We gratefully thank Prof. Colin Jackson for the support with purified cofactor F420. This research was supported by Tyrolean science fund (TWF) and the Universit&#228;t Innsbruck (Publikationsfonds). We greatly acknowledge the support of GPS, HK, SB, GG, and HB.

NOTE: Extraction and analysis of cofactor F420 is a three-step process including sample lysis, cofactor pre-purification via solid-phase extraction (SPE), and cofactor detection via ion-paired-RP-HPLC (IP-RP-HPLC) with fluorescence detection. Prior to starting, prepare the materials and reagents as stated in Table 1.
1. Sample lysis
<ol>
	<li>Add up to 5 g of sample to appropriate tubes (e.g., 50 mL conical tubes).</li>
	<li>Add 5 mL of the lysis buffer (2x stock solution, Table 1) to the samples.</li>
	<li>Bring to a final volume of 10 mL with distilled water to reach a final concentration of 0.5 g&#183;mL-1.</li>
	<li>Vortex the diluted samples for 20 s.</li>
	<li>Autoclave for 30 min at 121 &#176;C.</li>
	<li>For dry samples like forest soil, bring to a final volume of 20 mL with distilled water after autoclaving and vortex the diluted sample. 
	&#8203;CAUTION: Temperature increase during autoclaving might cause tubes to burst.</li>
</ol>
2. Pre-purification of the cofactor F 420 via solid-phase extraction (SPE)
NOTE: All steps of SPE are conducted at room temperature
<ol>
	<li>Cool down the samples to room temperature.</li>
	<li>Centrifuge the autoclaved samples for 5 min at 11,000 x g.</li>
	<li>Prepare 5 mL SPE columns filled with 100 mg of weak anion mixed-mode polymeric sorbent.</li>
	<li>Condition the anion exchanger with 3 mL of methanol (condition solution, Table 1).</li>
	<li>Equilibrate the anion exchanger with 3 mL of distilled water (equilibration solution, Table 1).</li>
	<li>Load up to 9.0 mL of the supernatant from the centrifuged lysate onto the SPE column.</li>
	<li>Wash away impurities with 5 mL of 25 mM ammonium acetate (SPE wash solution 1, Table 1).</li>
	<li>Wash away&#160;impurities with 5 mL of methanol (SPE wash solution 2, Table 1).</li>
	<li>Elute the cofactor F420 in 1.0 mL of elution buffer (Table 1). 
	NOTE: Prepare fresh elution buffer. Due to the applied vacuum and the high vapor pressure of the elution buffer, elution volumes might differ from sample to sample. In order to secure the same final volume in all the samples, it is recommended to weigh the collection vessels before and after elution and calculate the effective elution volume. Balance the differences by the addition of elution buffer.</li>
</ol>
3. Detection of the cofactor F420
<ol>
	<li>Set the oven to 40 &#176;C and fluorescence detector to 420 nm extinction-wavelength and 470 nm emission-wavelength. Achieve separation via gradient mode using mobile phases A and B (Table 1): 0-3 min: 26% B; 3-24 min: 26%-50% B; 24-25 min: 50% B; 25-27 min: 50%-26% B; 27-35 min: 26% B at a flow rate of 0.75 mL&#183;min-1. 
	NOTE: Guarantee equilibration of column conditions prior to injecting samples by flushing the column at least with 3 column volumes of 74% mobile phase A and 26% mobile phase B (Table 1).
	<ol>
		<li>Filter the eluted samples from the SPE into HPLC vials using a PTFE filter with a pore size of 0.22 &#181;m. 
		NOTE: PTFE filters with a pore size of 0.22 &#181;m are recommended.</li>
		<li>Inject 50 &#181;L of the eluted sample onto the HPLC system to analyze the cofactor F420 composition and concentration. 
		NOTE: As no quantitative standard is used in this protocol, samples and variants have to be compared by peak area.</li>
	</ol>
	</li>
</ol>

