• Applied Microscopy
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• 제28권3호
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• pp.391-398
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• 1998

The morphological phenotype on ocellus of Drosophila rdgC mutant was observed with electron microscope. The result showed the particular phenotype that was not found in other retinal degenarative mutants. The most distinct difference was the orientation of photoreceptor cells. The photoreceptor cells did not attached to corneagenous cells but dropped under corneagenous cells and assembled around newly formed space. Enormous multivesicle bodies caused by the degeneration of photoreceptor cells were frequently found. Rhabdomeres were also severely degenerated in consequence of the mutant. Another degeneration was found in a part of photoreceptor cell, but the degeneration of subrhabdomeric cisternae (SRC) was not found. It was a ovious difference of rdgC comparing with other two retinal degenerative mutants, rdgA and rdgB. As a result, rdgC mutant was affected on the attachment between photoreceptor cells and corneageneous cells, and it suggested the defect of cell-cell attachment. In addition, rdgC mutant was accompanied by the defect not only in retina but nerve system. The results were agreed to the reference discussion that the rdgC molecule is exist in the nerve.

• Applied Microscopy
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• 제25권4호
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• pp.115-123
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• 1995

This study was carried out to observe the functional ultrastructures of photoreceptor cells in frog(Rana catesbeiana) retina using transmission electron microscope. The photoreceptor cells are divided into two types-rod and cone cells-consist of outer and inner segment. The long outer segment of rod cell contains dense stacks of membrane and formed vertical and horizontal folds. The outer segment of cone cell is small, and vertical and horizontal folds are not exist. The electron dense cytoplasm of rod cell contains compact mitochondria, Golgi complexes, and endoplasmic reticula. The inner segment of cone cell shows low electron density and contains a large lipid droplet in the upper part of inner segment. In addition, cone cell contains many mitochondria, Golgi complexes. rough endoplasmic reticula, ribosomes and numerous glycogen particles. It is believed that these ultrastructural characteristics are closely associated with photoreceptive function of photoreceptor cells in frog retina.

• 생명과학회지
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• 제9권3호
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• pp.308-313
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• 1999

Ocellar morphological abnormality was studied in Drosophila rdgA mutant. In the mutant, ocellar photoreceptor cells were generally affected by the defection of rdgA molecules. Among organelles of photoreceptor cell, rhabdomeres were remarkably degenerated. The rdgA molecule, diacylglycerol kinase, was localized around SRC just below the rhabdomeric region. As a secondary phenomenon of photoreceptor degeneration, rER, multivesicular body and multilamella body were appeared in cytoplasm and these were known as to clean the cellular debris. These morphological abnormality was generally observed in degenerating cells. In Drosophila mutant, the degeneration of ocellar photoreceptor cell was facilitated to time. More intense morphological defection was observed in rdgA^{ks60} rather than in yw;rdgApc47.

• Applied Microscopy
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• 제50권
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• pp.11.1-11.3
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• 2020

The human turbinate-derived mesenchymal stem cells (hTMSCs), which were DiI-labeled and transplanted into the subretinal space in degenerating mouse retina, were observed in retinal vertical sections processed for rhodopsin (a marker for rod photoreceptor) by confocal microscope with differential interference contrast (DIC) filters. The images clearly demonstrated that DiI-labeled hTMSCs have rhodopsin-immunoreactive appendages, indicating differentiation of transplanted hTMSC into rod photoreceptor. Conclusively, the finding suggests therapeutic potential of hTMSCs in retinal degeneration.

• Applied Microscopy
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• 제25권2호
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• pp.39-52
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• 1995

