Le financement a été fourni par Fight for Sight et de la recherche pour prévenir la cécité.

1. Une dissection du segment antérieur. <ol><li> Tissus scléral en arrière du limbe est saisi avec une pince de 0,22 et le globe (globe oculaire) est stabilisé. </li><li> Une lame de microchirurgie est utilisé pour faire une incision linéaire dans la cornée de limbe à limbe. </li><li> A 0,12 Colibri pince est ensuite utilisé pour saisir la cornée à l&#39;incision. </li><li> Le fluide de la chambre antérieure est alors absorbée par une lance Weck-Cel chirurgicale. </li></ol> 2. L&#39;éviscération Lens. <ol><li> Une pince 0,12 Colibri saisissant la cornée est utilisé pour stabiliser le monde. </li><li> Un porte-aiguille fine courbe (ou courbes pinces à pansement) est inséré derrière la lentille vers la face postérieure de la planète. Le porte-aiguille est partiellement fermée, et tiré vers l&#39;avant. La pression est appliquée à l&#39;aide de la pince sur la surface externe de la sclérotique, qui pousse la lentille vers l&#39;avant dans l&#39;incision cornéenne, tout en laissant le mur oeil intact. Le vitré apparaît comme un gel translucide et est partiellement adhérente à la lentille. </li><li> Le tissu lentille vitreuse est ensuite placé dans un tube de centrifugation filtrée contenant 20 microlitres de cocktail inhibiteur de protéase (Roche) dissous dans du PBS. </li></ol> 3. L&#39;éviscération rétine. <ol><li> Continuer à stabiliser le globe avec une pince Colibri 0,12 saisir l&#39;incision cornéenne. </li><li> Un porte-aiguille fine courbe (ou courbes pinces à pansement) est placé aussi loin postérieure à la planète que possible, à proximité du nerf optique. Le porte-aiguille est partiellement fermée, et tiré vers l&#39;avant. La pression est appliquée à l&#39;aide de la pince sur la surface externe de la sclérotique, qui pousse vers l&#39;avant de la rétine à travers l&#39;incision cornéenne. Le vitré apparaît comme un gel translucide adhérente à la rétine. La rétine est visualisé comme une jaune, tissu vascularisé. Tout bandes de tissu pigmentées peuvent être décollées avec une pince. </li><li> Le tissu rétine vitreuse est ensuite placé dans le tube à centrifuger filtrée contenant le tissu lentille vitreuse. </li></ol> 4. Filtrée par centrifugation. <ol><li> Le tube de centrifugeuse filtré est placé dans une centrifugeuse de paillasse. Centrifuger à 14000 g pendant 12 minutes. </li><li> Aspirer l&#39;éluant de la chambre inférieure, qui est le corps vitré. La rétine reste dans la chambre supérieure. Ces échantillons peuvent être utilisées pour les études des protéines. </li></ol> 5. Les résultats représentatifs Échantillons vitrifiée été analysées par SDS-PAGE (figure 2). Des échantillons ont également été utilisés pour un test d&#39;activité enzymatique (figure 3). <img src="/files/ftp_upload/2795/2795fig1.jpg" alt="Figure 1"/> Figure 1. Diagramme de l&#39;œil de la souris. Transversale schématique de l&#39;œil humain et de la souris indique le volume vitré relativement petite dans l&#39;oeil de la souris en raison de sa grande lentille. <img src="/files/ftp_upload/2795/2795fig2.jpg" alt="Figure 2"/> Figure 2. Unidimensionnelle SDS-PAGE de la souris vitrée et la rétine. Profils protéiques du corps vitré de la souris, 13,6 mg / ml (voie 1), et de la rétine, 11,35 mg / mL (piste 2). L&#39;électrophorèse sur gel a été réalisée à 150 kV pendant 45 minutes, colorées avec du gel Flamingo tache fluorescente et visualisées à l&#39;aide d&#39;un système d&#39;imagerie VersaDoc (BioRad, Hercules, CA). <img src="/files/ftp_upload/2795/2795fig3.jpg" alt="Figure 3"/> Figure 3. Enzyme superoxyde dismutase activité (SOD) chez la souris et du vitré humain. Mesure de l&#39;activité SOD totale (SOD activité colorimétrique aasay kit, # AB65354, Abcam, Inc, Cambridge, MA) a été réalisée sur vitré et la rétine recueillies par l&#39;éviscération des souris DBA et albinos. Ceci a été comparé à l&#39;activité de la SOD dans le noyau du vitré humain et rétine humaine recueillies post-mortem yeux donneur humain pour déterminer l&#39;activité relative. Non dilué des échantillons de carottes ont été manuellement vitreuse aspiration avec une aiguille de calibre 23, 11 et de la rétine ont été recueillies par la floraison, les yeux et couper le tissu loin du complexe RPE / choroïde. Bien que l&#39;essai ne fait pas de distinction entre les isoformes de SOD, l&#39;activité SOD vitré est susceptible de refléter SOD3, puisque c&#39;est la seule isoforme extracellulaire 12 L&#39;activité de la SOD rétine est susceptible de refléter toutes les isoformes de SOD trois:. Intracellulaires SOD1, mitochondriale SOD2 et extracellulaire SOD3. 12 Pour très sensible dosages enzymatiques, y compris ce test SOD, la possibilité de contamination croisée des protéines est possible et nécessite une étude plus approfondie. Les barres d&#39;erreur représentent SEM.

