Name: functional characterization of carboxylesterases in insecticide resistant house flies, musca domestica
Uploaded: 2018-08-23T14:30:00
Description: Watch this Scientific Journal Video about Functional Characterization of Carboxylesterases in Insecticide Resistant House Flies, Musca Domestica at JoVE.com

1. uttryck och isolering av målproteiner med en baculoviridae-medierad insekt Cell uttryck systemet
<ol><li>Directionally klona blunt-slutade PCR-produkter av målproteiner från hus flugor.<ol>
<li>Design PCR primers av grönt fluorescerande protein (GFP) och huset flyga MdαE7 genen baserat på deras sekvenser och de särskilda kraven för den valda vektorn (tabell 1).</li>
		<li>Använd en termostabila, korrekturläsning DNA-polymeras och primers från steg 1.1.1 för att utföra en 150 µL PCR-rea...

<ol>
	<li>Scott, J. G., 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=Insecticide+resistance+in+house+flies+from+the+United+States:+Resistance+levels+and+frequency+of+pyrethroid+resistance+alleles.">Insecticide resistance in house flies from the United States: Resistance levels and frequency of pyrethroid resistance alleles.</a> Pesticide Biochemistry and Physiology. 107 (3), 377-384 (2013).</li><li>Li, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+whole+transcriptomal+linkage+analysis+of+gene+co-regulation+in+insecticide+resistant+house+flies,+Musca+domestica.">A whole transcriptomal linkage analysis of gene co-regulation in insecticide resistant house flies, Musca domestica.</a> BMC Genomics. 14, 803 (2013).</li><li>Liu, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Insecticide+resistance+in+mosquitoes:+impact,+mechanisms,+and+research+directions.">Insecticide resistance in mosquitoes: impact, mechanisms, and research directions.</a> Annual Review of Entomology. 60, 537-559 (2015).</li><li>Grigoraki, 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=Transcriptome+profiling+and+genetic+study+reveal+amplified+carboxylesterase+genes+implicated+in+temephos+resistance,+in+the+Asian+tiger+mosquito+Aedes+albopictus.">Transcriptome profiling and genetic study reveal amplified carboxylesterase genes implicated in temephos resistance, in the Asian tiger mosquito Aedes albopictus.</a> e0003771. 9, e0003771 (2015).</li><li>Grigoraki, 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=Carboxylesterase+gene+amplifications+associated+with+insecticide+resistance+in+Aedes+albopictus:+Geographical+distribution+and+evolutionary+origin.">Carboxylesterase gene amplifications associated with insecticide resistance in Aedes albopictus: Geographical distribution and evolutionary origin.</a> PLOS Neglected Tropical Diseases. 11, e0005533 (2017).</li><li>Wheelock, C., Shan, G., Ottea, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Overview+of+carboxylesterases+and+their+role+in+the+metabolism+of+insecticides.">Overview of carboxylesterases and their role in the metabolism of insecticides.</a> Journal of Pesticide Science. 30, 75-83 (2005).</li><li>Feng, X., Li, M., Liu, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Carboxylesterase+genes+in+pyrethroid+resistant+house+flies,+Musca+domestica.">Carboxylesterase genes in pyrethroid resistant house flies, Musca domestica.</a> Insect Biochemistry and Molecular Biology. 92, 30-39 (2018).</li><li>Mosmann, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+colorimetric+assay+for+cellular+growth+and+survival:+application+to+proliferation+and+cytotoxicity+assays.">Rapid colorimetric assay for cellular growth and survival: application to proliferation and cytotoxicity assays.</a> J Immunol Methods. 65 (1-2), 55-63 (1983).</li><li>Jarvis, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Baculovirus-insect+cell+expression+systems.">Baculovirus-insect cell expression systems.</a> Methods in Enzymology. 463, 191-222 (2009).</li><li>Berger, I., Fitzgerald, D. J., Richmond, T. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Baculovirus+expression+system+for+heterologous+multiprotein+complexes.">Baculovirus expression system for heterologous multiprotein complexes.</a> Nature Biotechnology. 22 (12), 1583 (2004).</li><li>Gong, Y., Li, T., Feng, Y., Liu, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+function+of+two+P450s,+CYP9M10+and+CYP6AA7,+in+the+permethrin+resistance+of+Culex+quinquefasciatus.">The function of two P450s, CYP9M10 and CYP6AA7, in the permethrin resistance of Culex quinquefasciatus.</a> Scientific Reports. 7 (1), 587 (2017).</li><li>Cao, C. W., Zhang, J., Gao, X. W., Liang, P., Guo, H. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Overexpression+of+carboxylesterase+gene+associated+with+organophosphorous+insecticide+resistance+in+cotton+aphids,+Aphis+gossypii+(Glover).">Overexpression of carboxylesterase gene associated with organophosphorous insecticide resistance in cotton aphids, Aphis gossypii (Glover).</a> Pesticide Biochemistry and Physiology. 90 (3), 175-180 (2008).</li><li>Zhang, L., Gao, X., Liang, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Beta-cypermethrin+resistance+associated+with+high+carboxylesterase+activities+in+a+strain+of+house+fly,+Musca+domestica+(Diptera:+Muscidae).">Beta-cypermethrin resistance associated with high carboxylesterase activities in a strain of house fly, Musca domestica (Diptera: Muscidae).</a> Pesticide Biochemistry and Physiology. 89, 65-72 (2007).</li><li>Van Meerloo, J., Kaspers, G. J., Cloos, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+sensitivity+assays:+the+MTT+assay.">Cell sensitivity assays: the MTT assay.</a> Cancer cell culture. , 237-245 (2011).</li><li>Stockert, J. C., Bl&#225;zquez-Castro, A., Ca&#241;ete, M., Horobin, R. W., Villanueva, &. #. 1. 9. 3. ;. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MTT+assay+for+cell+viability:+Intracellular+localization+of+the+formazan+product+is+in+lipid+droplets.">MTT assay for cell viability: Intracellular localization of the formazan product is in lipid droplets.</a> Acta Histochemica. 114 (8), 785-796 (2012).</li><li>Strober, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Trypan+blue+exclusion+test+of+cell+viability.">Trypan blue exclusion test of cell viability.</a> Current Protocols in Immunology. , (2001).</li><li>Riss, T. L., Moravec, R. A., Niles, A. L., Duellman, S., Benink, H. A., Worzella, T. J., Minor, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+viability+assays.">Cell viability assays.</a> Assay Guidance Manual. , (2013).</li><li>Wheelock, C. E., Shan, G., Ottea, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Overview+of+carboxylesterases+and+their+role+in+the+metabolism+of+insecticides.">Overview of carboxylesterases and their role in the metabolism of insecticides.</a> Journal of Pesticide Science. 30 (2), 75-83 (2005).</li><li>Li, X., Schuler, M. A., Berenbaum, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+mechanisms+of+metabolic+resistance+to+synthetic+and+natural+xenobiotics.">Molecular mechanisms of metabolic resistance to synthetic and natural xenobiotics.</a> Annual Review of Entomology. 52, 231-253 (2007).</li><li>Nakamura, 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=The+in+vitro+metabolism+of+a+pyrethroid+insecticide,+permethrin,+and+its+hydrolysis+products+in+rats.">The in vitro metabolism of a pyrethroid insecticide, permethrin, and its hydrolysis products in rats.</a> Toxicology. 235 (3), 176-184 (2007).</li><li>Kruger, N. 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+Bradford+method+for+protein+quantitation.">The Bradford method for protein quantitation.</a> The protein protocols handbook. , 15-21 (2002).</li><li>Macauley-Patrick, S., Fazenda, M. L., McNeil, B., Harvey, L. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heterologous+protein+production+using+the+Pichia+pastoris+expression+system.">Heterologous protein production using the Pichia pastoris expression system.</a> Yeast. 22 (4), 249-270 (2005).</li><li>Berger, I., Fitzgerald, D. J., Richmond, T. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Baculovirus+expression+system+for+heterologous+multiprotein+complexes.">Baculovirus expression system for heterologous multiprotein complexes.</a> Nature Biotechnology. 22 (12), 1583 (2004).</li><li>Terpe, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Overview+of+bacterial+expression+systems+for+heterologous+protein+production:+from+molecular+and+biochemical+fundamentals+to+commercial+systems.">Overview of bacterial expression systems for heterologous protein production: from molecular and biochemical fundamentals to commercial systems.</a> Applied Microbiology and Biotechnology. 72 (2), 211 (2006).</li><li>Bulter, T., 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=Functional+expression+of+a+fungal+laccase+in+Saccharomyces+cerevisiae+by+directed+evolution.">Functional expression of a fungal laccase in Saccharomyces cerevisiae by directed evolution.</a> Applied Microbiology and Biotechnology. 69 (2), 987-995 (2003).</li><li>Stepanenko, A. A., Dmitrenko, V. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pitfalls+of+the+MTT+assay:+Direct+and+off-target+effects+of+inhibitors+can+result+in+over/underestimation+of+cell+viability.">Pitfalls of the MTT assay: Direct and off-target effects of inhibitors can result in over/underestimation of cell viability.</a> Gene. 574 (2), 193-203 (2015).</li></ol>

