• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.3
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• pp.285-296
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• 1995

Anatomical studies of sink tissues are required for better understanding the biological plant growth system and energy metabolism. Kinematics of root growth zones of two genotypes of tall fescue (Festuca arundinacea Schreb.) receiving 50 or 200 ppm N were determined. Longitudinal anatomy and cell dynamics of root growth zones were studied and calculated. The root growth zone is organized similarly to the leaf growth zone which has cell division, elongation, and maturation zones, but the root growth zone is only about 3.0 mm long compared to 25 to 30 mm for the leaf growth zone. The root cap extends about 0.4 to 0.5 mm from the apical initial, while the cell elongation zone for both cortical and metaxylem cells extends about 3.3 mm from the apical initial for both genotypes and N levels. Root cap cells elongate from an initial length of about 5$\mu{m}$ long to a final length of about 40$\mu{m}$ before being sloughed. Initial lengths of cortical and metaxylem cells were about 8.5 $\mu{m}$ and 13.0 $\mu{m}$, respectively. Elongation of cortex and metaxylem cell showed sigmoidal curves with final lengths of about 120 $\mu{m}$ for cortex cells and 650 $\mu{m}$ for metaxylem cells. Initial size and final size for both types were not affected by N level, but cell fluxes and cell elongation rates of cortical and metaxylem cells were about double in low N. Cell production rates were about 5 to 6 times higher in cortical cells than in metaxylem cells. Differences in N caused a larger change in cell production rate, duration of cell elongation, and relative cell elongation rate than did the genotypes. These data indicate that N application affects root growth longitudinally by changing cell production rate and elongation rate.

• 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.

• Applied Microscopy
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• v.24 no.4
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• pp.1-12
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• 1994

Various plastids in leaf and bracteal tissues of Cannabis sativa L. were examined by electron microscopy. Young chloroplasts without starch grain in mesophyll cells were ellipsoidal, and osmiophilic globules within them were common in stroma. During the plastid differentiation, the mature chloroplasts in mesophyll were changed in shape depending on the numbers and sizes of starch grain in stroma. Electron-dense granular substances were occurred along the outer membrane of chloroplasts in mesophyll. Typical plastids with reticulate body were present in the glandular trichomes. Electron-grey material appeared along the surface of a plastid. A light area in reticulate body is considered to represent junction point of thylakoids.

• Journal of the KSME
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• v.51 no.10
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• pp.34-38
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• 2011

이 글에서는 유체의 유동에 기인한 전단응력이 세포에 가해질 때 그 전단응력의 크기 및 세포의 종류에 따른 세포의 상태 변화를 관찰하는 연구 동향에 대하여 소개하고자 한다.

• Applied Microscopy
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• v.31 no.1
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• pp.101-108
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• 2001

Five kinds of neurosecretory cells (type-A, B, C, D and E) and neuropiles surrounding them were observed in the visceral ganglion and the right parietal ganglion of the African giant snail, Achatina fulica, by transmission electron microscopy. Type-A cells (diameter, $35{\mu}m$) are the most popular cells in the cortex of the two ganglions, which are of triangular or irregular forms. In their cytoplasm, there are found large granules of 1 fm in diameters and small round granules of about $0.1{\mu}m$ in diameters. Small granules are classified into the ones of high electron density and the others of middle electron density. Type-B cells (diameter, $19\times12{\mu}m$) are evenly distributed over various portions of cortex and medulla of the two ganglions. They are similar to type-A cells in shapes. The cytoplasm of type-B cells is crowded with high electron dense granules of about $0.1{\mu}m$. Round granules of about $0.7{\mu}m$ in diameters are also found but rarely. Type-C cells are the smallest cells whose sizes are about $8\times6{\mu}m$. Each of them contains a large nucleus of about $6\times5{\mu}m$. Its cytoplasm is full of electron dense granules of about $0.23{\mu}m$, each of which is artually an assembly of tiny granules of about $0.03{\mu}m$. Type-D cells are middle-size cells of about $28\times20{\mu}m$, which take ellipsoidal or irregular forms. They are found in the cortex more than in the medulla. Their cytoplasm looks dark due to the high electron density and, in it, two kinds of round granules whose sizes are $1.6{\mu}m$fm and $0.6{\mu}m$, respectively, are observed. Type-E cells are large cells of about $100\times50{\mu}m$, which are rarely found in the upper and middle portions of the two ganglions. The nucleus of the cell, which is very large $(70\times30{\mu}m)$ for the cytoplasm, contains electron dense round granules of diverse sizes (diameters, $1\sim0.2{\mu}m$). The surface of the cell protrudes filopodia of various forms and phagocytizes decrepit cells. Neuropiles are surrounding the neurosecretory cells. In nerve fibers, synaptic vesicles are observed, which are classified into six classes according to their electron densities , sizes and shapes.

