Il nostro lavoro è supportato anche da finanziamenti NIH / NIGMS, NSF, USDA / NIFA e BARD a VC.

Fondo Symplastic trasporto di macromolecole attraverso connessioni impianto intercellulari, il plasmodesmi, è di interesse per molti patologi vegetali e biologi. Per esempio, diverse proteine ​​virali sono noti per regolare plasmodesmal limiti di esclusione dimensioni per permettere il movimento virale 1-3. Inoltre, alcune proteine ​​endogene, tra i quali importanti regolatori dello sviluppo, si presume per passare da una cella all&#39;altra, presumibilmente attraverso plasmodesmi, per funzionare non-cell-autonomo 4. Così, una metodologia affidabile per identificare e visualizzare il trasporto macromolecolare tra cellule vegetali è molto richiesto. 1) Far crescere le piantine bersaglio Per la trasformazione ad alta efficienza, piante sane, robuste dovrebbe essere usato. 1. Arabidopsis piante Crescere una pianta di Arabidopsis su Pro-Mix BX in un vaso (10 cm x 10 cm x 10 cm) in un ambiente controllato da camera con un fotoperiodo breve (8 ore di 130-150 μE m -2 s -1 luce a 23 ° C/16 ore al buio a 20 ° C) e del 40-65% di umidità relativa da 6 a 8 settimane 5. Fecondarle tanto in tanto con prodotti disponibili in commercio, come descritto 5. Foglie con la dimensione maggiore di 15 mm x 35 mm (la misura di lunghezza include picciolo) vengono selezionati per gli esperimenti. 2. N. benthamiana e N. tabacum Cresce una pianta su Pro-Mix BX in un vaso (20 cm x 20 cm x 20 cm) in un ambiente controllato da camera con un fotoperiodo lungo (16 ore di 130-150 μE m -2 s -1 luce a 23 ° C / 8 ore al buio a 20 ° C) e del 40-65% di umidità relativa da 7 a 10 settimane. Fecondarle tanto in tanto con prodotti disponibili in commercio come descrivere. Foglie con dimensioni maggiori di 50 mm x 70 mm per N. benthamiana, o 100 mm x 125 mm per N. tabacum (queste misure di lunghezza non comprendono picciolo) vengono selezionati per gli esperimenti. 2) Preparazione della cartuccia Gene Gun con DNA microparticelle rivestite d&#39;oro Il protocollo per questa fase sperimentale è stato descritto in dettaglio in precedenza 6. E &#39;molto importante usare bene purificato il DNA plasmidico ad alte concentrazioni (~ 1 mg / mL) per ottenere la massima efficienza di trasformazione per la facilità di analisi di microscopia confocale durante le fasi successive della sperimentazione. Per questo test, è importante accertarsi che la cartuccia preparato non trasformare due o più celle adiacenti contemporaneamente ad alta frequenza, perché i numeri di cellule associazione con un cluster segnale fluorescente viene utilizzato come indicatore del grado di trasporto symplastic (cioè , una singola cellula che contiene il segnale indica nessun movimento, mentre un cluster segnale multicella indica il movimento). La qualità dei ogni cartuccia può essere verificato analizzando l&#39;espressione della proteina 16-20 dopo bombardamento ore. Il nostro protocollo 6 produce cartucce che producono cluster espressione multicella solo in &lt;3% di tutti gli eventi espressione in questo lasso di tempo, quindi adatto per questo esperimento. 3) Consegna Biolistic di microparticelle rivestite di DNA <ol><li> Togliere le foglie della stessa fase di sviluppo (cioè con le stesse dimensioni e stessa età, vedi punto 1) con una lama di rasoio affilato e immediatamente posto con i lati abaxial rivolto verso l&#39;alto su una superficie piana di polistirolo. Il lato abaxial della foglia rappresenta un substrato migliore per il bombardamento a causa della sua densità tricomi più basso e più sottile cuticola. Foglie di Arabidopsis, a causa delle loro dimensioni relativamente piccole, dovrebbero essere coperti con un pezzo di maglia finestra dello schermo, e la rete poi fissato con pushpins alla superficie di polistirolo. Il mantenimento di foglie piatte aumenta l&#39;efficienza della consegna delle particelle e riduce al minimo i danni al tessuto durante microbombardment. </li><li> Inserire la cartuccia con microparticelle rivestite di DNA (preparata al punto 1) nella pistola. Per Arabidopsis, il tiro viene eseguita a pressioni di 80-110 psi per 1-micron microparticelle, e 140-160 psi per 0,6 micron microparticelle. Per N. benthamiana e tabacco, il tiro viene eseguita a pressioni di 100-120 psi per 1-micron microparticelle, e 160-180 psi per 0,6 micron microparticelle. Per Arabidopsis, di solito si utilizza una cartuccia per anta, in quanto ogni foglia ha uno spazio sufficiente superficie per un solo colpo microparticelle che si estende su una superficie di 10-12 mm di diametro. Con grande N. benthamiana e foglie di tabacco, bombardamenti multipli della stessa foglia sono possibili, tuttavia, deve essere fatto nelle posizioni simmetriche ai lati della venatura di indirizzare le aree foglia allo stesso stadio di sviluppo (vedi Discussione). </li><li> Togliere le foglie dalla superficie di polistirolo e li hoNon una piastra di Petri, il 3 strati di carta bagnata Whatman filtro, sigillare la piastra di Petri con Parafilm, e incubare a temperatura ambiente per 36-48 ore per consentire l&#39;espressione dei transgeni consegnato e il potenziale cellula-cellula movimento dei loro prodotti proteici . </li></ol> 4) Imaging di espressione proteica Il segnale di fluorescenza delle proteine ​​espresse transitoriamente tag è visualizzata mediante microscopia confocale. Si deve prestare attenzione per trovare le impostazioni ottimali per il rilevamento microscopia di ogni proteina testato. Per esempio, le proteine ​​che mostrano limitato accumulo intracellulare con intensità di segnale debole, come ad esempio la localizzazione della proteina plasmodesmal movimento virus del mosaico del tabacco (TMV MP) 1-3,6, deve essere osservata sotto una lente obiettivo 40X, che offre una risoluzione più alta e sensibilità, mentre le proteine ​​che mostrano la distribuzione citoplasmatica con intensità segnale forte, come la connessione YFP, possono essere visualizzati sotto una lente obiettivo 10X con funzione di zoom per una più rapida l&#39;imaging confocale (vedi Figura 1). Trasporto Symplastic è dedotta dalla comparsa di cluster multicella che contengono il segnale fluorescente. Il numero di tali aggregati e il numero di cellule in ogni cluster è indicativo del grado di cellula-cellula di trasporto. Per ottenere dati affidabili, almeno 100 cluster espressione dovrebbe essere registrate per ogni sistema sperimentale. Per esempio, se la cellula-cellula movimento di una proteina è confrontato in due diversi sfondi genetici (per esempio, di tipo selvatico e piante transgeniche), su un totale di 200 ammassi espressione dovrebbe essere registrato. Soprattutto, esperimenti, i cui risultati devono essere confrontati gli uni agli altri, deve essere effettuata contemporaneamente. 5. Rappresentante Risultati La figura seguente illustra gli esperimenti di rappresentanza per il rilevamento di trasporto symplastic delle proteine ​​fluorescenti tag. Pannelli A e B mostrano le immagini tipiche confocale che si ottengono microbombardment seguito di una N. foglia benthamiana con un MP TMV-YFP che esprimono costruire. Nel pannello A, movimento symplastic di TMV MP-YFP si osserva basa sulla comparsa di grappoli multicella del segnale YFP. Non tutti i transitoriamente espressa TMV MP-YFP è in grado di muoversi come evidenziato da singole cellule del segnale in alcune microbombardments (pannello B). Statisticamente, in &lt;40% dei glomeruli segnale contati, TMV MP-YFP è in grado di spostarsi tra le celle mentre nel&gt; 60% dei glomeruli, la proteina si muove tra 2-5 cellule, con le due celle diffuso è il più frequente (ca. casi ~ 50%) (Figura 1C). Le proteine ​​con relativamente piccole dimensioni molecolari in assenza di attività moto innato può diffondersi attraverso il PD per spostare cellula-cellula. Per esempio, YFP libero, o 1xYFP (ca. 27 kDa, pannello D), si diffonde tra le diverse celle nel 30% dei glomeruli contati (pannelli C). Questo non specifici diffusione non si verifica per un dimmer YFP traslazionale, o 2xYFP (54 kDa, e pannello), che è paragonabile per dimensioni a TMV MP-YFP proteina di fusione (57 kDa), e che è completamente cellule autonome (Figura 1C). <img src="/files/ftp_upload/2208/2208fig1.jpg" alt="Figura 1" /> Risultati Figura 1. Tipici ottenuti dal test di trasporto symplastic in N. benthamiana foglia tessuti. (A, B) Visualizzazione del TMV MP-YFP. (C) Quantificazione dei cluster segnale. 1xYFP e 2xYFP, libero YFP e traslazionale YFP dimero, rispettivamente. (D) Visualizzazione 1xYFP. (E) Visualizzazione 2xYFP. In micrografie, i pannelli sinistra mostrano il segnale YFP e pannelli di destra mostrano le immagini fuse di YFP (in verde) e autofluorescenza cloroplasto (in bianco) i segnali. Le immagini sono singole sezioni confocale. Asterischi nei micrografie mostrano le cellule epidermiche che mostra segnali YFP. Bar = 50 micron.

