| Description | Inquire | Products content Box 1: Circularization reagentC666001Component16 TStorageC666001ASplint Oligo20 µL-20℃.Avoid freeze/thaw cycle. C666001B5×Splint Buffer T4250 µL-20℃.Avoid freeze/thaw cycle. C666001CDNA Ligase50 µL-20℃.Avoid freeze/thaw cycle. C666001DDigestion Products content Box 1: Circularization reagentC666001Component16 TStorageC666001ASplint Oligo20 µL-20℃.Avoid freeze/thaw cycle. C666001B5×Splint Buffer T4250 µL-20℃.Avoid freeze/thaw cycle. C666001CDNA Ligase50 µL-20℃.Avoid freeze/thaw cycle. C666001DDigestion Buffer20 µL-20℃.Avoid freeze/thaw cycle. C666001EDigestion Enzyme I70 µL-20℃.Avoid freeze/thaw cycle. C666001FDigestion Enzyme III25 µL-20℃.Avoid freeze/thaw cycle. Box 2: Magnetic Beads for DNA Purification and RecoveryC666001Component16 TStorageC666001GCMPure4×1.5 mL2-8℃Products IntroductionThe Cyclization Kit is a modular kit tailored for the MGI high-throughput sequencing platform. With this kit, PCR products after junction ligation can be prepared into single-stranded circular DNA libraries suitable for MGI sequencers. All reagents provided in the kit have been subjected to stringent quality control and functional validation to maximize the stability and reproducibility of library construction. Provide your own instruments, reagents and consumables1. Magnetic frame: DynaMagTM-2 (Cat. No. 12321D) is recommended.2. "Qubit" 3.0 Fluorescence Quantimeter (ThermoFisher, Cat. No. Q33216)3. Qubit" ssDNA Assay Kit (Invitrogen, Cat. No. Q10212)4. Anhydrous ethanol, EB (10 mM Tris-HCl, pH 8.0), NF Water (pH between 7.0 and 8.0).5. reaction tubes: low adsorption PCR tubes with 1.5 mIEP tubes are recommended: 5.Tip: It is recommended to use a high quality filter tip to prevent contamination of kits and libraries. Pre-experiment Preparation and Important Notes 1. Sample preparation.PCR product: 2330 ng total (total amount when multiple PCR products are mixed) in a volume of 49 pL (if the volume of PCR product is insufficient, add NF Water to bring the total volume to 49 pl). -PCR product: Fragment size: The fragment peak is between 200-500 bp. -PCR product fragment size: Fragment peaks between 200-500 bp. -PCR product modification: Fixed sequences (with Index) for MGISEQ-2000, MGISEQ-200 and BGISEQ-500 sequencing platforms were added.2. Reagent preparation-Remove the corresponding reagents from the kit, centrifuge briefly, and place the enzyme mixture on ice until ready to use: buffers need to be dissolved at room temperature before use, then centrifuged with shaking and placed on ice until ready to use, and NF Water and EB are placed at room temperature until ready to use: "Please make up the mixture on ice:Precipitation may appear after the buffer in the kit is dissolved, the precipitation does not affect the function of the reagent, please shake and mix well until the precipitation disappears and then use. Schematic diagram of the cyclization process procedurecyclize 1. 1 wl of Splint Oligo was added to the 49JI PCR product. The product was denatured and incubated on a PCR instrument at 95°C for 3 min, then immediately transferred to an ice bath and allowed to stand for 2 min. 2. The reaction mixture was prepared on ice according to the following system. 3. Add 15ul of the above reaction mixture to 50µl of denatured DNA.4. Place the above PCR tubes on the PCR instrument under the following conditions Reaction. digest 1. Prepare the digestion reaction solution on ice according to the following system. 2. After the cyclization reaction, add 8l of digestion reaction solution directly to the cyclization system, mix well, centrifuge briefly and then place the PCR tube on the PCR instrument and react under the following conditions. 3. Purification was carried out immediately after the reaction.Purification of digestive products1. Remove CMPure at room temperature 30 minutes prior to use and mix well with shaking.2. Transfer the digested product to a 1.5 mIEP tube, pipette 340 pICMPure into the digested product, mix well by gently blowing 10 times with a pipette and incubate for 10 minutes at room temperature.3. Instantaneous centrifugation, place the EP tube on a magnetic rack and let stand for 5 minutes until the liquid is clear, pipette and discard the supernatant.4. Keep the EP tube fixed on a magnetic rack, add 250ul of freshly prepared 80% ethanol, let it stand at room temperature for 1 minute, then carefully discard the supernatant.5. Repeat step 4 once, try to suck up the liquid at the bottom of the tube: Note: Do not suck up the magnetic beads, so as not to affect the yield.6. Keep the EP tube fixed on the magnetic rack, open the cap and dry it at room temperature for 5-10 minutes.7. Remove the EP tube from the magnetic rack, add 35ul of EB or NF Water for DNA