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  1. May 2019
    1. Typically 200-300 ng of DNA was used in each ligation reaction. The ratio of vector toinsert was maintained between 1:3 to 1:5 for cohesive end ligation and 1:1 for blunt endligation. The reaction was generally performed in 10 μl volume containing ligationbuffer (provided by the manufacturer) and 0.05 Weiss unit of T4-DNA ligase, at 16ºCfor 14-to 16-hrs. On using the rapid ligation kitfrom Fermentas, incubation was at 22ºC for 1-2 hrs
    2. PCR products were purified using the PCR Purification Kit (Qiagen) as per the manufacturer's instructions
    3. DNA fragments to be used for specific purposes like ligation or radioactive labeling were eluted from the agarose gel after electrophoresis. The gel piece containing thedesired band was sliced out from the gel and the DNA was purified using commerciallyavailable purification kits for this purpose. The efficiency of elution was determined bychecking a small aliquot of DNA sample on the gel
    4. Purification of DNA by gel elution
    5. Around 0.5 to 1 μg of DNA was regularly used for each restriction digestion. 2to 5units of restriction enzyme were used in the total reaction volume of 20 μl containing 2μl of the corresponding buffer supplied at 10 X concentration by the manufacturer. Thereaction was incubated for 2 hrs at the temperature recommended by the manufacturer.The DNA fragments were visualised by ethidium bromide staining after electrophoresison a 0.8 to 1% agarose gels. Commercially available DNA size markers were run alongwith the digestion samples to compare with and to estimate the sizes of the restrictionfragments
    6. Restriction enzyme digestion and analysis
    7. TheDNA samples were mixed with appropriate volumes of 6 X loading dye (0.25%bromophenol blue and 0.25% xylene cyanol and 30% glycerol in water) and subjectedto electrophoresis through 0.8 to 1 % agarose gel in TAE buffer. The gel was stained in1 μg/ml ethidium bromide solution for 15-min at room temperature and visualised byfluorescence under UV-light in a UV-transilluminator
    8. werethen recovered by centrifugation at 12,000 rpm for 30-min. The pellet was washed oncewith 70% ethanol, air-dried and re-suspended in 100 μl of TE-buffer. It was treatedwith RNase at a concentration of 20 μg/ml by incubating at 37ºC for 1-hr. It was furtherextracted with an equal volume of phenol:chloroform mixture followed bychloroform:isoamyl alcohol (24:1) mixture. After centrifugation, the clear supernatantwas used for recovering the nucleic acids. The nucleic acids were precipitated with 200μl of alcohol in presence of 0.3 M sodium acetate (Sambrook and Russell, 2001). In casewhere high purity plasmid preparations are required (DNA sequencing) the plasmidisolation was carried out with the commercially available kits following themanufacturer’s instruction. Plasmids were observed on 1% agarose gel
    9. 1.5 ml of stationary phase culture wascentrifuged and cell pellet was re-suspended in 567 μl of TE buffer. To this 30 μl of10% SDS, and 3 μl of proteinase K (20 mg/ml) were added in that order and the cellsuspension was mixed and incubated at 37ºC for 1-hr. When the suspension was clear, 100 μl of 5 M NaCl was added and thoroughly mixed followed by the addition of 80 μlCTAB/NaCl (10% cetyl trimethyl ammonium bromide in 7 M NaCl). The suspensionwas incubated at 65ºC for 10-min, brought to room temperature and extracted with anequal volume (780 μl) of chloroform isoamyl alcohol (24:1), and aqueous phasetransferred to fresh tube. The aqueous phase was further extracted successively, firstwith phenol:chloroform:isoamyl alcohol (25:24:1) and then with chloroform isoamylalcohol (24:1). DNA was precipitated fromthe clear supernatant by the addition of 0.6volumes of iso-propanol. The chromosomal DNA was either spooled out or pelleted atthis stage and washed with 70% ethanol air dried and dissolved in 100 μl of TE-buffer
    10. 1.5 ml of cells from an overnight culture waspelleted by centrifuging in cold (4ºC) for10-min at 6000 rpm. The cells were re-suspended in 200 μl solution I (50 mM glucose; 25 mM Tris-Cl, pH-8; 10 mM EDTA, pH-8) with vortexing. 400 μl of freshly preparedsolution II (0.2% NaOH, 1% SDS) was added and mixed by gently inverting the tubes.Subsequently, 300 μl of solution III (prepared by mixing 60 ml of 5 M CH3COOK,11.5 ml glacial acetic acid, 28 ml water) was added and the tubes were invertedrepeatedly and gently for homogeneous mixing followed by incubation for 5-min onice. After centrifuging at 12,000 rpm for 15-min, supernatant wasdecanted into a freshtube, an equal volume of iso-propanol was added, the precipitated nucleic acids
    11. A differential gene expression microarray with respect to argP was performed by Genotypic Technology Pvt.Ltd., Bengaluru. The experiment was performed on an oligonucleotide microarray having 10828 probes for coding region(on average three probes were designed for each 4294 coding regions) and 4380 probes for non-coding region (on average two probes were designed for 2240 non-coding regions). The RNA was labelled using Cy3 and single channel detection was used. Data was analysed using GeneSpring GX Version 7.3
    12. supplemented with amino acids and appropriate antibiotic and grown at 37ºC to an A600of 0.5-0.6. Around 0.1-0.5 ml of culture was made up to 1 ml with Z-buffer and lysedwith addition of one drop of chloroform and 1-2 drops of 1% SDS solution. 0.2 ml offreshly prepared 4 mg/ml ONPG was added to start the reaction and incubated at roomtemperature till the color of the reaction mixture turned yellow. 0.5 ml of 1 M Na2CO3was added to stop the reaction and the time duration from initial addition of ONPG tothe stopping of reaction was noted.The absorbance of reaction mix was taken at 420nm and 550 nm. The A600of the culture used was also noted. The enzyme specificactivity (in Miller units) was calculated using following equation:β-galactosidase specific activity = [1000 X A420-(1.75 X A550)] / t X v X A600Where t isthe time period in minsand v the volume of culture used in ml.Each value reported is the average of at least three independent experiments, and the standard error was <10% ofthe mean in all cases
    13. β-galactosidase assay was performed according to Miller (1992). An overnight grownculture of the bacterial strain was sub-cultured in glucose Minimal A medium
    14. Thialysine or thiosine (S-Aminoethyl-L-cysteine)is a toxic analog of Lys. Strains were testedfor sensitivity/resistance to thialysine by streaking them on minimal A-glucose platessupplemented without and with100-200 μg/ml thialysine(Steffes et al., 1992)
    15. For testing ArgR+/–phenotype, the colonies werestreaked on minimal A-glucose plates containing uracil (40 μg/ml) and CAN(65 μg/ml). Uracil wasadded to the medium to sensitize an argR+strain to CAN. An argR+strain is inhibited at65 μg/ml CANon a uracil-containing plate, whereas on a plate without uracil, argR+would grow even at 700-800 μg/ml CAN. Uracil represses the carAB transcription, whichencodes the carbamoyl phosphate synthase enzyme (CarAB). This results in reducedamounts of carbamoyl phosphate, which is the common intermediate between pyrimidineand Arg biosynthetic pathways. Reduced carbamoyl phosphate levels would result indecreased flux through the Arg biosynthetic pathways. This in turn would result indecrease in Arg pools inside the cell. An argR mutant would be derepressed for the Argbiosynthetic pathway and is resistant even to 300 μg/ml CANin a uracil-containing plate
    16. CAN is a toxic analog of Arg and is an inhibitor of bacterial growth. Strains were tested for sensitivity/resistance to CAN by streaking them on minimal A-glucose platessupplemented withoutand with40 μg/ml CAN(or other concentrations as indicated) and 40 μg/ml uracil
    17. The colonies to be tested were streaked on the surface of minimal A-glucose plates containing either 0.4-0.7 M NaCl with 1 mM glycine betaine, and incubated at 37oC. NaCl-tolerant strains grew toform single colonies in 36-60 hrs whereas NaCl-sensitive ones did not. As controls, MC4100 (WT) and other previously identified NaCl sensitive mutants were streakedfor comparison
    18. NaCl-sensitivity testing
    19. agar platesLac+colonies will appear dark pink colonies whereas Lac–will remain colourless
    20. Competent cells for high efficiency transformations were prepared by a method ofInoue et al. (1990) with few modifications. An overnight culture of the strain (routinelyDH5α) was sub-cultured into fresh sterile LB-brothin 1:100 dilutions and grown at 18ºC to an A600of 0.55. The cells were harvested by centrifugation at 2500 rpm for 10-min at 4ºC. This was re-suspended in 0.4 volumes of INOUE buffer and incubated inice for 10 min. The cells were recovered by centrifugation at 2500 rpm at 4ºC for 10-min and finally re-suspended in 0.01 volume of the same buffer. Sterile DMSO wasadded to a final concentration of 7%. After incubating for 10-min in ice, the cells werealiquoted in 100 μl volumes, snap frozen in liquid nitrogen and stored at –70ºC
    21. For routine plasmid transformations, following method which is modification of thatdescribed by Cohen et al. (1972) was used. An overnight culture of recipient strain wassub-cultured 1:100 in fresh LB medium and grown till mid-exponential phage. Theculture was chilled on ice for 15-min, and the steps thereafter were performed at 4ºC.20 ml of culture was centrifuged and pellet was re-suspended in 10 ml of 0.1 M CaCl2.After 15-min of incubation on ice, the cells were again centrifuged and re-suspended in2 ml of 0.1 M CaCl2. The suspension was incubated on ice for 30-min. To the 200 μl aliquot of the cell suspensionplasmid DNA (20 to 200 ng in less than 10 μl volume)was added, incubated for half an hron ice and given a heat shock for 90-sec at 41ºC.The cultures was rapidly chilled, mixed with 0.8 ml of LB-broth and incubated at 37ºCfor 1-hr, and plated on an appropriate selective medium at various dilutions. An aliquotof cell suspension to which plasmid DNA was not added served as a negative control
    22. the infection mixture was centrifuged, washed in 5 ml of citratebuffer and plated without phenotypic expression
    23. To 2 ml of fresh overnight culture of recipient strain, 108pfu equivalent of phage lysatewas added and incubated at 37ºC without shaking for 15-min to facilitate phageadsorption. The un-adsorbed phage particles were removed by centrifugation at 4000rpm for 5-min and pellet of bacterial cells was re-suspended in 5 ml of LB-brothcontaining 20 mM sodium citrate to prevent further phage adsorption. This wasincubated for 30-min at 37ºC without shaking to allow the phenotypic expression of theantibiotic resistance gene. The mixture was then centrifuged, and the pellet was resuspendedin 0.3 ml citrate buffer. 100 μl aliquots were plated on appropriate antibioticcontaining plates supplemented with 2.5 mM sodium citrate. A control tube withoutaddition of P1 lysate was also processed in the same way. In the case of selection ofnutritional requirement,
    24. 0.3 ml of overnight culture of the donor strain in Z-broth was mixed with 107plaqueforming units (pfu) of a stock P1 lysate prepared on strain MG1655. Adsorption wasallowed to occur at 37ºC for 20-mins. To 0.3 ml of infectionmixture, 10 ml of Z-broth was added and incubated at 37ºC withslow shaking until the visible lysis of the culture occurred (in 4-6 hrs). The lysate wastreated with 0.3 ml of chloroform, centrifuged and the clear lysate was stored at 4ºCwith chloroform.Preparation of P1 lysates on recA mutant strains were also donesimilarly, but with a higher multiplicity of infection (i.e. 108starter P1 phage).To quantitate the P1 phage lysate preparation, titration was done using P1 phagesensitive indicator strainsuch as MG1655. 100 μl each of dilution of phage (typically10–5, 10–6) were mixed with 0.1 ml of fresh culture grown in Z-broth. After 15-min ofadsorption at 37ºC without shaking, each mixture was added on a soft agar overlay ofZ-agar plates and incubated overnight at 37ºC. The phage titer was calculated from thenumber of plaques obtained on the plates
    25. purification of DNA fragments werefrom Qiagen or HiMedia. The oligonucleotide primers used in this study were mainly synthesised by Ocimum Biosolutions or MWG Biotech. The radioactive chemicals were procured from BRIT Mumbai
    26. Chemicals were obtained from commercial sources. Most of the chemicals such as amino acids, antibiotics, sugars, IPTG, ONPG and X-gal were obtained from Sigma Chemical Co. The media components for the growth of bacteria were mostly from HiMedia laboratories. The materials used in the recombinant DNA experiments such as restriction endonucleases, T4-DNA ligase, DNA-polymerases and DNA size markers were obtained from companies including New England Biolabs, MBI Fermentas and Stratagene.RNA isolation chemicals like Reverse transcriptase, trizol, RNA loading buffers and dyes and RNA size markers were obtained from Invitrogen and Sigma. Protein markers were obtained from MBI Fermentas. Kits for plasmid isolation,
    27. Antibiotics were used at the following final concentrations in various media as given inTable 2.4.Table 2.4Concentrations of antibiotics (μg/ml)
    28. Waterto 3 mlTEMED 10 μlDenaturing (urea) sequencing gel (6%) composition10 X TBE 50 ml40% acrylamide 75 mlUrea 210 gm (7 M)Waterto 500 mlThis was filtered through a 0.45/0.22 μ milipore filter.For casting the gel 35 ml of the sequencing gel mixure was mixed with 150 μl10% APS and 25 μlTEMED
    29. Formaldehyde agarose gel(For 50 ml)DEPC treated water 43 mlMOPS buffer 5.3 mlAgarose0.63 gmFormaldehyde2.6 mlThe above mix was boiled without formaldehyde to dissolve agarose and then at around 50ºC formaldehyde was added just before casting the gel.40% Acrylamide solutionAcrylamide39 gmBis-acrylamide 1 gmWater to 100 mlNon denaturing gel composition (50 ml)40% acrylamide solution 5 ml10 X TBE 5 mlH2O 40 ml10% APS 250 μlTEMED 30 μlSDS PAGE gel (12%)For resolving Gel (15 ml):30% Acrylamide solution 6 ml1.5 M Tris-Cl (pH 8.8)3.8 ml10% SDS150 μl10% APS 150μlWaterto 15 mlTEMED 10 μlFor stacking gel (3 ml):30% Acrylamide solution 500 μl1 M Tris Cl (pH 6.8) 380 μl10% SDS 30 μl10% APS 30 μl
    30. Storage buffer for proteinTris-Cl (pH 8.0) 20 mMNaCl 300 mMDTT10 mMGlycerol 40 % Hybridization bufferTris-Cl (pH 8.0) 9 mMEDTA 0.35 mMSample buffer (for SDS-PAGE)Tris-Cl (pH 6.8) 150 mMSDS (20%) 6% v/vGlycerol 30% v/vβ-mercaptoethanol (5%) 15%Bromophenol blue 0.6% (w/v)EMSA binding bufferTris-Cl (pH 7.5) 10 mMNaCl 50 mMEDTA1 mMGlycerol 5 %DTT 5 mMDenaturing gel loading buffer with dyeFormamide 95%EDTA 20 mMXylene Cyanol 0.05 gmBromophenol blue0.05 gmNon denaturing gel loading buffer with dyeTris-Cl (pH 7.5) 250 mMBromophenol blue 0.02%Glycerol 20%
