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141.
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P A Benn 《Cytogenetics and cell genetics》1977,19(2-3):118-135
Common chromosome break points were found in a banding study of 25 chromosomally abnormal fibroblast clones derived from normal individuals and patients exposed to environmental carcinogens. Of 81 break points, 38% appeared to be in terminal bands. This specificity did not appear to be the consequence of the biased recognition of exchanges. In addition, specificities for break points at exact interstitial loci were detected. The presence of clones in cultures grown in a wide variety of conditions, the finding of two identical clones in two independent lines from the same biopsy, and the absence of any obvious continuing instability in lines support the view that chromosomally abnormal fibroblasts occur in vivo. 相似文献
143.
Thirty-five individuals aged 17 to 24 in whom severe chronic hyperactivity had been diagnosed 10 years before were studied together with 25 matched controls. There were no significant differences in mean height or weight or in electroencephalographic findings, but the mean pulse rate was significantly higher in the hyperactive group. Cognitive style tests indicated continued difficulty in reflection (resulting in more errors) but less impulsivity (longer reaction time) in the hyperactive individuals. Compared with controls, hyperactive subjects were continuing to have more scholastic difficulty, although this difference seemed to be less pronounced than 5 years before. Their adjustment in work situations and living arrangements did not differ significantly from that of the controls. Restlessness, both reported and observed, continued to be a problem for the hyperactive individuals, and socialization skills and sense of well-being continued to be poorer than in the controls. The hyperactive individuals did not show significantly more antisocial behaviour, nonmedical use of drugs or serious psychiatric disturbances. 相似文献
144.
M. Bennàsar I. Cáceres G. Cuenca-Bescós R. Huguet H.A. Blain J. Rofes 《Historical Biology》2017,29(2):248-252
The discovery of small, very well-defined and perfectly preserved tooth marks on the humerus of a mole, Talpa cf. europaea (TE9, Sima del Elefante, Sierra de Atapuerca, Burgos), is extraordinary. To date, no micromammal fossil is known with puncture prints produced by a bite with a clear or delimited morphology that would permit its detailed study. The exceptional character of the finding may raise questions and suspicions about alteration and taphonomic agents. However, we have evidence that both the marks in the mole humerus are due to the action of biting and that this bite corresponds to the dentition of Beremendia fissidens. After all, not only large predators bite, as this article intends to demonstrate. 相似文献
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M.H. Benn Anita Lencucha Susan Maxie S.A. Telang 《Journal of insect physiology》1973,19(11):2173-2176
Methacrylic and ethacrylic acids were found to be the major organic components of the pygidial defensive secretion of Carabus taedatus. Valine was converted to methacrylic acid by the beetle. 相似文献
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Hybridization arrest of cell-free translation of the malarial dihydrofolate reductase/thymidylate synthase mRNA by anti-sense oligodeoxyribonucleotides. 总被引:2,自引:1,他引:1 下载免费PDF全文
In order to inhibit the in vitro translation of Plasmodium falciparum mRNA coding for the bifunctional enzyme dihydrofolate reductase-thymidylate synthase (DHFR-TS), oligodeoxynucleotides (ODNs) were directed against the translation initiation site or a site in the TS-coding region. In both cases considerable hybridization arrest, i.e. greater than 50% inhibition, was only achieved if the lengths of the ODNs to the two regions were 30 and 39 nucleotides, respectively, or longer. The ODN with the highest efficiency was a 49-mer directed against the TS-coding region (OTS49); 45 microM was sufficient to inhibit the expression of DHFR-TS by almost 90%. In this case the synthesis of DHFR-TS was interrupted at the binding site of OTS49 by a RNase H-independent mechanism. The resulting polypeptide was smaller (55 kDa) than one subunit of the native protein (71 kDa) and lacked TS activity. 相似文献