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21.
The activities of lysozyme, myeloperoxidase, and elastase were lower in PMNs and AMs from GF and AF Minnesota miniature piglets than in the leukocytes from their CONV counterparts. In the spleen and serum of gnotobiotic piglets only the levels of lysozyme were slightly reduced. Substantially depressed activities of these LEs were found also in PMNs from precolostral piglets in comparison with PMNs from their CONV mother. The bisassociation of GF piglets with Enterococcus liquefaciens and Escherichia coli caused an increase of LE activities in their AMs, spleens, and sera. Fewer LEs were released after phygocytic stimulation with zymosan from PMNs of GF, AF, and precolostral piglets than from PMNs of CONV animals of the same age. These data suggest that the antigenic-microbial stimulation is important for the development of normal lysosomal enzyme activities in PMNs and AMs from gnotobiotic animals. 相似文献
22.
The binding of isolated high mobility group proteins HMG (1+2) with nucleosomes was studied using gel electrophoresis. The interaction of HMG (1+2) with mononucleosomes could be detected as a new discrete electrophoretic band with a decreased mobility only after cross-linking of HMG (1+2)-nucleosome complex by formaldehyde. Approximately two molecules of the large HMG proteins were bound per nucleosomal particle of a DNA length of 185 base pairs, lacking histones H1 and H5. Using the same techniques, no binding was observed with core particles of a DNA length of 145 base pairs. 相似文献
23.
24.
We developed a mathematical model and an algorithm for numerical treatment of a model of honeycomb construction in a beehive. The model contains essential features of the bee-bee and bee-wax interactions, and in a qualitative way captures the dynamics of parallel comb construction. The construction is represented by a set of dynamical coupled partial differential equations for the density of bees situated on the hive ceiling, and the quantity of wax distributed by the bees. A spectral algorithm is invented for treatment of these equations, based on a modified thin-sheet gain scheme and a fast Fourier transform technique.Work at City College supported in part by the Army Research Office and the Department of Energy 相似文献
25.
UDPglucosyltransferase and its kinetic fluorimetric assay 总被引:1,自引:0,他引:1
A rapid, kinetic assay for UDPglucosyltransferase has been developed using 1-naphthol as substrate. It is based on the continuous fluorimetric monitoring of 1-naphthyl glucoside formation during the reaction at physiological pH. The conjugate is easily distinguished from aglycone, since their fluorimetric properties differ. Glucoside biosynthesis in vitro by microsomal preparations isolated from the gut and fat body of cockroaches Periplaneta americana and Leucophaea maderae, and from the green gland and hepatopancreas of the crayfish Astacus astacus, has been demonstrated. The effects of buffer, pH, MgCl2, UDP-glucuronic acid, UDP-N-acetylglucosamine, sodium cholate and sonication on the enzyme activity have been assessed. The kinetic parameters of 1-naphthol and UDP-glucose have also been determined. 相似文献
26.
Agrobacterium radiobacter, strain B6 (a strain isolated in this laboratory, which limited the occurrence of damping-off of sugar beet and influenced growth of plants in hot-house and field experiments) was found to produce an acidic exopolysaccharide in a mineral medium with various carbon sources. Hydrolyzates of the polysaccharide contained glucose, galactose, glycerol, succinic acid and pyruvic acid, whose quantitative content varied according to the carbon source used. The polysaccharide isolated from the medium containing glucose exhibited the highest physiological activity. Seeds germinated best and sugar beet roots were found to grow most rapidly in a medium containing 0.2 % (W/W) of the polysaccharide. The roots exposed for 3 d in this medium grew 2.7-fold as compared with non-treated plants. Higher sumbers of microorganisms were detected on the surface of roots treated with the polysaccharide. Growth of roots was also stimulated when immersing the seeds (30 min) in a 0.2 –0.4 % solution of this polysaccharide. After a two-fold treatment the roots were less damaged by the fungusPythium ultimum. Plants from seeds treated with the polysaccharide grew in the field soil more rapidly than the non-treated plants but worse than after bacterization of the seeds byA. radiobacter B6 and were only partially protected against the damping-off of sugar beet. 相似文献
27.
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
28.
Eva Klozová Jiřina Švachulová J. Smartt E. Hadač Věra Turková Véra Hadačová 《Biologia Plantarum》1983,25(4):266-273
The seed protein patterns of 12Arachis species were compared by polyacrylamide gel electrophoresis (PAGE), similarities between patterns were measured by the Jaccard
index. Results obtained confirm the close relationships established between members of the genus on morphological grounds
and support the more recent classification schemes.A. villosa andA. correntina could well be regarded as distinct species on grounds of protein differences whileA. macedoi andA. villosulicarpa (although members of the same section, Extranervosae) show considerable differentiation of their protein patterns. Surprisingly,
the formA. ×batizogaea showed less similarity in protein pattern to those of its parental species than might have been expected. The principle value
of seed protein pattern data appears to be in distinguishing species within sections. 相似文献
29.
The present report is focused on the study of participation of exogenous DNA in the process of postirradiation reparation of meristematic cells ofVicia faba primary roots. It is aimed at comparison of the positive reparative effect of isologous DNA with postirradiation action of heterologous DNA in its native, thermally denatured and DNAase-degraded forms, or DNA degraded by ultrasound, and with the effect of other biologically important macromolecules (RNA, histone, heparin, and dextran sulphate). For this purpose, the roots ofVicia faba irradiated by 150 r exposure were cultivated in solutions containing the above substances for an appropriate time interval. In squash slides both mitotic activity of the investigated cell population and frequency of postmetaphase chromosomal aberrations induced by radiation were evaluated. It was shown that a stimulation of cell division and reparation of chromosome damages were supported exclusively by isologous DNA. On the contrary, exogenously applied heterologous DNA increased postirradiation frequency of aberrations; maintenance of native structure of applied DNA was an essential condition for the above effect. Other macromolecules investigated on the course of postirradiation reparation ofVicia faba meristematic cells were without effect. 相似文献
30.
The localization ofl-asparaginase (l-asparagine amidohydrolase, EC 3.5.1.1) EC-2 isoenzyme was studied inEscherichia coli ATCC 9637 grown under conditions of moderate aeration. The enzyme was determined in cell fractions obtained by fraction centrifugation
of lysed spheroplasts. When the synthesis of the enzyme was induced byl-asparagine, its amount in the cytoplasmic fraction at the beginning of the induction exceeded as much as five times that
in uninduced cells, attaining up to 20% of the total activity. In the course of growth of the culture this activity decreased
gradually to zero. The membrane fraction of induced cells contained considerable amount of EC-2l-asparaginase which, at the beginning of the induction, reached up to 6% ot the total enzymic activity; in membrane fraction
of control cells the activity was close to zero. The results indicate a relationship of cell structures to thel-asparagine-induced synthesis of the enzyme. 相似文献