<ol>
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P., Daniels, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Presence+of+F420-dependent+glucose-6-phosphate+dehydrogenase+in+Mycobacterium+and+Nocardia+species,+but+absence+from+Streptomyces+and+Corynebacterium+species+and+methanogenic+Archaea.">Presence of F420-dependent glucose-6-phosphate dehydrogenase in Mycobacterium and Nocardia species, but absence from Streptomyces and Corynebacterium species and methanogenic Archaea.</a> FEMS Microbiology Letters. 146 (1), 129-134 (1997).</li><li>Purwantini, E., Daniels, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Purification+of+a+novel+coenzyme+F420-dependent+glucose-6-phosphate+dehydrogenase+from+Mycobacterium+smegmatis.">Purification of a novel coenzyme F420-dependent glucose-6-phosphate dehydrogenase from Mycobacterium smegmatis.</a> Journal of Bacteriology. 178 (10), 2861-2866 (1996).</li><li>McCormick, J. 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A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Discovery,+production,+and+biological+assay+of+an+unusual+flavenoid+cofactor+involved+in+lincomycin+biosynthesis.">Discovery, production, and biological assay of an unusual flavenoid cofactor involved in lincomycin biosynthesis.</a> The Journal of Antibiotics. 42 (3), 472-474 (1989).</li><li>Bown, L., Altowairish, M. S., Fyans, J. K., Bignell, D. R. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Production+of+the+Streptomyces+scabies+coronafacoyl+phytotoxins+involves+a+novel+biosynthetic+pathway+with+an+F420+-dependent+oxidoreductase+and+a+short-chain+dehydrogenase/reductase.">Production of the Streptomyces scabies coronafacoyl phytotoxins involves a novel biosynthetic pathway with an F420 -dependent oxidoreductase and a short-chain dehydrogenase/reductase.</a> Molecular Microbiology. 101 (1), 122-135 (2016).</li><li>Gurumurthy, M., 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+novel+F(420)+-dependent+anti-oxidant+mechanism+protects+Mycobacterium+tuberculosis+against+oxidative+stress+and+bactericidal+agents.">A novel F(420) -dependent anti-oxidant mechanism protects Mycobacterium tuberculosis against oxidative stress and bactericidal agents.</a> Molecular microbiology. 87 (4), 744-755 (2013).</li><li>Greening, 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=Mycobacterial+F420H2-dependent+reductases+promiscuously+reduce+diverse+compounds+through+a+common+mechanism.">Mycobacterial F420H2-dependent reductases promiscuously reduce diverse compounds through a common mechanism.</a> Frontiers in Microbiology. 8, 1000 (2017).</li><li>Mathew, S., Trajkovic, M., Kumar, H., Nguyen, Q. -. 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The authors have nothing to disclose.

For the evaluation of cofactor F420 from methanogenic pure cultures, a microscopic evaluation can be performed to visualize the growth and activity (fluorescence microscopy) of the involved microorganisms (Figure 1). For samples deriving from natural environments, the use of microscopy to detect or quantify F420 is limited due to interferences with other fluorescent microorganisms, organic and inorganic particles. In this context, extraction of F420 and subse...

