| Description | The content of this cell is too long for an XLSX file (more than 32767 characters). Please use the CSV format for this export | Product content:D665967Component200 TStorageD665967ABuffer PB120 mLRTD665967BBuffer PS60 mLRTD665967CBuffer PW (concentrate)25 mLRTD665967DBuffer EB30 mLRTD665967ESpin Columns DM with Collection Tubes200 EART Product Introduction: This reagent kit adopts a new silicon-based membrane technology and Product content:D665967Component200 TStorageD665967ABuffer PB120 mLRTD665967BBuffer PS60 mLRTD665967CBuffer PW (concentrate)25 mLRTD665967DBuffer EB30 mLRTD665967ESpin Columns DM with Collection Tubes200 EART Product Introduction: This reagent kit adopts a new silicon-based membrane technology and reagent formula. Through a rapid and simple three-step process of binding, washing, and elution, 100 bp-10 kb DNA fragments can be purified and recovered from PCR products or enzyme reaction solutions (enzyme cutting, linking, probe labeling, etc.). Each adsorption column can adsorb up to 10 kb of DNA fragments µ G DNA, while minimizing impurities such as primers, oligonucleotides, enzymes, etc. The purified and recovered DNA has high purity and concentration, good integrity, and high recovery rate, and can be directly used for molecular biology experiments such as sequencing, linking and transformation, labeling, and in vitro transcription.Self prepared reagent: anhydrous ethanol.Preparation and important precautions before the experiment:1. All components can be stably stored in a dry, room temperature (15-30 ℃) environment for 1 year, and can be stored at 2-8 ℃ for longer periods of time. When the solution is stored at low temperature, it should be left at room temperature for a period of time before use, and then restored to room temperature before use.2. This reagent kit can selectively recover all DNA fragments from the solution. If you need to selectively recover specific fragments while removing other fragments of different sizes, please choose our company's gel recovery reagent kit.3.Before the first use, anhydrous ethanol should be added to the Buffer PW according to the instructions on the reagent bottle label.4. Before use, please check if there is any crystallization or precipitation in the Buffer PB. If there is any crystallization or precipitation, you can take a water bath at 37 ℃ for a few minutes to restore clarity.5. The recovery efficiency is related to the initial amount of DNA and the elution volume. The smaller the initial amount, the smaller the elution volume, and the lower the recovery rate.6. All centrifugation steps can be performed at room temperature.Operation steps:1. Estimate the volume of DNA reaction solution, add 5 times the volume of Buffer PB, and mix thoroughly (without removing paraffin or mineral oil).Note: 1) If the DNA reaction system is 50 µ l (excluding paraffin oil volume), add 250 µ l Buffer PB.2) After adding Buffer PB, check the pH value of the solution. If the pH value is greater than 7.5, add 10-30 to it µ 3 M sodium acetate (pH 5.0) was used to adjust the pH value to 5-7.2. Column balance: Add 200 to the spin columns DM that have been loaded into the collection tube µ Centrifuge at 13000 rpm (~16200 × g) for 1 minute, discard the waste liquid in the collection tube, and place the adsorption column back into the collection tube.3. Add the solution obtained in step 1 to the adsorption column that has been loaded into the collection tube, let it stand at room temperature for 1 minute, centrifuge at 13000 rpm for 30-60 seconds, discard the waste liquid in the collection tube, and place the adsorption column in the collection tube.Attention: The volume of the adsorption column is 750 µ l. If the sample volume is greater than 750 µ l, it can be added in batches.4. Add 500 µ l of Buffer PW to the adsorption column (please check if anhydrous ethanol has been added before use), centrifuge at 13000 rpm for 30-60 seconds, discard the waste liquid in the collection tube, and place the adsorption column in the recovery tube.Note: If purified DNA is used for salt sensitivity experiments (such as flat end ligation experiments or direct sequencing), it is recommended to add Buffer PW and let it stand for 2-5 minutes before centrifugation.5.13000 rpm for 1 minute and discard the waste liquid from the collection tube. Place the adsorption column at room temperature for a few minutes to thoroughly air dry.Note: The purpose of this step is to remove