This research was funded by the Autonomous Province of Trento through core funding of the Ecogenomics group of Fondazione E. Mach.

1. Reagents and media preparation
<ol>
	<li>Prepare 70% ethanol solution: Add 737 mL of 95% technical ethanol to 263 mL of distilled water. Mix thoroughly. 
	NOTE: Prepare 70% ethanol solution on a non-sterile working bench. 
	CAUTION: Ethanol is highly flammable and can cause serious irritation to the eyes. Keep away from flames and heat sources. In case of contact with eyes, rinse with abundant water.</li>
	<li>Prepare 5% bleach solution: Add 5 mL of household bleach (containing ~3.5% of Sodium hypochlorite, NaClO) to 95 mL of sterile distilled water. Add a few drops of non-ionic detergent (e.g., Tween 20) and mix thoroughly. 
	NOTE: Prepare 5% bleach solution inside the laminar hood. 
	CAUTION: Sodium hypochlorite, the active component of bleach, is highly irritating. It is highly corrosive and can cause serious damages to the gastrointestinal tract. In case of contact, rinse immediately with abundant water. In case of ingestion, call the poison control center or a medical physician for treatment advice.</li>
	<li>Prepare half-strength Murashige and Skoog (&#189; MS) medium26.
	<ol>
		<li>Add 2.2 g of MS medium powder (including vitamins) and 10 g of sucrose in 800 mL of distilled water. Adjust the pH of the solution using 1 M KOH and bring the volume up to 1 L using distilled water. Aliquot 500 mL into a 1 L bottle and add 4g of agar to prepare a solid medium. Autoclave the solution.</li>
		<li>After autoclaving, cool down the medium to 50-53 &#176;C in a water bath and pour it into Petri dishes under the laminar flow hood. To prepare the selective medium, add 1000 &#181;L/L of 50 mg/mL kanamycin stock solution (mix 500 mg of Kanamycin sulfate monohydrate in 10 mL of distilled water, filter sterilize and store at -20 &#176;C) to the medium (50-53 &#176;C). Mix well by swirling, and pour into Petri dishes as mentioned before.</li>
	</ol>
	</li>
</ol>
2. Aspirator setup
NOTE: Instrument setup is summarized in Figure 1.
<ol>
	<li>Connect the vacuum pump inlet to one end of a polyethylene (PE) tube of suitable size. Connect the other end of the tube to the outlet of the two-way lid of the decantation bottle. Wrap the tubing&#39;s junction tightly with a sealing film (Table of Materials) to ensure air-tight connection.</li>
	<li>Connect a second PE tube to the inlet (the hole protruding to the inside of the bottle) of the screwcap on the decantation bottle. Fit the other side of the tube to the outlet of an aquarium valve. If necessary, wrap with a sealing film along the junction to eliminate air leakage.</li>
	<li>Just before use, fit a sterile 200 &#181;L pipette tip to the inlet of the aquarium filter under the laminar flow hood.</li>
</ol>
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/62893/62893fig01.jpg" /> 
Figure 1: Schematic drawing of the suction device for high-throughput removal of sterilization liquids. For clarity, the single parts are not drawn to scale. Letter (A) indicates the vacuum pump, (B) the reservoir bottle to collect liquids (ethanol, bleach, or sterile water), (C) the valve to avoid reflux of the liquids, (D) the sterile 200 &#181;L pipette tip, and (E) the 1.5 mL microcentrifuge tube containing seeds and sterilization liquid. Arrows indicate the direction of the airflow. <a href="https://www.jove.com/files/ftp_upload/62893/62893fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
3. High-throughput liquid surface sterilization of seeds
NOTE: The overall procedure and minimal time required for surface sterilization of Arabidopsis thaliana (L.) Heynh wild-type (Col-0) (Arabidopsis) seeds with 96 independent samples are summarized in Figure 2.
<ol>
	<li>Label with a permanent marker two batches of 48 x 1.5 mL microcentrifuge tubes with progressive numbers.</li>
	<li>Add 100-200 Arabidopsis seeds to each of the 96 sterile 1.5 mL microcentrifuge tubes (roughly 1-2 mm above the bottom of the conical end of the tube).</li>
	<li>Aliquot around 1000 &#181;L of 70% ethanol into each tube using a 10 mL sterile serological pipette inside the laminar flow hood (seed batch one, 48 tubes) and carefully close the lids. 
	NOTE: Dispensing the solutions does not need to be extremely accurate, as long as the dispensed volume is several times higher than the volume of seeds. Alternatively, perform this step outside of the laminar hood (non-sterile condition).</li>
	<li>Shake the tubes at an oscillation frequency of 8.0 Hz for at least 3 min in a shaker.</li>
	<li>Remove the adapters from the shaker and transfer them into the basket of a benchtop microcentrifuge.</li>
	<li>Quickly spin down the seeds using the pulse function (present in most benchtop centrifuges) to reach 1880 x g (~15 s). 