F420 is a widespread but often neglected cofactor, which functions as an obligate two-electron hydride carrier in primary and secondary metabolic processes of both Archaea and Bacteria1,2. F420 is a 5-deazaflavin and structurally similar to flavins, whereby its chemical and biological properties are more comparable with those of NAD+ or NADP+. Due to the substitution of nitrogen with carbon at position 5 of the isoalloxazine ring, it is a strong reductant, thus exhibiting a low standard redox potential of -340 mV1,3. F420 comprises a 5-deazaflavin ring and a 2-phospho-L-lactate linker (F420-0). An oligoglutamate tail containing n+1 glutamate monomers can be attached to the molecule (F420-n+1)4.
For a long time, the cofactor F420 has been solely associated with Archaea and Actinobacteria. This has largely been overturned. Recent analyses revealed that F420 is distributed among diverse anaerobic and aerobic organisms of the phyla Proteobacteria, Chloroflexi, and potentially Firmicutes inhabiting a myriad of habitats like soils, lakes, and the human gut1,5. In 2019, Braga et al.6, showed that the proteobacterium Paraburkholderia rhizoxinica produces a unique F420 derivative, containing a 3-phosphoglycerate instead of a 2-phospholactate tail, which might be widespread in various habitats. Within the domain Archaea, F420 has been found in several lineages, including methanogenic7, methanotrophic8,9, and sulfate-reducing orders10, and is supposed to be produced in Thaumarchaeota11.&#160;F420 is best known as an essential redox coenzyme in hydrogenotrophic and methylotrophic methanogenesis. The reduced form of F420 (F420H2) functions as an electron donor for the reduction of methylenetetrahydromethanopterin (methylene-H4MPT, Mer) and methenyl-H4MPT12,13. It can also be used as an electron carrier in H2-independent electron transport pathways of methanogens containing cytochromes12,14. Moreover, the oxidized form of F420 has a characteristic blue-green fluorescence upon excitation at 420 nm, which facilitates the detection of methanogens microscopically (Figure 1). Due to its low redox potential, F420 facilitates (i) the exogenous reduction of a broad spectrum of otherwise recalcitrant or toxic organic compounds, (ii) synthesis of tetracycline and lincosamide antibiotics or phytotoxins in streptomycetes (phylum Actinobacteria), and (iii) resistance to oxidative or nitrosative stress or other unfavorable conditions in mycobacteria (phylum Actinobacteria)1,5,15,16,17,18,19,20,21,22. Consequently, F420-dependent oxidoreductases are promising biocatalysts for industrial and pharmaceutical purposes as well as for bioremediation of contaminated environments1,23. Despite these recent findings, the exact roles of the cofactor F420 are still marginally known in Actinobacteria or other bacterial phyla.
There are at least three pathways for F420 biosynthesis2,6,24. In the beginning, the biosynthesis pathway is split into a 5-deazaflavin biosynthesis and a 2-phospholactate metabolism branch. The reactive part of the F420 molecule is synthesized via FO-synthase using the substrates tyrosine and 5-amino-6-ribitylamino-2,4(1H, 3H)-pyrimidinedione. The result is the riboflavin level chromophore FO. Within the currently accepted lactate metabolism branch, L-lactate is phosphorylated to 2-phospho-L-lactate by an L-lactate kinase (CofB); 2-phospho-L-lactate, in turn, is guanylated to L-lactyl-2-diphospho-5&#39;-guanosine by 2-phospho-L-lactate guanylyltransferase (CofC). In the next step, L-lactyl-2-diphospho-5&#39;-guanosine is linked to FO by a 2-phospho-L-lactate transferase (CofD) to form F420-02. Finally, the enzyme F420-0:&#611;-glutamyl ligase (CofE) ligates glutamate monomers to F420-0, forming the final cofactor6 in varying numbers23,25. Different organisms show different patterns in the number of attached glutamate residues, with shorter tails found for methanogens than in mycobacteria2,25,26. Generally, methanogens show tail lengths from two to three, with up to five in the acetoclastic methanogen, Methanosarcina sp., while tail lengths found in Mycobacterium sp. ranged from five to seven glutamate residues2,25,26,27. However, recent findings showed that long-chain F420 binds to F420-dependent oxidoreductases with a higher affinity than short-chain F420; moreover, bound long-chain F420 increases the substrate affinity but decreases the turnover rate of respective enzymes23.
Detection of cofactor F420 is often based on its fluorescence. Thereby, its oligo glutamate derivates were separated using reversed-phase (RP)-HPLC27,28. Recently, Ney et al. used tetrabutylammonium hydroxide as an ion-pairing reagent for the negatively charged glutamate tail to enhance separation on RP-HLPC successfully5. Here, we present a method for the preparation of samples, subsequent lysis, extraction, purification, separation, and quantification of cofactor F420 not only from pure cultures but also from different environmental samples (i.e., soils and digester sludge).

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Autoclave</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Biocompatible HPLC system equipped with gradient modul, oven and fluorescence detector</td>
			<td>Shimadzu</td>
			<td></td>
			<td>HPLC system</td>
		</tr>
		<tr>
			<td>Centrifuge and rotor for 50 mL &#8220;Falcon&#8221; tubes (11.000 rcf) and appropriate tubes</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>HPLC Column: Gemini NX C18, 5 &#956;m, 150 x 3 mm</td>
			<td>Phenomenex</td>
			<td></td>
			<td>HPLC column</td>
		</tr>
		<tr>
			<td>PTFE filter (pore size 0.22 &#181;m) to remove particulate matter prior HPLC analysis</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Resin for SPE: Strata-X-AW 33 &#956;m as weak anion mixed-mode polymeric sorbent</td>
			<td>Phenomenex</td>
			<td></td>
			<td>weak anion mixed-mode polymeric sorbent</td>
		</tr>
		<tr>
			<td>Vacuum manifold for SPE and appropriate collection tubes</td>
			<td></td>
			<td></td>
			<td>SPE equipment</td>
		</tr>
		<tr>
			<td>Vortex mixer</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
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extraction of cofactor f420 for analysis of polyglutamate tail length from methanogenic pure cultures and environmental samples

