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Biomedical subjects

S Fujimura

Publications and source records attributed to S Fujimura.

At least 379 records · Page 21Linked to original sources
PubMed1982

Interaction of N-ethyl-N'-nitro-n-nitrosoguanidine with nucleic acids and proteins in comparison with N-methyl-N'-nitro-N-nitrosoguanidine.

Reactivity of N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) was studied in comparison with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). The radioactivity of [guanidino-14C]-ENNG was incorporated only into the protein fraction and that of [ethyl-14C]ENNG was incorporated into DNA, RNA and protein fractions in ascites hepatoma AH7974 cells, as were those of [guanidino-14C]- and [methyl-14C]MNNG, respectively. The amounts of the binding of ENNG were less than those of MNNG, especially in the corporation of the ethyl moiety of ENNG into nucleic acid fractions. In a non-cellular system, the radioactivity of [guanidino-14C]ENNG was incorporated into proteins, preferentially into basic proteins such as cytochrome c, but was not incorporated into nucleic acids. This behavior is similar to that of [guanidino-14C]MNNG, while the amount of binding of the former was about half of that of the latter. The radioactivity of [ethyl-14C]ENNG was also incorporated into basic proteins to almost the same extent as that of [methyl-14C]MNNG. However, the binding of the ethyl moiety of ENNG to nucleic acids was much lower than that of the methyl moiety of MNNG. Horse heart cytochrome c, bovine pancreatic RNase A and regenerating rat liver chromatin had altered their biological activities to various degrees after modification by ENNG or MNNG.

Animals↗
PubMed1982

Tumor promoters increase the synthesis of a 32,000-dalton protein in BALB/c 3T3 cells.

The effect of 12-O-tetradecanoylphorbol 13-acetate (TPA), a potent tumor promoter, on the synthesis of proteins in BALB/c 3T3 mouse fibroblasts has been studied. When [35S]methionine-labeled proteins synthesized after the addition of TPA were analyzed by one- or two-dimensional polyacrylamide gel electrophoresis, the increased synthesis of a 32,000-dalton protein (designated p32) was noted as one of the earliest changes. The synthesis of p32 increased approximately 2-fold within 2 hr at a promoter concentration of 20 ng/ml. Phorbol 12,13-didecanoate, another potent tumor promoter, showed the same effect as TPA, whereas 4-O-methyl-TPA, which has little promoting activity, did not enhance the synthesis of p32 at the same concentration but did effect a slight increase at 1 microgram/ml. p32 differed immunologically from a major excreted protein discovered by Gottesman [Gottesman, M. M. (1978) Proc. Natl. Acad. Sci. USA 75, 2767-2771]. The increased rate of the synthesis of p32 was considered to be regulated at the transcriptional level, because the increase in synthesis of p32 was inhibited by actinomycin D, and TPA-treated cells were shown to contain a higher level of translatable mRNA coding for p32 than do control cells. A possible relationship between the increase in p32 synthesis and transformation is discussed.

Animals↗
PubMed1982

Induction of morphological differentiation in cultured mouse neuroblastoma cells by alkylating agents.

A series of N-alkyl-N-nitrosoureas, which produce both alkylation and carbamoylation, was found to induce neurite formation in mouse neuroblastoma N-18 cells just as does N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Related compounds, which produce only carbamoylation or nitroguanidination, did not induce morphological differentiation, while methyl methanesulfonate (MMS) and dimethyl sulfate, which produce only alkylation, did. MNNG, methyl nitrosourea and MMS were more effective in the induction of differentiation than their corresponding ethyl derivatives. These data suggested that alkylation contributed to the induction of morphological differentiation in N-18 cells.

Alkylating Agents↗
PubMed1982

Hemolysin of Propionibacterium avidum.

Thiol-activated extracellular hemolysin produced by a strain of Propionibacterium avidum was partially purified and several properties were examined. The hemolysin was heat labile and inactivated by proteases and deoxyribonuclease. Hemolysin adsorbed to erythrocytes at 0 degrees C. Cu++ at 1 mM inhibited hemolysis partially. Lecithin prevented the activity completely. The hemolytic spectrum was relatively wide and the activity was high with rabbit, dog, horse, and pig erythrocytes.

Animals↗
PubMed1981

Absence of gamma-actin expression in the mouse fibroblast cell line, L.

Cytoplasmic isoactins of mouse fibroblast L-cells were examined by two-dimensional gel electrophoresis. In contrast to other cultured cell lines, which contain both beta- and gamma-actin, L-cells contained only beta-actin species. This unique phenomenon was due neither to the transformed status of this cell line nor to the characteristic nature of adipose tissue fibroblasts of C3H mice. When RNA of L-cells was translated in a nuclease-treated reticulocyte lysate system, actin synthesized in vitro also appeared as only one species, beta-actin. Therefore, the genetic information for gamma-actin is absent at the level of translatable mRNA in L-cells.

Actins↗
PubMed1981

Bacteriocin-like substance (melaninocin) from oral Bacteroides melaninogenicus.

A bacteriocin-like substance, designated melaninocin, was extracted from a strain of Bacteroides melaninogenicus by ultrasonic treatment and purified. Melaninocin was heat labile and was destroyed by digestion by several proteolytic enzymes. Among the oral indigenous microorganisms, Bacteroides, Actinomyces, and streptococci were found to be sensitive to melaninocin.

Amino Acids↗
PubMed1981

Isolation and characterization of proteases from Bacteroides melaninogenicus.

We isolated two types of intracellular proteases from a strain of Bacteroides melaninogenicus. These enzymes were extracted from cells by ultrasonic treatment and were partially purified. These two enzymes (proteases I and II) differed in molecular weight, heat stability, sensitivity to reducing agents, Km value, and optimum pH for activity.

Bacteroides↗