Agradecemos H. Fleming para a leitura crítica e edição do manuscrito. Este trabalho foi financiado por uma bolsa de Pós-Doutorado Misrock (TD) e NDSEG graduação comunhão (AP). SNB é um investigador HHMI.

1. Preparação celular <ol><li> Linhagens de células utilizando técnicas de cultura de células padrão. Neste experimento, foi utilizado OVCAR-8 células (NCI DCTD Tumor Repository, Frederick, MD). Crescer as células-alvo a uma confluência de 80-100%. </li><li> Incubar as células em 5 ml de tripsina durante 5 min, em seguida, adicionam-se 5 ml de meio RPMI + FBS para inactivar a tripsina. </li><li> Células colheita e contar com um hemocitômetro. Ressuspender em DMEM livre de fenol vermelho em uma concentração alvo de aproximadamente 5 x 10 7 células / ml, ou cerca de 200 mL por frasco. </li><li> Adicionar 15% de redução do fator de crescimento Matrigel (BD Biosciences) e manter a suspensão de células em gelo até a implantação. </li></ol> 2. Implantação do Tumor <ol><li> Anestesiar quatro semanas femininos Ncr / Nu ratos velhos que usam 3% isoflurano e esperar cerca de 5 min para garantir a anestesia profunda. Use pomada veterinário sobre os olhos para evitar a secura sob anestesia. </li><li> Carregar as células (100 ul por tumor) numa seringa de 1 ml e anexar uma 27 1/ 2 agulha de calibre. </li><li> Para cada um dos dois locais de injecção flanco traseiras bilaterais, levantar a pele suavemente com uma pinça para fazer uma tenda e injectar células na base. Tome cuidado para não penetrar muito profundamente, produzindo sangue. Use uma pinça para remover suavemente a seringa sem respingos. </li><li> Controlar o crescimento do tumor por dia, durante 10 - 20 dias até um diâmetro de tumor de 2-4 mm, é alcançado. </li></ol> 3. Bactérias Preparação <ol><li> Iniciar uma cultura durante a noite de bactérias em 3 ml de LB + ampicilina mídia a partir de um estoque C -80 congelador ou placa refrigerada. Neste experimento, utilizou-se S. typhimurium estirpe ELH430 (SL1344 PhoPQ-aroA-). </li><li> Na manhã seguinte, dilui-se a cultura de 1:100 em LB filtrou-se e crescer a DO600 0,4-0,6. </li><li> Girar e lavar 3 vezes em tampão fosfato salino (PBS) e ressuspender em definitivo uma DO600 de 0,1 (cerca de 1 x 10 7 células / ml). </li></ol> 4. Bactérias Injection <ol><li> Anestesiar o animal umd posição de lado, com a cauda apontada para sua mão dominante. Use pomada veterinário sobre os olhos para evitar a secura sob anestesia. </li><li> Dilatar a veia da cauda com água morna ou uma lâmpada de calor. </li><li> Carregar as bactérias (100 ul por rato) numa seringa de 1 ml e dobrar a ponta apenas menos do que 90 graus. </li><li> Alinhar a ponta da seringa com a veia da cauda, ​​penetrar a uma profundidade rasa (deve sentir nenhuma resistência), e injectar bactérias. Observe o deslocamento bloodflow para uma injeção de sucesso. </li></ol> 5. Rato de imagem <ol><li> Anestesiar animais na câmara de indução seguida, coloque cada mouse sobre a plataforma de imagem. Use pomada veterinário sobre os olhos para evitar a secura sob anestesia. Manter o posicionamento preciso para assegurar resultados quantitativos entre os pontos temporais. </li><li> Animais de imagem usando o sistema de imagem IVIS Spectrum (Caliper Life Sciences). Se uma imagem mais do que um lugar de animais, barreiras de luz entre eles para evitar cross-illuminação. Os animais devem ser fotografada em primeiro lugar no lado ventral para confirmar a localização de bactérias. </li><li> Imagem de animais dorsalmente usando IVIS a cada 2 horas, para a duração da experiência (36 horas). Gerar um campo de tempo para um dado ROI. </li></ol> 6. Quantificar Biodistribution bacteriana <ol><li> Eutanásia animais usando CO 2 e colocar na parte de trás em uma fralda absorvente. </li><li> Ligue o animal para expor os dois flancos traseiros tumores subcutâneos. Cortar o tecido da pele circundante, para separar e remover os tumores. Segurando o tumor com uma pinça, retire a pele com um movimento tesoura invertida. Quando a maior parte da pele foi separada, a remover completamente o tumor, usando uma pinça. </li><li> Coloque os órgãos em microtubos pré-pesados. Uma vez que a massa destes tubos pode variar significativamente, é importante pré-pesar de resultados quantitativos. </li></ol> 7. Quantificar Biodistribution bacteriana <ol><li> Para cada ponto de tempo, consumo e pesar os tumores. </li><li> Adicionar 500 ul de PBS + 15% de glicerol e homogeneizar utilizando um Tissue-Tearor (BioSpec). Lavar as homogeneizador 3 vezes com etanol entre amostras. </li><li> Gerar diluições em série e placa para contagem de colônias de bactérias. Para prato várias diluições em uma única placa, utilizar placas pré-seccionados. </li></ol>

