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1.
Although phorbol 12-myristate 13-acetate (PMA) inhibits apoptosis and promotes the growth of some types of cells, it induces apoptosis in other cells. We evaluated the apoptotic effects of PMA on murine fibroblasts (L-929) that had been exposed to ultraviolet-B (UV-B) radiation at 312 nm, which promotes tumor cell growth. Exposure to PMA alone did not induce Fas, Fas-L, or apoptosis. Cells exposed to mild UV-B irradiation (80 J/m(2)) alone exhibited a slight expression of Fas and Fas-L 36 to 48 h after the exposure, and exhibited apoptosis as evidenced by DNA fragmentation 72 h after exposure. The addition of PMA (0.8 x 10(-5) to 3.2 x 10(-5) M) to the medium 24 h after the UV-B exposure markedly and dose-dependently enhanced these cell responses. Confluent untreated cells, cells cocultured with PMA, and cells cocultured with PMA for 24 h after the UV-B exposure consistently expressed mRNAs for wild-type p53, bcl-2, and ICE. Expression of c-myc mRNA was initially observed, but became undetectable in the cells cocultured for 24 h with a high concentration of PMA (3.2 x 10(-5) M) following UV-B exposure. Such cells subsequently exhibited the maximal apoptotic response. We conclude that mild exposure to UV-B altered murine fibroblast cells in such a way as to facilitate their death by apoptosis upon addition of PMA. 相似文献
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Sixteen enzymatic and non-enzymatic proteins of the pigeon Columba livia domestica were examined electrophoretically. These proteins were presumed to be under control by 22 loci. Of the 22 loci, 6 were defined as polymorphic and 15 as monomorphic. Another locus was variable, but the variation was not genetically interpretable. Average heterozygosity calculated over 21 loci was 0.075. 相似文献
4.
Ono Mayumi Kuwano Michihiko Mizushima Shoji 《Molecular genetics and genomics : MGG》1979,170(1):11-23
Molecular Genetics and Genomics - Ribosomal protein S1 from a newly isolated Escherichia coli mutant has a molecular weight of about 54,000 which is smaller than the wild type S1 (M.W. 65,000). The... 相似文献
5.
S Shoji J Ohnishi T Funakoshi K Fukunaga E Miyamoto H Ueki Y Kubota 《Journal of biochemistry》1987,102(5):1113-1120
The phosphorylation sites of myelin basic protein from bovine brain were determined after phosphorylation with Ca2+-calmodulin-dependent protein kinase. Four phosphorylated peptides were selectively and rapidly separated by reversed-phase high-performance liquid chromatography. Partial sequencing of the phosphorylated peptides by automated Edman degradation revealed that Ca2+-calmodulin-dependent protein kinase phosphorylated serine-16, serine-70, and threonine-95 specifically, as well as serine-115, which is located on the experimental allergic encephalitogenic determinant of the protein. Of the four amino acid sequences determined, two sequences surrounding phosphorylated amino acids, -Lys-Tyr-Leu-Ala-Ser(P)16-Ala- and -Arg-Phe-Ser(P)115-Trp-Gly-, have both sides of each phosphoserine residue occupied by hydrophobic amino acids, and a basic amino acid, arginine or lysine, is located at the position 2 or 4 residues amino-terminal to the phosphoserine residue. In contrast, the two other sequences surrounding phosphorylated amino acids, -Tyr-Gly-Ser(P)70-Leu-Pro-Glu-Lys- and -Ile-Val-Thr(P)95-Pro-Arg-, have a basic amino acid at the position 2 or 4 residues carboxyl-terminal to the phosphoamino acid residue. 相似文献
6.
