1. Preparação da Amostra O primeiro passo para Western blotting é a preparação da amostra. Para preparar as amostras para a execução de um gel de células e tecidos precisam ser lisadas para liberar as proteínas de interesse. <ul><li> Um conveniente, reagente pronto para uso que é versátil e fácil de usar para extração de proteínas solúveis é CytoBuster ou PhosphoSafe. Estes buffers extração contêm detergentes otimizado para extração eficiente de proteínas solúveis a partir de células de mamíferos e insetos. A suave, a composição não-iônico de CytoBuster Reagente de Extracção de proteínas permite o isolamento de ativos endógenos ou funcionalmente proteínas expressas sem necessidade de tratamento secundário, como sonicação ou congelamento / descongelamento. PhoshoSafe tem a vantagem de conter quatro inibidores da fosfatase. <ol><li> Agregar as células por centrifugação a baixa velocidade (por exemplo, 5 min a 2500 xg), escorra o pellet celular também. </li><li> Ressuspender as células em CytoBuster Reagente de Extracção de proteínas usando 150 mL por 10 6 células (quantidade ideal de CytoBuster Reagente de Extracção de proteínas pode variar de acordo com o tamanho da célula). </li><li> Incubar a temperatura ambiente por 5 min. </li><li> Transferência para um tubo adequado e girar por 5 min a 16.000 xg, a 4 ° C. </li><li> Transferência apuradas sobrenadante (extrato celular) para um novo tubo e prosseguir com a análise. </li></ol></li><li> Para a extração de proteínas especializadas, recomendamos o uso de nossos alta qualidade Kits ProteoExtract. EMD tem mais de uma dúzia de kits para o isolamento mitocondrial, a extração de proteoma subcelular, a extração de proteínas transmembrana, e muitos outros. Visite nossa página de destino Western blot para mais detalhes. </li><li> EMD também vende uma ampla variedade de protease e define fosfatase cocktail inibidor. Assim como ocorre lise, desfosforilação proteólise, e desnaturação começar. Estes eventos podem ser abrandado tremendamente se as amostras são mantidas em gelo ou a 4 ° C em todos os momentos e os inibidores apropriadas são adicionadas novas para o tampão de lise. Visite nossa página de destino Western blot para mais detalhes. </li></ul> 2. SDS-PAGE O segundo passo é a separação Western blotting proteína. As proteínas são separadas com base no peso molecular. <ul><li> Você pode fazer seu próprio gel PAGE, no entanto vamos estar usando um gel comercialmente pré-moldados. <ol><li> Depois de preparar a sua amostra, você está pronto para determinar a concentração de proteína. EMD tem dois kits para este para medir a concentração, sendo um deles a não-interferência Kit Ensaio de proteína e sendo o outro a BCA Protein Assay Kit. </li><li> Uma vez que a concentração de proteína é avaliado estamos prontos para preparar a nossa amostra para o carregamento do gel. Anticorpos normalmente reconhecer uma pequena porção da proteína de interesse (referido como o epítopo) e neste domínio podem residir dentro da conformação 3D da proteína. Para permitir o acesso do anticorpo para esta parcela é necessário desdobrar a proteína. </li><li> Para desnaturar, use um tampão de carregamento com a desnaturação sulfato de detergente aniônico dodecil sódio (SDS), e ferva a mistura em 95-100 ° C por 5 minutos. Um tampão de carregamento fácil e conveniente de usar é tampão de amostra 4X. </li></ol></li><li> Carregar a primeira pista do poço com marcador Trail Mix Protein. Este marcador tem três bandas de referência que permitem monitorar eletroforese. Quando o gel estiver manchado, bandas são visíveis desde 10 10-225 kDa. </li><li> Preencha a unidade de eletroforese com tampão de corrida. Para géis PAGE, esta é geralmente 1X Tris-glicina. Para receitas de buffer mais detalhadas, visite a página de Western blotting. A Merck oferece reagentes de alta qualidade buffers com nossa linha química OmniPur. Executar o gel a 220V por 1 hora. </li><li> Uma vez que as proteínas se separaram, mancha o gel com Coomassie blue para garantir as proteínas migraram de forma uniforme e uniformemente. RAPIDstain é uma mancha ultra-sensível, que está pronto para uso. Descoloração não é necessária. </li></ul> 3. Transferência de proteína Assim como proteínas com uma carga elétrica pode ser induzida a viajar por um gel em