Fusako Mitsuhashi

Angioarchitectural structure of the fungiform papillae on rabbit tongue anterodorsal surface

The relationships between the functional and morphological characteristics and the positional difference of the microvascular cast specimen (MVCS) of the fungiform papillae (FuP) on the antero-dorsal surface of the rabbit tongue were examined and compared using a scanning electron microscope (SEM). The sporadic FuPs scattered among the numerous small filiform papillae (SfP) were found to be distributed irregularly over the antero-dorsal surface. FuPs consisted of the ascending and descending capillary loops, forming margins of the central opening at the top of FuP. They resembled flower-like configurations (carnations), the petals of which ranged from eight to twelve, and they were larger in width and more complex in shape than SfPs with morphological differences. FuPs can be classified into three types: type I (consisting of eight petals), type II (ten petals), type III (twelve petals) according to the shape of FuP, and to the petal number of the flower-like aspect on the eight points of MVCS of FuPs observed by SEM. These results suggest that the petals of the ascending and descending capillary loops of FuP expanded the flower-like figure, increased in the surface areas and effectively play a role in receiving the sense of taste.

SEX-SPECIFIC CELL SURFACE STRUCTURE OF ANISOGAMETES: MORPHOLOGICAL CHANGES DURING FERTILIZATION OF BRYOPSIS MAXIMA (ULVOPHYCEAE, CHLOROPHYTA) REVEALED BY ULTRA–HIGH-RESOLUTION FIELD EMISSION SEM1

Cell surfaces of biflagellate gametes and their morphological changes during fertilization of Bryopsis maxima Okamura were observed using a high‐resolution field emission scanning electron microscope. Male gametes have broad and narrow faces, which are divided into at least five morphologically distinct regions: 1) the apical plate is a plate‐like structure that is approximately 380–530 nm long and approximately 190 nm wide, in the center of the papilla and slightly protruded from the plasma membrane; 2) strips are smooth materials on ridges that originate from the basal part of the papilla and extend downward; 3) the lateral belt is a belt‐shaped structure on the center of the narrower faces; 4) the flagellar surface; and 5) the other region of the cell body has a fine‐grained appearance. In contrast, the entire female gamete surface is rough because of many granular or amorphous cell coats on the plasma membrane. When both gametes were mixed together, the initial fusion proceeded between the broader face of the male gamete and the anterior side of the female one near the basal bodies. Morphology of the male gametes cell surface changed gradually as fusion proceeded and was covered by the granular materials; that surface closely resembled those of female gametes except for the apical plate. It was present until the planozygote attached itself to the substrate by the papilla. It finally disappeared after settlement. Therefore, these results indicate that gametes of B. maxima have sex‐specific surface structures that change their morphology during fertilization and settlement.

Angioarchitectural form, functional distributive pattern and classification of the fungiform papillae on the crossbred Japanese cat tongue anterodorsal surface in scanning electron microscopic specimens

The purpose of this study was to undertake a three-dimensional comparative observation of the angioarchitectural form, functional distributive pattern and classification of the filiform papillae (FiP) as they appear on the entire dorsal surface of the front of the Japanese cat tongue using microvascular cast specimens (MVCS). By means of the corrosive resin casting technique, the MVSC of the FiP of the cat tongue were prepared and examined in detail under the scanning electron microscope (SEM). On the frontal half of the anterodorsal surface of the anterior tongue, types I-V of the FiP are arranged in the form of a A with the point in the direction of the apex and in an oblique line running from the antero-central to both postero-peripheral regions. In the rear half of the anterodorsal surface of the anterior part of the tongue, types I-V of the FiP are arranged in the form of a V with the point in the direction of the root and in an oblique line running from both antero-peripheral regions to the postero-median region or towards the pharynx on the anterior centro-dorsal surface of the tongue. The FiP, arranged in an oblique line running fron the central to the apical part of both the periphery and the pharyngeal region of the cat tongue, can be classified into five types (Types I-V) according to the shape and size of the main process (MP), numbers of the accessory processes (AP) and regional position of the lozenge arrangement. FiP Types I-III consisted of an MP which contained a large spoon-shaped and concave network process, and the AP contained a bundle of spin-like processes arranged radially at the anterior basal margin of the MP. FiP Types IV and V consisted only of MP. It was conjectured that the lozenge arrangement of the A and V form FiPs, classified into five types (Types I-V) from the frontal portion of the anterodorsal surface toward the pharynx on the front of the tongue, play a functionally assistant role in the mastication of food and sucking of liquid, including milk.

