This work was supported by Programa de Apoyo a Proyectos de Investigaci&#243;n e Innovaci&#243;n Tecnol&#243;gica (PAPIIT), with a grant number IT200819. The authors acknowledge to Tom Musselman, Rock Paper Editing, LLC, for checking the English grammar of this manuscript; and the technical assistance of Samanta Jim&#233;nez (CICESE, Ensenada), and Juan Manuel Barbosa Castillo (Instituto de Fisiolog&#237;a Celular, UNAM).&#160;We also thank to Dr Augusto C&#233;sar Lizarazo Chaparro (CEPIPSA) for obtaining sheep blood.&#160;We especially thank Dr Jos&#233; Saniger Blesa, ICAT-UNAM,&#160;&#160;for the facilities in his laboratory for the video recording.&#160;

The sea anemones were collected according to guidelines of the National Commission for Aquaculture, Fisheries, and Food of the Federal Government of Mexico (permit number PPF / DGOPTA 07332.250810.4060). Bioethics Committee of the Institute of Biotechnology, National Autonomous University of Mexico approved all the experiments with sea anemones. The sheep blood sample was purchased at the Center for Practical Teaching and Research in Animal Production and Health (CEPIPSA, National Autonomous University of Mexico).
<p...

<ol>
	<li>Fraz&#227;o, B., Vasconcelos, V., Antunes, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sea+anemone+(Cnidaria,+Anthozoa,+Actiniaria)+toxins:+an+overview.">Sea anemone (Cnidaria, Anthozoa, Actiniaria) toxins: an overview.</a> Marine Drugs. 10 (8), 1812-1851 (2012).</li><li>Jayathilake, J. M. N. J., Gunathilake, K. V. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cnidarian+toxins:+recent+evidences+for+potential+therapeutic+uses.">Cnidarian toxins: recent evidences for potential therapeutic uses.</a> The European Zoological Journal. 87 (1), 708-713 (2020).</li><li>Ram&#237;rez-Carreto, S., Miranda-Zaragoza, B., Rodr&#237;guez-Almaz&#225;n, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Actinoporins:+From+the+structure+and+function+to+the+generation+of+biotechnological+and+therapeutic+tools.">Actinoporins: From the structure and function to the generation of biotechnological and therapeutic tools.</a> Biomolecules. 10 (4), 539 (2020).</li><li>Fautin, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structural+diversity,+systematics,+and+evolution+of+cnidae.+Toxicon.">Structural diversity, systematics, and evolution of cnidae. Toxicon.</a> Official Journal of the International Society on Toxinology. 54 (8), 1054-1064 (2009).</li><li>Moran, Y., 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=Analysis+of+soluble+protein+contents+from+the+nematocysts+of+a+model+sea+anemone+sheds+light+on+venom+evolution.">Analysis of soluble protein contents from the nematocysts of a model sea anemone sheds light on venom evolution.</a> Marine Biotechnology. 15 (3), 329-339 (2013).</li><li>Moran, Y., 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=Neurotoxin+localization+to+ectodermal+gland+cells+uncovers+an+alternative+mechanism+of+venom+delivery+in+sea+anemones.">Neurotoxin localization to ectodermal gland cells uncovers an alternative mechanism of venom delivery in sea anemones.</a> Proceedings of the Royal Society B: Biological Sciences. 279 (1732), 1351-1358 (2012).</li><li>Grabski, A. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Advances+in+preparation+of+biological+extracts+for+protein+purification.">Advances in preparation of biological extracts for protein purification.</a> Methods in Enzymology. 463, 285-303 (2009).</li><li>Bulati, 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=Partially+purified+extracts+of+sea+anemone+Anemonia+viridis+affect+the+growth+and+viability+of+selected+tumour+cell+lines.">Partially purified extracts of sea anemone Anemonia viridis affect the growth and viability of selected tumour cell lines.</a> BioMed Research International. 2016, 3849897 (2016).</li><li>Orts, D. J. B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biochemical+and+electrophysiological+characterization+of+two+sea+anemone+type+1+potassium+toxins+from+a+geographically+distant+population+of+Bunodosoma+caissarum.">Biochemical and electrophysiological characterization of two sea anemone type 1 potassium toxins from a geographically distant population of Bunodosoma caissarum.</a> Marine Drugs. 11 (3), 655-679 (2013).</li><li>Hader, D., Erzinger, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Bioassays: Advanced Methods and Applications. , (2017).</li><li>Anderluh, G., Macek, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cytolytic+peptide+and+protein+toxins+from+sea+anemones+(Anthozoa:+Actiniaria).">Cytolytic peptide and protein toxins from sea anemones (Anthozoa: Actiniaria).</a> Toxicon: Official Journal of the International Society on Toxinology. 40 (2), 111-124 (2002).</li><li>Nevalainen, T. J., 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=Phospholipase+A2+in+cnidaria.">Phospholipase A2 in cnidaria.</a> Comparative Biochemistry and Physiology. Part B, Biochemistry &amp; Molecular Biology. 139 (4), 731-735 (2004).