Name: a 3-dimensional (3d)-printed template for high throughput zebrafish embryo arraying
Uploaded: 2018-06-01T15:00:00
Description: Watch this Scientific Journal Video about A 3-dimensional 3D-printed Template for High Throughput Zebrafish Embryo Arraying at JoVE.com

This work was supported by the &#34;1000plan Youth&#34; program, the Startup Funds from Tongji University, and NSFC Grant# 21607115 and 21777116 (Lin).

1. Design and Fabrication of a Zebrafish Embryos Arraying Template
<ol>
	<li>Design the arraying template with a 12 by 8, 96-well layout that fits a standard 96-well plate. Use the dimensions listed in Figure 1A for the upper embryo entrapment chamber (see also the Supplemental File).
	<ol>
		<li>Use the dimensions shown in Figure 1B and 1D for the entrapment well.</li>
		<li>Use the dimensions in Figure 1...

<ol>
	<li>Howe, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+zebrafish+reference+genome+sequence+and+its+relationship+to+the+human+genome.">The zebrafish reference genome sequence and its relationship to the human genome.</a> Nature. 496 (7446), 498-503 (2013).</li><li>Leslie, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zebrafish+larvae+could+help+to+personalize+cancer+treatments.">Zebrafish larvae could help to personalize cancer treatments.</a> Science. 357 (6353), 745-745 (2017).</li><li>Lin, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Understanding+the+Transformation,+Speciation,+and+Hazard+Potential+of+Copper+Particles+in+a+Model+Septic+Tank+System+Using+Zebrafish+to+Monitor+the+Effluent.">Understanding the Transformation, Speciation, and Hazard Potential of Copper Particles in a Model Septic Tank System Using Zebrafish to Monitor the Effluent.</a> ACS Nano. 9 (2), 2038-2048 (2015).</li><li>Lin, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aspect+ratio+plays+a+role+in+the+hazard+potential+of+ceo2+nanoparticles+in+mouse+lung+and+zebrafish+gastrointestinal+tract.">Aspect ratio plays a role in the hazard potential of ceo2 nanoparticles in mouse lung and zebrafish gastrointestinal tract.</a> ACS Nano. 8 (5), 4450-4464 (2014).</li><li>Baraban, S. C., Dinday, M. T., Hortopan, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drug+screening+in+Scn1a+zebrafish+mutant+identifies+clemizole+as+a+potential+Dravet+syndrome+treatment.">Drug screening in Scn1a zebrafish mutant identifies clemizole as a potential Dravet syndrome treatment.</a> Nature Communications. 4, (2013).</li><li>Lin, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High+content+screening+in+zebrafish+speeds+up+hazard+ranking+of+transition+metal+oxide+nanoparticles.">High content screening in zebrafish speeds up hazard ranking of transition metal oxide nanoparticles.</a> ACS Nano. 5 (9), 7284-7295 (2011).</li><li>Kuipers, J., Kalicharan, R. D., Wolters, A. H. G., van Ham, T. J., Giepmans, B. N. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Large-scale+Scanning+Transmission+electron+microscopy+(nanotomy)+of+healthy+and+injured+zebrafish+brain.">Large-scale Scanning Transmission electron microscopy (nanotomy) of healthy and injured zebrafish brain.</a> Journal of Visualized Experiments. (111), (2016).</li><li>Liu, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Automated+Phenotype+Recognition+for+Zebrafish+Embryo+Based+In+vivo+High+Throughput+Toxicity+Screening+of+Engineered+Nano-Materials.">Automated Phenotype Recognition for Zebrafish Embryo Based In vivo High Throughput Toxicity Screening of Engineered Nano-Materials.</a> PLoS One. 7 (4), (2012).</li><li>Tu, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Automatic+Categorization+and+Scoring+of+Solid,+Part-Solid+and+Non-Solid+Pulmonary+Nodules.">Automatic Categorization and Scoring of Solid, Part-Solid and Non-Solid Pulmonary Nodules.</a> in CT Images with Convolutional Neural Network. Scientific Reports. 7, 8533 (2017).</li><li>Mandrell, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Automated+zebrafish+chorion+removal+and+single+embryo+placement:+optimizing+throughput+of+zebrafish+developmental+toxicity+screens.">Automated zebrafish chorion removal and single embryo placement: optimizing throughput of zebrafish developmental toxicity screens.</a> Journal of Laboratory Automation. 17 (1), 66-74 (2012).</li><li>Lin, S., Zhao, Y., Nel, A. E., Lin, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zebrafish:+An+in+vivo+model+for+nano+EHS+studies.">Zebrafish: An in vivo model for nano EHS studies.</a> Small. 9 (9-10), 1608-1618 (2013).</li></ol>

