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941.
Ulf-Rüdiger Heinrich Raimund Kaufmann Herwig O. Gutzeit 《Differentiation; research in biological diversity》1984,25(1-3):10-15
Abstract. Cations were precipitated with potassium antimonate in ovarian follicles of Drosophila and the distribution of the formed precipitates was studied. The precipitates were analyzed with a laser microprobe mass analyzer (LAMMA) and found to contain a high concentration of calcium; potassium and sodium were also detected. On counting the antimon precipitates in stage 10B follicles with the electron microscope, few precipitates per unit area were found in anterior nurse cells, but more in posterior nurse cells; the highest precipitate density occurred consistently in the oocyte. When follicles of different stages were compared, the precipitate density was found to increase in the ooplasm and in the posterior nurse cells during vitellogenesis, whereas it remained nearly constant in the anterior nurse cells. Thus, the ratio of precipitates between the posterior and anterior end of the follicle increases during vitellogenesis. It begins to decrease at the time when the nurse cells collapse. These results suggest that the electrical polarity observed in polytrophic ovarioles may be based on differences in the cation distribution along the antero-posterior axis of the follicle. 相似文献
942.
The activity of superoxide dismutase (SOD) from bovine erythrocytes was measured by the inhibition of nitrotetrazolium blue reduction rate in superoxide anion radical generation systems--xanthine/xanthine oxidase of NADH/phenazine methasulfate. The enzyme activity increases in the presence of compounds acting as electron donors in radical-involving reactions and decreased in the presence of compounds possessing the properties of electron acceptors. Activation of SOD by electron donors and its inhibition by electron acceptors was dependent on the concentration of the above compounds. In the absence of SOD electron donors and acceptors did not change the rate of tetrazolium blue reduction by superoxide anion radicals. The role of the new type of SOD regulation for the enzyme functioning in the cell is discussed. 相似文献
943.
Iodine concentration by the fungus Penicillium chrysogenum inhabiting soils of the nonchernozem zone
S V Letunova S A Alekseeva E M Korobova 《Nauchnye doklady vysshe? shkoly. Biologicheskie nauki》1986,(10):94-98
The iodine accumulation by strains of microscopic fungi Penecillium chrysogenum isolated from soddy-middle podzolic soils of Kirov region has been studied. It has been shown that fungi are able to accumulate from 5,0 X 10(-5) to 10,2% of iodine depending upon the medium iodine content and the degree of the organisms' tolerance to its high concentrations. 相似文献
944.
T P Chernobel' T I Randmaa Z Ia Maksimova A A Shinkorenko V N Migunov 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1987,(11):88-90
A total of 218 batches of blood preparations produced from different raw materials have been studied by means of enzyme immunoassay kits (Abbott Laboratories, USA). The assays have revealed that the preparations under study are nonstandard with respect to the content and isolation rate of HBsAg, the marker of hepatitis B virus. These data necessitate search for the ways of improving the quality of blood preparations. 相似文献
945.
Identification of the functional site of erythrocyte protein 4.1 involved in spectrin-actin associations 总被引:23,自引:0,他引:23
I Correas T L Leto D W Speicher V T Marchesi 《The Journal of biological chemistry》1986,261(7):3310-3315
Peptides produced by mild chymotryptic digestion of human erythrocyte protein 4.1 mimic the ability of intact 4.1 to promote the binding of spectrin to F-actin. This complex-promoting activity was found to reside in an 8-kDa peptide which was fully functional when dissociated from other protein 4.1-derived peptides, indicating that noncovalent complexes of multiple peptides were not essential for activity. The 8-kDa peptide was incorporated into a ternary complex with spectrin and F-actin in approximately stoichiometric amounts. Amino acid composition and two-dimensional peptide mapping show that the 8-kDa active peptide is located within the 10-kDa region of protein 4.1 which contains a cAMP-dependent phosphorylated site. 相似文献
946.
947.
Peter V Scott 《BMJ (Clinical research ed.)》1982,285(6350):1277-1278
948.
E S Revazova Iu N Solov'ev T M Khizhniakova T V Iudicheva 《Biulleten' eksperimental'no? biologii i meditsiny》1985,99(4):469-471
The authors describe human cancer strains established from 6 cell lines transplanted to nude mice and rats: cancer of the liver, colon, lung, bladder and Burkitt's lymphoma. In spite of a long history (for several years) of cell line transfers in vitro, on transplantation of tumor cells, nude animals established tumors histologically identical to the primary cancer. 相似文献
949.
950.
K. V. Minin 《Paleontological Journal》2012,46(8):927-935
A study of the morphological variability of seven species of sea urchins of the genus Echinus from the Northeast Atlantic and Arctic with different depth preferences showed that in the group of species E. tenuispinus, E. esculentus, E. melo, E. acutus, E. elegans, E. affinis, and E. alexandri, arranged based on increasing depth of occurrence, the maximum test diameter decreases, the diameter of the apical system increases, the ratio of the number of interambulacral plates to the number of ambulacral plates increases, buccal and periproctal spines tend to disappear, and the number of ambulacral plates lacking a primary tubercle sharply decreases. At the same time, the test height decreases, while the number of secondary tubercles on coronal plates and number of lateral teeth on the valves of the globiferous pedicellariae increases. The change in the first six characters reflects the process of retention of juvenile features in deep-water Echinus. Similar trends in test height, apical system diameter and the ratio of the number of interambulacral plates to the number of ambulacral plates are recorded while comparing shallow-water and deep-sea populations of the eurybathic species E. acutus. This suggests that this species may currently be in the process of speciation. 相似文献