Name: experimental protocol for detecting mitochondrial function in hepatocytes exposed to organochlorine pesticides
Uploaded: 2020-09-16T12:30:00
Description: Watch this Scientific Journal Video about Experimental Protocol for Detecting Mitochondrial Function in Hepatocytes Exposed to Organochlorine Pesticides at JoVE.com

This work was supported by the National Natural Science Foundation of China (Grant Nos. 81573174, 81570574); the Outstanding Youth Fund of Jiangsu Province (SBK2014010296); the Research Project of Chinese Ministry of Education (213015A); the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD), the Flagship Major Development of Jiangsu Higher Education Institutions; and the Open Project Program of the State Key Laboratory of Environmental Chemistry and Ecotoxicology (KF2015-01).

All experiments and the experiment protocols were performed in accordance with relevant guidelines and regulations and approved by the local Ethical Committee of Nanjing Medical University.
1. Mitochondrial ultrastructure by TEM
<ol>
	<li>Collecting HepG2 cells
	<ol>
		<li>Seed HepG2 cells in 100 mm dishes. Store at 37 &#176;C and 5% CO2.</li>
		<li>Digest cells with 0.25% EDTA in 1.5 mLEP tube.</li>
		<li>Centrifuge at 1000 x g for 3 min at room temperature (RT). Discard...

<ol>
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Critical to the success of the detection protocol is the use of a variety of experimental methods that have been covered the study from phenotype to mechanism. In this study, HepG2 cells were cultured in DMEM with penicillin and streptomycin and 10% fetal bovine serum. When cells reached 40-50% con&#64258;uence, &#946;-HCH (0, 10, 100 ng/mL) were added and incubated for 24 h. We firstly used TEM which showed the ultrastructural changes in hepatocyte caused by the representative OCPs, &#946;-HCH, showing the impairment of...