• Korean Journal of Plant Tissue Culture
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• v.28 no.6
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• pp.311-315
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• 2001

The relationship among leaf size, leaf protoplast (cell) size, chloroplast size, and chloroplast number were investigated in tobacco and Arabidopsis thaliana at various developmental stages. In tobacco, protoplasts, less than 15.6 ${\mu}{\textrm}{m}$ in diameter had less than 20 chloroplasts, 0.93 ${\mu}{\textrm}{m}$ in thickness and 3.3 ${\mu}{\textrm}{m}$ in length on average. As protoplast size increased from 30 ${\mu}{\textrm}{m}$ to 45 ${\mu}{\textrm}{m}$ in diameter, chloroplast size remained the same (1.57 ${\mu}{\textrm}{m}$ in diameter and 5.55 ${\mu}{\textrm}{m}$ in length on average), but chloroplast number increase from 42 to 101 on average. A similar relationship was also observed in A. thaliana. The ratio of total chloroplast volume to protoplast volume was constant (0.105 in tobacco and 0.325 in A. thaliana) over various developmental stages.

• Journal of Dental Rehabilitation and Applied Science
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• v.34 no.3
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• pp.246-250
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• 2018

Ameloblastoma is a benign neoplasm originating from odontogenic epithelium. It is the most common neoplasm in the jaws and is characterized by aggressive behavior and local invasion. Unicystic ameloblastoma (UA) has a unilocular feature in radiologic examination and a cystic feature histologically. Decompression and marsupialization are conservative method of treatment of large UA. The purpose of decompression and marsupialization are size reduction of the mass, which makes it easy to handle at total enucleation with protection of nerve damage and facial deformity. Here we report successful conservative treatment of extensive UA using decompression and marsupialization with a review of literatures.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.4 no.1
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• pp.79-90
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• 1993

With immunohistochemical method, We have examined the distribution, the size, the number, and the morphology of somatostatin-immunoreactive neurons in the cerebral cortex of rats at the 1st. 2nd, 3rd, 4th postnatal week and the 2nd and 3rd months of age. The results are summarized as follows : 1) Strongly immunoreactive somatostatin neurons were found in the layer V and VI at the first postnatal week and then they were observed to be densely populated in the layer II and III from the 3rd postnatal week on as in the adult rat. 2) The size of the neuron was largest at the 2nd postnatal week while the number of the neurons was greatest in the 1st or 2nd postnatal week, depending on the different areas of the cortex. Overall the postnatal development of somatostatin neurons are well corresponds with the general principle of neuronal development of CNS.

• Applied Microscopy
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• v.17 no.1
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• pp.177-184
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• 1987

Endocrine cells in the pyloric region of the hedgehog were studied ultrastructurally. 4 types of endocrine cells classified as gastric-type EC, ELC, $D_1$, and G cells were observed in this region. The gastric-type EC cells contained pleomorphic granules with high electron density and highly dense bodies in a dense matrix. ECL cells were characterized by the presence of round or oval granules with high electron density. Some granules of ECL cells showed a small amount of content or empty. $D_1$ cells contained round and small granules with low electron density. They occasionally showed a narrow halo between the limiting membrane and the dense materials. G cells were characterized by the presence of round or oval granules with low electron density. Some granules of these cells showed a narrow halo between the limiting membrane and the core.

• Journal of Life Science
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• v.8 no.4
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• pp.449-456
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• 1998

Using morphometric technique, the present study was made of the kidney of rabbit embryo in the 13 days of the gestation. Their section areas of the renal tubules and the glomerular cells were compared with the those of adult rabbit, 1. In the developing renal tubule, the tubular section areas were larger than that of the adult, but the nuclear section areas of tubular calls were smaller than the adult. The microvilli of their cell surface were poorly developed, and their cytoplasm contained well developed mitochondria with euchromatic nucleus. 2. In the developing glomeruli. the nuclear section area of the cells of the parietal layer, the podocytes, and the endothelial cells were similar size, but their nuclei were larger than those of the adult. The cytopalsm of the podocytes contained well-developed rough endoplasmic reticulum, Golgi apparatus, and round mitochondria.