• Molecules and Cells
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• v.45 no.4
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• pp.169-176
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• 2022

A primary cilium, a hair-like protrusion of the plasma membrane, is a pivotal organelle for sensing external environmental signals and transducing intracellular signaling. An interesting linkage between cilia and obesity has been revealed by studies of the human genetic ciliopathies Bardet-Biedl syndrome and Alström syndrome, in which obesity is a principal manifestation. Mouse models of cell type-specific cilia dysgenesis have subsequently demonstrated that ciliary defects restricted to specific hypothalamic neurons are sufficient to induce obesity and hyperphagia. A potential mechanism underlying hypothalamic neuron cilia-related obesity is impaired ciliary localization of G protein-coupled receptors involved in the regulation of appetite and energy metabolism. A well-studied example of this is melanocortin 4 receptor (MC4R), mutations in which are the most common cause of human monogenic obesity. In the paraventricular hypothalamus neurons, a blockade of ciliary trafficking of MC4R as well as its downstream ciliary signaling leads to hyperphagia and weight gain. Another potential mechanism is reduced leptin signaling in hypothalamic neurons with defective cilia. Leptin receptors traffic to the periciliary area upon leptin stimulation. Moreover, defects in cilia formation hamper leptin signaling and actions in both developing and differentiated hypothalamic neurons. The list of obesity-linked ciliary proteins is expending and this supports a tight association between cilia and obesity. This article provides a brief review on the mechanism of how ciliary defects in hypothalamic neurons facilitate obesity.

• Mycobiology
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• v.51 no.5
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• pp.273-280
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• 2023

The nucleolus is the largest, membrane-less organelle within the nucleus of eukaryotic cell that plays a critical role in rRNA transcription and assembly of ribosomes. Recently, the nucleolus has been shown to be implicated in an array of processes including the formation of signal recognition particles and response to cellular stress. Such diverse functions of nucleolus are mediated by nucleolar proteins. In this study, we characterized a gene coding a putative protein containing a nucleolar localization sequence (NoLS) in the rice blast fungus, Magnaporthe oryzae. Phylogenetic and domain analysis suggested that the protein is orthologous to Rrp8 in Saccharomyces cerevisiae. MoRRP8-GFP (translational fusion of MoRRP8 with green fluorescence protein) co-localizes with a nucleolar marker protein, MoNOP1 fused to red fluorescence protein (RFP), indicating that MoRRP8 is a nucleolar protein. Deletion of the MoRRP8 gene caused a reduction in vegetative growth and impinged largely on asexual sporulation. Although the asexual spores of DMorrp8 were morphologically indistinguishable from those of wild-type, they showed delay in germination and reduction in appressorium formation. Our pathogenicity assay revealed that the MoRRP8 is required for full virulence and growth within host plants. Taken together, these results suggest that nucleolar processes mediated by MoRRP8 is pivotal for fungal development and pathogenesis.

• Journal of the Korean Society of Radiology
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• v.16 no.7
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• pp.1007-1014
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• 2022

Targeted radionuclide therapy (TRT) is a method of treating tumor cells using radiopharmaceuticals. Cells and nuclei constituting tissues of the human body are composed of spherical and oval shapes, but cancer cells are composed of various cell types. Therefore, this study analyzed the absorbed dose for each organelle according to the change in the size of the cell nucleus for beta-emitting nuclides during targeted radionuclide therapy through the Monte Carlo method. Cells were set in two sphere shapes, 5 ㎛ and 10 ㎛, and the internal structure was divided into cell nucleus, cytoplasm, and cell surface. Next, the absorbed dose according to the increase in the size of the cell nucleus was evaluated. As a result, ¹⁷⁷Lu among the target radionuclides showed the highest dose in all cell compartments. As the ratio of the nucleus in the cell increased, the absorbed dose on the cell surface increased, but the absorbed dose in the cytoplasm and nucleus tended to decrease. Accordingly, it is judged that it is important to select a radionuclide considering the size of cancer cells and determine an appropriate amount of radioactivity during targeted radionuclide treatment.

