1. Inoculation et purification de virus VLP de plantes de Nicotiana benthamiana <ol><li> Produire plafonnées T7-ARN transcrits à partir de pommes de terre du virus X (PVX) à base de plasmides vecteurs transportant MRFV de type sauvage (wt) et protéine d&#39;enveloppe Cys-muté (CP) des gènes 12, en utilisant Ambion de T7-mMessage mMachine Kit. </li><li> Pour chaque réaction transcription T7, inoculer deux feuilles complètement développées de N. benthamiana avec 10 pi de réactions et incuber les plantes pendant 10 jours en serre à 60% d&#39;humidité pendant 16 heures avec de la lumière (25.000-30.000 lux) à 25 ° C et 8 h obscurité à 20 ° C. </li><li> Harves t N. benthamiana infectées par le virus laisse 10 jours après l&#39;inoculation (dpi), peser le tissu végétal (50 grammes) et le placer sur la glace. </li><li> Homogénéiser la matière végétale dans un malaxeur en présence de 100 ml d&#39;une solution glacée de 0,5 M Na-citrate, pH 5,5 (utilisation 2 ml de tampon par gramme de tissu végétal). </li><li> Filtrez homogénat par 3 couches de cheeseclOTH et de clarifier par centrifugation à 27.000 xg pendant 30 min. Transférer le surnageant dans une éprouvette graduée froide, mesurer le volume, puis transvaser dans un bécher stérile réfrigéré. Jeter le culot. </li><li> Traiter le surnageant par addition de polyéthylène glycol 10% 8.000 (PEG 8.000), sous agitation pendant 15 min à 4 ° C, et incuber pendant encore 45 min à 4 ° C pour précipiter les particules de type virus (VLP)-PEG matrice. </li><li> Centrifuger l&#39;échantillon à 27.000 xg pendant 20 min à 4 ° C et éliminer le surnageant. </li><li> Traiter la pastille en ajoutant 8 ml de 0,05 M citrate de Na-tampon, 5,5 contenant 2% de Triton X-100 pH. Swirl tubes à centrifuger le bien de libérer le culot. Transférer le culot et le tampon dans un bécher stérile réfrigéré. Rincer immédiatement les tubes de 2 ml du même tampon et ajouter dans le bécher. Agiter la suspension à 4 ° C jusqu&#39;à ce que les granules sont dissous (en général 1 heure). </li><li> Clarifier par centrifugation pendant 5 min à 27.000 xg, jeter le culot, et processus le surnageant par centrifugation à 140.000 xg pendant 2 heures à 4 ° C. </li><li> Remettre en suspension le culot dans 1 ml 0,05 M Na-citrate, pH 5,5, et de placer la suspension sur un gradient de saccharose 10-40% réalisés dans 0,05 M de Na-citrate, pH 5,5. </li><li> Centrifuger le gradient pendant 3 heures à 140.000 xg à 4 ° C. </li><li> Rayonner une lumière sur le dessus du tube de centrifugation et recueillir la bande de diffusion de lumière supérieure à 4 cm de la partie supérieure du tube, diluer avec 0,05 M Na-citrate, pH 5,5, et centrifuger pendant 3 heures à 140.000 xg à 4 ° C. </li><li> Reprendre le culot dans 0,5 ml d&#39;eau stérile et conserver à 4 ° C pendant un maximum de six mois. </li><li> Quantifier la concentration VLP en effectuant un dosage de protéine de Bradford. Le rendement de VLP est comprise entre 1 et 3 mg / g de tissu végétal. </li></ol> 2. Fluorescéine-5-maléimide-étiquetage Réactions des VLP <ol><li> Préparer une solution de 1 mM de fluorescéine-5-maléimide (427,37 g / mol) dans 50 mM de sodium phosphate tampon, pH 7,0; 1 mM EDTA. Mélanger à l&#39;aide du vortex et vérifier dissolution complète. Protéger le tube de la lumière en utilisant du papier d&#39;aluminium. </li><li> Ajouter fluorescéine-5-maléimide à VLP produites à l&#39;étape 1 et mélanger. Utiliser un excès 25-fois molaire de fluorescéine-5-maléimide de la quantité molaire de groupes sulfhydryle. En règle générale, l&#39;utilisation de VLP 30 pi à la concentration de 1 pg / pl et 60 ul de la solution de fluorescéine-5-maléimide