Research Article Viability Reagent, PrestoBlue, in ...downloads.hindawi.com/journals/ijmicro/2013/420601.pdf · of the positive drug controls against the various microor-ganisms

Hindawi Publishing CorporationInternational Journal of MicrobiologyVolume 2013 Article ID 420601 5 pageshttpdxdoiorg1011552013420601

Research ArticleViability Reagent PrestoBlue in Comparison withOther Available Reagents Utilized in Cytotoxicity andAntimicrobial Assays

Namrita Lall Cynthia Joan Henley-Smith Marco Nuno De CanhaCarel Basson Oosthuizen and Danielle Berrington

Department of Plant Science University of Pretoria Pretoria 0002 South Africa

Correspondence should be addressed to Danielle Berrington berringtondaniellegmailcom

Received 15 January 2013 Revised 14 March 2013 Accepted 14 March 2013

Academic Editor Michael Tunney

Copyright copy 2013 Namrita Lall et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

This study compared different commercially available viability reagents The growth indicator reagents include p-iodonitro-tetrazolium violet (INT) PrestoBlue and Alamar Blue which were used for antimicrobial analysis against Streptococcus mutansPrevotella intermedia Propionibacterium acnes and Mycobacterium tuberculosis PrestoBlue and Alamar Blue are resazurin basedreagents that resulted in a quick and easily distinguishable colour change that allowed for visual readings INT and Sodium31015840-[1-(phenyl amino-carbonyl)-34-tetrazolium]-bis-[4-methoxy-6-nitro] benzene sulfonic acid hydrate (XTT) are tetrazoliumbased reagents which are converted to a formazan dye in the presence of metabolically active mitochondria enzyme For cellviability analysis reagents XTT and PrestoBlue were compared PrestoBlue was able to clearly indicate the minimum inhibitoryconcentration (MIC) of various positive drug controls on various microbial strains PrestoBlue was also a good indicator of the50 inhibitory concentration (IC

50) of positive drug controls on various cell lines

1 Introduction

PrestoBlue and Alamar Blue reagents are resazurin basedmembrane permeable solutions that upon reduction form re-sorufin a red fluorescent compound which can be quanti-tatively measured to determine viability Initially developedas a cell viability indicator PrestoBlue has been indicatedfor use on nonmammalian cells such as bacteria yeast andeukaryotic cells The variable reading methods of PrestoBluemakes this reagent an attractive alternative in cellular andmicrobiology PrestoBlue can be measured either visuallyusing absorbance or utilising the fluorescent outputs of thereduced resorufin [1]

p-iodonitrotetrazolium violet (INT) is a tetrazolium dyeprecursor that once reduced forms a purple formazan dye(Sigma-Aldrich) Sodium 31015840-[1-(phenyl amino-carbonyl)-34-tetrazolium]-bis-[4-methoxy-6-nitro] benzene sulfonicacid hydrate (XTT) is also a tetrazolium based reagentswhich in the presence ofmetabolically active cells reduces the

tetrazolium salt to an orange coloured formazan compoundThe reduction of the tetrazolium salt is due to the activity ofthe mitochondria enzyme in the active cells The intensity ofthe formazan compound can be measured using absorbancewhere the intensity of the compound is directly proportionalto the number of metabolically active cells [2]

The aim of this study was to validate the use of PrestoBlueas a growth indicator and cell viability reagent by comparingit to other similar commercially available reagents

2 Materials and Methods

21 Chemicals and Reagents All microbial strains were pur-chased from American Type Culture Collection (ATCC)MD USA The A431 cell line and HeLa cell line were pur-chased from ECACC and Highveld Biological (Pty) Ltdrespectively INT was obtained from Sigma-Aldrich SouthAfrica PrestoBlue and Alamar Blue were both purchased

2 International Journal of Microbiology

from Invitrogen Corporation San Diego USA XTT cell pro-liferation Kit II was obtained from Roche Applied SciencesSouth Africa The cell culture medium trypsin-EDTA fetalbovine serum (FBS) phosphate buffer saline (PBS) andantibiotics were supplied by Highveld Biological (Pty) Ltd(Modderfontein Johannesburg RSA) All other reagentswere of analytical grade

