| Description | Inquire | Cell proliferation detection is a basic experimental method to evaluate the health of cells, genotoxicity and the effect of antitumor drugs. The most accurate method to detect cell proliferation is the BrdU method. Edu detection kit is a revolutionary breakthrough of BrdU method. Edu (5-ethynyl-2 '-Cell proliferation detection is a basic experimental method to evaluate the health of cells, genotoxicity and the effect of antitumor drugs. The most accurate method to detect cell proliferation is the BrdU method. Edu detection kit is a revolutionary breakthrough of BrdU method. Edu (5-ethynyl-2 '- deoxyuridine) is a pyrimidine analog that integrates into the DNA duplex during DNA synthesis. Edu detection is based on the "click" reaction. A copper catalyzed azide reacts covalently with alkynes to form covalent bonds. In this kit, edu contains alkynes, Aladdin ® 488 / 555/594/647a azide dyes contain azide compounds. The edu labeling proliferation of click method is rapid and effective, and easy to use. BrdU method requires DNA denaturation (such as acid denaturation, thermal denaturation or digestion with DNase) to expose BrdU, so as to facilitate BrdU antibody binding; The edu method only needs paraformaldehyde fixation and Triton X-100 penetration to make the detection reagent enter the cells, and only a small amount of azide dye is needed to label the integrated edu very effectively. This kit contains all components required for edu method detection, and can be used for proliferation detection of cultured cells in vitro. Component：Product parameters： 590/617 nm Instruction：Experimental materials (self provided). 10 mM PBS, pH 7.2-7.6. 4% paraformaldehyde fixing solution (in PBS)Propensive reagent (0.5% Triton X -100 in PBS). 2 mg/mL glycine solution (in ddH2O). 3% BSA in PBS, pH 7.2-7.6. 1% BSA in PBS, pH 7.2-7.6. ddH2O. 96/24/12/6 well culture plate or dishFluorescence microscopy detection method1. Cell cultureTake logarithmic growth stage cells and inoculate them into a 96 well plate with 4 × 103-1 × 105 cells per well (the number and density of cells can be adjusted according to cell size, growth rate, and specific requirements of experimental treatment), and culture until normal growth stage.2. Drug treatmentPerform various drug treatments according to experimental needs.3. EdU marking(1) Dilute EdU solution (component A) in a certain proportion with complete cell culture medium to an appropriate concentration, then add it to the cells and mix well; Set up a negative control group without EdU treatment.Note: The labeling concentration of EdU needs to be adjusted according to cell type, and it is recommended to explore with an initial concentration of 10 µ M. In the pre experiment, it is recommended to set an EdU concentration gradient, which can be referred to in Tables 2 and 3.(2) Incubate in a cell culture incubator for 2 hours.Note: The optimal incubation time is related to the cell cycle. Most tumor cell lines can use a 2-hour incubation time, as shown in Appendix 2. The concentration of EdU is related to incubation time,Short term incubation (<2 hours) should use high concentrations, such as 10-50 µ M; Long term incubation (>24 hours) should use low concentrations, such as 1-10 µ M; You can also refer to Appendix 3.4. Cell fixation and permeation promotionNote: For experiments that require cell surface antigen labeling, it can be considered to wash the cells twice with a 3% BSA washing solution after completing EdU incubation, before cell fixation and permeation promotion.(1) After incubation, remove the culture medium. Wash cells twice with 1X PBS for 5 minutes each time to remove EdU residues that have not been incorporated into DNA. Cells with weak adhesion can reduce cleaning intensity. Join 50 µ After incubating at room temperature for 20 minutes with 4% paraformaldehyde fixative, remove the fixative.(2) Add 50 to each hole µ L 2 mg/mL glycine solution, incubate at room temperature for 5 minutes, and neutralize the remaining fixed solution.(3) At a rate of 100 per hole µ Wash cells twice with 3% BSA.(4) Remove the washing solution and add 100 µ L 0.5% Triton X -100, incubate at room temperature for 10 minutes.5. EdU detectionNote: Each sample in this reference step uses 100 µ The working fluid of L can be adjusted by users according to their own sample situation.(1) Prepare 1 x Click iT EdU reaction buffer (component C): Dilute component C 10 times with ddH2O.(2) Configure 5 x Click iT EdU buffer additives (component E): add 300 µ Mix L of ddH2O into a 30 mg E component tube (final concentration of 100 mg/mL) until completely dissolved. After use, the remaining storage solution is stored at -20 ℃ and can be stored for one year. Once the solution turns brown, it indicates that the active ingredients have degraded and cannot be reused.Note: Different specifications of component E are dissolved in ddH2O according to this ratio, and prepared into a 5 x storage solution for future use.