The effects of organochlorine pesticides (OCPs) on health, e.g. reproductive interference, immunological toxicity, metabolic changes have been previously studied1,2,3. The methods to detect cellular metabolism and find out mitochondrial dysfunction have enabled scientists to understand the role of mitochondrial function (i.e., mitochondrial STAT3 levels, lactate, pyruvate, lactate-to-pyruvate ratio, coenzyme Q10, mitochondrial proton leak, bioenergetics, biogenesis, and dynamics) in areas such as aging, obesity, diabetes, cardiovascular function, cancer, and safety toxicity4,5,6,7. In this paper, we describe the methods on assessing mitochondrial dysfunction caused by OCPs.
We exposed HepG2 cells to &#946;-hexachlorocyclohexane (&#946;-HCH), one representative OCPs, for 24 h at a dose equivalent to internal exposure of human. Firstly, TEM was applied to observe the ultrastructure of hepatocytes, such as nuclei, mitochondria and endoplasmic reticulum8. Compared with ordinary microscopes, TEM enables to explore the 2D and 3D ultra-structure of cells and cell components (cell lines or tissue), the morphology, chemical composition, as well as function of natural or artificial materials that play a pivotal role in modern science and technology. Mitochondrial function was further evaluated by mitochondrial fluorescence intensity, adenosine 5&#39;-triphosphate (ATP) levels, oxygen consumption rate (OCR) and mitochondrial membrane potential (MMP)in HepG2 cells incubated with &#946;-HCH. Mito-tracker green is a mitochondria green fluorescent probe that can be used for live cell mitochondrial-specific fluorescent staining. The mitochondria in hepatocytes were stained by mito-tracker green solution and mitochondrial fluorescence intensity, number and pattern were observed with a confocal microscopy9. Mitochondrial green fluorescent probe can be used to stain live cells. Compared with rhodamine 123 or JC-1, mitochondrial green fluorescent probe does not depend on mitochondrial membrane potential for mitochondrial staining. ATP levels were determined by a luciferase-luciferin kit and normalized by protein concentration. ATP assay kit can be used to detect ATP levels in common solutions, cells or tissues. This kit is based on firefly luciferase catalyzed by fluorescein to generate fluorescence, when ATP is required to provide energy. When the firefly luciferase and fluorescein are excessive, in a certain concentration range, the generation of fluorescence is proportional to the concentration of ATP. In addition, this kit has been specially designed to optimize the chemiluminescence of ATP. ATP, as the most important energy molecules, plays an important role in the various physiological or pathological processes of cells. Changes in ATP levels can reflect defects in cell function, especially mitochondrial energy production. Usually under apoptosis, necrosis or in some toxic state, cellular ATP levels reduced 10. MMPs assay kit with JC-1 is a kit that uses JC-1 as a fluorescent probe to detect cells, tissues or purified MMPs quickly and sensitively. It can be used for early detection of apoptosis. The cationic dye JC-1 is a fluorescent probe used to detect the MMP which can be analyzed under flow cytometry indicated by changes of green and red fluorescence ratio. When the MMP is high, JC-1 is aggregated in the matrix of the mitochondria to form a polymer (J-aggregates), which produces red fluorescence. When the MMP is low, JC-1 cannot accumulate, and forms monomer which produces green fluorescence11. So the ratio of red and green fluorescence can reflect the level of MMP. The OCR of cells is a crucial indicator of normal cellular function12. It is regarded as a parameter to research mitochondrial function. Cell mito stress test kit provides a stable method for analyzing key parameters of mitochondrial function. The kit provides quality control and predictive reagents as well as a standard method for performing cell mitochondrial stress test. It can be used to detect all cell types, including primary cells, cell lines, suspended cells, and also for islets, nematodes, yeasts and isolated mitochondria.
OCR measurement can provide valuable insight into the physiological status or alterations of cells. It was determined with an extracellular flux analyzer to detect breathing baseline, proton leak, maximal respiratory, ATP turnover and reserve capacity. In brief, after baseline measurements of OCR, OCR was detected after sequentially adding to oligomycin (ATP Coupler), FCCP (mitochondrial oxidative phosphorylation uncoupler) and antimycin A/rotenone (an inhibitor of oxygen consumption)per well.
In an effort to facilitate the development of more specific protocol for detecting mitochondrial function in hepatocytes in vitro, we present here experiments by TEM, confocal microscopy, luminometer, flow cytometry and extracellular flux analyzer with future application in studying mitochondria damage related adverse outcomes.

<table border="0" cellpadding="0" cellspacing="0" style="width:756px;" width="755">
	<tbody>
		<tr height="21">
			<td>Transmission electron microscope&#160;</td>
			<td>FEI</td>
			<td>Tecnai G2 Spirit Bio TWIN</td>
			<td>High-contrast, high-resolution imaging, Low-dose observation and imaging, Low-temperature observation, Outstanding analytical performance, Automation for convenience and performance</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:205px;">Mito-Tracker Green</td>
			<td style="width:69px;">Beyotime</td>
			<td style="width:161px;">C1048</td>
			<td style="width:320px;">Mito-Tracker Green is a mitochondrial green fluorescent probe that can be used for live cell mitochondrial-specific fluorescent staining.</td>
		</tr>
		<tr height="21">
			<td height="105" style="height:105px;width:205px;">Laser scanning confocal microscope</td>
			<td style="width:69px;">Zeiss</td>
			<td style="width:161px;">700B</td>
			<td style="width:320px;">The design is compact, stable, light path is the shortest, high light precision, creative technology and sophisticated scanning technology together to&#160; produce a perfect 3-dimensional specimen image.</td>
		</tr>
		<tr height="147">
			<td height="147" style="height:147px;width:205px;">Enhanced ATP Assay Kit</td>
			<td style="width:69px;">Beyotime</td>
			<td style="width:161px;">S0027</td>
			<td style="width:320px;">Enhanced ATP Assay Kit can be used to detect ATP (adenosine 5&#39;-triphosphate) levels in common solutions, cells or tissues. Cells and tissue samples can be split to complete the sample preparation, detection sensitivity up to 0.1nmol / L, chemiluminescence can be sustained for 30 minutes.</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:205px;">Luminometer</td>
			<td style="width:69px;">Berthold</td>
			<td style="width:161px;">Centro LB 960</td>
			<td style="width:320px;">Luminometer is chemiluminescence detector, the test sample itself can be light, do not need to stimulate. Luminometer is the instrument that detects chemiluminescence.</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:205px;">BCA Protein Assay Kit</td>
			<td style="width:69px;">Beyotime</td>
			<td style="width:161px;">P0012</td>
			<td style="width:320px;">BCA Protein Assay Kit is one of the most commonly used methods for detecting protein concentrations.</td>
		</tr>
		<tr height="21">
			<td height="42" style="height:42px;width:205px;">Multimode reader</td>
			<td style="width:69px;">TECAN</td>
			<td style="width:161px;">InfiniteM200</td>
			<td style="width:320px;">Multimode reader be used to detect protein consentration.</td>
		</tr>
	</tbody>
</table>

