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91.
Growth regulators were measured in extracts from the upper and lower halves of 7-mm apical segments of horizontally oriented, red-light-irradiated and non-irradiated roots of Zea mays L. cv. Golden Cross Bantam 70 which exhibit a georesponse only after an exposure to light. Abscisic acid (ABA) was measured by gas-liquid chromatography, auxin (indole-3-acetic acid, IAA) by the Avena straight-growth assay, and an unidentified growth inhibitor by a Zea root-growth assay. The ratio of ABA in the upper and lower halves was 1.6 in the irradiated roots and 1.0 in the non-irradiated ones. The total amount of ABA after irradiation was increased by a factor of ca. 1.8. The ratio of IAA in the upper and lower halves of irradiated and non-irradiated roots was 1:3.4 and 1:2.9, respectively. The content (or activity) of an unidentified growth inhibitor was highest in the lower halves of horizontally oriented roots which had been irradiated with red light. The unidentified growth inhibitor, rather than IAA or ABA, may be the major factor in the light-induced geotropic responsiveness in Zea roots. 相似文献
92.
Effects of GA3 and CCC application on the sprouting of bulbilsor subterranean dormant organs of 10 species in the genus Dioscoreawere observed. Although the efficiency of both chemicals differedby species, in general GA3 inhibited and CCC promoted the sproutingof the above dormant organs. In some species, however, dilutedGA3 (0.0030.3 µM) has a promotive and diluted CCC(330 µM) has an inhibitive effect on sprouting. Effects of GA3 application on shoot elongation were tested onsprouted bulbils. GA3 promoted elongation when applied directlyto the shoots and inhibited it when applied to the bulbous parts. These results suggest that GA activates two opposing reactionssprouting-promotingand sprouting-inhibitingin these organs. The complicatedrelation between GA3 or CCC concentrations and sprouting wereexplainable by assuming that the two counteractive reactionswere activated by GA in different degrees.
1 Present address: Department of Biology, Faculty of Science,Yamagata University, Yamagata 990, Japan. (Received June 21, 1976; ) 相似文献
93.
Y Tanigawa A Kitamura M Kawamura M Shimoyama K Fujii Y Kohri I Ueda 《Physiological chemistry and physics》1978,10(5):443-448
Administration of prednisolone and cholate to rats elevated levels of cAMP (adenosine 3',5'-cyclic monophosphate) by 1.5- to 2.0-fold. Compounds such as prednisolone, hydrocortisone, cholate, and deoxycholate were found to be potent inhibitors of partially purified cAMP phosphodiesterase prepared from rat liver. Kinetic analysis showed that the prednisolone inhibition was noncompetitive with a Ki of 8.9 x 10(-4) M. These results suggest that in addition to increasing DNA-dependent RNA polymerase activity in vivo, a large application of glucocorticoid may incur elevation of intracellular cAMP levels. 相似文献
94.
The increase in the dichroism of the ester-C=O and COObands in response to mechanical extension in oat coleoptilecell walls was much enhanced by IAA pretreatment while the decreasein that of the C-O-C band was not enhanced or even suppressed.The results indicate the importance of the ultrastructure ofnon-cellulosic polysaccharides in controlling auxin-inducedcell elongation.
1 Present adress: Department of Agricultural Chemistry, KyotoPrefectural University, Shimogamo, Kyoto 606, Japan. (Received May 16, 1978; ) 相似文献
95.
Takehiko Watanabe Yoshitaka Taguchi Yukihiko Kitamura Kenichiro Tsuyama Hirota Fujiki Hiroshi Tanooka Takashi Sugimura 《Biochemical and biophysical research communications》1982,109(2):478-485
The effects of various promoters in two-step carcinogenesis on the induction of histidine decarboxylase in the skin of mice was investigated. The potencies of various phorbol esters in inducing histidine decarboxylase activity were parallel with their tumor-promoting activities. Indole alkaloids such as dihydroteleocidin B and lyngbyatoxin A, which induced ornithine decarboxylase and promoted tumor development in the skin of mice with the same potency as 12-O-tetradecanoylphorbol-13-acetate (TPA), also induced histidine decarboxylase activity. These results suggest that histamine produced by this inducible histidine decarboxylase may play some role in tumor promotion. 相似文献
96.