The cofactor F420 plays a central role as a hydride carrier in the primary and secondary metabolism of many bacterial and archaeal taxa. The cofactor is best known for its role in methanogenesis, where it facilitates thermodynamically difficult reactions. As the polyglutamate tail varies in length between different organisms, length profile analyses might be a powerful tool for distinguishing and characterizing different groups and pathways in various habitats. Here, the protocol describes the extraction and optimization of cofactor F420 detection by applying solid-phase extraction combined with high-performance liquid chromatography analysis independent of cultural or molecular biological approaches. The method was applied to gain additional information on the expression of cofactor F420 from microbial communities in soils, anaerobic sludge, and pure cultures and was evaluated by spiking experiments. Thereby, the study succeeded in generating different F420 tail-length profiles for hydrogenotrophic and acetoclastic methanogens in controlled methanogenic pure cultures as well as from environmental samples such as anaerobic digester sludge and soils.

Pure cultures of Methanosarcina thermophila and Methanoculleus thermophilus, both thermophilic methanogenic Archaea, were grown in suitable media as described previously29,30. For Methanosarcina thermophila, methanol was used as an energy source, whereas Methanoculleus thermophilus was grown on H2/CO2. Growth was checked by microscopic evaluation, while activity was examined via measurement of met...

Watch this Scientific Journal Video about Extraction of Cofactor F420 for Analysis of Polyglutamate Tail Length from Methanogenic Pure Cultures and Environmental Samples at JoVE.com

Extraction of Cofactor F420 for Analysis of Polyglutamate Tail Length from Methanogenic Pure Cultures and Environmental Samples

A method for the extraction of cofactor F420 from pure cultures was optimized for the liquid chromatographic separation and analysis of F420 tail length in pure culture and environmental samples.

Extraction of Cofactor F420 for Analysis of Polyglutamate Tail Length from Methanogenic Pure Cultures and Environmental Samples

The cofactor F420 plays a central role as a hydride carrier in the primary and secondary metabolism of many bacterial and archaeal taxa. The cofactor is ...

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2.5K Views.  Universität Innsbruck. A method for the extraction of cofactor F420 from pure cultures was optimized for the liquid chromatographic separation and analysis of F420 tail length in pure culture and environmental samples.

Video: Extraction of Cofactor F420 for Analysis of Polyglutamate Tail Length from Methanogenic Pure Cultures and Environmental Samples

EPA Method 1615. Measurement of Enterovirus and Norovirus Occurrence in Water by Culture and RT-qPCR. I. Collection of Virus Samples

EPA Method 1615 was developed with a goal of providing a standard method for measuring enteroviruses and noroviruses in environmental and drinking waters. The standardized sampling component of the method concentrates viruses that may be present in water by passage of a minimum specified volume of water through an electropositive cartridge filter. The minimum specified volumes for surface and finished/ground water are 300 L and 1,500 L, respectively. A major method limitation is the tendency for the filters to clog before meeting the sample volume requirement. Studies using two different, but equivalent, cartridge filter options showed that filter clogging was a problem with 10% of the samples with one of the filter types compared to 6% with the other filter type. Clogging tends to increase with turbidity, but cannot be predicted based on turbidity measurements only. From a cost standpoint one of the filter options is preferable over the other, but the water quality and experience with the water system to be sampled should be taken into consideration in making filter selections.

EPA Method 1615 uses an electropositive filter to concentrate enteroviruses and noroviruses in environmental and drinking waters. This manuscript describes the procedure for collecting samples for Method 1615 analyses.

EPA Method 1615 was developed with a goal of providing a standard method for measuring enteroviruses and noroviruses in environmental and drinking waters. ...