There are two critical steps in this protocol that require close attention for a successful implementation of 3D-printed template for arraying zebrafish embryos.
The most important factor on the design of the arraying template is the entrapment well. To makes sure there is only one embryo trapped in each well, one should pay close attention to the diameter and the depth of the entrapment well, and the diameter of the through hole. The recommended diameter is within 1.5 to 2 times of the diamet...

As a popular model organism, zebrafish is widely used in the fields of medicine and toxicology1,2,3,4. Compared to in vitro platforms, zebrafish offer much greater biological complexities that one or two cell types could not offer. Besides being a whole organism model, the zebrafish&#39;s large fecundity, rapid and simultaneous embryonic development, and high organ translucency have given this model unique advantages to be used for large scale toxicity or drugs/compound screening5. The hundreds of embryos produced by one pair of adult zebrafish each week surpass any other whole animal models and have made it suitable for high throughput screening.
A typical screening procedure using zebrafish involves a significant amount of manual work, such as adult zebrafish spawning, embryo selection, and arraying embryos into suitable containers where they are subjected to exposure through water immersion. The development of the embryos is monitored and observable endpoints such as mortality, hatchability and abnormality are often evaluated manually and used as the preliminary identifications of the toxicity of chemicals or indications of the effectiveness of drugs or compounds. To speed up the screening procedure, approaches such as automated imaging and computer-assisted image analysis have been explored previously. For example, microscopes with high content imaging capabilities have been adapted to perform automated bright-field or fluorescence imaging on zebrafish embryos at various developmental stages from 96/384 well plates6. Microfluidic devices coupled with microscopes were used to position zebrafish larvae through current manipulation for imaging of brain neurons7. These approaches could significantly improve the efficiency of image acquisitions compared to traditional manual operation. Moreover, with large number of images being generated, image analysis tools have also been developed to speed up the data processing, as demonstrated by Liu et al. and Tu et al.8,9.
As the throughput level of imaging and image analysis increases, it became clear that the rate-limiting step for screening lies in the process of preparing zebrafish embryos for exposure, which typically means arraying them into 96- or 384-well plates. To solve this bottleneck step, vision-guided robotics were developed by Mandrell et al.10 and us11 previously to replace manual handling but the instruments were rather sophisticated and there is a deep learning curve to implement such techniques. Therefore, to provide an easy-to-use approach becomes one important factor to further improve the throughput level of zebrafish screening and is the main objective of this work.
In this work, we designed and fabricated an embryo arraying template by 3D printing. Such an arraying template was designed to entrap zebrafish embryo into wells that fit with a standard 96-well plate. Instead of selecting embryos and arraying them into individual well one by one, one could perform embryo entrapment and array all 96 embryos into a multiwall plate at once. Using this template and the following protocol, one could significantly increase the efficiency of arraying embryos into multiwall plates, which would in term boost the screening capacity at least tenfold, compared to manual operation. The protocol described below includes an overall design for the arraying template, zebrafish spawning, embryo collection, and arraying. Figure 1 shows the overall design of the arraying template. Figure 2 shows an overview of the step-by-step protocol on using the template described in Parts 3 and 4.

