| Description | Product introduction：Used to isolate lymphocytes from human organsMatters needing attention：1. samples, reagents and experimental environment in the whole process shall be carried out at 20 ± 2 ℃. In order to obtain the best experimental results, it is best to carry out the Product introduction：Used to isolate lymphocytes from human organsMatters needing attention：1. samples, reagents and experimental environment in the whole process shall be carried out at 20 ± 2 ℃. In order to obtain the best experimental results, it is best to carry out the experiment within 2 h of sampling. The longer the sample is stored, the worse the cell separation effect is. The separation effect is even worse after the sample is placed for more than 6 h, or even cannot achieve the purpose of separation. 2. in this experiment, it is better not to use plastic products with high polymerization materials (such as polystyrene), but use non-static, low static ionization heart tubes and glass products without alkali treatment, because the electrostatic effect will lead to cell adhesion, and the surface of alkali treated glass will become rough, which will affect the effect of cell separation. 3. aspirating too many lymphocyte layers and separation liquid layers will cause the granulocytes at the junction of separation liquid to be aspirated, thus increasing the number of mixed granulocytes. 4. when the amount of separating solution is greater than that of tissue single cell suspension sample, the separation effect is better.Scope of application：Lymphocyte isolation... Read More | 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-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：555/565 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 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 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 fluidReaction componentsTaking the sample size of 10 holes as an example1×Click-iT EdU Reaction buffer855 µLCuSO4 (Component D)40 µLYF® 488/555/594/647A Azide(Component B)5 µL1×Click-iT EdU Buffer additives100 µLTotal volume1 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 fluidReaction componentsVolume of liquid required for a single reaction1×Click-iT EdU Reaction buffer875 µLCuSO4 (Component D)20 µLYF® 488/555/594/647A Azide(Component B)5 µL1×Click-iT EdU Buffer additives100 µLTotal volume1 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 | Inquire | 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 | Component Description T665563Component50 TStorageApplicationT665563AVNTR3820 1 mL-20℃. Avoid freeze/thaw cycle.High resolution 3-lite VNTR detectionT665563BVNTR41201 mL-20℃. Avoid freeze/thaw cycle.High resolution 3-lite VNTR detectionT665563CVNTR32321 mL-20℃. Avoid freeze/thaw Component Description T665563Component50 TStorageApplicationT665563AVNTR3820 1 mL-20℃. Avoid freeze/thaw cycle.High resolution 3-lite VNTR detectionT665563BVNTR41201 mL-20℃. Avoid freeze/thaw cycle.High resolution 3-lite VNTR detectionT665563CVNTR32321 mL-20℃. Avoid freeze/thaw cycle.High resolution 3-lite VNTR detectionT665563DMarkerⅠ300 µL-20℃. Avoid freeze/thaw cycle.DNA Molecular Weight Standard IT665563EMarkerⅡ250 µL-20℃. Avoid freeze/thaw cycle.DNA Molecular Weight Standard IIProduct IntroductionThis kit is a genotyping product for human Mycobacterium tuberculosis based on the latest research progress in molecular epidemiology1) and optimized by process. It utilizes variable-number tandem repeats (VNTR) polymorphisms in the Mycobacterium tuberculosis genome for genotyping to differentiate clinical strains, and is a powerful tool for studying the molecular epidemiology of Mycobacterium tuberculosis and monitoring the status of tuberculosis transmission. Compared with other existing Mycobacterium tuberculosis VNTR typing systems based on the VNTR principle, this typing system has a stronger ability to discriminate strains prevalent in China1,2,3), and is therefore particularly suitable for the needs of Chinese users.By carefully optimizing the primer sequences of each PCR reaction and the composition of the premixed reaction solution, this product has a strong anti-interference power. Compared with the user's own reagents, this product significantly improves the signal intensity of specific bands and reduces the appearance of non-specific bands when using crude templates (boiling bacterial solution), which makes the experimental operation easier and quicker, and at the same time, improves the success rate of the test. The premixed reaction solution is chemically stable and can effectively withstand repeated freezing and thawing (10 times) and a longer period of time (one week) at room temperature, which is better adapted to the user's need for flexibility in the detection work.This kit is a companion product to the TB Genotyping Kit VNTR-9. For samples identified as clustered or identical strains by the VNTR-9 kit, this product can be used for finer further typing identification if necessary. The three high-resolution detection sites VNTR3820, VNTR4120 and VNTR3232 in this product can be used in combination with the nine detection sites in the VNTR-9 to increase the resolution index (Hunter-Gaston index (HGI) to 0.9931).References1) Luo T et al. Development of a hierarchical variable-number tandem repeat typing scheme for Mycobacterium tuberculosis in China. PLoS One. 2014 Feb 25. 9(2)2)Sun G et al. Discriminatory potential of a novel set of Variable Number of Tandem Repeats for genotyping Mycobacterium marinum. Vet Microbiol. 2011 Aug Vet Microbiol. 