Name: quantification of hypopigmentation activity in vitro
Uploaded: 2019-03-06T12:30:00
Description: Watch this Scientific Journal Video about Quantification of Hypopigmentation Activity In Vitro at JoVE.com

Detta arbete stöddes av Korea Institute i planeringen och utvärderingen för teknik i livsmedel, jordbruk och skogsbruk (IPET) genom programmet Agri-bioindustri teknik utveckling, finansierade av ministeriet för jordbruk, livsmedel och landsbygdens frågor (MAFRA ) (116159-02-2-WT011) och skolan av biovetenskap och bioteknik för BK21 PLUS, Korea University.

1. beredning av Medium, föreningar och reagenser
<ol><li>Förbered B16F10 komplett odlingsmedium. Tillägg Dulbecco's modified örnens medium (DMEM) med 10% fetalt bovint serum (FBS) och 1% penicillin/streptomycin (SKADEDJUR).<ol>
<li>För att göra 500 mL komplett medium, blanda 445 mL Dulbeccos modifierade örnens medium (DMEM) med 50 mL FBS och 5 mL av PEST i en steriliserad 1 L glasflaska. Efter blandning försiktigt, filtrera medium genom ett 0,2 µm flaska-top filter till en ny steriliserad glasflaska och sedan ...

<ol>
	<li>Bonaventure, J., Domingues, M. J., Larue, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cellular+and+molecular+mechanisms+controlling+the+migration+of+melanocytes+and+melanoma+cells.">Cellular and molecular mechanisms controlling the migration of melanocytes and melanoma cells.</a> Pigment Cell &amp; Melanoma Research. 26 (3), 316-325 (2013).</li><li>Brenner, M., Hearing, V. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+protective+role+of+melanin+against+UV+damage+in+human+skin.">The protective role of melanin against UV damage in human skin.</a> Photochemistry and Photobiology. 84 (3), 539-549 (2008).</li><li>Galvan, I., Solano, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Melanin+chemistry+and+the+ecology+of+stress.">Melanin chemistry and the ecology of stress.</a> Physiological and Biochemical Zoology. 88 (3), 352-355 (2015).</li><li>Burger, P., Landreau, A., Azoulay, S., Michel, T., Fernandez, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Skin+whitening+cosmetics:+Feedback+and+challenges+in+the+development+of+natural+skin+lighteners.">Skin whitening cosmetics: Feedback and challenges in the development of natural skin lighteners.</a> Cosmetics. 3 (4), 36 (2016).</li><li>Cooksey, C. 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=Evidence+of+the+indirect+formation+of+the+catecholic+intermediate+substrate+responsible+for+the+autoactivation+kinetics+of+tyrosinase.">Evidence of the indirect formation of the catecholic intermediate substrate responsible for the autoactivation kinetics of tyrosinase.</a> Journal of Biological Chemistry. 272 (42), 26226-26235 (1997).</li><li>Ando, H., Kondoh, H., Ichihashi, M., Hearing, V. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Approaches+to+identify+inhibitors+of+melanin+biosynthesis+via+the+quality+control+of+tyrosinase.">Approaches to identify inhibitors of melanin biosynthesis via the quality control of tyrosinase.</a> Journal of Investigative Dermatology. 127 (4), 751-761 (2007).</li><li>Gillbro, J. M., Olsson, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+melanogenesis+and+mechanisms+of+skin-lightening+agents+-+existing+and+new+approaches.">The melanogenesis and mechanisms of skin-lightening agents - existing and new approaches.</a> International Journal of Cosmetic Science. 33 (3), 210-221 (2011).</li><li>Passeron, T., Coelho, S. G., Miyamura, Y., Takahashi, K., Hearing, V. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immunohistochemistry+and+in+situ+hybridization+in+the+study+of+human+skin+melanocytes.">Immunohistochemistry and in situ hybridization in the study of human skin melanocytes.</a> Experimental Dermatology. 16 (3), 162-170 (2007).</li><li>Lee, J. H., 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=Momilactione+B+inhibits+protein+kinase+A+signaling+and+reduces+tyrosinase-related+proteins+1+and+2+expression+in+melanocytes.">Momilactione B inhibits protein kinase A signaling and reduces tyrosinase-related proteins 1 and 2 expression in melanocytes.</a> Biotechnology Letters. 34 (5), 805-812 (2012).</li><li>Jun, H. 