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1.
2.
Phosphatidylinositol stimulates phosphorylation of protein components I and II in rod outer segments of frog photoreceptors 总被引:3,自引:0,他引:3
We studied the effect of phosphoinositides on the phosphorylation of endogenous proteins in the soluble fraction of the frog photoreceptor rod outer segments (ROS). Phosphatidylinositol (PI) stimulated the phosphorylation of two low molecular weight proteins, components I and II (12 and 11 kDa) which are known to be the preferential substrates of the cyclic GMP (cGMP)-dependent protein kinase in the ROS. Polyphosphoinositides (PPI) specifically inhibited the PI-dependent phosphorylation of these two components. On the other hand, PPI stimulated the phosphorylation of 38, 48 and 52 kDa proteins in the absence of PI. These data suggest that PI and PPI may function in the ROS by regulating the phosphorylation of some enzymes or regulator proteins in the transduction mechanism in the ROS. 相似文献
3.
The formation of effective root nodules on a non-nodulating line (T201) of soybean (Glycine max (L.) Merr.,) was induced by a treatment with 2,4-dichlorophenoxyacetate (2,4-D). The induced nodules, inoculated with mixed Bradyrhizobium japonicum strains A1017 and IRj2101, had a normal internal structure, red in colour and the cells being filled with bacteroids. Externally, the induced nodules were of unusual shape, being paired or gourd-like in form and were attached to thickened roots. The nodules were capable of acetylene reduction (3.1–3.5 moles g-1 fresh weight nodules h-1), allowing the growth of plants with dark green leaves. 相似文献
4.
Y Sumi M A Dent D E Owen P J Seeley R J Morris 《Development (Cambridge, England)》1992,116(3):625-637
Tissue and urokinase-type plasminogen activators are serine proteases with highly restricted specificity, their best characterised role being to release the broad specificity protease plasmin from inactive plasminogen. It has frequently been suggested that these, and similar proteases, are involved in axonal growth and tissue remodelling associated with neural development. To help define what this role might be, we have studied the expression of the plasminogen activators in developing rat nervous tissue. Urokinase-type plasminogen activator mRNA is strongly expressed by many classes of neurons in peripheral and central nervous system. We have analysed its appearance in spinal cord and sensory ganglia, and found the mRNA is detectable by in situ hybridisation very early in neuronal development (by embryonic day 12.5), at a stage compatible with it playing a role in axonal or dendritic growth. Tissue plasminogen activator mRNA, on the other hand, is expressed only by cells of the floor plate in the developing nervous system, from embryonic day 10.5 and thereafter. Immunohistochemical and enzymatic analysis showed that active tissue plasminogen activator is produced by, and retained within, the floor plate. A mechanism is suggested by which high levels of tissue plasminogen activator produced by the stationary cells of the floor plate could influence the direction of growth of commissural axons as they pass through this midline structure. 相似文献
5.
Summary A highly sensitive and specific method for staining exogenous chromium and iron in tissues is described. This method is superior to conventional complex-forming methods with regard to its sensitivity and specificity for these metals. The staining reaction is based on the metalcatalysed oxidation of phenylamines. Tissue sections were incubated in a medium containing hydrogen peroxide and phenylamines, p-phenylenediamine or phenylhydrazine. Results obtained from test-tube experiments concerning the catalytic activities of metals indicated that the staining reactions depends on the activities of metals in tissues. 相似文献
6.
S Sumi K Inoue R Hosotani M Kogire R Doi M Yun S Higashide H Minote K Takaori H Kaji 《Life sciences》1990,47(13):1115-1119
The effect of intravenous administration of human epidermal growth factor on the splanchnic blood flows was examined in anesthetized dogs, using an ultrasonic transit-time volume flow meter. Human epidermal growth factor (0.1, 0.5 and 1 microgram/kg) significantly increased blood flows in the portal vein (36.9 +/- 7.4% at 1 microgram/kg) and the superior mesenteric artery (49.0 +/- 16.8% at 1 microgram/kg). Systemic blood pressure monitored simultaneously was significantly decreased (8.4 +/- 1.2% at 1 microgram/kg). This study is the first to demonstrate that intravenous administration of epidermal growth factor increases the portal venous blood flow. 相似文献
7.
