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51.
Summary Exposure of green peach aphids,Myzus persicae (Sulz.), to an atmosphere containing mercury vapor resulted in a curtailment ofembryogenesis and larviposition by adults, and in the development by larvae and adults of a cuticular darkening of their legs, head capsule, antennae, cornicles and cauda. Mortality of affected larvae resulted from molting difficulties, particularly by last-instar alatiform female and male larvae. Greenbugs,Schizaphis graminum (Rond.), and pea aphids,Acyrthosiphon pisum (Harr.), responded to mercury vapor exposure in similar ways. 相似文献
52.
R. P. Botham D. J. Beadle R. J. Hart C. Potter R. G. Wilson 《Cellular and molecular life sciences : CMLS》1978,34(2):209-210
Summary Excitatory terminals, depleted of their synaptic vesicles by stimulation at high frequency, were incubated in the radiolabelled putative neurotransmitter, L-glutamate. Quantitative electron microscope autoradiography revealed that the axoplasm of these recovering terminals had accumulated the3H L-glutamate.Acknowledgment. The authors wish to thank Dr N. M. Blackett for running the computer analyses of the autoradiographical results. R. P. Botham gratefully acknowledges the SRC for financial assistance. 相似文献
53.
The serum IgE levels measured by RIST correlated closely with those obtained by the single radioimmunodiffusion method. Values for husband and wife were closely related as were those between father and daughter but in contrast to previous observations no significant relationship existed between IgE levels for mother and son. 相似文献
54.
R. P. Botham D. J. Beadle R. J. Hart C. Potter R. G. Wilson 《Cellular and molecular life sciences : CMLS》1978,34(2):207-208
Summary Neural stimulation at high frequency induced gross changes in the ultrastructural properties and depleted the synaptic vesicles in fast axon terminals of locust extensor tibiae muscles. After a 1-h-rest the synaptic vesicle populations recovered and the ultrastructural properties of these recovering neuromuscular junctions closely resembled those of the controls.Acknowledgment. The authors wish to thank Mr M. J. Parker for invaluable help with the statistical analyses. R. P. Botham gratefully acknowledges the SRC for financial assistance. 相似文献
55.
Duplication and remoulding of tRNA genes during the evolutionary rearrangement of mitochondrial genomes 总被引:8,自引:0,他引:8
During the evolution of sea urchins, a transfer RNA gene lost its tRNA function and became part of a protein-coding gene. This functional loss of a tRNA with specificity for one group of leucine codons (CUN, where N is any base) was accompanied by the gain of a new tRNA with that specificity. The new tRNA gene for CUN codons appears to have evolved by duplication and divergence from a tRNA gene specific for another group of leucine codons (UUR, where R is a purine). These proposals account for (1) the strong sequence resemblance between the modern tRNA genes for CUN and UUR codons in Paracentrotus, (2) the altered location of the CUN gene in mitochondrial DNA of this urchin, and (3) the persistence of a 72-base pair sequence containing a trace of the old CUN gene at its original location. The old CUN gene now codes for an extra 24 amino acids at the amino end of subunit 5 in NADH dehydrogenase. Besides giving clues about the mechanisms by which tRNA genes move during mitochondrial DNA evolution, this finding leads us to propose a pathway relating the arrangements of other genes in mitochondrial DNAs from four animal phyla. 相似文献
56.
Control of malarial invasion by phosphorylation of the host cell membrane cytoskeleton 总被引:4,自引:0,他引:4
It has been shown that the entry of the malaria parasite into the red blood cell requires the presence of ATP in the host cell cytoplasm. In red blood cell ghosts that contain no ATP the receptor on the extracellular surface remains in place and parasites will bind to the membrane, but will not enter. ATP is thus necessary for one of the steps in the invasion sequence that follows recognition and attachment. The process of entry appears to involve the active participation of the host cell membrane cytoskeleton. We have suggested that the function of the intracellular ATP may be to regulate phosphorylation of the cytoskeleton. We now present evidence that the activity of the membrane-associated cyclic AMP-independent kinase of the red blood cell is inseparable from invasion; the active substrate may be spectrin. 相似文献
57.
J. F. Lynch J. M. Wilson H. Budzikiewicz C. Djerassi 《Cellular and molecular life sciences : CMLS》1963,19(4):211-213
Zusammenfassung Ein einfaches Glas-Einlass-System wird beschrieben, das die direkte Einführung von organischen Substanzen in die Ionisationskammer eines Massenspek trometers gestattet. Es ist somit möglich Massenspektren von Substanzen zu bestimmen die man bisher nicht aufnehmen konnte. Beispiele werden angeführt.
This paper represents part XXII in the seriesMass Spectrometry in Structural and Stereochemical Problems. For preceding article, seeE. Lund, H. Budzikiewicz, J. M. Wilson, andC. Djerassi, J. Amer. Chem. Soc., in press. 相似文献
This paper represents part XXII in the seriesMass Spectrometry in Structural and Stereochemical Problems. For preceding article, seeE. Lund, H. Budzikiewicz, J. M. Wilson, andC. Djerassi, J. Amer. Chem. Soc., in press. 相似文献
58.
59.
Metabolic availability of vitamin C in the guinea-pig 总被引:3,自引:0,他引:3
60.
随着21世纪的到来,博物馆管理员们也不得不面对很多新的问题,他们需要了解信息技术的发展,需要跟上时代的步伐。本书中收录的若干文章着重讨论了有关博物馆管理员今天所面临的问题。 相似文献