Use of Chironomidae (Diptera) Surface-Floating Pupal Exuviae as a Rapid Bioassessment Protocol for Water Bodies

Rapid bioassessment protocols using benthic macroinvertebrate assemblages have been successfully used to assess human impacts on water quality. Unfortunately, traditional benthic larval sampling methods, such as the dip-net, can be time-consuming and expensive. An alternative protocol involves collection of Chironomidae surface-floating pupal exuviae (SFPE). Chironomidae is a species-rich family of flies (Diptera) whose immature stages typically occur in aquatic habitats. Adult chironomids emerge from the water, leaving their pupal skins, or exuviae, floating on the water&#8217;s surface. Exuviae often accumulate along banks or behind obstructions by action of the wind or water current, where they can be collected to assess chironomid diversity and richness. Chironomids can be used as important biological indicators, since some species are more tolerant to pollution than others. Therefore, the relative abundance and species composition of collected SFPE reflect changes in water quality. Here, methods associated with field collection, laboratory processing, slide mounting, and identification of chironomid SFPE are described in detail. Advantages of the SFPE method include minimal disturbance at a sampling area, efficient and economical sample collection and laboratory processing, ease of identification, applicability in nearly all aquatic environments, and a potentially more sensitive measure of ecosystem stress. Limitations include the inability to determine larval microhabitat use and inability to identify pupal exuviae to species if they have not been associated with adult males.

Use of Chironomidae Diptera Surface-Floating Pupal Exuviae as a Rapid Bioassessment Protocol for Water Bodies

Rapid bioassessment protocols using benthic macroinvertebrates are often used to monitor and assess water quality. An efficient protocol involves collections of Chironomidae surface-floating pupal exuviae (SFPE). Here, techniques for field collection, laboratory processing, slide mounting, and identification of Chironomidae SFPE are described.

Rapid bioassessment protocols using benthic macroinvertebrate assemblages have been successfully used to assess human impacts on water quality. ...

Automated Gel Size Selection to Improve the Quality of Next-generation Sequencing Libraries Prepared from Environmental Water Samples

Next-generation sequencing of environmental samples can be challenging because of the variable DNA quantity and quality in these samples. High quality DNA libraries are needed for optimal results from next-generation sequencing. Environmental samples such as water may have low quality and quantities of DNA as well as contaminants that co-precipitate with DNA. The mechanical and enzymatic processes involved in extraction and library preparation may further damage the DNA. Gel size selection enables purification and recovery of DNA fragments of a defined size for sequencing applications. Nevertheless, this task is one of the most time-consuming steps in the DNA library preparation workflow. The protocol described here enables complete automation of agarose gel loading, electrophoretic analysis, and recovery of targeted DNA fragments. 
In this study, we describe a high-throughput approach to prepare high quality DNA libraries from freshwater samples that can be applied also to other environmental samples. We used an indirect approach to concentrate bacterial cells from environmental freshwater samples; DNA was extracted using a commercially available DNA extraction kit, and DNA libraries were prepared using a commercial transposon-based protocol. DNA fragments of 500 to 800 bp were gel size selected using Ranger Technology, an automated electrophoresis workstation. Sequencing of the size-selected DNA libraries demonstrated significant improvements to read length and quality of the sequencing reads.

This manuscript describes an automated gel size selection approach for purifying DNA fragments for next-generation sequencing. The Ranger Technology provides complete automation of the entire process of agarose gel loading, electrophoretic analysis, and recovery of targeted DNA fragments allowing for high-throughput and high quality next-generation sequencing libraries.

Next-generation sequencing of environmental samples can be challenging because of the variable DNA quantity and quality in these samples. High quality DNA ...

Physical Isolation of Endospores from Environmental Samples by Targeted Lysis of Vegetative Cells

Endospore formation is a survival strategy found among some bacteria from the phylum Firmicutes. During endospore formation, these bacteria enter a morpho-physiological resting state that enhances survival under adverse environmental conditions. Even though endospore-forming Firmicutes are one of the most frequently enriched and isolated bacterial groups in culturing studies, they are often absent from diversity studies based on molecular methods. The resistance of the spore core is considered one of the factors limiting the recovery of DNA from endospores. We developed a method that takes advantage of the higher resistance of endospores to separate them from other cells in a complex microbial community using physical, enzymatic and chemical lysis methods. The endospore-only preparation thus obtained can be used for re-culturing or to perform downstream analysis such as tailored DNA extraction optimized for endospores and subsequent DNA sequencing. This method, applied to sediment samples, has allowed the enrichment of endospores and after sequencing, has revealed a large diversity of endospore-formers in freshwater lake sediments. We expect that the application of this method to other samples will yield a similar outcome.

