OHTA, SHUNSUKE, YOSHIAKI SUZUKI, WAJIRO HARA, SHIGEHARU TAKIYA et TOSHIHARU SUZUKI. « Fibroin Gene Transcription in the Embryonic Stages of the Silkworm, Bombyx mori. (fibroin gene/ faithful transcription/ embryonic stages/Bombyx mori) ». Development, Growth and Differentiation 30, n^o 3 (juin 1988) : 293–99. http://dx.doi.org/10.1111/j.1440-169x.1988.00293.x.

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Narimatsu, Yoji, et Hiroyuki Munehara. « Spawn date dependent survival and growth in the early life stages of Hypoptychus dybowskii (Gasterosteiformes) ». Canadian Journal of Fisheries and Aquatic Sciences 56, n^o 10 (1 octobre 1999) : 1849–55. http://dx.doi.org/10.1139/f99-118.

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The effects of spawn date on survival and growth during the embryonic, larval, and juvenile stages of a coastal fish, Hypoptychus dybowskii (Gasterosteiformes), were examined. Monitoring of embryos using SCUBA showed that the embryonic period decreased as the season progressed and the hatching rate was lowest for the early-spawn cohort (EC). Analysis of otolith daily growth increments indicated that EC larvae had much lower survival and growth rates than larvae of middle-spawn (MC) and late-spawn cohorts (LC), but there were no large differences in either rate among juveniles of the three cohorts. EC suffered the highest mortality rates in the embryonic and larval stages; these high rates were linked with slow development and growth, probably caused by below-optimum water temperatures. EC fish grew over a longer period and reached larger body size than MC and LC fish. These results suggest that intraannual variations in growth pattern and survival rate in the embryonic and larval stages were caused by spawn date differences, which favored the LC in the study year, but the EC might have a size-dependent advantage in survivorship and reproductive success during the postjuvenile stages.

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Heffernan, Corey, Penny A. F. Whiley, Antonia Milionis, Paul J. Verma, Michael K. Holland, David A. Jans et Nancy T. D'Cruz. « Lineage-specific expression of heterochromatin protein 1γ in post-compaction, in vitro-produced bovine embryos ». Reproduction, Fertility and Development 22, n^o 6 (2010) : 1022. http://dx.doi.org/10.1071/rd09265.

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Heterochromatin protein 1γ (HP1γ) is a highly conserved regulator of euchromatic and heterochromatic gene expression. Mammalian HP1γ is essential for both successful preimplantation embryo development and maintenance of pluripotency in embryonic stem cells in vitro. Here, we describe HP1γ protein localisation in matured (MII) bovine oocytes and IVF preimplantation embryos at defined developmental stages. HP1γ is expressed in post-compaction embryos in a highly lineage-specific pattern. In embryonic stages preceding the maternal to embryonic transition (MET), HP1γ protein was primarily cytoplasmic, whereas in 8–16-cell embryos (post MET), HP1γ was primarily nuclear. Lineage-specific patterns of HP1γ protein localisation become evident from compaction, being restricted to peripheral, extraembryonic cells at the morula and blastocyst stages (Days 7–9). Surprisingly, we detected HP1γ mRNA in both embryonic and extraembryonic cells in blastocysts by fluorescence in situ hybridisation. In trophectoderm cells, HP1γ protein was localised in specific patterns at the mitotic and interphase stages of the cell cycle. These results demonstrate lineage- and cell cycle-specific patterns of HP1γ protein localisation in the post-compaction, preimplantation bovine embryo and raise interesting questions about the role of HP1γ in early embryo development.

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Fu, Yao, Jia-Jun Xu, Xu-Lei Sun, Hao Jiang, Dong-Xu Han, Chang Liu, Yan Gao, Bao Yuan et Jia-Bao Zhang. « Function of JARID2 in bovines during early embryonic development ». PeerJ 5 (21 décembre 2017) : e4189. http://dx.doi.org/10.7717/peerj.4189.