	NOTE: Longer time or higher centrifugation forces negatively affects seed germination.</li>
	<li>Transfer the 48 tubes from the adapters to one rack and open all tubes under the laminar flow hood. Avoid contaminations by not touching the part of the lids fitting into the tubes. If lids are too close to each other, divide the tubes into two racks for easier handling.</li>
	<li>Fit a sterile 200 &#181;L yellow tip onto the aquarium valve inlet of the homemade aspirator under the laminar flow hood and switch on the pump.</li>
	<li>Insert the yellow tip just above the level of the seeds to avoid touching the seeds when sucking the liquid. Alternatively, quickly position the tip at the bottom of the tube; if a seed blocks the suction of the liquid, eliminate the yellow tip and insert a new one.</li>
	<li>Aliquot into each tube around 1000 &#181;L of 5% bleach using a 10 mL sterile serological pipette inside the laminar flow hood.</li>
	<li>Tightly close all the lids and put all the tubes back into the shaker adapters. Shake the tubes at an oscillation frequency of 8.0 Hz for at least 3 min in the shaker.</li>
	<li>Quickly spin down the seeds using the pulse function of the benchtop centrifuge for the time necessary to reach 1880 x g (~15 s).</li>
	<li>Fit a new sterile 200 &#181;L yellow tip onto the aquarium valve connected to the vacuum pump under the laminar flow hood, and switch on the pump.</li>
	<li>Insert the yellow tip above the level of the seeds to avoid touching the seeds when sucking the bleach solution.</li>
	<li>Aliquot into each tube around 1000 &#181;L of sterilized H2O using a 10 mL sterile serological pipette in the laminar flow hood. 
	NOTE: Combine the two batches of seeds to minimize the operation time.</li>
	<li>Fit a new sterile 200 &#181;L yellow tip onto the aquarium valve connected to the vacuum pump under the laminar flow hood and switch on the pump.</li>
	<li>Insert the yellow tip just above the level of the seeds to avoid touching the seeds when sucking the H2O.</li>
	<li>Aliquot into each tube around 500 &#181;L of sterilized H2O using a 10 mL sterile serological pipette and close all the lids in the laminar flow hood. The seeds are ready to be sown. If needed, keep the tubes at room temperature for a few hours maximum or at 4 &#176;C overnight.</li>
	<li>Fill the reservoir bottle used to collect liquid with an adequate amount of water and autoclave it. Afterward, discard the liquid into a normal sink. 
	&#8203;NOTE: Autoclave the liquid to kill all the seeds inside the reservoir.</li>
</ol>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/62893/62893fig02.jpg" /> 
Figure 2: Overview of the procedure and minimal time required for surface sterilization of Arabidopsis seeds with 96 independent samples. In the presented experiment, 96 independent samples are handled in two equal-sized batches. The entire procedure is the same for both batches, and they are processed in parallel, but batch two is processed with one step delay compared to batch one. <a href="https://www.jove.com/files/ftp_upload/62893/62893fig02large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
4. Plating and scoring of Arabidopsis on &#189; MS plates
<ol>
	<li>Transfer the seeds and 300-400 &#181;L of sterile H2O into a Petri dish by gentle pipetting with a 1000 &#181;L pipette.</li>
	<li>After transferring 10 tubes, pour into each plate around 1.5-2.0 mL of melted &#189; MS medium without antibiotics. 
	NOTE: Melt in advance and then keep the &#189; MS melted medium in a thermostatic bath set at 50-53 &#176;C to avoid solidification. Ensure that the temperature does not exceed 58 &#176;C to avoid decreasing the germinability of the seeds.</li>
	<li>Quickly swirl the plate to distribute the seeds inside it. Tape the plates on opposite sides.</li>
	<li>Wrap the plates in a plastic or aluminum foil and then place them in a fridge (4 &#176;C) for 3 days in the dark to obtain uniform germination.</li>
	<li>Transfer the plates into a growth chamber set at 23 &#176;C under long-day conditions (16 h light/8 h dark) with a light intensity of 100-120 &#181;mol&#183;m-2&#183;s-1 and 60% relative humidity.</li>
	<li>After two days, score the plants by the presence of radicles. Detect the radicle emergence and green cotyledon formation (full opening of the two cotyledons) to evaluate seed germination.</li>
</ol>
5. Statistical analyses
NOTE: Here, Tukey&#39;s pairwise test was used for statistical analyses.
<ol>
	<li>Consider the P-values below 0.01 as statistically significant. Perform all the experiments at least with five biological replicates.</li>
</ol>

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All authors declare no conflicts of interest.

