Name: in situ hybridization techniques for paraffin-embedded adult coral samples
Uploaded: 2018-08-31T13:00:00
Description: Watch this Scientific Journal Video about In Situ Hybridization Techniques for Paraffin-Embedded Adult Coral Samples at JoVE.com

This work was funded by award no. OCE-1323652 through the National Science Foundation Ocean Science Postdoctoral Fellowship and award no.1012629 from the Burroughs Wellcome Fund Postdoctoral Enrichment Program.

1. Removal of Paraffin
Caution: Perform the following steps under a fume hood.
<ol>
	<li>Dewax the thin-sectioned paraffin-embedded slides with 100% xylene under the hood in glass Coplin jars for 10 min. Do not use plastic Coplin jars, as xylene melts plastic. Sterilize the Coplin jars in an autoclave before use.</li>
	<li>Prepare four sterile glass Coplin jars with the following: 100% ethanol, 80% ethanol, 70% ethanol and 60% ethanol. Dilute the ethanol with RNase-free water.
	<ol>
		<li>Tr...

<ol>
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J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sox+genes+in+the+coral+Acropora+millepora:+divergent+expression+patterns+reflect+differences+in+developmental+mechanisms+within+the+Anthozoa.">Sox genes in the coral Acropora millepora: divergent expression patterns reflect differences in developmental mechanisms within the Anthozoa.</a> BMC Evolutionary Biology. 8 (1), 311 (2008).</li><li>Anctil, M., Hayward, D. C., Miller, D. J., Ball, E. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sequence+and+expression+of+four+coral+G+protein-coupled+receptors+distinct+from+all+classifiable+members+of+the+rhodopsin+family.">Sequence and expression of four coral G protein-coupled receptors distinct from all classifiable members of the rhodopsin family.</a> Gene. 392 (1-2), 14-21 (2007).</li><li>Darby, I. A., Hewitson, T. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> In situ hybridization protocols. , (2006).</li><li>Valentino, K. L., Eberwine, J. H., Barchas, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> In situ hybridization. , (1987).</li><li>Tautz, D., Pfeifle, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+non-radioactive+in+situ+hybridization+method+for+the+localization+of+specific+RNAs+in+Drosophila+embryos+reveals+translational+control+of+the+segmentation+gene+hunchback.">A non-radioactive in situ hybridization method for the localization of specific RNAs in Drosophila embryos reveals translational control of the segmentation gene hunchback.</a> Chromosoma. 98 (2), 81-85 (1989).</li><li>Traylor-Knowles, N., Rose, N. H., Palumbi, S. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+cell+specificity+of+gene+expression+in+the+response+to+heat+stress+in+corals.">The cell specificity of gene expression in the response to heat stress in corals.</a> Journal of Experimental Biology. 220 (10), (2017).</li><li>Wolenski, F. S., Layden, M. J., Martindale, M. Q., Gilmore, T. D., Finnerty, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterizing+the+spatiotemporal+expression+of+RNAs+and+proteins+in+the+starlet+sea+anemone,+Nematostella+vectensis.">Characterizing the spatiotemporal expression of RNAs and proteins in the starlet sea anemone, Nematostella vectensis.</a> Nature Protocols. 8, 900 (2013).</li><li>Schnitzler, C. E., Simmons, D. K., Pang, K., Martindale, M. Q., Baxevanis, A. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expression+of+multiple+Sox+genes+through+embryonic+development+in+the+ctenophore+Mnemiopsis+leidyi+is+spatially+restricted+to+zones+of+cell+proliferation.">Expression of multiple Sox genes through embryonic development in the ctenophore Mnemiopsis leidyi is spatially restricted to zones of cell proliferation.</a> EvoDevo. 5 (1), 15 (2014).</li><li>Traylor-Knowles, N. G., Kane, E. G., Sombatsaphay, V., Finnerty, J. R., Reitzel, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sex-specific+and+developmental+expression+of+Dmrt+genes+in+the+starlet+sea+anemone,+Nematostella+vectensis.">Sex-specific and developmental expression of Dmrt genes in the starlet sea anemone, Nematostella vectensis.</a> EvoDevo. 6 (1), (2015).</li><li>Barry, S. N., Crow, K. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+role+of+HoxA11+and+HoxA13+in+the+evolution+of+novel+fin+morphologies+in+a+representative+batoid+(Leucoraja+erinacea).">The role of HoxA11 and HoxA13 in the evolution of novel fin morphologies in a representative batoid (Leucoraja erinacea).</a> EvoDevo. 8 (1), 24 (2017).</li><li>Sharma, P. P., Gupta, T., Schwager, E. E., Wheeler, W. C., Extavour, C. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Subdivision+of+arthropod+cap-n-collar+expression+domains+is+restricted+to+Mandibulata.">Subdivision of arthropod cap-n-collar expression domains is restricted to Mandibulata.</a> EvoDevo. 5 (1), 3 (2014).</li><li>Piatigorsky, J., Kozmik, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cubozoan+jellyfish:+an+Evo/Devo+model+for+eyes+and+other+sensory+systems.">Cubozoan jellyfish: an Evo/Devo model for eyes and other sensory systems.</a> The International Journal of Developmental Biology. 48 (8-9), 719-729 (2004).</li></ol>