um campo elétrico, pode assim as proteínas ser transferidos em um campo elétrico a partir do gel para uma membrana, sendo ou PVDF ou de nitrocelulose. <ul><li> Hoje vamos fazer uma transferência molhado. Na transferência de molhado, o gel ea membrana são prensadas entre esponja e papel (esponja / papel / gel / membrana / papel / esponja) e todos são apertadas em conjunto, após garantir a ausência de bolhas de ar formada entre o gel ea membrana. O sanduíche está submerso em tampão de transferência para que um campo elétrico é aplicado. As proteínas de carga negativa viajar para o eletrodo com carga positiva, mas a membrana deixa-los, os une e as impede de prosseguir. </li><li> Dois tipos de membranas são disponíveis: nitrocelulose e PVDF. Ambos funcionam bem. Hoje vamos estar usando PVDF. Membranas PVDF requerem imersão em methanol por alguns minutos, seguido de gelo do buffer de transferência fria por 5 minutos. O gel também precisa equilibrar por alguns minutos no gelo frio do buffer de transferência. Não fazer isso pode diminuir o gel durante a transferência. </li><li> O buffer de transferência molhado é 1X Tris-glicina com metanol 20%. Preparações tampão detalhadas estão disponíveis em nosso website. </li><li> Uma vez que a transferência estiver completa, é uma boa idéia para visualizar proteínas para assegurar uma transferência sem bolsas de ar. Isto pode ser feito facilmente com Blot RedAlert ocidental Stain. Esta mancha é ready-to-use e descoloração pode ser feito facilmente com água. </li></ul> 4. Anticorpos e reagentes de Acessórios <ul><li> O primeiro passo para fazer a sondagem e do anticorpo ao antígeno é bloquear a membrana. Bloqueio da membrana impede ligação não específica de fundo. </li><li> Tanto de leite sem gordura ou BSA pode ser usado como uma solução de bloqueio. Entretanto, ao usar fosfo-anticorpos específicos, não é recomendado o uso de leite, uma vez que fará com elevado ruído de fundo. </li><li> EMD oferece diversos reagentes de alta qualidade de bloqueio, incluindo SeaBlock, que é um agente não-mamíferos bloqueio e QuickBlocker BLOT, que é preparado, ready-to-use agente bloqueador. Temos também de alta qualidade BSA (Fração V) disponíveis. <ol><li> Incubar a membrana uma hora à temperatura ambiente sob agitação suave. </li><li> Lavar três vezes em PBST TBST ou após a incubação. Uma maneira fácil e conveniente de fazer TBST ou PBST é usar o nosso comprimidos (comprimidos PBS TWEEN / Comprimidos TWEEN TBS) </li></ol></li><li> Uma vez que a membrana foi bloqueado, você está pronto para incubar com o anticorpo primário. EMD tem vindo a oferecer um portfólio completo de anticorpos excepcional, com a melhor garantia de anticorpos na indústria há mais de 30 anos. Lembre-se que, com todos os anticorpos EMD, oferecemos uma completa garantia 100% sem risco. Compra um anticorpo e usá-lo para qualquer especificidade de espécie ou aplicação que você deseja. Se o anticorpo não trabalhar para sua satisfação, nós forneceremos um crédito total para ser usado em qualquer outro produto. Para mais detalhes, visite a nossa página web Western blotting. <ol><li> Hoje vamos estar a incubar o nosso anticorpo primário usando uma solução de 1 de SignalBoost. SignalBoost é um grande produto permitindo que o seu sinal a ser melhorado significativamente. Simplesmente incubar o seu anticorpo primário em uma solução e incubar por 1 hora ou como faria normalmente. Não há necessidade de adicionar mais agentes bloqueadores. Alternativamente, você pode usar BSA ou leite em pó desnatado como um agente de bloqueio. </li><li> Lavar com TBST. Fazemos TBST usando o pronto-a dissolver comprimido TBST. </li><li> Incubar o seu anticorpo secundário usando uma solução de 2 de SignalBoost. Incubar o anticorpo secundário em tampão de bloqueio por 1 hora. Lavar a membrana de novo várias vezes com TBST. </li></ol></li></ul> 5. Detecção Para HRP conjugando anticorpos secundários, ECL é tradicionalmente utilizada. Um reagente ECL excelente que oferecemos é RapidStep. As vantagens de RapidStep são de que haja mistura de luminal ou enhancer é necessária. Basta pulverizar a membrana algumas vezes e desenvolver usando x-ray filme. RapidStep oferece uma sensibilidade pictograma baixo, bem como emitir luz por até 2 horas após a adição de substrato.