experimental protocol for detecting mitochondrial function in hepatocytes exposed to organochlorine pesticides

This paper presents detailed methods on detecting hepatic mitochondrial function for a better understanding the cause of metabolic disorders caused by environmental organochlorine pesticides (OCPs) in hepatocytes. HepG2 cells were exposed to &#946;-hexachlorocyclohexane (&#946;-HCH) for 24 h at an equivalent dose of internal exposure in general population. Ultrastructure in hepatocytes was examined by transmission electron microscopy (TEM) to show the damage of mitochondria. Mitochondrial function was further evaluated by mitochondrial fluorescence intensity, adenosine 5'-triphosphate (ATP) levels, oxygen consumption rate (OCR) and mitochondrial membrane potential (MMP) in HepG2 cells incubated with &#946;-HCH. The mitochondria fluorescence intensity after stained by mitochondrial green fluorescent probe was observed with a fluorescence microscopy. The luciferin-luciferase reaction was used to determine ATP levels. The MMP was detected by the cationic dye JC-1 and analyzed under flow cytometry. OCR was measured with an extracellular flux analyzer. In summary, these protocols were used in detecting mitochondrial function in hepatocytes with to investigate mitochondria damages.

The mitochondria cristae of HepG2 cells exposed to &#946;-HCH were markedly damaged. Scattered mitochondria were mildly to markedly expanded, irregularly shaped, and mitochondrial ridge disappeared with relatively abnormal mitochondrial architecture (Figure 1).
Average mitochondrial green fluorescence intensity, which represents the mitochondria, decreased in HepG2 cells exposed to &#946;-HCH (<stro...

Watch this Scientific Journal Video about Experimental Protocol for Detecting Mitochondrial Function in Hepatocytes Exposed to Organochlorine Pesticides at JoVE.com

Experimental Protocol for Detecting Mitochondrial Function in Hepatocytes Exposed to Organochlorine Pesticides

Understanding the influence of environmental organochlorine pesticides (OCPs) on mitochondrial function in hepatocytes is important in exploring the mechanism of OCPs causing metabolic disorders. This paper presents detailed methods on detecting hepatic mitochondrial function.

This paper presents detailed methods on detecting hepatic mitochondrial function for a better understanding the cause of metabolic disorders caused by ...

