| Description | Calcium, the most abundant mineral in the human body, is a crucial intracellular element that is responsible for regulating many physiological and pathological processes. Calcium is found in either the free ion form or in bound complexes, for example the calcium phosphate and calcium carbonate Calcium, the most abundant mineral in the human body, is a crucial intracellular element that is responsible for regulating many physiological and pathological processes. Calcium is found in either the free ion form or in bound complexes, for example the calcium phosphate and calcium carbonate complexes that make up bone tissue. Numerous physiological processes, including muscle contraction, cell adhesion, hormones/ neurotransmitters release, glycogen metabolism, cell proliferation/differentiation, blood clotting, nerve or synapthetic impulse transmission, and structural support of the skeleton are regulated by calcium signaling. Defects in the integrity of cell-specific calcium signaling systems may be associated with certain human diseases.Calcium Colorimetric Assay kit has been used to measure calcium concentration in hippocampal samples and MC3T3-E1 mouse osteoblast cell line, which were cultured in osteogenic induction medium... Read More | 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 | 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 | G665573 Component 10 T Storage G665573A Buffer P1 30 mL RT G665573B Buffer P2 30 mL RT G665573C Buffer E3 30 mL RT G665573D Buffer PS 15 mL RT G665573E Buffer PW (concentrate) 10 mL RT G665573F Endo-Free Buffer EB 30 mL RT G665573G RNase A (10 mg/mL) 600 碌L RT G665573H Endo-Remover FX 10 EA G665573 Component 10 T Storage G665573A Buffer P1 30 mL RT G665573B Buffer P2 30 mL RT G665573C Buffer E3 30 mL RT G665573D Buffer PS 15 mL RT G665573E Buffer PW (concentrate) 10 mL RT G665573F Endo-Free Buffer EB 30 mL RT G665573G RNase A (10 mg/mL) 600 碌L RT G665573H Endo-Remover FX 10 EA RT G665573I Plungers 10 EA RT G665573J Spin Columns DX with Collection Tubes 10 EA RT G665573K Centrifuge Tubes (15 mL) 10 EA RTProduct IntroductionThis kit is specially designed for the efficient and rapid extraction of plasmids from 15-50 ml of bacterial fluids. On the basis of cell lysis by alkaline lysis method, it adopts unique silicon matrix membrane adsorption technology to bind plasmid DNA efficiently and exclusively, and each adsorption column can adsorb up to 250 µg of plasmid DNA; at the same time, it adopts a special buffer system and endotoxin removal filter to effectively remove endotoxin, genomic DNA, RNA, protein and other impurities. The plasmids obtained from this kit are of high purity and stable quality, and can be used for cell transfection, as well as DNA sequencing, PCR, in vitro transcription, endonuclease digestion and other experiments.Self-contained reagents: anhydrous ethanol, isopropanol.Pre-experiment Preparation and Important Notes1. All components are stable for 1 year in a dry, room temperature (15-30°C) environment, and longer by placing the adsorption columns at 2-8°C. Buffer P1 with RNase A is stable for 6 months at 2-8°C.2. Before the first use, add all of the RNase A solution to Buffer P1, mix well, and store at 2-8°C. Before use, it needs to be left at room temperature for a period of time, return to room temperature and then use.3. Anhydrous ethanol should be added to Buffer PW before the first use according to the instructions on the reagent bottle label.4. Please check Buffer P2 and Buffer E3 for crystallization or precipitation before use. If there is any crystallization or precipitation, the clarification can be restored by taking a water bath at 37℃ for a few minutes.5. Be careful not to touch Buffer P2 and Buffer E3 directly, and tighten the lid immediately after use.6. The amount and purity of extracted plasmid is related to the concentration of bacterial culture, strain type, plasmid size, plasmid copy number and other factors.7. The adsorption columns treated with Buffer PS should be used immediately to avoid leaving them for too long.Operation steps1.Take 15-50 ml of fresh bacterial solution from the overnight culture, add it to a centrifuge tube (self-prepared) and centrifuge at 5000 × g for 10 minutes to collect the bacteria, and aspirate all the supernatant as much as possible.2.Add 2.5 ml of Buffer P1 to the centrifuge tube in which the bacterial precipitate has been left (please check that RNase A has been added first) and suspend the bacterial precipitate by mixing thoroughly using a pipette or vortex shaker. Note: If the bacterial mass is not thoroughly mixed, it will affect the lysis effect and make the extraction amount and purity low.3.Add 2.5 ml of Buffer P2 to the centrifuge tube, mix gently up and down 8-10 times to fully lyse the organisms, and leave at room temperature for 3-5 minutes. At this point the solution should become clear and viscous. Note: Mix gently, do not shake vigorously, so as not to interrupt the genomic DNA and cause genomic DNA fragments to be mixed in the extracted plasmid. If the solution does not become clear, it suggests that the amount of bacteria may be too large and the lysis is not complete, and the amount of bacteria should be reduced.4.Add 2.5 ml of Buffer E3 to the centrifuge tube and mix immediately by turning up and down 8-10 times, at which time a white flocculent precipitate appears. Note: Buffer E3 should be mixed immediately after addition to avoid localized precipitation.5.Install the cap of the filter (Endo-Remover FX), transfer the solution obtained in step 4 to the filter, wait until the white flocculent precipitate floats on the upper layer of the solution, remove the cap of the filter, align the filter with a clean 15 ml centrifuge tube (supplied), and slowly push the handle (Plungers) to filter, so that as much as possible of the solution passes through, and the filtrate is collected in the centrifuge tube.6.Add 1/3 solution volume of isopropanol to the filtrate and mix upside down.7.Column Equilibrium: Add 1ml Buffer PS to the adsorption column (Spin Columns DX) that has been loaded into a 15ml centrifuge tube, centrifuge for 2 minutes at 2500 x g. Pour off the waste liquid from the centrifuge tube and put the adsorption column back into the centrifuge tube.8.The mixture of filtrate and isopropanol from step 6 was transferred to the equilibrated adsorption column (which had been loaded into a collection tube).9.Centrifuge at 2500 x g for 1 minute, pour off the waste solution in the collection tube and put the adsorption column back into the collection tube. Note: The maximum volume of the adsorption column is 4 ml, so the solution obtained in step 8 is passed through the column in 2 times.10.Add 2 ml of Buffer PW to the adsorption column (please check that anhydrous ethanol has been added first), centrifuge at 2500 × g for 1 min, and pour off the waste liquid in the collection tube.11.Repeat step 10.12.The adsorbent column was put back into the collection tube and centrifuged at 2500 × g for 2 min, the waste liquid was poured off, and the column was left to dry at room temperature for 5 min.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.)13. Place the adsorption column in a new 15 ml centrifuge tube, add 0.5-1 ml Endo-Free Buffer EB to the middle of the adsorbent membrane, leave it at room temperature for 2-5 minutes, centrifuge it at 2500 × g for 2 minutes, and collect the plasmid solution into the centrifuge tube. -20°C to store the plasmid.Note: 1) In order to increase the recovery efficiency of the plasmid, the obtained solution can be reintroduced into the adsorption column, left at room temperature for 2-5 minutes, centrifuged at 2500 x g for 2 minutes, and the plasmid solution can be collected into a centrifuge tube.2) When the plasmid copy number is low or >10kb, Endo-Free Buffer EB can increase the extraction efficiency by preheating at 65-70°C in a water bath... 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 |