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81.
The herbicides amiprophosmethyl (APM) trifluralin, and oryzalin as well as the fungicides methylbenzimidazolyl carbamate (MBC), O-isopropyl N-phenyl carbamate (IPC), and chlorisopropyl N-phenyl carbamate (CIPC), which are known to cause the destruction of microtubules in vivo but do not interfere with tubulin polymerization in vitro, have been examined with respect to their ability to affect Ca2+ transport in isolated cell organelles. In contrast to colchicine which has no effect on Ca2+ transport in isolated mitochondrial and microsomal fractions, all of the substances investigated caused considerable reduction of ca2+ net uptake into mitochondrial but not into microsomal fractions. This reduction has been shown to be due to an increase in passive Ca2+ efflux. These results have been extrapolated to in vivo situations where they are postulated to act by raising cytoplasmic Ca2+ levels.Abbreviations APM
amiprophosmethyl
- CIPC
chlorisopropyl N-phenyl carbamate
- IPC
O-isopropyl N-phenyl carbamate
- MBC
methylbenzimidazolyl carbamate
- Mops
3-(N-Morpholino) propanesulfonic acid
- DMSO
dimethylsulfoxide 相似文献
82.
83.
Our purpose was to identify the effect of diminished plantar cutaneous sensation on time-to-boundary (TTB) measures of postural control during double and single limb quiet standing. Thirty-two healthy young adults underwent 10 min of ice immersion of the plantar aspect of the feet prior to balance testing. On a different day, the subjects did not receive this intervention prior to testing. A 2 × 2 vision (eyes open, eyes closed) by sensation (control, hypoesthesia) repeated measures design was used to analyze the TTB measures. In double limb stance, there were significant interactions between sensation and vision for the absolute TTB minimum and the mean of TTB minima in the anteroposterior (AP) direction. There was a significant increase in both measures after sensation was diminished with eyes closed compared to the control, but not with eyes open. In single limb stance, the TTB absolute minimum, the mean of TTB minima in the AP direction, and the standard deviation of TTB minima significantly increased with hypoesthesia regardless of vision. No significant differences were found in the medial–lateral (ML) direction for any of the TTB measures in double or single limb stance. Sensory information from the plantar cutaneous receptors appears to be most important in the maintenance of AP postural control. 相似文献
84.
Biodiversity effects on ecosystem functioning in forests have only recently attracted increasing attention. The vast majority
of studies in forests have focused on above-ground responses to differences in tree species diversity, while systematic analyses
of the effects of biodiversity on root systems are virtually non-existent. By investigating the fine root systems in 12 temperate
deciduous forest stands in Central Europe, we tested the hypotheses that (1) stand fine root biomass increases with tree diversity,
and (2) ‘below-ground overyielding’ of species-rich stands in terms of fine root biomass is the consequence of spatial niche
segregation of the roots of different species. The selected stands represent a gradient in tree species diversity on similar
bedrock from almost pure beech forests to medium-diverse forests built by beech, ash, and lime, and highly-diverse stands
dominated by beech, ash, lime, maple, and hornbeam. We investigated fine root biomass and necromass at 24 profiles per stand
and analyzed species differences in fine root morphology by microscopic analysis. Fine root biomass ranged from 440 to 480 g m−2 in the species-poor to species-rich stands, with 63–77% being concentrated in the upper 20 cm of the soil. In contradiction
to our two hypotheses, the differences in tree species diversity affected neither stand fine root biomass nor vertical root
distribution patterns. Fine root morphology showed marked distinctions between species, but these root morphological differences
did not lead to significant differences in fine root surface area or root tip number on a stand area basis. Moreover, differences
in species composition of the stands did not alter fine root morphology of the species. We conclude that ‘below-ground overyielding’
in terms of fine root biomass does not occur in the species-rich stands, which is most likely caused by the absence of significant
spatial segregation of the root systems of these late-successional species. 相似文献
85.
86.
From rats intravitally treated with dithizone (diphenyl-thiocarbazone) brains and spinal cords were removed and freeze-dried. The dithizonates present in the CNS tissue were extracted with carbon tetrachloride and subjected to a multielement analysis (proton activation, PIXE). It was found that the extract contained two metals. Most of the metal was zinc, but small traces of copper were also detected. Because prior treatment with the chelating agent, dithizone, can block both the Timm and the selenium metal staining methods, it is suggested that the three techniques label predominantly zinc in the neuropil (DTS-zinc). 相似文献
87.
R. Hertel 《Molecular & general genetics : MGG》1965,96(2):105-115
Summary Gene function of various T4-heterozygotes was tested. About half of the HETs containing wild type and anam-mutation disappeared under non-permissive conditions, if theam-defect concerned early functions. The same was found when phages, heterozygous forr
+ and anrII-point-mutation, were adsorbed to K12 (). A much more extensive loss of HETs in K could be observed if anrIIA- and anrIIB-point-mutation (block-mutations showed different results) occurred together in a non-recombinant heterozygote. The findings provide evidence that one class of T4-heterozygotes has a heteroduplex DNA-structure.With 3 Figures in the Text 相似文献
88.
R. Hertel 《Molecular & general genetics : MGG》1963,94(4):436-441
Summary The analysis of the progeny from three-allelic, triparental one-factor crosses in T4 showed a fraction of phages carrying allthree markers inone particle. Thesethree-allelic heterozygotes were observed in therII-region as well as in the host range gene. Their frequency (0.01–0.04% of total yield) was in the range expected from theory. This result is discussed with respect to the current picture of circular permutation in phage T4.With 1 Figure in the Text 相似文献
89.
90.
Carbon isotope ratios of herbarium material from members of the fresh-water families Podostemaceae and Hydrostachyaceae (Rosidae) were analyzed. The levels of 13C were highly variable (Podostemaceae −12.8‰ to −38.55‰; Hydrostachyaceae −10.78‰ to −30.42‰), across as well as within species and across a wide geographic range.
We suggest that the high variance observed is due neither to a constant attribute of the species like the photosynthetic CO2-carboxylase (in water plants with very high discrimination of the 13CO2 probably Rubisco) nor to the constant structural peculiarities of these species. Rather, it is likely due to the ‘diffusional resistance’ for the CO2-flux from the turbulent and/or fast flowing water, causing a very variable boundary layer on the plant surface. 相似文献