| Description | Product content C665709Component50 TStorageC665709ABuffer CL45 mLRTC665709BBuffer CB (concentrate)60 mLRTC665709CBuffer GW1 (concentrate)13 mLRTC665709DBuffer GW2 (concentrate)15 mLRTC665709EBuffer EBL10 mLRTC665709FProteinase K100 mgRTC665709GProteinase K Storage Buffer5 mLRTC665709HSpin Columns DFProduct content C665709Component50 TStorageC665709ABuffer CL45 mLRTC665709BBuffer CB (concentrate)60 mLRTC665709CBuffer GW1 (concentrate)13 mLRTC665709DBuffer GW2 (concentrate)15 mLRTC665709EBuffer EBL10 mLRTC665709FProteinase K100 mgRTC665709GProteinase K Storage Buffer5 mLRTC665709HSpin Columns DF with Collection Tubes50 EA2-8℃C665709ICentrifuge Tubes (L-1.5 mL)50 EART Product IntroductionThis kit is suitable for the extraction of free DNA from fresh or frozen serum, plasma, lymph fluid and other cell-free body fluids.This kit adopts centrifugal adsorption columns that can specifically bind nucleic acids and a unique buffer system.After the sample is lysed, the free DNA binds to the silica gel membrane under high salt conditions, and the free DNA elutes from the silica gel membrane at low salt and high pH. The product can handle liquid samples of 0.1-1 ml, and the elution volume of the configured high-efficiency micro adsorption column can be as low as 20 µl. The purified DNA is of high yield and quality, with maximum removal of proteins, pigments, lipids, and other inhibitors, and the rate of free DNA yield is highly dependent on the type of samples, storage conditions, time, and inter-individual variations. The quality of free DNA obtained from purification is stable and reliable, and can be directly used in molecular biology experiments such as PCR, fluorescence quantitative PCR and second generation sequencing.Self-contained reagents: anhydrous ethanol, isopropanol.Pre-experiment Preparation and Important NotesAdd 5 ml of Proteinase K Storage Buffer to Proteinase K to dissolve it and store it at -20℃. Do not leave the prepared Proteinase K at room temperature for a long time.Repeated freezing and thawing of the sample should be avoided, as this can lead to a decrease in extraction.This kit can extract 0.1-1 ml of liquid samples.Before use, please check Buffer CL, Buffer CB for crystallization or precipitation, if there is any crystallization or precipitation, please re-dissolve Buffer CL, Buffer CB by incubation at 56℃ in a water bath.Before first use isopropyl alcohol should be added to Buffer CB according to the instructions on the reagent bottle label, mixed well, and labeled on the reagent bottle label.Before the first use, anhydrous ethanol should be added to Buffer GW1 and Buffer GW2 according to the instructions on the label of the reagent bottle, mixed well, and labeled on the label of the reagent bottle.Preheat the water bath to 60°C before starting the experiment.The elution buffer Buffer EBL can be preheated to 60°C and used.Operation stepsAdd 20 µl of Proteinase K to the centrifuge tube (supplied).Add 200 µl of serum/plasma sample.Note: When the sample volume exceeds 200 µl, please increase the amount of Proteinase K, Buffer CL and Buffer CB reagents in equal proportions, and the specific amount of reagents added can be referred to the attached table.3. Add 160 µl Buffer CL, mix upside down and shake vigorously for at least 30 seconds.4. Incubate at 60°C for 30 minutes, during which time mixing was inverted several times.Note: Incubation of 200µl serum/plasma samples at 60°C for 10-15 minutes is sufficient.Add 360 µl of Buffer CB (check for addition of isopropanol before use) and shake until thoroughly mixed.Ice bath for 5 minutes and centrifuge briefly to concentrate the liquid on the walls and wall caps to the bottom of the tube.Add all of the solution obtained in step 6 to the adsorption columns (Spin Columns DF) that have been loaded into the collection tubes, and if the solution cannot be added all at once, it can be transferred in several times. centrifuge the columns at 12,000 rpm for 1 minute, pour off the waste solution from the collection tubes, and put the columns back into the collection tubes.Add 500µl of Buffer GW1 to the adsorbent column (check that anhydrous ethanol is added before use),centrifuge the column at 12,000rpm for 30 seconds, pour off the waste liquid in the collection tube, and put the adsorbent column back into the collection tube.Add 750 µl Buffer GW2 to the adsorbent column (check that anhydrous ethanol is added before use), centrifuge at 12,000 rpm for 30 seconds, pour off the waste liquid in the collection tube, and put the adsorbent column back into the collection tube.10. Add 750 µl of anhydrous ethanol to the adsorbent column and centrifuge at 12,000 rpm for 30 s. Pour off the waste liquid in the collection tube and put the adsorbent column back into the collection tube.11. Centrifuge at 12,000 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, which can interfere with the subsequent enzymatic reaction.12. Place the adsorption column in a new centrifuge tube, add 20-100 µl Buffer EBL or sterilized water to the middle part of the adsorption column overhanging the column, leave it at room temperature for 2-5 minutes, centrifuge at 12,000 rpm for 1 minute, collect the DNA solution, and store the DNA at -20℃.Note: 1) If the downstream experiment is sensitive to pH, you can use sterilized water for elution. 