1. A inoculação do vírus e purificação de VLPs Plantas de Nicotiana benthamiana <ol><li> Produzir seladas T7-RNA transcritos a partir de Potato virus X (PVX) baseados em plasmídeos vector transportando MRFV de tipo selvagem (wt) e da proteína de revestimento Cys-mutada (CP) genes 12, utilizando T7-mMessage Ambion de mMachine Kit. </li><li> Para cada reacção de transcrição de T7, inocular duas folhas completamente expandidas de N. benthamiana com 10 ul de reacções e incuba-se as plantas durante 10 dias em estufa, a uma humidade de 60% ​​durante 16 h com luz (25.000-30.000 lux) a 25 ° C e 8 horas escuro a 20 ° C. </li><li> Harves t N. benthamiana infectadas por vírus folhas 10 dias após a inoculação (dpi), pesar o tecido vegetal (50 gramas) e colocar em gelo. </li><li> Homogeneizar o material de planta em um misturador em presença de 100 ml de uma solução gelada de 0,5 M de tampão de Na-citrato, pH 5,5 (o uso de 2 ml de tampão por grama de tecido de planta). </li><li> Filtrar homogenato através de 3 camadas de cheeseclOTH e clarificar através de centrifugação a 27.000 xg durante 30 min. Transferir o sobrenadante em um cilindro refrigerado graduada, medir o volume, e depois transferir para um copo gelado estéril. Descartar o sedimento. </li><li> Processar-se o sobrenadante por adição de polietileno glicol 8000 a 10% (PEG 8000), agita-se durante 15 min a 4 ° C, e incubar durante mais 45 minutos a 4 ° C para precipitar as partículas semelhantes a vírus (VLPs) de PEG-matriz. </li><li> Centrifugar a amostra a 27.000 xg durante 20 min a 4 ° C e remove-se o sobrenadante. </li><li> Processar o sedimento, adicionando 8 ml de 0,05 M de tampão de Na-citrato, pH 5,5, contendo 2% de Triton X-100. Redemoinho tubos da centrífuga bem para liberar o sedimento. Transferir o sedimento e tampão para um copo de gelado estéril. Enxaguar imediatamente os tubos com 2 ml do mesmo tampão e adicionar ao copo. Agita-se a suspensão a 4 ° C até que os grânulos são dissolvidos (em geral 1 hora). </li><li> Clarificar por centrifugação durante 5 min a 27.000 xg, rejeitar o sedimento, e process o sobrenadante por centrifugação a 140000 xg durante 2 horas a 4 ° C. </li><li> Ressuspender o sedimento em 1 ml de tampão de 0,05 M de Na-citrato, pH 5,5 e colocar a suspensão no topo de um gradiente de sacarose 10-40% feita em 0,05 M de tampão de Na-citrato, pH 5,5. </li><li> Centrifuga-se o gradiente durante 3 horas a 140.000 xg a 4 ° C. </li><li> Brilhar uma luz sobre o topo do tubo da centrífuga e recolher a banda de dispersão da luz superior a 4 cm a partir do topo do tubo, diluiu-se com 0,05 M de tampão de Na-citrato, pH 5.5, e centrifuga-se durante 3 horas a 140.000 xg a 4 ° C. </li><li> Ressuspender o sedimento em 0,5 ml de água estéril e armazenar a 4 ° C durante até seis meses. </li><li> Quantificar a concentração de VLPs por realização de um ensaio de proteína de Bradford. O rendimento de VLPs está entre 1 e 3 ng / g de tecido da planta. </li></ol> 2. Fluoresceína-5-maleimida rotulagem Reações de VLP <ol><li> Prepara-se uma solução 1 mM de f luoresceina-5-maleimida (427,37 g / mole) em 50 mM de sódio phosphate tampão, pH 7,0, 1 mM de EDTA. Misturar utilizando o vórtice e verificar dissolução completa. Proteger o tubo de luz, utilizando uma folha de alumínio. </li><li> Adicionar fluoresceína-5-maleimida de VLPs produzidas no passo 1 e misturar. Usar um excesso de 25 vezes molar de f luoresceina-5-maleimida para a quantidade molar de sulfidrilos. Geralmente, utilizar-se 30 ul de partículas VLP, na concentração de 1 ug / ul e 60 ul da solução de fluoresceína-5-maleimida produz resultados aceitáveis. </li><li> Incubar a