| Description | Product content R669871Component50 TStorageR669871ADNase I1000 U-20℃. Avoid freeze/thaw cycle.R669871B10×Reaction Buffer1mL-20℃. Avoid freeze/thaw cycle. R669871CBuffer DS30 mLRTR669871DBuffer GTL15 mLRTR669871EBuffer GL25 mLRTR669871FProteinase K12.5 mgRTR669871GProteinase K Product content R669871Component50 TStorageR669871ADNase I1000 U-20℃. Avoid freeze/thaw cycle.R669871B10×Reaction Buffer1mL-20℃. Avoid freeze/thaw cycle. R669871CBuffer DS30 mLRTR669871DBuffer GTL15 mLRTR669871EBuffer GL25 mLRTR669871FProteinase K12.5 mgRTR669871GProteinase K Storage Buffer1.25 mLRTR669871HBuffer RW140 mLRTR669871IBuffer RW2 (concentrate)11 mLRTR669871JRNase-Free Water10 mLRTR669871KSpin Columns RS with Collection Tubes50 setsRTR669871LRNase-Free Centrifuge Tubes (1.5 mL)50 EART Product IntroductionThis kit is suitable for effectively purifying total RNA from formalin fixed and paraffin embedded tissues. Suitable for extracting total RNA with improved purity from paraffin embedded tissues or sections less than 30mg. This kit does not require the use of phenol/chloroform extraction or isopropanol precipitation, and can complete the extraction of multiple samples within one hour. This product uses specially optimized lysis solution and protease K to release RNA from formalin fixed or tissue slice samples without overnight operation; After digestion, the sample is incubated at a higher temperature to remove the inhibitory effect caused by formalin cross-linking, effectively releasing RNA from tissue slices and avoiding endangering RNA integrity; The optimized buffer system allows RNA in the lysis solution to specifically bind to the silica gel adsorption membrane, while other pollutants can flow through the membrane; It can be effectively removed through rinsing steps, and the washed RNA can be directly used for experiments such as RT-PCR, Real Time PCR, and Western blot analysis.Self prepared reagents: anhydrous ethanol (newly opened or dedicated for RNA extraction), 10mM PBS (pH 7.4).Preparation and important precautions before the experiment1. Add 0.625ml Protein K Storage Buffer to Protein K to dissolve it and store at -20 ℃. The prepared Protein K should not be left at room temperature for a long time to avoid repeated freeze-thaw cycles, which may affect its activity.2. To prevent RNase pollution, attention should be paid to the following aspects:1) Use RNase free plastic products and gun heads to avoid cross contamination.2) Glassware should be dry baked at a high temperature of 180 ℃ for 4 hours before use, while plastic containers can be soaked in 0.5M NaOH for 10 minutes, thoroughly rinsed with water, and then sterilized under high pressure.3) Prepare the solution using water without RNase.4) Operators should wear disposable masks and gloves, and change gloves frequently during the experiment.3. After obtaining the sample, it should be fixed in 4% -10% formalin as soon as possible, with a suitable fixation time of 14-24 hours. Excessive time can lead to RNA breakage and affect downstream experiments.4. Ensure that the sample before embedding is thoroughly dehydrated, as residual formalin will inhibit the action of Protein K.5. Before the first use, anhydrous ethanol should be added to Buffer RW2 according to the instructions on the reagent bottle label.Before use, please check if there is any crystallization or precipitation in Buffer GTL, Buffer GL, and Buffer DS. If there is any crystallization or precipitation, please dissolve Buffer GTL, Buffer GL, and Buffer DS again in a 56 ℃ water bath.Operation steps1. Sample processing1a. Paraffin embedded sample: Use a surgical knife to trim off excess paraffin from the tissue block, expose the tissue, and cut into 5-10 µ m thin slices.Attention: If the surface of the sample has already been exposed to air, please discard 2-3 pieces that come into contact with the air and do not use them.1b. Samples in fixed solutions such as formalin: Take approximately 20mg of the sample, cut it into small pieces, place it in a centrifuge tube, and add 500 µ 10mM PBS (PH7.4), vortex oscillation, centrifugation at 12000 rpm (~13400 × g) for 1 minute, discard the supernatant, repeat 3 times, and proceed directly to step 3.2. Choose option A or option B to remove paraffinOption AA1. Take