<ol>
	<li>Bishop, P. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structural+macromolecules+and+supramolecular+organisation+of+the+vitreous+gel.">Structural macromolecules and supramolecular organisation of the vitreous gel.</a> Prog. Retin. Eye Res. 19, 323-344 (2000).</li><li>Gao, B. B., Chen, X., Timothy, N., Aiello, L. P. &. a. m. p. ;. a. m. p., Feener, E. P. <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+the+vitreous+proteome+in+diabetes+without+diabetic+retinopathy+and+diabetes+with+proliferative+diabetic+retinopathy.">Characterization of the vitreous proteome in diabetes without diabetic retinopathy and diabetes with proliferative diabetic retinopathy.</a> J. Proteome Res. 7, 2516-2525 (2008).</li><li>Izuta, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extracellular+SOD+and+VEGF+are+increased+in+vitreous+bodies+from+proliferative+diabetic+retinopathy+patients.">Extracellular SOD and VEGF are increased in vitreous bodies from proliferative diabetic retinopathy patients.</a> Mol. Vis. 15, 2663-2672 (2009).</li><li>Sebag, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+biology+of+pharmacologic+vitreolysis.">Molecular biology of pharmacologic vitreolysis.</a> Trans. Am. Ophthalmol. Soc. 103, 473-494 (2005).</li><li>Smith, R. S., Smith, R. S., John, S. W. M., Nishina, P. M., Sundberg, 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=.">.</a> Systematic evaluation of the mouse eye: Anatomy, pathology, and biomethods. , 161-195 (2002).</li><li>Ihanamaki, T., Metsaranta, M., Rintala, M., Vuorio, E., Sandberg-Lall, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ocular+abnormalities+in+transgenic+mice+harboring+mutations+in+the+type+II+collagen+gene.">Ocular abnormalities in transgenic mice harboring mutations in the type II collagen gene.</a> Eur. J. Ophthalmol. 6, 427-435 (1996).</li><li>Kaarniranta, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+mouse+model+for+Stickler's+syndrome:+ocular+phenotype+of+mice+carrying+a+targeted+heterozygous+inactivation+of+type+II+(pro)collagen+gene+(Col2a1.">A mouse model for Stickler's syndrome: ocular phenotype of mice carrying a targeted heterozygous inactivation of type II (pro)collagen gene (Col2a1.</a> Exp. Eye Res. 83, 297-303 (2006).</li><li>Marneros, A. G. &. a. m. p. ;. a. m. p., Olsen, B. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Age-dependent+iris+abnormalities+in+collagen+XVIII/endostatin+deficient+mice+with+similarities+to+human+pigment+dispersion+syndrome.">Age-dependent iris abnormalities in collagen XVIII/endostatin deficient mice with similarities to human pigment dispersion syndrome.</a> Invest. Ophthalmol. Vis. Sci. 44, 2367-2372 (2003).</li><li>Martin, A. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pathogenesis+of+persistent+hyperplastic+primary+vitreous+in+mice+lacking+the+arf+tumor+suppressor+gene.">Pathogenesis of persistent hyperplastic primary vitreous in mice lacking the arf tumor suppressor gene.</a> Invest. Ophthalmol. Vis. Sci. 45, 3387-3396 (2004).</li><li>Song, B. J., Tsang, S. H., Lin, C. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetic+models+of+retinal+degeneration+and+targets+for+gene+therapy.">Genetic models of retinal degeneration and targets for gene therapy.</a> Gene. Ther. Mol. Biol. 11B, 229-262 (2007).</li><li>Skeie, J. M., Mahajan, V. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dissection+of+Human+Vitreous+Body+Elements+for+Proteomic+Analysis.">Dissection of Human Vitreous Body Elements for Proteomic Analysis.</a> J Vis Exp. , (2011).</li><li>Ciechanowski, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impaired+synthesis+is+not+the+reason+for+decreased+activity+of+extracellular+superoxide+dismutase+in+patients+with+diabetes.">Impaired synthesis is not the reason for decreased activity of extracellular superoxide dismutase in patients with diabetes.</a> Arch Med Res. 36, 148-153 (2005).</li></ol>

