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41.
Dorothy E. Pumo Ryszard Wierzbicki Adrienne Sainten Jen-Fu Chiu 《Molecular and cellular biochemistry》1980,32(1):49-53
Summary Specific antisera were produced against chicken reticulocyte dehistonized chromatin. The antisera reacts strongly with chicken reticulocyte chromatin, but only marginally with chicken erythrocyte chromatin. There is no reticulocyte antigen detected in chicken liver. Reticulocyte maturation is accompanied by a gradual decrease in the chromatin immunological activity and template capacity. The reduction of immunological activity is due to the change of chromatin conformation during erythrocyte maturation. Dehistonization and sonication of erythrocyte chromatin raises the erythrocyte chromatin immunological activity to levels similar to those of reticulocyte chromatin. The erythrocyte nuclear antigens are class specific, not being found in frog erythroid cell or murine Friend leukemia cell chromatins. 相似文献
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43.
Summary The sexual development of 14 girls with non-mosaic monocentric 46,X,iXq karyotype was studied. Seven out of eight girls were found to have immature secondary sexual characteristics and amenorrhoea, a finding greatly contrasting with that in Triplo-X girls. The relative ineffectiveness of the isochromosome Xq in maintaining fertility may be due to the absence of one short arm, which probably also carries a gonadal determinant. Alternatively, the presence of two inactivation sites on one isochromosome may render the gonadal determinants inactive at an important stage in gonadal development. 相似文献
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45.
A two-dimensionally large and thin crystal has been obtained from gp321I, a proteolytically digested product of a DNA helix-destabilizing protein coded by gene 32 in bacteriophage T4. High-resolution electron diffraction patterns (~3.7Å) are recorded from both unstained and stained protein crystals embedded in glucose. The crystal is of orthorhombic space group with . 相似文献
46.
R C Briggs J F Chiu L S Hnilica F Chytil L W Rogers D L Page 《Cell differentiation》1978,7(6):313-323
Non-histone protein-DNA complexes isolated from human lung tissue were used to immunize New Zealand rabbits. Quantitative microcomplement fixation and immunocytochemistry revealed a specific chromatin antigen(s) in the human granulocyte nucleus. The study demonstrates the feasibility of employing antisera against chromosomal non-histone protein-DNA complexes for the immunochemical identification of cell types. 相似文献
47.
Richard Hammerschlag Charles Bakhit Arlene Y. Chiu Anant R. Dravid 《Developmental neurobiology》1977,8(5):439-451
Fast axonal transport of [3H]protein has been examined in bullfrog primary afferent neurons incubated in media supplemented with divalent cations that can act as agonists or antagonists of calcium ions. Incubation in calcium-free medium (CFM) had no effect on the rate of transport, but reduced the amount of transported [3H]protein by 40–60% relative to transport in the contralateral preparation maintained in normal medium. Preparations incubated in CFM supplemented with 1.8 mM SrCl2 (equimolar to the CaCl2 concentration in normal medium) carried out transport at control levels. Incubation conditions in which primary afferent somata were exposed to the Sr2+-medium while nerve trunks were maintained in CFM also supported normal transport. By contrast, selective exposure of nerve trunks to Sr2+-medium, and somata to CFM resulted in a reduced level of transport similar to that observed when the whole preparation was incubated in CFM. The depression of transport resulting from incubation in CFM was shown to be reversible when preparations were transferred from CFM to either Sr2+-supplemented CFM or to normal medium. By contrast to the effects of Sr2+, Ba2+ (up to 18 mM) did not substitute for Ca2+ in the transport process. When normal medium was supplemented with calciumantagonist cations, the amount of transport was depressed (Co2+ > Mn2+ >> Mg2+), with no concomitant effect on the rate of transport. Results of studies with Co2+, as well as those with Sr2+, suggest that a major locus of action of these cations is within the neuronal soma at a step subsequent to protein synthesis, and prior to the onset of protein translocation via the transport system. Thus, it is inferred that these divalent cations affect a calcium-dependent step that occurs during the initiation phase of fast axonal transport. 相似文献
48.
