Nous tenons à remercier la Fondation canadienne pour l&#39;innovation, le Fonds de développement des connaissances en Colombie-Britannique et les sciences naturelles et en génie (CRSNG) du Canada pour soutenir les études en cours sur les régions pauvres en oxygène des eaux côtières et océaniques ouverts. MT et SL ont été soutenus par des bourses de la Fondation du Centre TULA financé pour la diversité microbienne et évolution (cmde). MT a également reçu le soutien de la bourse de Deutsche Forschungsgemeinschaft (DFG).

<ol>
	<li>Zaikova, E., Hawley, A., Walsh, D. A., Hallam, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Seawater+sampling+and.">Seawater sampling and.</a> J Vis Exp. , (2009).</li><li>Walsh, D. A., Zaikova, E., Hallam, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Large+volume+(20L+)+filtration+of+coastal+seawater+samples.">Large volume (20L+) filtration of coastal seawater samples.</a> J Vis Exp. 28, (2009).</li><li>Wright, J. J., Lee, S., Zaikova, E., Walsh, D. A., Hallam, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=DNA+Extraction+from+0.22+&#956;M+Sterivex+Filters+and+Cesium+Chloride+Density+Gradient+Centrifugation.">DNA Extraction from 0.22 &#956;M Sterivex Filters and Cesium Chloride Density Gradient Centrifugation.</a> J Vis Exp. 31, 10-3791 (2009).</li><li>Stein, J. L., Marsh, T. L., Wu, K. Y., Shizuya, H., DeLong, E. F. <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+uncultivated+prokaryotes:+isolation+and+analysis+of+a+40-kilobase-pair+genome+fragment+from+a+planktonic+marine+archaeon.">Characterization of uncultivated prokaryotes: isolation and analysis of a 40-kilobase-pair genome fragment from a planktonic marine archaeon.</a> J. Bacteriol. 178, 591-599 (1996).</li><li>B&#233;j&#224;, O., Suzuki, O., Koonin, M. T., Aravind, E. V., Hadd, L., Nguyen, L. P. A., Villacorta, R., Amjadi, M., Garrigues, C., Jovanovich, S. B., Feldman, R. A., DeLong, E. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Construction+and+analysis+of+bacterial+artificial+chromosome+libraries+from+a+marine+microbial+assemblage.">Construction and analysis of bacterial artificial chromosome libraries from a marine microbial assemblage.</a> Environ. Microbiol. 2, 516-529 (2000).</li><li>DeLong, E. F., Preston, C. M., Mincer, T., Rich, V., Hallam, S. J., Frigaard, N. -. U., Martinez, A., Sullivan, M. B., Edwards, R., Brito, B. R., Chisholm, S. W., Karl, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Community+genomics+among+stratified+microbial+assemblages+in+the+Ocean's+interior.">Community genomics among stratified microbial assemblages in the Ocean's interior.</a> Science. 311, 496-503 (2006).</li><li>Hallam, S. J., Putnam, N., Preston, C. M., Detter, J. C., Rokhsar, D., Richardson, P. M., DeLong, E. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reverse+methanogenesis:+testing+the+hypothesis+with+environmental+genomics.">Reverse methanogenesis: testing the hypothesis with environmental genomics.</a> Science. 305, 1457-1462 (2004).</li></ol>

Une procédure est décrite la manière la plus efficace de générer une grande bibliothèque-insert fosmide avec l&#39;ADN génomique provenant d&#39;un échantillon des eaux côtières. En amont d&#39;extraction d&#39;ADN génomique est décrit dans un protocole séparé [3]. Comme la production fosmide-bibliothèque est un multi-processus, le plan d&#39;au moins deux à trois semaines à temps pour toute la procédure, y compris toutes les étapes quatre présentées. L&#39;extraction de...

