| Description | Lactic acid is an important intermediate product in the metabolic processes of organisms, closely related to carbohydrate metabolism, lipid metabolism, protein metabolism, and intracellular energy metabolism. Lactic acid concentration is a key indicator for evaluating glycogen metabolism and aerobicLactic acid is an important intermediate product in the metabolic processes of organisms, closely related to carbohydrate metabolism, lipid metabolism, protein metabolism, and intracellular energy metabolism. Lactic acid concentration is a key indicator for evaluating glycogen metabolism and aerobic metabolism. Abnormally high concentrations of lactic acid are associated with pathological conditions such as cancer, diabetes, and lactic acidosis.The detection principle of this kit is as follows: Lactate dehydrogenase catalyzes the conversion of L-lactate to pyruvate, simultaneously reducing NAD+ to NADH and H+. Further, through the hydrogen transfer action of 1-mPMS, WST-8 reacts to form a yellow, soluble formazan. The absorbance at 450 nm is measured to calculate the L-lactate content in the sample.Detection Range: 0.03-2 mMSensitivity: 0.03 mMApplicable Samples: Animal and plant tissues, cells, bacteria, serum (plasma), or other liquids.L1501211Component48T96TStorageL1501211ALactate Assay Buffer70 mL70 mL×22-8℃L1501211BLactate Dehydrogenase0.7 mL1.4 mL-20℃L1501211CLactate Dehydrogenase Cofactor0.5 mL1 mL-20℃L1501211DWST-8350 µL700 µL-20℃. Store in the dark.L1501211EEnhancer70 µL140 µL-20℃. Store in the dark.L1501211FL(+)-Lactate Standard (100 mM)50 µL100 µL-20℃Please check the quantity of each component before the experiment.An additional 10% of each component is provided beyond the specified volume for standard curve preparation or preliminary experiments.User-Provided Instruments and ReagentsTypeNameNotesInstrumentMicroplate ReaderCapable of measuring absorbance at 450 nm.Consumables96-well MicroplateStandard transparent plate.ReagentsPBS (pH 7.4)For washing samples.OthersHomogenizer (for tissue samples), incubator, ice machine, low-temperature centrifuge, adjustable pipettes and tipsUsing a multichannel pipette for large-scale detection can improve efficiency.Experimental Procedure1. Reagent PreparationReagent NameReagent PreparationPrecautionsLactate Assay BufferReady-to-use; equilibrate to room temperature before use.4℃保存 Store at 4°C.Lactate DehydrogenaseReady-to-use;Keep on ice during the experiment; store aliquots at -20°C.Lactate Dehydrogenase CofactorReady-to-use;Keep on ice during the experiment; store aliquots at -20°C.WST-8Ready-to-use;Keep on ice during the experiment; store aliquots at -20°C.EnhancerReady-to-use;Keep on ice protected from light during the experiment; store aliquots at -20°C protected from light.L(+)-Lactate Standard (100 mM)Equilibrate to room temperature before use.100 mM, store aliquots at -20°C.2. Standard PreparationAdd 20 µL of the 100 mM standard to 980 µL of Lactate Assay Buffer to prepare a 2 mM standard stock solution. Aliquot and store at -20°C for up to 6 months. Dilute the 2 mM standard stock solution sequentially with Lactate Assay Buffer to prepare standard working solutions with final concentrations of 1 mM, 0.5 mM, 0.25 mM, 0.125 mM, 0.0625 mM, and 0.03125 mM. Use Lactate Assay Buffer as the blank.Standard Working SolutionStandard (µL)Lactate Assay Buffer (µL)Concentration (mM)1200 µL of 2 mM022200 µL of 2 mM20013200 µL of 1 mM2000.54200 µL of 0.5 mM2000.255200 µL of 0.25 mM2000.1256200 µL of 0.125 mM2000.06257200 µL of 0.0625 mM2000.03125Blank020003. Sample PreparationNote: Fresh samples are recommended. If not used immediately, samples can be stored at -80°C for up to 1 month. NADH or NADPH present in cell or tissue extracts can create background for lactate assay. To remove NADH or NADPH background, an equal amount of sample can be assayed without lactate dehydrogenase, and the background reading should be subtracted from the lactate reading. Endogenous lactate dehydrogenase (LDH) can degrade lactate. Samples containing LDH (e.g., cell culture medium, cell or tissue lysates) should be processed using a 10 kDa MW cutoff ultrafiltration tube (centrifuge at 12,000 g, 4°C for 10 min; follow the filter instructions) to remove all proteins. Use the filtrate for detection, then store at -80°C.3.1 Animal/Plant