    31. MOPS bufferMOPS 4.16 gm0.5 M EDTA 1.0 mlSodium acetate 0.68 gmWater (nuclease free) to 500 mlIt was filter sterilized and stored in an amber colored bottle. This was prepared as 10 Xstock solution and used at 1 X concentration.INOUE (PIPES) bufferPIPES (free acid) 10 mMCaCl2.2H2O15 mMKCl 250 mMMnCl2.4H2O 55 mMpH was adjusted to 6.7 with 1 N KOH.PIPES gets into solution when the pH is greater than 6.7. MnCl2was dissolvedseparately and added drop by drop with stirring. The pH was adjusted to 6.7 and filtersterilized and stored at –20ºC.Z buffer (for β-Galactosidase assay)Na2HPO416.1 gmNaH2PO45.5 gmKCl0.75 gmMgSO4.7H2O 0.246 gmβ-mercaptoethanol 2.7 mlWaterto 1000 mlpH was adjusted to 7.0 and stored at 4ºC.SDS running bufferTris-base 30.3 gmGlycine144 gmSDS 10 gmWaterto 1000 mlIt was prepared in 10 X concentration and diluted to 1 X for running
    32. Citrate bufferCitric acid (0.1 M)4.7 volumeSodium citrate (0.1 M) 15.4 volumeTE bufferTris-Cl (pH 8.0) 10 mMEDTA 1 mMTBE bufferTris-Borate 90 mMTris-Borate 90 mMEDTA (pH 8.0) 2 mMThis was prepared as 10 X stock solution and used at 1 X concentration.TAE bufferTris-acetate 40 mMEDTA (pH 8.0) 2 mMThis was prepared at 50 X concentrated stock solution. Both TBE and TAE were usedas standard electrophoresis buffers
    33. LB agarLB medium 1000 mlBacto-agar 15 gmZ broth (for P1 transduction)LB medium100 mlCaCl2(0.5 M) 0.5 mlZ agar (for P1 transduction)Z broth 100 mlBacto-agar0.75 gm
    34. Amino acids when required, were added to a final concentration of 40 μg/ml. Whengrowth on other carbon sources was to be tested, glucose was substituted withappropriate sugar at 0.2%.Glucose-minimal A medium, pH 7.4This medium was same as Glucose-minimal A medium described above except for the difference in K2HPO4and KH2PO4which were as mentioned below:K2HPO414.0 gmKH2PO42.7 gmGlucose-minimal A medium, pH 5.8This medium was same as Glucose-minimal A medium described above except for the difference in K2HPO4andKH2PO4which wereas mentioned below:K2HPO41.5 gmKH2PO412.4 gmGlucose /Glycerol-minimal A 19 (18 or 17) amino acidmediumThis medium is essentially the same as glucose/glycerol-minimal A medium described above except that all 19 or 18 or 17 otherthan either Lys or Lys and Arg or Lys and Arg and His amino acids were added after autoclaving at a final concentration of 40μg/ml from autoclaved 4 mg/ml stock solutions.Minimal A agarIt contains 1.5% bacto-agar (Difco) in minimal A medium. The plates were pouredafter mixing double strength minimal A with 3% agarthat had been autoclaved separately.LB mediumTryptone 10.0 gmYeast Extract5.0 gmNaCl 10.0 gmWaterto1000 mlpH adjusted to 7.0 to 7.2 with 1 N NaOH
    35. All media and buffers were sterilised by autoclaving at 121ºC for 15 mins. Mediaand buffers used in this study are given below:Glucose /Glycerol-minimal A mediumK2HPO410.5 gmKH2PO44.5 gm(NH4)2SO41.0 gmSodium citrate, 2H200.5 gmWater to 1000mlAfter autoclaving the following solutions were addedMgSO4(1M) 1 mlGlucose (20%) 10 mlOr Glycerol (80%)5 mlVitamin B1 (1%) 0.1 ml
    36. The primers used in this study are listed in Table 2.3.Table 2.3 Oligonucleotide primersa
    37. bindingsite lie upstream of the MCS to ensure the high level expression of any genecloned in MCS. A stretch of hexa-histidine (His6)-encoding codons followed by stopcodon is incorporated downstream of MCS to give a C-terminally His6-taggedrecombinant protein (EMD Biosciences).6. pBAD18:It is an expression vector with a pMB9derived origin of replication and allows for tightly regulated expression of genes cloned under the PBADpromoter of the araBADoperon (Guzman et al.,1995). The vector also carries thearaCgene, encoding the positive and negative regulator of this promoter.7. pCP20: pSC101-based Ts replicon, chloramphenicol resistant, ampicillin resistant, for in vivoexpression of Flp recombinase (Datsenko and Wanner, 2000)Plasmid DNA preparations were routinely made from recAstrainDH5αandwerestored in 10 mM Tris-Cl (pH-8.0) with 1 mM EDTA at –20ºC. The plasmid constructsused in this study are given in Table 2.2.Table 2.2Plasmid constructs
    38. The plasmid vectors used in this study were as follows:1.pCU22: It is a derivative of pUC19 used to prepare supercoiled DNA for in vitrotranscription where two strong phage fdtranscription terminators flank MCS. This ensures that the transcripts originated from vector based promoters will not interferewith the transcription from the cloned promoter and that the transcript originated fromthe cloned promoter will be terminated after the MCS (Ueguchi and Mizuno,1993).2.pMU575: It is an IncW-based, single-copy, trimethoprim resistance bearingpromoter probe vector. It carries its MCS upstream of a promoterless galK’-lacZfusion. This fusion has the first 58 codons of galKfused to the 8th codon oflacZ, andthe resultant hybrid polypeptide possesses functional β-Galactosidase activity(afterassembly as a tetramer). Translation of the hybrid gene is controlled by the ribosomebinding site of galK. There are stop codons in all the three reading frames between MCS and initiation codon of galKso that there is no interference caused bytranslational read-through from inserts cloned into MCS region. A strong pheRterminator located upstream of the MCS prevents read through from any vector-basedpromoter into the lacZgene (Andrews et al.,1991).3. pTrc99A:It is an expression vector with ColE1 origin of replication and ampicillin resistance marker. It provides IPTG dependent induction of the cloned gene (Amann et al., 1988)4. pCL1920: It is a pSC101-based, low-copy-number vector with spectinomycin and streptomycin resistance marker carrying the MCS in lacZαregion and henceprovides the advantage of screening the insertions using α-complementation (Lernerand Inouye,1990).5. pET21b: It is a ColE1-based, high-copy-number expression vector bearing ampicillinresistance marker. A strong T7 RNAP-recognised promoter and an efficient ribosome
    39. TheE. coli strains used in this study with their genotypes are shown in Table 2.1. All strains other than BL21 (DE3) employed in protein overexpression experiments are derivatives of E. coli K12. Bacterial strains were routinely stored on solid agar plates at 4ºC and also as thick suspensions in 40% glycerol at –70ºC. Plasmid harboring strains were freshly prepared by transformation of the required plasmid. The bacteriophage P1kc from the laboratory collectionwas used for routine transduction tomove a locus from one strain to anotherand is referred to as P1 throughout this thesis.Table 2.1 E. coli strains used in this study
    1. For TEM, C. glabrata cells were digested with zymolyase 20T for 3 h at 30◦C, centrifuged at 1,000 g and washed with YPD medium. Cell fixation was performed as described for SEM and dehydrated samples were embedded in araldite 6005 resin. After complete polymerization at 80 ̊C for 72 h, ultra-thin (50-70 nm) sections were preparedwith a glass knife on Leica Ultra cut (UCT-GA-D/E-1/00)microtomeand mounted on copper grids. Aqueous uranyl acetate-stained and Reynolds lead citrate-counterstained samples were viewed under Hitachi H-7500 transmission electron microscope
    2. For SEM, C. glabratacells were fixed for 24 h in 2.5% glutaraldehyde in phosphate buffer (0.1 M, pH 7.2) at 4 ̊C, post-fixed in 2% aqueous osmium tetroxide for 4 h and dehydrated. After drying to critical point, mounted samples were coated with a thin layer of gold for 3 min using an automated sputter coater and visualized by SEM (JEOL-JSM 5600)
    3. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were performed at the Electron Microscope Facility, RUSKA LABs, Acharya N. G. Ranga Agricultural University, Hyderabad
    4. Log-phase yeastcells were collected, washed and suspendedin 10 mM Tris-HCl (pH 7.5) containing 50 mg/ml zymolyase-20T. Cell suspension was incubated at room temperature and absorbance was monitored at 600 nm every10mininterval. Initial absorbance of the cultures at 0 minwas normalized to 100%and the graph was plottedas%decrease in the absorbance with respect to time
    5. Resultant precipitate was dissolved in 3 N HCl and reprecipitated in methanol:acetic acid (8:1) solution. Following 16 h incubation at room temperature, the precipitate was washed withmethanol:acetic acid (8:1) solution till green colour of the supernatant disappeared.Finally,pellet was washed thrice with methanol and air dried. Driedpellet was resuspended in 0.5 NHCl and total mannan content was quantified with phenol-sulphuric acid carbohydrate estimation method as described earlier.Commercially available purified glucose was used as the standard
    6. Total mannan from 3% NaOH-extractable supernatant of cell wall was precipitated by Benedict’s solution.Reducing sugars(mostly mannan) from alkali-extractable supernatant reactwith copper(II) sulphate present in Benedict’s solution and forms red copper(I) oxide precipitate.Briefly, equal volume of Benedict’s solution was added to 3% NaOH-extractable cell wall supernatant fraction and heated at 99 ̊C for 10 min
    7. Cell wall β-glucan measurement was carried out as describedpreviously with some modifications(Kapteynet.al.,2001). Briefly, cell wall fractions were washed multiple times with 1 N NaCl. Washed cell walls were boiled twice in 50 mM Tris-HCl(pH 7.8) containing 2% SDS, 100 mM Na-EDTA and 40 mM β-mercaptoethanol for 5 min to remove non-covalently linked proteins and other contaminants. SDS-treated cell wall fraction was collected and rinsed thrice with water. For β-glucan isolation, cell wallswere extracted three times, each for 1 h, in 0.5 ml 3% NaOH at 75 ̊C and centrifuged at 1,200 g.All 3% NaOH supernatant fractions were saved for isolation of mannan as described below. 3% NaOH-extractable cell wall pelletwasneutralized twice in 100 mM Tris-HCl (pH 7.5) and once in 10 mM Tris-HCl (pH 7.5) and digested with 5 mg/ml zymolyase-20T in 10 mM Tris-HCl (pH 7.5) for 14-16 h at 37 ̊C. This treatment liberates approximately 90-95% glucose into the supernatant. Total glucan content in the cell wall was measured by estimating glucose from both the solubilised supernatant and zymolyase-20T insoluble pellet fractions with phenol-sulphuric acid carbohydrate estimation method using purified glucose as the standard
    8. Yeast cell wall was isolatedas describedpreviously(De Groot et al., 2004). Briefly, cells grown underdifferent environmental conditions were harvested at 5,000 g for 5
    9. Cells grown to log-phase in YPD medium were spotted on CAAmedium and overlaid with a nitrocellulose filter. Cells were allowed to grow at 30 ̊C for 18-20 h. After incubation, the filter was washed with water to remove cells and membrane-bound CPY was detected by immunoblotting withpolyclonal anti-CPY antibody (Thermo Scientific) at a dilution of 1:15,000
    10. CPY activity was measured as described previously (Jones,2002). A 2.5 mg/ml stock solution of CPY-specific substrate N-benzoyl-L-tyrosine p-nitroanilide(BTPNA, prepared in dimethyl formamide) was diluted 5 times with 0.1 M Tris-HCl (pH 7.5). 100 μl diluted substrate solution was added to a 96-well plate containing 25 μl cell suspension (5 x 107cells). After 18 h of incubation at 37 ̊C, plate contents were clarified by centrifugation and colour formation was quantified by absorbance at 405 nm. Background absorbance measured using BTPNA-free cell cultures was subtracted from BTPNA-loaded cell cultures and absorbancevalues were normalized to total number of viable cells to enumerate total cellular CPY activity
    11. ammonium molybdate, respectively, to the assay buffer.For specific inhibition of vacuolar membrane H+-ATPaseactivity, vacuolar membrane fractions were incubatedwith 1-2.5 μM bafilomycin for 5 minprior to the activity assay.ATPase activity was initiatedby adding ATP to the assay buffer to afinal concentration of 5 mM and incubating the reactionat 30 ̊C for 30-60 min.Reaction was stopped by adding an equal volumeof a stop-developing solution (1% (w/v)SDS, 0.6 M H2SO4, 1.2%(w/v)ammonium molybdate and 1.6%(w/v)ascorbic acid). Amount of inorganic phosphate (Pi) liberated was measured at A750nmafter 10 minincubation at room temperature. Standard curve prepared with 0-50 micromoles of KH2PO4 was used for the determination of total Pi. The ATPase activity of the vacuolarmembrane H+-ATPase was expressed in micromoles of Pireleased per milligram protein per min
    12. Vacuolar membrane H+-ATPase activitywas measured inbothcrude membrane fraction and purifiedvacuolar membrane fraction asdescribed previously(Woolfordet al.,1990).Activity inthe crude membrane fractions was carried out with 2.5-10 μgprotein in 50 μl assay buffer (5 mM MgCl2, 25 mM MES/Tris-HCl(pH 6.9)and 25 mM KCl). For activity inthe purified vacuolar membrane fraction, a totalof300 μl reactionmix was setup with of 2.5-10 μgprotein samples.Residual activities from other ATPases such as mitochondrial ATPases, plasma membrane H+-ATPase and phosphataseswere inhibited by adding 2 mM NaN3, 200 μM NaVO4and 0.2 mM
    13. Vacuole membraneswere isolatedwith slight modifications of Cabrera’s method(Cabrera et.al.,2008). Log-phase, YPD medium-grown cells wereinoculated in 1 lt YPDmedium to an initialOD600of 0.1. Cells were incubated at 30 ̊C with shaking at 200 rpm till the cell density reached to OD600of 0.8-1.0.Cells were harvested by centrifugation at 5,000 g and washed once with 30 ml 2% ice-cold glucose solution. Cells were incubated in 15 ml solution containingglycine-NaOH(50 mM; pH10)andDTT(2 mM) at 30 ̊C for 10 min. After incubation, cells were normalized to adensity of1000OD600and resuspendedin 15 ml spheroplasting buffer containing 10-15mg of zymolyase20T.Cells were incubated at 30 ̊C for 45-60 minor till the spheroplasting was completed.Spheroplasts werecollected by centrifugation at 4,500 rpmfor 5 minat 4 ̊C, washed gently with15 ml 1.2 M sorbitol solutionandresuspendedin 3.5 ml 15%ficoll solution made in PS buffercontaining 1X protease inhibitor cocktail. This suspension was homogenized on ice with 20-25 strokes in a loose-fitting Dounce homogenizer. Homogenate was transferred to an ice-cold,ultra-clear Beckman ultracentrifuge tube, overlaid witha gradient of3 ml 8%ficoll solution, 2.5 ml 4%ficoll solutionand 2.5 ml PS buffer lacking ficoll and centrifuged at 1,10,000g(30,000 rpm)for 90 minat 4 ̊Cin a pre-cooled Beckman ultracentrifuge with SW41-Ti swinging bucket rotor.Centrifugation was carried out with slow acceleration and deceleration settings.White creamy vacuole membrane layer wascollected from the interfaceof 0and4% ficoll gradientwithout mixing the layers.Total protein concentration in thevacuole fraction was estimated using BCAprotein assay kit as described earlier
    14. Crude fractionation of total membraneswas carried outviadifferential centrifugation asdescribed previously (Moranoand Klionsky,1994)with slight modifications. Cells grown tolog-phase in YPDmedium werecollected, washed,normalizedto 10 OD600and resuspendedin 1 ml spheroplast buffer containing 1-2mg of zymolyase20T (MP Biomedicals).Following incubation at 30 ̊Cfor 30-45 min,spherolplastswerecollected by centrifugation at 800 g for 3 minat 4 ̊C and resuspendedin 1 mlice-cold Tris-EDTA (pH 7.5). Spheroplastswere lysed with 100 μl 0.5mm glass beads on a vortex mixer with 10 secpulsegiven thricewith intermittent ice-breaks.Cellsuspension was centrifuged at 800 g for 5 minat 4 ̊C to pellet unbrokenspheroplastsdown andthesupernatant was centrifuged at 15,000 g for 5 minat 4 ̊C to obtainthemembrane fraction pellet.Pellet was washed once with ice-cold Tris-EDTA (pH 7.5), resuspendedin 50 μl of the samebuffer and stored at -20 ̊Ctill further use. Protein concentration of pellet fraction was estimated using BCAprotein assay kit with BSA as thestandard
