• Journal of Applied Biological Chemistry
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• v.65 no.4
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• pp.239-245
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• 2022

Although normal activation of platelets is important in the process of hemostasis, excessive or abnormal activation of platelets can lead to cardiovascular diseases. Therefore, the discovery of novel substances capable of regulating or inhibiting platelet activation may be helpful in the prevention and treatment of cardiovascular diseases. Artemether is a derivative of artemisinin, known as an active ingredient of Artemisia annua, which has been reported to be effective in treating malaria, and is known to function through antioxidant and metabolic enzyme inhibition. However, the role of artemether in platelet activation and aggregation and the mechanism of action of artemether in collagen-induced human platelets are not known until now. This study investigated the effects of artemether on platelet activation and thrombus formation induced by collagen. As a result, cAMP level was significantly increased by artemether, and VASP and IP3R, substrates of cAMP-dependent kinase, were phosphorylated. IP3R phosphorylation by Artemether inhibited Ca²⁺ recruitment into the cytoplasm, and phosphorylated VASP inhibited fibrinogen binding by inactivating αIIb/β3 located on the platelet membrane. Consequently, artemether inhibited thrombin-induced fibrin clot formation. Therefore, we propose that artemether can act as an effective prophylactic and therapeutic agent for cardiovascular diseases caused by excessive platelet activation and thrombus formation.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2002.11a
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• pp.78-78
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• 2002

The role of heat shock proteins in shielding organism from environmental stress is illustrated by the large-scale synthesis of these protein by the organism studied to date. However, recent evidence also suggests an important role for heat shock protein in fertilization and early development of mammalian embryos. Effects of elevated in vitro temperature on in vitro produced bovine embryos were analysed in order to determine its impact on the expression of heat shock protein 70 (HSP70) by control and frozen-thawed after in vitro fertilization (IVF) or nuclear transfer (NT). The objective of this study was to assess the developmental potential in vitro produced embryos with using of the various containers and examined expression and localization of heat shock protein 70 after it's frozen -thawed. For the vitrification, in vitro produced embryos at 2 cell, 8 cell and blastocysts stage after IVF and NT were exposed the ethylene glycol 5.5 M freezing solution (EG 5.5) for 30 sec, loaded on each containers such EM grid, straw and cryo-loop and then immediately plunged into liquid nitrogen. Thawed embryos were serially diluted in sucrose solution, each for 1 min, and cultured in CRI-aa medium. Survival rates of the vitrification production were assessed by re-expanded, hatched blastocysts. There were no differences in the survival rates of IVF using EM grid, cryo-loop. However, survival rates by straw were relatively lower than other containers. Only, nuclear transferred embryos survived by using cryo-loop. After IVF or NT, in vitro matured bovine embryos 2 cell, 8 cell and blastocysts subjected to control and thawed conditions were analysed by semiquantitive reverse transcription polymerase chain reaction methods for hsp 70 mRNA expression. Results revealed the expression of hsp 70 mRNA were higher thawed embryos than control embryos. Immunocytochemistry used to localization the hsp70 protein in embryos. Two, 8-cell embryos derived under control condition was evenly distributed in the cytoplasm but appeared as aggregates in some embryos exposed frozen-thawed. However, under control condition, blastocysts displayed aggregate signal while Hsp70 in frozen-thawed blastocysts appeared to be more uniform in distribution.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.4
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• pp.431-435
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• 1985