</li><li>Razpotnik, 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=A+new+phospholipase+A2+isolated+from+the+sea+anemone+Urticina+crassicornis+-+its+primary+structure+and+phylogenetic+classification.">A new phospholipase A2 isolated from the sea anemone Urticina crassicornis - its primary structure and phylogenetic classification.</a> The FEBS Journal. 277 (12), 2641-2653 (2010).</li><li>Dennis, E. A., Cao, J., Hsu, Y. -. H., Magrioti, V., Kokotos, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phospholipase+A2+enzymes:+Physical+structure,+biological+function,+disease+implication,+chemical+inhibition,+and+therapeutic+intervention.">Phospholipase A2 enzymes: Physical structure, biological function, disease implication, chemical inhibition, and therapeutic intervention.</a> Chemical Reviews. 111 (10), 6130-6185 (2011).</li><li>Bradford, M. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+rapid+and+sensitive+method+for+the+quantitation+of+microgram+quantities+of+protein+utilizing+the+principle+of+protein-dye+binding.">A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding.</a> Analytical Biochemistry. 72, 248-254 (1976).</li><li>Kwon, Y. -. C., Jewett, M. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-throughput+preparation+methods+of+crude+extract+for+robust+cell-free+protein+synthesis.">High-throughput preparation methods of crude extract for robust cell-free protein synthesis.</a> Scientific Reports. 5, 8663 (2015).</li><li>Eno, A. E., Konya, R. S., Ibu, J. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biological+properties+of+a+venom+extract+from+the+sea+anemone,+Bunodosoma+cavernata.">Biological properties of a venom extract from the sea anemone, Bunodosoma cavernata.</a> Toxicon: Official Journal of the International Society on Toxinology. 36 (12), 2013-2020 (1998).</li><li>Morales-Landa, J. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antimicrobial,+antiprotozoal,+and+toxic+activities+of+Cnidarian+extracts+from+the+Mexican+Caribbean+Sea.">Antimicrobial, antiprotozoal, and toxic activities of Cnidarian extracts from the Mexican Caribbean Sea.</a> Pharmaceutical Biology. 45 (1), 37-43 (2007).</li><li>S&#225;nchez-Rodr&#237;guez, J., Cruz-Vazquez, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+and+biological+characterization+of+neurotoxic+compounds+from+the+sea+anemone+Lebrunia+danae+(Duchassaing+and+Michelotti,+1860).">Isolation and biological characterization of neurotoxic compounds from the sea anemone Lebrunia danae (Duchassaing and Michelotti, 1860).</a> Archives of Toxicology. 80 (7), 436-441 (2006).</li><li>de Oliveira, J. 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=Caissarolysin+I+(Bcs+I),+a+new+hemolytic+toxin+from+the+Brazilian+sea+anemone+Bunodosoma+caissarum:+purification+and+biological+characterization.">Caissarolysin I (Bcs I), a new hemolytic toxin from the Brazilian sea anemone Bunodosoma caissarum: purification and biological characterization.</a> Biochimica Et Biophysica Acta. 1760 (3), 453-461 (2006).</li><li>Norton, R. 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=Purification+and+characterisation+of+proteins+with+cardiac+stimulatory+and+haemolytic+activity+from+the+anemone+Actinia+tenebrosa.">Purification and characterisation of proteins with cardiac stimulatory and haemolytic activity from the anemone Actinia tenebrosa.</a> Toxicon: Official Journal of the International Society on Toxinology. 28 (1), 29-41 (1990).</li><li>Gondran, M., Eckeli, A. L., Migues, P. V., Gabilan, N. H., Rodrigues, A. L. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+crude+extract+from+the+sea+anemone,+Bunodosoma+caissarum+elicits+convulsions+in+mice:+possible+involvement+of+the+glutamatergic+system.">The crude extract from the sea anemone, Bunodosoma caissarum elicits convulsions in mice: possible involvement of the glutamatergic system.</a> Toxicon: Official Journal of the International Society on Toxinology. 40 (12), 1667-1674 (2002).</li><li>Dion, A. S., Pomenti, A. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ammoniacal+silver+staining+of+proteins:+mechanism+of+glutaraldehyde+enhancement.">Ammoniacal silver staining of proteins: mechanism of glutaraldehyde enhancement.</a> Analytical Biochemistry. 129 (2), 490-496 (1983).</li><li>Ram&#237;rez-Carreto, 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=Identification+of+a+pore-forming+protein+from+sea+anemone+Anthopleura+dowii+Verrill+(1869)+venom+by+mass+spectrometry.">Identification of a pore-forming protein from sea anemone Anthopleura dowii Verrill (1869) venom by mass spectrometry.</a> The Journal of Venomous Animals and Toxins Including Tropical Diseases. 25, 147418 (2019).</li><li>Nelson, G. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Studies+on+the+lipids+of+sheep+red+blood+cells.+I.+Lipid+composition+in+low+and+high+potassium+red+cells.">Studies on the lipids of sheep red blood cells. I. Lipid composition in low and high potassium red cells.</a> Lipids. 2 (1), 64-71 (1967).</li><li>Ram&#237;rez-Carreto, 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=Transcriptomic+and+proteomic+analysis+of+the+tentacles+and+mucus+of+Anthopleura+dowii+Verrill,+1869.">Transcriptomic and proteomic analysis of the tentacles and mucus of Anthopleura dowii Verrill, 1869.</a> Marine Drugs. 17 (8), 436 (2019).</li></ol>