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		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>Step II</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>CopyControl&trade; Fosmid Library Production Kit</td>
<td>&nbsp;</td>
<td>EPICENTRE</td>
<td>CCFOS110</td>
<td>sufficient to generate 9-10 fosmid libraries</td>
</tr>
<tr>
<td>SeaPlaque Agarose</td>
<td>&nbsp;</td>
<td>Cambrex</td>
<td>50100</td>
<td>&nbsp;</td>
<tr>
<td>stirring hot plate</td>
<td>&nbsp;</td>
<td>Corning</td>
<td>PC-420D</td>
<td>&nbsp;</td>
<tr>
<td>1.0X TAE running buffer</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>CHEF Mapper XA pulsed field electrophoresis system including cooling module and variable speed pump</td>
<td>&nbsp;</td>
<td>Bio-Rad</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>&lambda; DNA-HindIII Digest</td>
<td>&nbsp;</td>
<td>NEB</td>
<td>N3012S</td>
<td>&nbsp;</td>
<tr>
<td>MidRange I PFG Marker</td>
<td>&nbsp;</td>
<td>NEB</td>
<td>N3551S</td>
<td>&nbsp;</td>
<tr>
<td>10,000X SYBR Gold</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>S11494</td>
<td>&nbsp;</td>
<tr>
<td>microwavable plastic wrap</td>
<td>&nbsp;</td>
<td>Saran premium wrap</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Safe Imager transilluminator</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>S37102</td>
<td>&nbsp;</td>
<tr>
<td>GELase Agarose Gel-Digesting Preparation</td>
<td>&nbsp;</td>
<td>EPICENTRE</td>
<td>G09100</td>
<td>&nbsp;</td>
<tr>
<td>scalpel</td>
<td>&nbsp;</td>
<td>Fisher Scientific</td>
<td>08-927-5D</td>
<td>&nbsp;</td>
<tr>
<td>Amicon Ultra-4 Centrifugal Filter Unit with Ultracel-10 membrane</td>
<td>&nbsp;</td>
<td>Millipore</td>
<td>UFC801024</td>
<td>&nbsp;</td>
<tr>
<td>Microcon YM-30 Centrifugal Filter Unit </td>
<td>&nbsp;</td>
<td>Millipore</td>
<td>42410</td>
<td>&nbsp;</td>
<tr>
<td>nuclease free water</td>
<td>&nbsp;</td>
<td>Ambion</td>
<td>AM9932</td>
<td>&nbsp;</td>
<tr>
<td>Quant-iT PicoGreen dsDNA Assay Kit *2000 assays*#</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>P7589</td>
<td>&nbsp;</td>
<tr>
<td>digital dry block heater</td>
<td>&nbsp;</td>
<td>VWR</td>
<td>12621-088</td>
<td>&nbsp;</td>
<tr>
<td>water bath</td>
<td>&nbsp;</td>
<td>VWR</td>
<td>14231-854</td>
<td>&nbsp;</td>
<tr>
<td>centrifuge</td>
<td>&nbsp;</td>
<td>Beckman Coulter</td>
<td>Avanti J-E</td>
<td>&nbsp;</td>
<tr>
<td>centrifuge rotor</td>
<td>&nbsp;</td>
<td>Beckman Coulter</td>
<td>JA 5.3</td>
<td>&nbsp;</td>
<tr>
<td>table top centrifuge</td>
<td>&nbsp;</td>
<td>Eppendorf</td>
<td>5415D</td>
<td>&nbsp;</td>
<tr>
<td>microcentrifuge tubes, 1.7 mL, clear</td>
<td>&nbsp;</td>
<td>Axygen</td>
<td>MCT-175-C</td>
<td>&nbsp;</td>
<tr>
<td>15 mL centrifuge tubes </td>
<td>&nbsp;</td>
<td>Fisher-Corning</td>
<td>430052</td>
<td>&nbsp;</td>
<tr>
<td>Step III</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>LB broth</td>
<td>&nbsp;</td>
<td>Fisher Scientific</td>
<td>BP 1426-2</td>
<td>&nbsp;</td>
<tr>
<td>MgSO4</td>
<td>&nbsp;</td>
<td>Sigma-Aldrich</td>
<td>M2643</td>
<td>&nbsp;</td>
<tr>
<td>phage dilution buffer</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>10 mM Tris-HCl [pH 8.3], 100 mM NaCl, 10 mM MgCl2</td>
</tr>
<tr>
<td>cryogenic vials</td>
<td>&nbsp;</td>
<td>Fisher-Corning</td>
<td>430488</td>
<td>&nbsp;</td>
<tr>
<td>Step IV</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>96 well plate with lid</td>
<td>&nbsp;</td>
<td>Fisher-Corning</td>
<td>CS003370(3370)</td>
<td>&nbsp;</td>
<tr>
<td>384 well plate with lid</td>
<td>&nbsp;</td>
<td>Fisher-Corning</td>
<td>07201157(3680)</td>
<td>&nbsp;</td>
<tr>
<td>Petri dishes 100 O.D. x 15mm H</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>08-757-12</td>
<td>&nbsp;</td>
<tr>
<td>Petri dishes 150 Dia. x 15mmH</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>08-757-14</td>
<td>&nbsp;</td>
<tr>
<td>BD Falcon BioDish XL 245 X 245 mm</td>
<td>&nbsp;</td>
<td>VWR</td>
<td>CABD351040</td>
<td>&nbsp;</td>
<tr>
<td>glycerol</td>
<td>&nbsp;</td>
<td>Sigma-Aldrich</td>
<td>G5516</td>
<td>&nbsp;</td>
<tr>
<td>chloramphenicol</td>
<td>&nbsp;</td>
<td>Sigma-Aldrich</td>
<td>C0378</td>
<td>&nbsp;</td>
<tr>
<td>LB broth</td>
<td>&nbsp;</td>
<td>Fisher Scientific</td>
<td>BP 1426-2</td>
<td>&nbsp;</td>
<tr>
<td>Difco Agar</td>
<td>&nbsp;</td>
<td>BD</td>
<td>214530</td>
<td>&nbsp;</td>
<tr>
<td>glass beads</td>
<td>&nbsp;</td>
<td>Fisher Scientific</td>
<td>10-310-1</td>
<td>&nbsp;</td>
<tr>
<td>QFill3</td>
<td>&nbsp;</td>
<td>Genetix</td>
<td>X3050</td>
<td>&nbsp;</td>
<tr>
<td>Bleach</td>
<td>&nbsp;</td>
<td>Javex</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Ethanol</td>
<td>&nbsp;</td>
<td>Sigma-Aldrich</td>
<td>E7023</td>
<td>&nbsp;</td>
<tr>
<td>15 mL centrifuge tubes</td>
<td>&nbsp;</td>
<td>Fisher-Corning</td>
<td>430052</td>
<td>&nbsp;</td>
<tr>
<td>QPix colony picker</td>
<td>&nbsp;</td>
<td>Genetix</td>
<td>QPix2</td>
<td>&nbsp;</td>
<tr>
<td>picking head (E. coli) </td>
<td>&nbsp;</td>
<td>Genetix</td>
<td>X4006</td>
<td>&nbsp;</td>		</tbody>
		</table>
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large insert environmental genomic library production

