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Biomedical subjects

M Komatsu

Publications and source records attributed to M Komatsu.

At least 361 records · Page 20Linked to original sources
PubMed1978

Some observations on ciliogenesis in the oviduct epithelium of the mouse.

Ciliogenesis in the epithelium of the oviduct ampulla of 5-9 day-old mice has been investigated by electron microscopy. As reported by many investigators, fibrous granules, deuterosomes, and procentrioles are important for ciliogenesis. After injection of colchicine, fibrous granules disappear, while numerous coated vesicles and lysosome-like dense bodies appear in the same region, and the formation of deuterosomes and procentrioles is impeded. In the ciliogenic cell, the Golgi apparatus, consisting of numerous vesicles, is very well developed, and a large number of microtubules are distributed between the supranuclear and apical cytoplasm. In addition to these, many small vesicles, some of which are fused with the plasma membrane, occur in the apical cytoplasm. These vesicles, which may be derived from the Golgi apparatus, are considered to be necessary for the apical plasma membrane, because the protrusion of cilia requires additional plasma-membrane substance during their differentiation and development. The microtubules, some of which are connected with these vesicles, might play some role in the movement of these vesicles from the Golgi field to the apical cytoplasm. When colchicine is administered to suckling mice, formation of microtubules is blocked in the upper part of the ciliated cell, and the apical vesicles disappear. This also indicates that the microtubules bring the vesicles from the Golgi field to the apical region of the cell.

Animals↗
PubMed1978

Freeze-fracture images of the zonula occludens in the mouse oviduct epithelium.

Freeze-fracture images of zonulae occludentes of the oviduct epithelium of adult mice were observed in the electron microscope. The structure of zonulae occludentes varies depending on the types of oviduct epithelial cells. Those between two secretory cells consist of 5--14 (9.2 +/- 2.0) strands interposed between the luminal and the lateral plasma membrane. The strands run irregularly making well developed anastomoses with one another. The tight junction between two ciliated cells consists of 4--14 (8.5 +/- 2.3) strands. Among them the upper 3--9 strands are unique in shape. The strands run regularly, compactly and parallel to the luminal surface and to each other with a few anastomoses. The distance between the adjacent strands is about 40 nm. Under this characteristic part several strands are very loosely distributed and run irregularly. The pattern of the strands in the zonula occludens between a secretory cell and a ciliated one resembles that between adjacent ciliated cells. The junction consists of 4--13 (8.3 +/- 2.0) strands. The characteristically dense and parallel arrangement of the strands demonstrated in this study is presumed to be related to the ciliary movement. All the zonulae occludentes in the mouse oviduct epithelium are "very tight" in type. No large gap junctions are seen in the mouse oviduct epithelium.

Animals↗
PubMed1976

Inhibition of photophosphorylation by ATP and the role of magnesium in photophosphorylation.

ATP and pyrophosphate at high concentration (greater than 1 mM) inhibited photophosphorylation of isolated spinach chloroplasts in the normal salt medium and did not cause stimulation of electron transport. The inhibition of photophosphorylation by ATP or pyrophosphate was shown to be abolished by the addition of excess MgCl2, ADP and phosphate. It has been demonstrated that the rates of photophosphorylation in the absence and presence of ATP or pyrophosphate are determined similarly by the concentrations of magnesium-ADP (Mg - ADP-) and magnesiumphosphate (Mg - Pi) complexes. It is highly probable that Mg - ADP- and Mg - Pi, but not free ADP and free phosphate, are the active form of the substrates of photophosphorylation. This is in support of the view that ATP inhibits photophosphorylation by decreasing the concentration of Mg2+ which is available for the formation of the complex with ADP and phosphate.

Adenosine Diphosphate↗
PubMed1976

Kinetics of protein synthesis and release in the STH-cell of the mouse anterior pituitary as revealed by electron microscopic autoradiography of 3H-amino acids.

In order to investigate the kinetics of the synthesis and release of the secretory protein in the STH-secreting cell of the pituitary anterior lobe, studies were made using the electron microscopic autoradiography of 3H-amino acids. Each mouse received an intravenous injection of 2.8 mCi of 3H-amino acids consisting of equal amounts of 3H-leucine, 3H-tyrosine, 3H-lysine, 3H-histidine and 3H-glycine. The animal was sacrificed at 3, 5, 15 and 30 min, 1, 2, 4, 8 and 24 hrs after the injection. Although the whole silver grains are very few 3 min after the injection, half of the grains are recognized over the r-ER (47.1%); the Golgi apparatus already shows a few grains (5.9%). Total silver grains over the STH-cell increase in number with the lapse of time; the ratio of the grain number over the r-ER to the total grains over the whole cell decreases gradually, while the ratio of the grain number over the Golgi apparatus increases to reach a peak about 30 min after the injection (40.1%) and then decreases gradually. The ratio of the number of labelled granules to that of total granules increases slowly until 24 hrs after the injection (3 min: 0%, 5 min: 0.8%, 30 min: 3.9%, 2 hrs: 5.0%, 8 hrs: 8.0%, 24 hrs: 12.3%). It is concluded that the turnover in synthesis and release of exportable protein in the mouse STH-cell is very slow as compared with that of the thyroid and parathyroid cell.

Amino Acids↗
PubMed1976

Development and metamorphosis of the sea-star, Astropecten scoparius Valenciennes.

1. Astropecten scoparius develops to a bipinnaria with simple ciliary bands and short bipinnari arms through a wrinkled blastula by holoblastic, radial cleavage. 2. About seven days after insemination, the posterior portion of the bipinnaria becomes swollen and fine spicules appear on it, while the anterior portion, the stalk, remains unchanged. 3. Metamorphosis takes place gradually at the posterior portion, while the metamorphosing bipinnaria is pelagic. Two weeks after insemination, the stalk rapidly shrinks and the larva sinks to the bottom. 4. About 18 days after insemination, the juvenile completes metamorphois with the opening of the mouth. The newly metamorphosed juvenile is 600 mu in diameter and each arm bears two pairs of the tube-feet, each having a sucker at the tip, and one terminal tentacle with red eye-spot. 5. The aboral skeletal system of the juvenile immediately after metamorphosis is composed of one central, one madreporic, ten radial and interradial plates, in addition to five terminal plates on the arms. 6. The juveniles smaller than about one cm in R do not bear some of the diagnostic features in this species. 7. A characteristic feature of the development of Astropecten, i.e., the lack of a brachiolaria stage, is stressed. The term "nonbrachiolarian type" is tentatively proposed to distinguish the development of Astropecten and Luidia, which do not pass through a brachiolaria stage, from the usual indirect type of development.

Animals↗