Name: studying neurobehavioral effects of environmental pollutants on zebrafish larvae
Uploaded: 2020-02-05T15:00:00
Description: Watch this Scientific Journal Video about Studying Neurobehavioral Effects of Environmental Pollutants on Zebrafish Larvae at JoVE.com

The authors are grateful for the financial support by the National Natural Science Foundation of China (21876135 and 21876136), the National Major Science and Technology Project of China (2017ZX07502003-03, 2018ZX07701001-22), the Foundation of MOE-Shanghai Key Laboratory of Children&#39;s Environmental Health (CEH201807-5), and Swedish Research Council (No. 639-2013-6913).

The protocol is in accordance with guidelines approved by the Animal Ethics Committee of Tongji University.
1. Zebrafish embryo collection
<ol>
	<li>Put two pairs of healthy adult Tubingen zebrafish into the spawning box on the night before exposure, keeping the sex ratio at 1:1.</li>
	<li>Remove the adult fish back to the system 30-60 min after daylight the next morning.</li>
	<li>Remove the embryos out of the spawning box.</li>
	<li>Rinse the embryos with system water.</li>
	<li>Transfer t...

<ol>
	<li>Sun, L., 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=Developmental+neurotoxicity+of+organophosphate+flame+retardants+in+early+life+stages+of+Japanese+medaka+(Oryzias+latipes).">Developmental neurotoxicity of organophosphate flame retardants in early life stages of Japanese medaka (Oryzias latipes).</a> Environmental Toxicology and Chemistry. 35 (12), 2931-2940 (2016).</li><li>Tian, L., 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=Neurotoxicity+induced+by+zinc+oxide+nanoparticles:+age-related+differences+and+interaction.">Neurotoxicity induced by zinc oxide nanoparticles: age-related differences and interaction.</a> Scientific Reports. 5, 16117 (2015).</li><li>Rauh, V. A., Margolis, A. 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M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Environmental Organic Chemistry. , (2016).</li><li>Akortia, E., 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=A+review+of+sources,+levels,+and+toxicity+of+polybrominated+diphenyl+ethers+(PBDEs)+and+their+transformation+and+transport+in+various+environmental+compartments.">A review of sources, levels, and toxicity of polybrominated diphenyl ethers (PBDEs) and their transformation and transport in various environmental compartments.</a> Environmental Reviews. 24 (3), 253-273 (2016).</li><li>Shaw, B. J., Liddle, C. C., Windeatt, K. M., Handy, R. 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Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Locomotor+activity+changes+on+zebrafish+larvae+with+different+2,+2?,+4,+4?-tetrabromodiphenyl+ether+(PBDE-47)+embryonic+exposure+modes.">Locomotor activity changes on zebrafish larvae with different 2, 2?, 4, 4?-tetrabromodiphenyl ether (PBDE-47) embryonic exposure modes.</a> Chemosphere. 94, 53-61 (2014).</li><li>Zhang, B., 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=Neurobehavioral+effects+of+two+metabolites+of+BDE-47+(6-OH-BDE-47+and+6-MeO-BDE-47)+on+zebrafish+larvae.">Neurobehavioral effects of two metabolites of BDE-47 (6-OH-BDE-47 and 6-MeO-BDE-47) on zebrafish larvae.</a> Chemosphere. 200, 30-35 (2018).</li><li>Yang, 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=The+chlorine+contents+and+chain+lengths+influence+the+neurobehavioral+effects+of+commercial+chlorinated+paraffins+on+zebrafish+larvae.">The chlorine contents and chain lengths influence the neurobehavioral effects of commercial chlorinated paraffins on zebrafish larvae.