It's a messer that call answer a key question that you have in also a function of field such as ATP level and the oxygen consumption rates. The new or the one page old, this technique is that it's easy to perform and it's a lot for a special evaluation of cellular mitochondrial function. To start this experiment, seed 20, 000 HepG2 cells in a glass bottom Petri dish.Add beta-hexachlorcyclohexane or B-HCH in incubator at 37 degrees Celsius and five percent CO2 for 24 hours. Prepare one millimolar mitochondrial green fluorescence probe solution by adding anhydrous DMSO to DMEM cell culture medium. Then add one milliliter per dish of this solution to the cells in glass bottom Petri dishes.And incubate at 37 degrees Celsius for 45 minutes. After incubation, remove the mitochondrial green fluorescent probe solution from the cells. Add one milliliter per dish of freshly prepared at 37 degrees Celsius DMEM cell culture medium.To detect green fluorescence in mitochondria, observe the cells under a confocal microscope. To evaluate levels of cellular ATP, seed to 20, 000 HepG2 cells in six well plates. Add beta-HCH and incubate at 37 degrees Celsius for 24 hours.Add 200 microliters of lysis buffer to the cells in each well. Centrifuge at 12, 000 times G for five minutes at four degrees Celsius, and proceed with collecting supernatant as described in the text protocol. Add 100 microliters ATP detection buffer to the plate.Add 100 microliters of collected cell supernatant to a 96 well plate at room temperature and proceeded to detect cellular ATP by a luminometer as described in the text protocol. For assessment of mitochondrial membrane potential, grow HepG2 cells in six well plates with the addition of beta-HCH, as previously described. Collect the cells by digesting them with 0.5 milliliters 0.25%EDTA for one minute at 37 degrees Celsius.Add one milliliter DMEM to stop digestion and transfer the digested cells to 1.5 milliliter tubes. Centrifuge the tubes at 1000 times G for three minutes, and then discard the supernatant. Dilute the cell pellet with 0.5 milliliters of cell culture medium and 0.5 milliliters JC1 mitochondrial membrane potential dye.And incubate for 20 minutes at 37 degrees Celsius. Next, centrifuge the tubes at 600 times G for three minutes at four degrees Celsius, and then wash the cell pellet according to the text protocol. After centrifuging the washed pellet, remove the supernatant.And re-suspend the pellet in 0.5 milliliters of JC1 dyeing buffer. Analyze the JC1 stained cells via flow cytometry to detect green and red fluorescence. When the JC1 monomer is detected, set the excitation light to 490 nanometers and the emission light to 530 nanometers.When the JC1 polymer is detected, set the excitation light to 525 nanometers and the emission light to 590 nanometers. To analyze the oxygen consumption rate, seed HepG2 cells in a 96 well cell culture plate in a density of 4, 500 cells per 100 microliters per well. After 24 hours of incubation at 37 degrees Celsius, make sure that the cells in each well are covered with medium.Before running the OCR software, load the microplate with cartridge and the cell culture plate into an extracellular flux analyzer as described in the text protocol. Open the OCR software and in the apps drop down menu, choose cell mito stress test kit, and click on the start app button. Next, click on the run stress test button.When the cell stress test screen appears, enter the number of cells seeding per well in the cell seeding number box and the average OCR in the average at basal cell OCR box. Enter the final working concentration for each reagent and then inject the reagents. Click on the next button.When the group info screen appears, assign a group to unassigned wells by choosing a color and giving a name. Then click on the appropriate wells. Click the next button and in the stress test injection layout screen that appears, click on start to run the stress test on the analyzer.After the completed run, follow the prompts in the software and then remove and discard the cartridge and cell plate. Average intensity of mitochondrial green fluorescent staining decreased in HepG2 cells exposed to beta-HCH. This shows that there is a decrease in mitochondrial number and increase in damaged mitochondria consistent with the increase in pesticide concentration.Furthermore, ATP levels in HepG2 cells decreased with the increased concentrations of beta-HCH exposure, showing the decreased function of mitochondria in these cells. After JC1 staining for mitochondrial membrane potential, or MMP, flow cytometer showed high red green JC1 fluorescence in intact HepG2 cells. This was due to the presence of red fluorescent JC1 aggregates, which are a sign of high MMP.In cells treated with beta-HCH, red green JC1 fluorescence decreased due to a presence of green fluorescent JC1 monomers, a sign of low MMP. Finally, oxygen consumption rate also decreased with the increased concentrations of beta-HCH exposure, further showing that this pesticide impairs proper mitochondrial function. Oh, well, attempt to this procedure, it's important though, to remember to see that cells as appropriate to test it.After its development, this definitely paves a way for researches in the field of fundamental function to explore relevant organisms in the medical role associated with it. After watching this video, you should have a good understanding of how to detect an amount or quality, capacity, now member or potential under spoutage sheet function.