A method to single out bacterial endospores from complex microbial communities was developed to perform tailored culture or molecular studies of this group of bacteria.

Endospore formation is a survival strategy found among some bacteria from the phylum Firmicutes. During endospore formation, these bacteria enter a ...

A Simple Method for Automated Solid Phase Extraction of Water Samples for Immunological Analysis of Small Pollutants

A new method for solid phase extraction (SPE) of environmental water samples is proposed. The developed prototype is cost-efficient and user friendly, and enables to perform rapid, automated and simple SPE. The pre-concentrated solution is compatible with analysis by immunoassay, with a low organic solvent content. A method is described for the extraction and pre-concentration of natural hormone 17&#946;-estradiol in 100 ml water samples. Reverse phase SPE is performed with octadecyl-silica sorbent and elution is done with 200 &#181;l of methanol 50% v/v. Eluent is diluted by adding di-water to lower the amount of methanol. After preparing manually the SPE column, the overall procedure is performed automatically within 1 hr. At the end of the process, estradiol concentration is measured by using a commercial enzyme-linked immune-sorbent assay (ELISA). 100-fold pre-concentration is achieved and the methanol content in only 10% v/v. Full recoveries of the molecule are achieved with 1 ng/L spiked de-ionized and synthetic sea water samples.

A protocol for the extraction and pre-concentration of estradiol from water samples by using an automated and miniaturized system is presented.

A new method for solid phase extraction (SPE) of environmental water samples is proposed. The developed prototype is cost-efficient and user friendly, and ...

Preparation and Testing of Impedance-based Fluidic Biochips with RTgill-W1 Cells for Rapid Evaluation of Drinking Water Samples for Toxicity

This manuscript describes how to prepare fluidic biochips with Rainbow trout gill epithelial (RTgill-W1) cells for use in a field portable water toxicity sensor. A monolayer of RTgill-W1 cells forms on the sensing electrodes enclosed within the biochips. The biochips are then used for testing in a field portable electric cell-substrate impedance sensing (ECIS) device designed for rapid toxicity testing of drinking water. The manuscript further describes how to run a toxicity test using the prepared biochips. A control water sample and the test water sample are mixed with pre-measured powdered media and injected into separate channels of the biochip. Impedance readings from the sensing electrodes in each of the biochip channels are measured and compared by an automated statistical software program. The screen on the ECIS instrument will indicate either "Contamination Detected" or "No Contamination Detected" within an hour of sample injection. Advantages are ease of use and rapid response to a broad spectrum of inorganic and organic chemicals at concentrations that are relevant to human health concerns, as well as the long-term stability of stored biochips in a ready state for testing. Limitations are the requirement for cold storage of the biochips and limited sensitivity to cholinesterase-inhibiting pesticides. Applications for this toxicity detector are for rapid field-portable testing of drinking water supplies by Army Preventative Medicine personnel or for use at municipal water treatment facilities.

This manuscript describes how to prepare fluidic biochips with Rainbow trout gill epithelial cells for use in a field portable electric cell-substrate impedance sensor. The protocol for running a rapid drinking water toxicity test with the sensor is also described.

This manuscript describes how to prepare fluidic biochips with Rainbow trout gill epithelial (RTgill-W1) cells for use in a field portable water toxicity ...