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=Dual+inhibitions+of+lemon+balm+(Melissa+officinalis)+ethanolic+extract+on+melanogenesis+in+B16-F1+murine+melanocytes:+inhibition+of+tyrosinase+activity+and+its+gene+expression.">Dual inhibitions of lemon balm (Melissa officinalis) ethanolic extract on melanogenesis in B16-F1 murine melanocytes: inhibition of tyrosinase activity and its gene expression.</a> Food Science and Biotechnology. 20 (4), 1051-1059 (2011).</li><li>Jun, H. 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=p-Coumaric+acid+inhibition+of+CREB+phosphorylation+reduces+cellular+melanogenesis.">p-Coumaric acid inhibition of CREB phosphorylation reduces cellular melanogenesis.</a> European Food Research and Technology. 235 (6), 1207-1211 (2012).</li><li>Jun, H. 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=Dual+inhibition+of+&#947;-oryzanol+on+cellular+melanogenesis:+inhibition+of+tyrosinase+activity+and+reduction+of+melanogenic+gene+expression+by+a+protein+kinase+a-dependent+mechanism.">Dual inhibition of &#947;-oryzanol on cellular melanogenesis: inhibition of tyrosinase activity and reduction of melanogenic gene expression by a protein kinase a-dependent mechanism.</a> Journal of Natural Products. 75 (10), 1706-1711 (2012).</li><li>Choi, Y. 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=Effects+of+the+isoflavone+puerarin+and+its+glycosides+on+melanogenesis+in+B16+melanocytes.">Effects of the isoflavone puerarin and its glycosides on melanogenesis in B16 melanocytes.</a> European Food Research and Technology. 231 (1), 75-83 (2010).</li><li>Cho, B. R., Jun, H. J., Thach, T. T., Wu, C., Lee, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Betaine+reduces+cellular+melanin+content+via+suppression+of+microphthalmia-associated+transcription+factor+in+B16-F1+murine+melanocytes.">Betaine reduces cellular melanin content via suppression of microphthalmia-associated transcription factor in B16-F1 murine melanocytes.</a> Food Science and Biotechnology. 26 (5), 1391-1397 (2017).</li><li>Overwijk, W. W., Restifo, N. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=B16+as+a+mouse+model+for+human+melanoma.">B16 as a mouse model for human melanoma.</a> Current Protocols in Immunology. , (2001).</li><li>Virador, V. M., Kobayashi, N., Matsunaga, J., Hearing, V. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+standardized+protocol+for+assessing+regulators+of+pigmentation.">A standardized protocol for assessing regulators of pigmentation.</a> Analytical Biochemistry. 270 (2), 207-219 (1999).</li><li>D'Mello, S. A. N., Finlay, G. J., Baguley, B. C., Askarian-Amiri, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Signaling+pathways+in+melanogenesis.">Signaling pathways in melanogenesis.</a> International Journal of Molecular Sciences. 17 (7), 1144 (2016).</li><li>Hou, L., Panthier, J. J., Arnheiter, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Signaling+and+transcriptional+regulation+in+the+neural+crest-derived+melanocyte+lineage:+interactions+between+KIT+and+MITF.">Signaling and transcriptional regulation in the neural crest-derived melanocyte lineage: interactions between KIT and MITF.</a> Development. 127 (24), 5379-5389 (2000).</li><li>Hedley, S. J., Gawkrodger, D. J., Weetman, A. P., MacNeil, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=&#945;-MSH+and+melanogenesis+in+normal+human+adult+melanocytes.">&#945;-MSH and melanogenesis in normal human adult melanocytes.</a> Pigment Cell Research. 11 (1), 45-56 (1998).</li><li>Hu, D. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Methodology+for+evaluation+of+melanin+content+and+production+of+pigment+cells+in+vitro.">Methodology for evaluation of melanin content and production of pigment cells in vitro.</a> Photochemistry and Photobiology. 84 (3), 645-649 (2008).</li><li>Carriel, V. 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=A+novel+histochemical+method+for+a+simultaneous+staining+of+melanin+and+collagen+fibers.">A novel histochemical method for a simultaneous staining of melanin and collagen fibers.</a> Journal of Histochemistry &amp; Cytochemistry. 59 (3), 270-277 (2011).</li></ol>

