저자는 전체 프로토콜을 확립하기 위해 도움 예일 대학에서 초기 프로토콜과 왕 실험실의 구성원 확립 도움 UC 버클리에서 노갈레즈 실험실의 구성원을 감사드립니다. 우리는 또한 그들의 지원에 대한 의학의 예일 학교 cryo - EM 시설 및 고성능 계산 센터에서 직원을 인정합니다. HW는 스미스 가족 Awardee입니다.

<ol>
	<li>van Heel, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Angular+reconstitution:+a+posteriori+assignment+of+projection+directions+for+3D+reconstruction.">Angular reconstitution: a posteriori assignment of projection directions for 3D reconstruction.</a> Ultramicroscopy. 21, 111-123 (1987).</li><li>Radermacher, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Three-dimensional+reconstruction+of+single+particles+from+random+and+nonrandom+tilt+series.">Three-dimensional reconstruction of single particles from random and nonrandom tilt series.</a> J Electron Microsc Tech. 9, 359-394 (1988).</li><li>Penczek, P. A., Grassucci, R. A., Frank, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+ribosome+at+improved+resolution:+new+techniques+for+merging+and+orientation+refinement+in+3D+cryo-electron+microscopy+of+biological+particles.">The ribosome at improved resolution: new techniques for merging and orientation refinement in 3D cryo-electron microscopy of biological particles.</a> Ultramicroscopy. 53, 251-270 (1994).</li><li>Ohi, M., Li, Y., Cheng, Y., Walz, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Negative+staining+and+image+classification+-+powerful+tools+in+modern+electron+microscopy.">Negative staining and image classification - powerful tools in modern electron microscopy.</a> Biol Proced Online. 6, 23-34 (2004).</li><li>Frank, J., Radermacher, M., Penczek, P., Zhu, J., Li, Y., Ladjadj, M., Leith, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=SPIDER+and+WEB:+processing+and+visualization+of+images+in+3D+electron+microscopy+and+related+fields.">SPIDER and WEB: processing and visualization of images in 3D electron microscopy and related fields.</a> J Struct Biol. 116, 190-199 (1996).</li><li>Shaikh, T. R., Gao, H., Baxter, W. T., Asturias, F. J., Boisset, N., Leith, A., Frank, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=SPIDER+image+processing+for+single+particle+reconstruction+of+biological+macromolecules+from+electron+micrographs.">SPIDER image processing for single particle reconstruction of biological macromolecules from electron micrographs.</a> Nat Protoc. 3, 1941-1974 (2008).</li><li>Heel, M. v. a. n., Harauz, G., Orlova, E. V., Schmidt, R., Schatz, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+generation+of+the+IMAGIC+image+processing+system.">A new generation of the IMAGIC image processing system.</a> J Struct Biol. 116, 17-24 (1996).</li><li>Ludtke, S. J., Baldwin, P. R., Chiu, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=EMAN:+semiautomated+software+for+high-resolution+single-particle+reconstructions.">EMAN: semiautomated software for high-resolution single-particle reconstructions.</a> J Struct Biol. 128, 82-97 (1999).</li><li>Pettersen, E. F., Goddard, T. D., Huang, C. C., Couch, G. S., Greenblatt, D. M., Meng, E. C., Ferrin, T. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=UCSF+Chimera--a+visualization+system+for+exploratory+research+and+analysis.">UCSF Chimera--a visualization system for exploratory research and analysis.</a> J Comput Chem. 25, 1605-1612 (2004).</li><li>Wang, H. W., Wang, J., Ding, F., Callahan, K., Bratkowski, M. A., Buttler, J. S., Nogales, E., Ke, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Architecture+of+the+yeast+Rrp44+exosome+complex+suggests+routes+of+RNA+recruitment+for+3'+end+processing.">Architecture of the yeast Rrp44 exosome complex suggests routes of RNA recruitment for 3' end processing.</a> Proc Natl Acad Sci USA. 104, 16844-16849 (2007).</li><li>Scheres, S. H., Nunez-Ramirez, R., Sorzano, C. O., Carazo, J. M., Marabini, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Image+processing+for+electron+microscopy+single-particle+analysis+using+Xmipp.">Image processing for electron microscopy single-particle analysis using Xmipp.</a> Nat Protoc. 3, 977-990 (2008).</li><li>Yoshioka, C., Pulokas, J., Fellmann, D., Potter, C. S., Milligan, R. A., Carragher, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Automation+of+random+conical+tilt+and+orthogonal+tilt+data+collection+using+feature-based+correlation.">Automation of random conical tilt and orthogonal tilt data collection using feature-based correlation.</a> J Struct Biol. 159, 335-346 (2007).</li></ol>

관심 없음 충돌 선언하지 않습니다.

