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131.
The role of hypophysis in the regulation mechanism of the secretion of gut glucagon immunoreactivity (gut GI) that was measured using C-terminal specific glucagon antiserum after pancreatectomy, and gut glucagon-like immunoreactivity (gut GLI) that was obtained by subtracting GI from total glucagon-like immunoreactivity (total GLI) which was measured using non-specific glucagon antiserum, was investigated in depancreatized dogs. Plasma glucose, gut GI and gut GLI levels were found to increase in totally depancreatized dogs. The former two showed a significant decrease after hypophysectomy, and were reversed by the hypophysis-transplantation, while gut GLI was not affected either by hypophysectomy or hypophysis-transplantation. Intramuscular injections of human growth hormone (HGH) or adrenocorticotropic hormone-Z (ACTH-Z) to depancreatized-hypophysectomized dogs had no effect on plasma glucose level or gut GI. It is concluded that hypophysis may promote the secretion of gut GI after pancreatectomy, but not of gut GLI. Gut GI seems to regulate plasma glucose level after pancreatectomy. However, the precise regulation mechanism of gut GI by the hypophysial hormone after pancreatectomy is not clarified yet. 相似文献
132.
Some properties of the circadian rhythm in potassium uptakeof flow medium culture of the long-day duckweed Lemna gibbaG3 were examined.
- In total darkness, the rhythm faded out in ca. 48 hr; it restartedon transfer to continuous light. Under low-intensity light (below700 lux), the rhythm was damped rapidly
- The rhythm appearedregardless of the potassium concentrationin the culture medium(from 10/m to 2 HIM). The amplitude, butnot the period, ofthe rhythm was influenced by the ambientpotassium concentration.
- Alteration in the light intensity or medium composition causeda change in the growth rate without modifying the period ofthe rhythm.
- These results indicate that potassium uptake rhythmin thisduckweed is typical light-on rhythm, which has no directrelationwith the rate of vegetative growth and requires lightenergyfor its duration.
133.
Growth regulators were measured in extracts from the upper and lower halves of 7-mm apical segments of horizontally oriented, red-light-irradiated and non-irradiated roots of Zea mays L. cv. Golden Cross Bantam 70 which exhibit a georesponse only after an exposure to light. Abscisic acid (ABA) was measured by gas-liquid chromatography, auxin (indole-3-acetic acid, IAA) by the Avena straight-growth assay, and an unidentified growth inhibitor by a Zea root-growth assay. The ratio of ABA in the upper and lower halves was 1.6 in the irradiated roots and 1.0 in the non-irradiated ones. The total amount of ABA after irradiation was increased by a factor of ca. 1.8. The ratio of IAA in the upper and lower halves of irradiated and non-irradiated roots was 1:3.4 and 1:2.9, respectively. The content (or activity) of an unidentified growth inhibitor was highest in the lower halves of horizontally oriented roots which had been irradiated with red light. The unidentified growth inhibitor, rather than IAA or ABA, may be the major factor in the light-induced geotropic responsiveness in Zea roots. 相似文献
134.
135.
A reliable assay of uridylate sequences longer than 10 is described. The procedure is based on the hybridization of [3H]poly(A) with poly(U) or oligo(U) sequences in high ionic conditions and a subsequent degradation of single stranded polynucleotides with purified Taka-diastase. A 1:2 complex between poly(A) and poly(U) is formed on which on poly(U) strand is digested by Taka-diastase. The procedure is especially suitable for the detection and quantitation of Un (n greater than 10) in RNA preparation. 相似文献
136.