mistura reaccional durante 2 horas à temperatura ambiente ou durante a noite a 4 ° C. </li><li> Terminar a reacção por adição de ditiotreitol (DTT) até uma concentração final de 50 mM. </li><li> Remover não reagidos fluoresceína, utilizando uma coluna de spin de dessalinização (Thermo Scientific Inc, Rockford IL) e centrifugação durante 2 minutos a 1500 xg à temperatura ambiente. </li><li> Por análise de SDS-PAGE, adicionam-se 10 ul de 2 x tampão de amostra de SDS-PAGE de Laemmli a 10 ul de cada reacção. Armazenar a proteína marcada ao abrigo da luz a 4 ° C, durante até um mês oude utilização única em alíquotas a -20 ° C até 3 meses. </li></ol> 3. Reação rotulagem e determinação de Incorporação Biotina <ol><li> Use colunas de centrifugação de dessalinização (Thermo Scientific Inc., Rockford IL) para realizar uma permuta de tampão de água a uma solução de tampão fosfato salino (PBS), pH 7,0 as VLPs produzidas no passo 1. </li><li> Prepare uma solução de 20 mM de maleimida-PEG2-biotina, adicionando 190 ul de PBS em No-Pesar maleimida PEG2-biotina e misture pipetando para cima e para baixo. </li><li> Adicionar maleimida-PEG2-biotina para as VLPs e misturar. Usar um excesso molar de 10 vezes de reagente de VLPs soluções ≤ 2 mg / ml. </li><li> Incubar a mistura reaccional à temperatura ambiente durante 4 horas. </li><li> Remover não reagidos maleimida-PEG2-biotina, utilizando uma coluna de dessalinização de spin (Thermo Scientific Inc, Rockford IL) e centrifugação durante 2 minutos a 1500 xg à temperatura ambiente. </li><li> Determinar as moles de biotina por moles de VLPs utilizando o Kit Pierce Quantitation Biotina (Thermo Scientific) e following instruções do fabricante. </li></ol> 4. A ligação cruzada de 2-Cys e VLPs Peptide F <ol><li> VLPs que resultou em resíduos de cisteína disponível para a ligação cruzada no passo 2 (2-Cys VLPs) são utilizados no passo seguinte. Preparar uma solução-mãe fresca de reticulação (28,63 mM) por dissolução de 10 mg de agente de reticulação-NHS-PEG4-maleimida em 680 uL de sulfóxido de dimetilo. </li><li> Dissolver a 17 (F)-amino ácido do péptido longo (LLPNMOKDKEACAKAPL) em 50 ul de tampão de conjugação (1 x PBS, pH 7,2, 1 mM de EDTA) a uma concentração de 0,1 mM. </li><li> Adicionar 4 ul de agente de reticulação de 50 ul de péptido dissolvido (proteína-NH2) a uma concentração de mM final (que é um excesso molar de 10 vezes para 0,1 mM de solução de péptido). </li><li> Incubar a mistura reaccional durante 2 horas a 4 ° C. </li><li> Purificar reticulado péptido utilizando uma coluna de dessalinização (Thermo Scientific Inc., Rockford IL) equilibrada com tampão de conjugação (1 x PBS, pH 7,2, 1 mM EDTA) por centrifugação a 1500 xg, durante 1 minuto à temperatura ambiente. </li><li> Defina-se a mistura de reacção combinando VLPs (proteína-SH) e de ligação cruzada de péptidos (proteína-NH2), em uma proporção molar determinada pelo número de aminas e tióis activados envolvidos na reacção e a diferença de peso molecular entre VLPs e peptídicas. </li><li> Incubar a mistura de reacção à temperatura ambiente durante 2 horas a 4 ° C. </li><li> Para a análise de Western blot, misturar o produto resultante conjugado de 1:1 com tampão Laemmli, deixar ferver por 10 minutos, e continuar com SDS-PAGE num molde pré-10-20% de Tris-Glicina gel (Invitrogen), seguido de electrotransferência para uma membrana de nitrocelulose (Invitrogen). Bloquear as membranas com 1 x PBS, pH 7,2, contendo 0,05% de Tween-20 (PBS-Tween) e leite em pó desnatado a 5% e com sonda de anticorpos específicos do péptido, seguido pelo anticorpo marcado com fosfatase secundário apropriado. </li></ol>

