An electron-microscopic study on lipogenesis

With the purpose to elucidate morphologically the site where fat synthesis takes place in the cell, electron-microscopic observation has been conducted on the interscapular brown fat tissue of mice at various periods of carbohydrate introduction after starvation. By starving mice, the depot lipids in the brown fat have been discharged almost completely, and the carbohydrate introduction has caused the biosynthesis of lipids from carbohydrtates in the same tissue. Observations on the tissues proved that the lipogenesis in the brown fat tissue cells takes place in the ground substance keeping the intimate correlation with the endoplasmic reticulum but not in the mitochondria.</p

Mitochondria and Endoplasmic Reticulum in the Denucleated Red Cells, with Special Reference to the Reticulum of Reticu-locyte

In 1955 SANO found mitochondria by the supravital stain with Janus green B in the basophilic stippled cells from the circulating blood of the lead intoxicated rabbitsl , and in 1956 by means of electronmicroscope VALLEJO-FREIRE, BRUNNER et al. found mitochondria in the reticulocytes2,3, and later at the end of 1956 BRAUNSTEINER et al. also succeeded in revealing mitochondria and the vesicular structure by electron microscope in the ultra thin section of young red cells4. We also have found the mitochondria and the endoplasmic reticulum in young red cells. It has been discussed long whether the reticulum of reticulocytes is a preexistent structure or an artifact. The fact that the mitochondria exist in the reticulocyte seems to support strongly the preexistence theory of the reticulum, substantia reticulo filamentosa. However, the fact that the reticulum has several characteristics different from the general mitochondria5,6 can not be ignored. In this paper we should like to demonstrate the photos of mitochondria and the endoplasmic reticulum in the denucleated red cells revealed by electron microscope comparing to the picture of reticuluocyte appeared by supravital stain.</p

Cytochemical studies of the hemoglobin synthesis of erythroblasts

The process of hemoglobin sythesis in erythroid cells have been traced mainly by observing cells under the light of 4,060 &#197;. To scrutinize the theory of hemoglobin synthesis in the nucleus of erythroblasts, several cytochemical and morphological observations were also carried out. The conclusions derived from them are as follows: 1 The absorption at 4,060 &#197; of the cell, which indicates the location of heme, appeared in the nucleus as early as in the develpmental stage of basophilic erythroblasts. The absorption of hcme in cytoplasm likewise appeared in this stage showing nearly the same intensity of the absorption. The absorption picture of heme in the nucleus, which is coincidental with that of interchromatin, increased along with the progess of maturation as well as in the cytoplasm. The absorption in the nucleus disappeared at the orthochromatic stage where the picture of interchromatin disappeared, while the intensity of absorption in the cytoplasm continued to increase till the stage of reticulocyte. 2 The pseudoperoxidase reaction of hemoglobin, the appearance of acidophlic protein and masked lipids detectable in the location of hemoglobin gave an exactly identical picture with that of the absorption of heme in the nucleus as well as in the cytoplasm. 3 Permeability test performed by supravital staining with Nile blue revealed that the nucleus of erythroblasts from the basophilic to the orthorchromatic stages has increased its permeability being stained selectively as in the case of dead cells. 4 The mitochondria and the endoplasmic reticulum proved to be retained well in the entire course of hemoglobin synthesis, even after the denucleation, the reticulocyte stage. From these observations the authors believe that the hemoglobin syntheis will take place in the cytoplasm throughout the life cycle of erythroid cells, pointing out that the absorption picturebf heme appearing in the nucleus will be in all likelihood due to the infusion of the hemoglobin from the cytoplasm.</p