The method described in this protocol has been modified from previous work in medical and evolutionary developmental research8,9,10,12,17. This protocol focuses on the nuances of an in situ hybridization with a DIG-labeled RNA anti-sense probe on adult corals, which have been preserved and embedded in paraffin. This method can be easily transferred to...

Corals are critical ecosystem builders and important for biodiversity in ocean and human health1,2,3. They are under threat due to climate change and other anthropogenic stressors, and many coral species are considered critically endangered. Thus, there is a significant need for cellular and molecular tools to diagnose corals under stress. Also, there is little understood about where genes are expressed within adult coral tissue, and therefore little understanding of the functions of these genes. To address this issue, we have adapted the in situ hybridization (ISH) protocol, commonly used in human medicine and evolutionary developmental biology, for use on paraffin-embedded tissue samples of adult corals. This technique is most powerful when used on adult corals that have undergone a stressful event such as exposure to heat stress. However, this technique can be used on a wide range of tissues and life stages in corals and is not limited to only heat-stressed corals4,6,7. Additionally, this technique can be used on tissues or cells of any metazoan as long as there is cDNA sequence information available.
The purpose of this method is to visualize RNA probes within adult coral tissue that has been preserved and embedded in paraffin and sectioned onto slides. This method is a powerful diagnostic tool that allows for the visualization of nucleic acids within adult coral tissue. Initially this method was developed for medical diagnostics, and it has since become a popular tool in fields such as developmental biology and evolutionary developmental biology8,9,10. ISH is also a critical method, particularly in non-model systems, when genomic and transcriptomic sequence data are available but spatial gene expression patterns are unknown. For diagnostic work in non-model systems, this technique is powerful because it can indicate which cells and tissues express a gene of interest and can lead to more targeted therapeutic approaches8,9,10,11,12. Lastly, this technique is qualitative and more powerful when paired with quantitative gene expression data11.
The approach outlined in this paper will be of interest to researchers who have already designed a digoxigenin (DIG)-labeled RNA probe (both the sense and antisense probes) and are now ready to perform in situ hybridization of the probes to a sample. To perform this method, two serial sections of a paraffin coral tissue will be needed for each probe being tested. One section will be used for the sense probe and the other for the antisense probe. The sense probe will be a control to indicate non-specific binding. If staining is observed in the sense probe, then the antisense probe is not specific to the RNA of interest. Probes can be designed for any gene expressed. In this protocol, several examples are used that were previously found to be expressed during heat stress in corals: FBJ murine osteosarcoma viral oncogene homolog B (Fos-B), Activator protein (AP1), and Tumor necrosis factor receptor 41 (TNFR 41)11. ISH using DIG-labeled RNA probes is preferred over using radioactive probes because their handling is much safer10. In addition, this technique is highly sensitive and can be performed on a wide range of tissues and embryos beyond heat-stressed adult corals13,14,15,16.

