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T Naguro

Publications and source records attributed to T Naguro.

14 recordsLinked to original sources
PubMed1992

Olfactory epithelium in young adult and aging rats as seen with high-resolution scanning electron microscopy.

The present study uses mainly scanning electron microscopy to demonstrate the three-dimensional internal cell structures of rat olfactory epithelial cells. The aldehyde-prefixed osmium-DMSO-osmium (AODO) method devised by Tanaka and Mitsushima (1984) was applied to the present study to disclose intracellular structures such as endoplasmic reticulum, mitochondria, Golgi apparatus, and lysosomes. The spatial distribution pattern of these structures in olfactory and supporting cells is discussed, paying special attention to the formation of lipofuscin-like granules present in aged rats.

Aging↗
PubMed1992

A new approach to the study of ovarian follicles by scanning electron microscopy and ODO maceration.

The ultrastructure of the follicle-oocyte complex in rodents and humans was revealed by high resolution scanning electron microscopy (SEM) following the Osmium-DMSO-Osmium maceration method (TANAKA and NAGURO, 1981). In primary follicles, the majority of oocyte organelles such as mitochondria and Golgi complex components are concentrated in a juxtanuclear area. In particular, many spherical mitochondria are oriented all around the nucleus. After maceration of the ooplasm matrix, most of these mitochondria appear intermingled with numerous microtubules (MT) and associated with many Golgi vesicles. Such a nuclear polarization of organelles, essential to the oocyte metabolism, might depend upon a MT activity. MT might guide mitochondria to gather in the perinuclear region and further maintain their close associated to the nuclear envelope. A similar relationship among microtubules, vesicular Golgi complex and mitochondria has been also observed when, in maturing oocytes, these organelles migrate and gather in other areas of the ooplasm. A pattern common only to human developing follicles appears in the occurrence of long microvilli projected from follicle cells deep into the oocyte. These unusual microvilli running within the ooplasm are surrounded by several vesicles of the Golgi complex and endoplasmic reticulum, and often end close to the nucleus. In the antral follicle, the microvilli of corona cells, directed toward the oocyte (after their full exposure through the chemical dissolution of the zona pellucida matrix) are extremely numerous (up to 70/cell), long (up to 7/10 microns) and tortuous. They resemble epididymal stereocilia, may be ramified and possess bulbous tips. In contrast, oocyte microvilli are thin and short.(ABSTRACT TRUNCATED AT 250 WORDS)

Dimethyl Sulfoxide↗
PubMed1991

Association of cytoskeletons with the Golgi apparatus: three-dimensional observation and computer-graphic reconstruction.

The association of cytoskeletons with the Golgi apparatus (GA) in cultured 3Y1 cells was investigated by stereo electron microscopy of thick sections and computer-graphic reconstruction of serial thin sections. The 3-dimensional analysis has demonstrated that: 1) both microtubules (MT) and vimentin intermediate filaments (IF) were abundantly present in close vicinity to GA, and some of them were closely associated with GA; and 2) such GA-associated cytoskeletons were attached to GA either at their termini or at their lateral side. The present observations suggest that both MT and vimentin IF are responsible for maintaining the structural integrity of GA.

Animals↗
PubMed1990

The tannin-osmium conductive staining after dehydration: an attempt to observe the chromosome structure by SEM without metal coating.

The tannin-osmium conductive staining method was modified in order to observe chromosomal structures without metal coating. The treatment with tannic acid and OsO4, which has been used in aqueous solution in the original method, was performed in acetone solution after dehydration in the present study. The usefulness of this method is discussed showing ultrastructural images of chromosomes of Drosophila and Tradescantia, which can be achieved by the method.

Animals↗
PubMed1984

Freeze-fracture study of the plasma membranes of the septal olfactory organ of Masera.