<ol>
	<li>Towbin, H., Staehelin, T., Gordon, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrophoretic+transfer+of+proteins+from+polyacrylamide+gels+to+nitrocellulose+sheets:+procedure+and+some+applications.">Electrophoretic transfer of proteins from polyacrylamide gels to nitrocellulose sheets: procedure and some applications.</a> Proc Natl Acad Sci U S A. 76 (9), 4350-4354 (1979).</li><li>Renart, J., Reiser, J., Stark, G. R., R, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transfer+of+proteins+from+gels+to+diazobenzyloxymethyl-paper+and+detection+with+antisera:+a+method+for+studying+antibody+specificity+and+antigen+structure.">Transfer of proteins from gels to diazobenzyloxymethyl-paper and detection with antisera: a method for studying antibody specificity and antigen structure.</a> Proc Natl Acad Sci U S A. 76 (7), 3116-3120 (1979).</li><li>Burnette, W. N. '. W. e. s. t. e. r. n. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=blotting':+electrophoretic+transfer+of+proteins+from+sodium+dodecyl+sulfate+polyacrylamide+gels+to+unmodified+nitrocellulose+and+radiographic+detection+with+antibody+and+radioiodinated+protein+A.">blotting': electrophoretic transfer of proteins from sodium dodecyl sulfate polyacrylamide gels to unmodified nitrocellulose and radiographic detection with antibody and radioiodinated protein A.</a> Analytical Biochemistry. 112, 195-203 (1981).</li><li>Ambroz, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improving+quantification+accuracy+for+Western+blots+Image+Analysis.">Improving quantification accuracy for Western blots Image Analysis.</a> , (2006).</li><li>Quan, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reactive+oxygen+species-mediated+endoplasmic+reticulum+stress+and+mitochondrial+dysfunction+contribute+to+cirsimartitin-induced+apoptosis+in+human+gallbladder+carcinoma+GBC-SD+cells.">Reactive oxygen species-mediated endoplasmic reticulum stress and mitochondrial dysfunction contribute to cirsimartitin-induced apoptosis in human gallbladder carcinoma GBC-SD cells.</a> Cancer Lett Article. , (2010).</li><li>O'Malley, D. e. r. v. i. a. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Alterations+in+colonic+corticotrophin-releasing+factor+receptors+in+the+maternally+separated+rat+model+of+irritable+bowel+syndrome:+Differential+effects+of+acute+psychological+and+physical+stressors.">Alterations in colonic corticotrophin-releasing factor receptors in the maternally separated rat model of irritable bowel syndrome: Differential effects of acute psychological and physical stressors.</a> Peptides. 31 (4), 662-670 (2010).</li></ol>

