| Description | Q665720 Component 200T Storage Q665720A Buffer L2 25 mL RT Q665720B Buffer N3 80 mL RT Q665720C Buffer PB 35 mL RT Q665720D Buffer PW (concentrate) 25 mL RT Q665720E Buffer EB 30 mL RT Q665720F RNase A (10 mg/mL) 800 渭L RT Q665720G Spin Columns DM with Collection Tubes 200 EA RTProduct Q665720 Component 200T Storage Q665720A Buffer L2 25 mL RT Q665720B Buffer N3 80 mL RT Q665720C Buffer PB 35 mL RT Q665720D Buffer PW (concentrate) 25 mL RT Q665720E Buffer EB 30 mL RT Q665720F RNase A (10 mg/mL) 800 渭L RT Q665720G Spin Columns DM with Collection Tubes 200 EA RTProduct IntroductionThe biggest feature of this kit: simple and fast, high extraction volume. The whole extraction process does not take more than 10 minutes, without centrifugation to collect bacteria and resuspend the bacterium, directly add the unique super lysate Buffer L2 to the cultured bacterial solution, followed by neutralization, centrifugation and passing through the column, and the extracted plasmid can be as high as 30 µg, and maximize the removal of proteins, genomes and other impurities. The extracted plasmid DNA can be directly used for bacterial transformation, digestion, PCR, in vitro transcription, sequencing and other downstream experiments.Self-contained reagent: anhydrous ethanol.Pre-experiment Preparation and Important Notes1. The kit can be stored in a dry, room temperature (15-30°C) environment for 1 year. For longer storage, the centrifuge columns can be placed at 2-8°C.2. Before the first use, add all of the RNase A solution to Buffer N3, mix well, and store at 2-8°C.3. Anhydrous ethanol should be added to Buffer PW before the first use according to the instructions on the reagent bottle label.4. If there is any precipitation in Buffer L2 before use, please put it in a 37℃ water bath and keep mixing until the solution becomes clear before use.Operation steps1. Take 600 µl of bacterial culture into a 1.5 ml centrifuge tube (supplied).2. Add 100 µl of Buffer L2 to the above centrifuge tube and gently turn the solution up and down 8 times; the solution should change from turbid to a clear purple color, indicating complete lysis. The cleavage time should not exceed 2 minutes.3. Add 350 µl of Buffer N3 to the above centrifuge tube (please check that RNaseA has been added first) and immediately mix well by turning up and down about 8-10 times, at which point the solution should turn completely yellow and a yellow precipitate should form. centrifuge at 13,000 rpm for 2-3 minutes.4. Slowly pour the supernatant obtained in step 3 into the prepared adsorption columns (Spin Columns DM with Collection Tubes) to avoid sedimentation into the columns.5. Centrifuge at 13,000 rpm for 15 seconds, pour off the waste liquid in the collection tube, and put the adsorption column back into the collection tube.6. Add 150 µl Buffer PB to the adsorption column and centrifuge at 13,000 rpm for 15 seconds.7. Add 400 µl Buffer PW to the adsorption column (please check that anhydrous ethanol has been added first) and centrifuge at 13,000 rpm for 1 minute.8. Place the adsorbent column in a new centrifuge tube (self-provided), add 30-100 µl Buffer EB to the middle part of the adsorbent membrane, centrifuge at 13,000 rpm for 1 min, collect the plasmid DNA, and store at -20°C for long term storage.When the amount of extracted bacterial liquid is >600µl, the following procedure can be used:1. This kit can extract up to 3ml of bacterial solution, if the amount of extracted bacterial solution is more than 600µl, it is necessary to centrifuge the bacterial solution exceeding 600µl at 13,000rpm for 30 seconds (to collect the bacterial body), discard the supernatant and then add 600µl of bacterial solution, and then resuspend the bacterial body at the bottom of the tube thoroughly and then proceed to the following operation.2. Add 100µl Buffer L2 to the above centrifuge tube, gently invert the solution up and down 10 times, if the solution is not clarified, need to continue to invert the mixing until the solution becomes a clear purple color, the lysis time should not be more than 2 minutes. (If the solution is still turbid, the amount of bacteria is too large, and the amount of bacteria should be reduced