Os autores gostariam de agradecer a todos os membros do BEI para o desenvolvimento desta técnica. Esta pesquisa foi apoiada em parte por Grant-in-Aid para a Investigação Científica em Áreas Prioritárias &quot;Traffic Membrane&quot; (HO), e &quot;Matriz de Fenômenos Infecciosas&quot; (KH), Jovens Cientistas (SF e KH), e da Investigação Científica (HO ), Investigação Científica e em áreas inovadoras &quot;Logística intracelular&quot; (HO), do Ministério da Educação, Cultura, Desporto, Ciência e Tecnologia do Japão.

1. Preparação de células bacterianas <ol><li> Glicerol Streak abastecido bactérias fluorescentes (GFP como expressar S. Typhimurium) em uma placa de ágar LB contendo 100 mg / ml de ampicilina. </li><li> Cultura colônia a partir de um único agar LB durante a noite em 2 ml de meio LB novo. </li><li> Adicionar 0,5 ml de cultura bacteriana e 4,5 ml de meio LB e incubar novos até densidade óptica de 1,0 a 600 nm é atingido. </li><li> Células bacterianas colheita por centrifugação (3.000 xg, 5 min, 4 ° C). </li><li> Desprezar o sobrenadante e lavar duas vezes com 5,0 ml de solução salina estéril tampão fosfato (PBS). </li><li> Ressuspender pellet de bactérias com 5 ml de PBS, e usar 50 ul da suspensão contendo cerca de 10 7 unidades formadoras de colônia (UFC) como o inóculo. </li><li> No caso de utilizar bactérias fluorescente etiquetado, as células bacterianas foram marcados por fluorescência reagente rotulagem de acordo com protocolo padrão. </li></ol> 2. Anesthesia <ol><li> Encha uma pequena caixa de plástico (10 x 10 x 5 cm) com 5% (v / v) isoflurano vaporizado misturado com o ar (vazão: 200 ml / min). </li><li> Anestesiar oito a dezesseis fraco de idade, os ratos machos ou fêmeas na caixa. </li><li> Mova o rato para uma mesa de autópsia após a anestesia. </li><li> Continuamente anestesiar os ratos de 2% (v / v) isoflurano vaporizado misturado com o ar (vazão: 200 ml / min) (Figura 1). Este é um procedimento terminal. </li></ol> 3. Ensaio de Peyer ligada a alça de patch <ol><li> 1 centímetro inciso da pele abdominal e depois cortar o peritônio abdominal de um rato anestesiado e tirar o intestino delgado, contendo o patch de Peyer. </li><li> Ligadura do intestino com fios de costura, tendo o cuidado de evitar vasos sanguíneos. Nota: apenas ligam um lado do intestino, e deixar o outro lado solto. </li><li> Injetar 50 mL de suspensão bacteriana ou PBS (controle) com uma seringa em loop Peyer ligada a mancha na s soltaide do intestino (Figura 2). </li><li> Bind lado solto, e perto do abdômen do rato com um clipe. </li><li> Após 1 h, retire o loop de patch ligada Peyer, e euthanize o mouse por deslocamento cervical. </li><li> Remendo Peyer consumo a partir de loop Peyer ligada a patch. </li><li> Piscando do lado apical do patch de Peyer por 1 ml de PBS com o uso de seringa conectada a uma agulha para retirar líquido da mucosa em excesso e bactérias. Piscando o patch de Peyer um adicional de duas vezes. </li></ol> 4. Coloração montagem toda e análise microscópica confocal do patch de Peyer <ol><li> Fix patch de Peyer no BD solução Cytofix / Cytoperm em gelo por 1 hora. </li><li> Lavar correção de Peyer três vezes com 1 ml de BD Perm / Tampão de lavagem por 5 min, e então bloco com 1 ml de tampão de bloqueio contendo 0,1% (w / v) saponina, 0,2% (w / v) BSA em PBS por 30 min em gelo. </li><li> Adicionar 200 vezes diluído anti-rato GP2 anticorpo monoclonal (5 mg / ml) para a amostra para detectarCélulas M. </li><li> Incubar por 2 horas em temperatura ambiente ou durante a noite a 4 ° C. </li><li> Lavar três vezes com 1 ml de frio PBS, em seguida, adicione 200 vezes diluído anti-rato IgG conjugado com DyLight549 (20 mcg / ml) com o modelo. </li><li> Incubar amostra em gelo por 2 horas. </li><li> Lavar três vezes com 1 ml de frio PBS, em seguida, adicione 50 vezes diluída Alexa 633 faloidina conjugado com o modelo para detectar F-actina. </li><li> Incubar no gelo por 2 hrs. </li><li> Lave suavemente com 1 ml de frio PBS. Em seguida, coloque 3-4 pedaços de vidro da tampa circular em um slide, e incorporar as amostras em uma solução de 30% de glicerol em PBS na lâmina (Figura 3). </li><li> Observar espécimes com um microscópio de varredura confocal DM-IRE2 laser ou um microscópio DeltaVision deconvolução Restauração. </li></ol> 5. Resultados representativos: O exemplo de amostra de um rato ligado ensaio de Peyer ciclo patch com GFP-S. Typhimurium foi observada com um microscópio deconvolução Restauração DeltaVision (Figura 4). GFP-S. Typhimurium é transcytosed pela GP2 células + M. Um patch Peyer rato ensaio de alça intestinal pode identificar o tipo de bactérias comensais ou patogênicos que podem ser transcytosed pelas células M. <img alt="Figura 1" src="/files/ftp_upload/3225/3225fig1.jpg" /> Figura 1. Anestesia de ratos sob condição isoflurano vaporizado. Isoflurano vaporizado foi fornecido por um aparelho de anestesia dedicada (lado esquerdo). <img alt="Figura 2" src="/files/ftp_upload/3225/3225fig2.jpg" /> Figura 2. Resumo do ensaio Peyer ligadura de alça intestinal de patch. A suspensão bacteriana foi fluorescentes injetado por seringa no circuito ligado Peyer do patch do lado solto do intestino. <img alt="Figura 3" src="/files/ftp_upload/3225/3225fig3.jpg" /> <strong&gt; Figura 3. Monte dos espécimes. Os espécimes foram incluídos em uma solução 30% de glicerol em PBS em um slide especial, no qual uma placa de plástico perfurado (1 mm de espessura) foi obrigado por um agente adesivo em uma lâmina de vidro. <img alt="Figura 4" src="/files/ftp_upload/3225/3225fig4.jpg" /> Figura 4. Exemplo de um rato ligado ensaio de Peyer ciclo patch com GFP-S. Typhimurium. GP2, que é relatado como marcador de células específicas M 5, foi corado com anticorpos anti-rato GP2 (Red). O espécime foi observado com um microscópio deconvolução DeltaVision Restauração. GFP-expressando S. Typhimurium foi co-localizada com GP2 na membrana plasmática apical de células M e nas vesículas subapical citoplasmática (setas). Ponto de vista, superior apical. Fundo e laterais, vista lateral. Barra de escala: 10 mM.