2011 Aug 26;152(1-2)3) Zhang L et al. Highly polymorphic variable-number tandem repeats loci for differentiating Beijing genotype strains of Mycobacterium tuberculosis in Shanghai, China. FEMS Microbiol Lett. 2008 May;282(1):22-31.matters needing attention1.This product is a companion to the TB genotyping kit VNTR-9. The strains to be tested should be tested by VNTR-9 typing test first, and then use this product for testing. And the results of this product should be integrated and analyzed with the results of VNTR-9.2.To avoid contamination, it is recommended that the preparation of the organisms be done within a different location than the preparation of the PCR Mix and that different pipettes be used.3.Care should be taken at all stages of sample DNA collection, extraction and amplification to ensure proper labeling and to prevent cross-contamination between different samples.4.Commonly used reagents and consumables need to be autoclaved before experimentation.5.Each tube of PCR Mix contains different primers and cannot be mixed. It can be dispensed into different amounts at once according to the experimental needs to avoid repeated freezing and thawing.6.To avoid splashing the reaction solution when opening the reaction tube, centrifuge briefly before opening the cap and collect the liquid at the bottom of the tube. In case of accidental splashing on gloves or table, change gloves immediately and wipe the table with 75% alcohol or dilute acid.7.Be careful not to cross-contaminate the PCR Mix when aspirating, and it is recommended that the pipette tip be wiped with 75% alcohol 2 times before taking Mix each time.8.Pre-experiment preparation: 1×TE buffer (PH=8.0), 0.5×TBE buffer, agarose, ethidium bromide (EB), normal PCR instrument, DNA electrophoresis equipment and gel imager, 0.2 ml PCR reaction tubes, octuplex or 96-well PCR tubes, pipettes of different sizes: 0.5-10 µl and 20-200 µl.Operation steps1. DNA template preparation:1.1. scrape a small amount (1-2 inoculation loops) of sample from solid medium, resuspend in 100ul TE and inactivate at 80°C for 30 minutes.1.2. The inactivated strain was taken out of the P3 laboratory as follows:Boil at 100°C for 10 minutes (be careful to avoid bursting the cap of the EP tube during boiling to avoid letting water into the tube), place immediately on ice for 2 minutes, centrifuge at 12,000 rpm (~13,400 × g) for 10 minutes, take the supernatant and place in another sterile EP tube, label it, and store at -20°C.2. Testing procedures:2.1. Remove the TB Genotyping Kit HV-3, allow the liquid to equilibrate to room temperature, mix by shaking slightly 3-4 times, and then centrifuge at 12,000 rpm (~13,400 x g) for 5 seconds to allow the capped liquid to fall back into the tube.2.2.Three-locus VNTR typing: strains with identical results at 12 loci need to be further VNTR typed, i.e., the following four loci are added for comparison.1）PCR amplification: the reaction system was 20 µl. 19 µl of PCR Mix of VNTR3820, VNTR4120, and VNTR3232 were added to each PCR tube, 1 µl of DNA template was added, and mixed well.2）Amplification conditions:3) Gel preparation and electrophoresis:a: Notes:Important! Positive (H37Rv strain DNA) and negative controls (deionized water) need to be set up for each experiment.Key! This experiment is based on agarose gel electrophoresis to interpret the genotype of VNTR locus, therefore, in order to make the results accurate, it is necessary to follow the unified standard operation in this step of electrophoresis, and the following points should be noted:a-1: The comb used for glue making is 18 holes.a-2: The two wells on the left and right sides of the gel were discarded due to the tendency to distort the bands during electrophoresis, affecting the interpretation of the results, or a negative control was spotted in one of the wells. The remaining 16 wells were divided into 12 samples, 3 DNA Markers and 1 positive control. The order of spotting was "1, 2, M, 3, 4, 5, 6, M, 7, 8, 9, 10, M, 11, 12, H37Rv", the numbers represent samples, and M represents DNA Marker.a-3: When PCR amplification products are subjected to the first electrophoresis and Marker I is used, the gel concentration is 1%, the voltage is 150 V, and the time is 100-120 min.a-4: If the amplification product fragment is too large (>1000bp) and needs to be electrophoresed again and Marker II is used, the gel concentration is 0.8%, the voltage is 150V and the time is 150 minutes.b: Gluing as well as the electrophoresis process:PCR amplification products were electrophoresed using a 1% agarose gel.To prepare 1% agarose gel, 12×12 cm gel tray was used to make the gel, each gel was 80 ml.b-1: Weigh 0.8g of agarose, add 80ml of 0.5×TBE, weigh it on the balance and put it into the microwave oven, heat it on high for 2-3 minutes to make the agarose dissolve completely, shake it well, and observe it as a homogeneous and transparent solution without particles, then weigh it again on the balance and make up the appropriate amount of double-distilled water to keep the concentration of the gum unaffected.b-2: When the melted gel was cooled to about 55°C add 4 µl of ethidium bromide (10ug/ml) and gently swirl to mix well. The gel was made with an 18-tooth comb and the warm gel was poured into a 12 × 12 cm gel tray.b-3: Allow the gel to completely set (40 minutes at room temperature), carefully pull out the comb, remove the tray, and place it in the electrophoresis tank. Add 0.5× TBE buffer to the electrophoresis tank, not exceeding the gel surface by 1-2mm.b-4: Sample electrophoresis: add 12 samples to each gel (the topmost wells are not sampled), add 3-5µl PCR products to each well, and at the same time add three 5µl DNA MarkerⅠ to each gel. The voltage is 150V and the electrophoresis time is 100-120 minutes. This step is the key to the accuracy of the final readings of each point, and needs to be operated uniformly according to this standard.b-5: Some loci have amplification products greater than 1000bp in clinical strains, and these amplification products were then electrophoresed using 0.8% agarose gel, with DNA Marker II added as a control for the band size, voltage 150V, electrophoresis time 150 minutes.4) Results display:5) Analysis of results:a. If the genotypes of the three highly variable loci are also the same in different strains, they can be identified as clustered strains;b. If the high variant readings are highly similar, i.e., only 1-2 high variant sites are different, they need to be combined with epidemiologic data to identify if they are clustered strains;c. If all 3 high variant loci are genotypically discordant, identify as a single strain.Appendix 1: Rules for reading VNTR lociAppendix 2: VNTR locus repeat unit readout table... Read More |