La grande majorité des microbes dans la nature restent actuellement inaccessibles aux méthodes de culture traditionnelles. Au cours des dix dernières années, la culture indépendante génomique environnementale (<em&gt; À savoir</em&gt; Métagénomique) approches ont émergé, permettant aux chercheurs de combler cette lacune de culture en capturant le contenu génétique des populations autochtones des communautés microbiennes directement à partir de l&#39;environnement. À cette fin, banques d&#39;ADN génomique sont construits en utilisant la norme mais astucieuse des techniques de clonage en laboratoire. Nous décrivons ici la construction d&#39;une bibliothèque génomique insérer des grandes environnement fosmide avec l&#39;ADN provenant du continuum profondeur verticale d&#39;un fjord saisonnière hypoxiques. Ce protocole est directement liée à une série de protocoles reliés y compris l&#39;échantillonnage des eaux côtières marines [1], la filtration grand volume de biomasse microbienne [2] et une extraction d&#39;ADN et protocole de purification [3]. A l&#39;origine, de haute qualité est l&#39;ADN génomique fin réparé avec la création de la 5-phosphorylés des extrémités franches. Fin réparé ADN est soumis à une électrophorèse en champ pulsé (PFGE) pour la sélection de taille et d&#39;extraction de gel est effectuée pour récupérer des fragments d&#39;ADN entre 30 et 60 mille paires de base (Ko) de longueur. L&#39;ADN est purifié Taille sélectionnés loin de la matrice du gel PFGE et ligaturé au traité à la phosphatase à bout émoussé fosmide CopyControl pCC1 vecteur (EPICENTRE<a href="http://www.epibio.com/item.asp?ID=385"&gt; Http://www.epibio.com/item.asp?ID=385</a&gt;). Concatémères linéaire de pCC1 et insert d&#39;ADN sont ensuite emballés dans des headfull des particules de phage lambda par terminase, avec une infection ultérieure du phage résistant<em&gt; E. coli</em&gt; Cellules. Réussir clones transduits sont récupérés sur des plaques d&#39;agar LB sous sélection antibiotique et archivés dans le format de 384 puits plaque à l&#39;aide d&#39;une colonie automatisé picking robot (Qpix2, GENETIX). Le protocole actuel s&#39;inspire de diverses sources, y compris le kit CopyControl fosmide production bibliothèque d&#39;Epicentre et les oeuvres publiées de multiples groupes de recherche [4-7]. Chaque étape est présentée avec les meilleures pratiques à l&#39;esprit. Autant que possible nous mettons en évidence les subtilités de l&#39;exécution afin d&#39;améliorer la qualité et l&#39;efficacité globales de la production de la bibliothèque. L&#39;ensemble du processus de production et la cueillette des bibliothèques fosmide colonie automatisé prend au moins 7-10 jours comme il ya de nombreuses étapes d&#39;incubation inclus. Cependant, il existe plusieurs points d&#39;arrêt possibles qui sont mentionnés dans le protocole.