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Histone lysine modifications are important epigenetic modifications in early embryonic development. JARID2, which is a member of the jumonji demethylase protein family, is a regulator of early embryonic development and can regulate mouse development and embryonic stem cell (ESC) differentiation by modifying histone lysines. JARID2 can affect early embryonic development by regulating the methylation level of H3K27me3, which is closely related to normal early embryonic development. To investigate the expression pattern of JARID2 and the effect of JARID2-induced H3K27 methylation in bovine oocytes and early embryonic stages, JARID2 mRNA expression and localization were detected in bovine oocytes and early embryos via qRT-PCR and immunofluorescence in the present study. The results showed that JARID2 is highly expressed in the germinal vesicle (GV), MII, 2-cell, 4-cell, 8-cell, 16-cell and blastocyst stages, but the relative expression level of JARID2 in bovine GV oocytes is significantly lower than that at other oocyte/embryonic stages (p < 0.05), and JARID2 is expressed primarily in the nucleus. We next detected the mRNA expression levels of embryonic development-related genes (OCT4, SOX2 and c-myc) after JARID2 knockdown through JARID2-2830-siRNA microinjection to investigate the molecularpathwayunderlying the regulation of H3K27me3 by JARID2 during early embryonic development. The results showed that the relative expression levels of these genes in 2-cell embryos weresignificantly higher than those in the blastocyst stage, and expression levels were significantly increased after JARID2 knockdown. In summary, the present study identified the expression pattern of JARID2 in bovine oocytes and at each early embryonic stage, and the results suggest that JARID2 plays a key role in early embryonic development by regulating the expression of OCT4, SOX2 and c-myc via modification of H3K27me3 expression. This work provides new data for improvements in the efficiency ofin vitroembryo culture as well as a theoretical basis for further studying the regulatory mechanisms involved in early embryonic development.

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Szabo, P., et J. R. Mann. « Expression and methylation of imprinted genes during in vitro differentiation of mouse parthenogenetic and androgenetic embryonic stem cell lines ». Development 120, n^o 6 (1 juin 1994) : 1651–60. http://dx.doi.org/10.1242/dev.120.6.1651.

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Messenger RNA and methylation levels of four imprinted genes, H19, Igf2r, Igf-2 and Snrpn were examined by northern and Southern blotting in mouse parthenogenetic, androgenetic and normal or wild-type embryonic stem cell lines during their differentiation in vitro as embryoid bodies. In most instances, mRNA levels in parthenogenetic and androgenetic embryoid bodies differed from wild type as expected from previously determined patterns of monoallelic expression in midgestation embryos and at later stages of development. These findings implicate aberrant mRNA levels of these genes in the abnormal development of parthenogenetic and androgenetic embryos and chimeras. Whereas complete silence of one of the parental alleles has previously been observed in vivo, we detected some mRNA in the corresponding embryonic stem cell line. This ‘leakage’ phenomenon could be explained by partial erasure, bypass or override of imprints, or could represent the actual activity status at very early stages of development. The mRNA levels of H19, Igf2r and Igf-2 and the degree of methylation at specific associated sequences were correlated according to previous studies in embryos, and thereby are consistent with suggestions that the methylation might play a role in controlling transcription of these genes. Paternal-specific methylation of the H19 promoter region is absent in sperm, yet we observed its presence in undifferentiated androgenetic embryonic stem cells, or before the potential expression phase of this gene in embryoid bodies. As such methylation is likely to invoke a repressive effect, this finding raises the possibility that it is part of the imprinting mechanism of H19, taking the form of a secondary imprint or postfertilization epigenetic modification necessary for repression of the paternal allele.

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García-Guerrero, Marcelo U., Dulce M. Mateos-Guerrero, Juan J. Alpuche-Osorno et Rodolfo B. De los Santos-Romero. « External morphological stages and protein variations along with the embryonic development of the longarm river prawn Macrobrachium tenellum (Smith, 1871) ». Latin American Journal of Aquatic Research 49, n^o 2 (3 mai 2021) : 202–11. http://dx.doi.org/10.3856/vol49-issue2-fulltext-2605.

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A good understanding of a given species' embryology is important to settle the larval rearing bases when juveniles are required for culture purposes or conservation programs. Changes in embryonic morphology, protein concentration, and protein type occurring in prawn eggs were analyzed in the present work. Berried females of Macrobrachium tenellum were collected in the Colotepec River, Oaxaca, Mexico. The eggs were taken from the ovigerous mass and embryonic stages classified by their color. Morphological changes in the embryos allowed identifying six embryonic stages based on color, egg size, and morphological features. Determinations of the protein extract were executed in SDS-PAGE (electrophoresis in polyacrylamide gels) and, subsequently, proteomic analyses were also performed. Protein bands along embryonic development and their molecular weights are presented and commented.