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O método aqui apresentado permite uma análise muito sensível e rápida de cisteínas reactivos presentes na superfície das plantas produzidas VLPs, bem como em outros complexos de proteínas. As maleimidas são específicas de reagentes de tiol, que reagem com o grupo sulfidrilo livre que contêm moléculas de modo a formar ligações tioéter estáveis. Este método baseia-se na especificidade das maleimidas para reagir com grupos sulfidrilo que não estão envolvidos em interacções com outros aminoácidos. A pre...

<table border="1"><tbody><tr><td> Nome do reagente </td><td> Companhia </td><td> Número de catálogo </td><td> Comentários </td></tr><tr><td> Thinwall, Ultra-Clear Tubos </td><td> Beckman </td><td> 344059 </td><td></td></tr><tr><td> mMESSAGE mMACHINE T7 Kit </td><td> Tecnologias de vida </td><td> AM1344M </td><td></td></tr><tr><td> F luoresceina-5-maleimida </td><td> Vida Thermo Scientific Technologies </td><td> 46130 F150 </td><td> 46130 está fora de ordem com substituto F150 </td></tr><tr><td> Pierce Kit quantificação Biotina </td><td> Thermo Scientific </td><td> 28005 </td><td></td></tr><tr><td> EZ-Link Maleimida PEG2-Biotina, No-Pesar Formato </td><td> Thermo Scientific </td><td> 21901 </td><td></td></tr><tr><td> SM (PEG) n Reticuladores </td><td> Thermo Scientific </td><td> 22107 </td><td></td></tr><tr><td> 10-20% de Tris-Glicina gel </td><td> Invitrogen </td><td> EC61352 </td><td></td></tr><tr><td> Tampão de Laemmli </td><td> Bio-Rad </td><td> 1610737 </td><td></td></tr><tr><td> Tris Glycine SDS tampão de corrida </td><td> Invitrogen </td><td> LC2675 </td><td></td></tr><tr><td> Tris Glycine Transferência de buffer </td><td> Invitrogen </td><td> LC3675 </td><td></td></tr><tr><td> Membrana de nitrocelulose Sandwich papel de filtro </td><td> Invitrogen </td><td> LC2001 </td><td></td></tr><tr><td> Afinidade fosfatase Labeled anticorpo purificado a IgG de coelho </td><td> Kirkegaard and Perry Laboratories </td><td> 0751516 </td><td></td></tr><tr><td> NBT / BCIP de substrato de fosfatase </td><td> Kirkegaard and Perry Laboratories </td><td> 508107 </td><td></td></tr></tbody></table>

analysis of the solvent accessibility of cysteine residues on maize rayado fino virus virus-like particles produced in nicotiana benthamiana plants and cross-linking of peptides to vlps

Imitando e explorar as propriedades e características físico-químicas, vírus e física tem a promessa de fornecer soluções para alguns dos desafios mais prementes do mundo. A variedade e tipos de vírus, juntamente com suas propriedades intrigantes, potencialmente, dar oportunidades infinitas para aplicações em tecnologias baseadas em vírus. Vírus têm a capacidade de se auto-organizar em partículas com forma e tamanho discreto, a especificidade de simetria, polivalência e propriedades estáveis ​​sob uma variedade de condições de temperatura e pH. Não surpreendentemente, com uma gama tão extraordinária de propriedades, os vírus são propostas para uso em biomateriais 9, 14, 15 vacinas, materiais eletrônicos, ferramentas químicas e molecular recipientes eletrônico 4, 5, 10, 11, 16, 18, ​​12. A fim de utilizar os vírus em nanotecnologia, eles devem ser modificados a partir de suas formas naturais para conferir novas funções. Este pr desafiadorocesso pode ser realizada através de vários mecanismos, incluindo a modificação genética do genoma virai e a fixação de moléculas quimicamente estrangeiras ou desejado para as partículas de vírus grupos reactivos 8. A capacidade de modificar vírus principalmente depende das propriedades físico-químicas e físicas do vírus. Além disso, as modificações genéticas ou físico-química precisam ser executadas sem afectar adversamente a estrutura do vírus nativo e função do vírus. Maize rayado fino vírus proteínas (MRFV) revestimento auto-montar em Escherichia coli produtoras de VLPs estáveis ​​e vazios que são estabilizadas por proteína-proteína interações e que pode ser usado em aplicações baseadas em tecnologias vírus 8. VLPs produzidas em plantas de tabaco foram examinados como um andaime sobre o qual uma grande variedade de péptidos pode ser covalentemente exibida 13. Aqui, descrevem-se as etapas de: 1) determinar quais as cisteínas solventes acessíveis em um capsídeo do vírus estão disponíveis para modificaçãocação, e 2) Bioconjugate péptidos aos capsídios modificados. Usando nativas ou mutationally-inserido resíduos de aminoácidos e as tecnologias de acoplamento normalizados, uma grande variedade de materiais tem sido apresentados na superfície de vírus de plantas, tais como, o vírus do mosaico Brome 3, vírus Carnation mottle 12, Cowpea cloróticas mottle virus 6, do mosaico do tabaco 17 vírus, o vírus do mosaico do nabo amarelo 1, e MRFV 13.

