• Plant Biotechnology Reports
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• v.3 no.4
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• pp.347-353
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• 2009

Procedures that induce microspore embryogenesis have been described for a range of Brassica species, but embryo yield remains low for a number of genotypes. We have carried out experiments with the microspores from a weakly responsive line of B. napus to determine the culture conditions that optimize their in vitro embryogenesis by treating them with effectors of ethylene synthesis and action. The results revealed that isolated microspores subjected to an initial heat stress in a medium supplemented with inhibitors of ethylene synthesis such as AVG and $CoCl_2$ exhibited significantly increased embryo yields. This suggested that regulatory effects are exerted by the ethylene produced by the isolated microspores on the early processes of gametogenesis. As a consequence, treatment of microspores with SAM, an ethylene synthesis precursor, or with the ethylene-releasing agent ethephon, led to decreases in embryo yield. A special response to ethylene during the early stages of microspore development was finally shown to occur through experiments where isolated microspores were treated for increasing periods of time with $CoCl_2$. Collectively, our data demonstrated that the induction of embryogenesis induced by heat stress can be enhanced by inhibitors of ethylene biosynthesis.

• Journal of Embryo Transfer
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• v.27 no.4
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• pp.211-221
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• 2012

The process of embryo implantation requires physical contact and physiological communication between the conceptus trophectoderm and the maternal uterine endometrium. During the peri-implantation period in pigs, the conceptus undergoes significant morphological changes and secretes estrogens, the signal for maternal recognition of pregnancy. Estrogens secreted from the conceptus act on uterine epithelia to redirect $PGF_2{\alpha}$, luteolysin, secretion from the uterine vasculature to the uterine lumen to prevent luteolysis as well as to induce expression of endometrial genes that support implantation and conceptus development. In addition, conceptuses secrete cytokines, interferons, growth factors, and proteases, and in response to these signals, the uterine endometrium produces hormones, protease inhibitors, growth factors, transport proteins, adhesion molecules, lipid molecules, and calcium regulatory molecules. Coordinated interactions of these factors derived from the conceptus and the uterus play important roles in the process of implantation in pigs. To better understand mechanism of implantation process in pigs, this review provides information on signaling molecules at the conceptus-uterine interface during early pregnancy, including recently reported data reported.

• The Korean Journal of Zoology
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• v.23 no.4
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• pp.263-272
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• 1980

Polyacrylamide gel electrophoresis was used to investigate the patterns of LDH and MDH isozymes in the embryo and adult of amphibia; Rana nigromaculata, Rana plancyi chosenica and Hynobius leechii. Rana nigromaculata is considered to be heterozygous for the gene specifying the "B" subunit of LDH, and Hynobius leechii to be heterozygous for the gene specifying the "A" subunit of LDH. The LDH isozyme paatern of embryos of the above three species is characterized by a gradual increase in the activity of LDH-5 (muscular form)during development. Two or three molecular forms of MDH is present steadily from early embryos and in adult. Of the MDH isozymes, the more cathodic one (MDH-m) appears weakly in early developing stages, but increases slowly in the activity as the embryo develops.the embryo develops.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.8
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• pp.3541-3546
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• 2011

Autophagy is an evolutionarily conserved lysosomal pathway for degrading cytoplasmic proteins, macromolecules, and organelles in addition to recycling protein and ATP synthesis. Although autophagy is very important during embryogenesis, the mechanism underlying the dynamic development during this process remains largely unknown. In order to obtain insights into autophagy in early embryo development, we analyzed gene expression levels of autophagy-related genes (ATGs) in mouse embryos developing in vitro. Using real time RT-PCR technique, ATGs including Atg2a, Atg3, Atg4b, Atg5, Atg6, Atg7, Atg9a, and Wipi3, as maternal transcripts, were only up-regulated in 1-cell embryo stage before zygotic genomic activation (ZGA), and then expression decreased from 2-cell to blastocyst embryo stage. ATGs including Dram and Atg9b were expressed abundantly in 1-cell embryo state and in blastocyst embryo stage, athough Atg8 and Ulk1 were constantly expressed during preimplantation stage. However, Atg4d were only up-expressed from 4-cell to blastocyst stage. These results suggest that autophagy is related in mouse embryo, which possibly gives an important role for early development.

• Journal of Aquaculture
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• v.20 no.3
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• pp.194-198
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• 2007

Reproductive traits of Palaemon gravieri such as embryo size, number of embryo (fecundity), incubation period, larval development mode, larval development period, larval survival and larval growth were described and compared to analyze the correlation among those traits. Embryo volume is a primary factor determining other ensuing reproductive features. Egg volume was $0.042mm^3$ in the first developmental stage. Embryo volume in P. gravieri was comparatively small which is indicative of great number of embryo (y = 3.0161x + 0.0185 $R^2$ = 0.74 positive isometric relationship) and relatively long incubation period. Larvae survived from zoea 1 to post-larvae and it took 45 days at $22^{\circ}C$. Survival rate of the larvae was rather great in the early stage and thereafter steadily decreased. Daily growth rate of larvae in P. gravieri at $22^{\circ}C$ was 0.0195 mm on average. They grew steadily as time went by. Incubation period was between 10-14 days at $22^{\circ}C$. Larval development mode was almost complete planktotrophic. PNR (point of no return) appeared to be the third day on average. Survival rate of larvae without feeding declined rapidly between 3 and 4 days. Larval development period and stage frequency were 23-30 days and 11 stages which imply prolonged larval period and high mortality. The pattern of brood production followed fast successive parturial pattern. Most ovigerous female had mature ovary when they performed parturial molt soon after hatching (larval release).