appropriately.)3. Add 350 µl of Buffer N3 to the above centrifuge tube (please check that RNaseA has been added first) and immediately mix well by turning up and down until the purple solution turns completely yellow and a yellow precipitate is formed before proceeding to the next step. centrifuge at 13,000 rpm for 5 minutes.4. Transfer the supernatant to a new centrifuge tube, add 200 µl of isopropanol, mix up and down several times, mix well and transfer to the adsorbent column (Spin Columns DM with Collection Tubes), due to the amount of solution is too large, this time, it is necessary to centrifuge the column in two separate times, centrifugation at 13,000 rpm for 15 seconds, pour off the waste liquid in the collection tube, and put the adsorbent column back to the The adsorbent column should be placed back into the collection tube.5. Add 150 µl Buffer PB to the adsorption column and centrifuge at 13,000 rpm for 15 seconds.6. Add 400 µl Buffer PW to the adsorption column (please check that anhydrous ethanol has been added first) and centrifuge at 13,000 rpm for 1 minute.7. Place the adsorbent column in a new centrifuge tube (self-provided), add 50-200 µl Buffer EB to the middle part of the adsorbent membrane, leave it at room temperature for 2 min, centrifuge at 13,000 rpm for 1 min, collect the plasmid DNA, and store it at -20°C for a long time... Read More | Product contentG665801Component100 TStorageG665801A2×GoldStar Probe One Step Buffer1.4 mL-20℃. Avoid freeze/ Thaw cycle. Protect from light.G665801BGoldStar Probe One Step EnzymeMix100 µL-20℃. Avoid freeze/ Thaw cycle. Protect from light.G665801C50×High ROX50 µL-20&#Product contentG665801Component100 TStorageG665801A2×GoldStar Probe One Step Buffer1.4 mL-20℃. Avoid freeze/ Thaw cycle. Protect from light.G665801BGoldStar Probe One Step EnzymeMix100 µL-20℃. Avoid freeze/ Thaw cycle. Protect from light.G665801C50×High ROX50 µL-20℃. Avoid freeze/ Thaw cycle. Protect from light.G665801DRNase-Free Water1.5 mL-20℃. Avoid freeze/ Thaw cycle. Product Introduction This product is a specialized kit for one-step Real-Time RT-qPCR using the probe method (TaqMan, Molecular Beacon, etc.). When using this product for Real Time RT-qPCR reaction, reverse transcription and quantitative PCR are carried out in the same reaction system, and there is no need to add reagents or open the cap of the tube during the reaction process, which avoids contamination and improves the experimental efficiency at the same time. With high detection sensitivity, strong fluorescence signal and high signal-to-noise ratio, this product is very suitable for the detection of RNA viruses and other trace RNA. The special buffer system contained in this product can maximize the effectiveness of reverse transcriptase and DNA polymerase at the same time and improve the efficiency of the reaction. A wider linear range can be obtained with this product, more accurate quantification of the target gene, good reproducibility and high confidence.ROX dye is used to correct the fluorescence signal error generated between wells of a quantitative PCR instrument, and is generally used in Real Time PCR amplifiers from ABI, Stratagene, and other companies. The excitation optics vary from instrument to instrument, so the concentration of ROX dye must be matched to the corresponding fluorescence quantitative PCR instrument. Instruments that do not require ROX calibration (G665836) Roche LightCycler 480, Roche LightCyler 96, Bio-rad iCyler iQ, iQ5, CFX96 and others. Instruments that require High ROX calibration (G665801) ABI Prism 7000/7300/7700/7900, Eppendorf, ABI Step One/Step One Plus, and others.matters needing attention1.Before using the reagents in this kit, please mix them gently by turning them up and down to avoid foaming as much as possible, and use them after brief centrifugation.2.This product uses RNA as the template for one-step RT-PCR experiment, RNase contamination should be avoided during operation, it is recommended to operate RNA in a special area, use special instruments and consumables, the operator with a mask and disposable gloves and often change the gloves, the experiment-related consumables should be processed with 0.1% DEPC (diethyl ether