Nine hybrid rices crossed between Korean cytoplasmic-genetic male sterile rices having the WA cytoplasm and the Korean restorer lines or varieties, HR1619A/Nampungbyeo, HR1619A/Gayabyeo, HR1619A/Line234, TongilA/Nampungbyeo, TongilA/Cheongcheongbyeo, Suwon 296A/Line 209, Suwon 296A/Line 237, Suwon 296A/Line 252 and Line 201A/Line 234, and their parents were grown at Yeungnam University in 1984. The rough rice yield of the hybrids Line 201A/Line 234, TongilA/Nampungbyeo and HR1619A/Nampungbyeo were 939, 927 and 900 Kg/10a respectively. The heterosis(F$_1$/Midparent) of the above three hybrids was 40%, 20% and 19%, the heterobeltiosis(F$_1$/Better parent) was 36%, 17% and 10%, and the standard heterosis (F$_1$/Standard variety, Cheongcheongbyeo) was 19%, 17% and 14% respectively. The hybrids HR1619A/ Gayabyeo and Suwon 296A/Line 237 showed negative heterosis in grain yield. Significant heterobeltiosis for grain number per panicle was found while less or no heterobeltiosis was observed in panicle number per hill, 1000-grain weight and grain fertility. The bacterial leaf blight disease reaction of the hybrids tested was almost the same as that of one parent at least. The amylose content of the hybrids was medium to low the same as their parents. The protein content and alkali digestion value of the hybrids were almost the same as their parents.

• Journal of Embryo Transfer
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• v.16 no.3
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• pp.223-231
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• 2001

The success of nuclear transplantation with mammalian oocytes depends critically on the potential of oocytes activation, which mainly caused to prevent the re-accumulation of maturation promoting factor (MPF). This study was conducted to compare the effect of combined treatment of lonomycin with a Hl-histone kinase inhibitor (dimethylaminopurine, DMAP) or cdc2 kinase inhibitor (sodium pyrophosphate, SPP) on activation of bovine oocytes. In vitro matured bovine oocytes with the first polar body (PB) and dense cytoplasm were assigned to 3 experimental groups. For activation treatment, oocytcs were exposed to 5 $\mu$M lonomycin for 5 min (Group 1), and followed by 1.9 mM dimethylaminopurine (DMAP) for 3 h (Group 2) or followed by 2 mM sodium pyrophosphate (SPP) for 3 h (Group 3). The activation effects in the three treatments and the control group (untreated) were judged by the extrusion of the second PB and formation of a pronucleus (PN). Differences among groups were analysed using one-way ANOVA after arc-sine transformation of proportional data. All three treatments led to high activation rates (90% to 95%), with significant difference from the control. However, the extrusion of the second PB and the rate of PN formation differed remarkably among treatments. In Group I and 3, about 95% of the oocytes had extruded the second polar body, but one PN had formed in a higher proportion of oocytes in Group 3 than in Group 1 (90% vs. 5%). In experiment 2, the rates of cleavage and development into blastocysts in Group 1 were significantly lower than those of Group 2 and 3 (8.7% and 0% vs. 50.5% and 11.6%, and 44.6% and 7.2%, respectively, P<0.05). In experiment 3, ~80% of parthenotes in Group 1 were developed with haploid chromosomal sets. However, when ionomycin was followed immediately by DMAP (Group 2). only 20% of parthenotes were haploid. In Group 3, combined treatment with ionomycin and SPP, the appearance of abnormal chromosomal tracts was significantly (P〈0.05) reduced and the proportion of haploid parthenotes was increased to 85% (17/20) than in Group 2. These results demonstrate that SPP acted as a cdc2 kinase inhibitor and formed the haploidy in oocyte activation. Thus, the present study suggests that cdc2 kinase inhibitor, such as sodium pyrophosphate, may have an effective role in oocyte activation for the production of cloned embryos/animals by nuclear transplantation.

• The Korean Journal of Zoology
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• v.15 no.3
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• pp.111-131
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• 1972

Fine structures of retina of an ommatidium in dragonfly, having eyes of closed rhabdom type, were studied under light and electron microscopes. The ommatidia consisted of eight retinular cells distributed in a circular pattern and the retinular layer in turn can be divided into three sublayers according to the number of cells in the retina. Each retinular cell has different starting points in the retina and the length of retinular cells is varied greatly; the length of one distal retinular cell shows one half of that of others. In the middle layer, three proximal retinular cells interconnect the adjacent two rhabdoms which are triangular in the appearence of the cross section which in turn consisted of tubular, parallel and lamellated microvilli. The rhabdom is formed by three rhabdomeres, each of which is separated by $120^{\circ}$ between them, but they can be distinguished into two parts according to electron density. Around the outer part of microvilli composing rhabdom, electron density was much less than the inner part of the structure. The microvilli of the inner part appear to be connected to the cytoplasm of retinular cells. Rough endoplsmic reticulum with enlarged cisternae runs through the vacuoles in the outer part of distal retinular cells. Abundant mitochondria concentrated in the vicinity of rhabdom are found at the central part of the retinular cells, while in the area of immediate vicinity of the rhabdom, prominent vacuoles are observed. Above the rhabdom of an ommtidium stands a crystalline cone which is consisted of four cone cells arranged radially along the axis. The crystalline cone is surrounded by cells containing pigment granules. The outermost photoreceptor element of an ommatidium is corneal lens.