approximately 1 × 1cm2 of slices (4-5 slices in total) and place them in a centrifuge tube (prepared by oneself), then add 500 slices µ L Buffer DS, vortex oscillation for 10 seconds. Incubate at 56 ° C for 3 minutes.Centrifuge at A2.12000 rpm for 2 minutes, be careful to discard the supernatant and avoid attracting sediment.Option BB1. Take approximately 4-5 slices of approximately 1 × 1 cm2 and place them in a centrifuge tube (self prepared). Add 1ml of xylene, cover the tube tightly, and vortex for 10 seconds.B2.Centrifuge at 12000 rpm for 2 minutes, be careful to remove the supernatant and avoid removing sediment.B3. Add 1ml of anhydrous ethanol, vortex and shake well. Centrifuge at 12000 rpm for 2 minutes, discard the supernatant, and be careful not to absorb or discard the sediment.B4. Open the tube cover and incubate at room temperature or up to 37 ° C for 10 minutes until there is no ethanol residue.3. Add 150µ L Buffer GTL, resuspended precipitation; Join 10µl Protein K, vortex oscillation mixing.4.Incubate at 56 ℃ for 15 minutes until the sample is completely dissolved. Incubate at 80 ℃ for 15 minutes. Short centrifugation allows the solution on the tube wall to be collected to the bottom of the tube.Note: 1) The purpose of this step is to repair nucleic acids denatured by formaldehyde. Incubating at a high temperature or for too long may cause RNA breakage, resulting in RNA fragments.2) The sample incubated at 56 ℃ can be placed at room temperature until the temperature of the water or dry bath reaches 80 ℃, and then the sample can be incubated at 80 ℃.5. Place on ice for 3 minutes, centrifuge at 12000 rpm for 15 minutes, transfer the supernatant to a new centrifuge tube, be careful not to suck sediment.6. Add 320 to the supernatant µ L Buffer GL, vortex oscillation thoroughly mixed.7. Join 720 µ Mix anhydrous ethanol thoroughly with vortex oscillation.Attention: After adding anhydrous ethanol, there may be a small amount of precipitate precipitation, but it does not affect subsequent operations.8. Add all the solutions obtained in step 7 to the spin columns RS that have been loaded into the collection tube. If the solution cannot be added at once, it can be transferred multiple times. Centrifuge at 12000 rpm for 1 minute, discard the waste liquid in the collection tube, and place the adsorption column back into the collection tube.Optional steps: If genomic DNA needs to be removed, the following steps can be followeda. Add 350 to the adsorption column µ L Buffer RW1, centrifuge at 12000 rpm for 1 minute, discard the waste liquid, and place the adsorption column back into the recovery manifold.b. Preparation of DNase I mixture: Take 52 µ Add 8 RNase Free Water to it µ 10 x Reaction Buffer and 20 µ DNase I (1U/ µ l) Mix well and prepare to a final volume of 80 µ The reaction solution of L.c. Add 80 µ l of DNase I mixture directly to the adsorption column and incubate at 20-30 ℃ for 15 minutes.d. Add 350 to the adsorption column µ L Buffer RW1, centrifuge at 12000 rpm for 1 minute, discard the waste liquid, and place the adsorption column back into the recovery manifold.9. Add 500 to the adsorption column µ Buffer RW2 (check if anhydrous ethanol has been added before use), centrifuge at 12000 rpm for 1 minute, discard the waste liquid in the collection tube, and place the adsorption column back into the collection tube.10. Repeat step 9.Centrifuge at 11.12000 rpm for 2 minutes 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 will affect subsequent enzymatic reactions (such as enzyme digestion, PCR, etc.).12. Place the adsorption column in a new RNase free centrifuge tube, and add 20-50µl to the middle of the adsorption column in the air Place RNase Free Water at room temperature for 2-5 minutes, centrifuge at 12000 rpm for 1 minute, collect RNA solution, and store RNA at -20 ℃.Note: 1) The volume of RNase Free Water should not be less than 20 µ l. Small volume affects the recovery rate. 2) If you want to increase RNA production, you can use 20-50 µ Repeat step 12 for the new RNase Free Water.3) If you want to increase the RNA concentration, you can add the obtained solution back to the adsorption column and repeat step 12... Read More | H665581 Component 100 T Storage H665581A gDNA Eraser 50 µL -20℃. Avoid