<ol>
	<li>Fagarasan, S., Honjo, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intestinal+IgA+synthesis:+regulation+of+front-line+body+defences.">Intestinal IgA synthesis: regulation of front-line body defences.</a> Nat. Rev. Immunol. 3, 63-72 (2003).</li><li>Hapfelmeier, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reversible+microbial+colonization+of+germ-free+mice+reveals+the+dynamics+of+IgA+immune+responses.">Reversible microbial colonization of germ-free mice reveals the dynamics of IgA immune responses.</a> Science. 328, 1705-1709 (2010).</li><li>Owen, R. L., Jones, A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Epithelial+cell+specialization+within+human+Peyer's+patches:+an+ultrastructural+study+of+intestinal+lymphoid+follicles.">Epithelial cell specialization within human Peyer's patches: an ultrastructural study of intestinal lymphoid follicles.</a> Gastroenterology. 66, 189-203 (1974).</li><li>Neutra, M. R., Mantis, N. J., Kraehenbuhl, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Collaboration+of+epithelial+cells+with+organized+mucosal+lymphoid+tissues.">Collaboration of epithelial cells with organized mucosal lymphoid tissues.</a> Nat. Immunol. 2, 1004-1009 (2001).</li><li>Hase, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Uptake+through+glycoprotein+2+of+FimH(+)+bacteria+by+M+cells+initiates+mucosal+immune+response.">Uptake through glycoprotein 2 of FimH(+) bacteria by M cells initiates mucosal immune response.</a> Nature. 462, 226-230 (2009).</li><li>Punyashthiti, K., Finkelstein, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enteropathogenicity+of+Escherichia+coli.+I.+Evaluation+of+mouse+intestinal+loops.">Enteropathogenicity of Escherichia coli. I. Evaluation of mouse intestinal loops.</a> Infect. Immun. 4, 473-478 (1971).</li><li>Owen, R. L., Pierce, N. F., Apple, R. T., Cray, W. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=M+cell+transport+of+Vibrio+cholerae+from+the+intestinal+lumen+into+Peyer's+patches:+a+mechanism+for+antigen+sampling+and+for+microbial+transepithelial+migration.">M cell transport of Vibrio cholerae from the intestinal lumen into Peyer's patches: a mechanism for antigen sampling and for microbial transepithelial migration.</a> J. Infect. Dis. 153, 1108-1118 (1986).</li><li>Owen, R. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=M+cells--entryways+of+opportunity+for+enteropathogens.">M cells--entryways of opportunity for enteropathogens.</a> J. Exp. Med. 180, 7-9 (1994).</li><li>Clark, M. A., Hirst, B. H., Jepson, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=M-cell+surface+beta1+integrin+expression+and+invasin-mediated+targeting+of+Yersinia+pseudotuberculosis+to+mouse+Peyer's+patch+M+cells.">M-cell surface beta1 integrin expression and invasin-mediated targeting of Yersinia pseudotuberculosis to mouse Peyer's patch M cells.</a> Infect. Immun. 66, 1237-1243 (1998).</li><li>Jensen, V. B., Harty, J. T., Jones, B. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interactions+of+the+invasive+pathogens+Salmonella+typhimurium,+Listeria+monocytogenes,+and+Shigella+flexneri+with+M+cells+and+murine+Peyer's+patches.">Interactions of the invasive pathogens Salmonella typhimurium, Listeria monocytogenes, and Shigella flexneri with M cells and murine Peyer's patches.</a> Infect. Immun. 66, 3758-3766 (1998).</li><li>Nagai, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+Peyer's+patches+in+the+induction+of+Helicobacter+pylori-induced+gastritis.">Role of Peyer's patches in the induction of Helicobacter pylori-induced gastritis.</a> Proc. Natl. Acad. Sci. U. S. A. 104, 8971-8976 (2007).</li></ol>