<ol>
	<li>Hohmann, E. L., Oletta, C. A., Miller, S. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+a+phoP/phoQ-deleted,+aroA-deleted+live+oral+Salmonella+typhi+vaccine+strain+in+human+volunteers.">Evaluation of a phoP/phoQ-deleted, aroA-deleted live oral Salmonella typhi vaccine strain in human volunteers.</a> Vaccine. 14 (1), 19-24 (1996).</li><li>Leschner, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tumor+Invasion+of+Salmonella+enterica+Serovar+Typhimurium+Is+Accompanied+by+Strong+Hemorrhage+Promoted+by+TNF-alpha.">Tumor Invasion of Salmonella enterica Serovar Typhimurium Is Accompanied by Strong Hemorrhage Promoted by TNF-alpha.</a> Plos One. 4 (8), (2009).</li><li>Min, J. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+bioluminescence+imaging+of+tumor-targeting+bacteria+in+living+animals.">Quantitative bioluminescence imaging of tumor-targeting bacteria in living animals.</a> Nat. Protoc. 3 (4), 629-636 (2008).</li><li>Min, J. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Noninvasive+real-time+imaging+of+tumors+and+metastases+using+tumor-targeting+light-emitting+Escherichia+coli.">Noninvasive real-time imaging of tumors and metastases using tumor-targeting light-emitting Escherichia coli.</a> Mol. Imaging Biol. 10 (1), 54-61 (2008).</li><li>Choy, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+noninvasive+fluorescent+and+bioluminescent+small+animal+optical+imaging.">Comparison of noninvasive fluorescent and bioluminescent small animal optical imaging.</a> Biotechniques. 35 (5), 1022-1033 (2003).</li><li>Pawelek, J. M., Low, K. B., Bermudes, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tumor-targeted+Salmonella+as+a+novel+anticancer+vector.">Tumor-targeted Salmonella as a novel anticancer vector.</a> Cancer Research. 57 (20), 4537-4544 (1997).</li><li>Fu, X., Hoffman, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+ovarian+carcinoma+metastatic+models+constructed+in+nude+mice+by+orthotopic+transplantation+of+histologically-intact+patient+specimens.">Human ovarian carcinoma metastatic models constructed in nude mice by orthotopic transplantation of histologically-intact patient specimens.</a> Anticancer Res. 13 (2), 283-286 (1993).</li><li>Ozbudak, E. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+noise+in+the+expression+of+a+single+gene.">Regulation of noise in the expression of a single gene.</a> Nat. Genet. 31 (1), 69-73 (2002).</li><li>Elowitz, M. B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stochastic+gene+expression+in+a+single+cell.">Stochastic gene expression in a single cell.</a> Science. 297 (5584), 1183-1186 (2002).</li><li>Toso, J. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phase+I+study+of+the+intravenous+administration+of+attenuated+Salmonella+typhimurium+to+patients+with+metastatic+melanoma.">Phase I study of the intravenous administration of attenuated Salmonella typhimurium to patients with metastatic melanoma.</a> J. Clin. Oncol. 20 (1), 142-152 (2002).</li><li>Heimann, D. M., Rosenberg, S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Continuous+intravenous+administration+of+live+genetically+modified+salmonella+typhimurium+in+patients+with+metastatic+melanoma.">Continuous intravenous administration of live genetically modified salmonella typhimurium in patients with metastatic melanoma.</a> J. Immunother. 26 (2), 179-180 (2003).</li><li>Forbes, N. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Engineering+the+perfect+(bacterial)+cancer+therapy.">Engineering the perfect (bacterial) cancer therapy.