| Description | Inquire | B669951 Component 50T Storage B669951A Buffer ATL 15 mL RT B669951B Buffer AL 15 mL RT B669951C Buffer AW1 (concentrate) 13 mL RT B669951D Buffer AW2 (concentrate) 15 mL RT B669951E Buffer EB 15 mL RT B669951F Proteinase K 1.25 mL RT B669951G Spin Columns DM with Collection Tubes 50 sets B669951 Component 50T Storage B669951A Buffer ATL 15 mL RT B669951B Buffer AL 15 mL RT B669951C Buffer AW1 (concentrate) 13 mL RT B669951D Buffer AW2 (concentrate) 15 mL RT B669951E Buffer EB 15 mL RT B669951F Proteinase K 1.25 mL RT B669951G Spin Columns DM with Collection Tubes 50 sets RTProductsThis kit is suitable for extracting high purity total DNA from Gram-negative and Gram-positive bacteria. 106-108 cells can be processed at a time, and up to 20 µg of total DNA can be obtained within one hour without the need for toxic solvents such as phenol or chloroform, and without the need for ethanol precipitation. The optimized buffer system enables the DNA in the lysate to be efficiently and specifically bound to the silica matrix centrifugal adsorption column, while other contaminants can flow through the membrane, and the inhibitors of PCR and other enzymatic reactions can be effectively removed through a two-step washing step, and finally washed off with low-salt buffer or water, so that high-purity DNA can be obtained.The purified DNA can be used for downstream experiments such as digestion, PCR, Real-Time PCR, library construction, Southern Blot and molecular labeling, molecular labeling and other downstream experiments. Self-contained reagents: anhydrous ethanol; Enzymatic Lysis Buffer is required for extraction of Gram-positive bacteria.Enzymatic Lysis Buffer was prepared by 20 mM Tris, pH 8.0; 2 mM Na2-EDTA, pH 8.0; and 1.2% Triton X-100. 121°C sterilization for 20 minutes, and the appropriate amount of Lysozyme was added at a final concentration of 20 mg/ml. Pre-experiment Preparation and Important Notes1. Add 1.25ml 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, and avoid repeated freezing and thawing to avoid affecting its activity.2. Repeated freezing and thawing of the sample should be avoided, as this may result in smaller DNA fragments and a decrease in the amount of extracted DNA.3. If extracting genomes from bacterial cultures with high accumulation of secondary metabolites or thick cell walls, it is recommended that samples be collected early in the logarithmic phase.4. Anhydrous ethanol should be added to Buffer GW1 and Buffer GW2 according to the instructions on the label of the reagent bottle before first use.5. Before use, please check Buffer GTL and Buffer GL for crystallization or precipitation. If crystallization or precipitation occurs, please re-dissolve Buffer GL and Buffer GTL in a 56℃ water bath.6. If the downstream experiments are sensitive to RNA contamination, 4µl of DNase-Free RNase A (100mg/ml) can be added before adding Buffer GL. RNase A is not provided in this kit.If the extracted samples are Gram-positive bacteria, customers need to prepare their own Enzymatic Lysis Buffer to treat the bacteria, which requires the use of Lysozyme (lysozyme) at a concentration of 20 mg/ml, which is not provided in this kit.Procedurei Extraction of genomic DNA from Gram-negative bacteria1. Take 1-5 ml of bacterial culture (106-108 cells, maximum 2×109 cells) and put it into a centrifuge tube (provided), centrifuge it at 12,000 rpm (~13,400×g) for 1 minute, and aspirate the supernatant as much as possible.2. Add 180 µl Buffer GTL to the precipitate and shake to resuspend the bacteria.3. Add 20 µl of Proteinase K, vortex and mix well, incubate at 56°C until the solution becomes clear, and invert or shake the centrifuge tube at intervals during the incubation to disperse the sample.Note: If RNA removal is required, add 4 µl of RNase A solution at a concentration of 100 mg/ml after the above steps are completed, shake to mix, and leave for 5-10 minutes at room temperature.4. Add 200µl Buffer GL and mix well with vortexing and shaking. Add 200µl of anhydrous ethanol and mix well with vortexing and shaking.Centrifuge briefly so that the solution on the walls of the tube