Expériences sur les animaux ont été effectuées en conformité avec l&#39;Association pour la Recherche et de la Vision dans la déclaration d&#39;ophtalmologie pour l&#39;utilisation d&#39;animaux à la recherche ophtalmique et Vision.

Les souris transgéniques sont un modèle important pour étudier les maladies de la rétine et vitréo-rétinienne. 6-10 Le corps vitré de la souris, cependant, comporte une proportion significativement plus faible de l&#39;œil en comparaison avec le corps vitré humaine en raison de la grande lentille dans l&#39;oeil de la souris. Cela fait 5 il est difficile d&#39;isoler et de purifier le corps vitré de la souris. Comprendre les changements associés à la protéine du vitré au cours des maladies telles que la rétinopathie diabétique proliférative, la dégénérescence maculaire liée à l&#39;âge, l&#39;uvéite et décollement de la rétine va donner un aperçu des mécanismes par lesquels ils progressent. Ce protocole expérimental visualisés fournit un moyen d&#39;obtenir et de purifier le corps vitré de la souris, tout en maximisant le rendement de protéines pour les analyses enzymatiques et protéomiques.

<table border="1"><tbody><tr><th> Nom </th><th> Société </th><th> Nombre de catalogue </th><th> Commentaires </th></tr><tr><td> 15 °, BD Beaver microchirurgie lame </td><td> Becton-Dickinson </td><td> 374881 </td><td></td></tr><tr><td> PBS, pH 7,4 </td><td> Invitrogen </td><td> 70011-044 </td><td></td></tr><tr><td> 0,22 Beaux-Castroviejo forceps Suture </td><td> Storz Ophthalmics </td><td> E1805 </td><td></td></tr><tr><td> 0,12 Colibri pince </td><td> Storz Ophthalmics </td><td> 2 / 132 </td><td></td></tr><tr><td> Microcon centrifuge Filtre Ultracel YM-100 ou YM-50 </td><td> Millipore </td><td> 42412, 42415 </td><td></td></tr><tr><td> Activité SOD Assay Kit colorimétrique </td><td> Abcam </td><td> Ab65354 </td><td></td></tr><tr><td> Weck-Cel chirurgicale lances </td><td> Medtronic </td><td> 0008680 </td><td></td></tr><tr><td> Cocktails d&#39;inhibiteurs de protéase </td><td> Roche </td><td> 11 836 170 001 </td><td></td></tr><tr><td> Flamingo fluorescentes gel de coloration </td><td> Bio-Rad </td><td> 161-04910 </td><td></td></tr></tbody></table>

evisceration of mouse vitreous and retina for proteomic analyses

Alors que la rétine de souris a émergé comme un modèle important génétique pour la maladie rétinienne héréditaire, le vitré de la souris reste à explorer. Le vitré est une matrice extracellulaire fortement aqueux recouvrant la rétine où intraoculaire ainsi que des protéines extra s&#39;accumuler pendant la maladie. 1-3 interactions anormales entre vitré et la rétine sous-tendent plusieurs maladies telles que le décollement de la rétine, rétinopathie diabétique proliférative, l&#39;uvéite et vitréorétinopathie proliférante 1. , 4 Le volume relatif du vitré de la souris est nettement plus petit que le corps vitré de l&#39;homme (figure 1), puisque l&#39;objectif de souris occupe près de 75% de ses yeux. 5 Cela a fait des études biochimiques du corps vitré de souris défi. Dans cet article, vidéo, nous présentons une technique de disséquer et d&#39;isoler le corps vitré de la rétine de souris, ce qui permettra l&#39;utilisation de modèles de souris transgéniques pour définir plus clairement le rôle de cette matrice extracellulaire dans le développement de maladies vitréo-rétinienne.

