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221.
Light plays an essential role in intracellular distribution of auxin efflux carrier PIN2 in Arabidopsis thaliana 总被引:1,自引:0,他引:1
Background
Light plays a key role in multiple plant developmental processes. It has been shown that root development is modulated by shoot-localized light signaling and requires shoot-derived transport of the plant hormone, auxin. However, the mechanism by which light regulates root development is not largely understood. In plants, the endogenous auxin, indole-3-acetic acid, is directionally transported by plasma-membrane (PM)-localized auxin influx and efflux carriers in transporting cells. Remarkably, the auxin efflux carrier PIN proteins exhibit asymmetric PM localization, determining the polarity of auxin transport. Similar to PM-resident receptors and transporters in animal and yeast cells, PIN proteins undergo constitutive cycling between the PM and endosomal compartments. Auxin plays multiple roles in PIN protein intracellular trafficking, inhibiting PIN2 endocytosis at some concentrations and promoting PIN2 degradation at others. However, how PIN proteins are turned over in plant cells is yet to be addressed.Methodology and Principle Findings
Using laser confocal scanning microscopy, and physiological and molecular genetic approaches, here, we show that in dark-grown seedlings, the PM localization of auxin efflux carrier PIN2 was largely reduced, and, in addition, PIN2 signal was detected in vacuolar compartments. This is in contrast to light-grown seedlings where PIN2 was predominantly PM-localized. In light-grown plants after shift to dark or to continuous red or far-red light, PIN2 also accumulated in vacuolar compartments. We show that PIN2 vacuolar targeting was derived from the PM via endocytic trafficking and inhibited by HY5-dependent light signaling. In addition, the ubiquitin 26S proteasome is involved in the process, since its inhibition by mutations in COP9 and a proteasome inhibitor MG132 impaired the process.Conclusions and Significance
Collectively, our data indicate that light plays an essential role in PIN2 intracellular trafficking, promoting PM-localization in the presence of light and, on the other hand, vacuolar targeting for protein degradation in the absence of light. Based on these results, we postulate that light regulation of root development is mediated at least in part by changes in the intracellular distribution of auxin efflux carriers, PIN proteins, in response to the light environment. 相似文献222.
Rebecca Aucott J?rn Bullwinkel Yang Yu Wei Shi Mustafa Billur Jeremy P. Brown Ursula Menzel Dimitris Kioussis Guozheng Wang Ingrid Reisert J?rg Weimer Raj K. Pandita Girdhar G. Sharma Tej K. Pandita Reinald Fundele Prim B. Singh 《The Journal of cell biology》2008,183(4):597-606
HP1 proteins are thought to be modulators of chromatin organization in all mammals, yet their exact physiological function remains unknown. In a first attempt to elucidate the function of these proteins in vivo, we disrupted the murine Cbx1 gene, which encodes the HP1-β isotype, and show that the Cbx1−/−-null mutation leads to perinatal lethality. The newborn mice succumbed to acute respiratory failure, whose likely cause is the defective development of neuromuscular junctions within the endplate of the diaphragm. We also observe aberrant cerebral cortex development in Cbx1−/− mutant brains, which have reduced proliferation of neuronal precursors, widespread cell death, and edema. In vitro cultures of neurospheres from Cbx1−/− mutant brains reveal a dramatic genomic instability. Our results demonstrate that HP1 proteins are not functionally redundant and that they are likely to regulate lineage-specific changes in heterochromatin organization. 相似文献
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224.
Increased Oxidant Stress and Decreased Antioxidant Status in Erythrocytes of Rats Fed with Zinc-deficient Diet 总被引:2,自引:0,他引:2
Taysi S Cikman O Kaya A Demircan B Gumustekin K Yilmaz A Boyuk A Keles M Akyuz M Turkeli M 《Biological trace element research》2008,123(1-3):161-167
The aim of this study was to evaluate the lipid peroxidation, nitric oxide (NO), and free radical scavenging enzyme activities in erythrocytes of zinc (Zn)-deficient rats and to investigate the relationship among these parameters in either group. Sixteen male rats with a weight of 40-50 g were used for the experiment. The rats were divided into control (n = 8) and Zn-deficient groups. At the end of the experiment, the animals were anesthetized with ketamine-HCl (Ketalar, 20 mg/kg(-1), i.p.), and the blood was collected by cardiac puncture after thoracotomy. Blood samples were collected in vacutainer tubes without and with K(3)-EDTA as anticoagulant. Erythrocyte catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GRD), glutathione-S-transferase (GST), superoxide dismutase (SOD) activities, total (enzymatic plus nonenzymatic) superoxide scavenger activity (TSSA), nonenzymatic superoxide scavenger activity (NSSA), antioxidant potential (AOP), and serum zinc (Zn) values in the Zn-deficient group were significantly lower than those of the control group, whereas NO and malondialdehyde (MDA) levels were significantly higher than those of the control group. The results show that Zn deficiency causes a decrease in antioxidant defense system and an increase in oxidative stress in erythrocyte of rats. 相似文献
225.