produit des résultats acceptables. </li><li> Incuber la réaction pendant 2 heures à température ambiante ou une nuit à 4 ° C. </li><li> Mettre fin à la réaction par addition de dithiothreitol (DTT) à une concentration finale de 50 mM. </li><li> Retirer n&#39;ayant pas réagi fluorescéine en utilisant une colonne spin dessalage (Thermo Scientific Inc, Rockford IL) et centrifugation pendant 2 min à 1500 xg à température ambiante. </li><li> Pour analyse SDS-PAGE, ajouter 10 ul de 2 x SDS-PAGE tampon échantillon de Laemmli à 10 pl de chaque réaction. Rangez la protéine marquée abri de la lumière à 4 ° C pendant un mois ouà usage unique aliquots à -20 ° C jusqu&#39;à 3 mois. </li></ol> 3. Réaction de marquage et de détermination de constitution biotine <ol><li> Utilisez les colonnes de spin dessalage (Thermo Scientific Inc, Rockford IL) pour effectuer un échange de tampon de l&#39;eau de tampon phosphate salin (PBS), pH 7,0 des VLP produites à l&#39;étape 1. </li><li> Préparer une solution mère à 20 mM de maléimide PEG2-biotine en ajoutant ul 190 de PBS Non-Weigh-maléimide PEG2-biotine et mélanger par pipetage de haut en bas. </li><li> Ajouter maléimide PEG2-biotine pour les VLP et mélanger. Utiliser un excès 10-fois molaire de réactif de solutions VLP ≤ 2 mg / ml. </li><li> Incuber la réaction à température ambiante pendant 4 h. </li><li> Retirer n&#39;ayant pas réagi maléimide PEG2-biotine en utilisant une colonne spin dessalage (Thermo Scientific Inc, Rockford IL) et centrifugation pendant 2 min à 1500 xg à température ambiante. </li><li> Déterminer le nombre de moles de biotine par mole de VLP en utilisant la biotine Pierce Quantification Kit (Thermo Scientific) et following instructions du fabricant. </li></ol> 4. La réticulation de Cys 2-VLP et F Peptide <ol><li> VLP qui conduit à des résidus de cystéine disponibles pour la réticulation de l&#39;étape 2 (Cys 2-VLP) sont utilisés dans l&#39;étape suivante. Préparer une solution mère fraîche de réticulation (28,63 mM) en dissolvant 10 mg de NHS-PEG4-maléimide de réticulation en 680 ul de diméthylsulfoxyde. </li><li> Dissoudre un 17 (F)-amino peptide acide long (LLPNMOKDKEACAKAPL) dans 50 ul de tampon de conjugaison (1 x PBS, pH 7,2, 1 mM EDTA) à une concentration de 0,1 mM. </li><li> Ajouter 4 pl de réticulation à 50 ul du peptide dissous (protéine-NH2) à 1 mM concentration finale (qui est un excès de 10 fois molaire de 0,1 mM de solution de peptide). </li><li> Incuber la réaction pendant 2 heures à 4 ° C. </li><li> Purifier réticulé peptide en utilisant une colonne de dessalage (Thermo Scientific Inc, Rockford IL) équilibrée avec du tampon de conjugaison (1 x PBS, pH 7,2, 1 mM EDTA) par centrifugation à 1500 xgpendant 1 min à température ambiante. </li><li> Créer un mélange réactionnel combinant VLP (-protéine SH) et réticulé peptidiques (protéine-NH2) dans un rapport molaire déterminée par le nombre de thiols et amines activées intervenant dans la réaction et la différence de poids moléculaire entre VLP et peptidiques. </li><li> Incuber le mélange réactionnel à température ambiante pendant 2 heures à 4 ° C. </li><li> Pour l&#39;analyse par Western blot, mélanger le produit conjugué résultant 1:1 avec du tampon Laemmli, faire bouillir pendant 10 minutes, et de procéder à SDS-PAGE sur un casting de pré-10-20% Tris-Glycine gel (Invitrogen), suivie par un électrotransfert sur une membrane de nitrocellulose (Invitrogen). Bloquer les membranes avec 1 x PBS, pH 7,2 contenant 0,05% de Tween-20 (PBS-Tween) et 5% de poudre de lait écrémé et de la sonde avec le peptide anticorps spécifiques suivies par la phosphatase approprié anticorps secondaire marqué. </li></ol>

