检索结果-南通市图书馆

Immunoelectron Microscopy for Locating Calvin Cycle Enzymes in the Thylakoids of Synechocystis 6803

Molecular Plant 2009年第1期2卷 32-42页

作者： Rachna Agarwal Stefan Ortleb layashree Krishna Sainis michael melzer Molecular Biology Division Bhabha Atomic Research Center Mumbai 400085 India Structural Cell Biology Group Molecular Cell Biology Department Leibniz Institute of Plant Genetics and Crop Plant Research Correnstr. 3 Gatersleben06466 Germany

Unicellular cyanobacteria Synechocystis 6803 were fixed using high-pressure freezing （HPF） and freeze substitution without any chemical cross-linkers. Immunoelectron microscopy of these cells showed that five sequential enzymes of the Calvin cycle （phosphoriboisomerase, phosphoribulokinase, ribulose-1,5-bisphosphate carboxylase/oxygenase （RuBisCO）, 3-phosphoglyceratekinase and glyceraldehyde-3-phosphate dehydrogenase） and the catalytic portion of the chloroplast H^＋-ATP synthase （CF1） are located adjacent to the thylakoid membranes. Cell-free extracts of Synechocystis were processed by ultracentrifugation to isolate thylakoid fractions sedimenting at 40 000, 90 000, and 150 000 g. Among these, the 150 000-g fraction showed the highest linked activity of the above five sequential Calvin cycle enzymes and also the highest coordinated activity of light and dark reactions as assessed by ribose-5-phosphate （R-5-P）＋ADP dependent CO2 fixation. Immunogold labeling of this membrane fraction confirmed the presence of the above five enzymes as well as the catalytic portion of the CF1 ATP synthase. Notably, the protein A-gold labeling of the thylakoids was observed without use of chemical cross-linkers and in spite of the normal washing steps used during standard immunolabeling. The results showed that soluble Calvin cycle enzymes might be organized along the thylakoid membranes.

关键词： High-pressure freezing immunogold labeling membrane-isolation Synechocystis thylakoids.

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

PDX1.1-dependent biosynthesis of vitamin B6 protects roots from ammonium-induced oxidative stress

引用

Molecular Plant 2022年第5期15卷 820-839页

作者： Ying Liu Rodolfo A.Maniero Ricardo F.H.Giehl michael melzer Priscille Steensma Gabriel Krouk Teresa B.Fitzpatrick Nicolaus von Wirén Molecular Plant Nutrition Leibniz Institute of Plant Genetics and Crop Plant Research(IPK)Corrensstrasse 306466 GaterslebenGermany Structural Cell Biology Leibniz Institute of Plant Genetics and Crop Plant Research(IPK)Corrensstrasse 306466 GaterslebenGermany Department of Botany and Plant Biology University of Geneva1211 GenevaSwitzerland BPMP Universitéde MontpellierCNRSINRASupAgroMontpellierFrance State Key Laboratory of Crop Genetics and Germplasm Enhancement College of Resources and Environmental SciencesNanjing Agricultural UniversityNanjing 210095China

Despite serving as a major inorganic nitrogen source for plants,ammonium causes toxicity at elevated con-centrations,inhibiting root elongation early *** previous studies have shown that ammonium-inhibited root development relates to ammonium uptake and formation of reactive oxygen species(ROS)in roots,it remains unclear about the mechanisms underlying the repression of root growth and how plants cope with this inhibitory effect of *** this study,we demonstrate that ammonium-induced apo-plastic acidification co-localizes with Fe precipitation and hydrogen peroxide(H_(2)O_(2))accumulation along the stele of the elongation and differentiation zone in root tips,indicating Fe-dependent ROS *** screening ammonium sensitivity in T-DNA insertion lines of ammonium-responsive genes,we identified PDX1.1,which is upregulated by ammonium in the root stele and whose product catalyzes de novo biosyn-thesis of vitamin *** growth of pdx1.1 mutants is hypersensitive to ammonium,while chemical complementation or overexpression of PDX1.1 restores root *** salvage strategy requires non-phosphorylated forms of vitamin B6 that are able to quench ROS and rescue root growth from ammo-nium ***,these results suggest that PDX1.1-mediated synthesis of non-phosphorylated B6 vitamers acts as a primary strategy to protect roots from ammonium-dependent ROS formation.

关键词： ammonium nutrition apoplastic pH Fe mobilization root elongation pyridoxine ROS scavenging

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Reduced striatal volumes in Parkinson’s disease:a magnetic resonance imaging study

引用

Translational Neurodegeneration 2012年第1期1卷 132-139页

作者： Toni L Pitcher Tracy R melzer michael R MacAskill Charlotte F Graham Leslie Livingston Ross J Keenan Richard Watts John C Dalrymple-Alford Tim J Anderson Department of Medicine University of OtagoChristchurchNew Zealand New Zealand Brain Research Institute 66 Stewart StChristchurch 8011New Zealand Department of Psychology University of CanterburyChristchurchNew Zealand College of Medicine University of VermontBurlingtonVTUSA Christchurch Radiology Group ChristchurchNew Zealand Department of Neurology Canterbury District Health BoardChristchurchNew Zealand

Background:The presence and extent of structural changes in the brain as a consequence of Parkinson’s disease(PD)is still poorly ***:High-resolution 3-tesla T1-weighted structural magnetic resonance images in sixty-five PD and 27 age-matched healthy control participants were ***,caudate,and intracranial volumes were manually traced in the axial plane of 3D reconstructed *** nuclei volumes were normalized to intracranial volume for statistical *** status was assessed using the Unified Parkinson’s Disease Rating Scale and Hoehn and Yahr *** status was assessed using global status tests and detailed neuropsychological ***:Both caudate and putamen volumes were smaller in PD brains compared to controls after adjusting for age and *** volumes were reduced by 11%(p=0.001)and putamen volumes by 8.1%(p=0.025).PD striatal volumes were not found to be significantly correlated with cognitive or motor ***:Small,but significant reductions in the volume of both the caudate and putamen occur in PD *** reductions are independent of the effects of age and gender,however the relation of these reductions to the functional loss of dopamine,which is characteristic of PD,remains unclear.

关键词： Magnetic resonance imaging Volumetry Caudate Putamen Parkinson’s disease

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：