The present study aims to investigate the possible effects of carvacrol obtained from origanum oil upon the regenerative feature of the liver subsequent to partial hepatectomy in rats.Male Wistar Albino rats, weighing 230±30 g, were divided into three experiment groups. Group I (n=8) were used as sham operation group. Group II (n=8) were applied saline solution and hepatectomy. Carvacrol and hepatectomy (73 mg/kg) were applied to Group III (n=8). One dose of test material was injected 1 h before 68% partial hepatectomy. At the end of the experiments, blood and organs were removed. The liver regeneration rate of the rats was calculated measuring the weights of their liver before and after the hepatectomy. Hematoxylin and eosin, interleukin-6 (IL-6) and proliferating cell nuclear antigen (PCNA) treatments were applied to liver sections. Aspartate transaminase (AST), alanine transaminase (ALT), tumor necrosis factor-alpha (TNF-α) and IL-6 levels were determined in serum samples.The liver regeneration, mitotic index and PCNA index increased significantly in rats of Group III over the Group II at the 72nd hour after partial hepatectomy. Histological evaluations were also similar with these results of PCNA and mitotic indexes. In AST, ALT, TNF-α and IL-6 levels, there was no statistically significant difference.According to these results, it is concluded that carvacrol increases the liver regeneration rate. 相似文献
226.
This paper comprises the scientific justification for the Farm Constructed Wetland (FCW) Design Manual for Northern Ireland and Scotland. Moreover, this document addresses an international audience interested in applying wetland systems in the wider agricultural context. Farm constructed wetlands combine farm wastewater (predominantly farmyard runoff) treatment with landscape and biodiversity enhancements, and are a specific application and class of integrated constructed wetlands (ICW), which have wider applications in the treatment of other wastewater types such as domestic sewage. The aim of this review paper is to propose guidelines highlighting the rationale for FCW, including key water quality management and regulatory issues, important physical and biochemical wetland treatment processes, assessment techniques for characterizing potential FCW sites and discharge options to water bodies. The paper discusses universal design, construction, planting, maintenance and operation issues relevant specifically for FCW in a temperate climate, but highlights also catchment-specific requirements to protect the environment. 相似文献
227.
The methanolic extracts of Lactarius deterrimus, Suillus collitinus, Boletus edulis, Xerocomus chrysenteron were analyzed for their antioxidant activities in different test systems namely beta-carotene/linoleic acid, DPPH free radical scavenging, reducing power and metal chelating activities in addition to their total phenolic and flavonoid contents. In beta-carotene/linoleic acid and DPPH systems, L. deterrimus and B. edulis showed the strongest activity patterns. Their activities were as strong as the positive controls. The reducing power of the species was excellent. Chelating capacity of the extracts was increased with the increasing concentration. On the other hand, B. edulis found to have the highest phenolic content. Total flavonoid content of S. collitinus found the superior to the other mushrooms. 相似文献
228.
Effect of Strontium Ranelate on Hydrogen Peroxide-Induced Apoptosis of CRL-11372 Cells 总被引:2,自引:0,他引:2
Senkoylu A Yilmaz A Ergun MA Ilhan MN Simsek A Altun N Bolukbasi S Menevse S 《Biochemical genetics》2008,46(3-4):197-205
In vitro and in vivo studies have proven strontium to be an osteoinductive trace element. The effect of strontium ranelate
(SR) on H2O2-induced apoptosis of CRL-11372 cells and optimization of its anti-apoptotic dose were the aims of this study. After 1 h of
pretreatment with SR 1 μM, 50 μM, 100 μM, 500 μM, and 1,000 μM concentrations, CRL-11372 osteoblasts were exposed to 100 μM H2O2 for periods of 6–12 h. The same experiments were repeated without H2O2. The apoptotic index and viability of cells were assessed quantitatively with a fluorescent dye and qualitatively with agarose
gel electrophoresis. Concentrations of 1–100 μM of SR with a 6-h treatment and only 1 μM concentration with a 12-h treatment
inhibited the apoptotic effect of H2O2 on cultured osteoblasts significantly (P < 0.05). SR was shown to inhibit H2O2-induced apoptosis of CRL-11372 cells in a dose-dependent manner. 相似文献
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