Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “embryonic development”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources
PubMed2004

Divergent selection for shape of growth curve in Japanese quail. 2. Embryonic development and growth.

1. Embryonic growth and development were analysed using meat type lines of Japanese quail, HG and LG, divergently selected for shape of the growth curve. A total of 1020 embryos of generations 9, 10 or 13 were used for analysis. 2. Considerable inter-line differences were observed in the rate of embryonic development. When compared to HG, LG embryos appeared to be developmentally accelerated during the first 42 h of incubation (larger blastoderm diameter, more somites and higher frequency of more advanced Hamburger-Hamilton stages) as well as at the end of the prenatal period (more embryos with the yolk sac inside the body cavity, shorter incubation period). This corresponded with the trend in postnatal development. 3. Embryonic growth of both lines exhibited an exponential trend. However, considerable inter-line differences were noted in the rate of embryonic growth. Initial growth retardation compensated subsequently by a higher growth rate of HG vs LG quail, characterised the lines after hatching. The same growth pattern repeated three times during the prenatal period (between d 0 and 3, 3 and 8, and 8 and 16). 4. The repeated occurrence of transient decreases in growth rate of the developmentally delayed HG line could be associated with a delayed onset of genetically determined physiological functions mediating utilisation of nutrient supply. 5. Hence, different shapes of growth curves in two genotypes with similar growth potential reveal inter-line differences in physiological age persisting during the whole ontogenesis.

Animals↗
PubMed2002

Detection of early embryonic development in chicken eggs using visible light transmission.

1. In two separate experiments, the possibility of detecting embryonic development in chicken eggs was assessed using the same spectrophotometric method used to detect blood in Table eggs, using a combination of two wavelengths (577 and 610 nm) of the transmission spectrum. 2. In the first experiment, during the first 10 d of incubation, transmission spectra of 30 Hisex White eggs and 30 Hybro eggs were measured daily. 3. In the second experiment, 292 Hisex White eggs were incubated. Seven groups were randomly assigned. Six received an injection of sodium azide (NaN3) at different times during incubation in order to stop embryonic development, and during the first 12 d of incubation the transmission spectrum was measured daily. The acoustic resonance analysis method was also used on a group of uninjected eggs. 4. In the first experiment, it was possible to detect embryonic development from 120 h of incubation onwards in fertile eggs. In the second experiment changes in light transmission due to embryonic development were detected from 108 h of incubation. Detection of embryonic development using the acoustic resonance analysis method in the second experiment was possible only from 120 h of incubation. 5. It was concluded that the detection of embryonic development using visible light transmission is not directly linked with the formation of blood, but with the formation of sub-embryonic fluid, which takes place from 72 h of incubation onwards. This fluid makes the yolk sac translucent so that absorption of light at 577 nm can be detected.

Absorption↗
PubMed2002

Coordinated expression of scleraxis and Sox9 genes during embryonic development of tendons and cartilage.

Embryonic development of tendons is in close association with that of cartilage and bone. Although these tissues are derived from mesenchymal progenitor cells which also give rise to muscle and fat, their fates clearly diverse in early embryonic stages. Transcription factors may play pivotal roles in the process of determination and differentiation of tendon cells as well as other cells in the skeletal system. Scleraxis, a basic helix-loop-helix (bHLH) type transcription factor, is expressed in mesenchymal progenitors that later form connective tissues including tendons. Sox9 is an HMG-box containing transcription factor, which is expressed at high levels in chondrocytes. We hypothesized that the two transcription factors regulate the fate of cells that interact with each other at the interface between the two tissues during divergence of their differentiation pathways. To address this point, we investigated scleraxis and Sox9 mRNA expression during mouse embyogenesis focusing on the coordinated development of tendons and skeletons. In the early stage of mesenchymal tissue development at 10.5 d.p.c. scleraxis and Sox9 transcripts were expressed in the mesenchymal progenitor cells in the appendicular and axial mesenchyme. At 11.5 d.p.c., scleraxis transcripts were observed in the mesenchymal tissue surrounding skeletal primordia which express Sox9. From this stage. seleraxis expression was closely associated with, but distinct from, formation of skeletal primordia. At 13.5 d.p.c., scleraxis was expressed broadly in the interface between muscle and skeletal primordia while Sox9 expression is confined within the early skeletal primordia. Then, at 15.5 d.p.c., scleraxis transcripts were more restricted to tendons. These observations revealed the presence of temporal and spatial association of scleraxis expression during embryonic development of tendon precursor cells in close association with that of Sox9 expression in chondrogenic cells in skeletal tissues.

