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31.
Summary Acid phosphatase activity in the hemolymph and cuticle was higher during the early part of the fifth instar than at any other time. The enzyme activity in the fat body, testes, salivary glands, and midgut was statistically the same throughout the instar.Acknowledgment. This research was supported in part by NSF grant GB 26542-Al to D. F. 相似文献
32.
R. L. Lindsay Dorothy Chase K. A. Dasse D. J. Burke A. H. Goldberg W. C. Ullrick 《Cellular and molecular life sciences : CMLS》1981,37(12):1297-1298
Summary Mechanical evidence is presented to show that fast muscle tissue regenerating in the bed of a slow muscle, and innervated by the slow muscle nerve, has contractile properties identical to those of a slow muscle regenerating in its own bed. The results do not support the idea that regenerating fast muscles are partially resistant to the transforming effects of a slow nerve.This investigation was supported in part by NIH grants 1-RO1-NS-14033 and 1-T32-07224. 相似文献
33.
Karen Bush Joan S. Freudenberger Dorothy S. Slusarchyk R. B. Sykes E. Meyers 《Cellular and molecular life sciences : CMLS》1982,38(4):436-437
Summary Growth ofCandida albicans can be inhibited by sulfa drugs which prevent biosynthesis of folic acid. The dihydrofolate reductase (E.C. 1.5.1.3) inhibitors aminopterin and methotrexate also exhibit anticandidal activity, but trimethoprim does not. Kinetic evaluations withC. albicans dihydrofolate reductase indicate that methotrexate and aminopterin are tight-binding inhibitors whereas trimethoprim binds poorly. 相似文献
34.
The strength of the Earth's early geomagnetic field is of importance for understanding the evolution of the Earth's deep interior, surface environment and atmosphere. Palaeomagnetic and palaeointensity data from rocks formed near the boundary of the Proterozoic and Archaean eons, some 2.5 Gyr ago, show many hallmarks of the more recent geomagnetic field. Reversals are recorded, palaeosecular variation data indicate a dipole-dominated morphology and available palaeointensity values are similar to those from younger rocks. The picture before 2.8 Gyr ago is much less clear. Rocks of the Archaean Kaapvaal craton (South Africa) are among the best-preserved, but even they have experienced low-grade metamorphism. The variable acquisition of later magnetizations by these rocks is therefore expected, precluding use of conventional palaeointensity methods. Silicate crystals from igneous rocks, however, can contain minute magnetic inclusions capable of preserving Archaean-age magnetizations. Here we use a CO2 laser heating approach and direct-current SQUID magnetometer measurements to obtain palaeodirections and intensities from single silicate crystals that host magnetite inclusions. We find 3.2-Gyr-old field strengths that are within 50 per cent of the present-day value, indicating that a viable magnetosphere sheltered the early Earth's atmosphere from solar wind erosion. 相似文献