residual ethanol from the adsorption column, which can affect subsequent enzymatic reactions (such as enzyme digestion, PCR, etc.). To ensure that downstream experiments are not affected by residual ethanol, it is recommended to open the cover of the adsorption column and place it at room temperature for a few minutes to thoroughly dry the residual ethanol in the adsorbent material at the bottom.6. Place the adsorption column into a new centrifuge tube (provided by oneself), add 30-50 µ l Buffer EB to the middle position of the adsorption membrane by hanging droplets, and let it stand at room temperature for 1 minute. Centrifuge at 13000 rpm for 1 minute and collect DNA solution- Store DNA at 20 ℃.Attention:1) The pH value of the eluent has a significant impact on the elution efficiency. If water is used as the eluent, its pH value should be ensured to be between 7.0-8.5 (the pH value of water can be adjusted to this range using NaOH).2) To improve the recovery of DNA, the solution obtained by centrifugation can be added back to the adsorption column, left at room temperature for 2 minutes, and centrifuged at 13000 rpm for 1 minute.3) The elution volume should not be less than 30 µ l. A small volume will affect the recovery efficiency... Read More | Product content:ComponentG665836100 rxnsG665836100 rxnsG665836100 rxns2×GoldStar Probe One Step Buffer1.4 ml1.4 ml1.4 mlGoldStar Probe One Step EnzymeMix100 µl100 µl100 µl50×Low ROX-50 µl-50×High ROX--50 µlRNase-Free Water1.5 ml1.5 ml1.5 mlProduct IntroductionProduct content:ComponentG665836100 rxnsG665836100 rxnsG665836100 rxns2×GoldStar Probe One Step Buffer1.4 ml1.4 ml1.4 mlGoldStar Probe One Step EnzymeMix100 µl100 µl100 µl50×Low ROX-50 µl-50×High ROX--50 µlRNase-Free Water1.5 ml1.5 ml1.5 mlProduct Introduction：This product is a specialized reagent kit for one-step Real Time RTqPCR using probe methods (TaqMan, Molecular Beacon, etc.). When using this product for Real Time RT qPCR reaction, reverse transcription and quantitative PCR are requiredConducted in the same reaction system, there is no need to add reagents or open the tube cap during the reaction process, avoiding contaminationThis has improved the efficiency of the experiment. This product has high detection sensitivity, strong fluorescence signal, and high signal-to-noise ratio, making it very suitable forDetection of RNA viruses and other trace amounts of RNA. The special buffering system it contains can enable reverse transcriptase to interact with DNA polymeraseMaximize the effectiveness and improve reaction efficiency. By using this product, a wider linear range can be obtained, which is beneficial for the target base Due to more accurate quantification, good repeatability, and high reliability.ROX dye is used to correct the fluorescence signal error generated between wells in quantitative PCR instruments, and is generally used for ABIReal Time PCR amplification equipment from companies such as Stratagene. The excitation optical systems of different instruments vary, thereforeThe concentration of ROX dye must be matched with the corresponding fluorescence quantitative PCR instrument.matters needing attention：1. Before using the reagents in this reagent kit, please gently mix them upside down to avoid foaming as much as possible, and use them after brief centrifugation. 2. This product uses RNA as a template for one-step RT-PCR experiments, and RNase contamination should be avoided during the operation process,2.It is recommended to perform RNA operations in a dedicated area, using specialized instruments and consumables. Operators should wear masks and disposable gloves and frequently change gloves. Experimental consumables should be treated with a 0.1% DEPC (diethyl pyrocarbonate) aqueous solution at 37 ℃ for 12 hours and sterilized under high pressure for 30 minutes before use.3. Each reagent in this kit should avoid repeated freezing and thawing as much as possible, as repeated freezing and thawing may lead to a decrease in product performance.4. This reagent kit must use specific primers, and the selection of primers can be based on specific experiments. The quality of primer design directly affects the results of RT qPCR reaction. When designing primers, GC content, primer length, and primer should be considered Due to factors such as location, secondary structure of PCR products, it is recommended to use professional primer design software for design.5. It is recommended to use specific probes in