(3) Prepare 1 x Click iT EdU buffer additive: Dilute 5 x Click iT EdU buffer additive with ddH2O to 1 x, and the solution should be prepared and used immediately.(4) Prepare Click it working solution according to Table 1.Table 1 Click it working fluid Reaction components Taking the sample size of 10 holes as an example 1 x Click it EdU reaction buffer 855 µL CuSO4 (component D) 40 µL YF® 488/555/594/647A Azide(Component B) 5 µL 1 x Click it EdU buffer additive 100 µL Total volume 1 mL (5) Remove penetration enhancer, 100 per well µ Wash twice with 3% BSA washing solution of L.(6) Add 100 to each hole µ L Click iT working solution, evenly covering cells.(7) Incubate at room temperature in dark for 30 minutes.(8) Remove Click-iT working fluid and add 100 µ After washing cells twice with 3% BSA, remove the washing solution and add 100 µ L PBS keeps cells moist. If there are no other special requirements, photography analysis can be carried out.6. DNA re staining (optional)(1) Using 100 µ Wash the cells once with PBS and remove the washing solution.(2) Dilute Hoechst 33342 (component F) 2000 times with PBS.(3) Add 100 to each hole µ Incubate L 1 x Hoechst 33342 solution at room temperature in dark for 15-30 minutes.(4) Remove Hoechst 33342 solution and use 100 µ Wash cells twice with PBS.7. Imaging and analysisIt is recommended to take fluorescence microscopy photos immediately after staining is completed for observation; If conditions permit, please store in a dark and moist environment at 4 ° C for 3 days before taking photos. Flow cytometry detection method1. Cell cultureInoculate 1 × 105~3 × 106 cells per well into a 6-well plate.2. Drug treatmentPerform various drug treatments according to experimental needs.3. EdU labeled cells(1) Dilute EdU solution (component A) in a certain proportion with complete cell culture medium to an appropriate concentration, then add it to the cells and mix well; Set up a negative control group without EdU treatment.Note: The labeling concentration of EdU needs to be adjusted according to cell type, and it is recommended to explore with an initial concentration of 10 µ M. In the pre experiment, it is recommended to set an EdU concentration gradient, which can be referred to in Tables 2 and 3.(2) Incubate in a cell culture incubator for 2 hours. The time of EdU incubation of cells can be directly used as an indicator for measuring cell DNA synthesis, and the choice of time point and incubation time depend on the cell growth rate. Pulse labeled cells incubated with brief EdU can be used to study cell cycle dynamics.Note: The optimal incubation time is related to the cell cycle. Most tumor cell lines can use a 2-hour incubation time, as shown in Appendix 2. The concentration of EdU is related to the incubation time, and high concentrations, such as 10-50, should be used for short-term incubation (<2 hours) µ M; Long term incubation (>24 hours) should use low concentrations, such as 1-10 µ M; You can also refer to Appendix 3.4. Cell fixation and permeation promotionNote: For experiments that require cell surface antigen labeling, it can be considered to wash cells twice with 1% BSA after completing EdU incubation, before cell fixation and permeation promotion.(1) After incubation, collect cells, add 1 mL of PBS to each tube to clean the cells, centrifuge at 1000 rpm for 5 minutes, and discard the supernatant to remove EdU residue that has not been added to DNA.(2) Add 1 mL of 4% paraformaldehyde fixative to each tube to resuspend cells.(3) Incubate at room temperature for 20 minutes, centrifuge at 1000 rpm for 5 minutes, and discard the supernatant.(4) Add 1 mL of 2 mg/mL glycine to each tube and incubate for 5 minutes. Neutralize the remaining fixed solution, centrifuge at 1000 rpm for 5 minutes, and discard the supernatant. Add 1 mL of PBS to each tube for cleaning once, centrifuge at 1000 rpm for 5 minutes, and discard the supernatant.(5) Add 1mL of 0.5% Triton X-100 osmotic enhancer to each tube and resuspend cells. Incubate at room temperature for 10 minutes.5. EdU detectionNote: For 6-well plate samples, reference can be made to 1 mL of working solution per well. Users can adjust the dosage according to their own sample situation.(1) Prepare 1 x Click iT EdU reaction buffer: Dilute component C 10 times with ddH2O.(2) Prepare 5 x Click iT EdU buffer additives (component E): Add 300 µ L ddH2O to 30 mg of component E in a test tube (final concentration 100 mg/mL), mix well until completely dissolved. After use, the remaining storage solution is stored at -20 ℃ and can be stored for one year. Once the solution turns brown, it indicates that the active ingredients have degraded and cannot be reused.Note: Different specifications of component E are dissolved in ddH2O according to this ratio to form 5 x storage solution for future use.(3) Prepare 1 x Click iT EdU buffer additive: Dilute 5 x Click iT EdU buffer additive storage solution with ddH2O to 1 x, and the solution should be prepared and used immediately.