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Environment

Experimental Protocol for Manipulating Plant-induced Soil Heterogeneity

Coexistence theory has often treated environmental heterogeneity as being independent of the community composition; however biotic feedbacks such as plant-soil feedbacks (PSF) have large effects on plant performance, and create environmental heterogeneity that depends on the community composition. Understanding the importance of PSF for plant community assembly necessitates understanding of the role of heterogeneity in PSF, in addition to mean PSF effects. Here, we describe a protocol for manipulating plant-induced soil heterogeneity. Two example experiments are presented: (1) a field experiment with a 6-patch grid of soils to measure plant population responses and (2) a greenhouse experiment with 2-patch soils to measure individual plant responses. Soils can be collected from the zone of root influence (soils from the rhizosphere and directly adjacent to the rhizosphere) of plants in the field from conspecific and heterospecific plant species. Replicate collections are used to avoid pseudoreplicating soil samples. These soils are then placed into separate patches for heterogeneous treatments or mixed for a homogenized treatment. Care should be taken to ensure that heterogeneous and homogenized treatments experience the same degree of soil disturbance. Plants can then be placed in these soil treatments to determine the effect of plant-induced soil heterogeneity on plant performance. We demonstrate that plant-induced heterogeneity results in different outcomes than predicted by traditional coexistence models, perhaps because of the dynamic nature of these feedbacks. Theory that incorporates environmental heterogeneity influenced by the assembling community and additional empirical work is needed to determine when heterogeneity intrinsic to the assembling community will result in different assembly outcomes compared with heterogeneity extrinsic to the community composition.

Understanding the role of environmental heterogeneity in species coexistence has typically focused on types of heterogeneity that are extrinsic to the community&#8217;s species composition. We provide novel detailed methods for creating soil heterogeneity treatments using soils subject to plant-soil feedback conditioning, or heterogeneity intrinsic to the community composition.

Coexistence theory has often treated environmental heterogeneity as being independent of the community composition; however biotic feedbacks such as ...

A Protocol for Conducting Rainfall Simulation to Study Soil Runoff

Rainfall is a driving force for the transport of environmental contaminants from agricultural soils to surficial water bodies via surface runoff. The objective of this study was to characterize the effects of antecedent soil moisture content on the fate and transport of surface applied commercial urea, a common form of nitrogen (N) fertilizer, following a rainfall event that occurs within 24&#160;hr&#160;after fertilizer application. Although urea is assumed to be readily hydrolyzed to ammonium and therefore not often available for transport, recent studies suggest that urea can be transported from agricultural soils to coastal waters where it is implicated in harmful algal blooms. A rainfall simulator was used to apply a consistent rate of uniform rainfall across packed soil boxes that had been prewetted to different soil moisture contents. By controlling rainfall and soil physical characteristics, the effects of antecedent soil moisture on urea loss were isolated. Wetter soils exhibited shorter time from rainfall initiation to runoff initiation, greater total volume of runoff, higher urea concentrations in runoff, and greater mass loadings of urea in runoff. These results also demonstrate the importance of controlling for antecedent soil moisture content in studies designed to isolate other variables, such as soil physical or chemical characteristics, slope, soil cover, management, or rainfall characteristics. Because rainfall simulators are designed to deliver raindrops of similar size and velocity as natural rainfall, studies conducted under a standardized protocol can yield valuable data that, in turn, can be used to develop models for predicting the fate and transport of pollutants in runoff.

A rainfall simulator was used to apply a consistent rate of uniform rainfall to packed soil boxes in a study of the fate and transport of urea, a nonpoint source environmental contaminant. Under uniform soil and rainfall conditions, antecedent soil moisture content exerted strong control over urea loss in surface runoff.

Rainfall is a driving force for the transport of environmental contaminants from agricultural soils to surficial water bodies via surface runoff. The ...