Tissues: Weigh approximately 0.1 g of tissue sample, add 1 mL of Lactate Assay Buffer, and homogenize on ice. Centrifuge at 12,000 g, 4°C for 5 min. Transfer the supernatant to a new tube and keep on ice for detection.3.2 Cells or Bacteria: Collect 5×10^6 cells. Wash the cells or bacteria with pre-cooled PBS. Centrifuge at 800 g for 2 min, discard the supernatant. Add 1 mL of Lactate Assay Buffer, and disrupt using an ultrasonic homogenizer on ice for 5 min (power 20% or 200 W, ultrasonic 3 s, interval 7 s, repeat 30 times). Centrifuge at 12,000 g, 4°C for 5 min. Collect the supernatant and keep on ice for detection.3.3 Plasma and Serum (Other Biological Fluids): Detect directly.4. Experimental Steps4.1 Microplate Reader Preparation: Preheat for at least 30 minutes, set wavelength to 450 nm.4.2 Working Reagent Preparation: 50 µL of Working Reagent is required per well. To avoid loss, prepare for 55 µL per single well system: Pipette 31 µL Lactate Assay Buffer, 8 µL Lactate Dehydrogenase Cofactor, 5 µL WST-8, 1 µL Enhancer, and 10 µL Lactate Dehydrogenase. Mix well. The Working Reagent must be prepared freshly and used immediately.4.3 Assay System Setup: Set up the detection system in the microplate according to the table below. The standard curve generally needs to be performed only once.ReagentStandard Well (µL)Test Well (µL)Sample050Standard Working Solution500Working Reagent50504.4 Absorbance Measurement: Mix well and incubate at 37°C protected from light for 30 min. Read the absorbance at 450 nm, recorded as Ablank, Astandard, and Atest. 5. Result CalculationThe following provides both the derived formula and the simplified calculation formula, which are completely equivalent.5.1 Data ProcessingCalculate ΔAstandard= Astandard- Ablank, ΔAtest = Atest - Ablank.5.2 Standard Curve PlottingPlot the standard curve with standard concentration as the y-axis and ΔAstandard as the x-axis. Substitute ΔAstandard into the equation to obtain the y value (mM).5.3 Sample L-Lactate Content Calculation① Calculated based on sample weight:L-Lactate (µmol/g) = y × Vsample ÷ (W × Vsample ÷ Vtotal) × n = y ÷ W × n② Calculated based on cell or bacterial count:L-Lactate (µmol/10⁴ cells) = y × Vsample ÷ (500 × Vsample ÷ Vtotal) × n = y ÷ 500 × n③ Calculated based on liquid volume:L-Lactate (mM) = y × Vsample ÷ Vsample × n = y × n④ Calculated based on protein concentration:L-Lactate (µmol/mg prot) = y × Vsample ÷ (Vsample × Cpr) × n = y ÷ Cpr × nParameter Description:1 mM = 1 mmol/L;Vsample : Volume of sample added, 0.05 mL;n: Sample dilution factor;Cpr: Sample protein concentration, mg/mL;W: Sample weight, g;Vtotal: Total volume of sample extract, 1 mL;500: Cell or bacterial count, 5×10⁶, converted to units of 10⁴.Result Presentation Using Previous Standard CurveTypical Standard Curve: y = 2.2613x - 0.0531Example-1: 50 µL of chicken serum was taken and processed according to the assay steps using a 96-well plate. The measured ΔAtest = Atest - Ablank= 0.435 - 0.096 = 0.339. Substituting into the standard curve, y = 0.713 mM. Calculated based on liquid volume: Lactate content (mM) = y × n = 0.713 × 5 = 3.565 mM.PrecautionsIt is recommended to perform preliminary experiments using 2-3 samples expected to have significant differences before formal testing.For tissue and cell samples, results can be normalized by measuring the protein concentration.This kit is compatible with spectrophotometer detection. Adjust the preparation volume of detection reagents proportionally according to the spectrophotometer's requirements.It is recommended to establish your own standard curve for improved accuracy. If not, you may refer to the typical standard curve formula provided in the results section for calculation.Biochemical reagents are generally irritating and biologically toxic. For your safety and health, please wear appropriate personal protective equipment (lab coat, mask, gloves, hair cap, etc.) throughout the experiment and perform experiments in a fume hood or biosafety cabinet.This product is for scientific research use only. Not intended for clinical diagnosis.Frequently Asked QuestionsWhat should I do if the sample ΔAtest is too high or too low?If the sample ΔAtest is >1.0, the lactate content in the sample is too high. Dilute the sample appropriately with Lactate Assay Buffer (multiply by the dilution