</a> Journal of Hazardous Materials. 377, 172-178 (2019).</li><li>Schmitt, C., McManus, M., Kumar, N., Awoyemi, O., Crago, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparative+analyses+of+the+neurobehavioral,+molecular,+and+enzymatic+effects+of+organophosphates+on+embryo-larval+zebrafish+(Danio+rerio).">Comparative analyses of the neurobehavioral, molecular, and enzymatic effects of organophosphates on embryo-larval zebrafish (Danio rerio).</a> Neurotoxicology and Teratology. 73, 67-75 (2019).</li><li>Li, X., Kong, H., Ji, X., Gao, Y., Jin, 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+behavioral+phenomics+applied+for+phenotyping+aquatic+neurotoxicity+induced+by+lead+contaminants+of+environmentally+relevant+level.">Zebrafish behavioral phenomics applied for phenotyping aquatic neurotoxicity induced by lead contaminants of environmentally relevant level.</a> Chemosphere. 224, 445-454 (2019).</li><li>Leuthold, D., Klu&#776;ver, N., Altenburger, R., Busch, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Can+environmentally+relevant+neuroactive+chemicals+specifically+be+detected+with+the+locomotor+response+test+in+zebrafish+embryos?.">Can environmentally relevant neuroactive chemicals specifically be detected with the locomotor response test in zebrafish embryos?.</a> Environmental Science &amp; Technology. 53 (1), 482-493 (2018).</li><li>Kinch, C. D., Ibhazehiebo, K., Jeong, J. H., Habibi, H. R., Kurrasch, D. 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Effect of swimming speed.</a> Journal of Experimental Biology. 207 (19), 3265-3279 (2004).</li><li>Westerfield, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+guide+for+the+laboratory+use+of+zebrafish+(Danio+rerio).">A guide for the laboratory use of zebrafish (Danio rerio).</a> The Zebrafish Book. 4, (2000).</li><li>Ying, L., Jiang, L., Bo, P., Yong, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Teratogenic+effects+of+embryonic+exposure+to+pretilachlor+on+the+larvae+of+zebrafish.">Teratogenic effects of embryonic exposure to pretilachlor on the larvae of zebrafish.</a> Journal of Agro-Environment Science. 36 (3), 481-486 (2017).</li><li>Macphail, R. C., 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=Locomotion+in+larval+zebrafish:+Influence+of+time+of+day,+lighting+and+ethanol.">Locomotion in larval zebrafish: Influence of time of day, lighting and ethanol.</a> Neurotoxicology. 30 (1), 52-58 (2009).</li><li>Kais, B., 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=DMSO+modifies+the+permeability+of+the+zebrafish+(Danio+rerio)+chorion-implications+for+the+fish+embryo+test+(FET).">DMSO modifies the permeability of the zebrafish (Danio rerio) chorion-implications for the fish embryo test (FET).</a> Aquatic Toxicology. 140, 229-238 (2013).</li><li>Truong, L., Harper, S. L., Tanguay, R. 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This work provides a detailed experimental protocol to evaluate the neurotoxicity of environmental pollutants using zebrafish larvae. Zebrafish go through the process from embryos to larvae during the exposure period, which means that good care of the embryos and larvae is essential. Anything that affects the development of the embryos and larvae can influence the final result. Here the culture environment, exposure process, and experimental conditions are discussed to ensure the success of the whole assay.
<p class=...