Expressão transitória de mutantes casaco MRFV proteína (PB) genes em N. benthamiana plantas em um PVX VLPs baseadas em vetor produção está descrito na Figura 1. A modificação MRFV gene da proteína da cápside é amplificado por PCR e, em seguida, colocado sob o controlo transcricional do promotor duplicado subgenómico CP num vector baseado PVX, pP2C2S 2, (uma oferta de D. Baulcombe, Sainsbury Laboratories, Norwich, Inglaterra). Na transcrição de ARN in vitro<...

Watch this Scientific Journal Video about Analysis of the Solvent Accessibility of Cysteine Residues on Maize rayado fino virus Virus-like Particles Produced in Nicotiana benthamiana Plants and Cross-

Analysis of the Solvent Accessibility of Cysteine Residues on Maize rayado fino virus Virus-like Particles Produced in Nicotiana benthamiana Plants and Cross-linking of Peptides to VLPs

Um método para analisar a acessibilidade do solvente do grupo tiol de resíduos de cisteína de<em&gt; Milho rayado fino vírus</em&gt; (MRFV)-partículas semelhantes a vírus (VLPs), seguido por uma reacção de ligação cruzada de péptidos é descrito. O método tira partido da existência de grupos químicos sobre a superfície das partículas VLP, que podem ser alvos para as reacções específicas.

Análise da acessibilidade de solvente de resíduos de cisteína em<em&gt; Milho rayado fino vírus</em&gt; Partículas semelhantes a vírus produzidas em<em&gt; Nicotiana benthamiana</em&gt; Plantas e cross-linking de peptídeos para VLP

Mimicking  and exploiting virus properties and physicochemical and physical  characteristics holds promise to provide solutions to some of  the world's ...

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Immunology and Infection

Analysis of the Solvent Accessibility of Cysteine Residues on Maize rayado fino virus Virus-like Particles Produced in Nicotiana benthamiana Plants and Cross-linking of Peptides to VLPs

11.0K visualizações.  Agricultural Research Service, United States Department of Agriculture. Um método para analisar a acessibilidade do solvente do grupo tiol de resíduos de cisteína de Milho rayado fino vírus (MRFV)-partículas semelhantes a vírus (VLPs), seguido por uma reacção de ligação cruzada de péptidos é descrito. O método tira partido da existência de grupos químicos sobre a superfície das partículas VLP, que podem ser alvos para as reacções específicas.

Vídeo: Analysis of the Solvent Accessibility of Cysteine Residues on Maize rayado fino virus Virus-like Particles Produced in Nicotiana benthamiana Plants and Cross-linking of Peptides to VLPs

Isolation and Genome Analysis of Single Virions using 'Single Virus Genomics'

Whole genome amplification and sequencing of single microbial cells enables genomic characterization without the need of cultivation 1-3. Viruses, which are ubiquitous and the most numerous entities on our planet 4 and important in all environments 5, have yet to be revealed via similar approaches. Here we describe an approach for isolating and characterizing the genomes of single virions called 'Single Virus Genomics' (SVG). SVG utilizes flow cytometry to isolate individual viruses and whole genome amplification to obtain high molecular weight genomic DNA (gDNA) that can be used in subsequent sequencing reactions.

Isolation and Genome Analysis of Single Virions using &#039;Single Virus Genomics&#039;

Single Virus Genomics (SVG) is a method to isolate and amplify the genomes of single virons. Viral suspensions of a mixed assemblage are sorted using flow cytometry onto a microscope slide with discrete wells containing agarose, thereby capturing the virion and reducing genome shearing during downstream processing. Whole genome amplification is achieved using multiple displacement amplification (MDA) resulting in genomic material that is suitable for sequencing.

