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41.
A membrane-associated receptor involved in a specific uptake of formaldehyde-treated serum albumin (f-Alb) was purified from rat livers by Triton X-100 solubilization of a 105,000 X g membrane preparation and affinity chromatography on an f-Alb-Sepharose column. The purified receptor exhibited Mr = 125,000, consisting of two noncovalently linked glycoprotein components with Mr = 53,000 and Mr = 30,000, respectively. Incubation of 125I-receptor with f-Alb, but not with native albumin, resulted in a marked shift of pI value from 5.9 to 5.1, reflecting the presence of a specific ligand-receptor interaction. The receptor incorporated into liposomes displayed a saturable binding to 125I-f-Alb and the binding was effectively replaced by the presence of unlabeled f-Alb, with binding parameters being similar to those obtained from 125I-f-Alb binding to the sinusoidal liver cell membrane (Horiuchi, S., Takata, K., and Morino, Y. (1985) J. Biol. Chem. 260, 475-481). Reaction of anti-f-Alb receptor antibody with extracts of sinusoidal cells resulted in a specific precipitation of two proteins whose molecular weights were identical to those for the purified receptor. The anti-receptor IgG fraction effectively blocked 125I-f-Alb binding to the sinusoidal cell membranes. These results indicate that the purified protein represents the membrane-associated receptor which is presumably involved in a specific uptake of this ligand from the circulation. 相似文献
42.
Tatsuo Nakahara Takashi Matsumoto Makoto Hirano Hideyuki Uchimura Hideyasu Yokoo Kaoru Nakamura Kenji Ishibashi Hitoshi Hirano 《Peptides》1985,6(6):1093-1099
Acute and chronic effects of γ-butyrolactone-γ-carbonyl-histidyl-prolinamide (DN-1417) were investigated on motor activity, dopamine (DA) metabolites and DA receptors in various brain regions of rats. The motor activity, as measured with Automex recorder, was enhanced after a single injection with DN-1417 (20 mg/kg, IP), and the motor stimulating action persisted during 21 daily injections. Acute DN-1417 elevated both homovanillic acid (HVA) and 3,4-dihydroxyphenylacetic acid (DOPAC) levels in 7 brain regions, prefrontal cortex polar, medial and lateral fields, nucleus accumbens, olfactory tubercles, amygdala and striatum. After chronic treatment for 7 days, the acute effect of DN-1417 on DA metabolites disappeared in all regions except for the striatum in which DN-1417 still increased HVA and DOPAC. The response of striatal DA metabolites was also observed after chronic treatment for 21 days. Chronic DN-1417 produced no significant change in 3H-spiperone binding in the prefrontal cortex, nucleus accumbens, olfactory tubercles and striatum, while striatal 3H-DA binding displaced by 30 nM spiperone was enhanced after chronic treatment. These results indicate that DN-1417 interacts with mesocortical, mesolimbic and nigrostriatal DA systems in the different modes of action. The lack of tolerance to motor hyperactivity, however, raises the question as to whether DN-1417-induced hyperactivity may be mediated by the activation of mesolimbic DA neurons. The involvement of nigrostriatal neurons in DN-1417-induced motor hyperactivity is suggested. 相似文献
43.
44.
Makoto Daimon Ken-ichi Tsutsumi Jun-ichi Sato Reiko Tsutsumi Kiichi Ishikawa 《Biochemical and biophysical research communications》1984,124(2):337-343
The expression of aldolase A and B mRNAs during azo-dye-induced carcinogenesis in rat liver was examined. After feeding the dye for 18 weeks, the level of aldolase A mRNA increased to about 11 times that in a normal liver, with the concomitant decrease of aldolase B mRNA level to about 25% of that in a normal liver. These changes did not occur progressively during the carcinogenesis, but occurred as an additional phase after 4 week-feeding of the azo-dye. At this stage, the levels of aldolase A and B mRNAs were about 7 times and 45% of that in a normal liver, respectively. This biphasic pattern in the aldolase isozyme expression in the azo-dye-fed rat liver is discussed together with the kinetic data of the enzyme activity. 相似文献
45.