elution, pipette blow to mix and dissolve at room temperature for 10 min.8. Centrifuge instantaneously, place the EP tube on a magnetic rack and let stand for 2 minutes until the liquid is clarified, transfer the supernatant to a new EP tube. -Store at 20C and leave to prepare DNB... Read More | FFPE DNA/RNA KitFixed Tissue DNA/RNA Extraction Kit Catalog number: F666120 (50 preps)Storage conditions: DNase I and 10×Reaction Buffer -20℃, Spin Columns DF and Spin Columns RS can be stored at room temperature for 2 months, 2-8℃ for 1 year, the rest of the components are stored FFPE DNA/RNA KitFixed Tissue DNA/RNA Extraction Kit Catalog number: F666120 (50 preps)Storage conditions: DNase I and 10×Reaction Buffer -20℃, Spin Columns DF and Spin Columns RS can be stored at room temperature for 2 months, 2-8℃ for 1 year, the rest of the components are stored at room temperature (15-30℃).Products Content:Products IntroductionThis kit is suitable for the effective purification of genomic DNA and total RNA from paraffin-embedded tissues, using specially optimized deparaffinizing agents and lysates to release DNA and RNA from tissue section samples, without the use of the organic reagent xylene, and without the need for overnight operation; the digested samples are incubated at higher temperatures to remove inhibitors caused by cross-linking, which can effectively improve nucleic acid yields and purity; and an optimized buffer system allows nucleic acids in the lysate to bind specifically to the adsorbent membrane, and inhibitors are effectively removed by a two-step rinsing procedure. The optimized buffer system enables the nucleic acids in the lysate to bind specifically to the adsorbent membrane, and the inhibitors are effectively removed by a two-step rinsing step, and finally eluted with low-salt buffer or water to obtain high purity DNA and RNA, and at the same time, equipped with a high-efficiency microsorbent column, the volume of the elution can be as low as 20 µl. The purified DNA and RNA can be directly used for PCR, Real-time PCR, SNP genotyping, STR genotyping, and so on. The purified DNA and RNA can be directly used for PCR, Real-time PCR, SNP genotyping, STR genotyping, second-generation sequencing, pharmacogenomics research and blot analysis.Self-contained reagent: anhydrous ethanolPre-experiment Preparation and Important Notes 1. After obtaining the sample, fix the sample as soon as possible, the fixation time of 14-24 hours is appropriate, too long a period of time will easily lead toDNA and RNA breaks, affecting downstream experiments. If the formaldehyde fixation time is too long or the sample is stored for too long(>1 year) is prone to compromise DNA integrity and failure to amplify long fragments.2. Ensure that samples are thoroughly dehydrated prior to embedding; residual formalin will inhibit Proteinase K action.3. Add 1.25 ml of Proteinase K Storage Buffer to Proteinase K to dissolve it, and store at -20℃. Do not leave the prepared Proteinase K at room temperature for a long period of time to avoid affecting its activity.4. Anhydrous ethanol should be added to Buffer RW2, Buffer GW1 and Buffer GW2 according to the label instructions on the vials before first use.5. Check Buffer GTL, Buffer GL and Buffer DS for crystallization or precipitation prior to use; if crystallization or precipitation occurs, redissolve Buffer GTL, Buffer GL and Buffer DS in a 37°C water bath.6. Preheat the water bath or thermostatic mixer to 56°C before starting the experiment.7. Use an ambient temperature centrifuge or set the centrifuge temperature to 25°C. Temperatures below 15°C may result in clogging of the adsorption column.8. To prevent RNase contamination, the following should be observed:1) Use RNase-free plastics and tips to avoid cross-contamination.(2) Glassware should be dry baked at 180°C for 4 hours before use, plasticware can be soaked in 0.5 M NaOH for 10 minutes, rinsed thoroughly with water and autoclaved.3) RNase-free water should be used to prepare the solution.(4) Operators wear disposable masks and gloves, and change gloves diligently during the experiment.procedureParaffin-embedded samples1. Trim off excess paraffin from the tissue block to expose the tissue and cut into 5-10 µm slices.2. Place approximately 1 x 1 cm2 slices (1-5 slices in total) in a centrifuge tube (supplied), add 500 µl of Buffer DS and vortex for 10 s. Briefly centrifuge the sample to the bottom of the tube. Centrifuge briefly to collect the sample at the bottom of the tube, incubate at 56°C for 3 minutes, remove from the water bath and allow to cool to room temperature before proceeding.Note: If the surface of the sample is exposed to air, discard the initial 2-3 slices without using them.3. Centrifuge at 12,000 rpm for 2 minutes