Watch this Scientific Journal Video about Evisceration of Mouse Vitreous and Retina for Proteomic Analyses at JoVE.com

Evisceration of Mouse Vitreous and Retina for Proteomic Analyses

La technique de dissection illustre l&#39;éviscération du vitré, la rétine et le cristallin de l&#39;oeil de la souris, une séparation par centrifugation, et la caractérisation des dosages de protéines.

L&#39;éviscération des corps vitré et la rétine de la souris pour les analyses protéomiques

While the mouse retina has emerged as an important genetic model for inherited retinal disease, the mouse vitreous remains to be explored. The vitreous is ...

evisceration-of-mouse-vitreous-and-retina-for-proteomic-analyses

Research

JoVE Journal

Biology

28.9K vues.  University of Iowa. La technique de dissection illustre l'éviscération du vitré, la rétine et le cristallin de l'oeil de la souris, une séparation par centrifugation, et la caractérisation des dosages de protéines.

Vidéo: Evisceration of Mouse Vitreous and Retina for Proteomic Analyses

Electrophoretic Separation of Proteins

Electrophoresis is used to separate complex mixtures of proteins (e.g., from cells, subcellular fractions, column fractions, or immunoprecipitates), to investigate subunit compositions, and to verify homogeneity of protein samples. It can also serve to purify proteins for use in further applications. In polyacrylamide gel electrophoresis, proteins migrate in response to an electrical field through pores in a polyacrylamide gel matrix; pore size decreases with increasing acrylamide concentration. The combination of pore size and protein charge, size, and shape determines the migration rate of the protein. In this unit, the standard Laemmli method is described for discontinuous gel electrophoresis under denaturing conditions, i.e., in the presence of sodium dodecyl sulfate (SDS). 

In this video, we demonstrate a method for electrophoretic separation of proteins using poly-acrylimide gel electrophoresis (PAGE).

Séparation électrophorétique de protéines

Electrophoresis is used to separate complex mixtures of proteins (e.g., from cells, subcellular fractions, column fractions, or immunoprecipitates), to ...

Recherche

Biologie

Immunoblot Analysis

Immunoblotting (western blotting) is a rapid and sensitive assay for the detection and characterization of proteins that works by exploiting the specificity inherent in antigen-antibody recognition. It involves the solubilization and electrophoretic separation of proteins, glycoproteins, or lipopolysaccharides by gel electrophoresis, followed by quantitative transfer and irreversible binding to nitrocellulose, PVDF, or nylon. The immunoblotting technique has been useful in identifying specific antigens recognized by polyclonal or monoclonal antibodies and is highly sensitive (1 ng of antigen can be detected). This unit provides protocols for protein separation, blotting proteins onto membranes, immunoprobing, and visualization using chromogenic or chemiluminescent substrates.

Immunoblotting (western blotting) is a rapid and sensitive assay for the detection and characterization of proteins that works by exploiting the specificity inherent in antigen-antibody recognition. This video provides protocols for protein separation, blotting proteins onto membranes, immunoprobing, and visualization using chromogenic or chemiluminescent substrates.

Analyse immunoblot

Immunoblotting (western blotting) is a rapid and sensitive assay for the detection and characterization of proteins that works by exploiting the ...

Digital Microfluidics for Automated Proteomic Processing

Clinical proteomics has emerged as an important new discipline, promising the discovery of biomarkers that will be useful for early diagnosis and prognosis of disease. While clinical proteomic methods vary widely, a common characteristic is the need for (i) extraction of proteins from extremely heterogeneous fluids (i.e. serum, whole blood, etc.) and (ii) extensive biochemical processing prior to analysis. Here, we report a new digital microfluidics (DMF) based method integrating several processing steps used in clinical proteomics. This includes protein extraction, resolubilization, reduction, alkylation and enzymatic digestion. Digital microfluidics is a microscale fluid-handling technique in which nanoliter-microliter sized droplets are manipulated on an open surface. Droplets are positioned on top of an array of electrodes that are coated by a dielectric layer - when an electrical potential is applied to the droplet, charges accumulate on either side of the dielectric. The charges serve as electrostatic handles that can be used to control droplet position, and by biasing a sequence of electrodes in series, droplets can be made to dispense, move, merge, mix, and split on the surface. Therefore, DMF is a natural fit for carrying rapid, sequential, multistep, miniaturized automated biochemical assays. This represents a significant advance over conventional methods (relying on manual pipetting or robots), and has the potential to be a useful new tool in clinical proteomics.
Mais J. Jebrail, Vivienne N. Luk, and Steve C. C. Shih contributed equally to this work.
Sergio L. S. Freire's current address is at the University of the Sciences in Philadelphia located at 600 South 43rd Street, Philadelphia, PA 19104.