pyrocarbonate) aqueous solution for 12 hours at 37℃, and autoclaved for 30 minutes before use. The consumables should be treated with 0.1% DEPC (diethylpyrocarbonate) aqueous solution at 37℃ for 12 hours and autoclaved for 30 minutes.3.Repeated freezing and thawing of each reagent in this kit should be avoided as much as possible; repeated freezing and thawing may degrade the product performance.4.This kit must use specific primers, the choice of primers can be selected according to specific experiments, the good or bad primer design directly affects the results of RT-qPCR reaction, the design of primers need to consider the GC content, primer length, primer position, the secondary structure of the PCR product and other factors, it is recommended to use a professional primer design software for design.5.This kit is recommended to use specific probes, and it is recommended to use professional design software for designing.UsageThe following examples are conventional reaction systems and conditions, which should be improved and optimized according to the different templates, primer structures and target fragment sizes in actual operation. (Please prepare the reaction solution on ice.)1. Dissolve RNA template, primers, 2× GoldStar Probe One Step Buffer, GoldStar Probe One Step EnzymeMix and RNase-Free Water and set aside on ice.2. PCR reaction system:reagents25µl reaction systemfinal concentration2×GoldStar Probe One Step Buffer12.5µl1×Forward Primer, 10µM0.5µl0.2µM¹⁾Reverse Primer, 10µM0.5µl0.2µM¹⁾Probe, 10µM0.5µl0.2µM²⁾GoldStar Probe One Step EnzymeMix1.0µl RNA TemplateXµl10pg-100ng³⁾50 x Low ROX or High ROX (optional)⁴⁾0.5µl1×RNase-Free WaterUp to 25µlNote: 1) Usually, better results can be obtained with a primer concentration of 0.2 µM, and 0.1-1.0 µM can be used as a reference for setting the range.(2) The concentration of the probe used is related to the fluorescence quantitative PCR instrument used, the type of probe, and the type of fluorescent labeling substance, please refer to the instrument manual or the specific requirements for the use of each fluorescent probe for the adjustment of the concentration in actual use.(3) Usually the amount of RNA template is 10pg-100ng as a reference. Since the templates of different species contain different copy numbers of target genes, the templates can be diluted in gradient to determine the optimal amount of template to use.(4) The excitation optical system varies from instrument to instrument, choose to add 50×Low ROX or 50×High ROX according to the instrument using fluorescence quantification.3. Mix well, centrifuge briefly, and collect the solution at the bottom of the tube.4.RT-PCR reaction conditions:Note: 1) The hot start enzyme used in this product must be activated under the condition of pre-denaturation 95℃, 5-10min. 2) It is recommended to use the two-step PCR reaction program, if you can not get good experimental results due to the use of primers with lower Tm value, etc., you can try to carry out the three-step PCR amplification, and the annealing temperature should be set in the range of 56℃-64℃ as a reference... Read More | Inquire | Products content Products IntroductionThis kit is a dedicated sample preparation solution for microbiome analysis and is suitable for the purification and enrichment of genomic DNA of pathogenic microorganisms such as bacteria and fungi from mixed samples such as swabs, blood, sputum, alveolar Products content Products IntroductionThis kit is a dedicated sample preparation solution for microbiome analysis and is suitable for the purification and enrichment of genomic DNA of pathogenic microorganisms such as bacteria and fungi from mixed samples such as swabs, blood, sputum, alveolar lavage, etc. During the purification process, differential lysis of the host cells and subsequent enzymatic digestion can effectively remove most of the host DNA while providing a comprehensive coverage of the bacterial and fungal DNA loci to a higher level. By differential lysis of host cells and subsequent enzymatic digestion, this kit can effectively remove most of the host DNA while maximizing the full coverage of bacterial, fungal and other pathogenic microbial DNA sites, thus obtaining microbiome