| Description | Annexins are a family of calcium-dependent phospholipid-binding proteins that preferentially bind phosphatidylserine (PS). Under normal physiologic conditions, PS is predominantly located in the inner leaflet of the plasma membrane. Upon initiation of apoptosis, PS loses its asymmetric Annexins are a family of calcium-dependent phospholipid-binding proteins that preferentially bind phosphatidylserine (PS). Under normal physiologic conditions, PS is predominantly located in the inner leaflet of the plasma membrane. Upon initiation of apoptosis, PS loses its asymmetric distribution across the phospholipid bilayer and is translocated to the extracellular membrane leaflet marking cells as targets of phagocytosis. Once on the outer surface of the membrane, PS can be detected by fluorescently labeled Annexin V in a calcium-dependent manner. In early-stage apoptosis, the plasma membrane excludes viability dyes such as propidium iodide (PI), 7-AAD. These cells will stain with Annexin V but not a viability dye, thus distinguishing cells in early apoptosis. However, in late stage apoptosis, the cell membrane loses integrity thereby allowing Annexin V to also access PS in the interior of the cell. A viability dye can be used to resolve these late-stage apoptotic and necrotic cells (Annexin V, viability dye-positive) from the early-stage apoptotic cells (Annexin V positive, viability dye-negative). This kit is suitable for the identification and enumeration of dead cells, such as apoptotic or necrotic cells, by flow cytometry.A1372287Components20T50T100TStorageQuantity Per TestA1372287A10X Annexin V Binding Buffer5 mL10 mL20 mL2-8℃200 µL per 0.5–1.0 × 10⁵ cells.A1372287BAnnexin V (APC)100 µL250 µL500 µL2-8℃. Store in the dark.5 µL per 0.5–1.0 × 10⁵ cells.A1372287CPropidium iodide Staining Solution (PI)100 µL250 µL500 µL2-8℃. Store in the dark.2 µL per 0.5–1.0 × 10⁵ cells.Note: The recommended number of cells to stain per test is 0.5–1.0 × 10⁵ cells.Instruction for use1. Dilute 10X Binding Buffer to 1X using distilled water (1 mL 10X Binding Buffer + 9 mL ddH2O).2. Wash cells twice with cold PBS and then resuspend the desired amount of cells in Annexin V Binding Buffer at a concentration of 0.5–1.0×10⁶/mL.3. Add 5 µl of FITC Annexin V and 2 µl PI to 100 µL of the cell suspension4. Gently vortex the cells and incubate for 10 min at RT (25°C) in the dark.5. Add 100 µl of 1X Binding Buffer to each assay. Analyze by flow cytometry within 1 hr... Read More | Product introduction：Dualucif The firefly & Renilla assay kit (dual luciferase reporter assay kit) provides an effective means to detect the expression of genes. In DLR detection, the activities of firefly luciferase and Renilla luciferase can be detected in a single sample in turn. FirstProduct introduction：Dualucif The firefly & Renilla assay kit (dual luciferase reporter assay kit) provides an effective means to detect the expression of genes. In DLR detection, the activities of firefly luciferase and Renilla luciferase can be detected in a single sample in turn. First, luciferin was used as substrate to detect the activity of firefly luciferase, then substances inhibiting the catalysis of firefly luciferase were added, and coelenterazine was added to detect the activity of Renilla luciferase to achieve dual luciferase reporter gene detection. The bioluminescence system of luciferase and its substrate can detect gene expression very sensitively and efficiently. Usually, the transcriptional regulatory element or 5'promoter region of the gene of interest is cloned upstream of luciferase, or the 3'-utr region is cloned downstream of luciferase to construct a reporter gene plasmid, and then transfect the cells. After the cells are treated with appropriate drugs, the cells are lysed, and the transcriptional regulation effect of drug treatment on the target gene is judged by detecting the luciferase activity. Renilla luciferase is more often used as an internal reference for detecting transfection efficiency to eliminate the difference in cell number and transfection efficiency. Firefly luciferase is a protein with a molecular weight of about 61 kDa. In the presence of ATP, magnesium ions and oxygen, it can catalyze the production of oxyluciferin from luciferin. In the process of luciferin oxidation, it will produce a light signal. Renilla luciferase is a protein with a molecular weight of about 36 kDa. In the presence of oxygen, it can catalyze the oxidation of coelenteramide to coelenteramide, and also produce light signals in the process of coelenteramide oxidation. The optical signal of this kit can be measured by chemiluminescence instrument, microplate reader or liquid scintillation tester. The kit has the characteristics of rapid detection, high sensitivity, wide detection range