this reagent kit and use professional design software for design. Usage: The following examples are typical reaction systems and conditions. In practical operation, corresponding improvements and optimizations should be made based on the differences in template, primer structure, and target fragment size. (Please prepare the reaction solution on ice)1. Dissolve the RNA template, primers, 2xGoldStar Probe One Step Buffer, GoldStar Probe One Step EnzymeMix, and RNase Free Water and place them on ice for later use.2. PCR reaction system: reagent 25 µl Reaction system final concentration 2×GoldStar Probe One Step Buffer 12.5 µl 1× Forward Primer，10 µM 0.5 µl 0.2 µM 1） Reverse Primer，10 µM 0.5 µl 0.2 µM 1） Probe ，10 µM 0.5 µl 0.2 µM 2） GoldStar Probe One Step EnzymeMix 1.0 µl / RNA Template X µl 10 pg – 100 ng3） 50×Low ROX or High ROX （optional）4） 0.5 µl 1× RNase-Free Water up to 25 µl /Note: 1) Typically, the primer concentration is 0.2 µ M can achieve good results, ranging from 0.1 to 1.0 µ M serves as a reference for setting the range. 2) The concentration of the probe used is related to the fluorescent quantitative PCR instrument used, the type of probe, and the type of fluorescent labeling substance. Please refer to the instrument manual or the specific usage requirements of each fluorescent probe for concentration adjustment during actual use.3) The amount of RNA templates is usually based on 10 pg-100 ng as a reference. Due to the different copy numbers of target genes contained in templates of different species, gradient dilution can be applied to the templates to determine the optimal template usage.4) The excitation optical systems of different instruments vary, and depending on the instrument used for fluorescence quantification, 50 x Low ROX or 50 x High ROX can be added.3. Mix well, centrifuge briefly, and collect the solution to the bottom of the tube.4. RT-PCR reaction conditions steps temperature time / Reverse Transcription 45℃ 10 min / PCR pre denaturation 95℃ 10 min / denaturation 95℃ 15s 30-40cycle Annealing/Extension 60℃ 45s 30-40cycleAttention:1) The hot start enzyme used in this product must be activated under pre denaturation conditions of 95 ℃ and 5-10 minutes.2) It is recommended to use a two-step PCR reaction program. If good experimental results cannot be obtained due to the use of primers with lower Tm values, a three-step PCR amplification can be attempted. The annealing temperature should be set within the range of 56 ℃ -64 ℃ as a reference... Read More | Products contentN665737Component24 T96 TStorageN665737ATPS V50 168 µL672 µL-20℃. Avoid freeze/thaw cycle.N665737B5×FA Reaction Buffer96 µL384 µL-20℃. Avoid freeze/thaw cycle.N665737CTS Buffer72 µL288 µL-20℃. Avoid freeze/thaw cycle.N665737D2×Products contentN665737Component24 T96 TStorageN665737ATPS V50 168 µL672 µL-20℃. Avoid freeze/thaw cycle.N665737B5×FA Reaction Buffer96 µL384 µL-20℃. Avoid freeze/thaw cycle.N665737CTS Buffer72 µL288 µL-20℃. Avoid freeze/thaw cycle.N665737D2×PCR Mix600 µL2×1.2 mL-20℃. Avoid freeze/thaw cycle. * This kit is suitable for human genomic DNA library construction, the starting template DNA input is 5 ng. We also have transposase library construction kits for 50 ng and 1 ng of human genomic DNA starting, in order to get a higher quality library, it is recommended to use different kits for different starting amount of DNA. Products IntroductionThis kit is developed for Illumina's high-throughput sequencing platform and provides the enzyme premix system and reaction buffer for genomic DNA library construction, including all components except PCR primers. Compared with the traditional library construction kits, this kit adopts the new transposase method for library construction, which can complete DNA fragmentation, end repair and junction reaction in one simple enzymatic reaction, significantly reducing the amount of template, reducing the number of experimental steps, and shortening the time of library construction; it adopts the high-fidelity DNA polymerase for library enrichment, and the preference-free PCR amplification can expand the coverage area of the sequence, which can be used for efficient and effective sequencing. The use of high-fidelity DNA polymerase for library enrichment and preference-free PCR amplification broadens the coverage area of the sequence and enables efficient preparation of DNA libraries for Illumina's second-generation sequencing platform. The kit is suitable for use with a starting template DNA input of 5 ng, and all reagents in the kit have been subjected to stringent quality control and functional validation to maximize the stability and reproducibility of library construction. Product Features● DNA fragmentation and junction ligation in one step.