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  1. Jun 2019
    1. All experiments were carried out on a Beckman XL-A analytical ultracentrifuge, equipped with absorbance optics, and an An60-Ti rotor, at 20 °C. Sedimentation velocity experiments were performed at 40,000 rpm. Data were collected at 540 nm and at a spacing of 0.005 em with three averages in a continuous scan mode. The protein concentration varied in the range 4-40 IJ.M (heme) in 50 mM phosphate buffer, pH 7.2
  2. May 2019
    1. and fixed with 100μl of fixative solution per well, for 10 minutes at room temperature. The cells were then washed twice with PBS and 100μl of staining solution was added to each well. The plate was kept at 37° C, until the color development.
    2. 4x103-5x103 cells were plated in 96 well plate, well. Cells were transfected with reporter plasmid 18 -24 hrs after plating. After 48 hrs, cells were washed once with PBS
    3. 1X PBS diluted in distilled water 1X fixative solution diluted in distilled water Staining Solution25 μl Solution A 25 μl Solution B 25 μl Solution C 125 μl 20 mg/ml X-gal in DMF
    4. 20 mg/ml X-gal in dimethylformamide Solution A as 40 mM potassium ferricyanide. Solution B as 40 mM potassium ferrocyanide. Solution C as 200mM magnesium chloride. 10X fixative (20% formaldehyde; 2% glutaraldehyde in 10X PBS) 10X PBS as 0.017 M KH2PO4, 0.05 M Na2HPO4, 1.5 M NaCl, pH 7


    5. This protocol is for the detection of β-gal expression in fixed cells. It was performed on 96-well plates for initial screening of tTA transfected clone, and is a modification of Sanes et al., 1986
    1. (ii) Stacking gel buffer: 1.0 M Tris-Cl pH 6.8 (iii) Resolving gel buffer: 1.5 M Tris-Cl pH 8.8 (iv) SDS stock: 10% (w/v) solution (v) Ammonium persulphate (APS) stock: 10% (w/v) solution made fresh (vi) Gel running buffer (1X) (vii) Loading dye (6X): (viii) Lysis buffer (RIPA) Gels of 1.5 mm thickness were cast in the Biorad small gel apparatus. Resolving gel of 10% (10 ml) was made by mixing 4.2 ml 10% acrylamide, 3.1 ml water, 2.5 ml of 1.5 M Tris-Cl pH 8.8 and 0.1 ml of 10% SDS. Stacking gel (2 ml) was made by mixing 0.33 ml of 30% acrylamide, 1.4 ml of water, 0.25 ml of 1 M Tris-Cl pH 6.8 and 0.02 ml of 10% SDS. Gels were polymerized by the addition of TEMED (N,N,N′, N′-tetramethyl ethylene diamine) and APS (1/100th volume of gel mix). Sample preparation for gel loading was done as follows. Mid log and late log phase 10 ml cultures were centrifuged at 26000g and the cell pellet was resuspended in 0.5 ml RIPA buffer. Cells were sonicated on ice for 1 min at output power of 5 to get a cleared lysate. The culture lysate was centrifuged at 26000g to recover the clear supernatant. Total cell protein was quantified in the lysates using BCA kit reagents (BioRad) using the manufacturers protocol. Appropriate volume of cell lysate was mixed with the loading dye in a final concentration of 1X and loaded onto the gel. The gel was run at constant voltage of 60 V for stacking and 80 V for resolving gel
    2. The method followed was as described in Sambrook and Russell (2001). The following solutions were used to cast and run SDS-PAGE gels. (i) Acrylamide stock: 29% (w/v) acrylamide and 1% N,N′-methylene bisacrylamide
    3. the phage (λ1098 for Tn10dTet transpositions and λNK1324 for Tn10dCm transpositions) at a multiplicity of infection (moi) of 0.05 in the presence of 5 mM MgSO4. This mixture was incubated for 15 min at 37°C to allow for phage adsorption. The unadsorbed phage was then removed by centrifugation and the pellet was resuspended in 10 ml of LB broth containing 5 mM sodium pyrophosphate. It was incubated without shaking at 37°C for 30 min for phenotypic expression. The rest of the mixture was diluted into 100 ml of LB broth with 5 mM sodium pyrophosphate carrying the required antibiotic and amplified overnight by growth at 30°C. This population of cells was used as a source of random transposon insertions. The λ lysates used for the transposition experiments carry amber mutations, and were propagated on a supE strain C600 by the protocol described below in section 2.14
    4. The method used was essentially the same as that described by Miller (Miller, 1992). The strain to be used for obtaining random Tn10dTet or Tn10dCm insertions was grown overnight in Z-broth containing 0.4% maltose. The culture was then diluted 50-fold in the same medium and grown to an A600 of 0.8. Two ml of the culture was infected with 107 pfu of
    1. 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
    1. 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
    2. 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
    3. 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
    4. 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
