D.S.A acknowledges funding from Conselho Nacional de Pesquisa e Desenvolvimento (CNPq/Brazil), grant number #301808/2018-0, #313117/2019-5, Funda&#231;&#227;o de Amparo &#224; Pesquisa do Estado do Rio Grande do Sul (FAPERGS/Brazil), grant number, 21/2551-0001963-8, Coordena&#231;&#227;o de Aperfei&#231;oamento de Pessoal de N&#237;vel Superior (CAPES, Finance Code 001 for N.S.J and A.C.S)

NOTE: Escherichia coli OP50 (E. coli OP50) bacteria and Bristol N2 wild type strains can be obtained from the CGC, University of Minnesota, USA or from donation from a C. elegans laboratory. For researchers&#39; safety, it is imperative to use Personal Protective Equipment. Although the concentrations of reagents like hypochlorite and sodium hydroxide are low, it is essential to wear the recommended PPE, as highlighted in the manuscript, to minimize any potential risks associated with these che...

Evaluating Metabolism and Aging Pattern in &lt;i&gt;Caenorhabditis elegans&lt;/i&gt;

<ol>
	<li>Thorp, H. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ChatGPT+is+fun,+but+not+an+author.">ChatGPT is fun, but not an author.</a> Science. 379 (6630), 313 (2023).</li><li>Lemons, M. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+inquiry-based+approach+to+study+the+synapse:+Student-driven+experiments+using+C.">An inquiry-based approach to study the synapse: Student-driven experiments using C.</a> elegans. J Undergrad Neurosci Educ. 15 (1), A44-A55 (2016).</li><li>Andersen, J., Krichevsky, A., Leheste, J. R., Moloney, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Caenorhabditis+elegans+as+an+undergraduate+educational+tool+for+teaching+RNAi.">Caenorhabditis elegans as an undergraduate educational tool for teaching RNAi.</a> Biochem Mol Biol Educ. 36 (6), 417-427 (2008).</li><li>Martins, R. R., McCracken, A. W., Simons, M. J. P., Henriques, C. M., Rera, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=How+to+catch+a+smurf?+-+Ageing+and+beyond...+In+vivo+assessment+of+intestinal+permeability+in+multiple+model+organisms.">How to catch a smurf? - Ageing and beyond... In vivo assessment of intestinal permeability in multiple model organisms.</a> Bio Protoc. 8 (3), e2722 (2018).</li><li>Ellingwood, S. S., Cheng, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biochemical+and+clinical+aspects+of+glycogen+storage+diseases.">Biochemical and clinical aspects of glycogen storage diseases.</a> J Endocrinol. 238 (3), R131-R141 (2018).</li><li>Cori, C. F., Cori, G. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glycogen+formation+in+the+liver+from+d-and+l-lactic+acid.">Glycogen formation in the liver from d-and l-lactic acid.</a> J Bio Chem. 81 (2), 389-403 (1929).</li><li>Wosilait, W. D., Sutherland, E. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+relationship+of+epinephrine+and+glucagon+to+liver+phosphorylase.+II.+Enzymatic+inactivation+of+liver+phosphorylase.">The relationship of epinephrine and glucagon to liver phosphorylase. II. Enzymatic inactivation of liver phosphorylase.</a> J Biol Chem. 218 (1), 469-481 (1956).</li><li>Zhang, H., Ma, J., Tang, K., Huang, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Beyond+energy+storage:+roles+of+glycogen+metabolism+in+health+and+disease.">Beyond energy storage: roles of glycogen metabolism in health and disease.</a> FEBS J. 288 (12), 3772-3783 (2021).</li><li>Liu, Q., 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=Characterization+of+glycogen+molecular+structure+in+the+worm+Caenorhabditis+elegans.">Characterization of glycogen molecular structure in the worm Caenorhabditis elegans.</a> Carbohydr Polym. 237, 116181 (2020).</li><li>Cherkas, A., 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=Label-free+molecular+mapping+and+assessment+of+glycogen+in+C.">Label-free molecular mapping and assessment of glycogen in C.</a> elegans.Analyst. 144 (7), 2367-2374 (2019).</li><li>Gusarov, I., 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=Glycogen+controls+Caenorhabditis+elegans+lifespan+and+resistance+to+oxidative+stress.">Glycogen controls Caenorhabditis elegans lifespan and resistance to oxidative stress.</a> Nat Commun. 8, 15868 (2017).</li><li>Seo, Y., Kingsley, S., Walker, G., Mondoux, M. A., Tissenbaum, H. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metabolic+shift+from+glycogen+to+trehalose+promotes+lifespan+and+healthspan+in+Caenorhabditis+elegans.">Metabolic shift from glycogen to trehalose promotes lifespan and healthspan in Caenorhabditis elegans.</a> Proc Natl Acad Sci U S A. 115 (12), E2791-E2800 (2018).</li><li>Frazier, H. N., Roth, M. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adaptive+sugar+provisioning+controls+survival+of+C.+elegans+embryos+in+adverse+environments.">Adaptive sugar provisioning controls survival of C. elegans embryos in adverse environments.</a> Curr Biol. 19 (10), 859-863 (2009).</li><li>da Silva, F. N., Zimath, P. L., do Amaral, T. A., Martins, J. R. N., Rafacho, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coadministration+of+olanzapine+causes+minor+impacts+on+the+diabetogenic+outcomes+induced+by+dexamethasone+treatment+in+rats.">Coadministration of olanzapine causes minor impacts on the diabetogenic outcomes induced by dexamethasone treatment in rats.</a> Life Sci. 322, 121660 (2023).</li><li>Gusarov, I., Nudler, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glycogen+at+the+crossroad+of+stress+resistance,+energy+maintenance,+and+pathophysiology+of+aging.">Glycogen at the crossroad of stress resistance, energy maintenance, and pathophysiology of aging.</a> Bioessays. 40 (9), e1800033 (2018).</li><li>Untersmayr, E., Brandt, A., Koidl, L., Bergheim, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+intestinal+barrier+dysfunction+as+driving+factor+of+inflammaging.">The intestinal barrier dysfunction as driving factor of inflammaging.</a> Nutrients. 14 (5), 949 (2022).</li><li>Lin, P. Y., Stern, A., Peng, H. H., Chen, J. H., Yang, H. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Redox+and+metabolic+regulation+of+intestinal+barrier+function+and+associated+disorders.">Redox and metabolic regulation of intestinal barrier function and associated disorders.</a> Int J Mol Sci. 23 (22), 14463 (2022).</li><li>Dambroise, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Two+phases+of+aging+separated+by+the+Smurf+transition+as+a+public+path+to+death.">Two phases of aging separated by the Smurf transition as a public path to death.</a> Sci Rep. 6, 23523 (2016).</li><li>Laranjeiro, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Swim+exercise+in+Caenorhabditis+elegans+extends+neuromuscular+and+gut+healthspan,+enhances+learning+ability,+and+protects+against+neurodegeneration.">Swim exercise in Caenorhabditis elegans extends neuromuscular and gut healthspan, enhances learning ability, and protects against neurodegeneration.</a> Proc Natl Acad Sci U S A. 116 (47), 23829-23839 (2019).</li><li>Stiernagle, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Maintenance+of+C.">Maintenance of C.</a> elegans.WormBook. , 1-11 (2006).</li><li>McGhee, 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=The+C.+elegans+intestine.">The C. elegans intestine.</a> WormBook: The Online Review of C. elegans Biology. , (2007).</li><li>McGee, M. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Loss+of+intestinal+nuclei+and+intestinal+integrity+in+aging+C.">Loss of intestinal nuclei and intestinal integrity in aging C.</a> elegans. Aging Cell. 10 (4), 699-710 (2011).</li><li>Gelino, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intestinal+autophagy+improves+healthspan+and+longevity+in+C.+elegans+during+dietary+restriction.">Intestinal autophagy improves healthspan and longevity in C. elegans during dietary restriction.</a> PLoS genetics. 12 (7), e1006135 (2016).</li><li>Rera, M., Clark, R. I., Walker, D. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intestinal+barrier+dysfunction+links+metabolic+and+inflammatory+markers+of+aging+to+death+in+Drosophila.">Intestinal barrier dysfunction links metabolic and inflammatory markers of aging to death in Drosophila.</a> Proc Natl Acad Sci U S A. 109 (52), 21528-21533 (2012).</li><li>Zhang, G., Gu, Y., Dai, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Protective+effect+of+bilberry+anthocyanin+extracts+on+dextran+sulfate+sodium-induced+intestinal+damage+in+Drosophila+melanogaster.">Protective effect of bilberry anthocyanin extracts on dextran sulfate sodium-induced intestinal damage in Drosophila melanogaster.</a> Nutrients. 14 (14), 2875 (2022).</li><li>Gelino, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intestinal+autophagy+improves+healthspan+and+longevity+in+C.+elegans+during+dietary+restriction.">Intestinal autophagy improves healthspan and longevity in C. elegans during dietary restriction.</a> PLoS Genet. 12 (7), e1006135 (2016).</li><li>Qu, M., Xu, K., Li, Y., Wong, G., Wang, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Using+acs-22+mutant+Caenorhabditis+elegans+to+detect+the+toxicity+of+nanopolystyrene+particles.">Using acs-22 mutant Caenorhabditis elegans to detect the toxicity of nanopolystyrene particles.</a> Sci Total Environ. 643, 119-126 (2018).</li></ol>