Under de senaste decennierna har heterologa uttryck system använts att uttrycka och isolera stora mängder proteiner, vilket möjliggör biokemiska och funktionell bestämning och karakterisering av enzymer in vitro. Hittills har flera olika modellsystem inklusive Escherichia coli, Pichia pastoris, Sacccharomyces cerevisiaeoch Spodoptera frugiperda har anpassats för rekombinant proteinuttryck, och valet av den in vitro -system är avgörande för storskaliga generat...

Insektsmedel motstånd är för närvarande en huvudfråga hus flugkontroll världsomspännande1,2. Ansträngningar för att fastställa mekanismen av insektsmedel motstånd underlättar bättre förståelse av problemet och ger därmed nya strategier för att effektivt förhindra eller minimera spridning av resistens utveckling3. Carboxylesterases, har som en av de stora avgiftning enzymerna, lockat en hel del uppmärksamhet för sina roller i komplexbildare och metaboliserar insekticider i olika insekter4,5,6. Vår tidigare studie har identifierat flera carboxylesterases i hus flugor och deras uttryck nivåer var inte bara konstitutivt uppreglerat i den resistent ALHF stammen men kan också induceras till högre nivåer som svar på permetrin behandlingar7 . De funktionella karakteriseringar av dessa karboxylesteras gener i metaboliserande insekticider återstår dock undersökas.
Sedan den första rapporten i början av 1980-talet8, har en baculoviridae-medierad utländska gen uttryck system varit allmänt anställd på grund av dess höga protein produktionseffektivitet och eukaryota protein bearbetning kapacitet9. Denna binära systemet består av två grundläggande element: den konstruerade rekombinant baculoviridae att leverera främmande gener i värdcellerna och storskaliga uttrycket av intresserade av proteiner av celler som smittats av rekombinant baculoviridae. Under de senaste decennierna, baculoviridae medierad cell uttryck systemet har använts i stor utsträckning att producera tusentals rekombinanta proteiner, alltifrån cytosoliska enzymerna till membran-bundna proteiner i insekt och däggdjurs celler10. Vår tidigare studie har framgångsrikt uttryckte flera CYP450-enzymer i insekt Sf9 celler med detta system11. I denna studie vi konstruerade en karboxylesteras-rekombinant baculoviridae för att infektera insekt Sf9 celler, utforskade den cell toleransen mot olika permetrin behandlingar och storskaliga uttryckt karboxylesteras proteiner i vitro för funktionell utforskning. Istället för att undersöka flera karboxylesteras isozymet blandningar från insekt homogenates antagits av tidigare studier12,13, detta baculoviridae-medierad insekt cell uttryck systemet tillåter det specifika uttrycket och isolering av riktade proteiner för bättre karaktärisering av deras biokemiska och strukturella egenskaper.
Tetrazolium saltbaserade analysen (MTT) är en hög genomströmning kolorimetrisk metod utvecklad och optimerad för att mäta cellviabilitet. Denna analys bygger på den mekanism som endast levande celler kan av metaboliserande gul-färgade MTT reagens till en mörk lila färgade formazan fällning, som kan analyseras kolorimetriskt efter upplöst i organiska lösningsmedel14, 15. Flera mer exakt, men tidskrävande metoder, såsom Trypan blå utslagning och tymidin titrering assay16,17, har utvecklats under de senaste åren. Cellbaserade MTT analysen redovisas dock fortfarande närvarande som den mest snabb och lättmanövrerad metoden att snabbt upptäcka cellviabilitet. Här, använder vi MTT analysen för att utforska cell toleransen mot insektsmedel behandlingar. Förbättrad tolerans av celler när infekterade med karboxylesteras rekombinant baculoviridae starkt stöder carboxylesterases till insekticider, vilket i sin tur tyder på deras engagemang i insektsmedel motstånd metabola roller.
Dessutom genomfördes ett in vitro- metabola test också i denna studie. Jämfört med allmänna karboxylesteras analyser som använder vanliga substrat såsom α-napthyl acetat (α-NA) och β-naftyl acetat (β-NA) för att återspegla hydrolytiska verksamhet av carboxylesterases, betraktas in vitro- metabola studien som ett korrekt sätt att direkt mäta aktiviteter av carboxylesterases mot insekticider18. Denna metod har använts framgångsrikt i olika insekter att karakterisera flera cytokrom P450s i samband med insektsmedel motstånd11,19,20. Men har denna metod ännu inte tillämpats i karboxylesteras studier. Med tillgängligheten av karboxylesteras proteiner som produceras av baculoviridae-medierade uttryck systemet, kan vi utföra en in vitro- metabola studie av carboxylesterases mot permetrin, vilket ytterligare kan ge starka bevis för inblandning av carboxylesterases i ger pyretroidbaserade resistens i hus flyger.