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<html> O tempo de incubação do patch Peyer ligada com suspensão bacteriana é geralmente para 1 hora de observar a incorporação de bactérias nas células M. Em caso de 4 horas de incubação, as bactérias são muitas vezes detectados na zona de células T de placas de Peyer. Como a anestesia inalatória com isoflurano vaporizado poderia manter ratos estável, o tempo de incubação do patch Peyer ligada com suspensão bacteriana é extensível para observar as bactérias que se movem em T-cell zona no patch de Pey...

<table border="1"><tbody><tr><th> Nome do reagente </th><th> Companhia </th><th> Número de catálogo </th><th> Comments (opcional) </th></tr><tr><td> LB Agar Ampicilina- 100 </td><td> SIGMA </td><td> L5667 </td><td></td></tr><tr><td> Cy3 mono-Reativa Pacote de corante </td><td> GE Healthcare </td><td> PA23001 </td><td></td></tr><tr><td> Alexa Fluor 350 ácido carboxílico, succinimidyl ester </td><td> Invitrogen </td><td> A10168 </td><td></td></tr><tr><td> Anestesia inalatória aparelho </td><td> Shinano Seisakusho </td><td> SN-487 </td><td></td></tr><tr><td> Fixação e Permeabilização Solução </td><td> BD </td><td> 554722 </td><td></td></tr><tr><td> Rato Anti Glicoproteína 2 anticorpo </td><td> MBL </td><td>D278-3 </td><td> 200 vezes de diluição (5μg/ml) </td></tr><tr><td> Goat Anti-IgG de rato, F (ab &#39;) 2 fragmento específico </td><td> Jackson ImmunoResearch </td><td> 112-505-006 </td><td> 200 vezes de diluição (20μg/ml) </td></tr><tr><td> Alexa Fluor 633 Faloidina </td><td> Sondas moleculares </td><td> A22284 </td><td> 50 vezes de diluição </td></tr><tr><td> Confocal a laser microscópio de varredura </td><td> Leica Microsystems </td><td> DMIRE2 </td><td></td></tr><tr><td> DeltaVision Restauração deconvolução microscópio </td><td> Precision aplicada </td><td> DeltaVision Núcleo </td><td></td></tr></tbody></table>

application of a mouse ligated peyer&#x2019;s patch intestinal loop assay to evaluate bacterial uptake by m cells