In recent years more and more environmental pollutants have been proved neurotoxic1,2,3,4. However, the assessment of neurotoxicity in vivo after exposure to environmental pollutants is not as easy as that of endocrine disruption or developmental toxicity. In addition, early exposure to pollutants, especially at environmentally relevant doses, has attracted increasing attention in toxicity studies5,6,7,8.
Zebrafish is being established as an animal model fit for neurotoxicity studies during early development after exposure to environmental pollutants. Zebrafish are vertebrates that develop faster than other species after fertilization. The larvae do not need to be fed because the nutrients in the chorion are enough for sustain them for 7 days postfertilization (dpf)9. Larvae come out from the chorion at ~2 dpf and develop behaviors such as swimming and turning that can be observed, tracked, quantified, and analyzed automatically using behavior instruments10,11,12,13 starting at 3-4 dpf14,15,16,17,18. In addition, high-throughput tests can also be realized by behavior instruments. Thus, zebrafish larvae are an outstanding model for the neurobehavioral study of environmental pollutants19. Here, a protocol is offered using high-throughput monitoring to study the neurobehavioral toxicity of environmental pollutants on zebrafish larvae under light stimuli.
Our lab has studied the neurobehavioral toxicity of 2,2&#39;,4,4&#39;-tetrabromodiphenyl ether (BDE-47)20,21, 6&#39;-Hydroxy/Methoxy-2,2&#39;,4,4&#39;-tetrabromodiphenyl ether (6-OH/MeO-BDE-47)22, deca-brominated diphenyl ether (BDE-209), lead, and commercial chlorinated paraffins23 using the presented protocol. Many labs also use the protocol to study the neurobehavioral effects of other pollutants on larvae or adult fish24,25,26,27. This neurobehavioral protocol was used to help provide mechanistic support showing that low-dose exposure to bisphenol A and replacement bisphenol S induced premature hypothalamic neurogenesis in embryonic zebrafish27. In addition, some researchers optimized the protocol to perform corresponding studies. A recent study eliminated the toxicity of amyloid beta (A&#946;) in an easy, high-throughput zebrafish model using casein-coated gold nanoparticles (&#946;Cas AuNPs). It showed that &#946;Cas AuNPs in systemic circulation translocated across the blood-brain barrier of zebrafish larvae and sequestered intracerebral A&#946;42, eliciting toxicity in a nonspecific, chaperone-like manner, which was supported by behavioral pathology28.
Locomotion, path angle, and social activity are three neurobehavioral indicators used to study the neurotoxicity effects of zebrafish larvae after exposure to pollutants in the presented protocol. Locomotion is measured by the swimming distance of larvae and can be damaged after exposure to pollutants. Path angle and social activity are more closely related with the function of the brain and the central nervous system29. The path angle refers to the angle of the path of animal motion relative to the swimming direction30. Eight angle classes from ~-180&#176;-~+180&#176; are set in the system. To simplify the comparison, six classes in the final outcome are defined as routine turns (-10&#176; ~0&#176;, 0&#176; ~+10&#176;), average turns (-10&#176; ~-90&#176;, +10&#176; ~+90&#176;), and responsive turns (-180&#176; ~-90&#176;, +90&#176; ~+180&#176;) according to our previous studies21,22. Two-fish social activity is fundamental of group shoaling behavior; here a distance of &#60; 0.5 cm between two larvae valid is defined as social contact.
The protocol presented here demonstrates a clear process for studying neurobehavioral effects on zebrafish larvae and provides a way to reveal the neurotoxicity effects of various substances or pollutants. The protocol will benefit researchers interested in studying the neurotoxicity of environmental pollutants.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>48-well-microplate</td>
			<td>Corning</td>
			<td>3548</td>
			<td>Embyros housing</td>
		</tr>
		<tr>
			<td>6-well-microplate</td>
			<td>Corning</td>
			<td>3471</td>
			<td>Embyros housing</td>
		</tr>
		<tr>
			<td>BDE-47</td>
			<td>AccuStandard</td>
			<td>5436-43-1</td>
			<td>Pollutant</td>
		</tr>
		<tr>
			<td>DMSO</td>
			<td>Sigma</td>
			<td>67-68-5</td>
			<td>Cosolvent</td>
		</tr>
		<tr>
			<td>Microscope</td>
			<td>Olympus</td>
			<td>SZX 16</td>
			<td>Observation instrument</td>
		</tr>
		<tr>
			<td>Pipette</td>
			<td>Eppendorf</td>
			<td>3120000267</td>
			<td>Transfer solution</td>
		</tr>
		<tr>
			<td>Zebrabox</td>
			<td>Viewpoint</td>
			<td>ZebraBox</td>
			<td>Behavior instrument</td>
		</tr>
		<tr>
			<td>Zebrafish</td>
			<td>Shanghai FishBio Co., Ltd.</td>
			<td>Tubingen</td>
			<td>Zebrafish supplier</td>
		</tr>
		<tr>
			<td>ZebraLab</td>
			<td>Viewpoint</td>
			<td>ZebraLab</td>
			<td>Behavior software</td>
		</tr>
	</tbody>
</table>