<ol>
	<li>Waigmann, E., Ueki, S., Trutnyeva, K., Citovsky, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+ins+and+outs+of+non-destructive+cell-to-cell+and+systemic+movement+of+plant+viruses.+.">The ins and outs of non-destructive cell-to-cell and systemic movement of plant viruses. .</a> Crit Rev Plant Sci. 23, 195-250 (2004).</li><li>Lucas, W. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plant+viral+movement+proteins:+agents+for+cell-to-cell+trafficking+of+viral+genomes.">Plant viral movement proteins: agents for cell-to-cell trafficking of viral genomes.</a> Virology. 344, 169-184 (2006).</li><li>Epel, B. L. <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+spread+by+diffusion+on+ER-associated+movement-protein-rafts+through+plasmodesmata+gated+by+viral+induced+host+beta-1,3-glucanases.">Plant viruses spread by diffusion on ER-associated movement-protein-rafts through plasmodesmata gated by viral induced host beta-1,3-glucanases.</a> Semin Cell Dev Biol. 20, 1074-1081 (2009).</li><li>Zambryski, P. 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G., Citovsky, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+transient+genetic+transformation+of+Arabidopsis+leaves+by+biolistic+bombardment.">Functional transient genetic transformation of Arabidopsis leaves by biolistic bombardment.</a> Nat Protoc. 4, 71-77 (2009).</li><li>Oparka, K. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simple,+but+not+branched,+plasmodesmata+allow+the+nonspecific+trafficking+of+proteins+in+developing+tobacco+leaves.">Simple, but not branched, plasmodesmata allow the nonspecific trafficking of proteins in developing tobacco leaves.</a> Cell. 97, 743-754 (1999).</li><li>Imlau, A., Truernit, E., Sauer, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell-to-cell+and+long-distance+trafficking+of+the+green+fluorescent+protein+in+the+phloem+and+symplastic+unloading+of+the+protein+into+sink+tissues.">Cell-to-cell and long-distance trafficking of the green fluorescent protein in the phloem and symplastic unloading of the protein into sink tissues.</a> Plant Cell. 11, 309-322 (1999).</li><li>Gisel, A., Barella, S., Hempel, F. D., Zambryski, P. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temporal+and+spatial+regulation+of+symplastic+trafficking+during+development+in+Arabidopsis+thaliana+apices.">Temporal and spatial regulation of symplastic trafficking during development in Arabidopsis thaliana apices.</a> Development. 126, 1879-1889 (1999).</li><li>Kim, I., Cho, E., Crawford, K. M., Hempel, F. D., Zambryski, P. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell-to-cell+movement+of+GFP+during+embryogenesis+and+early+seedling+development+in+Arabidopsis.">Cell-to-cell movement of GFP during embryogenesis and early seedling development in Arabidopsis.</a> Proc Natl Acad Sci USA. 102, 2227-2231 (2005).</li><li>Crawford, K. M., Zambryski, P. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Non-targeted+and+targeted+protein+movement+through+plasmodesmata+in+leaves+in+different+developmental+and+physiological+states.">Non-targeted and targeted protein movement through plasmodesmata in leaves in different developmental and physiological states.</a> Plant Physiol. 125, 1802-1812 (2001).</li><li>Roberts, A. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phloem+unloading+in+sink+leaves+of+Nicotiana+benthamiana:+comparison+of+a+fluorescent+solute+with+a+fluorescent+virus.">Phloem unloading in sink leaves of Nicotiana benthamiana: comparison of a fluorescent solute with a fluorescent virus.</a> Plant Cell. 9, 1381-1396 (1997).</li><li>Guenoune-Gelbart, D., Elbaum, M., Sagi, G., Levy, A., Epel, B. L. <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+(TMV)+replicase+and+movement+protein+function+synergistically+in+facilitating+TMV+spread+by+lateral+diffusion+in+the+plasmodesmal+desmotubule+of+Nicotiana+benthamiana.">Tobacco mosaic virus (TMV) replicase and movement protein function synergistically in facilitating TMV spread by lateral diffusion in the plasmodesmal desmotubule of Nicotiana benthamiana.</a> Mol Plant Microbe Interact. 21, 335-345 (2008).</li></ol>