O interior do nosso intestino é habitado, com grande número de bactérias comensais. A superfície da mucosa do trato gastrointestinal é constantemente exposta a eles e, ocasionalmente, a patógenos. O tecido linfóide associado ao intestino (GALT) desempenham um papel fundamental para a indução da resposta imune da mucosa a estes micróbios 1, 2. Para iniciar a resposta imune da mucosa, os antígenos da mucosa devem ser transportados a partir da luz intestinal através da barreira epitelial em folículos linfóides organizados, tais como placas de Peyer. Este transcitose antígeno é mediada por células especializadas M epiteliais 3, 4. As células M são atípicos células epiteliais que fagocitam ativamente macromoléculas e micróbios. Ao contrário das células dendríticas (DCs) e macrófagos, antígenos que têm como alvo a lisossomos para degradação, as células M transcytose principalmente os antígenos internalizado. Este transcitose macromolecular vigorosa através de células M oferece antígeno ao subjacente organizado folículos linfóides umd acredita-se ser essencial para dar início antígeno específico da mucosa respostas imunes. No entanto, os mecanismos moleculares promover esta absorção de antígenos por células M são em grande parte desconhecido. Temos relatado anteriormente que glicoproteína 2 (GP2), especificamente expressos na membrana plasmática apical das células M entre os enterócitos, serve como um receptor transcytotic para um subconjunto de comensais e patogênicos enterobactérias, incluindo Escherichia coli e Salmonella enterica serovar Typhimurium (S. Typhimurium ), ao reconhecer FimH, um componente do tipo I pili na membrana externa bacteriana 5. Aqui, apresentamos um método para a aplicação de um ensaio de Peyer rato ciclo de patch para avaliar a absorção intestinal de bactérias pelas células M. Este método é uma versão melhorada do ensaio de loop do mouse intestinal descrito anteriormente 6, 7. Os pontos de melhoria são as seguintes: 1. Isoflurano foi usado como um agente anestésico. 2. Aproximadamente 1 cm incluindo alça ligada intestinalremendo ing Peyer foi criada. 3. Bactérias absorvidas pelas células M foram marcados por fluorescente reagente rotulagem de fluorescência ou por superexpressão da proteína fluorescente como a proteína verde fluorescente (GFP). 4. Células M no epitélio folicular associada cobrindo mancha de Peyer foram detectadas por todo o monte immunostainig com o anticorpo anti Gp2. 5. Fluorescentes transcitose bacteriana por células M foram observados por análise microscópica confocal. Corrigir o Peyer rato ensaio de alça intestinal poderia fornecer a resposta que tipo de bactérias patogênicas ou comensais transcytosed pelas células M, e pode nos levar a entender o mecanismo molecular de como estimular o sistema imunológico da mucosa através de células M.

Watch this Scientific Journal Video about Application of a Mouse Ligated Peyerâ€™s Patch Intestinal Loop Assay to Evaluate Bacterial Uptake by M cells at JoVE.com

Application of a Mouse Ligated Peyer&#8217;s Patch Intestinal Loop Assay to Evaluate Bacterial Uptake by M cells

Células M em um epitélio folículo-associados especializados que cobrem as placas de Peyer desempenhar um papel importante para a vigilância imunológica da mucosa intestinal em tecido linfóide associado. Aqui descrevemos o método de avaliação para transcitose bacteriana por células M<em&gt; In vivo</em&gt;. Este método proporciona um método para compreender a função das células M no sistema imunológico.

Aplicação de um rato ligado patch Peyer Assay alça intestinal para avaliar absorção pelas células bacterianas M

The inside of our gut is inhabited with enormous number of commensal bacteria. The mucosal surface of the gastrointestinal tract is continuously exposed ...

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Research

JoVE Journal

Immunology and Infection

Application of a Mouse Ligated Peyer&#x2019;s Patch Intestinal Loop Assay to Evaluate Bacterial Uptake by M cells

19.4K visualizações.  RIKEN Research Center for Allergy and Immunology. Células M em um epitélio folículo-associados especializados que cobrem as placas de Peyer desempenhar um papel importante para a vigilância imunológica da mucosa intestinal em tecido linfóide associado. Aqui descrevemos o método de avaliação para transcitose bacteriana por células M In vivo. Este método proporciona um método para compreender a função das células M no sistema imunológico.

Vídeo: Application of a Mouse Ligated Peyer’s Patch Intestinal Loop Assay to Evaluate Bacterial Uptake by M cells

Using Luciferase to Image Bacterial Infections in Mice

Imaging is a valuable technique that can be used to monitor biological processes. In particular, the presence of cancer cells, stem cells, specific immune cell types, viral pathogens, parasites and bacteria can be followed in real-time within living animals 1-2. Application of bioluminescence imaging to the study of pathogens has advantages as compared to conventional strategies for analysis of infections in animal models3-4. Infections can be visualized within individual animals over time, without requiring euthanasia to determine the location and quantity of the pathogen. Optical imaging allows comprehensive examination of all tissues and organs, rather than sampling of sites previously known to be infected. In addition, the accuracy of inoculation into specific tissues can be directly determined prior to carrying forward animals that were unsuccessfully inoculated throughout the entire experiment. Variability between animals can be controlled for, since imaging allows each animal to be followed individually. Imaging has the potential to greatly reduce animal numbers needed because of the ability to obtain data from numerous time points without having to sample tissues to determine pathogen load3-4.
This protocol describes methods to visualize infections in live animals using bioluminescence imaging for recombinant strains of bacteria expressing luciferase. The click beetle (CBRLuc) and firefly luciferases (FFluc) utilize luciferin as a substrate5-6. The light produced by both CBRluc and FFluc has a broad wavelength from 500 nm to 700 nm, making these luciferases excellent reporters for the optical imaging in living animal models7-9. This is primarily because wavelengths of light greater than 600 nm are required to avoid absorption by hemoglobin and, thus, travel through mammalian tissue efficiently. Luciferase is genetically introduced into the bacteria to produce light signal10. Mice are pulmonary inoculated with bioluminescent bacteria intratracheally to allow monitoring of infections in real time. After luciferin injection, images are acquired using the IVIS Imaging System. During imaging, mice are anesthetized with isoflurane using an XGI-8 Gas Anethesia System. Images can be analyzed to localize and quantify the signal source, which represents the bacterial infection site(s) and number, respectively. After imaging, CFU determination is carried out on homogenized tissue to confirm the presence of bacteria. Several doses of bacteria are used to correlate bacterial numbers with luminescence. Imaging can be applied to study of pathogenesis and evaluation of the efficacy of antibacterial compounds and vaccines.