Watch this Scientific Journal Video about Large Insert Environmental Genomic Library Production at JoVE.com

Large Insert Environmental Genomic Library Production

Construction d&#39;une bibliothèque fosmide avec l&#39;ADN génomique environnementale isolé du continuum profondeur verticale d&#39;un fjord saisonnière hypoxiques est décrite. La bibliothèque clone résultant est capté dans les plaques 384 puits et archivées pour le séquençage et l&#39;aval de criblage fonctionnel par l&#39;application d&#39;un système de picking colonie automatisés.

Grand Insérer production bibliothèque génomique de l&#39;environnement

The vast majority of microbes in nature currently remain inaccessible to traditional cultivation methods. Over the past decade, culture-independent ...

large-insert-environmental-genomic-library-production

Research

JoVE Journal

Biology

15.8K vues.  University of British Columbia - UBC. Construction d'une bibliothèque fosmide avec l'ADN génomique environnementale isolé du continuum profondeur verticale d'un fjord saisonnière hypoxiques est décrite. La bibliothèque clone résultant est capté dans les plaques 384 puits et archivées pour le séquençage et l'aval de criblage fonctionnel par l'application d'un système de picking colonie automatisés.

Vidéo: Large Insert Environmental Genomic Library Production

Large-Scale Screens of Metagenomic Libraries

Metagenomic libraries archive large fragments of contiguous genomic sequences from microorganisms without requiring prior cultivation. Generating a streamlined procedure for creating and screening metagenomic libraries is therefore useful for efficient high-throughput investigations into the genetic and metabolic properties of uncultured microbial assemblages. Here, key protocols are presented on video, which we propose is the most useful format for accurately describing a long process that alternately depends on robotic instrumentation and (human) manual interventions. First, we employed robotics to spot library clones onto high-density macroarray membranes, each of which can contain duplicate colonies from twenty-four 384-well library plates. Automation is essential for this procedure not only for accuracy and speed, but also due to the miniaturization of scale required to fit the large number of library clones into highly dense spatial arrangements. Once generated, we next demonstrated how the macroarray membranes can be screened for genes of interest using modified versions of standard protocols for probe labeling, membrane hybridization, and signal detection. We complemented the visual demonstration of these procedures with detailed written descriptions of the steps involved and the materials required, all of which are available online alongside the video.