22 Determination of the Minimum Inhibitory Concentration(MIC) for the Microbial Strains

221 Culturing ofMicroorganisms Themicroorganisms usedin this study included Prevotella intermedia (ATCC 25611)Streptococcus mutans (ATCC 25175) and Propionibacteriumacnes (ATCC 11827) S mutans and P intermedia were grownon Casein-peptone Soymeal-peptone Agar medium (CASO)enriched with 1 sucrose (Merck Chemicals (Pty) LtdWadeville South Africa) under anaerobic conditions in ananaerobic jar with Anaerocult A (Merck KGaA DarmstadtGermany) at 37∘C for 48 hrs Subculturing was done everysecond week Inoculants were prepared by suspending bacte-rial test organisms in quarter strength sterile Ringer solution(Merck KGaA Darmstadt Germany) until turbidity wascompatible with McFarland Standard 1 (Merck Chemicals(Pty) Ltd Wadeville South Africa) Furthermore a bacterialconcentration of 4 times 108 (colony forming units) CFUmL forP intermedia and 3 times 108 CFUmL for S mutans was used[3]

P acnes was cultured on Tryptone Soy Agar (MerckChemicals (Pty) Ltd Wadeville South Africa) under anaer-obic conditions in an anaerobic jar with Anaerocult A at37∘C for 72 hrs Subculturing was done every 4th week asthe doubling time of the bacterium is slow Inoculants wereprepared by suspending the bacterial colonies in NutrientBroth (Merck Chemicals (Pty) Ltd Wadeville South Africa)until turbidity was compatible with aMcFarland Standard 05at a bacterial concentration of 15 times 108 CFUmL [4]

222 Evaluation of MIC Values for Microorganisms Themicrodilution technique using 96-well microtitre plates asdescribed by Eloff [5] was used to obtain the MIC valuesof the positive drug controls against the various microor-ganisms The positive controls for oral bacteria chlorhexi-dine gluconate (CHX) (Dental Warehouse Sandton SouthAfrica) at 125 120583gmL and Tetracycline (Sigma-Aldrich 3050Spruce Street St Louis) at 200120583gmL for P acnes wereserially diluted in relevant broth medium adding 48 h oldoral bacteria and 72 h old P acnes and were incubated at37∘C in anaerobic conditions The final concentration ofCHX ranged 313120583gmLndash244times10minus2 120583gmL and Tetracyclineranged 100 120583gmLndash0781120583gmL S mutans and P interme-dia were incubated for 24 hrs and P acnes for 72 hrs at37∘C

To indicate bacterial growth 40120583L of (02mgmL) INT20120583LPrestoBlue and 20 120583LAlamarBluewas added tomicro-plate wells and reincubated until a colour change occurredThe MIC was defined as the lowest concentration thatinhibited the growth of the bacteria [6]

223 Evaluation of MIC against Mycobacterium tuberculosisFor the antimycobacterial assay the H37Rv (ATCC 27264)M tuberculosis strain was used The bacteria were culturedon Lowenstein-Jensen (LJ) medium (SA Medical ResearchCouncil Pretoria) for three weeks (37∘C 5 CO

2) One

colony was transferred under sterile conditions to 50mL of7H9 broth media (Sigma-Aldrich South Africa) 10 OADC(Sigma-Aldrich South Africa) and 2 PANTA (BectonDickinson and Company USA) The bacteria were furthercultured for one week After the final incubation period thebacteria were adjusted in 7H9 broth media to a turbidity ofa McFarland Standard 1 Bacterial suspensions were furtherdiluted 1 25 to obtain a concentration of 2times108 CFUmL [7]

TheMicrotitreAlamarBlue assay (MABA) andMicrotitrePrestoBlue assay (MPBA) were used to determine the MICof positive drug controls on the bacteria [7] Standard anti-tuberculosis agents INH (Sigma-Aldrich Becton Dickinsonand Company) and RIF (Sigma-Aldrich Becton Dickinsonand Company) were used Stock solutions were diluted in7H9 brothmedia to a final assay concentrationswhich ranged5 120583gmLndash0078120583gmL and 6 120583gmLndash01875120583gmL for INHand RIF respectively A 2 dimethyl sulfoxide (DMSO)solvent control media control and bacterial control wasincluded in the assay One hundred microlitres of bacteriawas added to the inner wells of the 96-well plates The outerperimeter wells were used to compensate for evaporationby adding 200120583L of dH

2O The plates were incubated for

5 to 7 days at 37∘C 5 CO2 After 5 days 20120583L of Alamar

BluePrestoBlue indicator solution was added to one of thebacterial control wells If a colour change was observed allthe subsequent wells received 20120583L of indicator solution Ifno colour change was observed the plates were incubated forfurther 24 hrs