    15. A calibration curve of fluorescence intensity values versuspH was prepared for BCECF-AM-loaded wt cells by incubatingcellsin YPD medium containing 50 mM MES, 50 mM HEPES, 50 mM KCl, 50 mM NaCl, 0.2 M ammonium acetate, 10 mM NaN3, 10 mM 2-deoxyglucoseand5 μM carbonyl cyanide m-chlorophenylhydrazone, titrated to five different pH values in the range of 4.0-8.0. Fluorescence intensity values were measured by excitation at 440and 490 nm with emission at 535 nm and a graph was plotted between the ratio of intensity at 490 to 440 nm versuspH. Similar to pHi calibration curve, a polynomial distribution of fluorescent intensity signal and pH was observedfor BCECF-AMprobe
    16. fluorescence by excitation at 440 (pH-independent) and 490 nm (pH-dependent) with emission at 535 nm. Ratio offluorescence intensity at 490 to440 nm was used tocalculatethe vacuolar pH. Background fluorescence was removed by subtracting the fluorescence intensity values of cells without BCECF-AM from the fluorescence intensity values of the probe-loaded cells
    17. Vacuole pH inyeast cells was determined asdescribed previously (Padilla-López and Pearce, 2006). Briefly, log-phase,YPD medium-grown yeast cells were harvested and suspended in 200 μl YPD medium containing 50 μM 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein, acetoxymethyl ester (BCECF-AM; Invitrogen # B1150) to the final cell density of 4 x 107 cells. Cells were incubated at 30 ̊C for 30 min at room temperaturefollowed by three washeswith YPD medium. Washed cells were resuspended in 1 ml YPD medium and 200 μl cell suspension was used for recording
    18. Vacuolar morphology of C. glabratacells was examinedby staining vacuoleswith FM4-64 (Molecular Probes, Invitrogen). FM4-64 is a lipophilic dye that exhibits long wavelength red fluorescence when boundto lipids. FM4-64 binds to the plasma membrane and follows the endocytic pathway to reach the vacuole(Vida and Emr, 1995).Log-phase,YPDmedium-grown cells were harvested and washed with 1X PBS. 1 ODcells were resuspendedin 50 μl YPDmedium containing 30 μM FM4-64 andincubated at 30 ̊C for 30-45 min. After incubation, cells were washed thricewith YPD mediumand resuspendedin 100 μl of the samemedium. Cells were observed under confocal laser scanning microscope(Zeiss LSM 510 Meta)with 63X objective lens,2.5X final zoom, pinhole set at 108 μm and emission filterset to LP 565nmto capture fluorescence image.Along with the fluorescenceimage, aphase contrastimage was alsocaptured for each sample
    19. cellswere collected and washed with chilled sterile water.1 OD600cells were resuspendedin 20 μl chilled10%TCA solution containing 8 mM EDTA (pH 8.0) and incubated at room temperature for 15-20 min.Followingincubation, cellsuspension was centrifuged at 12,000 rpm for 5 minat 4 ̊Cand supernatant was transferred to a fresh 1.5 ml microcentrifuge tube. 10 μl of this supernatant fraction was diluted 75-foldwith ATPassay mix dilution buffer provided with the kit. 50 μl of diluted suspension was added to anequal volume of ATPassay mix (Sigma # FLAAM) which containedfirefly luciferase and luciferin with MgSO4, EDTA, DTT and BSA inTricine buffer.Luminescence was measured inluminometer (Varioskan flash-3001,Thermo Scientific). Total ATP was quantified usingpurified ATP as the standardand expressed in moles/OD cells
    20. ATPconcentrationin yeast cells was measuredby luminometricluciferase-luciferinbased assayusingATPbioluminescent kit(Sigma # FLAA).Briefly, log-phase yeast
    21. Estimation of total glycogen in cells was performed asdescribed previously (Parrou et al., 1997) with slightmodifications.Briefly, YPD medium-grown C. glabratacells were harvested, washed once with 1 ml ice-cold waterandresuspendedin 250 μl sodium carbonate(0.25 M)solution. After incubation at95 ̊C for 4 hin water bath with occasional stirring, cell suspension was cooled and pH of the suspension was adjusted to 5.2 by adding 150 μl 1 M acetic acid. Tothis suspension,600 μl 0.2M sodium acetatewas added and cell suspension was incubated with 1-2 U/ml of α-amyloglucosidase from A.niger(Sigma #A7420)at 57 ̊C for overnight with constant agitation.Resultant glucose liberated by α-amyloglucosidase digestion was collected in the supernatant fraction and quantifiedby phenol-sulphuric acid methodof carbohydratedetermination.For quantification, commercially available purified glucose was used as a standard and total glycogen incells was expressed as μg/2 x 107cells tonormalizeagainstcell density
    22. Trehalose from C. glabratacells was extracted by trichloro acetic acid (TCA)solutionas described previously (Lillie et al.,1980). Cells grown in YPDmediumwere collected at different time pointsof growth and washed thrice with ice-cold sterile water. Cells were immediatelystored at-20 ̊Ctill further use.For trehalose isolation, 10-20 OD600cells were thawed in 500 μl TCA (0.5 M) solutionon ice and incubated at room temperaturefor 1 h.Supernatant fraction was collected by sedimenting cells at 14,000 rpm for 5 minat 4 ̊C.TCA extractionwas repeated withcells once more and the resultingsupernatant was mixed with the earlier fraction.Extractedtrehalose was measuredby phenol-sulphuric acid methodof carbohydratedeterminationwithcommercially available purified trehalose(Becton, Dickinson and Co.) as a standard.Total trehalosecontent was normalized to the cell densityand expressed as μg/2 x 107cells
    23. Quantitative measurement of periplasmic acid phosphatase activity in phosphate-starved C. glabratacells was performedas mentioned previously (Orkwis et al., 2010). A total of 0.5 OD600YNB-grown and phosphate-starved cells were collected, washed thrice with cold water and oncewith cold 0.1 M sodium acetatebuffer (pH 4.2). Washed cells were resuspendedin 500 μl sodium acetate (0.1 M)and incubated at 30 ̊C with constant stirring. After 10 min incubation, 500 μl freshly-prepared solution of 20 mM p-nitrophenyl phosphate in 0.1 M sodium acetate(pH 4.2) was added to the cell suspension. Enzymatic activity was stopped after incubation at 25 ̊C for 20 min by addition of 250 μl sodium carbonate (1 M)tothe reaction mix. Resultant colour change was measured by monitoring absorbance at 400 nm. Acid phosphatase activity was expressed as a ratio of OD400to OD600 to normalize against cell density
    24. Determination of acid phosphatase activity
    25. Cells grown overnight in YNBmedium wereinoculated in fresh YNB mediumand incubated at 30 ̊C with shaking at 200 rpm. Cells were harvested when the cell density reached to an OD600of 0.6-0.8.Cells were consecutively washed with sterile MQ water and YNB without phosphate (YNB-Pi) medium. Washed cells were inoculated either in YNB orYNB-Pimediumto the initial OD600of 0.1. Cells were incubated at 30 ̊C for 3-4 h, harvested and resuspendedin 100 μlYNB-Pimedium. Radioactive P32-labelled o-phosphoric acid(Jonaki# LCP 32)was added to the cell suspension to a final concentration of 1 μCi/mlandcells were incubated for 30 min.For determining phosphate uptake, a10-12 μl cell suspensionaliquot,after every5 min,was removed and kept on ice.To this cell suspension, 500 μl ice-cold YNB-Pimediumwas addedand cells were harvested by centrifugation at 5,000 g for 5 minat 4 ̊C.These cells were washed with ice-cold YNB-Pimedium thrice and resuspendedin 100 μlPBS(1X). 10-20 μl of this cell suspension was added to5 ml scintillation fluid and β-decay counts were measured in ascintillation counter(Tri-Carb 2910 TR Liquid Scintillation Analyzer, PerkinElmer).Scintillation counts were normalized to total cell number and plotted with respect to time. Total phosphateuptake was expressed as P32c.p.m/OD600cellswhere c.p.m refers tocounts per min
    26. Total cellular polyphosphates were quantified viapolyacrylamide-Tris borate gel electrophoresis (PAGE-TBE).Briefly, PAGEwas performed with Tris-borate buffer (pH 8.3) todeterminethe quantityand the typeof polyphosphatesextracted fromyeaststrains. Equal amount of total RNA (20 to 100 μg) was loadedon 34%PAGE-TBE gel (22cm long, 16 cm wide and 0.8 mm thick) and electrophoresedat 500Voltsfor 20-24 hin cold-roomtill the marker dye bromophenol blue(BPB)had migrated 15-16 cm awayfrom the well.After electrophoresis, total polyphosphates werevisualizedby staining the gel with 0.05%toluidine blue staining solutionfollowed by destaining. Polyphosphates wereobserved both as asmearin the top most portion of the gel as well asdiscreet bands of long chain polyphosphatesand shortchain polyphosphatesin middle andbottom half of the gel,respectively.Polyphosphateband intensity in the gelwas quantified using ImageJ software (http://rsbweb.nih.gov/ij/)and relative amountsof long chain and short chain polyphosphatesin C. glabratacells werecalculated
    27. Polyphosphates from yeast cells were extracted with phenol-chloroform solutionas described previously(Neefand Kladde,2003). Cells grown eitherovernight or to logarithmic phase in YPDmediumwere harvested by centrifugation at 1,700 rpm for 5 min. Cells were washed with 10 ml sterile MQ water and resuspendedin ice-cold 500 μl20%trichloro acetic acid (TCA) solution to the final cell densityof 100 OD. Cell suspension was transferred toa1.5 ml microcentrifuge tube. After incubation at room temperature for 5 min, cells were harvested by centrifugation at 12,000 g for 10 minat 4 ̊C and resuspendedin 250-350 μlpolyphosphate extraction buffer.Equal volume of phenol-chloroform (25:24) was addedtothe microcentrifuge tube and aqueous phase was extracted by centrifugation at 12,000 g for 8 minat room temperature. Top aqueous layer was collected with a 200 μl tip. Aqueous layer extraction was repeated once more after removal of DNA with chloroform.After centrifugation,aqueous phasecontaining RNA and polyphosphates wascollected,RNA was quantified at A260nmandstored at -20 ̊C
    28. were maintained in log-phase by continuous passaging in fresh YNB medium every 4 h
    29. For phosphate starvation,yeastcells grown to log-phase in YNB medium were harvested,washed with water,transferred to either regular YNBor YNB medium lackingphosphate and were grown for 16 h at 30 ̊C. Cells cultured in YNB medium
    30. Plasma membrane H+-ATPase activitywas measured inthe total membrane fraction as described previously (Nakamura et al., 2001).5μg totalmembrane fraction was incubated at 30 ̊C in 120 μl reaction buffer containing 10 mM MgSO4and 50 mM KCl in 50 mM MES (pH 5.7) with 5mM adenosine tri-phosphate (ATP). To eliminate possible contribution of residual ATPases, viz.,vacuolar ATPases, mitochondrial ATPases or non-specific phosphatases, 50mM KNO3, 5mM NaN3and 0.2mM ammonium molybdate were used, respectively, in the assay mixture. Reaction was stoppedafter 30 minby adding 130μl stop-developing solution containing 1% (w/v) SDS, 0.6M H2SO4, 1.2%(w/v)ammonium molybdate and 1.6%(w/v) ascorbic acid. Amount of inorganic phosphate (Pi) liberated was measured at A750nmafter 10 minincubation at room temperature. A standard curve prepared with0-50 μmolesof KH2PO4 was used fordetermination of total Piamount.ATPase activity of the plasma membrane was expressed in micromoles of Pireleased per milligram protein per min. ATPase activity was also determined in the presence of plasma membrane H+-ATPase inhibitor diethylstilbestrol (DES,Sigma# D4628),wherein total membrane fraction was incubated with 0.2mM DES for 5 min, prior to the enzymatic measurement
    31. dithiothreitol and1X protease inhibitor cocktail. Cell suspension was rapidly frozen at -80 ̊C,thawed and lysed with 0.5mm acid-washed glass beadsin a homogenizer (FastPrep®-24,MP Biomedicals)at maximum speed of 60 secfive times. Homogenate wasdiluted with 5mlTris-HCl (0.1M; pH 8.0)solutioncontaining 0.33M sucrose, 5mM EDTAand 2mM dithiothreitoland centrifuged at 1,000g for 3 minat 4 ̊C. Supernatant was collected and centrifuged again at 3,000g for 5 minat 4 ̊C to remove unbrokencells. The resulting supernatant was centrifuged at 19,000g for 45 minat 4 ̊C to obtain total membrane fraction. Total membrane pellet was resuspendedin 100μl membrane suspension buffer and stored at -80 ̊Ctill further use. Total protein concentration in the membrane fraction was estimated using BCAprotein assay kit (Thermo Scientific, US) with bovine serum albumin (BSA) used as astandard
    32. Isolation of total membrane fractions from C. glabratastrains were carried out as described previously (Fernandes et al., 1998). Cells grown to log-phase under different environmental conditionswere harvested, washed and suspended to afinal density of 20 OD600cells in 1 ml solution containing100mM Tris (pH 10.7),5mM EDTA,2mM
    33. To assess the activity of plasma membrane proton pump, CgPma1, in cells grown in differentexternal pH environment,whole cell acidification assaywas carried out.This assay is a measurement of glucose-responsive proton pump activityin live cellsand is based on a decrease inthe pH of a weakly-buffered solutionupon extrusion of H+ions from thecell. The amount of change in the pH of the medium represents a crude measurement of the activity of functional plasma membrane proton pump in live cells. Whole cell acidification assay was conductedwithcellsgrown in YNB pH 5.5 and YNB pH 2.0medium as described previously (Martinez-Munoz and Kane, 2008) with slight modifications.After growth at30 ̊C for 2 h, cells were harvested, washed and resuspended(1.5-3.0 mg wet weight/ml) in 15ml MES/TEA (1mM; pH 5.0) buffer. Cell suspension was kept at 25 ̊C with continuousagitation. Extracellular pH of the buffer solution was recorded at 1 mininterval for 20 minwith the help of a pH meter(BT-600, BoecoGermany). To activate plasma membrane proton pumping, glucose and KCl were added to a final concentration of 40mM after 3 and 8 minincubation, respectively. Plasma membrane proton pump activitywas plotted as a change in the pH of the extracellular solutionversustime
    34. Log-phasecells grown in YPD medium containing or lacking CaCl2and FK506 were collected, PBS-washed and loaded with ratiometric, high affinity, membrane-permeable calcium indicator, Fura-2 AM (10 M; Sigma #47989). After 30 min incubation at 30◦C, labelled cells were washed thrice with cold PBS, suspended in PBS and fluorescence was recorded at 505 nm with dual excitation at 340 and 380 nm. The ratio of fluorescence intensities between 340 and 380 nm, representing Ca-bound and Ca-free Fura-2 molecules, respectively, reflected free intracellular calcium concentrations