• The Korean Journal of Zoology
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• v.22 no.3
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• pp.103-114
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• 1979

The authors observed the ultrastructure of the granular glands in the amphibian skin with an electron microscope. The specimens from the experimental animals (Bombina orientalis, Bufo bufo gargarizans, Rana nigromaculata and Rana rugosa) were fixed in 2.5% glutaraldehyde-paraformaldehyde fixative in phosphate buffer at pH 7.2 prior to fixation in 1% osmium tetroxide, dehydrated in graded ethanol and acetone, embedded in Epon 812 mixture, and sectioned with a LKB-ultramicrotome. the ultrathin sections were contrasted with uranyl acetate and lead citrate and observed with a JEOL-100B electron microscope. The results were as follws: 1. The granular gland in the amphibian skin consisted of the glandular epithelial and the myoepithelial cells. 2. The epithelial cells of the granular gland in the amphibian skin consisted of the dark cells but the light cells were also observed in that of Bombina orientalis. 3. The granular glands of the amphibian skin were in holocrine fashion. 4. The nuclei of the epithelial cells of the amphibian cutaneous granular glands were round or oval and showed small and large inforldings of nuclear envelope. Heterochromatins were mainly distributed near the nuclear envelope. Mitochondria were mainly distributed in the perinuclear portion and rough-surfaced endoplasmic reticulums were developed in the cytoplasm but smooth-surfaced endoplasmic reticulums were not well developed. 5. Secretory granules were round or oval and electron-dense and less electron-dense granules were observed. 6. The authors infer that the differences in electron density of the secretory granules in the granular glands of the amphibian skin are due to difference in the concentrations of secretory substances as related to the processes of its formation, and that those chemical components are identical.

• The Korean Journal of Zoology
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• v.28 no.1
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• pp.44-59
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• 1985

The epithelium of the hindgut in the german cockroach, Blattella germanica Linne, was observed with electron microscope. The epithelium of the ileum, which is located at the anterior hindgut, is composed of a single layer of squamous and cuboidal cells. The liminal surface of the epithelium is lined with the cuticular intima. The epithelial cells contain cell organelles expected to be found in absorptive cells, and some epithelial cells have numerous lamelated crystals, the "spherites". The rectal epithelium of posterior hindgut is composed of rectal pads which are covered with cuticular intima on the luminal side. The rectal pads are composed of columnar absorptive cells and basal cells. The apical plasma membrane of columnar cell is made of microvilli, where mitochondria associated with some of the microvilli. The lateral plasma membrane is highly infolded and space is an uniform width of approximately 200$\\AA$. Well developed mitochondria are found closely associated with the infoldings and this is referred to as the "mitochondrial-scalariform complex". A septate junction is found near the apical zone between the columnar absorptive cells, whereas many desmosomes and intercellular spaces are formed between the columnar cells. Basal cells are bowl-shaped where the convex surface is inlaid into the basal surface of the columnar cells while the concave surface faces the basal lamina. The cytoplasm of the basal cell is electron dense and contains well developed cell organelles. The basal sheath is located between the basal membrane and basal lamina, providing barrier between the epithelium and the hemolymph. The epithelium is surrounded by the subepithelial space and muscles. The subepithelial space, which is composed of fibrous connective tissue, is innervated by many tracheoles and axons.