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 (you can use NaOH to adjust the pH value of water to this range), and the elution efficiency is not high when the pH value is lower than 7.0.2) Preheat the elution buffer BufferEBL to 60℃ and use it, and incubate it at room temperature for 5 minutes before centrifugation to increase the yield.3) If the final concentration of DNA is to be increased, the resulting solution can be reintroduced into the adsorption column and left at room temperature for 2-5 minutes and centrifuged at 12,000 rpm for 1 minute.4) Because DNA preserved in water will be affected by acidic hydrolysis, for long-term storage, it is recommended to elute it with Buffer EBL and store it at -20℃.Table: Recommended reagent additions for different sample sizes... Read More | 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 | The fluorescent dye PKH67 is suitable for conventional cell membrane labeling. It is a green fluorescent dye that can track cells in vitro and in vivo. It labels cells by binding to the lipid components of the membrane structure. PKH67 has low cytotoxicity, low fluorescence background, high fat The fluorescent dye PKH67 is suitable for conventional cell membrane labeling. It is a green fluorescent dye that can track cells in vitro and in vivo. It labels cells by binding to the lipid components of the membrane structure. PKH67 has low cytotoxicity, low fluorescence background, high fat solubility, can easily penetrate cell membranes, and has strong and stable green fluorescence. PKH67-labeled cells can be used for in vitro and in vivo proliferation studies, and have the function of not staining neighboring cells. In the process of cell division and proliferation, the fluorescence intensity of PKH67 will gradually decrease as the cells divide. The labeled fluorescence can be evenly distributed to the two sub-generation cells, so its fluorescence intensity is half that of the parent cell. According to this feature, It can be used to detect cell proliferation, cell cycle estimation and cell division, etc. The fluorescence of PKH67-labeled cells is very uniform, and the fluorescence distribution of sub-generation cells after division is also more uniform. In the process of cell division and proliferation, PKH67-labeled fluorescence can be evenly distributed between the two sub-generation cells, and the fluorescence intensity becomes half of that of the parent cell. According to the difference in fluorescence intensity, the undivided cells can be detected by flow cytometry. One time (1/2 the fluorescence intensity), the second time (1/4 the fluorescence intensity), three times (1/8 the fluorescence intensity), and more divisions of cells. PKH67 can detect splits up to six times or even more. In addition to the detection of cell proliferation, PKH67 can also be used for in vitro tracking of cells. After labeling, the fluorescence expression is stable in the cell, and the positive labeling rate is over 98%. The labeled cells have good morphology, which can effectively observe the cells in vitro. Induce differentiation; or inject labeled cells into the body, it can effectively show the migration and differentiation of transplanted cells in living tissues. PKH67-labeled cells can be used for in vivo observation for as long as several weeks. It is often used for in vivo cell detection experiments and experiments to observe long-term cell activity using fluorescence electron microscope. PKH67 is less toxic and does not affect cell proliferation. This method is simple to operate, does not use radioactive isotopes, and poses no safety hazards. You can get the desired experimental data faster, more accurately and more safely.Due to the longer length of the charcoal tail, internal studies have shown that PKH67 is less transferred between cells than PKH2. In in vivo studies using PKH1 and PKH2, the fluorescence intensity will slowly lose. Since this is a behavioral characteristic of green cell linker dye rather than red cell linker dye, PKH67 will have similar properties. The correlation between the in vitro cell membrane retention of non-dividing cells and the in vivo fluorescence