Sterilization of seeds is the fundamental step for functional studies in Arabidopsis. Although it is frequently carried out for many different purposes, limited studies on high-throughput seed surface sterilization in Arabidopsis are available.
So far, one of the methods with the highest throughput is using chlorine gas generated by mixing bleach with concentrated HCl. Although this method requires limited hands-on time, it uses a gas highly toxic to human beings27. In ...

Arabidopsis is a diploid plant species belonging to the Brassicaceae family. Its relatively short life cycle (two months per generation under long-day growing conditions), small plant size, and self-pollination with the production of hundreds of seeds per plant have made it the first fundamental plant model species1,2. In addition, its genome was fully sequenced3, extensive reverse genetics tools (saturated T-DNA, transposon, and chemically mutagenized populations) are available4,5,6, and effective Agrobacterium-mediated transformation is well-established to obtain sufficient transgenic lines for further downstream work7. Thus, during the last two decades, great advances have been achieved using Arabidopsis as a model species to dissecting diverse aspects of plant biology at the molecular level, including natural, genetic and phenotypic variation8,9.
To functionally characterize genes of interest in Arabidopsis, seed surface sterilization to eliminate fungal and bacterial contaminants is the prerequisite step for many downstream protocols requiring axenic cultures. Genetic transformation for the overexpression10, knock-down (RNA-I11) or knock-out (genome editing12,13) of gene function, subcellular localization14, promoter activity15,16, protein-protein17 and protein-DNA interaction18, to cite only the most common applications, all necessitate a seed surface sterilization step. Thus, despite its relative simplicity, seed surface sterilization plays a fundamental role in many functional analyses.
So far, two major categories of seed surface sterilization methods have been developed based either on gas- or on liquid-phase sterilization19. While the throughput of gas-phase seed surface sterilization is medium to high, using the hazardous reagent chlorine gas as a surface sterilization agent has hindered its wide application. Methods based on liquid-phase sterilization, on the contrary, rely on milder chemicals like ethanol and bleach solutions for surface sterilization, and they are more widely used despite they have an inherently lower throughput than chlorine fumigation. In general, two different methods which use liquid reagents are commonly used. One largely used method is based on washing with ethanol and bleach at different concentrations for different duration of time20,21. Another method is based on the application of bleach only21,22. Both methods are mainly applied for small-scale seed surface sterilization. However, in many experiments, it is necessary to screen many Arabidopsis transgenic lines derived from one transformation15,23 or screen in parallel many transgenic lines generated from different transformations24,25. To the best of our knowledge, no liquid-based method for high-throughput seed surface sterilization has been published, which constitutes, although little-recognized, an important bottleneck for functional genomics approaches. Therefore, developing safe, robust, and high-throughput methods for seed surface sterilization is a necessary and critical step towards the success of the functional characterization of many genes at once.
To this end, in the current study, an improved method for surface sterilization of Arabidopsis seeds is presented. This method is safe, low cost, highly robust, and high-throughput, allowing handling 96 independent lines within one hour from the beginning of seed surface sterilization until the end of seed sowing in Petri dishes. The method demonstrated relies on widely available, basic laboratory instrumentation like a vacuum pump, consumable glassware, and plastic ware. This improved method provides the scientific community a safe, simple, and affordable approach to streamline seed surface sterilization with a throughput adequate to modern functional genomics approaches in Arabidopsis and other non-model plant species.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Aquarium valve</td>
			<td>Amazon</td>
			<td>B074CYC5SD</td>
			<td>Kit including 2 valves and thin-walled tubings. The valve prevents the liquids to go back to the sterile tip</td>
		</tr>
		<tr>
			<td>Arabidopsis Col-0 wild-type seeds</td>
			<td>Nottingham Arabidopsis Stock Center</td>
			<td>N1093</td>
			<td>Wild type seeds (sensitive to kanamycin)</td>
		</tr>
		<tr>
			<td>Arabidopsis transgenic line AdoIspS-79 seeds</td>
			<td>NA</td>
			<td>NA</td>
			<td>Transgenic line overexpressing an isoprene synthase gene from Arundo donax transformed in the Col-0 background, resistant to kanamycin (Li et al. (2017) Mol. Biol. Evol., 34, 2583&#8211;2599). Available on request from the authors</td>
		</tr>
		<tr>
			<td>Microcentrifuge</td>
			<td>Eppendorf</td>
			<td>EP022628188</td>
			<td>Benchtop microcentrifuge used for spinning down the seeds</td>
		</tr>
		<tr>
			<td>Murashige &#38; Skoog medium including vitamins</td>
			<td>Duchefa</td>
			<td>M0222</td>
			<td>Standard medium for plant sterile culture</td>
		</tr>
		<tr>
			<td>Pipette controller</td>
			<td>Brand</td>
			<td>26300</td>
			<td>Used to operate the serological pipette</td>
		</tr>
		<tr>
			<td>Polyethylene tube 1</td>
			<td>Roth</td>
			<td>9591.1</td>
			<td>Tube for connection from vacuum pump to decantation bottle (inner diameter: 7 mm; outer diameter: 9 mm)</td>
		</tr>
		<tr>
			<td>Polyethylene tube 2</td>
			<td>Roth</td>
			<td>9587.1</td>
			<td>Tube for connection from decantation bottle to the aquarium valve&#160; (inner diameter: 5 mm; outer diameter: 7 mm)</td>
		</tr>
		<tr>
			<td>Screw cap with connectors</td>
			<td>Roth</td>
			<td>PY86.1</td>
			<td>2-way dispenser screw cap GL45 in polypropylene for decanting bottle</td>
		</tr>
		<tr>
			<td>Serological pipette</td>
			<td>Brand</td>
			<td>27823</td>
			<td>Graduated glass (reusable) serological pipette. Disposable pipettes can be used instead</td>
		</tr>
		<tr>
			<td>Shakeret al.</td>
			<td>Qiagen</td>
			<td>85300</td>
			<td>TissueLyser II bead mill used normally for tissue homogenization. Without the addition of beads to the tubes it works as shaker.</td>
		</tr>
		<tr>
			<td>Technical ethanol</td>
			<td>ITW Reagents (Nova Chimica Srl)</td>
			<td>212800</td>
			<td>Ethanol 96% v/v partially denatured technical grade</td>
		</tr>
		<tr>
			<td>Tween 20</td>
			<td>Merck Millipore</td>
			<td>655205</td>
			<td>Non-ionic detergent acting as surfactant</td>
		</tr>
		<tr>
			<td>Universal tubing connectors</td>
			<td>Roth</td>
			<td>Y523.1</td>
			<td>Can be used to improve/simplify tubing connections</td>
		</tr>
		<tr>
			<td>Vacuum pump</td>
			<td>Merck Millipore</td>
			<td>WP6222050</td>
			<td>Used for making the suction device</td>
		</tr>
	</tbody>
</table>

