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31.
High level of GUS gene expression driven by pollen-specific promoters in electroporated lily pollen protoplasts 总被引:8,自引:0,他引:8
Gene constructs that contained the -glucuronidase (GUS) gene under the control of a pollen-specific Zm13 promoter from maize and a LAT52 promoter from tomato were introduced by electroporation into pollen protoplasts isolated from bicellular pollen grains of Lilium longiflorum. After 20 h in culture, the pollen protoplasts exhibited the apparent expression of GUS in a fluorometric assay. The GUS activity induced under the control of the Zm13 promoter was over 10 000 times higher than activity in the control (with no DNA or without electroporation). By contrast, the GUS gene was nearly silent in the lily microspore protoplasts and generative cell protoplasts. The GUS activity driven by the Zm13 and LAT52 promoters was also detected by a cytochemical assay. The frequency of blue-staining pollen protoplasts was about 70% in the case of the Zm13 promoter. The efficiency of gene transfer by electroporation was much higher than by particle bombardment. This protoplast-specific electroporation system is suitable for rapid and reliable examination of pollen-specific promoters, being as good as the particle bombardment system. 相似文献
32.
Summary In an attempt to identify pancreatic islet cells emitting formaldehyde-induced fluorescence (FIF), the pancreatic islets of the domestic fowl were studied by combined fluorescence, ultrastructural, silver-impregnation and immunohistochemical methods in the same section or in consecutive semi-thin and ultra-thin sections. The results indicate that islet cells emitting intense FIF exhibit a strongly argyrophil reaction with the Grimelius' silver method and also immunohistochemical reaction with anti-glucagon serum, but not with anti-5-HT serum. Therefore, the fowl islet A cell, a peptide hormone-producing cell, stores simultaneously catecholamine as biogenic amine. The islet B and D cells did not display any FIF, any argyrophil reaction with the Grimelius' silver method, or any immunoreactivity with anti-glucagon or anti-5-HT sera. The fluorescent but non-argyrophil cells dispersed in the exocrine acinus may well be PP cells. 相似文献
33.
A new technique was devised for the dynamic detection of the axoplasmic transport of β-radioactively labeled materials in which a semiconductor radiation detector was used as the β-ray counter. The detector element is a silicon p-n junction diode and has a diameter of 2.0 mm. With this detector, the β-radioactive distribution of axoplasmic transport could be measured in an axon maintained physiologically without cutting nerves. This method makes possible determination of the transport rate using one bundle of peripheral nerves. The rate in the bullfrog was 6.4 mm per hour at 24.0 °C. Temperature effects on the bullfrog axoplasmic transport were also observed at different temperatures, ranging from 5.0 to 24.0 °C. At these temperatures the rate increased as an exponential function of temperature from 1.1 to 6.4 mm per hour. Within this temperature range, the Q10 is 2.5 and an Arrhenius plot of the natural logarithm of velocity versus the reciprocal of absolute temperature yielded an apparent activation energy of 14.8 Kcal. This technique offers great advantages in permitting direct study of the axoplasmic flow of the axon in a physiological condition. 相似文献
34.
When methylmercury was incubated in the presence of selenite and reduced glutathione (GSH), the mercury which was extracted into benzene under acidic condition decreased gradually with the elapse of time. This decrease was due to the cleavage of mercury-carbon bond of methylmercury. The reaction did not proceed when selenite or GSH was singly added to the reaction mixture. L-Cysteine, 2-mercaptoethanol and sodium sulfide in place of GSH also were effective for decomposition of methylmercury in combination with selenite, but oxidized glutathione (GSSG) and L-cystine were not. This suggests that reduction of selenite is needed for the degradation of methylmercury. Thus, the effect of reduced metabolites of selenite produced by GSH was investigated. Glutathione selenotrisulfide (GSSeSG) requierd GSH for the degradation of methylmercury, whereas H2Se possessed a strong activity even in the absence of GSH. This may indicate that H2Se is involved directly in the conversion of methylmercury to inorganic mercury. This phenomenon found in experiments is discussed in relation to the biotransformation of methylmercury. 相似文献
35.
The relationships among X591, Cyt-b559 and C-550 in the primaryphotoact of PS-II were analysed by examining the effects ofvarious inhibitory substances and treatments on the light-inducedabsorbance changes of these components. The results were fully explainable by the scheme previouslypresented by Huzisige, in which two photoreactions are involvedin PS-II. Our conclusion is that X591 acts as the electron acceptorfor one of the photoreactions in PS-II. (Received October 23, 1978; ) 相似文献
36.
Tohru Nakashizuka 《植被学杂志》1991,2(3):413-418
The growth and survival of coniferous and broad-leaved trees were followed over a 5-yr period in a temperate old-growth mixed forest in Japan, and dynamic features of the forest were studied in relation to the life history of the dominants, the coniferous Abies homolepis and the broad-leaved Fagus crenata. During this period, the gap formation rate was 31m2 ha?1yr?1, the mortality of trees > 2m high was 1.7%/yr, and the rate of loss in basal area 1.4%/yr. These values were much higher than the recruitment, 0.3%/yr, and the total growth of surviving and new trees, 0.6%/yr, owing to the inhibition of regeneration by understorey dwarf bamboo (Sasa borealis). A transition matrix model based on DBH size classes predicts that the basal area of the forest will decrease by 14% in 50 yr, but that the DBH distribution of trees > 10 cm diameter will change little. Equilibrium DBH distributions assuming recruitment being equal to mortality, were quite different between broad-leaved and coniferous trees, reflecting different survivorship curves of the two dominants. The composition and structure of the forest may change depending on the pattern and frequency of disturbances, or episodic events, notably the synchronous death of Sasa borealis. 相似文献
37.
Toshiaki Nagafuji Tohru Koide Tatsuo Miyauchi Michiaki Takato 《Journal of neurochemistry》1992,58(1):362-368
In search of factors mitigating the final outcome of ischemic and epileptic brain damage, we tested a novel dibenzoxazepine derivative (BY-1949), as the compound has been shown to be effective under these two conditions. First, using rat brain, we assessed whether or not BY-1949 affects the Na+,K(+)-ATPase activity. Although in vitro applications of either BY-1949 or its three major metabolites did not cause any apparent effects, both acute and chronic oral administrations of the compound (10 mg/kg) invariably increased the Na+,K(+)-ATPase activity in the synaptosomal plasma membranes by increasing Vmax values. Second, it was shown by this study that the drug treatment caused marked increases in the uptake of both glutamic acid and gamma-aminobutyric acid into the synaptosomes. These results suggest that the activity against ischemic/epileptic brain damage by BY-1949 is explicable, at least partly, in terms of improvement of ionic derangements across the neural membranes via Na+,K(+)-ATPase activation. 相似文献
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Corelike structures, which were interpreted as straight, large cylinders containing ribosome-like particles surrounded by
an amorphous substance of low electron density, were found in a stable L-form ofStreptococcus pyogenes grown in the absence of antibiotics. 相似文献