freeze/thaw cycle. H665581B 10×gDNA Eraser Buffer 120 µL -20℃. Avoid freeze/thaw cycle. H665581C HiFiScript, 200 U/µL 100 µL -20℃. Avoid freeze/thaw cycle. H665581D 5×ScriptRT H665581 Component 100 T Storage H665581A gDNA Eraser 50 µL -20℃. Avoid freeze/thaw cycle. H665581B 10×gDNA Eraser Buffer 120 µL -20℃. Avoid freeze/thaw cycle. H665581C HiFiScript, 200 U/µL 100 µL -20℃. Avoid freeze/thaw cycle. H665581D 5×ScriptRT Buffer 500 µL -20℃. Avoid freeze/thaw cycle. H665581E Primer Mix 120 µL -20℃. Avoid freeze/thaw cycle. H665581F RNase-Free Water 2×1 mL -20℃. Avoid freeze/thaw cycle.Product IntroductionThis product is a kit for removing genomic DNA for reverse transcription. The kit removes genomic DNA in 2 minutes at 42°C. Since the reverse transcription reagent contains a component that inhibits gDNA Eraser, cDNA can be synthesized directly by reverse transcription of gDNA Eraser-treated samples.The kit is equipped with a new high-efficiency reverse transcription enzyme, HiFiScript, with novel mutation sites that dramatically increase the transcriptional activity of the enzyme, resulting in higher efficiency and yield of cDNA first-strand synthesis. The first strand of cDNA can be synthesized with higher efficiency and yield, and the first strand of cDNA can be synthesized from pg total RNA or mRNA. If the reverse transcription product cDNA is used for downstream fluorescence quantitative detection, the reverse transcription reaction can be completed at 42℃ in 15 minutes. This kit is suitable for the synthesis of first-strand cDNA and subsequent RT-PCR, RT-qPCR, and the construction of full-length cDNA libraries.Product Features1. Rapid genome removal: contains gDNA Eraser for genomic DNA removal, which removes genomic DNA in just 2 minutes.2. Rapid reverse transcription: 15 minutes to obtain fluorescent quantitative PCR template cDNA first strand synthesis.3. High sensitivity: cDNA first strand can be synthesized using pg-level total RNA or mRNA templates.4. Highly efficient reverse transcription: Novel mutation sites dramatically increase enzyme activity, resulting in higher yields of cDNA.matters needing attention1. During operation, RNase contamination should be avoided to prevent RNA degradation or cross-contamination in the experiment. It is recommended that operators wear masks and disposable gloves and change the gloves frequently, and use specialized instruments and consumables.2. The reverse transcription system is prepared and operated on ice to prevent degradation of RNA. Store the kit enzymes at -20ºC as soon as possible after use and try to avoid repeated freezing and thawing.3. The reaction system can be scaled up to a maximum of 1 µg of total RNA in 10 µl of reaction system.4. Primer Mix is prepared by Oligo(dT) and Random primer, and Oligo-dT Primer or Gene Specific Primer can also be used according to the experimental needs.5. If the amount of starting RNA is less than 50ng, it is recommended to add RNAase inhibitor (RNasin).6. For RNA templates with complex secondary structures, it is recommended to incubate the template RNA at 65°C for 5 minutes immediately on ice prior to the manipulation step and centrifuge briefly before proceeding to the next step.UsageThaw template RNA on ice; place kit components on ice immediately after thawing at room temperature. Each solution was mixed by vortexing and shaking before use and briefly centrifuged.I. Genomic DNA removal reactions1. Prepare the reaction system according to the following table on ice in a total volume of 10 µl. To ensure the accuracy of the reaction solution preparation, prepare the premixed system in the amount of reaction number + 2 before dispensing it into each reaction tube and finally adding the RNA sample.Note: 1) If the amount of total RNA is greater than 1µg, scale up the reaction system proportionally. If the amount of starting RNA is less than 50ng, it is recommended to add RNAase inhibitor (RNasin).2. Mix by vortex shaking and centrifuge briefly so that the solution on the walls of the tube collects at the bottom.3. Incubate at 42°C for 2 minutes (this can be extended to 30 minutes for room temperature reactions).4．