Animals↗
PubMed2004

Differentiation and morphogenesis of Triatoma infestans (Klug 1834) female gonads. I--post embryonic development.

The post-embryonic development of the female gonads in Triatoma infestans (Hemiptera, Heteroptera), insects of importance in health affairs as harbors and vectors of different tripanosomatidea flagellates, is presented in a complete follow-up since insect hatches from the egg up to the last molt in the fifth instar stage. The detailed description of the morphological changes which occur in each instar as well as careful measurements evaluating its size increase have been analyzed by stereomicroscopy, phase contrast, dark field, and oblique illumination, in order to optimize the observations as well the photographic register of gonad morphology and structure. The analysis was performed on gonad specimens obtained from broods no less than twenty (20) nymph bugs, reared at constant temperature and fed-up regularly. According to the results of our study we can assert that gonad differentiation takes place in early phases of the insect development. Such is the case that first instars nymph's present absolutely and easily recognizably male and female gonads. From the third instar on beside the filament region, the three zones in each ovariole body is distinguished, a differentiation that is more noticeable during the fourth instar where a definite organization is present at the vitelarium. Such a clear cut zone development continues intensively during the fifth instar. Finally at the end of such fifth nymph stage and when the last molt toward adults is prepared, clear signs of ovariole maturation take place since oocytes in early vitelogenesis are found.

Animals↗
PubMed1986

Changes in glucose 6-phosphate dehydrogenase activity in developing embryonic chick skeletal muscle and spinal cord.

Glucose 6-phosphate dehydrogenase (G6PDH) activity was examined in the developing embryonic chick in brachial and lumbar spinal cord and pectoral and leg muscle. Enzyme activity was generally highest at the earliest stage examined, embryonic day 5. The developmental profiles for G6PDH activity in the two muscles were similar: a sharp initial decrease occurred between days 5 and 9, with relatively low levels present by day 18; peaks of G6PDH activity at days 12 and 16 were more prominent in leg muscle. Similar levels of G6PDH were also detected in spinal cord with the developmental profile in the brachial spinal cord resembling that seen in muscle. In lumbar spinal cord, initial G6PDH activity was lower than in brachial spinal cord; the developmental profile, however, resembled that seen in the brachial spinal cord, with an initial drop in enzyme activity seen between days 5 and 7. Neural regulation of G6PDH activity in mature muscle is believed to repress enzyme synthesis. The drop in G6PDH activity observed in embryonic spinal cord and muscle between days 5 and 9 coincides with the initiation of functional neuromuscular contacts. Hence, the normal regulation of G6PDH during embryonic development may involve the repression of G6PDH in spinal cord neurons and muscle, possibly effected by their interaction.

Animals↗
PubMed1998

Vitamin A and embryonic development: an overview.

Vitamin A is an essential micronutrient throughout the life cycle. Its active form, retinoic acid via retinoid receptors, is involved in signal transduction pathways regulating development. Both the lack and excess of vitamin A during embryonic development result in congenital malformations. Approaches to examine the function of vitamin A in embryonic development have included treatment with excess retinoids and the use of retinoid receptor knock-out mice, which have provided important insights into the complexity of the retinoid signaling system. A recently explored model is the retinoid ligand knock-out, i.e., the vitamin A-deficient embryo. Early development can be successfully examined in the vitamin A-deficient avian embryo, in which bioactive retinoids can rescue the deficient genotype as well as phenotype. In this model it has been possible to unequivocally link the physiological function of vitamin A to development of heart, embryonal circulatory and central nervous systems and the regulation of heart asymmetry. Several developmental genes regulated by endogenous vitamin A during early embryogenesis have been identified. Retinoid receptors and their endogenous ligands, the vitamin A-active forms, are present in the early embryo. It is the developmentally regulated biogeneration of the vitamin A-active forms via distinct spatio-temporal metabolic pathways that is critically linked to the initiation of retinoid signal transduction during embryonic development.

