この作品は、健康（R01 HL082792とR01 NS059348）とブリガムアンドウィメンズ病院循環器リーダーシップグループ賞の国立研究所によってサポートされていました。

<ol>
	<li>Friedl, P., Wolf, K., Lammerding, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nuclear+mechanics+during+cell+migration.">Nuclear mechanics during cell migration.</a> Curr Opin Cell Biol. 23, 55-64 (2011).</li><li>Mejat, A., Misteli, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=LINC+complexes+in+health+and+disease.">LINC complexes in health and disease.</a> Nucleus. 1, 40-52 (2010).</li><li>Worman, H. J., Fong, L. G., Muchir, A., Young, S. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laminopathies+and+the+long+strange+trip+from+basic+cell+biology+to+therapy.">Laminopathies and the long strange trip from basic cell biology to therapy.</a> J Clin Invest. 119, 1825-1836 (2009).</li><li>Caille, N., Tardy, Y., Meister, J. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessment+of+strain+field+in+endothelial+cells+subjected+to+uniaxial+deformation+of+their+substrate.">Assessment of strain field in endothelial cells subjected to uniaxial deformation of their substrate.</a> Ann Biomed Eng. 26, 409-416 (1998).</li><li>Lammerding, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lamins+A+and+C+but+not+lamin+B1+regulate+nuclear+mechanics.">Lamins A and C but not lamin B1 regulate nuclear mechanics.</a> J Biol Chem. 281, 25768-25780 (2006).</li><li>Lammerding, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Abnormal+nuclear+shape+and+impaired+mechanotransduction+in+emerin-deficient+cells.">Abnormal nuclear shape and impaired mechanotransduction in emerin-deficient cells.</a> J Cell Biol. 170, 781-791 (2005).</li><li>Lammerding, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lamin+A/C+deficiency+causes+defective+nuclear+mechanics+and+mechanotransduction.">Lamin A/C deficiency causes defective nuclear mechanics and mechanotransduction.</a> J Clin Invest. 113, 370-378 (2004).</li><li>Verstraeten, V. L., Ji, J. Y., Cummings, K. S., Lee, R. T., Lammerding, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Increased+mechanosensitivity+and+nuclear+stiffness+in+Hutchinson-Gilford+progeria+cells:+effects+of+farnesyltransferase+inhibitors.">Increased mechanosensitivity and nuclear stiffness in Hutchinson-Gilford progeria cells: effects of farnesyltransferase inhibitors.</a> Aging Cell. 7, 383-393 (2008).</li><li>Brooks, S. V., Zerba, E., Faulkner, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Injury+to+muscle+fibres+after+single+stretches+of+passive+and+maximally+stimulated+muscles+in+mice.">Injury to muscle fibres after single stretches of passive and maximally stimulated muscles in mice.</a> J Physiol. 488, 459-469 (1995).</li><li>Maniotis, A. J., Chen, C. S., Ingber, D. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Demonstration+of+mechanical+connections+between+integrins,+cytoskeletal+filaments,+and+nucleoplasm+that+stabilize+nuclear+structure.">Demonstration of mechanical connections between integrins, cytoskeletal filaments, and nucleoplasm that stabilize nuclear structure.</a> Proc Natl Acad Sci. 94, 849-854 (1997).</li></ol>

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基板のひずみ分析歪みのアプリケーションが正常に機械的応力を受けた細胞で誘導される核の変形を研究するために、核剛性に固有の核膜タンパク質の寄与を調査するために私達と他のグループによって使用されています。4-8この手法の利点は、プローブの機械的特性をすることです。彼らの正常な細胞と細胞骨格の環境で核を生きるのと、そのような契約筋肉や?...