The passive mechanical properties of myocardium were defined by measuring force responses to rapid length ramps applied to unstimulated cat papillary muscles. The immediate force changes following these ramps recovered partially to their initial value, suggesting a series combination of viscous element and spring. Because the stretched muscle can bear force at rest, the viscous element must be in parallel with an additional spring. The instantaneous extension-force curves measured at different lengths were nonlinear, and could be made to superimpose by a simple horizontal shift. This finding suggests that the same spring was being measured at each length, and that this spring was in series with both the viscous element and its parallel spring (Voigt configuration), so that the parallel spring is held nearly rigid by the viscous element during rapid steps. The series spring in the passive muscle could account for most of the series elastic recoil in the active muscle, suggesting that the same spring is in series with both the contractile elements and the viscous element. It is postulated that the viscous element might be coupled to the contractile elements by a compliance, so that the load imposed on the contractile elements by the passive structures is viscoelastic rather than purely viscous. Such a viscoelastic load would give the muscle a length-independent, early diastolic restoring force. The possibility is discussed that the length-independent restoring force would allow some of the energy liberated during active shortening to be stored and released during relaxation. 相似文献
49.
Pei-Lu Chiu Peter P. Fu Shen K. Yang 《Biochemical and biophysical research communications》1982,106(4):1405-1411
-3,4-, 5,6-, 8,9-, and 10,11-dihydrodiols formed from the metabolism of 7-fluorobenz[a]anthracene by rat liver microsomes were isolated by reversed-phase high performance liquid chromatography. Ultraviolet absorption, mass, and NMR spectral analyses indicated that the 5,6- and 8,9-dihydrodiols were preferentially in quasi-diaxial conformations, whereas the 3,4- and 10,11-dihydrodiols were preferentially in quasi-diequatorial conformations. CPK space-filling models suggest that the quasi-diaxial conformation is primarily the result of electronic repulsion between the fluorine and the hydroxyl oxygen. These findings provide a structural basis in the interpretation of the carcinogenic potencies of some fluorinated polycyclic aromatic hydrocarbons. 相似文献
50.
Albert K.B. Chiu Mukund K. Gurjar Leslie Hough Lee V. Sincharoenkul Anthony C. Richardson 《Carbohydrate research》1982,100(1):247-261
1′-O-Mesyl-6,6′-di-O-tritylsucrose and the corresponding 1′-O-tosyl derivative were prepared from 6,6′-di-O-tritylsucrose by selective sulphonylation. Both sulphonates underwent intramolecular cyclisation reactions, to give 2,1′-anhydrosucrose in high yields rather than the isomeric 1′,4′-anhydride. Sequential benzoylation, detritylation, and mesylation of the 2,1′-anhydride afforded 2,1′-anhydro-6,6′-di-O-mesylsucrose tetrabenzoate which, in the presence of base, gave 2,1′:3,6:3′,6′-trianhydrosucrose that was not identical with the product previously claimed to have this structure. Several derivatives of 2,1′-anhydrosucrose were prepared possessing different functional groups at either the 6,6′- or 4,6′-positions. Dimolar mesitylene-sulphonylation of 3,3′,4′6′-tetra-O-acetylsucrose gave the 6,1′-disulphonate, which, in the presence of alkali, gave 2,1′:3,6-dianhydrosucrose, which was transformed into the 2,1′:3,6:3′,6′-trianhydride by sequential bromination at C-6′ (carbon tetrabromide-triphenylphosphine) and base-catalysed cyclisation. Treatment of 3,3′,4′,6′-tetra-O-benzoylsucrose with sulphuryl chloride furnished the 4,6,1′-trichloro derivative, which, on alkaline hydrolysis, was converted into 2,1′:3,6-dianhydro-4-chloro-4-deoxy-galacto-sucrose. 相似文献