studying neurobehavioral effects of environmental pollutants on zebrafish larvae

Recent years more and more environmental pollutants have been proved neurotoxic, especially at the early development stages of organisms. Zebrafish larvae are a preeminent model for the neurobehavioral study of environmental pollutants. Here, a detailed experimental protocol is provided for the evaluation of the neurotoxicity of environmental pollutants using zebrafish larvae, including the collection of the embryos, the exposure process, neurobehavioral indicators, the test process, and data analysis. Also, the culture environment, exposure process, and experimental conditions are discussed to ensure the success of the assay. The protocol has been used in the development of psychopathic drugs, research on environmental neurotoxic pollutants, and can be optimized to make corresponding studies or be helpful for mechanistic studies. The protocol demonstrates a clear operation process for studying neurobehavioral effects on zebrafish larvae and can reveal the effects of various neurotoxic substances or pollutants.

Here, we describe a protocol for studying the neurobehavioral effects of environmental pollutants using zebrafish larvae under light stimuli. The locomotion, path angle, and social activity tests are defined in the introduction. The setup of the microplates in the locomotion and path angle tests and the images of the software are shown below. In addition, our own research results are presented as examples. Two studies present the locomotion and path angle effects after exposure to BDE-47 ...

Watch this Scientific Journal Video about Studying Neurobehavioral Effects of Environmental Pollutants on Zebrafish Larvae at JoVE.com

Studying Neurobehavioral Effects of Environmental Pollutants on Zebrafish Larvae

A detailed experimental protocol is presented in this paper for the evaluation of neurobehavioral toxicity of environmental pollutants using a zebrafish larvae model, including the exposure process and tests for neurobehavioral indicators.

Recent years more and more environmental pollutants have been proved neurotoxic, especially at the early development stages of organisms. Zebrafish larvae ...

Our protocol provides a clear process for studying the neurobehavioral effects of the substances and the pollutants of interest on zebrafish larvae and for revealing the potential neurotoxicity of these agents. The technique can be performed using high throughput testing of neurobehaviors in the zebrafish model. This method can be applied to evaluate allele-neurobehavioral effects of pollutants to demonstrate potential neurotoxicity on us humans, as zebrafish genome has a high homology with humans, so it can provide indications for chemical management and the public health problems caused by pollutants.As zebrafish has the advantage of high throughput screening, this method provides insight into both development of psychotropic drugs and environmental toxicology research. Don't be intimidated about studying the first experiment. If you follow the protocol, you will have a successful outcome.At least two hours before performing an experiment, set the room temperature to 28 degrees Celsius and add 800 microliters of exposure solution to each well of a 48-well microplate. Then, use a one-milliliter pipette with a modified tip to transfer one larva in 200 microliters of exposure solution to each well of the microplate in preparation for a locomotion and path angle experiment. To prepare a six-well microplate for social behavior experiments, add four milliliters of exposure solution to each well of the six well microplate and transfer two larvae in 200 microliters of exposure solution to each well.Before beginning the test, open the high throughput monitoring software program and select the tracking rotations path angles module. Transfer the 48-well microplate to the recording platform and pull down the cover. Click File and Generate Protocol to begin generating a new protocol and enter 48 into the Location count position.Click Parameters, Protocol Parameters, and Time, set the Experiment duration to one hour and 10 minutes, and the Integration period to 60 seconds. Using the elliptical shape tool, draw a circle around the top left well. Select the circle and click Copy, Top Right Mark, Paste, and Select.Use the mouse to drag the copied circle to the top right well and click Copy, Top Right Mark, Paste, and Select again. Then, drag the copied circle to the bottom right well and click Build and Clear Marks. The system will automatically draw a circle over every other well of the plate.Next, click Draw Scale and draw a calibration line on the screen. Enter the length of the line, set the unit, and click Apply to Group. Set the animal color to black and set the detection threshold to 16 to 18 to allow detection of the animals, set the inactive to small speed to 0.5 centimeters per second and the small to large speed to 2.5 centimeters per second.Set the path angle classes from minus 180 to plus 180 as indicated. To set the light conditions, click Parameters, Light Driving, Uses one of the 3 triggering methods below, and Enhanced stimuli to set the light conditions. Click Edge and set a dark period of 10 minutes, followed by three cycles of alternating 10-minute light and dark periods.Then, save the protocol. When all of the parameters have been set, turn down the lighting in the test room, and allow the larvae to acclimate in the system for 10 minutes. At the end of the acclimation period, click Experiment and Execute, and create the folder in which the experimental files are to be saved.Then, enter the result name and click Background and Start. At the end of the experiment, click Experiment and Stop. Then return the 48-well microplate back to the light incubator for subsequent experiments.Because every group can include 16 animals, the system can be used to perform high throughput tests of the locomotion and path angle under different treatment conditions in a single 48-well microplate. The social activity of the larvae can be tested using six-well plates. In this representative experiment, the highest concentration group of BDE-47 demonstrated a pronounced hypoactivity during the dark period, while no changes due to BDE-47 exposure were observed during the light periods.Further, the high concentration group of 6-hydroxy-BDE-47 performed fewer routine and average turns at five days post-fertilization. However, more responsive turns were induced in the 6-methoxy-BDE47 exposure groups. The social activity of the zebrafish was stimulated by chlorinated paraffin-70 and the short-chain chlorinated paraffin-52b, while the long-chain chlorinated paraffin-52a shortened the duration for contact of the larvae.It's important to make sure that the transferred larvae for the test should have a normal swimming ability and no malformations. Other variables, such as color preference, light-dark preference, all darkness, tail movements of zebrafish, can be included to answer additional questions about neurobehavioral toxicity of environmental pollutants. The BDE-47 exposure solutions are neurotoxic and have endocrine disruption potential, so be sure to avoid direct contact with skin.