<ol>
	<li>Barnhill, H., Reuther, R., Ferguson, P. L., Dreher, T. W., Wang, Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Turnip+yellow+mosaic+virus+as+a+chemoaddressable+bionanoparticle.">Turnip yellow mosaic virus as a chemoaddressable bionanoparticle.</a> Bioconj. Chem. 18, 852-859 (2007).</li><li>Chapman, S., Kavanagh, T., Baulcombe, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Potato+virus+X+as+a+vector+for+gene+expression+in+plants.">Potato virus X as a vector for gene expression in plants.</a> Plant J. 2, 549-557 (1992).</li><li>Chen, C., Kwak, E. S., Stein, B., Kao, C. C., Dragnea, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Packaging+of+gold+particles+in+viral+capsids.">Packaging of gold particles in viral capsids.</a> J. Nanosci. Nanotechnol. 5, 2029-2033 (2005).</li><li>Fowler, C. E., Shenton, W., Stubbs, G., Mann, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tobacco+mosaic+virus+liquid+crystals+as+templates+for+the+interior+design+of+silica+mesophases+and+nanoparticles.">Tobacco mosaic virus liquid crystals as templates for the interior design of silica mesophases and nanoparticles.</a> Advanced Materials. 13, 1266-1269 (2001).</li><li>Gazit, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+biomolecular+templates+for+the+fabrication+of+metal+nanowires.">Use of biomolecular templates for the fabrication of metal nanowires.</a> FEBS. J. 274, 317-322 (2007).</li><li>Gillitzer, E., Wilts, D., Young, M., Douglas, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemical+modification+of+a+viral+cage+for+multivalent+presentation.">Chemical modification of a viral cage for multivalent presentation.</a> Chem. Commun. , 2390-2391 (2002).</li><li>Hammond, R. W., Hammond, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Maize+rayado+fino+virus+capsid+proteins+assemble+into+virus-like+particles+in+Escherichia+coli.">Maize rayado fino virus capsid proteins assemble into virus-like particles in Escherichia coli.</a> Virus Res. 147, 208-215 (2010).</li><li>Hermamson, G. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Bioconjugate techniques. , (1991).</li><li>Kaiser, C. R., Flenniken, M. L., Gillitzer, E., Harmsen, A. L., Harmsen, A. G., Jutila, M. A., Douglas, T., Young, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biodistribution+studies+of+protein+cage+nanoparticles+demonstrate+broad+tissue+distribution+and+rapid+clearance+in+vivo.">Biodistribution studies of protein cage nanoparticles demonstrate broad tissue distribution and rapid clearance in vivo.</a> Int. J. Nanomed. 2, 715-733 (2007).</li><li>Knez, M., Bittner, A. M., Boes, F., Wege, C., Jeske, H., Maisse, E., Kern, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biotemplate+synthesis+of+3-nm+nickel+and+cobalt+nanowires.">Biotemplate synthesis of 3-nm nickel and cobalt nanowires.</a> Nano Lett. 3, 1079-1082 (2003).</li><li>Lee, S. Y., Culver, J. N., Harris, M. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+CuCl2+concentration+on+the+aggregation+and+mineralization+of+Tobacco+mosaic+virus+biotemplate.">Effect of CuCl2 concentration on the aggregation and mineralization of Tobacco mosaic virus biotemplate.</a> J. Colloid. Interface. Sci. 297, 554-560 (2006).</li><li>Lvov, Y., Haas, H., Decher, G., Mohwald, H., Mikhailov, A., Mtchedlishvily, B., Morgunova, E., Vainshtein, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Successive+deposition+of+alternate+layers+of+polyelectrolytes+and+a+charged+virus.">Successive deposition of alternate layers of polyelectrolytes and a charged virus.</a> Langmuir. 10, 4232-4236 (1994).</li><li>Natilla, A., Hammond, R. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Maize+rayado+fino+virus+virus-like+particles+expressed+in+tobacco+plants:+a+new+platform+for+cysteine+selective+bioconjugation+peptide+display.">Maize rayado fino virus virus-like particles expressed in tobacco plants: a new platform for cysteine selective bioconjugation peptide display.</a> J. Virol. Methods. 178, 209-215 (2011).</li><li>Rae, C. S., Khor, I. W., Wang, Q., Destito, G., Gonzalez, M. J., Singh, P., Thomas, D. M., Estrada, M. N., Powell, E., Finn, M. G., Manchester, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Systemic+trafficking+of+plant+virus+nanoparticles+in+mice+via+the+oral+route.">Systemic trafficking of plant virus nanoparticles in mice via the oral route.</a> Virology. 343, 2224-2235 (2005).</li><li>Raja, K. S., Wang, Q., Gonzalez, M. J., Manchester, M., Johnson, J. E., Finn, M. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hybrid+virus-polymer+materials.+Synthesis+and+properties+of+PEG-decorated+Cowpea+mosaic+virus.">Hybrid virus-polymer materials. Synthesis and properties of PEG-decorated Cowpea mosaic virus.</a> Biomacromolecules. 4, 472-476 (2003).</li><li>Royston, E., Lee, S. Y., Culver, J. N., Harris, M. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+silica-coated+Tobacco+mosaic+virus.">Characterization of silica-coated Tobacco mosaic virus.</a> J. Colloid Interface Sci. 298, 706-712 (2006).</li><li>Schlick, T. L., Ding, Z., Kovacs, E. W., Francis, M. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dual-surface+modification+in+the+Tobacco+mosaic+virus.">Dual-surface modification in the Tobacco mosaic virus.</a> J. Am. Chem. Soc. 127, 3718-3723 (2005).</li><li>Young, M., Willits, D., Uchida, M., Douglas, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plant+viruses+as+biotemplates+for+materials+and+their+use+in+nanotechnology.">Plant viruses as biotemplates for materials and their use in nanotechnology.</a> Annu. Rev. Phytopathol. 46, 361-384 (2008).</li></ol>