Vi presenterade protokoll för att utvärdera aktiviteten hypopigmentering av test föreningar använder odlade melanocyter. De representativa resultat visade hypopigmentering effekten av arbutin, en tyrosinas-hämmare som hämmade tyrosinase aktivitet och cellulära melanin-halt. Dessa metoder används i anti-melanogenic aktivitet forskning. Med dessa testmetoder, vi har också framgångsrikt identifierat flera bioaktiva föreningar som har melanogenes hämmande effekter på B16F10 celler tidigare decennium<sup class="x...

Melanin spelar en avgörande roll i fysiologi, patologi och toxikologin hos flera organ inklusive hud, ögon och hjärna1. De viktigaste funktionerna av melanin är foto-screening och biokemiska effekter. Melanin absorberar infrarött och synliga ljus samt ultraviolett (UV) strålning, ökad absorption priser på kortare våglängder av ljus; Således, melanin skyddar vävnader från skador orsakade av synligt ljus eller UV strålning2. Melanin är en antioxidant och har en affinitet för metaller och andra giftiga kemikalier; Därför kan det skydda vävnader från oxidativ och kemisk stress3. Men orsakar överproduktion av melanin dermatologiska problem.
Kvantitet och kvalitet av melanin i huden och iris är de viktigaste faktorerna för färgen på iris och huden. Individer kan ha olika hud färg preferenser; några gynnar solbrun hud, medan andra föredrar ljusare hudfärger. Beroende på dessa konsumenten profiler, har hypopigmentering kosmetika utvecklats för att tillgodose enskilda marknader för gynnade hud färger4. Studier av hypopigmentering och anti-melanogenic aktivitet är därför viktiga både vetenskapligt och praktiskt.
Melanogenes är den komplexa processen att melanin biosyntes genom en serie enzymatiska och spontana kemiska reaktioner i melanocyterna. En melanocyte omges av cirka 36 keratinocyter och melanocyter är de fabriker av melanin-syntesen som distribuerar sin produkt till närliggande keratinocyter. I huden transporteras melanin produceras och lagras i melanosomal facket av melanocyter till närliggande keratinocyter i epidermis via dendriter.
L-tyrosin serverar ursprungliga substratet för melanogenes och enzymet tyrosinase katalyserar två på varandra följande reaktioner att omvandla L-tyrosin i 3,4-dihydroxifenylalanin (DOPA) och sedan in i dopaquinone. Dessa reaktioner är det hastighetsbegränsande steget i melanogenes5,6. Hypopigmentering aktivitet kan följaktligen först mätas genom att bedöma cellulära tyrosinase aktivitet direkt. Till gör så, melanocyte extrakt som innehåller tyrosinas inkuberas med DOPA och den dopaquinone som produceras i proverna kan mätas genom spektrofotometri på 475 nm. Värdena är normaliserade av protein koncentrationerna av prover och ämnen med hypopigmentering aktivitet resulterar i mindre dopaquinone bildning jämfört med kontroller.
För det andra, hypopigmentering aktivitet kan kvantifieras genom mätning melanin i odlade melanocyter direkt. Efter behandling av celler med testämnet, melanin utvinns under alkaliska förhållanden och melanin innehållet kvantifieras i spektrofotometri vid 400 nm. En hypopigmentering agent kommer att resultera i en lägre melanin-halt än kontroller7.
Slutligen kan aktiviteten hypopigmentering kvantifieras av Fontana-Masson melanin färgning och efterföljande bildanalys. I Fontana-Masson färgning, melanin granulat minska ammoniak-silvernitrat till en synlig svart metalliskt tillstånd och svarta områden av celler i mikroskopiska bilder representerar mängden melanin.
En hypopigmentering agent ger oftast konsekventa och jämförbara resultat med dessa tre metoder, vilket bekräftar att aktiviteten som substansen är giltig. Alternativt kan det vara bra att mäta uttrycket av viktiga gener och proteiner i melanogenes som svar på en testsubstans att undersöka hypopigmentering aktivitet. Utöver tyrosinase är tyrosinas-relaterade proteiner (TRP-1) och dopachrome tautomerase (TRP-2) kritiska enzymer i melanogenes8. De transkription faktorn mikroftalmi-associerade transkriptionsfaktor (MITF) är en mästare regulator i melanogenes och kvantifiering av dess gen/proteinnivåer med uttryck eller en arrangören aktivitet assay kan också användas för att bedöma hypopigmentering aktivitet.

<table>
	<tbody>
		<tr>
			<td>3,4-Dihydroxy-l-phenylalanine</td>
			<td>Sigma</td>
			<td>D9628</td>
			<td></td>
		</tr>
		<tr>
			<td>Ammonium hydroxide solution</td>
			<td>Sigma</td>
			<td>#320145</td>
			<td></td>
		</tr>
		<tr>
			<td>Arbutin</td>
			<td>Fluka</td>
			<td>#10960</td>
			<td></td>
		</tr>
		<tr>
			<td>DMEM</td>
			<td>HyClone</td>
			<td>SH30243.01</td>
			<td></td>
		</tr>
		<tr>
			<td>FBS</td>
			<td>HyClone</td>
			<td>SH30084.03</td>
			<td></td>
		</tr>
		<tr>
			<td>Formalin</td>
			<td>Yakuri Pure Chemicals</td>
			<td>#16223</td>
			<td>37%</td>
		</tr>
		<tr>
			<td>Gold chloride</td>
			<td>American MasterTech</td>
			<td>AHG0226</td>
			<td>0.10%</td>
		</tr>
		<tr>
			<td>HCl</td>
			<td>Samchun chemical</td>
			<td>H0255</td>
			<td></td>
		</tr>
		<tr>
			<td>KCl</td>
			<td>Bio basic Canada Inc.</td>
			<td>PB0440</td>
			<td></td>
		</tr>
		<tr>
			<td>KH2PO4</td>
			<td>Sigma</td>
			<td>#60218</td>
			<td></td>
		</tr>
		<tr>
			<td>Na2HPO4</td>
			<td>J.T.Baker</td>
			<td>#3817-01</td>
			<td></td>
		</tr>
		<tr>
			<td>NaCl</td>
			<td>Duksan pure chemicals</td>
			<td>#81</td>
			<td></td>
		</tr>
		<tr>
			<td>NaOH</td>
			<td>Sigma</td>
			<td>655104</td>
			<td></td>
		</tr>
		<tr>
			<td>Nuclear fast red</td>
			<td>Merck</td>
			<td>100121</td>
			<td>Nuclear fast red 0.1% in 5% aluminum sulfate.</td>
		</tr>
		<tr>
			<td>Penicillin and streptomycin solution</td>
			<td>HyClone</td>
			<td>SV30010</td>
			<td></td>
		</tr>
		<tr>
			<td>Silver nitrate</td>
			<td>Duksan Pure Chemicals</td>
			<td>#900</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium phosphate dibasic (Na2HPO4)</td>
			<td>J.T. Baker</td>
			<td>#3817-01</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium phosphate monobasic (Na2HPO4)</td>
			<td>Sigma</td>
			<td>S5011</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium thiosulfate pentahydrate</td>
			<td>Duksan Pure Chemicals</td>
			<td>#2163</td>
			<td></td>
		</tr>
		<tr>
			<td>Tris(hydroxymethyl)aminomethane</td>
			<td>Bio Basic Canada</td>
			<td>TB0196</td>
			<td></td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>Union Carbide</td>
			<td>T8787</td>
			<td></td>
		</tr>
		<tr>
			<td>Tyrosinase from mushroom</td>
			<td>Sigma</td>
			<td>T3824</td>
			<td>25 KU</td>
		</tr>
	</tbody>
</table>