collects at the bottom.Note: 1) If multiple samples are manipulated together, Buffer GL and anhydrous ethanol can be mixed in equal proportions and then added together, shaking to mix.2) The addition of Buffer GL and anhydrous ethanol may produce a white precipitate that will not affect subsequent experiments.5. Add all of the solution obtained in step 4 (including the precipitate formed) to the Spin Columns DM in the collection tube, or if the solution cannot be added all at once, transfer it several times. centrifuge at 12,000 rpm for 1 minute, discard the waste solution, and return the column to the collection tube.6. Add 500 µl of Buffer GW1 to the adsorption 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 return the adsorption column to the collection tube.7. Add 500 µl of Buffer GW2 to the adsorption 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 adsorption column back into the collection tube.Note: Step 7 can be repeated if further DNA purity is required.8. Centrifuge at 12,000 rpm for 2 minutes and pour off the waste liquid in the collection tube. Leave the adsorbent column at room temperature for several minutes to 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.).9. Place the adsorption column in a new centrifuge tube, add 50-200 µl Buffer GE to the middle part of the adsorption column overhanging the center of the adsorption column, leave it at room temperature for 2-5 minutes, centrifuge it at 12,000 rpm for 1 minute, collect the DNA solution, and store the DNA at -20 ℃. note: 1) If the downstream experiments are sensitive to the pH or EDTA, the elution can be done with sterilized water. The pH of the elution solution has a great influence on the elution efficiency. If water is used as the elution solution it should be ensured that its pH is 7.0-8.5 (the pH of water can be adjusted to this range with NaOH), and the elution efficiency is not high when the pH is lower than 7.0.2) Incubation at room temperature for 5 minutes prior to centrifugation increases yield.3) Re-elution with an additional 50-200 µl Buffer GE or sterilized water can increase the yield.4) If the final concentration of DNA is to be increased, the DNA eluate obtained in step 9 can be re-spiked onto the adsorbent membrane and step 9 repeated; if the elution volume is less than 200 µl, the final concentration of DNA can be increased, but the total yield may be reduced. If the amount of DNA is less than 1 µg, elution with 50 µl Buffer GE or sterilized water is recommended.(5) 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℃.i. Extraction of genomic DNA from Gram-positive bacteria1. Take 1-5 ml of bacterial culture (106-108 cells, maximum 2×109 cells) and put it into a centrifuge tube (provided), centrifuge it at 12,000 rpm (~13,400×g) for 1 minute, and aspirate the supernatant as much as possible.2. Add 180µl Enzymatic Lysis Buffer (self-provided) to resuspend the bacteria.Enzymatic Lysis Buffer is prepared as described in the Self-Prepared Reagents section in the front of the manual.3. Incubate at 37°C for 30 minutes.4. Add 20µl Proteinase K and mix well. Add 200µl of Buffer GL and mix well with vortexing and shaking.Note: Do not add Proteinase K directly to Buffer GL.Incubate at 5.56°C for 30 minutes.Note: 1) If desired, incubation at 95°C for 15 minutes will inactivate the pathogen, but 95°C incubation will cause some DNA degradation.(2) If RNA removal is required, add 4µl of RNase A solution at a concentration of 100mg/ml after the above steps are completed, shake and mix well, and leave for 5-10 minutes at room temperature.6. Add 200µl of anhydrous ethanol and mix well with vortex shaking.Note: The addition of anhydrous ethanol may produce a white precipitate that will not affect subsequent experiments.7. Add all of the solution obtained in step 6 (including the precipitate formed) to the Spin Columns DM that have been loaded into the collection tube, and if the solution cannot be added all at once, it can be transferred in several times. centrifuge at 12,000 rpm for 1 minute, pour off the waste liquid from the collection tube, and put the column back into the collection tube.8. Add 500 µl of Buffer GW1 to the adsorption 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 adsorption column back into the collection tube.9. Add 500 µl Buffer GW2 to the adsorption column (check that anhydrous ethanol has been added before use), centrifuge the column at 12,000 rpm for 1 minute, pour off the waste liquid in the collection tube, and put the column back into the collection tube.Note: Step 9 can be repeated if further DNA purity is required.10. 