La mention de noms commerciaux des produits commerciaux de la publication est uniquement dans le but de fournir des informations précises et n&#39;implique pas de recommandation ou une approbation par le Département américain de l&#39;Agriculture.

La méthode présentée ici permet une analyse très sensible et rapide de cystéines réactives présentes sur la surface de particules de type viral de plantes produites ainsi que tous les autres complexes protéiques. Maléimides sont thiol-spécifique des réactifs, qui réagissent avec sulfhydryle libres des molécules contenant de former des liaisons thioéther stable. Cette méthode s&#39;appuie sur la spécificité des maléimides à réagir avec des groupes sulfhydryle pas impliqués dans les interactions avec ...

<table border="1"><tbody><tr><td> Nom du réactif </td><td> Entreprise </td><td> Numéro de catalogue </td><td> Commentaires </td></tr><tr><td> Thinwall, Ultra-Clear Tubes </td><td> Beckman </td><td> 344059 </td><td></td></tr><tr><td> mMESSAGE mMACHINE T7 Kit </td><td> Tecnologies vie </td><td> AM1344M </td><td></td></tr><tr><td> Fluorescéine-5-maléimide </td><td> Thermo Scientific Technologies de la vie </td><td> 46130 F150 </td><td> 46130 est hors de substitution afin d&#39;F150 </td></tr><tr><td> Kit de quantification Pierce biotine </td><td> Thermo Scientific </td><td> 28005 </td><td></td></tr><tr><td> EZ-Link Maleimide-PEG2-Biotine, Non-Weigh Format </td><td> Thermo Scientific </td><td> 21901 </td><td></td></tr><tr><td> SM (PEG) n Réticulants </td><td> Thermo Scientific </td><td> 22107 </td><td></td></tr><tr><td> 10-20% de Tris-Glycine gel </td><td> Invitrogen </td><td> EC61352 </td><td></td></tr><tr><td> Tampon Laemmli </td><td> Bio-Rad </td><td> 1610737 </td><td></td></tr><tr><td> Tris Glycine SDS Exécution tampon </td><td> Invitrogen </td><td> LC2675 </td><td></td></tr><tr><td> Tris Glycine transfert Tampon </td><td> Invitrogen </td><td> LC3675 </td><td></td></tr><tr><td> Membrane de nitrocellulose papier filtre Sandwich </td><td> Invitrogen </td><td> LC2001 </td><td></td></tr><tr><td> Affinity phosphatase marqué anticorps purifiés à IgG de lapin </td><td> Kirkegaard et Perry Laboratories </td><td> 0751516 </td><td></td></tr><tr><td> Substrat de la phosphatase NBT / BCIP </td><td> Kirkegaard et 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

