| Description | Inquire | DescriptionCholesteryl ester transfer protein (CETP) is present in normal human plasma and transfers neutral lipids from high density lipoproteins (HDL) to very low density lipoprotein (VLDL) and low density lipoprotein (LDL). CETP plays an important role in lipoprotein metabolism and influences theDescriptionCholesteryl ester transfer protein (CETP) is present in normal human plasma and transfers neutral lipids from high density lipoproteins (HDL) to very low density lipoprotein (VLDL) and low density lipoprotein (LDL). CETP plays an important role in lipoprotein metabolism and influences the reverse cholesterol transport pathway.Preparation instructionsSuitable for high-throughput screening (HTS), mechanism of action (MOA) studies, and structure-activity relationship (SAR) work in CETP sources.PrincipleThe CETP RP Activity Assay uses a proprietary substrate that enables the detection of CETP-mediated neutral lipid mass transfer. The method is useful for measuring CETP activity in recombinant protein (RP) or purified CETP samples and has a high D... Read More | Inquire | Product introduction： The MA qPCR live bacteria detection kit provides an effective means for detecting bacterial activity. The kit provides a mixture of PMA dye and qPCR based on SYBR Green dye. The optimal amount of dye and the number of samples that can be treated may vary depending on theProduct introduction： The MA qPCR live bacteria detection kit provides an effective means for detecting bacterial activity. The kit provides a mixture of PMA dye and qPCR based on SYBR Green dye. The optimal amount of dye and the number of samples that can be treated may vary depending on the type of sample. PMA is a high-affinity DNA-binding dye, especially with double-stranded DNA. The dye itself has weak fluorescence, but it can emit brighter fluorescence after binding to nucleic acids. PMA is impermeable to cell membranes, so it can selectively modify the DNA of dead cells with damaged membranes. After the PMA-modified DNA is photolyzed by blue light ( ~ 464 nm ), the photoreactive azide group on the PMA is converted into a highly reactive nitrene radical, which reacts with any hydrocarbon near the DNA binding site to form a stable covalent nitrogen-carbon bond, resulting in permanent DNA modification. This modification process will make DNA insoluble and lost with cell debris during the later genomic DNA extraction process. The unbound PMA remaining in the solution reacts with water molecules under strong light irradiation to decompose into hydroxylamine compounds without cross-linking activity, so that it can no longer covalently bind to DNA. Based on this feature of PMA, PMA was combined with qPCR technology to form a new detection method, PMA-qPCR, for the screening of live bacteria. At present, the method has been verified in a variety of bacterial strains, yeast, fungi, viruses and parasites. The treatment of complex samples, such as manure or soil, may require optimization of sample dilution, dye concentration, and light treatment time. The treatment of diluted samples, such as water testing, may require filtration or concentration prior to dye treatment. Matters needing attention：1. please centrifuge the product to the bottom of the tube immediately before use, and then conduct subsequent experiments. 2. the components of the kit contain fluorescent dyes. Avoid light during use and storage. 3. for your safety and health, please wear experimental clothes and disposable gloves.Product parameters:Spectral characteristics :PMA: Ex = 464 nm; Ex/Em = 510/610 nm (following photolysis and reaction with DNA/RNA)Component： PMA：Ex = 464 nm; Ex/Em = 510/610 nm (following photolysis and reaction with DNA/RNA) Instruction： Precautions before use： 1.This live bacteria detection kit distinguishes dead bacteria and live bacteria according to cell membrane permeability. Many methods of killing bacteria cause damage to the cell membrane and are therefore compatible with this kit. But some methods, such as ultraviolet irradiation, may not immediately cause cell membrane rupture. Therefore, before selecting this kit, it is necessary to carry out literature search and pre-experiment to determine whether the kit is suitable for the bacterial type and killing method you choose. 