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  1. Jul 2019
  2. Jun 2019
    1. Purified HbS was digested with carboxypeptidase B (200 mg hemoglobin to 1 mg of the enzyme) for 3 hours in freshly prepared 0.05 M Tris-acetate buffer pH 7.1) at 25°C , followed by passage through a cation-exchange column using Whatman CM52.
    2. Preparation of HbS{des arg 141a
  3. May 2019
    1. After PCR, 1 μl of Dpn1 enzyme (10U/μl) was added to the amplification mix and incubated at 37°C for 6hours. After that, 10ml of the amplification mix was taken to transform Dh5a cells. Positive clones were selected after confirming the sequence of plasmid DNA
    2. The PCR parameters were as follows
    3. The reaction mix included 2ml of PSKll(39+) (50ng) containing wild type K-Ras cDNA , 5ml 10x buffer, 20pmoles of primers , 1ml of 10mM dNTP mix and 1ml of deep vent polymerase (NEB).
    4. The following K-Ras-ras mutants were generated by site directed mutagenesis according to the protocol described in QuickChange site directed mutagenesis kit (Stratagene). The primers used are shown in the following table
    5. Site Directed Mutagenesis
    1. Denaturation 95°C 1 min After 30 cycles of PCR, the final elongation step was carried out again for 10 min at 72°C
    2. The PCRs were normally performed using a PCR amplification kit from Fermentas/Sigma (USA), following the company's protocols. Approximately, 10 ng of chromosomal or 1-2 ng of plasmid DNA was used as template in a 50 μl reaction volume containing 0.2 mMM of each dNTP, 20 picomoles each of forward and reverse primer and 0.5 units of Taq DNA polymerase. In some cases, freshly streaked E.coli cells from a plate were resuspended in 50 μl of sterile Milli Q water to get a cell suspension (~ 109 cells/ml) and 10 μl from this was used as the source of DNA template. The samples were subjected to 30 cycles of amplification and the typical conditions of PCR were as follows (although there were slight modifications from one set of template/primers to another): The initial denaturation was done at 95°C for 3 min and the cycle conditions were as given below. Annealing 55°C 1 min Elongation 72°C (1 min/kb of DNA template to be amplified)
    3. Polymerase chain reaction (PCR)
    1. were maintained in log-phase by continuous passaging in fresh YNB medium every 4 h
    2. 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
    3. Phosphate starvationof yeast cells
    4. .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

      E.

    5. E.coliBW23473transformation by electroporationE
    6. 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
    7. Yeast transformation usinglithium acetate (LiOAc) strategy
    1. 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
    2. Micrococcal nuclease digestion assay
    3. 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
    4. 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
    5. Harvesting of and treatment to logarithmic phase C. glabratacells
    6. 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
    7. Harvesting of macrophage-internalized C. glabratacellsfor RNA and protein extraction
    1. nvolved use of GFP based vector system, the expression of the transgene was visualized under fluorescent microscope with excitation filter of 485+20 nm
    2. Transient transfection of plasmid DNA in cellswas performed usingLipofectamine 2000transfection reagentaccording to manufacturer’s protocol. Briefly, 0.5 to 1million cellswere seeded in a 35mm tissue culture dish one day prior totransfection. For each 35mm dish, 4μg DNA was mixed in 250μl of Opti-MEMin one polypropylene tube. In another tube 10μl of Lipofectamine 2000 was diluted in250μl Opti-MEM and incubated at room temperature for 5 minutes. DNA and Lipofectamine 2000 were mixed together and allowed to form complexes for 30minutes at room temperature. Meanwhile, the adherent cells were washed twicewithPBS and 1ml of Opti-MEM was added. 500μl of complexes were then added to each dishcontaining cells and medium. After 6-8 hrs, the medium containing complexes wasremoved and complete medium was added and transgene expression was evaluated 24-48 hrs after transfection. Since most of the experiments
    3. Transient transfection in adherent cells