In summary, this protocol provides a qualitative evaluation of glycogen content in individual C. elegans worms using Lugol staining: a straightforward, robust, and swift assay. Lugol staining is a label-free and non-invasive approach that facilitates the acquisition of molecular data at subcellular resolutions, allowing for the monitoring of glycogen content fluctuations within single worms10. Furthermore, the assay offers the advantage of cost-effectiveness due to its minimal equipment r...

Biological sciences teaching in high school is a continuous challenge. Notably, the access and use of technology have brought important advances in the teaching-learning process, however, tools such as artificial intelligence chatbots make rationalizing and seeking evidence more difficult due to easy (and sometimes incorrect) responses obtained1. Because of that, the use of a scientific method with practical experimentation in an inquiry-based approach in the classroom is an important strategy to develop or stimulate critical thinking, creativity, and technical skills in the students2.
In this context, the free living nematode Caenorhabditis elegans has been successfully used in experimentation for teaching purposes3 because of its particular advantages: It is not a parasite and the Escherichia coli used for feeding is biosafety level-1, therefore reducing near to zero the biological hazard; it has an elegant and quantifiable locomotion movement, which is interesting for students to observe; and it is transparent, which allows organ observation, but also staining with pigments that can indicate the presence of biomolecules or the occurrence of physiological alterations4. Therefore, it is possible to hypothesize and test in the classroom simple postulations related to biochemistry and physiological changes such as aging.
Glycogen is a storage carbohydrate, formed by a long and branched chain of glucose molecules formed by glucosyl residues with (1&#8594;4)-&#945; glycosidic linear linkages and (1&#8594;6)-&#945; glycosidic bonds at branch points and is particularly important for muscle contraction, cell differentiation and glycemia maintenance5. Glycogen is synthesized after feeding due to insulin activation of the enzyme glycogen-synthase. During exercise or fasting, epinephrine or glucagon, respectively, activate glycogen phosphorylase and, therefore, break down the polysaccharide to provide glucose-6-phosphate to the muscle cells or release free glucose to circumvent hypoglycemia6,7. Alterations in glycogen levels impacts cell differentiation, signaling, redox regulation, and stemness under various physiological and pathophysiological conditions, including cancer8. In C. elegans, glycogen is mainly found in esophageal muscle, hypodermis, intestine, neurons and mainly in body wall muscles9. The glycogen content can be measured by using Lugol&#39;s Iodine solution, since iodine binds into the helical coils forming an iodine-glycogen complex, giving a visible sharp blue-black or brown-black color, which has been successfully used to demonstrate glycogen content in C. elegans10. It has been demonstrated that glycogen accumulation caused by high glucose feeding can reduce worm&#39;s lifespan, therefore accelerating the aging process11,12. In addition, metabolic disturbances, other hormones, and exposure to xenobiotics can alter glycogen metabolism as well13,14. Therefore, experimentation on glycogen content in C. elegans is quite interesting, since diverse factors may disturb its metabolism and can stimulate an in-class discussion on basic biochemistry associated with transversal themes such as exercise, diets, diseases, and aging.
Aging is a time-dependent functional decline caused by cellular damage. This damage can be associated with oxidative stress, telomere attrition, loss of proteostasis, inflammation and even by accumulation of insoluble polyglucosan bodies15, just to name a few. One of the hallmarks of aging is the reduction of intestinal integrity, associated with several chronic conditions that occur during the life of an organism16. Maintenance of intestinal homeostasis depends on the integrity of the intestinal epithelium, which is supported by junctional proteins forming a physical barrier and connecting adjacent epithelial cells. When there is damage to this epithelium, leakage of luminal content into the interstitium occurs17. Based on this mechanism, the smurf test has been used to verify intestinal integrity in several animal models, since this blue dye Erioglaucine disodium salt does not cross the intestinal membrane, remaining in the lumen18. When worms are infected with a pathogen, contaminated with some toxicants or age, altering the interstitial integrity, the dye crosses the barrier and spreads all over the worm, which becomes all blue. This assay allows discussion on the physiology of aging and experimenting on factors that can accelerate or delay this process by exposing worms to different conditions. The protocols here will describe in detail these two, dye-based methods that can be easily done in class to instigate and stimulate students to formulate and test hypotheses related to biochemistry and physiology.