Isolamento e Análise do Genoma do vírus da única usando &#39;Genomics vírus simples&#39;

Whole genome amplification and sequencing of single microbial cells enables genomic characterization without the need of cultivation 1-3. Viruses, which ...

Imunologia e Infecção

Analysis of the Epithelial Damage Produced by Entamoeba histolytica Infection

Entamoeba histolytica is the causative agent of human amoebiasis, a major cause of diarrhea and hepatic abscess in tropical countries. Infection is initiated by interaction of the pathogen with intestinal epithelial cells. This interaction leads to disruption of intercellular structures such as tight junctions (TJ). TJ ensure sealing of the epithelial layer to separate host tissue from gut lumen. Recent studies provide evidence that disruption of TJ by the parasitic protein EhCPADH112 is a prerequisite for E. histolytica invasion that is accompanied by epithelial barrier dysfunction. Thus, the analysis of molecular mechanisms involved in TJ disassembly during E. histolytica invasion is of paramount importance to improve our understanding of amoebiasis pathogenesis. This article presents an easy model that allows the assessment of initial host-pathogen interactions and the parasite invasion potential. Parameters to be analyzed include transepithelial electrical resistance, interaction of EhCPADH112 with epithelial surface receptors, changes in expression and localization of epithelial junctional markers and localization of parasite molecules within epithelial cells.

Analysis of the Epithelial Damage Produced by Entamoeba histolytica Infection

Human infection by Entamoeba histolytica leads to amoebiasis, a major cause of diarrhea in tropical countries. Infection is initiated by pathogen interactions with intestinal epithelial cells, provoking the opening of cell-cell contacts and consequently diarrhea, sometimes followed by liver infection. This article provides a model to assess the early host-pathogen interactions to improve our understanding of amoebiasis pathogenesis.

Análise do dano epitelial Produzido pela<em&gt; Entamoeba histolytica</em&gt; Infecção

Entamoeba histolytica is the causative agent of human amoebiasis, a major cause of diarrhea and hepatic abscess in tropical countries. Infection is ...

In Vitro Analysis of Myd88-mediated Cellular Immune Response to West Nile Virus Mutant Strain Infection

An attenuated West Nile virus (WNV), a nonstructural (NS) 4B-P38G mutant, induced higher innate cytokine and T cell responses than the wild-type WNV in mice. Recently, myeloid differentiation factor 88 (MyD88) signaling was shown to be important for initial T cell priming and memory T cell development during WNV NS4B-P38G mutant infection. In this study, two flow cytometry-based methods &#8211; an in vitro T cell priming assay and an intracellular cytokine staining (ICS) &#8211; were utilized to assess dendritic cells (DCs) and T cell functions. In the T cell priming assay, cell proliferation was analyzed by flow cytometry following co-culture of DCs from both groups of mice with carboxyfluorescein succinimidyl ester (CFSE) - labeled CD4+ T cells of OTII transgenic mice. This approach provided an accurate determination of the percentage of proliferating CD4+ T cells with significantly improved overall sensitivity than the traditional assays with radioactive reagents. A microcentrifuge tube system was used in both cell culture and cytokine staining procedures of the ICS protocol. Compared to the traditional tissue culture plate-based system, this modified procedure was easier to perform at biosafety level (BL) 3 facilities. Moreover, WNV- infected cells were treated with paraformaldehyde in both assays, which enabled further analysis outside BL3 facilities. Overall, these in vitro immunological assays can be used to efficiently assess cell-mediated immune responses during WNV infection.

In Vitro Analysis of Myd88-mediated Cellular Immune Response to West Nile Virus Mutant Strain Infection

Two flow cytometry-based methods &#8211; an in vitro T cell priming assay and intracellular cytokine staining were utilized to measure antigen presenting capacity of dendritic cells and antigen-specific T cell responses to a West Nile virus mutant infection in mice.

In Vitro Análise do mediada por Myd88 Cellular resposta imune a vírus do Nilo Ocidental Mutant Strain Infection

An attenuated West Nile virus (WNV), a nonstructural (NS) 4B-P38G mutant, induced higher innate cytokine and T cell responses than the wild-type WNV in ...