half-life reveals that the in vivo fluorescence half-life of PKH67 is 10-12 days. Other green cell linker dyes with similar half-lives have been used to monitor the transport of lymphocytes and macrophages in the body within one to two months. The results indicate that PKH67 can also be used for medium-term in vivo tracking studies.The dye can stably bind to the lipid region of the cell membrane and emit fluorescence, and is mainly used for cell labeling in vitro, cell proliferation research in vitro, and cell tracing research in vivo and in vitro. The fluorescence half-life of PKH67 in vivo is 10-12 days. Compared with PKH-67, PKH-26 has a longer half-life, and the half-life of PKH26 labeled on rabbit red blood cells is more than 100 days. Especially suitable for in vitro proliferation research and long-term in vivo cell tracking research. After PKH67 labels the cells, flow cytometry is usually used for cell proliferation detection.Kit components0.1ml kits: P266290A-0.1ml P266290B-10ml1ml kits: P266290A-1ml P266290B-60mlDyes with A suffix and diluents with B suffix are used togetherPKH67 labeled cells show green fluorescence, the fluorescence wavelength: λex=490 nm, λem=502 nm.Storage conditions: -20℃ protected from light, valid for 1 yearPrecautions●Staining concentration varies according to the type of cell and the number of cells in each well.● The prepared PKH67 mother liquor is very easy to dissolve. It is recommended to store in aliquots and freeze-dry at ≦-20℃.● PKH67 working solution should be prepared for immediate use, and cannot be prepared in advance, because PKH67 will decompose due to the absorption of water and affect the dyeing effect.● PKH67 is easily decomposed and will deteriorate quickly in the water solution. Please avoid contact with water during use of mother liquor. The working fluid is in contact with the water during the process of labeling the cells within the permitted time range.● PKH67 fluorescent dye is a DMSO solution. It will solidify and stick to the bottom, wall or cap of the tube at a lower temperature such as 4℃ and ice bath. After being taken out of the refrigerator, it will return to room temperature and become After the liquid is in the state, remove the cap from the bottom of the tube. It can be used after it has completely melted in a 37°C water bath.● The number of generations or time that can be traced after different cell types are marked is quite different. Please make a test based on the actual situation or reference documents.Instructions1. Staining solution preparation:(1) Take out the PKH67 reagent from the refrigerator, let it stand for a few minutes to room temperature, or after a 37°C water bath, leave the tube containing PKH67, and be sure to leave the tube for a few minutes before opening the lid to allow the reagent to fully fall into the tube The lid can only be opened after the bottom.(2) According to the number of cell samples to be tested, dilute the probe 10 times with the diluent, and then use a suitable solution (such as non-clear medium, HBSS or PBS) to dilute the PKH67 mother liquor 25 times to prepare a stain Work fluid. The best working solution concentration should be adjusted according to different cells and your own experimental system. Generally, the cells can be diluted 250 times according to the final concentration of the mother liquor in the kit. Some cells may need to increase the concentration appropriately.2. Cell staining(1) Resuspend the prepared cells to be tested in 100µl of staining solution to a cell concentration of about 107/ml. You can also perform in-situ staining, as long as the staining solution is enough to cover the cells.(2) Culture the cells at 2～8℃ for 15～30 minutes. The best culture time is different for different cells.It is recommended to incubate the labeled cells in the staining solution at 37°C for 5 minutes, and then at 4°C for 15 minutes.Low-temperature incubation can reduce the endocytosis of the dye by the cells, help the dye to label the plasma membrane, and reduce the possibility of the dye localizing to cytoplasmic vesicles.(3) After separation, remove the supernatant, collect the cells, wash the cells 1-2 times with PBS or non-clear medium, and finally add PBS or non-clear medium to resuspend the cells.(4) Take 500µl of cell suspension and test with flow cytometer. Ex/Em=490/502nm.(5) Subsequently, the cells can be cultured according to the normal culture method.(6) The labeling effect can be directly observed under a fluorescence microscope, or the cell proliferation can be detected by a flow cytometer after an appropriate period of culture, or used for cell fluorescence traces for other specific experimental purposes... 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 | Inquire |