<table>
	<tbody>
		<tr>
			<td>Q5 High-Fidelity DNA Polymerase</td>
			<td>New England Biolabs inc.</td>
			<td>M0491L</td>
			<td></td>
		</tr>
		<tr>
			<td>QIAquick Gel Extraction Kit</td>
			<td>QIAGEN</td>
			<td>28704</td>
			<td></td>
		</tr>
		<tr>
			<td>pENTR/D-TOPO Cloning Kit, with One Shot TOP10 Chemically Competent E. coli</td>
			<td>Invitrogen by life technology</td>
			<td>K240020</td>
			<td>S.O.C medium and universal M13 sequence primers were included in this kit.</td>
		</tr>
		<tr>
			<td>PureLink HiPure Plasmid Miniprep Kit</td>
			<td>Invitrogen by life technology</td>
			<td>K210002</td>
			<td></td>
		</tr>
		<tr>
			<td>Gateway LR Clonase II Enzyme mix for BaculoDirectTM Kits</td>
			<td>Invitrogen by life technology</td>
			<td>11791-023</td>
			<td></td>
		</tr>
		<tr>
			<td>BaculoDirect C-Term Linear DNA Transfection Kit</td>
			<td>Invitrogen by life technology</td>
			<td>12562-019</td>
			<td>Cellfectin transfection reagent and ganciclovir were included in this kit</td>
		</tr>
		<tr>
			<td>pENTR-CAT plasmid</td>
			<td>Invitrogen by life technology</td>
			<td></td>
			<td>Included in BaculoDirect C-Term Linear DNA Transfection Kit, concentration: 0.5 ug/uL</td>
		</tr>
		<tr>
			<td>Heat inactivated Fetal Bovine Serum, Certified</td>
			<td>Gibco by Life Technologies</td>
			<td>10082-139</td>
			<td></td>
		</tr>
		<tr>
			<td>Sf9 cells in Sf-900 III SFM</td>
			<td>Gibco by Life Technologies</td>
			<td>12659017</td>
			<td></td>
		</tr>
		<tr>
			<td>Insect Cell-PE LB Insect Cell Protein Extraction &#38; Lysis Buffer</td>
			<td>G Biosciences by A Geno Technology Inc</td>
			<td>786-411</td>
			<td></td>
		</tr>
		<tr>
			<td>Sf-900 III SFM (1&#215;) Serum Free Medium Complete</td>
			<td>Gibco by Life Technologies</td>
			<td>12658-019</td>
			<td></td>
		</tr>
		<tr>
			<td>Grace&#39;s Insect Medium, unsupplemented</td>
			<td>Gibco by Life Technologies</td>
			<td>11595030</td>
			<td></td>
		</tr>
		<tr>
			<td>Permethrin (isomers) analytical standard</td>
			<td>SUPELCO by Solutions WithinTM</td>
			<td>442748</td>
			<td></td>
		</tr>
		<tr>
			<td>Methanol (analytical graded)</td>
			<td>Sigma-Aldrich</td>
			<td>67-56-1</td>
			<td></td>
		</tr>
		<tr>
			<td>Acetonitrile (analytical graded)</td>
			<td>Sigma-Aldrich</td>
			<td>75-05-8</td>
			<td></td>
		</tr>
		<tr>
			<td>GHP Acrodisc 25 mm Syringe Filters with 0.45 &#956;m GHP Membrane (HPLC Certified)</td>
			<td>Pall Life Sciences</td>
			<td>21890388</td>
			<td></td>
		</tr>
		<tr>
			<td>Alliance Waters 2695 HPLC System</td>
			<td>Waters</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>T100 Thermal Cycle</td>
			<td>Bio-Rad Laboratories Inc.</td>
			<td>1861096</td>
			<td></td>
		</tr>
		<tr>
			<td>Nanodrop 2000/2000c Spectrophotometers</td>
			<td>ThermoFisher Scientific</td>
			<td>ND2000CLAPTOP</td>
			<td></td>
		</tr>
		<tr>
			<td>Cytation 5 Cell Imaging Multi-Mode Reader</td>
			<td>BioTek</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

functional characterization of carboxylesterases in insecticide resistant house flies, musca domestica

