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161.
Ganglioside distribution was studied in peripheral nerves of normal controls and those of Trembler mutant mouse with defect in Schwann cell differentiation and myelination. Neuraminic acid content was considerably decreased in the mutant. Ganglioside distribution as evaluated by densitometry of resorcinol positive spots on thin-layer chromatography revealed a major peak for GDla in normal controls. In the mutant, the relative proportion was modified with qualitative modifications in the GDla area and a tremendous increase in GM3 content. The relation with the intense Schwann cell proliferation observed in the mutant is discussed. 相似文献
162.
Barry S. Cooperman Alain Expert-Bezançon Lawrence Kahan Jacques Dondon Marianne Grunberg-Manago 《Archives of biochemistry and biophysics》1981,208(2):554-562
We here report the results of using three light-dependent procedures for crosslinking IF-3 to 30 S proteins within an IF-3·30 S complex. In the first procedure, employing FMN as a photosensitizer, protein S12 is found to be the only major crosslinked protein. In the second procedure, IF-3 is first reacted with the new two-stage crosslinking reagent, p-nitrobenzylmaleimide (PNBM), and the PNBM—IF-3·30 S complex is irradiated. The major crosslinked proteins are S3 > S2, S12, S18. Small amounts of crosslinked S11 and S21 are also found. In the third procedure, the IF-3·30 S complex is reacted with PNBM and then irradiated. The major crosslinked proteins are S12 > S3 > S11 and small amounts of crosslinked S1, S13, and S21 are also found. These results are compared with results obtained by others using different crosslinking procedures and are used to discuss the Lake and Kahan model (J. A. Lake and L. Kahan, 1975, J. Mol. Biol., 99, 631–644, and J. A. Lake, 1978, in Advanced Techniques in Biological Electron Microscopy II, Koehler, J. K., ed., pp. 173–211, Springer-Verlag, Berlin) for IF-3 binding to 30 S subunits. 相似文献
163.
Suzanne Desjardins-Giasson Jolanta Gutkowska Raul Garcia Jacques Genest 《Prostaglandins & other lipid mediators》1982,24(1):105-114
Prostaglandin E2 (PGE2) and 6 keto-PGF1α, the stable metabolite of prostacyclin (PGI2), have been measured in the effluent of perfused rat mesenteric arteries by the use of a sensitive and specific radioimmunoadday (RIA) method. The PGE2 and 6-keto-PGF1α were continuousyl released by the unstimulated mesenteric artery over a period of 145 min. After 100 min of perfusion the release of PGE2 and 6-keto-PGF1α was 4.5 ± 8.4 pg/min and 254 ± 75 pg.min respectively, which is in accord with the general belief that PGI2 is the major PG synthesized by arterial tissue. Angiotensin II (AII) 5 ng/ml) induced an increased of PGE2 and 6-keto-PGF1α release without changing the perfusion pressure. The effect of norepinephrine (NE) injections on release of PGs depended on the duration of the stabilization period. The changes of perfusion pressure induced by NE were not related to changes in release of PGs. Thus, it seems that the increase of PG release induced by AII and NE was due to a direct effect of the drugs on the vascular wall. This may represent an important modulating mechanism in the regulation of vascular tone. 相似文献
164.
Stephen S. Bates Andr Tessier Peter G. C. Campbell Jacques Buffle 《Journal of phycology》1982,18(4):521-529
The amount of zinc adsorbed onto the cell surface of the unicellular green algae Scenedesmus subspicatus Hodat and Chlamydomonas variabilis Dangeard was operationally defined by extraction with EDTA; it was a function of the concentration of free ionic zinc remaining in the growth medium, rather than that of the total (free plus complexed) zinc concentration, and could be described by Langmuir isotherms. Conditional adsorption equilibrium constants for zinc were 0.123 and 0.039 L ·μmol?1 for S. subspicatus and C. variabilis, respectively. A portion of the zinc adsorbed onto C. variabilis was released into solution after 1 h of contact with the metal, providing a possible tolerance mechanism for this alga; the division rate of C. variabilis was not altered by up to 12 μmol Zn2+· L?1, although the cell yield obtained during the stationary phase was significantly decreased. The amount of transported or cellular zinc, for both algal species, was operationally defined as the zinc remaining with the cell after EDTA-extraction; it was a linear function of the free ionic zinc concentration remaining in solution, suggesting that the zinc transported into the cell was not derived from the total adsorbed fraction, although the latter may contain some zinc originating from specific sites leading to zinc transport. 相似文献
165.
A population of Laminaria longicruris de la Pylaie was followed for a year at Bic Island, Quebec, Canada where nutrient levels in the seawater were elevated throughout the year. Tagged kelp were measured each month for growth and analyzed for alginic acid, laminaran, mannitol, carbon, nitrogen, and nitrate. Maximum growth (3.5 cm · d?1) was observed in June, and minimal growth (0.18 cm · d?1) from December to February, when ice cover limited light levels. No reserves of carbon or nitrate were formed. Laminaran levels remained below 2.7% dry weight while tissue nitrate did not exceed 0.75 μmol · g?1 dry weight. Total carbon produced per plant was 40 g C · yr?1. Nutrient availability enables the kelp to take advantage of summer light and temperature conditions to grow rapidly. 相似文献
166.
Evidence for sedative effects of low doses of morphine in mice involving receptors insensitive to naloxone 总被引:1,自引:0,他引:1
Low doses of morphine (0.30–2.5 mg/kg) decrease in a dose-dependent manner spontaneous climbing behaviour in mice. This effect is not modified by administration of naloxone at doses up to 1.25 mg/kg. These morphine doses do not modify the locomotor activity but, when they are associated with naloxone (0.5 mg/kg), an obvious inhibition occurs. In rats, a hyperactivity follows the akinesia produced by a morphine administration (10 mg/kg). This hyperactivity is changed into a significant hypokinesia when the animals are treated with naloxone (0.05 mg/kg). These results might reveal a dual effect of low doses of morphine, the excitatory effect of morphine being antagonized by naloxone whereas no action on the sedative effect is observed. 相似文献
167.
First internode growth of green Vigna sinensis L. can be widely modified by light or dark treatments. In all the treatments used there is a good correlation between the internode growth and the rate of C18-1 accumulation. None of the other fatty acids show such a correlation.Abbreviations C16-0
palmitoic acid
- C17
heptadecanoic acid
- C18-0
stearic acid
- C18-1
octadecenoic acid
- C18-2
linoleic acid
- C18-3
linolenic acid
- D
darkness
- DW
dry weight
- FR
far-red light
- FW
fresh weight
- PFR
phytochrome in the FR absorbing form
- R
red light
- W
white light 相似文献
168.
The effect of Concanavalin A (Con A), or bacterial lipopolysaccharide (LPS) on mouse spleen cell populations was investigated. The membrane fluorescence changes of activated splenic lymphocytes were studied during two weeks after the injection of polyclonal immunogens. Experiments were performed with the hydrophobic fluorescent probe: 1-anilino-8-naphthalene sulphonate (ANS). The kinetic studies further indicated that the course of fluorescence changes may considerably vary depending on both immunogens. These fluorescence intensity changes would be in direct relation to the electrokinetic surface potential changes of activated lymphocytes, as assessed by the electrophoretic mobility analysis. By comparison with the inverse relationship observed in our previous study, it would be concluded that the relation (direct or inverse) between ANS fluorescence and electrokinetic potential depends on the net electrical charge of the antigens used. 相似文献
169.