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Manikandan, Priyadharshini, Swapnalee Sarmah et James A. Marrs. « Ethanol Effects on Early Developmental Stages Studied Using the Zebrafish ». Biomedicines 10, n^o 10 (13 octobre 2022) : 2555. http://dx.doi.org/10.3390/biomedicines10102555.

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Fetal alcohol spectrum disorder (FASD) results from prenatal ethanol exposure. The zebrafish (Danio rerio) is an outstanding in vivo FASD model. Early development produced the three germ layers and embryonic axes patterning. A critical pluripotency transcriptional gene circuit of sox2, pou5f1 (oct4; recently renamed pou5f3), and nanog maintain potency and self-renewal. Ethanol affects sox2 expression, which functions with pou5f1 to control target gene transcription. Various genes, like elf3, may interact and regulate sox2, and elf3 knockdown affects early development. Downstream of the pluripotency transcriptional circuit, developmental signaling activities regulate morphogenetic cell movements and lineage specification. These activities are also affected by ethanol exposure. Hedgehog signaling is a critical developmental signaling pathway that controls numerous developmental events, including neural axis specification. Sonic hedgehog activities are affected by embryonic ethanol exposure. Activation of sonic hedgehog expression is controlled by TGF-ß family members, Nodal and Bmp, during dorsoventral (DV) embryonic axis establishment. Ethanol may perturb TGF-ß family receptors and signaling activities, including the sonic hedgehog pathway. Significantly, experiments show that activation of sonic hedgehog signaling rescues some embryonic ethanol exposure effects. More research is needed to understand how ethanol affects early developmental signaling and morphogenesis.

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Ding, Peng, Yueyue Tong, Shu Wu, Xin Yin, Huichao Liu, Xi He, Zehe Song et Haihan Zhang. « The Sexual Effect of Chicken Embryos on the Yolk Metabolites and Liver Lipid Metabolism ». Animals 12, n^o 1 (29 décembre 2021) : 71. http://dx.doi.org/10.3390/ani12010071.

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The metabolic processes of animals are usually affected by sex. Egg yolk is the major nutrient utilized for the growth and development of a chicken embryo. In this study, we explored the differences of yolk metabolites in male and female chicken embryos by LC–MS/MS. Furthermore, we investigated the mRNA expression of lipoprotein lipase (LPL) and fatty acid synthase (FAS) in chicken embryo liver with different sexes in different embryonic stages. The results showed that the nutrient metabolites in the yolk of female chickens were mainly related to lipid metabolism and amino acid metabolism in the early embryonic stage, and vitamin metabolism in the late embryonic stage. The male yolk metabolites were mainly associated with lipid metabolism and nucleic acid metabolism in the early developmental stage, and amino acids metabolism in the late embryonic stage. There was no significant difference in the expression of LPL or FAS in livers of male and female chicken embryos at different embryonic stages. Our results may lead to a better understanding of the sexual effect on yolk nutrient metabolism during chicken embryonic development.

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Liu, Yifan, Long Chen, Fang Meng, Tao Zhang, Jun Luo, Shuang Chen, Huilai Shi, Bingjian Liu et Zhenming Lv. « The Effect of Temperature on the Embryo Development of Cephalopod Sepiella japonica Suggests Crosstalk between Autophagy and Apoptosis ». International Journal of Molecular Sciences 24, n^o 20 (19 octobre 2023) : 15365. http://dx.doi.org/10.3390/ijms242015365.

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Temperature is a crucial environmental factor that affects embryonic development, particularly for marine organisms with long embryonic development periods. However, the sensitive period of embryonic development and the role of autophagy/apoptosis in temperature regulation in cephalopods remain unclear. In this study, we cultured embryos of Sepiella japonica, a typical species in the local area of the East China Sea, at different incubation temperatures (18 °C, 23 °C, and 28 °C) to investigate various developmental aspects, including morphological and histological characteristics, mortality rates, the duration of embryonic development, and expression patterns of autophagy-related genes (LC3, BECN1, Inx4) and apoptosis marker genes (Cas3, p53) at 25 developmental stages. Our findings indicate that embryos in the high-temperature (28 °C) group had significantly higher mortality and embryonic malformation rates than those in the low-temperature (18 °C) group. Furthermore, high temperature (28 °C) shortened the duration of embryonic development by 7 days compared to the optimal temperature (23 °C), while low temperature (18 °C) caused a delay of 9 days. Therefore, embryos of S. japonica were more intolerant to high temperatures (28 °C), emphasizing the critical importance of maintaining an appropriate incubation temperature (approximately 23 °C). Additionally, our study observed, for the first time, that the Early blastula, Blastopore closure, and Optic vesicle to Caudal end stages were the most sensitive stages. During these periods, abnormalities in the expression of autophagy-related and apoptosis-related genes were associated with higher rates of mortality and malformations, highlighting the strong correlation and potential interaction between autophagy and apoptosis in embryonic development under varying temperature conditions.