<table border="1"><tbody><tr><td> 試薬の名前 </td><td> 会社 </td><td> カタログ番号 </td></tr><tr><td>フィブロネクチン</td><td>ミリポア</td><td> FC010 </td></tr><tr><td> MitoTrackerにより赤FMとグリーンFM </td><td>インビトロジェン</td><td> M22425およびM - 7514 </td></tr><tr><td>ヘキスト33342 </td><td>インビトロジェン</td><td> H3570 </td></tr><tr><td>ハンクのバッファ塩の生理食塩水</td><td>インビトロジェン</td><td> 14185 </td></tr><tr><td>フェノールフリー、DMEM </td><td>インビトロジェン</td><td> 21063 </td></tr><tr><td>ウシ胎仔血清</td><td> Alekenバイオ</td><td> FBSS500 </td></tr><tr><td>ペニシリン/ストレプトマイシン</td><td>シグマ</td><td> P0781 - 100ML </td></tr><tr><td>フィラメントとホウケイ酸ガラス</td><td>サッターインストゥルメント</td><td> BF100 - 78から10 </td></tr><tr><td> &quot;グロス/グロス非強化シリコンシートを、0.005 </td><td>専門製造株式会社</td><td></td></tr><tr><td>ダルベッコのリン酸緩衝生理食塩水</td><td>インビトロジェン</td><td> 14200 </td></tr><tr><td> 35ミリメートルのガラス底の培養皿（FluoroDish） </td><td>世界精密機器、INC </td><td> FD35 - 100 </td></tr><tr><td> Braycote 804真空グリース</td><td> SPI用品</td><td> 05133A - AB </td></tr></tbody></table>

biophysical assays to probe the mechanical properties of the interphase cell nucleus: substrate strain application and microneedle manipulation

ほとんどの真核細胞で、核は最大の細胞小器官であり、通常は周囲の細胞骨格の2〜10倍頑丈です。その結果、核の物理的性質は、生理学的および病理学的条件下で細胞全体の力学的挙動に大きく貢献する。例えば、好中球を移行し、がん細胞を侵入で、核の剛性は、組織内の狭いスペースを介して血管外漏出や通過時に大きな障害をもたらすことができる。1は、一方で、筋肉がするのに十分な構造的なサポートを必要とするような機械的にアクティブな組織中の細胞の核反復的な機械的ストレスに耐える。重要なのは、核がしっかりと細胞のアーキテクチャに統合され、それが物理的に偏光細胞、神経筋接合部シナプスの原子核で、例えば細胞内の運動と核の位置決めのための重要な要件、つまり、周囲の細胞骨格に接続されている、または細胞の移行の2当然のことながら、核の剛性とnucleo -細胞骨格結合を決定する上で重要な役割を果たすなどlaminsやnesprinsとして核膜タンパク質、、の変異を含む、ヒトの疾患の数に起因する最近示されているエメリー-ドレフュス型筋ジストロフィー、肢帯型筋ジストロフィー、および拡張型心筋症3多様な核膜タンパク質と特異的変異の影響の生物物理学的機能を調べるためには、我々は、単一の、生きた細胞で核の物理的性質を研究するための実験方法を開発しているグローバルまたはローカライズされた機械的な摂動を受ける。正確に適用される基板の歪みのアプリケーションへの応答で誘導される核の変形を測定することは、核の変形能に関する重要な情報を得られますし、別の変異や、特定の核膜タンパク質の欠損細胞株の間に定量的な比較を可能にします。マイクロニードルとローカライズされた細胞骨格の歪みアプリケーションは、このアッセイを補完するために使用され、核と細胞骨格との間の細胞内力伝達に関する追加情報を得ることができる。無傷の生細胞で核の力学を研究することは正常な細胞内のアーキテクチャを維持し、単離核での作業中に発生する可能性がある潜在的なアーティファクトを回避します。さらに、基板の歪みアプリケーションは、筋肉や他の組織の細胞（例えば、血管平滑筋細胞が血管緊張にさらされる）が経験する生理的ストレスのためのよいモデルを提示する。これらのツールは主に核の力学を研究するために開発されているが最後に、、彼らはまた、細胞骨格タンパク質とメカノシグナリングの機能を調査するために適用することができます。

