• Journal of Animal Science and Technology
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• v.51 no.6
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• pp.485-492
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• 2009

Estrogen has dramatic effects on the development and function of the reproductive tract in mammals. Although diethylstilbestrol (DES) triggers the development of reproductive organs in immature animals, continued exposure to DES induces dysfunction of the female reproductive tract in mice. To investigate the effects of neonatal estrogen exposure on the reproductive tract of female chickens, we implanted DES pellets into the abdominal region of immature female chicks and then examined the effects of DES on the oviducts of both immature chicks and sexually mature chickens (30 weeks old). DES induced mass growth and differentiation of the oviduct in immature chicks. The chick oviduct increased by 2.7- and 29-fold in length and weight, respectively, following primary DES stimulation. In secondary DES stimulation, the length and weight of the chick oviduct increased by 4.5- and 74-fold, respectively. Additionally, DES treatments caused abnormal development of the infundibulum and magnum in hen oviducts. Furthermore, infundibulum abnormality gave rise to unusual ovulation of follicles and resulted in infertility and dysfunction of the magnum, such as less production of egg white proteins. Our results indicate that DES exposure during early developmental stages in chickens has detrimental effects on the development and maintenance of the female reproductive tract after sexual maturation.

• Applied Microscopy
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• v.28 no.1
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• pp.91-105
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• 1998

The present study is undertaken to investigate the hypertrophical changes of the corpus allatum (corpora allata, CA) after the ovariectomy in Blattella germanica. In particular, the ultrastructural aspects of the normal and ovariectomized conditions, and induced factors of the hypertrophic phenomenon are focused. Ultrastructure of the CA from an immediately emergent adult is similar to that of the last larval stage that has stopped secreting juvenile hormone. The CA is composed of undifferentiated cells, exhibiting an electron-lucent matrix, a few mitochondria and less smooth endoplasmic reticulum. The karyoplasm occupy most of the cytoplasm. Electron-dense materials are filled with the intercellular spaces and gap junctions are also found. Almost no ultrastructural changes have been noticed during seven days until the oviposition. However, considerable changes in structure have been detected soon after the oviposition. Mitochondria are increased dramatically in number and cristae, and changed to the filamentous form with a high electron density. In addition, Golgi complexes, microtubules, and polysomes are also increased. After an oviposition, the total volume of the CA are decreased again. The volume of the CA are increased continuously, hypertrophy, after the ovariectomy. Morphological aspects of the CA in an early stage after the removal are similar to the structure of the secondary egg maturation. Large and electron dense globules are observed in the ovariectomized CA cytoplasms and they are present in those cells for a long period of time. Yet such a hypertrophical phenomenon occur only in the specific cells. The hypertrophy are caused by hollowing the part of the CA cells and later filling such site with polysomes. In 42 days after the ovariectomy, the nuclear membranes disappear in the CA cells, thus, exhibiting the prokaryotic-like features. Some results of the current study will contribute to the establishment of the model that explain unusual changes accompanied by certain treatment in insects and/or further in animals.

• Molecules and Cells
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• v.43 no.6
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• pp.581-589
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• 2020

Neurons have multiple dendrites and single axon. This neuronal polarity is gradually established during early processes of neuronal differentiation: generation of multiple neurites (stages 1-2); differentiation (stage 3) and maturation (stages 4-5) of an axon and dendrites. In this study, we demonstrated that the neuron-specific n-glycosylated protein NELL2 is important for neuronal polarization and axon growth using cultured rat embryonic hippocampal neurons. Endogenous NELL2 expression was gradually increased in parallel with the progression of developmental stages of hippocampal neurons, and overexpression of NELL2 stimulated neuronal polarization and axon growth. In line with these results, knockdown of NELL2 expression resulted in deterioration of neuronal development, including inhibition of neuronal development progression, decreased axon growth and increased axon branching. Inhibitor against extracellular signal-regulated kinase (ERK) dramatically inhibited NELL2-induced progression of neuronal development and axon growth. These results suggest that NELL2 is an important regulator for the morphological development for neuronal polarization and axon growth.