● Ultra-fidelity amplification minimizes amplification preference.Provide your own instruments, kits and consumables1. Magnetic frame: DynaMagTM-2 is recommended.2. DNA purification and recovery kit: It is recommended to use DNA purification and recovery kit by magnetic bead method.3. Library PCR primer kit: It is recommended to use transposase method for second generation sequencing multi-sample primer kit.4. Anhydrous ethanol, deionized water (pH between 7.0 and 8.0).5. Reaction tubes: It is recommended to use low adsorption PCR tubes and 1.5 ml centrifuge tubes. Tips: It is recommended to use high quality filter tips to prevent contamination of kits and library samples. Pre-experiment Preparation and Important Notes1. Avoid repeated freezing and thawing of reagents.2. PCR products are easily contaminated due to improper operation, resulting in inaccurate results. It is recommended to isolate the PCR reaction system preparation area from the PCR product purification area, and to use special pipettes to clean the experimental areas at regular intervals.3. Bead purification: the beads should be equilibrated to room temperature before use, all operations on the beads should be carried out at room temperature, 80% ethanol should be dispensed freshly, the beads should be rinsed and dried until the surface is free of liquid reflections and has a frosted appearance, insufficient drying of the beads will cause ethanol residue that will affect the subsequent experiments, and over-drying of the beads will affect the efficiency of DNA recovery.4. The kit is suitable for human genomic DNA library construction, if the DNA sample is a PCR product, it should be ensured that its length>.500 bp, since transposases do not work on DNA ends, it is recommended to extend the PCR product by 50-100 bp at each end of the PCR product to avoid low coverage of the ends for sequencing. Sample PreparationDNA purity requirements: A260/A280 = 1.8-2.0. Sample DNA: dissolve in ultrapure water. DNA Quantification: Too much or too little DNA will affect the quality of the library. It is recommended to use Nano to test the purity of the genomic DNA and then use Qubit to test the concentration of the genome (do not use any absorbance-based assay for template quantification). Schematic diagram of DNA banking processprocedureDNA fragmentation, junction reaction 1. Add the following reagents to a 200 µl PCR tube: 2. Mix by gently blowing with a pipette and centrifuge briefly so that all components are collected at the bottom of the tube.3. Place the above PCR tubes in the PCR instrument with the hot cap on and program the reaction as follows: inactivation reactionAfter the DNA is fragmented, the enzyme is still in a high active state, so it should be removed from the PCR instrument immediately and terminated by adding the Reaction Termination Buffer, in order to prevent the DNA from being fragmented too much and resulting in smaller library fragments.1. Add 3 µl of TS Buffer to the PCR tube containing the fragmentation product.2. Mix by gently blowing with a pipette and centrifuge briefly so that all components are collected at the bottom of the tube.3. Incubate at room temperature for 5 min, or if the room temperature is too low, place the reaction on a PCR instrument at 25°C with the thermal cover closed.1. Add the following reagents to a 200 µl PCR tube.2. Mix by gently blowing with a pipette and centrifuge briefly so that all components are collected at the bottom of the tube.3. Place the above PCR tubes in the PCR instrument with the hot cap on and program the reaction as follows Selective recovery of library DNA fragmentsIt is recommended to use CombiVision Magnetic Beads DNA Purification and Recovery Kit for selective recovery of DNA fragments. When different sizes of DNA fragments are required, the amount of magnetic beads used is different, please refer to the attached table for the specific amount of magnetic beads used.