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Gao, Yuan, Lei Duo, Xiaoshu Zhe, Lingyun Hao, Weiguo Song, Lizhong Gao, Jun Cai et Dongjun Liu. « Developmental Mapping of Hair Follicles in the Embryonic Stages of Cashmere Goats Using Proteomic and Metabolomic Construction ». Animals 13, n^o 19 (30 septembre 2023) : 3076. http://dx.doi.org/10.3390/ani13193076.

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The hair follicle (HF) is the fundamental unit for fleece and cashmere production in cashmere goats and is crucial in determining cashmere yield and quality. The mechanisms regulating HF development in cashmere goats during the embryonic period remain unclear. Growing evidence suggests that HF development involves complex developmental stages and critical events, and identifying the underlying factors can improve our understanding of HF development. In this study, samples were collected from embryonic day 75 (E75) to E125, the major HF developmental stages. The embryonic HFs of cashmere goats were subjected to proteomic and metabolomic analyses, which revealed dynamic changes in the key factors and signalling pathways controlling HF development at the protein and metabolic levels. Gene ontology and the Kyoto Encyclopaedia of Genes and Genomes were used to functionally annotate 1784 significantly differentially expressed proteins and 454 significantly differentially expressed metabolites enriched in different HF developmental stages. A joint analysis revealed that the oxytocin signalling pathway plays a sustained role in embryonic HF development by activating the MAPK and Ca2+ signalling pathways, and a related regulatory network map was constructed. This study provides a global perspective on the mechanism of HF development in cashmere goats and enriches our understanding of embryonic HF development.

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Tattersall, Glenn J., et Nicole Spiegelaar. « Embryonic motility and hatching success of Ambystoma maculatum are influenced by a symbiotic alga ». Canadian Journal of Zoology 86, n^o 11 (novembre 2008) : 1289–98. http://dx.doi.org/10.1139/z08-115.

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To augment O2 supply through the jelly mass and egg capsule, embryonic yellow-spotted salamanders ( Ambystoma maculatum (Shaw, 1802)) take advantage of a unicellular alga, Oophila ambystomatis . Convective currents from surface cilia, however, may also enhance O2 transport, whereas muscular contractions could either enhance delivery or contribute to O2 consumption. Embryonic motion is, therefore, potentially vital to salamander development. We examined embryonic motility across multiple developmental stages, survivorship, and hatching timing in response to different algal levels by rearing salamander egg masses under three different diel light cycles: 24 h dark, 12 h light, and 24 h light per day. Embryos raised in continuous light hatched synchronously and at slightly earlier developmental stages than embryos raised in the dark or in 12 h light per day. We removed eggs at multiple stages to examine embryonic rotation and muscular contraction rates under 180 min periods of both light and dark. Rotational movements occurred more frequently in alga-free than in algae-inhabited eggs, and more frequently in algae-inhabited eggs in the dark than in light. At later developmental stages, muscular contractions were more frequent in embryos from algae-inhabited egg masses in light than those in the dark; thus embryos with less O2 reduced muscular activity, thereby reducing energy consumption when O2 availability was compromised.

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González-Pisani, Ximena, Tamara Rubilar et Enrique Dupré. « Embryonic development of Pachycheles chubutensis (Decapoda : Anomura) ». Journal of the Marine Biological Association of the United Kingdom 89, n^o 6 (3 juin 2009) : 1195–202. http://dx.doi.org/10.1017/s0025315409000678.

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The different stages of embryonic development of the porcellanid crab Pachycheles chubutensis are described, along with the chronology of each stage at 16±1°C. Five different developmental stages (I–V) were recognized including: (i) early cells and 100% of the vitellum; (ii) formation of the embryonic primordium at the animal pole of the egg; (iii) presence of dark pigmentation on the posterior part of the ocular globe; (iv) appearance of chromatophores on mouth parts and in the abdominal zone; and (v) eye pigmentation in circular–oval form, filling the entire surface. The embryonic development lasts from spawning to hatching approximately 21 days, with the second stage being the longest.