Watch this Scientific Journal Video about Biophysical Assays to Probe the Mechanical Properties of the Interphase Cell Nucleus: Substrate Strain Application and Microneedle Manipulation at JoVE.com

Biophysical Assays to Probe the Mechanical Properties of the Interphase Cell Nucleus: Substrate Strain Application and Microneedle Manipulation

我々は、グローバルまたはローカライズされたひずみ申込みに応じて、単一の、生きている付着細胞で誘導核と細胞骨格の変形を測定するために二つの独立した、顕微鏡ベースのツールを紹介。これらの技術は、核の剛性を（すなわち、変形能）を決定すると、核と細胞骨格との間の細胞内力伝達を調べるために使用されます。

相間細胞核の力学特性を探査する生物物理学的なアッセイ：基板の歪みのアプリケーションおよびマイクロニードル操作

In most eukaryotic cells, the nucleus is the largest organelle and is typically 2 to 10 times stiffer than the surrounding cytoskeleton; consequently, the ...

biophysical-assays-to-probe-mechanical-properties-interphase-cell

Research

JoVE Journal

Biology

12.3K ビュー.  Department of Medicine, Cardiovascular Division. 我々は、グローバルまたはローカライズされたひずみ申込みに応じて、単一の、生きている付着細胞で誘導核と細胞骨格の変形を測定するために二つの独立した、顕微鏡ベースのツールを紹介。これらの技術は、核の剛性を（すなわち、変形能）を決定すると、核と細胞骨格との間の細胞内力伝達を調べるために使用されます。

ビデオ: Biophysical Assays to Probe the Mechanical Properties of the Interphase Cell Nucleus: Substrate Strain Application and Microneedle Manipulation

Mechanical Stimulation of Stem Cells Using Cyclic Uniaxial Strain

The role of mechanical forces in the development and maintenance of biological tissues is well documented, including several mechanically regulated phenomena such as bone remodeling, muscular hypertrophy, and smooth muscle cell plasticity. However, the forces involved are often extremely complex and difficult to monitor and control in vivo. To better investigate the effects of mechanical forces on cells, we have developed an in vitro method for applying uniaxial cyclic tensile strain to adherent cells cultured on elastic membranes. This method utilizes a custom-designed bioreactor with a motorized cam-rotor system to apply the desired force. Here we present a step-by-step video protocol demonstrating how to assemble the various components of each "stretch chamber", including, in this case, a silicone membrane with micropatterned topography to orient the cells with the direction of the strain. We also describe procedures for sterilizing the chambers, seeding cells onto the membrane, latching the chamber into the bioreactor, and adjusting the mechanical parameters (i.e. magnitude and rate of strain). The procedures outlined in this particular protocol are specific for seeding human mesenchymal stem cells onto silicone membranes with 10 &micro;m wide channels oriented parallel to the direction of strain. However, the methods and materials presented in this system are flexible enough to accommodate a number of variations on this theme: strain rate, magnitude, duration, cell type, membrane topography, membrane coating, etc. can all be tailored to the desired application or outcome. This is a robust method for investigating the effects of uniaxial tensile strain applied to cells in vitro.

It is widely understood that mechanical forces in the body can influence cell differentiation and proliferation. Here we present a video protocol demonstrating the use of a custom-built bioreactor for delivering uniaxial cyclic tensile strain to stem cells cultured on flexible micropatterned substrates.

繰返し一軸性歪みを用いた幹細胞の機械的刺激

The role of mechanical forces in the development and maintenance of biological tissues is well documented, including several mechanically regulated ...