Grands écrans des banques métagénomiques

Metagenomic libraries archive large fragments of contiguous genomic sequences from microorganisms without requiring prior cultivation.  Generating a ...

Recherche

Biologie

Isolation of Genomic DNA from Mouse Tails

Isolement de l&#39;ADN génomique de souris Tails

Technical Demonstration of Whole Genome Array Comparative Genomic Hybridization

Array comparative genomic hybridization (array CGH) is a method for detecting gains and losses of DNA segments or gene dosage in the genome 1. Recent advances in this technology have enabled high resolution comparison of whole genomes for the identification of genetic alterations in cancer and other genetic diseases 2. The Sub-Megabase Resolution Tiling-set array (or SMRT) array is comprised of a set of approximately thirty thousand overlapping bacterial artificial chromosome (BAC) clones that span the human genome in ~100 kilobase pair (kb) segments 2. These BAC targets are individually synthesized and spotted in duplicate on a single glass slide 2-4. Array CGH is based on the principle of competitive hybridization. Sample and reference DNA are differentially labeled with Cyanine-3 and Cyanine-5 fluorescent dyes, and co-hybridized to the array. After an incubation period the unbound samples are washed from the slide and the array is imaged. A freely available custom software package called SeeGH (www.flintbox.ca) is used to process the large volume of data collected - a single experiment generates 53,892 data points. SeeGH visualizes the log2 signal intensity ratio between the 2 samples at each BAC target which is vertically aligned with chromosomal position 5,6. The SMRT array can detect alterations as small as 50 kb in size 7. The SMRT array can detect a variety of DNA rearrangement events including DNA gains, losses, amplifications and homozygous deletions. A unique advantage of the SMRT array is that one can use DNA isolated from formalin fixed paraffin embedded samples. When combined with the low input requirements of unamplified DNA (25-100ng) this allows profiling of precious samples such as those produced by microdissection 7,8. This is attributed to the large size of each BAC hybridization target that allows the binding of sufficient labeled samples to produce signals for detection. Another advantage of this platform is the tolerance of tissue heterogeneity, decreasing the need for tedious tissue microdissection 8. This video protocol is a step-by-step tutorial from labeling the input DNA through to signal acquisition for the whole genome tiling path SMRT array.

This video is a technical demonstration of the hybridization protocol for whole genome tiling path array CGH, which scans the entire human genome using only 25-100 ng of DNA that can be isolated from a variety of sources, including archival formalin fixed material.

Démonstration technique de l&#39;hybridation tableau Whole Genome génomique comparative

Array comparative genomic hybridization (array CGH) is a method for detecting gains and losses of DNA segments or gene dosage in the genome 1.  Recent ...

Fabrication and Operation of an Oxygen Insert for Adherent Cellular Cultures 

Oxygen is a key modulator of many cellular pathways, but current devices permitting in vitro oxygen modulation fail to meet the needs of biomedical research. The hypoxic chamber offers a simple system to control oxygenation in standard culture vessels, but lacks precise temporal and spatial control over the oxygen concentration at the cell surface, preventing its application in studying a variety of physiological phenomena. Other systems have improved upon the hypoxic chamber, but require specialized knowledge and equipment for their operation, making them intimidating for the average researcher. A microfabricated insert for multiwell plates has been developed to more effectively control the temporal and spatial oxygen concentration to better model physiological phenomena found in vivo. The platform consists of a polydimethylsiloxane insert that nests into a standard multiwell plate and serves as a passive microfluidic gas network with a gas-permeable membrane aimed to modulate oxygen delivery to adherent cells. The device is simple to use and is connected to gas cylinders that provide the pressure to introduce the desired oxygen concentration into the platform. Fabrication involves a combination of standard SU-8 photolithography, replica molding, and defined PDMS spinning on a silicon wafer. The components of the device are bonded after surface treatment using a hand-held plasma system. Validation is accomplished with a planar fluorescent oxygen sensor. Equilibration time is on the order of minutes and a wide variety of oxygen profiles can be attained based on the device design, such as the cyclic profile achieved in this study, and even oxygen gradients to mimic those found in vivo. The device can be sterilized for cell culture using common methods without loss of function. The device's applicability to studying the in vitro wound healing response will be demonstrated.