    1. Co-Immunoprecipitation assays were performed essentially as described by Lee (Lee, 2007). For a typical immunoprecipitation assay, cells were washed with ice-cold PBS and scapped in ice-cold microfuge tube. Then, cells were lysed with NETN buffer (containing 1 μg/ml each of leupeptin, aprotinin, 10mMeach ofNaF and phenylmethylsulfonyl fluoride (PMSF))on shaking rotator in cold room for 30 min. After centrifugation, the whole cell lysate (500 μg-1 mg) obtained was incubated with 1 μg of antibody of interest(orwithisotype control)on shaking rotator in cold room for 3 h, followed by addition of 10-20 μl of ProteinSepharose A/G beads (Santa Cruz) for 1 h. The immuno-complexes bound to beads were then pelleted atlow speed centrifugation (2500 rpm for 3 min) and washed three times with NETN buffer. The proteins bound to beadswere resolved by SDS-PAGE and immunoblotting was performed accordingto standard protocol described earlie

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    2. Co-Immunoprecipitation (Co-IP)
    1. After the HPLC run, vials numbered from 50 to 65 were surveyed using a Geiger counter, 4 vials with high counts were pooled into one vial and 5 μL of this 4 mL solution was measured in a liquid scintillation counter (Perkin Elmer). To the remaining solution, 800 μL of 50% ammonia solution was added to neutralise the pH and the tube was kept on ice. In a 50 mL conical tube, 45 mL of chilled water was taken, to which the neutralised IP7solution was added and kept on ice. A Sep-Pak cartridge [Waters, WAT020545] was equlibrated with 10 mL of ice cold deionized water using a 10 mL syringe. The Sep-Pak cartridge was attached to a 60 mL syringe and 50 mL of diluted IP7 solution was passed slowly through ot so that IP7would bind to the Sep-Pak column. The cartridge was washed with 8 mL of chilled water, followed by chilled 8 mL 0.2 M triethylammonium bicarbonate solution pH 8.5 (4 mL of 1.5 M triethylammonium bicarbonate, pH 8.5 + 26 mL chilled water). The bound IP7 was eluted in 4 mL of 1.5 M triethylammonium bicarbonate solution, pH 8.5, into three 1.5 mL microfuge tubes. The eluted IP7 was concentrated in a vacuum concentrator (Scanvac) at 2000 rpm, 25°C, to obtain 30-50 μL of a 1-2 μCi/μL solution of radiolabelled IP7
    2. A mixture of 40 mL of DEPC treated water and 0.6 gof agarose was meltedby boiling. After cooling down the temperature to 55°C, 8.4 mL of formaldehyde (final concentration 2.2 M)and 5 mL of 10X MOPS were added, mixed well and poured into a boat to cast a gel
    3. Preparation of formaldehyde agarose gel(50 mL) and RNA sample
    1. protein agarose beads for 1 hour at 4 c and then washed three times with 1X NETN. The proteins bound to S-protein agarose beads were resolved by SDS-PAGE and visualized by Coomassie staining. Proteinspresent in the gels were analyzed by Mass Spectroscopy
    2. HEK293T cells were transfected with S-protein/FLAG/SBP (streptavidin binding protein)-triple tagged WWP2/Dvl2 and then three weeks later puromycin-resistant colonies were selected and screened for WWP2/Dvl2 expression. The positive stable cells were then maintained in RPMI1640 supplemented with 10% FBS and 2 g/ml puromycin. The stable cells(harvested cells from ~30 tissue culture plates of 10cm size)were collected in 1X PBS by scraping them off the plates, and were lysedwith NETN buffer (20 mM Tris-HCl,pH 8.0, 100 mM NaCl, 1 mM EDTA, 0.5 % Nonidet P-40) containing 50 mM -Glycerophosphate, 10 mm NaF, 0.5 mM PMSF, 1 g/ml of each Pepstatin and Aprotinin on ice for 20 minutes. After removal of cell debris by spinning, cell lysates were incubated with streptavidin sepharose beads for 1 hour at 4C. The bound proteins were washed three times with 1X NETN and then eluted twice with 2 mg/ml Biotin for 60 minutes at 4 C. The eluateswere incubated with S-
    3. Tandem affinity purification
    1. culture dishes and dishes were incubated at 28ºC. OD600 was measured after 16 and 42 h of incubation, and percentage inhibition of growth was determined with respect to the growth in the corresponding control cultures containing PS media without streptonigrin