<table>
	<tbody>
		<tr>
			<td>Denhardt&#39;s solution</td>
			<td>Affymetrix</td>
			<td>70468 50 ML</td>
			<td></td>
		</tr>
		<tr>
			<td>Bioworld Alkaline phosphatase buffer</td>
			<td>Fisher</td>
			<td>50-198-724</td>
			<td></td>
		</tr>
		<tr>
			<td>Slide mailers</td>
			<td>Fisher</td>
			<td>12-587-17B</td>
			<td></td>
		</tr>
		<tr>
			<td>Bioworld Alkaline phosphatase buffer</td>
			<td>Fisher</td>
			<td>50-198-724</td>
			<td></td>
		</tr>
		<tr>
			<td>50 mL Falcon tubes</td>
			<td>Fisher</td>
			<td>14-959-49A</td>
			<td></td>
		</tr>
		<tr>
			<td>UltraPure Salmon Sperm DNA solution</td>
			<td>Invitrogen</td>
			<td>15632-011</td>
			<td></td>
		</tr>
		<tr>
			<td>PBS - Phosphate-Buffered Saline (10X) pH 7.4</td>
			<td>Invitrogen</td>
			<td>AM9625</td>
			<td></td>
		</tr>
		<tr>
			<td>UltraPure DNase/RNase-Free Distilled Water, 10 x 500 mL</td>
			<td>Invitrogen</td>
			<td>10977-023</td>
			<td></td>
		</tr>
		<tr>
			<td>UltraPure DNase/RNase-Free Distilled Water, 10 x 500 mL</td>
			<td>Invitrogen</td>
			<td>10977-023</td>
			<td></td>
		</tr>
		<tr>
			<td>UltraPure Salmon Sperm DNA solution</td>
			<td>Invitrogen</td>
			<td>15632-011</td>
			<td></td>
		</tr>
		<tr>
			<td>Slide white apex superior adhesive</td>
			<td>Leica Biosystems</td>
			<td>3800080</td>
			<td></td>
		</tr>
		<tr>
			<td>PBS solution, pH 7.4</td>
			<td>Life Technologies</td>
			<td>10010072</td>
			<td></td>
		</tr>
		<tr>
			<td>Proteinase K, Molecular Grade, 2 mL</td>
			<td>New England Biolabs</td>
			<td>P8107S</td>
			<td></td>
		</tr>
		<tr>
			<td>Super Pap Pen Liquid Blocker</td>
			<td>Promega</td>
			<td>22309</td>
			<td></td>
		</tr>
		<tr>
			<td>DIG Anti-Digoxigenin-AP Fab fragments</td>
			<td>Roche</td>
			<td>11093274910</td>
			<td></td>
		</tr>
		<tr>
			<td>BM Purple, 100 mL</td>
			<td>Roche</td>
			<td>11442074001</td>
			<td></td>
		</tr>
		<tr>
			<td>DIG Wash and Block Buffer Set</td>
			<td>Roche</td>
			<td>11585762001</td>
			<td></td>
		</tr>
		<tr>
			<td>NBT/BCIP</td>
			<td>Roche</td>
			<td>11681451001</td>
			<td></td>
		</tr>
		<tr>
			<td>Formaldehyde solution, 500 mL size</td>
			<td>Sigma-Aldrich</td>
			<td>252549-500ML</td>
			<td></td>
		</tr>
		<tr>
			<td>SSC Buffer 20X concentration</td>
			<td>Sigma-Aldrich</td>
			<td>S6639-1L</td>
			<td></td>
		</tr>
		<tr>
			<td>Acetic Anhydride</td>
			<td>Sigma-Aldrich</td>
			<td>320102-100ML</td>
			<td></td>
		</tr>
		<tr>
			<td>Formamide</td>
			<td>Sigma-Aldrich</td>
			<td>47670-250ML-F</td>
			<td></td>
		</tr>
		<tr>
			<td>Triethanolamine</td>
			<td>Sigma-Aldrich</td>
			<td>90279-100ML</td>
			<td></td>
		</tr>
		<tr>
			<td>Heparin sodium salt from porcine intestinal mucosa</td>
			<td>Sigma-Aldrich</td>
			<td>H3149-10KU</td>
			<td></td>
		</tr>
		<tr>
			<td>Xylenes, AR (ACS), For Histological Use</td>
			<td>VWR</td>
			<td>MK866806</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol</td>
			<td>VWR</td>
			<td>EM-EX0276-4S</td>
			<td></td>
		</tr>
		<tr>
			<td>TE buffer</td>
			<td>VWR</td>
			<td>PAV6232</td>
			<td></td>
		</tr>
		<tr>
			<td>hybridization oven</td>
			<td>VWR</td>
			<td>97005-252, 97005-254</td>
			<td></td>
		</tr>
		<tr>
			<td>Orbital shaker</td>
			<td>VWR</td>
			<td>89032-088</td>
			<td></td>
		</tr>
	</tbody>
</table>