</a> Nat. Rev. Cancer. 10 (11), 785-794 (2010).</li><li>Guo, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Targeting+tumor+gene+by+shRNA-expressing+Salmonella-mediated+RNAi.">Targeting tumor gene by shRNA-expressing Salmonella-mediated RNAi.</a> Gene Ther. 18 (1), 95-105 (2011).</li><li>Hoffman, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tumor-seeking+Salmonella+amino+acid+auxotrophs.">Tumor-seeking Salmonella amino acid auxotrophs.</a> Curr Opin Biotechnol. 22 (6), 917-923 (2011).</li><li>Nguyen, V. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetically+engineered+Salmonella+typhimurium+as+an+imageable+therapeutic+probe+for+cancer.">Genetically engineered Salmonella typhimurium as an imageable therapeutic probe for cancer.</a> Cancer Research. 70 (1), 18-23 (2010).</li><li>Zhao, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Targeted+therapy+with+a+Salmonella+typhimurium+leucine-arginine+auxotroph+cures+orthotopic+human+breast+tumors+in+nude+mice.">Targeted therapy with a Salmonella typhimurium leucine-arginine auxotroph cures orthotopic human breast tumors in nude mice.</a> Cancer Research. 66 (15), 7647-7652 (2006).</li><li>Danino, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+synchronized+quorum+of+genetic+clocks.">A synchronized quorum of genetic clocks.</a> Nature. 463 (7279), 326-330 (2010).</li><li>Anderson, J. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Environmentally+controlled+invasion+of+cancer+cells+by+engineered+bacteria.">Environmentally controlled invasion of cancer cells by engineered bacteria.</a> J. Mol. Biol. 355 (4), 619-627 (2006).</li><li>Hasty, J., McMillen, D., Collins, 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=Engineered+gene+circuits.">Engineered gene circuits.</a> Nature. 420 (6912), 224-230 (2002).</li><li>Prindle, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+sensing+array+of+radically+coupled+genetic+'biopixels'.">A sensing array of radically coupled genetic 'biopixels'.</a> Nature. 481 (7379), 39-44 (2012).</li><li>Xu, D. Q., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bacterial+delivery+of+siRNAs:+a+new+approach+to+solid+tumor+therapy.">Bacterial delivery of siRNAs: a new approach to solid tumor therapy.</a> Methods Mol. Biol. 487, 161-187 (2009).</li><li>Zheng, L. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tumor+amplified+protein+expression+therapy:+Salmonella+as+a+tumor-selective+protein+delivery+vector.">Tumor amplified protein expression therapy: Salmonella as a tumor-selective protein delivery vector.</a> Oncol. Res. 12 (3), 127-1235 (2000).</li><li>Kim, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+balanced-lethal+host-vector+system+based+on+glmS.">A novel balanced-lethal host-vector system based on glmS.</a> Plos One. 8 (3), e60511 (2013).</li><li>Prindle, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetic+Circuits+in+Salmonella+typhimurium.">Genetic Circuits in Salmonella typhimurium.</a> ACS Synthetic Biology. , (2012).</li><li>Danino, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+gene+expression+dynamics+of+tumor-targeted+bacteria.">In vivo gene expression dynamics of tumor-targeted bacteria.</a> ACS Synthetic Biology. , (2012).</li><li>Zhao, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spatial-temporal+imaging+of+bacterial+infection+and+antibiotic+response+in+intact+animals.">Spatial-temporal imaging of bacterial infection and antibiotic response in intact animals.</a> Proc. Natl. Acad. Sci. U.S.A. 98 (17), 9814-9818 (2001).</li></ol>