    2. For streptonigrin sensitivity assay, different strains of Xanthomonas oryzaepv. oryzicolawere grown overnight with appropriate antibiotics as described earlier. 0.2% of primary inoculum was added into fresh PS medium and grown for 24 h till the OD600reached 0.6. Serial dilution of bacterial cultures were performed as mentioned earlier, and 5μl diluted cultures were spotted on PSA plates containing different concentration of streptonigrin (0.05 μg/ml, 0.1 μg/ml and 0.15 μg/ml). Plates were incubated at 28ºC for 72 h and plate images were captured and analyzed for comparative growth inhibitionin different strains caused by streptonigrin. Further, streptonigrin sensitivity assay in liquid broth was performed by growing different strains as described previously (Wilson et al., 1998).Briefly, Xanthomonas oryzae pv. oryzicolastrains were grown to an OD of 1 in PS medium with appropriate antibiotics. Cells were pelleted down, and resuspended in fresh PS medium at an OD600of 0.6. Next, 100 μl culture was inoculated in 4 ml PS medium with or without streptonigrin. Streptonigrin was added to a final concentration of 0.1μg/ml into
    3. Streptonigrin sensitivtity assay
    4. insert of 1:3 for sticky end ligations. Ligation mix was incubated either at 22°C for 30 min or 16°C for 14-16 h. After incubation, T4DNA ligase was inactivated at 65°C for 20 min
    5. After restriction enzyme digestion, digested products were resolved on agarose gels, and desired DNA fragments were extracted from the gel. Otherwise digested DNA fragments were precipitated by Phenol-choloroform-isoamyl alcohol method. Concentration of gel extracted or precipitated fragments were determined using spectrophotometer and ligation reactions were set up using a molar ratio
    6. Ligation
    1. For Yeast colony PCR, yeast cells were subjected to zymolyase (MP Biomedicals, 0832092) digestion to obtain thespheroplast. To perform zymolyase digestion, a digestion cocktail was prepared in 1XPBS consisting of zymolyase (2.5mg/ml) and sorbitol (1.2 M). The cocktail was dispensed in 0.2ml PCR tubes in 10 μl aliquots anda tip-full of yeast cells wasadded to these tubes. Tubes were incubated at 37°C for 2-3 h and 1 μl of digested mixture was used as a template in a PCR reaction
    2. Yeast colony PCR
    3. For Yeast colony PCR, yeast cells were subjected to zymolyase (MP Biomedicals, 0832092) digestion to obtain thespheroplast. To perform zymolyase digestion, a digestion cocktail was prepared in 1XPBS consisting of zymolyase (2.5mg/ml) and sorbitol (1.2 M). The cocktail was dispensed in 0.2ml PCR tubes in 10 μl aliquots anda tip-full of yeast cells wasadded to these tubes. Tubes were incubated at 37°C for 2-3 h and 1 μl of digested mixture was used as a template in a PCR reaction
    4. Yeast colony PCR
    1. dropped on clean prechilled slides held at a 45°angle from a height of 18 inches, dried at 55°Con a hot plate and stained with 3% geimsa in phosphate buffer (pH 6.8) for 10 min. Slides were washed three times and dried, individual metaphase spreads were analyzed using bright field microscopy (Zeiss Axio Scope), and chromosomal aberrations were scored manually from each spread
    2. MEFsplated in 6 cmdishes were treated with MMC (300 nM) for 12 h. Post damage cells were treated with colcemid (0.1 μg/mL) for 4 hto arrest cells in metaphase. After 4 h cells were washed twice with PBS to remove traces of colcemid and harvested by trypsinisation, pelleted down at 100 x g for 5 min in 15 mL conical tubes. The supernatant was removed by leaving 0.5 mL and resuspended thoroughlyby pippeting. Cells were subjected to hypotonic swelling in pre-warmed 0.075 M KCl for 15 min at 37°C[Note: key to this step is to add hypotonic solution drop by drop slowly otherwise cell clumps will form which are impossible to disperse. Add a few drops first then pipette the cells up and down to mix them thoroughly and add few more drops. Invert tubes 2-3 times during the incubation]. After 15 min cells were fixed by adding few drops of chilled fresh fixative (methanol: glacial acetic acid; 3:1) kept in the deep freezer. Cells were pelleted down at 100 x g for 8 min, the supernatant was removed, 0.5 mL of fixative was left behind and the pellet was resuspended very gently. Slowly fresh fixative was added in the same manner as the KCl solution and cells were pelleted down at 100 x g for 8 min; this step was repeated twice. The supernatant was removed by leaving 0.5 mL fixative and the cells were resuspended and mixed well before preparing metaphase spreads. Cell suspensions were
    3. Cytogenetic analysis