in situ hybridization techniques for paraffin-embedded adult coral samples

Corals are important ocean invertebrates that are critical for overall ocean health as well as human health. However, due to human impacts such as rising ocean temperatures and ocean acidification, corals are increasingly under threat. To tackle these challenges, advances in cell and molecular biology have proven to be crucial for diagnosing the health of corals. Modifying some of the techniques commonly used in human medicine could greatly improve researchers&#39; ability to treat and save corals. To address this, a protocol for in situ hybridization used primarily in human medicine and evolutionary developmental biology has been adapted for use in adult corals under stress.
The purpose of this method is to visualize the spatial expression of an RNA probe in adult coral tissue that has been embedded in paraffin and sectioned onto glass slides. This method focuses on removal of the paraffin and rehydration of the sample, pretreatment of the sample to ensure permeability of the sample, pre-hybridization incubation, hybridization of the RNA probe, and visualization of the RNA probe. This is a powerful method when using non-model organisms to discover where specific genes are expressed, and the protocol can be easily adapted for other non-model organisms. However, the method is limited in that it is primarily qualitative, because expression intensity can vary depending on the amount of time used during the visualization step and the concentration of the probe. Furthermore, patience is required, as this protocol can take up to 5 days (and in many cases, longer) depending on the probe being used. Finally, non-specific background staining is common, but this limitation can be overcome.

After completing this protocol, identification of cells and tissues that are expressing the RNA probe of interest will be achieved. The representative results for this protocol are for AP-1, FosB, and TNFR41. These results, previously published by Traylor-Knowles et al.11, show spatial expression of RNA probes on adult corals that were exposed to heat stress. Two examples of different staining types are presented in Figure 1. ...

Watch this Scientific Journal Video about In Situ Hybridization Techniques for Paraffin-Embedded Adult Coral Samples at JoVE.com

In Situ Hybridization Techniques for Paraffin-Embedded Adult Coral Samples

The goal of this protocol is to perform in situ hybridization on adult coral samples that have been embedded in paraffin and sectioned onto glass slides. This is a qualitative method used to visualize the spatial expression of an RNA anti-sense probe in paraffin-embedded tissues.

In Situ Hybridization Techniques for Paraffin-Embedded Adult Coral Samples

Corals are important ocean invertebrates that are critical for overall ocean health as well as human health. However, due to human impacts such as rising ...

