Heterogeneity of biological samples is usually considered a major obstacle for three-dimensional (3D) structure determination of macromolecular complexes. Heterogeneity may occur at the level of composition or conform...Heterogeneity of biological samples is usually considered a major obstacle for three-dimensional (3D) structure determination of macromolecular complexes. Heterogeneity may occur at the level of composition or conformational variability of complexes and affects most 3D structure determination methods that rely on signal averaging. Here, an approach is described that allows sorting structural states based on a 3D statistical approach, the 3D sampling and classification (3D-SC) of 3D structures derived from single particles imaged by cryo electron microscopy (cryo-EM). The method is based on jackknifing & bootstrapping of 3D sub-ensembles and 3D multivariate statistical analysis followed by 3D classification. The robustness of the statistical sorting procedure is corroborated using model data from an RNA polymerase structure and experimental data from a ribosome complex. It allows resolving multiple states within heterogeneous complexes that thus become amendable for a structural analysis despite of their highly flexible nature. The method has important implications for high-resolution structural studies and allows describing structure ensembles to provide insights into the dynamics of multi-component macromolecular assemblies.展开更多
Multiple system atrophy (MSA) is a rapidly progressive neurodegenerative disorder characterized by a variable combination of autonomic failure, parkinsonism with poor response to levodopa, cerebellar ataxia and pyrami...Multiple system atrophy (MSA) is a rapidly progressive neurodegenerative disorder characterized by a variable combination of autonomic failure, parkinsonism with poor response to levodopa, cerebellar ataxia and pyramidal symptoms. The pathological hallmark of MSA is the oligodendrocytic glial cytoplasmic inclusions (GCIs) consisting of α-synuclein, and so MSA, together with Parkinson’s disease (PD) and dementia with Lewy bodies (DLB), is an α-synucleinopathy. Currently few effective biomarkers have been identified for the diagnosis or prognosis of MSA, and there is no established therapy to delay its progression. In this review, we discuss the epidemiology, neuropathology, genetics, clinical presentation and diagnostic biomarkers of MSA, as well as recent advances in its treatment.展开更多
Alpha-synucleinopathies(α-synucleinopathies)are a diverse group of neurodegenerative diseases comprising Parkinson’s disease(PD),dementia with Lewy bodies(DLB),and multiple system atrophy(MSA).Although in all these ...Alpha-synucleinopathies(α-synucleinopathies)are a diverse group of neurodegenerative diseases comprising Parkinson’s disease(PD),dementia with Lewy bodies(DLB),and multiple system atrophy(MSA).Although in all these diseases there exist abnormal accumulation of alpha-synuclein(α-syn)aggregates in nerve tissues,the pathological lesions formed byα-syn aggregates and their cellular locations are quite different.In PD and DLB,the hallmark pathological lesions are Lewy bodies(LBs)and Lewy neurites(LNs),which are localized in the neuronal somata and processes.In MSA,the characteristic pathologic structures are glial cytoplasmic inclusions,which are deposited in the cytoplasm of oligodendrocytes.The fact that PD and MSA have distinct pathologicalα-syn lesions suggest that different mechanisms play a role in the pathogenesis of the two diseases.In this review article,we compare the clinical manifestations and pathological features of PD and MSA,the two common synucleinopathies,and discuss the potential mechanisms for the formation ofα-syn aggregates and their pathologic roles in PD and MSA.展开更多
采用感官定量描述分析法(SQDA)对A(JA1~JA3)、B(JB1~JB3)、C(JC1~JC3)三组复合香型白酒9个样品的风味结构进行分析,结果表明:三组复合香型白酒在香气评分上差异不显著,粮香、焦香、麦芽香突出,在口感评分上差异显著,A组白酒各维度口感...采用感官定量描述分析法(SQDA)对A(JA1~JA3)、B(JB1~JB3)、C(JC1~JC3)三组复合香型白酒9个样品的风味结构进行分析,结果表明:三组复合香型白酒在香气评分上差异不显著,粮香、焦香、麦芽香突出,在口感评分上差异显著,A组白酒各维度口感评分高于其他两组。采用顶空-气相色谱质谱联用技术(HS-GC-MS)对3种白酒挥发性化合物组成进行检测分析,共检测到148种挥发性物质。相关性分析结果显示,异丁醛、3-甲基呋喃、二甲基二硫醚、巴豆酸、环氧丙烷、丙烯醛和草酸只在A组白酒中被检测出来,丁酸乙酯在B组白酒中含量最高,JA3中含量偏低,表明3组白酒样品间存在明显的风味物质种类和含量差异。同步结合特征差异代谢物分析挖掘出74个VIP>1的潜在差异代谢物,A vs B组、A vs C组、B vs C组分别有14种、7种、4种化合物呈现极显著性差异(p<0.01),这些含量具有显著差异性的化合物可能与复合香型白酒风味特征的差异具有重要联系。综上所述,本研究采用两种技术协同分析,获得了3种白酒更全面的挥发性风味信息,解析了三组复合香型白酒的风味结构特征及差异,为深入研究复合香型白酒风味形成的机理奠定了基础。展开更多
文摘Heterogeneity of biological samples is usually considered a major obstacle for three-dimensional (3D) structure determination of macromolecular complexes. Heterogeneity may occur at the level of composition or conformational variability of complexes and affects most 3D structure determination methods that rely on signal averaging. Here, an approach is described that allows sorting structural states based on a 3D statistical approach, the 3D sampling and classification (3D-SC) of 3D structures derived from single particles imaged by cryo electron microscopy (cryo-EM). The method is based on jackknifing & bootstrapping of 3D sub-ensembles and 3D multivariate statistical analysis followed by 3D classification. The robustness of the statistical sorting procedure is corroborated using model data from an RNA polymerase structure and experimental data from a ribosome complex. It allows resolving multiple states within heterogeneous complexes that thus become amendable for a structural analysis despite of their highly flexible nature. The method has important implications for high-resolution structural studies and allows describing structure ensembles to provide insights into the dynamics of multi-component macromolecular assemblies.