At the end of the reaction, centrifuge briefly and place on ice to cool.II. Reverse transcription reaction1. Prepare the reaction system on ice according to the following table. In order to ensure the accuracy of the reaction solution configuration, first prepare a premixed solution in the amount of number + 2, and then dispense 10 µl into each reaction tube, take 10 µl of the prepared premixed solution and add it to the reaction tube of step 1 where the de-etching of the genome has been completed.Note: 1) Oligo-dT Primer or Gene Specific Primer can be used according to the needs of the experiment, it is recommended to use 50 pmol of Oligo-dT Primer or 2 pmol of Gene Specific Primer for 20 µl reaction system.2. Mix well and centrifuge briefly so that the solution on the walls of the tube collects at the bottom.3. cDNA synthesis reaction conditions:1) If fluorescent quantitative PCR assay is performed downstream, incubate at 42°C for 15 minutes and 85°C for 5 minutes.2) If downstream for normal PCR assay, incubate at 42°C for 30-50 minutes and 85°C for 5 minutes. Note: For templates with complex secondary structure or high GC content, the reverse transcription temperature can be increased to 50°C to enhance reverse transcription efficiency.4. At the end of the reaction, centrifuge briefly and place on ice before proceeding with subsequent PCR or fluorescence quantitative PCR, or place at -20°C if prolonged storage is required.Note: When performing Real-time PCR reactions, the amount of reverse transcription product added should not exceed 1/10 of the total volume of the PCR reaction... Read More | DescriptionProvides an inert environment to run oxygen sensitive cross-coupling reactions in a laboratory fume hood.Designed to be used with KitAlysis High-Throughput Screening Kits and KitAlysis 24-Well Reaction Block | Product content N665859Component50 TStorageN665859ABuffer DS30 mLRTN665859BBuffer GTL15 mLRTN665859CBuffer GL15 mLRTN665859DBuffer GW1 (concentrate)13 mLRTN665859EBuffer GW2 (concentrate)15 mLRTN665859FBuffer TE10 mLRTN665859GProteinase K2×1.25 mLRTN665859HRNase A (100 mg/mL)0.4 Product content N665859Component50 TStorageN665859ABuffer DS30 mLRTN665859BBuffer GTL15 mLRTN665859CBuffer GL15 mLRTN665859DBuffer GW1 (concentrate)13 mLRTN665859EBuffer GW2 (concentrate)15 mLRTN665859FBuffer TE10 mLRTN665859GProteinase K2×1.25 mLRTN665859HRNase A (100 mg/mL)0.4 mLRTN665859ISpin Columns DF With Collection Tubes50 EA2-8℃N665859JCentrifuge Tubes (L-1.5 mL)50 EART Product IntroductionThis kit is suitable for the effective purification of genomic DNA from formalin-fixed, paraffin-embedded tissues.The product uses specially optimized dewaxing agent and lysis solution to release DNA from formalin-fixed or tissue sectioned samples, which does not involve the organic reagent xylene and does not need to be operated overnight; the digested samples are incubated at higher temperatures to remove formalin cross-linking of the free DNA, which can effectively improve the yield and purity of DNA; the optimized buffer system allows the inhibitors in the lysis solution to be specifically bound to the adsorbent membrane, which can be effectively removed by a two-step rinsing step. The optimized buffer system enables the DNA in the lysate to specifically bind to the adsorbent membrane, and the inhibitor is effectively removed by a two-step rinsing step, and finally eluted with low-salt buffer or water to obtain high-purity DNA.Meanwhile, configured with a high-efficiency microsorbent column, the elution volume can be as low as 20 µL.The purified DNA can be directly used for PCR, Real-time PCR, SNP Genotyping, STR genotyping, second-generation sequencing and pharmacogenomics research.The molecular weight of DNA isolated from formalin-fixed, paraffin-embedded samples is usually lower than that of DNA from fresh or frozen samples.The degree of DNA fragmentation depends on the type of sample, the duration of storage, and the conditions of fixation.Self-contained reagent: anhydrous ethanolPre-experiment Preparation and Important Notes1. After obtaining the sample, fix the sample in 4%-10% formalin as soon as possible, the fixation time should be 14-24 hours, too long a period of time will easily lead to genome breakage, affecting the downstream experiments. If the formaldehyde fixation time is too long or the sample has been stored for too long (> 1 year), it will