    35. Intracellular reactive oxygen species (ROS)levels in yeast cells weredetermined usingfluorescent probe 2',7'-dichlorofluorescein diacetate (DCFH-DA; Sigma# D6883). Cellular esterasesremove the diacetate groups ofthe DCFH-DAand produceDCFHwhich getsreadily oxidized to highly fluorescent product 2′,7′-dichlorofluorescein (DCF) by intracellular ROS. The fluorescent intensity of DCF corresponds to the amount ofintracellular ROSpresent in the cell.Cells grown under different environmental conditions were harvested,washed once with tissue-culture grade phosphate-buffered saline (PBS) and resuspendedin PBS to the final cell density of 1 OD. Freshly-prepared DCFH-DA (0.01M stock in DMSO) was added to the cell suspension toafinal concentration of 100 μM. Cell suspension was mixed and incubated at 30 ̊C for 30 min. After incubation,cells were washed 2-3 times with 1 ml PBS and then resuspendedin 200 μlPBS. Fluorescence intensity values wererecorded usingspectrofluorophotometer (Varioskan flash-3001, Thermo Scientific) with excitation and emission at 488and 530 nm,respectively.Fluorescenceintensityvalues obtained from probe-loaded cells were subtracted from the fluorescence intensity values obtainedfrom cells-alone samplesto remove background fluorescence
    36. For determiningthe intracellular pH from fluorescence intensity values of CFDA-SE-loaded cells, anin vivocalibration curve was prepared between fluorescent intensity and pre-adjusted environmental pH values. Briefly,CFDA-SE-loaded wild-typeC. glabratacellswere incubatedwith 0.5 mM carbonyl cyanide m-chlorophenylhydrazone (CCCP; Sigma# C2759) at 30 ̊C for 10 min in 50 mM CP buffer adjusted to different pH values ranging from 4.0 to 7.5, with an interval of 0.5 unit.CCCP is an ionophore which dissipates the plasma membrane pH gradient, thus, rendering the intracellular pH similar to the extracellular pH. Fluorescent intensities were determinedand a calibration curvewas plotted between the ratio of intensity at 490 to430 nm versuspH.A polynomial distribution of fluorescent intensity signal and pH was observed for CFDA-SE probe(Figure2.1)and the graphequation was used todeterminethe intracellular pHof C. glabratacells
    37. OD600of 0.5and transferred to a 1.5 ml microcentrifuge tube. Probe loading was carried out by adding freshly-prepared CFDA-SE solution (0.01 M stock in DMSO) tocell suspension to a final concentration of 160 μM. Cell suspension was mixed on vortex mixerfor 10 secand incubated at 37 ̊C for 1 hwith shaking at 300 rpmon thermo mixer.Cells were harvested, washed twice with 1 ml 50 mM CP buffer to remove unloaded probe,resuspendedin 250 μl CP buffer andwereincubated at 30 ̊C for 30 minwith shaking to recover from the stress induced during probe loading. Afterincubation,fluorescent intensitywasdetermined with spectrofluorophotometer (Varioskan flash-3001, Thermo Scientific) by excitation at 430 nm (pH-independent) and 490 nm (pH-dependent) with emission at 525 nm. Background fluorescence of the probe was removed by subtracting the fluorescence intensity of the probe in CP buffer from the fluorescence intensity of the probe-loaded cells
    38. Intracellular pH(pHi)in yeast cells was determinedusing fluorescent 5,(6)-carboxyfluorescein diacetate succinimidyl ester (CFDA-SE; Molecular Probes) asdescribed previously (Bracey et al.1998). For pHiprobe estimation,YNB medium-grown log-phase cells were inoculatedin YNB, YNB-pH 2.0 or YNB medium supplemented with acetic acid and incubated at 30 ̊C for different time points.Log-phase C. glabratacells were harvested and washed twice with 50 mM citric-phosphate (CP) buffer (pH 4.0). Washed cells were resuspendedin 1ml 50 mM CP buffer to an
    39. Following transfer,membrane was either stained with Ponceau reagent for checking the efficiency of transfer or directly processed for proteindetectionusing protein-specificantibodies.For immunoblotting, membranes were blockedwith 5% (w/v)non-fat milk solutioneitherin PBS-T or TBS-T for 2 hat RTand probedwith primary antibodies against the target proteins.For detection of CgPma1, membranes were probed with1:1000 dilution of polyclonal anti-Pma1antibody raised against S. cerevisiaePma1 (Santa Cruz #sc-33735)in PBS-T with 5% (w/v)fat-free milk for overnight at 4°C.For detection of phosphorylated form of CgSlt2,immunoblotting analysis was done withan anti-phospho-p44/42 MAPK (Thr202/Tyr204) primary antibody raised against human p44 MAPK(Cell signalingtechnology# 4370S) at a dilution of 1:6000 in TBS-T with 5% (w/v)fat-free milk for overnight at 4°C.For detection of CgCPY, membrane was incubated with polyclonal anti-CPY antibody raised against S. cerevisiaeCPY(Thermo Scientific # PA 1-27244) at a dilution of 1:10,000 in TBS-T with 5% (w/v)fat-free milk for overnight at 4°C.For CgGapdhdetection,anti-Gapdh primary antibody raised againsthuman Gapdh(Abcam # ab22555) at a dilution of 1:7000was usedin TBS-T with 5% (w/v)fat-free milk.Secondary antibodies conjugated with horseradish peroxidase(HRP)enzymewereusedin 1:10,000 dilutionto detect the immune-reactivity of primary antibodieswith the help of ECL plus Western blotting system (GE Healthcare)as per manufacturer’sinstructions
    40. Total proteins resolved bySDS-PAGE were transferred to PVDFnylon membrane by Western blotting using a Bio-Rad Mini Trans-Blot electrophoretic transfer unit in Tris-glycinetransfer bufferat 4 ̊C either at 100 Voltsfor 3 hr or 30 Voltsfor overnight
    41. SDS-PAGEwas performed as described previously (Laemilli, 1970).10-40 μg protein samples were mixed with 4X SDS loading buffer and either incubated at 50 ̊C or 90 ̊C for 10 min. Denatured samples were loaded either on8%or 10%SDS-PAGEgel and run in Tris-Glycine-SDSgel running buffer at 70-100 Volts for 2-3 hin a Mini-PROTEAN®3electrophoresis unit(Bio-Rad).After electrophoresis,gels were either visualized by coomassie brilliant blue (CBB) stainingor processedfor western blotting as described below
    42. Log-phase yeast cell cultures were harvested and total protein was extracted by lysingyeast cells using glass beads. Briefly,10 mllog-phase yeast culturesgrownin appropriate medium were harvested,washed once with ice-cold water and suspended in 250 μl homogenizing buffer containing 1 mM phenylmethylsulfonylfluoride(inhibitsserine proteases), 10 mM sodium fluoride(inhibit Ser/Thr and acid phosphatases), 1 mM sodium orthovanadate (inhibits Tyr and alkaline phosphatases) and 1X concentration of protease inhibitor cocktail(RocheCat # 04693159001). Cells were lysedwith glass beads by vortexing five times at high speed for 1 min with intermittent 1 min ice breaks. Unbroken cells and cell debris were removed by centrifugation at 1,000 g for 5 min at 4 ̊C. Cell lysate was collected and protein was quantified using bicinchoninic acid (BCA)protein assay kit (Thermo Scientific # 23227) as per supplier’s instructions
    43. hybridizations from biological replicates for each sample. Data was extracted with Feature Extraction software v 10.5 (Agilent) and normalizedwith GeneSpring GX v 11.0.1 (Agilent) software using the recommended Percentile shift Normalization to 75th percentile. Raw Data sets for this study are available at http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=


    44. Log-phase wild-type and Cgyps1∆cells were grown in YNB and YNB-pH 2.0 medium. After 1 h incubation, yeast cells were collected, washed and were stored in RNAlater at -80°C. These frozen samples were sent to Genotypic Technology Ltd., Bangalore(http://www.genotypic.co.in) whichprovides services of global gene analysis on Agilent platform. A 8x15k GE array comprised of 60mer oligonucleotidesfor a total of C. glabrata5503 genes was used wherein average number of replicates for each probe was three. Labeling was done in single color and data is the average of two
    45. .coliBW23473 electro-competent cell aliquots werethawed on ice and mixed with 1-2 lof plasmid DNA. Mixture was pulsed with the Gene Pulser®electroporation apparatus(Bio-Rad) at 1800 Volts with 25 μF and 200 Ωcurrentin a chilled0.1 cm electroporation cuvette(Bio-Rad). Immediately after successful pulsing, 1 ml LB medium was added to the cuvetteand suspension was transferred toa 1.5 ml sterile centrifuge tube. Cells wereincubated at 37°C for 1 hwith shaking and further plated onLB plates containing kanamycin(30μg/ml). Positive colonies were inoculated in LBliquid medium containing kanamycin(30μg/ml)for plasmid isolation


    46. A single colony of E.coliBW23473strainfrom a freshly-streaked LBplate was inoculated in50ml LB medium. Culture was incubated overnight at 37°C with shaking at 200rpm. 25ml of the overnight-grown BW23473 culturewas transferred to500ml pre-warmed LB medium andincubated at 37°C till the OD600reached to 0.4. After incubation, cultureswere transferred to an ice-water bathandcentrifugeat 1,000g for 15 minat 4°C. Cells were washed twice with 500ml ice-coldwater, thrice with250ml ice-cold 10% glycerol solution and resuspendedin 1ml 10% glycerol solution. Cell suspension wasnormalized to final cell densityof 3x 1010cells/ml and dispensed in 50μl volume into sterile ice-cold microcentrifuge tubes. Aliquots weresnap frozen inliquid nitrogen and stored at -70 ̊C for further use
    47. the disrupted gene, BLAST N of the sequences from rescued plasmids was performedagainstC. glabrataGenolevures database (http://www.genolevures.org/blast.html
    48. Identification of disrupted locus in Tn7insertion mutants was carried out as described previously(Kaur et al.,2004). Disrupted locus in each mutant is physically marked with a mini Tn7 transposon derivative containing conditional origin of replication R6K(facilitates Tn7recovery), S. cerevisiae URA3and Klebsiella pneumoniae hphgene (confers resistance to hygromycin B)(Castaño et al.,2003). Briefly,genomic DNA was isolated fromovernight grown Tn7insertion mutants using spheroplast lysis method. After RNAse treatment, 10μgDNA was either digested withMfe1or SpeIrestriction enzymeas the Tn7 cassette lacks these enzyme sites. Followingovernight digestion, DNA wasprecipitated with 1ml ethanol and 1/10thvolume of 3 M sodium acetate (pH 5.2).DNApellet was washed twicewith ice-cold 70% ethanol, air driedand resuspendedin sterile MQ water. DNA was recircularized withT4 DNA ligase. Resultant circular plasmid contains the Tn7cassette flanked on either side by the gene,it has disruptedin the genome of C. glabrata.This circular plasmid DNA was transformedin E.coliBW23473 strain,which contains protein Π (the product of the pir gene)required by R6Korifor replication.Transformation of circularized DNA in E.coliBW23473 electrocompetent cells was performedas described below.Plasmids fromselected transformants were isolated and sequenced with outward primers from Tn7right and left ends to sequencethe disrupted gene fragment.For identification of
    49. C. glabrataTn7insertion mutantlibrary was screened for reduced growth in YNB-pH 2.0 medium. Thismutant library,composed of 9,134 Tn7insertion mutants, isarrayed in 96-well microtitre plates(Castaño et al.,2003). 2 μlof each mutant strain was inoculated in 120μl YNB medium and grown overnight at 30 ̊C in an incubator with constant shakingat 120 rpm. Overnight grown cultures were 120-folddiluted with 1X PBS in a 96 well block and transferred, using a 96-well pin replicator, to YNB and YNB-pH 2.0 medium. Plates were incubated at 30°C and mutant phenotypes were recorded after 3-4days.
    50. and colony purified on CAA plate. 15% glycerol stocks were made for two independent transformants and stored at -80 ̊C
    51. C. glabrataCgYPS7ORFwas cloned in a self-replicating pGRB2.2plasmidwhich contains C. glabrata CEN-ARS, S. cerevisiaeURA3gene, S. cerevisiaePGK1promoter and C. glabrataHIS3-3′ untranslated region. For cloning CgYPS7in pGRB2.2,CgYPS7ORF (1.764 kb) was PCR-amplified from the wild-type genomic DNA with high fidelity Platinum PfxDNA polymeraseusing primers carrying restriction sites for XbaIand XhoI. The1.764 kb amplifiedPCR product waspurified with QIAquick PCR purification kit (Qiagen # 28104),digested with XbaI and XhoI and cloned in the pGRB2.2plasmid at XbaI–XhoI sites in the multiple cloning site (MCS)region downstream of the PGK1promoter.Positiveclones were verified by PCR, sequencing and complementation analysesofCgyps7∆mutant. Yeast transformantsobtained by lithiumacetate methodwere selected on plates lacking uracil
    52. stranded DNA. Final reaction volume was adjusted to 20 μl with DEPC-treated waterandamplificationreaction was carried out usingthese parameters: initial denaturation at 95 ̊C for 5 min followed by 40 cycles of denaturationat 95 ̊C for 30 sec, annealing at 55 ̊C-57 ̊C for 30 sec, elongation at 72 ̊C for 40 sec and final extension at 72 ̊C for 10 min. Transcript levelswerequantified with an end-point value known as Ct (cycle threshold). The Ctdefines the number of PCR cycles required forthe fluorescent signal of SYBR green dye to cross more than the background level. The Ctvalue isinversely proportional to the amount of nucleic acid product. Ctvalues were obtained during exponential phase of amplification and used forcalculation of relative-fold change in gene expression after normalization to Ctvalues ofeither housekeeping gene ACT1 (gene encoding actin)orTDH3 (gene encoding Gapdh)with the help of the following formula. Fold change in expression = 2-∆∆Ct∆∆Ct= ∆Cttreated -∆Ctuntreated∆Cttreated = Ctvalue forgene of interest under test/treatedcondition -Ctvalue forinternal controlgene(ACT1/TDH3) under test/treatedcondition∆Ctuntreated = Ctvalue forgene of interest under untreatedcondition -Ctvalue forinternal control (ACT1/TDH3)gene under untreatedcondition
    53. Todeterminethe expression level of a specific gene, quantitative real-time polymerase chain reaction (qRT-PCR/qPCR)was performed oncDNA usinggene specific primers. Primers for qPCR weredesigned in such a way so as to get amplification products in a size range of 150 to 300 bp. Optimalprimer and cDNA concentrationswere standardized and qPCR was performed in ABI Prism 7000/7500 Real time PCR Machine (Applied Biosystems). Briefly, 0.4 μl cDNA was mixed with 0.1 to 0.2 picomolesof gene specific forward and reverse primers and 10 μl 2X MESA GREEN qPCR™Mastermix Plus containing SYBR green dye (Eurogentec) in awell of a96-well PCR plate (Axygen). SYBR green is a dye that specifically binds to double
    54. 1 μg good quality RNA was treated with DNase I (amplification grade, Invitrogen) to remove DNA contamination and used for complementary DNA (cDNA) synthesis using reverse transcriptase enzyme and oligo-dT primers.SuperScript®III First-Strand Synthesis System (Invitrogen) was used to carry out cDNA synthesis reaction according to the manufacturer’s instructions. cDNA was stored at -20 ̊C
    55. autoclavable plastic items to removeRNase contamination. RNA was isolated from C. glabratacells using hot phenol extraction strategy.Log-phase cells well harvested at 5,000 g for 5 min at 4 ̊C, resuspended in 1 ml ice-cold DEPCwater and transferred to a 2 ml microcentrifuge tube. Cells were spun down at 6,000 g for 3 min at 4 ̊C and resuspended in 350μl AEsolution. 50 μlSDS and 400 μl acid phenol wereadded tothe above tubeand mixed well by vortexing. Tubes were incubated at 65 ̊C for 15minwith continuousmixing. After incubation, tubes were kept on ice for 5 min and centrifuged at 12,000 rpm for 5 min at 4 ̊C. Aqueous phase was collected and re-extracted with an equal volume of cholroform. Total RNA was precipitated at -20 ̊C with1/10thvolume of 3 M sodium acetate (pH 5.2) and 2.5 volume of ice-cold 100% ethanol and collected by centrifugation at 12,000 rpm for 5 min at 4 ̊C. RNA pellet was washed with ice-cold 70% ethanol and resuspendedin 100 μl commercially available DEPC-treated water (Sigma # 95284). RNA concentration was measured byrecordingabsorbance at 260 nm. Purity of RNA sample was checked by A260nm/A280nmratio where ratio of >1.8 was considered as good quality RNA. RNA integrity was checked by gel electrophoresis on 8% agarose gel made in DEPC-treated TAE buffer
