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31.
32.
Effect of the arbuscular mycorrhizal symbiosis upon uptake of cesium and other cations by plants 总被引:1,自引:0,他引:1
Pot experiments were set up to determine the species-specific uptake of cesium (Cs) by mycorrhizal (AM) and non-mycorrhizal
(non-AM) plants. Using stable Cs and K application, side-effects of mineral fertilization (K) on AM development and uptake
of Cs and the other cations Na, Ca and Mg were investigated. AM colonization by the fungus Glomus mosseae led to a significant decrease in shoot Cs content of Agrostis tenuis from the first (4 weeks) to the third harvest (8 weeks). With regard to the root system, statistically significant differences
were observed from the first (4 weeks) to the second harvest (6 weeks). Supply of additional K produced a significant decrease
in Cs uptake by both AM and non-AM plants over a 10-week period. In the case of AM plant shoots, K fertilization did not very
effectively reduce Cs uptake by A. tenuis. Cs contents of fertilized AM roots were similar to non-AM controls. Potassium application resulted in an increase in K content
and a slight reduction in Na and Mg contents of shoots and roots. Without K fertilization, the Na content of non-AM controls
was significantly enhanced over AM shoots. Shoot and root Ca contents were generally higher without than with K addition.
Negative side-effects of K fertilization as a countermeasure to Cs uptake were not observed in relation to AM development.
The intensity of colonization by G. mosseae was not significantly depressed by K treatment. AM development in plants appeared to decrease Cs uptake, at least at moderate
nutrient levels. It is possible that Cs is sequestered by AM extraradical fungal hyphae and consequently not transferred to
the plant to the extent found in non-AM roots.
Accepted: 6 November 2000 相似文献
33.
Bandgap‐Tunable Cesium Lead Halide Perovskites with High Thermal Stability for Efficient Solar Cells 下载免费PDF全文
34.
35.
Maria Teresa Santini Silvia Paradisi Elisabetta Straface Walter Malorni 《Cell biology and toxicology》1993,9(3):295-306
The exposure of the epidermoid cell line A431 to different concentrations of CsCl was assessed using different methodological approaches. Two different effects were detected depending upon the concentration of the agent: at low concentrations, cell modification was represented mainly by a very pronounced cell flattening and an alteration of the cell-to-cell contacts, interpreted as an increase in cell adhesion. At higher concentrations, a clear pathogenic effect was observed that allowed the formulation of the hypothesis that specific mechanisms of toxicity at the subcellular level involving mitochondrial and cytoskeletal function can exist. In addition, membrane order parameters, as detected by electron paramagnetic resonance (EPR) spectroscopy, displayed a dose-dependent increase in membrane rigidity. Results reported here seem to suggest that cesium ions can enter the cell, modify plasma membrane integrity and alter some specific cytoplasmic components, e.g. the cytoskeleton. Considering that environmental contamination by cesium as a result of radioactive fallout is of major importance and that few data are available thus far on this matter, this study provides evidence for the possible mechanisms of action of the non-radioactive form of this ion in cells.Abbreviations 相似文献
36.
H.David Husic Clarence H. Suelter 《Biochemical and biophysical research communications》1980,95(1):228-235
The levels of creatine kinase and pyruvate kinase are increased 22 and 9.3 fold respectively in the blood plasma of dystrophic chickens as compared to normal controls. AMP aminohydrolase levels are not increased despite their abundance in muscle tissue. When AMP aminohydrolase was injected into a blood vessel, its rate of disappearance from the plasma was rapid with 97% of the enzyme disappearing with a half-life of 3.3 minutes. In contrast, the rate of disappearance of pyruvate kinase from the blood plasma is relatively slow, following a biphasic exponential decay with half-lives of 113 min and 710 min. These data suggest that the rates of disappearance of enzymes from the blood plasma is an important factor in determining whether increased plasma levels of these enzymes are observed in muscular dystrophy. 相似文献
37.
