共查询到20条相似文献,搜索用时 15 毫秒
1.
Olabanji SO Olubunmi P Ceccato D Buoso MC De Poli M Moschini G 《Biological trace element research》2005,107(2):181-197
There is need to evaluate the locally available animal feeds in Nigeria so as to be able to combine them in acceptable proportions
to the animals to achieve the desired growth rate. The technique of particle-induced X-ray emission (PIXE) was employed for
the evaluation of these locally available animal feeds, which include Panicum maximum (Guinea grass), Cynodon plectostachyum (grass), Leucaena leucephala (legume), Calopogonium mucunoides (legume), Gliricidia sepium (legume), Euphorbia polychrome (legume), Pueraria phaseloides (legume), and Centrosema pubescens (legume). The proton beam delivered by the 2.5-MV AN 2000 Van de Graaff accelerator at the International Centre for Theoretical
Physics Laboratori Nazionali di Legnaro (LNL), Padova, Italy was used for the PIXE measurements. Twenty-one different elements
were detected at various concentrations and their nutritional effects on different animals are discussed. 相似文献
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Evan T. Williams 《Biological trace element research》1987,12(1):19-31
The analytical technique of particle-induced X-ray emission (PIXE) is described, and recent applications to problems in biomedical
research are surveyed. 相似文献
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Szökefalvi-Nagy Zoltán Bagyinka Csaba Demeter István Kovács Kornél L. Le Quynh Huen 《Biological trace element research》1990,(1):93-101
A method is presented to identify and determine the relative amounts of protein-bound metal ionsin situ. Proteins or their subunits are directly scanned by a collimated proton beam of 3 MeV energy, and the characteristic X-rays
produced are detected. The determination of Fe content of an iron-sulfur protein (HiPiP), as well as the Fe and Ni analysis
of the hydrogenese fromThiocapsa roseopersina, have shown the feasibility of this technique. 相似文献
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Asano K Suzuki K Chiba M Sera K Asano R Sakai T 《Biological trace element research》2005,107(2):135-140
The concentrations of 28 elements (Al, Br, Ca, Cl, Co, Cu, Cr, Fe, Ga, Hg, K, Mg, Mn, Mo, Na, Nb, Ni, P, Pb, Rb, S, Se, Si,
Sr, Ti, V, Y, and Zn) were measured in mane hair by the particle-induced X-ray emission method. Except for Br, Cl, K, S, and
P, the trace element concentrations in mane hair of horses are similar to literature values for human hair. The values obtained
are not dependent on the horse's age, breed, and sex and could be used as reference values in the assessment of diseases and
nutritional status in equines. 相似文献
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The elements present in the fungal structures produced by Piedraia hortae in vivo and in vitro have been investigated using electron microscopy X-ray microanalysis. Phosphorus, sulphur and calcium were detected in the nodules which developed on hair and on colonies on culture. These elements belong to the extracellular material that compacts the pseudoparenchymatous organization of the fungus. They may be present due to the capacity of melanin-like pigments to sequester ions and/or they may form part of the sulphates and phosphates of the polyanionic mucopolysaccharides that constitute the extracellular material. Environmental contaminants such as aluminium, silicon and iron were detected exclusively on the surface of the nodule. They were deposited or linked to the residual molecules produced during the breakdown of the cuticular keratin. The advantages of these techniques for elucidating the chemical nature of fungal structures are discussed. 相似文献
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A microwave acid digestion method for the preparation of biological samples for PIXE analysis is presented. The precision and accuracy of the entire PIXE analytical procedure, including the micro-wave digestion step, were evaluated by analyzing eight certified reference materials. For elements heavier than K, and for concentration levels from 2 μg/g upward, the total random error of a single analysis is in the range of 2–5%. The accuracy is better than 5%. The detection limits are down to 0.3 μg/g.
相似文献10.