• Asian-Australasian Journal of Animal Sciences
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• v.8 no.6
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• pp.557-562
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• 1995

In this study, characteristics of chick primordial germ cells (PGCs), which is the founder cell of the germline, and gonadal development of the chick embryo between 12hrs and 6 day of incubation were investigated by transverse serial sections of chick embryos under the light microscopic observation. In embryo stage 20 (3 day of incubation), there are a lot of PGCs at the mesenchym, which were moving to the thickened epithelium (gonadal ridge). The PGCs arrive at both right and left gonad primordial in equal number prior to stage 24 (4 day of incubation), but in the following stages, the distribution of the PGCs became asymmetrical. More PGCs colonized the left than the right gonad, but the reason for the unequal distribution of PGCs is uncertain. The PGCs have mostly settled in the gonadal ridge (GR) at 6 day embryo. This study was conducted to investigate characteristics of the PGC migration and gonadal formation and observe the best condition for PGC isolation, culture and to attempt the possibility of the production for transgenic germline chimeras with manipulated PGCs.

• Proceedings of the KSAR Conference
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• 2004.06a
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• pp.229-229
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• 2004

The identification of embryo-specific genes would provide insights into early embryonic development. However, the current methods employed to identify the genes that are expressed at a specific developmental stage are labor intensive and suffer from high rates of false positives. Here we employed a new and accurate reverse transcription-polymerase chain reaction (RT-PCR) technology that involves annealing control primers (ACPs) to identify the genes that are specifically or prominently expressed in bovine early blastocysts and hatched blastocysts produced in vitro. (omitted)

• Journal of Korean Society on Water Environment
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• v.28 no.5
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• pp.762-767
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• 2012

The ecotoxicity assessment of nanomaterials (NMs) in the environment is actively conducted throughout the world because of the concerns about their potential risk from usage and release into the environment, as well as their unique physiochemical properties. Ecotoxicity tests for NMs have been conducted using various species and methods; however, in spite of these efforts, the characteristics and toxicity of NMs have not been defined. The fish embryo toxicity test (FET) has been conducted extensively to evaluate the toxicity of NMs as an alternative to a whole-body test in fish. In this study, we collected and analyzed the trends of nanotoxicity on the early development of freshwater fish. The model nanomaterials are carbon NMs ($C_{60},\;C_{70},\;C_{60}$(OH)n and carbon nanotube). Their adverse effects were extensively investigated based on the properties of NMs, test species, and diverse exposure conditions.

• Reproductive and Developmental Biology
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• v.29 no.3
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• pp.145-147
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• 2005

Autocrine or paracrine mediators released by the early embryo are implicated in the support of embryonic development. Their mechanisms and optimal embryo density in the medium, however, are uncertain. This study was conducted to establish the optimal embryo density and culture medium volume in mouse parthenogenetic embryo culture. In experiment 1, culture of parthenogenetirally activated oocytes at a concentration of $2{\~}4$ embryos/${\mu}L$ significantly improved development to the blastoryst stage ($72{\%}{\leq}$) compared with culture at the lower ($0.2{\~}1$e mbryos/${\mu}L,\;0\~37.5\%$) and the higher ($5{\~}6$ embryos/${\mu}L,\;30\~53\%$) concentration for 120 h when the oocytes were cultured in a 5 ${\mu}L$ drop under mineral oil In experiment 2, the embryos cultured at a concentration of $2{\~}4$ embryos/${\mu}L$ in a 10 ${\mu}L$ drop ($81.1{\%}$) showed significantly higher blastocyst rates than those in a 5 ${\mu}L$ drop ($68.5{\%}$). This study optimizes in vitro culture condition by modifying embryo density and the volume of culture medium It may give appropriate level of autocrine and/or paracrine factors to enhance viability and subsequent normal development of mouse parthenogenetic embryos in vitro.

• Journal of Embryo Transfer
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• v.29 no.3
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• pp.257-264
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• 2014

Recently, several approaches have been used to measure the oxygen consumption rates of individual embryos, but relationship between oxygen consumption and pregnancy rates of Hanwoo following embryo transfer has not yet been reported. In this study, we investigated the correlation between oxygen consumption rate and pregnancy rates of Hanwoo embryo using a SECM. In addition to, the expression of apoptosis-related genes was determined using real-time PCR by extracting RNA according to the oxygen consumption of in vivo embryo. First, we found that the oxygen consumption significantly increased in blastocyst-stage embryos (blastocyst) compared to early blastocyst stage embryos, indicating that oxygen consumption reflects the embryo quality (Grade I). The oxygen consumption or GI blastocysts were significantly higher than those of GII blastocysts ($10.2{\times}10^{14}/mol\;s^{-1}$ versus $6.4{\times}10^{14}/mol\;s^{-1}$, p<0.05). Pregnant rate in recipient cow was 0, 60 and 80% in the transplantation of embryo with the oxygen consumption of below 10.0, 10.0~12.0 and over $12.0{\times}10^{14}/mol\;s^{-1}$, respectively. Apoptosis regulatory genes, Hsp-70.1 were significantly increased in over-10.0 group than below 10.0 group but in Caspase-3, Bax and P53 gene, there was no significant difference. In conclusion, These results suggest that measurement of oxygen consumption maybe help increase the pregnant rate of Hanwoo embryos.