The high demand for new compounds with applications in different fields of science and industry has led to the study of venom. Venom represents a rich source of molecules that serves as a template for generating new molecular tools. However, the complexity of these venoms requires the implementation and combination of various methods to obtain and study them.
Here, we show a method for obtaining and analyzing the venom of the sea anemone Anthopleura dowii, Verrill 1869, which can be u...

Marine animals are a rich source of biologically active compounds. In recent decades, the composition of sea anemone venom has attracted scientific attention since it comprises a diversity of polypeptides with hemolytic, cytotoxic, enzymatic (phospholipase, protease, chitinase), and neurotoxic activity and inhibitory effects on proteolytic activity1. In addition, these polypeptides are potential sources for the development of molecular tools in biotechnological and therapeutical use2,3.
There are few reports about sea anemone venom and its molecular components due to the complexity of obtaining the venom, even isolation, and characterization of toxins. The extraction methods used in the reports involved lysis and emptying the contents of cells that are related and unrelated to the venom production1.
A particular characteristic in all cnidarians is the absence of a system for production and release of the venom centralized in a single anatomical region. Instead, the nematocysts are structures that keep the venom4,5. Other types of cells, called epidermal gland cells, also secrete toxins and are also distributed throughout the body of sea anemones6.
The first and most crucial challenge in obtaining the venom is the generation of an extract with sufficient manipulation in subsequent processes, without the inactivation or degradation of labile proteins. Next, the cells must be lysed, and the components-in this case, polypeptides must be efficiently and quickly extracted, avoiding proteolysis and hydrolysis while eliminating other cellular components7.
Different methods are used to obtain the crude extract of a sea anemone; some involve sacrificing the organism while others allow it to be kept alive. Methods that imply the use of the organism&#180;s whole body allow for the release of most toxins from the venom8, compared to methods that keep organisms alive, which extract only some components of the venom9. The preparation of an extract requires evaluating the presence and potency of a substance of interest through a specific bioassay, which includes strategies to observe the pharmacological effects by in vivo or in vitro methods10.
Sea anemone venom contains cytolytic polypeptides, pore-forming toxins (PFTs)11, and phospholipases12; these molecules are models in the study of protein-lipid interaction, molecular tools in cancer therapy, and biosensors based on nanopore3. The classification of sea anemone PFTs is carried out according to their size or molecular weight, from 5 kDa to 80 kDa. The 20 kDa PFT, the most studied and known as actinoporins11, is of particular interest for its biomedical potential in the development of molecular tools for possible applications as anticancer, antimicrobial, and nanopore-based biosensors. Another cytolysin, including phospholipases, specifically phospholipase A2 (PLA2)13, releases a fatty acid due and hydrolyzes phospholipids, destabilizing the cell membrane. Due to this mechanism of action, PLA2 promises to be an essential model for the study and applications in inflammatory diseases. It could serve as a model for studies of lipid behavior in the cell membrane14.
Here, we describe an efficient protocol for obtaining the crude extract from sea anemone Anthopleura dowii Verrill, 1869, and detecting hemolysins and phospholipases. Both are relevant toxins that could be used as a template to design new molecular tools.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>15 mL conical centrifuge tube</td>
			<td>Corning</td>
			<td>430766</td>
			<td></td>
		</tr>
		<tr>
			<td>2-Bromophenol blue</td>
			<td>Sigma</td>
			<td>B75808</td>
			<td></td>
		</tr>
		<tr>
			<td>2-mercaptoetanol</td>
			<td>Sigma-Aldrich</td>
			<td>M6250-100ML</td>
			<td></td>
		</tr>
		<tr>
			<td>50 mL conical centrifuge tubes</td>
			<td>Corning</td>
			<td>430828</td>
			<td></td>
		</tr>
		<tr>
			<td>Acetic Acid Glacial</td>
			<td>J.T. Baker</td>
			<td>9515-03</td>
			<td></td>
		</tr>
		<tr>
			<td>Acrylamide</td>
			<td>Promega</td>
			<td>V3115</td>
			<td></td>
		</tr>
		<tr>
			<td>Agarose</td>
			<td>Promega</td>
			<td>V3125</td>
			<td></td>
		</tr>
		<tr>
			<td>Bisacrylamide</td>
			<td>Promega</td>
			<td>V3143</td>
			<td></td>
		</tr>
		<tr>
			<td>Bovine Serum Albumin Fraction V</td>
			<td>Sigma</td>
			<td>A3059-100G</td>
			<td></td>
		</tr>
		<tr>
			<td>Bradford Protein Assays</td>
			<td>Bio-Rad</td>
			<td>5000006</td>
			<td></td>
		</tr>
		<tr>
			<td>Calcium chloride</td>
			<td>Sigma-Aldrich</td>
			<td>C3306</td>
			<td></td>
		</tr>
		<tr>
			<td>Cell culture plates 96 well, V-bottom</td>
			<td>Corning</td>
			<td>3894</td>
			<td></td>
		</tr>
		<tr>
			<td>Centrifuge</td>
			<td>Eppendorf</td>
			<td>5804R</td>
			<td></td>
		</tr>
		<tr>
			<td>Centrifuge tubes</td>
			<td>Corning</td>
			<td>CLS430829</td>
			<td></td>
		</tr>
		<tr>
			<td>ChemiDoc MP system</td>
			<td>Bio-Rad</td>
			<td>1708280</td>
			<td></td>
		</tr>
		<tr>
			<td>Citric acid</td>
			<td>Sigma-Aldrich</td>
			<td>251275</td>
			<td></td>
		</tr>
		<tr>
			<td>Clear flat.bottom 96-Well Plates</td>
			<td>Thermo Scientific</td>
			<td>3855</td>
			<td></td>
		</tr>
		<tr>
			<td>Coomassie Brilliant Blue G-250</td>
			<td>Bio-Rad</td>
			<td>#1610406</td>
			<td></td>
		</tr>
		<tr>
			<td>Coomassie brilliant blue R-250</td>
			<td>Bio-Rad</td>
			<td>1610400</td>
			<td></td>
		</tr>
		<tr>
			<td>Dextrose</td>
			<td>J.T. Baker</td>
			<td>1916-01</td>
			<td></td>
		</tr>
		<tr>
			<td>Ductless Enclosure</td>
			<td>Labconco</td>
			<td>Vertical</td>
			<td>https://imagej.nih.gov/ij ImageJ 1.53c</td>
		</tr>
		<tr>
			<td>Gel Doc EZ</td>
			<td>Bio Rad.</td>
			<td></td>
			<td>Gel Documentation System</td>
		</tr>
		<tr>
			<td>Glycerol</td>
			<td>Sigma-Aldrich</td>
			<td>G5516-4L</td>
			<td></td>
		</tr>
		<tr>
			<td>Hemocytometer</td>
			<td>Marienfeld</td>
			<td>650030</td>
			<td></td>
		</tr>
		<tr>
			<td>ImageJ (Software)</td>
			<td>NIH, USA</td>
			<td>Version 1.53c</td>
			<td></td>
		</tr>
		<tr>
			<td>Incubator 211</td>
			<td>Labnet</td>
			<td>I5211 DS</td>
			<td></td>
		</tr>
		<tr>
			<td>Methanol</td>
			<td>J.T. Baker</td>
			<td>9049-03</td>
			<td></td>
		</tr>
		<tr>
			<td>Mini-PROTEAN tetra cell</td>
			<td>Bio-Rad</td>
			<td>1658000EDU</td>
			<td></td>
		</tr>
		<tr>
			<td>Na2HPO4</td>
			<td>J.T. Baker</td>
			<td>3824-01</td>
			<td></td>
		</tr>
		<tr>
			<td>NaCl</td>
			<td>J.T. Baker</td>
			<td>3624-01</td>
			<td></td>
		</tr>
		<tr>
			<td>NaH2PO4.H2O</td>
			<td>J.T. Baker</td>
			<td>3818-05</td>
			<td></td>
		</tr>
		<tr>
			<td>Origin software</td>
			<td></td>
			<td>version 9</td>
			<td>To design the plot with sigmoidal adjustments</td>
		</tr>
		<tr>
			<td>Petridish</td>
			<td>Falcon</td>
			<td>351007</td>
			<td></td>
		</tr>
		<tr>
			<td>Pipetman kit</td>
			<td>Gilson</td>
			<td>F167380</td>
			<td></td>
		</tr>
		<tr>
			<td>Precast mini gel</td>
			<td>BioRad</td>
			<td>1658004</td>
			<td></td>
		</tr>
		<tr>
			<td>Prestained Protein Ladder</td>
			<td>Thermo Scientific</td>
			<td>26620</td>
			<td></td>
		</tr>
		<tr>
			<td>Protease Inhibitor Cocktail</td>
			<td>Roche</td>
			<td>11836153001</td>
			<td></td>
		</tr>
		<tr>
			<td>Protein Assay Dye Reagent Concentrate</td>
			<td>Bio-Rad</td>
			<td>5000006</td>
			<td></td>
		</tr>
		<tr>
			<td>Rhodamine 6G</td>
			<td>Sigma-Aldrich</td>
			<td>252433</td>
			<td></td>
		</tr>
		<tr>
			<td>SDS</td>
			<td>Sigma-Aldrich</td>
			<td>L4509</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium citrate dihydrate</td>
			<td>JT Baker</td>
			<td>3646-01</td>
			<td></td>
		</tr>
		<tr>
			<td>Spectrophotometer</td>
			<td>THERMO SCIENTIFIC</td>
			<td>G10S UV-VIS</td>
			<td></td>
		</tr>
		<tr>
			<td>Tris Base</td>
			<td>Sigma-Aldrich</td>
			<td>77-86-1</td>
			<td></td>
		</tr>
		<tr>
			<td>Volt Power Supply</td>
			<td>Hoefer</td>
			<td>PS300B</td>
			<td></td>
		</tr>
	</tbody>
</table>