生物学

Photobleaching Assays (FRAP &amp; FLIP) to Measure Chromatin Protein Dynamics in Living Embryonic Stem Cells

Fluorescence Recovery After Photobleaching (FRAP) and Fluorescence Loss In Photobleaching (FLIP) enable the study of protein dynamics in living cells with good spatial and temporal resolution. Here we describe how to perform FRAP and FLIP assays of chromatin proteins, including H1 and HP1, in mouse embryonic stem (ES) cells. In a FRAP experiment, cells are transfected, either transiently or stably, with a protein of interest fused with the green fluorescent protein (GFP) or derivatives thereof (YFP, CFP, Cherry, etc.). In the transfected, fluorescing cells, an intense focused laser beam bleaches a relatively small region of interest (ROI). The laser wavelength is selected according to the fluorescent protein used for fusion. The laser light irreversibly bleaches the fluorescent signal of molecules in the ROI and, immediately following bleaching, the recovery of the fluorescent signal in the bleached area - mediated by the replacement of the bleached molecules with the unbleached molecules - is monitored using time lapse imaging. The generated fluorescence recovery curves provide information on the protein's mobility. If the fluorescent molecules are immobile, no fluorescence recovery will be observed. In a complementary approach, Fluorescence Loss in Photobleaching (FLIP), the laser beam bleaches the same spot repeatedly and the signal intensity is measured elsewhere in the fluorescing cell. FLIP experiments therefore measure signal decay rather than fluorescence recovery and are useful to determine protein mobility as well as protein shuttling between cellular compartments. Transient binding is a common property of chromatin-associated proteins. Although the major fraction of each chromatin protein is bound to chromatin at any given moment at steady state, the binding is transient and most chromatin proteins have a high turnover on chromatin, with a residence time in the order of seconds. These properties are crucial for generating high plasticity in genome expression1. Photobleaching experiments are therefore particularly useful to determine chromatin plasticity using GFP-fusion versions of chromatin structural proteins, especially in ES cells, where the dynamic exchange of chromatin proteins (including heterochromatin protein 1 (HP1), linker histone H1 and core histones) is higher than in differentiated cells2,3.

Photobleaching Assays FRAP &amp; FLIP to Measure Chromatin Protein Dynamics in Living Embryonic Stem Cells

We describe photobleaching methods including Fluorescence Recovery After Photobleaching (FRAP) and Fluorescence Loss In Photobleaching (FLIP) to monitor chromatin protein dynamics in embryonic stem (ES) cells. Chromatin protein dynamics, which is considered to be one of the means to study chromatin plasticity, is enhanced in pluripotent cells.

胚性幹細胞を生体内でクロマチン蛋白質のダイナミクスを測定するアッセイ（FRAP＆FLIP）を光退色

Fluorescence Recovery After Photobleaching (FRAP) and Fluorescence Loss In Photobleaching (FLIP) enable the study of protein dynamics in living cells with ...

Pharmacological and Functional Genetic Assays to Manipulate Regeneration of the Planarian Dugesia japonica

Free-living planarian flatworms have a long history of experimental usage owing to their remarkable regenerative abilities1. Small fragments excised from these animals reform the original body plan following regeneration of missing body structures. For example if a 'trunk' fragment is cut from an intact worm, a new 'head' will regenerate anteriorly and a 'tail' will regenerate posteriorly restoring the original 'head-to-tail' polarity of body structures prior to amputation (Figure 1A).
Regeneration is driven by planarian stem cells, known as 'neoblasts' which differentiate into ~30 different cell types during normal body homeostasis and enforced tissue regeneration. This regenerative process is robust and easy to demonstrate. Owing to the dedication of several pioneering labs, many tools and functional genetic methods have now been optimized for this model system. Consequently, considerable recent progress has been made in understanding and manipulating the molecular events underpinning planarian developmental plasticity2-9.
The planarian model system will be of interest to a broad range of scientists. For neuroscientists, the model affords the opportunity to study the regeneration of an entire nervous system, rather than simply the regrowth/repair of single nerve cell process that typically are the focus of study in many established models. Planarians express a plethora of neurotransmitters10, represent an important system for studying evolution of the central nervous system11, 12 and have behavioral screening potential13, 14. 
Regenerative outcomes are amenable to manipulation by pharmacological and genetic apparoaches. For example, drugs can be screened for effects on regeneration simply by placing body fragments in drug-containing solutions at different time points after amputation. The role of individual genes can be studied using knockdown methods (in vivo RNAi), which can be achieved either through cycles of microinjection or by feeding bacterially-expressed dsRNA constructs8, 9, 15. Both approaches can produce visually striking phenotypes at high penetrance- for example, regeneration of bipolar animals16-21. To facilitate adoption of this model and implementation of such methods, we showcase in this video article protocols for pharmacological and genetic assays (in vivo RNAi by feeding) using the planarian Dugesia japonica.