Nessun conflitto di interessi dichiarati.

La chiave per il successo del saggio di trasporto symplastic è quello di ottenere elevata efficienza di trasformazione, che consente la produzione di cluster segnale statisticamente significativi e facilmente misurabili. Ciò può essere ottenuto utilizzando le foglie raccolte da piante sane, robuste, e la preparazione di particelle di oro rivestite da una preparazione del DNA puro e concentrato. Utilizzando le foglie in fase di crescita stessa è fondamentale anche per l&#39;affidabilità del test. Plasmodesmal apertura è noto per essere regolati in modo differenziato, a seconda della fase di sviluppo del tessuto 7-11. Foglie di molte specie di piante sviluppano basipetally, dal vertice alla base, con la parte apicale della foglia di essere più maturo della sua parte basale 12. Così, non solo lo stadio di sviluppo delle foglie (di solito riflesso dalla loro dimensioni e la posizione sullo stelo) selezionati per ogni set di esperimenti dovrebbero essere identici, ma le aree foglia bersaglio microbombardment deve essere posizionato nelle posizioni identiche. Alcuni studi precedenti hanno utilizzato cellule autonome marcatori, come il reticolo endoplasmatico-tethered GFP (erGFP) 11, di distinguere le cellule inizialmente trasformato da quelli a cui la proteina testate si è mosso con i mezzi symplastic. Tuttavia, un successivo studio ha mostrato che l&#39;espressione simultanea di alcuni non-cellule autonome proteine ​​con erGFP potrebbe indurre la cellula-cellula movimento 13, mettere in discussione l&#39;affidabilità di erGFP come marcatori prima trasformazione e sostanzialmente aumentando la difficoltà di interpretazione dei dati da esperimenti di coespressione del genere. Così, preferiamo evitare di introdurre l&#39;espressione di un&#39;altra proteina nelle nostre analisi del movimento, e, invece, si basano su analisi statistica dei numeri di cluster segnale.