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Foucart, Thomas, Benoit Heulin et Olivier Lourdais. « Clutch size influences embryonic stages at oviposition in a lizard with prolonged egg retention ». Amphibia-Reptilia 38, n^o 4 (2017) : 557–61. http://dx.doi.org/10.1163/15685381-00003128.

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We examined the possible interaction between reproductive effort and embryonic stages at oviposition in oviparous form of the lizard Zootoca vivipara. Our results reveal that the percentage of total embryonic development time (%TEDT) reached at oviposition is negatively correlated to clutch size (adjusted to maternal body size). We found no influence of reproductive burden of female (relative clutch mass, RCM) on %TEDT. The significant effect of fecundity supports the hypothesis that a resource limitation such as oxygen may exist for developing embryos in oviducts. The absence of RCM effect suggests that the available space (abdominal burdening of the mother) does not limit the embryonic stages at oviposition.

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Luan, He, Xie, Chen, Mao, Wang, Li et al. « Identification of an Embryonic Cell-Specific Region within the Pineapple SERK1 Promoter ». Genes 10, n^o 11 (1 novembre 2019) : 883. http://dx.doi.org/10.3390/genes10110883.

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Plant tissue culture methods, such as somatic embryogenesis, are attractive alternatives to traditional breeding methods for plant propagation. However, they often suffer from limited efficiency. Somatic embryogenesis receptor kinase (SERK)1 is a marker gene of early somatic embryogenesis in several plants, including pineapple. It can be selectively induced and promotes a key step in somatic embryogenesis. We investigated the embryonic cell-specific transcriptional regulation of AcSERK1 by constructing a series of vectors carrying the GUS（Beta-glucuronidase） reporter gene under the control of different candidate cis-regulatory sequences. These vectors were transfected into both embryonic and non-embryonic callus, and three immature embryo stages and the embryonic-specific activity of the promoter fragments was analyzed. We found that the activity of the regulatory sequence of AcSERK1 lacking −983 nt ~−880 nt, which included the transcription initiation site, was significantly reduced in the embryonic callus of pineapple, accompanied by the loss of embryonic cell-specific promoter activity. Thus, this fragment is an essential functional segment with highly specific promoter activity for embryonic cells, and it is active only from the early stages of somatic embryo development to the globular embryo stage. This study lays the foundation for identifying mechanisms that enhance the efficiency of somatic embryogenesis in pineapple and other plants.

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Degrelle, Séverine A., Kim-Anh Lê Cao, Yvan Heyman, Robin E. Everts, Evelyne Campion, Christophe Richard, Céline Ducroix-Crépy et al. « A small set of extra-embryonic genes defines a new landmark for bovine embryo staging ». REPRODUCTION 141, n^o 1 (janvier 2011) : 79–89. http://dx.doi.org/10.1530/rep-10-0174.

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Axis specification in mouse is determined by a sequence of reciprocal interactions between embryonic and extra-embryonic tissues so that a few extra-embryonic genes appear as ‘patterning’ the embryo. Considering these interactions as essential, but lacking in most mammals the genetically driven approaches used in mouse and the corresponding patterning mutants, we examined whether a molecular signature originating from extra-embryonic tissues could relate to the developmental stage of the embryo proper and predict it. To this end, we have profiled bovine extra-embryonic tissues at peri-implantation stages, when gastrulation and early neurulation occur, and analysed the subsequent expression profiles through the use of predictive methods as previously reported for tumour classification. A set of six genes (CALM1, CPA3, CITED1, DLD, HNRNPDL, and TGFB3), half of which had not been previously associated with any extra-embryonic feature, appeared significantly discriminative and mainly dependent on embryonic tissues for its faithful expression. The predictive value of this set of genes for gastrulation and early neurulation stages, as assessed on naive samples, was remarkably high (93%). In silico connected to the bovine orthologues of the mouse patterning genes, this gene set is proposed as a new trait for embryo staging. As such, this will allow saving the bovine embryo proper for molecular or cellular studies. To us, it offers as well new perspectives for developmental phenotyping and modelling of embryonic/extra-embryonic co-differentiation.