quantification of hypopigmentation activity in vitro

Denna studie presenterar laborativa metoder för kvantifiering av hypopigmentering aktivitet in vitro. Melanin, stora pigmentet i melanocyterna, syntetiseras som svar på flera cellulära och miljömässiga faktorer. Melanin skyddar hudcellerna från ultraviolett skador, men har också biofysiska och biokemiska funktioner. Överdriven produktion eller ackumulering av melanin i melanocyter kan orsaka dermatologiska problem, såsom fräknar, pigmentfläckar, melasma och mullvadar. Kontroll av melanogenes med hypopigmentering agenter är därför viktigt hos individer med kliniska eller kosmetiska behov. Melanin bildas främst i melanosomer av melanocyterna i en komplicerad biokemisk process som kallas melanogenes, som påverkas av extrinsic och inneboende faktorer, såsom hormoner, inflammation, ålder och ultraviolett ljus exponering. Vi beskriver tre metoder för att bestämma aktiviteten hypopigmentering av kemikalier eller naturliga ämnen i melanocyterna: mätning av 1) cellulär tyrosinase aktivitet och 2) melanin innehåll och 3) färgning och kvantifiera cellulära melanin med bild analys.
I melanogenes katalyserar tyrosinas det hastighetsbegränsande steget som konverterar L-tyrosin i 3,4-dihydroxifenylalanin (L-DOPA) och sedan till dopaquinone. Hämning av tyrosinas är därför en primär hypopigmentering mekanism. I odlade melanocyter, kan tyrosinase aktivitet kvantifieras genom att lägga till L-DOPA som substrat och mäta dopaquinone produktion av spektrofotometri. Melanogenes kan även mätas genom kvantifiering av melanin-halt. Andelen som innehåller melanin cellulära extraheras med NaOH och melanin är kvantifierade spektrofotometriskt. Slutligen kan den melanin-halten kvantifieras av bildanalys efter Fontana-Masson färgning av melanin. Även om resultaten av dessa in vitro-testmetoder inte får alltid återges i mänsklig hud, används dessa metoder allmänt i melanogenes forskning, särskilt som det första steget att identifiera potentiella hypopigmentering aktivitet. Dessa metoder kan också användas för att bedöma melanocyte aktivitet, tillväxt och differentiering. Konsekventa resultat med de tre olika metoderna försäkrar om validiteten på effekterna.

Representativa resultat för aktiviteten hypopigmentering av arbutin, en anti-melanogenic förening, i B16F10 melanocyter visas nedan. Figur 1A visar det arbutin signifikant suppression av cellulära tyrosinase aktiviteten jämfört med kontrollen behandlade. Likaså minskade den melanin-halten i celler stimuleras med arbutin signifikant jämfört med kontroller (figur 1B). Mikroskopiska bilder av celler som färgas med Fontana-M...

Watch this Scientific Journal Video about Quantification of Hypopigmentation Activity In Vitro at JoVE.com

Quantification of Hypopigmentation Activity In Vitro

Vi beskriver tre experimentella metoder för att utvärdera aktiviteten hypopigmentering av kemikalier in vitro-: kvantifiering av 1) cellulär tyrosinase aktivitet och 2) melanin innehåll och (3) mätning av melanin genom cellulär melanin färgning och bild analys.

Kvantifiering av hypopigmentering aktivitet In Vitro

This study presents laboratory methods for the quantification of hypopigmentation activity in vitro. Melanin, the major pigment in melanocytes, is ...