identification of hemolytic and phospholipase activity in crude extracts from sea anemones by straightforward bioassays

Sea anemone venom composition includes polypeptide and non-proteins molecules. Cytolytic components have a high biotechnological and biomedical potential for designing new molecular tools. Sea anemone venom locates in glandular cells from ectoderm and sub-cellular structures called nematocysts, both of which are distributed throughout the sea anemone body. This characteristic implies challenges because the cells and nematocyst must be lysed to release the venom components with other non-toxic molecules. Therefore, first, the venom is derived from a crude extract (mixture of different and diverse molecules and tissue debris). The next step is to detect polypeptides with specific bioactivities. Here, we describe an efficient strategy to obtain the sea anemone crude extract and bioassay to identify the presence of cytolysins. The first step involves inexpensive and straightforward techniques (stirred and freeze-thaw cycle) to release cytolysins. We obtained the highest cytolytic activity and protein (~500 mg of protein from 20 g of dry weight). Next, the polypeptide complexity of the extract was analyzed by SDS-PAGE gel detecting proteins with molecular weights between 10 kDa and 250 kDa. In the hemolytic assay, we used sheep red blood cells and determined HU50 (11.1 &plusmn; 0.3 &#181;g/mL). In contrast, the presence of phospholipases in the crude extract was determined using egg yolk as a substrate in a solid medium with agarose. Overall, this study uses an efficient and inexpensive protocol to prepare the crude extract and applies replicable bioassays to identify cytolysins, molecules with biotechnological and biomedical interests.

The representative results of the protocol used to obtain the crude extract of sea anemone showed that combining two techniques (agitation and cycles of freezing and thawing) produced an efficient discharge of nematocysts, and the total amount of protein was 500 mg (8 mg/mL) (Figure 3).
The crude extract&#39;s protein complexity could be observed from 10 kDa and greater than 250 kDa through SDS-PAGE electrophoresis. In addition, cytolysins were detected in the mol...

Watch this Scientific Journal Video about Identification of Hemolytic and Phospholipase Activity in Crude Extracts from Sea Anemones by Straightforward Bioassays at JoVE.com

Identification of Hemolytic and Phospholipase Activity in Crude Extracts from Sea Anemones by Straightforward Bioassays

Here, we describe a protocol to obtain crude venom extract from sea anemone and detect its hemolytic and phospholipase activity.

Sea anemone venom composition includes polypeptide and non-proteins molecules. Cytolytic components have a high biotechnological and biomedical potential ...