• Parasites, Hosts and Diseases
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• v.36 no.4
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• pp.227-234
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• 1998

Actin and tropomyosin of Cryptosporidium muris were localized by immunogold labeling. Two kinds of antibodies for actin labeling were used. The polyclonal antibody to skeletal muscle (chicken back muscle) actin was labeled on the pellicle and cytoplasmic vacuoles of parasites. The feeder organelle has showed a small amount of polyclonal actin antibody labeling as well. Whereas the monoclonal antibody to smooth muscle (chicken gizzard muscle) actin was chiefly labeled on the filamentous cytoplasm of parasites. The apical portion of host gastric epithelial cell cytoplasm was also labeled by smooth muscle actin together. The polyclonal antibody to tropomyosin was much more labeled at C. muris than host cells, so it could be easily identified even with low magnification (${\times}2,000$). The tropomyosin was observed along the pellicle, cytoplasmic vacuoles, and around the nucleus also. The skeletal muscle type actin seems to play a role in various celluar functions with tropomyosin in C. muris; on the other hand, the smooth muscle type actin was located mainly on the filamentous cytoplasm and supported the parasites firm attachment to host cells. Tropomyosin on the pellicle was thought to be able to stimulate the host as a major antigen through continuous shedding out by the escape of sporozoites or merozoites from their mother cells.

• Applied Microscopy
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• v.33 no.3
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• pp.243-250
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• 2003

Ultrastructural changes of the male germ cells and structure of spermatozoa in Paralichthys olivaceus were examined by means of the light and transmission electron microscopes. The spermatogonium has a large nucleus with a single nucleus with a single nucleolus in the interphase. Primary spermatocytes are identified by the formation of the synaptonemal complex in the karyoplasm. The secondary spermatocytes are more concentrated and contains numerous cell organelle in the cytoplasm. The nucleus of spermatid in spermiogenesis is more condensed in the karyoplasm, and show spherical structure in shape. Mitochondria of the spermatids are observed in the lower portion of the nucleus. The spermatozoon consists of the head, mid piece and tail. The acrosome is not observed in the head. Axial filaments of the flagellum consists of nine pairs of the peripheral microtubules and one pair of the central microtubules.

• Proceedings of the Botanical Society of Korea Conference
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• 1999.07a
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• pp.51-56
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• 1999

Plastids, which are organelles unique to plant cells, bear their own genome that is organized into DNA-protein complexes (nucleoids). Regulation of gene expression in the plastid has been extensively investigated because this organelle plays an important role in photosynthesis. Few attempts, however, have been made to characterize the regulation of plastid gene expression at the chromosomal structure, using plastid nucleoids. In this report, we summarize the recent progress in the characterization of DNA-binding proteins in plastids, with special emphasis on CND41, a DNA binding protein, which we recently identified in the choloroplast nucleoids from photomixotrophically cultured tobacco cells. CND41 is a protein of 502 amino acids which consisted of a transit peptide of 120 amino acids and a mature protein of 382 amino acids. The N-terminal of the 'mature' protein has lysine-rich region which is essential for DNA-binding. CNA41 also showed significant identities to some aspartyl proteases. Protease activity of purified CND41 has been recently confirmed and characterized. On the other hand, characterization of accumulation of CND41 both in wild type and transgenic tobacco with reduced amount of CND41 suggests that CND41 is a negative regulator in chloroplast gene expression. Further investigation indicated that gene expression of CND41 is cell-specifically and developmentally regulated as well as sugar-induced expression. The reduction of CND41 expression in transgenic tobacco also brought the stunted plant growth due to the reduced cell length in stem. GA3 treatment on apical meristem reversed the dwarf phenotype in the transformants. Effects of CND41 expression on GA biosynthesis will be discussed.

• Journal of Radiation Industry
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• v.10 no.1
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• pp.7-12
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• 2016

Ikaros, a transcription factor containing zinc-finger motif, has known as a critical regulator of hematopoiesis in immune system. Ikaros protein modulates the transcription of target genes via binding to the regulatory elements of the genes promoters. However the regulatory function of Ikaros in other organelle except nuclear remains to be determined. This study explored radiation-induced modulatory function of Ikaros in cytoplasm. The results showed that Ikaros protein lost its DNA binding ability after LDIR (low-dose ionizing radiation) exposure. Cell fractionation and Western blot analysis showed that Ikaros protein was translocated into cytoplasm from nuclear by LDIR. This was confirmed by immunofluorescence assay. We identified Autotaxin as a novel protein which potentially interacts with Ikaros through in vitro protein-binding screening. Co-immunoprecipitation assay revealed that Ikaros and Autotaxin are able to bind each other. Autotaxin is a crucial enzyme generating lysophosphatidic acid (LPA), a phospholipid mediator, which has potential regulatory effects on immune cell growth and motility. Our results indicate that LDIR potentially regulates immune system via protein-protein interaction of Ikaros and Autotaxin.