The first part of protocol shows its applicability to analyze qualitatively and quantitatively the glycogen content in C. elegans model10. The purpose of second part of the protocol is to assess the integrity of the C. elegans intestine. This technique allows for the monitoring of C. elegans aging by evaluating the integrity of the intestinal membranes. Furthermore, it allows evaluating whether a substance accelerates or delays aging and whether any substances have toxic potential on the intestinal barrier19.
The C. elegans strain used for the present study was Bristol N2 wild type. However, the procedure can be replicated using strains that exhibit comparable growth rates, or the method must be adjusted based on need of equipment replacement, considering they have the same or similar function, or depending on the strain used, as certain strains have specific maintenance and/or sensitivity requirements; this information can be obtained from the Caenorhabditis Genetics Center (CGC) or WormBase website. These changes should not impact the reproducibility of the method.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>1.5 mL microtubes&#160;</td>
			<td>Local suppliers</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>37-degree incubator</td>
			<td>KS 4000i&#160;</td>
			<td>97014-816</td>
			<td></td>
		</tr>
		<tr>
			<td>50 mL conical tube</td>
			<td>Local suppliers</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>6 cm Petri plates&#160;</td>
			<td>Local suppliers</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>Agar bacteriological</td>
			<td>Din&#226;mica Qu&#237;mica Contempor&#226;nea Ltda.</td>
			<td>9002-18-0</td>
			<td></td>
		</tr>
		<tr>
			<td>C. elegans Bristol N2 (wild type)</td>
			<td>Caenorhabditis elegans Genetic Center (CGC, Minnesota, USA)</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>CaCL2</td>
			<td>Din&#226;mica Qu&#237;mica Contempor&#226;nea Ltda.</td>
			<td>10035-04-8</td>
			<td></td>
		</tr>
		<tr>
			<td>Cholesterol</td>
			<td>Sigma-Aldrich Brasil Ltda</td>
			<td>57-88-5</td>
			<td></td>
		</tr>
		<tr>
			<td>D-(+)-Glucose anhydrous&#160;</td>
			<td>Neon</td>
			<td>50-99-7</td>
			<td></td>
		</tr>
		<tr>
			<td>Distilled H2O</td>
			<td>Local suppliers</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>Erioglaucine disodium salt</td>
			<td>Sigma-Aldrich Brasil Ltda</td>
			<td>3844-45-9</td>
			<td></td>
		</tr>
		<tr>
			<td>Escherichia coli OP50</td>
			<td>Caenorhabditis elegans Genetic Center (CGC, Minnesota, USA)</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>Flow hood</td>
			<td>Mylabor</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Incubator</td>
			<td>Panasonic Healthcare company of North America, MIR-254-PA.</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>KH2PO4</td>
			<td>Din&#226;mica Qu&#237;mica Contempor&#226;nea Ltda.</td>
			<td>7778-77-0</td>
			<td></td>
		</tr>
		<tr>
			<td>Levamisole hydrochloride</td>
			<td>RIPERCOL L 150F</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>Lugol solution</td>
			<td>Sigma-Aldrich Brasil Ltda</td>
			<td>L6146</td>
			<td></td>
		</tr>
		<tr>
			<td>MgSO4</td>
			<td>Synth</td>
			<td>S1063-01-AH</td>
			<td></td>
		</tr>
		<tr>
			<td>Microcentrifuge</td>
			<td>Centrifuge 5425R Eppendorf SE, Germany</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Na2HPO4</td>
			<td>Din&#226;mica Qu&#237;mica Contempor&#226;nea Ltda.</td>
			<td>7558-79-4</td>
			<td></td>
		</tr>
		<tr>
			<td>NaCl</td>
			<td>Din&#226;mica Qu&#237;mica Contempor&#226;nea Ltda.</td>
			<td>7647-14-5</td>
			<td></td>
		</tr>
		<tr>
			<td>Nystatin</td>
			<td>Sigma-Aldrich Brasil Ltda</td>
			<td>N6261</td>
			<td></td>
		</tr>
		<tr>
			<td>Peptone bacteriological</td>
			<td>&#234;xodo cient&#237;fica</td>
			<td>91079-38-8</td>
			<td></td>
		</tr>
		<tr>
			<td>Stereomicroscope</td>
			<td>Leica S8 Apo Stereomicroscope (S&#227;o Paulo, Brazil)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Streptomycin Sulfate</td>
			<td>Estreptomax</td>
			<td>-</td>
			<td></td>
		</tr>
	</tbody>
</table>