    1. Retroviral based system was used for silencing of PTEN. BOSC23 packaging cells were grown in 100 mm culture dishes upto 80-85% confluency. Retroviral RNA vector containing either scrambled control shRNA or pool of PTEN shRNA along with a PCL-Ampho helper plasmid were co-transfected using Lipofectamine 2000 reagent to generate viral particles. After 48 h, supernatant containing viral particles were used to infect MDA-MB-231 cells in the presence of polybrene (8g/ml). For p53 gene knockdown, TP53 mission shRNAs obtained from Sigma Aldrich (St Louis, MO, USA) were transfected using Lipofectamine 2000 (Invitrogen, USA) and non-targeting shRNAs (Sigma) were used as controls. The cellular homogenates were prepared 36-48 h post transfection and were subjected to immunoblotting to check the levels of protein knockdown
    1. labelled RNAs to N+Hybond membrane (GE Life Science), the radiolabelled rRNA was detected using a phosphorimager (Fuji Film FLA-9000)
    2. Overnight grown yeast were sub-cultured at 0.2 OD600and growntill 0.8 OD600.Cells equivalent to 1 OD600were harvested and were washed in SC-Ura medium, suspended in 1 mL of SC-Ura medium containing 3μCi/mL of [14C]uracil and pulselabelledfor 15 min at30°C.After incubation the cells were pelleted and a chase was performed by adding SC medium containing 240 mg/L unlabelled uracil. Samples were taken at 0, 1, 5, 10and 20min after the chase, centrifuged at 12000 x gfor 1 min at 4°C, and total RNA was isolated from cells by the hot-phenol techniquedescribed in Section 2.2.8.Equal total RNA was loaded on a 1.2% formaldehyde-agarose gel. After transfer of
    1. Cells (HEK293T) were transfected with various combinations of plasmids/siRNAsor treated with cisplatin. Cells were washed first with 1X PBSand then with Met-/Cys-1X DMEM supplemented with dialyzed FBS(10%). Cells were then incubated with Met-/Cys-DMEM supplemented with dialyzed FBS in the incubatorfor 1h (met/cysstarvation). Cells were taken out from the incubator,and the culture media was removed. Cells were placed behind the radioactivity protective shield and DMEM supplemented with 35S met/cys (200μCi) was added to the cells. Plates containing radioactive media were then put into the acrylic box and incubated for 1h at 37°C in a CO2 incubator. Plates were taken out and kept behind the radioactivity protective shield;the radioactive media was disposedofin the radioactive liquid waste. One set of cells washarvested for 0 time point, other sets of cells were washed twice with 1X PBS and were incubated with normal medium containing 2mM each of cysteine and methionine. Cell plates were put in the acrylic box and incubated at 37°C in a CO2 incubator. Cells were harvested at different time points. Cells were collected in ice-cold PBS and were lysed using the standard cell lysis protocol. Cell lysate were subjected to immunoprecipitation(IP). IP complex is separated on SDS-gel using standard protocol. The gel was transferred onto PVDF membrane, and the membrane was dried. Dried membrane was exposed in a cassette and the signal was detected using phosphorimager. Later the same blots were probed with specific antibodies
    1. Ferric-iron-reduction activity of Xanthomonas oryzaepv. oryzicolawas measured using ferrozine, a chromogenic ferrous iron chelator, as described previously (Velayudhan etal., 2000; Worst et al., 1998). For estimating the ferric reductase activity, Xanthomonas oryzaepv. oryzicolastrains were grown in 20 ml PS medium carrying appropriate antibiotics for 24 h to OD600 of 1. Cell free PS media was incubated under similarcondition to be used as control. Chromogenic ferrous iron chelator, ferrozine was added to a final concentration of 1 mM, and FeCl3was added as ferric iron source to a final concentration of 50 μM, and incubated at 28ºC. At regular time intervals, 1 ml aliquotes were taken from the test culture and control, centrifuged to remove the cells, and absorbance of the magenta coloured Fe2+-ferrozine complex in the cell free culture supernantant was measured at 535 nm by using control supernatant as reference. The Fe2+reduction activity was quantified as micromoles of Fe2+-Ferrozine complex formed
    2. respectively. The resulting constructs pRR14 and pRR15 were transferred in E.coliDH5α. Through triparental mating using pRK600 helper plasmid the construct were transferred in E.coliS17-1. After confirming pRR14 and pRR15 constructs by sequencing, the constructs were then introduced into BXOR1 strain through biparental mating using E. coliS17-1. X. oryzaepv. oryzicolaGUS and GFP reporter strains were selected on PS medium plates containing suitable antibiotics. Since pVO155 cannot replicate in X. oryzaepv. oryzae, ampicillin and kanamycin-resistant colonies were obtained upon chromosomal integration of the plasmid using the cloned DNA sequence as a region of homology. pProbeGTcan replicate independently in Xanthomonasand report for the gene expression
    3. Glucuronidase (GUS) reporter gene fusion and GFP reporter fusion was created by using the suicide plasmid pVO155 having a promoterless gusAgene (Oke and Long, 1999), and pProbeGThaving a promoterless GFP (Miller et al., 2000). To construct the xsuA::gusAand xsuA::gfptranscriptional fusion, a 611-bp DNA fragment containing the putative promoter of the xssoperon (+213 to −398) was amplified by using the SCRsid_ pProbeGFP_F and SCRsid_ pProbeGFP_R primers (Table 2.2). This promoter fragment was subsequently digested with HindIII and BamHI,and directionally cloned upstream of the promoterless gusAand gfpgene in pVO155 and pProbeGTplasmids to create the xsuA::gusAand xsuA::pProbeGT(gfp) reporter constructs pRR1