이 문서에서 우리는 샘플 준비 상세한 프로토콜과 부정적인 얼룩의 전자 현미경을 사용하여 exosome 복잡한 세 차원 재건을 제시. 이 방법을 사용하여, 우리는 구조의 어떤 사전 지식없이 임의의 원뿔 기울기 방법을 사용하여 3D 재건을 획득하였습니다. 랜덤 원뿔 틸트 방식은 반드시 단일 샘플을 필요로하지 않습니다 그러나 다음과 같은 투영 일치 상세 검색 단계는 높은 해상도를 달성하기 위해서...

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<td>Polyvinyl Formal Resin</td>
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single particle electron microscopy reconstruction of the exosome complex using the random conical tilt method

단일 입자 전자 현미경 (EM)이 재건 최근 대형 macromolecular의 단지의 3 차원 (3D) 구조를 얻을 수있는 인기있는 도구가되었습니다. X - 선 crystallography에 비해 몇 가지 독특한 장점이 있습니다. 첫째, 단일 입자 EM 재건 특히 대형 macromolecular의 단지에 대해, X - 레이 crystallography에 병목있는 단백질 샘플을 구체화 필요가 없습니다. 둘째, 그것은 단백질 샘플을 다량 필요하지 않습니다. 결정에 필요한 단백질의 밀리그램에 비해, 단일 입자 EM 재건은 부정적인 얼룩 EM 방법을 사용하여 나노 어금니 농도에서 단백질 솔루션의 몇 마이크로 리터 필요합니다. 그러나, 높은 대칭과 함께 몇 macromolecular 어셈블리에도 불구하고, 하나의 입자는 EM은 특히 이러한 대칭없이 많은 표본에 대한 (하단보다 1 나노미터 해상도) 상대적으로 낮은 해상도로 제한됩니다. 이 방법도 연구에서 분자의 크기에 의해 제한, 일반적으로 냉동 수산화 표본에 대한 부정적인 스테인드 표본 300 KDA에 대한 즉, 100 KDA. 알 수없는 구조의 새로운 샘플의 경우, 우리는 일반적으로 부정적인 얼룩으로 분자를 포함하는 중금속 솔루션을 사용합니다. 표본은 다음 분자의 2 차원 (2D) micrographs을 위해 전송 전자 현미경으로 검사합니다. 이상적으로, 단백질 분자가 단일 차원 구조를 가지고 있지만 micrographs 다른 방향을 나타냅니다. 이러한 micrographs은 &quot;단일 입자&quot;로 디지털 및 컴퓨터에서 처리됩니다. 2 차원 배열과 분류 기법을 사용하여 같은 전망에 균일한 분자는 클래스로 클러스터된 수 있습니다. 그들의 평균 분자의 2 차원 형태의 신호를 향상시킬 수 있습니다. 우리가 적절한 상호 표정 (오일러 각도)와 입자를 지정 후, 우리는 3 차원 가상 볼륨에 2D 입자 이미지를 재구 성할 수있게 될 것입니다. 단일 입자 3 차원 재건에 필수적인 단계가 제대로 각 단일 입자의 적절한 방향을 지정하는 것입니다. 각도 reconstitution 1 임의의 원뿔 기울기 (RCT) 방법 2를 포함하여, 각 입자에 대한보기를 할당하는 방법은 여러 가지가 있습니다. 이 프로토콜에서는, 우리는 부정적인 얼룩 EM와 RCT를 사용하여 효모 exosome 복합 3D 재건을 얻는 우리의 연습을 설명합니다. 이것은 전자 현미경 및 이미지 프로세싱 우리의 프로토콜 RCT의 기본 원칙을 다음 있지만 방법을 수행할 수있는 유일한 방법은 아니라는 것을 주목하여야한다. 우리가 먼저 지속적인 얇은 탄소 필름 층으로 덮여 홀리 탄소 격자를 사용하여 단백질의 크기에 비해 두께 Uranyl - 편대의 계층에 단백질 샘플을 포함하는 방법에 대해 설명합니다. 그러면 표본을 수집 전송 전자 현미경에 삽입 untilted (0 급) 및 처리와 효모 exosome의 초기 3D 모델을 얻기 위해 나중에 사용됩니다 micrographs의 기울어진 (55 급) 쌍. 이를 위해, 우리는 RCT을 수행하고 다음 상세 검색 방법 3 일치 투영을 사용하여 초기 3D 모델을 수정하십시오.