    56. All solutions were made in RNase free diethylpyrocarbonate(DEPC)water. Microcentrifuge tubes and tips employed for RNA workwere autoclaved twice and kept at 70 ̊C for overnight before use. RNaseZap®(Ambion) was sprayed on non-
    57. Themethod was used for isolation of good quality genomic DNA that wasused to map Tn7insertionin C. glabratamutants.Briefly,10 mlsaturated yeast culturewasharvested, resuspendedin 1 ml sterile water and transferred toa2 ml microcentrifuge tube. Cells were pelleteddown by centrifugation at 4,000 rpm for 5 min. Supernatant was discarded and the pellet was resuspendedin 500 μl freshly prepared solutioncontaining100mM EDTAand 5% β-mercaptoethanol andincubated at 42 ̊C for 10 min. After incubation,cells were spun down at 5,000 rpm for 1 minand resuspendedin 500μl freshly-prepared BufferB. One tip full of lyticase(Sigma # L4025) was added and cellsuspension was incubated at 37 ̊C for 1 h. Following incubation,cell suspension was spun down at 6,000 rpm to recover spheroplasts.Spheroplasts weregently resuspendedin 500μl BufferCand DNA was twice extracted with 500μl phenol:chloroform:isoamyl alcohol (25:24:1)solution.Aqueous layer was collected in a new 2ml microcentrifuge tube and DNA was precipitated with 1ml ethanol and 1/10thvolume of 3M sodium acetate (pH 5.2)by centrifugation at 13,000 rpm for 5 min. Pellet was resuspendedin 200 μl TE containing 0.3 μl of RNase Cocktail™and incubated at 37 ̊C for 30 min.After incubation, 300 μl additional TE was added and DNAwas re-precipitated withethanol and 3 M sodium acetateas described above. Pellet was washed with 70% ethanol anddried under air. DNA pellet was finally suspended in 100 μl TE and stored at -20 ̊C
    58. phenol:chloroform:isoamyl alcohol (25:24:1)was added to the tube and mixed thoroughly.Aqueous phase was collected after centrifugationat 12,000 rpm for 3 minand was transferred toanew 2 ml microcentrifuge tube.1 ml absoluteethanol was added to the aqueous phase and DNA was precipitated by centrifugation at 12,000 rpm for 8 minat 4 ̊C.DNA pellet was washed with chilled 70%ethanol and dried under air. DNA pellet was resuspendedin 50 μl TE containing 0.3 μl of RNase Cocktail™(Ambion®# AM2286)and incubated at 50 ̊C for 20 min. 200 μl additional TE was added to the above suspension and DNA was stored at -20 ̊C
    59. In this method of genomic DNA extraction,yeast cells werelysed by mechanical disruption with glass beads. Briefly, yeast cells were harvested after overnight growth in YPD medium, resuspendedin 500 μl waterand transferred toa2 ml microcentrifuge tube.Cells were pelleteddown at 10,000rpm for 1 min. Resulting supernatant was discarded and the pellet was resuspendedin 500 μl Buffer A. The tube was incubated at 65 ̊C for 15 min. After incubation, 500 μl ofphenol:chloroform:isoamyl alcohol (25:24:1) and 0.5 gm of acid-washed glass beads (Sigma # G8772) were addedto the tube. Cells were lysed by three cycles of high speed vortexing withintermittent ice breaksfor 45 secand pelleteddown at 12,000 rpm for 3 minat 4 ̊C.Uppermost aqueous phase was transferred to a 2 ml microcentrifuge tube,500 μl of
    60. This quick extraction method was used to isolate genomic DNA which was used as templateto amplify gene of interestor toverify the knock-out. C. glabratacells were grownovernight to saturation in 10 mlYPD medium at 30 ̊C.Cells were harvested at 4,000 rpm for 5 min, resuspendedin 400 μl Buffer Acontaining 50 mM Tris-HCl, 10 mM EDTA, 150 mM NaCl, 1%Triton X-100 and 1%SDSand weretransferred to a2 ml microcentrifuge tube. Equal volume ofphenol-chloroform solution was added to the abovesuspensionfollowed byvortexingfor 2-3 minand incubationat 42 ̊C for 30 minwithcontinuous agitation at 800 rpm on thermomixer (Eppendorf). Cell debris was removed bycentrifugation at 12,000 rpm for 5 minand aqueous fraction(~ 350 μl)was transferred to a new 2 ml microcentrifuge tube.0.3 μl RNaseCocktail™(Ambion® # AM2286) containing RNase A (500 U⁄ml) and RNase T1 (20,000 U⁄ml) was added and tubes were incubated at 37 ̊C for 30 min. DNA was precipitated with 2.5 volumesof chilled ethanol and 1/10thvolume of 3 M sodium acetate (pH 5.2).DNA pellet was washed with chilled 70%ethanol and semi-dried under air.Pellet was suspendedin 100μlTE (10 mM Tris-HCland 1 mM EDTA; pH 8.0)and stored at -20 ̊C.DNA concentration was determined by recordingabsorbance at 280 nmin Nanodrop (Nanodrop ND-1000, Thermo Scientific).
    61. Based on the subsequent use, DNA from C. glabratacells was extracted using three different methodologie


    62. C. glabratayeast cells were grown overnight in 5 ml YPD medium at 30 ̊C. An aliquot from the overnight culture was inoculated in 10 ml fresh YPD medium to an initial OD of 0.1. Cells were incubated at 30 ̊C till the cultureOD600was between 0.4 and 0.6. Cells were harvested in a sterile 50 ml centrifuge tube and washed twice with sterile Milli-Q(MQ)water. Washed cells were suspended in 100 μl of 100 mM LiOAc, mixed thoroughly and transferred to a sterile 1.5 ml microcentrifuge tube. A transformation mix containing 240 μlpolyethylene glycol(PEG) (50% (w/v)), 36 μl LiOAc(1 M), 25μl ultrapure single-stranded salmon sperm DNA (2 mg/ml) (Clonetech) was added to 50 μl cell suspension. 50 μltransforming DNA (1μg circular plasmid DNA) was added to the above suspension. Whole mixture was vortexed gently and incubated at 30 ̊C for 45 min. 43 μl DMSO was added to the tubeand incubated at 42 ̊C for 15 min. Cells were collected after centrifugation at 5,000 rpm for 1 min and suspended in minimal medium containing 0.6% Bacto-Casamino acid. Transformation mixture was plated on CAA plates and transformants were selected for uracil prototrophy
    63. 5-10 ml saturated bacterial culture harboring the desired plasmid was harvested at 5,000 g for 3 min. Plasmid DNAwas isolated using QIAprep Spin Miniprep Kit (Qiagen, USA) or GenElute™ HP Plasmid Miniprep kit (Sigma-Aldrich, USA) as per manufacturer’s instructions
    64. E. coli DH5α ultra-competent cells were transformed with plasmid DNA by heat shock at 42 ̊C for 90 sec as described previously in Molecular Cloning-A Laboratory Manual (Sambrook and Russell,2001). Bacterial transformants were selected on LB agarmediumcontaining appropriate antibiotics. Transformants obtainedwere colony purified on LB plates containing antibiotics.Presence of the desired insertwas first verified by colony PCR followed by PCRusing extracted plasmid DNA as template
    65. suspension was kept on ice for 10 min and 50 μl volume was aliquoted to chilled sterile microcentrifuge tubes. Cellswere immediately snap-frozen in liquid nitrogen and stored at -80 ̊C
    66. A single colony of E.coli DH5-α strain was inoculated in 10ml LB medium and incubated at37 ̊C for overnight. 4 ml of thisovernight culture was inoculated in 2 lt SOB medium and incubated at 18 ̊C till theOD600reaches to 0.5. Cells were harvested by centrifugation at 2,500 g for 10 min at 4 ̊C and washed gently in 80 ml ice-cold Inoue transformation buffer. Cells were collectedby centrifugation at 2,500 g for 10 min at 4 ̊C and gently resuspended in 20 mlice-cold Inoue transformation buffer. To this cell suspension, 1.5 ml sterile DMSO was added and swirled gently. Cell
    67. All experiments in this studywere performed with log-phase cellsunless otherwise mentioned. For obtaining log-phase cells, overnight YNB-or YPD medium-grown yeast cellswerere-inoculated in fresh YNB or YPD medium to an initial OD600of 0.1-0.2.Cells were incubated at 30 ̊C with shaking at 200 rpmtill the OD600reached to 0.4-0.6 OD. After incubation, log-phase cellswere collected bycentrifugation at 4,000 rpm for 3 min,washed once with the same medium and usedforfurtheranalysis
    68. C. glabratastrains were grown overnighteither in YPDor YNBliquid mediumat 30 ̊C with shaking at 200 rpm. Cells were harvested and suspended in 1X PBS to a final OD600of 1.0.Five 10-fold serial dilutions of cell suspension wereprepared in PBS and3-4μlwasspotted on YPD/YNBplates containing various test compoundsusing a multi-channel pipette.Plates were incubated at 30 ̊C and growth profileswererecorded after2-4days
    69. Yeast cell viability was measured by plating appropriate dilutions of cell cultureonYPD plates at various time intervalsduringgrowth.Cell suspension was diluted in1X PBS. YPD plates were incubated at 30 ̊C for 2-3 daysand total colony forming units(CFUs)were calculated by counting the number of coloniesthat appeared onYPDplatesand dividing that number by anappropriate dilution factor
    70. preparedin appropriate solvents, sterilizedby autoclaving or filtrationand stored at appropriate temperature
    71. For growth analysisof C. glabratastrains, a single colony from YPD or YNBagar mediumwas inoculated in appropriate liquid medium and incubated at 30 ̊C with shaking at 200 rpmfor 14-16 h. This overnight grown culture was used toinoculatetest medium to an initial OD600of 0.1to 0.3.Optical density/Absorbance of the cell suspensionwas measured using Ultraspec 2100 pro UV/visible spectrophotometer (Amersham Biosciences) at600nmat regular time-intervals up to a period of 96 h.Absorbance values were plotted with respect to time. Generation time of yeast strains wascalculated fromthe logarithmic (log) phase of cellgrowth. Growth profilesbetween 4 (t1)and 8 h(t2)time interval wereconsideredfor calculationof generation time usingfollowing formula. Generationtime(G)= (t2-t1) x {log (2)/ [log (Bf/Bi)]}G= Generation time in ht1=Initial timepoint taken for analysist2 = Final timepoint taken for analysisBf= Number of cells at time t2(calculated on the basis of OD600values, wherein1 OD600of C. glabratacorresponds to 2 X 107cells.)Bi= Number of cells at time t1(calculatedas mentioned above)Severalyeast strains used in this study were analysed for their susceptibility to variouschemical compounds,drugsand metal ions. For this purpose, stock solutions were
    72. mM final concentration) and pH was adjustedto the desired valueby addition of HCl or NaOH. Medium was sterilized by autoclaving.YNBagar plates ofdifferent pHwereprepared by mixing equal volume of separately autoclaved 4% bacto-agar solution and2X varied pH-adjusted-YNB liquidmedium.All routine sterilization of mediumand solutionswas either carried outby autoclaving at 121 ̊C for 15-20 minat highpressure condition(15 psi)or filtration with 0.2 μmpolyvinylidene fluoride(PVDF) membranefilter unit (Millex®-GV, Millipore).Both yeast and bacterial strains were stored as frozen 15% glycerol stock at -80 ̊Cfor extendedlifetime
    73. C.glabratastrains were maintainedeither on rich YPDor synthetically-defined YNB medium. C.glabratacells were routinely culturedat 30 ̊Cwith shaking at 200 revolutions per min(rpm)unless otherwise mentioned. Forgrowthexperiments, C. glabratastrains were freshly revived on YPDmediumfrom glycerol stocks.Escherichia coliDH5α bacterial strainwasused for plasmid transformation and propagationpurposes and maintained on LB medium.E.coliBW23473 bacterialstrainwas used to rescue Tn7transposon cassette from C. glabrataTn7insertion mutantsand maintained on LB medium. Bacterial strainsharboring plasmids were maintained on LBagar plates supplemented withappropriate antibiotics.For plasmid isolationpurpose,bacterial strains were grown overnight in liquid LB brothcontainingappropriate antibiotics at 37 ̊C with shaking at 200 rpm. Forpreparation of the solid medium, 2%bacto-agar was added to the mediumand autoclaved. To prepare medium of different pH, YNB mediumwas either buffered with citrateor HEPESbuffer (100
    74. Oligonucleotides/primers used in this study were designed using either free online-tool Primer3 (http://frodo.wi.mit.edu/) or Gene Runner software (http://www.generunner.net/). Oligonucleotides used in this study were commercially
    75. synthesized from MWG Biotech Pvt. Ltd., Bangalore. All primers used in this study are listed in Table 2.3.Table 2.3: List of primers used in this study
    76. 10mM EDTA0.1% SDS 1 M ureaToluidine blue staining solution:0.05% Toluidine blue20% Methanol2% GlycerolSolution was prepared in H2O.Destaining solution for polyphosphate gels:20% Methanol2% GlycerolSolution was prepared in H2O.Spheroplast buffer:50 mM Potassium phosphate (pH 7.5)0.6M Sorbitol0.2 X YPD mediumPS(PIPES-Sorbitol)buffer:10 mM PIPES-KOH (pH 6.8)200mM Sorbitol1 X protease inhibitor cocktail (Roche Cat # 04693159001)**To be added fresh before use
    77. Citric-Phosphate buffer:0.5 M citric acid0.5 M dibasic sodium phosphatepH was adjusted to 5.0 with phosphoric acid and filter-sterilized.MES/TEA buffer:1 mM MES(2-(N-morpholino)ethanesulfonic acid)pH was adjusted to pH 5.0 with TEA(triethanolamine).Plasma membrane suspension buffer:50 mM Tris-HCl(pH 7.5)0.1mM EDTA0.1 mM Dithiothreitol 20% GlycerolPolyphosphate extraction buffer:50 mM HEPES (pH 7.2)
    78. Genomic DNAisolation buffersBuffer A:50 mM Tris-HCl10mM EDTA150 mM NaCl 1% Triton-X 1% SDSBuffer B:50 mM Tris-HCl (pH 7.5)10 mM EDTA1.1 M Sorbitol50 mM β-mercaptoethanol(To be added just before use
    79. 15% Acetic acidTris-Borate Saline(TBS):25 mM Tris150 mM NaClpH was adjusted to 7.4withHCl.This was prepared as 10 X stock solution and used at 1 X concentration.Blocking and wash buffers(PBS-T and TBS-T):5% Fat-free milk 0.1% Tween-20 Volume was made to 100 ml either with 1 X PBS(PBS-T)or 1 X TBS(TBS-T)
    80. 0.02% Bromophenol blue 2% DTT This was prepared as a 4 X stock solution and used at a 1 X concentration.SDS-PAGE running buffer:0.25 M Tris-HCl (pH 8.0) 1.92 M Glycine 1% SDS This was preparedas a 10 X stock solution and used at a 1 X concentration.Coomassie brilliant blue (CBB) staining solution:50% Methanol10% Acetic acid0.1% Coomassie brilliant blue-R250Western blotTransfer buffer:0.25 M Tris-HCl (pH 8.0) 1.92 M Glycine 1% SDS Thiswas preparedas a 10 X stock solution and used ata 1 X concentration.1X Transfer buffer (1litre):200 ml of methanol 100 ml of 10 X transfer buffer 700ml of waterPonceau 3S staining solution:0.25% Ponceau 3S40% Methanol
    81. SDS-PAGE30% Acrylamidesolution29 g Acrylamide1 g Bis-acrylamideDissolved in 100 ml H2O.10% Sodium Dodecyl Sulfate (SDS):10 g SDS in 100 mlH2OResolving gel mix (12%) (15 ml): 4.89 ml H2O6 ml 30% acrylamide:bisacrylamide (29:1) mix3.8 ml 1.5 M Tris-HCl (pH 8.8) 150 μl 10% SDS 150 μl 10% APS 10 μl TEMEDStacking gel mix (3 ml):1.689 ml H2O500 μl 30% acrylamide:bisacrylamide (29:1) mix380 μl 1 M Tris-HCl (pH 6.8) 30 μl 10% SDS 30 μl 10% APS 10 μl TEMEDSDS loading buffer:130 mM Tris-HCl (pH 8.0) 20% (v/v)Glycerol 4.6% (w/v) SDS
