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Zusammenfassung Bei Farnvorkeimen (Dryopteris filix-mas) steigert Blaulicht spezifisch DNS-Replikation und mitotische Aktivität, so daß sich die im Hellrot bzw. Blaulicht herangewachsenen Vorkeime, die gleichviel Trockensubstanz besitzen, bezüglich ihres DNS-Gehalts und ihrer Zellzahl wesentlich unterscheiden — Die Zelle scheint als Bezugssystem für RNS, Protein und entsprechende biochemische Größen ungeeignet zu sein. Der Gesamtkeimling ist das angemessene Bezugssystem.
The regulation of DNA synthesis in fern gametophytes by light
Summary In young gametophytes (= sporelings) of the common male fern (Dryopteris filix-mas) short wavelength light (= blue light) specifically increases DNA replication and mitotic activity even if the sporelings have the same growth rate under blue and red light, as determined by dry matter increase. Cell number and DNA content of sporelings of the same age and the same dry matter content are much higher under blue than under red light (Figs. 1, 2). In the second part of the paper it is pointed out that the cell (or unit of DNA) may not be used as a system of reference for biochemical data such as protein or RNA content in the case of the fern sporelings (and possibly not in many other organisms either). The appropriate system of reference seems to be the entire multicellular system if precaution is taken that the systems grow with the same growth rate under the different experimental conditions (e.g. under blue and red light in the case of the fern sporelings).相似文献
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Helga Rehder Wiltrud Coerdt Reinhard Eggers Franz Klink Eberhard Schwinger 《Human genetics》1989,82(4):377-385
Summary A retrospective study of 200 missed abortions was performed to determine whether morphological criteria alone are sufficient to ascertain a chromosomal aetiology. Placental changes were clasified into five morphological and four morphometric groups, according to the severity of alterations, and were then correlated with the cytogenetic data. The rate of chromosome anomalies was approximately 50% and was thus not significantly different within the groups II–V, but it was 80% in group I, which covered the most severe placental alterations, namely the partial hydatidiform moles. There was a high incidence of triploidies in group I, trisomies with obligatory early lethality in groups II and III, and X-monosomies in group III. Our findings do not support previous evidence regarding the specificity of certain villous alterations in association with chromosome aberrations. Indeed, they indicate that the placental villi may react similarly to chromosomal and nonchromosomal disturbances and that placental morphology depends on the severity and the temporal onset of the underlying disorder rather than on its type. With respect to chorionic villus samplings (CVS), this would mean that an abnormal villous structure may be suggestive for a chromosome anomaly but does not exclude a normal karyotype.Dedicated to Professor Marlis Tolksdorf on the occasion of her 65th birthday 相似文献
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Nikolett Mihala Jzsef Bdi gnes Gmry Helga Süli‐Vargha 《Journal of peptide science》2001,7(10):565-568
The success of solid phase peptide synthesis is often limited by the aggregation of the growing peptide chains on the resin. Working from the results of a study of model coupling reactions in solution between Z-Gly-Phe-OH and H-Phe-OBzl, we have achieved higher efficiency in the repetitive solid phase fragment condensation of VGVAPG, in a 3:1 chloroform-phenol solvent system, using diisopropylcarbodiimide (DIC) as coupling agent, and a combination of 3-hydroxy-3,4-dihydro-4-oxo-1,2,3-benzotriazine (HODhbt) and its tetrabutyl ammonium salt as additive, than in DMF with DIC and HODhbt alone. 相似文献