factor in the calculation). If the sample ΔAtest is <0.13, increase the sample amount... Read More | Inquire | Product introduction：This kit uses an improved SDS alkaline lysis method combined with DNA preparation membrane to selectively adsorb DNA to achieve the purpose of rapid purification of plasmid DNA. It is suitable for extracting up to 500ug of high-purity plasmid DNA from 120-300ml bacterial Product introduction：This kit uses an improved SDS alkaline lysis method combined with DNA preparation membrane to selectively adsorb DNA to achieve the purpose of rapid purification of plasmid DNA. It is suitable for extracting up to 500ug of high-purity plasmid DNA from 120-300ml bacterial culture for sequencing, in vitro transcription and translation, restriction enzyme digestion, bacterial transformation and other molecular biology experiments.Scope of application：Nucleic acid extraction and purification... Read More | Product introduction：PMA qPCR live bacteria detection kit provides an effective means to detect bacterial activity. This kit provides a mixture of PMA dye and SYBR green dye based qPCR. The optimal amount of dye and the number of samples that can be processed may vary depending on the type ofProduct introduction：PMA qPCR live bacteria detection kit provides an effective means to detect bacterial activity. This kit provides a mixture of PMA dye and SYBR green dye based qPCR. The optimal amount of dye and the number of samples that can be processed may vary depending on the type of sample. PMA is a DNA binding dye with high affinity, especially with double stranded DNA. The dye itself has weak fluorescence, but it can emit brighter fluorescence after binding with nucleic acids. PMA is impermeable to the cell membrane, so it can selectively modify the DNA of dead cells with damaged membrane. After bllight (~464 nm) photolysis of PMA modified DNA, the photoreactive azido group on PMA is converted into highly reactive azene radical, which reacts with any hydrocarbon moiety near the DNA binding site to form a stable covalent nitrogen carbon bond, resulting in permanent DNA modification. This modification process will make the DNA insoluble, and it will be lost together with cell debris in the later genomic DNA extraction process. The unbound PMA remaining in the solution reacts with water molecules under strong light irradiation and decomposes into hydroxylamine compounds without cross-linking activity, so that it can no longer covalently bind DNA. Based on this characteristic of PMA, our company combines PMA and qPCR technology to form a new detection method - PMA qPCR, which is used for the screening of live bacteria. At present, the method has been validated in a variety of bacterial strains as well as yeast, fungi, viruses and parasites. The treatment of complex samples, such as feces or soil, may require optimization of sample dilution, dye concentration, and light treatment time. Treatment of diluted samples, such as water testing, may require filtration or concentration prior to dye treatment. Component： Instruction： Precautions before use：1.This live bacteria detection kit distinguishes dead bacteria and live bacteria according to cell membrane permeability. Many methods of killing bacteria cause damage to the cell membrane and are therefore compatible with this kit. But some methods, such as ultraviolet irradiation, may not immediately cause cell membrane rupture. Therefore, before selecting this kit, it is necessary to carry out literature search and pre-experiment to determine whether the kit is suitable for the bacterial type and killing method you choose. 2.After PMA treatment, the bacteria need to be photolyzed to covalently bind the dye to dead cell DNA. Photolysis operations can use blue or white light sources. Generally speaking, the brighter the lamp, the higher the efficiency of the photolysis step. Non-LED lamps ( such as halogen lamps ) may heat your sample and have a negative impact on the analysis. Ice is required to cool the sample during irradiation. 3.Sample can be cryopreservation after photolysis. Frozen samples before PMA treatment photolysis may damage the cell membrane and produce false negative results. If the sample needs to be frozen before detection, it is recommended to perform a pre-experiment first. 