<table border="0" cellpadding="0" cellspacing="0" width="1557">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:475px;">Zebrafish Facility</td>
			<td style="width:425px;">Shanghai Haisheng Biotech Co., Ltd.</td>
			<td style="width:229px;">Z-A-S5</td>
			<td style="width:429px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:475px;">Mating box</td>
			<td style="width:425px;">Shanghai Haisheng Biotech Co., Ltd.</td>
			<td style="width:229px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:475px;">Wash Bottle, 500 ml</td>
			<td style="width:425px;">Sangon Biotech</td>
			<td style="width:229px;">F505001-0001</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sodium chloride</td>
			<td style="width:425px;">Vetec</td>
			<td style="width:229px;">V900058-500G</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Potassium Chloride</td>
			<td style="width:425px;">Sinopharm Chemical Reagent Co.,Ltd</td>
			<td style="width:229px;">10016318</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Calcium chloride</td>
			<td style="width:425px;">Sinopharm Chemical Reagent Co.,Ltd</td>
			<td style="width:229px;">20011160</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sodium bicarbonate&#160;</td>
			<td style="width:425px;">Vetec</td>
			<td style="width:229px;">v900182-500G</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Methylene Blue Hydrate</td>
			<td style="width:425px;">TCI</td>
			<td style="width:229px;">M0501</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Hydrochloric acid</td>
			<td style="width:425px;">Sinopharm Chemical Reagent Co.,Ltd</td>
			<td style="width:229px;">10011008</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:475px;">Sea Salts</td>
			<td>Instant Ocean</td>
			<td style="width:229px;">SS15-10</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Pipetter</td>
			<td style="width:425px;">Fisherbrand</td>
			<td style="width:229px;">13-675M</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:475px;">Controlled Drop Pasteur Pipet</td>
			<td style="width:425px;">Fisherbrand</td>
			<td style="width:229px;">13-678-30</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:475px;">Microscope</td>
			<td style="width:425px;">OLYMPUS</td>
			<td style="width:229px;">SZ61</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Biochemical incubator</td>
			<td>Shanghai Yiheng Scientific Instrument Co., Ltd.</td>
			<td>LRH-250</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">3D printer</td>
			<td>UnionTech</td>
			<td>Lite600</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Photosensitive resin</td>
			<td>UnionTech</td>
			<td>UTR9000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Vacuum pump</td>
			<td>Shanghai Yukang Scientific Instrument Co., Ltd.</td>
			<td>SHB-IIIA</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:475px;">Adhesive PCR Plate Seals</td>
			<td style="width:425px;">Solarbio</td>
			<td style="width:229px;">YA0245</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">96 well plate</td>
			<td style="width:425px;">Costar</td>
			<td style="width:229px;">3599</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:475px;">Multi 8-channel pipette 30 - 300 &#956;l</td>
			<td style="width:425px;">Eppendorf</td>
			<td style="width:229px;">3122000.051</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:475px;">Compressed Gas Duster</td>
			<td style="width:425px;">Shanghai Zhantu Chemical Co., Ltd.</td>
			<td style="width:229px;">ST1005</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:475px;">DI Water</td>
			<td style="width:425px;">Thermo</td>
			<td style="width:229px;">GenPure Pro UV/UF</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:475px;">Drying oven</td>
			<td style="width:425px;">Shanghai Yiheng Scientific Instrument Co., Ltd.</td>
			<td style="width:229px;">BPG-9106A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:475px;">System water</td>
			<td style="width:425px;"></td>
			<td style="width:229px;"></td>
			<td style="width:429px;">Water out of the facility&#8217;s water system</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:475px;">Egg water</td>
			<td style="width:425px;"></td>
			<td style="width:229px;"></td>
			<td style="width:429px;">Dilute 60mg &#8220;Instant Ocean&#8221; sea salts and 0.25 mg/L methylene blue in 1 L DI water</td>
		</tr>
		<tr height="116">
			<td height="116" style="height:116px;width:475px;">Holtfreter&#8217;s solution</td>
			<td style="width:425px;"></td>
			<td style="width:229px;"></td>
			<td style="width:429px;">Dissolve 7.0 g Sodium chloride (NaCl), 0.4 g Sodium bicarbonate (NaHCO3), 0.1 g Potassium Chloride (KCl), 0.235 g Calcium chloride (CaCl2.2H2O) in 1.9 L DI water. Adjust pH to 7 using HCl and adjust volume to 2 L using Di water</td>
		</tr>
	</tbody>
</table>

a 3-dimensional (3d)-printed template for high throughput zebrafish embryo arraying

The zebrafish is a globally recognized fresh water organism frequently used in developmental biology, environmental toxicology, and human disease related research fields. Thanks to its unique features, including large fecundity, embryo translucency, rapid and simultaneous development, etc., zebrafish embryos are often used for large scale toxicity assessment of chemicals and drug/compound screening. A typical screening procedure involves adult zebrafish spawning, embryos selection, and arraying the embryos into multi-well plates. From there, embryos are subjected to exposure and the toxicity of chemical, or the effectiveness of the drugs/compounds can be evaluated relatively quickly based on phenotypic observations. Among these processes, embryos arraying is one of the most time-consuming and labor-intensive steps that limits the throughput level. In this protocol, we present an innovative approach that makes use of a 3D-printed arraying template coupled with vacuum manipulation to speed up this laborious step. The protocol herein describes the overall design of the arraying template, a detailed experimental setup and step-by-step procedure, followed by representative results. When implemented, this approach should prove beneficial in a variety of research applications using zebrafish embryos as testing subjects.

