Studies on the relation between heme and nucleic acid syntheses in erythroid cell. II. Nucleic acid synthesis in erythroblast of anemic rat treated with aminopterin and bromouracil

With the bone marrow of anemic rats, which had received the repeated injections of phenylhydrazine once a day for three to four days, the effects of aminopterin and bromouracil on the nucleic acid metabolism of erythroblasts were observed in vivo experiment. The injection of aminopterin suppressed DNA synthesis with the lowered labeling index as observed by the incorporation of &#179;H-thymidine into DNA in vitro. But the grain count per cell showed the level similar to that of anemic control. RNA synthesis was not interfered by AP injections. These results indicate that AP mainly suppresses the thymidilate kinase. Bromouracil showed no such effect even on the administration of a large dose. On the basis of the data obtained from the experiment by using AP, a discussion was made on the correlation between DNA synthesis, nuclear function and the cell specialization.</p

Studies on the relation between heme and nucleic acid syntheses in erythroid cell. 3. Nucleolus of erythroblast, changes in relation with cell specialization

The disappearance of nucleolus has been traced in the rat erythroid cells in relation with the cell specialization under varying conditions, i. e. in anemia with or without treatment by bromouracil and aminopterin. To make the findings more reliable the observations have been made on tissue section as well as on the smeared samples as the nucleolus becomes often indistinct in smeared cell. The results indicate that under anemic condition nucleolus is lost by the late basoplilic stage. Treatment with bromouracil retained the nucleoli and cytoplasmic basophilicity till later stage of cell specialization suggesting some similar mechanism of RNA disintegration both in nucleolus and cytoplasm.</p

Rotational Symmetry and A Light Mode in Two-Dimensional Staggered Fermions

To obtain a light mode in two-dimensional staggered fermions, we introduce four new local operators keeping the rotational invariance for a staggered Dirac operator. To split masses of tastes, three cases are considered. The mass matrix and the propagator for free theories are analyzed. We find that one of three cases is a good candidate for taking a single mode by the mass splitting. In the case, it is possible that a heavy mode obtains infinite mass on even sites or odd sites.Comment: 17 pages, one reference adde

Studies on Regioselective Binding Mode of Steroid Molecules in Homology Modeled Cytochrome P450-2C11

In this study, we investigated the regioselective binding mode of steroid molecules and structure requirements for steroid molecules for 16[alpha]-hydroxylation by Cytochrome P450-2C11. Docking study by using the homology Cytochrome P450-2C11 indicated that 16[alpha]-hydroxylation is favored with steroidal molecules possessing the following components, 1) a bent A-B ring configuration (5[beta]-reduced), 2) C-3[alpha]-hydroxyl group, 3) C-17[beta]-acetyl group, and 4) methyl group at both the C-18 and C-19. These respective steroid components requirements such as A-B ring configuration and functional groups at C-3 and C-17 were defined as the inhibitory contribution factor. Overall results by rat CYP2C11 revealed that steroidal structure requirements resulted in causing an effective inhibition of [^3^H]progesterone 16[alpha]-hydroxylation by the adult male rat liver microsome. As far as docking of homology modeled CYP2C11 against investigated steroids is concerned, they are docked at the active site superimposed with flurbiprofen. It was also found that the distance between heme iron and C16[alpha]-H was between 4 to 6 &#xc5; and that the related angle was in the range of 180&#xb1;45&#xb0;

Studies on the relation between heme and nucleic acid syntheses in erythroid cell. I. Effects of aminopterin and bromouracil on hemopoiesis and hemoglobin synthesis in anemic rat

For the purpose to see how the suppression of the nucleic acid synthesis disturbs the cell specialization process the author observed the erythroid cell specialization in anemic rats by treating them with aminopterin (AP) and 5-bromouracil (BU). The observations indicate that the AP injection inhibits the mitosis of erythroblast with the acceleration of hemoglobin synthesis and the denucleation. The bromouracil administration scarcely suppressed the mitosis and the appearance of acidophilicity of erythroblast was retarded. Data indicate that the inhibition of mitosis accelerates the specialization or somatic protein synthesis of erythroblast. The acting mechanisms of the medicaments were discussed from the characteristics of these agents as the analogue of the substances related to DNA metabolism.</p