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<td>Gold microparticles, 1.0 &mu;m in diameter</td>
<td>&nbsp;</td>
<td>Bio-Rad</td>
<td>165-2262</td>
<td>&nbsp;</td>
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<td>Gold microparticles, 0.6 &mu;m in diameter</td>
<td>&nbsp;</td>
<td>Bio-Rad</td>
<td>165-2263</td>
<td>&nbsp;</td>
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<td>Spermidine</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>S0266-1G</td>
<td>&nbsp;</td>
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<td>Tefzel tubing</td>
<td>&nbsp;</td>
<td>Bio-Rad</td>
<td>165-2441</td>
<td>&nbsp;</td>
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<td>Helios cartridge preparatory station</td>
<td>&nbsp;</td>
<td>Bio-Rad</td>
<td>165-2420</td>
<td>&nbsp;</td>
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<td>Tubing cutter</td>
<td>&nbsp;</td>
<td>Bio-Rad</td>
<td>165-2422</td>
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<td>Helios gene gun</td>
<td>&nbsp;</td>
<td>Bio-Rad</td>
<td>165-2432</td>
<td>&nbsp;</td>
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<td>Helium gas regulator</td>
<td>&nbsp;</td>
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a cell-to-cell macromolecular transport assay in planta utilizing biolistic bombardment

Qui, vi presentiamo un protocollo semplice e rapido per rilevare e valutare l&#39;entità del cellula-cellula trasporto macromolecolari in planta. In questo protocollo, una fluorescente con tag proteina di interesse è transitoriamente espressa in tessuti vegetali dopo la consegna biolistic del suo DNA codifica costruire. La distribuzione intra-ed intercellulare della proteina tag viene quindi analizzato al microscopio confocale. Descriviamo questa tecnologia nel dettaglio, fornendo passo-passo protocolli di saggiare e valutare l&#39;entità del trasporto delle proteine ​​symplastic in tre specie di piante, Arabidopsis thaliana, Nicotiana benthamiana e N. tabacum (tabacco).

Watch this Scientific Journal Video about A Cell-to-cell Macromolecular Transport Assay in Planta Utilizing Biolistic Bombardment at JoVE.com

A Cell-to-cell Macromolecular Transport Assay in Planta Utilizing Biolistic Bombardment

Traffico macromolecolari tra le cellule delle piante può essere valutata transitoriamente esprimere una proteina fluorescente-tagged di interesse e per analizzarne la distribuzione intra-ed intercellulare mediante microscopia confocale.

Una cellula-cellula Macromolecole saggio di trasporto In Planta Utilizzando Bombardamento Biolistic

Here, we present a simple and rapid protocol to detect and assess the extent of cell-to-cell macromolecular transport in planta. In this protocol, a ...

a-cell-to-cell-macromolecular-transport-assay-planta-utilizing

Universidad San Sebastian

Research

JoVE Journal

Biology

A Cell-to-cell Macromolecular Transport Assay in Planta Utilizing Biolistic Bombardment

11.8K Views.  State University of New York at Stony Brook. Traffico macromolecolari tra le cellule delle piante può essere valutata transitoriamente esprimere una proteina fluorescente-tagged di interesse e per analizzarne la distribuzione intra-ed intercellulare mediante microscopia confocale.

Video: A Cell-to-cell Macromolecular Transport Assay in Planta Utilizing Biolistic Bombardment

Preparation of Gene Gun Bullets and Biolistic Transfection of Neurons in Slice Culture

Biolistic transfection is a physical means of transfecting cells by bombarding tissue with high velocity DNA coated particles. We provide a detailed protocol for biolistic transfection of rat hippocampal slices, from the initial preparation of DNA coated bullets to the final shooting of the organotypic slice cultures using a gene gun. Gene gun transfection is an efficient and easy means of transfecting neurons and is especially useful for fluorescently labeling a small subset of cells in tissue slice. In this video, we first outline the steps required to coat gold particles with DNA. We next demonstrate how to line the inside of plastic tubing with the gold/DNA bullets, and how to cut this tubing to obtain the plastic cartridges for loading into the gene gun. Finally, we perform biolistic transfection of rat hippocampal slice cultures, demonstrating handling of the Bio-Rad Helios gene gun, and offering trouble shooting advice to obtain healthy and optimally transfected tissue slices.  