Não há conflitos de interesse declarados.

Usando este procedimento, somos capazes de gerar campos de tempo para o crescimento ea dinâmica de expressão de genes de bactérias que colonizam tumores. Embora estas medições são rotineiramente realizados in vitro em cultura descontínua ou dispositivos microfluidics, eles são muito mais difíceis de executar in vivo. Há diversas modificações que podem ser aplicadas a estes métodos. Quando foi utilizado o OVCAR-8 de linha de células para gerar os modelos de rat...

A biologia sintética progrediu rapidamente na última década e agora está posicionada para influenciar importantes problemas de energia e saúde. No entanto, a expansão na arena clínica tem sido retardado por questões de segurança e ausência de desenvolvimento de critérios de projeto para em circuitos genéticos in vivo. Acelerar aplicações médicas de alto impacto vai exigir a utilização de métodos que interagem diretamente com a infra-estrutura médica, circuitos genéticos que funcionam fora do ambiente de laboratório controlado, e hospedeiros microbianos seguras e clinicamente aceito. Um certo número de estirpes têm sido investigados para a terapia do cancro devido à sua capacidade para crescer preferencialmente em tumores. Estes incluíram C. novyi, E. coli, V. cholorae, B. longum, e S. typhimurium 3-8. S. typhimurium tem gerado interesse particular como eles exibiram segurança e tolerância em um certo número de ensaios clínicos em humanos 9-12. Estes bactericida<html> um foram inicialmente mostrado para criar efeitos anti-tumorais através da estimulação do sistema imunitário do hospedeiro e pela depleção de nutrientes necessários para o metabolismo de células do cancro. Produção de carga terapêutica foi adicionado mais tarde através de modificações genéticas. Embora estes estudos representam avanços importantes no uso de bactérias para as terapias do tumor, a maioria dos esforços actuais têm confiado na expressão de alto nível, que normalmente resulta na entrega de doses elevadas, os efeitos fora do alvo, e do desenvolvimento de resistência do hospedeiro 13-16 . Agora, a biologia sintética pode adicionar a produção de carga programável, utilizando circuitos genéticos computacionalmente desenhados que podem executar detecção avançadas e entrega 17-20. Estes circuitos podem ser concebidas para funcionar como sistemas de entrega que detectam estímulos específicos de tumores e auto-regulam a produção de cargas, conforme necessário. No entanto, o estudo da função destes circuitos in vivo tem sido até agora difícil. ve_content &quot;&gt; Desde plasmídeos são o quadro comum para circuitos sintéticos, nós descrevemos um método para caracterizar a dinâmica da expressão gênica baseada em plasmídeo in vivo utilizando um modelo de mouse. Estes métodos utilizam imagens luminescência time-lapse e medição quantitativa de biodistribuição. Juntos, essas abordagens fornecem uma estrutura para o estudo de redes baseadas em plasmídeo in vivo para aplicações clínicas.

<table border="1">
<tbody>
 <tr>
 <td>Name</td>
 <td>Company</td>
 <td>Catalog Number</td>
 <td>Comments</td>
 </tr>
 <tr>
 <td>1 ml syringe</td>
 <td>BD Biosciences</td>
 <td>309602</td>
 <td></td>
 </tr>
 <tr>
 <td>3/10 cc Insulin Syringe</td>
 <td>BD Biosciences</td>
 <td>309301</td>
 <td></td>
 </tr>
 <tr>
 <td>PrecisionGlide Needle </td>
 <td>BD Biosciences </td>
 <td>301629</td>
 <td></td>
 </tr>
 <tr>
 <td>RPMI Medium 1640 (1X), 
 liquid, with L-glutamine</td>
 <td>Invitrogen</td>
 <td>11875-119 </td>
 <td></td>
 </tr>
 <tr>
 <td>Ampicillin</td>
 <td>Sigma Aldrich</td>
 <td>A0166-5G</td>
 <td></td>
 </tr>
 <tr>
 <td>LB Agar Broth</td>
 <td>Sigma Aldrich</td>
 <td>L2897</td>
 <td></td>
 </tr>
 <tr>
 <td>Luria-Bertani broth</td>
 <td>BD Biosciences</td>
 <td>244610</td>
 <td></td>
 </tr>
 </tbody>
</table>

measuring growth and gene expression dynamics of tumor-targeted s. typhimurium bacteria

O objetivo desses experimentos é gerar dados de curso de tempo quantitativos sobre o crescimento ea dinâmica de expressão de genes de S. atenuada colônias bacterianas typhimurium crescimento dentro dos tumores. Geramos um modelo de xenoenxerto de tumores em ratos, por injecção subcutânea de uma linha de células de cancro do ovário humano, OVCAR-8 (NCI DCTD Tumor Repository, Frederick, MD). Nós transformado cepas atenuadas de S. bactérias typhimurium (ELH430: SL1344 phoPQ-1) com a luciferase expresso constitutivamente (luxCDABE) plasmídeo para visualização 2. Estas estirpes colonizar especificamente tumores, permanecendo essencialmente não virulento para o rato 1. Uma vez que os tumores eram mensuráveis ​​estabelecido, as bactérias foram injectados por via intravenosa através da veia da cauda, ​​com diferentes doses. Tumor-localizada, a expressão do gene bacteriano foi monitorizado em tempo real, ao longo de 60 horas utilizando umsistema de imagem in vivo (IVIS). Em cada ponto de tempo, os tumores foram excisados, homogeneizados e plaqueados para quantificar colónias bacterianas para a correlação com dados de expressão de genes. Juntos, estes dados produz uma medida quantitativa do crescimento in vivo de expressão do gene e da dinâmica do crescimento de bactérias no interior de tumores.

Usando este protocolo, somos capazes de gerar dados sobre o crescimento in vivo e da dinâmica de expressão de genes de bactérias específicas do tumor. O fluxo de trabalho global está resumida na figura 1. Na primeira etapa, nós injetar bactérias (verde) ea imagem do animal usando IVIS para medir a expressão do gene com luminescência (azul) como repórter. Em seguida, na segunda etapa, de consumo, homogeneizar e tumores placa par...

