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A. R. Tébar V. M. Fernández R. MartinDelRío A. O. Ballesteros 《Cellular and molecular life sciences : CMLS》1973,29(12):1477-1479
Resumen Se han realizado estudios de asociación-disociación por filtración en gel con el primer enzima de la biosíntesis de histidina enEscherichia coli, en presencia de sustratos y ligandos. Se observa una interconversión reversible entre las formas dímero, tetrámero y exámero, y una agregación irreversible de orden superior. 相似文献
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A. Borovanský L. Beneš L. Kopáčová J. Čižmárik 《Cellular and molecular life sciences : CMLS》1968,24(4):376-377
Summary Highly active local anaesthetics from the group of basic substituted cyclohexylesters of 2-chloro-, 2, 6-dichloro-, 2-chloro-6-methyl-, 2-methyl-, 2, 6-dimethyl-and 2,4,6-trimethylcarbanilic acid were developed. The substances were tested for local anaesthetic activity in surface anaesthesia. 相似文献
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Eight types of bisalbuminaemia 总被引:3,自引:0,他引:3
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The homeotic protein AGAMOUS controls microsporogenesis by regulation of SPOROCYTELESS 总被引:1,自引:0,他引:1
Ito T Wellmer F Yu H Das P Ito N Alves-Ferreira M Riechmann JL Meyerowitz EM 《Nature》2004,430(6997):356-360
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Senescence may result from an optimal balance between current reproductive investment and bodily repair processes required for future reproduction, a theoretical prediction difficult to prove especially in large, long-lived animals. Here we propose that teeth that have fixed dimensions early in life, but that wear during chewing, can be taken as a measure of total lifetime 'repair', and their wear rate as a measure of current expenditure in performance. Our approach also considers the sexual selection process to investigate the advance of senescence in males compared with females, when selection favouring competition over mates reduces the reproductive lifespan of males. We studied carcasses of 2,141 male and 739 female red deer (Cervus elaphus) of different ages, finding that male molariform teeth emerged at a far smaller size than expected from body size dimorphism. This led to higher workload, steeper wear rate and earlier depletion of male teeth than in females, in concordance with sex-specific patterns of lifetime performance and reproduction. These findings provide the empirical support for the disposable-soma hypothesis of senescence, which predicts that investment in bodily repair will decrease when the return from this investment may not be realized as a result of other causes that limit survival or reproduction. 相似文献
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Rusznák Z Pocsai K Kovács I Pór A Pál B Bíró T Szücs G 《Cellular and molecular life sciences : CMLS》2004,61(12):1532-1542
In this work, the distributions of some acid-sensitive two-pore-domain K+ channels (TASK-1, TASK-2 and TASK-3) were investigated in the rat and human cerebellum. Astrocytes situated in rat cerebellar tissue sections were positive for TASK-2 channels. Purkinje cells were strongly stained and granule cells and astrocytes were moderately positive for TASK-3. Astrocytes isolated from the hippocampus, cerebellum and cochlear nucleus expressed TASK channels in a primary tissue culture. Our results suggest that TASK channel expression may be significant in the endoplasmic reticulum of the astrocytes. The human cerebellum showed weak TASK-2 immunolabelling. The pia mater, astrocytes, Purkinje and granule cells demonstrated strong TASK-1 and TASK-3 positivities. The TASK-3 labelling was stronger in general, but it was particularly intense in the Purkinje cells and pia mater.Received 25 February 2004; received after revision 19 April 2004; accepted 28 April 2004 相似文献