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71.
72.
Electrophoretic mobility, amino acid composition and salt dissociation of histones isolated from sperm of sea urchin Strongylocentrotus intermedius and calf thymus cells were studied. The special arginine-rich histone fraction (I) has been observed in sea urchin sperm chromatin, this fraction being absent in calf thymus chromatin. Dissociation of lysine-containing histone fractions from sea urchin chromatin occured in the range of 0.7 to 1.0 M NaCl concentrations. H1 of calf thymus chromatin was totally extracted with 0.6 M NaCl. In the course of a further increase of salt concentrations (up to 1.5 M NaCl) a practically total extraction of histones from sperm chromatin was observed, while about 20% of proteins remained bound to DNA in thymus chromatin after extraction with 2.0 M NaCl. The template activity of non-extracted DNP preparations from urchin sperm was equal to 2-3% of that of totally deproteinized DNA. The template activity of DNP gradually increased at protein extraction from DNP preparations. The hybridization capacity of RNA transcribed on partially dehistonized DNP templates in vitro also increased. 相似文献
73.
The influence of growth regulators absorbed by the root on sex expression in hemp plants 总被引:5,自引:1,他引:4
Application, through the root system, of growth regulators to hemp (Cannabis sativa L.) plants having 2–3 pairs of visible leaves caused pronounced shifts of sex expression in the adult individuals. Treatment with gibberellic acid (25 mg/l) resulted in more than 80% of the plants being male, i.e. having staminate flowers (controls, ca. 30%). Treatment with 6-benzylaminopurine and with indole-3-acetic acid (in either case, 15 mg/l) resulted in all plants being either female (pistillate flowers) or intersexes (bisexual flowers); treatment with abscisic acid (10 mg/l) had a similar but somewhat less pronounced effect. 相似文献
74.
Properties of individual ionic channels formed by polyene antibiotic Amphotericin B were studied on brain phospholipid membranes containing cholesterol. The ionic channels have a closed state and an open one (with conductance of about 6.5 pS in 2 M KCl). The conductance value of an open channel is independent of cholesterol concentration in the membrane and of pH in the range from 3.5 to 8.0. The voltage-current characteristics of a single channel are superlinear. Zero current potential value in the case of different KCl concentrations in the two solutions indicates preferential but not ideal anionic selectivity of a single channel. Channel conductivity grows as the electrolyte concentration is increased and tends to a limiting value at high concentrations. A simple model having only one site for an ion was shown to represent satisfactorily an open channel behaviour under different conditions. An individual ionic channel performs a large number of transitions between the open and closed states during its life-time of several minutes. Rate constants of these transitions depend on the kind and concentration of salt in aqueous solutions. The switching system functioning is not influenced by an ion situated inside the pore. 相似文献
75.
V A Spitsyn A G Novoradovski? A D Ispoloatov N Kh Spitsyna N R Ignatenko 《Genetika》1991,27(4):709-718
Distribution of the subtypes and gene frequencies of phosphoglucomutase-1 among some populations of Buryats, Kirghizes of the Pamir and Russians of Moscow district was analysed. The frequencies of PGM1 genes vary in Buryats being PGM1+(1) 0.647-0.743, PGM1-(1)-0.100-0.132, PGM2+(1)-0.122-0.199 and PGM2-(1)-0.007-0.037. Following frequencies of PGM1 genes were established for Kirghizes: PGM1+(1) = 0.614, PGM1-(1) = 0.114, PGM2+(1) = 0.217 and PGM2-(1) = 0.054; in Russian populations the frequencies were: PGM1+(1) = 0.578, PGM1-(1) = 0.110, PGM2+(1) = 0.253 and PGM2-(1) = 0.059. Peculiarities of PGM1 polymorphism in the USSR and all over the world were analysed. Parallel biodemographic investigations in Buryat population demonstrated differences in intensities of selection, related to concrete PGM genotypes. 相似文献
76.
Connections of the neurons of the spinal cord ventral horn with the structures, situating above have been investigated. After injection of uranyl acetate into the TIII segment of the spinal cord, labelled neurons are found in various reticular nuclei of the medulla oblongata. At the level of the roots of the XII pair of the cranial nerves they are revealed in the reticular paramedian, ventral, parvocellular and lateral nuclei. The formations mentioned participate in regulation of the cardio-vascular system. More rostral (2 and 4 mm relatively to the roots of the XII pair of the cranial nerves) the neurons are observed in the reticular giant cellular nucleus, in nuclei of the raphe and in the group of the P-substance reactive neurons. Besides, labelled neurons are revealed in the posterior, lateral fields and in the dorso- and ventromedial nuclei of the hypothalamus. 相似文献
77.
E S Pantskhava S Kh Tapaltsian E V Davidenko G L Shaposhnikov G S Kaloshina 《Prikladnaia biokhimiia i mikrobiologiia》1991,27(1):108-118
The content of 17 individual amino acids contained in nitrogen-organic matter of poultry dung was being studied in the course of the dung conversion into biogas. The concentration of organic matter and ammonium ions had no effect on the rate of the amino acid conversion, but influenced the decomposition and accumulation of individual amino acids. The intensive de novo synthesis of some amino acids was observed during methane generation of poultry dung. 相似文献
78.
Three genetic systems of blood groups of great gerbils were studied to reveal that different resistance patterns exist in rodents toward Yersinia pestis and Salmonella typhimurium. Extrapolation of the results obtained on relations of co-members of parasite systems contributes to understanding of some points of immunobiological mechanisms of dynamics of expizootic procedures. A hypothesis is proposed claiming that isoantigenic blood structure of the host is responsible for formation of population resistance to infection. 相似文献
79.
Veronika Lozhnikova J. Krekule Frideta Seidlová Tamara Bavrina M. Kh. Chailakhyan 《Biologia Plantarum》1981,23(1):36-40
Abscisic acid (ABA) was applied in a concentration of 1. 10?3 M and 1. 10?4 M to the quantitative SD plantChenopodium rubrum under various light regimes. ABA did not influence flowering in plants under continuous illumination, enhanced flowering in plants subjected to long days and inhibited it in plants induced by short days. It was concluded that ABA can not substitute for inductive treatment but its action may be additive to initial stages of reproductive morphogenesis (enhanced growth rate and branching of the apical meristem) as evoked by long days. 相似文献
80.
Nuclear translocation of cAMP-dependent protein kinase 总被引:2,自引:0,他引:2
M. V. Nesterova Kh. A. Ulmasov A. Abdukarimov A. A. Aripdzhanov E. S. Severin 《Experimental cell research》1981,132(2):367-373
A study was made of nuclear translocation of cAMP-dependent protein kinase and its subunits, as well as of the binding of these proteins to metaphase chromosomes. The CHO cell cultures were treated with 3H-labelled protein kinase and its subunits. The results indicate that cAMP-dependent protein kinase became translocated into the nucleus in a dissociated state and that the subunits have specific binding sites on chromatin. Transformation of normal mouse fibroblasts by virus SV40 interferes with the nuclear translocation of the regulatory subunit. The process is restored when the level of cAMP in the system is increased. Binding of the regulatory subunit to metaphase chromosomes of cells transformed by virus SV40 does not change. In the case of spontaneous cancer (KB cells) translocation of the regulatory subunit remains unaffected, whereas acceptance of the protein by the metaphase chromosomes is impeded. The results of this work suggest that compartmentalization of cAMP-dependent protein kinase—and particularly of its regulatory subunit—in the cell is highly significant for cellular processes. Disorders arising as a result of neoplastic transformation involve changes in nuclear translocation of the regulatory subunit and in its binding to the structural elements of the genome. 相似文献