2.After PMA treatment, the bacteria need to be photolyzed to covalently bind the dye to dead cell DNA. Photolysis operations can use blue or white light sources. Generally speaking, the brighter the lamp, the higher the efficiency of the photolysis step. Non-LED lamps ( such as halogen lamps ) may heat your sample and have a negative impact on the analysis. Ice is required to cool the sample during irradiation. 3.Sample can be cryopreservation after photolysis. Frozen samples before PMA treatment photolysis may damage the cell membrane and produce false negative results. If the sample needs to be frozen before detection, it is recommended to perform a pre-experiment first. 4.Part of the mechanism of PMA is to remove PMA covalently modified DNA from the sample by precipitation ; therefore, when extracting genomic DNA, it is necessary to use the same volume of genomic DNA eluent for volume normalization. The positive control can use the genomic DNA of living cells. 5.In order to verify the effectiveness of PMA in the test sample, the Ct ( dCt ) changes between- / + PMA can be compared. Experimental materials ( self-provided )：①Light source ( for the photolysis step after PMA modification of DNA ) ; ② Bacterial genomic DNA extraction kit ; ③ effective qPCR primers corresponding to the sample type Experimental procedure： 1.Suck 10 µL of E.coli bacterial solution in liquid LB medium, and culture E.coli in the bacterial incubator overnight or longer to the logarithmic growth phase ( OD600 ≈ 1.0 ) ; Note : The culture time is adjusted according to the experiment. 2.Two portions of live E.coli, 400 µL each, were placed in a clean centrifuge tube ; 3. ( Recommended ) Preparation of dead E.coli. If the dead E.coli is needed as a control, the dead E.coli can be obtained by heating the living E.coli in a water bath at 95 °C for 5 min, or at 58 °C for 3 h. the subsequent operation of the dead E. coli is the same as that of the living E. coli ; 4.Two copies of live E.coli, one without PMA treatment, and one with 25 µM PMA treatment ( the optimal PMA concentration for treating different types or different sources of bacteria needs to be consulted in the relevant literature ) ; 5.The PMA-treated samples were placed on a shaker at room temperature and incubated in the dark for 10 min to fully mix the dye with the sample ; 6.Exposure of the sample, you can use blue or white light source, irradiation time to explore their own. For example, a 60 W blue light can be used for 15 min. Note : 1 If a halogen lamp is used, we recommend that the PMA-treated sample tube be placed on an ice block 20 cm away from the light source. Ice should be placed in a transparent tray. Adjust the light source to point directly to the sample, photolysis for 5-15 min ; if the bacteria obtained from the environment are directly used for experiments, due to the complexity or turbidity of the environmental samples, the photolysis time needs to be prolonged appropriately. 7.Treated and untreated live E.coli 5000 × g, centrifuged for 10 min, remove the supernatant ; 8.Select the appropriate genomic DNA extraction kit according to the sample type, and use the same elution volume for each group of samples when elution DNA. Note : DNA extraction steps refer to the instructions of the kit used. Part of the mechanism of action of PMA is to remove PMA-bound DNA from the sample by precipitation ; therefore, when extracting genomic DNA, each group should use the same volume of genomic DNA eluent for volume normalization ( the amount of genomic DNA extracted from dead bacteria and live bacteria is inconsistent, so the concentration of the two is significantly different ). 