    1. To perform immunoblotting or western blotting, appropriate amounts of total protein(ranging from 20-40 μg) were separated ona SDS-PAGE gel of 12%acrylamide concentration in Tris-Glycine-SDS gel running buffer. Protein separation was done at 70-100 V for 2-3 h using a MINI PROTEAN®3 electrophoresis unit (Bio-Rad). Followingseparation, proteins weretransferredto polyvinylidene difluoride (PVDF) membrane, using a Bio-Rad Mini Trans-Blot electrophoretic transfer unit in Tris-Glycine transfer buffer at 4⁰C. Before setting transfer assembly, PVDF membrane was first activated in 100% methanolfollowedby washesin the transfer buffer. The transfer assembly was set inaBio-Rad Mini gel holder cassette (170-3931)according to manufacturer’s instructions. The transfer time and current settings varied depending on the size oftheprotein of interest. Post transfer, membranes wereseparated from the assembly and kept for blocking intheblocking buffer (0.1 % Tween-20, 5% w/v fat-free skimmed milk in 1X TBS) for 1 h at room temperature with shaking. Next,membranes wereincubated with appropriate dilutions of primary antibodiesin the blocking buffereitherfor 3-4 h at room temperature or overnight at 4°C with gentle shaking. Post incubation,membranes were washed thrice with 1X TBS-T, 10 min each,with constant agitation. After washes, membraneswere incubated with appropriate dilutions of secondary antibodiesconjugated with horseradish peroxidase (HRP) for 1 h at room temperature with gentle shaking. Next, membranes were washed thrice with 1X TBS-T, 10 min each,with constant agitation. To visualize proteins, membranes were removed from TBS-T, and theHRP substrate ECL plus (Amersham Biosciences, RPN2232) was uniformly added on top of the membrane. Chemiluminescent signalswere captured in the western blot imaging system (FluorChemTME system)
    2. For protein extraction, cells were spun down at 4,000 rpm for 5 min and washed with ice-cold water. The cell pellet was resuspended in 250-500 μl of homogenisation buffer which contained50 mM Tris (pH 7.5), 2 mM EDTA, 1 mM phenylmethylsulphonyl fluoride (PMSF) (serine protease inhibitor), 10 mM sodium fluoride (serine/threonine and acid phosphatases inhibitor), 1 mM sodium orthovanadate (Tyrosine and alakaline phosphatases inhibitor) and 1X protease inhibitor cocktail (Sigma, P 8215). The cell suspensison was transferred to a 1.5 ml centrifuge tube and equal amounts of glass beads (0.5 mm size) were added. Cells were lysed mechanically by bead-beatinghomogenizer (MP Biomedicals, FastPrep®-24) atthemaximum speed for 60 seconds, five times each,with intermittent cooling on ice.After lysis, tubes were punctured at the bottom with the helpofasurgical needle, and the lysed cell suspension was collected in a fresh microcentrifuge tubes by putting the punctured tubes on top of the fresh tubes and centrifuging them at 3,000 rpm for 10 min. The supernatant was transferred toafresh microcentrifugetubeandprotein concentrationwasestimated usingtheBCA protein assay kit (Thermo scientific). Protein preparations werestored at -20°C until use
    1. the selection marker.Knockdown was confirmed by immunoblot analysis with an IP6K1 specific antibody (Table 2.3) as described in Section 2.2.10
    2. lines were used for stable knockdown of IP6K1 expression. Viral particles harboring either non-targeting control or IP6K1directed shRNA were used to infect HeLa or HCT116 cell lines at 0.5 MOI, following treatment with polybrene (8 μg/mL)for 2 h.After 48 h, transduced cells were selected with 2 μg/mL puromycin. Medium was changed twice a week and observed for colony formation. After reaching the optimum growth, selected cells were maintained in DMEM supplemented with 10% FBS and 1 μg/mL puromycin as
    3. HEK293T packaging cellswere seeded at 30-40% confluency in 60 mm dishes. After 24 h, cells were co-transfected with three plasmids required for viral production i.e. VSV-G, psPAX2 (Addgene plasmid # 12260) and pLKO.1-puro-non-targeting and shIP6K1 clones using polyethyleniminereagent(PEI) and incubated at 37°C and 5% CO2 for virion formation. After 48 h, viral particles were harvested by collecting supernatant and filtered througha 0.45 μm syringe filter unit. Viral stock was aliquoted and stored at -80°C for further use. Viral titer was approximated on the number of cells plated for the production of lentivirus. Calculations were done as per Cell Bio Labs instruction. 2 x 106cells will yield 107infectious units/mL. All necessary precautions were taken while generating lentiviral particles such as wearing mask, double gloves, and sterile filter tips. All the consumables used were bleached (1% sodium hypochlorite solution) at least 1 h before being discarded