Sea anemone toxin interaction must use the least number of organisms and efficient protocols to obtain great diversity and abundance of the toxins and fast identification of a specific toxin. We combined two efficient techniques to prepare the crude extract with a high amount of protein and describe reproducible, specific, fast, and inexpensive assays to identify hemolysis and phospholic bases in the sea anemone venom. The method can be used in almost any example that is decided to identify one or both types of cytolysins.The method's efficiency is achieved by taking care of the times in each step while preparing the crude extract. The key to hemolysis is careful handling of the erythrocyte to avoid mechanical lysis, and in phospholysis assay, taking care of the temperature in the preparation of the plate. Demonstrating the procedure will be Dr.Santos Ramirez-Carreto, biologist Sandra Salazar Garcia, and biologist Giovanni Macias Martinez from my laboratory.Begin by cleaning the collected sea anemone A.doi with distilled water by hand to remove the big substrate particles adhering to the body. Immediately freeze the organisms at minus 80 degrees Celsius in an ultrafreezer for 72 hours. Then, place the organisms in special glasses for freeze drying with lyophilization conditions for 48 hours.For tissue hydration, reconstitute 20 grams dry weight of lyophilized organisms with 60 milliliters of 50-millimolar sodium phosphate buffer and one inhibitor cocktail tablet. In a magnetic stirrer, continuously stir the sample at around 800 RPM and four degrees Celsius for 12 hours. After freezing the sample at minus 20 degrees Celsius for 12 hours to induce cell lysis and nematocyst discharge, place the container in water at room temperature until it thaws up to 90%Repeat this procedure three times.To clarify the extract, centrifuge the sample at 25, 400 times G for 40 minutes at four degrees Celsius. Recover the supernatant and centrifuge it again. Repeat the step three to four times and recover the supernatant at last.The recovered supernatant or crude extract contains the venom components and other cell molecules such as lipids, carbohydrates and nucleic acids. Determine the protein concentration of the crude extract using a commercial Bradford colorimetric assay kit. Incubate the samples for five minutes at room temperature without shaking.Then, measure the absorbance at 595 nanometers. Plot the averages of the sample BSA absorbances and determine the equation of the graph where y is the absorbance, m is the slope of the line, x is the protein concentration, and b is the ordinate to the origin. To analyze the crude extract, add 30 micrograms of the crude extract to five microliters of the protein loading buffer to denature the proteins.The final volume must be less than 50 microliters. Run electrophoresis at 25 milliamperes constant for one hour and 30 minutes. To avoid the diffusion of the gel proteins, add the fixation solution to the proteins and incubate at room temperature for 40 minutes with shaking at 80 RPM.Then, decant the solution and add the protein crosslinking solution. Incubate for 30 minutes at room temperature with shaking at 80 RPM. Remove the solution and wash the gel with 100 milliliters of distilled water for five minutes.After that, remove the water and repeat this procedure four times. Carry out protein staining with 50 milliliters of Coomassie Brilliant Blue R-250 filtered solution stirring at 60 RPM in a laboratory rotary oscillator at room temperature for 15 minutes. Extract one milliliter of blood from the jugular vein of a sheep and remove the needle from the syringe.Immediately drain blood into a tube with 50 milliliters of Alsever solution and centrifuge at 804 times G for five minutes at four degrees Celsius. Discard the supernatant and add 30 milliliters of Alsever solution by sliding it along the tube's inner walls. Slowly resuspend the pellet using a Pasteur plastic pipette and centrifuge the solution again at 804 times G for five minutes at four degrees Celsius.Repeat this procedure until the supernatant is clarified. Maintain the final volume of the Alsever solution to achieve a concentration of 2 million cells per milliliter approximately. Then, use a Neubauer chamber or hemocytometer to count the cells.Incubate the solution mixtures for one hour at 37 degrees Celsius without shaking and then centrifuge the plate at 804 times G for five minutes at four degrees Celsius. Recover the supernatant in another 96-well plate with a flat bottom. If the crude extract contains cytolysins, erythrocytes will lyse and release hemoglobin.Read the absorbance at 415 nanometers and calculate the amount of extract that produces hemolysis in 50%of the erythrocytes. Increase the amount of sea anemone crude extract and design the plot with sigmoidal adjustments using appropriate software. Wash one chicken egg with 1%SDS in distilled water and separate the egg yolk from the egg white under sterile conditions.Prepare solutions A, B, C, and D.Add 500 microliters of solutions A and C to solution B and 100 microliters of solution D.Mix them and pour 25 milliliters into each Petri dish. Wait for the solution to solidify under sterile conditions and make wells of approximately two to three millimeters in diameter with a thin tube. Add a total of 20 microliters of phosphate buffer as a negative control in one well and 20 microliters of a determined phospholipase as a positive control in another well.Place different amounts of the crude extract protein 5, 15, 25, 35, and 45 micrograms in the remaining wells, each in a final volume of 20 microliters. Incubate at 37 degrees Celsius for 20 hours. The representative results of the protocol used to obtain the crude extract of sea anemone showed that combining two techniques, agitation and cycles of freezing and thawing, produced an efficient discharge of nematocysts.The nematocytes before and after stimuli are shown here. The nematocyst tubule is exposed in this image, indicating the toxin release. The electrophoretic profile of sea anemone crude extract is shown here.The sea anemone crude extract was analyzed by SDS-PAGE 15%polyacrylamide gel and showed protein from 10 kilodaltons to 250 kilodaltons of molecular weight. Here, lane 1 is the protein ladder and lane 2 is sea anemone venom. Cytolysins were detected in the molecular weight zone of 15 kilodaltons and 20 kilodaltons.Shown here is the hemolysis assay in erythrocytes from sheep. The hemolytic activity of the extract before and during the freezing and thawing cycles increased until 100%hemolysis was reached with 50 micrograms of the total crude extract protein in the last two cycles. The amount needed to lyse 50%sheep erythrocytes is 11.1 0.3 micrograms per milliliter.Phospholipase activity was detected by the formation of clear halos in the areas of the agar plate where the crude extract sample was applied. The results show the presence of phospholipase activity from 15 micrograms of total protein. The diameter of the halo increased in a dose-dependent manner;that is, if the amount of crude extract increased, the diameter of the halo increased.While attempting the procedure, make sure to induce nematocyst discharge, quantitate the total protein, analyze crude extract by SDS-PAGE electrophoresis, calculate the amount of crude extract protein to produce 50%of hemolysis, and use different amounts of protein in phospholipase assay. We can analyze the crude extract by proteomic technique to identify polypeptides with great relevance in biotechnology and biomedicine, even profile and characterize a unique molecule and then produce it in the laboratory for an application. We obtained part of the sequence of a performing protein with antitumor activity in the human obdurate lung carcinoma epithelial cells.Likewise, we identify the sequence of phospholipases of biotechnological interest.