easily lead to DNA integrity damage and unable to amplify long fragments.2. Ensure that the sample is thoroughly dehydrated before embedding; residual formalin will inhibit Proteinase K.3. Anhydrous ethanol should be added to Buffer GW1 and Buffer GW2 according to the instructions on the label of the reagent bottle before first use.4. Before use, please check Buffer GTL, Buffer GL and Buffer DS for any crystallization or precipitation. If there is any crystallization or precipitation, please re-dissolve Buffer GTL, Buffer GL and Buffer DS at 56℃ in a water bath.5. Preheat the water bath or thermostatic mixer to 56°C and keep the centrifuge at 25°C before starting the experiment.6. If downstream experiments are needed to reduce the low frequency of C>T:G>A transitions (artificial mutations) that occur to minimize the risk of false positives, 7 µL of UNG (1 U/uL) can be added after 1 hour of incubation at 90°C.Operation steps1. Sample processing:1a. Paraffin-embedded samples: Trim off excess paraffin from the tissue block with a scalpel to expose the tissue and then cut into 5-10µm slices. Take about 1×1cm2 slices (about 4-5 slices in total) and place them in a centrifuge tube (provided), add 160µL Buffer DS, vortex and shake for 10 seconds, then add 180µL Buffer GTL and 20µL Proteinase K, vortex and shake for 10 seconds. centrifuge the samples at 12,000rpm for 1 minute at 25℃.Note: 1) If the surface of the sample has been exposed to air, discard the 2-3 pieces that have been exposed to air and do not use them.2) DS will solidify below 18°C, and if it does it does not affect the following experiments.1b. Sample in formalin and other fixative: take about 20mg of sample, cut it into small pieces, place it in a centrifuge tube, add 500µL of 10mM PBS (PH7.4), vortex shaking, centrifuge at 12,000rpm for 1minute, discard the supernatant, and repeat 3 times. Add 180 µL Buffer GTL, 20 µL Proteinase K, vortex shaking to mix.2.56°C for 1 hour until the sample is completely dissolved. incubate at 90°C for 1 hour. centrifuge at 12,000 rpm, 25°C for 1 minute, and carefully pipette the lower aqueous phase (~180 µL) along the wall of the tube into a new centrifuge tube, trying to avoid aspirating the bottom precipitate and the upper layer of the wax solution.Note: 1) Samples can be left at room temperature after incubation at 56°C until the temperature of the water or dry bath reaches 90°C before placing the samples at 90°CIncubation.2) Optional step: add 7µL UNG (1U/µL), 50°C, 5min, no shaking. The purpose of this step is to minimize the risk of false positives by reducing the low-frequency occurrence of C>T:G>A transitions (artificial mutations) while effectively retaining the true occurrence of mutations.3. Optional step: If you need to remove RNA, you can lower the temperature of the sample to room temperature, then add 2µL of RNase A solution at a concentration of 100mg/mL, shake and mix well, and leave it at room temperature for 2 minutes.4. Add 20µL Proteinase K and incubate at 65℃, 450rpm for 15min.5. Add 200 µL of Buffer GL, mix well by vortexing and shaking, then add 200 µL of anhydrous ethanol and mix thoroughly by vortexing and shaking. Centrifuge briefly so that the solution on the wall of the tube collects at the bottom of the tube.Note: 1) Mix well immediately after adding Buffer GL and anhydrous ethanol.2) The addition of Buffer GL and anhydrous ethanol may produce a white precipitate that will not affect subsequent experiments.3) If more than one sample needs to be manipulated, the Buffer GL and anhydrous ethanol can be pre-mixed and spiked.6. Add all the solution obtained in step 5 to the adsorption columns (Spin Columns DF) that have been loaded into the collection tube, centrifuge at 25℃, 12000rpm for 2 minutes, pour out the waste liquid in the collection tube, and put the adsorption columns back into the collection tube.7. Add 500µL of Buffer GW1 to the adsorption column (check that anhydrous ethanol has been added before use), centrifuge at 12,000rpm for 1 minute, pour off the waste liquid in the collection tube, and put the adsorption column back into the collection tube.8. Add 500µL of Buffer GW2 to the adsorption column (check that anhydrous ethanol has been added before use), centrifuge at 12000rpm for 1 minute, pour