high-throughput, robust and highly time-flexible method for surface sterilization of arabidopsis seeds

Arabidopsis is by far the plant model species most widely used for functional studies. The surface sterilization of Arabidopsis seeds is a fundamental step required towards this end. Thus, it is paramount to establish high-throughput Arabidopsis seed surface sterilization methods to handle tens to hundreds of samples (e.g., transgenic lines, ecotypes, or mutants) at once. A seed surface sterilization method based on the efficient elimination of liquid in tubes with a homemade suction device constructed from a common vacuum pump is presented in this study. By dramatically reducing labor-intensive hands-on time with this method handling several hundreds of samples in one day is possible with little effort. Series time-course analyses further indicated a highly flexible time range of surface sterilization by maintaining high germination rates. This method could be easily adapted for surface sterilization of other kinds of small seeds with simple customization of the suction device according to the seed size, and the speed desired to eliminate the liquid.

In order to assess the time required for the entire seed sterilization procedure, the time differences for liquid handling 96 samples in the current protocol were calculated and compared with traditional pipetting methods. The result indicates that the current protocol saves time, cutting the liquid handling time to one-fourth of that with the traditional protocols (Table 1). The table further highlights that the liquid removal time in the current protocol saves more time than that of the traditional met...

Watch this Scientific Journal Video about High-throughput, Robust and Highly Time-flexible Method for Surface Sterilization of Arabidopsis Seeds at JoVE.com

High-throughput, Robust and Highly Time-flexible Method for Surface Sterilization of Arabidopsis Seeds

A high-throughput protocol for the surface sterilization of Arabidopsisthaliana (Arabidopsis) seeds is provided, optimizing the liquid handling steps with a simple suction device constructed with a vacuum pump. Hundreds of seed samples can be surface-sterilized in one day.

Arabidopsis is by far the plant model species most widely used for functional studies. The surface sterilization of Arabidopsis seeds is a fundamental ...

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Biology

3.1K Views.  Fondazione Edmund Mach. A high-throughput protocol for the surface sterilization of Arabidopsisthaliana (Arabidopsis) seeds is provided, optimizing the liquid handling steps with a simple suction device constructed with a vacuum pump. Hundreds of seed samples can be surface-sterilized in one day.