Watch this Scientific Journal Video about Measuring Growth and Gene Expression Dynamics of Tumor-Targeted S. Typhimurium Bacteria at JoVE.com

Measuring Growth and Gene Expression Dynamics of Tumor-Targeted S. Typhimurium Bacteria

O objetivo desses experimentos é gerar dados de curso de tempo quantitativos sobre o crescimento ea dinâmica de expressão de genes de atenuado<em&gt; S. typhimurium</em&gt; Colônias de bactérias que crescem dentro dos tumores. Este vídeo aborda a preparação de células tumorais e implantação, preparação e injeção de bactérias, a imagem inteira animal-luminescência, a excisão do tumor, e contagem de colônias de bactérias.

Medindo o Crescimento e Expressão Gênica Dynamics do Tumor-Targeted<em&gt; S. Typhimurium</em&gt; Bactérias

The goal of these experiments is to generate quantitative time-course data on the growth and gene expression dynamics of attenuated S. typhimurium ...

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JoVE Journal

Immunology and Infection

Measuring Growth and Gene Expression Dynamics of Tumor-Targeted S. Typhimurium Bacteria

12.0K visualizações.  Massachusetts Institute of Technology. O objetivo desses experimentos é gerar dados de curso de tempo quantitativos sobre o crescimento ea dinâmica de expressão de genes de atenuado S. typhimurium Colônias de bactérias que crescem dentro dos tumores. Este vídeo aborda a preparação de células tumorais e implantação, preparação e injeção de bactérias, a imagem inteira animal-luminescência, a excisão do tumor, e contagem de colônias de bactérias.

Vídeo: Measuring Growth and Gene Expression Dynamics of Tumor-Targeted S. Typhimurium Bacteria

Using Fluorescent Proteins to Visualize and Quantitate Chlamydia Vacuole Growth Dynamics in Living Cells

The obligate intracellular bacterium Chlamydia elicits a great burden on global public health. C.&#160;trachomatis is the leading bacterial cause of sexually transmitted infection and also the primary cause of preventable blindness in the world. An essential determinant for successful infection of host cells by Chlamydia is the bacterium's ability to manipulate host cell signaling from within a novel, vacuolar compartment called the inclusion. From within the inclusion, Chlamydia acquire nutrients required for their 2-3 day developmental growth, and they additionally secrete a panel of effector proteins onto the cytosolic face of the vacuole membrane and into the host cytosol. Gaps in our understanding of Chlamydia biology, however, present significant challenges for visualizing and analyzing this intracellular compartment. Recently, a reverse-imaging strategy for visualizing the inclusion using GFP expressing host cells was described. This approach rationally exploits the intrinsic impermeability of the inclusion membrane to large molecules such as GFP. In this work, we describe how GFP- or mCherry-expressing host cells are generated for subsequent visualization of chlamydial inclusions. Furthermore, this method is shown to effectively substitute for costly antibody-based enumeration methods, can be used in tandem with other fluorescent labels, such as GFP-expressing Chlamydia, and can be exploited to derive key quantitative data about inclusion membrane growth from a range of Chlamydia species and strains.

Using Fluorescent Proteins to Visualize and Quantitate Chlamydia Vacuole Growth Dynamics in Living Cells

A live cell fluorescent protein based method for illuminating cellular vacuoles (inclusions) containing Chlamydia is described. This strategy enables rapid, automated determination of Chlamydia infectivity in samples and can be used to quantitatively investigate inclusion growth dynamics.

Usando proteínas fluorescentes para visualizar e Quantificar<em&gt; Chlamydia</em&gt; Vacúolo Crescimento Dynamics em células vivas

The obligate intracellular bacterium Chlamydia elicits a great burden on global public health. C.&#160;trachomatis is the leading bacterial cause of ...

Imunologia e Infecção

Vaccinia Reporter Viruses for Quantifying Viral Function at All Stages of Gene Expression

Poxviruses are a family of double stranded DNA viruses that include active human pathogens such as monkeypox, molluscum contagiousum, and Contagalo virus. The family also includes the smallpox virus, Variola. Due to the complexity of poxvirus replication, many questions still remain regarding their gene expression strategy. In this article we describe the conceptualization and usage of recombinant vaccinia viruses that enable real-time measurement of single and multiple stages of viral gene expression in a high-throughput format. This is enabled through the use of spectrally distinct fluorescent proteins as reporters for each of three stages of viral replication. These viruses provide a high signal-to-noise ratio while retaining stage specific expression patterns, enabling plate-based assays and microscopic observations of virus propagation and replication. These tools have uses for antiviral discovery, studies of the virus-host interaction, and evolutionary biology.