• The Journal of Korean Medicine
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• v.18 no.1
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• pp.430-445
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• 1997

In order to know the effects of Calculus $Bovis{\cdot}F디$ Ursi aqua-acupuncture ($C{\cdot}F$ aqua-acupuncture) to the liver damage, we carried out the treatment of $C{\cdot}F$ aqua-acupuncture and injection of Kam-Du-Tang on the liver damaged rat which is induced by aconitine, and then ultrastructural study has been to the liver tissue. The results were as follows: 1. In the hepatic cell of normal group, the nuclear envelope is round and electro-density of nucleoplasm is relatively low, and have one or two large nucleolus. Cell organelle is developed rough endoplasmic reticulum(RER) and many mitochondria, glycogen granules, smooth endoplasmic reticulum(SER) and Golgi apparatus. 2. In 24 hours control group, nuclear envelope is very irregular, RER and most of cell organell is shown that destroyed by aconitine. This is similar to the 48 hours control group. In 72 hours control group, RER is recovered somewhat but cristae of mitochondria is not seen the shape 3.In 24 hours $C{\cdot}F$ aqua-acupuncture group, nuclear envelope is very irregular and cristernae is very dilatable and many mitochondria is dilationed and the cristae is not definite like the control group. In 48 hours $C{\cdot}F$ aqua-acupuncture group, nuclear envelope is relatively round and chromatin is regular. Cristernae of RER and ribosme is somewhat imperfect but is similar the normal group, and the cristae of mitchondria is shown definitely like the normal group. In 72 hours $C{\cdot}F$ aqua-acupuncture group, nuclear envelope is round and cell organell is similar to normal group. 4. In 24 hours Kam-Du-Tang group, nuclear envlope is very irregular and cell organelles are destroyed by the effects of aconitine. In 48 hours Kam-Du-Tang group, nuclear envelope is somewhat irregular but chromatin is relatively regular. RER is seperated regularly through the cytoplasm, but cannot make the structure of lamina, and cistennae is very dilationed. many of glycogen granules is seperated regularly. In 72 hours Kam-Du-Tang group, RER makes the lamina. Mitochondria is a little but inner space is dilationed so the shape of is not definite and a lot of glycogen granules are accumulated in several places. It see the above result, hepatic cell that is damaged by aconitine is effected chiefly by the $C{\cdot}F$ acupuncture and effect of acupuncture is similar to the detoxicated effect of Kam-Du-Tang.

• Applied Microscopy
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• v.30 no.3
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• pp.265-272
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• 2000

In this study, the brachial ganglion of Octopus minor was investigated with light microscope and electron microscope,andthefollowingresultswereobtained. The brachial ganglions of the octopus, round in shapes , are located under each of suckers. Their sizes are proportional to those of the suckers. A brachial ganglion of round shape consists of cortex and medulla. In cortex, nerve cells exist collectively while neuropiles in medulla. Three kinds of nerve cells (large, middle, and small neurons) are found in the cluster of nerve cells. The small one is a round cell of about $0.9{\mu}m$ in diameter while the middle and large ones are an elliptical cell of $1.6\times1.3{\mu}m$ and an ovoid cell of $2.8{\mu}m$ in diameter, respectively. All of those cells look light due to their low electron densities , in which cell organelle are not well developed. It was also observed that the middle neurons are surrounded by median electron-dense neuroglial cells of pyramidal shapes and about $0.6\times0.4{\mu}m$ in sizes. In the neuropiles of medulla, dendrites and axons of various sizes make a complex net. They contain four kinds of chemical synaptic vesicles-electron-dense synaptic vesicle of 100 nm in diameter, median electron-dense synaptic vesicle of 90 nm in diameter, electron-dense cored synaptic vesicle of 90 nm in diameter, and electron-lucent synaptic vesicle of 50 nm in diameter.

• Korean Journal of Organic Agriculture
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• v.19 no.1
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• pp.109-120
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• 2011

Calyx-end browning in sweet persimmon (Diospyros kaki) fruits is the postharvest disorder during the storage and shows different proportions by the cultivars. This study was to evaluate fruit texture characteristics at harvest and to learn how browning in fruits affects the cell structures in different cultivars. Persimmon cultivars included 'Fuyu', 'Jiro', 'Uenishiwase', 'Daiandangam', and 'Ro-19', which were harvested at the end of October in 2003 and investigated after 100 days storage. Fruit texture varied with different cultivars. 'Jiro' and 'Ro-19' fruits did not have browning symptoms while 'Daiandangam' fruits had approximately 80% browning of them. There were no visual differences for the cell structure in fruit peels between fruits without browning, such as 'Jiro' and 'Ro-19', and fruits with browning, such as 'Fuyu', 'Uenishiwase', and 'Daiandangam'. The most outer layers in a 'Jiro' fruit peel arranged one to two epidermis which could not induce browning in the tissues, while 'Fuyu' had two to three layers, inducing a browning symptom. Although there were no differences for the tissue structure between browning and normal fruits, browning fruits did not have apparent cell organelle and proceeded degradation of cell walls in the flesh.