Video: High-throughput, Robust and Highly Time-flexible Method for Surface Sterilization of Arabidopsis Seeds

A high-throughput method to globally study the organelle morphology in S. cerevisiae

High-throughput methods to examine protein localization or organelle morphology is an effective tool for studying protein interactions and can help achieve an comprehensive understanding of molecular pathways. In Saccharomyces cerevisiae, with the development of the non-essential gene deletion array, we can globally study the morphology of different organelles like the endoplasmic reticulum (ER) and the mitochondria using GFP (or variant)-markers in different gene backgrounds. However, incorporating GFP markers in each single mutant individually is a labor-intensive process. Here, we describe a procedure that is routinely used in our laboratory. By using a robotic system to handle high-density yeast arrays and drug selection techniques, we can significantly shorten the time required and improve reproducibility. In brief, we cross a GFP-tagged mitochondrial marker (Apc1-GFP) to a high-density array of 4,672 nonessential gene deletion mutants by robotic replica pinning.  Through diploid selection, sporulation, germination and dual marker selection, we recover both alleles. As a result, each haploid single mutant contains Apc1-GFP incorporated at its genomic locus. Now, we can study the morphology of mitochondria in all non-essential mutant background. Using this high-throughput approach, we can conveniently study and delineate the pathways and genes involved in the inheritance and the formation of organelles in a genome-wide setting.

GFP-fusion proteins are widely used to visualize organelles by confocal microscopy. However, screening for mutations that affect the morphology of organelles generally requires individual mutagenesis and is time consuming. Here, we demonstrate a method to simultaneously incorporate organelle-GFP markers in almost 5,000 non-essential genes in yeast.

High-throughput methods to examine protein localization or organelle morphology is an effective tool for studying protein interactions and can help ...

A High-Throughput Method For Zebrafish Sperm Cryopreservation and In Vitro Fertilization

This is a method for zebrafish sperm cryopreservation that is an adaptation of the Harvey method (Harvey et al., 1982).  We have introduced two changes to the original protocol that both streamline the procedure and increase sample uniformity.  First, we normalize all sperm volumes using freezing media that does not contain the cryoprotectant. Second, cryopreserved sperm are stored in cryovials instead of capillary tubes.  The rates of sperm freezing and thawing (&delta;&deg;C/time) are probably the two most critical variables to control in this procedure.  For this reason, do not substitute different tubes for those specified.  Working in teams of 2 it is possible to freeze the sperm of 100 males per team in ~2 hrs.  Sperm cryopreserved using this protocol has an average of 25% fertility (measured as the number of viable embryos generated in an in vitro fertilization divided by the total number of eggs fertilized) and this percent fertility is stable over many years.

A High-Throughput Method For Zebrafish Sperm Cryopreservation and In Vitro Fertilization

This is a high-throughput sperm cryopreservation protocol for zebrafish. Sperm cryopreserved using this protocol has an average of 25% fertility in subsequent vitro fertilization and is stable over many years.

This is a method for zebrafish sperm cryopreservation that is an adaptation of the Harvey method (Harvey et al., 1982).  We have introduced two changes to ...

A Rapid High-throughput Method for Mapping Ribonucleoproteins (RNPs) on Human pre-mRNA

Sequencing RNAs that co-immunoprecipitate (co-IP) with RNA binding proteins has increased our understanding of splicing by demonstrating that binding location often influences function of a splicing factor.  However, as with any sampling strategy the chance of identifying an RNA bound to a splicing factor is proportional to its cellular abundance.  We have developed a novel in vitro approach for surveying binding specificity on otherwise transient pre-mRNA. This approach utilizes a specifically designed oligonucleotide pool that tiles across introns, exons, splice junctions, or other pre-mRNA.  The pool is subjected to some kind of molecular selection. Here, we demonstrate the method by separating the oligonucleotide into a bound and unbound fraction and utilize a two color array strategy to record the enrichment of each oligonucleotide in the bound fraction. The array data generates high-resolution maps with the ability to identify sequence-specific and structural determinates of ribonucleoprotein (RNP) binding on pre-mRNA.  A unique advantage to this method is its ability to avoid the sampling bias towards mRNA associated with current IP and SELEX techniques, as the pool is specifically designed and synthesized from pre-mRNA sequence. The flexibility of the oligonucleotide pool is another advantage since the experimenter chooses which regions to study and tile across, tailoring the pool to their individual needs.  Using this technique, one can assay the effects of polymorphisms or mutations on binding on a large scale or clone the library into a functional splicing reporter and identify oligonucleotides that are enriched in the included fraction.  This novel in vitro high-resolution mapping scheme provides a unique way to study RNP interactions with transient pre-mRNA species, whose low abundance makes them difficult to study with current in vivo techniques.  



A Rapid High-throughput Method for Mapping Ribonucleoproteins RNPs on Human pre-mRNA

Due to the transient nature of pre-mRNA, it can be difficult to isolate and study in vivo. Here, we present a novel in vitro approach to investigate RNA-protein interactions using a synthetic oligo pool that tiles across selected regions of pre-mRNA.

Sequencing RNAs that co-immunoprecipitate (co-IP) with RNA binding proteins has increased our understanding of splicing by demonstrating that binding ...