using low-cost dyes to visualize glycogen accumulation and gut integrity in caenorhabditis elegans

Caenorhabditis elegans (C. elegans) is a transparent, non-parasitic nematode with a simple biology, which makes it a great tool for biological sciences teaching through the staining of the cells or their molecular content. Lugol dye (iodine-potassium iodide solution) has been widely used in biochemistry to stain glycogen stores. In this context, it is possible to observe differences between fed and starved animals, besides the effects of different conditions, such as different diets and oxygen levels. Erioglaucine is a blue dye that indicates the loss of the intestinal barrier. When the intestinal barrier is intact, the blue dye stains inside the lumen; however, when this integrity is disrupted, the dye leaks into the body cavity. Using a stereomicroscope or a microscope, teachers can demonstrate physiological and biochemical alterations, or they can instigate students to ask a scientific question and hypothesize and test their hypothesis using these assays. The present protocol describes two staining techniques in C. elegans that can be easily carried out by students.

Author Spotlight: Exploring Metabolic and Aging Processes in &lt;i&gt;C. elegans&lt;/i&gt;  Using Low-Cost, High-Impact Assays

Using Low-Cost Dyes to Visualize Glycogen Accumulation and Gut Integrity in Caenorhabditis elegans

The nematodes in Caenorhabditis elegans is easy to cultivate, to maintain, to manipulate, and to be used in experiments for biological science teaching, and also for students to carry out their projects. This protocol brings two easy and low cost assays that are based on the transparency of the nematode, and also on on the use of colored dyes. The first protocol allows the investigation of metabolic chains following different diets, and the second protocol allows the observation of the aging process in a short period of time.These both assays are interesting for educational purposes, under limited resources. The first assay takes an advantage of the worm's transparency, and the fact that it produce and it stores glycogen. Using the Lugol iodine solution, we can dye the worms, and verify whether different diets or other factors can modify its levels.Aging is a natural process, but some factors such as ultraviolet, food and chemicals exposure can accelerate this process. The intestinal barrier is modified with the agent, and the epithelial loses integrity, causing leakage of the substance the worms intake, such as the walls thin. We call this assay Smurf test, because the worms get totally blue when there is a reduction of intestinal integrity.

The glycogen content assay provides a robust and rapid method for screening various testing conditions, such as comparative studies of different strains that may influence glycogen synthesis or degradation. In this study, L4 worms were subjected to three distinct test conditions: fasting, feeding, and glucose-enriched groups. The assay was performed three times, with each condition replicated twice in each assay; a representative image is displayed in Figure 3. Following each assay, worms st...

Read this Scientific Article Protocol about Using Low-cost Dyes to Visualize Glycogen Accumulation and Gut Integrity in Caenorhabditis elegans at JoVE.com

Teaching biological sciences can be made more stimulating for students through the use of experimentation. This manuscript presents two different yet complementary protocols that can be utilized in the classroom to encourage students to formulate and test hypotheses related to high-calorie diets, starvation, and aging.

Caenorhabditis elegans (C. elegans) is a transparent, non-parasitic nematode with a simple biology, which makes it a great tool for biological sciences ...

using-low-cost-dyes-to-visualize-glycogen-accumulation-gut-integrity

Research

JoVE Journal

Biology

406 Views.  Federal University of Pampa. The nematodes in Caenorhabditis elegans is easy to cultivate, to maintain, to manipulate, and to be used in experiments for biological science teaching, and also for students to carry out their projects. This protocol brings two easy and low cost assays that are based on the transparency of the nematode, and also on on the use of colored dyes. The first protocol allows the investigation of metabolic chains following different diets, and the second protocol allows the observation of the aging ...