• Animal Bioscience
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• v.35 no.10
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• pp.1616-1627
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• 2022

Objective: This work was conducted to investigate the effects of oxidative stress on meat quality, mitochondrial function, calcium metabolism and ferroptosis of broilers. Methods: In this study, a total of 144 one-day-old male Ross 308 chicks were divided into 3 groups (control group, saline group, and hydrogen peroxide [H₂O₂] group) with 6 replicates of 8 broilers each. The study lasted for 42 d. The broilers in the saline and H₂O₂ groups were intraperitoneally injected with 0.75% saline and 10.0% H₂O₂ on the 16th and 37th day of the experimental period respectively, the injection volumes were 1.0 mL/kg of broiler body weight. On the 42nd day of the experimental period, two chicks were randomly selected from each cage, a total of thirty-six chicks were stunned by electric shock and slaughtered to collect breast muscle samples. Results: The H₂O₂ exposure reduced pH value, increased drip loss and shear force of breast meat (p<0.05), impaired the ultrastructure and function of mitochondria. The H₂O₂ exposure damaged the antioxidant system in mitochondria, excessive reactive oxygen species carbonylation modified calcium channels on mitochondria, which impaired the activities of key enzymes on calcium channel, resulted in the increased calcium concentration in cytoplasm and mitochondria (p<0.05). In addition, the H₂O₂ exposure increased the iron content and lipid peroxidation (p<0.05), which induced ferroptosis. Conclusion: Oxidative stress could impair meat quality by causing mitochondrial dysfunction, resulting in calcium metabolism disorder and ferroptosis.

• Journal of Life Science
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• v.33 no.11
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• pp.956-965
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• 2023

In plants, there are many CCCH zinc finger proteins consisting of three cysteine residues and one histidine residue, which bind to zinc ions with finger configuration. CCCH-type zinc finger proteins are divided into tandem CCCH-type zinc finger (TZF) and non-TZF proteins: TZF proteins contain exactly two tandem CCCH-type zinc finger motifs whereas non-TZF proteins have fewer or greater than two CCCH-type zinc finger motifs. The functions of TZF genes, especially plant-specific RR-TZF genes, have been well studied in several plants, whereas the functional roles of non-TZF genes have not been adequately researched compared to TZF genes. Many non-TZF genes have been identified as being involved in the responses to biotic and abiotic stresses, such as pathogen, high salt, drought, cold, heat, and oxidative stresses. Some non-TZF proteins bind to RNA and are involved in the post-transcriptional regulation of stress-responsive genes in the cytoplasm. In addition, other non-TZF proteins act as transcriptional activators or repressors that regulate the expression of stress-responsive genes in the nucleus. Despite these studies, stress signal transduction and upstream and downstream genes of non-TZF genes have not been sufficiently researched, suggesting that additional studies of the functions of non-TZF genes' functions in plants' stress responses are needed. In this review, we describe non-TZF genes involved in biotic abiotic stress responses in plants and their molecular functions.

• Molecules and Cells
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• v.46 no.10
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• pp.592-610
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• 2023

The Hippo kinase cascade functions as a central hub that relays input from the "outside world" of the cell and translates it into specific cellular responses by regulating the activity of Yes-associated protein 1 (YAP1). How Hippo translates input from the extracellular signals into specific intracellular responses remains unclear. Here, we show that transforming growth factor β (TGFβ)-activated TAK1 activates LATS1/2, which then phosphorylates YAP1. Phosphorylated YAP1 (p-YAP1) associates with RUNX3, but not with TEAD4, to form a TGFβ-stimulated restriction (R)-point-associated complex which activates target chromatin loci in the nucleus. Soon after, p-YAP1 is exported to the cytoplasm. Attenuation of TGFβ signaling results in re-localization of unphosphorylated YAP1 to the nucleus, where it forms a YAP1/TEAD4/SMAD3/AP1/p300 complex. The TGFβ-stimulated spatiotemporal dynamics of YAP1 are abrogated in many cancer cells. These results identify a new pathway that integrates TGFβ signals and the Hippo pathway (TGFβ→TAK1→LATS1/2→YAP1 cascade) with a novel dynamic nuclear role for p-YAP1.