Imitant et l&#39;exploitation de propriétés du virus et les caractéristiques physico-chimiques et physiques promet d&#39;apporter des solutions à certains des défis les plus urgents de la planète. La multitude et les types de virus associés à leurs propriétés intrigantes potentiellement donner des possibilités infinies pour les applications dans les technologies à base de virus. Les virus ont la capacité de s&#39;auto-assembler en particules de forme discrète et la taille, la spécificité de symétrie, la polyvalence, et des propriétés stables dans une large gamme de conditions de température et de pH. Sans surprise, avec une gamme remarquable de propriétés, les virus sont proposés pour être utilisés dans les biomatériaux 9, 14, 15 vaccins, du matériel électronique, des outils et des produits chimiques, l&#39;électronique moléculaire conteneurs 4, 5, 10, 11, 16, 18, ​​12. Afin d&#39;utiliser les virus dans les nanotechnologies, elles doivent être modifiées de leurs formes naturelles pour donner de nouvelles fonctions. Ce défi processus peut être réalisée par plusieurs mécanismes comprenant la modification génétique du génome viral et la fixation chimique des molécules étrangères ou souhaitée pour les groupes réactifs des particules virales 8. La possibilité de modifier un virus dépend essentiellement des propriétés physico-chimiques et physiques du virus. En outre, les modifications génétiques ou physico-chimique doivent être effectuées sans affecter la structure du virus indigène et le fonctionnement du virus. Protéines de maïs rayado fino virus manteau (MRFV) s&#39;auto-assembler dans Escherichia coli produisant des VLP stables et vides qui sont stabilisées par protéine-protéine interactions et qui peut être utilisé dans les applications des technologies à base de virus 8. VLP produites dans des plants de tabac ont été examinés comme un échafaudage sur lequel une variété de peptides peuvent être affichés de manière covalente 13. Ici, nous décrivons les étapes 1) à déterminer lequel des cystéines accessibles au solvant dans une capside du virus sont disponibles pour les modification, et 2) Bioconjugate peptides modifiés pour les capsides. En utilisant indigènes ou par mutation-inséré résidus d&#39;acides aminés et des standards des technologies de couplage, une grande variété de matériaux ont été affichées sur la surface des virus de plantes tels que le virus de la mosaïque de Brome 3, virus de la panachure Carnation 12, niébé virus de la marbrure chlorotique 6, la mosaïque du tabac virus 17, virus de la mosaïque jaune navet 1, et MRFV 13.

L&#39;expression transitoire de mutants MRFV manteau de protéines (CP) des gènes dans N. benthamiana dans un vecteur PVX VLP à base produisant est décrit dans la figure 1. Le gène modifié MRFV protéine d&#39;enveloppe est amplifié par PCR puis placé sous le contrôle transcriptionnel du promoteur subgénomique CP dupliqué dans un vecteur PVX-base, pP2C2S 2, (un cadeau de D. Baulcombe, Laboratoires Sainsbury, Norwich, Angleterre). En vitro transcription de l&#39;ARN...

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

Procédé pour analyser l&#39;accessibilité au solvant du groupe thiol de résidus cystéine de<em&gt; Cueilleur rayado fino virus</em&gt; (MRFV)-particules de type virus (VLP) suivi d&#39;un peptide réaction de réticulation est décrit. La méthode tire parti de la disponibilité de plusieurs groupes chimiques à la surface des particules de type viral qui peuvent être les cibles de réactions spécifiques.

L&#39;analyse de l&#39;accessibilité au solvant des résidus de cystéine sur<em&gt; Cueilleur rayado fino virus</em&gt; Virus-like particles produits dans<em&gt; Nicotiana benthamiana</em&gt; Plantes et réticulation des peptides à 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 vues.  Agricultural Research Service, United States Department of Agriculture. Procédé pour analyser l'accessibilité au solvant du groupe thiol de résidus cystéine de Cueilleur rayado fino virus (MRFV)-particules de type virus (VLP) suivi d'un peptide réaction de réticulation est décrit. La méthode tire parti de la disponibilité de plusieurs groupes chimiques à la surface des particules de type viral qui peuvent être les cibles de réactions spécifiques.

Vidéo: 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.

L&#39;isolement et l&#39;analyse du génome des virions unique en utilisant la génomique du virus unique »

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

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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

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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.

Analyse in vitro de la réponse immunitaire cellulaire Myd88 médiation au virus du Nil occidental souche mutante 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.

Modélisation du cycle de vie du virus Ebola Sous biosécurité de niveau 2 Conditions de particules de type viral contenant Tetracistronic minigénomes

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.

Neutrophiles Isolement et analyse pour déterminer leur rôle dans le lymphome cellulaire Sensibilité aux agents thérapeutiques

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.

Développement de cellules souches dérivées de cellules T régulatrices spécifiques de l&#39;antigène contre Autoimmunité

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.

L&#39;utilisation de la technique de superposition Soft-agar à l&#39;écran pour les composés inhibitrices produites par voie bactérienne

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.

Combinant l’analyse de l’ADN dans une Extraction de Virion brut avec l’analyse de l’ARN des feuilles infectées pour découvrir de nouveaux génomes de Virus

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.

Mise en place d’une Infection virale et analyse de l’Interaction hôte-Virus chez 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.

Mesure de débit par cytométrie en flux de Production de ROS dans les Macrophages en réponse à la réticulation FcγR

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