We describe a method for preparing DNA coated gold bullets and demonstrate the use of such bullets to biolistically transfect neurons in cultured hippocampal slices.

Preparazione di proiettili pistola Gene e Biolistic Transfection dei neuroni in cultura Slice

Biolistic transfection is a physical means of transfecting cells by bombarding tissue with high velocity DNA coated particles. We provide a detailed ...

Ricerca

Biologia

Window on a Microworld: Simple Microfluidic Systems for Studying Microbial Transport in Porous Media

Microbial growth and transport in porous media have important implications for the quality of groundwater and surface water, the recycling of nutrients in the environment, as well as directly for the transmission of pathogens to drinking water supplies. Natural porous media is composed of an intricate physical topology, varied surface chemistries, dynamic gradients of nutrients and electron acceptors, and a patchy distribution of microbes. These features vary substantially over a length scale of microns, making the results of macro-scale investigations of microbial transport difficult to interpret, and the validation of mechanistic models challenging. Here we demonstrate how simple microfluidic devices can be used to visualize microbial interactions with micro-structured habitats, to identify key processes influencing the observed phenomena, and to systematically validate predictive models. Simple, easy-to-use flow cells were constructed out of the transparent, biocompatible and oxygen-permeable material poly(dimethyl siloxane). Standard methods of photolithography were used to make micro-structured masters, and replica molding was used to cast micro-structured flow cells from the masters. The physical design of the flow cell chamber is adaptable to the experimental requirements: microchannels can vary from simple linear connections to complex topologies with feature sizes as small as 2 &mu;m. Our modular EcoChip flow cell array features dozens of identical chambers and flow control by a gravity-driven flow module. We demonstrate that through use of EcoChip devices, physical structures and pressure heads can be held constant or varied systematically while the influence of surface chemistry, fluid properties, or the characteristics of the microbial population is investigated. Through transport experiments using a non-pathogenic, green fluorescent protein-expressing Vibrio bacterial strain, we illustrate the importance of habitat structure, flow conditions, and inoculums size on fundamental transport phenomena, and with real-time particle-scale observations, demonstrate that microfluidics offer a compelling view of a hidden world.

Microfluidic devices can be used to visualize complex natural processes in real time and at the appropriate physical scales. We have developed a simple microfluidic device that mimics key features of natural porous media for studying growth and transport of bacteria in the subsurface.

Finestra su un micromondo: Sistemi Microfluidic semplice per studiare il trasporto microbica in mezzi porosi

Microbial growth and transport in porous media have important implications for the quality of groundwater and surface water, the recycling of nutrients in ...

Generation of Transgenic C. elegans by Biolistic Transformation

The number of laboratories using the free living nematode C. elegans is rapidly growing. The popularity of this biological model is attributed to a rapid generation time and short life span, easy and inexpensive maintenance, fully sequenced genome, and array of RNAi resources and mutant animals. Additionally, analysis of the C. elegans genome revealed a great similarity between worms and higher vertebrates, which suggests that research in worms could be an important adjunct to studies performed in whole mice or cultured cells. A powerful and important part of worm research is the ability to use transgenic animals to study gene localization and function. Transgenic animals can be created either via microinjection of the worm germline or through the use of biolistic bombardment. Bombardment is a newer technique and is less familiar to a number of labs. Here we describe a simple protocol to generate transgenic worms by biolistic bombardment with gold particles using the Bio-Rad PDS-1000 system. Compared with DNA microinjection into hermaphrodite germline, this protocol has the advantage of not requiring special skills from the operator with regards to identifying worm anatomy or performing microinjection. Further multiple transgenic lines are usually obtained from a single bombardment. Also in contrast to microinjection, biolistic bombardment produces transgenic animals with both extrachromosomal arrays and integrated transgenes. The ability to obtain integrated transgenic lines can avoid the use of mutagenic protocols to integrate foreign DNA. In conclusion, biolistic bombardment can be an attractive method for the generation of transgenic animals, especially for investigators not interested in investing the time and effort needed to become skilled at microinjection.

Generation of Transgenic C. elegans by Biolistic Transformation

Transgenic worms are commonly used in C. elegans research. Described is a simple, yet effective, protocol to introduce transgenes into worms using biolistic bombardment with DNA-coated gold particles. The effort involved and results of bombardment compare favorably with microinjection for the generation of transgenic animals.

Generazione di transgenici C. elegans Di Trasformazione Biolistic

The number of laboratories using the free living nematode C. elegans is rapidly growing. The popularity of this biological model is attributed to a rapid ...