(If using other brands of magnetic beads, you need to figure out the optimal amount of magnetic beads by yourself).Note: Amplification products can also be fragment length sorted and purified using the Gum Recovery Kit. If there is no special requirement for library length distribution, amplification products can also be purified directly from DNA fragments without selective recovery of DNA fragments as described on page 4 of the manual.1. CMPure should be equilibrated at room temperature for 30 min after shaking and mixing before use.2. Transfer the PCR products to a 1.5 ml centrifuge tube, rehydrate to 100 µl, add several volumes of magnetic beads equilibrated to room temperature, vortex for 5 seconds, and let stand at room temperature for 5 minutes.3. Centrifuge briefly, place the tube on a magnetic rack to separate the beads from the supernatant until the solution is clear, and carefully aspirate the supernatant and transfer it to a new 1.5 ml centrifuge tube.Note: Do not discard the top clear.4. Add several volumes of magnetic beads to the supernatant, vortex and shake for 5 seconds, then let stand at room temperature for 5 minutes.5. Centrifuge briefly, place the tube on a magnetic rack to separate the beads from the supernatant until the solution is clear, carefully aspirate the supernatant and discard it, avoiding contact with the beads that have bound the target DNA.Note: Do not discard the beads.6. Continue to keep the centrifuge tube fixed on a magnetic rack and add 200 µl of freshly prepared 80% ethanol to the tube and allow to stand at room temperature for 30 seconds, carefully discarding the supernatant.Note: When adding ethanol, the liquid must not be blown directly onto the beads.7. Repeat step 6 once.8. Keep the centrifuge tube fixed on a magnetic rack and leave to dry at room temperature until the surface of the beads is slightly cracked, add 20 µl of ddH2O to solubilize.Note: Do not over-dry the beads as this may affect the elution efficiency.9. Remove the centrifuge tube from the magnetic rack, vortex to completely resuspend the beads, and allow to stand at room temperature for 5 minutes. Centrifuge briefly, place the tube on the magnetic rack until the solution is clear, and transfer the supernatant solution to a new centrifuge tube. Table: Suggested amount of magnetic beads for different segment selection recovery Library DNA fragment purificationWe recommend the use of the Century Magnetic Bead Method DNA Purification and Recovery Kit.1. CMPure should be equilibrated at room temperature for 30 min after shaking and mixing before use.2. 50 µl of magnetic beads equilibrated to room temperature were added to the PCR product, vortexed and shaken for 5 seconds, and then left to stand at room temperature for 5 minutes.3. Centrifuge briefly, place the tube on a magnetic rack to separate the beads from the supernatant solution until the solution is clear (approximately 3-5 minutes), carefully aspirate the supernatant and discard it, avoiding contact with the beads that have bound the target DNA. Note: Do not discard the beads.4. Continue to keep the centrifuge tube fixed on a magnetic rack and add 200 µl of freshly prepared 80% ethanol to the centrifuge tube and allow to stand at room temperature for 30 seconds, carefully discarding the supernatant.Note: When adding ethanol, the liquid must not be blown directly onto the beads.5. Repeat step 4.6. Keep the centrifuge tube fixed on a magnetic rack and leave to dry at room temperature until the surface of the beads is slightly cracked, add 25 µl of ddH O to solubilize.Note: Do not over-dry the beads as this may affect the elution efficiency.7. Remove the tube from the magnetic rack, vortex to completely resuspend the beads, and allow to stand at room temperature for 5 minutes. Centrifuge briefly, place the tube on the magnetic rack until the solution is clear, and transfer the supernatant solution to a new tube. Library quality controlDetermination of library concentrationIn order to obtain high-quality sequencing results, accurate quantification of DNA libraries is required, and the first recommendation is to use Real-timePCR methods are used for absolute quantification of DNA libraries. Additionally, fluorescent dye methods such as the Qubit method or the fluorescent dye picogreen method can be used; do not use quantification methods based on absorbance measurements here. The following approximate formula can be used to convert the molar concentration of the DNA library. Library fragment distributionThe prepared DNA libraries can be detected by agarose gel electrophoresis or Agilent 2100 Bioanalyzer.Range of segment length distributions... 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 |