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941.
Summary Linear measurement of blocks of constitutive heterochromatin and the euchromatin portion 1q-h in three members of a family was used to study the dependence of the size of C blocks on the degree of chromosomal contraction. The results demonstrate that the size of heterochromatin portions decrease regularly with an increases of the degree of euchromatin contraction. The dependence was found to be linear, except for mitoses with an extremely high or low degree of contraction. The finding was used for the development of a new method of evaluation of constitutive heterochromatin. 相似文献
942.
Metabolism of benzo(a)pyrene by human lung microsomal fractions 总被引:2,自引:0,他引:2
The metabolism of benzo(a)pyrene was studied using microsomal fractions obtained from human lung derived at either resection or autopsy. The rates of metabolism and metabolite distribution were monitored using high pressure liquid chromatography and the metabolic rates were noted to be similar to those obtained using rat lung microsomes. In contrast to the rat, human lung microsomes appear to form a higher percentage of the 7,8-dihydro-7, 8-diol or 9,10-dihydro-9, 10-diol of benzo(a)pyrene as a fraction of the total metabolites. However, there was a significant variation among the human lung microsomal preparations which might reflect the clinical diagnosis and/or individual variation. 相似文献
943.
944.
Marden A. de Alvarenga Raimundo Braz Fo Otto R. Gottlieb João P. de P. Dias Aderbal F. Magalhães Eva G. Magalhães Gouvan C. de Magalhães Mauro T. Magalhães José G.S. Maia Raquel Marques Anita J. Marsaioli Antônio A.L. Mesquita Anselmo A. de Moraes Alaide B. de Oliveira Geovane G. de Oliveira Gentil Pedreira Sebastião K. Pereira Sonildes L.V. Pinho Celira C. Santos 《Phytochemistry》1978,17(3):511-516
Wood samples, infested by fungi during storage, were shown to contain, besides the known 5-methyl-mellein, additional (3R)-8-hydroxy-3-methyl-3,4-dihydroisocoumarins substituted by 7-methyl, 5-formyl, 5-carboxy, 5-hydroxy, 5-methoxy, 6-methoxy-5-methyl and 6,7-dimethoxy-5-methyl groups, as well as 6-formyl-7-hydroxy-5-methoxy-4-methylphthalide. Several 2-methylchromanones were synthesized in order to show that this class of compounds can be distinguished from 3-methyl-3,4-dihydroisocoumarins by MS. 相似文献
945.
Summary
Trifolium subterraneum, Trifolium glomeratum andOrnithopus compressus were grown in soil and solution culture at varying P concentrations. Efficiency of P utilization was determined using the
following criteria: (1) The ability to produce tops dry matter with a given amount of applied P, (2) Tops dry matter produced
per unit of P taken up, (3) Tops dry matter produced at a constant plant P level and (4) Phosphorus uptake per unit root weight.
The order of efficiency varied according to the crieteria used. Using the agronomic definition (1), Serradella was the most
efficient species at 70 days.
The need to clearly define what is meant by an efficient species is demonstrated. 相似文献
946.
Inhibitors from (Pinus pinea L.) seed coats were separated using paper chromatography, thin layer chromatography, and a Sephadex G-10 column. The inhibitory activity was resolved into several fractions. One of these behaved similarly to abscisic acid. It has exhibed the same properties as ABA in thin-layer chromatography, paper chromatography, and Sephadex G-10 chromatography and in UV absorption and fluorescence spectra. These germination inhibitors, present in the seed coats, are involved in the regulation of P. pinea seed germination.Abbreviations ABA
abscisic acid
- TLC
thin-layer chromatography 相似文献
947.
I Martín de Miranda J C Macome L E Costa A C Taquini 《Acta physiologica latino americana》1977,27(2):65-71
The role of the gonads and their hormones on body weight was studied in rats of both sexes submitted to chronic hypoxia and their controls at sea level atmospheric pressure. Intact rats were exposed to either 4 700 or 6 000 m simulated altitude in a hypopressure chamber. Castrated rats and castrated rats daily injected with either 0.5 mg of testosterone or 20 microgram of estradiol or the vehicle, were exposed to the higher altitude. The rat weight was recorded for a period of at least eight weeks. All groups of hypoxic male animals increased their weight significantly less than the controls at sea level. Also in castrated females and in castrated injected with testosterone or the vehicle the same pattern of weight curves was observed. On the contrary, groups of intact females and castrated females injected with estradiol did not show significant differences between hypoxic and control animals. Only in a group of smaller intact females (50-80 g) the body weight increase was significantly diminished by exposure to either 4 700 or 6 000 m simulated altitude. 相似文献
948.
Jan Jeník 《Folia Geobotanica》1977,12(2):208-208
949.
Bubeník J. Perlmann P. Indrová M. Šimová J. Jandlová T. Neuwirt J. 《Cancer immunology, immunotherapy : CII》1983,14(3):205-206
Summary Supernatants from Con A-stimulated rat spleen cell cultures containing T cell growth factor inhibited growth of a transplantable 3-methylcholanthrene-induced sarcoma in syngeneic mice. The tumour-inhibitory effects were dependent on the concentration of T cell growth factor and repeated injections of the supernatants. 相似文献
950.
Cyclopiazonic acid is a toxic metabolite of fungal origin that inhibits protein synthesis in intact HeLa cells and eukaryotic cell-free systems. It has been shown that cyclopiazonic acid blocks the GTP- and EF-1-dependent binding of (3H)Phe-tRNA to 80S ribosomes. Moreover the translocation of N-Ac-(3H)Phe-tRNA by 80S ribosomes that takes place in the presence of EF-2 and GTP is also halted by cyclopiazonic acid. It is concluded that this drug affects a ribosomal site involved in the alternative interaction of elongation factors EF-1 and EF-2. 相似文献