The olfactory border and the apical cell contacts of the organ of Masera (MO) of the mouse were investigated by freeze-fracture electron microscopy. The olfactory border is mainly composed of the terminals of receptor and supporting cells. Cells with thick microvillus-like projections, though less frequent than the other two cell types, also contribute to the border. Olfactory knobs show transitions between those displaying numerous cilia and those characterized by few or no cilia. The olfactory cilia have a typical necklace of 6-9 rows of particles. The eruption of developing cilia seems to be preceded by the formation of circular arrays of particles. The density of intramembranous particles (IMP) per micron2 in P- and E-faces of the ciliary membranes is 1095 +/- 190 and 205 +/- 65, respectively. In the microvilli of supporting cells, the density of IMP per micron2 is 1800 +/- 270 for the P-face and 570 +/- 135 for the E-face. At the base of the supporting cell microvilli, rod-shaped particles are observed. The lateral plasma membranes of these cells bear orthogonal arrays of particles. In the apical region of the MO neuroepithelium, extensive zonulae occludentes are present which seal the intercellular cleft. The zonulae occludentes between supporting and receptor cells are composed of 5-13 junctional strands, usually arranged in an elongate network. Zonulae occludentes between supporting cells are, in addition to the elongate network, also arranged in a mesh-like pattern. Gap junctions, both associated with the zonulae occludentes and independent of them, are occasionally found between supporting cells. The results obtained indicate that important similarities exist between the neuroepithelium of the MO and the olfactory epithelium proper, whereas remarkable differences exist between the MO and the vomeronasal neuroepithelium.

Animals↗
PubMed1982

The vomeronasal epithelia of NMRI mouse. A scanning electron-microscopic study.

The features of the apical and lateral surfaces of cells of the vomeronasal epithelium were studied in adult male mice by scanning electron microscopy. Supporting cells and receptor cells of the neuroepithelium are covered with microvilli. Microvilli of the sensory cells are longer and thinner than those of the supporting cells. Additionally, the former differ in local distribution, orientation, occurrence of branching and appearance of the cell coat. The receptor-free epithelium consists most likely of one cell type only, which shows different structural modifications including the presence, number and length of microvilli and cilia. In the transitional region, between the neuroepithelium and the receptor-free epithelium, immature receptor cells are present.

Animals↗
PubMed1982

Effect of N-methyl-formimino-methylester on the vomeronasal neuroepithelium of mice.

N-methyl-formimino-methylester (MFM), a highly volatile chemical substance, causes massive, transient sensory-cell degeneration in the main, but not in the vomeronasal olfactory sensory epithelium of mice. After MFM-treatment it appears possible to study the accessory olfactory system after chemical "deafferentation" of the main system.

Animals↗
PubMed1980

Polytene chromosomes observed scanning electron microscope.

Polytene chromosomes of the salivary gland cells from Drosophila melanogaster were observed by means of scanning electron microscopy using mainly the cracking method. Band and interband regions were visible as transverse striped patterns consisting of multiple, side-by-side fibres. Band regions seemed much more compact than interband ones. In the cross section of the entire chromosome, about 1,100 chromatid fibres could be counted. Intranuclear fine filaments could be recognized surrounding the polytene chromosomes each of whose diameters were almost the same (160--200 A). Field emission scanning electron micrographs showed the unit chromatid fibres clearly in very high magnification.

Animals↗
PubMed1976

Scanning electron microscopic observation on intracellular structures of ion-etched materials.

Ion-etching technique on the cracked surface of biological material may give a plastic visualization of intracellular structures under the scanning electron microscope, because membraneous structures in the cell are generally etch-resistant and the cytoplasmic matrix is easily ion-etched. Mild ion-etching using low voltage was applied to the cells of the pancreas. Nuclear pores were clearly disclosed but were enlarged slightly in the process of etching. Endoplasmic reticulum with ribosomes, Golgi apparatus, mitochondria, some filamentous structures and crystalline inclusions (B cell granules) were also effectively disclosed by ion-etching technique. It is necessary, however, to compare the etched specimens carefully with non-etched ones to determine whether given structures observed are intrinsic ones or artifacts caused by etching.

Animals↗