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21.
Exploratory data analysis based on multivariate statistical analysis techniques was introduced as a new approach to expressing
the toxicity of chemical substances at the simultaneous acceptance of various cell models. Using principal component analysis
and cluster analysis methods the toxicity of chlorinated phenol derivatives on employing some of the cell models (chlorococcal
algae, cyanobacteria, bacteria, micromycetes, plant and animal cells) was characterized. The previous empirical experience
that the toxicity of chlorinated phenol derivatives will increase with a growing degree of chlorination and that the presence
of the methoxy group will cause a lowering of the toxic effect was demonstrated. The relationship between groups of tests
used was presented. 相似文献
22.
Ninety-fourStaphylococcus aureus strains isolated from chronic and recurrent skin and respiratory tract infections were investigated for several virulence
factor expressions. Production of protein A was noticed in all of the tested strains in amounts from less than 0.1 to more
than 2.5 ng per 106 bacterial cells. The percentage of the extracellularly produced protein A was found to lie between 4.5 and 27.8%. Two strains
(both from the respiratory tract) produced more than 50 % of protein A in the extracellular form and one strain did not produce
any detectable amount of the extracellular protein A; 99 % of the tested strains produced the clumping factor, 96% staphylocoagulase,
79 % staphylokinase and 90 % gelatinolytic activity; 79 % produced α-toxin exclusively or in combination with δ- or β-toxin;
8 % of strains produced β-toxin. There were differences in β-toxin production between strains from the respiratory tract (5
%) and skin infections (25 %). δ-Toxin was produced by 53 % of the strains. In each of the tested strains a complex of virulence
factors was detected. The importance of inactivated extracellular products (especially α- and δ-toxin and in the case of skin
infections also β-toxin) as components of staphylococcal whole-cell vaccine was suggested.
Dedicated to Professor C. John on the occasion of his 75th birthday 相似文献
23.
A G Zhu?kov 《Radiobiologiia》1984,24(3):380-383
As shown on the in vitro irradiated Ehrlich ascites tumor cells the increase in the intensity of ultraviolet fluorescence (UVF) of the exposed cells occurs only in such incubation conditions when an increase in the tryptophan content of irradiated cells becomes possible. The increase in the UVF intensity and in the tryptophan content are quantitatively identical. It is concluded that the increase in the content of the fluorescing substance, tryptophan, in the irradiated cells is the cause of the increase in the UVF intensity. 相似文献
24.
25.
Complications due to antibiotic therapy in rheumatic patients subjected to season bicillin prophylaxis in Minsk within 1965--1975 and in patients with extensive collagenoses were studied. Allergic complications mainly ih the form of allergic reactions in the patients treated with bicillin-3 or picillin-5 were observed in 7.8--16.8 per cent of the patients. Within 10 years 52 cases of anaphylactic shock due to the bicillin use were recorded. Side reactions to antibiotics were observed in 16 (17.3 per cent) out of 92 patients with extensive collagenoses. For prophylaxis of the above complications it is recommended to use rational antibiotic therapy in rheumatic patients, strict registration of allergological states in the anamnesis, testing of microbial sensitivity to the antibiotics. 相似文献
26.
Conformational analysis of immunoglobulin G3 (IgG3) hinge region repeating part was performed. In approximation of backbone regular conformations for the case of C2 symmetry (the symmetry axis is perpendicular to S-S bridges and passes through their midpoint) on the basis of total analysis of ring geometry possibilities and estimation of steric conditions, the existence of two conformations with n = 3 (3(10) helix type and polyproline II type) was inferred. A possible role of these conformations in the immunoglobulin functioning was discussed. 相似文献
27.
Use of whey for production of exocellular polysaccharide by a mutant strain ofXanthomonas campestris
Growth and kinetics of the production of exocellular polysaccharide was studied in a mutant strain ofXanthomonas campestris lac
+ during cultivation in a submerged culture in a medium containing whey. The maximum production of the polymer was observed
at the initial stage of the stationary growth phase of the culture. The mean production yield was about 1.4%. The results
were comparable with those obtained during cultivation on a lactose medium.
Translated by Č. Novotny 相似文献
28.
I. Studničková 《Folia microbiologica》1979,24(6):478-482
The relationship between the logarithm of nitrification intensity and moisture (expressed as pF) did not have an ideal linear course in structural soils in which pores of a certain size predominated. When increasing the incubation moisture it could be observed that the intensity of nitrification decreases at pF 3.5-4.4 and increases again on further increasing the incubation moisture. The detected anomaly was observed when applying moistures corresponding to peaks of derivation pF-curves. It can be assumed that the relationship between the intensity of nitrification and moisture is modified by soil microstructure; therefore, this relationship was studied in more detail in the present communication. 相似文献
29.
Jlřina DvOřáková-Hladká 《Biologia Plantarum》1976,18(3):214-220
The paper deals with the problem of the significance of Ca2+ for the growth of algae, its participation in the process of nitrate and ammonium nitrogen utilization, and with the possibility of substituting Sr2+ for it. It was revealed that calcium represents a microbiogenous element for the algae tested, which takes part in the utilization of nitrate nitrogen. It cannot be replaced by strontium especially at a high growth rate of mixotrophically cultivated algae (ina glucose medium). 相似文献
30.
Summary Mineralized plaques, which develop at the site of repeated subcutaneous injections of 100 g KMnO4/0.2 H2O in rats, were investigated by electron microscopy. The newly formed, delineated, white plaque tissue at the injection site consisted of numerous, mostly unaltered fibroblasts and collagen fibers, without participation of inflammatory cells. Some signs of cell injury were found in the center of the lesions. Numerous, irregularly distributed, small, mineralized foci were seen near the fibroblasts. These were formed by aggregation of small needle-like units (50 Å in diameter and 0.05–2.0 m long). These needle-shaped units were found either in vesicular, cell derived structures, considered to be shed cell processes or cell fragments, or on collagen fibers. Intramitochondrial deposits of such needle-like units were seen frequently. Fusion of smaller mineralized foci to larger plaques occured and then needle-shaped units were seen at the periphery of the electron-dense lesions. Hypotheses concerning the mechanism of experimental cutaneous calcinosis (soft tissue mineralization) are discussed and related to the findings of this study. Probable intracellular crystal deposition and mineralization in cell-derived structures were shown for the first time in topical cutaneous calcinosis. 相似文献