Karboxylesteras-medierad metabolism tros spela en viktig roll i insektsmedel resistens hos olika insekter. Flera karboxylesteras gener hittades uppreglerat i resistenta house fly stam, medan deras roller i ger insektsmedel resistens återstod för att utforskas. Här har vi utformat ett protokoll för funktionell karakterisering av carboxylesterases. Tre exempel experiment presenteras: (1) uttryck och isolering av karboxylesteras proteiner genom en baculoviridae-medierad insekt Spodoptera frugiperda (Sf9) cell uttryck systemet; (2) en cellbaserade MTT (3-[4, 5-dimethykthiazol-2-yl] -2, 5-diphenyltetrazolium bromid) cytotoxicitet analys att mäta toleransen av insekt celler på olika permetrin behandlingar. och (3) i vitro metabola studier att utforska de metaboliska funktionerna i carboxylesterases mot permetrin. Karboxylesteras genen MdαE7 klonats från en resistent hus flyga stam ALHF och används för att konstruera en rekombinant baculoviridae Sf9 celler angripits. De cellen förmåga mot olika permetrin behandlingar mättes med MTT-analys. Förbättrad cell toleransen för den experimentella gruppen (MdαE7-rekombinant baculoviridae infekterade celler) jämfört med kontrollgrupperna (CAT-rekombinant baculoviridae infekterade celler och GFP-rekombinant baculoviridae infekterade celler) till permetrin behandlingar föreslås funktionerna i MdαE7 i metaboliserande insekticider, därigenom skydda celler från kemiska skador. Förutom att var karboxylesteras proteiner uttrycks i insekt Sf9 celler och isolerade för att genomföra en in vitro- metabola studie. Våra resultat visade en betydande in vitro- metabolisk effektivitet av MdαE7 mot permetrin, som direkt visar medverkan av carboxylesterases i metaboliserande insekticider och således ger insektsmedel resistens i hus flyger.

Cellviabiliteten mot olika permetrin behandlingar (MTT assay)
Cytotoxiciteten hos permetrin undersöktes i MdαE7-rekombinant baculoviridae infekterade Sf9 (experimentgruppen) och katt-rekombinant baculoviridae (tillhandahålls av baculoviridae infekterade kit) infekterade celler (kontrollgrupperna). Förbättrad cell toleranser att permetrin i MdαE7 uttrycker cellerna starkt stödja detta karboxylesteras mot insekticider och där...

Watch this Scientific Journal Video about Functional Characterization of Carboxylesterases in Insecticide Resistant House Flies, Musca Domestica at JoVE.com

Functional Characterization of Carboxylesterases in Insecticide Resistant House Flies, Musca Domestica

Här presenterar vi ett protokoll för att producera house fly karboxylesteras proteiner i vitro med en baculoviridae medierad insekt cell uttryck systemet och senare funktionellt präglar deras roller i Fettnedbrytande permetrin, därmed ger pyretroidbaserade motstånd av cellbaserade MTT assay och in vitro- metaboliska studier.

Funktionell karakterisering av Carboxylesterases i insektsmedel resistenta hus flugor, Musca Domestica

Carboxylesterase-mediated metabolism is thought to play a major role in insecticide resistance in various insects. Several carboxylesterase genes were ...