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; ethanol residue can interfere with subsequent enzymatic reactions (digestion, PCR, etc.).11. Place the adsorption column in a new centrifuge tube (self-provided), add 50-200 µl of Buffer GE to the center of the adsorption column overhanging the center of the adsorption column, let it stand 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 or EDTA, you can use sterilized water for elution. The pH of the eluent has a great influence on the elution efficiency, if water is used as the eluent should ensure that its pH is 7.0-8.5 (you can use NaOH to adjust the pH of the water to this range), and the elution efficiency is not high when the pH is lower than 7.0.2) Incubation at room temperature for 5 minutes prior to centrifugation increases yield.3) Re-elution with an additional 50-200 µl Buffer GE or sterilized water can increase the yield.4) If the final concentration of DNA is to be increased, the DNA eluate obtained in step 11 can be re-spiked onto the adsorbent membrane and step 11 repeated; if the elution volume is less than 200 µl, the final concentration of DNA can be increased, but the total yield may be reduced. If the amount of DNA is less than 1 µg, elution with 50 µl Buffer GE or sterilized water is recommended.(5) 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 | DescriptionMaterials included in the kit are designed to be used with the Hy-Energy′s PCTPro-2000 System. They also can be used for demonstration purposes and as standards during the development of novel hydrogen storage and battery materials | S665948 Component 1 mL 5 mL Storage S665948A 2×SYBR qPCR Master Mix 1 mL 5×1 mL -20℃. Avoid freeze/ Thaw cycle. S665948B qPCR Primer Mix 100 µL 5×100 µL -20℃. Avoid freeze/ Thaw cycle. S665948C DNA Standard 1 100 µL 5×100 µL -20℃. Avoid S665948 Component 1 mL 5 mL Storage S665948A 2×SYBR qPCR Master Mix 1 mL 5×1 mL -20℃. Avoid freeze/ Thaw cycle. S665948B qPCR Primer Mix 100 µL 5×100 µL -20℃. Avoid freeze/ Thaw cycle. S665948C DNA Standard 1 100 µL 5×100 µL -20℃. Avoid freeze/ Thaw cycle. S665948D DNA Standard 2 100 µL 5×100 µL -20℃. Avoid freeze/ Thaw cycle. S665948E DNA Standard 3 100 µL 5×100 µL -20℃. Avoid freeze/ Thaw cycle. S665948F DNA Standard 4 100 µL 5×100 µL -20℃. Avoid freeze/ Thaw cycle. S665948G DNA Standard 5 100 µL 5×100 µL -20℃. Avoid freeze/ Thaw cycle. S665948H 50×High ROX 40 µL 200 µL -20℃. Avoid freeze/ Thaw cycle.Product IntroductionThis product is used for real-time fluorescence quantitative PCR (qPCR) using the product after NGS library construction by dye method (SYBR Green I). The kit provides the reaction mixture, DNA primer mixture, and standards required for the qPCR process, and the reagent system is complete, easy and convenient to operate. The kit uses a new chemically modified high-efficiency hot-start polymerase, the activation of the enzyme needs to be incubated at 95 ℃ for 10 min. the product is highly specific, high amplification efficiency, and able to quickly and accurately quantify the concentration of the constructed library. It is suitable for fluorescent quantitative PCR instruments that do not require ROX as a calibration dye, such as Roche LightCycler 480, Roche LightCyler 96, Bio-radiCyleriQ, iQ5, CFX96.ROX dye is used to correct the fluorescence signal error generated between wells of a quantitative PCR instrument, and is generally used in Real Time PCR amplifiers from ABI, Stratagene, and other companies. The excitation optics vary from instrument to instrument, so the concentration of ROX dye must be matched to the corresponding fluorescence quantitative PCR instrument.Instruments that do not require ROX calibration: Roche LightCycler 