The interaction of the specific sugar residue in ginsenosides with egg phosphatidylcholine vesicles was investigated by ESR spectrometry using phosphatidic acid spin-labeled at the polar head groups. Ginsenoside-Rc, which has an alpha-L-arabinofuranose residue and agglutinability toward egg yolk phosphatidylcholine vesicles (Fukuda, K. et al. (1985) Biochim. Biophys. Acta 820, 199-206), caused the restriction of the segmental motion of spin-labeled phosphatidic acid in egg phosphatidylcholine vesicles, indicating that the saponin interacted with the polar head groups of vesicles. Other ginsenosides-Rb2, Rb1, Rd and p-nitrophenyl glycoside derivatives which have less or no agglutinability were also investigated in the same manner. Only ginsenoside-Rb2 and p-nitrophenyl alpha-L-arabinofuranoside which have the specific sugar residue (arabinose) showed a strong interaction with the polar head groups of vesicles. To gain an insight into the mechanism of agglutination by ginsenoside-Rc, the interaction with the fatty acyl groups was also studied by using phosphatidylcholine spin-labeled at the fatty acyl groups. Ginsenoside-Rc increased the order parameter of the spin-labeled phosphatidylcholine, indicating that the saponin was inserted into lipid bilayers. In other saponins investigated, only ginsenoside-Rb2 interacted with the fatty acyl part of vesicles. The process of expression of agglutination by ginsenoside-Rc was discussed on the basis of the ESR studies. 相似文献
7.
Liver glutathione S-transferase polymorphism in Japanese and its pharmacogenetic importance 总被引:1,自引:1,他引:0
Shoji Harada Masato Abei Naomi Tanaka Dharam P. Agarwal H. Werner Goedde 《Human genetics》1987,75(4):322-325
Summary A total of 168 autopsy liver extracts from Japanese individuals were examined for the glutathione S-transferase (GST) isozymes by means of starch gel electrophoresis. The gene frequencies of GST1*1, GST1*2, and GST1*0 in Japanese were 0.252, 0.057, and 0.691, respectively. GST1*3 was detected as a rare variant allele. The incidence of GST1 0 in 41 liver biopsy samples from patients suffering from various liver diseases was investigated using polyacrylamide gel isoelectric focusing. The GST1 0 phenotype was found more frequently in livers with hepatitis and carcinoma than in control livers. The isozymes coded by different GST loci were partially purified and characterized to study their biochemical properties. The apparent Km values with 1-chloro-2,4-dinitrobenzene (CDNB) as substrate for the isozymes at the GST1, GST2, GST3, and GST4 loci were 604, 1345, 776 and 591 M, respectively. 相似文献
8.
Summary A growth associated formation of extracellular 5-aminolevulinic acid (ALA) was found in the homoacetogenesis of glucose byClostridium
thermoaceticum grown in minimal defined medium. The growth and ALA production was enhanced by L-cysteine HCl both in complex medium (UM) and minimal defined medium (MDM). The amount of ALA produced extracellularly in MDM wasca. 15 mg/L after 90-h anaerobic cultivation (cell-mass: 1.5 g/l; glucose consumed: 20 g/l). 相似文献
9.
Kenzo Yamanaka Akira Hasegawa Ryoji Sawamura Shoji Okada 《Biological trace element research》1989,21(1):413-417
DNA damage induced by administration of dimethylarsinic acid (DMAA) to rats and mice was investigated. At 12 h after administration of DMAA, DNA single-strand breaks were induced markedly in lung. The majority of dimethylarsine, one of the main metabolites, in the expired air was excreted within 6–18 h after administration of DMAA to rats. In vitro experiments using nuclei isolated from lung of mice indicated that DNA strand breaks were caused by dimethylarsine. Furthermore, the strand breaks after exposure to dimethylarsine were reduced in the presence of catalase and/or superoxide dismutase. These results strongly suggest that the strand breaks are induced not by dimethylarsine itself but by active oxygen, e.g., O 2 ? and ·OH, produced both by dimethylarsine and molecular oxygen. When DNA was exposed to dimethylarsine, thiobarbituric acid (TBA)-reactive intermediates andcis-thymine glycol were produced. Dimethylarsine appears to induce DNA damage by the mechanism similar to the damage produced by ionizing radiation. 相似文献
10.