This method can help the key questions in the field of insect toxicology, such as, if all express the metabolic detoxification genes are involved in insecticide resistance? The main advantage of this technique is that it allows to produce larger scales of proteins, and characterize the function of these proteins in metabolizing of insecticides in vitro. Demonstrating the procedures, will be Xuechun Feng, a grad student in my laboratory.Xuechen's PhD research is focused on the characterization of function of carboxyl esterase in parasite resistance of house flies, Musca domestica. To begin, mix one microliter of GFP entry plasma DNA, with five microliters of a commercially available C-term linear DNA in 250 microliter PCR tubes. Next, add two microliters of commercially available lambda recombination mix to each of the PCR tubes.Gently mix the tubes, and incubate them at 25 degrees Celsius overnight. Seed two milliliters of log phase growth insect SF9 cell culture evenly to the wells of a cell culture plate. Then allow the cells to attach for at least three hours at room temperature, in the hood.Using an inverted phase microscope at 250x, check the cell attachment. Then, remove the cell culture medium, and replace it with two milliliters of Grace's insect medium. After this, prepare transfection mixture A and B solutions according to the text protocol.Then gently mix transfection mixtures A and B together by tapping the tubes. Incubate the mixture at room temperature, in the hood, for 35 minutes. Next, add the mixture drop-wise, onto the seeded cells.Seal the wells with tape, and incubate the cells at 27 degrees Celsius, overnight. Replace the two milliliters of Grace's insect medium, with two milliliters of complete growth medium. Then, add 100 micromole Ganciclovir, to each well.Seal the wells with tape, and incubate the cells at 27 degrees Celsius for 72 hours. 72 hours post-infection, collect the medium from each well, and transfer it to 1.5 milliliter centrifuge tubes. Then centrifuge the tubes at 1500 times G, for five minutes at four degrees Celsius.Add one milliliter of complete growth medium to the well, and use a microscope with fluorescent light, to observe the infection signs of cells at the P1 baculovirus amplification stage. Transfer the supernatant into new 1.5 milliliter centrifuge tubes, and store them at four degrees Celsius, in dark conditions. After this, seed two milliliters of log phase growth insect SF9 cell culture, evenly, in the wells of a cell culture plate.Allow the cells to attach for at least three hours at room temperature, in the hood. Inoculate five microliters of P1 virus stock into the cell seeded wells, then, add 100 micromole Ganciclovir to each well. Seal the wells, and incubate the cells for 72 hours at 27 degrees Celsius.First, culture five milliliters of log phase growth insect SF9 cells, with complete growth medium, in T25 non-treated flasks. Then, add 25 microliters of P1 virus stock solution to infect the cell culture, for 48 hours, with gentle shaking, at 27 degrees Celsius. Using acetonitrile, prepare serial dilutions of 100 millimole permethrin.Then, seed 200 microliters of infected cell culture supplemented with 300 microliters of complete growth media, into a 24 well plate. Making sure that permethrin is fully dissolved in the acetonitrile, and evenly delivered into each well of the plate. After adding the permethrin, gently shake the plate to fully mix the permethrin in the medium.After this, seal the plate with tape, and incubate the plate at 27 degrees Celsius, for 48 hours, in dark conditions. Remove the cell culture medium from the plate without disturbing the bottom attached cell layer. Add 200 microliters of the MMT reagent to each well.Then, incubate the plate at 37 degrees Celsius for four hours, until dark purple formazan precipitants form in each well. Add 500 microliters of DMSO to each well, to fully dissolve the precipitants. Then transfer 200 microliters of the dissolved solution, to each well of a 96 well plate.Fully dissolving the precipitate into DMSO is crucial for the accuracy of the results. After adding the DMSO into samples in the plate, the samples will be washed using the pipette, for several times, until the precipitate has been fully dissolved. Finally, use a microplate reader to measure the absorbance values of the plate at 540 nanometers.At the P1 stage, the infection ratio is low. At the P2 stage, the infection ratio was significantly enhanced. At the P3 infection stage, almost all the cells showed symptoms of detachment from the cell culture plate, increases of cell diameter, as well as the cessation of cell growth.Based on the detected absorbance values, the Md alpha E7 expressing cells showed significantly higher viability, compared to the control CAT cells. While conducting this procedure, it is important to prevent cell contamination in all steps, by wiping the surface of stuffs, such as bottles and tubes, with 70 percentage ethanol before conducting the cell experiments. Following this procedure, some other methods, like the homology modeling and dark analysis, can be performed in order to answer additional questions, like the interactions between carboxyl esterase protein and permethrin ligand.This technique paved the way for the researchers in the insect toxicology, to explore the functional characterization of the genes and mechanisms in insecticide resistance of insects. Don't forget that working with insecticide can be very harmful, and precautions, such as gloves and lab coats, should always be taken while conducting these procedures.

Research

JoVE Journal

Biochemistry

Functional Characterization of Carboxylesterases in Insecticide Resistant House Flies, Musca Domestica

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