4-Aminobutyraldehyde (ABAL) has been shown to cross the blood-brain barrier and to be converted rapidly to -aminobutyric acid (GABA) in various regions of the brain. In this paper, the formation of GABA from ABAL was studied with striatum that had suffered a lesion to GABA synthesis via glutamic acid decarboxylase (GAD). The GABA formation from ABAL was invariably observed in striatum in which GAD was severely inhibited by semicarbazide or kainic acid. Thus, this is another pathway for GABA formation. 相似文献
46.
Cycling of soil carbon in the first year after a clear-felling was compared with that before the felling in a Japanese red
pine forest in Hiroshima Prefecture, west Japan. The daily mean temperature at the soil surface in summer was increased after
the felling in comparison to that before felling, and the water content of both the A0 layer and the surface mineral soil was decreased due to the loss of the forest canopy. The rate of weight loss of the A0 layer was reduced after felling. However, accumulation of the A0 layer rapidly decreased because of the lack of litter supply to the forest floor. Low soil respiration after felling was
mainly caused by the cessation of root respiration. Analysis of annual soil carbon cycling was then conducted using a compartment
model. The relative decomposition rate of the A0 layer decreased whereas that of humus and dead roots in mineral soil increased to some extent after felling. The accumulation
of carbon in mineral soil, however, increased slightly due to the supply of humus from roots killed by the felling. 相似文献
47.
Five species including two new species,Araucarioxylon kiiense Ogura,Taxodioxylon albertense (Penhal.) Shimakura,Cupressinoxylon cryptomerioides Stopes,Xenoxylon watarianum sp. nov. andCedroxylon shimakurae sp. nov., were described from the Upper Cretaceous (Late Turonian-Santonian) of southern Saghalien.
Consecutive number from the previous paper (Nishida and Nishida, 1985).
Contributions from the Laboratory of Phylogenetic Botany, Chiba University No. 100. Supported by a Grant-in-Aid for Scientific
Research from the Ministry of Education, Science and Culture No. 59540441. 相似文献
48.
Makoto Hayashi Kazuko Fukushima Akihide Kitamura 《Chemistry and physics of lipids》1983,33(3):233-239
Krafft points of diacylglycerophosphocholines (PC) were measured in alkanes-cyclohexane solutions by differential scanning calorimetry, and it was found that they were regularly increased following the increase in alkane content in the solutions and the chain length of the alkanes. From these results it was deduced that the mixing of PC with alkanes occurred in the gel state of the PC, but not in micelles at higher temperatures above the Krafft points. where micellar solutions are provided. The penetration of alkanes into gel state PC was found to be dominated by Langmuir type interaction, and the affinity of alkanes increases with increasing in chain lengths. Above the Krafft points, the micelle formation was confirmed by using the fluorescence probe technique. 相似文献
49.
Summary Spectinomycin resistant (spc
r) mutants were obtained by treating the cells of E. coli K12, W3637 with nitrosoguanidine. The compositions of ribosomal proteins were analyzed for six out of eleven such spc
r-mutants with chromatography on a carboxymethyl cellulose (CMC) column. The 30s ribosomal subunit from all of the spc
r-mutants was found to contain the altered 30-4 protein component, while no difference was detected in 50s ribosomal proteins between spc
r and spc
s bacteria.Abbreviations used CMC
carboxymethyl cellulose
-
str
streptomycin
-
spc
spectinomycin 相似文献
50.
Effect of Ethanol on the Sodium and Potassium Conductances of the Squid Axon Membrane 总被引:8,自引:6,他引:2 下载免费PDF全文
The effects of ethanol on squid giant axons were studied by means of the sucrose-gap technique. The membrane action potential height is moderately reduced and the duration sometimes shortened by ethanol in sea water. Voltage clamp experiments showed that ethanol in sea water reduced the maximum membrane conductances for sodium (g'Na) and potassium (g'K). In experiments with multiple application of ethyl alcohol to the same spot of membrane, a reduction of g'Na to 82 per cent and of g'K to 80 per cent of their value in sea water was brought about by 3 per cent ethanol (by volume) while 6 per cent caused a decrease of g'Na to 59 per cent and of g'K to 69 per cent. Ethanol has no significant effect on the steady-state inactivation of gNa (as a function of conditioning membrane potential) or on such kinetic parameters as τh or the time course of turning on gi gNa and gK. It is concluded that ethanol mainly reduces gNa and gK in the Hodgkin-Huxley terminology. 相似文献