Fabrication and Operation of an Oxygen Insert for Adherent Cellular Cultures

Fabrication and validation of an add-on platform that offers enhanced control over the spatial and temporal oxygenation in a 6-well plate. The device is adaptable to a number of culture systems and can be used to investigate the effects of oxygen on wound healing.

Fabrication et fonctionnement d&#39;un insert d&#39;oxygène pour les adhérents des cultures cellulaires

Oxygen is a key modulator of many cellular pathways, but current devices permitting in vitro oxygen modulation fail to meet the needs of biomedical ...

Genomic MRI - a Public Resource for Studying Sequence Patterns within Genomic DNA

Non-coding genomic regions in complex eukaryotes, including intergenic areas, introns, and untranslated segments of exons, are profoundly non-random in their nucleotide composition and consist of a complex mosaic of sequence patterns. These patterns include so-called Mid-Range Inhomogeneity (MRI) regions -- sequences 30-10000 nucleotides in length that are enriched by a particular base or combination of bases (e.g. (G+T)-rich, purine-rich, etc.). MRI regions are associated with unusual (non-B-form) DNA structures that are often involved in regulation of gene expression, recombination, and other genetic processes (Fedorova &amp; Fedorov 2010). The existence of a strong fixation bias within MRI regions against mutations that tend to reduce their sequence inhomogeneity additionally supports the functionality and importance of these genomic sequences (Prakash et al. 2009).
Here we demonstrate a freely available Internet resource -- the Genomic MRI program package -- designed for computational analysis of genomic sequences in order to find and characterize various MRI patterns within them (Bechtel et al. 2008). This package also allows generation of randomized sequences with various properties and level of correspondence to the natural input DNA sequences. The main goal of this resource is to facilitate examination of vast regions of non-coding DNA that are still scarcely investigated and await thorough exploration and recognition.

We present a public computational web site for the analysis of genomic sequences. It detects DNA sequence patterns with various non-random nucleotide compositions. This resource also generates randomized sequences with diverse levels of complexity.

Genomic IRM - une ressource publique pour l&#39;étude des schémas de séquence dans l&#39;ADN génomique

Non-coding genomic regions in complex eukaryotes, including intergenic areas, introns, and untranslated segments of exons, are profoundly non-random in ...

Competitive Genomic Screens of Barcoded Yeast Libraries

By virtue of advances in next generation sequencing technologies, we have access to new genome sequences almost daily. The tempo of these advances is accelerating, promising greater depth and breadth. In light of these extraordinary advances, the need for fast, parallel methods to define gene function becomes ever more important. Collections of genome-wide deletion mutants in yeasts and E. coli have served as workhorses for functional characterization of gene function, but this approach is not scalable, current gene-deletion approaches require each of the thousands of genes that comprise a genome to be deleted and verified. Only after this work is complete can we pursue high-throughput phenotyping. Over the past decade, our laboratory has refined a portfolio of competitive, miniaturized, high-throughput genome-wide assays that can be performed in parallel. This parallelization is possible because of the inclusion of DNA 'tags', or 'barcodes,' into each mutant, with the barcode serving as a proxy for the mutation and one can measure the barcode abundance to assess mutant fitness. In this study, we seek to fill the gap between DNA sequence and barcoded mutant collections. To accomplish this we introduce a combined transposon disruption-barcoding approach that opens up parallel barcode assays to newly sequenced, but poorly characterized microbes. To illustrate this approach we present a new Candida albicans barcoded disruption collection and describe how both microarray-based and next generation sequencing-based platforms can be used to collect 10,000 - 1,000,000 gene-gene and drug-gene interactions in a single experiment.