Watch this Scientific Journal Video about Single Particle Electron Microscopy Reconstruction of the Exosome Complex Using the Random Conical Tilt Method at JoVE.com

Single Particle Electron Microscopy Reconstruction of the Exosome Complex Using the Random Conical Tilt Method

이 문서는 부정적인 얼룩의 전자 현미경을 (EM)을 사용하여 생물 학적 macromolecules의 3 차원 (3D) 재건을하는 표준 방법을 설명합니다. 이 프로토콜에서는, 우리는 임의의 원뿔 기울기 재건 방법 (RCT)을 사용하여 중간 해상도 Saccharomyces cerevisiae의 exosome의 복합의 3D 구조를 얻는 방법을 설명합니다.

랜덤 코니컬 틸트 메서드를 사용하여 Exosome 단지의 단일 입자의 전자 현미경의 재건

Single particle electron microscopy (EM) reconstruction has recently become a popular tool to get the three-dimensional (3D) structure of large ...

single-particle-electron-microscopy-reconstruction-exosome-complex

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Biology

23.4K 조회수.  Yale University. 이 문서는 부정적인 얼룩의 전자 현미경을 (EM)을 사용하여 생물 학적 macromolecules의 3 차원 (3D) 재건을하는 표준 방법을 설명합니다. 이 프로토콜에서는, 우리는 임의의 원뿔 기울기 재건 방법 (RCT)을 사용하여 중간 해상도 Saccharomyces cerevisiae의 exosome의 복합의 3D 구조를 얻는 방법을 설명합니다.

비디오: Single Particle Electron Microscopy Reconstruction of the Exosome Complex Using the Random Conical Tilt Method

Method for Measurement of Viral Fusion Kinetics at the Single Particle Level

Membrane fusion is an essential step during entry of enveloped viruses into cells. Conventional fusion assays typically report on a large number of fusion events, making it difficult to quantitatively analyze the sequence of the molecular steps involved. We have developed an in vitro, two-color fluorescence assay to monitor kinetics of single virus particles fusing with a target bilayer on an essentially fluid support.
Influenza viral particles are incubated with a green lipophilic fluorophore to stain the membrane and a red hydrophilic fluorophore to stain the viral interior. We deposit a ganglioside-containing lipid bilayer on the dextran-functionilized glass surface of a flow cell, incubate the viral particles on the planar bilayer and image the fluorescence of a 100 x 100 &mu;m2 area, containing several hundreds of particles, on a CCD camera. By imaging both the red and green fluorescence, we can simultaneously monitor the behavior of the membrane dye (green) and the aqueous content (red) of the particles.
Upon lowering the pH to a value below the fusion pH, the particles will fuse with the membrane. Hemifusion, the merging of the outer leaflet of the viral membrane with the outer leaflet of the target membrane, will be visible as a sudden change in the green fluorescence of a particle. Upon the subsequent fusion of the two remaining distal leaflets a pore will be formed and the red-emitting fluorophore in the viral particle will be released under the target membrane. This event will give rise to a decrease of the red fluorescence of individual particles. Finally, the integrated fluorescence from a pH-sensitive fluorophore that is embedded in the target membrane reports on the exact time of the pH drop.
From the three fluorescence-time traces, all the important events (pH drop, lipid mixing upon hemifusion, content mixing upon pore formation) can now be extracted in a straightforward manner and for every particle individually. By collecting the elapsed times for the various transitions for many individual particles in histograms, we can determine the lifetimes of the corresponding intermediates. Even hidden intermediates that do not have a direct fluorescent observable can be visualized directly from these histograms.