LC-MS Analysis of Human Platelets as a Platform for Studying Mitochondrial Metabolism

Perturbed mitochondrial metabolism has received renewed interest as playing a causative role in a range of diseases. Probing alterations to metabolic pathways requires a model in which external factors can be well controlled, allowing for reproducible and meaningful results. Many studies employ transformed cellular models for these purposes; however, metabolic reprogramming that occurs in many cancer cell lines may introduce confounding variables. For this reason primary cells are desirable, though attaining adequate biomass for metabolic studies can be challenging. Here we show that human platelets can be utilized as a platform to carry out metabolic studies in combination with liquid chromatography-tandem mass spectrometry analysis. This approach is amenable to relative quantification and isotopic labeling to probe the activity of specific metabolic pathways. Availability of platelets from individual donors or from blood banks makes this model system applicable to clinical studies and feasible to scale up. Here we utilize isolated platelets to confirm previously identified compensatory metabolic shifts in response to the complex I inhibitor rotenone. More specifically, a decrease in glycolysis is accompanied by an increase in fatty acid oxidation to maintain acetyl-CoA levels. Our results show that platelets can be used as an easily accessible and medically relevant model to probe the effects of xenobiotics on cellular metabolism.

Here we show isolated human platelets can be used as an accessible ex vivo model to study metabolic adaptations in response to the complex I inhibitor rotenone. This approach employs isotopic tracing and relative quantification by liquid chromatography-mass spectrometry and can be applied to a variety of study designs.

Perturbed mitochondrial metabolism has received renewed interest as playing a causative role in a range of diseases. Probing alterations to metabolic ...

Characterization and Application of Passive Samplers for Monitoring of Pesticides in Water

Five different water passive samplers were calibrated under laboratory conditions for measurement of 124 legacy and current used pesticides. This study provides a protocol for the passive sampler preparation, calibration, extraction method and instrumental analysis. Sampling rates (RS) and passive sampler-water partition coefficients (KPW) were calculated for silicone rubber, polar organic chemical integrative sampler POCIS-A, POCIS-B, SDB-RPS and C18 disk. The uptake of the selected compounds depended on their physicochemical properties, i.e., silicone rubber showed a better uptake for more hydrophobic compounds (log octanol-water partition coefficient (KOW) &#62; 5.3), whereas POCIS-A, POCIS-B and SDB-RPS disk were more suitable for hydrophilic compounds (log KOW &#60; 0.70).

A protocol about the characterization and application of five different passive sampling devices is presented.

Five different water passive samplers were calibrated under laboratory conditions for measurement of 124 legacy and current used pesticides. This study ...

Experimental Protocol for Biodiesel Production with Isolation of Alkenones as Coproducts from Commercial Isochrysis Algal Biomass

The need to replace petroleum fuels with alternatives from renewable and more environmentally sustainable sources is of growing importance. Biomass-derived biofuels have gained considerable attention in this regard, however first generation biofuels from edible crops like corn ethanol or soybean biodiesel have generally fallen out of favor. There is thus great interest in the development of methods for the production of liquid fuels from domestic and superior non-edible sources. Here we describe a detailed procedure for the production of a purified biodiesel from the marine microalgae Isochrysis. Additionally, a unique suite of lipids known as polyunsaturated long-chain alkenones are isolated in parallel as potentially valuable coproducts to offset the cost of biodiesel production. Multi-kilogram quantities of Isochrysis are purchased from two commercial sources, one as a wet paste (80% water) that is first dried prior to processing, and the other a dry milled powder (95% dry). Lipids are extracted with hexanes in a Soxhlet apparatus to produce an algal oil (&#34;hexane algal oil&#34;) containing both traditional fats (i.e., triglycerides, 46-60% w/w) and alkenones (16-25% w/w). Saponification of the triglycerides in the algal oil allows for separation of the resulting free fatty acids (FFAs) from alkenone-containing neutral lipids. FFAs are then converted to biodiesel (i.e., fatty acid methyl esters, FAMEs) by acid-catalyzed esterification while alkenones are isolated and purified from the neutral lipids by crystallization. We demonstrate that biodiesel from both commercial Isochrysis biomasses have similar but not identical FAME profiles, characterized by elevated polyunsaturated fatty acid contents (approximately 40% w/w). Yields of biodiesel were consistently higher when starting from the Isochrysis wet paste (12% w/w vs. 7% w/w), which can be traced to lower amounts of hexane algal oil obtained from the powdered Isochrysis product.