文摘Multiple system atrophy (MSA) is a rapidly progressive neurodegenerative disorder characterized by a variable combination of autonomic failure, parkinsonism with poor response to levodopa, cerebellar ataxia and pyramidal symptoms. The pathological hallmark of MSA is the oligodendrocytic glial cytoplasmic inclusions (GCIs) consisting of α-synuclein, and so MSA, together with Parkinson’s disease (PD) and dementia with Lewy bodies (DLB), is an α-synucleinopathy. Currently few effective biomarkers have been identified for the diagnosis or prognosis of MSA, and there is no established therapy to delay its progression. In this review, we discuss the epidemiology, neuropathology, genetics, clinical presentation and diagnostic biomarkers of MSA, as well as recent advances in its treatment.
基金the authors are supported by grants from Natural Science Foundation of China(81671244,81371200,and 81401042)a special fund from Key Laboratory of Neurodegenerative Disease,Ministry of Education(PXM2019_026283_000002)+1 种基金Beijing Municipal Science and Technology Commission(Z161100005116011,Z171100000117013)Beijing Municipal commission of Health and Family Planning(PXM2017_026283_000002).
文摘Alpha-synucleinopathies(α-synucleinopathies)are a diverse group of neurodegenerative diseases comprising Parkinson’s disease(PD),dementia with Lewy bodies(DLB),and multiple system atrophy(MSA).Although in all these diseases there exist abnormal accumulation of alpha-synuclein(α-syn)aggregates in nerve tissues,the pathological lesions formed byα-syn aggregates and their cellular locations are quite different.In PD and DLB,the hallmark pathological lesions are Lewy bodies(LBs)and Lewy neurites(LNs),which are localized in the neuronal somata and processes.In MSA,the characteristic pathologic structures are glial cytoplasmic inclusions,which are deposited in the cytoplasm of oligodendrocytes.The fact that PD and MSA have distinct pathologicalα-syn lesions suggest that different mechanisms play a role in the pathogenesis of the two diseases.In this review article,we compare the clinical manifestations and pathological features of PD and MSA,the two common synucleinopathies,and discuss the potential mechanisms for the formation ofα-syn aggregates and their pathologic roles in PD and MSA.
文摘采用感官定量描述分析法(SQDA)对A(JA1~JA3)、B(JB1~JB3)、C(JC1~JC3)三组复合香型白酒9个样品的风味结构进行分析,结果表明:三组复合香型白酒在香气评分上差异不显著,粮香、焦香、麦芽香突出,在口感评分上差异显著,A组白酒各维度口感评分高于其他两组。采用顶空-气相色谱质谱联用技术(HS-GC-MS)对3种白酒挥发性化合物组成进行检测分析,共检测到148种挥发性物质。相关性分析结果显示,异丁醛、3-甲基呋喃、二甲基二硫醚、巴豆酸、环氧丙烷、丙烯醛和草酸只在A组白酒中被检测出来,丁酸乙酯在B组白酒中含量最高,JA3中含量偏低,表明3组白酒样品间存在明显的风味物质种类和含量差异。同步结合特征差异代谢物分析挖掘出74个VIP>1的潜在差异代谢物,A vs B组、A vs C组、B vs C组分别有14种、7种、4种化合物呈现极显著性差异(p<0.01),这些含量具有显著差异性的化合物可能与复合香型白酒风味特征的差异具有重要联系。综上所述,本研究采用两种技术协同分析,获得了3种白酒更全面的挥发性风味信息,解析了三组复合香型白酒的风味结构特征及差异,为深入研究复合香型白酒风味形成的机理奠定了基础。