We describe the usage of a fluorescent reporter vaccinia virus that enables real-time measurement of viral infectivity and gene expression through the stage-specific expression of spectrally distinct reporter fluorophores. We detail a plate-based method for accurately identifying the stage at which virus replication is affected in response to small molecule inhibition.

Repórter Vaccinia vírus para quantificar Função Viral em todas as fases da Expressão Gênica

Poxviruses are a family of double stranded DNA viruses that include active human pathogens such as monkeypox, molluscum contagiousum, and Contagalo virus. ...

A Protocol to Infect Caenorhabditis elegans with Salmonella typhimurium

In the last decade, C. elegans has emerged as an invertebrate organism to study interactions between hosts and pathogens, including the host defense against gram-negative bacterium Salmonella typhimurium. Salmonella establishes persistent infection in the intestine of C. elegans and results in early death of infected animals. A number of immunity mechanisms have been identified in C. elegans to defend against Salmonella infections. Autophagy, an evolutionarily conserved lysosomal degradation pathway, has been shown to limit the Salmonella replication in C. elegans and in mammals. Here, a protocol is described to infect C. elegans with Salmonella typhimurium, in which the worms are exposed to Salmonella for a limited time, similar to Salmonella infection in humans. Salmonella infection significantly shortens the lifespan of C. elegans. Using the essential autophagy gene bec-1 as an example, we combined this infection method with C. elegans RNAi feeding approach and showed this protocol can be used to examine the function of C. elegans host genes in defense against Salmonella infection. Since C. elegans whole genome RNAi libraries are available, this protocol makes it possible to comprehensively screen for C. elegans genes that protect against Salmonella and other intestinal pathogens using genome-wide RNAi libraries.

A Protocol to Infect Caenorhabditis elegans with Salmonella typhimurium

C. elegans has emerged as a new genetic model to study host-pathogen interactions. Here we describe a protocol to infect C. elegans with Salmonella typhimurium coupled with the double-strand RNAi interference technique to examine the role of host genes in defense against Salmonella infection.

Um protocolo para infectar<em&gt; Caenorhabditis elegans</em&gt; Com<em&gt; Salmonella typhimurium</em

In the last decade, C. elegans has emerged as an invertebrate organism to study interactions between hosts and pathogens, including the host defense ...

High-throughput Assay to Phenotype Salmonella enterica Typhimurium Association, Invasion, and Replication in Macrophages

Salmonella species are zoonotic pathogens and leading causes of food borne illnesses in humans and livestock1. Understanding the mechanisms underlying Salmonella-host interactions are&#160;important to elucidate the molecular pathogenesis of Salmonella infection. The Gentamicin protection assay to phenotype Salmonella association, invasion and replication in phagocytic cells was adapted to allow high-throughput screening to define the roles of deletion mutants of Salmonella enterica serotype Typhimurium in host interactions using RAW 264.7 murine macrophages. Under this protocol, the variance in measurements is significantly reduced compared to the standard protocol, because wild-type and multiple mutant strains can be tested in the same culture dish and at the same time. The use of multichannel pipettes increases the throughput and enhances precision. Furthermore, concerns related to using less host cells per well in 96-well culture dish were addressed. Here, the protocol of the modified in vitro Salmonella invasion assay using phagocytic cells was successfully employed to phenotype 38 individual Salmonella deletion mutants for association, invasion and intracellular replication. The in vitro phenotypes are presented, some of which were subsequently confirmed to have in vivo phenotypes in an animal model. Thus, the modified, standardized assay to phenotype Salmonella association, invasion and replication in macrophages with high-throughput capacity could be utilized more broadly to study bacterial-host interactions.

High-throughput Assay to Phenotype Salmonella enterica Typhimurium Association, Invasion, and Replication in Macrophages

A high-throughput assay to in vitro phenotype Salmonella or other bacterial association, invasion, and replication in phagocytic cells with high-throughput capacity was developed. The method was employed to evaluate Salmonella gene knockout mutant strains for their involvements in host-pathogen interactions.

De alta capacidade: Ensaio para Fenótipo<em&gt; Salmonella enterica</em&gt; Typhimurium Association, invasão e replicação em macrófagos

Salmonella species are zoonotic pathogens and leading causes of food borne illnesses in humans and livestock1. Understanding the mechanisms underlying ...