23 Comparison of Growth Indicators for Cytotoxicity Analy-sis The HeLa and A431 cell lines were maintained in EaglersquosMinimum Essential Medium supplemented with 10 FBSand 1 antibiotics (100UmL penicillin 100 120583gmL strepto-mycin) and 250 120583gmL fungizone The cells were grown at37∘C in a humidified incubator set at 5 CO

2 Cells were

subcultured by treating them with trypsin-EDTA (025trypsin containing 001 EDTA) for 10 minutes

Cytotoxicity was measured using the XTT cell prolifer-ation Kit II and MPBA The method described by Zhenget al [8] was used to perform the assay Both cell lines wereseeded in a 96-well microtitre plate at a concentration of1 times 10

5 cellsmL Cells were allowed to attach for 24 hrs at37∘C and 5CO

2The cells were exposed to the positive drug

control Actinomycin D (Sigma-Aldrich South Africa) withconcentrations ranging between 05 120583gmL and 0002120583gmLThe microtitre plate was incubated for further 72 hrs andthereafter 50120583L XTT was added to a final concentration of03mgmL to one set of plates and 20120583L PrestoBlue wasadded to another set of plates The plates were incubatedfor further 2 hrs where after the absorbance of the colourcomplex was read at 490 nm with a reference wavelength setat 690 nm for XTT and at 570 nmwith a reference wavelengthset at 600 nm for PrestoBlue using a BIO-TEK Power-WaveXS multiwell plate reader

International Journal of Microbiology 3

(a) (b) (c)

(d) (e) (f)

MIC of 488 times 10minus2

120583gmLclearly observed for

PrestoBlue andAlamar Blue

No colourdistinction for

INT

clearly observed forPrestoBlue and

Alamar Blue

Deep redcolour change

MIC observed at78 times 10

minus2120583gmL MIC of 0391120583gmL

Figure 1 Comparison of different growth indicators on oral microorganisms (a) INT on S mutans (b) PrestoBlue on S mutans (c) AlamarBlue on S mutans (d) INT on P intermedia (e) PrestoBlue on P intermedia and (f) Alamar Blue on P intermedia

3 Results and Discussion

31 Determination of MIC for Microbial Strains

311 Evaluation of MIC against Oral Microorganisms Thecolour change of the growth indicators INT PrestoBlue andAlamar Blue for S mutans and P intermedia is depicted inFigure 1

The development time for each of the oral bacteriadiffered With the addition of INT P intermedia developedwithin 40 minutes however S mutans development tookover two hours and it was difficult to distinguish where theMIC occurred Conversely with PrestoBlue or Alamar BlueS mutans developed immediately and the MIC was easilydistinguishable with pink indicating viable bacteria andblue indicating nonviable bacteria P intermedia developedwithin 20 minutes although the colour change took slightlylonger with Alamar Blue The MIC values obtained for theinhibition of S mutans and P intermedia by CHX showedthe same values using both PrestoBlue and Alamar Blue at488 times 10

minus2120583gmL and 0391120583gmL respectively P interme-

dia showed a slightly higher MIC with the development ofINT (at 078120583gmL) It was almost impossible to determinetheMIC value for the inhibition of Smutansusing INTThereappeared to be a distinctive colour change for each of thebacteria whether using PrestoBlue or Alamar Blue

(a) (b)

No colour distinction for

INT

MIC clearly observed for PrestoBlue at 3125120583gmL

Figure 2 Comparison of different growth indicators on P acnes (a)INT and (b) PrestoBlue on P acnes

312 Evaluation of MIC against Propionibacterium acnesThe colour change of the growth indicators INT and Presto-Blue for P acnes were observed after addition of the reagentsas seen in Figure 2

The comparison between INT and PrestoBlue for deter-mination of MIC values for bacterial cells treated withtetracycline was clearly indicated with the use of PrestoBluewhen compared with INT The P acnes bacteria had atendency to coagulate at the bottom of the wells during the


(a) (b)

(c) (d)