Contribution of phosphoglucosamine mutase to determination of bacterial cell morphology in Streptococcus gordonii

Phosphoglucosamine mutase (GlmM; EC 5.4.2.10) catalyzes the interconversion of glucosamine-6-phosphate to glucosamine-1-phosphate, an essential step in the biosynthetic pathway leading to the formation of the peptidoglycan precursor uridine 5′-diphospho-N-acetylglucosamine. We have recently identified the gene (glmM) encoding the enzyme of Streptococcus gordonii, an early colonizer on the human tooth and an important cause of infective endocarditis, and indicated that the glmM mutation in S. gordonii appears to influence bacterial cell growth, morphology, and sensitivity to penicillins. Moreover, the glmM mutation results in increased sensitivity to polymorphonuclear leukocyte (PMN)-dependent killing. In the present study, we observed similarities in the utilization of sugar between the wild-type strain and the glmM mutant of S. gordonii when cultivated with medium containing 0.2% glucose, fructose, lactose, or sucrose. Morphological analyses clearly indicated that the glmM mutation causes marked elongation of the streptococcal chains, enlargement of bacterial cells, increased distortion of the bacterial cell surface, and defects in cell separation. These results suggest that mutations in glmM appear to influence bacterial cell growth and morphology, independent of the carbon source.

Classification of angioarchitectural structures of the rabbit tongue foliate papillae in scanning electron microscopic specimens

Although may ultrastructural morphological studies have been undertaken on the lingual papillae of the rabbit tongue, relatively few have dealt with the microvascular structure and classification of the foliate papillae (FoP) in microvascular cast specimens (MVCS) by means of scanning electron microscopy (SEM). For the present study, a three-dimensional observation and classification was carried out by SEM. The morphological characteristics of the outer frame structure composed of the ascending and descending capillary branches, were observed by means of MVCS of FoPs which were located on both posteroperipheral parts of the tongue. They showed a bead-like appearance and consisted of 14∼18 even, transverse and slightly bent fin-like structures, running from the dorsal surface to both peripheral sides symmetrically.FoPs could be classified into two types: typical or manely symmetrical and atypical or manely asymmetrical. The typical type was subdivided into three types: type I was symmetrically made up of 14 fins, type II of 16 fins, type III of 18 fins. The atypical type was subdivided into two subtypes: type IV was asymmetrically made up of 14 fins (left side) and 16 fins (right side), type V of 18 fins (left side) and 16 fins (right side). Half of the 65 cases were type II (50.8%), consisting of 16 fin-like microvascular structures, and there were no sex and age differences found.These are fin-like microvascular structures seen to increas on the surface areas and to play a functional role in sensing taste.

Isoproterenol Protects the Demilune Cells of the Sublingual Gland of Mice from Radiation : Study of Autoradiography with ^3H-leucine

Abstract In order to examine the influence of X-ray irradiation on the demilune cells of the sublingual gland due to the existence of secretory granules, 10 Gy of X-ray irradiation was applied to the sublingual gland of mice at 3 hours after isoproterenol (IPR) administration. To inspect the influence of irradiation at 3 days after the irradiation, tissue images and results of autoradiography performed at 30 and 120 minutes (min) after 3 H-leucine administration of the IPR administration (IPR/10Gy) group were compared with those of the non-IPR administration (nonIPR/10Gy) group. In transmission electron microscope images, swelling and pyknosis were observed in the rough endoplasmic reticulum of the nonIPR/10Gy group. The number of reduced silver grains per unit cell area in nonIPR/10Gy at 30 and 120 min after 3 H-leucine administration was less and greater than that in the other 3 groups (nonIPR/0Gy, IPR/0Gy, and IPR/10Gy), respectively, from light microscope autoradiography images. At 120 min after 3 H-leucine administration, the ratio of the number of reduced silver grains localized in the secretory granules to the total number of reduced silver grains in the demilune cells of the nonIPR/10Gy group was lower than that of the other 3 groups as indicated by electron microscope autoradiography images. Based on these results, it was apparent that the effect of irradiation was less on the demilune cells that discharged secretory granules than those that did not discharge them.