off the waste liquid in the collection tube, and put the adsorption column back into the collection tube.Note: Step 8 can be repeated if further DNA purity is required.9.12 Centrifuge at 2000 rpm for 2 minutes and pour off the waste liquid in the collection tube. Leave the adsorption column at room temperature for several minutes to dry thoroughly.Note: The purpose of this step is to remove residual ethanol from the adsorption column; ethanol residue can interfere with subsequent enzymatic reactions.10. Place the adsorption column in a new 1.5 mL collection tube, add 20-100 µL of Buffer TE or sterilized water to the middle of the adsorption column overhanging the column, let it stand at room temperature for 2-5 minutes, centrifuge it at 12,000 rpm for 1 minute, and collect the DNA solution.-20°C to preserve DNA.Note: 1) The pH value of the eluent has a great influence on the elution efficiency, if water is used as the eluent should ensure that its pH value is 7.0-8.5, the pH value is lower than 7.0 when the elution efficiency is not high.2) If the final concentration of DNA is to be increased, the DNA eluate obtained in step 10 can be re-spiked onto the adsorbent membrane and left at room temperature for 2 minutes and centrifuged at 12,000 rpm for 1 minute... Read More | Product introduction：PMA qPCR live bacteria detection kit provides an effective means to detect bacterial activity. This kit provides a mixture of PMA dye and SYBR green dye based qPCR. The optimal amount of dye and the number of samples that can be processed may vary depending on the type ofProduct introduction：PMA qPCR live bacteria detection kit provides an effective means to detect bacterial activity. This kit provides a mixture of PMA dye and SYBR green dye based qPCR. The optimal amount of dye and the number of samples that can be processed may vary depending on the type of sample. PMA is a DNA binding dye with high affinity, especially with double stranded DNA. The dye itself has weak fluorescence, but it can emit brighter fluorescence after binding with nucleic acids. PMA is impermeable to the cell membrane, so it can selectively modify the DNA of dead cells with damaged membrane. After bllight (~464 nm) photolysis of PMA modified DNA, the photoreactive azido group on PMA is converted into highly reactive azene radical, which reacts with any hydrocarbon moiety near the DNA binding site to form a stable covalent nitrogen carbon bond, resulting in permanent DNA modification. This modification process will make the DNA insoluble, and it will be lost together with cell debris in the later genomic DNA extraction process. The unbound PMA remaining in the solution reacts with water molecules under strong light irradiation and decomposes into hydroxylamine compounds without cross-linking activity, so that it can no longer covalently bind DNA. Based on this characteristic of PMA, our company combines PMA and qPCR technology to form a new detection method - PMA qPCR, which is used for the screening of live bacteria. At present, the method has been validated in a variety of bacterial strains as well as yeast, fungi, viruses and parasites. The treatment of complex samples, such as feces or soil, may require optimization of sample dilution, dye concentration, and light treatment time. Treatment of diluted samples, such as water testing, may require filtration or concentration prior to dye treatment. Component： 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 ( used for the photolysis step after PMA modified DNA ) ;② Bacterial genomic DNA extraction kit ; 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 procedureNote : 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. 3. 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 : Product parameters：Pma: ex = 464 nm; Ex/em = 510/610 nm (following photolysis and reaction with dna/rna)Scope of application：Live bacteria detection Matters needing attention：1.Please instantaneously centrifuge the product to the bottom of the tube before use, and then carry out subsequent experiments ; 2.the kit components contain fluorescent dyes, and attention should be paid to avoiding light during use and preservation ; 3.For your safety and health, please wear experimental clothes and disposable gloves... Read More |