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171.
172.
Phytochrome Control of Its Own Synthesis in Pisum sativum 总被引:1,自引:0,他引:1
Otto Veit; Sch?fer Eberhard; Nagatani Akira; Yamamoto Kotaro T.; Furuya Masaki 《Plant & cell physiology》1984,25(8):1579-1584
An analysis of phytochrome synthesis in Pisum seedlings by measuringthe activity of polysomal polyadenylated RNA (poly-A+-RNA) codingfor phytochrome apoprotein showed phytochrome control of itsown synthesis; brief red-light irradiation of pea seedlingsinhibited the activity of the RNA, and the red-light effectwas red/far-red reversible.
4 Permanent address: Biology Department, Faculty of Science,University of Tokyo, Hongo, Tokyo 113, Japan. (Received August 13, 1984; Accepted September 17, 1984) 相似文献
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Summary Paternal age distribution for 1279 cases of Down's syndrome born in 1952–1968 was compared with the corresponding distribution for the general population, corrected for the maternal age as well as for the year of birth of the patients. Although there was no difference in the mean paternal age, the two distributions differed significantly, largely due to the excess of fathers aged 55 years and over and to the deficit of those aged 40–44 years in the patients born to mothers aged 30 years and over. The overall pattern of the relative incidence of Down's syndrome with advancing paternal age, with maternal age controlled, seems consistent with the hypothesis proposed by Stene et al. (1977). It increased from 0.8 for fathers aged 20–24 years slowly up to 1.2 for those aged 45–49 years, though with an intermediate drop to 0.8 at the age of 40–44 years, and then sharply to 2.4 for those aged 55 years and over. This rising pattern of the relative incidence with paternal age was essentially the same for the patients born in 1952–1960 and for those born in 1961–1968, although the slope was less steep in the latter than in the former group.This paper is dedicated to Professor Heinrich Schade in honor of his 70th birthday 相似文献
175.
Requirement of Cyclic Adenosine 3′,5′-Monophosphate for the Thermosensitive Effects of Rts1 in a Cyclic Adenosine 3′,5′-Monophosphate-Less Mutant of Escherichia coli
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Previous publications showed that a covalently closed circular (CCC) Rts1 plasmid deoxyribonucleic acid (DNA) that confers kanamycin resistance upon the host bacteria inhibits host growth at 42 degrees C but not at 32 degrees C. At 42 degrees C, the CCC Rts1 DNA is not formed, and cells without plasmids emerge. To investigate the possible role of cyclic adenosine 3',5'-monophosphate (cAMP) in the action of Rts1 on host bacteria, Rts1 was placed in an Escherichia coli mutant (CA7902) that lacks adenylate cyclase or in E. coli PP47 (a mutant lacking cAMP receptor protein). Rts1 did not exert the thermosensitive effect on these cells, and CCC Rts1 DNA was formed even at 42 degrees C. Upon addition of cAMP to E. coli CA7902(Rts1), cell growth and formation of CCC Rts1 DNA were inhibited at 42 degrees C. The addition of cAMP to E. coli PP47(Rts1) did not cause inhibitory effects on either cell growth or CCC Rts1 DNA formation at 42 degrees C. The inhibitory effect of cAMP on E. coli CA7902(Rts1) is specific to this cyclic nucleotide, and other cyclic nucleotides such as cyclic guanosine 3',5'-monophosphate did not have the effect. For this inhibitory effect, cells have to be preincubated with cAMP; the presence of cAMP at the time of CCC Rts1 DNA formation is not enough for the inhibitory effect. If the cells are preincubated with cAMP, one can remove cAMP during the [(3)H]thymidine pulse and still observe its inhibitory effect on the formation of CCC Rts1 DNA. The presence of chloramphenicol during this preincubation period abolished the inhibitory effect of cAMP. These observations suggest that cAMP is necessary to induce synthesis of a protein that inhibits CCC Rts1 DNA formation and cell growth at 42 degrees C. 相似文献
176.