(4) Prepare Click it working solution according to Table 2.Table 2 Click it working fluid Reaction components Volume of liquid required for a single reaction 1×Click-iT EdU reaction buffer 875 µL CuSO4 (component D) 20 µL YF® 488/555/594/647A Azide(Component B) 5 µL 1×Click-iT EdU buffer additive 100 µL Total volume 1 mL (5) Soak at 1000 rpm for 5 minutes, discard the supernatant, remove the enhancer, add 1mL of 1% BSA washing solution to each tube and wash twice. Soak at 1000 rpm for 5 minutes, discard the supernatant.(6) Add 1 mL of Click iT working solution to each tube and mix well.(7) Incubate at room temperature in dark for 30 minutes.(8) Soak at 1000 rpm for 5 minutes, discard the staining reaction solution, add 1% BSA to each tube to wash the cells twice, centrifuge at 1000 rpm for 5 minutes, discard the supernatant, and resuspend the cells again with 1 mL of 1% BSA (the volume of resuspend cells can be adjusted according to the number of cells), and detect with a flow cytometer.Note: If other biomarker tests are required, please refer to step 4.6. Intracellular antigen labeling (optional steps)(1) Add antibody working solution and mix well.(2) Under dark conditions, incubate antibodies at appropriate temperature and time.7. Flow detection and analysis:(1) It is recommended to conduct flow cytometry testing immediately after dyeing is completed; If conditions are limited, please store in a dark place at 4 ℃ for testing, but it should not exceed 3 days.(2) It is recommended to test the number of cells up to one million levels as much as possible. If the number of cells is small, the number of cells tested can be adjusted to 100000 levels starting from the experiment. For cases where the cell yield is too low (just to the level of ten thousand), it may not be conducive to making a flow chart. Therefore, the cleaning frequency in step 5 (8) can be appropriately reduced.Matters needing attention：1. please centrifuge the product to the bottom of the tube immediately before use, and then conduct subsequent experiments. 2. fluorescent dyes have quenching problems. Please try to avoid light during experimental operation to slow down fluorescence quenching. 3. click it edu buffer additive solution should be prepared and used immediately to ensure the best results. 4. for your safety and health, please wear experimental clothes and disposable gloves.Scope of application：Cell proliferation detection (cell imaging flow universal)... Read More | Product content: G665990Component200 TStorageG665990ABuffer PG100 mLRTG665990BBuffer PS60 mLRTG665990CBuffer PW (concentrate)50 mLRTG665990DBuffer EB30 mLRTG665990ESpin Columns DM with Collection Tubes200 EART Product Introduction:This kit uses a new silicon-based plasma membrane technology and Product content: G665990Component200 TStorageG665990ABuffer PG100 mLRTG665990BBuffer PS60 mLRTG665990CBuffer PW (concentrate)50 mLRTG665990DBuffer EB30 mLRTG665990ESpin Columns DM with Collection Tubes200 EART Product Introduction:This kit uses a new silicon-based plasma membrane technology and reagent formulation. Through the unique centrifugal adsorption column and the DNA washing elution step, 100 bp-10 kb DNA fragments can be recovered and purified from ordinary or low melting point agarose gel. The sol speed is fast and the recovery rate is high. The sol solution contains a pH indicator, which can be used to determine whether the sol recovery has reached the optimal state based on its color. Each adsorption column can adsorb up to 10 µ G DNA, while effectively removing impurities such as primers, enzymes, mineral oil, and agarose. The purified and recovered DNA has high purity and concentration, good integrity, and can be directly used for molecular biology experiments such as sequencing, linking and transformation, labeling, and in vitro transcription.Self prepared reagents: anhydrous ethanol, isopropanol.Preparation and important precautions before the experiment:1.Before the first use, anhydrous ethanol should be added to the Buffer PW according to the instructions on the reagent bottle label.2. Before use, please check the Buffer PG. If crystallization or precipitation occurs, it can be left in a 37 ℃ water bath for 3-5 minutes to restore clarity.3. It is best to use a new electrophoresis buffer during electrophoresis to avoid affecting the electrophoresis and recovery efficiency; The following experiment requires high requirements, please use TAE electrophoresis buffer as much as possible.4.When cutting glue, the UV irradiation time should be as short as possible to avoid damage to DNA.5. The recovery rate 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. Preheat the water bath to 50 ℃.7. Buffer PG contains a pH indicator. When the pH is ≤ 7.5, the color of the solution is yellow, and DNA can effectively bind to the membrane. When the pH is too high, the color of the solution turns orange red and