Research in NC lab is supported by a National Institutes of Health (NIH) grant R01AI24499 and a New Jersey Health Foundation (NJHF) grant, #PC40-18.

NOTE: The detailed stepwise protocol of the assay is described below, and the schematic protocol is shown in Figure 1.
1. C. albicans strains and growth conditions
<ol>
	<li>Grow the C. albicans strains&#160;in liquid Yeast Extract-Peptone-Dextrose (YPD) medium at 30 &#176;C in an incubator shaker overnight. 
	NOTE: Maintain Candida strains as frozen stocks and grow on YPD agar (1 % yeast extract, 2% peptone, 2% dextrose,...

<ol>
	<li>Brown, G. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hidden+killers:+human+fungal+infections.">Hidden killers: human fungal infections.</a> Science Translational Medicine. 4 (165), (2012).</li><li>Wisplinghoff, 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=Nosocomial+bloodstream+infections+in+US+hospitals:+analysis+of+24,179+cases+from+a+prospective+nationwide+surveillance+study.">Nosocomial bloodstream infections in US hospitals: analysis of 24,179 cases from a prospective nationwide surveillance study.</a> Clinical Infectious Diseases. 39 (3), 309-317 (2004).</li><li>Ascioglu, 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=Defining+opportunistic+invasive+fungal+infections+in+immunocompromised+patients+with+cancer+and+hematopoietic+stem+cell+transplants:+an+international+consensus.">Defining opportunistic invasive fungal infections in immunocompromised patients with cancer and hematopoietic stem cell transplants: an international consensus.</a> Clinical Infectious Diseases. 34 (1), 7-14 (2002).</li><li>Stover, B. 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=Nosocomial+infection+rates+in+US+children's+hospitals'+neonatal+and+pediatric+intensive+care+units.">Nosocomial infection rates in US children's hospitals' neonatal and pediatric intensive care units.</a> American Journal of Infection Control. 29 (3), 152-157 (2001).</li><li>Wilson, L. 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=The+direct+cost+and+incidence+of+systemic+fungal+infections.">The direct cost and incidence of systemic fungal infections.</a> Value in Health. 5 (1), 26-34 (2002).</li><li>Wenzel, R. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nosocomial+candidemia:+risk+factors+and+attributable+mortality.">Nosocomial candidemia: risk factors and attributable mortality.</a> Clinical Infectious Diseases. 20 (6), 1531-1534 (1995).</li><li>Wisplinghoff, 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=Nosocomial+bloodstream+infections+in+pediatric+patients+in+United+States+hospitals:+epidemiology,+clinical+features+and+susceptibilities.">Nosocomial bloodstream infections in pediatric patients in United States hospitals: epidemiology, clinical features and susceptibilities.</a> Pediatric Infectious Disease Journal. 22 (8), 686-691 (2003).</li><li>Cheng, W. C., Leach, K. M., Hardwick, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mitochondrial+death+pathways+in+yeast+and+mammalian+cells.">Mitochondrial death pathways in yeast and mammalian cells.</a> Biochimica et Biophysica Acta. 1783 (7), 1272-1279 (2008).</li><li>Shingu-Vazquez, M., Traven, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mitochondria+and+fungal+pathogenesis:+drug+tolerance,+virulence,+and+potential+for+antifungal+therapy.">Mitochondria and fungal pathogenesis: drug tolerance, virulence, and potential for antifungal therapy.</a> Eukaryotic Cell. 10 (11), 1376-1383 (2011).</li><li>Brown, A. J., Brown, G. D., Netea, M. G., Gow, N. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metabolism+impacts+upon+Candida+immunogenicity+and+pathogenicity+at+multiple+levels.">Metabolism impacts upon Candida immunogenicity and pathogenicity at multiple levels.</a> Trends in Microbiology. 22 (11), 614-622 (2014).</li><li>Tucey, T. 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=Glucose+Homeostasis+Is+Important+for+Immune+Cell+Viability+during+Candida+Challenge+and+Host+Survival+of+Systemic+Fungal+Infection.">Glucose Homeostasis Is Important for Immune Cell Viability during Candida Challenge and Host Survival of Systemic Fungal Infection.</a> Cell Metabolism. 27 (5), 988-1006 (2018).</li><li>Barelle, 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=Niche-specific+regulation+of+central+metabolic+pathways+in+a+fungal+pathogen.">Niche-specific regulation of central metabolic pathways in a fungal pathogen.</a> Cellular Microbiology. 8 (6), 961-971 (2006).