Animals↗
PubMed2006

On functions of cholinesterases during embryonic development.

Expression of cholinesterase (ChE) activity during phases of embryonic development is a general phenomenon in embryonic tissues. To elucidate the role(s) of ChEs during embryonic development, one line of research followed the assumption of a primitive muscarinic system involved in morphogenesis (Hohmann et al., 1995). This means that ChE functioning during development fits into the classical cholinergic neurotransmitter system: acetylcholine (ACh), as a signal, binds to ACh receptors and then is degraded by acetylcholinesterase (AChE) as the terminating enzyme. However, this is just one of the possible mechanisms. The other line of research was driven by evidence for noncholinergic functions of ChE proteins (AChE and butyrylcholinesterase [BChE]). There is accumulating data that other sites on AChE could exert nonclassical roles related to cell differentiation, neurite outgrowth, and adhesion.

Acetylcholinesterase↗
PubMed2001

[Effect of temperature, relative humidity and photoperiod on embryonic development and egg hatch of Pirata piraticus].

In this paper, the effects of temperature, relative humidity and photoperiod on embryonic development and egg hatch of Pirata piraticus were investigated. Temperature affected not only the whole course of embryonic development, but also its different phases. At 20 degrees C-35 degrees C, as temperature increased, the embryonic development became faster. The developmental threshold of egg was estimated to be at 11.9 degrees C. The uniform degree of egg hatch was higher at low temperature, while the highest hatching rate was happened at 28 degrees C. In order to study the factors affecting embryonic development and to determine the optimum condition for egg hatch, experiments were arranged by quadratic regression rotation composite design with three factors: temperature (X1), relative humidity (X2) and photoperiod (X3). Three models were built up, and the factors affecting the embryonic development were analyzed. After calculating the hatching rate using the model of hatching rate by computer, the optimum condition for egg hatch of the spider was given: temperature 27 degrees C-28.5 degrees C, relative humidity 94%-97%, and photoperiod 14-17 h.

Animals↗
PubMed2001

A comparative study of embryonic development of Japanese quail selected for different patterns of postnatal growth.

Patterns of early embryonic development have traditionally been viewed as invariant within vertebrate taxa. It has been argued that the specific differences which are found arise during the later stages of development. These differences may be a result of allometry, heterochrony or changes in relative growth rates. To test whether early embryonic development is indeed invariant, or whether selection of adult characteristics can alter embryonic growth, we compared embryonic development in birds selected for different patterns of postnatal growth. Using quail lines selected for high and low body mass, we compared somite formation, and muscle and feather development. We obtained data that showed changes in the rate of myotome formation in the brachial somites which contribute to muscle formation in the limbs and thorax. We think these observations are connected with intraspecific changes in adult morphology, ie., breast muscle size. Our findings suggest that selection for late ontogenetic/adult stages affects early embryonic development.

Journal Article↗
PubMed2001

Gene expression during pre- and peri-implantation embryonic development in pigs.