Pinealocytes in the lower vertebrate are known to have photoreceptive function. These photoreceptor cells have been characterized morphologically in various species of lower vertebrates. No such ultrastructural studies, however, were reported in fresh water turtle. The purpose of this study is to characterize the pinealocytes and the phylogenetic evoluton of these cells is discussed in terms of functional analogy. I. Light microscopy: The pineal body was divided into incomplete lobules by connective tissue septa containing blood vessels, and parenchymal cells were arranged as irregular cords or follicular pattern. In the lobules, glandular lumina were present and contained often densely stained materials. II. Electron microscopy: The pineal parenchyma had three categories of cells: photoreceptor cells, supportive cells and nerve cells. The photoreceptor cells had darker cytoplasm compared to the supportive cells, and the enlarged apical cytoplasm(inner segment) containing abundant mitochondria and dense cored vescles protruded into the glandular lumen in which lamellar membrane stacks(outer segment), dense membranous materials, and cilia were present. Some of these lamellated membrane stacks appeared to be dege-nerating while others were apparently newly formed. Constricted neck portion of the photoreceptor cells contained longitudinally arranged abundant microtubules. centrioles and cross-striated rootlets. Cell body had well developed Golgi apparatus, abundant mitochondria, dense granules($0.5{\sim}1{\mu}m$), dense cored vesicles($70{\sim}100nm$), and rough endoplasmic reticulum occasionally with dense material within its cisterna. Basal portion of the photoreceptor cells had basal processes often with synaptic ribbons, which terminate in the complicated zone of cellular and neuronal processes. Synatpic ribbons often made contact with the nerve processes and the cell processes of neighboring cells. In some instances, these ribbons were noted free within the basal process and were also present at the basal cell mem-brane facing the basal lamina. Obvious nerve endings with clear and dense cored vesicles were observed among the parenchymal cells. Photoreceptor cells of the snapping turtle pineal body were generally similar in fine structure to those of other lower verterbrates reported previously, and suggested to have both photoreceptive and secretory functions which were modulated by pinealofugal and pinealopedal nerves. The supportive cells were characterized by having large dense granules($0.3{\sim}1{\mu}m$), abundant ribosomes, well developed Golgi apparatus and rough endoplasmic reticulum. These cells were furnished with microvilli on the luminal cell surfaces, and often had centrioles, striated rootlets, abundant filaments especially around the nucleus, and scattered microtubules. Some supportive cells had cell body close to the lumen and extended a long process reaching to basal lamina, which appeared to be a glial cell. Nerve cells within the parenchyma were difficult to identify, but some large cells located basally were suspected to be nerve cells, since they had synaptic ribbon contact with photoreceptor cells.

• Journal of Photoscience
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• 제9권2호
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• pp.272-274
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• 2002

The anterior brain vesicle of ascidian larvae contains two distinct pigment cells. Ultrastructure of these pigment cells has been shown that the anterior pigment cell is an otolith for perception of gravity and the posterior pigment cell is an ocellus for light reception. The larva has remarkably simple central nervous system (CNS) composed of about 330 cells. We focused to study neural networks of visual systems. In the present paper, we report the whole structure of the photoreceptors of the ascidian larva visualized by an antibody against arrestin. Visual arrestin is the key protein for the termination of phototransduction and one of the abundant proteins in photoreceptors. Recently, we cloned an arrestin homologue gene, Ci-arr and the expression of Ci-arr was found to be restricted to the photoreceptors in the ocellus. To study the whole structure of the photoreceptors in the larva, we prepared an antibody against Ci-Arr. It is found that anti Ci-Arr antibody specifically stains the photoreceptors, including the cell bodies, the axons, and the nerve terminals. The photoreceptor cell bodies lies in row outside the pigment cup which penetrate the pigment cell and is continuous with the outer segments of the photoreceptor cell, inside the concavity of the pigments. The axons form bundle into a single tract. The tract extends toward the midline, where the nerve terminals diverge and seem to form synapses

• Applied Microscopy
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• 제30권3호
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• pp.255-264
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• 2000

메기 송과체를 대상으로 3차원적 전자현미경법을 이용하여, 송과체를 구성하는 신경세포 및 광수용세포 돌기들의 위치적 상호관계를 3차원적으로 구명하고자 하였다. 광수용세포의 돌기들은 서로 복잡하게 얽혀 있었으며, 다른 세포질내로 돌기의 일부가 파고드는 양상을 보이는 것도 있었다. 신경세포 돌기는 이들 읽혀 있는 광수용세포 돌기 사이를 주행하면서 여러군데서 리본연접을 형성하고 있었는데, 광수용세포내의 이들 리본연접의 수는 위치에 따라 다양하였다. 한편 송과강내에서는 탐식되기 전의 광수용세포 외절에 대식세포가 접근해 있는 것도 관찰되었다. 이상의 관찰결과, 메기 송과체의 광수용세포의 기저돌기는 다양한 형태이며, 특히 인접부위로 주행하는 신경세포의 돌기와 연접을 형성하기 위해 또 다른 가지를 내고 있음을 알 수 있었다.