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Beyes, M., N. Nause, M. Bleyer, F. J. Kaup et S. Neumann. « Description of post-implantation embryonic stages in European roe deer (Capreolus capreolus ) after embryonic diapause ». Anatomia, Histologia, Embryologia 46, n^o 6 (27 septembre 2017) : 582–91. http://dx.doi.org/10.1111/ahe.12315.

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Baizabal, José-Manuel, et Luis Covarrubias. « The embryonic midbrain directs neuronal specification of embryonic stem cells at early stages of differentiation ». Developmental Biology 325, n^o 1 (janvier 2009) : 49–59. http://dx.doi.org/10.1016/j.ydbio.2008.09.024.

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Llobat, Lola. « Pluripotency and Growth Factors in Early Embryonic Development of Mammals : A Comparative Approach ». Veterinary Sciences 8, n^o 5 (4 mai 2021) : 78. http://dx.doi.org/10.3390/vetsci8050078.

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The regulation of early events in mammalian embryonic development is a complex process. In the early stages, pluripotency, cellular differentiation, and growth should occur at specific times and these events are regulated by different genes that are expressed at specific times and locations. The genes related to pluripotency and cellular differentiation, and growth factors that determine successful embryonic development are different (or differentially expressed) among mammalian species. Some genes are fundamental for controlling pluripotency in some species but less fundamental in others, for example, Oct4 is particularly relevant in bovine early embryonic development, whereas Oct4 inhibition does not affect ovine early embryonic development. In addition, some mechanisms that regulate cellular differentiation do not seem to be clear or evolutionarily conserved. After cellular differentiation, growth factors are relevant in early development, and their effects also differ among species, for example, insulin-like growth factor improves the blastocyst development rate in some species but does not have the same effect in mice. Some growth factors influence genes related to pluripotency, and therefore, their role in early embryo development is not limited to cell growth but could also involve the earliest stages of development. In this review, we summarize the differences among mammalian species regarding the regulation of pluripotency, cellular differentiation, and growth factors in the early stages of embryonic development.

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Martínez-Rivera, Stephanie, et Bradley G. Stevens. « Embryonic development and fecundity of the red deep-sea crab Chaceon quinquedens (Smith, 1879) (Decapoda : Brachyura : Geryonidae) in the Mid-Atlantic Bight determined by image analysis ». Journal of Crustacean Biology 40, n^o 3 (1 avril 2020) : 230–36. http://dx.doi.org/10.1093/jcbiol/ruaa017.

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Abstract The red deep-sea crab, Chaceon quinquedens (Smith, 1879), has been harvested from the US Atlantic continental shelf since the 1970s, but knowledge about its biology is extremely limited. We describe the stages and seasonality of embryonic development and determine size-specific fecundity for C. quinquedens in the Mid-Atlantic Bight. Samples were collected by trawling aboard research vessels in 2012–2013, and from traps aboard commercial fishing vessels in 2014–2016. Four stages of embryonic development were described: 1) early development, 2) mid-development, 3) late development, and 4) hatching. A relationship between embryonic development stage and egg-mass color was observed. A brooding cycle was proposed after analyzing seasonal changes in the stages of embryonic development. Fecundity was estimated by using an automated imaging method for egg samples during stage 1 and 2. The estimates of fecundity, the number of eggs per brood, ranged from 34,691 to 324,729 for females between 62.6 and 106.2 mm in carapace length (CL). The linear regression showed a positive correlation between fecundity and female body size in CL (R2 = 0.56). This study provides information on reproductive parameters needed to improve fisheries management.

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Lin, Po-Yu, Denny Yang, Chi-Hsuan Chuang, Hsuan Lin, Wei-Ju Chen, Chia-Ying Chen, Trees-Juen Chuang et al. « Comparative Analyses of Single-Cell Transcriptomic Profiles between In Vitro Totipotent Blastomere-like Cells and In Vivo Early Mouse Embryonic Cells ». Cells 10, n^o 11 (10 novembre 2021) : 3111. http://dx.doi.org/10.3390/cells10113111.