Experimental Protocol for Biodiesel Production with Isolation of Alkenones as Coproducts from Commercial Isochrysis Algal Biomass

Detailed methods are presented for the production of biodiesel along with the co-isolation of alkenones as valuable coproducts from commercial Isochrysis microalgae.

The need to replace petroleum fuels with alternatives from renewable and more environmentally sustainable sources is of growing importance. ...

Experimental Protocol for Detecting Cyanobacteria in Liquid and Solid Samples with an Antibody Microarray Chip

Global warming and eutrophication make some aquatic ecosystems behave as true bioreactors that trigger rapid and massive cyanobacterial growth; this has relevant health and economic consequences. Many cyanobacterial strains are toxin producers, and only a few cells are necessary to induce irreparable damage to the environment. Therefore, water-body authorities and administrations require rapid and efficient early-warning systems providing reliable data to support their preventive or curative decisions. This manuscript reports an experimental protocol for the in-field detection of toxin-producing cyanobacterial strains by using an antibody microarray chip with 17 antibodies (Abs) with taxonomic resolution (CYANOCHIP). Here, a multiplex fluorescent sandwich microarray immunoassay (FSMI) for the simultaneous monitoring of 17 cyanobacterial strains frequently found blooming in freshwater ecosystems, some of them toxin producers, is described. A microarray with multiple identical replicates (up to 24) of the CYANOCHIP was printed onto a single microscope slide to simultaneously test a similar number of samples. Liquid samples can be tested either by direct incubation with the antibodies (Abs) or after cell concentration by filtration through a 1- to 3-&#956;m filter. Solid samples, such as sediments and ground rocks, are first homogenized and dispersed by a hand-held ultrasonicator in an incubation buffer. They are then filtered (5 - 20 &#956;m) to remove the coarse material, and the filtrate is incubated with Abs. Immunoreactions are revealed by a final incubation with a mixture of the 17 fluorescence-labeled Abs and are read by a portable fluorescence detector. The whole process takes around 3 h, most of it corresponding to two 1-h periods of incubation. The output is an image, where bright spots correspond to the positive detection of cyanobacterial markers.

Experimental Protocol for Detecting Cyanobacteria in Liquid and Solid Samples with an Antibody Microarray Chip

The presence of cyanobacterial toxins in fresh water reservoirs for human consumption is a major concern for water management authorities. To evaluate the risk of water contamination, this article describes an protocol for the in-field detection of cyanobacterial strains in liquid and solid samples by using an antibody microarray chip.

Global warming and eutrophication make some aquatic ecosystems behave as true bioreactors that trigger rapid and massive cyanobacterial growth; this has ...

Extraction of Organochlorine Pesticides from Plastic Pellets and Plastic Type Analysis

Plastic resin pellets, categorized as microplastics (&#8804;5 mm in diameter), are small granules that can be unintentionally released to the environment during manufacturing and transport. Because of their environmental persistence, they are widely distributed in the oceans and on beaches all over the world. They can act as a vector of potentially toxic organic compounds (e.g., polychlorinated biphenyls) and might consequently negatively affect marine organisms. Their possible impacts along the food chain are not yet well understood. In order to assess the hazards associated with the occurrence of plastic pellets in the marine environment, it is necessary to develop methodologies that allow for rapid determination of associated organic contaminant levels. The present protocol describes the different steps required for sampling resin pellets, analyzing adsorbed organochlorine pesticides (OCPs) and identifying the plastic type. The focus is on the extraction of OCPs from plastic pellets by means of a pressurized fluid extractor (PFE) and on the polymer chemical analysis applying Fourier Transform-InfraRed (FT-IR) spectroscopy. The developed methodology focuses on 11 OCPs and related compounds, including dichlorodiphenyltrichloroethane (DDT) and its two main metabolites, lindane and two production isomers, as well as the two biologically active isomers of technical endosulfan. This protocol constitutes a simple and rapid alternative to existing methodology for evaluating the concentration of organic contaminants adsorbed on plastic pieces.