9.Preparation of reaction mixture according to the following system : Note : 1 For the DNA extracted by commercial DNA extraction kit, the qPCR template was optimized with 2 µL as the initial volume ; 2 The template volume should not exceed 10 % of the final reaction volume ; 3 Template concentration : gDNA as template, usually 1-10 ng ; the final concentration of PCR primers is usually 0.4µM, which can get better results. When the reaction performance is poor, the primer concentration can be adjusted in the range of 0.2-1µM. 10.Slightly vortex the reaction mixture, transfer the fixed volume to the PCR tube. 11. Test procedure Note : 1 The extension time is adjusted according to the instrument ; the Taq enzyme in mix can be activated within 2 min, but the genomic DNA may require longer denaturation time, which can be increased at this time, and the specific denaturation time can be adjusted according to the sample type.12. ( Optional ) Data analysis Using live bacteria and dead bacteria as controls, the number of live cells in the sample was analyzed and calculated. It is recommended to verify the suitability of primers and PCR procedures before starting PMA qPCR detection of live bacteria. Calculation of dead and living bacteria control dCt ( 1 ) After the end of qPCR, the Ct value of each sample was calculated by instrument software ; ( 2 ) By calculating the dCt of each control bacteria, it was judged whether PMA successfully inhibited the amplification of dead bacterial DNA. The calculation is as follows : dCt live = Ct ( live, PMA treated ) -Ct ( live, PMA untreated ) dCt die = Ct ( die, PMA treated ) -Ct ( die, PMA untreated ) ( 3 ) The dCt expectation of living bacteria is close to 0 ± 1, which indicates that PMA does not affect the amplification of living cell DNA ;( 4 ) The expected value of dCt of dead bacteria is greater than 4 ( dCt is 4 means that it is reduced by about 16 times, that is, 94 % of dead bacterial DNA is removed ; a dCt of 8 indicated a decrease of about 250 times, that is, 99.6 % of the dead bacterial DNA was removed ).( 5 ) The dCt of dead bacteria depends on many factors, including : strain / cell type ; the way bacteria are killed ; the concentration of PMA used ; amplified sequence length. 13. Calculation of the proportion of viable ( optional ) bacteria If the control results of dead and live bacteria are normal, the proportion of live bacteria in the sample can be calculated.( 1 ) Calculate the dCt value of the sample : dCt sample = Ct ( sample, PMA treated ) -Ct ( sample, PMA untreated ) ( 2 ) Conversion of dCt value to live bacteria ratio : PMA inhibition multiple = 2 ( sample dCt ) Viable bacteria % = 100 / PMA inhibition multiple 14. ( Optional ) Calculate the absolute number of live bacteria If you want to calculate the absolute number of viable bacteria in the sample, you need to use a known number of target bacteria genomic DNA to make a standard curve. It is recommended that the diluted concentrations of several groups of genomes are within the range of the qPCR analysis system.( 1 ) qPCR was performed with the appropriate genome, and the Ct value was used as the ordinate, and the number of cells was used as the abscissa. The R2 value is calculated to determine the linearity, and the slope and y-axis intercept are displayed. ( 2 ) Calculate the copy number of the experimental samples : Ct = slope * cell number + y axis intercept ( y = mx + b ) Bacterial count sample = ( Ct-y axis intercept ) / slope Note : The live bacterial DNA was not lost during the purification process. Examples : Scope of application：Live bacteria detection... Read More | Products R669890Component50 TStorageR669890ADNase I1000 U-20℃. Avoid freeze/thaw cycle.R669890B10×Reaction Buffer1mL-20℃. Avoid freeze/thaw cycle.R669890CBuffer RL35 mLRTR669890DBuffer RW140 mLRTR669890EBuffer RW2 (concentrate)11 mLRTR669890FRNase-Free Water10 mLRTR669890GSpin Products R669890Component50 TStorageR669890ADNase I1000 U-20℃. Avoid freeze/thaw cycle.R669890B10×Reaction Buffer1mL-20℃. Avoid freeze/thaw cycle.R669890CBuffer RL35 mLRTR669890DBuffer RW140 mLRTR669890EBuffer RW2 (concentrate)11 mLRTR669890FRNase-Free Water10 mLRTR669890GSpin Columns FL with Collection Tubes50 setsRTR669890HSpin Columns RM with Collection Tubes50 setsRTR669890IRNase-Free Centrifuge Tubes (1.5 mL)100 EART ProductsThis kit adopts centrifugal adsorption columns with high efficiency and specificbinding of nucleic acids and unique buffer system, which can rapidly extract totalRNA from bacteria or cultured animal cells.The reaction can be completed in 30-40minutes, and the extracted total RNA is extremely pure and free of protein and othercontaminants, which is suitable for RT-PCR, Real-Time RT-PCR, microarray analysis,in vitro translation and other experiments. Self-contained reagents: Lysozyme, β-mercaptoethanol, anhydrous ethanol (freshlyopened or for RNA extraction). Pre-experiment Preparation and Important Notes 1. To prevent RNase contamination, attention should be paid to the following aspects:1) Use RNase-free plastics and tips to avoid cross-contamination. 