Denna metod kan vara till hjälp i utvecklingen av funktionell kosmetika och hud agent med anti-melanogenic verksamhet. Det är där för att utföra och resultatet kan erhållas snabbt. Dessutom kan denna metod vara användbar för forskare, som vill identifiera eller undersöka effekterna eller föreningarna eller undersöka de antimelanogenic eller promelanogenic aktiviteter.Att mäta till Tyrosinas aktivitet börja genom sådd B16-F10 Melanicides på en fem gånger 10 till den fjärde celler per brunn av en 24 väl plåt koncentration i komplett medium i 24 timmar i en cellkultur inkubator. Nästa dag, byt ut supernatanten i varje brunn med DMEM kompletterat med nyberedda testförening och inhibitorkontroll eller en negativ kontroll och återsända plattan till inkubatorn i ytterligare 72 timmar. I slutet av behandlingen skölj brunnarna två gånger med 300 mikroliter av kall pbs per brunn och placera plattan på is.Nästa lägga till 300 mikroliter av lysbuffert till varje brunn med hjälp av en cell skrapa för att samla cellen lysates efter fem minuter. Överför de resulterande cellpartikelupphängningar till enskilda 1,5 milliliter mikro-centrifugrör. Och homogenisera lysaterna tre gånger i två sekunder vid 14, 500 rpm på is för att frigöra den intercellulära Tyrosinasen.Pellet cellskräpet genom centrifugering och överför supernatanterna till enskilda 1,5 milliliter centrifugrör på is. Fördela 70 mikroliter av varje supernatant till enskilda brunnar av en klar 96 väl polystyren mikroplatta och tillsätt 140 mikroliter av Tyrosinase substratlösning till varje brunn av supernatant. Skakar plattan skonsamt för att blanda brunnsinnehållet.Sedan inkubera plattan vid 37 grader varmt i två timmar. Och mäta till Tyrosinas aktivitet vid 475 nanometer på en mikroplatt läsare. Att mäta melaninhalten i cellerna efter att ha samlat lysate av de behandlade cellerna som visat.Samla ihop lysaterna genom centrifugering och för över supernatanterna till nya rör. Tillsätt 300 mikroliter av en normal natriumhydroxid till varje pellet för en timmes inkubation vid 60 grader Celsius. Följt av centrifugeringen av de upplösta cellupphängningar.Överför sedan 200 mikroliter av supernatanterna till varje brunn av en 96 brunnsplatta. Och mäta melanin innehållet på en mikroplatt läsare på en 400 nanometer våglängd. För Fontana-Masson Färgning, tvätta de behandlade cellerna två gånger med 300 mikroliter av kall pbs och fixa cellerna med 200 mikroliter av 10%formalin i en timme vid fyra grader Celsius.Skölj de tjocka cellerna med destillerat vatten och tillsätt 200 mikroliter på 58 till 68 grader celsius Ammoniak silver arbetslösning till varje brunn. För en timmes inkubation vid 37 grader Celsius eller tills cellerna blir gulbruna i färg. Skölj de färgade cellerna med destillerat vatten följt av två minuters inkubation i 0,1%guldklorid vid rumstemperatur.Skölj de guldkloridbehandlade cellerna med destillerat vatten och tillsätt 200 mikroliter av natriumtiosulfatlösning till cellerna. Efter två minuter skölj cellerna igen. Och märka cellerna med 200 mikroliter av nukleära snabbt rött per brunn i fem minuter.Tvätta sedan de färgade cellerna med kranvatten före avbildning under ett ljusmikroskop. För tröskelanalys öppnar du bilderna i bild J och väljer bild, justera och Färgtröskel. Att mäta området färgas med Fontana Masson ställa in ljusstyrka parametern bar till noll och justera ljusstyrkan till den punkt där alla de svarta eller bruna färgade cellerna ingår.Välj Analysera och analysera partiklar och markera summarize rutan i analysera partiklar fönstret klicka sedan på okej för att få en sammanfattning av resultaten och kopiera och klistra in data i ett kalkylblad. Arbutin behandling dämpar signifikant cellulär Tyrosinas aktivitet jämfört med kontroll fordonet behandlade celler. Likaså melanin innehållet av celler stimuleras med Arbutin minskas avsevärt jämfört med kontrollerna.Även om cellerna är morfologiskt lika mellan behandlingsgrupper, minskar Arbutin området av svart pigment jämfört med den kontroll behandlade celler. Denna metod är användbara för aktiviteter screening med hjälp av vår sammansatta bibliotek. Det finns över hundratals prover som ska testas snabbt.Dessutom denna metod kan också användas för att undersöka mekanismen som involverar melanogenesis. Efter de bioaktiva kandidaterna föreningar har identifierats, för deras vittnesmål till studiet av biologiska mekanismer eller kommersiella tillämpningar.

quantification-of-hypopigmentation-activity-in-vitro

Research

JoVE Journal

Biochemistry

Detection of the pH-dependent Activity of Escherichia coli Chaperone HdeB In Vitro and In Vivo

Bacteria are frequently exposed to environmental changes, such as alterations in pH, temperature, redox status, light exposure or mechanical force. Many of these conditions cause protein unfolding in the cell and have detrimental impact on the survival of the organism. A group of unrelated, stress-specific molecular chaperones have been shown to play essential roles in the survival of these stress conditions. While fully folded and chaperone-inactive before stress, these proteins rapidly unfold and become chaperone-active under specific stress conditions. Once activated, these conditionally disordered chaperones bind to a large number of different aggregation-prone proteins, prevent their aggregation and either directly or indirectly facilitate protein refolding upon return to non-stress conditions. The primary approach for gaining a more detailed understanding about the mechanism of their activation and client recognition involves the purification and subsequent characterization of these proteins using in vitro chaperone assays. Follow-up in vivo stress assays are absolutely essential to independently confirm the obtained in vitro results.
This protocol describes in vitro and in vivo methods to characterize the chaperone activity of E. coli HdeB, an acid-activated chaperone. Light scattering measurements were used as a convenient read-out for HdeB&#39;s capacity to prevent acid-induced aggregation of an established model client protein, MDH, in vitro. Analytical ultracentrifugation experiments were applied to reveal complex formation between HdeB and its client protein LDH, to shed light into the fate of client proteins upon their return to non-stress conditions. Enzymatic activity assays of the client proteins were conducted to monitor the effects of HdeB on pH-induced client inactivation and reactivation. Finally, survival studies were used to monitor the influence of HdeB&#39;s chaperone function in vivo.