</li><li>Carman, A. J., Vylkova, S., Lorenz, 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=Role+of+acetyl+coenzyme+A+synthesis+and+breakdown+in+alternative+carbon+source+utilization+in+Candida+albicans.">Role of acetyl coenzyme A synthesis and breakdown in alternative carbon source utilization in Candida albicans.</a> Eukaryotic Cell. 7 (10), 1733-1741 (2008).</li><li>Fradin, C., 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=Granulocytes+govern+the+transcriptional+response,+morphology+and+proliferation+of+Candida+albicans+in+human+blood.">Granulocytes govern the transcriptional response, morphology and proliferation of Candida albicans in human blood.</a> Molecular Microbiology. 56 (2), 397-415 (2005).</li><li>Lorenz, M. C., Bender, J. A., Fink, G. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transcriptional+response+of+Candida+albicans+upon+internalization+by+macrophages.">Transcriptional response of Candida albicans upon internalization by macrophages.</a> Eukaryotic Cell. 3 (5), 1076-1087 (2004).</li><li>Ramirez, M. A., Lorenz, 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=Mutations+in+alternative+carbon+utilization+pathways+in+Candida+albicans+attenuate+virulence+and+confer+pleiotropic+phenotypes.">Mutations in alternative carbon utilization pathways in Candida albicans attenuate virulence and confer pleiotropic phenotypes.</a> Eukaryotic Cell. 6 (2), 280-290 (2007).</li><li>Bambach, 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=Goa1p+of+Candida+albicans+localizes+to+the+mitochondria+during+stress+and+is+required+for+mitochondrial+function+and+virulence.">Goa1p of Candida albicans localizes to the mitochondria during stress and is required for mitochondrial function and virulence.</a> Eukaryotic Cell. 8 (11), 1706-1720 (2009).</li><li>Li, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enzymatic+dysfunction+of+mitochondrial+complex+I+of+the+Candida+albicans+goa1+mutant+is+associated+with+increased+reactive+oxidants+and+cell+death.">Enzymatic dysfunction of mitochondrial complex I of the Candida albicans goa1 mutant is associated with increased reactive oxidants and cell death.</a> Eukaryotic Cell. 10 (5), 672-682 (2011).</li><li>Desai, C., Mavrianos, J., Chauhan, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Candida+albicans+SRR1,+a+putative+two-component+response+regulator+gene,+is+required+for+stress+adaptation,+morphogenesis,+and+virulence.">Candida albicans SRR1, a putative two-component response regulator gene, is required for stress adaptation, morphogenesis, and virulence.</a> Eukaryotic Cell. 10 (10), 1370-1374 (2011).</li><li>Mavrianos, 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=Mitochondrial+two-component+signaling+systems+in+Candida+albicans.">Mitochondrial two-component signaling systems in Candida albicans.</a> Eukaryotic Cell. 12 (6), 913-922 (2013).</li><li>Koch, 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=The+Mitochondrial+GTPase+Gem1+Contributes+to+the+Cell+Wall+Stress+Response+and+Invasive+Growth+of+Candida+albicans.">The Mitochondrial GTPase Gem1 Contributes to the Cell Wall Stress Response and Invasive Growth of Candida albicans.</a> Frontiers in Microbiology. 8, 2555 (2017).</li><li>Qu, 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=Mitochondrial+sorting+and+assembly+machinery+subunit+Sam37+in+Candida+albicans:+insight+into+the+roles+of+mitochondria+in+fitness,+cell+wall+integrity,+and+virulence.">Mitochondrial sorting and assembly machinery subunit Sam37 in Candida albicans: insight into the roles of mitochondria in fitness, cell wall integrity, and virulence.</a> Eukaryotic Cell. 11 (4), 532-544 (2012).</li><li>Brandt, 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=.">.</a> Candida and Candidiasis. , (2002).</li><li>Huh, W. K., Kang, S. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+cloning+and+functional+expression+of+alternative+oxidase+from+Candida+albicans.">Molecular cloning and functional expression of alternative oxidase from Candida albicans.</a> Journal of Bacteriology. 181 (13), 4098-4102 (1999).</li><li>Yan, 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=The+alternative+oxidase+of+Candida+albicans+causes+reduced+fluconazole+susceptibility.">The alternative oxidase of Candida albicans causes reduced fluconazole susceptibility.</a> Journal of Antimicrobial Chemotherapy. 64 (4), 764-773 (2009).</li><li>de Moura, M. B., Van Houten, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bioenergetic+analysis+of+intact+mammalian+cells+using+the+Seahorse+XF24+Extracellular+Flux+analyzer+and+a+luciferase+ATP+assay.">Bioenergetic analysis of intact mammalian cells using the Seahorse XF24 Extracellular Flux analyzer and a luciferase ATP assay.</a> Methods in Molecular Biology. 1105, 589-602 (2014).</li></ol>