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The developmental potential within pluripotent cells in the canonical model is restricted to embryonic tissues, whereas totipotent cells can differentiate into both embryonic and extraembryonic tissues. Currently, the ability to culture in vitro totipotent cells possessing molecular and functional features like those of an early embryo in vivo has been a challenge. Recently, it was reported that treatment with a single spliceosome inhibitor, pladienolide B (plaB), can successfully reprogram mouse pluripotent stem cells into totipotent blastomere-like cells (TBLCs) in vitro. The TBLCs exhibited totipotency transcriptionally and acquired expanded developmental potential with the ability to yield various embryonic and extraembryonic tissues that may be employed as novel mouse developmental cell models. However, it is disputed whether TBLCs are ‘true’ totipotent stem cells equivalent to in vivo two-cell stage embryos. To address this question, single-cell RNA sequencing was applied to TBLCs and cells from early mouse embryonic developmental stages and the data were integrated using canonical correlation analyses. Differential expression analyses were performed between TBLCs and multi-embryonic cell stages to identify differentially expressed genes. Remarkably, a subpopulation within the TBLCs population expressed a high level of the totipotent-related genes Zscan4s and displayed transcriptomic features similar to mouse two-cell stage embryonic cells. This study underscores the subtle differences between in vitro derived TBLCs and in vivo mouse early developmental cell stages at the single-cell transcriptomic level. Our study has identified a new experimental model for stem cell biology, namely ‘cluster 3’, as a subpopulation of TBLCs that can be molecularly defined as near totipotent cells.

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Cecílio, Daniel Simões Santos, Agda Alves Da Rocha et Edilberto Giannotti. « Post-embryonic Development of Mischocyttarus latior (Fox) (Hymenoptera, Vespidae) ». Sociobiology 62, n^o 3 (30 septembre 2015) : 446. http://dx.doi.org/10.13102/sociobiology.v62i3.400.

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Mischocyttarus latior (Fox) occurs in Bolivia and in Brazil and has been recorded in Cerrado areas from southeast Brazil. The objectives of the present study were to describe the immature stages of M. latior, determine the development time of the immature stages and determine which factors affect its duration. Daily mappings were performed from March 1994 to August 1995 in 22 nests. Two nests were also collected and dissected to characterize immatures. Larvae presented five instars and unlike most Mischocyttarus, M. latior has only a single lobe on the abdominal sternite, which is vestigial in third instar, emergent in fourth instar and fully developed in the fifth instar larvae. The mean duration of the immature stages (from egg laying to adult emergence), was 67.38 ± 9.41 days, a longer period than the total duration of the immature stages of other previously studied species. The development time of the immatures was variable, depending on the colony development stage, with development times being quicker in pre-emergence colonies.

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Chen, Jian Hua, Meng Jie Wang, Xue Li, Hai Hua Wang, Huan Gao et Bin Lun Yan. « Characterization and expression patterns of wnt4 in Exopalaemon carinicauda (Holthuis, 1950) (Caridea, Palaemonidae) during embryonic and larval development ». Crustaceana 92, n^o 1 (2019) : 83–94. http://dx.doi.org/10.1163/15685403-00003854.

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Abstract Wnt4 (Wingless-type MMTV integration site family member 4) has been demonstrated to play critical roles in a wide variety of biological processes, including embryonic development, cell proliferation, and differentiation in vertebrates, but its function in crustaceans is still not clear. In the present study, the full-length wnt4 cDNA sequence was cloned and characterized for the ridgetail white prawn Exopalaemon carinicauda. The expression patterns of the wnt4 mRNA in embryos and larvae at different stages were investigated. The tissue distribution showed that wnt4 was obviously expressed in eyestalk and hepatopancreas. During embryonic development, the wnt4 was highly expressed in all developmental stages except the zygote, two-cell stage, and late zoaea stage. The wnt4 mRNA was expressed in Z1-Z5 and post-larval stages. Taken together, the present study indicates that the wnt4 gene may be involved in the regulation of embryonic and larval development in the ridgetail white prawn.

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Guénon, Melanie. « ʿAbd al-Majīd al-Zindānī's iʿjāz ʿilmī Approach : Embryonic Development in Q. 23:12–14 as a Scientific Miracle ». Journal of Qur'anic Studies 21, n^o 3 (octobre 2019) : 32–56. http://dx.doi.org/10.3366/jqs.2019.0398.