DNA enrichment products with a higher coverage. Microbial DNA purified with this kit is suitable for a variety of downstream applications, including whole genome sequencing analysis, 16S rDNA-based high sensitivity microbiome analysis, and macrogenomic birdshot sequencing analysis. Self-contained reagents and consumablesSterile pipette tips with aerosol barrier to prevent cross-contamination anhydrous ethanol Microcentrifuge tubes (2 ml/1.5 ml) PBS buffer (required for some samples only)Pre-experiment Preparation and Important Notes1. Add 1.25 ml Proteinase K Storage Buffer to Proteinase K and store at -20℃. Do not leave the prepared Proteinase K (20 mg/ml) at room temperature for a long time, and avoid repeated freezing and thawing to avoid affecting its activity.2. Dissolve Lysozyme (100 mg) in 10 ml Enzymatic Lysis Buffer to a final concentration of 10 mg/ml, dispense into sterile tubes and store at -20℃. Do not leave the prepared Lysozyme (10 mg/ml) at room temperature for a long time and avoid repeated freezing and thawing to avoid affecting its activity.3. Thaw Buffer GB1 and Buffer GB2 at room temperature or 2-8°C before use and mix thoroughly. Thawed Buffer GB1 and Buffer GB2 can be left at 2-8°C for 1-2 weeks without affecting their activity, and should be stored at -20°C for long term storage. To ensure optimal performance, do not freeze or thaw more than three times. If less than one bottle of Buffer GB1 and Buffer GB2 is required for a single extraction, ensure that it is used under sterile conditions such as an ultra-clean bench and avoid microbial contamination and growth in the remaining buffer.4. Before first use, anhydrous ethanol should be added to Buffer GW1 and Buffer GW2 according to the instructions on the vial label and labeled.5. Check Buffer GL for crystallization or precipitation before use, and if crystallization or precipitation occurs, redissolve Buffer GL in a 56°C water bath.6. If the downstream experiments are sensitive to RNA contamination, 4 µl of DNase-Free RNase A (100 mg/ml) can be added before adding Buffer GL. RNase A is not provided in the kit, but can be ordered separately from CW0601S.7. This kit is designed for the isolation of DNA from intact microbial cells. To ensure optimal recovery of microbial DNA, samples should be fresh. If storage or transportation is required, this should preferably be done at 2-8°C and not frozen or thawed, as freezing and thawing can damage the integrity of the microbial cells and therefore result in the loss of exposed microbial DNA during host DNA removal.8. To avoid false results due to contamination, keep the work area clean, wear protective clothing, and set up controls for quality control. Use appropriate measures to handle sample materials to minimize the risk of cross-contamination. During the extraction process, use DNA-free pipette tips and consumables, and cap reagents immediately after use to prevent contamination. procedure1. Sample pre-treatment: 1a: For swab samples, swirl the swab portion of the swab in 0.5 ml PBS for at least 20 s. Squeeze the swab several times against the wall of the tube before removing it so that as much of the bacterial fluid as possible can be squeezed out of the swab to minimize sample loss. 1b: For viscous samples, e.g. sputum, take ~500 µl of sample, add 1.5 times the volume (~750 µl) of Buffer GB1 and incubate at 37°C, 600 rpm for 15-30 min until the sample is completely liquefied.Note: The sample volume can be increased or decreased appropriately and the amount of Buffer GB1 added adjusted accordingly.1c: For alveolar lavage fluid containing a small amount of viscous sputum, centrifuge as much of the alveolar lavage fluid as possible, carefully remove the supernatant, and retain the lower viscous fraction (containing sputum, cells, and organisms), add 1.5 times the volume of Buffer GB1, and incubate for 15-30 min at 37°C, 600 rpm until the sample is completely liquefied.1d: For non-viscous body fluid samples such as blood and cerebrospinal fluid, liquefaction treatment is not required, and an appropriate amount of sample is taken directly, the operation of step 2 is carried out, and the cell precipitate is collected by centrifugation.2. Centrifuge at 