Embryo technological procedures such as in vitro production and cloning by nuclear transfer are not as advanced in pigs as in cattle and cannot yet be applied under field conditions. The present paper focuses on genome activation in in vivo-derived, in vitro-produced and nuclear transfer pig embryos with special emphasis on the development of embryonic nucleoli, where the ribosomal RNA (rRNA) genes transcribed can be used as markers for genome activity. In addition, contemporary data on gene expression in in vivo-derived pig embryos are reviewed. In in vivo-derived pig embryos, pronounced transcription is initiated at the four-cell stage (the third cell cycle after fertilization), when nucleoli develop. In parallel with the development of the nucleoli as a result of rRNA gene activation, a cascade of other genes is also likely to be transcribed. However, apart from identification of transcripts for the oestrogen receptor at the blastocyst stage, reports on mRNAs resulting from initial transcription of the pig embryonic genome are lacking, in contrast to the situation in cattle and, in particular, mice. More information is available on gene expression during elongation of pig conceptuses, when the genes for steroidogenic enzymes, extracellular matrix receptors, oestrogen receptors, growth factors and their receptors, as well as retinol binding protein and retinoic acid receptors, are expressed. Nucleolus development appears to be disturbed in in vitro-produced pig embryos and in pig embryos reconstructed by nuclear transfer of granulosa cells to enucleated metaphase II oocytes produced by oocyte maturation in vivo or in vitro, which is indicative of disturbances in activation of rRNA genes.

Animals↗
PubMed1979

The biosynthesis of nicotinamide adenine dinucleotide during early stages of frog embryonic development of haploid and diploid embryos.

1. Concentration of NAD during embryonic development of haploid and diploid embryos of frog was followed. NAD content in haploid embryonic forms is twice that in diploid embryos. 2. The variation of the NMN adenylyltransferase activity in the oocytes and during the first states of embryonic development as surveyed in the nuclear soluble fraction and the nuclear insoluble fraction (chromatin). 3. The enzyme activity in the soluble fraction is low during embryonic development and shows higher values in haploid embryos. 4. In the nonfertilized mature oocytes, the NMN adenylyltransferase activity is sixfold higher in the insoluble chromatin fraction than in the soluble fraction. 5. The evolution of the NMN adenylyltransferase in the insoluble chromatin fraction also shows higher values in haploid embryos, as compared with diploid forms.

Animals↗
PubMed2006

Effect of culture-medium supplementation with alpha-mannosidase and/or beta-N-acetyloglucosaminidase on in vitro bovine embryonic development.

Glycosidases are enzymes with a potential role in embryonic development. The objectives of this study were to assess: (a) whether in vitro bovine embryonic development is affected by the addition of beta-N-acetyloglucosaminidase (beta-NAGASE) and/or alpha-mannosidase to the culture medium and (b) whether these enzymes are utilized by bovine embryos during their development in vitro. Bovine embryos were produced using standard methods of IVM, IVF and IVC. Presumptive zygotes were cultured in groups of 20 in 50 microl drops of SOF medium (plus 5% FBS after 24 h culture) incubated in 5% CO2, 5% O2 and 90% N2 at 38.5 degrees C. The groups of zygotes were allocated to four treatments in which the culture medium was supplemented with: (1) beta-NAGASE, (2) alpha-mannosidase, (3) beta-NAGASE plus alpha-mannosidase, and (4) control (no supplement). Embryos were evaluated and samples of culture medium collected and frozen prior to assay for glycosidases at day 7 of culture. The experimental design was a randomised block arrangement of 4 treatments x 7 replicates with 20 zygotes per plot (culture droplet). Data were analysed by ANOVA and presented as mean +/- S.E.M. The osmolarity of the control culture medium was 272 mOsm. This was increased to 279 mOsm by the addition of alpha-mannosidase, 424 mOsm by beta-NAGASE and 337 mOsm with a combination of the two enzymes. The beta-NAGASE supplemented medium and the combined supplement reduced (0%) the development of zygotes to morula or blastocyst stages (P < 0.002) relative to control medium (35.7 +/- 8.4%). Embryo development was also reduced to 21.9 +/- 3.2 (P< 0.002), relative to control, by alpha-mannosidase supplementation. The reduced embryo development in the beta-NAGASE-supplemented medium was attributed to increased osmolarity of the culture medium. Embryos appeared to utilize alpha-mannosidase because its concentration decreased from 600.95 +/- 174.03 IU/l in drops without zygotes/embryos to 211.01 +/- 71.59 IU/l in drops with zygotes/embryos. Other culture media supplementation showed no significant differences between droplets, with or without zygotes/embryos. It was concluded that beta-NAGASE increased medium osmolarity, embryos utilized alpha-mannosidase and both glycosidases (singly or in combination) inhibited the development of bovine zygotes to morulae/blastocysts.