Digital Microfluidics is a technique characterized by the manipulation of discrete droplets (~nL - mL) on an array of electrodes by the application of electrical fields. It is well-suited for carrying out rapid, sequential, miniaturized automated biochemical assays. Here, we report a platform capable of automating several proteomic processing steps.

Microfluidique numérique pour le traitement automatisé protéomiques

Clinical proteomics has emerged as an important new discipline, promising the discovery of biomarkers that will be useful for early diagnosis and ...

Toxin Induction and Protein Extraction from Fusarium spp. Cultures for Proteomic Studies

Fusaria are filamentous fungi able to produce different toxins. Fusarium mycotoxins such as deoxynivalenol, nivalenol, T2, zearelenone, fusaric acid, moniliformin, etc... have adverse effects on both human and animal health and some are considered as pathogenicity factors. Proteomic studies showed to be effective for deciphering toxin production mechanisms (Taylor et al., 2008) as well as for identifying potential pathogenic factors (Paper et al., 2007, Houterman et al., 2007) in Fusaria. It becomes therefore fundamental to establish reliable methods for comparing between proteomic studies in order to rely on true differences found in protein expression among experiments, strains and laboratories. The procedure that will be described should contribute to an increased level of standardization of proteomic procedures by two ways. The filmed protocol is used to increase the level of details that can be described precisely. Moreover, the availability of standardized procedures to process biological replicates should guarantee a higher robustness of data, taking into account also the human factor within the technical reproducibility of the extraction procedure.
The protocol described requires 16 days for its completion: fourteen days for cultures and two days for protein extraction (figure 1). 
Briefly, Fusarium strains are grown on solid media for 4 days; they are then manually fragmented and transferred into a modified toxin inducing media (Jiao et al., 2008) for 10 days. Mycelium is collected by filtration through a Miracloth layer. Grinding is performed in a cold chamber. Different operators performed extraction replicates (n=3) in order to take into account the bias due to technical variations (figure 2). Extraction was based on a SDS/DTT buffer as described in Taylor et al. (2008) with slight modifications. Total protein extraction required a precipitation process of the proteins using Aceton/TCA/DTT buffer overnight and Acetone /DTT washing (figure 3a,3b). Proteins were finally resolubilized in the protein-labelling buffer and quantified. Results of the extraction were visualized on a 1D gel (Figure 4, SDS-PAGE), before proceeding to 2D gels (IEF/SDS-PAGE). The same procedure can be applied for proteomic analyses on other growing media and other filamentous fungi (Miles et al., 2007).

Toxin Induction and Protein Extraction from Fusarium spp. Cultures for Proteomic Studies

Protein extraction for proteomic analyses in fungal species requires high levels of standardization to be accomplished according with the minimum information about a proteomic experiment (MIAPE) guidelines. We present a video-protocol that includes a procedure for minimizing experimental bias during toxin induction and protein extraction from Fusarium spp.

L&#39;induction ou à toxines et d&#39;extraction de protéines à partir Fusarium Spp. Cultures pour les études protéomiques

Fusaria are filamentous fungi able to produce different toxins. Fusarium mycotoxins such as deoxynivalenol, nivalenol, T2, zearelenone, fusaric acid, ...

In vivo Imaging and Therapeutic Treatments in an Orthotopic Mouse Model of Ovarian Cancer

Human cancer and response to therapy is better represented in orthotopic animal models. This paper describes the development of an orthotopic mouse model of ovarian cancer, treatment of cancer via oral delivery of drugs, and monitoring of tumor cell behavior in response to drug treatment in real time using in vivo imaging system. In this orthotopic model, ovarian tumor cells expressing luciferase are applied topically by injecting them directly into the mouse bursa where each ovary is enclosed. Upon injection of D-luciferin, a substrate of firefly luciferase, luciferase-expressing cells generate bioluminescence signals. This signal is detected by the in vivo imaging system and allows for a non-invasive means of monitoring tumor growth, distribution, and regression in individual animals. Drug administration via oral gavage allows for a maximum dosing volume of 10 mL/kg body weight to be delivered directly to the stomach and closely resembles delivery of drugs in clinical treatments. Therefore, techniques described here, development of an orthotopic mouse model of ovarian cancer, oral delivery of drugs, and in vivo imaging, are useful for better understanding of human ovarian cancer and treatment and will improve targeting this disease.