Cesium chloride treatment of illuminated barley leaves leads to accumulation of uroporphyrinogen which is subsequently either
oxidised to uroporphyrin in continuous light or converted to protochlorophyllide in darkness [Shalygo et al. (1998) J Photochem
Photobiol 42: 151–158]. We were interested to elucidate the differences in the phototoxicity of uroporphyrin and protochlorophyllide
in the CsCI-treated leaves. Photosensitization and the induction of oxidative stress responses in the barley leaves occurred
much faster upon protochlorophyllide than upon uroporphyrin accumulation. We compared the time resolved changes in the pool
sizes of low molecular weight antioxidants, such as ascorbate, glutathione and tocopherol, as well as of the enzymatic activities
of catalase, ascorbate peroxidase, glutathione reductase and superoxide dismutase in illuminated barley leaves which accumulated
uroporphyrin or protochlorophyllide. A rapid loss of the antioxidant levels correlated with the accumulation of reactive oxygen
species. The contents of low molecular weight antioxidants and the activities of most of the antioxidative enzymes declined
more rapidly in the presence of protochlorophyllide than of uroporphyrin. Due to its high lipophilicity, free protochlorophyllide
is associated with biomembranes. Therefore, it is assumed that it exerts its phototoxic effects to membranes more rapidly
than uroporphyrin.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
38.
The effects of K+ growth conditions on the accumulation of cesium by the bacterium Thermus sp. TibetanG6 总被引:1,自引:0,他引:1
A number of nuclear tests carried out during the 1950s, as well as nuclear accidents like Chernobyl, revealed large numbers of radionuclides such as ura-nium and cesium in the environment. The develop-ment of a nuclear industry also contributed to the pol… 相似文献
39.
HeLa cell polysomes were oxidized with sodium periodate and reduced with sodium borohydride to induce covalent crosslinks between ribosomal RNA and nearby proteins. We proved that RNA was tryly crosslinked to protein in oxidized, and not in control, samples using denaturing cesium trichloroacetate density gradients and phenol extraction. By both one- and two-dimensional gel analysis, we found that protein S3a can be crosslinked to 18S RNA, protein L3 to 28S RNA, and proteins L7′ and L23′ to 5.8S RNA. Because of the specificity of the periodate reaction, and since we were able to crosslink protein S1 to 16S RNA in , 30S ribosomal subunits, it is likely that we have crosslinked proteins to the 3′OH ends of HeLa polysomal RNAs. 相似文献
40.
Cesium Doped NiOx as an Efficient Hole Extraction Layer for Inverted Planar Perovskite Solar Cells 下载免费PDF全文
Wei Chen Fang‐Zhou Liu Xi‐Yuan Feng Aleksandra B. Djurišić Wai Kin Chan Zhu‐Bing He 《Liver Transplantation》2017,7(19)
Organic–inorganic hybrid perovskite solar cells have resulted in tremendous interest in developing next generation photovoltaics due to high record efficiency exceeding 22%. For inverted structure perovskite solar cells, the hole extraction layers play a significant role in achieving efficient and stable perovskite solar cell by modifying charge extraction, interfacial recombination losses, and band alignment. Here, cesium doped NiOx is selected as a hole extraction layer to study the impact of Cs dopant on the optoelectronic properties of NiOx and the photovoltaic performance. Cs doped NiOx films are prepared by a simple solution‐based method. Both doped and undoped NiOx films are smooth and highly transparent, while the Cs doped NiOx exhibits better electron conductivity and higher work function. Therefore, Cs doping results in a significant improvement in the performance of NiOx‐based inverted planar perovskite solar cells. The best efficiency of Cs doped NiOx devices is 19.35%, and those devices show high stability as well. The improved efficiency in devices with Cs:NiOx is attributed to a significant improvement in the hole extraction and better band alignment compared to undoped NiOx. This work reveals that Cs doped NiOx is very promising hole extraction material for high and stable inverted perovskite solar cells. 相似文献