Os autores Anna Eslami e Jesse Lujan são empregados por EMD Chemicals Inc, que produz reagentes e instrumentos utilizados no presente artigo.

Nesta apresentação de vídeo, destacamos os principais passos na Western blotting, que são a preparação da amostra, SDS-PAGE, membrana bloqueio / sondagem com anticorpos e detecção. Para cada etapa do processo, os protocolos apropriados e reagentes apropriados devem ser utilizados para atingir resultados de alta qualidade.

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">	
		
		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>CytoBuster&trade; Protein Extraction Reagent</td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>71009</td>
<td><a href="http://www.emdbiosciences.com/cytobuster">www.emdbiosciences.com/cytobuster</a> <a href="http://www.merck4biosciences.com/cytobuster">www.merck4biosciences.com/cytobuster</a></td>
</tr>
<tr>
<td>PhosphoSafe&trade; Extraction Reagent</td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>71296</td>
<td><a href="http://www.emdbiosciences.com/phosphosafe">www.emdbiosciences.com/phosphosafe</a> <a href="http://www.merck4biosciences.com/phosphosafe">www.merck4biosciences.com/phosphosafe</a></td>
</tr>
<tr>
<td>Non-Interfering Protein Assay&trade; Kit</td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>488250</td>
<td><a href="http://www.emdbiosciences.com/noninterfering">www.emdbiosciences.com/noninterfering</a> <a href="http://www.merck4biosciences.com/noninterfering">www.merck4biosciences.com/noninterfering</a></td>
</tr>
<tr>
<td>BCA Protein Assay Kit </td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>71285</td>
<td><a href="http://www.emdbiosciences.com/BCA">www.emdbiosciences.com/BCA</a> <a href="http://www.merck4biosciences.com/BCA">www.merck4biosciences.com/BCA</a></td>
</tr>
<tr>
<td>4X SDS Sample Buffer </td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>70607</td>
<td><a href="http://www.emdbiosciences.com/4XSDS">www.emdbiosciences.com/4XSDS</a> <a href="http://www.merck4biosciences.com/4XSDS">www.merck4biosciences.com/4XSDS</a></td>
</tr>
<tr>
<td>Trail Mix&trade; Protein Markers</td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>70980</td>
<td><a href="http://www.emdbiosciences.com/trailmix">www.emdbiosciences.com/trailmix</a> <a href="http://www.merck4biosciences.com/trailmix">www.merck4biosciences.com/trailmix</a></td>
</tr>
<tr>
<td>ProteoExtract&trade; Protein Extraction Kits</td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>&nbsp;</td>
<td><a href="http://www.emdbiosciences.com/proteoextract">www.emdbiosciences.com/proteoextract</a> <a href="http://www.merck4biosciences.com/proteoextract">www.merck4biosciences.com/proteoextract</a></td>
</tr>
<tr>
<td>OmniPur&reg; Products</td>
<td>&nbsp;</td>
<td>EMD Chemicals</td>
<td>&nbsp;</td>
<td><a href="http://www.emdbiosciences.com/omnipur">www.emdbiosciences.com/omnipur</a></td>
</tr>
<tr>
<td>RAPIDstain&trade; Reagent</td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>553215</td>
<td><a href="http://www.emdbiosciences.com/rapidstain">www.emdbiosciences.com/rapidstain</a> <a href="http://www.merck4biosciences.com/rapidstain">www.merck4biosciences.com/rapidstain</a></td>
</tr>
<tr>
<td>RedAlert&trade; 10X Western Blot Stain</td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>71078</td>
<td><a href="http://www.emdbiosciences.com/redalert">www.emdbiosciences.com/redalert</a> <a href="http://www.merck4biosciences.com/redalert">www.merck4biosciences.com/redalert</a></td>
</tr>
<tr>
<td>SeaBlock&trade; Reagent, Salmon Plasma</td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>558300</td>
<td><a href="http://www.emdbiosciences.com/seablock">www.emdbiosciences.com/seablock</a> <a href="http://www.merck4biosciences.com/seablock">www.merck4biosciences.com/seablock</a></td>
</tr>
<tr>
<td>BLOT-QuickBlocker Reagent</td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>WB57</td>
<td><a href="http://www.emdbiosciences.com/quickblocker">www.emdbiosciences.com/quickblocker</a> <a href="http://www.merck4biosciences.com/quickblocker">www.merck4biosciences.com/quickblocker</a></td>
</tr>
<tr>
<td>Albumin, Bovine Serum, Fraction V</td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>12660</td>
<td><a href="http://www.emdbiosciences.com/bovineserum">www.emdbiosciences.com/bovineserum</a> <a href="http://www.merck4biosciences.com/bovineserum">www.merck4biosciences.com/bovineserum</a></td>
</tr>
<tr>
<td>PBS-TWEEN&reg; Tablets</td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>524653</td>
<td><a href="http://www.emdbiosciences.com/PBST">www.emdbiosciences.com/PBST</a> <a href="http://www.merck4biosciences.com/PBST">www.merck4biosciences.com/PBST</a></td>
</tr>
<tr>
<td>TBS-TWEEN&reg; Tablets</td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>524753</td>
<td><a href="http://www.emdbiosciences.com/TBST">www.emdbiosciences.com/TBST</a> <a href="http://www.merck4biosciences.com/TBST">www.merck4biosciences.com/TBST</a></td>
</tr>
<tr>
<td>SignalBoost&trade; Immunoreaction Enhancer Kit</td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>407207</td>
<td><a href="http://www.emdbiosciences.com/signalboost">www.emdbiosciences.com/signalboost</a> <a href="http://www.merck4biosciences.com/signalboost">www.merck4biosciences.com/signalboost</a></td>
</tr>
<tr>
<td>RapidStep&trade; ECL Reagent</td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>345818</td>
<td><a href="http://www.emdbiosciences.com/rapidstep">www.emdbiosciences.com/rapidstep</a> <a href="http://www.merck4biosciences.com/rapidstep">www.merck4biosciences.com/rapidstep</a></td>
</tr>		</tbody>
		</table>
		</div>