2) RNase-free water should be used to prepare the solution. 3) Operators wear disposable masks and gloves, and change gloves diligently duringthe experiment. 2. Add β-mercaptoethanol to Buffer RL before use to reach a final concentrationof 1%, e.g., add 10 µl of β-mercaptoethanol to 1 ml of Buffer RL. Buffer RL withβ-mercaptoethanol can be stored at 4℃ for 1 month, if precipitation occurs, pleaseheat to dissolve and use.3. Anhydrous ethanol should be added to Buffer RW2 before first use according tothe instructions on the reagent bottle label. 4. All centrifugation steps are carried out at room temperature if not otherwisespecified, and all steps should be performed quickly. Procedure 1. Centrifuge at 12,000 rpm (~13,400 x g) at 4°C for 2 minutes to collect theorganisms (maximum volume of organisms should not exceed 1 x 109) and carefullyremove all supernatants. Note: Supernatants that leave residues can interfere with the subsequent digestionprocess. 2. Thoroughly resuspend the organisms with 100 µl of TE buffer containing Lysozymeand incubate at room temperature. The specific formulation and incubation time areas follows:/The final concentration of Lysozyme in TE bufferincubation timeG-germ400µg/ml3-5minG+germ3mg/ml5-10min 3. Add 350 µl of Buffer RL (check that β-mercaptoethanol has been added beforeuse), vortex and shake to mix (insoluble precipitate may appear in this step), addall of the solution and the precipitate to the filter columns (Spin Columns FL) thathave been loaded into the collection tubes, and centrifuge at 12,000 rpm for 2minutes. 4. Add 250 µl of anhydrous ethanol to the filtrate obtained in the previous stepand mix well (a precipitate may appear at this point). Transfer the resulting solution together with the precipitate to a Spin Columns RM packed in a collectiontube, centrifuge at 12,000 rpm for 1 min, discard the waste solution and put thecolumn back into the collection tube.5. Add 350 µl Buffer RW1 to the adsorbent column, centrifuge at 12,000 rpm for1min, discard the waste liquid and put the adsorbent column back into the collectiontube.6. Preparation of DNase I mixture: Take 52µl of RNase-Free Water, add 8µl of 10×Reaction Buffer and 20µl of DNase I (1U/µl) to it, mix well, and make a finalvolume of 80µl of reaction solution.7. Add 80µl of DNase I mixture directly to the adsorption column and incubate at20-30°C for 15 minutes.8. Add 350 µl Buffer RW1 to the adsorbent column, centrifuge at 12,000 rpm for1min, discard the waste liquid and put the adsorbent column back into the collectiontube.9. Add 500 µl of Buffer RW2 to the column (check that anhydrous ethanol is addedbefore use), centrifuge at 12,000 rpm for 1 min, and discard the waste solution.10. Repeat step 9.11. Place the adsorbent column back into the collection tube and centrifuge at 12,000rpm for 2 minutes. Note: The purpose of this step is to remove residual ethanol from the adsorptioncolumn; ethanol residue can interfere with subsequent enzymatic reactions (zymography, PCR, etc.).12. Load the adsorption column into a new RNase-Free collection tube, add 30-50 µl of RNase-Free Water to the middle of the adsorption membrane, leave it at roomtemperature for 1 minute, centrifuge at 12,000 rpm for 1 minute, collect the RNAsolution, and store the RNA at -70°C to prevent degradation. Note: 1) The volume of RNase-Free Water should not be less than 30 µl, too smallvolume affects the recovery rate. 2) If you want to increase the RNA yield, repeat step 12 with 30-50 µl of freshRNase-Free Water. If the RNA concentration is to be increased, the resulting solution can be reintroduced into the adsorption column and step 12 repeated... Read More |