10000 rpm for 5-10 min at room temperature and carefully discard the supernatant.Note: Do not disturb the lower cell sediment to avoid sample loss.3. Add 500 µl Buffer GB2, vortex to mix, and incubate at room temperature, 600 rpm for 10 min. 4. Centrifuge at 12000 rpm for 2 min and carefully remove the supernatant.Note: Do not disturb the bacterial precipitate when removing the supernatant to avoid sample loss.5. Add 200 µl of Buffer GB2 to the precipitate, add 2 µl of Benzonase and incubate for 30 min at 37°C, 600 rpm. 6. Centrifuge at 12000 rpm for 2 min, discard the supernatant, add 500 µl of Buffer GB2, vortex and wash the precipitate. Repeat the procedure once.7. Centrifuge at 12000 rpm for 2 min, discard the supernatant, and finally aspirate the residual Buffer GB2 with a small-volume tip. 8. Add 180 µl Lysozyme (10 mg/ml), resuspend the bacterial precipitate and transfer the bacterial resuspension to a Lysis Tube.9. The Lysis Tube is incubated at 37°C, 600 rpm for 20-30 min, then vortexed for 10 min or processed on a thermostatic homogenizer for 10 min at maximum vibration speed (2500-2900 rpm).10. Centrifuge briefly, add 20 µl proteinase K, vortex to mix, add 200 µl buffer GL, vortex to mix, and incubate for 30 min at 56°C, 600 rpm. Note: 1) Do not add Proteinase K directly to Buffer GL.2）For RNA removal, add 4 µl DNase-Free RNase A (100 mg/ml) before adding Buffer GL, shake to mix, and let stand at room temperature for 5-10 minutes.11. Centrifuge at 12000 rpm for 1 min and carefully aspirate the supernatant into a new centrifuge tube. Note: Do not aspirate the glass beads.12. Add 200 µl of anhydrous ethanol, vortex to mix, and centrifuge momentarily to collect the solution to the bottom of the tube. Note: The addition of anhydrous ethanol may produce a white precipitate that will not affect subsequent experiments.13. Add all of the solution from step 12, including the precipitate, to the Spin Columns DM in the collection tube, or transfer the solution several times if it cannot be added all at once. centrifuge at 12,000 rpm for 1 minute, pour off the waste from the collection tube, and return the column to the collection tube.14. Add 500 µl Buffer GW1 to the adsorbent column (check that anhydrous ethanol has been added before use), centrifuge at 12,000 rpm for 1 min, pour off the waste liquid from the collection tube, and put the adsorbent column back into the collection tube.15. Add 500 µl Buffer GW2 to the adsorbent column (check that anhydrous ethanol has been added before use), centrifuge at 12,000 rpm for 1 minute, pour off the waste liquid in the collection tube, and put the adsorbent column back into the collection tube. Note: Step 15 can be repeated once if further improvement of DNA purity is required.16. Centrifuge at 12,000 rpm for 2 minutes and pour off the waste liquid in the collection tube. Leave the column at room temperature for a few minutes and dry thoroughly. Note: The purpose of this step is to remove residual ethanol from the adsorbent column; ethanol residue can interfere with subsequent enzymatic reactions (digestion, PCR, etc.).17. Place the adsorbent column in a new centrifuge tube (supplied), add 50 µl of Buffer GE to the center of the adsorbent column overhang, let stand at room temperature for 5 minutes, centrifuge at 12,000 rpm for 1 minute, collect the DNA solution, and store the DNA at -20 °C. Attention:1）If the downstream experiments are sensitive to pH or EDTA, sterilized water can be used for elution. The pH value of the eluent has a great influence on the elution efficiency. If the eluent is made of water, the pH value should be 7.0-8.5 (the pH value of water can be adjusted to this range with NaOH), and the elution efficiency is not high when the pH value is lower than 7.0.2）Incubation at room temperature for 5 minutes prior to centrifugation increases yield.3）If the final concentration of DNA is to be increased, the DNA eluate obtained in step 17 can be re-spiked onto the adsorbent membrane and step 17 repeated. 4）DNA stored in water will be affected by acidic hydrolysis. For long-term storage, it is recommended to elute with Buffer GE and store at -20℃... Read More | 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 |