Microplastics act as vector of potentially toxic organic contaminants with unpredictable effects. This protocol describes an alternative methodology for assessing the levels of organochlorine pesticides adsorbed on plastic pellets and identifying the polymer chemical structure. The focus is on pressurized fluid extraction and attenuated total reflectance Fourier transform infrared spectroscopy.

Plastic resin pellets, categorized as microplastics (&#8804;5 mm in diameter), are small granules that can be unintentionally released to the environment ...

Video Tracking Protocol to Screen Deterrent Chemistries for Honey Bees

The European honey bee, Apis mellifera L., is an economically and agriculturally important pollinator that generates billions of dollars annually. Honey bee colony numbers have been declining in the United States and many European countries since 1947. A number of factors play a role in this decline, including the unintentional exposure of honey bees to pesticides. The development of new methods and regulations are warranted to reduce pesticide exposures to these pollinators. One approach is the use of repellent chemistries that deter honey bees from a recently pesticide-treated crop. Here, we describe a protocol to discern the deterrence of honey bees exposed to select repellent chemistries. Honey bee foragers are collected and starved overnight in an incubator 15 h prior to testing. Individual honey bees are placed into Petri dishes that have either a sugar-agarose cube (control treatment) or sugar-agarose-compound cube (repellent treatment) placed into the middle of the dish. The Petri dish serves as the arena that is placed under a camera in a light box to record the honey bee locomotor activities using video tracking software. A total of 8 control and 8 repellent treatments were analyzed for a 10 min period with each treatment was duplicated with new honey bees. Here, we demonstrate that honey bees are deterred from the sugar-agarose cubes with a compound treatment whereas honey bees are attracted to the sugar-agarose cubes without an added compound.

The loss of honey bee colonies presents a challenge to crop pollination services. Current pollinator protection practices warrant an alternative approach to minimize the contact of honey bees to harmful pesticides using repellent chemistries. Here, we provide detailed methods for a visual tracking protocol to screen deterrents for bees.

The European honey bee, Apis mellifera L., is an economically and agriculturally important pollinator that generates billions of dollars annually. Honey ...

Experimental Protocol for Examining Behavioral Response Profiles in Larval Fish: Application to the Neuro-stimulant Caffeine

Fish models and behaviors are increasingly used in the biomedical sciences; however, fish have long been the subject of ecological, physiological and toxicological studies. Using automated digital tracking platforms, recent efforts in neuropharmacology are leveraging larval fish locomotor behaviors to identify potential therapeutic targets for novel small molecules. Similar to these efforts, research in the environmental sciences and comparative pharmacology and toxicology is examining various behaviors of fish models as diagnostic tools in tiered evaluation of contaminants and real-time monitoring of surface waters for contaminant threats. Whereas the zebrafish is a popular larval fish model in the biomedical sciences, the fathead minnow is a common larval fish model in ecotoxicology. Unfortunately, fathead minnow larvae have received considerably less attention in behavioral studies. Here, we develop and demonstrate a behavioral profile protocol using caffeine as a model neurostimulant. Though photomotor responses of fathead minnows were occasionally affected by caffeine, zebrafish&#160;were markedly more sensitive for photomotor and locomotor endpoints, which responded at environmentally relevant levels. Future studies are needed to understand comparative behavioral sensitivity differences among fish with age and time of day, and to determine whether similar behavioral effects would occur in nature and be indicative of adverse outcomes at the individual or population levels of biological organization.

Here, we present a protocol to examine larval zebrafish and fathead minnow locomotor activities and photomotor responses (PMR) using an automated tracking software. When incorporated in common toxicology bioassays, analyses of these behaviors provide a diagnostic tool to examine chemical bioactivity. This protocol is described using caffeine, a model neurostimulant.

Fish models and behaviors are increasingly used in the biomedical sciences; however, fish have long been the subject of ecological, physiological and ...

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 ...