Pharmacological and Functional Genetic Assays to Manipulate Regeneration of the Planarian Dugesia japonica

An attractive model for studying stem cell differentiation within a live animal is the planarian flatworm. Regeneration is studied by simple amputation experiments that are easily performed in a basic laboratory and are amenable to pharmacological and genetic (in vivo RNAi) manipulation as detailed by protocols in this article.

プラナリアの再生を操作するために薬理学的および機能的遺伝学的アッセイ<emジャポニカ> Dugesia</em

Free-living planarian flatworms have a long history of experimental usage owing to their remarkable regenerative abilities1. Small fragments excised from ...

Selective Capture of 5-hydroxymethylcytosine from Genomic DNA

5-methylcytosine (5-mC) constitutes ~2-8% of the total cytosines in human genomic DNA and impacts a broad range of biological functions, including gene expression, maintenance of genome integrity, parental imprinting, X-chromosome inactivation, regulation of development, aging, and cancer1. Recently, the presence of an oxidized 5-mC, 5-hydroxymethylcytosine (5-hmC), was discovered in mammalian cells, in particular in embryonic stem (ES) cells and neuronal cells2-4. 5-hmC is generated by oxidation of 5-mC catalyzed by TET family iron (II)/&alpha;-ketoglutarate-dependent dioxygenases2, 3. 5-hmC is proposed to be involved in the maintenance of embryonic stem (mES) cell, normal hematopoiesis and malignancies, and zygote development2, 5-10. To better understand the function of 5-hmC, a reliable and straightforward sequencing system is essential. Traditional bisulfite sequencing cannot distinguish 5-hmC from 5-mC11. To unravel the biology of 5-hmC, we have developed a highly efficient and selective chemical approach to label and capture 5-hmC, taking advantage of a bacteriophage enzyme that adds a glucose moiety to 5-hmC specifically12.
Here we describe a straightforward two-step procedure for selective chemical labeling of 5-hmC. In the first labeling step, 5-hmC in genomic DNA is labeled with a 6-azide-glucose catalyzed by &beta;-GT, a glucosyltransferase from T4 bacteriophage, in a way that transfers the 6-azide-glucose to 5-hmC from the modified cofactor, UDP-6-N3-Glc (6-N3UDPG). In the second step, biotinylation, a disulfide biotin linker is attached to the azide group by click chemistry. Both steps are highly specific and efficient, leading to complete labeling regardless of the abundance of 5-hmC in genomic regions and giving extremely low background. Following biotinylation of 5-hmC, the 5-hmC-containing DNA fragments are then selectively captured using streptavidin beads in a density-independent manner. The resulting 5-hmC-enriched DNA fragments could be used for downstream analyses, including next-generation sequencing.
Our selective labeling and capture protocol confers high sensitivity, applicable to any source of genomic DNA with variable/diverse 5-hmC abundances. Although the main purpose of this protocol is its downstream application (i.e., next-generation sequencing to map out the 5-hmC distribution in genome), it is compatible with single-molecule, real-time SMRT (DNA) sequencing, which is capable of delivering single-base resolution sequencing of 5-hmC.

Described is a two-step labeling process using &beta;-glucosyltransferase (&beta;-GT) to transfer an azide-glucose to 5-hmC, followed by click chemistry to transfer a biotin linker for easy and density-independent enrichment. This efficient and specific labeling method enables enrichment of 5-hmC with extremely low background and high-throughput epigenomic mapping via next-generation sequencing.