This method can help answer key questions in coral cell biology, such as what types of tissues and cells express specific types of genes. The main advantage of this technique is that you have visual information on RNA expression. Though this method can provide insight into spatial gene expression in adult corals, it can also be used in other life stages of corals, as well as in other invertebrate systems.Generally individuals new to this method will struggle because there's so many steps and solutions to keep track of. So they need to pay attention to where they are in the protocol, and keep good track of time when doing the washes. Kevin Rodriguez, a technician in my laboratory, will be demonstrating this procedure.To begin, dewax thin sectioned paraffin embedded slides with 100%xylene in glass Coplin jars for 10 minutes under the hood. Next, fill four sterile glass Coplin jars with 100%ethanol, 80%ethanol, 70%ethanol and 60%ethanol respectively. First, transfer the slides to the Coplin jar containing 100%ethanol, and allow them to soak for 10 minutes.Then transfer the slides to another Coplin jar containing 100%ethanol. Repeat this process with each of the Coplin jars in decreasing order of ethanol concentration. First transfer the slides to a sterile slide mailer with 18 mL of PBS.Then wash the slides for five minutes at room temperature. Next, pour off 1 volume of PBS, and add approximately 10 mL of proteinase K solution to the mailer. Then incubate the mailer at 37 degrees Celsius for 15 minutes.While the slides incubate, place prehyb buffer in a boiling water bath for 10 minutes. Then allow the buffer to cool in an ice bath for 5 minutes. To stop digestion by the proteinase K reaction, remove the proteinase K and add 18 mL of 0.2%glycine PBS solution to the mailer.Then allow the mailer to sit at room temperature for 5 minutes. After this, remove the glycine PBS solution and replace it with 18 mL of 2x saline sodium citrate, or SSC. Wash the slides in SSC for 10 minutes at room temperature with shaking at 100-150 RPM.While the slides incubate in the hybridization oven, dilute the probes in hybridization buffer. Then place the diluted probes on a heat block at 86-90 degrees Celsius for 12 minutes, and allow them to cool on ice for one minute. Next, remove the slide mailer from the hybridization oven, and remove each slide with sterile tweezers.Lay the slides on a paper towel, and carefully remove excess buffer around the tissue samples. Using a PAP pen, draw a circle around each tissue sample. Then use a pipette to apply 25 microliters of diluted probe solution, and cover each sample with a plastic coverslip.After this, add 4x SSC and 50%formamide solution in the bottom of a slide moisture chamber. Then place the slides in the moisture chamber. Wash the slides with 18 mL of alkaline phosphatase buffer without magnesium chloride for 1 minute.Then pour out the buffer and replace it with 18 mL of Boehringer Mannheim blocking buffer diluted with maleic acid buffer. Incubate the slide mailer overnight at room temperature with gentle shaking. Next, prepare 20 mL of diluted DIG anti-deoxigenin-AP Fab fragments.Add the anti-dig antibody to a new sterile slide mailer, and transfer the slides from the old mailer. Then incubate the slides at room temperature for three hours with gentle shaking. After the incubation period, pour the anti-dig antibody out, and wash the slides with 18 mL of AP buffer without magnesium chloride for five minutes with gentle shaking.Next, pour out the AP buffer without magnesium chloride and add 18 mL of AP buffer. Wash the slides for five minutes with gentle shaking. Then remove the old AP buffer, replace it with 18 mL of fresh AP buffer, and repeat the wash.In a dark room, pour off the AP buffer and add 18 mL of BM-Purple to the mailer. Then incubate the slides at room temperature, checking for purple color development every half hour. To stop color development, transfer the slides to a new sterile mailer with 18 mL of TE buffer.Allow the slides to sit in the dark at room temperature for five minutes. Next, pour off the TE buffer, add 18 mL of RNase-Free water to the mailer, and wash the slides for one minute. Then remove the slides from the water and dry them with tissue.Add glycerol mounting medium, and place a coverslip on each slide. Finally, store the slides at 4 degrees Celsius until pictures are ready to be taken. Using this protocol, heat stressed coral tissue expressing AP-1, FosB, and TNFR41 were identified.As indicated by the diffuse tissue staining, the expression of anti-sense AP-1 is found throughout the epidermis and oral gastrodermis. Cell specific staining was also observed in FosB and TNFR41 expression. FosB stained cnidocytes and was specific to both spirocytes, which produce spirocysts, and nematocytes, which produce the microbasic mastigophore organelle.Likewise, TNFR41 was also expressed in nematocytes and spirocytes. While attempting this procedure, it's important to remember to not rush anything, because the washes and the incubations take time.

in-situ-hybridization-techniques-for-paraffin-embedded-adult-coral

Research

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Despite being one of the most productive fisheries in the Northwest Atlantic, much remains unknown about the natural reproductive dynamics of American lobsters. Recent work in exploited crustacean populations (crabs and lobsters) suggests that there are circumstances where mature females are unable to achieve their full reproductive potential due to sperm limitation. To examine this possibility in different regions of the American lobster fishery, a reliable and noninvasive method was developed for sampling large numbers of female lobsters at sea. This method involves inserting a blunt-tipped needle into the female&#39;s seminal receptacle to determine the presence or absence of a sperm plug and to withdraw a sample that can be examined for the presence of sperm. A series of control studies were conducted at the dock and in the laboratory to test the reliability of this technique. These efforts entailed sampling 294 female lobsters to confirm that the presence of a sperm plug was a reliable indicator of sperm within the receptacle and thus, mating. This paper details the methodology and the results obtained from a subset of the total females sampled. Of the 230 female lobsters sampled from George&#39;s Bank and Cape Ann, MA (size range = 71-145 mm in carapace length), 90.3% were positive for sperm. Potential explanations for the absence of sperm in some females include: immaturity (lack of physiological maturity), breakdown of the sperm plug after being used to fertilize a clutch of eggs, and lack of mating activity. The surveys indicate that this technique for examining the mating success of female lobsters is a reliable proxy that can be used in the field to document reproductive activity in natural populations.