We present an in vitro, two-color fluorescence assay to visualize the fusion of single virus particles with a fluid target bilayer. By labeling viral particles with fluorophores that differentially stain the viral membrane and its interior, we are able to monitor the kinetics of hemifusion and pore formation.

단일 입자 수준에서 바이러스성 퓨전 속도론의 측정 방법

Membrane fusion is an essential step during entry of enveloped viruses into cells. Conventional fusion assays typically report on a large number of fusion ...

연구

생물학

Open-source Single-particle Analysis for Super-resolution Microscopy with VirusMapper

Super-resolution fluorescence microscopy is currently revolutionizing cell biology research. Its capacity to break the resolution limit of around 300 nm allows for the routine imaging of nanoscale biological complexes and processes. This increase in resolution also means that methods popular in electron microscopy, such as single-particle analysis, can readily be applied to super-resolution fluorescence microscopy. By combining this analytical approach with super-resolution optical imaging, it becomes possible to take advantage of the molecule-specific labeling capacity of fluorescence microscopy to generate structural maps of molecular elements within a metastable structure. To this end, we have developed a novel algorithm &#8212; VirusMapper &#8212; packaged as an easy-to-use, high-performance, and high-throughput ImageJ plugin. This article presents an in-depth guide to this software, showcasing its ability to uncover novel structural features in biological molecular complexes. Here, we present how to assemble compatible data and provide a step-by-step protocol on how to use this algorithm to apply single-particle analysis to super-resolution images.

This manuscript uses the Fiji-based open-source software package VirusMapper to apply single-particle analysis to super-resolution microscopy images in order to generate precise models of nanoscale structure.

VirusMapper 슈퍼 해상도 현미경을위한 오픈 소스 단일 입자 분석

Super-resolution fluorescence microscopy is currently revolutionizing cell biology research. Its capacity to break the resolution limit of around 300 nm ...

Investigating the Detrimental Effects of Low Pressure Plasma Sterilization on the Survival of Bacillus subtilis Spores Using Live Cell Microscopy

Plasma sterilization is a promising alternative to conventional sterilization methods for industrial, clinical, and spaceflight purposes. Low pressure plasma (LPP) discharges contain a broad spectrum of active species, which lead to rapid microbial inactivation. To study the efficiency and mechanisms of sterilization by LPP, we use spores of the test organism Bacillus subtilis because of their extraordinary resistance against conventional sterilization procedures. We describe the production of B. subtilis spore monolayers, the sterilization process by low pressure plasma in a double inductively coupled plasma reactor, the characterization of spore morphology using scanning electron microscopy (SEM), and the analysis of germination and outgrowth of spores by live cell microscopy. A major target of plasma species is genomic material (DNA) and repair of plasma-induced DNA lesions upon spore revival is crucial for survival of the organism. Here, we study the germination capacity of spores and the role of DNA repair during spore germination and outgrowth after treatment with LPP by tracking fluorescently-labelled DNA repair proteins (RecA) with time-resolved confocal fluorescence microscopy. Treated and untreated spore monolayers are activated for germination and visualized with an inverted confocal live cell microscope over time to follow the reaction of individual spores. Our observations reveal that the fraction of germinating and outgrowing spores is dependent on the duration of LPP-treatment reaching a minimum after 120 s. RecA-YFP (yellow fluorescence protein) fluorescence was detected only in few spores and developed in all outgrowing cells with a slight elevation in LPP-treated spores. Moreover, some of the vegetative bacteria derived from LPP-treated spores showed an increase in cytoplasm and tended to lyse. The described methods for analysis of individual spores could be exemplary for the study of other aspects of spore germination and outgrowth.

Investigating the Detrimental Effects of Low Pressure Plasma Sterilization on the Survival of Bacillus subtilis Spores Using Live Cell Microscopy

This protocol illustrates the important consecutive steps required to assess the relevance of monitoring vitality parameter and DNA repair processes in reviving Bacillus subtilis spores after treatment with low pressure plasma by tracking fluorescence-labelled DNA repair proteins via time-resolved confocal microscopy and scanning electron microscopy.