Agrobacterium-Mediated Virus-Induced Gene Silencing Assay In Cotton

Cotton (Gossypium hirsutum) is one of the most important crops worldwide. Considerable efforts have been made on molecular breeding of new varieties. The large-scale gene functional analysis in cotton has been lagged behind most of the modern plant species, likely due to its large size of genome, gene duplication and polyploidy, long growth cycle and recalcitrance to genetic transformation1. To facilitate high throughput functional genetic/genomic study in cotton, we attempt to develop rapid and efficient transient assays to assess cotton gene functions.
Virus-Induced Gene Silencing (VIGS) is a powerful technique that was developed based on the host Post-Transcriptional Gene Silencing (PTGS) to repress viral proliferation2,3. Agrobacterium-mediated VIGS has been successfully applied in a wide range of dicots species such as Solanaceae, Arabidopsis and legume species, and monocots species including barley, wheat and maize, for various functional genomic studies3,4. As this rapid and efficient approach avoids plant transformation and overcomes functional redundancy, it is particularly attractive and suitable for functional genomic study in crop species like cotton not amenable for transformation.
In this study, we report the detailed protocol of Agrobacterium-mediated VIGS system in cotton. Among the several viral VIGS vectors, the tobacco rattle virus (TRV) invades a wide range of hosts and is able to spread vigorously throughout the entire plant yet produce mild symptoms on the hosts5. To monitor the silencing efficiency, GrCLA1, a homolog gene of Arabidopsis Cloroplastos alterados 1 gene (AtCLA1) in cotton, has been cloned and inserted into the VIGS binary vector pYL156. CLA1 gene is involved in chloroplast development6, and previous studies have shown that loss-of-function of AtCLA1 resulted in an albino phenotype on true leaves7, providing an excellent visual marker for silencing efficiency. At approximately two weeks post Agrobacterium infiltration, the albino phenotype started to appear on the true leaves, with 100% silencing efficiency in all replicated experiments. The silencing of endogenous gene expression was also confirmed by RT-PCR analysis. Significantly, silencing could potently occur in all the cultivars we tested, including various commercially grown varieties in Texas. This rapid and efficient Agrobacterium-mediated VIGS assay provides a very powerful tool for rapid large-scale analysis of gene functions at genome-wide level in cotton.

We present the detailed protocol for Agrobacterium-mediated virus-induced gene silencing (VIGS) assay in cotton. The tobacco rattle virus (TRV)-derived VIGS vectors were deployed to induce RNA silencing of cotton GrCLA1, Cloroplastos alterados 1 gene. The albino phenotype caused by silencing GrCLA1 was observed at the seedling stage within 2 weeks after inoculation.

Mediata da Agrobacterium Virus-Induced tacere Assay Gene In Cotone

Cotton (Gossypium hirsutum) is one of the most important crops worldwide. Considerable efforts have been made on molecular breeding of new varieties.  The ...

In Vitro Analysis of PDZ-dependent CFTR Macromolecular Signaling Complexes

Cystic fibrosis transmembrane conductance regulator (CFTR), a chloride channel located primarily at the apical membranes of epithelial cells, plays a crucial role in transepithelial fluid homeostasis1-3. CFTR has been implicated in two major diseases: cystic fibrosis (CF)4 and secretory diarrhea5. In CF, the synthesis or functional activity of the CFTR Cl- channel is reduced. This disorder affects approximately 1 in 2,500 Caucasians in the United States6. Excessive CFTR activity has also been implicated in cases of toxin-induced secretory diarrhea (e.g., by cholera toxin and heat stable E. coli enterotoxin) that stimulates cAMP or cGMP production in the gut7.
Accumulating evidence suggest the existence of physical and functional interactions between CFTR and a growing number of other proteins, including transporters, ion channels, receptors, kinases, phosphatases, signaling molecules, and cytoskeletal elements, and these interactions between CFTR and its binding proteins have been shown to be critically involved in regulating CFTR-mediated transepithelial ion transport in vitro and also in vivo8-19. In this protocol, we focus only on the methods that aid in the study of the interactions between CFTR carboxyl terminal tail, which possesses a protein-binding motif [referred to as PSD95/Dlg1/ZO-1 (PDZ) motif], and a group of scaffold proteins, which contain a specific binding module referred to as PDZ domains. So far, several different PDZ scaffold proteins have been reported to bind to the carboxyl terminal tail of CFTR with various affinities, such as NHERF1, NHERF2, PDZK1, PDZK2, CAL (CFTR-associated ligand), Shank2, and GRASP20-27. The PDZ motif within CFTR that is recognized by PDZ scaffold proteins is the last four amino acids at the C terminus (i.e., 1477-DTRL-1480 in human CFTR)20. Interestingly, CFTR can bind more than one PDZ domain of both NHERFs and PDZK1, albeit with varying affinities22. This multivalency with respect to CFTR binding has been shown to be of functional significance, suggesting that PDZ scaffold proteins may facilitate formation of CFTR macromolecular signaling complexes for specific/selective and efficient signaling in cells16-18.
Multiple biochemical assays have been developed to study CFTR-involving protein interactions, such as co-immunoprecipitation, pull-down assay, pair-wise binding assay, colorimetric pair-wise binding assay, and macromolecular complex assembly assay16-19,28,29. Here we focus on the detailed procedures of assembling a PDZ motif-dependent CFTR-containing macromolecular complex in vitro, which is used extensively by our laboratory to study protein-protein or domain-domain interactions involving CFTR16-19,28,29.