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Research

JoVE Journal

Environment

Exploring the Effects of Atmospheric Forcings on Evaporation: Experimental Integration of the Atmospheric Boundary Layer and Shallow Subsurface

Evaporation is directly influenced by the interactions between the atmosphere, land surface and soil subsurface. This work aims to experimentally study evaporation under various surface boundary conditions to improve our current understanding and characterization of this multiphase phenomenon as well as to validate numerical heat and mass transfer theories that couple Navier-Stokes flow in the atmosphere and Darcian flow in the porous media. Experimental data were collected using a unique soil tank apparatus interfaced with a small climate controlled wind tunnel. The experimental apparatus was instrumented with a suite of state of the art sensor technologies for the continuous and autonomous collection of soil moisture, soil thermal properties, soil and air temperature, relative humidity, and wind speed. This experimental apparatus can be used to generate data under well controlled boundary conditions, allowing for better control and gathering of accurate data at scales of interest not feasible in the field. Induced airflow at several distinct wind speeds over the soil surface resulted in unique behavior of heat and mass transfer during the different evaporative stages.

A protocol for the design and construction of a soil tank interfaced to a small climate controlled wind tunnel to study the effects of atmospheric forcings on evaporation is presented. Both the soil tank and wind tunnel are instrumented with sensor technologies for the continuous in situ measurement of environmental conditions.

Evaporation is directly influenced by the interactions between the atmosphere, land surface and soil subsurface. This work aims to experimentally study ...

A Flow-through Exposure System for Evaluating Suspended Sediments Effects on Aquatic Life

This paper describes the Fish Larvae and Egg Exposure System (FLEES). The flow-through exposure system is used to investigate the effects of suspended sediment on various aquatic species and life stages in the laboratory by using pumps and automating delivery of sediment and water to simulate suspension of sediment. FLEES data are used to develop exposure-response curves between the effects on aquatic organisms and suspended sediment concentrations at the desired exposure duration. The effects data are used to evaluate management practices used to reduce the interactions between aquatic organisms and anthropogenic causes of suspended sediments. The FLEES is capable of generating total suspended solids (TSS) concentrations as low as 30 to as high as 800 mg/L, making this system an ideal choice for evaluating the effects of TSS resulting from many activities including simulating low ambient levels of TSS to evaluating sources of suspended sediments from dredging operations, vessel traffic, freshets, and storms.

A robust and flexible flow-through exposure system designed to maintain sediment in suspension is presented. The system is used to investigate the effects of suspended sediment on various aquatic species and life stages in the laboratory.

This paper describes the Fish Larvae and Egg Exposure System (FLEES). The flow-through exposure system is used to investigate the effects of suspended ...

Evaluating the Effect of Environmental Chemicals on Honey Bee Development from the Individual to Colony Level

The presence of pesticides in the beekeeping environment is one of the most serious problems that impacts the life of a honey bee. Pesticides can be brought back to the beehive after the bees have foraged on flowers that have been sprayed with pesticides. Pesticide contaminated food can be exchanged between workers which then feed larvae and therefore can potentially affect the development of honey bees. Thus, residual pesticides in the environment can become a chronic damaging factor to honey bee populations and gradually lead to colony collapse. In the presented protocol, honey bee feeding methods are described and applied to either an individual honey bee or to a colony. Here, the insect growth regulator (IGR) pyriproxyfen (PPN), which is widely used to control pest insects and is harmful to the development of honey bee larvae and pupae, is used as the pesticide. The presenting procedure can be applied to other potentially harmful chemicals or honeybee pathogens for further studies.