480, Roche LightCyler 96, Bio-rad iCyler iQ, iQ5, CFX96, etc.Instruments requiring Low ROX calibration: ABI Prism7500/7500 Fast, QuantStudio®3 System, QuantStudio®5 System, QuantStudio®6 Flex System, QuantStudio®7 Flex System, ViiA 7 System, Stratagene Mx3000/Mx3005P, Corbett Rotor Gene 3000, and others.Instruments requiring High ROX calibration: ABI Prism7000/7300/7700/7900, Eppendorf, ABI Step One/Step One Plus, etc.Note: High Rox and Low Rox are formulated as described in Use 2.Scope of applicationThis product is designed for absolute quantification of the concentration of Illumina platform second-generation sequencing libraries. The end of the library contains Illumin P5 and P7 chip binding sequences, the length of which does not exceed 1kb, and the concentration of which is not less than 0.002pM can be used to perform quantitative experiments with this product. The qPCR Primer Mix provided in the kit contains the following two primer sequences:Primer 1:5'-AAT GAT ACG GCG ACC ACC GA-3' Primer 2: 5'-CAA GCA GAA GAC GGC ATA CGA-3'The primer sequence can be used in advance to confirm whether the library can be amplified by that primer pair.UsageAmplification template preparationThe library samples to be detected were diluted with TE (10 mM Tris-Cl, pH 8.0, 1 mM EDTA), and the concentration after dilution was as close as possible to the range of 0.01-20 pM. 4°C on ice was set aside.qPCR reaction system preparationThe desired cryopreservation reagent is pre-melted completely and mixed by inverting several times before preparation, then centrifuged briefly and set aside.The base reaction system for 20 µl was as follows:Reagent20 µl Reaction system2×SYBR qPCR Master Mix10 µlqPCR Primer Mix 10.8 µlTemplate4 µlddH₂O5.2 µlDescription: High Rox model: add 1 µl High Rox per 50 µl of reaction system;Low Rox model: 1 µl High Rox per 500 µl of reaction system.Prepare a sufficient amount of reaction system mixture according to the need, mix well and add to the reaction wells in a volume of 16 µl per well, add the same volume of TE to the blank control, and then add the prepared standards and diluted samples to the corresponding reaction wells in a volume of 4 µl/well. It is recommended to use 20 µl reaction system, if you need to carry out a smaller system reaction, the system components can be reduced in equal proportion.qPCR reaction programThe annealing temperature should be 60-64°C as a reference for the setting range, and the annealing temperature can be increased when a non-specific reaction occurs.If the average length of the library is greater than 700bp, the annealing/extension time should be increased appropriately.data analysisStandard curve productionThe standard curve was plotted using Ct values in the valid range. The standard curve correlation coefficient R2 should not be less than 0.99 and the slope should lie between -3.1 and -3.6. If the standard curve parameters are not reasonable, it is recommended to repeat the experiment.DNA Standard NameDNA Standard ConcentrationDNA Standard 120 pMDNA Standard 22 pMDNA Standard 30.2 pMDNA Standard 40.02 pMDNA Standard 50.002 pMLibrary Concentration CalculationsThe difference in Ct between the three replicate wells of the experiment should be no more than 0.2, otherwise the invalid data should be deleted or the experiment should be repeated. Do not use the Ct outside the valid Ct range of the standard curve to calculate the concentration of the diluted libraries. Please refer to the data processing Excel of this product for the specific library concentration calculation method.matters needing attentionThese instructions should be read in detail before testing. It should be carried out by personnel with specialized experience or qualified by training.Mix gently by turning up and down, avoid foaming as much as possible, and centrifuge for a short time before use.Avoid repeated freezing and thawing of this product; repeated freezing and thawing may degrade product performance.When preparing reaction solutions, use new or non-contaminated tips and centrifuge tubes to prevent contamination as much as possible... 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 |