Extraction and Analysis of Microbial Phospholipid Fatty Acids in Soils

Phospholipid fatty acids (PLFAs) are key components of microbial cell membranes. The analysis of PLFAs extracted from soils can provide information about the overall structure of terrestrial microbial communities. PLFA profiling has been extensively used in a range of ecosystems as a biological index of overall soil quality, and as a quantitative indicator of soil response to land management and other environmental stressors.
The standard method presented here outlines four key steps: 1. lipid extraction from soil samples with a single-phase chloroform mixture, 2. fractionation using solid phase extraction columns to isolate phospholipids from other extracted lipids, 3. methanolysis of phospholipids to produce fatty acid methyl esters (FAMEs), and 4. FAME analysis by capillary gas chromatography using a flame ionization detector (GC-FID). Two standards are used, including 1,2-dinonadecanoyl-sn-glycero-3-phosphocholine (PC(19:0/19:0)) to assess the overall recovery of the extraction method, and methyl decanoate (MeC10:0) as an internal standard (ISTD) for the GC analysis.

Phospholipid fatty acids provide information about the structure of soil microbial communities. We present methods for extraction from soil samples with a single-phase chloroform mixture, fractionation of extracted lipids using solid phase extraction columns, and methanolysis to produce fatty acid methyl esters, which are analyzed by capillary gas chromatography.

Phospholipid fatty acids (PLFAs) are key components of microbial cell membranes. The analysis of PLFAs extracted from soils can provide information about ...

Use of a Filter Cartridge for Filtration of Water Samples and Extraction of Environmental DNA

Recent studies demonstrated the use of environmental DNA (eDNA) from fishes to be appropriate as a non-invasive monitoring tool. Most of these studies employed disk fiber filters to collect eDNA from water samples, although a number of microbial studies in aquatic environments have employed filter cartridges, because the cartridge has the advantage of accommodating large water volumes and of overall ease of use. Here we provide a protocol for filtration of water samples using the filter cartridge and extraction of eDNA from the filter without having to cut open the housing. The main portions of this protocol consists of 1) filtration of water samples (water volumes &#8804;4 L or &gt;4 L); (2) extraction of DNA on the filter using a roller shaker placed in a preheated incubator; and (3) purification of DNA using a commercial kit. With the use of this and previously-used protocols, we perform metabarcoding analysis of eDNA taken from a huge aquarium tank (7,500 m3) with known species composition, and show the number of detected species per library from the two protocols as the representative results. This protocol has been developed for metabarcoding eDNA from fishes, but is also applicable to eDNA from other organisms.

We describe a protocol for filtration of water samples with a filter cartridge and extraction of environmental DNA (eDNA) without having to cut open the housing to remove the filter. This protocol is developed for metabarcoding eDNA from fishes, but is also applicable to eDNA from other organisms.

Recent studies demonstrated the use of environmental DNA (eDNA) from fishes to be appropriate as a non-invasive monitoring tool. Most of these studies ...

A Lipid Extraction and Analysis Method for Characterizing Soil Microbes in Experiments with Many Samples

Microbial communities are important drivers and regulators of ecosystem processes. To understand how management of ecosystems may affect microbial communities, a relatively precise but effort-intensive technique to assay microbial community composition is phospholipid fatty acid (PLFA) analysis. PLFA was developed to analyze phospholipid biomarkers, which can be used as indicators of microbial biomass and the composition of broad functional groups of fungi and bacteria. It has commonly been used to compare soils under alternative plant communities, ecology, and management regimes. The PLFA method has been shown to be sensitive to detecting shifts in microbial community composition.
An alternative method, fatty acid methyl ester extraction and analysis (MIDI-FA) was developed for rapid extraction of total lipids, without separation of the phospholipid fraction, from pure cultures as a microbial identification technique. This method is rapid but is less suited for soil samples because it lacks an initial step separating soil particles and begins instead with a saponification reaction that likely produces artifacts from the background organic matter in the soil. 
This article describes a method that increases throughput while balancing effort and accuracy for extraction of lipids from the cell membranes of microorganisms for use in characterizing both total lipids and the relative abundance of indicator lipids to determine soil microbial community structure in studies with many samples. The method combines the accuracy achieved through PLFA profiling by extracting and concentrating soil lipids as a first step, and a reduction in effort by saponifying the organic material extracted and processing with the MIDI-FA method as a second step.

The article describes a method that increases throughput while balancing effort and accuracy for extraction of lipids from the cell membranes of microorganisms for use in characterizing both total lipids and the relative abundance of indicator lipids to determine soil microbial community structure in studies with many samples.

Microbial communities are important drivers and regulators of ecosystem processes. To understand how management of ecosystems may affect microbial ...

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 ...