    82. Whole cell lysis buffer(Homogenizing buffer):50 mM Tris-HCl(pH 7.5)2 mM EDTA10 mM sodium fluoride*1 mM sodium orthovanadate*1 X protease inhibitor cocktail (Roche Cat # 04693159001)**To be added fresh before use
    83. Buffer C:100 mM Tris-HCl (pH 7.5)10 mM EDTA10% SDSRNA isolation bufferAE buffer: 3 M Sodium acetate0.5 M EDTA(pH 8.0)Phenol:Chloroform:Isoamyl Alcohol (25:24:1)solution:25 volume of Phenol24 volume of Chloroform1 volume of Isoamyl alcholDNA sampleloading buffer:0.25% Bromophenol blue0.25% Xylene cyanol15% Ficoll
    84. 15 mM CaCl2.2H2O 250 mM KCl 55 mM MnCl2.4H2O pH was adjusted to 6.7 with 1 N KOH. MnCl2needsto beaddedseparately,drop by drop with stirring, tothe buffer. PIPES goes into solutionwhenpH is greater than 6.7. The solution, after pH adjustment to 6.7 was filter-sterilized and stored at -20ºC.Reagents for yeast transformation:1 M Lithium acetate (LiOAc)50% Polyethylene glycol10 mg/ml Carrier DNADimethylsulfoxide (DMSO)
    85. INOUE transformation buffer:For bacterial DH5α ultra-competent cells preparation10 mM PIPES (free acid)
    86. 10 mM Tris-HCl (pH 8.0)1 mM EDTA Tris-Acetic acid EDTA (TAE) buffer:40 mM Tris base 0.5 M EDTApH was adjusted to 8.5 with glacial acetic acid.This was prepared as a 50 X stock solution and used at a 1 X concentration. Tris-Borate EDTA (TBE) buffer:90 mM Tris-borate 2 mM EDTA (pH 8.0) pH was adjusted to 8.3withHCl.This was prepared as a 10 X stock solution and used at a 1 X concentration.Both TAE and TBE were used asstandard gel electrophoresis buffers.HEPES buffer:This was used to prepare YNB medium of different pH.1M HEPESpH was adjusted to 7.5withNaOH.Bufferwas filter-sterilized and stored in an amber-coloured bottle. Citrate buffer(0.1M, pH 5.5):4.7 volume of 0.1 M Citric acid 15.4 volume of 0.1 M Sodium citrate
    87. Phosphate-Buffered Saline (PBS):137 mM NaCl 2.7 mM KCl10 mM Na2HPO42 mM KH2PO4pH was adjusted to 7.3.This was prepared as a 10 X stock solution andused at a 1 X concentration.Tris-HCl buffer:0.5 M TrizmaBase pH was adjusted to7.6 using concentrated HCl.This was prepared as a 10 X stock solution andused at a 1 X concentration.Tris-EDTA (TE)buffer:
    88. 0.67% Yeast Nitrogen Base2% DextroseYeast Carbon Base (YCB):1.17% Yeast CarbonBase1% DextroseCAA:0.67% Yeast Nitrogen Base 2% Dextrose0.6% Casamino acids Plates weremade by adding 2% agar
    89. Yeast Extract-Peptone-Dextrose (YPD):1% Yeast extract2% Peptone 2% DextroseYeast Nitrogen Base (YNB)
    90. Luria Bertani (LB):0.5% Yeast Extract1% Tryptone 1% NaCl LB-ampicillinand LB-kanamycin plates:LB medium50 μg/ml ampicillin30 μg/ml kanamycinSuper Optimal Broth (SOB): 0.5% Yeast extract2% Peptone 10 mM NaCl2.5 mM KCl10 mM MgCl210 mM MgSO4
    91. Bacterial medium
    92. antibodies,anti-mouse IgG andanti-rabbit IgG conjugated with horseradish peroxidase (HRP) were obtained from Cell Signaling Technology, USA
    93. All chemicals were purchasedfrom commercial sources. Mediacomponents for bacterial and yeast growthwere obtained from BD (Becton, Dickinson and Company, USA). Other chemicals were purchased from Sigma-Aldrich Co., USA. Materials used in recombinant DNA experiments were primarily obtained from New England Biolabs, Invitrogen, Bangalore Genei and MBI Fermentas. SuperScript™ III first-strand synthesis system was purchased from Invitrogen.MESA GREEN qPCR MasterMix Plus for SYBR®Assay was purchased from Eurogenetec. Kits used for plasmid isolation, PCR product purificationand DNAgelextractionwerefrom Qiagen.Radioactive chemical, ortho-P32-phosphoric acid,wasprocured from BRIT-Jonaki, CCMB, Hyderabad.Anti-Pma1 polyclonal antibody raised against S. cerevisiaePma1 was purchased from Santa CruzInc.,USA. Anti-phospho-p44/42 MAPK (Thr202/Tyr204) was purchased from Cell Signaling Technology, USA. Anti-CPY polyclonal antibody raised against S. cerevisiaeCPY was procuredfrom Thermo Scientific. Anti-Gapdh antibody raised against human Gapdh was purchased from Abcam. Secondary
    94. All C. glabratastrains and plasmids used in this study are listed in Tables 2.1 and 2.2, respectively.Table 2.1: List of yeast and bacterial strains used in this study
  2. sg.inflibnet.ac.in sg.inflibnet.ac.in
    1. activated TLC silicagel-60plate and transferred to theTLC chamber. After the solvent had migratedupwards (1.5 cm fromthetop), TLC plate was removed, air dried behind perspex shield, wrapped with cling plastic wrap and was exposed to phophorimager screenfor 2 h. Phosphorimager screen was scanned usingaFugi-FLA 9000 scanner
    2. To resolvephospholipids,a TLC chamber was prepared by pouring50 ml developing solution and sealing the chamber with aluminium foil so that developing solution can generate vapor. TLC silicagel-60plate(Merck)was incubated at 80ºCfor 4 h for activation. After 30 min of TLC chamber preparation, phospholipidsextracted from C. glabratacells werespotted at thebottom (1.5 cm fromthelowerend) of the
    3. PI-3kinase reaction was set up ina total volume of50μlin a 1.5 ml microcentrifuge tube as described below.PI-3 kinase reaction buffer = 25 μlSpheroplast lysate = 20 μl (equivalent to 10 μg protein)Sonicated phosphatidyl inositol = 5 μlReaction mix was incubated at 25ºC for 20 min and enzyme reaction was stopped by adding 80μlHCL (1N) solution. To extract phospholipids, 160 μl chloroform:methanol (1:1) was added to the reaction mix withcontinuous mixing. Organic phase containing phopholipidswas separated fromaqueous phase by centrifugation at 7,500g for 4 min at 4ºC and transferred to a new vial. Using vacuum evaporator apparatus, solvent was evaporated and phospholipidsweredissolved in 10 μl chloroform
    4. PI-3 kinase reaction set up and phopsholipid extraction
    5. 10 mg phosphatidylinositol-sodium salt(from Glycine max)was dissolved in 2 ml chloroform to prepare a 5 mg/ml stock solution. This solution was prepared in a small glass vial aschloroformis known to reactwith polypropylene. Small aliquots of stock solution were madeand stored at -20ºC till further use. To avoid spillage due to vapor pressure, vials containing phosphatidylinositol-sodium salt solutionwereopened very carefully.To prepare sonicated phosphatidylinositolfor one PI-3 kinase reaction, 2 μlof the stock phosphatidylinositolsolution (10 μg) wastransferredtoanew1.5 ml microcentrifuge tube. Using vacuum evaporator apparatus, chloroformwas evaporated from the solution and phosphatidylinositol-sodium saltwas resuspended in 5 μl sonication buffer.For sonication, a total of 20 pulses, each of 30 sec with30 sec resting time weregiven on ice
    6. A single colonyof desired C. glabratastrainwas inoculated in YPD-liquid mediumand grown for 14-16 h. 50 μl overnight culture was inoculated inYPD-liquid mediumfor 4 h. Log-phase-grownyeast cells were harvested,washedwith PBSandwereinoculated atinitial OD600of 2 and 4,into YNB-dextrose and YNB-sodium acetate liquid medium,respectively.After 4 hincubation,yeast cells were harvested by centrifugation at 2,500g for 5 minand treated with 1.2 M zymolyasefor 1 hto obtain spheroplasts.Post zymolyase treatment, spheroplasts were resuspended in 100 μl resuspension bufferandanequal amount of 0.25 mm glass beadswasadded to lyse the spheroplasts. Using bead beater apparatus, spheroplasts were lysed and protein concentration in spheroplast lysateswas determined usingbicinchoninic acid assay (BCA) method and samples were stored at -20ºC till further use
    7. In vitroPI-3 kinase reactions wereset up to measure PI-3P synthesized as described earlier(Whitman et al., 1988)
    8. Colony blot assay was performed to analyse secretion of carboxypeptidase Y(CPY)as described previously (Roberts et al., 1991). Single colony of a C. glabratastrain was inoculated in YPD medium andculture was grown till stationary phase. 0.1 OD600equivalent cellsfrom this culture were spotted on CAA medium,overlaidwith a nitrocellulose membrane and plate was incubated at30 ̊C for 18-20 h.Afterincubation, nitrocellulose membranewas washed with water to remove cells and membrane-bound CPYwas detected by immunoblotting with polyclonal anti-CPY antibody at a dilution of 1:10,000
    9. was washed three times with PBS to remove non-adherantC. glabratacellsand Lec-2 cells were lysed in 5% SDS. Lysates were transferred totubes containing scintillation fluidand radioactive counts obtained were considered as ‘output values’. Percentage adherence wasdetermined using following formula
    10. Adherence of C. glabratacells toLec-2 epithelial cells wasmeasured as described previously(Cormack et al., 1999).Lec2cells were seeded ina 24-well tissue culture plate at a seeding density of 5X105cells per well and allowed to adhere for 12 h. After 12 h,medium supernatant was discarded by inverting the plate in a reservoir and cells were washed thrice with PBS. Lec2 cells were fixed in 3.7% para-formaldehyde for 15 minfollowed by 2 PBS washes. PBS containing antibiotics, penicillin and streptomycin,was added toeach well of the 24-well plate and Lec-2 cellswere stored at 4°C.For adherence measurement,strains were taken out either on YPD or CAA mediumandgrown at 30°C for 2 days. Single colony of a C. glabratastrain wasinoculated in 10 ml CAA medium ina 100 ml culture flaskand allowed to grow at 30°C for 16-20 h. 100 μlyeast culture wasreinoculated in fresh 5 ml CAA liquid medium in a 15 ml polypropylene tube. 200 μCi of S35(Met:Cys-65:25) INVIVO PROTWIN labelmix(JONAKI, India) was added to thetube and cultures were grown at 30°C for 16-20 h for radiolabeling of C. glabratacells. C. glabratacells from 1 ml culture were harvested and washed threetimes with PBS to remove residual S35(Met:Cys-65:25) labeling mix from medium supernatant. Next,cells were resuspended in 1 ml PBS. OD600was measured and cell suspensions of 0.5 OD600were prepared. PBS was aspirated out of the wells of 24-well plate containing fixed Lec-2 cells. 200 μl of S35(Met:Cys-65:25)-labeled C. glabratacell suspensions were added to each well. To determine the total amount of radioactivity present in labeled C. glabratacell suspension, 200 μl of S35(Met:Cys-65:25)-labeledC. glabratacell suspensions were transferred to a scintillation vial containing scintillation fluid. Radioactive counts present in this fraction were considered as ‘input values’. For measurement of yeast adherence to Lec-2 cells, plates were centrifuged at 1,000g for 5 min and incubated for 30 min at room temperature. Following incubation, each wel
    11. Adherence assay
    12. 20 mg protein samples, isolated from RPMI-grown and macrophage-internalized yeast, were usedto measure KDAC activityusing HDAC Fluorimetric Assay/Drug Discovery Kit (EnzoLifeScience) as per manufacturer’s instructions
    13. For protein extraction, yeast cells were suspended in 50-100μl protein extraction buffer containing 320 mM (NH4)2SO4, 200 mM Tris-Cl (pH 8), 20 mM EDTA (pH 8), 10 mM EGTA (pH 8), 5 mM MgCl2, 1 mMDTT, 10% glycerol and protease inhibitorsand disrupted using glass beads.Cell lysate was centrifuged at 7,500g and4oC for 15 min. 30 μg of total protein was resolved on a 15% SDS-PAGE gelat 32 mA till the dye front reachedthe bottom. Resolved proteins were transferred to Hybond-P membrane at 350 mA for 1.5 h in the cold room.Transfer of the proteins was visually confirmed by examining marker’s lane and membranes wereincubated in a small box for 2 h in 5% fat free milkprepared in 1X TBST for blocking. Blocking solutions were discarded and primary antibody, appropriately diluted in 5% fat free milkprepared in 1X TBST,was added to the box containing membrane. After overnight incubation in primary antibody, membranes were washed thrice with 1X TBST for 10 min. Membranes wereincubated for 2 h inappropriate secondary antibodydiluted in 5% fat free milkprepared in 1X TBST. Blots were either developedby chemiluminescence based ECL-Plus western detection system orChemidocTMgel imagingsystem. CgGapdhwas used as a loading control. To exclude the possibility of any contribution of THP-1 proteins tocell extracts prepared frommacrophage-internalized yeast, two control experiments wereperformed. First, we probedthe blots with antibodies specific for mammalian tubulin and actin.As expected, we neitherdetectedanysignal for mammalian actin nor formammalian tubulin. In the second control experiment, we treated macrophage lysates with proteinase-K prior to the yeast pellet disruptionand probed yeast lysates for different histone modifications.This proteinase-K treatmentdid not alter the epigenetic signature of C. glabratacells.Together, these data indicate that yeast protein samples were devoid ofany mammalian protein contamination
    14. homogenizedin 1 ml PBS and fungal burden was assessed by plating appropriate dilutions of tissue homogenate on YPD plates containing penicillin and streptomycinantibiotics (100units/mlpenicillin and 100μg/mlstreptomycin). All mice experiments were repeated twice with a set of 7-8 mice per strain in each experiment
    15. Experiments involving mice were conducted at VIMTA Labs, Hyderabad.100 l YPD-grown C.glabratacellsuspension(4 X 107cells)was injected into female BALB/c mice (6-8 weeks old) through tail vein. Seven dayspost infection, mice weresacrificedand kidneys, liver,spleenand brainwere harvested. Organs were
    16. Experiments involving mice were conducted at VIMTA Labs Limited, Hyderabad in strict accordance withguidelines of The Committee for the Purpose of Control and Supervision of Experiments on Animals (CPCSEA), Government of India. The protocol was approved by the Institutional Animal Ethics Committee (IAEC) of the Vimta Labs Ltd. (IAEC protocol approval number: PCD/OS/05). Procedures used in this protocol were designed to minimizeanimalsuffering
    17. CgRTT107(3.3 kb),CgRTT109(1.3 kb),CgVPS15(3.4kb) and CgVPS34(2.4kb) ORFs were PCR amplified from genomic DNA of the wild-type strain using high fidelity Platinum Pfx DNA polymerase with primers carrying restriction sites for SmaI-SalI,BamHI-SalI,XmaI-XhoIandSalI-XmaI,respectively.Amplified fragments werecloneddownstream of the PGK1promoterin the pGRB2.2 plasmid. Clones were verified by bacterial colony PCR, sequencing and complementation analysis
    18. After restriction enzyme digestion, digested products wereresolved on agarose gels and desired DNA fragmentswereextracted from the gel. Concentration of gel-extracted DNA fragments was determined usingspectrophotometerand ligation reactions were set up using a molar ratio of vector to insert of 1:3 and 1:1 for sticky and blunt end ligations, respectively. Ligation mixwas incubatedeither at 22ºC for 4 hor at 16°Cfor 14-16 h. After incubation,T4DNA ligase was inactivatedat 65ºC for 20 min
    19. QIAGEN QIAquick PCR purification kit containing buffers, spin columns and collection tubes wasused topurify DNA fragments from PCR andenzymatic digestion reactions as per the kit manufacturer’s instructions
    20. QIAGEN QIAquick Gel extraction kit containing required buffers, spin columns and collection tubes was used to extract and purify DNA from agarose gels. Digested DNA sample was resolved on 1-1.2% agarose gel and gel piece containing desired fragment was cut ona UV-transilluminator. DNA fragment was purified as per the kit manufacturer’s instructions
