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151.
M-phase and S-phase protoplasts were prepared from tobacco cells in suspension culture after a high degree of synchronization using aphidicolin, a specific inhibitor for eukaryotic DNA polymerase. When TMV-RNA was introduced into these protoplasts mediated by REV liposomes, 37% of M-phase and 26% of S-phase protoplasts were infected as determined by the fluorescent antibody technique. After the 24 hr interval between the introduction of TMV-RNA into protoplasts and the determination of infection, half of the infected mitotic protoplasts formed dumbell-shaped daughter cells. The significance of synchronized protoplasts in genetic engineering of plant cells is discussed in reference to the delivery of DNA into the nucleus.Abbreviation LS
medium, Linsmaier and Skoog medium
- PEG
polyethylene glycol
- REV
reversephase evaporation vesicles
- TMV
tobacco mosaic virus 相似文献
152.
The mode of chromosome segregation in an asymmetrically dividing bacterium, Caulobacter crescentus, was studied by examining the fate of labeled DNA strands. Swarmer cells (one type of Caulobacter daughter cell), in which single strands of DNA had been labeled with [3H]thymidine during the previous round of chromosome replication, were grown synchronously in a non-radioactive medium for two generations. The distribution of radioactivity among the cells was visualized by autoradiography under a phase-contrast microscope. The labeled DNA strands in each cell were found to consist of two conserved units. From this, we propose a model in which the swarmer cell has two identical chromosomes, which are segregated into the progeny swarmer cell and the progeny stalked cell after chromosome replication. 相似文献
153.
Shinkichi Kamata Akira Okada Takehiko Watanabe Yasunaru Kawashima Hiroshi Wada 《Journal of neurochemistry》1980,35(5):1190-1199
The etiologic relationship between disturbances in metabolism of amino acids and amines and hepatic coma was investigated by examining the effects of diets containing various mixtures of amino acids on brain amine metabolism in rats with a portacaval shunt, using a method for simultaneous analysis of amino acids and amines. Rats with a portacaval shunt were fed on four different amino acid compositions with increased amounts of various amino acids suspected to be etiologically related to hepatic coma, such as methionine, phenylalanine, tyrosine, and tryptophan. The animals were killed 4 weeks after operation. During the experimental period, these animals did not become comatose, but exhibited various behavioral abnormalities. Marked increase in the plasma and brain levels of the augmented amino acids, especially methionine and tyrosine, were observed in rats with a portacaval shunt. Brain noradrenaline, dopamine, and serotonin levels were significantly decreased when the brain tyrosine level was increased. These results indicate that in rats with a portacaval shunt the dietary levels of amino acids greatly influence the brain levels of both amino acids and transmitter amines. 相似文献
154.
Radioisotopically labelled l-leucine and l-valine were fed to Pisum sativum and incorporated into squalene and β-amyrin. Chemical degradation of the radioactive squalene revealed an equal distribution of the radioactivity in the isopentenyl pyrophosphate(IPP)-derived and the 3,3-dimethylallyl pyrophosphate(DMAPP)-derived moieties of the squalene molecule, unlike the unbalanced distribution in favour of the DMAPP-derived moiety of a monoterpenoid molecule biosynthesized from these amino acids by higher plants. 相似文献
155.
Hideki Shinno Chiseko Noda Keiji Tanaka Akira Ichihara 《Biochimica et Biophysica Acta (BBA)/General Subjects》1980,633(3)
L-Lysine-2-oxoglutarate reductase (EC 1.5.1.8, NADP+) in the liver of adult rats increased 4–5-times when the animals were treated with alloxan. In diabetic rats injection of insulin or adrenalectomy prevented the increase in enzyme activity. The activity of the similar enzyme in kidney was not changed by these treatments. The enzyme activity in primary cultured adult rat hepatocytes was also induced by addition of dexamethasone and glucagon together, and glucagon could be replaced by dibutyryl cyclic AMP. Insulin inhibited the induction. The hormonal induction was also inhibited by actinomycin D and by cycloheximide. During development of rats, fetal liver showed very low activity, but the activity appeared on day 1 after birth and then increased rapidly, reaching the adult level by day 5. The activity of the kidney enzyme increased more slowly and reached the adult level 1 month after birth. Intra-uterine injection of glucagon caused precocious induction of the liver enzyme in fetuses. These results indicate that the activity of L-lysine-2-oxoglutarate reductase in the adult liver and in part in neonatal liver also, is controlled by both glucagon and glucocorticoid. 相似文献
156.