We have developed comprehensive, unbiased genome-wide screens to understand gene-drug and gene-environment interactions. Methods for screening these mutant collections are presented.

Écrans concurrentiel des bibliothèques génomiques de levure Barcoded

By virtue of advances in next generation sequencing technologies, we have access to new genome sequences almost daily.  The tempo of these advances is ...

Genomic Transformation of the Picoeukaryote Ostreococcus tauri

Common problems hindering rapid progress in Plant Sciences include cellular, tissue and whole organism complexity, and notably the high level of genomic redundancy affecting simple genetics in higher plants. The novel model organism Ostreococcus tauri is the smallest free-living eukaryote known to date, and possesses a greatly reduced genome size and cellular complexity1,2, manifested by the presence of just one of most organelles (mitochondrion, chloroplast, golgi stack) per cell, and a genome containing only ~8000 genes. Furthermore, the combination of unicellularity and easy culture provides a platform amenable to chemical biology approaches. Recently, Ostreococcus has been successfully employed to study basic mechanisms underlying circadian timekeeping3-6. Results from this model organism have impacted not only plant science, but also mammalian biology7. This example highlights how rapid experimentation in a simple eukaryote from the green lineage can accelerate research in more complex organisms by generating testable hypotheses using methods technically feasible only in this background of reduced complexity. Knowledge of a genome and the possibility to modify genes are essential tools in any model species. Genomic1, Transcriptomic8, and Proteomic9 information for this species is freely available, whereas the previously reported methods6,10 to genetically transform Ostreococcus are known to few laboratories worldwide.
In this article, the experimental methods to genetically transform this novel model organism with an overexpression construct by means of electroporation are outlined in detail, as well as the method of inclusion of transformed cells in low percentage agarose to allow selection of transformed lines originating from a single transformed cell. Following the successful application of Ostreococcus to circadian research, growing interest in Ostreococcus can be expected from diverse research areas within and outside plant sciences, including biotechnological areas. Researchers from a broad range of biological and medical sciences that work on conserved biochemical pathways may consider pursuing research in Ostreococcus, free from the genomic and organismal complexity of larger model species.

Genomic Transformation of the Picoeukaryote Ostreococcus tauri

This article describes genetic transformation of the unicellular marine alga Ostreococcus tauri by electroporation. This eukaryotic organism is an effective model platform for higher plants, possesing greatly reduced genomic and cellular complexity and being readily amenable to both cell culture and chemical biology.

Transformation génomique de la Picoeukaryote<em&gt; Ostreococcus tauri</em

Common problems hindering rapid progress in Plant Sciences include cellular, tissue and whole organism complexity, and notably the high level of genomic ...

Array Comparative Genomic Hybridization (Array CGH) for Detection of Genomic Copy Number Variants

Array CGH for the detection of genomic copy number variants has replaced G-banded karyotype analysis. This paper describes the technology and its application in a clinical diagnostic service laboratory. DNA extracted from a patient&#8217;s sample (blood, saliva or other tissue types) is labeled with a fluorochrome (either cyanine 5 or cyanine 3). A reference DNA sample is labeled with the opposite fluorochrome. There follows a cleanup step to remove unincorporated nucleotides before the labeled DNAs are mixed and resuspended in a hybridization buffer and applied to an array comprising ~60,000 oligonucleotide probes from loci across the genome, with high probe density in clinically important areas. Following hybridization, the arrays are washed, then scanned and the resulting images are analyzed to measure the red and green fluorescence for each probe. Software is used to assess the quality of each probe measurement, calculate the ratio of red to green fluorescence and detect potential copy number variants.

Array Comparative Genomic Hybridization Array CGH for Detection of Genomic Copy Number Variants

Array CGH for the detection of genomic copy number variants has replaced G-banded karyotype analysis. This paper describes the technology and its application in a diagnostic service laboratory.