Detection of the pH-dependent Activity of Escherichia coli Chaperone HdeB In Vitro and In Vivo

This study describes biophysical, biochemical and molecular techniques to characterize the chaperone activity of Escherichia coli HdeB under acidic pH conditions. These methods have been successfully applied for other acid-protective chaperones such as HdeA and can be modified to work for other chaperones and stress conditions.

Detektering av den pH-beroende aktivitet för<em&gt; Escherichia coli</em&gt; Chaperone HdeB<em&gt; In Vitro</em&gt; och<em&gt; In Vivo</em

Bacteria are frequently exposed to environmental changes, such as alterations in pH, temperature, redox status, light exposure or mechanical force. Many ...

Quantification of the Abundance and Charging Levels of Transfer RNAs in Escherichia coli

Transfer RNA (tRNA) is an essential part of the translational machinery in any organism. tRNAs bind and transfer amino acids to the translating ribosome. The relative levels of different tRNAs, and the ratio of aminoacylated tRNA to total tRNA, known as the charging level, are important factors in determining the accuracy and speed of translation. Therefore, the abundance and charging levels of tRNAs are important variables to measure when studying protein synthesis, for example under various stress conditions. Here, we describe a method for harvesting tRNA and directly measuring both the relative abundance and the absolute charging level of specific tRNA species in Escherichia coli. The tRNA is harvested in such a way that the labile bond between the tRNA and its amino acid is preserved. The RNA is then subjected to gel electrophoresis and Northern blotting, which results in separation of the charged and uncharged tRNAs. The levels of specific tRNAs in different samples can be compared due to the addition of spike-in cells for normalization. Prior to RNA purification, we add 5% of E. coli cells that overproduce the rare tRNAselC to each sample. The amount of the tRNA species of interest in a sample is then normalized to the amount of tRNAselC in the same sample. Addition of spike-in cells prior to RNA purification has the advantage over addition of purified spike-in RNAs that it also accounts for any differences in cell lysis efficiency between samples.

Quantification of the Abundance and Charging Levels of Transfer RNAs in Escherichia coli

Here we present a method for directly measuring transfer RNA charging levels from purified Escherichia coli RNA as well as a way to compare relative levels of transfer RNA, or any other short RNA, across different samples based on the addition of spike-in cells expressing a reference gene.

Kvantifiering av överflödet och laddning nivåer av överföring RNAs i Escherichia coli

Transfer RNA (tRNA) is an essential part of the translational machinery in any organism. tRNAs bind and transfer amino acids to the translating ribosome. ...

Mapping Metabolism: Monitoring Lactate Dehydrogenase Activity Directly in Tissue

Mapping enzymatic activity in space and time is critical for understanding the molecular basis of cell behavior in normal tissue and disease. In situ metabolic activity assays can provide information about the spatial distribution of metabolic activity within a tissue. We provide here a detailed protocol for monitoring the activity of the enzyme lactate dehydrogenase directly in tissue samples. Lactate dehydrogenase is an important determinant of whether consumed glucose will be converted to energy via aerobic or anaerobic glycolysis. A solution containing lactate and NAD is provided to a frozen tissue section. Cells with high lactate dehydrogenase activity will convert the provided lactate to pyruvate, while simultaneously converting provided nicotinamide adenine dinucleotide (NAD) to NADH and a proton, which can be detected based on the reduction of nitrotetrazolium blue to formazan, which is visualized as a blue precipitate. We describe a detailed protocol for monitoring lactate dehydrogenase activity in mouse skin. Applying this protocol, we found that lactate dehydrogenase activity is high in the quiescent hair follicle stem cells within the skin. Applying the protocol to cultured mouse embryonic stem cells revealed higher staining in cultured embryonic stem cells than mouse embryonic fibroblasts. Analysis of freshly isolated mouse aorta revealed staining in smooth muscle cells perpendicular to the aorta. The methodology provided can be used to spatially map the activity of enzymes that generate a proton in frozen or fresh tissue.

We describe a protocol for mapping the spatial distribution of enzymatic activity for enzymes that generate nicotinatmide adenine dinucleotide phosphate (NAD(P)H) + H+ directly in tissue samples.

Kartläggning Metabolism: Övervakning av laktatdehydrogenas aktivitet direkt i vävnad

Mapping enzymatic activity in space and time is critical for understanding the molecular basis of cell behavior in normal tissue and disease. In situ ...

An In Vitro Assay to Detect tRNA-Isopentenyl Transferase Activity

N6-isopentenyladenosine RNA modifications are functionally diverse and highly conserved among prokaryotes and eukaryotes. One of the most highly conserved N6-isopentenyladenosine modifications occurs at the A37 position in a subset of tRNAs. This modification improves translation efficiency and fidelity by increasing the affinity of the tRNA for the ribosome. Mutation of enzymes responsible for this modification in eukaryotes are associated with several disease states, including mitochondrial dysfunction and cancer. Therefore, understanding the substrate specificity and biochemical activities of these enzymes is important for understanding of normal and pathologic eukaryotic biology. A diverse array of methods has been employed to characterize i6A modifications. Herein is described a direct approach for the detection of isopentenylation by Mod5. This method utilizes incubation of RNAs with a recombinant isopentenyl transferase, followed by RNase T1 digestion, and 1-dimensional gel electrophoresis analysis to detect i6A modifications. In addition, the potential adaptability of this protocol to characterize other RNA-modifying enzymes is discussed.