Isolation of Murine Peritoneal Macrophages to Carry Out Gene Expression Analysis Upon Toll-like Receptors Stimulation

During infection and inflammation, circulating monocytes leave the bloodstream and migrate into tissues, where they differentiate into macrophages. Macrophages express surface Toll-like receptors (TLRs), which recognize molecular patterns conserved through evolution in a wide range of microorganisms. TLRs play a central role in macrophage activation which is usually associated with gene expression alteration. Macrophages are critical in many diseases and have emerged as attractive targets for therapy. In the following protocol, we describe a procedure to isolate murine peritoneal macrophages using Brewer&#8217;s thioglycollate medium. The latter will boost monocyte migration into the peritoneum, accordingly this will raise macrophage yield by 10-fold. Several studies have been carried out using bone marrow, spleen or peritoneal derived macrophages. However, peritoneal macrophages were shown to be more mature upon isolation and are more stable in their functionality and phenotype. Thus, macrophages isolated from murine peritoneal cavity present an important cell population that can serve in different immunological and metabolic studies. Once isolated, macrophages were stimulated with different TLR ligands and consequently&#160;gene expression was evaluated.

We describe here a simple protocol to isolate murine peritoneal macrophages. This procedure is followed by RNA extraction to carry out gene expression analysis upon Toll-like receptors stimulation.

Isolamento de Murino macrófagos peritoniais de Cumprir a análise de expressão gênica Após Toll-like receptors Estimulação

During infection and inflammation, circulating monocytes leave the bloodstream and migrate into tissues, where they differentiate into macrophages. ...

Gene Expression Profiling of Infecting Microbes Using a Digital Bar-coding Platform

For most mammalian pathogens, gene expression profiling studies have been limited by technical difficulties to accurately quantify pathogen gene transcripts from infected tissues. Pathogen RNA constitutes a tiny portion of the total RNA isolated from infected tissue samples. Both microarray and RNAseq technologies have difficulties in generating reliable reads for weakly expressed pathogen genes. Mutant pathogen strains with reduced in vivo proliferation pose an even bigger challenge. Here we describe an in vivo gene expression profiling protocol that is very fast, extremely sensitive and highly reproducible. We developed this protocol during our investigation of the fungal pathogen Candida albicans in a murine model of hematogenously disseminated candidiasis. Using this protocol, we have documented time courses of dynamically regulated C. albicans gene expression during kidney infection, and discovered unexpected features of gene expression responses to antifungal drug treatment in vivo.

We developed a protocol that is fast, sensitive and reproducible for pathogen gene expression profiling during an infection.

Gene Expression Profiling de micróbios Contaminando utilizando uma plataforma digital de codificação em barra

For most mammalian pathogens, gene expression profiling studies have been limited by technical difficulties to accurately quantify pathogen gene ...

A Method to Assess Fc-mediated Effector Functions Induced by Influenza Hemagglutinin Specific Antibodies

Antibodies play a crucial role in coupling the innate and adaptive immune responses against viral pathogens through their antigen binding domains and Fc-regions. Here, we describe how to measure the activation of Fc effector functions by monoclonal antibodies targeting the influenza virus hemagglutinin with the use of a genetically engineered Jurkat cell line expressing an activating type 1 Fc-Fc&#947;R. Using this method, the contribution of specific Fc-Fc&#947;R interactions conferred by immunoglobulins can be determined using an in vitro assay.

We describe a method to measure the activation of Fc-mediated effector functions by antibodies that target the influenza virus hemagglutinin. This assay can also be adapted to assess the ability of monoclonal antibodies or polyclonal sera targeting other viral surface glycoproteins to induce Fc-mediated immunity.

Um método para avaliar funções efetoras mediada por Fc induzidas por anticorpos específicos de hemaglutinina de gripe

Antibodies play a crucial role in coupling the innate and adaptive immune responses against viral pathogens through their antigen binding domains and ...

Isolation of Salmonella typhimurium-containing Phagosomes from Macrophages

Salmonella typhimurium is a facultative intracellular bacterium that causes gastroenteritis in humans. After invasion of the lamina propria, S. typhimurium bacteria are quickly detected and phagocytized by macrophages, and contained in vesicles known as phagosomes in order to be degraded. Isolation of S. typhimurium-containing phagosomes have been widely used to study how S. typhimurium infection alters the process of phagosome maturation to prevent bacterial degradation. Classically, the isolation of bacteria-containing phagosomes has been performed by sucrose gradient centrifugation. However, this process is time-consuming, and requires specialized equipment and a certain degree of dexterity. Described here is a simple and quick method for the isolation of S. typhimurium-containing phagosomes from macrophages by coating the bacteria with biotin-streptavidin-conjugated magnetic beads. Phagosomes obtained by this method can be suspended in any buffer of choice, allowing the utilization of isolated phagosomes for a broad range of assays, such as protein, metabolite, and lipid analysis. In summary, this method for the isolation of S. typhimurium-containing phagosomes is specific, efficient, rapid, requires minimum equipment, and is more versatile than the classical method of isolation by sucrose gradient-ultracentrifugation.