해로운 효과의 낮은 압력 플라즈마 살 균 새 균의 subtilis 포자를 사용 하 여 라이브 셀 현미경의 생존에 조사

Plasma sterilization is a promising alternative to conventional sterilization methods for industrial, clinical, and spaceflight purposes. Low pressure ...

Isolation and Fluorescence Imaging for Single-particle Reconstruction of Chlamydomonas Centrioles

Centrioles are large macromolecular assemblies important for the proper execution of fundamental cell biological processes such as cell division, cell motility, or cell signaling. The green algae Chlamydomonas reinhardtii has proven to be an insightful model in the study of centriole architecture, function, and protein composition. Despite great advances toward understanding centriolar architecture, one of the current challenges is to determine the precise localization of centriolar components within structural regions of the centriole in order to better understand their role in centriole biogenesis. A major limitation lies in the resolution of fluorescence microscopy, which complicates the interpretation of protein localization in this organelle with dimensions close to the diffraction limit. To tackle this question, we are providing a method to purify and image a large number of C. reinhardtii centrioles with different orientations using super-resolution microscopy. This technique allows further processing of data through fluorescent single-particle averaging (Fluo-SPA) owing to the large number of centrioles acquired. Fluo-SPA generates averages of stained C. reinhardtii centrioles in different orientations, thus facilitating the localization of distinct proteins in centriolar sub-regions. Importantly, this method can be applied to image centrioles from other species or other large macromolecular assemblies.

Isolation and Fluorescence Imaging for Single-particle Reconstruction of Chlamydomonas Centrioles

We have developed a strategy to purify and image a large number of centrioles in different orientations amenable for super-resolution microscopy and single-particle averaging.

절연 및 Chlamydomonas Centrioles의 단일 입자 재건을 위한 형광 이미징

Centrioles are large macromolecular assemblies important for the proper execution of fundamental cell biological processes such as cell division, cell ...

Biological Sample Preparation by High-pressure Freezing, Microwave-assisted Contrast Enhancement, and Minimal Resin Embedding for Volume Imaging

The described sample preparation technique is designed to combine the best quality of ultrastructural preservation with the most suitable contrast for the imaging modality in a focused ion beam scanning electron microscope (FIB-SEM), which is used to obtain stacks of sequential images for 3D reconstruction and modelling. High-pressure freezing (HPF) allows close to native structural preservation, but the subsequent freeze substitution often does not provide sufficient contrast, especially for a bigger specimen, which is needed for high-quality imaging in the SEM required for 3D reconstruction. Therefore, in this protocol, after the freeze substitution, additional contrasting steps are carried out at room temperature. Although these steps are performed in a microwave, it is also possible to follow traditional bench processing, which requires longer incubation times.The subsequent embedding in minimal amounts of resin allows for faster and more precise targeting and preparation inside the FIB-SEM. This protocol is especially useful for samples that require preparation by high-pressure freezing for a reliable ultrastructural preservation but do not gain enough contrast during the freeze substitution for volume imaging using FIB-SEM. In combination with the minimal resin embedding, this protocol provides an efficient workflow for the acquisition of high-quality volume data.

Here we present a protocol for combining two sample processing techniques, high-pressure freezing and microwave-assisted sample processing, followed by minimal resin embedding for acquiring data with a focused ion beam scanning electron microscope (FIB-SEM). This is demonstrated using a mouse tibial nerve sample and Caenorhabditis elegans.

고압 냉동, 전자 레인지를 이용한 콘트라스트 향상, 그리고 볼륨 이미지에 대 한 포함 하는 최소한의 수 지에 의해 생물학 견본 준비

The described sample preparation technique is designed to combine the best quality of ultrastructural preservation with the most suitable contrast for the ...