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Research

JoVE Journal

Biochemistry

Identification of Small Molecule-binding Proteins in a Native Cellular Environment by Live-cell Photoaffinity Labeling

Identifying the molecular target(s) of small molecules is a challenging but necessary step towards understanding their mechanism of action. While several target identification methods have been developed and used to successfully elucidate the binding proteins of a variety of small molecules, these techniques have drawbacks that make them unsuitable for detecting certain types of small molecule-target interactions. In particular, non-covalent interactions that depend on native cellular conditions, such as those of membrane proteins whose structures may be perturbed upon cell lysis, are often not amenable to affinity-based target identification methods. Here, we demonstrate a method wherein a probe containing a photolabile group is used to covalently crosslink to the small molecule binding protein within the environment of the live cell, allowing the detection and isolation of the target protein without the need for maintenance of the interaction after cell lysis. This technique is a valuable tool for studying biologically interesting small molecules with unknown mechanisms, both in the context of basic biology as well as drug discovery.

We describe here a method for identification of small molecule-binding proteins using photoaffinity labeling. The advantage of this technique is that binding and covalent labeling of the target proteins occurs within the live cellular environment, removing the risk of disrupting native protein structure and binding conditions upon cell lysis.

Identifying the molecular target(s) of small molecules is a challenging but necessary step towards understanding their mechanism of action. While several ...

Defining Substrate Specificities for Lipase and Phospholipase Candidates

Microorganisms produce a wide spectrum of (phospho)lipases that are secreted in order to make external substrates available for the organism. Alternatively, other (phospho)lipases may be physically associated with the producing organism causing a turnover of intrinsic lipids and frequently giving rise to a remodeling of the cellular membranes. Although potential (phospho)lipases can be predicted with a number of algorithms when the gene/protein sequence is available, experimental proof of the enzyme activities, substrate specificities, and potential physiological functions has frequently not been obtained. This manuscript describes the optimization of assay conditions for prospective (phospho)lipases with unknown substrate specificities and how to employ these optimized conditions in the search for the natural substrate of a respective (phospho)lipase. Using artificial chromogenic substrates, such as p-nitrophenyl derivatives, may help to detect a minor enzymatic activity for a predicted (phospho)lipase under standard conditions. Having encountered such a minor enzymatic activity, the distinct parameters of an enzyme assay can be varied in order to obtain a more efficient hydrolysis of the artificial substrate. After having determined the conditions under which an enzyme works well, a variety of potential natural substrates should be assayed for their degradation, a process that can be followed employing distinct chromatographic methods. The definition of substrate specificities for new enzymes, often provides hypotheses for a potential physiological role of these enzymes, which then can be tested experimentally. Following these guidelines, we were able to identify a phospholipase C (SMc00171) that degrades phosphatidylcholine to phosphocholine and diacylglycerol, in a crucial step for the remodeling of membranes in the bacterium Sinorhizobium meliloti upon phosphorus-limiting conditions of growth. For two predicted patatin-like phospholipases (SMc00930 and SMc01003) of the same organism, we could redefine their substrate specificities and clarify that SMc01003 is a diacylglycerol lipase.

Many predicted (phospho)lipases are poorly characterized with regard to their substrate specificities and physiological functions. Here we provide a protocol to optimize enzyme activities, search for natural substrates, and propose physiological functions for these enzymes.

Microorganisms produce a wide spectrum of (phospho)lipases that are secreted in order to make external substrates available for the organism. ...

Sample Preparation for Mass Spectrometry-based Identification of RNA-binding Regions

Noncoding RNAs play important roles in several nuclear processes, including regulating gene expression, chromatin structure, and DNA repair. In most cases, the action of noncoding RNAs is mediated by proteins whose functions are in turn regulated by these interactions with noncoding RNAs. Consistent with this, a growing number of proteins involved in nuclear functions have been reported to bind RNA and in a few cases the RNA-binding regions of these proteins have been mapped, often through laborious, candidate-based methods.
Here, we report a detailed protocol to perform a high-throughput, proteome-wide unbiased identification of RNA-binding proteins and their RNA-binding regions. The methodology relies on the incorporation of a photoreactive uridine analog in the cellular RNA, followed by UV-mediated protein-RNA crosslinking, and mass spectrometry analyses to reveal RNA-crosslinked peptides within the proteome. Although we describe the procedure for mouse embryonic stem cells, the protocol should be easily adapted to a variety of cultured cells.

We describe a protocol to identify RNA-binding proteins and map their RNA-binding regions in live cells using UV-mediated photocrosslinking and mass spectrometry.

Noncoding RNAs play important roles in several nuclear processes, including regulating gene expression, chromatin structure, and DNA repair. In most ...

Preparation of Keratin Hydrolysate from Chicken Feathers and Its Application in Cosmetics

Keratin hydrolysates (KHs) are established standard components in hair cosmetics. Understanding the moisturizing effects of KH is advantageous for skin-care cosmetics. The goals of the protocol are: (1) to process chicken feathers into KH by alkaline-enzymatic hydrolysis and purify it by dialysis, and (2) to test if adding KH into an ointment base (OB) increases hydration of the skin and improves skin barrier function by diminishing transepidermal water loss (TEWL). During alkaline-enzymatic hydrolysis feathers are first incubated at a higher temperature in an alkaline environment and then, under mild conditions, hydrolyzed with proteolytic enzyme. The solution of KH is dialyzed, vacuum dried, and milled to a fine powder. Cosmetic formulations comprising from oil in water emulsion (O/W) containing 2, 4, and 6 weight% of KH (based on the weight of the OB) are prepared. Testing the moisturizing properties of KH is carried out on 10 men and 10 women at time intervals of 1, 2, 3, 4, 24, and 48 h. Tested formulations are spread at degreased volar forearm sites. The skin hydration of stratum corneum (SC) is assessed by measuring capacitance of the skin, which is one of the most world-wide used and simple methods. TEWL is based on measuring the quantity of water transported per a defined area and period of time from the skin. Both methods are fully non-invasive. KH makes for an excellent occlusive; depending on the addition of KH into OB, it brings about a 30% reduction in TEWL after application. KH also functions as a humectant, as it binds water from the lower layers of the epidermis to the SC; at the optimum KH addition in the OB, up to 19% rise in hydration in men and 22% rise in women occurs.