purple, which needs to be adjusted.8. All centrifugation steps can be performed at room temperature.Operation steps:1. Cut the single purpose DNA strip from the agarose gel (try to cut the excess), put it into a clean centrifuge tube (self prepared), and weigh and calculate the weight of the gel (record the weight of the centrifuge tube in advance).Attention: If the volume of the adhesive block is too large, it can be cut into small pieces.2. Add one time of the volume of Buffer PG (if the gel weighs 100 mg, its volume can be regarded as 100 µ l. And so on.3.50 ℃ water bath and gently invert the centrifuge tube every 2-3 minutes until the sol turns yellow to ensure full dissolution of the gel block. If there are still unsolved glue blocks, you can add some more sol solution or continue to let it stand for a few minutes until the glue blocks are completely dissolved.Note: 1) After the gel is completely dissolved, the gel solution is yellow, and subsequent operations can be carried out; If the glue solution is orange red or purple, 10-30 can be added to the glue solution µ 3 M sodium acetate (pH 5.0), adjust the color of the solution to yellow before proceeding with subsequent operations.2) After the gel block is completely dissolved, it is best to lower the temperature of the gel solution to room temperature before loading the column. The adsorption column has a weaker ability to bind DNA at higher temperatures.4. (Optional step) When the recovered fragment is less than 300 bp, add 1/2 of the gel volume of isopropanol, and mix it upside down (if the gel weighs 100 mg, add 50 µ Isopropanol of L.5. 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.6. Add the solution obtained from steps 3 or 4 to the adsorption column that has been loaded into the collection tube, let it stand at room temperature for 2 minutes, centrifuge at 13000 rpm for 1 minute, 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 can be added in batches.7. Add 450 to the adsorption column µ LBuffer PW (please check if anhydrous ethanol has been added before use), centrifuge at 13000 rpm for 1 minute, discard the waste liquid in the collection tube, and place the adsorption column in the collection tube.Note: If purified DNA is used for salt sensitive experiments (such as flat end ligation or direct sequencing), it is recommended to add Buffer PW and let it stand for 2-5 minutes before centrifugation.8. Repeat step 7.9.13000 rpm for 1 minute and discard the waste liquid from the collection tube.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.).10. Place the adsorption column into a new 1.5 ml centrifuge tube (provided by oneself), and add 50 drops to the middle position of the adsorption membrane in the air µ L Buffer EB, leave at room temperature for 2 minutes. Centrifuge at 13000 rpm for 1 minute and collect DNA solution- Store DNA at 20 ℃.Attention:1) To improve the recovery of DNA, the solution obtained by centrifugation can be re dropped onto the adsorption column, left at room temperature for 2 minutes, and centrifuged at 13000 rpm for 1 minute.2) The elution volume should not be less than 30 µ l. A small volume will affect the recovery efficiency.3) When recovering DNA fragments larger than 10 kb, Buffer EB should be preheated in a 50 ℃ water bath to increase recovery efficiency.Note: This reagent kit is also suitable for the purification and recovery of PCR products. Add an equal volume of Buffer PG to the PCR reaction solution and mix thoroughly (for small fragments with a recovery of less than 150bp, the solution volume can be increased to three times to improve the recovery rate). Follow step 5 above for further operations... Read More | This reagent kit is for research purposes only. Purpose of use: This reagent kit is used to determine the content of lactose in serum, plasma, and related liquid samples.Experimental principle:This kit applies enzyme-linked immunosorbent assay to determine the level of lactose in the sample. This reagent kit is for research purposes only. Purpose of use: This reagent kit is used to determine the content of lactose in serum, plasma, and related liquid samples.Experimental principle:This kit applies enzyme-linked immunosorbent assay to determine the level of lactose in the sample. Purified lactose antibodies were coated on a microplate to produce solid-phase antibodies. Lactose was added to the microplate of the coated monoclonal antibody, along with HRP labeled lactose antigens, to compete for binding. After thorough washing, the substrate TMB was added for colorimetry. The depth of sample color is negatively correlated with the content of lactose in the sample. Measure the absorbance (OD value) at a wavelength of 450nm using an enzyme-linked immunosorbent assay (ELISA) reader, and calculate the content of lactose in the sample through a standard curve.Kit composition:130times concentrated washing solution20ml×1 bottle8.1Standard S1（80µg/L）0.5ml×1bottle2Enzyme-linked immunosorbent