The CryoAPEX Method for Electron Microscopy Analysis of Membrane Protein Localization Within Ultrastructurally-Preserved Cells

Key cellular events like signal transduction and membrane trafficking rely on proper protein location within cellular compartments. Understanding precise subcellular localization of proteins is thus important for answering many biological questions. The quest for a robust label to identify protein localization combined with adequate cellular preservation and staining has been historically challenging. Recent advances in electron microscopy (EM) imaging have led to the development of many methods and strategies to increase cellular preservation and label target proteins. A relatively new peroxidase-based genetic tag, APEX2, is a promising leader in cloneable EM-active tags. Sample preparation for transmission electron microscopy (TEM) has also advanced in recent years with the advent of cryofixation by high pressure freezing (HPF) and low-temperature dehydration and staining via freeze substitution (FS). HPF and FS provide excellent preservation of cellular ultrastructure for TEM imaging, second only to direct cryo-imaging of vitreous samples. Here we present a protocol for the cryoAPEX method, which combines the use of the APEX2 tag with HPF and FS. In this protocol, a protein of interest is tagged with APEX2, followed by chemical fixation and the peroxidase reaction. In place of traditional staining and alcohol dehydration at room temperature, the sample is cryofixed and undergoes dehydration and staining at low temperature via FS. Using cryoAPEX, not only can a protein of interest be identified within subcellular compartments, but also additional information can be resolved with respect to its topology within a structurally preserved membrane. We show that this method can provide high enough resolution to decipher protein distribution patterns within an organelle lumen, and to distinguish the compartmentalization of a protein within one organelle in close proximity to other unlabeled organelles. Further, cryoAPEX is procedurally straightforward and amenable to cells grown in tissue culture. It is no more technically challenging than typical cryofixation and freeze substitution methods. CryoAPEX is widely applicable for TEM analysis of any membrane protein that can be genetically tagged.

This protocol describes the cryoAPEX method, in which an APEX2-tagged membrane protein can be localized by transmission electron microscopy within optimally-preserved cell ultrastructure.

초구조적으로 보존된 세포 내 막 단백질 국소화의 전자 현미경 분석을 위한 CryoAPEX 방법

Key cellular events like signal transduction and membrane trafficking rely on proper protein location within cellular compartments. Understanding precise ...

Reconstruction of Single-Cell Innate Fluorescence Signatures by Confocal Microscopy

Described here is confocal reflection microscopy-assisted single-cell innate fluorescence analysis (CRIF), a minimally invasive method for reconstructing the innate cellular fluorescence signature from each individual live cell in a population distributed in a three-dimensional (3D) space. The innate fluorescence signature of a cell is a collection of fluorescence signals emitted by various biomolecules within the cell. Previous studies established that innate fluorescence signatures reflect various cellular properties and differences in physiological status and are a rich source of information for cell characterization and identification. Innate fluorescence signatures have been traditionally analyzed at the population level, necessitating a clonal culture, but not at the single-cell level. CRIF is particularly suitable for studies that require 3D resolution and/or selective extraction of fluorescence signals from individual cells. Because the fluorescence signature is an innate property of a cell, CRIF is also suitable for tag-free prediction of the type and/or physiological status of intact and single cells. This method may be a powerful tool for streamlined cell analysis, where the phenotype of each single cell in a heterogenous population can be directly assessed by its autofluorescence signature under a microscope without cell tagging.

Here, a protocol is presented for optically extracting and cataloging innate cellular fluorescence signatures (i.e., cellular autofluorescence) from every individual live cell distributed in a three-dimensional space. This method is suitable for studying the innate fluorescence signature of diverse biological systems at a single-cell resolution, including cells from bacteria, fungi, yeasts, plants, and animals.

공초점 현미경 검사법에 의한 단세포 인천성형광서명의 재구성

Described here is confocal reflection microscopy-assisted single-cell innate fluorescence analysis (CRIF), a minimally invasive method for reconstructing ...

Cryo-Electron Microscopic Grid Preparation for Time-Resolved Studies using a Novel Robotic System, Spotiton

The capture of short-lived molecular states triggered by the early encounter of two or more interacting particles continues to be an experimental challenge of great interest to the field of cryo-electron microscopy (cryo-EM). A few methodological strategies have been developed that support these &#34;time-resolved&#34; studies, one of which, Spotiton-a novel robotic system-combines the dispensing of picoliter-sized sample droplets with precise temporal and spatial control. The time-resolved Spotiton workflow offers a uniquely efficient approach to interrogate early structural rearrangements from minimal sample volume. Fired from independently controlled piezoelectric dispensers, two samples land and rapidly mix on a nanowire EM grid as it plunges toward the cryogen. Potentially hundreds of grids can be prepared in rapid succession from only a few microliters of a sample. Here, a detailed step-by-step protocol of the operation of the Spotiton system is presented with a focus on troubleshooting specific problems that arise during grid preparation.