In vivo Imaging and Therapeutic Treatments in an Orthotopic Mouse Model of Ovarian Cancer

Orthotopic animal models of ovarian cancer replicate better human disease and therefore enhance our understanding of cancer progression and tumor response to therapy. A mouse model receives an intrabursal injection of luciferase-expressing ovarian tumor cells. Treatment is administered via oral gavage. Tumor growth is monitored by in vivo imaging system.

L&#39;imagerie in vivo et des traitements thérapeutiques dans un modèle de souris orthotopique de cancer des ovaires

Human cancer and response to therapy is better represented in orthotopic animal models.  This paper describes the development of an orthotopic mouse model ...

Isolation of Translating Ribosomes Containing Peptidyl-tRNAs for Functional and Structural Analyses

Recently, structural and biochemical studies have detailed many of the molecular events that occur in the ribosome during inhibition of protein synthesis by antibiotics and during nascent polypeptide synthesis. Some of these antibiotics, and regulatory nascent polypeptides mostly in the form of peptidyl-tRNAs, inhibit either peptide bond formation or translation termination1-7. These inhibitory events can stop the movement of the ribosome, a phenomenon termed "translational arrest". Translation arrest induced by either an antibiotic or a nascent polypeptide has been shown to regulate the expression of genes involved in diverse cellular functions such as cell growth, antibiotic resistance, protein translocation and cell metabolism8-13. Knowledge of how antibiotics and regulatory nascent polypeptides alter ribosome function is essential if we are to understand the complete role of the ribosome in translation, in every organism.
Here, we describe a simple methodology that can be used to purify, exclusively, for analysis, those ribosomes translating a specific mRNA and containing a specific peptidyl-tRNA14. This procedure is based on selective isolation of translating ribosomes bound to a biotin-labeled mRNA. These translational complexes are separated from other ribosomes in the same mixture, using streptavidin paramagnetic beads (SMB) and a magnetic field (MF). Biotin-labeled mRNAs are synthesized by run-off transcription assays using as templates PCR-generated DNA fragments that contain T7 transcriptional promoters. T7 RNA polymerase incorporates biotin-16-UMP from biotin-UTP; under our conditions approximately ten biotin-16-UMP molecules are incorporated in a 600 nt mRNA with a 25% UMP content. These biotin-labeled mRNAs are then isolated, and used in in vitro translation assays performed with release factor 2 (RF2)-depleted cell-free extracts obtained from Escherichia coli strains containing wild type or mutant ribosomes. Ribosomes translating the biotin-labeled mRNA sequences are stalled at the stop codon region, due to the absence of the RF2 protein, which normally accomplishes translation termination. Stalled ribosomes containing the newly synthesized peptidyl-tRNA are isolated and removed from the translation reactions using SMB and an MF. These beads only bind biotin-containing messages.
The isolated, translational complexes, can be used to analyze the structural and functional features of wild type or mutant ribosomal components, or peptidyl-tRNA sequences, as well as determining ribosome interaction with antibiotics or other molecular factors 1,14-16. To examine the function of these isolated ribosome complexes, peptidyl-transferase assays can be performed in the presence of the antibiotic puromycin1. To study structural changes in translational complexes, well established procedures can be used, such as i) crosslinking to specific amino acids14 and/or ii) alkylation protection assays1,14,17.

A major impediment to biochemical analyses of ribosomes containing nascent peptidyl-tRNAs has been the presence of other ribosomes in the same samples, ribosomes not involved in the translation of the specific mRNA sequence being analyzed. We developed a simple methodology to purify, exclusively, the ribosomes containing the nascent peptidyl-tRNA of interest.

Isolement des ribosomes Traduire Contenant Peptidyl-ARNt pour des analyses fonctionnelles et structurelles

Recently, structural and biochemical studies have detailed many of the molecular events that occur in the ribosome during inhibition of protein synthesis ...

