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51.
52.
The urinary excretion of C21- and C19-steroids was investigated in female babons (Papio hamadryas) treated with the ovulation inhibitor Ovosiston (mestranol + chlormadinone-acetate), in comparison with an untreated control Group Urinary C21-steroid excretion was not significantly altered by Ovosiston. 17-Ketosteroids were decreased, predominantly 11-oxygenated compounds. 相似文献
53.
Detection and Identification of Translocations by Increased Specific Nondisjunction in ASPERGILLUS NIDULANS 总被引:4,自引:3,他引:1 下载免费PDF全文
A meiotic technique for visual detection of translocations has been applied to ten mitotically identified interchanges, and three new translocations were discovered using this method. Testcrosses between "standard" strains and potential translocation strains-e.g. strains with newly induced mutants or descendants from translocation crosses-are inspected for the frequency of abnormal-looking colonies. In all heterozygous translocation crosses "abnormals" are increased at least tenfold compared to the average control level of 0.15%. Most of these are disomics, and can be recognized by their characteristic phenotypes. Each translocation produces a few specific types, since nondisjunction is increased mainly in the linkage groups involved in the translocation (50-100-fold over control values). Therefore, translocations were not only detected but often tentatively assigned to linkage groups from the analysis of the disomic progeny in crosses. In addition, this technique allows reciprocal and nonreciprocal translocations to be distinguished, since only the latter produce one-third phenotypically abnormal duplication progeny. While results are clearcut in most cases, occasionally problems are encountered, e.g. when morphological mutants segregate in crosses, or when other genetic factors which increase or reduce the frequency of nondisjunction are present in certain strains. 相似文献
54.
Zusammenfassung Inaktive Riesenchromosomen der Speicheldrüsen ausgewachsener Chironomus thummi-Larven zeigten nach 60 min Inkubation mit 0,05 N Putrescin-, Spermidin-oder Spermin-Lösung erneute Syntheseaktivitäten, die sich im Einbau von radioaktiv markiertem Uridin autoradiographisch zu erkennen geben. Diese Beobachtung wird im Zusammenhang mit der bekannten genaktivierenden Wirkung von Mg++ diskutiert. Auf der Basis zahlreicher biochemisch analoger Wirkungen von Polyaminen und Mg++ wird ein ursprünglich für die genaktivierende Wirkung von Mg++ postuliertes Modell auf Polyamine übertragen.
Stimulation of gene activities by polyamines an autoradiographic study with giant chromosomes of Chironomus thummi
Summary Inactive salivary gland giant chromosomes of full grown Chironomus thummi larvae showed after 60 min of incubation in 0.05 N putrescine, spermidine or spermine solutions autoradiographically demonstrable incorporation of radioactiv labelled uridine caused by a reactivation of RNA synthesis. This observations is discussed in relation to the known gene activating effect of Mg++, and, since polyamines and Mg++ have numerous effects in common, it is suggested that polyamines affect gene activity in a way similar to Mg++.相似文献
55.
56.
Dr. Konrad Märkel 《Zoomorphology》1969,66(1):1-50
Structure and growth of a keeled tooth are discussed with Paracentrotus lividus as the main example. The microscopic structure of the tooth skeletons of other sea urchins was compared, considering at least one member of each family with the exception of Saleniidae. Attention is called to the necessary revision of the system of sea urchins.
Mit Unterstützung durch die Deutsche Forschungsgemeinschaft. 相似文献
Mit Unterstützung durch die Deutsche Forschungsgemeinschaft. 相似文献
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58.
Hagemann Joh Buder Ramshorn I. Grebenščikov J. Schöneich Alfred Lein F. Fabig G. Tembrock A. J. Müller 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1964,34(5):229-232
Ohne Zusammenfassung 相似文献
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60.
Lubomír Scháněl 《Biologia Plantarum》1966,8(4):292-298
Mycelium of white-rot fungi secretes laccase into the medium. It was found by cultivation on malt-agar plates that the mycelium does not produce laccase equally in all its parts. The youngest hyphae at the margins of the colony represent usually the maximum producers, whereas older hyphae produce less or none at all. An exception here isCollybia velutipes which is the weakest producer of laccase of all the fungi studied and where only the older hyphae begin to secrete it. Manometric estimation of laccase showed that maximum specific activity of laccase is achieved at the boundary between the phases of initial and linear growth and i11 some cases during the first half of linear growth. Ageing of the mycelium characterized by certain changes in its metabolism is reflected in changes of enzyme production by fungal hypha of different age. 相似文献