Satoshi Sumi Kiyoshi Kidouchi Satoru Ohba Yoshiro Wada 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1995,672(2)
An automated screening system for purine and pyrimidine metabolism disorders using high-performance liquid chromatography (HPLC) with column switching is described. The system consists of a reversed-phase column, a cation-exchange column, a column switch, four sets of ultraviolet absorbance detectors, a microcomputer and other conventional equipment. As this system permits the simultaneous determination of urinary orotic acid, uracil, dihydrouracil, pseudouridine, xanthine, 2,8-dihydroxyadenine and succinyladenosine, it offers a useful method for the detection of orotic aciduria, dihydropyrimidine dehydrogenase deficiency, diphydropyrimidinuria, xanthinuria, adenine phosphoribosyltransferase deficiency and adenylosuccinase deficiency. 相似文献
8.
Yasuo Nagasawa Shoichiro Kurata Hiroto Komano Shunji Natori 《Development, growth & differentiation》1993,35(3):331-340
Previously, we reported autocrine involvement of Sarcophaga lectin in the development of Sarcophaga imaginal discs (Kawaguchi et al. , Dev. Biol. 144 , 86–93 (1991)). In this study, we purified Sarcophaga lectin binding protein from the membrane fraction of cultured embryonic cells of Sarcophaga to near homogeneity and raised a monoclonal antibody against it. Histochemical analysis using the monoclonal antibody revealed that this binding protein is distributed heterogeneously on the surface of leg imaginal discs. This binding protein was especially clearly localized in the central region of the basal side of leg discs which forms the junction between the leg and body, suggesting the participation of Sarcophaga lectin in morphogenesis of the basal region of the developing leg. 相似文献
9.
Possible Involvement of Phosphorylation of Occludin in Tight Junction Formation 总被引:21,自引:3,他引:18
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Akira Sakakibara Mikio Furuse Mitinori Saitou Yuhko Ando-Akatsuka Shoichiro Tsukita 《The Journal of cell biology》1997,137(6):1393-1401
Occludin is an integral membrane protein localizing at tight junctions in epithelial and endothelial cells. Occludin from confluent culture MDCK I cells resolved as several (>10) bands between 62 and 82 kD in SDS-PAGE, of which two or three bands of the lowest Mr were predominant. Among these bands, the lower predominant bands were essentially extracted with 1% NP-40, whereas the other higher Mr bands were selectively recovered in the NP-40–insoluble fraction. Alkaline phosphatase treatment converged these bands of occludin both in NP-40–soluble and -insoluble fractions into the lowest Mr band, and phosphoamino acid analyses identified phosphoserine (and phosphothreonine weakly) in the higher Mr bands of occludin. These findings indicated that phosphorylation causes an upward shift of occludin bands and that highly phosphorylated occludin resists NP-40 extraction. When cells were grown in low Ca medium, almost all occludin was NP-40 soluble. Switching from low to normal Ca medium increased the amount of NP-40–insoluble occludin within 10 min, followed by gradual upward shift of bands. This insolubilization and the band shift correlated temporally with tight junction formation detected by immunofluorescence microscopy. Furthermore, we found that the anti–chicken occludin mAb, Oc-3, did not recognize the predominant lower Mr bands of occludin (non- or less phosphorylated form) but was specific to the higher Mr bands (phosphorylated form) on immunoblotting. Immunofluorescence microscopy revealed that this mAb mainly stained the tight junction proper of intestinal epithelial cells, whereas other anti-occludin mAbs, which can recognize the predominant lower Mr bands, labeled their basolateral membranes (and the cytoplasm) as well as tight junctions. Therefore, we conclude that non- or less phosphorylated occludin is distributed on the basolateral membranes and that highly phosphorylated occludin is selectively concentrated at tight juctions as the NP-40–insoluble form. These findings suggest that the phosphorylation of occludin is a key step in tight junction assembly. 相似文献
10.
Protoplasts derived from tissue-cultured shoot primordia of garlic (Allium sativum L.) initiated successive cell divisions within 4 days and formed small individual calli (0.2mm in diameter) after 5 weeks of culture on Gamborg's B5 medium supplemented with 0.1% casein hydrolysate, 1mg/1 1-naphthaleneacetic acid and 1mg/1 6-benzylaminopurine. Plating efficiency was roughly 5% at the density of 1x104 protoplasts/ml of medium. Adventitious buds developed from the calli during subsequent subculture on Gamborg's B5 medium supplemented with 40mg/l adenine and 10% coconut milk. When transferred to the same medium without supplements, these buds grew into shoots and rooted. The regenerated garlic plantlets were successfully transferred to the greenhouse and grew into whole plants. 相似文献