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Summary Apart from cancer and mutation induction, radiobiological effects on mammals are mostly attributable to cell death, defined as loss of proliferative capacity. Survival curves relate retention of that capacity to radiation dose, and often manifest a quasi-threshold (shoulder). The shoulder is attributable to an initial mechanism of repair (Q-repair) which is gradually depleted as dose increases. Another form of repair, which is not depleted (P-repair), increases the dose required to deliver an average of one lethal event per cell (dose D0). Neither form of repair can unambiguously be linked with repair of defects in isolated DNA. An important initial lesion may well be disruption of the complex structural relationship between the DNA, nuclear membrane and associated proteins. One form of P-repair may be restoration of that structural relationship. 相似文献
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Defensive steroids from a carrion beetle (Silpha americana) 总被引:2,自引:0,他引:2
J. Meinwald B. Roach K. Hicks D. Alsop T. Eisner 《Cellular and molecular life sciences : CMLS》1985,41(4):516-519
Summary The defensive anal effluent discharged bySilpha americana in response to disturbance contains a mixture of steroids stemming from a glandular annex of the rectum. The compounds have been characterized as 15-hydroxyprogesterone (1, principal component), 5-pregnan-15-ol-3, 20-dione (2), 5-pregnan-3, 15-diol-20-one (3), 5-pregnan-7, 15-diol-3,20-dione (4), 5-pregnan-3, 7, 15-triol-20-one (5), 5-pregnan-16-ol-3,20-dione (6), and 5-pregnan-3, 16-diol-20-one (7), none previously found in insects. Bioassays with jumping spiders showed compounds1 and6 to be feeding deterrents at the 1 g level.Paper No. 78 of the series: Defense Mechanisms of Arthropods. Study supported by NIH (Grants AI-02908, AI-12020). We thank Maura Malarcher and Maria Eisner for excellent technical help, and the Squibb Institute of Medical Research for samples of authentic reference compounds. 相似文献
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Citellus (s. str.) relictus, C. dauricus C. pygmaeus (2=36, NF=72). . (Colobotis) erythrogenys . fulvus -. . (Urocitellus) undulatus (2n=32, NF=64) . columbianus. Citellus, , Citellus, . , . 相似文献
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Zusammenfassung Die Synthese von 7-Hydroxy-5,6-dimethoxybenzofurano[3,2:3,4]coumarin aus 7,2-Dihydroxy-oder 7-Benzyloxy-2-hydroxy-4,5-dimethoxyisoflavon wird beschrieben. 相似文献
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C. F. Nadler R. S. Hoffmann A. Woolf 《Cellular and molecular life sciences : CMLS》1973,29(1):117-119
- . Ovis musimon (2n=54) O. orientalis (2n=54) - - -O. canadensis mexicana (2n=54) O. musimon x O. canadensis 12 - . 2 27 . - .
Supported by National Science Foundation Grant no. GB 32114X and the Sprague Foundation. We thank Dr. T. C. Hsu for assistance in making the chromosome preparations and for advice and encouragement. The Trustees of the Rachelwood Wildlife Research Preserve generously allowed the biopsy of specimens of their custody. Mr.Arthur Popham kindly provided the specimens from Iran while Dr.R. M. Robinson obtained biopsies from the desert sheep. 相似文献
Supported by National Science Foundation Grant no. GB 32114X and the Sprague Foundation. We thank Dr. T. C. Hsu for assistance in making the chromosome preparations and for advice and encouragement. The Trustees of the Rachelwood Wildlife Research Preserve generously allowed the biopsy of specimens of their custody. Mr.Arthur Popham kindly provided the specimens from Iran while Dr.R. M. Robinson obtained biopsies from the desert sheep. 相似文献
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Interaction of 1-anilino-8-naphthalene sulfonate with yeast glyceraldehyde-3-phosphate dehydrogenase
N. K. Nagradova R. A. Asryants M. V. Ivanov 《Cellular and molecular life sciences : CMLS》1971,27(10):1169-1170
1--8- () -3- () . []:[]<10:1 140 000 3±1 5×10–5
. , i 5×10–5
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G. N. Telesnina M. A. Novikova G. L. Zhdanov M. N. Kolosov M. M. Shemyakin 《Cellular and molecular life sciences : CMLS》1967,23(6):427-428
a aaa a aa aa a a E. coli aa, a aa aa a , a a aa - a .