The goal of the protocol is to prepare keratin hydrolysate from chicken feathers by alkaline-enzymatic hydrolysis and to test whether adding keratin hydrolysate into a cosmetics ointment base improves skin barrier function (heightening hydration and diminishing transepidermal water loss). Tests are conducted on men and woman volunteers.

Keratin hydrolysates (KHs) are established standard components in hair cosmetics. Understanding the moisturizing effects of KH is advantageous for ...

Isolation and Respiratory Measurements of Mitochondria from Arabidopsis thaliana

Mitochondria are essential organelles involved in numerous metabolic pathways in plants, most notably the production of adenosine triphosphate (ATP) from the oxidation of reduced compounds such as nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FADH2). The complete annotation of the Arabidopsis thaliana genome has established it as the most widely used plant model system, and thus the need to purify mitochondria from a variety of organs (leaf, root, or flower) is necessary to fully utilize the tools that are now available for Arabidopsis to study mitochondrial biology. Mitochondria are isolated by homogenization of the tissue using a variety of approaches, followed by a series of differential centrifugation steps producing a crude mitochondrial pellet that is further purified using continuous colloidal density gradient centrifugation. The colloidal density material is subsequently removed by multiple centrifugation steps. Starting from 100 g of fresh leaf tissue, 2 - 3 mg of mitochondria can be routinely obtained. Respiratory experiments on these mitochondria display typical rates of 100 - 250 nmol O2 min-1 mg total mitochondrial protein-1 (NADH-dependent rate) with the ability to use various substrates and inhibitors to determine which substrates are being oxidized and the capacity of the alternative and cytochrome terminal oxidases. This protocol describes an isolation method of mitochondria from Arabidopsis thaliana leaves using continuous colloidal density gradients and an efficient respiratory measurements of purified plant mitochondria.

Isolation and Respiratory Measurements of Mitochondria from Arabidopsis thaliana

As mitochondria are only a small percentage of the plant cell, they need to be purified for a range of studies. Mitochondria can be isolated from a variety of plant organs by homogenization, followed by differential and density gradient centrifugation to obtain a highly purified mitochondrial fraction.

Mitochondria are essential organelles involved in numerous metabolic pathways in plants, most notably the production of adenosine triphosphate (ATP) from ...

The Determination of Protease Specificity in Mouse Tissue Extracts by MALDI-TOF Mass Spectrometry: Manipulating PH to Cause Specificity Changes

Proteases have several biological functions, including protein activation/inactivation and food digestion. Identifying protease specificity is important for revealing protease function. The method proposed in this study determines protease specificity by measuring the molecular weight of unique substrates using Matrix-assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) mass spectrometry. The substrates contain iminobiotin, while the cleaved site consists of amino acids, and the spacer consists of polyethylene glycol. The cleaved substrate will generate a unique molecular weight using a cleaved amino acid. One of the merits of this method is that it may be carried out in one pot using crude samples, and it is also suitable for assessing multiple samples. In this article, we describe a simple experimental method optimized with samples extracted from mouse lung tissue, including tissue extraction, placement of digestive substrates into samples, purification of digestive substrates under different pH conditions, and measurement of the substrates&#39; molecular weight using MALDI-TOF mass spectrometry. In summary, this technique allows for the identification of protease specificity in crude samples derived from tissue extracts using MALDI-TOF mass spectrometry, which may easily be scaled up for multiple sample processing.

Here, we present a protocol to determine protease specificity in crude mouse tissue extracts using MALDI-TOF spectrometry.

Proteases have several biological functions, including protein activation/inactivation and food digestion. Identifying protease specificity is important ...

Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay

Cyclin-dependent kinase 1 (Cdk1) is a master controller for the cell cycle in all eukaryotes and phosphorylates an estimated 8 - 13% of the proteome; however, the number of identified targets for Cdk1, particularly in human cells is still low. The identification of Cdk1-specific phosphorylation sites is important, as they provide mechanistic insights into how Cdk1 controls the cell cycle. Cell cycle regulation is critical for faithful chromosome segregation, and defects in this complicated process lead to chromosomal aberrations and cancer.
Here, we describe an in vitro kinase assay that is used to identify Cdk1-specific phosphorylation sites. In this assay, a purified protein is phosphorylated in vitro by commercially available human Cdk1/cyclin B. Successful phosphorylation is confirmed by SDS-PAGE, and phosphorylation sites are subsequently identified by mass spectrometry. We also describe purification protocols that yield highly pure and homogeneous protein preparations suitable for the kinase assay, and a binding assay for the functional verification of the identified phosphorylation sites, which probes the interaction between a classical nuclear localization signal (cNLS) and its nuclear transport receptor karyopherin &#945;. To aid with experimental design, we review approaches for the prediction of Cdk1-specific phosphorylation sites from protein sequences. Together these protocols present a very powerful approach that yields Cdk1-specific phosphorylation sites and enables mechanistic studies into how Cdk1 controls the cell cycle. Since this method relies on purified proteins, it can be applied to any model organism and yields reliable results, especially when combined with cell functional studies.

Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay

Cyclin-dependent kinase 1 (Cdk1) is activated in the G2 phase of the cell cycle and regulates many cellular pathways. Here, we present a protocol for an in vitro kinase assay with Cdk1, which allows the identification of Cdk1-specific phosphorylation sites for establishing cellular targets of this important kinase.

Cyclin-dependent kinase 1 (Cdk1) is a master controller for the cell cycle in all eukaryotes and phosphorylates an estimated 8 - 13% of the proteome; ...