Ice-Cap: A Method for Growing Arabidopsis and Tomato Plants in 96-well Plates for High-Throughput Genotyping

It is becoming common for plant scientists to develop projects that require the genotyping of large numbers of plants. The first step in any genotyping project is to collect a tissue sample from each individual plant. The traditional approach to this task is to sample plants one-at-a-time. If one wishes to genotype hundreds or thousands of individuals, however, using this strategy results in a significant bottleneck in the genotyping pipeline. The Ice-Cap method that we describe here provides a high-throughput solution to this challenge by allowing one scientist to collect tissue from several thousand seedlings in a single day 1,2. This level of throughput is made possible by the fact that tissue is harvested from plants 96-at-a-time, rather than one-at-a-time.
The Ice-Cap method provides an integrated platform for performing seedling growth, tissue harvest, and DNA extraction. The basis for Ice-Cap is the growth of seedlings in a stacked pair of 96-well plates. The wells of the upper plate contain plugs of agar growth media on which individual seedlings germinate. The roots grow down through the agar media, exit the upper plate through a hole, and pass into a lower plate containing water. To harvest tissue for DNA extraction, the water in the lower plate containing root tissue is rapidly frozen while the seedlings in the upper plate remain at room temperature. The upper plate is then peeled away from the lower plate, yielding one plate with 96 root tissue samples frozen in ice and one plate with 96 viable seedlings. The technique is named "Ice-Cap" because it uses ice to capture the root tissue. The 96-well plate containing the seedlings can then wrapped in foil and transferred to low temperature. This process suspends further growth of the seedlings, but does not affect their viability. Once genotype analysis has been completed, seedlings with the desired genotype can be transferred from the 96-well plate to soil for further propagation. We have demonstrated the utility of the Ice-Cap method using Arabidopsis thaliana, tomato, and rice seedlings. We expect that the method should also be applicable to other species of plants with seeds small enough to fit into the wells of 96-well plates.

Ice-Cap: A Method for Growing Arabidopsis and Tomato Plants in 96-well Plates for High-Throughput Genotyping

The Ice-Cap method allows one to grow plants in 96-well plates and non-destructively harvest root tissue from each seedling. DNA extracted from this root tissue can be used for genotyping reactions. We have found that Ice-Cap works well for Arabidopsis thaliana, tomato, and rice seedlings.

It is becoming common for plant scientists to develop projects that require the genotyping of large numbers of plants. The first step in any genotyping ...

High-throughput Crystallization of Membrane Proteins Using the Lipidic Bicelle Method

Membrane proteins (MPs) play a critical role in many physiological processes such as pumping specific molecules across the otherwise impermeable membrane bilayer that surrounds all cells and organelles. Alterations in the function of MPs result in many human diseases and disorders; thus, an intricate understanding of their structures remains a critical objective for biological research. However, structure determination of MPs remains a significant challenge often stemming from their hydrophobicity. 
MPs have substantial hydrophobic regions embedded within the bilayer. Detergents are frequently used to solubilize these proteins from the bilayer generating a protein-detergent micelle that can then be manipulated in a similar manner as soluble proteins. Traditionally, crystallization trials proceed using a protein-detergent mixture, but they often resist crystallization or produce crystals of poor quality. These problems arise due to the detergent&prime;s inability to adequately mimic the bilayer resulting in poor stability and heterogeneity. In addition, the detergent shields the hydrophobic surface of the MP reducing the surface area available for crystal contacts. To circumvent these drawbacks MPs can be crystallized in lipidic media, which more closely simulates their endogenous environment, and has recently become a de novo technique for MP crystallization.
Lipidic cubic phase (LCP) is a three-dimensional lipid bilayer penetrated by an interconnected system of aqueous channels1. Although monoolein is the lipid of choice, related lipids such as monopalmitolein and monovaccenin have also been used to make LCP2. MPs are incorporated into the LCP where they diffuse in three dimensions and feed crystal nuclei. A great advantage of the LCP is that the protein remains in a more native environment, but the method has a number of technical disadvantages including high viscosity (requiring specialized apparatuses) and difficulties in crystal visualization and manipulation3,4. Because of these technical difficulties, we utilized another lipidic medium for crystallization-bicelles5,6 (Figure 1). Bicelles are lipid/amphiphile mixtures formed by blending a phosphatidylcholine lipid (DMPC) with an amphiphile (CHAPSO) or a short-chain lipid (DHPC). Within each bicelle disc, the lipid molecules generate a bilayer while the amphiphile molecules line the apolar edges providing beneficial properties of both bilayers and detergents. Importantly, below their transition temperature, protein-bicelle mixtures have a reduced viscosity and are manipulated in a similar manner as detergent-solubilized MPs, making bicelles compatible with crystallization robots. 
Bicelles have been successfully used to crystallize several membrane proteins5,7-11 (Table 1). This growing collection of proteins demonstrates the versatility of bicelles for crystallizing both alpha helical and beta sheet MPs from prokaryotic and eukaryotic sources. Because of these successes and the simplicity of high-throughput implementation, bicelles should be part of every membrane protein crystallographer&prime;s arsenal. In this video, we describe the bicelle methodology and provide a step-by-step protocol for setting up high-throughput crystallization trials of purified MPs using standard robotics.