K Kitamura Y Mizuno A Sasaki A Yasui S Tsuiki K Kikuchi 《Journal of biochemistry》1991,109(2):307-310
A cDNA clone containing the full coding sequence of a type 1 protein phosphatase catalytic subunit 1 alpha has been isolated from a rat kidney lambda gt 10 library. The protein sequence deduced from the cDNA contains 330 amino acid residues with a molecular mass of 38 kDa. The cDNA clone from rat kidney was 89% identical at the nucleotide level in the coding region to type 1 protein phosphatase 1 alpha from rabbit skeletal muscle. However, the two protein sequences were completely identical. The type 1 alpha protein phosphatase from rat kidney shows 49% homology of amino acid sequence to the rat type 2A alpha protein phosphatase. Thus, the protein sequence of type 1 alpha protein phosphatase was completely conserved between rat and rabbit. The mRNA levels of type 1 protein phosphatase were determined in rat liver, AH13, a strain of rat hepatoma, and regenerating rat liver by Northern blot analysis using the cDNA fragment as a probe, under which conditions a single mRNA of 1.5 kb was detected. The mRNA levels of AH13 were remarkably increased when compared to those of normal ivers, whereas the mRNA levels of regenerating livers were slightly but significantly increased. These results demonstrate a marked increase in gene expression of type 1 protein phosphatase in hepatoma cells, suggesting an important role of the type 1 protein phosphatase in hepatocarcinogenesis. 相似文献
97.
98.
Expression of major myelin glycoprotein P0 by P0 cDNA transfection into C6 glioma cells promoted homophilic cell adhesion of the cells. After the dissociated cells were incubated for various times, the number of particles at each time point was measured. The total number of particles decreased to 24% in 60 min for transformant (C6P0) cells, in contrast to only 68% for control (C6P0') cells. To confirm the homophilic mechanism of adhesion, mixed-cell aggregation experiments were performed. Among the four synthetic peptides corresponding to a part of the P0 sequence used, only peptide 3 (residues 90-96), which contained a carbohydrate attaching site, caused considerable inhibition of cell aggregation (approximately 50%). In addition, the glycopeptide (residues 91-95) obtained from bovine P0 markedly inhibited cell aggregation (by approximately 85%). 相似文献
99.
A Yamamoto T Kaji K Tomoo T Ishida M Inoue M Murata K Kitamura 《Journal of molecular biology》1992,227(3):942-944
Cathepsin B from bovine spleen has been purified and crystallized as a complex with a specific inhibitor CA074 [N-(L-3-trans-propylcarbamoyloxirane-2-carbonyl)-L- isoleucyl-L-proline], using the hanging-drop method. The complex crystals obtained from 50 mM-citrate buffer (pH 3.5) belong to the tetragonal space group P4(1) (or P4(3)) with a = 73.06 A and c = 141.59 A, and diffract beyond 2.2 A resolution. There are two complex molecules per asymmetric unit giving a packing density of 3.37 A3/Da and indicating a high solvent content of 63.5%. 相似文献
100.
A Naito Y Kitamura H Yoshikura 《Biochemical and biophysical research communications》1991,174(1):305-312
Relative orientation of recombination substrates, neo gene, strongly influenced homologous recombination events in a bovine papillomavirus shuttle vector. Between direct repeats, recombination occurred at a high frequency while between inverted repeats, it was rare. Double strand break near the mutation site increased the recombination frequency between inverted repeats but not between direct repeats. Formation of long heteroduplex as a recombination intermediate may explain this apparently paradoxical phenomenon. 相似文献