    21. C. glabratacells grown either in RPMI medium or harvested from THP-1 macrophages were collected, washed with DEPC treated water and were disrupted with glass beads in trizol. Total RNA was isolated using acid phenol extraction method and frozen at -80C. Quality of RNA was examined by determiningtheRNAintegrity number (RIN) before microarrayanalysis.Microarray experiments wereperformed atOcimum Biosolutions Ltd., Hyderabad (http://www.ocimumbio.com). Briefly, a4x44K GE Agilent array comprised of 10,408 probes representing 5,205 ORFs of C. glabratawas used wherein average number of replicates for each probe was four to five. Feature Extraction software version (Agilent) and Quantile normalization was used for data analysis. Hierarchical clustering was performed using Complete Linkage methodwith Euclidean Distance as distance measure. Data arethe average of two hybridizations from biological replicates ofeach sample and raw data sets for this study areavailable at the Gene Expression Omnibus database(Accession number -GSE38953)
    22. To preclude the possibility of human RNA contamination, cDNA prepared from internalized yeast was examined for the presence of human transcripts encoding Ccl5 and histone H3. However,no amplification forhuman genes was observed, thus, eliminating any possiblecontamination of THP-1 RNA with yeast RNA
    23. Primersfor real-timePCR analysisweredesigned using Primer3 plus software and are listed in Table 4. To extractRNA from macrophage-ingested C. glabratacells, infected THP-1cells were washed twice with PBS and lysed in 1 ml ice-cold water. Lysate was centrifuged followed by two quick washes with DEPC-treated water andwashed yeast cell pellets were frozen on dry ice.For RNA extraction, yeast cells were disrupted with glass beads in trizol and total RNAwas isolated usingacid phenol extraction method described above.Optimal primer and cDNA concentrations were standardizedand qRT-PCR was performedusing ABI 7500 Fast Real-Time PCR System (Applied Biosystems).In brief, 0.5 μl cDNA,0.1 to 0.2picomoles of gene specific primers and 10 μl 2X MESA GREENqPCR™ Mastermix Plus containing SYBR green dye (Eurogentec)were mixed in thewellsof a 96-well PCRplate (Axygen). Final reaction volume was adjusted to 20 μl with DEPC-treated water. Transcript levels were quantified with an end-point value known as Ct(cyclethreshold). Expression of TDH3, which encodes CgGapdh,was used asaninternal control. The Ct defines the number of PCR cycles required for the fluorescent signalof SYBR green dye to cross beyondthe background level.Fold-change in transcript expression was determined usingfollowing formula.Fold change in expression = 2-ΔΔCtΔΔCt= ΔCttreated -ΔCtuntreatedΔCttreated = Ctvalue forthe gene of interest under treated condition -Ctvalue forthe internal control gene (TDH3) under treated conditionΔCt untreated = Ctvalue forthegene of interest under untreated condition -Ctvalue forthe internal control (TDH3) gene under untreated condition
    24. Complementary-DNA synthesis was doneusing reverse transcriptase enzyme and oligo-dT primers. For this, 1 μg good quality RNA was treated with1μl(1 unit) DNase I for 15 min to remove DNA contamination. Next, SuperScript III First-Strand Synthesis System kit (Invitrogen) was used to synthesize cDNA according to the manufacturer’s instructions. cDNA synthesized was stored at -20 ̊C till further use
    25. For RNA experiments, all solutions were prepared in RNase free diethylpyrocarbonate (DEPC) water. Microcentrifuge tubes and tips used for RNAworkwere autoclaved twice and driedat 70 ̊C for overnight before use. Non-autoclavable plastic items were wiped with Ambion RNAseZap to remove RNAse contamination, if any. RNA was extracted from C.glabrata cells usingacid phenol extraction method. C. glabratacells were harvested at 2,500g for 5 minat 4 ̊C, resuspended in 1 ml ice-cold DEPC water and were transferred toa2 ml microcentrifuge tube. Cells were spun down at 6,000g for 3 minat 4 ̊C and resuspended in 350 μl AE solution. Next, 50 μl SDS and 400 μl acid phenol(pH 4.5)solutions were added to thetube and mixed well by vortexing. The tube wasincubated at 65 ̊C for 15 min with continuous mixing. After incubation, tube was kept on ice for 5 minand centrifuged at 7,500g for 5 minat 4 ̊C. Aqueous phase was transferred toa new 1.5 ml microcentrifuge tube and RNAwasextracted with an equal volume of chloroform. Total RNA was precipitated at room temperature with 1/10thvolume of 3 M sodium acetate (pH 5.2) and 2.5 volumesof chilledabsolute ethanol for 20 min. Precipitated RNA was collected by centrifugation at 7,500g for 5 minat 4 ̊C. RNA pellet was washed with chilled 70% ethanol and resuspended in 50 μl nuclease-free water. RNA concentration was determined by measuring absorbance at 260 nm. Quality of extracted RNA was examined by gel electrophoresis on 0.8% agarose gel prepared in DEPC-treated TAE buffer
    26. Nucleosomal-associated DNA was extracted from RPMI-grownand macrophage-internalized C. glabratacells using EZ NucleosomalDNA prep kit (ZYMO Research),treated withmicrococcal nuclease digestionfor 2.5, 5, 7.5 and 10 min at 25ºC andwasresolved on 2% agarose gel
    27. temperature. Genomic DNA pellet was dissolvedeitherin 50 μl 0.1X TE or molecular biology grade water containing 0.3 μlAmbion RNAse cocktail and incubated at 37ºC for 30 min.After RNA digestion, 100 μl of 0.1X TE or nuclease-free water was added to the tube and stored at -20ºC. Quality of extracted genomic DNA was checkedon 0.6% agarosegel by electrophoresis
    28. Desired C. glabratastrain wasgrownovernight in YPD liquid medium and yeast cells were harvested by centrifugation at 2,500g in 15 ml polypropylene tube.Yeast cells were washed with PBS, resuspendedin 500μl lysis buffer (Buffer A) andwere transferred toa2ml microcentrifuge tube. Yeast cells were incubated for 15 minon a thermomixer set at 65 ̊C and 750 rpm. After incubation, 0.5 gm glass beads (0.5 mm) and 500 μl PCI solution were added to thetube. Yeast cells were lysedthree times for 45 seconds each on a bead beating apparatus with intermittent cooling on ice to prevent overheating. Cell lysates were centrifugedat 7,500gfor 5 minandupperaqueous phase (300-350 μl) wastransferred carefully to a new 1.5 ml microcentrifuge tube. 1 mlabsolute ethanol was added andmixedwellby inverting the tube3-4 times. To precipitate genomic DNA, suspension was centrifuged at 7,500g for 10min.Precipitated genomic DNA was washedwith 70% ethanolanddried at room
    29. C. glabrata cells were grown overnight in 10 ml YPD liquid medium. Cells were harvested at 2,500g for 5 min, resuspended in 400 μl Buffer A (50 mM Tris-HCl, 10 mM EDTA, 150 mM NaCl, 1% Triton X-100 and 1% SDS) and were transferred to a 2 ml microcentrifuge tube. Equal volume of phenol-chloroform-isoamyl alcohol (PCI) solution was added tocell suspension and tubes were vortexed for 2-3 min. After incubation at 42 ̊C for 30 minon a thermomixer set at 800 rpm (Eppendorf), cell debris was removed by centrifugation at 7,500g for 10 minand aqueous phase (300-350 μl) was carefully transferred to a new 2 ml microcentrifuge tube. Genomic DNA was precipitated with800 μl chilled absolute ethanol and 35 μl sodium acetate (3 M, pH 5.2). DNA pellet was washed with chilled 70% ethanol and dried at room temperature for 5-10 min. Genomic DNA pellet was dissolved either in 50 μl 0.1X TE or molecular biology grade water containing 0.3 μl Ambion RNase cocktail and incubated at 37 ̊C for 30 minfor digestionof RNA. After RNA degradation, 100 μl of 0.1X TE or nuclease-free water was added to the tube and stored at -20ºC. Quality of extracted genomic DNA was checkedon 0.6% agarosegel by electrophoresis
    30. Stripping of membranes in buffer containing 0.4 M NaCl yielded slightly better results. Hybond membranes were reused for 5-10 times after stripping
    31. Radiolabeled-bound probes were stripped from the membrane by boiling in 1% SDS containing 0.1X SSC for 15 min. Alternatively, membraneswereincubatedtwicein stripping solution (0.4 M NaOH)at 45°C for 30 minto remove the bound probes
    32. After 2-3 h exposure,phosphorimagerscreenwas scannedon Fuji FLA-9000 to acquire hybridization images. Next,signal intensity for each spot on the membrane for both input and outputsampleswas quantifiedusing Fuji Multi Gauge V3.0 software andpercentage intensity foreach spot relative tothe whole signal intensity ofthe membranewas determined.To identify mutants with altered survival profiles,ratio of output (Op) to input (Ip) signal for each spot (oligonucleotide tag)present on the membranewas calculated.Mutantsdisplaying at least 6-fold higher and 10-fold lower survival were selectedas “up’ (Op/Ip= 6.0) and ‘down’ (Op/Ip = 0.1) mutants, respectively
    33. After14-16 hincubation, hybridization buffer was decanted to a radioactive liquid waste container.Membraneswere washedtwice with 2X SSC (saline-sodium citrate) containing 0.1% SDS for 15 min at 55°C followed by two washes with 1X SSC containing 0.1% SDS for 15 min at room temperature. Post washes,membranes were rinsed with 1XSSC buffer at room temperature and exposed to phosphorimager screen for 2-3 h
    34. Primers (OgRK 25 and OgRK 26, 200 pM ) –1 μl, eachTaq DNA polymerase –0.5 μlαP32-dCTP( specific activity-3,000 Ci/mMol)–2.5 μlWater –38.5 μlαP32-dCTPlabeled PCR productswere denatured by incubatingtubesat100°C for 5 min followed by immediatechilling on ice. After 2 h prehybridization, radiolabeleddenatured input and output probes were added to respective bottles and bottles were transferred to a hybridization oven set at 42ºC and 6 rpm
    35. Two Hybond-N membranes,each carrying 96 immobilized DNA with unique signature sequences,were transferred to 15 cm long hybridization bottlesandlabeledas input and output. 10 mlprehybridization buffer was added to each bottle and bottles were transferred to a hybridization oven setat 42ºC and 6 rpm. To prepare input and output probes,genomic DNAsfrom input and output C. glabratacell pelletswere extracted using glass bead lysismethodandunique signature tags were PCR amplifiedwith nucleotide mix containing αP32-dCTP using primerscomplementary to the invariant region flanking each unique oligonucleotide sequence.Following is the composition of50 μlPCR cocktail used to prepare radiolabeledinput and output probes.10X PCR buffer–5 μldNTP mix (without dCTP, 2mM) –0.5 μldCTP (0.05 mM) –1 μl
    36. E. colistrains containing plasmids with unique oligonucleotide signature sequences were inoculated in LBmedium containing ampicillin and grown overnight at 37°Cand 200 rpm. Plasmids were extracted, quantitated anddenatured in alkaline denaturing solution. Approximately, 200 ng of each plasmid DNA was transferred to theHybond-Nmembraneusing96-well Dot Blot apparatus. Membranes were neutralized in 2X SSC and denatured plasmids were cross-linked to Hybond-N membranes usingUV cross linker
    37. E. colistrains carrying plasmids were inoculated and grown overnight at 37ºC and 200 rpm in LB-liquid medium supplemented with either 50 μg/ml ampicillinor 30 μg/ml kanamycin. Cells were harvested by centrifugation at 2,500g for 5 min. Plasmids were extracted using Qiagen plasmid miniprep kit following the manufacturer’s instructions. Concentration of the extracted plasmid DNAs was measured using spectrophotometerat 280 nmandstored at -20ºC
    38. Genomic mapping of disrupted locusin Tn7insertion mutants was carried out as describedpreviously(Kaur et al., 2004).C. glabratamutants carrying Tn7insertionswere grown in YPD-liquid medium and genomic DNA was isolated fromovernight cultures. 10 μg genomic DNA was digested either with restriction enzyme MfeIor SpeI.Restriction enzyme-digestedDNA was precipitated with 1 ml ethanol and 1/10thvolume of sodiumacetate (3 M,pH 5.2). DNA pellet was washed twice with ice-cold 70% ethanol, air driedand was resuspended in sterilewater. DNA was recircularized with T4 DNA ligase.Resultant circular DNA carriedTn7cassette flanked on bothsidesby the disrupted locus oftheC. glabratagenome. CircularDNA wastransformed in E. coliBW23473 strainwhich contains protein Π (the product of the pirgene) required by R6Kγorifor replication.Twoverified transformants were grown overnight in LB-kanamycin medium and plasmids were extracted. Purified plasmids were sequenced withprimers reading outwards (OgRK 183 and OgRK 184) from both ends ofTn7cassette.Sequences obtained were compared,usingBLAST,against C. glabratagenome sequence database and regionsof Tn7insertions in C. glabratawere mapped
    39. E. coli BW23473 electro-competent cell aliquots were taken out from -70ºC freezer, thawed on ice and were mixed with 1-2 lplasmid DNA. Mixture was pulsed with the Gene Pulser® electroporation apparatus (Bio-Rad),set at 1800 Volts, 25 μF and 200 Ω,in a chilled 0.1 cm electroporation cuvette. After electric pulse, 1 ml LB medium was immediately added to the cuvette and suspension was transferred to a 1.5 ml sterile microcentrifuge tube. Cells were incubatedat 37°C and 200 rpm for 1 h, centrifuged and were plated on LB-agar plates containing kanamycin (30 μg/ml). Transformants were colony purifiedon LB-kanamycin plates. Positive clones were verified by colony PCR and inoculated in LB-liquid medium containing kanamycin (30 μg/ml) for plasmid isolation
    40. To prepareelectrocompetent cells, a single colony of E. coli BW23473 strain from a freshly-streaked LB agar plate was inoculated in 50 ml LB liquid medium. Culture was incubated at 37°C for 14 h with continuous shaking at 200 rpm. 25 mlovernight-grown E. coliBW23473 culture was transferred to 500 ml LB liquid medium and incubated at 37°C till the OD600 reached to 0.4. Post incubation, cultures were transferredto ice and centrifuged at 1,000g for 15 minat 4°C. Cells were washed twice with 500 ml ice-cold sterile water, three times with 250 ml ice-cold 10% glycerol solution and resuspended in 1 ml 10% glycerol solution. After absorbance measurement, cell suspension was normalized to final cell density of 3X1010cells/ml and dispensed in 50 μl aliquots to sterile ice-cold 1.5 ml microcentrifuge tubes. Aliquots were snap frozen in liquid nitrogen and stored at -70ºC
    41. E. coliDH5α strain was transformed with plasmids carrying appropriate inserts to clone and generatedeletion strains of C. glabrataORFs(Sambrook, 2001). Ultracompetentcells stored at -70⁰C were thawed on icefor 5-10 min. 5 μlligated plasmid was added to100 μlultracompetent cells andcells were incubatedon ice. After 30 min, competent cells were subjected to heat shock at 42⁰C for 90 seconds. Cells were immediately transferredtoicefor 2-3min. Next, 800 μlSOC (or LB) medium was added and cells were allowed to recover for 45 minon a shaker incubator set at 37⁰C.After the recovery, cells were centrifuged at 2,500g for 4 min. Medium supernatant was discarded and cells were resuspended in 200 μlfresh sterile LBmedium. Cells were plated on LB agar medium containing appropriate antibiotics. Plates wereincubatedat37⁰C for 12-16 h