Methods for bioluminescence imaging of bacterial infections in living animals are decribed. Pathogens are modified to express luciferase allowing optical whole body imaging of infections in live animals. Animal models can be infected with luciferase expressing pathogens and the resulting course of disease visualized in real-time by bioluminescence imaging.

Usando a luciferase Infecções bacterianas Imagem em camundongos

Imaging is a valuable technique that can be used to monitor biological processes.  In particular, the presence of cancer cells, stem cells, specific ...

Imunologia e Infecção

Invasion of Human Cells by a Bacterial Pathogen

Here we will describe how we study the invasion of human endothelial cells by bacterial pathogen Staphylococcus aureus . The general protocol can be applied to the study of cell invasion by virtually any culturable bacterium. The stages at which specific aspects of invasion can be studied, such as the role of actin rearrangement or caveolae, will be highlighted. Host cells are grown in flasks and when ready for use are seeded into 24-well plates containing Thermanox coverslips. Using coverslips allows subsequent removal of the cells from the wells to reduce interference from serum proteins deposited onto the sides of the wells (to which S. aureus would attach). Bacteria are grown to the required density and washed to remove any secreted proteins (e.g. toxins). Coverslips with confluent layers of endothelial cells are transferred to new 24-well plates containing fresh culture medium before the addition of bacteria. Bacteria and cells are then incubated together for the required amount of time in 5% CO2 at 37&deg;C. For S. aureus this is typically between 15-90 minutes. Thermanox coverslips are removed from each well and dip-washed in PBS to remove unattached bacteria. If total associated bacteria (adherent and internalised) are to be quantified, coverslips are then placed in a fresh well containing 0.5% Triton X-100 in PBS. Gentle pipetting leads to complete cell lysis and bacteria are enumerated by serial dilution and plating onto agar. If the number of bacteria that have invaded the cells is needed, coverslips are added to wells containing 500 &mu;l tissue culture medium supplemented with gentamicin and incubation continued for 1 h, which will kill all external bacteria. Coverslips can then be washed, cells lysed and bacteria enumerated by plating onto agar as described above. If the experiment requires direct visualisation, coverslips can be fixed and stained for light, fluorescence or confocal microscopy or prepared for electron microscopy.

A general protocol for the study of invasion of host cells by a bacterial pathogen, focusing on Staphylococcus aureus and human endothelial cells.

Invasão das células humanas por um agente patogénico

Here we will describe how we study the invasion of human endothelial cells by bacterial pathogen Staphylococcus aureus . The general protocol can be ...

A Visual Assay to Monitor T6SS-mediated Bacterial Competition

Type VI secretion systems (T6SSs) are molecular nanomachines allowing Gram-negative bacteria to transport and inject proteins into a wide variety of target cells1,2. The T6SS is composed of 13 core components and displays structural similarities with the tail-tube of bacteriophages3. The phage uses a tube and a puncturing device to penetrate the cell envelope of target bacteria and inject DNA. It is proposed that the T6SS is an inverted bacteriophage device creating a specific path in the bacterial cell envelope to drive effectors and toxins to the surface. The process could be taken further and the T6SS device could perforate other cells with which the bacterium is in contact, thus injecting the effectors into these targets. The tail tube and puncturing device parts of the T6SS are made with Hcp and VgrG proteins, respectively4,5.
The versatility of the T6SS has been demonstrated through studies using various bacterial pathogens. The Vibrio cholerae T6SS can remodel the cytoskeleton of eukaryotic host cells by injecting an "evolved" VgrG carrying a C-terminal actin cross-linking domain6,7. Another striking example was recently documented using Pseudomonas aeruginosa which is able to target and kill bacteria in a T6SS-dependent manner, therefore promoting the establishment of bacteria in specific microbial niches and competitive environment8,9,10.
In the latter case, three T6SS-secreted proteins, namely Tse1, Tse2 and Tse3 have been identified as the toxins injected in the target bacteria (Figure 1). The donor cell is protected from the deleterious effect of these effectors via an anti-toxin mechanism, mediated by the Tsi1, Tsi2 and Tsi3 immunity proteins8,9,10. This antimicrobial activity can be monitored when T6SS-proficient bacteria are co-cultivated on solid surfaces in competition with other bacterial species or with T6SS-inactive bacteria of the same species8,11,12,13.
The data available emphasized a numerical approach to the bacterial competition assay, including time-consuming CFU counting that depends greatly on antibiotic makers. In the case of antibiotic resistant strains like P. aeruginosa, these methods can be inappropriate. Moreover, with the identification of about 200 different T6SS loci in more than 100 bacterial genomes14, a convenient screening tool is highly desirable. We developed an assay that is easy to use and requires standard laboratory material and reagents. The method offers a rapid and qualitative technique to monitor the T6SS-dependent bactericidal/bacteriostasis activity by using a reporter strain as a prey (in this case Escherichia coli DH5&alpha;) allowing a-complementation of the lacZ gene. Overall, this method is graphic and allows rapid identification of T6SS-related phenotypes on agar plates. This experimental protocol may be adapted to other strains or bacterial species taking into account specific conditions such as growth media, temperature or time of contact.