Modeling The Lifecycle Of Ebola Virus Under Biosafety Level 2 Conditions With Virus-like Particles Containing Tetracistronic Minigenomes

Ebola viruses cause severe hemorrhagic fevers in humans and non-human primates, with case fatality rates as high as 90%. There are no approved vaccines or specific treatments for the disease caused by these viruses, and work with infectious Ebola viruses is restricted to biosafety level 4 laboratories, significantly limiting the research on these viruses. Lifecycle modeling systems model the virus lifecycle under biosafety level 2 conditions; however, until recently such systems have been limited to either individual aspects of the virus lifecycle, or a single infectious cycle. Tetracistronic minigenomes, which consist of Ebola virus non-coding regions, a reporter gene, and three Ebola virus genes involved in morphogenesis, budding, and entry (VP40, GP1,2, and VP24), can be used to produce replication and transcription-competent virus-like particles (trVLPs) containing these minigenomes. These trVLPs can continuously infect cells expressing the Ebola virus proteins responsible for genome replication and transcription, allowing us to safely model multiple infectious cycles under biosafety level 2 conditions. Importantly, the viral components of this systems are solely derived from Ebola virus and not from other viruses (as is, for example, the case in systems using pseudotyped viruses), and VP40, GP1,2 and VP24 are not overexpressed in this system, making it ideally suited for studying morphogenesis, budding and entry, although other aspects of the virus lifecycle such as genome replication and transcription can also be modeled with this system. Therefore, the tetracistronic trVLP assay represents the most comprehensive lifecycle modeling system available for Ebola viruses, and has tremendous potential for use in investigating the biology of Ebola viruses in future. Here, we provide detailed information on the use of this system, as well as on expected results.

Work with infectious Ebola viruses is restricted to biosafety level 4 laboratories. Tetracistronic minigenome-containing replication and transcription-competent virus like particles (trVLPs) represent a lifecycle modeling system that allows us to safely model multiple infectious cycles under biosafety level 2 conditions, relying exclusively on Ebola virus components.

Modelando o ciclo de vida do vírus Ebola Sob Nível de Biossegurança 2 condições com partículas semelhantes a vírus contendo Tetracistronic minigenomas

Ebola viruses cause severe hemorrhagic fevers in humans and non-human primates, with case fatality rates as high as 90%. There are no approved vaccines or ...

Neutrophil Isolation and Analysis to Determine their Role in Lymphoma Cell Sensitivity to Therapeutic Agents

Neutrophils are the most abundant (40% to 75%) type of white blood cells and among the first inflammatory cells to migrate towards the site of inflammation. They are key players in the innate immune system and play major roles in cancer biology. Neutrophils have been proposed as key mediators of malignant transformation, tumor progression, angiogenesis and in the modulation of the antitumor immunity; through their release of soluble factors or their interaction with tumor cells. To characterize the specific functions of neutrophils, a fast and reliable method is coveted for in vitro isolation of neutrophils from human blood. Here, a density gradient separation method is demonstrated to isolate neutrophils as well as mononuclear cells from the blood. The procedure consists of layering the density gradient solution such as Ficoll carefully above the diluted blood obtained from patients diagnosed with chronic lymphocytic leukemia (CLL), followed by centrifugation, isolation of mononuclear layer, separation of neutrophils from RBCsby dextran then lysis of residual erythrocytes. This method has been shown to isolate neutrophils &#8805; 90 % pure. To mimic the tumor microenvironment, 3-dimensional (3D) experiments were performed using basement membrane matrix such as Matrigel. Given the short half-life of neutrophils in vitro, 3D experiments with fresh human neutrophils cannot be performed. For this reason promyelocytic HL60 cells are differentiated along the granulocytic pathway using the differentiation inducers dimethyl sulfoxide (DMSO) and retinoic acid (RA). The aim of our experiments is to study the role of neutrophils on the sensitivity of lymphoma cells to anti-lymphoma agents. However these methods can be generalized to study the interactions of neutrophils or neutrophil-like cells with a large range of cell types in different situations.

Neutrophils are the most abundant type of white blood cells. The isolation of neutrophils from human blood by density gradient separation method and the differentiation of human promyelocytic (HL60) cells along the granulocytic pathway are described here; to test their role on sensitivity of lymphoma cells to anti-lymphoma agents.

Isolamento de neutrófilos e análise para determinar seu papel na linfoma sensibilidade das células a agentes terapêuticos

Neutrophils are the most abundant (40% to 75%) type of white blood cells and among the first inflammatory cells to migrate towards the site of ...