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This article focuses on contemporary scientific exegesis of the Qur'an, analysing ʿAbd al-Majīd al-Zindānī's unique model of embryonic development derived from Q. 23:12–14. Since the majority of Muslim legal scholars consider the three main stages of embryonic development mentioned in Q. 23:12–14 to take place within 120 days, this view has been considered as the majority Muslim view in academic research. However, I claim that since the 1980s al-Zindānī has successfully disseminated the perception that the embryonic stages mentioned in the Qur'anic text take place over 40 days. An examination of al-Zindānī's work and publications by the Commission on the Scientific Miracles in the Qur'an and Sunna (CSMQS) demonstrates that al-Zindānī uses an iʿjāz ʿilmī approach (i.e. seeking to establish harmony between the Qur'an and modern natural science) to advocate a new interpretation of the Qur'anic stages of embryonic development in order to validate the connection between modern science and the Qur'an. I argue that his model rests on three hermeneutical strategies: first, the reformulation of Ibn al-Qayyim's (d. 751/1350) model of embryonic development; second, the modification of the last Qur'anic stage from khalq to nashʾa; and third, his preference for the variant of the so-called Ibn Masʿūd ḥadīth canonised in Ṣaḥīḥ Muslim. Accordingly, he does not follow the fiqh tradition and excludes the stage of the embryo's ensoulment from his model. It is this exclusion of the ensoulment and the reformulation of the developmental stages that enables al-Zindānī to align his model with both the Qur'anic text and modern scientific findings.

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UKESHIMA, Atsumi. « Surface Morphology of Quail Ovaries in Late Embryonic Stages ». Okajimas Folia Anatomica Japonica 72, n^o 5 (1995) : 249–57. http://dx.doi.org/10.2535/ofaj1936.72.5_249.

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Subamia, I. Wayan, Media Fitri Isma Nugraha et Slamet Sugito. « EMBRYONIC DEVELOPMENTAL STAGES OF IKAN PALMAS (Polipterus senegalus senegalus) ». Indonesian Aquaculture Journal 3, n^o 2 (31 décembre 2008) : 119. http://dx.doi.org/10.15578/iaj.3.2.2008.119-124.

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The purpose of these observations was to identify the stages of the embryo development of ikan palmas (Polypterus senegalus senegalus) and determine the length of duration of each stage. Broodstocks were cultured in aquaria 6 cm x 72 cm x 50 cm in size. The broodstock were stocked at ratio of 1:1 and fed ad libitum with earthworm, small feed fish (ting sea fish) and golden snail. The Palmas broodstocks here naturally spawned in artificial nests made of split plastic raffia in resembling the aquatic plant found in the natural habitat of ikan palmas. After 21 days of culture period, the broodstock began to lay eggs in gradually for 20 days. The average diameter of the eggs was 25 μm. The embryo developed in 24 hours after fertilization and hatched out three days after the embryo had developed.

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TORRÈS, Suzanne, Françoise HULOT et Claude SEVELLEC. « Early stages of embryonic development in two rabbit genotypes ». Reproduction Nutrition Développement 27, n^o 3 (1987) : 715–19. http://dx.doi.org/10.1051/rnd:19870511.

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Santer, R. M. « THE EMBRYONIC HUMAN BRAIN. AN ATLAS OF DEVELOPMENTAL STAGES. » Brain 123, n^o 7 (1 juillet 2000) : 1534–35. http://dx.doi.org/10.1093/brain/123.7.1534.

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Gribnau, A. A. M. « The embryonic human brain an atlas of developmental stages ». Journal of Chemical Neuroanatomy 8, n^o 4 (mai 1995) : 307–8. http://dx.doi.org/10.1016/0891-0618(95)90009-8.

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Myint, San San, et Aye Khet Soe. « Morphological Embryonic Development Stages of Barbonymus gonionotus (Bleeker, 1850) ». IOP Conference Series : Earth and Environmental Science 416 (28 janvier 2020) : 012003. http://dx.doi.org/10.1088/1755-1315/416/1/012003.

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Fritsch, Helga. « The Embryonic Human Brain : An Atlas of Developmental Stages ». Archives of Neurology 64, n^o 7 (1 juillet 2007) : 1053. http://dx.doi.org/10.1001/archneur.64.7.1053-a.

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Hall, Thomas E., Peter Smith et Ian A. Johnston. « Stages of embryonic development in the Atlantic codGadus morhua ». Journal of Morphology 259, n^o 3 (2004) : 255–70. http://dx.doi.org/10.1002/jmor.10222.

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Murray, Leanne E. « Davis v. Davis : The Embryonic Stages of Procreational Privacy ». Pace Law Review 14, n^o 2 (1 juin 1994) : 567. http://dx.doi.org/10.58948/2331-3528.1387.

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