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1.
The role of sodium ions in amylase secretion from rat parotid cells was studied using various Na+-free media and monensin. In a sucrose medium, amylase secretion was not stimulated by isoproterenol but was significantly stimulated by dibutyryl cAMP. In choline chloride and LiCl media, both isoproterenol and dibutyryl cAMP clearly evoked amylase release. Monensin itself elicited amylase secretion slightly, but significantly inhibited the secretion stimulated by isoproterenol or dibutyryl cAMP. The inhibitory effect of monensin was detectable even in choline chloride, LiCl and KCl media. These results indicate that sodium ions are not essential for amylase secretion from rat parotid cells and that the inhibitory effect of monensin is independent of influx of sodium ions or efflux of potassium ions. 相似文献
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Takuma Tanada 《Physiologia plantarum》1984,61(1):35-37
The interactions of green or red light with blue light on the dark closing of Albizzia julibrissin Durazz. pinnules have been investigated. Irradiations at 430, 450 and 470 nm progressively delay dark closing with increasing photon fluence rates. Red or green light alone has no effect. However, when the blue fluence rate is low, both red and green light interact with it and increase the delaying effect of the blue light. When the blue fluence rate is high, green light interacts with it to negate some of the effectiveness of the blue light, while red light has no effect. This is similar to results obtained previously with far-red light. It is suggested that the same unidentified photoreceptor is operating in both the far-red and blue regions. The results also indicate the presence of a blue-only absorbing photoreceptor whose action is increased by phytochrome. 相似文献
3.
Young mung bean plants (Phaseolus mungo) were exposed to 14C-shikimateor 14C-quinate in the light. After 8 or 23.5 hr of incubationat 25°C, radioactivities in free and bound amino acids,organic acids, soluble and insoluble carbohydrates, ether-solublefraction and lignin were determined. Shikimic and quinic acidswere separated by the combined use of paper-chromatography andcolumn chromatography. Specific activity of formed quinate orshikimate was only slightly lower than that of fed shikimateor quinate. Specific activities of phenylalanine, tyrosine andbound tryptophan were high as compared with those of non-aromaticamino acids. Discussion is focused upon the interconversionbetween shikimate and quinate, and their roles in the biosynthesisof aromatic amino acids. (Received November 15, 1968; ) 相似文献
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Shoichi Asano Toshio Matsuda Kazuhiro Takuma Hye Sun Kim Tomoaki Sato Takashige Nishikawa Akemichi Baba 《Journal of neurochemistry》1995,64(6):2437-2441
Abstract: The effects of nitric oxide (NO)-generating agents on 45 Ca2+ uptake in rat brain slices and cultured rat astrocytes were studied in the presence of monensin, which is considered to drive the Na+ -Ca2+ exchanger in the reverse mode. Sodium nitroprusside (SNP) at >10 µ M increased monensin-stimulated Ca2+ uptake in the slices, although it did not affect high K+ -stimulated Ca2+ uptake. Another NO donor, 3-morpholinosydnonimine, was effective. The effect of SNP was antagonized by hemoglobin (50 µ M ), a NO scavenger, and mimicked by 8-bromo-cyclic GMP (100 µ M ). In rat brain synaptosomes, SNP increased monensin-stimulated Ca2+ uptake, but it did not affect high K+ -stimulated Ca2+ uptake. 8-Bromocyclic GMP, but not SNP, increased Na+ -dependent Ca2+ uptake significantly in synaptic membrane vesicles in the absence of monensin. In cultured rat astrocytes, SNP and 8-bromo-cyclic GMP increased Ca2+ uptake in the presence of ouabain and monensin, which were required for the Ca2+ uptake in the cells. These findings suggest that NO stimulates the Na+ -Ca2+ exchanger in neuronal preparations and astrocytes in a cyclic GMP-dependent mechanism. 相似文献
7.
There has been no report on stem nodules with nitrogen fixing activity. Aeschynomene indica produce nodules on the aerial parts, and the stem nodules proved to be capable of considerable nitrogen fixation [C2H4 produced c. 4 μmol (g fresh weight)-1 h-1]. The stem nodules embed reddish tissues, and a rod-shaped bacterium was isolated from the tissues. The bacterium was ascertained to form root and stem nodules on seedlings of A. indica. 相似文献
8.
A strain of carrot cells (Daucus carota cv. Kintoki) grew exponentially in the presence of 2,4-dichlorophenoxyacetic acid (2,4-D, 1 mg/1) with a doubling time of about 2 days. When those cells were transferred to a medium lacking 2,4-D, they continued to grow at almost the same rate for about a week. When the cells were again transferred to the auxin-free medium, the rate of cell division gradually decreased. After the cell division had ceased, cells were returned to the ordinary 2,4-D medium. A burst of cell divisions occurred after about 2 days. Timing of DNA synthesis and of mitosis suggested that the cells had been arrested at G1 phase. In a medium containing indoleacetic acid instead of 2,4-D, the auxin was rapidly degraded and the culture was similarly synchronized as in the auxin-omitted medium. 相似文献
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Application of Fluorescent Antibody for Detecting Capsular Substances in Staphylococcus aureus 总被引:2,自引:2,他引:0
K. YOSHIDA M. TAKAHASHI T. OHTOMO Y. MINEGISHI Y. ICHIMAN K. HAGA E. KONO C. L. SAN CLEMENTE 《Journal of applied microbiology》1979,46(1):147-152
A fluorescent antibody technique was developed for the determination of the capsular-type of strains of Staphylococcus aureus. It compared favourably with the method using serum-soft agar (Yoshida 1972). With the new technique, many populations of encapsulated and unencapsulated strains were investigated. Of 1421 fresh isolates of Staph. aureus , 54 were encapsulated and among these 54·8% and 48·1% were mono- and polyvalent, respectively. Capsular-type antigens A and B were found in 92·5% and 44·4% of strains respectively; capsular-types C and D were found relatively infrequently. In the other group, of unencapsulated strains, capsular-type antigen production was demonstrated in 125 out of 163 strains examined. Mono- and polyvalent capsular-types (A and B antigen producing strains) comprised 77·6% and 22·4%. respectively. In these capsular-types A and B were found in 54·4% and 62·4%, respectively: capsular-type antigen C and D producing strains were again infrequent. These results indicate that a majority of ordinary Staph . aureus strains produce capsular-type antigens although isolation of the encapsulated strains is infrequent. 相似文献