Clear colour change gradient for both XTT

and PrestoBlue


and PrestoBlue

IC50 value of0006 plusmn 1 times 10

minus4120583gmL

for PrestoBlue

IC50 value of

for XTT


minus4120583gmL

for PrestoBlue


minus4120583gmL

for XTT

0005 plusmn 2 times 10minus4120583gmL

Figure 3 Comparison of different growth indicators on various cell lines (a) XTT on HeLa cells (b) PrestoBlue on HeLa cells (c) XTT onA431 cells and (d) PrestoBlue on A431 cells

incubation period and this was where the INT was reducedto the violet colour The PrestoBlue provided an advantagein that the entire well was coloured making visualisation ofMIC values easier Tetracycline treated cells in the presenceof INT showed no colour change as seen in Figure 2(a)However in the presence of PrestoBlue there was a cleardistinction between wells with metabolically active bacterialcells (pink) and those which had been inhibited (blue)by the tetracycline control drug Although the incubationperiod of the PrestoBlue plates was slightly longer (plusmn3 hrs)compared with INT (plusmn1 h) the determination of MIC valueswas much clearer The MIC of tetracycline was determinedto be 3125 120583gmL with PrestoBlue and could not be visuallydetermined with INT

313 Evaluation of MIC against Mycobacterium tuberculosisThe health risk involved in working with M tuberculosismeant no clear pictures of the colour changes could beobtained

Due to the slow growth rate of M tuberculosis the con-version of the Alamar Blue and PrestoBlue into a red colourtook up to 24 hrs Although a colour change could beobserved after 3 hrs the longer incubation period resultedin a more distinguishable separation between viable pinkbacterial wells and blue inhibited wells There were no dif-ferences observed between the MIC values of the positivecontrols when comparing Alamar Blue and PrestoBlue INHshowed anMIC of 013120583gmLwhereas Rifampicin showed anMIC of 075 120583gmL for both PrestoBlue andAlamar BlueThePrestoBlue had a slightly faster conversion rate compared to

the Alamar Blue but at 24 hr incubation the readings of theMICs were the same

32 Comparison of Growth Indicators for Cytotoxicity Analy-sis XTT and PrestoBlue were used to determine the antipro-liferative effect of ActinomycinDonHeLa cells andA431 cellsas seen in Figure 3

For both growth indicators a colour change was observedafter approximately 2 hrs Both cell lines were exposed toActinomycin D and the IC

50values were determined

The IC50

values observed when comparing XTT toPrestoBlue were similar On the HeLa cells the positivecontrol showed IC

50values of 0005 plusmn 2 times 10minus4 120583gmL and

0006 plusmn 1 times 10minus4120583gmL for XTT and PrestoBlue respectively

whereas on the A431 cells the positive control showed IC50

values of 0011 plusmn 2 times 10minus4 120583gmL for both growth indicatorsThe colour change was observed at approximately the sametime and both growth indicators showed a distinguishablecolour change

PrestoBlue showed great potential as a growth indicatorfor various microorganisms as well as a cell viability It hasminor limitations such as light sensitivity and the varied timetaken for colour development which is dependent on themetabolic rates of various bacteria and cell cultures Althoughthese are potential drawbacks the results remain conclusive

4 Conclusion

PrestoBlue and Alamar Blue give clear and easily determinedvisual MIC values for S mutans P intermedia P acnes and


M tuberculosis However S mutans P intermedia andM tuberculosis developed a colour change more rapidly inPrestoBlue than in Alamar Blue Furthermore Alamar Blueand PrestoBlue as growth indicator reagents have an advan-tage over other reagents such as INT in that the whole assaywell changes colour instead of only the bacteria ThereforePrestoBlue may be the better indicator for these microorgan-isms

Comparing the reagents XTT and PrestoBlue as cell via-bility indicators it was observed that both growth indicatorsshowed clear distinction between viable cells and nonviablecells and the IC

50values obtained from both reagents were

similar

References

[1] Invitrogen ldquoPrestoBlue cell viability reagent protocolrdquo Productinformation sheet by Life Technologies 2012 httptoolsinvitrogencomcontentsfsmanualsPrestoBlue Reagent PIS15Oct10pdf

[2] M V Berridge A S Tan K D Mccoy and R Wang ldquoThebiochemical and cellular basis of cell proliferation assays thatuse tetrazolium saltsrdquo Biochemica vol 4 pp 14ndash19 1996

[3] J MacFarland ldquoThe nephelometer an instrument for estimat-ing the number of bacteria in suspensions for calculating theopsonic index and for vaccinesrdquo Journal of America MedicalAssociation vol 49 pp 1176ndash1178 1907

[4] J Pannu A McCarthy A Martin et al ldquoIn vitro susceptibilityof P acnes and skin permeation of NB-00X formulationsrdquoAnti-microbials and Chemotherapy vol 55 no 9 pp 4211ndash4217 2011