157.
Biosynthesis of glycerol teichoic acid in Bacillus cereus: formation of linkage unit disaccharide on a lipid intermediate 总被引:5,自引:0,他引:5
N Murazumi Y Sasaki J Okada Y Araki E Ito 《Biochemical and biophysical research communications》1981,99(2):504-510
A tunicamycin-like antibiotic 24010 at a concentration of 1 μg/ml selectively inhibited the synthesis of glycerol teichoic acid of cell walls in AHU 1030. Incubation of membranes of this strain with -acetylglucosaminyl pyrophosphorylundecaprenol and UDP--acetylmannosamine led to formation of a glycolipid having a saccharide moiety identical with the cell wall teichoic acid linkage unit, -acetylmannosaminylβ(1→4)--acetylglucosamine. The membranes also catalyzed transfer of glycerol phosphate units from CDP-glycerol to this disaccharide-linked lipid. Thus the biosynthesis of the cell wall glycerol teichoic acid in this strain seems to involve the disaccharide-linked lipid as an intermediate. 相似文献
158.
Shoichi Fujita Yoshiie Okada Jack Peisach 《Biochemical and biophysical research communications》1981,102(1):492-498
Hepatic microsomal azoreductase activity in mice was induced with phenobarbital (PB) and 3-methylcholanthrene (3-MC). Antibodies against cytochrome P-450 inhibited azoreductase activity of PB-treated animals while antibodies against cytochrome P-448 inhibited liver azoreductase activity of 3-MC-treated animals, each by about 90%. These antibodies also inhibited microsomal 7-ethoxycoumarin-O-deethylase activity to the same extent. It is concluded that hepatic microsomal azoreductase activity is almost totally dependent on cytochromes P-450 and P-448 and the contribution, if any, of other microsomal components is negligible. 相似文献
159.
Masatoshi Takeichi Tadao Atsumi Chikako Yoshida Kazuko Uno T.S. Okada 《Developmental biology》1981,87(2):340-350
The specificity of adhesion between embryonal carcinoma cells and fibroblastic cells of various origins was studied. Embryonal carcinoma cells have intercellular adhesion sites requiring Ca2+ (CDS). These sites were found to be sensitive to proteases but resistant to them in the presence of Ca2+. CDS with a similar protease sensitivity is present in fibroblastic cells. When embryonal carcinoma cells of different lines were mixed, they adhered to each other nonselectively by CDS. Nonselective adhesion by CDS occurred also between fibroblastic cells of various lines. When embryonal carcinoma and fibroblastic cells were mixed, they preferentially adhered to homotypic cells. Fab fragments of antibodies raised against F9 cells (a nullipotent line of embryonal carcinoma) inhibited the adhesion between embryonal carcinoma cells but not between fibroblastic cells. This inhibitory activity of Fab was absorbed with embryonal carcinoma cells with CDS, but not with fibroblastic cells with CDS or embryonal carcinoma cells from which CDS was experimentally removed. SDS-polyacrylamide gel electrophoresis of radioiodinated cell surface proteins showed that the presence of a 140K-dalton component correlated with the presence of CDS in embryonal carcinoma cells, while the presence of a 150K-dalton component correlated with the presence of CDS in fibroblastic cells. These results suggest that CDS in embryonal carcinoma and fibroblastic cells comprise distinct molecules. 相似文献
160.