Figure 3 shows a typical 3D-printed arraying template. This template uses photosensitive resin as raw material and was made by a 3D printer; a layer of black paint was applied to provide a better contrast to the color of embryos. The position of 96 wells (12 by 8) was designed to fit with a standard 96-well plate. Similarly, a 384 (24 by 16) well template could also be designed and fabricated using the same method. The upside chamber was slightly bigger than ...

Watch this Scientific Journal Video about A 3-dimensional 3D-printed Template for High Throughput Zebrafish Embryo Arraying at JoVE.com

A 3-dimensional 3D-printed Template for High Throughput Zebrafish Embryo Arraying

Here, we present a protocol to design and fabricate a zebrafish embryo arraying template, followed by a detailed procedure on the use of such template for high throughput zebrafish embryo arraying into a 96-well plate.

A 3-dimensional (3D)-printed Template for High Throughput Zebrafish Embryo Arraying

The zebrafish is a globally recognized fresh water organism frequently used in developmental biology, environmental toxicology, and human disease related ...

This method can significantly speed up the Zebrafish embryo arraying procedure and make Zebrafish truly amenable for high throughput screening. The main advantage of this technique is the use of a 3D printed template to pre-array Zebrafish embryos into a 96 or 384 well matrix, which facilitates a highly efficient plate preparation process. We first had the idea for the method while performing the screening of nanoparticles by manually picking and selecting individual embryos into each well of a modular plate and wanted to increase efficiency.In addition to Tianyu, fellow graduate student Yue Jiang will be demonstrating the procedure. Begin this procedure with design of the arraying template with a twelve by eight 96 well layout that fits a standard 96 well plate. As detailed in the text protocol.Use a 3D printer with a 0.1 millimeter precision to print the template. Some key components of the template are the entrapment chamber, the entrapment well, the vacuum chamber, and the air-in outlet. To perform the Zebrafish embryo spawning, first separate males and females by a clear plastic divider.Then, place two pairs of male and female fish per mating box one day prior to spawning. On the day of spawning, take off the dividers in the morning to mix male and female fish. Remove the male and female fish and collect Zebrafish embryos using a fine mesh strainer.Wash the embryos with 250 milliliters of egg water. Transfer the collected embryos to Petri dishes with Holtfreter's Solution. Remove the dead and unfertilized embryos using a stereo microscope.Place the embryos in a 28.5 degrees Celsius incubator. At four hours post-fertilization, observe the embryos and remove any dead and unhealthy embryos. The embryos are now ready for the next step.Wash the template two to three times with 500 milliliters of deionized water before putting it into the drying oven for five minutes. Then, tape the bottom chamber with a piece sealing film. Connect a vacuum pump through the air outlet at the bottom of the template to generate negative pressure in the chamber sealed by the sealing film.Using a plastic transfer pipette, place approximately 150 embryos into the template. Shake the entire template horizontally until each well has one embryo entrapped. With this step, it is critical to check and make sure on every available Zebrafish embryo.If the Holtfreter buffer was very low, one could add additional buffer by shaking the template. Discard extra Holtfreter's Solution and embryos that are not entrapped in the wells. Turn off and disconnect the vacuum pump.Place a standard 96 well plate upside down against the template and rotate both at the same time. Tap the bottom of the template or connect the air outlet to a compressed gas dusting can to transfer all trapped embryos from the template to the 96 well plate. Finally, remove the sealing film and wash the template three times from top to bottom with 500 milliliters of deionized water for future use.Shown here is the partial image of a 96 well plate arrayed by the template. Conversely, this image shows the partial image of a 96 well plate arrayed manually. The overall health status of the embryos after being plated by manual and arraying template methods is displayed here.Based on the hatching, survival, and malformation rates of the embryos, no significant effects on the overall health of the embryos were observed in either case. Once mastered, this technique will prepare one 96 or 384 well plate just in two to three minutes if performed properly. After its development, this technique paved the way for researchers to take full advantage of the new features of this model organism and truly achieve in vitro high throughput screening.