and carefully discard the supernatant thoroughly without aspirating the precipitate. The residual dewaxing solution can be carefully removed with a small tip (10 µl).4. Add 180 µl of Buffer GTL and 20 µl of Proteinase K to the above tube and mix well with vortexing.5. Incubate at 56°C for 15 minutes, then place on ice for 3 minutes. Centrifuge at 12,000 rpm for 15 minutes at room temperature.6. Transfer the supernatant to a new 1.5 ml centrifuge tube for RNA extraction, taking care not to aspirate undigested tissue. Use the precipitate for DNA extraction. RNA extraction7. Take the supernatant obtained in step 6 and incubate at 80°C for 15 minutes.8. Add 320 µl of Buffer GL, mix by vortexing and shaking, then add 720 µl of anhydrous ethanol and mix immediately by vortexing and shaking.9. Add all of the resulting solution to the Spin Columns RS in the collection tube; if the solution cannot be added all at once, it may be transferred in several passes. centrifuge the column at 12,000 rpm for 1 minute, pour off the waste solution from the collection tube, and place the column back into the collection tube. Note: If the columns are clogged, the sample size may be too large and consideration should be given to reducing the number of starting sections to 1-2.Optional step: If genomic DNA is to be removed, the following steps can be followeda. Add 350 µl of Buffer RW1 to the column, centrifuge at 12,000 rpm for 1 minute, discard the waste solution, and place the column back into the collection tube.b. Preparation of DNase I mixture: Take 52 µl of RNase-Free Water and add 8 µl of 10×Reaction to it.Buffer and 20 µl DNase I (1 U/µl), mix well, and prepare a final volume of 80 µl of reaction solution.c. Add 80 µl of DNase I Mix directly to the adsorption column and incubate at 20-30°C for 15 minutes.d. Add 350 µl of Buffer RW1 to the column, centrifuge at 12,000 rpm for 1 minute, discard the waste solution, and return the column to the collection tube.Add 500 µl of Buffer RW2 to the adsorbent column, centrifuge at 12,000 rpm for 1 min, pour off the waste liquid in the collection tube, and put the adsorbent column back into the collection tube.11. Repeat step 10. centrifuge at 12,000 rpm for 2 minutes and pour off the waste liquid in the collection tube. Place the column at room temperature for 5 minutes.minutes to dry thoroughly.12. Place the column in a new RNase-free centrifuge tube and add 20-50 µl to the center of the column.RNase-Free Water, left at room temperature for 5 minutes, centrifuged at 12,000 rpm for 1 minute, and collected RNA solution, the-80°C for storage.DNA extraction7. Take the precipitate obtained in step 6 and add 180 µl Buffer GTL and 20 µl Proteinase K to the precipitate. VortexResuspend the precipitate for 15 seconds.8. Incubate at 56°C for 1 hour until the sample is completely dissolved. 90°C for 1 hour.Add 200 µl Buffer GL, vortex and shake to mix and then add 200 µl anhydrous ethanol, vortex and shake to mix thoroughly. Centrifuge briefly so that the solution on the wall of the tube collects at the bottom of the tube. Add all of the solution from step 9 to the Spin Columns DF in the collection tube, or transfer the solution in several passes. centrifuge at 12,000 rpm for 1 minute, pour off the waste solution from the collection tube, and return the column to the 10. collection tube.Note: If the adsorption column is clogged, the sample size may be too large and consideration should be given to reducing the number of starting sections to 1-2.11. Add 500 µl of Buffer GW1 to the adsorbent column and 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.12. Add 500 µl of Buffer GW2 to the adsorbent column and centrifuge at 12,000 rpm for 1 minute. Pour off the waste liquid from the collection tube and place the column back into the collection tube.Note: Step 12 may be repeated if further purity is required.13. 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 5 minutes to dry thoroughly. Note: The purpose of this step is to remove residual ethanol from the adsorbent column; ethanol residue will affect the subsequent enzymatic reaction. 