Herein we present a method to feed pesticide contaminated food to both an individual honey bee and a beehive colony. The procedure evaluates the pesticide effect on individual honey bees by in vivo feeding of basic larval diet and also on the natural condition of beehive colony.

The presence of pesticides in the beekeeping environment is one of the most serious problems that impacts the life of a honey bee. Pesticides can be ...

Experimental Column Setup for Studying Anaerobic Biogeochemical Interactions Between Iron (Oxy)Hydroxides, Trace Elements, and Bacteria

Fate and speciation of trace elements (TEs), such as arsenic (As) and mercury (Hg), in aquifers are closely related to physio-chemical conditions, such as redox potential (Eh) and pH, but also to microbial activities that can play a direct or indirect role on speciation and/or mobility. Indeed, some bacteria can directly oxidize As(III) to As(V) or reduce As(V) to As(III). Likewise, bacteria are strongly involved in Hg cycling, either through its methylation, forming the neurotoxin monomethyl mercury, or through its reduction to elemental Hg&#176;. The fates of both As and Hg are also strongly linked to soil or aquifer composition; indeed, As and Hg can bind to organic compounds or (oxy)hydroxides, which will influence their mobility. In turn, bacterial activities such as iron (oxy)hydroxide reduction or organic matter mineralization can indirectly influence As and Hg sequestration. The presence of sulfate/sulfide can also strongly impact these particular elements through the formation of complexes such as thio-arsenates with As or metacinnabar with Hg.
Consequently, many important questions have been raised on the fate and speciation of As and Hg in the environment and how to limit their toxicity. However, due to their reactivity towards aquifer components, it is difficult to clearly dissociate the biogeochemical processes that occur and their different impacts on the fate of these TE.
To do so, we developed an original, experimental, column setup that mimics an aquifer with As- or Hg-iron-oxide rich areas versus iron depleted areas, enabling a better understanding of TE biogeochemistry in anoxic conditions. The following protocol gives step by step instructions for the column set-up either for As or Hg, as well as an example with As under iron and sulfate reducing conditions.

Experimental Column Setup for Studying Anaerobic Biogeochemical Interactions Between Iron OxyHydroxides, Trace Elements, and Bacteria

Fate and speciation of arsenic and mercury in aquifers are closely related to physio-chemical conditions and microbial activity. Here, we present an original experimental column setup that mimics an aquifer and enables a better understanding of trace element biogeochemistry in anoxic conditions. Two examples are presented, combining geochemical and microbiological approaches.

Fate and speciation of trace elements (TEs), such as arsenic (As) and mercury (Hg), in aquifers are closely related to physio-chemical conditions, such as ...

Preparation of DMMTAV and DMDTAV Using DMAV for Environmental Applications: Synthesis, Purification, and Confirmation

Dimethylated thioarsenicals such as dimethylmonothioarsinic acid (DMMTAV) and dimethyldithioarsinic acid (DMDTAV), which are produced by the metabolic pathway of dimethylarsinic acid (DMAV) thiolation, have been recently found in the environment as well as human organs. DMMTAV and DMDTAV can be quantified to determine the ecological effects of dimethylated thioarsenicals and their stability in environmental media. The synthesis method for these compounds is unstandardized, making replicating previous studies challenging. Furthermore, there is a lack of information about storage techniques, including storage of compounds without species transformation. Moreover, because only limited information about synthesis methods is available, there may be experimental difficulties in synthesizing standard chemicals and performing quantitative analysis. The protocol presented herein provides a practically modified synthesis method for the dimethylated thioarsenicals, DMMTAV and DMDTAV, and will help in the quantification of species separation analysis using high performance liquid chromatography in conjunction with inductively coupled plasma mass spectrometry (HPLC-ICP-MS). The experimental steps of this procedure were modified by focusing on the preparation of chemical reagents, filtration methods, and storage.