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Research

JoVE Journal

Environment

Determination of Microbial Extracellular Enzyme Activity in Waters, Soils, and Sediments using High Throughput Microplate Assays

Much of the nutrient cycling and carbon processing in natural environments occurs through the activity of extracellular enzymes released by microorganisms. Thus, measurement of the activity of these extracellular enzymes can give insights into the rates of ecosystem level processes, such as organic matter decomposition or nitrogen and phosphorus mineralization. Assays of extracellular enzyme activity in environmental samples typically involve exposing the samples to artificial colorimetric or fluorometric substrates and tracking the rate of substrate hydrolysis. Here we describe microplate based methods for these procedures that allow the analysis of large numbers of samples within a short time frame. Samples are allowed to react with artificial substrates within 96-well microplates or deep well microplate blocks, and enzyme activity is subsequently determined by absorption or fluorescence of the resulting end product using a typical microplate reader or fluorometer. Such high throughput procedures not only facilitate comparisons between spatially separate sites or ecosystems, but also substantially reduce the cost of such assays by reducing overall reagent volumes needed per sample.

Microplate based procedures are described for the colorimetric or fluorometric analysis of extracellular enzyme activity. These procedures allow for the rapid assay of such activity in large numbers of environmental samples within a manageable time frame.

Much of the nutrient cycling and carbon  processing in natural environments occurs through the activity of extracellular  enzymes released by ...

High-throughput Fluorometric Measurement of Potential Soil Extracellular Enzyme Activities

Microbes in soils and other environments produce extracellular enzymes to depolymerize and hydrolyze organic macromolecules so that they can be assimilated for energy and nutrients. Measuring soil microbial enzyme activity is crucial in understanding soil ecosystem functional dynamics. The general concept of the fluorescence enzyme assay is that synthetic C-, N-, or P-rich substrates bound with a fluorescent dye are added to soil samples. When intact, the labeled substrates do not fluoresce. Enzyme activity is measured as the increase in fluorescence as the fluorescent dyes are cleaved from their substrates, which allows them to fluoresce. Enzyme measurements can be expressed in units of molarity or activity. To perform this assay, soil slurries are prepared by combining soil with a pH buffer. The pH buffer (typically a 50 mM sodium acetate or 50 mM Tris buffer), is chosen for the buffer&#39;s particular acid dissociation constant (pKa) to best match the soil sample pH. The soil slurries are inoculated with a nonlimiting amount of fluorescently labeled (i.e. C-, N-, or P-rich) substrate. Using soil slurries in the assay serves to minimize limitations on enzyme and substrate diffusion. Therefore, this assay controls for differences in substrate limitation, diffusion rates, and soil pH conditions; thus detecting potential enzyme activity rates as a function of the difference in enzyme concentrations (per sample).
Fluorescence enzyme assays are typically more sensitive than spectrophotometric (i.e. colorimetric) assays,&#160;but can suffer from interference caused by impurities and the instability of many fluorescent compounds when exposed to light; so caution is required when handling fluorescent substrates. Likewise, this method only assesses potential enzyme activities under laboratory conditions when substrates are not limiting. Caution should be used when interpreting the data representing cross-site comparisons with differing temperatures or soil types, as in situ soil type and temperature can influence enzyme kinetics.

To measure potential rates of soil extracellular enzyme activities, synthetic substrates that are bound to a fluorescent dye are added to soil samples. Enzyme activity is measured as the fluorescent dye is released from the substrate by an enzyme-catalyzed reaction, where higher fluorescence indicates more substrate degradation.

Microbes in soils and other environments produce extracellular enzymes to depolymerize and hydrolyze organic macromolecules so that they can be ...

Optimized Negative Staining: a High-throughput Protocol for Examining Small and Asymmetric Protein Structure by Electron Microscopy