• The Korean Journal of Zoology
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• v.31 no.2
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• pp.81-86
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• 1988

The relationship between cumulus cell expansion, cocyte maturation and metabolic cooperativitiy was investigated by using mouse and pig cocyte-cumulus complexes in vitro. Cocyte germinal vesicle breakdown (GVBD) and cumulus expansion were manipulated with hormones or reagents which increase intracellular cAMP leveL Metabolic cooperativity between oocyte and cumulus cells was assessed by determination of the fraction of radiolabelled uridine marker that was transferred from the cumulus mass to the oocyte. Uptake of uddine marker by mouse and pig cumulus mass was increased by about fourfold of basal level with the stimulation of hormones (human choriononic gonadotrophin, HCG; follicle stimulating hormone, FSH) or cyclic AMP sttmulators (3-isobutyl-1-methylxanthine, IBMX; forskolin) during culture. However, the fraction of uridine that was transferred from the cumulus mass to the cocyte (transfer ratio) was gradually decreased during culture, irrespective with the presence of hormones or stimulators. The decrease of the transfer ratio was not correlated with the state of occyte whether they have GV or not, or with the degree of cumulus expansion. In mouse complexes, HCG induced more significant reducton of transfer ratio than other treatments. These results do not support the idea that modulations of metabolic cooperativity between cumulus cells and oocytes are important for the regulation of meiotic resumption in mammals.

• Korean Journal of Plant Resources
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• v.16 no.3
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• pp.238-244
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• 2003

During the life cycle, plants have to suffer from various environmental stresses. A common element in response to many environmental stresses is cellular dehydration. Dehydrins are a family of proteins commonly induced by environmental stresses associated with low temperature or dehydration and during seed maturation drying. For the study in the defense mechanism against various stresses, a cDNA clone encoding a dehydrin gene was isolated from a cDNA library prepared from tab root mRNAs of Codonopsis lanceolata. The cDNA, designated ClDhn1, is 893 nucleotides long and has an open reading frame of 480 bp with a deduced amino acid sequence of 159 residues. The ClDhn1 amino acid sequence is highly hydrophilic and possesses two conserved repeats of characterized lysine­rich K­segment (KIKEKLPG), and a 7­serine residue stretch prior to the first lysine­rich repeat that is common to many dehydrins. The DEYGNP conserved motif is, however, modified in the sequence of ClDhn1 gene. The deduced amino acid sequence of ClDhn1 was compared with other plant dehydrinls and showed high homology with Solanum commersonii

• Korean Journal of Plant Resources
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• v.11 no.1
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• pp.9-14
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• 1998

Two types of somatic embryos were directly induced from the immature zygotic embryos of the wild prunus yedoensis in Mt. Halla after 16 weeks of culture on MS medium supplemented with 0.1mg/L $GA_3$ and 0.1mg/L BAPor 0.5mg/L $GA_3$ and 0.1mg/L BAP. One was normal single embryo with a single basal part. Normal somatic embryos germinated successfully on 1/2 MS medium. However, abnormal nulticotyledonary somatic embryos, formed shoots only on hormone free MS medium and about 80% of shoots rooted on MS medium with 0.5mg/L IBA. The mximum frequency (62.5%) of normal somatic embryos was directly obtained from the zygotic embryo 30 days after full blooming but it was decreased with further maturation.

• Molecules and Cells
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• v.40 no.8
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• pp.550-557
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• 2017

The periodontal ligament (PDL) is the connective tissue between tooth root and alveolar bone containing mesenchymal stem cells (MSC). It has been suggested that human periodontal ligament stem cells (hPDLSCs) differentiate into osteo/cementoblast and ligament progenitor cells. The periodontitis is a representative oral disease where the PDL tissue is collapsed, and regeneration of this tissue is important in periodontitis therapy. Fibroblast growth factor-2 (FGF-2) stimulates proliferation and differentiation of fibroblastic MSCs into various cell lineages. We evaluated the dose efficacy of FGF-2 for cytodifferentiation of hPDLSCs into ligament progenitor. The fibrous morphology was highly stimulated even at low FGF-2 concentrations, and the expression of teno/ligamentogenic markers, scleraxis and tenomodulin in hPDLSCs increased in a dose dependent manner of FGF-2. In contrast, expression of the osteo/cementogenic markers decreased, suggesting that FGF-2 might induce and maintain the ligamentogenic potential of hPDLSCs. Although the stimulation of tenocytic maturation by $TGF-{\beta}1$ was diminished by FGF-2, the inhibition of the expression of early ligamentogenic marker by $TGF-{\beta}1$ was redeemed by FGF-2 treatment. The stimulating effect of BMPs on osteo/cementogenesis was apparently suppressed by FGF-2. These results indicate that FGF-2 predominantly differentiates the hPDLSCs into teno/ligamentogenesis, and has an antagonistic effect on the hard tissue differentiation induced by BMP-2 and BMP-4.