western blotting: sample preparation to detection

Western blotting é uma técnica analítica usada para detectar proteínas específicas em uma dada amostra de homogeneizado de tecido ou extrato. Ele usa eletroforese em gel para separar as proteínas nativas ou desnaturadas pelo comprimento do polipeptídeo (condições desnaturantes) ou pela estrutura 3-D da proteína (nativo / não-desnaturação condições). As proteínas são então transferidos para uma membrana (tipicamente de nitrocelulose ou PVDF), onde são detectados (detectado), utilizando anticorpos específicos para a proteína alvo.

Watch this Scientific Journal Video about Western Blotting: Sample Preparation to Detection at JoVE.com

Western Blotting: Sample Preparation to Detection

Western blotting é uma técnica analítica usada para detectar proteínas específicas em uma dada amostra de homogeneizado de tecido ou extrato.

Western Blotting: Preparação de amostras para detecção

Western blotting is an analytical technique used to detect specific proteins in a given sample of tissue homogenate or extract. It uses gel ...

western-blotting-sample-preparation-to-detection

Nanyang Technological University

Research

JoVE Journal

Biology

139.7K visualizações.  EMD Chemicals Inc.. Western blotting é uma técnica analítica usada para detectar proteínas específicas em uma dada amostra de homogeneizado de tecido ou extrato.

Vídeo: Western Blotting: Sample Preparation to Detection

MALDI Sample Preparation: the Ultra Thin Layer Method

This video demonstrates the preparation of an ultra-thin matrix/analyte layer for analyzing peptides and proteins by Matrix-Assisted Laser Desorption Ionization Mass Spectrometry (MALDI-MS) 1,2. The ultra-thin layer method involves the production of a substrate layer of matrix crystals (alpha-cyano-4-hydroxycinnamic acid) on the sample plate, which serves as a seeding ground for subsequent crystallization of a matrix/analyte mixture. Advantages of the ultra-thin layer method over other sample deposition approaches (e.g. dried droplet) are that it provides (i) greater tolerance to impurities such as salts and detergents, (ii) better resolution, and (iii) higher spatial uniformity. This method is especially useful for the accurate mass determination of proteins. The protocol was initially developed and optimized for the analysis of membrane proteins and used to successfully analyze ion channels, metabolite transporters, and receptors, containing between 2 and 12 transmembrane domains 2. Since the original publication, it has also shown to be equally useful for the analysis of soluble proteins. Indeed, we have used it for a large number of proteins having a wide range of properties, including those with molecular masses as high as 380 kDa 3. It is currently our method of choice for the molecular mass analysis of all proteins. The described procedure consistently produces high-quality spectra, and it is sensitive, robust, and easy to implement.

This video demonstrates the preparation of an ultra-thin matrix/analyte layer for analyzing peptides and proteins by Matrix-Assisted Laser Desorption Ionization Mass Spectrometry (MALDI-MS).

MALDI preparação da amostra: o método de Camada Ultra Thin

This video demonstrates the preparation of an ultra-thin matrix/analyte layer for analyzing peptides and proteins by Matrix-Assisted Laser Desorption ...

Biologia

Western Blotting Using the Invitrogen NuPage Novex Bis Tris MiniGels

Western Blotting (or immunoblotting) is a standard laboratory procedure allowing investigators to verify the expression of a protein, determine the relative amount of the protein present in different samples, and analyze the results of co-immunoprecipitation experiments. In this method, a target protein is detected with a specific primary antibody in a given sample of tissue homogenate or extract. Protein separation according to molecular weight is achieved using denaturing SDS-PAGE. After transfer to a membrane, the target protein is probed with a specific primary antibody and detected by chemiluminescence.
Since its first description, the western-blotting technique has undergone several improvements, including pre-cast gels and user-friendly equipment. In our laboratory, we have chosen to use the commercially available NuPAGE electrophoresis system from Invitrogen. It is an innovative neutral pH, discontinuous SDS-PAGE, pre-cast mini-gel system. This system presents several advantages over the traditional Laemmli technique including: i) a longer shelf life of the pre-cast gels ranging from 8 months to 1 year; ii) a broad separation range of molecular weights from 1 to 400 kDa depending of the type of gel used; and iii) greater versatility (range of acrylamide percentage, the type of gel, and the ionic composition of the running buffer).
The procedure described in this video article utilizes the Bis-Tris discontinuous buffer system with 4-12% Bis-Tris gradient gels and MES running buffer, as an illustration of how to perform a western-blot using the Invitrogen NuPAGE electrophoresis system. In our laboratory, we have obtained good and reproducible results for various biochemical applications using this western-blotting method.