In vivo Electroporation of Morpholinos into the Adult Zebrafish Retina

Many devastating inherited eye diseases result in progressive and irreversible blindness because humans cannot regenerate dying or diseased retinal neurons. In contrast, the adult zebrafish retina possesses the robust ability to spontaneously regenerate any neuronal class that is lost in a variety of different retinal damage models, including retinal puncture, chemical ablation, concentrated high temperature, and intense light treatment 1-8. Our lab extensively characterized regeneration of photoreceptors following constant intense light treatment and inner retinal neurons after intravitreal ouabain injection 2, 5, 9. In all cases, resident M&uuml;ller glia re-enter the cell cycle to produce neuronal progenitors, which continue to proliferate and migrate to the proper retinal layer, where they differentiate into the deficient neurons. 
	We characterized five different stages during regeneration of the light-damaged retina that were highlighted by specific cellular responses. We identified several differentially expressed genes at each stage of retinal regeneration by mRNA microarray analysis 10. Many of these genes are also critical for ocular development. To test the role of each candidate gene/protein during retinal regeneration, we needed to develop a method to conditionally limit the expression of a candidate protein only at times during regeneration of the adult retina. 
	Morpholino oligos are widely used to study loss of function of specific proteins during the development of zebrafish, Xenopus, chick, mouse, and tumors in human xenografts 11-14. These modified oligos basepair with complementary RNA sequence to either block the splicing or translation of the target RNA. Morpholinos are stable in the cell and can eliminate or "knockdown" protein expression for three to five days 12. 
	Here, we describe a method to efficiently knockdown target protein expression in the adult zebrafish retina. This method employs lissamine-tagged antisense morpholinos that are injected into the vitreous of the adult zebrafish eye. Using electrode forceps, the morpholino is then electroporated into all the cell types of the dorsal and central retina. Lissamine provides the charge on the morpholino for electroporation and can be visualized to assess the presence of the morpholino in the retinal cells. 
	Conditional knockdown in the retina can be used to examine the role of specific proteins at different times during regeneration. Additionally, this approach can be used to study the role of specific proteins in the undamaged retina, in such processes as visual transduction and visual processing in second order neurons.

In vivo Electroporation of Morpholinos into the Adult Zebrafish Retina

A method to conditionally knockdown a target protein&#x2019;s expression in the adult zebrafish retina is described, which involves intravitreally injecting antisense morpholinos and electroporating them into the retina. The resulting protein is knocked down for several days, which allows testing the protein&#x2019;s role in the regenerating or intact retina.

En électroporation in vivo de morpholinos dans la rétine de poisson zèbre adulte

Many devastating inherited eye diseases result in progressive and irreversible blindness because humans cannot regenerate dying or diseased retinal ...

Trajectory Data Analyses for Pedestrian Space-time Activity Study

It is well recognized that human movement in the spatial and temporal dimensions has direct influence on disease transmission1-3. An infectious disease typically spreads via contact between infected and susceptible individuals in their overlapped activity spaces. Therefore, daily mobility-activity information can be used as an indicator to measure exposures to risk factors of infection. However, a major difficulty and thus the reason for paucity of studies of infectious disease transmission at the micro scale arise from the lack of detailed individual mobility data. Previously in transportation and tourism research detailed space-time activity data often relied on the time-space diary technique, which requires subjects to actively record their activities in time and space. This is highly demanding for the participants and collaboration from the participants greatly affects the quality of data4.
Modern technologies such as GPS and mobile communications have made possible the automatic collection of trajectory data. The data collected, however, is not ideal for modeling human space-time activities, limited by the accuracies of existing devices. There is also no readily available tool for efficient processing of the data for human behavior study. We present here a suite of methods and an integrated ArcGIS desktop-based visual interface for the pre-processing and spatiotemporal analyses of trajectory data. We provide examples of how such processing may be used to model human space-time activities, especially with error-rich pedestrian trajectory data, that could be useful in public health studies such as infectious disease transmission modeling.
The procedure presented includes pre-processing, trajectory segmentation, activity space characterization, density estimation and visualization, and a few other exploratory analysis methods. Pre-processing is the cleaning of noisy raw trajectory data. We introduce an interactive visual pre-processing interface as well as an automatic module. Trajectory segmentation5 involves the identification of indoor and outdoor parts from pre-processed space-time tracks. Again, both interactive visual segmentation and automatic segmentation are supported. Segmented space-time tracks are then analyzed to derive characteristics of one's activity space such as activity radius etc. Density estimation and visualization are used to examine large amount of trajectory data to model hot spots and interactions. We demonstrate both density surface mapping6 and density volume rendering7. We also include a couple of other exploratory data analyses (EDA) and visualizations tools, such as Google Earth animation support and connection analysis. The suite of analytical as well as visual methods presented in this paper may be applied to any trajectory data for space-time activity studies.

