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Cytogenetic analysis of peripheral blood lymphocytes in glass workers occupationally exposed to mineral oils 总被引:3,自引:0,他引:3
Chromosome aberration tests were carried out in a group of 31 pressed glass makers operating an automatic line of press-and-blow machines known to release mineral oil mists containing relatively high concentrations of the mutagenic chemicals belonging to a class of polycyclic aromatic hydrocarbons (PAH). The workers were exposed to the mineral oil aerosol levels that did not exceed the Czechoslovak maximum allowable concentration limit of 5 mg . m-1 of air. The tests revealed that the frequency of aberrant cells (% AB.C.) and the value of breaks per cell (B/C) ratio found in mineral oil-exposed workers were increased significantly, accounting for 4.65 +/- 0.29% AB.C. (0.0532 B/C) vs. 1.13 +/- 0.19% AB.C. (0.0113 B/C) seen in matching controls. Also, a higher rate of dicentrics, reciprocal translocations and cells with pulverization was observed in this group of glass workers. These finding are considered as evidence suggesting that these workers might experience an increased risk of genetic injury due to exposure to mineral oil mists. 相似文献
34.
Changes in carbohydrate composition in wheat and pea seedlings induced by calcium deficiency
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Wheat (Triticum aestivum L. cv Jubilar) seedlings were grown for 10 days in hydroponics with or without calcium. In the leaves, Ca deficiency caused the level of ethanol soluble carbohydrate to increase between 2-and 10-fold, enhanced dark respiration and decreased CO2 fixation capacity. Sucrose was the major carbohydrate to accumulate in wheat roots. 相似文献
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Zdeněk Hostounský 《Journal of invertebrate pathology》1984,44(2):166-171
The microsporida Nosema gastroideae and N. equestris, which are highly pathogenic for Leptinotarsa, have been successfully produced in some other chrysomelid species, Gastrophysa polygoni and G. viridula. As the principal target host, Leptinotarsa is very susceptible to these pathogens, and death occurs before massive sporulation by the microsporidia. By contrast, the infected larvae of G. polygoni or G. viridula are able to develop until the adult stage when most of the tissues become filled with spores. In addition, the larvae and adults of these species can be reared in the laboratory on Polygonum aviculare and Rumex obtusifolius. These plants have longer vegetative periods and are better sources of food than potato leaves. In both species of Gastrophysa the yields of spores related to unit weight were about five times higher than in Leptinotarsa. In the adults of G. viridula there was up to 4.8 × 106 spores mg?1 body weight of N. gastroideae, or 9.1 × 106 spores mg?1 of N. equestris. The higher content of microsporidian spores facilitates their purification and isolation. 相似文献
37.
Respiration and microflora of the rhizosphere soil of wheat influenced by foliar application of urea
J. Vraný 《Folia microbiologica》1983,28(2):118-123
The numbers of micromycetes and bacteria were investigated with respect to oxygen consumption in the rhizosphere soil of wheat
and in non-rhizosphere soil. Plants after foliar application of urea (2 % solution) and non-treated plants were cultivated
in degraded chernozem and garden soil in a green-house. Changes in oxygen consumption by the suspensions of rhizosphere and
non-rhizosphere soils corresponded to changes in the number of bacteria designated as the rhizosphere effect (R/S). Values
of R/S depended on the presence of organic substrates. Changes in oxygen consumption by the soil suspension from the rhizosphere
of wheat occurring due to foliar application of urea corresponded to changes in the amount of microflora. The results obtained
are discussed with respect to a possible utilization of the data to follow metabolic activity of soils in a natural environment
(in situ) determined according to oxygen consumption by a soil suspension, and to assess changes in the microflora of rhizosphere
and non-rhizosphere soil. 相似文献
38.
Foreign proteins penetrate across the wall of rabbit jejunum takes place within the first eight hours after birth. Sensitization by foreign protein (cow's milk protein) during early postnatal ontogeny is the cause of death of artificially fed germfree rabbits at the age of 21-23 d. 相似文献
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Solid-phase synthesis was used for the preparation of pyroglutamyl-histidyl-p-nitrophenylalanyl-phenylalanyl-alanyl-leucine amide (I) and glycyl-glycyl-histidyl-p-nitrophenylalanyl-phenylalanyl-alanyl-leucine amide (II), two water-soluble and sensitive chromophoric substrates of chicken pepsin, hog pepsin A, and bovine spleen cathepsin D. The kinetic constants of hydrolysis of the p-nitrophenylalanyl-phenylalanyl bond of the substrates were measured by difference spectrophotometry at 308 nm (Δ? = 860 m?1 cm?1) and by ninhydrin colorimetry (substrate I, ?570 = 2.31 × 104m?1 cm?1). The pH optimum of cleavage is 5 for the pepsins and 3.7 for cathepsin D. Since all three proteinases still have a significant activity at pH 5.5–6 a new, simple assay was designed for submicrogram quantities of pepsins in the presence of pepsinogens without interference of the latter. The method is particularly suitable for the analyses of the zymogen activation mixtures. 相似文献