This technical article describes a standard western-blotting procedure using the commercially available NuPAGE electrophoresis Mini-Gel system from Invitrogen.

Western Blotting Usando o Invitrogen NuPage Novex Bis Tris MiniGels

Western Blotting (or immunoblotting) is a standard laboratory procedure allowing investigators to verify the expression of a protein, determine the ...

Proteomic Sample Preparation from Formalin Fixed and Paraffin Embedded Tissue

Preserved clinical material is a unique source for proteomic investigation of human disorders. Here we describe an optimized protocol allowing large scale quantitative analysis of formalin fixed and paraffin embedded (FFPE) tissue. The procedure comprises four distinct steps. The first one is the preparation of sections from the FFPE material and microdissection of cells of interest. In the second step the isolated cells are lysed and processed using 'filter aided sample preparation' (FASP) technique. In this step, proteins are depleted from reagents used for the sample lysis and are digested in two-steps using endoproteinase LysC and trypsin. 
After each digestion, the peptides are collected in separate fractions and their content is determined using a highly sensitive fluorescence measurement. Finally, the peptides are fractionated on 'pipette-tip' microcolumns. The LysC-peptides are separated into 4 fractions whereas the tryptic peptides are separated into 2 fractions. In this way prepared samples allow analysis of proteomes from minute amounts of material to a depth of 10,000 proteins. Thus, the described workflow is a powerful technique for studying diseases in a system-wide-fashion as well as for identification of potential biomarkers and drug targets.

Archival formalin fixed and paraffin embedded (FFPE) clinical samples are valuable material for investigation of diseases. Here we demonstrate a sample preparation workflow allowing in-depth proteomic analysis of microdissected FFPE tissue.

Preparação de Amostras de proteômica fixados em formalina e embebidos em parafina Tissue

Preserved clinical material is a unique source for proteomic investigation of human disorders. Here we describe an optimized protocol allowing large scale ...

V3 Stain-free Workflow for a Practical, Convenient, and Reliable Total Protein Loading Control in Western Blotting

The western blot is a very useful and widely adopted lab technique, but its execution is challenging. The workflow is often characterized as a &#34;black box&#34; because an experimentalist does not know if it has been performed successfully until the last of several steps. Moreover, the quality of western blot data is sometimes challenged due to a lack of effective quality control tools in place throughout the western blotting process. Here we describe the V3 western workflow, which applies stain-free technology to address the major concerns associated with the traditional western blot protocol. This workflow allows researchers: 1) to run a gel in about 20-30 min; 2) to visualize sample separation quality within 5 min after the gel run; 3) to transfer proteins in 3-10 min; 4) to verify transfer efficiency quantitatively; and most importantly 5) to validate changes in the level of the protein of interest using total protein loading control. This novel approach eliminates the need of stripping and reprobing the blot for housekeeping proteins such as &#946;-actin, &#946;-tubulin, GAPDH, etc. The V3 stain-free workflow makes the western blot process faster, transparent, more quantitative&#160;and reliable.

V3 workflow is a western blot procedure using stain-free gels. The stain-free technology allows researchers to visualize protein separation quality, to verify the transfer efficiency, and most importantly, to validate the change in the protein of interest using total protein quantification as a reliable loading control.

Fluxo de trabalho livre de manchas V3 para um controle prático, conveniente e confiável de carregamento total de proteínas em blotting ocidental

The western blot is a very useful and widely adopted lab technique, but its execution is challenging. The workflow is often characterized as a &#34;black ...