The Identification of Sea Lamprey Pheromones Using Bioassay-Guided Fractionation

Bioassay-guided fractionation is an iterative approach that uses the results of physiological and behavioral bioassays to guide the isolation and identification of an active pheromone compound. This method has resulted in the successful characterization of the chemical signals that function as pheromones in a wide range of animal species. Sea lampreys rely on olfaction to detect pheromones that mediate behavioral or physiological responses. We use this knowledge of fish biology to posit functions of putative pheromones and to guide the isolation and identification of active pheromone components. Chromatography is used to extract, concentrate, and separate compounds from the conditioned water. Electro-olfactogram (EOG) recordings are conducted to determine which fractions elicit olfactory responses. Two-choice maze behavioral assays are then used to determine if any of the odorous fractions are also behaviorally active and induce a preference. Spectrometric and spectroscopic methods provide the molecular weight and structural information to assist with the structure elucidation. The bioactivity of the pure compounds is confirmed with EOG and behavioral assays. The behavioral responses observed in the maze should ultimately be validated in a field setting to confirm their function in a natural stream setting. These bioassays play a dual role to 1) guide the fractionation process and 2) confirm and further define the bioactivity of isolated components. Here, we report the representative results of a sea lamprey pheromone identification that exemplify the utility of the bioassay-guided fractionation approach. The identification of sea lamprey pheromones is particularly important because a modulation of its pheromone communication system is among the options considered to control the invasive sea lamprey in the Laurentian Great Lakes. This method can be readily adapted to characterize the chemical communication in a broad array of taxa and shed light on waterborne chemical ecology.

Here, we present a protocol to isolate and characterize the structure, olfactory potency, and behavioral response of putative pheromone compounds of sea lampreys.

Bioassay-guided fractionation is an iterative approach that uses the results of physiological and behavioral bioassays to guide the isolation and ...

Detection of Phospholipase C Activity in the Brain Homogenate from the Honeybee

The honeybee is a model organism for evaluating complex behaviors and higher brain function, such as learning, memory, and division of labor. The mushroom body (MB) is a higher brain center proposed to be the neural substrate of complex honeybee behaviors. Although previous studies identified genes and proteins that are differentially expressed in the MBs and other brain regions, the activities of the proteins in each region are not yet fully understood. To reveal the functions of these proteins in the brain, pharmacologic analysis is a feasible approach, but it is first necessary to confirm that pharmacologic manipulations indeed alter the protein activity in these brain regions.
We previously identified a higher expression of genes encoding phospholipase C (PLC) in the MBs than in other brain regions, and pharmacologically assessed the involvement of PLC in honeybee behavior. In that study, we biochemically tested two pharmacologic agents and confirmed that they decreased PLC activity in the MBs and other brain regions. Here, we present a detailed description of how to detect PLC activity in honeybee brain homogenate. In this assay system, homogenates derived from different brain regions are reacted with a synthetic fluorogenic substrate, and fluorescence resulting from PLC activity is quantified and compared between brain regions. We also describe our evaluation of the inhibitory effects of certain drugs on PLC activity using the same system. Although this system is likely affected by other endogenous fluorescence compounds and/or the absorbance of the assay components and tissues, the measurement of PLC activity using this system is safer and easier than that using the traditional assay, which requires radiolabeled substrates. The simple procedure and manipulations allow us to examine PLC activity in the brains and other tissues of honeybees involved in different social tasks.

To test the inhibitory effects of pharmacologic agents on phospholipase C (PLC) in different regions of the honeybee brain, we present a biochemical assay to measure PLC activity in those regions. This assay could be useful for comparing PLC activity among tissues, as well as among bees exhibiting different behaviors.

The honeybee is a model organism for evaluating complex behaviors and higher brain function, such as learning, memory, and division of labor. The mushroom ...

Quantification of Hypopigmentation Activity In Vitro

This study presents laboratory methods for the quantification of hypopigmentation activity in vitro. Melanin, the major pigment in melanocytes, is synthesized in response to multiple cellular and environmental factors. Melanin protects skin cells from ultraviolet damage, but also has biophysical and biochemical functions. Excessive production or accumulation of melanin in melanocytes can cause dermatological problems, such as freckles, dark spots, melasma, and moles. Therefore, the control of melanogenesis with hypopigmentation agents is important in individuals with clinical or cosmetic needs. Melanin is primarily synthesized in the melanosomes of melanocytes in a complex biochemical process called melanogenesis, which is influenced by extrinsic and intrinsic factors, such as hormones, inflammation, age, and ultraviolet light exposure. We describe three methods to determine the hypopigmentation activity of chemicals or natural substances in melanocytes: measurement of the 1) cellular tyrosinase activity and 2) melanin content, and 3) staining and quantifying cellular melanin with image analysis.
In melanogenesis, tyrosinase catalyzes the rate-limiting step that converts L-tyrosine into 3,4-dihydroxyphenylalanine (L-DOPA) and then into dopaquinone. Therefore, the inhibition of tyrosinase is a primary hypopigmentation mechanism. In cultured melanocytes, tyrosinase activity can be quantified by adding L-DOPA as a substrate and measuring dopaquinone production by spectrophotometry. Melanogenesis can also be measured by quantifying the melanin content. The melanin-containing cellular fraction is extracted with NaOH and melanin is quantified spectrophotometrically. Finally, the melanin content can be quantified by image analysis following Fontana-Masson staining of melanin. Although the results of these in vitro assays may not always be reproduced in human skin, these methods are widely used in melanogenesis research, especially as the initial step to identify potential hypopigmentation activity. These methods can also be used to assess melanocyte activity, growth, and differentiation. Consistent results with the three different methods ensure the validity of the effects.

We describe three experimental methods for evaluating the hypopigmentation activity of chemicals in vitro: quantification of 1) cellular tyrosinase activity and 2) melanin content, and 3) measurement of melanin by cellular melanin staining and image analysis.