Bicelles are lipid/amphiphile mixtures that maintain membrane proteins (MPs) within a lipid bilayer but have unique phase behavior that facilitates high-throughput screening by crystallization robots. This technique has successfully produced a number of high-resolution structures from both prokaryotic and eukaryotic sources. This video describes protocols for generating the lipidic bicelle mixture, incorporating MPs into the bicelle mixture, setting up crystallizations trials (manually as well as robotically) and harvesting crystals from the medium.

Membrane proteins (MPs) play a critical role in many physiological processes such as pumping specific molecules across the otherwise impermeable membrane ...

A High-throughput Method for Measurement of Glomerular Filtration Rate in Conscious Mice

The measurement of glomerular filtration rate (GFR) is the gold standard in kidney function assessment. Currently, investigators determine GFR by measuring the level of the endogenous biomarker creatinine or exogenously applied radioactive labeled inulin (3H or 14C). Creatinine has the substantial drawback that proximal tubular secretion accounts for ~50% of total renal creatinine excretion and therefore creatinine is not a reliable GFR marker. Depending on the experiment performed, inulin clearance can be determined by an intravenous single bolus injection or continuous infusion (intravenous or osmotic minipump). Both approaches require the collection of plasma or plasma and urine, respectively. Other drawbacks of radioactive labeled inulin include usage of isotopes, time consuming surgical preparation of the animals, and the requirement of a terminal experiment. Here we describe a method which uses a single bolus injection of fluorescein isothiocyanate-(FITC) labeled inulin and the measurement of its fluorescence in 1-2 &mu;l of diluted plasma. By applying a two-compartment model, with 8 blood collections per mouse, it is possible to measure GFR in up to 24 mice per day using a special work-flow protocol. This method only requires brief isoflurane anesthesia with all the blood samples being collected in a non-restrained and awake mouse. Another advantage is that it is possible to follow mice over a period of several months and treatments (i.e. doing paired experiments with dietary changes or drug applications). We hope that this technique of measuring GFR is useful to other investigators studying mouse kidney function and will replace less accurate methods of estimating kidney function, such as plasma creatinine and blood urea nitrogen.

Measurement of glomerular filtration rate (GFR) is the gold standard for kidney function assessment. Here we describe a high-throughput method which allows the determination of GFR in conscious mice by using a single bolus injection, determination of fluorescein isothiocyanate (FITC)-inulin in plasma and calculation of GFR by a two-phase exponential decay model.

The measurement of  glomerular filtration rate (GFR) is the gold standard in kidney function  assessment. Currently, investigators determine GFR by ...

Efficient and Rapid Isolation of Early-stage Embryos from Arabidopsis thaliana Seeds

In flowering plants, the embryo develops within a nourishing tissue - the endosperm - surrounded by the maternal seed integuments (or seed coat). As a consequence, the isolation of plant embryos at early stages (1 cell to globular stage) is technically challenging due to their relative inaccessibility. Efficient manual dissection at early stages is strongly impaired by the small size of young Arabidopsis seeds and the adhesiveness of the embryo to the surrounding tissues. Here, we describe a method that allows the efficient isolation of young Arabidopsis embryos, yielding up to 40 embryos in 1 hr to 4 hr, depending on the downstream application. Embryos are released into isolation buffer by slightly crushing 250-750 seeds with a plastic pestle in an Eppendorf tube. A glass microcapillary attached to either a standard laboratory pipette (via a rubber tube) or a hydraulically controlled microinjector is used to collect embryos from droplets placed on a multi-well slide on an inverted light microscope. The technical skills required are simple and easily transferable, and the basic setup does not require costly equipment. Collected embryos are suitable for a variety of downstream applications such as RT-PCR, RNA sequencing, DNA methylation analyses, fluorescence in situ hybridization (FISH), immunostaining, and reporter gene assays.

Efficient and Rapid Isolation of Early-stage Embryos from Arabidopsis thaliana Seeds

We report an efficient and simple method to isolate embryos at early stages of development from Arabidopsis thaliana seeds. Up to 40 embryos can be isolated in 1 hr to 4 hr, depending on the downstream application. The procedure is suitable for transcriptome, DNA methylation, reporter gene expression, immunostaining and fluorescence in situ hybridization analyses.