The protocol presented here describes the use of Spotiton, a novel robotic system, to deliver two samples of interest onto a self-wicking, nanowire grid that mix for a minimum of 90 ms prior to vitrification in liquid cryogen.

새로운 로봇 시스템, 스포티폰을 사용하여 시간 해결 연구를 위한 극저온 전자 현미경 그리드 준비

The capture of short-lived molecular states triggered by the early encounter of two or more interacting particles continues to be an experimental ...

Direct Stochastic Optical Reconstruction Microscopy of Extracellular Vesicles in Three Dimensions

Extracellular vesicles (EVs) are released by all cell types and play an important role in cell signaling and homeostasis. The visualization of EVs often require indirect methods due to their small diameter (40-250 nm), which is beneath the diffraction limit of typical light microscopy. We have developed a super-resolution microscopy-based visualization of EVs to bypass the diffraction limit in both two and three dimensions. Using this approach, we can resolve the three-dimensional shape of EVs to within +/- 20 nm resolution on the XY-axis and +/- 50 nm resolution along the Z-axis. In conclusion, we propose that super-resolution microscopy be considered as a characterization method of EVs, including exosomes, as well as enveloped viruses.

Direct stochastic optical reconstruction microscopy (dSTORM) is used to bypass the typical diffraction limit of light microscopy and to view exosomes at the nanometer scale. It can be employed in both two and three dimensions to characterize exosomes.

3 차원에서 세포 외 소포의 직접 스토카스틱 광학 재건 현미경 검사

Extracellular vesicles (EVs) are released by all cell types and play an important role in cell signaling and homeostasis. The visualization of EVs often ...

Super-Resolution Microscopy of the Synaptonemal Complex Within the Caenorhabditis elegans Germline

During meiosis, homologous chromosomes must recognize and adhere to one another to allow for their correct segregation. One of the key events that secures the interaction of homologous chromosomes is the assembly of the synaptonemal complex (SC) in meiotic prophase I. Even though there is little sequence homology between protein components within the SC among different species, the general structure of the SC has been highly conserved during evolution. In electron micrographs, the SC appears as a tripartite, ladder-like structure composed of lateral elements or axes, transverse filaments, and a central element. 
However, precisely identifying the localization of individual components within the complex by electron microscopy to determine the molecular structure of the SC remains challenging. By contrast, fluorescence microscopy allows for the identification of individual protein components within the complex. However, since the SC is only ~100 nm wide, its substructure cannot be resolved by diffraction-limited conventional fluorescence microscopy. Thus, determining the molecular architecture of the SC requires super-resolution light microscopy techniques such as structured illumination microscopy (SIM), stimulated-emission depletion (STED) microscopy, or single-molecule localization microscopy (SMLM). 
To maintain the structure and interactions of individual components within the SC, it is important to observe the complex in an environment that is close to its native environment in the germ cells. Therefore, we demonstrate an immunohistochemistry and imaging protocol that enables the study of the substructure of the SC in intact, extruded Caenorhabditis elegans germline tissue with SMLM and STED microscopy. Directly fixing the tissue to the coverslip reduces the movement of the samples during imaging and minimizes aberrations in the sample to achieve the high resolution necessary to visualize the substructure of the SC in its biological context.

Super-Resolution Microscopy of the Synaptonemal Complex Within the Caenorhabditis elegans Germline

Super-resolution microscopy can provide a detailed insight into the organization of components within the synaptonemal complex in meiosis. Here, we demonstrate a protocol to resolve individual proteins of the Caenorhabditis elegans synaptonemal complex.

Caenorhabditis elegans 생식계열 내 시냅톤 복합체의 초고해상도 현미경

During meiosis, homologous chromosomes must recognize and adhere to one another to allow for their correct segregation. One of the key events that secures ...