and no interference of cell endogenous activity.Instruction：1.Cell lysis ( 1 ) Remove the medium and gently wash twice with PBS ( adherent cells can be operated directly, suspension cells need to be centrifuged to collect cells ). Add 1 × Lysis Buffer ( diluted component A with sterile water at 4 : 1 ) according to the following scheme, and then place the culture plate on a micro-oscillator at room temperature for 15 min to fully lyse the cells. Note : The pyrolysis products can be stored at room temperature for 6 h, and can be stored at − 70 °C for a long time ( the pyrolysis products cannot be repeatedly frozen and thawed ). ( 2 ) The pyrolysis products were centrifuged at 10000-15000 rpm for 3-5 min. After centrifugation, the supernatant was transferred into a new EP tube for subsequent detection. Note : Cells can be detected immediately after lysis, or frozen, and re-detected when needed. The frozen samples need to be thawed to room temperature for detection. 2. Preparation of working fluid ( 1 ) Restore all components to room temperature. ( 2 ) Dilute component C with component B to 0.2 mg / mL firefly luciferase working solution. Note : The firefly luciferase working solution cannot be repeatedly frozen and thawed. If the amount of a single experiment is small, it is recommended to be subpackaged into small specifications according to a single amount of use. ( 3 ) The E component was diluted into the renilla luciferase working solution with the D component, and the dilution method was 1 µL E component was added to the 49 µL D component. Note : Renilla luciferase working solution needs to be prepared now. 3.chemiluminescence value detection ( 1 ) According to the operation instructions of the instrument, the instrument with chemiluminescence detection function was opened, such as multifunctional microplate reader. The parameters were set, the determination time was 10 s, and the determination interval was 2 s. ( 2 ) each sample determination, take the sample 20-100 µL ( if the sample volume is enough, please add 100 µL ; if the sample amount is insufficient, the amount can be appropriately reduced, but the amount of detection holes needs to be consistent ). 1 × Lysis Buffer was blank control. ( 3 ) 100 µL firefly luciferase working solution was added to determine the RLU ( relative light unit ) value ( it is recommended that the microplate reader set up the Shaking mixing function ). Note : Since the luminescence is instantaneous, it is recommended to detect immediately after adding the firefly luciferase working solution. ( 4 ) 100 µL renilla luciferase working solution was added to determine the RLU ( relative light unit ) value ( Shaking mixing function is recommended for microplate reader ). ( 5 ) In the case of renilla luciferase as an internal reference, the RLU value measured by firefly luciferase was divided by the RLU value measured by renilla luciferase. According to the obtained ratio, the activation degree of the target reporter gene between different samples was compared. If firefly luciferase is used as an internal reference, similar calculations can also be performed.Component：Recommendation：It is recommended to use component B in advance to prepare 2 mg / mL storage solution, component B, component D and component C prepared as storage solution, and to carry out small batch packing according to the experimental requirements. All test working fluids are recommended to be used now to avoid repeated freezing and thawing.Matters needing attention：1. please centrifuge the product to the bottom of the tube immediately before use, and then conduct subsequent experiments. 2. in order to obtain the best determination effect, when using a single tube chemiluminescence instrument for determination, the time from the mixing of sample and determination reagent to the pre determination should be controlled as much as possible; When using a multi-functional fluorescent microplate reader with chemiluminescence detection function, it is advisable to add all samples first, and then uniformly add firefly luciferase detection reagent. 3. the strongest wavelength of firefly luciferase catalyzed bioluminescence is 560 nm, and the strongest wavelength of Renilla luciferase catalyzed bioluminescence is 480 nm. 4. to prevent interference between holes, it is recommended to use white opaque orifice plate. 5. due to the influence of temperature on enzyme reaction, the sample and reagent should be measured after reaching room temperature. 