Development of Stem Cell-derived Antigen-specific Regulatory T Cells Against Autoimmunity

Autoimmune diseases arise due to the loss of immunological self-tolerance. Regulatory T cells (Tregs) are important mediators of immunologic self-tolerance. Tregs represent about 5 - 10% of the mature CD4+ T cell subpopulation in mice and humans, with about 1 - 2% of those Tregs circulating in the peripheral blood. Induced pluripotent stem cells (iPSCs) can be differentiated into functional Tregs, which have a potential to be used for cell-based therapies of autoimmune diseases. Here, we present a method to develop antigen (Ag)-specific Tregs from iPSCs (i.e., iPSC-Tregs). The method is based on incorporating the transcription factor FoxP3 and an Ag-specific T cell receptor (TCR) into iPSCs and then differentiating on OP9 stromal cells expressing Notch ligands delta-like (DL) 1 and DL4. Following in vitro differentiation, the iPSC-Tregs express CD4, CD8, CD3, CD25, FoxP3, and Ag-specific TCR and are able to respond to Ag stimulation. This method has been successfully applied to cell-based therapy of autoimmune arthritis in a murine model. Adoptive transfer of these Ag-specific iPSC-Tregs into Ag-induced arthritis (AIA)-bearing mice has the ability to reduce joint inflammation and swelling and to prevent bone loss.

We present here a method to develop functional antigen (Ag)-specific regulatory T cells (Tregs) from induced pluripotent stem cells (iPSCs) for immunotherapy of autoimmune arthritis in a murine model.

Desenvolvimento de Células-Tronco de derivados de células T regulatórias antígeno específico da Contra Auto-imunidade

Autoimmune diseases arise due to the loss of immunological self-tolerance. Regulatory T cells (Tregs) are important mediators of immunologic ...

Use of the Soft-agar Overlay Technique to Screen for Bacterially Produced Inhibitory Compounds

The soft-agar overlay technique was originally developed over 70 years ago and has been widely used in several areas of microbiological research, including work with bacteriophages and bacteriocins, proteinaceous antibacterial agents. This approach is relatively inexpensive, with minimal resource requirements. This technique consists of spotting supernatant from a donor strain (potentially harboring a toxic compound(s)) onto a solidified soft agar overlay that is seeded with a bacterial test strain (potentially sensitive to the toxic compound(s)). We utilized this technique to screen a library of Pseudomonas syringae strains for intraspecific killing. By combining this approach with a precipitation step and targeted gene deletions, multiple toxic compounds produced by the same strain can be differentiated. The two antagonistic agents commonly recovered using this technique are bacteriophages and bacteriocins. These two agents can be differentiated using two simple additional tests. Performing a serial dilution on a supernatant containing bacteriophage will result in individual plaques becoming less in number with greater dilution, whereas serial dilution of a supernatant containing bacteriocin will result a clearing zone that becomes uniformly more turbid with greater dilution. Additionally, a bacteriophage will produce a clearing zone when spotted onto a fresh soft agar overlay seeded with the same strain, whereas a bacteriocin will not produce a clearing zone when transferred to a fresh soft agar lawn, owing to the dilution of the bacteriocin.

We describe a simple method for screening bacterial cultures for the production of compounds inhibitory towards other bacteria.

Uso da técnica de sobreposição de Soft-agar para triagem de compostos inibidores produzida por bactérias

The soft-agar overlay technique was originally developed over 70 years ago and has been widely used in several areas of microbiological research, ...

Combining Analysis of DNA in a Crude Virion Extraction with the Analysis of RNA from Infected Leaves to Discover New Virus Genomes

This metagenome approach is used to identify plant viruses with circular DNA genomes and their transcripts. Often plant DNA viruses that occur in low titers in their host or cannot be mechanically inoculated to another host are difficult to propagate to achieve a greater titer of infectious material. Infected leaves are ground in a mild buffer with optimal pH and ionic composition recommended for purifying most bacilliform Para retroviruses. Urea is used to break up inclusion bodies that trap virions and to dissolve cellular components. Differential centrifugation provides further separation of virions from plant contaminants. Then proteinase K treatment removes the capsids. Then the viral DNA is concentrated and used for next-generation sequencing (NGS). The NGS data are used to assemble contigs which are submitted to NCBI-BLASTn to identify a subset of virus sequences in the generated dataset. In a parallel pipeline, RNA is isolated from infected leaves using a standard column-based RNA extraction method. Then ribosome depletion is carried out to enrich for a subset of mRNA and virus transcripts. Assembled sequences derived from RNA sequencing (RNA-seq) were submitted to NCBI-BLASTn to identify a subset of virus sequences in this dataset. In our study, we identified two related full-length badnavirus genomes in the two datasets. This method is preferred to another common approach which extracts the aggregate population of small RNA sequences to reconstitute plant virus genomic sequences. This latter metagenomic pipeline recovers virus related sequences that are retro-transcribing elements inserted into the plant genome. This is coupled to biochemical or molecular assays to further discern the actively infectious agents. The approach documented in this study, recovers sequences representative of replicating viruses that likely indicate active virus infection.