Laboratory of Biological Investigations.
Laboratory for Chemistry of Antibiotics. 相似文献
Laboratory of Biological Investigations.
Laboratory for Chemistry of Antibiotics. 相似文献
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S. Bernasconi M. Ferrari P. Gariboldi M. Sisti G. Bolchi Serini M. Colombo 《Cellular and molecular life sciences : CMLS》1980,36(12):1337-1339
Summary Some compounds containing piperidine rings have been synthesized, and submitted to biological tests on insects for their hormonal activity on pupae ofTenebrio molitor L. andBombyx mori L. Some of them display a hormoneanalogue or toxic activity.The editors do not hold themselves responsible for the opinions expressed in the authors' brief reports. — Les auteurs sont seuls responsables des opinions exprimées dans ces brèves communications. — Für die Kurzmitteilungen ist ausschliesslich der Autor verantwortlich. — Per le brevi comunicazioni è responsabile solo l'autore. — . — Solo los autores son responsables de las opiniones expresadas en estas comunicationes breves.This research has been supported by the Italian National Research Council (CNR) special ad hoc program Fitofarmaci e Fitoregolatori, Subproject. 7.Acknowledgments. We thank Prof. G. Jommi for helpful discussions related to this and previous articles on the same subject. 相似文献
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I. A. Macdonald 《Cellular and molecular life sciences : CMLS》1978,34(4):426-427
Summary Tritium distribution on randomly labelled taurocholate (TC) was estimated at 28%, 4%, 1% and <0.5% on the hydrogens opposite the 3-, 7- and 12-OH groups and taurine moiety respectively. Anomalously,C. perfringens 3-hydroxysteroid dehydrogenase (3-HSDH) catalyzed tritium loss of 36% on formation of 7-, 12-dihydroxy-3-keto-5-cholanoate, implying additional losses of tritium at other sites by this enzyme.This work is supported by the National Cancer Institute. 相似文献
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G. Aranda A. Bervillé R. Cassini M. Fétizon B. Poiret 《Cellular and molecular life sciences : CMLS》1981,37(2):112-113
Summary Methomyl, or S-methyl-N [(methylcarbamoyl)oxy] thioacetimidate, a common insecticide, has been found to be a specific poison of mitochondria of corn with Texas cytoplasm. Its hydrolysis under very mild acidic conditions affords thiomethyl methylthiosulphonate, which strongly inhibits the activity of CmST and N mitochondria of corn. 相似文献
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R. I. Salganik S. V. Argutinskaya R. I. Bersimbaev 《Cellular and molecular life sciences : CMLS》1972,28(10):1190-1191
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F. Rollo W. Asci S. Antonini I. Marota M. Ubaldi 《Cellular and molecular life sciences : CMLS》1994,50(6):576-584
The paper reports on the molecular analysis of samples of approximately 5,300-year-old grass found at the alpine archaeological site where the so-called Tyrolean Iceman was discovered. The grass comes from a cloak made of long grass blades and/or the stuffing of the snow footwear worn by the Iceman. The results show that while the largest fraction of the DNA extractable from the grass is of foreign origin, a much smaller part belongs to the original genetic material of the grass itself, and can be used as a valuable taxonomic clue to the plant species utilized by neolithic men to manufacture their equipment. On the other hand, the foreign DNA, or at least a portion of it, comes from microorganisms-mainly filamentous fungi and unicellular algae-which seem to have been associated with the grass since the time the grass was harvested. 相似文献