We describe a qualitative assay to monitor bacterial competition mediated by the Pseudomonas aeruginosa type VI secretion system (T6SS). The assay relies on the survival/killing of Escherichia coli target cells carrying a lacZ-reporter. This technique is adjustable to assess the bactericidal/bacteriostasis activity of T6SS-proficient microorganisms.

Um Ensaio visual para o Monitor T6SS mediada Competição bacteriana

Type VI secretion systems (T6SSs) are molecular  nanomachines allowing Gram-negative bacteria to transport and inject proteins  into a wide variety of ...

The Mesenteric Lymph Duct Cannulated Rat Model: Application to the Assessment of Intestinal Lymphatic Drug Transport

The intestinal lymphatic system plays key roles in fluid transport, lipid absorption and immune function. Lymph flows directly from the small intestine via a series of lymphatic vessels and nodes that converge at the superior mesenteric lymph duct. Cannulation of the mesenteric lymph duct thus enables the collection of mesenteric lymph flowing from the intestine. Mesenteric lymph consists of a cellular fraction of immune cells (99% lymphocytes), aqueous fraction (fluid, peptides and proteins such as cytokines and gut hormones) and lipoprotein fraction (lipids, lipophilic molecules and apo-proteins). The mesenteric lymph duct cannulation model can therefore be used to measure the concentration and rate of transport of a range of factors from the intestine via the lymphatic system. Changes to these factors in response to different challenges (e.g., diets, antigens, drugs) and in disease (e.g., inflammatory bowel disease, HIV, diabetes) can also be determined. An area of expanding interest is the role of lymphatic transport in the absorption of orally administered lipophilic drugs and prodrugs that associate with intestinal lipid absorption pathways. Here we describe, in detail, a mesenteric lymph duct cannulated rat model which enables evaluation of the rate and extent of lipid and drug transport via the lymphatic system for several hours following intestinal delivery. The method is easily adaptable to the measurement of other parameters in lymph. We provide detailed descriptions of the difficulties that may be encountered when establishing this complex surgical method, as well as representative data from failed and successful experiments to provide instruction on how to confirm experimental success and interpret the data obtained.

Here we describe a technique to cannulate the mesenteric lymph duct in rats which enables quantification of lipid and drug transport via the lymphatic system following intestinal delivery. The technique can be adapted to assess mesenteric lymph concentrations and/or transport of fluid, immune cells, peptides, proteins and lipophilic molecules.

A linfa mesentérica Duct canulada Rat Modelo: Aplicação para a Avaliação de Intestinal Linfática transporte da droga

The intestinal lymphatic system plays key roles in fluid transport, lipid absorption and immune function. Lymph flows directly from the small intestine ...

Application of Long-term cultured Interferon-&#947; Enzyme-linked Immunospot Assay for Assessing Effector and Memory T Cell Responses in Cattle

Effector and memory T cells are generated through developmental programing of na&#239;ve cells following antigen recognition. If the infection is controlled up to 95 % of the T cells generated during the expansion phase are eliminated (i.e., contraction phase) and memory T cells remain, sometimes for a lifetime. In humans, two functionally distinct subsets of memory T cells have been described based on the expression of lymph node homing receptors. Central memory T cells express C-C chemokine receptor 7 and CD45RO and are mainly located in T-cell areas of secondary lymphoid organs. Effector memory T cells express CD45RO, lack CCR7 and display receptors associated with lymphocyte homing to peripheral or inflamed tissues. Effector T cells do not express either CCR7 or CD45RO but upon encounter with antigen produce effector cytokines, such as interferon-&#947;. Interferon-&#947; release assays are used for the diagnosis of bovine and human tuberculosis and detect primarily effector and effector memory T cell responses. Central memory T cell responses by CD4+ T cells to vaccination, on the other hand, may be used to predict vaccine efficacy, as demonstrated with simian immunodeficiency virus infection of non-human primates, tuberculosis in mice, and malaria in humans. Several studies with mice and humans as well as unpublished data on cattle, have demonstrated that interferon-&#947; ELISPOT assays measure central memory T cell responses. With this assay, peripheral blood mononuclear cells are cultured in decreasing concentration of antigen for 10 to 14 days (long-term culture), allowing effector responses to peak and wane; facilitating central memory T cells to differentiate and expand within the culture.