Preparation of DMMTAV and DMDTAV Using DMAV for Environmental Applications: Synthesis, Purification, and Confirmation

This article presents modified experimental protocols for dimethylmonothioarsinic acid (DMMTAV) and dimethyldithioarsinic acid (DMDTAV) synthesis, inducing dimethylarsinic acid (DMAV) thiolation through mixing of DMAV, Na2S, and H2SO4. The modified protocol provides an experimental guideline, thereby overcoming limitations of the synthesis steps that could have caused experimental failures in quantitative analysis.

Dimethylated thioarsenicals such as dimethylmonothioarsinic acid (DMMTAV) and dimethyldithioarsinic acid (DMDTAV), which are produced by the metabolic ...

Collection and Extraction of Occupational Air Samples for Analysis of Fungal DNA

Traditional methods of identifying fungal exposures in occupational environments, such as culture and microscopy-based approaches, have several limitations that have resulted in the exclusion of many species. Advances in the field over the last two decades have led occupational health researchers to turn to molecular-based approaches for identifying fungal hazards. These methods have resulted in the detection of many species within indoor and occupational environments that have not been detected using traditional methods. This protocol details an approach for determining fungal diversity within air samples through genomic DNA extraction, amplification, sequencing, and taxonomic identification of fungal internal transcribed spacer (ITS) regions. ITS sequencing results in the detection of many fungal species that are either not detected or difficult to identify to species level using culture or microscopy. While these methods do not provide quantitative measures of fungal burden, they offer a new approach to hazard identification and can be used to determine overall species richness and diversity within an occupational environment.

Determining the fungal diversity within an environment is a method utilized in occupational health studies to identify health hazards. This protocol describes DNA extraction from occupational air samples for amplification and sequencing of fungal ITS regions. This approach detects many fungal species that can be overlooked by traditional assessment methods.

Traditional methods of identifying fungal exposures in occupational environments, such as culture and microscopy-based approaches, have several ...

An Experimental Protocol for Studying Mineral Effects on Organic Hydrothermal Transformations

Organic-mineral interactions are widely occurring in hydrothermal environments, such as hot springs, geysers on land, and the hydrothermal vents in the deep ocean. Roles of minerals are critical in many hydrothermal organic geochemical processes. Traditional hydrothermal methodology, which includes using reactors made of gold, titanium, platinum, or stainless-steel, is usually associated with the high cost or undesired metal catalytic effects. Recently, there is a growing tendency for using the cost-effective and inert quartz or fused silica glass tubes in hydrothermal experiments. Here, we provide a protocol for carrying out organic-mineral hydrothermal experiments in silica tubes, and we describe the essential steps in the sample preparation, experimental setup, products separation, and quantitative analysis. We also demonstrate an experiment using a model organic compound, nitrobenzene, to show the effect of an iron-containing mineral, magnetite, on its degradation under a specific hydrothermal condition. This technique can be applied to study complex organic-mineral hydrothermal interactions in a relatively simple laboratory system.

Earth-abundant minerals play important roles in the natural hydrothermal systems. Here, we describe a reliable and cost-effective method for the experimental investigation of organic-mineral interactions under hydrothermal conditions.

Organic-mineral interactions are widely occurring in hydrothermal environments, such as hot springs, geysers on land, and the hydrothermal vents in the ...

Using Caenorhabditis elegans for Studying Trans- and Multi-Generational Effects of Toxicants

Information about toxicities of chemicals are essential in their application and waste management. For chemicals at low concentrations, the long-term effects are very important in judging their consequences in the environment and on human health. In demonstrating long-term influences, effects of chemicals over generations in recent studies provide new insight. Here, we describe protocols for studying effects of chemicals over multiple generations using free-living nematode Caenorhabditis elegans. Two aspects are presented: (1) trans-generational (TG) and (2) multi-generational effect studies, the latter of which is separated to multi-generational exposure (MGE) and multi-generational residual (MGR) effect studies. The TG effect study is robust with a simple purpose to determine whether chemical exposure to parents can result in any residual consequences on offspring. After the effects are measured on parents, sodium hypochlorite solutions are used to kill the parents and keep the offspring so as to facilitate effect measurement on the offspring. The TG effect study is used to determine whether the offspring are affected when their parent is exposed to the pollutants. The MGE and MGR effect study is systematical used to determine whether continuous generational exposure can result in adaptive responses in offspring over generations. Careful pick-up and transfer are used to distinguish generations to facilitate effect measurement on each generation. We also combined protocols to measure locomotion behavior, reproduction, lifespan, biochemical and gene expression changes. Some example experiments are also presented to illustrate the trans- and multi-generational effect studies.