ゲノムDNAから5  - ヒドロキシの選択的捕獲

5-methylcytosine (5-mC) constitutes ~2-8% of the total cytosines in human genomic DNA and impacts a broad range of biological functions, including gene ...

Super-resolution Imaging of the Bacterial Division Machinery

Bacterial cell division requires the coordinated assembly of more than ten essential proteins at midcell1,2. Central to this process is the formation of a ring-like suprastructure (Z-ring) by the FtsZ protein at the division plan3,4. The Z-ring consists of multiple single-stranded FtsZ protofilaments, and understanding the arrangement of the protofilaments inside the Z-ring will provide insight into the mechanism of Z-ring assembly and its function as a force generator5,6. This information has remained elusive due to current limitations in conventional fluorescence microscopy and electron microscopy. Conventional fluorescence microscopy is unable to provide a high-resolution image of the Z-ring due to the diffraction limit of light (~200 nm). Electron cryotomographic imaging has detected scattered FtsZ protofilaments in small C. crescentus cells7, but is difficult to apply to larger cells such as E. coli or B. subtilis. Here we describe the application of a super-resolution fluorescence microscopy method, Photoactivated Localization Microscopy (PALM), to quantitatively characterize the structural organization of the E. coli Z-ring8.
	PALM imaging offers both high spatial resolution (~35 nm) and specific labeling to enable unambiguous identification of target proteins. We labeled FtsZ with the photoactivatable fluorescent protein mEos2, which switches from green fluorescence (excitation = 488 nm) to red fluorescence (excitation = 561 nm) upon activation at 405 nm9. During a PALM experiment, single FtsZ-mEos2 molecules are stochastically activated and the corresponding centroid positions of the single molecules are determined with &lt;20 nm precision. A super-resolution image of the Z-ring is then reconstructed by superimposing the centroid positions of all detected FtsZ-mEos2 molecules.
	Using this method, we found that the Z-ring has a fixed width of ~100 nm and is composed of a loose bundle of FtsZ protofilaments that overlap with each other in three dimensions. These data provide a springboard for further investigations of the cell cycle dependent changes of the Z-ring10 and can be applied to other proteins of interest.

We describe a super-resolution imaging method to probe the structural organization of the bacterial FtsZ-ring, an essential apparatus for cell division. This method is based on quantitative analyses of photoactivated localization microscopy (PALM) images and can be applied to other bacterial cytoskeletal proteins.

細菌分裂機械の超解像イメージング

Bacterial cell division requires the coordinated  assembly of more than ten essential proteins at midcell1,2. Central  to this process is the formation of ...

Application of an In vitro DNA Protection Assay to Visualize Stress Mediation Properties of the Dps Protein

Oxidative stress is an unavoidable byproduct of aerobic life. Molecular oxygen is essential for terrestrial metabolism, but it also takes part in many damaging reactions within living organisms. The combination of aerobic metabolism and iron, which is another vital compound for life, is enough to produce radicals through Fenton chemistry and degrade cellular components. DNA degradation is arguably the most damaging process involving intracellular radicals, as DNA repair is far from trivial. The assay presented in this article offers a quantitative technique to measure and visualize the effect of molecules and enzymes on radical-mediated DNA damage.
The DNA protection assay is a simple, quick, and robust tool for the in vitro characterization of the protective properties of proteins or chemicals. It involves exposing DNA to a damaging oxidative reaction and adding varying concentrations of the compound of interest. The reduction or increase of DNA damage as a function of compound concentration is then visualized using gel electrophoresis. In this article we demonstrate the technique of the DNA protection assay by measuring the protective properties of the DNA-binding protein from starved cells (Dps). Dps is a mini-ferritin that is utilized by more than 300 bacterial species to powerfully combat environmental stressors. Here we present the Dps purification protocol and the optimized assay conditions for evaluating DNA protection by Dps.

Application of an In vitro DNA Protection Assay to Visualize Stress Mediation Properties of the Dps Protein

The DNA-binding protein from starved cells (Dps) plays a crucial role in combating bacterial stress. This article discusses the purification of E. coli Dps and the protocol for an in vitro assay demonstrating Dps-mediated protection of DNA from degradation by reactive oxygen species.