Structural determination of proteins is rather challenging for proteins with molecular masses between 40 - 200 kDa. Considering that more than half of natural proteins have a molecular mass between 40 - 200 kDa1,2, a robust and high-throughput method with a nanometer resolution capability is needed. Negative staining (NS) electron microscopy (EM) is an easy, rapid, and qualitative approach which has frequently been used in research laboratories to examine protein structure and protein-protein interactions. Unfortunately, conventional NS protocols often generate structural artifacts on proteins, especially with lipoproteins that usually form presenting rouleaux artifacts. By using images of lipoproteins from cryo-electron microscopy (cryo-EM) as a standard, the key parameters in NS specimen preparation conditions were recently screened and reported as the optimized NS protocol (OpNS), a modified conventional NS protocol 3 . Artifacts like rouleaux can be greatly limited by OpNS, additionally providing high contrast along with reasonably high&#8208;resolution (near 1 nm) images of small and asymmetric proteins. These high-resolution and high contrast images are even favorable for an individual protein (a single object, no average) 3D reconstruction, such as a 160 kDa antibody, through the method of electron tomography4,5. Moreover, OpNS can be a high&#8208;throughput tool to examine hundreds of samples of small proteins. For example, the previously published mechanism of 53 kDa cholesteryl ester transfer protein (CETP) involved the screening and imaging of hundreds of samples 6. Considering cryo-EM rarely successfully images proteins less than 200 kDa has yet to publish any study involving screening over one hundred sample conditions, it is fair to call OpNS a high-throughput method for studying small proteins. Hopefully the OpNS protocol presented here can be a useful tool to push the boundaries of EM and accelerate EM studies into small protein structure, dynamics and mechanisms.

More than half of proteins are small proteins (molecular mass &#60;200 kDa) that are challenging for both electron microscope imaging and three-dimensional reconstructions. Optimized negative staining is a robust and high-throughput protocol to obtain high contrast and relatively high resolution (~1 nm) images of small asymmetric proteins or complexes under different physiological conditions.

Structural determination of proteins is rather challenging for proteins with molecular masses between 40 - 200 kDa. Considering that more than half of ...

Semi-High Throughput Screening for Potential Drought-tolerance in Lettuce (Lactuca sativa) Germplasm Collections

This protocol describes a method by which a large collection of the leafy green vegetable lettuce (Lactuca sativa L.) germplasm was screened for likely drought-tolerance traits. Fresh water availability for agricultural use is a growing concern across the United States as well as many regions of the world. Short-term drought events along with regulatory intervention in the regulation of water availability coupled with the looming threat of long-term climate shifts that may lead to reduced precipitation in many important agricultural regions has increased the need to hasten the development of crops adapted for improved water use efficiency in order to maintain or expand production in the coming years. This protocol is not meant as a step-by-step guide to identifying at either the physiological or molecular level drought-tolerance traits in lettuce, but rather is a method developed and refined through the screening of thousands of different lettuce varieties. The nature of this screen is based in part on the streamlined measurements focusing on only three water-stress indicators: leaf relative water content, wilt, and differential plant growth following drought-stress. The purpose of rapidly screening a large germplasm collection is to narrow the candidate pool to a point in which more intensive physiological, molecular, and genetic methods can be applied to identify specific drought-tolerant traits in either the lab or field. Candidates can also be directly incorporated into breeding programs as a source of drought-tolerance traits.

Semi-High Throughput Screening for Potential Drought-tolerance in Lettuce Lactuca sativa Germplasm Collections

This protocol was developed to screen a large germplasm collection of the leafy vegetable lettuce (Lactuca sativa L.) for drought-tolerance, in order to identify a small candidate pool of lettuce for use in physiological, molecular, and genetic studies to identify underlying drought-tolerance traits along with breeding programs.

This protocol describes a method by which a large collection of the leafy green vegetable lettuce (Lactuca sativa L.) germplasm was screened for likely ...

High-throughput Screening of Recalcitrance Variations in Lignocellulosic Biomass: Total Lignin, Lignin Monomers, and Enzymatic Sugar Release

The conversion of lignocellulosic biomass to fuels, chemicals, and other commodities has been explored as one possible pathway toward reductions in the use of non-renewable energy sources. In order to identify which plants, out of a diverse pool, have the desired chemical traits for downstream applications, attributes, such as cellulose and lignin content, or monomeric sugar release following an enzymatic saccharification, must be compared. The experimental and data analysis protocols of the standard methods of analysis can be time-consuming, thereby limiting the number of samples that can be measured. High-throughput (HTP) methods alleviate the shortcomings of the standard methods, and permit the rapid screening of available samples to isolate those possessing the desired traits. This study illustrates the HTP sugar release and pyrolysis-molecular beam mass spectrometry pipelines employed at the National Renewable Energy Lab. These pipelines have enabled the efficient assessment of thousands of plants while decreasing experimental time and costs through reductions in labor and consumables.

Plant cell wall structure and chemistry traits are evaluated to identify ideal feedstocks for biofuels and bio-materials. Standard methods have limitations when applied to large data sets. These high-throughput pretreatment, enzyme saccharification, and pyrolysis-molecular beam mass spectrometry methods compare large numbers of biomass samples with decreased experimental time and cost.