Summary The transepithelial resistance, the cell membrane resistance and the ratio of resistances of the serosal (baso-lateral) to the mucosal (brush border) cell membrane were measured in rat duodenum, jejunum and ileum by means of microelectrode techniques. These measured values were not affected in the presence of actively transported solutes in the mucosal bathing fluid.Contribution of an electrical conductance through the extracellular shunt pathway to the total transepithelial conductance was quantitatively estimated using an electrically equivalent circuit analysis. These values estimated in respective tissues of small intestine were approx. 95% of the total transepithelial conductance, remaining unaffected by an active solute transport.From these data, the changes in emf's of the mucosal and serosal membrane induced byd-glucose or glycine were separately evaluated. 相似文献
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178.
Noyes' scheme of the elementary processes for the Belousov-Zhabotinsky reaction has been simplified on the basis of reaction kinetic consideration. The simplest possible analogue (model K) has been described by a set of kinetic equations, and it is solved to examine the varieties of new ordered phases, which include temporal rhythm and spatial pattern. Particular attention has been given to the onset of new phases, which is associated with an anomalous enhancement of fluctuations. A stochastic theory of fluctuations, which was developed in our previous work, has been applied to the present case. Theoretical results compare reasonably well with experimental findings, i.e. with (1) spatial periodic structure and (2) limit cycle behaviour. 相似文献
179.
Takamichi Ichinose Akira K. Suzuki Hirokazu Tsubone Masaru Sagai 《Life sciences》1982,31(18):1963-1972
Strain differences of mice in their susceptibility to nitrogen dioxide (NO2) were examined by measuring the activities of antioxidative protective enzymes, and the amounts of antioxidants and lipid peroxides in lungs. Four strains of mice: ICR, BALB/c, ddy and C57BL/6 were used in this study and their LC50 values after exposure to NO2 for 16 hr were: 38, 49, 51 and 64 ppm, respectively (1).Genetic strain differences were observed in the enzyme activities, the antioxidant contents and lipid peroxide contents among these four different strains. The activities of glutathione peroxidase (GPx), glutathione S-transferase, and superoxide dismutase (SOD), and the contents of non-protein sulfhydryls (NPSH), α-tocopherol (α-Toc) and total lipids in lungs of the four strains were related to their LC50, while TBA reactants in lungs of the four strains were inversely related to their LC50.After exposure to 20 ppm NO2 for 16 hr, the activities of the protective enzymes and the contents of NPSH decreased, while the level of α-Toc increased markedly. The activities of GPx, 6-phosphogluconate dehydrogenase, SOD and disulfide reductase, and the contents of NPSH, α-Toc and total lipids were also related to their LC50. On the other hand, TBA reactants increased higher than those of the control groups and were inversely related to their LC50.These results suggest that the protective enzymes and the antioxidants are important factors as defence mechanism in lungs to NO2 and that the intensity of the protective systems in pigmented strains is generally greater than that in albino strains. 相似文献
180.
Yoshihide Yamasaki Osamu Shimamura Akira Kizu Masao Nakagawa Hamao Ijichi 《Life sciences》1982,31(5):471-478
The formaldehyde method was used to examine the interaction of PGE1 with morphine, β-endorphin and Met-enkephalin on rat mast cells by their effects on IgE-mediated 14C-serotonin release. PGE1 (2×10?8?2×10?5 M) caused a dose-related inhibition of the mediator release 1 min after an antigen challenge, and morphine (3×10?7?3×10?5 M) reversed this PGE1 effect dose-dependently and stereospecifically; naloxone (2×10?4 M) antagonized this action of morphine. β-Endorphin (3×10?7?10?5 M) and Met-enkephalin (3×10?6?10?4 M) mimicked this morphine action dose-dependently and were antagonized by naloxone (2×10?4 M). These results suggest that morphine and endorphins modulate immunological mediator release from rat mast cells through opioid receptors. 相似文献