Long-term cultured interferon-&#947; enzyme-linked immunospot assay is used as a measure of central memory responses and correlates with protective anti-mycobacterial vaccine responses. With this assay, peripheral blood mononuclear cells are stimulated with mycobacterial antigens and interleukin-2 for 14 days, enabling differentiation and expansion of central memory T cells.

Aplicação de longo prazo cultivadas Interferon-γ Enzyme-linked Immunospot Ensaio para a Avaliação e efetoras de memória T respostas de células em gado

Effector and memory T cells are generated through developmental programing of na&#239;ve cells following antigen recognition. If the infection is ...

Detecting Cortex Fragments During Bacterial Spore Germination

The process of endospore germination in Clostridium difficile, and other Clostridia, increasingly is being found to differ from the model spore-forming bacterium, Bacillus subtilis. Germination is triggered by small molecule germinants and occurs without the need for macromolecular synthesis. Though differences exist between the mechanisms of spore germination in species of Bacillus and Clostridium, a common requirement is the hydrolysis of the peptidoglycan-like cortex which allows the spore core to swell and rehydrate. After rehydration, metabolism can begin and this, eventually, leads to outgrowth of a vegetative cell. The detection of hydrolyzed cortex fragments during spore germination can be difficult and the modifications to the previously described assays can be confusing or difficult to reproduce. Thus, based on our recent report using this assay, we detail a step-by-step protocol for the colorimetric detection of cortex fragments during bacterial spore germination.

Herein, we describe a colorimetric assay to detect the presence of reducing sugars during bacterial spore germination.

Detecção de Cortex Fragmentos Durante bacteriana germinação de esporos

The process of endospore germination in Clostridium difficile, and other Clostridia, increasingly is being found to differ from the model spore-forming ...

Use of a Monocyte Monolayer Assay to Evaluate Fc&#947; Receptor-mediated Phagocytosis

Although originally developed for predicting transfusion outcomes of serologically incompatible blood, the monocyte monolayer assay (MMA) is a highly versatile in vitro assay that can be modified to examine different aspects of antibody and Fc&#947; receptor (Fc&#947;R)-mediated phagocytosis in both research and clinical settings. The assay utilizes adherent monocytes from peripheral blood mononuclear cells isolated from mammalian whole blood. MMA has been described for use in both human and murine investigations. These monocytes express Fc&#947;Rs (e.g., Fc&#947;RI, Fc&#947;RIIA, Fc&#947;RIIB, and Fc&#947;RIIIA) that are involved in immune responses. The MMA exploits the mechanism of Fc&#947;R-mediated interactions, phagocytosis in particular, where antibody-sensitized red blood cells (RBCs) adhere to and/or activate Fc&#947;Rs and are subsequently phagocytosed by the monocytes. In vivo, primarily tissue macrophages found in the spleen and liver carry out Fc&#947;R-mediated phagocytosis of antibody-opsonized RBCs, causing extravascular hemolysis. By evaluating the level of phagocytosis using the MMA, different aspects of the in vivo Fc&#947;R-mediated process can be investigated. Some applications of the MMA include predicting the clinical relevance of allo- or autoantibodies in a transfusion setting, assessing candidate drugs that promote or inhibit phagocytosis, and combining the assay with fluorescent microscopy or traditional Western immunoblotting to investigate the downstream signaling effects of Fc&#947;R-engaging drugs or antibodies. Some limitations include the laboriousness of this technique, which takes a full day from start to finish, and the requirement of research ethics approval in order to work with mammalian blood. However, with diligence and adequate training, the MMA results can be obtained within a 24-h turnover time.

The monocyte monolayer assay (MMA) is an in vitro assay that utilizes isolated primary monocytes obtained from mammalian peripheral whole blood to evaluate Fc&#947; receptor (Fc&#947;R)-mediated phagocytosis.

Uso de um monócito monocamada Ensaio para Avaliar a fagocitose mediada pelo receptor Fcy

Although originally developed for predicting transfusion outcomes of serologically incompatible blood, the monocyte monolayer assay (MMA) is a highly ...