Here we present a new approach to identify plant viruses with double-strand DNA genomes. We use standard methods to extract DNA and RNA from infected leaves and carry out next-generation sequencing. Bioinformatic tools assemble sequences into contigs, identify contigs representing virus genomes and assign genomes to taxonomic groups.

Combinando a análise de DNA em uma extração do Virion bruto com a análise do RNA das folhas infectadas para descobrir novos vírus de genomas

This metagenome approach is used to identify plant viruses with circular DNA genomes and their transcripts. Often plant DNA viruses that occur in low ...

Establishment of Viral Infection and Analysis of Host-Virus Interaction in Drosophila Melanogaster

Virus spreading is a major cause of epidemic diseases. Thus, understanding the interaction between the virus and the host is very important to extend our knowledge of prevention and treatment of viral infection. The fruit fly Drosophila melanogaster has proven to be one of the most efficient and productive model organisms to screen for antiviral factors and investigate virus-host interaction, due to powerful genetic tools and highly conserved innate immune signaling pathways. The procedure described here demonstrates a nano-injection method to establish viral infection and induce systemic antiviral responses in adult flies. The precise control of the viral injection dose in this method enables high experimental reproducibility. Protocols described in this study include the preparation of flies and the virus, the injection method, survival rate analysis, the virus load measurement, and an antiviral pathway assessment. The influence effects of viral infection by the flies' background were mentioned here. This infection method is easy to perform and quantitatively repeatable; it can be applied to screen for host/viral factors involved in virus-host interaction and to dissect the crosstalk between innate immune signaling and other biological pathways in response to viral infection.

Establishment of Viral Infection and Analysis of Host-Virus Interaction in Drosophila Melanogaster

This protocol describes how to establish viral infection in vivo in Drosophila melanogaster using the nano-injection method and basic techniques to analyze virus-host interaction.

Estabelecimento de infecção Viral e análise da interação vírus-hospedeiro em Drosophila Melanogaster.

Virus spreading is a major cause of epidemic diseases. Thus, understanding the interaction between the virus and the host is very important to extend our ...

Flow Cytometric Measurement Of ROS Production In Macrophages In Response To Fc&#947;R Cross-linking

The oxidative or respiratory burst is used to describe the rapid consumption of oxygen and generation of reactive oxygen species (ROS) by phagocytes in response to various immune stimuli. ROS generated during immune activation exerts potent antimicrobial activity primarily through the ability of ROS to damage DNA and proteins, causing death of microorganisms. Being able to measure ROS production reproducibly and with ease is necessary in order to assess the contribution of various pathways and molecules to this mechanism of host defense. In this paper, we demonstrate the use of fluorescent probes and flow cytometry to detect ROS production. Although widely used, fluorescent measurement of ROS is notoriously problematic, especially with regards to measurement of ROS induced by specific and not mitogenic stimuli. We present a detailed methodology to detect ROS generated as a result of specific Fc&#947;R stimulation beginning with macrophage generation, priming, staining, Fc&#947;R cross-linking, and ending with flow cytometric analysis.

Flow Cytometric Measurement Of ROS Production In Macrophages In Response To Fc&amp;#947;R Cross-linking

This study demonstrates the use of flow cytometry to detect reactive oxygen species (ROS) production resulting from activation of the Fc&#947;R. This method can be used to assess changes in the antimicrobial and redox signaling function of phagocytes in response to immune complexes, opsonized microorganisms, or direct Fc&#947;R cross-linking.

Fluxo Cytometric medição da produção de ROS em macrófagos em resposta a FcγR cross-linking

The oxidative or respiratory burst is used to describe the rapid consumption of oxygen and generation of reactive oxygen species (ROS) by phagocytes in ...