の適用<em&gt;インビトロ</emDPSタンパク質のストレス調停プロパティを可視化するために&gt; DNA保護アッセイ

Oxidative stress is an unavoidable byproduct of  aerobic life.  Molecular oxygen is  essential for terrestrial metabolism, but it also takes part in many ...

The Cell-based L-Glutathione Protection Assays to Study Endocytosis and Recycling of Plasma Membrane Proteins

Membrane trafficking involves transport of proteins from the plasma membrane to the cell interior (i.e. endocytosis) followed by trafficking to lysosomes for degradation or to the plasma membrane for recycling. The cell based L-glutathione protection assays can be used to study endocytosis and recycling of protein receptors, channels, transporters, and adhesion molecules localized at the cell surface. The endocytic assay requires labeling of cell surface proteins with a cell membrane impermeable biotin containing a disulfide bond and the N-hydroxysuccinimide (NHS) ester at 4 &#186;C -&#160;a temperature at which membrane trafficking does not occur. Endocytosis of biotinylated plasma membrane proteins is induced by incubation at 37 &#186;C. Next, the temperature is decreased again to 4 &#186;C to stop endocytic trafficking and the disulfide bond in biotin covalently attached to proteins that have remained at the plasma membrane is reduced with L-glutathione. At this point, only proteins that were endocytosed remain protected from L-glutathione and thus remain biotinylated. After cell lysis, biotinylated proteins are isolated with streptavidin agarose, eluted from agarose, and the biotinylated protein of interest is detected by western blotting. During the recycling assay, after biotinylation cells are incubated at 37 &#176;C to load endocytic vesicles with biotinylated proteins and the disulfide bond in biotin covalently attached to proteins remaining at the plasma membrane is reduced with L-glutathione at 4 &#186;C as in the endocytic assay. Next, cells are incubated again at 37 &#176;C to allow biotinylated proteins from endocytic vesicles to recycle to the plasma membrane. Cells are then incubated at 4 &#186;C, and the disulfide bond in biotin attached to proteins that recycled to the plasma membranes is reduced with L-glutathione. The biotinylated proteins protected from L-glutathione are those that did not recycle to the plasma membrane.

Membrane trafficking involves transport of proteins from the plasma membrane to the cell interior (i.e. endocytosis) followed by trafficking to lysosomes for degradation or to the plasma membrane for recycling. Methods described in this article are designed to study endocytosis and recycling of plasma membrane proteins.

セルベースの​​L-グルタチオン保護アッセイ細胞膜タンパク質のエンドサイトーシスとリサイクルを研究するために、

Membrane trafficking involves transport of proteins from the plasma membrane to the cell interior (i.e. endocytosis) followed by trafficking to lysosomes ...

Probe-based Real-time PCR Approaches for Quantitative Measurement of microRNAs

Probe-based quantitative PCR (qPCR) is a favoured method for measuring transcript abundance, since it is one of the most sensitive detection methods that provides an accurate and reproducible analysis. Probe-based chemistry offers the least background fluorescence as compared to other (dye-based) chemistries. Presently, there are several platforms available that use probe-based chemistry to quantitate transcript abundance. qPCR in a 96 well plate is the most routinely used method, however only a maximum of 96 samples or miRNAs can be tested in a single run. This is time-consuming and tedious if a large number of samples/miRNAs are to be analyzed. High-throughput probe-based platforms such as microfluidics (e.g. TaqMan Array Card) and nanofluidics arrays (e.g. OpenArray) offer ease to reproducibly and efficiently detect the abundance of multiple microRNAs in a large number of samples in a short time. Here, we demonstrate the experimental setup and protocol for miRNA quantitation from serum or plasma-EDTA samples, using probe-based chemistry and three different platforms (96 well plate, microfluidics and nanofluidics arrays) offering increasing levels of throughput.

