• Applied Microscopy
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• v.42 no.4
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• pp.186-193
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• 2012

The ultrastructure of the secretory granules of the submandibular gland was examined in the Korean spider shrew, Sorex caecutiens, lesser white-toothed shrew, Crocidura suaveolens and big white-toothed shrew, C. lasiura. The mucous and serous acinar granules of S. caecutiens with a border of the lucid corona differed from those of C. suaveolens and C. lasiurar with a dense lateral border. The mucous acinar granules of C. lasiura with several bands producing a variety of patterns in the matrix were similar to those of C. suaveolens. The serous acinar granules of C. lasiura had a homogenous pale center surrounded by minute dense specks or had an unusual substructure showing a geometric pattern according to the inclusions in the pale matrix of the granules. This is the first report of an unusual substructure showing a geometric pattern of the serous acinar granules of C. lasiura. The myelin-like body was observed in the granular duct cell of the three species of shrew. The myelin-like body of S. caecutiens with layers of unit membranes was different from that of C. suaveolens and C. lasiura with paired membranes. Therefore, the layers composing of the paired membranes of the myelin-like body might be one of the characteristics of Crocidura.

• Applied Microscopy
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• v.35 no.2
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• pp.65-72
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• 2005

The ultrastructure of submandibular gland was examined in the lesser white-toothed shrew, Crocidura suaveolens. The submandibular gland of C. suaveolens was a mixed gland composed of serous and mucous acinar cells. Secretory granules from the acini were discharged through the salivary ducts into the oral cavity. Serous and mucous acinar cells had well developed rough endoplasmic reticulum and mitochondria and large amount of granules. In case of serous acinar granules, an immature granule was formless and had only dense specks, and a matured granule was a complete round type delimiting by a single membrane and had a homogeneous dense center with dense specks on the border. In case of mucous acinar granules, while an immature granule was a round type and had an only homogeneous matrix and an indistinct limiting membrane, a mature granule was an even round type having a variety of pattern with several dense bands into the homogeneous matrix and had a distinct membrane. Therefore, a mature mucous acinar granule of C. suaveolens was not only distinct from those of the other mammalian species to have a variety of pattern but also from those of C. lasiura to have an even round type. A great serous-like secretory granules and Myelin-like body were observed in the cytoplasm and lumen of granular duct cells. Myelin-like body, a characteristic structure only reported in salivary gland of three shrews, was discharged from secretory cell into lumen by the manner of exocytosis which has little differences from discharging manner of secretory granules.

• Applied Microscopy
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• v.35 no.2
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• pp.57-64
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• 2005

The ultrastructure and histochemical characteristics of the submandibular gland was examined in the big white-toothed shrew, Crocidura lasiura. A submandibular gland of Crocidura lasiura was a mixed gland composed of serous and mucous acinar cells. Secretory granules from the acini were discharged through the intercalated duct, the granular duct and the striated duct into the oral cavity. Serous and mucous acinar cells and granular duct cells had large amount of rough endoplasmic reticulum, free ribosome and prominent Golgi apparatus at the basal cytoplasm of the cell, and many granules at the apical cytoplasm. Oval type serous granules had a homogeneously pale round shape of bead at the center. Mucous granules were distinct from those of the other mammalian species having variety patterns with several dense bands into homogeneous pale matrix. A serous-like secretory granules and myelin-like body were observed in the cytoplasm and the lumen of granular duct cells. The myelin-like body is a characteristic structure only reported in the salivary glands of two shrews, Suncus murinus and C. dsinezumi. Striated duct cell had numerous well-developed mitochondria but secretory granule was not shown at all.

• Applied Microscopy
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• v.25 no.1
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• pp.1-14
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• 1995

The purpose of this study was to investigate the main sensory trigeminal nucleus in the aging rat brain by means of electron microscope. Male Sprague-Dawley rats, two (control group) and thirty six (aging group) months of age, were used. These animals were sacrificed by perfusion fixation with 2.5% glutaraldehyde-2.0% paraformaldehyde (0.1M phosphate buffer, pH 7.4) under sodium pentobarbital. The objective area was punched out with a sharp-edged metal cylinder of 0.8 mm in diameter. These blocks of tissue were then washed in 0.1M phosphate buffer, postfixed in 2% osmium tetroxide, dehydrated in a graded series of ethyl alcohol, and embedded in Epon 812. Thin sections were cut with Super Nova ultramicrotome, pick up on grids and double stained with lead citrate and uranyl acetate, and observed in JEOL 100B electron microscope. The results were as follows: 1. In the control group, the neuronal cell body of the main sensory trigeminal nucleus was filled with nucleus, Golgi complex, Nissl substance, mitochondria, microfilaments and microtubules. However, few Nissl substances are seen in neuronal cell body. Axoaxonic synapse, axodendritic synapse, axosomatic synapse, axospinous synapse, myelinated and unmyelinated nerve fibers were well organized around cell bodies. Neurons with abnormal changes were not seen. 2. In the aging group, the neuronal cell body of the main sensory trigeminal nucleus contained large number of lipofuscin granules, dense body and swollen mitochondria. Terminal boutons contained glycogen, crystal-like vesicle and membranous indicating first signs of degeneration. The dendrites were found to be in synaptic contact with altered axon terminals. Frequently axons filled with dark axoplasn and splitted myelin sheath were noticed.

• Applied Microscopy
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• v.6 no.1
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• pp.21-32
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• 1976

The origins and the functions of the multi vesicular bodies and the various structures of the membranes related to the cytolysomes were studied in the mycelium cells of Rhizopus nigricans, Aspergillus niger and A. ochraceus, in the hymenium and basidium cells of Agricus bisporus sand Rhizopogon rubesecens, in the cells of assimilation tissue of Marchtantia polymorpha and Pogonalum inflexum and in the mesophyll cells of Pteridium aqiulinum, Pinus densiflora, Ginkgo biloba and Panax ginseng fixed with glutaraldehyde-paraformaldehyde-$ OsO_4$. In Rhizopus nigricans, Aspergillus niger, A. ochraceus, Agricus bisporus sand Rhizopogon rubescens, the concentric multilamellar, multivesicular, myelin-vesicle-tubular and concentric parallel-lamellar complexes were originated from the plasmalemma, while in Marehantia polymorpha, Pogonatum inflexum, Pteridium aquilinum, Pinus densiflora, Ginkgo biloba and Panax ginseng, they were originated from plasmalemma and the cytoplasm. The structures originated from the plasmalemma may be grouped into multi vesicular body and myelin-like structure, both forming the secondary vacuoles or protruding into the central vacuoles and finally degrading, In some cases, endoplasmic reticulum within the cytoplasm encloses some part of the cytoplasm to form a circle where the membranous lamellae increase in number, while the enclosed cytoplasm decrease to be eventually replaced by the multilamellar structure which is released into the vacuoles and subsquently degraded. The structures originated from the cytoplasm are believed to be the cytosegresomes or cytolysomes closely related to the differentiation of the vacuoles. The possible fate of these structures are also discussed.