The authors have nothing to disclose

The bioenergetics extra flux assay serves as an excellent tool to read out the mitochondrial function by measuring oxidative phosphorylation (OXPHOS)-dependent oxygen consumption in real-time. In addition, a glycolytic function which is measured as an extracellular acidification rate (change in extracellular pH) can also be investigated at the same time in real-time analysis.
Successful plating of C. albicans in the assay plate is one of the critical steps in the assay because the inc...

Invasive fungal infections kill over 1.5 million people a year worldwide. This number is on the rise due to an increase in the numbers of people living with compromised immunity, including the elderly, premature infants, transplant recipients, and cancer patients1. C. albicans is an opportunistic human fungal pathogen that is a part of the human microflora. It also inhabits mucosal surfaces and the gastrointestinal tract as a commensal organism. C. albicans produces serious systemic disease in people who have immune deficiencies, who have undergone surgery, or who have been treated with long courses of antibiotics. The Candida species rank among the top three to four causes of nosocomial infectious diseases (NID) in humans2,3,4,5,6,7. The annual global number of Candida bloodstream infections is estimated to be ~400,000 cases, with associated mortalities of 46-75%1. The annual mortality because of candidiasis is roughly 10,000 in the United States alone. The extent of NID caused by fungi is also reflected in astronomical patient expenses5. In the United States, the yearly expense for the treatment of invasive fungal infections surpasses $2 billion, adding a huge strain to already overburdened health care system. Currently, available standard antifungal therapies are limited because of toxicity, increasingly prevalent drug resistance, and drug-drug interactions. Therefore, there is an urgent need to identify new antifungal drug targets that will result in better treatment options for high-risk patients. However, the discovery of new drugs acting on fungal targets is complicated because fungi are eukaryotes. This greatly limits the number of fungal-specific drug targets.
Recent studies have indicated that mitochondria are a critical contributor to the fungal virulence and tolerance to antifungal drugs since mitochondria are important for cellular respiration, oxidative metabolism, signal transduction, and apoptosis8,9,10,11. Both glycolytic and non-glycolytic metabolism are essential for the survival of C. albicans in the mammalian host12,13,14,15,16. Furthermore, several C. albicans mutants lacking mitochondrial proteins, such as Goa1, Srr1, Gem1, Sam37 etc. have been shown to be defective in filamentation, an important virulence factor of C. albicans17,18,19,20,21,22. In addition, these mutants were also shown to be attenuated for virulence in a mouse model of disseminated candidiasis17,18,19,20,21,22. Thus, fungal mitochondria represent an attractive target for drug discovery. However, the study of mitochondrial function in C. albicans is challenging because C. albicans is petite negative23, which means that it cannot survive without the mitochondrial genome.
Here, we describe a protocol that can be used to investigate mitochondrial and glycolytic function in C. albicans without the need to purify mitochondria. This method can also be optimized to investigate the effect of the genetic manipulation or chemical modulators on mitochondrial and glycolytic pathways in C. albicans.