Ana Maria Andia-Waltenbaugh Charlotte A. Tate Naomi Kraus Friedmann 《Molecular and cellular biochemistry》1981,36(3):177-184
Summary Previous work by this and other laboratories has shown that glucagon administration stimulates calcium uptake by subsequently
isolated hepatic mitochondria. This stimulation of hepatic mitochondrial Ca2+ uptake byin vivo administration of glucagon was further characterized in the present report. Maximal stimulation of mitochondrial Ca2+ accumulation was achieved between 6–10 min after the intravenous injection of glucagon into intact rats. Under control conditions,
Ca2+ uptake was inhibited by the presence of Mg2+ in the incubation medium. Glucagon treatment, however, appeared to obliterate the observed inhibition by Mg2+ of mitochondrial Ca2+ uptake. Kinetic experiments revealed the usual sigmoidicity associated with initial velocity curves for mitochondrial calcium
uptake. Glucagon treatment did not alter this sigmoidal relationship. Glucagon treatment significantly increased the Vmax for Ca2+ uptake from 292±22 to 377±34 nmoles Ca2+ /min per mg protein (n=8) but did not affect the K0.5, (6.5–8.6 μM). Since the major kinetic change in mitochondrial Ca2+ uptake evoked by glucagon is an increase in Vmax, the enhancement mechanism is likely to be an increase either in the number of active transport sites available to Ca2+ or in the rate of Ca2+ carrier movement across the mitochondrial membranes. 相似文献
137.
The liberation of 2,4-dinitrophenolate ion from 2,4-dinitrophenyl sulfate (DNPS) in aqueous organic solvent with 0.1 N sodium hydroxide was accelerated upon addition of an equimolar amount of Oxime-I (10-hydroxy-11-hydroxyimino[20]-paracyclophane) to the sulfate ester. Oxime-I was found to undergo covalent participation at the oxime group to afford oxime O-sulfonate. The rate acceleration with Oxime-I was larger than that with β-CD (cycloheptaamylose). The catalytic efficiency of Oxime-I has been ascribed primarily to the tighter inclusion of the substrate ester into the more hydrophobic Oxime-I cavity provided by the effective apolar paracyclophane skeleton, as well as to the greater nucleophilicity of the oxime group than of the hydroxyl group in β-CD. Consequently, Oxime-I may be considered as a conventional model for arylsulfatases and sulfotransferases, providing the effective binding process for the substrate. 相似文献
138.
Thin sections of the spore of Bacillus thiaminolyticus Matsukawa and Misawa show a characteristic surface structure with five ridges, and a series of three district layers. The outer layer of the spore coat was peeled off by SDS sonic treatment, and than the middle layer was solubilized by alkali extraction of the SDS sonic-treated spore. The spores subjected to these treatments were still refractile, heat resistant, and contained dipicolinic acid, but lost their resistance to mechanical shock. 相似文献
139.
The potassium uptake activity of the "flow-medium culture" ofa long-day duckweed, Lemna gibba G3, followed a circadian rhythmwhich persisted for more than 5 days under continuous light.The period of the rhythm was about 25 hr under 3000 lux at 26?Cand was slightly over-compensated against temperature, Q10 beinga little less than 1.0. The amplitude of the rhythm was dependenton light intensity, and there was no potassium uptake in thedark. Magnesium uptake was affected by the potassium movementand showed circadian rhythmicity with a small amplitude underconditions where the potassium uptake was already saturated.Calcium uptake did not show any obvious rhythm. In Contrastto L. gibba, a short-day duckweed L. perpusilla 6746 displayedcircadian rhythm of potassium uptake only in the dark and notin the light. This rhythm did not persist beyond the secondcycle. (Received June 13, 1978; ) 相似文献
140.
Linkage of Mercury, Cadmium, and Arsenate and Drug Resistance in Clinical Isolates of Pseudomonas aeruginosa 总被引:10,自引:4,他引:6 下载免费PDF全文
Hideomi Nakahara Tomoaki Ishikawa Yasunaga Sarai Isamu Kondo Hiroyuki Kozukue Simon Silver 《Applied microbiology》1977,33(4):975-976
Of the 787 isolates, 99.8% were metal resistant, with most (99.5%) showing multiple resistance. Fifty-three percent of the isolates were both metal and drug resistant, whereas only 19% were metal resistant and drug sensitive. 相似文献