Tableau hybridation génomique comparative (CGH array) pour la détection des variantes génomiques du nombre de copies

Array CGH for the detection of genomic copy number variants has replaced G-banded karyotype analysis. This paper describes the technology and its ...

A Two-Step Strategy that Combines Epigenetic Modification and Biomechanical Cues to Generate Mammalian Pluripotent Cells

Cell phenotype can be reversed or modified with different methods, with advantages and limitations that are specific for each technique. Here we describe a new strategy that combines the use of chemical epigenetic erasing with mechanosensing-related cues, to generate mammalian pluripotent cells. Two main steps are required. In the first step, adult mature (terminally differentiated) cells are exposed to the epigenetic eraser 5-aza-cytidine to drive them into a pluripotent state. This part of the protocol was developed, based on the increasing understanding of the epigenetic mechanisms controlling cell fate and differentiation, and involves the use of the epigenetic modifier to erase cell differentiated state and then drive into a transient high plasticity window.
In the second step, erased cells are encapsulated in polytetrafluoroethylene (PTFE) micro-bioreactors, also known as Liquid Marbles, to promote 3D cell rearrangement to extend and stably maintain the acquired high plasticity. PTFE is a non-reactive hydrophobic synthetic compound and its use permits the creation of a cellular microenvironment, which cannot be achieved in traditional 2D culture systems. This system encourages and boosts the maintenance of pluripotency though bio-mechanosensing-related cues.
The technical procedures described here are simple strategies to allow for the induction and maintenance of a high plasticity state in adult somatic cells. The protocol allowed the derivation of high plasticity cells in all mammalian species tested. Since it does not involve the use of gene transfection and is free of viral vectors, it may represent a notable technological advance for translational medicine applications. Furthermore, the micro-bioreactor system provides a notable advancement in stem cell organoid technology by in vitro re-creating a specific micro-environment that allows for the long-term culture of high plasticity cells, namely as ESCs, iPSCs, epigenetically erased cells and MSCs.

We here present a method that combines the use of chemical epigenetic erasing with mechanosensing-related cues to efficiently generate mammalian pluripotent cells, without the need of gene transfection or retroviral vectors. This strategy is, therefore, promising for translational medicine and represents a notable advancement in stem cell organoid technology.

Une stratégie en deux étapes qui combine la modification épigénétique et les indices biomécaniques pour générer des cellules pluripotentes de mammifères

Cell phenotype can be reversed or modified with different methods, with advantages and limitations that are specific for each technique. Here we describe ...

A Robust Method for the Large-Scale Production of Spheroids for High-Content Screening and Analysis Applications

High-content screening (HCS) and high-content analysis (HCA) are technologies that provide researchers with the ability to extract large-scale quantitative phenotypic measurements from cells. This approach has proved powerful for deepening our understanding of a wide range of both fundamental and applied events in cell biology. To date, the majority of applications for this technology have relied on the use of cells grown in monolayers, although it is increasingly realized that such models do not recapitulate many of the interactions and processes that occur in tissues. As such, there has been an emergence in the development and use of 3-dimensional (3D) cell assemblies, such as spheroids and organoids. Although these 3D models are particularly powerful in the context of cancer biology and drug delivery studies, their production and analysis in a reproducible manner suitable for HCS and HCA present a number of challenges. The protocol detailed here describes a method for the generation of multicellular tumor spheroids (MCTS), and demonstrates that it can be applied to three different cell lines in a manner that is compatible with HCS and HCA. The method facilitates the production of several hundred spheroids per well, providing the specific advantage that when used in a screening regime, data can be obtained from several hundred structures per well, all treated in an identical manner. Examples are also provided, which detail how to process the spheroids for high-resolution fluorescence imaging and how HCA can extract quantitative features at both the spheroid level as well as from individual cells within each spheroid. This protocol could easily be applied to answer a wide range of important questions in cell biology.

This protocol details a method for the production of three different types of spheroids in a manner that makes them suitable for large-scale high-content screening and analysis. In addition, examples are presented showing how they can be analyzed at spheroid and individual cell levels.