6. for your safety and health, please wear experimental clothes and disposable gloves.Scope of application：Study on gene expression regulation and promoter... Read More | M666110 Component 96 T Storage M666110A Buffer WSL 40 mL RT M666110B Buffer MSL 40 mL RT M666110C Buffer CW1 (concentrate) 90 mL RT M666110D Buffer GW1 (concentrate) 40 mL RT M666110E Buffer GW2 (concentrate) 50 mL RT M666110F Buffer EB 30 mL RT M666110G Proteinase K 4×1.25 mL RT M666110H M666110 Component 96 T Storage M666110A Buffer WSL 40 mL RT M666110B Buffer MSL 40 mL RT M666110C Buffer CW1 (concentrate) 90 mL RT M666110D Buffer GW1 (concentrate) 40 mL RT M666110E Buffer GW2 (concentrate) 50 mL RT M666110F Buffer EB 30 mL RT M666110G Proteinase K 4×1.25 mL RT M666110H Magbeads V3 2×1 mL RTProduct Introduction：The reagent kit provides a simple, fast, and efficient method for extracting genomic DNA from blood samples. In the presence of high salt, DNA binds to the surface of silica coated Magheads. After rinsing, high-purity DNA is eluted in Buffer EB or deionized water. The purified DNA has good purity (A260/280 ratio between 1.7-1.9) and high integrity (>15 kb), and can be used for downstream experiments such as second-generation sequencing, quantitative PCR, and chip detection.Self provided instruments and reagents1) Constant temperature mixer2) 2/15 ml magnetic frame3) 32 channel nucleic acid extractor4) 96 channel nucleic acid extractor5) 96 DW Plate6) 8 channel Comb7) Spin tips pack8) Anhydrous ethanolPreparation and important precautions before the experiment1.Before the first use, add anhydrous ethanol to Buffer CW1, Buffer GW1, and Buffer GW2 according to the label of the reagent bottle and mark them properly.2.Magheads are strictly prohibited from freezing or centrifugation. Freezing and centrifugation may cause irreversible damage to Magheads.Operation stepsI. Manual single tube operation1. Use punching forceps to take 1 blood spot with a diameter of 6 mm or 4 blood spots with a diameter of 3 mm (depending on the actual situation) from the blood spot and place them in a 2.0 mL centrifuge tube.2. Add 40 to the centrifuge tube µ L Protein K and 300 µ L Buffer WSL, then place the centrifuge tube on a constant temperature mixer at 75 ℃ and 1200 rpm, shake and crack for 45 minutes to form Lysate. Remove the centrifuge tube from the constant temperature mixer, centrifuge briefly, and take the supernatant.Attention: If there is no constant temperature mixer, vortex the centrifuge tube for 10 seconds and incubate it in a 75 ℃ water bath for 30 minutes. During this period, vortex every 10 minutes for 10 seconds.3. Suck the supernatant into a new 2.0 mL centrifuge tube and add 300 µ L Buffer MSL, 300 µ L isopropanol and 20 µ L Magheads V3. Afterwards, place the centrifuge tube on a constant temperature mixer at 25 ℃ and 1600 rpm, shake and crack for 15 minutes, or invert the centrifuge tube and mix continuously for 15 minutes.4. Place the centrifuge tube on a magnetic stand and let it stand for 1 minute. After Magheads are completely adsorbed on the side wall of the centrifuge tube, discard the solution thoroughly (keep the centrifuge tube fixed on the magnetic stand).5. Remove the centrifuge tube from the magnetic frame and add 900 µ L Buffer CW1 (please check if anhydrous ethanol has been added before use), vortex point shake for 1 minute or vortex shake for 5 seconds, and then place it on a constant temperature mixer at 25 ℃ and 1600 rpm to shake and mix for 2 minutes (ensure that Magheads are in a mixed state during the shaking process). Afterwards, place the centrifuge tube on a magnetic stand and let it stand for 1 minute. After Magheads are completely adsorbed on the side wall of the centrifuge tube, gently invert the magnetic stand and wash the impurities on the centrifuge tube cover to completely discard the solution (keep the centrifuge tube fixed on the magnetic stand).6. Remove the centrifuge tube from the magnetic frame and add 500 µ L Buffer GW1 (please check if anhydrous ethanol has been added before use), vortex point shake for 1 minute or vortex shake for 5 seconds, and then place it on a constant temperature mixer at 25 ℃ and 1600 rpm to shake and mix for 2 minutes (ensure that Magheads are in a mixed state during the shaking process). Afterwards, place the centrifuge tube on a magnetic stand and let it stand for 1 minute. After Magheads are completely adsorbed on the side wall of the centrifuge tube, gently invert the magnetic stand and wash the impurities on the centrifuge tube cover to completely discard the solution (keep the centrifuge tube fixed on the magnetic stand).7. Remove the centrifuge tube from the magnetic frame and add 900 µ L Buffer GW2 (please check if anhydrous ethanol has been added before use), vortex point shake for 1 minute or vortex shake for 5 seconds, then place it on a constant temperature mixer at 25 ℃ and 1600 rpm, shake and mix for 2 minutes (ensure that Magheads are in a mixed state during the shaking process). Afterwards, place the centrifuge tube on a magnetic stand and let it stand for 1 minute. After Magheads are