An In Vitro Assay to Detect tRNA-Isopentenyl Transferase Activity

Here, we describe a protocol for the biochemical characterization of the yeast RNA-modifying enzyme, Mod5, and discuss how this protocol could be applied to other RNA-modifying enzymes.

En In Vitro Assay att upptäcka tRNA-Isopentenyl transferas aktivitet

N6-isopentenyladenosine RNA modifications are functionally diverse and highly conserved among prokaryotes and eukaryotes. One of the most highly conserved ...

Calibration-free In Vitro Quantification of Protein Homo-oligomerization Using Commercial Instrumentation and Free, Open Source Brightness Analysis Software

Number and brightness is a calibration-free fluorescence fluctuation spectroscopy (FFS) technique for detecting protein homo-oligomerization. It can be employed using a conventional confocal microscope equipped with digital detectors. A protocol for the use of the technique in vitro is shown by means of a use case where number and brightness can be seen to accurately quantify the oligomeric state of mVenus-labelled FKBP12F36V before and after the addition of the dimerizing drug AP20187. The importance of using the correct microscope acquisition parameters and the correct data preprocessing and analysis methods are discussed. In particular, the importance of the choice of photobleaching correction is stressed. This inexpensive method can be employed to study protein-protein interactions in many biological contexts.

Calibration-free In Vitro Quantification of Protein Homo-oligomerization Using Commercial Instrumentation and Free, Open Source Brightness Analysis Software

This protocol describes a calibration-free approach for quantifying protein homo-oligomerization in vitro based on fluorescence fluctuation spectroscopy using commercial light scanning microscopy. The correct acquisition settings and analysis methods are shown.

Kalibrering-gratis In Vitro kvantifiering av Protein Homo-oligomerisering använder kommersiella instrumentering och fri, öppen källkod ljusstyrka analys programvara

Number and brightness is a calibration-free fluorescence fluctuation spectroscopy (FFS) technique for detecting protein homo-oligomerization. It can be ...

A Colorimetric Assay of Citrate Synthase Activity in Drosophila Melanogaster

Mitochondria play the most prominent roles in cellular metabolism by producing ATP through oxidative phosphorylation and regulating a variety of physiological processes. Mitochondrial dysfunction is a primary cause of a number of metabolic and neurodegenerative diseases. Intact mitochondria are critical for their proper functioning. The enzyme citrate synthase is localized in the mitochondrial matrix and thus can be used as a quantitative enzyme marker of intact mitochondrial mass. Given that many molecules and pathways that have important functions in mitochondria are highly conserved between humans and Drosophila, and that an array of powerful genetic tools are available in Drosophila, Drosophila serves as a good model system for studying mitochondrial function. Here, we present a protocol for fast and simple measurement of citrate synthase activity in tissue homogenate from adult flies without isolating mitochondria. This protocol is also suitable for measuring citrate synthase activity in larvae, cultured cells, and mammalian tissues.

A Colorimetric Assay of Citrate Synthase Activity in Drosophila Melanogaster

We present a protocol for a colorimetric assay of citrate synthase activity for quantification of intact mitochondrial mass in Drosophila tissue homogenates.

En kolorimetrisk analys av Citratsyntas aktivitet i Drosophila melanogaster

Mitochondria play the most prominent roles in cellular metabolism by producing ATP through oxidative phosphorylation and regulating a variety of ...

Synthesis of a Deuterated Standard for the Quantification of 2-Arachidonoylglycerol in Caenorhabditis elegans

This work presents a method to prepare an analytical standard to analyze 2-arachidonoyl glycerol (2-AG) qualitatively and quantitatively by liquid chromatography-electrospray Ionization-tandem mass spectrometry (LC-ESI-MS/MS). Endocannabinoids are conserved lipid mediators that regulate multiple biological processes in a variety of organisms. In C. elegans, 2-AG has been found to possess different roles, including modulation of dauer formation and cholesterol metabolism. This report describes a method to overcome the difficulties associated with the costs and stability of deuterated standards required for 2-AG quantification. The procedure for the synthesis of the standard is simple and can be performed in any laboratory, without the need for organic synthesis expertise or special equipment. In addition, a modification of Folch&#39;s method to extract the deuterated standard from C. elegans culture is described. Finally, a quantitative and analytic method to detect 2-AG using the stable isotopically labeled analog 1-AG-d5 is described, which provides reliable results in a fast-chromatographic run. The procedure is useful for studying the multiple roles of 2-AG in C. elegans while also being applicable to other studies of metabolites in different organisms.

Synthesis of a Deuterated Standard for the Quantification of 2-Arachidonoylglycerol in Caenorhabditis elegans

This work describes a robust and straightforward method to detect and quantify the endocannabinoid 2-arachidonoylglycerol (2-AG) in C. elegans. An analytical deuterated standard us prepared and used for the quantification of 2-AG by isotopic dilution and liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS).

Syntes av en Deuterat standard för kvantifiering av 2-Arachidonoylglycerol i Caenorhabditis elegans

This work presents a method to prepare an analytical standard to analyze 2-arachidonoyl glycerol (2-AG) qualitatively and quantitatively by liquid ...