• The Korean Journal of Physiology and Pharmacology
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• v.20 no.5
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• pp.533-538
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• 2016

Angiogenesis plays an essential role in embryo development, tissue repair, inflammatory diseases, and tumor growth. In the present study, we showed that endothelial nitric oxide synthase (eNOS) regulates retinal angiogenesis. Mice that lack eNOS showed growth retardation, and retinal vessel development was significantly delayed. In addition, the number of tip cells and filopodia length were significantly reduced in mice lacking eNOS. Retinal endothelial cell proliferation was significantly blocked in mice lacking eNOS, and EMG-2-induced endothelial cell sprouting was significantly reduced in aortic vessels isolated from eNOS-deficient mice. Finally, pericyte recruitment to endothelial cells and vascular smooth muscle cell coverage to blood vessels were attenuated in mice lacking eNOS. Taken together, we suggest that the endothelial cell function and blood vessel maturation are regulated by eNOS during retinal angiogenesis.

• Journal of Nutrition and Health
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• v.30 no.5
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• pp.478-488
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• 1997

Omega-3 fatty acid, docosahexaenoic acid(DHA) is found in a high proportion in the structural lipids of cell membranes, in particular those of the central nervous system and the retina. Diet-induced changes in fatty acid composition in these tissues may affect physiochemical functions. This study was conducted to investigate whether supplements of DHA in infant formula has an effect on the composition of fatty acids in erythrocytes with regard to brain development. Experimental groups were breastmilk group(n=21), placebo formula group(n=15), and DHA supplemented formula (0.26%) group(n=16). Infants were selected by mothers who deliverecdd at Kyung Hee medical center from February to April, 1996. Infant body weight, length, and head circumference were similar among the experimental groups at 16 weeks of age. The levels of DHA in breastmilk, placebo formula, and DHA supplemented formula were 0.56, 0, and 0.26% of total fatty acids, respectively. There was a significant correlation between dietary DHA intake and erythrocyte DHA levels. The levels of arachidonic acid did not differ among the three expermental groups. The result of flash visual evoke potential(VEP) test was correlated with the erythrocyte levels and dietary DHA levels at 16 weeks of age. No other fatty acid was correlated with VEP test results. No differences were found in Bayley Mental and Psychomotor Development Index scores among the three groups at 20 weeks of age. DHA seems to be an essential nutrient for optimum growth and maturation of term infants. Relatively small amounts of dietary DHA supplementation significantly elevate DHA supplementation significantly elevate DHA content in erythrocytes, which in turn has an implication for better scores for infant's VEP test. Whether supplementation of formula-fed infants with DHA has long-term benefits remains to be elucidated.

• The Korean Journal of Zoology
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• v.27 no.1
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• pp.1-12
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• 1984

In order to investigate the alkaline phosphtase activities in the mouse oocytes in matuation and preimplantation embryos in developing in culture, the enzyme activities were measured by means of biochemical method. The in vitro effect of levamisole which is known as an inhibitor of the lakaline phosphatase was also observed on the oocyte in maturation and the embryos in early embryogenesis. The results obtained were as follows: The enzyme activity was not detected in the embryos unitl the stage of 4-cell, but it appeared first in the 4-cell embryos and the level of the activity was steady through up to the blastocyst. Levamisole inhibited the alkaline phosphatase activity in the blastocyst, and the activity decreased by almost 70% at 10 mM and 50% at 1 mM as compared with the control. In addition, levamisole inhibited completely the formation of polar body by the oocytes. and induced degeneration of the preimplantation embryos at the dose of 0.5 mM or higher.