In Vitro Analysis of PDZ-dependent CFTR Macromolecular Signaling Complexes

Cystic fibrosis transmembrane conductance regulator (CFTR), an epithelial chloride channel, has been reported to interact with various proteins and regulate important cellular processes; among them the CFTR PDZ motif-mediated interactions have been well documented. This protocol describes methods we developed to assemble a PDZ-dependent CFTR macromolecular signaling complex in vitro.

L&#39;analisi in vitro dei complessi CFTR PDZ-dipendenti macromolecolari di segnalazione

Cystic fibrosis transmembrane conductance regulator (CFTR), a chloride channel located primarily at the apical membranes of epithelial cells, plays a ...

Culturing Caenorhabditis elegans in Axenic Liquid Media and Creation of Transgenic Worms by Microparticle Bombardment

In this protocol, we present the required materials, and the procedure for making modified&#160;C. elegans&#160;Habituation and Reproduction media (mCeHR). Additionally, the steps for exposing and acclimatizing C. elegans grown on E. coli to axenic liquid media are described. Finally, downstream experiments that utilize axenic C. elegans illustrate the benefits of this procedure. The ability to analyze and determine C. elegans&#160;nutrient requirement was illustrated by growing N2 wild type worms in axenic liquid media with varying heme concentrations. This procedure can be replicated with other nutrients to determine the optimal concentration for worm growth and development or, to determine the toxicological effects of drug treatments. The effects of varied heme concentrations on the growth of wild type worms were determined through qualitative microscopic observation and by quantitating the number of worms that grew in each heme concentration. In addition, the effect of varied nutrient concentrations can be assayed by utilizing worms that express fluorescent sensors that respond to changes in the nutrient of interest. Furthermore, a large number of worms were easily produced for the generation of transgenic C. elegans using microparticle bombardment.

Culturing Caenorhabditis elegans in Axenic Liquid Media and Creation of Transgenic Worms by Microparticle Bombardment

C. elegans is usually grown on solid agar plates or in liquid cultures seeded with E. coli. To prevent bacterial byproducts from confounding toxicological and nutritional studies, we utilized an axenic liquid medium, CeHR, to grow and synchronize a large number of worms for a range of downstream applications.

Culturing<em&gt; Caenorhabditis elegans</em &gt; In axeniche Liquid Media e la creazione di transgeniche Worms da microparticelle Bombardamento

In this protocol, we present the required materials, and the procedure for making modified&#160;C. elegans&#160;Habituation and Reproduction media ...

Open Source High Content Analysis Utilizing Automated Fluorescence Lifetime Imaging Microscopy

We present an open source high content analysis instrument utilizing automated fluorescence lifetime imaging (FLIM) for assaying protein interactions using F&#246;rster resonance energy transfer (FRET) based readouts of fixed or live cells in multiwell plates. This provides a means to screen for cell signaling processes read out using intramolecular FRET biosensors or intermolecular FRET of protein interactions such as oligomerization or heterodimerization, which can be used to identify binding partners. We describe here the functionality of this automated multiwell plate FLIM instrumentation and present exemplar data from our studies of HIV Gag protein oligomerization and a time course of a FRET biosensor in live cells. A detailed description of the practical implementation is then provided with reference to a list of hardware components and a description of the open source data acquisition software written in &#181;Manager. The application of FLIMfit, an open source MATLAB-based client for the OMERO platform, to analyze arrays of multiwell plate FLIM data is also presented. The protocols for imaging fixed and live cells are outlined and a demonstration of an automated multiwell plate FLIM experiment using cells expressing fluorescent protein-based FRET constructs is presented. This is complemented by a walk-through of the data analysis for this specific FLIM FRET data set.

We present an open source high content analysis (HCA) instrument utilizing automated fluorescence lifetime imaging (FLIM) for assaying protein interactions using F&#246;rster resonance energy transfer (FRET) based readouts. Data acquisition for this openFLIM-HCA instrument is controlled by software written in &#181;Manager and data analysis is undertaken in FLIMfit.

Open Source alto contenuto di analisi Utilizzando Automated Fluorescence Lifetime Imaging Microscopy

We present an open source high content analysis instrument utilizing automated fluorescence lifetime imaging (FLIM) for assaying protein interactions ...