The Fastest Western in Town: A Contemporary Twist on the Classic Western Blot Analysis

The Western blot techniques that were originally established in the late 1970s are still actively utilized today. However, this traditional method of Western blotting has several drawbacks that include low quality resolution, spurious bands, decreased sensitivity, and poor protein integrity. Recent advances have drastically improved numerous aspects of the standard Western blot protocol to produce higher qualitative and quantitative data. The Bis-Tris gel system, an alternative to the conventional Laemmli system, generates better protein separation and resolution, maintains protein integrity, and reduces electrophoresis to a 35 min run time. Moreover, the iBlot dry blotting system, dramatically improves the efficacy and speed of protein transfer to the membrane in 7 min, which is in contrast to the traditional protein transfer methods that are often more inefficient with lengthy transfer times. In combination with these highly innovative modifications, protein detection using infrared fluorescent imaging results in higher-quality, more accurate and consistent data compared to the standard Western blotting technique of chemiluminescence. This technology can simultaneously detect two different antigens on the same membrane by utilizing two-color near-infrared dyes that are visualized in different fluorescent channels. Furthermore, the linearity and broad dynamic range of fluorescent imaging allows for the precise quantification of both strong and weak protein bands. Thus, this protocol describes the key improvements to the classic Western blotting method, in which these advancements significantly increase the quality of data while greatly reducing the performance time of this experiment.

This protocol explores the latest advancements in performing Western blot analyses.&#160;These novel modifications employ a Bis-Tris gel system with a 35&#160;min electrophoresis run time, a 7&#160;min dry blotting transfer system, and infrared fluorescent protein detection and imaging that generates higher resolution, quality, sensitivity, and improved accuracy of Western data.

O mais rápido na Cidade Ocidental: um toque contemporâneo na Análise clássico Western Blot

The Western blot techniques that were originally established in the late 1970s are still actively utilized today. However, this traditional method of ...

Sample Preparation for Single Virion Atomic Force Microscopy and Super-resolution Fluorescence Imaging

Immobilization of virions to glass surfaces is a critical step in single virion imaging. Here we present a technique&#160;adopted from single molecule imaging assays which allows adhesion of single virions to glass surfaces with specificity. This preparation is based on grafting the surface of the glass with a mixture of PLL-g-PEG and PLL-g-PEG-Biotin, adding a layer of avidin, and finally creating virion anchors through attachment of biotinylated virus specific antibodies. We have applied this technique across a range of experiments including atomic force microscopy (AFM) and super-resolution fluorescence imaging. This sample preparation method results in a control adhesion of the virions to the surface.

The attachment of virions to a surface is a requirement for single virion imaging by Super-resolution fluorescence imaging or atomic force microscopy (AFM). Here we demonstrate a sample preparation method for controlled adhesion of virions to glass surfaces suitable for use in AFM and super-resolution fluorescence imaging.

Preparação da amostra para microscopia da força atômica de virion único e imagem de fluorescência de super-resolução

Immobilization of virions to glass surfaces is a critical step in single virion imaging. Here we present a technique&#160;adopted from single molecule ...

A Guide to Modern Quantitative Fluorescent Western Blotting with Troubleshooting Strategies

The late 1970s saw the first publicly reported use of the western blot, a technique for assessing the presence and relative abundance of specific proteins within complex biological samples. Since then, western blotting methodology has become a common component of the molecular biologists experimental repertoire. A cursory search of PubMed using the term &#8220;western blot&#8221; suggests that in excess of two hundred and twenty thousand published manuscripts have made use of this technique by the year 2014. Importantly, the last ten years have seen technical imaging advances coupled with the development of sensitive fluorescent labels which have improved sensitivity and yielded even greater ranges of linear detection. The result is a now truly Quantifiable Fluorescence based Western Blot (QFWB) that allows biologists to carry out comparative expression analysis with greater sensitivity and accuracy than ever before. Many &#8220;optimized&#8221; western blotting methodologies exist and are utilized in different laboratories. These often prove difficult to implement due to the requirement of subtle but undocumented procedural amendments. This protocol provides a comprehensive description of an established and robust QFWB method, complete with troubleshooting strategies.

The advancement of western blotting using fluorescence has allowed detection of subtle changes in protein expression enabling quantitative analyses. Here we describe a robust methodology for detection of a range of proteins across a variety of species and tissue types. A strategy to overcome common technical problems is also provided.

A Guide to Modern quantitativa fluorescente Western Blotting com estratégias de resolução de problemas

The late 1970s saw the first publicly reported use of the western blot, a technique for assessing the presence and relative abundance of specific proteins ...