<table border="0" cellpadding="0" cellspacing="0" style="width:664px;" width="664">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">RPMI 1640</td>
			<td style="width:84px;">Corning</td>
			<td style="width:119px;">MT50020PB</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">Antimycin A</td>
			<td style="width:84px;">Sigma</td>
			<td>A8674</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">KCN</td>
			<td style="width:84px;"></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">Mito stress kit</td>
			<td style="width:84px;">Agilent</td>
			<td>103015-100</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">Oligomycin</td>
			<td style="width:84px;">Calbiochem</td>
			<td>495455</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">pH meter</td>
			<td style="width:84px;">Accumet</td>
			<td>AR20</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">Phenol red</td>
			<td style="width:84px;">Sigma</td>
			<td>P5530</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">Poly-D lysine</td>
			<td style="width:84px;">Sigma</td>
			<td>P6407</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">Rotenone</td>
			<td style="width:84px;">Santa cruz</td>
			<td>203242</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Seahorse XF24 FluxPak</td>
			<td style="width:84px;">Agilent</td>
			<td>100850-001</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">SHAM</td>
			<td style="width:84px;"></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">Sodium Chloride</td>
			<td style="width:84px;">Amresco&#160;</td>
			<td>241</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">Sodium hydroxie pellets</td>
			<td style="width:84px;">J.T Baker</td>
			<td>3722</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">Tissue culture grade water</td>
			<td style="width:84px;">Gibco</td>
			<td>1523-0147</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">XF assay calibrant solution</td>
			<td style="width:84px;">Agilent</td>
			<td>100840-000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">Yeast extract Peptone Dextrose</td>
			<td>Fisher scientific,</td>
			<td>BP2469</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">Yeast extract Peptone Dextrose Agar</td>
			<td style="width:84px;">Sigma</td>
			<td>A1296</td>
			<td></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:295px;">Yeast extract Peptone Glycerol</td>
			<td style="width:84px;">Sigma</td>
			<td>G2025</td>
			<td></td>
		</tr>
	</tbody>
</table>

bio-energetics investigation of candida albicans using real-time extracellular flux analysis

Mitochondria are essential organelles for the cellular metabolism and survival. A variety of key events take place in mitochondria, such as cellular respiration, oxidative metabolism, signal transduction, and apoptosis. Consequently, mitochondrial dysfunction is reported to play an important role in the antifungal drug tolerance and virulence of pathogenic fungi. Recent data have also led to the recognition of the importance of the mitochondria as an important contributor to fungal pathogenesis. Despite the importance of the mitochondria in fungal biology, standardized methods to understand its function are poorly developed. Here, we present a procedure to study the basal oxygen consumption rate (OCR), a measure of mitochondrial respiration, and extracellular acidification rates (ECAR), a measure of glycolytic function in C. albicans strains. The method described herein can be applied to any Candidaspp. strains without the need to purify mitochondria from the intact fungal cells. Furthermore, this protocol can also be customized to screen for inhibitors of mitochondrial function in C. albicans strains.

The focus of this protocol is to determine the bioenergetic functions of C. albicans assessed by extra flux analyzer. A C. albicans mutant lacking mitochondrial protein Mam33 is also included along with its complement strain, mam33&#916;/&#916;::MAM33 to study the effects of the deletion of a mitochondrial protein on OCR and ECAR. MAM33 encodes for a putative mitochondrial acidic matrix protein and its function in Candida is not known.
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Watch this Scientific Journal Video about Bio-energetics Investigation of Candida albicans Using Real-time Extracellular Flux Analysis at JoVE.com

Bio-energetics Investigation of Candida albicans Using Real-time Extracellular Flux Analysis

Here, we present a stepwise protocol to investigate the mitochondrial respiration and glycolytic function in Candida Albicans using an extra flux analyzer.

Bio-energetics Investigation of Candida albicans Using Real-time Extracellular Flux Analysis

Mitochondria are essential organelles for the cellular metabolism and survival. A variety of key events take place in mitochondria, such as cellular ...