Using Caenorhabditis elegans for Studying Trans- and Multi-Generational Effects of Toxicants

Trans- and multi-generational effects of persistent chemicals are essential in judging their long-term consequences in the environment and on the human health. We provide novel detailed methods for studying trans- and multi-generational effects using free-living nematode Caenorhabditis elegans.

Information about toxicities of chemicals are essential in their application and waste management. For chemicals at low concentrations, the long-term ...

Data Collection on Marine Litter Ingestion in Sea Turtles and Thresholds for Good Environmental Status

The following protocol is intended to respond to the requirements set by the European Union&#39;s Marine Strategy Framework Directives (MSFD) for the D10C3 Criteria reported in the Commission Decision (EU), related to the amount of litter ingested by marine animals. Standardized methodologies for extracting litter items ingested from dead sea turtles along with guidelines on data analysis are provided. The protocol starts with the collection of dead sea turtles and classification of samples according to the decomposition status. Turtle necropsy must be performed in authorized centers and the protocol described here explains the best procedure for gastrointestinal (GI) tract isolation. The three parts of the GI (esophagus, stomach, intestine) should be separated, opened lengthways and contents filtered using a 1 mm mesh sieve. The article describes the classification and quantification of ingested litter, classifying GI contents into seven different categories of marine litter and two categories of natural remains. The quantity of ingested litter should be reported as total dry mass (weight in grams, with two decimal places) and abundance (number of items). The protocol proposes two possible scenarios to achieve the Good Environmental Status (GES). First: &#34;There should be less than X% of sea turtles having Y g or more plastic in the GI in samples of 50-100 dead turtles from each sub-region&#34;, where Y is the average weight of plastic ingested and X% is the percentage of sea turtles with more weight (in grams) of plastic than Y. The second one, which considers the food remain versus plastic as a proxy of individual health, is: &#34;There should be less than X% of sea turtles having more weight of plastic (in grams) than food remains in the GI in samples of 50-100 dead turtles from each sub-region&#34;.

The protocol focuses on the collection of sea turtle samples, describing all the steps from the animal recovery and necropsy to the classification and quantification of ingested marine litter. Moreover, the representative results show how to use the collected data to elaborate the possible thresholds for Good Environmental Status.

The following protocol is intended to respond to the requirements set by the European Union&#39;s Marine Strategy Framework Directives (MSFD) for the ...

Using Tg(Vtg1:mcherry) Zebrafish Embryos to Test the Estrogenic Effects of Endocrine Disrupting Compounds

There are many endocrine disrupting compounds (EDC) in the environment, especially estrogenic substances. The detection of these substances is difficult due to their chemical diversity; therefore, increasingly more effect-detecting methods are used, such as estrogenic effect-sensitive biomonitor/bioindicator organisms. These biomonitoring organisms include several fish models. This protocol covers the use of zebrafish Tg(vtg1: mCherry) transgenic line as a biomonitoring organism, including the propagation of fish and the treatment of embryos, with an emphasis on the detection, documentation, and evaluation of fluorescent signals induced by EDC. The goal of the work is the demonstration of the use of the Tg(vtg1: mCherry) transgenic line embryos to detect estrogenic effects. This work documents the use of transgenic zebrafish embryos Tg(vtg1: mCherry) for the detection of estrogenic effects by testing two estrogenic substances, &#945;- and &#946;-zearalenol. The described protocol is only a basis for designing assays; the test method can be varied according to the test endpoints and the samples. Moreover, it can be combined with other assay methods, thereby facilitating the future use of the transgenic line.

Using TgVtg1:mcherry Zebrafish Embryos to Test the Estrogenic Effects of Endocrine Disrupting Compounds

Present here is a detailed protocol for the use of zebrafish embryos Tg(vtg1: mCherry) for the detection of estrogenic effects. The protocol covers the propagation of the fish and treatment of embryos, and emphasizes the detection, documentation, and the evaluation of fluorescent signals induced by endocrine disrupting compounds (EDC).

There are many endocrine disrupting compounds (EDC) in the environment, especially estrogenic substances. The detection of these substances is difficult ...