[5] J N Eloff ldquoA sensitive and quick microplate method to deter-mine the minimal inhibitory concentration of plant extracts forbacteriardquo Planta Medica vol 64 no 8 pp 711ndash713 1998

[6] M A Cohen M D Huband S L Yoder J W Gage and GE Roland ldquoBacterial eradication by clinafloxacin CI-990 andciprofloxacin employingMBC test in-vitro time-kill and in-vivotime-kill studiesrdquo Journal of Antimicrobial Chemotherapy vol41 no 6 pp 605ndash614 1998

[7] S G Franzblau R SWitzig J CMclaughlin et al ldquoRapid low-technology MIC determination with clinical Mycobacteriumtuberculosis isolates by using the microplate Alamar Blue assayrdquoJournal of ClinicalMicrobiology vol 36 no 2 pp 362ndash366 1998

[8] Y T Zheng W L Chan P Chan H Huang and S C TamldquoEnhancement of the anti-herpetic effect of trichosanthin byacyclovir and interferonrdquo FEBS Letters vol 496 no 2-3 pp139ndash142 2001

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from Invitrogen Corporation San Diego USA XTT cell pro-liferation Kit II was obtained from Roche Applied SciencesSouth Africa The cell culture medium trypsin-EDTA fetalbovine serum (FBS) phosphate buffer saline (PBS) andantibiotics were supplied by Highveld Biological (Pty) Ltd(Modderfontein Johannesburg RSA) All other reagentswere of analytical grade

22 Determination of the Minimum Inhibitory Concentration(MIC) for the Microbial Strains

221 Culturing ofMicroorganisms Themicroorganisms usedin this study included Prevotella intermedia (ATCC 25611)Streptococcus mutans (ATCC 25175) and Propionibacteriumacnes (ATCC 11827) S mutans and P intermedia were grownon Casein-peptone Soymeal-peptone Agar medium (CASO)enriched with 1 sucrose (Merck Chemicals (Pty) LtdWadeville South Africa) under anaerobic conditions in ananaerobic jar with Anaerocult A (Merck KGaA DarmstadtGermany) at 37∘C for 48 hrs Subculturing was done everysecond week Inoculants were prepared by suspending bacte-rial test organisms in quarter strength sterile Ringer solution(Merck KGaA Darmstadt Germany) until turbidity wascompatible with McFarland Standard 1 (Merck Chemicals(Pty) Ltd Wadeville South Africa) Furthermore a bacterialconcentration of 4 times 108 (colony forming units) CFUmL forP intermedia and 3 times 108 CFUmL for S mutans was used[3]

P acnes was cultured on Tryptone Soy Agar (MerckChemicals (Pty) Ltd Wadeville South Africa) under anaer-obic conditions in an anaerobic jar with Anaerocult A at37∘C for 72 hrs Subculturing was done every 4th week asthe doubling time of the bacterium is slow Inoculants wereprepared by suspending the bacterial colonies in NutrientBroth (Merck Chemicals (Pty) Ltd Wadeville South Africa)until turbidity was compatible with aMcFarland Standard 05at a bacterial concentration of 15 times 108 CFUmL [4]

222 Evaluation of MIC Values for Microorganisms Themicrodilution technique using 96-well microtitre plates asdescribed by Eloff [5] was used to obtain the MIC valuesof the positive drug controls against the various microor-ganisms The positive controls for oral bacteria chlorhexi-dine gluconate (CHX) (Dental Warehouse Sandton SouthAfrica) at 125 120583gmL and Tetracycline (Sigma-Aldrich 3050Spruce Street St Louis) at 200120583gmL for P acnes wereserially diluted in relevant broth medium adding 48 h oldoral bacteria and 72 h old P acnes and were incubated at37∘C in anaerobic conditions The final concentration ofCHX ranged 313120583gmLndash244times10minus2 120583gmL and Tetracyclineranged 100 120583gmLndash0781120583gmL S mutans and P interme-dia were incubated for 24 hrs and P acnes for 72 hrs at37∘C

To indicate bacterial growth 40120583L of (02mgmL) INT20120583LPrestoBlue and 20 120583LAlamarBluewas added tomicro-plate wells and reincubated until a colour change occurredThe MIC was defined as the lowest concentration thatinhibited the growth of the bacteria [6]

223 Evaluation of MIC against Mycobacterium tuberculosisFor the antimycobacterial assay the H37Rv (ATCC 27264)M tuberculosis strain was used The bacteria were culturedon Lowenstein-Jensen (LJ) medium (SA Medical ResearchCouncil Pretoria) for three weeks (37∘C 5 CO