The verification of cytochemical tests for ATP-ase activity in plant cells using X-ray microanalysis
Summary Electron microprobe analysis (EMMA 4) was carried out on two types of electron opaque deposit found in thin sections of barley root tips as a result of cytochemical tests for ATP-ase activity.The granular type of deposit, which mainly occurs in radial and tangential cell walls of epidermal and sub-epidermal cells, was shown to contain lead, whereas lead was absent from the opaque globular deposits, which are much more generally distributed and always associated with membrane structures. Thus the latter deposits, which contain osmium and have often been interpreted as ATP-ase reaction products, should be regarded as artifacts of the fixation and rinsing procedures. It is suggested that calcium may play a role in the formation of the osmiophilic deposits. 相似文献
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Kari Hovind-Hougen Marina Cinco Godfried M. Roomans Aksel Birch-Andersen 《Archives of microbiology》1981,130(5):339-343
The morphology of cells of strain Muggia, a slightly halophilic leptospire, was examined by the negative staining technique.The ultrastructure of the cells was rather similar to that of cells of Leptonema illini, i. e. the cells possessed cytoplasmic tubules. The basal complex of their flagella, however, was similar to the corresponding part of flagella on Gramnegative bacteria. The interior of the cells was densely packed with inclusions, except for the two outermost wavelengths at each end where these inclusions were absent.X-ray microanalysis showed that the inclusions contained sodium and chlorine as their main constituents. The inclusions disappeared upon storage of the cultures at room temperature. 相似文献
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Calcium distribution was studied in oat caryopses. Using the chlorotetracycline method it was found that membrane-associated Ca2+ was present in the aleurone layer. X-ray microanalysis confirmed the presence of calcium in aleurone cells; it also demonstrated the presence of considerable amounts of calcium in the cell wall surrounding these cells.Abbreviation CTC
chlorotetracycline 相似文献
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Radiobiological effects of a low-energy ion beam on wheat 总被引:14,自引:0,他引:14
The radiobiological effects of a low-energy nitrogen ion (N+) beam on wheat were studied, particularly with regard to the induction of chromosome aberrations. The results demonstrated
that the three test varieties showed different sensitivities to ion implantation, and a higher dose of ion implantation had
a marked effect on the germination and survival rate of the seeds exposed. The germination rate and survival rate curve basically
followed a similar trend in the same variety. Cytological analysis indicated that ion beams were effective in producing chromosome
aberrations. The frequencies of mitotic or meiotic cells with chromosome aberrations increased linearly with increasing doses.
The aberration types included, for example, acentric fragments, chromosome deletions, lagging chromosomes, chromosome bridges
and micronuclei. In the root tip cells, aberrations chiefly consisted of acentric fragments and deletions. Chromosome bridges
and lagging chromosomes were the main aberration phenomena observed in the pollen mother cells. The highest frequencies of
root tip cells and pollen mother cells with chromosome aberrations were 15.2% and 39.8%, respectively. Changes in morphology
and mutant were also observed in the plants derived from exposed seeds.
Received: 10 April 2000 / Accepted: 10 October 2000 相似文献
15.
《Micron (1969)》1979,10(2):141-143
A method is described for the preparation of specimen supports for X-ray microanalysis. Spectroscopically pure graphite rods or other high purity carbon can be shaped and drilled mechanically or cut with the aid of a laser beam to make suitable supports which do not produce extraneous background counts. 相似文献
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Chromium pollution of freshwater is hazardous for humans and other organisms, and places a limitation on the use of polluted
water sources. Phytoremediation, the use of plants to remove pollutants from the environment, is a cost-effective, environmentally
friendly approach for water decontamination. To improve the efficiency of the process, it is essential to increase the current
knowledge about Cr accumulation in macrophytes. Plants of Iris pseudacorus L. were treated with Cr(III) at 0.75 mM for 5 weeks to investigate Cr localization by means of transmission electron microscopy
and energy dispersive X-ray analysis. Chromium induced severe ultrastructural alterations in the rhizodermis (cell wall disorganisation,
thickening, plasmolysis, and electron-dense inclusions) and rhizome parenchyma (reduced cell size, cell wall detachment, vacuolation,
and opaque granules). The highest Cr contents were found in the cell walls of the cortex in the roots and in the cytoplasm
and intercellular spaces of the rhizome. The Cr concentration in root tissues was in the order cortex >rhizodermis >stele,
whereas in the rhizome, Cr was evenly distributed. It is proposed that root and rhizome have distinct functions in the response
of I. pseudacorus to Cr. The rhizodermis limits Cr uptake by means of Si deposition and cell wall thickening. The rhizome cortex generates
vacuoles and granules where Cr co-occurs with S, indicating Cr sequestration by metal-binding proteins. 相似文献