The conversion of lignocellulosic biomass to fuels, chemicals, and other commodities has been explored as one possible pathway toward reductions in the ...

RGB and Spectral Root Imaging for Plant Phenotyping and Physiological Research: Experimental Setup and Imaging Protocols

Better understanding of plant root dynamics is essential to improve resource use efficiency of agricultural systems and increase the resistance of crop cultivars against environmental stresses. An experimental protocol is presented for RGB and hyperspectral imaging of root systems. The approach uses rhizoboxes where plants grow in natural soil over a longer time to observe fully developed root systems. Experimental settings are exemplified for assessing rhizobox plants under water stress and studying the role of roots. An RGB imaging setup is described for cheap and quick quantification of root development over time. Hyperspectral imaging improves root segmentation from the soil background compared to RGB color based thresholding. The particular strength of hyperspectral imaging is the acquisition of chemometric information on the root-soil system for functional understanding. This is demonstrated with high resolution water content mapping. Spectral imaging however is more complex in image acquisition, processing and analysis compared to the RGB approach. A combination of both methods can optimize a comprehensive assessment of the root system. Application examples integrating root and aboveground traits are given for the context of plant phenotyping and plant physiological research. Further improvement of root imaging can be obtained by optimizing RGB image quality with better illumination using different light sources and by extension of image analysis methods to infer on root zone properties from spectral data.

An experimental protocol is presented for assessment of soil grown plant root systems with RGB and hyperspectral imaging. Combination of RGB image time series with chemometric information from hyperspectral scans optimizes insights into plant root dynamics.

Better understanding of plant root dynamics is essential to improve resource use efficiency of agricultural systems and increase the resistance of crop ...

Basic Research in Plasma Medicine - A Throughput Approach from Liquids to Cells

In plasma medicine, ionized gases with temperatures close to that of vertebrate systems are applied to cells and tissues. Cold plasmas generate reactive species known to redox regulate biological processes in health and disease. Pre-clinical and clinical evidence points to beneficial effects of plasma treatment in the healing of chronic ulcer of the skin. Other emerging topics, such as plasma cancer treatment, are receiving increasing attention. Plasma medical research requires interdisciplinary expertise in physics, chemistry, and biomedicine. One goal of plasma research is to characterize plasma-treated cells in a variety of specific applications. This includes, for example, cell count and viability, cellular oxidation, mitochondrial activity, cytotoxicity and mode of cell death, cell cycle analysis, cell surface marker expression, and cytokine release. This study describes the essential equipment and workflows required for such research in plasma biomedicine. It describes the proper operation of an atmospheric pressure argon plasma jet, specifically monitoring its basic emission spectra and feed gas settings to modulate reactive species output. Using a high-precision xyz-table and computer software, the jet is hovered in millisecond-precision over the cavities of 96-well plates in micrometer-precision for maximal reproducibility. Downstream assays for liquid analysis of redox-active molecules are shown, and target cells are plasma-treated. Specifically, melanoma cells are analyzed in an efficient sequence of different consecutive assays but using the same cells: measurement of metabolic activity, total cell area, and surface marker expression of calreticulin, a molecule important for the immunogenic cell death of cancer cells. These assays retrieve content-rich biological information about plasma effects from a single plate. Altogether, this study describes the essential steps and protocols for plasma medical research.

A high-throughput cold physical plasma treatment protocol of liquids and cells is shown. It involves setting up different feed gas compositions for plasma ignition, measuring the plasma&#39;s emission spectra, and the subsequent analysis of liquids and cellular activity after plasma treatment.

In plasma medicine, ionized gases with temperatures close to that of vertebrate systems are applied to cells and tissues. Cold plasmas generate reactive ...

High-throughput, Microscale Protocol for the Analysis of Processing Parameters and Nutritional Qualities in Maize (Zea mays L.)