Methods to Study Epithelial Transport Protein Function and Expression in Native Intestine and Caco-2 Cells Grown in 3D

The intestinal epithelium has important transport and barrier functions that play key roles in normal physiological functions of the body while providing a barrier to foreign particles. Impaired epithelial transport (ion, nutrient, or drugs) has been associated with many diseases and can have consequences that extend beyond the normal physiological functions of the transporters, such as by influencing epithelial integrity and the gut microbiome. Understanding the function and regulation of transport proteins is critical for the development of improved therapeutic interventions. The biggest challenge in the study of epithelial transport is developing a suitable model system that recapitulates important features of the native intestinal epithelial cells. Several in vitro cell culture models, such as Caco-2, T-84, and HT-29-Cl.19A cells are typically used in epithelial transport research. These cell lines represent a reductionist approach to modeling the epithelium and have been used in many mechanistic studies, including their examination of epithelial-microbial interactions. However, cell monolayers do not accurately reflect cell-cell interactions and the in vivo microenvironment. Cells grown in 3D have shown to be promising models for drug permeability studies. We show that Caco-2 cells in 3D can be used to study epithelial transporters. It is also important that studies in Caco-2 cells are complemented with other models to rule out cell specific effects and to take into account the complexity of the native intestine. Several methods have been previously used to assess the functionality of transporters, such as everted sac and uptake in isolated epithelial cells or in isolated plasma membrane vesicles. Taking into consideration the challenges in the field with respect to models and the measurement of transport function, we demonstrate here a protocol to grow Caco-2 cells in 3D and describe the use of an Ussing chamber as an effective approach to measure serotonin transport, such as in intact polarized intestinal epithelia.

We describe simple methods to study the regulation of intestinal serotonin transporter (SERT) function and expression using an in vitro cell culture model of Caco-2 cells grown in 3D&#160;and an ex vivo model of mouse intestines. These methods are applicable to the study of other epithelial transporters.

Metodi per studiare epiteliale Trasporti funzione delle proteine ​​e di espressione in nativo Intestino e Caco-2 cellule coltivate in 3D

The intestinal epithelium has important transport and barrier functions that play key roles in normal physiological functions of the body while providing ...

Quantifying Spatiotemporal Parameters of Cellular Exocytosis in Micropatterned Cells

Live imaging of the pHluorin tagged Soluble N-ethylmaleimide-sensitive-factor Attachment protein REceptor (v-SNARE) Vesicle-associated membrane protein 7 (VAMP7) by total internal reflection fluorescence microscopy (TIRFM) is a straightforward way to explore secretion from the lysosomal compartment. Taking advantage of cell culture on micropatterned surfaces to normalize cell shape, a variety of statistical tools were employed to perform a spatial analysis of secretory patterns. Using Ripley&#8217;s K function and a statistical test based on the nearest neighbor distance (NND), we confirmed that secretion from lysosomes is not a random process but shows significant clustering. Of note, our analysis revealed that exocytosis events are also clustered in nonadhesion areas, indicating that adhesion molecules are not the only structures that can induce secretory hot spots at the plasma membrane. Still, we found that cell adhesion enhances clustering. In addition to precisely defined adhesive and nonadhesive areas, the circular geometry of these micropatterns allows the use of polar coordinates, simplifying analyses. We used Kernel Density Estimation (KDE) and the cumulative distribution function on polar coordinates of exocytosis events to identify enriched areas of exocytosis. In ring-shaped micropattern cells, clustering occurred at the border between the adhesive and nonadhesive areas. Our analysis illustrates how statistical tools can be employed to investigate spatial distributions of diverse biological processes.

Live imaging of lysosomal exocytosis on micropatterned cells allows a spatial quantification of this process. Morphology normalization using micropatterns is an outstanding tool to uncover general rules about the spatial distribution of cellular processes.

Quantificazione dei parametri Spatiotemporal dell'esocitosi cellulare nelle cellule micromodellate

Live imaging of the pHluorin tagged Soluble N-ethylmaleimide-sensitive-factor Attachment protein REceptor (v-SNARE) Vesicle-associated membrane protein 7 ...

Optimization of Crystal Growth for Neutron Macromolecular Crystallography

The use of neutron macromolecular crystallography (NMX) is expanding rapidly with most structures determined in the last decade thanks to new NMX beamlines having been built and increased availability of structure refinement software. However, the neutron sources currently available for NMX are significantly weaker than equivalent sources for X-ray crystallography. Despite advances in this field, significantly larger crystals will always be required for neutron diffraction studies, particularly with the tendency to study ever-larger macromolecules and complexes. Further improvements in methods and instrumentation suited to growing larger crystals are therefore necessary for the use of NMX to expand.
In this work, we introduce rational strategies and a crystal growth bench (OptiCrys) developed in our laboratory that combines real-time observation through a microscope-mounted video camera with precise automated control of crystallization solutions (e.g., precipitant concentration, pH, additive, temperature). We then demonstrate how this control of temperature and chemical composition facilitates the search for optimal crystallization conditions using model soluble proteins. Thorough knowledge of the crystallization phase diagram is crucial for selecting the starting position and the kinetic path for any crystallization experiment. We show how a rational approach can control the size and number of crystals generated based on knowledge of multidimensional phase diagrams.

Structural studies of biomacromolecules by crystallography require high-quality crystals. Here we demonstrate a protocol that can be used by OptiCrys (a fully automated instrument developed in our lab) and/or microdialysis buttons for growing large high-quality crystals based on knowledge of the crystallization phase diagram.