Circulating microRNAs have recently emerged as promising and novel biomarkers for various cancers and other diseases. The goal of this article is to discuss three different probe-based real-time PCR platforms and methods that are available to quantify and determine the abundance of circulating microRNAs.

プローブベースのリアルタイムPCRは、マイクロRNAの定量的測定のためのアプローチ

Probe-based quantitative PCR (qPCR) is a favoured method for measuring transcript abundance, since it is one of the most sensitive detection methods that ...

Sequential Application of Glass Coverslips to Assess the Compressive Stiffness of the Mouse Lens: Strain and Morphometric Analyses

The eye lens is a transparent organ that refracts and focuses light to form a clear image on the retina. In humans, ciliary muscles contract to deform the lens, leading to an increase in the lens&#39; optical power to focus on nearby objects, a process known as accommodation. Age-related changes in lens stiffness have been linked to presbyopia, a reduction in the lens&#39; ability to accommodate, and, by extension, the need for reading glasses. Even though mouse lenses do not accommodate or develop presbyopia, mouse models can provide an invaluable genetic tool for understanding lens pathologies, and the accelerated aging observed in mice enables the study of age-related changes in the lens. This protocol demonstrates a simple, precise, and cost-effective method for determining mouse lens stiffness, using glass coverslips to apply sequentially increasing compressive loads onto the lens. Representative data confirm that mouse lenses become stiffer with age, like human lenses. This method is highly reproducible and can potentially be scaled up to mechanically test lenses from larger animals.

Age-related increases in eye lens stiffness are linked to presbyopia. This protocol describes a simple, cost-effective method for measuring mouse lens stiffness. Mouse lenses, like human lenses, become stiffer with age. This method is precise and can be adapted for lenses from larger animals.

マウスレンズの圧縮剛性を評価するために、ガラスカバースリップの逐次適用：ひずみと形態計測分析

The eye lens is a transparent organ that refracts and focuses light to form a clear image on the retina. In humans, ciliary muscles contract to deform the ...

Expression of Fluorescent Fusion Proteins in Murine Bone Marrow-derived Dendritic Cells and Macrophages

Dendritic cells and macrophages are crucial cells that form the first line of defense against pathogens. They also play important roles in the initiation of an adaptive immune response. Experimental work with these cells is rather challenging. Their abundance in organs and tissues is relatively low. As a result, they cannot be isolated in large numbers. They are also difficult to transfect with cDNA constructs. In the murine model, these problems can be partially overcome by in vitro differentiation from bone marrow progenitors in the presence of M-CSF for macrophages or GM-CSF for dendritic cells. In this way, it is possible to obtain large amounts of these cells from very few animals. Moreover, bone marrow progenitors can be transduced with retroviral vectors carrying cDNA constructs during early stages of cultivation prior to their differentiation into bone marrow derived dendritic cells and macrophages. Thus, retroviral transduction followed by differentiation in vitro can be used to express various cDNA constructs in these cells. The ability to express ectopic proteins substantially extends the range of experiments that can be performed on these cells, including live cell imaging of fluorescent proteins, tandem purifications for interactome analyses, structure-function analyses, monitoring of cellular functions with biosensors and many others. In this article, we describe a detailed protocol for retroviral transduction of murine bone marrow derived dendritic cells and macrophages with vectors coding for fluorescently-tagged proteins. On the example of two adaptor proteins, OPAL1 and PSTPIP2, we demonstrate its practical application in flow cytometry and microscopy. We also discuss the advantages and limitations of this approach.

In this article, we provide a detailed protocol for the expression of fluorescent fusion proteins in murine bone marrow derived dendritic cells and macrophages. The method is based on the transduction of bone marrow progenitors with retroviral constructs followed by differentiation into macrophages and dendritic cells in vitro.

マウス骨髄由来の樹状細胞とマクロファージの蛍光融合タンパク質の発現

Dendritic cells and macrophages are crucial cells that form the first line of defense against pathogens. They also play important roles in the initiation ...