2) One

colony was transferred under sterile conditions to 50mL of7H9 broth media (Sigma-Aldrich South Africa) 10 OADC(Sigma-Aldrich South Africa) and 2 PANTA (BectonDickinson and Company USA) The bacteria were furthercultured for one week After the final incubation period thebacteria were adjusted in 7H9 broth media to a turbidity ofa McFarland Standard 1 Bacterial suspensions were furtherdiluted 1 25 to obtain a concentration of 2times108 CFUmL [7]

TheMicrotitreAlamarBlue assay (MABA) andMicrotitrePrestoBlue assay (MPBA) were used to determine the MICof positive drug controls on the bacteria [7] Standard anti-tuberculosis agents INH (Sigma-Aldrich Becton Dickinsonand Company) and RIF (Sigma-Aldrich Becton Dickinsonand Company) were used Stock solutions were diluted in7H9 brothmedia to a final assay concentrationswhich ranged5 120583gmLndash0078120583gmL and 6 120583gmLndash01875120583gmL for INHand RIF respectively A 2 dimethyl sulfoxide (DMSO)solvent control media control and bacterial control wasincluded in the assay One hundred microlitres of bacteriawas added to the inner wells of the 96-well plates The outerperimeter wells were used to compensate for evaporationby adding 200120583L of dH

2O The plates were incubated for

5 to 7 days at 37∘C 5 CO2 After 5 days 20120583L of Alamar

BluePrestoBlue indicator solution was added to one of thebacterial control wells If a colour change was observed allthe subsequent wells received 20120583L of indicator solution Ifno colour change was observed the plates were incubated forfurther 24 hrs

23 Comparison of Growth Indicators for Cytotoxicity Analy-sis The HeLa and A431 cell lines were maintained in EaglersquosMinimum Essential Medium supplemented with 10 FBSand 1 antibiotics (100UmL penicillin 100 120583gmL strepto-mycin) and 250 120583gmL fungizone The cells were grown at37∘C in a humidified incubator set at 5 CO

2 Cells were

subcultured by treating them with trypsin-EDTA (025trypsin containing 001 EDTA) for 10 minutes

Cytotoxicity was measured using the XTT cell prolifer-ation Kit II and MPBA The method described by Zhenget al [8] was used to perform the assay Both cell lines wereseeded in a 96-well microtitre plate at a concentration of1 times 10

5 cellsmL Cells were allowed to attach for 24 hrs at37∘C and 5CO

2The cells were exposed to the positive drug

control Actinomycin D (Sigma-Aldrich South Africa) withconcentrations ranging between 05 120583gmL and 0002120583gmLThe microtitre plate was incubated for further 72 hrs andthereafter 50120583L XTT was added to a final concentration of03mgmL to one set of plates and 20120583L PrestoBlue wasadded to another set of plates The plates were incubatedfor further 2 hrs where after the absorbance of the colourcomplex was read at 490 nm with a reference wavelength setat 690 nm for XTT and at 570 nmwith a reference wavelengthset at 600 nm for PrestoBlue using a BIO-TEK Power-WaveXS multiwell plate reader


(a) (b) (c)

(d) (e) (f)





INT


Alamar Blue











(a) (b)


INT






(a) (b)

(c) (d)


and PrestoBlue


and PrestoBlue


minus4120583gmL

for PrestoBlue

IC50 value of

for XTT


minus4120583gmL

for PrestoBlue


minus4120583gmL

for XTT










The IC50







4 Conclusion






similar

References
















Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology


(a) (b) (c)

(d) (e) (f)





INT


Alamar Blue











(a) (b)


INT






(a) (b)

(c) (d)


and PrestoBlue


and PrestoBlue


minus4120583gmL

for PrestoBlue

IC50 value of

for XTT


minus4120583gmL

for PrestoBlue


minus4120583gmL

for XTT










The IC50







4 Conclusion






similar

References
















Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology


(a) (b)

(c) (d)


and PrestoBlue


and PrestoBlue


minus4120583gmL

for PrestoBlue

IC50 value of

for XTT


minus4120583gmL

for PrestoBlue


minus4120583gmL

for XTT










The IC50







4 Conclusion






similar

References
















Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology





similar

References
















Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology








Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology

Documents

Research Article Viability Reagent, PrestoBlue, in ...downloads.hindawi.com/journals/ijmicro/2013/420601.pdf · of the positive drug controls against the various microor-ganisms