completely adsorbed on the side wall of the centrifuge tube, gently invert the magnetic stand and wash the impurities on the centrifuge tube cover to completely discard the solution (keep the centrifuge tube fixed on the magnetic stand).8. Remove the centrifuge tube from the magnetic frame and add 300 µ After shaking with 75% ethanol for 1 minute or 5 seconds, place the mixture on a constant temperature mixer at 25 ℃ and 1600 rpm for 2 minutes (ensure that the Magheads are in a mixed state during the shaking process). Afterwards, place the centrifuge tube on a magnetic stand and let it stand for 1 minute. After Magheads are completely adsorbed on the side wall of the centrifuge tube, gently invert the magnetic stand and wash the impurities on the centrifuge tube cover to completely discard the solution (keep the centrifuge tube fixed on the magnetic stand).9. Keep the centrifuge tube fixed on the magnetic frame, use a pipette to further remove the solution from the bottom and cover of the centrifuge tube, and then leave it at room temperature for 5-10 minutes to allow the ethanol to evaporate completely.10. Remove the centrifuge tube from the magnetic frame and add 50-200 µ L Buffer EB. Vortex oscillation causes the magnetic beads to completely suspend in the eluent and then place them on a constant temperature mixer at 56 ℃ and 1600 rpm for 10 minutes of shaking and elution, or incubate the centrifuge tube in a 56 ℃ water bath for 10 minutes, with vortex oscillation every 3 minutes for 10 seconds.11. Place the centrifuge tube on a magnetic stand and let it stand for 2 minutes. After Magheads are completely adsorbed on the side wall of the centrifuge tube, transfer the eluent to a new centrifuge tube using a pipette and store at -20 ℃ for later use.II. Matching with CWE21001. Use punching forceps to take 1 blood spot with a diameter of 6 mm or 4 blood spots with a diameter of 3 mm (depending on the actual situation) from the blood spot and place them in a 2.0 mL centrifuge tube.2. Add 40 to the centrifuge tube µ L Protein K and 300 µ L Buffer WSL, then place the centrifuge tube on a constant temperature mixer at 75 ℃ and 1200 rpm, shake and crack for 45 minutes to form Lysate.3. Add the corresponding reagents to the 96DW deep well plate according to the table below. Position Reagent 1&7 Colume Lysate: All Buffer MSL: 300 µL isopropanol：300 µL Magbeads V3: 20 µL 2&8 Colume Buffer CW1: 900 µL 3&9 Colume Buffer GW1: 500 µL 4& 10 Colume Buffer GW2: 900 µL 5& 11 Colume 75%ethanol: 300 µL 6& 12 Colume Buffer EB: 70 µL4.Place the deep well plate and magnetic sleeve that have been added to the reagent at the corresponding positions of CWE2100/CWE3200, run the blood slide extraction program, and after about 40 minutes, the program ends. Remove the deep well plate and magnetic sleeve.5.Transfer the elution products from columns 6 and 12 of the deep well plate to a 1.5 mL centrifuge tube for low-temperature storage.III. Matching with CWE9601. Use punching forceps to take 1 blood spot with a diameter of 6 mm or 4 blood spots with a diameter of 3 mm (depending on the actual situation) from the blood spot and place them in a 2.0 mL centrifuge tube.2. Add 40 to the centrifuge tube µ L Protein K and 300 µ L Buffer WSL, then place the centrifuge tube on a constant temperature mixer at 75 ℃ and 1200 rpm, shake and crack for 45 minutes to form Lysate.3. Add the corresponding reagents to the 96DW deep well plate according to the table below Position Reagent Plate 1 Lysate: All Buffer MSL: 300 µL isopropanol ：300 µL Magbeads V3: 20 µL Plate 2 Buffer CW1: 900 µL Plate 3 Buffer GW1: 500 µL Plate 4 Buffer GW2: 900 µL Plate 5 75% ethanol : 300 µL Plate 6 Buffer EB: 70 µL4. Place the deep well plate and magnetic sleeve that have been added to the reagent at the corresponding positions on CWE960, run the blood slide extraction program, and after about 40 minutes, the program ends. Remove the deep well plate and magnetic sleeve.5. Transfer the elution products from Plate 6 to a 1.5 mL centrifuge tube for low-temperature storage... Read More | DescriptionMetathesis: Ruthenium-Based Metathesis CatalystsRuthenium metathesis catalysts kit I consists of 9 samples of Grubbs 1st and 2nd generation catalysts. These catalysts have applications in ring-closing and ring-opening metathesis, cross-metathesis, ring-opening metathesis polymerization (DescriptionMetathesis: Ruthenium-Based Metathesis CatalystsRuthenium metathesis catalysts kit I consists of 9 samples of Grubbs 1st and 2nd generation catalysts. These catalysts have applications in ring-closing and ring-opening metathesis, cross-metathesis, ring-opening metathesis polymerization (ROMP) and enyne metathesis.Metathesis: Ruthenium-Based Metathesis Catalysts... 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 |