14. Place the column in a new 1.5 ml centrifuge tube, add 20-50 µl Buffer EB to the center of the column, leave at room temperature for 5 minutes, centrifuge at 12,000 rpm for 1 minute, collect the DNA solution, and store at -20℃... Read More | Product contentcomponent50T200TBuffer LP125mL100mLBuffer LP210mL40mLBuffer LP3 (concentrate)21ml84mlBuffer GW2 (concentrate)15mL75mlBuffer GE15mL60mLRNase A（10 mg/ml）300µl1.25mLSpin Columns DM with Collection Tubes50200ProductsThis kit uses centrifugal adsorption columns with highProduct contentcomponent50T200TBuffer LP125mL100mLBuffer LP210mL40mLBuffer LP3 (concentrate)21ml84mlBuffer GW2 (concentrate)15mL75mlBuffer GE15mL60mLRNase A（10 mg/ml）300µl1.25mLSpin Columns DM with Collection Tubes50200ProductsThis kit uses centrifugal adsorption columns with high efficiency and specific binding of nucleic acids and a unique buffer system, which is suitable for extracting genomic DNA from a wide variety of different fresh or frozen plant tissues with maximum removal of impurities from the plant tissues. The kit eliminates the need for phenol/chloroform extraction and is safe to handle. The extracted genomic DNA fragments are large, high purity, stable and reliable quality, suitable for PCR, fluorescence quantitative PCR, molecular labeling, library construction and other experiments.Self-contained reagent: anhydrous ethanolPre-experiment Preparation and Important Notes1. Repeated freezing and thawing of the sample should be avoided, as this may result in smaller fragments of extracted DNA and a decrease in the amount extracted.2. Anhydrous ethanol should be added to Buffer LP3 and Buffer GW2 according to the instructions on the label of the reagent bottle before first use. Check Buffer LP1 and Buffer LP2 for crystallization or precipitation before use. If crystallization or precipitation occurs, re-dissolve Buffer LP1 and Buffer LP2 in a 56°C water bath. Procedure1. Take about 100mg of fresh plant tissue or about 20mg of dry weight tissue and add liquid nitrogen to grind it fully.2. Collect the ground powder into a centrifuge tube (self-provided), add 400 µl Buffer LP1 and 6 µl RNase A (10 mg/ml), vortex and oscillate for 1 minute, and leave it at room temperature for 10 minutes to allow for full cleavage.Note: 1) Use vortex shaking or pipette blowing to fully lyses the tissue, incomplete tissue lysis will affect the final DNA yield. 2) Do not mix Buffer LP1 with RNase A prior to use.3. Add 130 µl Buffer LP2, mix well and vortex for 1 minute.4. Centrifuge at 12,000 rpm (~13,400 x g) for 5 minutes and transfer the supernatant to a new centrifuge tube (supplied).5. Add 1.5 times the volume of Buffer LP3 (check that anhydrous ethanol has been added before use) and mix thoroughly (e.g., 500 µl filtrate to 750 µl Buffer LP3).Note: Buffer LP3 should be mixed immediately after addition; precipitation may occur but will not affect subsequent experiments.6. Add all of the solution and precipitate obtained in the previous step to the adsorption columns (Spin Columns DM) that have been loaded into the collection tubes, if the solution cannot be added all at once, it can be transferred in several times. centrifuge the columns at 12,000 rpm for 1 minute, pour off the waste liquid in the collection tubes, and put the columns back into the collection tubes.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: If the adsorbent membrane appears green, add 500 µl of anhydrous ethanol to the adsorbent column, centrifuge the column at 12,000 rpm for 1 minute, pour off the waste liquid in the collection tube, and put the adsorbent column back into the collection tube.8. Repeat step 7.9. Centrifuge at 12,000 rpm for 2 minutes and pour off the waste liquid in the collection tube. Leave the adsorption column at room temperature for several minutes to dry thoroughly.Note: The purpose of this step is to remove residual ethanol from the adsorption column, which can interfere with subsequent enzymatic reactions (digestion, PCR, etc.).10. Place the adsorption column in a new centrifuge tube (supplied), add 50-100 µl of Buffer GE or sterilized water dropwise to the middle of the adsorbent membrane, leave it at room temperature for 2-5 minutes, and centrifuge it at 12,000 rpm for 1 minute to collect the DNA solution. -The DNA solution was collected by centrifugation at 12,000 rpm for 1 min.Note: 1) If the downstream experiment is sensitive to pH or EDTA, you can use sterilized water for elution. The pH value of the eluent has a great influence on the elution efficiency, if you use water as the eluent, you should ensure that the pH value is 7.0-8.5 (you can use NaOH to adjust the pH value of the water to this range), and when the pH value is lower than 7.0, the elution efficiency is not high.2) Incubation at room temperature for 5 minutes prior to centrifugation increases yield.(3) If the final concentration of DNA is to be increased, the DNA eluate obtained in step 10 can be re-added to the adsorbent membrane and repeat step 10; if the elution volume is less than 100µl, the final concentration of DNA can be increased, but it may reduce the total DNA yield. If the amount of DNA obtained is less than 1µg, 50µl Buffer GE is recommended for elution.4) Because DNA stored in water is subject to acidic hydrolysis, for long-term storage, elution with Buffer GE and storage at -20°C are recommended... 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 |