Mucin Agarose Gel Electrophoresis: Western Blotting for High-molecular-weight Glycoproteins

Mucins, the heavily-glycosylated proteins lining mucosal surfaces, have evolved as a key component of innate defense by protecting the epithelium against invading pathogens. The main role of these macromolecules is to facilitate particle trapping and clearance while promoting lubrication of the mucosa. During protein synthesis, mucins undergo intense O-glycosylation and multimerization, which dramatically increase the mass and size of these molecules. These post-translational modifications are critical for the viscoelastic properties of mucus. As a result of the complex biochemical and biophysical nature of these molecules, working with mucins provides many challenges that cannot be overcome by conventional protein analysis methods. For instance, their high-molecular-weight prevents electrophoretic migration via regular polyacrylamide gels and their sticky nature causes adhesion to experimental tubing. However, investigating the role of mucins in health (e.g., maintaining mucosal integrity) and disease (e.g., hyperconcentration, mucostasis, cancer) has recently gained interest and mucins are being investigated as a therapeutic target. A better understanding of the production and function of mucin macromolecules may lead to novel pharmaceutical approaches, e.g., inhibitors of mucin granule exocytosis and/or mucolytic agents. Therefore, consistent and reliable protocols to investigate mucin biology are critical for scientific advancement. Here, we describe conventional methods to separate mucin macromolecules by electrophoresis using an agarose gel, transfer protein into nitrocellulose membrane, and detect signal with mucin-specific antibodies as well as infrared fluorescent gel reader. These techniques are widely applicable to determine mucin quantitation, multimerization and to test the effects of pharmacological compounds on mucins.

Mucins are high-molecular-weight glycoconjugates, with size ranging from 0.2 to 200 megadalton (MDa). As a result of their size, mucins do not penetrate conventional polyacrylamide gels and require larger pores for separation. We provide a detailed protocol for mucin agarose gel electrophoresis to assess relative quantification and study polymer assembly.

Mucina Agarose Gel Eletroforese: Western Blotting para glicoproteínas alta peso molecular


Mucins, the heavily-glycosylated proteins lining mucosal surfaces, have evolved as a key component of innate defense by protecting the epithelium against ...

Sample Preparation for Mass Cytometry Analysis

Mass cytometry utilizes antibodies conjugated with heavy metal labels, an approach that has greatly increased the number of parameters and opportunities for deep analysis well beyond what is possible with conventional fluorescence-based flow cytometry. As with any new technology, there are critical steps that help ensure the reliable generation of high-quality data. Presented here is an optimized protocol that incorporates multiple techniques for the processing of cell samples for mass cytometry analysis. The methods described here will help the user avoid common pitfalls and achieve consistent results by minimizing variability, which can lead to inaccurate data. To inform experimental design, the rationale behind optional or alternative steps in the protocol and their efficacy in uncovering new findings in the biology of the system being investigated is covered. Lastly, representative data is presented to illustrate expected results from the techniques presented here.

This article describes the collection and processing of samples for mass cytometry analysis.

Preparação de Amostras para Análise Mass Citometria

Mass cytometry utilizes antibodies conjugated with heavy metal labels, an approach that has greatly increased the number of parameters and opportunities ...

An Alternative Approach for Sample Preparation with Low Cell Number for TEM Analysis

Transmission electron microscopy (TEM) provides details of the cellular organization and ultrastructure. However, TEM analysis of rare cell populations, especially cells in suspension such as hematopoietic stem cells (HSCs), remains limited due to the requirement of a high cell number during sample preparation. There are a few cytospin or monolayer approaches for TEM analysis from scarce samples, but these approaches fail to get significant quantitative data from the limited number of cells. Here, an alternative and novel approach for sample preparation in TEM studies is described for rare cell populations that enables quantitative analysis.
A relatively low cell number, i.e., 10,000 HSCs, was successfully used for TEM analysis compared to the millions of cells typically used for TEM studies. In particular, Evans blue staining was performed after paraformaldehyde-glutaraldehyde (PFA-GA) fixation to visualize the tiny cell pellet, which facilitated embedding in agarose. Clusters of numerous cells were observed in ultra-thin sections. The cells had a well preserved morphology, and the ultra-structural details of the Golgi complex and several mitochondria were visible. This efficient, easy and reproducible protocol allows sample preparation from a low cell number and can be used for qualitative and quantitative TEM analysis on rare cell populations from limited biological samples.

Here, we present a protocol to prepare samples with low cell numbers for transmission electron microscopy (TEM) analysis.

Uma abordagem alternativa para preparação de amostras com baixo número de celular de Análise TEM

Transmission electron microscopy (TEM) provides details of the cellular organization and ultrastructure. However, TEM analysis of rare cell populations, ...