Quantification of Protein Interaction Network Dynamics using Multiplexed Co-Immunoprecipitation

Dynamic protein-protein interactions control cellular behavior, from motility to DNA replication to signal transduction. However, monitoring dynamic interactions among multiple proteins in a protein interaction network is technically difficult. Here, we present a protocol for Quantitative Multiplex Immunoprecipitation (QMI), which allows quantitative assessment of fold changes in protein interactions based on relative fluorescence measurements of Proteins in Shared Complexes detected by Exposed Surface epitopes (PiSCES). In QMI, protein complexes from cell lysates are immunoprecipitated onto microspheres, and then probed with a labeled antibody for a different protein in order to quantify the abundance of PiSCES. Immunoprecipitation antibodies are conjugated to different MagBead spectral regions, which allows a flow cytometer to differentiate multiple parallel immunoprecipitations and simultaneously quantify the amount of probe antibody associated with each. QMI does not require genetic tagging and can be performed using minimal biomaterial compared to other immunoprecipitation methods. QMI can be adapted for any defined group of interacting proteins, and has thus far been used to characterize signaling networks in T cells and neuronal glutamate synapses. Results have led to new hypothesis generation with potential diagnostic and therapeutic applications. This protocol includes instructions to perform QMI, from the initial antibody panel selection through to running assays and analyzing data. The initial assembly of a QMI assay involves screening antibodies to generate a panel, and empirically determining an appropriate lysis buffer. The subsequent reagent preparation includes covalently coupling immunoprecipitation antibodies to MagBeads, and biotinylating probe antibodies so they can be labeled by a streptavidin-conjugated fluorophore. To run the assay, lysate is mixed with MagBeads overnight, and then beads are divided and incubated with different probe antibodies, and then a fluorophore label, and read by flow cytometry. Two statistical tests are performed to identify PiSCES that differ significantly between experimental conditions, and results are visualized using heatmaps or node-edge diagrams.

Quantitative Multiplex Immunoprecipitation (QMI) uses flow cytometry for sensitive detection of differences in the abundance of targeted protein-protein interactions between two samples. QMI can be performed using a small amount of biomaterial, does not require genetically engineered tags, and can be adapted for any previously defined protein interaction network.

Kvantifiering av proteininteraktion Nätverksdynamik med hjälp av multiplexerade Co-immunoprecipitation

Dynamic protein-protein interactions control cellular behavior, from motility to DNA replication to signal transduction. However, monitoring dynamic ...

Quantification of Coenzyme A in Cells and Tissues

Emerging research has revealed that the cellular coenzyme A (CoA) supply can become limiting with a detrimental impact on growth, metabolism and survival. Measurement of cellular CoA is a challenge due to its relatively low abundance and the dynamic conversion of free CoA to CoA thioesters that, in turn, participate in numerous metabolic reactions. A method is described that navigates through potential pitfalls during sample preparation to yield an assay with a broad linear range of detection that is suitable for use in many biomedical laboratories.

This method describes sample preparation from cultured cells and animal tissues, extraction and derivatization of coenzyme A in the samples, followed by high pressure liquid chromatography for purification and quantification of the derivatized coenzyme A by absorbance or fluorescence detection.

Kvantifiering av coenzym A i celler och vävnader

Emerging research has revealed that the cellular coenzyme A (CoA) supply can become limiting with a detrimental impact on growth, metabolism and survival. ...

Storskalig kvantifiering av syntes och distribution av mtDNA

High-Throughput Image-Based Quantification of Mitochondrial DNA Synthesis and Distribution

The vast majority of cellular processes require a continuous supply of energy, the most common carrier of which is the ATP molecule. Eukaryotic cells produce most of their ATP in the mitochondria by oxidative phosphorylation. Mitochondria are unique organelles because they have their own genome that is replicated and passed on to the next generation of cells. In contrast to the nuclear genome, there are multiple copies of the mitochondrial genome in the cell. The detailed study of the mechanisms responsible for the replication, repair, and maintenance of the mitochondrial genome is essential for understanding the proper functioning of mitochondria and whole cells under both normal and disease conditions. Here, a method that allows the high-throughput quantification of the synthesis and distribution of mitochondrial DNA (mtDNA) in human cells cultured in vitro is presented. This approach is based on the immunofluorescence detection of actively synthesized DNA molecules labeled by 5-bromo-2'-deoxyuridine (BrdU) incorporation and the concurrent detection of all the mtDNA molecules with anti-DNA antibodies. Additionally, the mitochondria are visualized with specific dyes or antibodies. The culturing of cells in a multi-well format and the utilization of an automated fluorescence microscope make it easier to study the dynamics of mtDNA and the morphology of mitochondria under a variety of experimental conditions in a relatively short time.

Författare i fokus: Bildbaserad kvantifiering av mitokondriell DNA-syntes och distribution med hög genomströmning  

A procedure for studying the dynamics of mitochondrial DNA (mtDNA) metabolism in cells using a multi-well plate format and automated immunofluorescence imaging to detect and quantify mtDNA synthesis and distribution is described. This can be further used to investigate the effects of various inhibitors, cellular stresses, and gene silencing on mtDNA metabolism.

Bildbaserad kvantifiering av mitokondriell DNA-syntes och distribution med hög kapacitet

The vast majority of cellular processes require a continuous supply of energy, the most common carrier of which is the ATP molecule. Eukaryotic cells ...