In flowering plants, the embryo develops within a nourishing tissue - the endosperm - surrounded by the maternal seed integuments (or seed coat). As a ...

Highly Efficient Ligation of Small RNA Molecules for MicroRNA Quantitation by High-Throughput Sequencing

MiRNA cloning and high-throughput sequencing, termed miR-Seq, stands alone as a transcriptome-wide approach to quantify miRNAs with single nucleotide resolution. This technique captures miRNAs by attaching 3&#8217; and 5&#8217; oligonucleotide adapters to miRNA molecules and allows de novo miRNA discovery. Coupling with powerful next-generation sequencing platforms, miR-Seq has been instrumental in the study of miRNA biology. However, significant biases introduced by oligonucleotide ligation steps have prevented miR-Seq from being employed as an accurate quantitation tool. Previous studies demonstrate that biases in current miR-Seq methods often lead to inaccurate miRNA quantification with errors up to 1,000-fold for some miRNAs1,2. To resolve these biases imparted by RNA ligation, we have developed a small RNA ligation method that results in ligation efficiencies of over 95% for both 3&#8217; and 5&#8242; ligation steps. Benchmarking this improved library construction method using equimolar or differentially mixed synthetic miRNAs, consistently yields reads numbers with less than two-fold deviation from the expected value. Furthermore, this high-efficiency miR-Seq method permits accurate genome-wide miRNA profiling from in vivo total RNA samples2.

MicroRNAs (miRNAs) are a widely conserved class of regulatory molecules. Here we describe a miRNA cloning method that relies upon two potent ligation steps followed by high-throughput sequencing. Our method permits accurate genome-wide quantitation of miRNAs.

MiRNA cloning and high-throughput sequencing, termed miR-Seq, stands alone as a transcriptome-wide approach to quantify miRNAs with single nucleotide ...

Recovery of Adult Zebrafish Hearts for High-throughput Applications

Use of the zebrafish model system for studying development, regeneration, and disease is expanding toward use of adult hearts for cell dissociation and purification of RNA, DNA, and proteins. All of these applications demand the rapid recovery of significant numbers of zebrafish hearts to avoid gene regulatory, metabolic, and other changes that begin after death. Adult zebrafish hearts are also required for studying heart structure for a variety of mutants and for studying heart regeneration. However, the traditional zebrafish heart dissection is slow and difficult and requires specialized tools, making large-scale dissection of adult zebrafish hearts tedious. Traditional methods also harbor the risk of damaging the heart during the dissection. Here, we describe a method for dissection of adult zebrafish hearts that is fast, reproducible, and preserves heart architecture. Furthermore, this method does not require specialized tools, is painless for the zebrafish, can be performed on fresh or fixed specimens, and can be performed on zebrafish as young as one month old. The approach described expands the use of adult zebrafish for cardiovascular research.

Use of zebrafish for cardiovascular research is expanding towards research on adult hearts. For these applications, quick and simple isolation of cardiac tissues is key to avoid post-mortem changes and to obtain an adequate number of samples. Here, we describe a fast and reproducible method for dissecting adult zebrafish hearts.

Use of the zebrafish model system for studying development, regeneration, and disease is expanding toward use of adult hearts for cell dissociation and ...

High-throughput Screening for Chemical Modulators of Post-transcriptionally Regulated Genes

Both transcriptional and post-transcriptional regulation have a profound impact on genes expression. However, commonly adopted cell-based screening assays focus on transcriptional regulation, being essentially aimed at the identification of promoter-targeting molecules. As a result, post-transcriptional mechanisms are largely uncovered by gene expression targeted drug development. Here we describe a cell-based assay aimed at investigating the role of the 3&#39; untranslated region (3&#8217; UTR) in the modulation of the fate of its mRNA, and at identifying compounds able to modify it. The assay is based on the use of a luciferase reporter construct containing the 3&#8217; UTR of a gene of interest stably integrated into a disease-relevant cell line. The protocol is divided into two parts, with the initial focus on the primary screening aimed at the identification of molecules affecting luciferase activity after 24 hr of treatment. The second part of the protocol describes the counter-screening necessary to discriminate compounds modulating luciferase activity specifically through the 3&#8217; UTR. In addition to the detailed protocol and representative results, we provide important considerations about the assay development and the validation of the hit(s) on the endogenous target. The described cell-based reporter gene assay will allow scientists to identify molecules modulating protein levels via post-transcriptional mechanisms dependent on a 3&#8217; UTR.

Here we describe a cell-based reporter gene assay as a valuable tool to screen chemical libraries for compounds modulating post-transcriptional control mechanisms exerted through 3&#8217; UTR.

Both transcriptional and post-transcriptional regulation have a profound impact on genes expression. However, commonly adopted cell-based screening assays ...