A Noninvasive Method For In situ Determination of Mating Success in Female American Lobsters Homarus americanus

Fishery-induced changes to exploited crustacean fisheries, such as the American lobster fishery, could potentially influence their reproductive dynamics, leading to a reduction in mating success. This study&#39;s goal was to develop a noninvasive method for ascertaining the mating success of female lobsters that may be physiologically or functionally mature.

Despite being one of the most productive fisheries in the Northwest Atlantic, much remains unknown about the natural reproductive dynamics of American ...

Understanding Dissolved Organic Matter Biogeochemistry Through In Situ Nutrient Manipulations in Stream Ecosystems

Dissolved organic matter (DOM) is a highly diverse mixture of molecules providing one of the largest sources of energy and nutrients to stream ecosystems. Yet the in situ study of DOM is difficult as the molecular complexity of the DOM pool cannot be easily reproduced for experimental purposes. Nutrient additions to streams however, have been shown to repeatedly alter the in situ and ambient DOM pool. Here we demonstrate an easily replicable field-based method for manipulating the ambient pool of DOM at the ecosystem scale. During nutrient pulse experiments changes in the concentration of both dissolved organic carbon and dissolved organic nitrogen can be examined across a wide-range of nutrient concentrations. This method allows researchers to examine the controls on the DOM pool and make inferences regarding the role and function that certain fractions of the DOM pool play within ecosystems. We advocate the use of this method as a technique to help develop a deeper understanding of DOM biogeochemistry and how it interacts with nutrients. With further development this method may help elucidate the dynamics of DOM in other ecosystems.

Understanding Dissolved Organic Matter Biogeochemistry Through In Situ Nutrient Manipulations in Stream Ecosystems

Dissolved organic matter provides an important source of energy and nutrients to stream ecosystems. Here we demonstrate a field-based method to manipulate the ambient pool of dissolved organic matter in situ through easily replicable nutrient pulses.

Dissolved organic matter (DOM) is a highly diverse mixture of molecules providing one of the largest sources of energy and nutrients to stream ecosystems. ...

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 ...

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 ...

Preparation of Authigenic Pyrite from Methane-bearing Sediments for In Situ Sulfur Isotope Analysis Using SIMS

Different sulfur isotope compositions of authigenic pyrite typically result from the sulfate-driven anaerobic oxidation of methane (SO4-AOM) and organiclastic sulfate reduction (OSR) in marine sediments. However, unravelling the complex pyritization sequence is a challenge because of the coexistence of different sequentially formed pyrite phases. This manuscript describes a sample preparation procedure that enables the use of secondary ion mass spectroscopy (SIMS) to obtain in situ &#948;34S values of various pyrite generations. This allows researchers to constrain how SO4-AOM affects pyritization in methane-bearing sediments. SIMS analysis revealed an extreme range in &#948;34S values, spanning from -41.6 to +114.8&#8240;, which is much wider than the range of &#948;34S values obtained by the traditional bulk sulfur isotope analysis of the same samples. Pyrite in the shallow sediment mainly consists of 34S-depleted framboids, suggesting early diagenetic formation by OSR. Deeper in the sediment, more pyrite occurs as overgrowths and euhedral crystals, which display much higher SIMS &#948;34S values than the framboids. Such 34S-enriched pyrite is related to enhanced SO4-AOM at the sulfate-methane transition zone, postdating OSR. High-resolution in situ SIMS sulfur isotope analyses allow for the reconstruction of the pyritization processes, which cannot be resolved by bulk sulfur isotope analysis.

Preparation of Authigenic Pyrite from Methane-bearing Sediments for In Situ Sulfur Isotope Analysis Using SIMS

Analyses of the sulfur isotopic composition (&#948;34S) of pyrite from methane-bearing sediments have typically focused on bulk samples. Here, we applied secondary ion mass spectroscopy to analyze the &#948;34S values of various pyrite generations to understand the diagenetic history of pyritization.

Different sulfur isotope compositions of authigenic pyrite typically result from the sulfate-driven anaerobic oxidation of methane (SO4-AOM) and ...

