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31.
Details are reported for the synthesis of Se-carboxymethylselenohomocysteamine from selenohomocysteamine and monochloroacetic acid. Data on its behaviour on paper and ion-exchange chromatography are also reported, which allow its identification. 相似文献
32.
Silvana Faccio Dolfini 《Chromosoma》1978,69(3):339-347
The frequency of sister chromatid exchanges (SCEs) in two cell lines of Drosophila melanogaster with different karyotypes (XX and XY) was determined, considering (1) the distribution of SCEs within each chromosome, with reference to eu- and heterochromatin and (2) the distribution of SCEs in different chromosomes. A comparison was made between chromosome pairs within each karyotype and between the two different karyotypes. The following results were obtained. The SCEs are not randomly distributed along chromosomes, since exchanges were never observed in heterochromatin. SCEs are more frequent in XY than in XX cells; moreover, in both cell types there exists a significantly higher frequency of SCEs in the X chromosome than in the autosomes. These findings are discussed in relation to chromosome aberrations and mitotic recombination. 相似文献
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Summary Contraction and relaxation in glycerinated amoeba models are controlled by the same factors which are known to control streaming in demembranated, living cytoplasm of amoeba. Threshold calcium concentration for the transition from relaxed to contracted state of glycerinated model was found to be about 10–6 M. 相似文献
34.
C. de Marco A. Rinaldi M. R. Dessi' S. Dernini 《Molecular and cellular biochemistry》1976,12(2):89-92
Summary Se-Carboxymethyl-DL-selenocysteine (CMSeC) has been prepared in a pure crystalline form from selenocysteine and monochloroacetic acid. It has been shown that CMSeC is a substrate for the L-aminoacid oxidase from snake venom and for the D-aspartate oxidase from beef kidney. Oxygen consumption and ammonia production indicate that only the L or the D form of CMSeC are acted upon respectively by one or the other of the above enzymes. No noticeable differences were shown in the oxidation rate of CMSeC and S-carboxymethylcysteine, an indication that the substitution of a selenium for a sulfur atom in the molecule does not greatly affect the substrate specificity of the two enzymes. Data have been obtained suggesting that the product of the oxidative deamination of CMSeC is Se-carboxymethyl-selenopyruvic acid. 相似文献
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Antonio Rescigno Francesca Sollai Brunella Pisu Augusto Rinaldi Enrico Sanjust 《Journal of enzyme inhibition and medicinal chemistry》2013,28(4):207-218
The active site of tyrosinase is described with a view to depicting its interactions with substrates and inhibitors. Occurrence and mechanism(s) of tyrosinase-mediated browning of agrofood products are reviewed, with regard to both enzymic and chemical reactions, and their control, modulation, and inhibition. Technical and applicational implications are discussed. 相似文献
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Abstract The various stages of female gametophyte development and embryogenesis in S. spiralis and S. aestivalis are described. In both species the reproductive cycle is sexual. Some peculiarities are present: the female gametophyte is usually 6-7-8-nucleate; after double fertilization a single endospermatic cell is formed; the proembryo appears differentiated and is made up of different cells in the chalazal and micropylar ends; a single basal cell in the proembryo acts as suspensor. 相似文献