A suite of spatiotemporal processing methods are presented to analyze human trajectory data, such as that collected using a GPS device, for the purpose of modeling pedestrian space-time activities.

Les analyses des données de trajectoire pour étudier l&#39;activité piétonne l&#39;espace-temps

It is well recognized that human movement in the  spatial and temporal dimensions has direct influence on disease transmission1-3.  An infectious disease ...

Metabolic Labeling and Membrane Fractionation for Comparative Proteomic Analysis of Arabidopsis thaliana Suspension Cell Cultures

Plasma membrane microdomains are features based on the physical properties of the lipid and sterol environment and have particular roles in signaling processes. Extracting sterol-enriched membrane microdomains from plant cells for proteomic analysis is a difficult task mainly due to multiple preparation steps and sources for contaminations from other cellular compartments. The plasma membrane constitutes only about 5-20% of all the membranes in a plant cell, and therefore isolation of highly purified plasma membrane fraction is challenging. A frequently used method involves aqueous two-phase partitioning in polyethylene glycol and dextran, which yields plasma membrane vesicles with a purity of 95% 1. Sterol-rich membrane microdomains within the plasma membrane are insoluble upon treatment with cold nonionic detergents at alkaline pH. This detergent-resistant membrane fraction can be separated from the bulk plasma membrane by ultracentrifugation in a sucrose gradient 2. Subsequently, proteins can be extracted from the low density band of the sucrose gradient by methanol/chloroform precipitation. Extracted protein will then be trypsin digested, desalted and finally analyzed by LC-MS/MS. Our extraction protocol for sterol-rich microdomains is optimized for the preparation of clean detergent-resistant membrane fractions from Arabidopsis thaliana cell cultures.
We use full metabolic labeling of Arabidopsis thaliana suspension cell cultures with K15NO3 as the only nitrogen source for quantitative comparative proteomic studies following biological treatment of interest 3. By mixing equal ratios of labeled and unlabeled cell cultures for joint protein extraction the influence of preparation steps on final quantitative result is kept at a minimum. Also loss of material during extraction will affect both control and treatment samples in the same way, and therefore the ratio of light and heave peptide will remain constant. In the proposed method either labeled or unlabeled cell culture undergoes a biological treatment, while the other serves as control 4.

Metabolic Labeling and Membrane Fractionation for Comparative Proteomic Analysis of Arabidopsis thaliana Suspension Cell Cultures

Here we describe a robust method for the fractionation of plant plasma membranes into detergent resistant and detergent soluble membranes based on a mixture of unlabeled and in vivo fully 15N labeled Arabidopsis thaliana cell cultures. The procedure is applied for comparative proteomic studies to understand signaling processes.

Marquage métabolique et la membrane de fractionnement pour comparative Analyse protéomique de<em&gt; Arabidopsis thaliana</em&gt; Cultures Suspension cellulaires

Plasma membrane microdomains are features based on the physical properties of the lipid and sterol environment and have particular roles in signaling ...

Extraction of Venom and Venom Gland Microdissections from Spiders for Proteomic and Transcriptomic Analyses

Venoms are chemically complex secretions typically comprising numerous proteins and peptides with varied physiological activities. Functional characterization of venom proteins has important biomedical applications, including the identification of drug leads or probes for cellular receptors. Spiders are the most species rich clade of venomous organisms, but the venoms of only a few species are well-understood, in part due to the difficulty associated with collecting minute quantities of venom from small animals. This paper presents a protocol for the collection of venom from spiders using electrical stimulation, demonstrating the procedure on the Western black widow (Latrodectus hesperus). The collected venom is useful for varied downstream analyses including direct protein identification via mass spectrometry, functional assays, and stimulation of venom gene expression for transcriptomic studies. This technique has the advantage over protocols that isolate venom from whole gland homogenates, which do not separate genuine venom components from cellular proteins that are not secreted as part of the venom. Representative results demonstrate the detection of known venom peptides from the collected sample using mass spectrometry. The venom collection procedure is followed by a protocol for dissecting spider venom glands, with results demonstrating that this leads to the characterization of venom-expressed proteins and peptides at the sequence level.

This article provides a protocol for the extraction of venom from spiders using electrical stimulation in order to 1) conduct proteomic characterization, 2) stimulate venom gland gene expression, and 3) perform functional studies of venoms. This is followed by a description of venom gland microdissections for gene expression studies.