Immunofluorescence Analysis of Stress Granule Formation After Bacterial Challenge of Mammalian Cells

Fluorescent imaging of cellular components is an effective tool to investigate host-pathogen interactions. Pathogens can affect many different features of infected cells, including organelle ultrastructure, cytoskeletal network organization, as well as cellular processes such as Stress Granule (SG) formation. The characterization of how pathogens subvert host processes is an important and integral part of the field of pathogenesis. While variable phenotypes may be readily visible, the precise analysis of the qualitative and quantitative differences in the cellular structures induced by pathogen challenge is essential for defining statistically significant differences between experimental and control samples. SG formation is an evolutionarily conserved stress response that leads to antiviral responses and has long been investigated using viral infections1. SG formation also affects signaling cascades and may have other still unknown consequences2. The characterization of this stress response to pathogens other than viruses, such as bacterial pathogens, is currently an emerging area of research3. For now, quantitative and qualitative analysis of SG formation is not yet routinely used, even in the viral systems. Here we describe a simple method for inducing and characterizing SG formation in uninfected cells and in cells infected with a cytosolic bacterial pathogen, which affects the formation of SGs in response to various exogenous stresses. Analysis of SG formation and composition is achieved by using a number of different SG markers and the spot detector plug-in of ICY, an open source image analysis tool.

We describe a method for the qualitative and quantitative analysis of stress granule formation in mammalian cells after the cells are challenged with bacteria and a number of different stresses. This protocol can be applied to investigate the cellular stress granule response in a wide range of host-bacterial interactions.

Análise de imunofluorescência da formação de grânulos de estresse após o desafio bacteriano de células de mamífero

Fluorescent imaging of cellular components is an effective tool to investigate host-pathogen interactions. Pathogens can affect many different features of ...

A Novel In Vitro Wound Healing Assay to Evaluate Cell Migration

The aim of this work is to show a novel method to evaluate the ability of some immunomodulatory molecules, such as antimicrobial peptides (AMPs), to stimulate cell migration. Importantly, cell migration is a rate-limiting event during the wound-healing process to re-establish the integrity and normal function of tissue layers after injury. The advantage of this method over the classical assay, which is based on a manually made scratch in a cell monolayer, is the usage of special silicone culture inserts providing two compartments to create a cell-free pseudo-wound field with a well-defined width (500 &#956;m). In addition, due to an automated image analysis platform, it is possible to rapidly obtain quantitative data on the speed of wound closure and cell migration. More precisely, the effect of two frog-skin AMPs on the migration of bronchial epithelial cells will be shown. Furthermore, pretreatment of these cells with specific inhibitors will provide information on the molecular mechanisms underlying such events.

A Novel In Vitro Wound Healing Assay to Evaluate Cell Migration

Here, we present a protocol to evaluate the effect of peptides on the migration of bronchial epithelial cells. This method allows for the rapid and highly reproducible obtainment of quantitative data on the speed of cell migration and wound closure.

Um romance em Vitro ferida cura ensaio para avaliar a migração celular

The aim of this work is to show a novel method to evaluate the ability of some immunomodulatory molecules, such as antimicrobial peptides (AMPs), to ...

Cell Membrane Repair Assay Using a Two-photon Laser Microscope

Numerous pathophysiological insults can cause damage to cell membranes and, when coupled with innate defects in cell membrane repair or integrity, can result in disease. Understanding the underlying molecular mechanisms surrounding cell membrane repair is, therefore, an important objective to the development of novel therapeutic strategies for diseases associated with dysfunctional cell membrane dynamics. Many in vitro and in vivo studies aimed at understanding cell membrane resealing in various disease contexts utilize two-photon laser ablation as a standard for determining functional outcomes following experimental treatments. In this assay, cell membranes are subjected to wounding with a two-photon laser, which causes the cell membrane to rupture and fluorescent dye to infiltrate the cell. The intensity of fluorescence within the cell can then be monitored to quantify the cell's ability to reseal itself. There are several alternative methods for assessing cell membrane response to injury, as well as great variation in the two-photon laser wounding approach itself, therefore, a single, unified model of cell wounding would beneficially serve to decrease the variation between these methodologies. In this article, we outline a simple two-photon laser wounding protocol for assessing cell membrane repair in vitro in both healthy and dysferlinopathy patient fibroblast cells transfected with or without a full-length dysferlin plasmid.

Cell membrane wounding via two-photon laser is a widely used method for assessing membrane resealing ability and can be applied to multiple cell types. Here, we describe a protocol for in vitro live-imaging of membrane resealing in dysferlinopathy patient cells following two-photon laser ablation.

Ensaio de reparação da membrana celular usando um microscópio de dois fotões Laser

Numerous pathophysiological insults can cause damage to cell membranes and, when coupled with innate defects in cell membrane repair or integrity, can ...