This protocol is significant for determining the glycolytic function and mitochondrial respiration in Candida albicans. The main advantage of this technique is that it allows for mitochondrial function to be measured without the need to purify mitochondria from Candida albicans. This method can be optimized to investigate the effects of genetic manipulation or chemical modulators on mitochondrial and glycolytic pathways in Candida albicans or other fungal pathogens.This technique is relatively simple. Or depending on the organism, their use may help to optimize the cell number and the concentration of mitochondrial inhibitors in their assay. In a laminar flow hood, dissolve Poly-D-Lysine in tissue grid water to a final concentration of 50 micrograms per milliliter.Mix the solution well and aliquot it into 1.5 milliliter microcentrifuge tubes making sure to aliquot at least 1.3 milliliters per tube. Add 50 microliters of this mixture to each well of the assay plate, cover the lid and incubate at room temperature for one to two hours. Then aspirate the solution.Rinse the wells of the assay plate once with 500 microliters of sterile tissue culture grade water, open the lid and allow the wells to air dry. If not using the plate the day it is prepared, store it at four degrees Celsius for a maximum of two to three days. The day before the experiment, open the extra flux assay kit and remove the contents.Place the sensor cartridge upside down next to the utility plate. Fill each well of the utility plate with one milliliter of calibrant and then place the sensor cartridge back. Make sure the sensors that contain fluorophores are submerged in the calibrant.Incubate the sensor cartridge at 37 degrees Celsius in a non-carbon dioxide incubator overnight. The day before the assay, inoculate the prepared C albicans in the YPD broth and grow overnight at 30 degrees Celsius in a shaker at 200 rpm. On the day of the assay, dilute an appropriate number of cells in the assay medium to yield a final concentration of 100, 000 cells per 100 microliters.Add 100 microliters of the diluted cells into each well of the assay plate except wells A1, B4, C3, and D6.To these wells, add only 100 microliters of assay medium for background correction. Incubate the plate at 37 degrees Celsius in a non-carbon dioxide incubator for 60 minutes to let the cells adhere to the plate surface. Prepare the compounds for the mitochondrial function assay at 10X concentration in the corresponding assay medium as outlined in the text protocol.Add 50 microliters of SHAM into port A, 50 microliters of Oligomycin into port B, 62 microliters of potassium cyanide into port C, and 68 microliters of Antimycin A into port D.Next, prepare the compounds for the glycolytic stress assay at 10X concentration in the corresponding assay medium as outlined in the text protocol. Add 50 microliters of glucose to port A, 55 microliters of Oligomycin into port B, 62 microliters of 2-DG into port C, and 68 microliters of Antimycin A into port D.Before the assay, open the extra flux analyzer and set up the assay template by using the assay wizard tab. Follow the step-by-step instructions and fill out all of the information that pop out during the setup.Generate a group layout and set up the protocol as outlined in the text protocol. Save these layouts before the assay. At the time of the assay, restore the saved protocol by opening the corresponding file in the open file option in the assay wizard tab.Then load the 10X compounds into the respective ports of the hydrated sensor cartridge containing the calibrant. Load the sensor cartridge into the carrier tray of the extra flux analyzer. Start the calibration by clicking the start button on the screen.Next, gently add 350 microliters of the assay medium to the cell plate along the side of the walls to minimize cell disturbance bringing the final volume to 450 microliters. Replace the utility plate containing the calibrant with the assay plate and continue the assay. Once the assay is completed, remove the sensor cartridge and the plate.Save the file in the appropriate destination folder. In this study, the bio-energetic functions of the C albicans are assessed by extra flux analyzer. A mutant lacking the mitochondrial protein mam33 is also included along with its complement strain to study the effects of the deletion of a mitochondrial protein on oxygen consumption rate and extracellular acidification rates.The C albicans wild type shows an oxygen consumption rate of 145 picomoles per minute which is well within the optimal range for any extracellular flux assay. The basal oxygen consumption rate of the wild type, mam33 mutant and mam33 complemented strains show no differences. Similarly, no significant differences are seen in the basal extracellular acidification rates between the strains.However, by inhibiting complex-IV with potassium cyanide, the wild type and mam33 mutant, mam33 complemented strains show a significant shift toward the glycolysis. The mam33 mutant strain however failed to show a compensatory glycolytic shift suggesting that the compound-IV dependent pathway is impaired in this strain. In the glycolytic stress test, cells are starved of glucose for one hour and the basal oxygen consumption rate and extracellular acidification rate is measured.Upon starvation, the mam33 mutant strain show significantly lower oxygen consumption and extracellular acidification rates compared to the other strains. This suggests an impaired utilization of glucose for both respiration and glycolysis when cells are forced to the starvation condition. After injecting glucose, all strains show stimulation of both their oxygen consumption rate and extracellular acidification rate.The coating of assay plate allows Candida albicans cells to adhere to the plate. Improper adherence of Candida albicans cells will affect the assay result. After the development of this technique, it has been employed in a wide range of cell types and diseases addressing how mitochondria function during physiological and pathological conditions.For example, employing patient-derived and control cells in this assay, it is possible to address the specific questions of how mitochondrial function is altered. Care should be taken while preparing mitochondrial inhibitors such as potassium cyanide and antimycin A because these compounds are extremely poisonous.

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JoVE Journal

Medicine

6.8K visualizações.  The State University of New Jersey. Este protocolo é significativo para determinar a função glicolítico e a respiração mitocondrial em candida albicans. A principal vantagem dessa técnica é que ela permite que a função mitocondrial seja medida sem a necessidade de purificar mitocôndrias de candida albicans. Este método pode ser otimizado para investigar os efeitos da manipulação genética ou moduladores químicos em vias mitocondriais e glicolíticas em abicanos candida ou outros patógenos fúngicos.Esta t...