Acetylglucosaminidase↗
PubMed2004

Foregut mesenchyme contributes cells to pancreatic acini during embryonic development in a chick-quail chimera model.

To understand causes of developmental abnormalities of the pancreas, it is essential to understand its normal embryonic development. Current understanding of the development of pancreatic exocrine tissue is that it develops solely from embryonic epithelium, while the role of the surrounding mesenchyme is to signal to this epithelium and form connective tissue. Recent work in our laboratory has shown that pancreatic bud mesenchyme can contribute cells to islets during embryonic development. However, no published studies have investigated in detail whether mesenchyme contributes cells to the exocrine structures of the pancreas. The aim of this study was to investigate whether cells from foregut mesenchyme can contribute to pancreatic acini during embryonic development. Chick-quail chimera recombinant organs were constructed using pancreatic epithelium and mesenchyme from either the pancreas (n=12) or stomach (n=25). These were cultured for 7 days in 3-D collagen gels. The resulting specimens were analysed using morphological criteria and fluorescent immunocytochemistry against pancreatic amylase, insulin, and the quail-specific nucleolar antigen QCPN. Two independent observers determined the origins of acini as either solely epithelial, solely mesenchymal, or of mixed origin. Results are expressed as percentages of total acini identified in each group. Statistical analysis was performed using chi(2) tests (P<0.01 was considered statistically significant). Recombinations of pancreatic epithelium and pancreatic mesenchyme yielded 11 acini, of which 45% were derived from epithelium only, 45% from mesenchyme only, and 10% of mixed origin. Recombinations of pancreatic epithelium and stomach mesenchyme yielded 78 acini, of which 40% were derived from epithelium only, 32% from mesenchyme only, and 28% of mixed origin. When acini with any mesenchymal cellular contribution were considered as a group, there was no significant difference between stomach and pancreatic mesenchymal contribution (P=0.72). This is the first study to demonstrate the cellular contribution of mesenchyme to pancreatic exocrine structures. Our data show that mesenchyme contributes cells to pancreatic acini during development in this model and that mesenchyme derived from stomach and pancreatic sources are both able to form acini.

Animals↗
PubMed1995

RU486 inhibits ovulation, fertilization and early embryonic development in rabbits: in vivo and in vitro studies.

OBJECTIVE: To clarify the role of P in ovulation, fertilization, and early embryonic development using RU486, a potent P receptor blocker. DESIGN: Ovulatory efficiency, IVF, and early embryonic development were evaluated after RU486 administration in vivo and in vitro. SETTING: Research laboratory of a university hospital. PARTICIPANTS: Mature male and female New Zealand white rabbits. INTERVENTIONS: Animals were treated with RU486 or vehicle for 3 days before hCG-induced ovulation. Ovaries treated with hCG to induce ovulation were perfused for 6 hours in vitro with RU486 or vehicle. In vitro fertilization was performed in the presence or absence of RU486. MAIN OUTCOME MEASURES: The percentage of mature follicles ovulating (ovulatory efficiency) was determined after in vivo and in vitro treatment. Fertilization, morula, and blastocyst development were evaluated every 24 hours for 120 hours. RESULTS: RU486 significantly inhibited ovulation, fertilization, and early embryonic development. CONCLUSIONS: Progesterone plays a significant role in ovulation, fertilization, and preimplantation embryonic development.

Animals↗
PubMed2002

Expression of Trps1 during mouse embryonic development.