assay6ml×1 bottle8.2Standard S2（40µg/L）0.5ml×1bottle3Enzyme labeling coated plate96 holes x 1 pieces8.3Standard S3（20µg/L）0.5ml×1bottle4Color reagent A solution6ml×1 bottle8.4Standard S4（10µg/L）0.5ml×1bottle5Color developer B solution6ml×1 bottle8.5Standard S5（5µg/L）0.5ml×1bottle6Stop solution6ml×1 bottle9Instructions1 copy7Sample Diluent6ml×1 bottle10Microplate Sealers2 sheetsSpecimen requirements:1. Specimen processing:(1) After collecting the water sample, it is repeatedly freeze-thawed three times at -20 ℃, and then filtered through glass fiber for future reference(2) The tissue samples should be extracted using butanol: methanol: water (5:25:70 V: V: V), or extracted according to relevant literature. The experiment should be conducted as soon as possible after extraction. If the experiment cannot be conducted immediately, the specimen can be stored at -20 ℃ for future reference2. Samples containing NaN3 cannot be detected as NaN3 inhibits the activity of horseradish peroxidase (HRP).Operation steps:1. Sample addition: Set up standard wells, blank wells (blank control wells do not include samples and enzyme-linked immunosorbent assay reagents, the other steps are the same), and sample wells to be tested. Add 50 microliters to the standard well on the enzyme-linked immunosorbent assay (ELISA) plate, and first add 40 diluents to the sample well to be tested µ l. Then add 10 more samples to be tested µ L (The final dilution of the sample is 5 times). Add the sample to the bottom of the enzyme-linked immunosorbent assay (ELISA) plate well, avoiding touching the well wall as much as possible. Gently shake and mix well.2. Enzyme addition: Add 50 enzyme labeled reagents to each well µ l. Excluding blank holes.3. Warm incubation: Seal the plate with a sealing film and incubate at 37 ℃ for 60 minutes.4. Solution preparation: Dilute 30 times the concentrated washing solution with distilled water and set aside for later use5. Washing: Carefully remove the sealing film, discard the liquid, shake dry, fill each well with washing solution, let it stand for 30 seconds, then discard. Repeat this process 5 times and pat dry.6. Color development: Add color development agent A50 to each well first µ l. Add color developer B50 again µ l. Gently shake and mix well, and develop color at 37 ℃ in the dark for 15 minutes7. Termination: Add 50% termination fluid to each hole µ l. Terminate the reaction (at this point, the blue color immediately turns yellow).8. Measurement: Zero the blank hole and sequentially measure the absorbance (OD value) of each hole at a wavelength of 450nm. The measurement should be conducted within 15 minutes after adding the termination solution.Calculation:Draw a standard curve on a coordinate paper with the concentration of the standard substance as the x-axis and the OD value as the y-axis. Based on the OD value of the sample, determine the corresponding concentration from the standard curve; Multiply it by the dilution factor; Alternatively, a linear regression equation can be used to calculate the standard curve using the concentration and OD value of the standard substance. The OD value of the sample can be substituted into the equation to calculate the sample concentration, which is then multiplied by the dilution factor to obtain the actual concentration of the sample.Notes:1. The kit should be balanced at room temperature for 15-30 minutes before use when taken out from the cold storage environment. If the enzyme coated plate is not used up after opening, the Flat noodles should be stored in a sealed bag.2. Concentrated detergent may precipitate crystals. When diluted, it can be heated in a water bath to aid in dissolution. Washing does not affect the results.3. A sampler should be used for each step of sample addition, and its accuracy should be regularly calibrated to avoid experimental errors. It is best to control the sample addition time within 5 minutes. If there are a large number of specimens, it is recommended to use a firing gun for sample addition.4. Please make a standard curve at the same time as each measurement, preferably with a re hole. If the content of the substance to be tested in the sample is too high (the OD value of the sample is greater than the OD value of the first well of the standard well), please dilute the sample diluent by a certain multiple (n times) before measurement. When calculating, please multiply the total dilution multiple (x n x 5).5. The sealing film is only for one-time use to avoid cross contamination.6. Please store the substrate in dark.7. Strictly follow the instructions and determine the test results based on the reading of the enzyme-linked immunosorbent assay (ELISA) reader8. All samples, washing liquids, and various waste should be treated as infectious substances.9. The components of this reagent with different batch numbers shall not be mixed.Detection range:two µ G/L-90 µ G/L... 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 |