    42. 10 min at 4 ̊C and gently resuspended in 20 ml ice-cold Inoue transformation buffer. To this cell suspension, 1.5 ml sterile DMSO was added and swirled gently. Cell suspension was kept on ice for 10 min and 50 μl volume was aliquoted to chilled sterile microcentrifuge tubes. Cells were immediately snap-frozen in liquid nitrogen and stored at -80 ̊C
    43. A single colony of E. coli DH5α strain was inoculated in 10 ml LB medium and incubated at 37 ̊C for overnight. 4 ml overnight culture was inoculated in 2 lt SOB medium and incubated at 18 ̊C till the OD600 reached to 0.5. Cultures were centrifugedat 2,500 g for 10 min at 4 ̊C and harvested cells were washed gently with80 ml ice-cold Inoue transformation buffer. Cells were collected by centrifugation at 2,500 g for
    44. A microtipful of cellsfor each yeaststrainfrom appropriate mediumwassuspended in 10μlzymolyase cocktailandincubated at 37ºC for 90 min. 2 μlof zymolyase-treated cell suspension was used as template in 25 μlPCR reaction
    45. Alipophilic styryl dye,FM4-64,is a vital stain which istakenupby cells viaendocytosis through plasma membrane(Vida and Emr, 1995). Therefore, it fluorescesonly in live cells. Importantly, neitherfixed cells canbe stained with FM 4-64norcells canbe fixed afterFM 4-64staining. For vacuole staining, single colony of the test strain grown onYPD plate was inoculated in 10 ml YPD medium for overnight. 100 μlovernight culture was inoculated in fresh YPD medium and incubated at 30ºC for 3 hto obtain log-phase cells. C. glabratacells from 1 ml log-phase culture were harvested at 4,000 rpm for 5 minin a table top centrifuge. Supernatant was aspirated out,cells were resuspended in 50 μl YPD medium and 1 μl FM 4-64 (16 μM final concentration) was added.C. glabratacells were incubated in a 30ºC water bath for 30 min. 1 mlYPD medium was added and cells were harvested at 4,000 rpm for 5 minin a table-top centrifuge. After discarding supernatant,C. glabratacells were washed with fresh YPD medium and resuspended in 1 ml YPD medium. C. glabratacells were incubated at 30ºC for 90 min, washed with 1 mlsterile water and were resuspended in 50 μl YNB medium. Labeled C. glabratacells were observed underfluorescence microscope in red filter(730nm)
    46. centrifugation at 5,000 rpm for 4 minat room temperature. Harvested cells werewashed with PBS and treated with different compoundse.g.H2O2. After treatment,cells were harvested and further processed according to the type of experiments performed
    47. For several experiments, log-phase C. glabratacells were harvested and treated with different compounds. For this, single colony of aC. glabratastrain was inoculated in YPD-liquid medium and grown for 14-16 h at 30ºC withcontinuous shaking at 200 rpm. Overnight cultures were reinoculated in YPD medium to an initial OD600of 0.1 andgrown for another 4 h. These log-phase cells were harvested by
    48. For opsonization,C. glabratacells were incubatedwith 1 μg/μl human IgG for 30 min at 37°C and washed thrice with PBS. Alternatively, yeast cells were incubated with 25% human serum at 37°C for 30 min followed by threePBS washes
    49. C. glabratastrains were grown overnight in YPD medium. Cellswereharvested from 1 mlcultureandwashed withPBS.Cells were next washed with50mM NaH2PO4andresuspendedin 100 μlFITC-dextran(50mg/ml). After incubation at 37°Cfor 45 min, cells were washed thrice with PBS for complete removal of FITC-dextran.Yeast cells were resuspended in 1 ml PBS and used to infect PMA-treated THP-1 cells in 4-chambered glass slide
    50. 24 h post infection, THP-1 macrophages were washed thrice with PBS, lysed in water and recovered yeast cells were used to infect THP-1 cells at a MOIof 1:10. Three rounds of macrophage infection foreach mutant pool were carried out to enrich for the desired mutants in the final population. The lysate of 3rdround infection was inoculated in YPD medium for overnight (output). Cells were harvested, genomic DNA isolated from each input and output cell pellet andunique signature tags were PCR-amplified with P32-labeledα-dCTP using primers complementary to theinvariant region flanking each unique tag sequence. LabeledPCR products were denatured at 95°C for 10 min, chilled on ice and were hybridized tonylon membranescarrying immobilized plasmid DNA containing 96 unique tagsfor 14-16 h at 42°C.Membranes were washed twicewith 0.1X SSC bufferand exposed to phosphorimager screen for 2-4 h. Radioactive counts for each spot were quantified using Image Quant and Fuji Multi Gauge V3.0 software. Relative percentage intensity for individual spot was calculated with respect to allspots present oneach hybridizedmembrane
    51. YPD-grown cultures (0.05 OD600) of each mutant pool (96 mutants, each carrying a unique signature tag) were either inoculated in YPD medium for overnight (input) or used to infect differentiated THP-1 cells (1X106). After 2 h incubation, non-cell-associated yeastcellswere removed by washing THP-1 cellsthricewith PBS. At
    52. Single colony of C. glabratastrains wasinoculated in 10ml YPD-liquid medium and grown at 30°C with constant shaking at 200 rpm for 14-16 h. Overnight culture was used to inoculate 10 ml YPD broth to an initial OD600of 0.1 and culture was grown for 4-5 h to obtain log-phase culture. Log-phase C. glabratacells were harvested in 15 ml sterile polypropylene tubesby centrifugation at 4,000 rpm for 5 min. Harvested cells were washed with10ml sterile water,resuspendedin 1 ml sterile water and transferred to a 1.5 ml microcentrifuge tube. Cells were harvested at 4,000 rpm for 5 minand resuspended in 100 μl of100mM lithium acetate solution.Yeast transformation cocktail was prepared in a 1.5 ml microcentrifuge tube by mixing 240 μlpolyethylene glycol(50%), 36μl lithium acetate(1 M) and25μlheat-denatured single stranded carrier DNA(2 mg/ml). 50 μlC. glabratacell suspension and 50 μltransforming DNAwas added to the transformation cocktail, mixed well andincubatedat 30 ̊C for45 min. 43 μlDMSO was added and cells were subjected to heat shock at 42 ̊Cfor 15 min. After the heat shock, cells were transferred to ice for 10-15 seconds, centrifuged at 4,000 rpm for 5 min and supernatantwas removed.Cells wereresuspended in 200 μlsterile water andspread platedonappropriate selectionmedium. Plates wereincubatedat30 ̊Cfor 2-3 days
    53. Identified mutants were phenotypically characterized in 96-well plate format. Mutant cultures were grown in YPD medium for overnight, diluted 150-fold in PBS and 5 μl of cell suspension was spotted on different plates with a 96-pin replicator. Growth was recorded after 1-2 daysof incubation at 30°C
    54. at 30°C andimages were captured after 2-8daysof incubationdepending upon the medium used
    55. Yeast strains were grown in YPD medium for 14-16 hat 30°Cunder continuous shaking at 200 rpm. Cells were harvested from 1 mlculture, washed with PBS and were diluted to an OD600of 1. Five ten-fold serial dilutions were preparedfrom aninitial culture of 1OD600.4 μl cultureof each dilution was spotted onYNB-agar plates containing different carbon sources. For spotting on YPD plates containing different compounds, 3 μl cultureof each dilution was spotted. Plates were incubated
    56. For growth analysis of a C. glabratastrain,single colony wasinoculated in appropriate broth medium and grown for 14-16 h. Overnight grown culture was used to inoculate the test medium toan initial OD600of 0.1-0.3. Cultures were transferred to a shaker incubator set at 30°C and 200 rpm. Absorbance ofcultures was measured using Ultraspec 2100 pro UV/visible spectrophotometer (Amersham Biosciences) at 600 nm at regular time-intervalstill 48h. Absorbancevalues were plotted with respect to time and generation time was determined from the logarithmic (log)phase of cell growth usingthefollowing formula.G = Generation time (h)T1= Initial time point taken for analysisT2= Final time point taken for analysisNf= Number of cells at time T2(1 OD600of C. glabrata corresponds to 2 X 107cells.)Ni= Number of cells at time T1(calculated from OD600value as mentioned above)
    57. C. glabratastrains were routinely grown either in rich YPD medium or synthetically-defined YNB medium at 30°C withcontinuous shaking at 200 rpm unless otherwise stated. In general, C. glabratafrozen glycerol stocks wererevivedonYPD medium by streaking and allowed to grow for 1-2 days. C. glabratastrainsharboringthe plasmid with URA3as selectable marker were revived onCAA medium.To prepare liquid cell culture, single colony of eachC. glabratastrainwasinoculated either in YPD or YNB broth mediumand grown for 14-16 h. C. glabratastrains streaked on plates were storedat 4°C fora maximum period of2 weeks
    58. To collectmacrophage-internalized yeast cellsfor RNA and protein extraction, 107THP-1 monocytes were seeded in 100 mm cell culture dishes and treated with PMA. PMA-differentiated THP-1 macrophages were infected with appropriateC. glabratastrainsto a MOIof 1:1. Equal numberof C. glabratacells wasinoculated inRPMI medium as control. Two hourspost infection,non-phagocytosed yeast cells were removed by washing THP-1 macrophages thrice with PBS. At different time points, culture dishes were washed twice with chilled PBS and 2 mlchilled sterile water was added toeach dish to lyse the macrophages. Corresponding cultures grown in RPMI medium were transferred to50 ml polypropylene tubesand transferred on ice. Lysates were collected by scrapping the macrophage monolayer and transferred to50 ml polypropylene tubes.RPMI-grown and macrophage-internalized C. glabratacells were harvested by centrifugation at 2,500g for 8 min. Macrophage cell debris were removed frommacrophage-internalized cells by repeated washing with chilled sterile water. Harvested C. glabratacells were stored at -20ºC till further use
    59. undertissueculture conditionsfor 45-60min andfixed in 3.7% formaldehydeas described earlier.For DAPI staining, Vectashield mounting medium containing DAPI was used and slides were visualized under confocal microscope.For heat killing, yeast cells were harvested from 1 ml culture, washed, resuspended inPBS andwere incubated at 95°C for 5 min
    60. PMA-treated THP-1 macrophages were infected with C. glabratacells to a MOIof 1:1 in four-chambered slides and incubated at 37°C and 5%CO2. After 1 hcoincubation, each chamber was washed thrice with PBS to eliminate extracellular yeast cellsand medium was replaced with fresh prewarmed RPMI medium containing100 nM Lysotracker Red DND-99.Infected THP-1 macrophageswere incubated
    61. For confocal microscopyanalysis, 5X105THP-1 cells were seeded and treatedwithPMA in 4-chambered slides. Differentiated THP-1 macrophageswere infected either with FITC-labeled or GFP-expressingC.glabratastrains to a MOIof 1:1. At different time intervals, medium was aspirated out from each chamber of 4-chambered slides and chamberes were washed twice with PBS. To fixthe infected macrophages,500 μlformaldehyde(3.7%) was added gently toeach chamber andincubated for 15 minat room temperature. Each chamber of the slide was washed twice withPBS to remove formaldehyde solution completely. To permeabilize the fixed cells, 500 μl Triton-X (0.7%) was dispensed toeach chamber and slide wasincubated at room temperature for 5 min. Chambers of the slide werewashed twice with PBS, separated from the slideusing a chamber removal device andwere air dried. Coverslips were placed onslides using Vectashield mounting mediumand bordersweresealed withnail paint. Slides werestored at 4°C until used forfluorescence imaging
    62. THP-1 cells were seeded ina 24-well tissue culture plate to a celldensity of 1 million cells per well,treated with PMA and were infected with yeast cells to a MOIof 10:1. Two hours post infection, cells were washed thrice with PBS and medium was replacedwith fresh prewarmed RPMI medium.Plates wereincubatedat 37ºCfor 24 h. Supernatants were collected,centrifuged at 3,000 rpm for 5 minto get rid of particulate matter,if any, andwerestored at -20°C until use. Estimation of different cytokines wasperformed using BD OptEA ELISA kits as per the supplier’s instructions
    63. Forinfection of THP-1 cells with single C. glabratastrain, PMA-treatedTHP-1 monocytes were seeded in 24 wellcell culture plate toa seeding density of 1 million cells per well. To prepare C. glabratacells for macrophage infection, single colony of the desiredstrain wasinoculated in YPD medium and allowed to grow for 14-16 hat 30°C. C. glabratacellsfrom 1ml overnight culture were harvested, washed with PBS andcell density was adjustedto 2X107cells/ml.50 μl of thisC. glabratacell suspension wasinfectedto macrophages to a MOIof 10:1. Two hours post infection, infected THP-1 macrophages were washed thrice with PBS to removenon-phagocytosed yeast cells and medium was replacedwith fresh prewarmed medium. Atdifferent time points post infection,infected THP-1 macrophages were washed with PBS three timesandlysed in 1 mlsterilewater. Lysates were collected by scrapping the wells with a micropipette tip, diluted in PBS and appropriatelysatedilutions were platedon YPD agar medium. Plates wereincubated at 30°C and colony forming units (CFU) were counted after 1-2 days. Final CFUs per ml were determined by
    64. multiplying CFUs with dilution factor and fold-replication was determined by dividing the CFUs obtained at 24 h time-point by 2 h CFUs
    65. THP-1 monocytes were treated with phorbol myrsitylacetate (PMA) to differentiate them to macrophages(Tsuchiya et al., 1982). For PMA treatment, THP-1 cells grown upto 70-80% confluencewere harvested from the culture dishes at 1,000 rpm for 3 min. Harvested THP-1 cells were resuspended in 5-10 ml fresh and prewarmed complete RPMI medium. 100μlof thiscell suspensionwasappropriatelydilutedinPBS and numberof viable cells was determined by trypan blue stainingusing hemocytometer. Cell suspension was diluted with prewarmed RPMI medium to a final density of 106cells/ml. PMA was added to this THP-1 cell suspension to a final concentration of 16 nM and mixedwell.PMA-treated THP-1 cellswere seeded either in 24-well cell culture plate or culture dishes and transferred to the incubator set at 37°C and 5%CO2.After 12 hincubation, medium was replaced with fresh prewarmed medium and cells wereallowed to recover for 12 h
    66. weretransferred toa sterile 100 mm cell culture dishcontaining 11 mlfresh and prewarmed completemedium andculturedin tissue culture incubatorat37°C and 5% CO2.After 12hincubation, medium was replacedwith fresh prewarmed mediumand cells were allowed to proliferate till they acquire 80% confluence
    67. Freezer stocks of THP-1 and Lec-2 cells were prepared either in commercial cell preservation medium (Gibco) or completemedium supplemented with 10%heat inactivated serum and 10% DMSO. For cryopreservation, 5-6 million cells were resuspended in 0.5 mlfreezing medium in 2 ml cryopreservation vials,stored in an isopropanol bath and were transferred to-70°C freezer. Aftertwo days, freezer stocks were transferred to liquid nitrogen containertill further use. To revive the cells, freezer stocks were taken outfrom liquid nitrogen container and transferred immediately to37°C water bath. After2-3 min, when freezing medium hadthawed completely,cells