Techniques for Investigating the Anatomy of the Ant Visual System

This article outlines a suite of techniques in light microscopy (LM) and electron microscopy (EM) which can be used to study the internal and external eye anatomy of insects. These include traditional histological techniques optimized for work on ant eyes and adapted to work in concert with other techniques such as transmission electron microscopy (TEM) and scanning electron microscopy (SEM). These techniques, although vastly useful, can be difficult for the novice microscopist, so great emphasis has been placed in this article on troubleshooting and optimization for different specimens. We provide information on imaging techniques for the entire specimen (photo-microscopy and SEM) and discuss their advantages and disadvantages. We highlight the technique used in determining lens diameters for the entire eye and discuss new techniques for improvement. Lastly, we discuss techniques involved in preparing samples for LM and TEM, sectioning, staining, and imaging these samples. We discuss the hurdles that one might come across when preparing samples and how best to navigate around them.

This article outlines a suite of techniques in light and electron microscopy to study the internal and external eye anatomy of insects. These include several traditional techniques optimized for work on ant eyes, detailed troubleshooting, and suggestions for optimization for different specimens and regions of interest.

This article outlines a suite of techniques in light microscopy (LM) and electron microscopy (EM) which can be used to study the internal and external eye ...

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 ...

Bioindication Testing of Stream Environment Suitability for Young Freshwater Pearl Mussels Using In Situ Exposure Methods

Knowledge of habitat suitability for freshwater mussels is an important step in the conservation of this endangered species group. We describe a protocol for performing in situ juvenile exposure tests within oligotrophic river catchments over one-month and three-month periods. Two methods (in both modifications) are presented to evaluate the juvenile growth and survival rate. The methods and modifications differ in value for the locality bioindication and each has its benefits as well as limitations. The sandy cage method works with a large set of individuals, but only some of the individuals are measured and the results are evaluated in bulk. In the mesh cage method, the individuals are kept and measured separately, but a low individual number is evaluated. The open water exposure modification is relatively easy to apply; it shows the juvenile growth potential of sites and can also be effective for water toxicity testing. The within-bed exposure modification needs a high workload but is closer to the conditions of a natural juvenile environment and it is better for reporting the real suitability of localities. On the other hand, more replications are needed in this modification due to its high-hyporheic environment variability.

Bioindication Testing of Stream Environment Suitability for Young Freshwater Pearl Mussels Using In Situ Exposure Methods

In situ bioindications enable determination of the suitability of an environment for endangered mussel species. We describe two methods based on the juvenile exposure of freshwater pearl mussels in cages to oligotrophic river habitats. Both methods are implemented in variants for open water and hyporheic water environments.

Knowledge of habitat suitability for freshwater mussels is an important step in the conservation of this endangered species group. We describe a protocol ...

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

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

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

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

In Situ Chemotaxis Assay to Examine Microbial Behavior in Aquatic Ecosystems

Microbial behaviors, such as motility and chemotaxis (the ability of a cell to alter its movement in response to a chemical gradient), are widespread across the bacterial and archaeal domains. Chemotaxis can result in substantial resource acquisition advantages in heterogeneous environments. It also plays a crucial role in symbiotic interactions, disease, and global processes, such as biogeochemical cycling. However, current techniques restrict chemotaxis research to the laboratory and are not easily applicable in the field. Presented here is a step-by-step protocol for the deployment of the in situ chemotaxis assay (ISCA), a device that enables robust interrogation of microbial chemotaxis directly in the natural environment. The ISCA is a microfluidic device consisting of a 20 well array, in which chemicals of interest can be loaded. Once deployed in aqueous environments, chemicals diffuse out of the wells, creating concentration gradients that microbes sense and respond to by swimming into the wells via chemotaxis. The well contents can then be sampled and used to (1) quantify strength of the chemotactic responses to specific compounds through flow cytometry, (2) isolate and culture responsive microorganisms, and (3) characterize the identity and genomic potential of the responding populations through molecular techniques. The ISCA is a flexible platform that can be deployed in any system with an aqueous phase, including marine, freshwater, and soil environments.

Presented here is the protocol for an in situ chemotaxis assay, a recently developed microfluidic device that enables studies of microbial behavior directly in the environment.

Microbial behaviors, such as motility and chemotaxis (the ability of a cell to alter its movement in response to a chemical gradient), are widespread ...