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941.
The kinin system of human plasma. V. The probable derivation of prekallikrein activator from activated Hageman factor (XIIa) 总被引:9,自引:0,他引:9
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Summary The incorporation of C14-amino acids (aspartic acid, glutamic acid, threonine and proline) and C14-nucleic acid bases (adenine, guanine, cytosine and uracil) into the seedling, reproductive stage and young ear portion of
rice plant was investigated.
It was found that C14-aspartic acid was incorporated into the rice seedling more rapidly than C14-threonine or C14-proline; on the other hand C14-proline was found to be more rapidly incorporated than C14-aspartic acid into reproductive stage plant and young ear portion.
Similarly C14-adenine was incorporated into the rice seedling more rapidly than other C14-labelled bases. On the other hand C14-uracil was preferentially incorporated to C14-adenine or C14-guanine into the reproductive stage plant and young ear portion.
It is suggested from the results obtained that proline is polymerized into polypeptide or protein in the rice plant more rapidly
at the reproductive stage than at the seedling stage and that a higher proportion of pyrimidine bases might be involved into
the metabolic process at the reproductive stage of rice plant. 相似文献
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D Keglevi? B Ladesi? O Hadzija J Tomasi? Z Valinger M Pokorny R Naumski 《European journal of biochemistry》1974,42(2):389-400
950.
Mechanical properties of isolated living muscle spindles from Xenopus laevis were examined in order to determine their role in sensory transduction. The reticular zone of the intrafusal muscle fibers was identified microscopically by: (1) its position beneath the sensory endings, (2) its length, 50–100 μm, (3) its extension during intrafusal muscle contraction, and (4) its coarse striations with a period of about 1.5 times the normal sarcomere length. The reticular zone in the passive muscle spindle did not extend until the spindle was stretched to about 1.05–1.1 its maximal length in the animal (L m ). Evidence was obtained that the absence of extension of the reticular zone at normal muscle lengths was due to the presence of the spindle capsule which acted as a stiff element in parallel with the sensory region. At those lengths at which the reticular zone did extend (> L m ), no rate — sensitive mechanical properties were detected in response to step and ramp extensions. The sensory discharge of the spindle showed no dynamic transient in response to ramp extensions if the reticular zone were not extended. During extension of the reticular zone a dynamic sensory transient appeared. It is concluded that current notions on the mechanical origin of the rate — sensitive properties of the sensory discharge of the muscle spindle do not apply to Xenopus laevis. In addition, it is not likely that the passive spindle in this animal is a sensitive stretch receptor. 相似文献