• Applied Microscopy
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• 제28권3호
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• pp.363-377
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• 1998

After the investigation on the eye of Incilaria fruhstorieri with light and electron microscopes, the following results were obtained. The eye of Incilaria fruhstorferi comprises cornea, lens, vitreous body, retina, and optic nerve inward from the outside. Cornea is composed of squamous, cuboid, columnar and irregular cells, which appear to be light due to their low electron density. In their cytoplasms, glycogen granules, multivesicular body, and nucleus were observed. Vitreous body, located behind non-cellular transparent lens, is filled with long and short microvilli protruding from the retinal epithelia. Retinal epithelium, the organ to perceive objects, is divided into four parts; microvillar layer pigment layer, nuclear layer, and neutrophils layer, from the apical portion. Microvillar layer consists of the type-I photoreceptor cells and pigmented granule cells. In the apical portion of their cytoplasms, long microvilli (length, $19{\mu}m$) , short microvilli (length, $8{\mu}m$), and rolled microvilli grow thick in the irregular and mixed forms. Photoreceptor cells are classified into type-I and type-II, according to their structures. The type-I cell has the apical portion rising roundly like a fan and the lower part which looks like the helve of a fan. In the cytoplasm of the apical portion, there are clear vesicles, cored vesicles, ovoid mitochondria, and microfilaments, and in the cytoplasm of the lower part, photic vesicles with their diameters about 60nm aggregate densely. The type-II photoreceptor cell, located at the lower end of the type-I cells, has a very large ovoid nucleus 3nd no microvilli. In the cytoplasm of the type-II cell, the photic vesicles with sizes 60nm aggregate more densely than in the cytoplasm of the type-I cell. Pigmented cells are classified into type-A and type-B, according to their structures. The type-A is identified to be a large cell containing round granules (diameter, $0.5{\mu}m$) of very high electron density, while the type-B is identified as a small cell where the irregular granules (diameter, $0.6{\mu}m$) of a little lower electron density amalgamate. Nuclear layer ranges from the bottom of pigment layer to the top of the capsule, and contains three kinds of nuclei (nuclei of the type-II photoreceptor cell, pigmented granule cell, and accessory neuron). The capsules covering the outmost part of the eyeball are composed of collagenous fiber and three longitudinal muscle layers (the thickness of each longitudinal muscle layer, $0.4{\mu}m$) and thick circular muscle layer (thickness, $0.3{\mu}m$). Around the capsules, there is a neurophile layer consisting of neurons and nerve fibers. Each neuron has a relatively large ovoid nucleus for its cytoplasm, and in the karyosome, large lumps of keterochromatin form a wheel nucleus.

• 한국발생생물학회지:발생과생식
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• 제23권2호
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• pp.171-181
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• 2019

To produce healthy and stable seed production, we need to obtain information and understand vision that affects behavior of red spotted grouper. We examined their expression and retinal development during the juvenile development. Short-wavelength sensitive opsin (SWS2), a cone photoreceptor, began to be expressed from lens and ear vesicle formation stage and its expression increased until 10 days after hatching (dah). In case of middle-wavelength sensitive opsin (MWS), its expression was detected at 3 dah and reached the highest level at 21 dah. The expression of long-wavelength sensitive opsin (LWS) was first observed from 3 dah and their expression decreased thereafter. Rhodopsin, a rod photoreceptor, was found to be expressed from 2 dah and its expression reached the highest level at 50 dah. The outer nuclear layer (ONL), inner nuclear layer (INL) and ganglion cell layer began to differentiate at 2 dah, while choroid first appeared at 4 dah so that the eyes became black. These results indicate that the development of retina mostly completes around 4 dah. It seems that the development of the retina and the expression of the opsin genes are closely related to the behavior such as hunting prey, considering that the timing of the completion of the development of the retina, the timing of gene expression, and the timing of completion of yolk absorption are similar.

• Journal of Photoscience
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• 제9권2호
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• pp.21-24
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• 2002

Pineal organs of poikilotherm vertebrates transform the environmental light information into a humoral message and a neuronal activity. The former is melatonin, and the latter is modulation of the impulse in ganglion cells. The ganglion cells are physiologically classified into luminosity (achromatic) type and chromatic one, as the neural activity is modulated in two ways. We attempted to classify the pineal ganglion cells with morphological characteristics by means of the three- dimensional reconstruction method. In the pineal ganglion cells of river lamprey, there are two different features, oval and spherical. For comparison of their projection region in the brain, the tracing investigation was also carried out. The application of the neural tracer near mesencephalic tegmentum showed that only oval-shaped ganglion cells were labeled in the pineal organ. These results suggest that the oval-shaped ganglion cell is functionally different from the spherical one.