Maize is an important grain crop in the United States and worldwide. However, maize grain must be processed prior to human consumption. Furthermore, whole grain composition and processing characteristics vary among maize hybrids and can impact the quality of the final processed product. Therefore, in order to produce healthier processed food products from maize, it is necessary to know how to optimize processing parameters for particular sets of germplasm to account for these differences in grain composition and processing characteristics. This includes a better understanding of how current processing techniques impact the nutritional quality of the final processed food product. Here, we describe a microscale protocol that both simulates the processing pipeline to produce cornflakes from large flaking grits and allows for the processing of multiple grain samples simultaneously. The flaking grits, the intermediate processed products, or final processed product, as well as the corn grain itself, can be analyzed for nutritional content as part of a high-throughput analytical pipeline. This procedure was developed specifically for incorporation into a maize breeding research program, and it can be modified for other grain crops. We provide an example of the analysis of insoluble-bound ferulic acid and p-coumaric acid content in maize. Samples were taken at five different processing stages. We demonstrate that sampling can take place at multiple stages during microscale processing, that the processing technique can be utilized in the context of a specialized maize breeding program, and that, in our example, most of the nutritional content was lost during food product processing.

High-throughput, Microscale Protocol for the Analysis of Processing Parameters and Nutritional Qualities in Maize Zea mays L.

Here, we present a microscale protocol for processing grain samples and for incorporating this microscale approach into a high-throughput analytical pipeline. This is a higher throughput adaptation of currently available protocols.

Maize is an important grain crop in the United States and worldwide. However, maize grain must be processed prior to human consumption. Furthermore, whole ...

Single-throughput Complementary High-resolution Analytical Techniques for Characterizing Complex Natural Organic Matter Mixtures

Natural organic matter (NOM) is composed of a highly complex mixture of thousands of organic compounds which, historically, proved difficult to characterize. However, to understand the thermodynamic and kinetic controls on greenhouse gas (carbon dioxide [CO2] and methane [CH4]) production resulting from the decomposition of NOM, a molecular-level characterization coupled with microbial proteome analyses is necessary. Further, climate and environmental changes are expected to perturb natural ecosystems, potentially upsetting complex interactions that influence both the supply of organic matter substrates and the microorganisms performing the transformations. A detailed molecular characterization of the organic matter, microbial proteomics, and the pathways and transformations by which organic matter is decomposed will be necessary to predict the direction and magnitude of the effects of environmental changes. This article describes a methodological throughput for comprehensive metabolite characterization in a single sample by direct injection Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS), gas chromatography mass spectrometry (GC-MS), nuclear magnetic resonance (NMR) spectroscopy, liquid chromatography mass spectrometry (LC-MS), and proteomics analysis. This approach results in a fully-paired dataset which improves statistical confidence for inferring pathways of organic matter decomposition, the resulting CO2 and CH4 production rates, and their responses to environmental perturbation. Herein we present results of applying this method to NOM samples collected from peatlands; however, the protocol is applicable to any NOM sample (e.g., peat, forested soils, marine sediments, etc.).

This protocol describes a single throughput for complementary analytical and omics techniques culminating in a fully-paired characterization of natural organic matter and microbial proteomics in different ecosystems. This approach permits robust comparisons for identifying metabolic pathways and transformations important for describing greenhouse gas production and predicting responses to environmental change.

Natural organic matter (NOM) is composed of a highly complex mixture of thousands of organic compounds which, historically, proved difficult to ...

Evaluation of the Productivity of Social Wasp Colonies (Vespinae) and an Introduction to the Traditional Japanese Vespula Wasp Hunting Technique

For vespine wasps, colony productivity is typically estimated by counting the number of larval cells. This paper presents an improved method that enables researchers to estimate more accurately the number of adults produced, counting the number of meconia (the stools left in the cells by wasp larvae when pupating into adults, per 100 cells) in each comb. This method can be applied before or after colony collapse (i.e., in active or inactive nests). The paper also describes how to locate wild Vespula wasp colonies by &#34;flagging&#34; wasp baits and chasing the wasp collecting them, using a method traditionally performed by local people in central Japan (as illustrated in the associated video). The Vespula chasing method described has several advantages: it is easy to reinitiate the chase from a point where the forager flying back to the nest was lost, and it is easy to pinpoint the nest location as marked wasps often lose their flag at the nest entrance. These methods for estimating colony productivity and collecting nests can be valuable for researchers studying social wasps.

Evaluation of the Productivity of Social Wasp Colonies Vespinae and an Introduction to the Traditional Japanese Vespula Wasp Hunting Technique

This methodological paper evaluates the productivity of a social wasp colony by examining the number of meconia per 100 cells of comb, to estimate the total number of adults the wasps produced. The associated video describes how to search for Vespula wasp nests, a method developed by amateur wasp chasers.

For vespine wasps, colony productivity is typically estimated by counting the number of larval cells. This paper presents an improved method that enables ...