Isolation of Salmonella typhimurium-containing Phagosomes from Macrophages

We describe here a simple and quick method for the isolation of Salmonella typhimurium-containing phagosomes from macrophages by coating the bacteria with biotin and streptavidin.

Isolamento de Salmonella typhimurium-contendo Phagosomes de macrófagos

Salmonella typhimurium is a facultative intracellular bacterium that causes gastroenteritis in humans. After invasion of the lamina propria, S. ...

Live-Cell Fluorescence Microscopy to Investigate Subcellular Protein Localization and Cell Morphology Changes in Bacteria

Investigations of factors influencing cell division and cell shape in bacteria are commonly performed in conjunction with high-resolution fluorescence microscopy as observations made at a population level may not truly reflect what occurs at a single cell level. Live-cell timelapse microscopy allows investigators to monitor the changes in cell division or cell morphology which provide valuable insights regarding subcellular localization of proteins and timing of gene expression, as it happens, to potentially aid in answering important biological questions. Here, we describe our protocol to monitor phenotypic changes in Bacillus subtilis and Staphylococcus aureus using a high-resolution deconvolution microscope. The objective of this report is to provide a simple and clear protocol that can be adopted by other investigators interested in conducting fluorescence microscopy experiments to study different biological processes in bacteria as well as other organisms.

This article provides a step-by-step guide to investigate protein subcellular localization dynamics and to monitor morphological changes using high-resolution fluorescence microscopy in Bacillus subtilis and Staphylococcus aureus.

Microscopia de Fluorescência de células vivas para investigar a localização de proteínas subcelulares e alterações da morfologia celular nas bactérias

Investigations of factors influencing cell division and cell shape in bacteria are commonly performed in conjunction with high-resolution fluorescence ...

NF-&#954;B-dependent Luciferase Activation and Quantification of Gene Expression in Salmonella Infected Tissue Culture Cells

The dimeric transcription factor NF-&#954;B regulates many cellular response pathways, including inflammatory pathways by inducing the expression of various cytokines and chemokines. NF-&#954;B is constitutively expressed and is sequestered in the cytosol by the inhibitory protein nuclear factor of kappa light polypeptide gene enhancer in B cells inhibitor, alpha (I&#954;B&#945;). Activation of NF-&#954;B requires the degradation of I&#954;B&#945;, which then exposes a nuclear localization signal on NF-&#954;B and promotes its trafficking to the nucleus. Once in the nucleus, NF-&#954;B binds to the promotor region of NF-&#954;B target genes such as interleukin 6 (IL-6) and IL-23, to promote their expression.
The activation of NF-&#954;B occurs independently of transcription or translation. Therefore, the activation state of NF-&#954;B must be measured either by quantifying NF-&#954;B specifically in the nucleus, or by quantifying expression of NF-&#954;B target genes. In this protocol, cells stably transfected with an NF-&#954;B::luciferase reporter construct are assayed for NF-&#954;B activation using in vitro tissue culture techniques. These cells are infected with Salmonella Typhimurium to activate NF-&#954;B, which traffics to the nucleus and binds to &#954;B sites in the promoter region of luciferase, inducing its expression. Cells are lysed and analyzed with the luciferase assay system. The amount of luciferase produced by the cells correlates with the intensity of the luminescence signal, which is detected by a plate reader. The luminescence signal generated by this procedure provides a quick and highly sensitive method by which to assess NF-&#954;B activation under a range of conditions. This protocol also utilizes quantitative reverse transcription PCR (RT-qPCR) to detect relative mRNA levels that are indicative of gene expression.

NF-&amp;#954;B-dependent Luciferase Activation and Quantification of Gene Expression in &lt;em&gt;Salmonella&lt;/em&gt; Infected Tissue Culture Cells

Here, we present a protocol to quickly and easily measure nuclear factor kappa-light-chain-enhancer of activated B cells (NF-&#954;B) activation in cell lines expressing NF-&#954;B::luciferase reporter constructs, via measurements of luminescence in the cell lysate. Additionally, gene expression is determined via RT-qPCR isolated from cells infected with Salmonella Typhimurium.

NF-κB-dependente Luciferase Ativação e Quantificação da Expressão Gênica em Salmonella Células Cultura dos Tecidos Infectados

The dimeric transcription factor NF-&#954;B regulates many cellular response pathways, including inflammatory pathways by inducing the expression of ...