The Trps1 gene codes for an atypical member of the GATA type family of transcription factors. Mutations in human TRPS1 lead to the tricho-rhino-phalangeal syndrome types I and III, which are characterized by craniofacial and skeletal abnormalities and disturbed hair development. Correspondingly, during mouse embryonic development strong Trps1 expression is found in the cartilage condensations, the developing joints, the hair follicles and in the developing snout. In addition, Trps1 is expressed surrounding the skeletal condensations, in the trachea, the intervertebral disks, and in lung and gut mesenchyme. A complex pattern of expression is also found in the developing brain.

Animals↗
PubMed2000

Retinoids in embryonal development.

The key role of vitamin A in embryonal development is reviewed. Special emphasis is given to the physiological action of retinoids, as evident from the retinoid ligand knockout models. Retinoid metabolism in embryonic tissues and teratogenic consequences of retinoid administration at high doses are presented. Physiological and pharmacological actions of retinoids are outlined and explained on the basis of their interactions as ligands of the nuclear retinoid receptors. Immediate target genes and the retinoid response elements of their promoters are summarized. The fundamental role of homeobox genes in embryonal development and the actions of retinoids on their expression are discussed. The similarity of the effects of retinoid ligand knockouts to effects of compound retinoid receptor knockouts on embryogenesis is presented. Although much remains to be clarified, the emerging landscape offers exciting views for future research.

Abnormalities, Drug-Induced↗
PubMed1985

Effect of acyclovir on mammalian embryonic development in culture.

Acyclovir [9-(2-hydroxyethoxymethyl)guanine] interfered with embryonic development in vitro when assessed with the "whole-embryo" culture technique. The "no-observed-effect level" was at 10 microM acyclovir; Minor impairment of embryonic development (retarded development of ear anlagen) was observed in vitro at 25 microM acyclovir in the culture medium. At high concentrations (100 or 200 microM) development of the ear anlagen was largely inhibited. At concentrations of 50 microM acyclovir or higher, additional disturbances of embryonic differentiation in vitro became obvious, resulting in gross structural abnormalities, especially of the brain (telencephalon); Histological examinations confirmed and extended these observations: at 100 microM acyclovir alterations of the neuroepithelium of the ventricles were pronounced, the telencephalon had developed poorly or was almost completely absent, and necroses were seen in the ear anlagen, the maxillary branch and within the somites; In a limb bud culture (mouse embryos, starting with day 11 of gestation) acyclovir interfered with the differentiation of cartilaginous bone anlagen at concentrations of 200 microM and more in the culture medium. A concentration of 100 microM induced no significant effect. Thus, this organ culture system is less sensitive to the action of acyclovir when compared with whole-embryo culture; Contrary to the results achieved with acyclovir, physiological nucleosides (2'-deoxyguanosine and 2'-deoxyadenosine) did not interfere with embryonic development in vitro even at the highest concentration tested (500 microM).

Abnormalities, Drug-Induced↗
PubMed2003

Changes in the content of progesterone receptor isoforms and estrogen receptor alpha in the chick brain during embryonic development.

Progesterone and estradiol participate in the regulation of several reproductive functions through interaction with intracellular progesterone receptors (PR) and estrogen receptors (ER), respectively. In this work, we determined PR and ER-alpha isoforms content in the brain of chicks of both sexes on days 8 and 13 of embryonic development as well as on the day of hatching by Western blot analysis. PR isoforms protein content increased during embryonic development in both female and male chick brain. The highest PR isoforms content was observed on the day of hatching in both sexes. Interestingly, PR-A content was higher in the brain of chick males than in that of females on day 8 of embryonic development. PR-A/PR-B ratio was higher in the brain of males than in that of females at all ages. We found two ER-alpha isoforms of 66 and 52 kDa; the content of both isoforms was higher in the brain of females than in that of males on days 8 and 13 of embryonic development. An opposite pattern of ER-alpha isoforms content was observed. In males, ER-alpha content increased during embryonic development whereas in the females it decreased during this process. These results indicate that the content of PR and ER-alpha isoforms is related to the degree of brain development in chicks, and suggest that PR and ER-alpha isoforms should exhibit sexual dimorphism in the brain of chicks during embryonic development.

Animals↗