4.Part of the mechanism of PMA is to remove PMA covalently modified DNA from the sample by precipitation ; therefore, when extracting genomic DNA, it is necessary to use the same volume of genomic DNA eluent for volume normalization. The positive control can use the genomic DNA of living cells. 5.In order to verify the effectiveness of PMA in the test sample, the Ct ( dCt ) changes between- / + PMA can be compared. Experimental materials ( self-provided )：①Light source ( used for the photolysis step after PMA modified DNA ) ;② Bacterial genomic DNA extraction kit ; Experimental procedure： 1.Suck 10 µL of E.coli bacterial solution in liquid LB medium, and culture E.coli in the bacterial incubator overnight or longer to the logarithmic growth phase ( OD600 ≈ 1.0 ) ; Note : The culture time is adjusted according to the experiment. 2.Two portions of live E.coli, 400 µL each, were placed in a clean centrifuge tube ; 3. ( Recommended ) Preparation of dead E.coli. If the dead E.coli is needed as a control, the dead E.coli can be obtained by heating the living E.coli in a water bath at 95 °C for 5 min, or at 58 °C for 3 h. the subsequent operation of the dead E. coli is the same as that of the living E. coli ; 4.Two copies of live E.coli, one without PMA treatment, and one with 25 µM PMA treatment ( the optimal PMA concentration for treating different types or different sources of bacteria needs to be consulted in the relevant literature ) ; 5.The PMA-treated samples were placed on a shaker at room temperature and incubated in the dark for 10 min to fully mix the dye with the sample ; 6.Exposure of the sample, you can use blue or white light source, irradiation time to explore their own. For example, a 60 W blue light can be used for 15 min. Note : 1 If a halogen lamp is used, we recommend that the PMA-treated sample tube be placed on an ice block 20 cm away from the light source. Ice should be placed in a transparent tray. Adjust the light source to point directly to the sample, photolysis for 5-15 min ; if the bacteria obtained from the environment are directly used for experiments, due to the complexity or turbidity of the environmental samples, the photolysis time needs to be prolonged appropriately. 7.Treated and untreated live E.coli 5000 × g, centrifuged for 10 min, remove the supernatant ; 8.Select the appropriate genomic DNA extraction kit according to the sample type, and use the same elution volume for each group of samples when elution DNA. Note : DNA extraction steps refer to the instructions of the kit used. Part of the mechanism of action of PMA is to remove PMA-bound DNA from the sample by precipitation ; therefore, when extracting genomic DNA, each group should use the same volume of genomic DNA eluent for volume normalization ( the amount of genomic DNA extracted from dead bacteria and live bacteria is inconsistent, so the concentration of the two is significantly different ). 9.Preparation of reaction mixture according to the following system : Note : 1 For the DNA extracted by commercial DNA extraction kit, the qPCR template was optimized with 2 µL as the initial volume ; 2 The template volume should not exceed 10 % of the final reaction volume ; 3 Template concentration : gDNA as template, usually 1-10 ng ; the final concentration of PCR primers is usually 0.4µM, which can get better results. When the reaction performance is poor, the primer concentration can be adjusted in the range of 0.2-1µM. 10.Slightly vortex the reaction mixture, transfer the fixed volume to the PCR tube. 11. Test procedureNote : 1 The extension time is adjusted according to the instrument ; the Taq enzyme in mix can be activated within 2 min, but the genomic DNA may require longer denaturation time, which can be increased at this time, and the specific denaturation time can be adjusted according to the sample type. 12. ( Optional ) Data analysis Using live bacteria and dead bacteria as controls, the number of live cells in the sample was analyzed and calculated. It is recommended to verify the suitability of primers and PCR procedures before starting PMA qPCR detection of live bacteria. Calculation of dead and living bacteria control dCt ( 1 ) After the end of qPCR, the Ct value of each sample was calculated by instrument software ; ( 2 ) By calculating the dCt of each control bacteria, it was judged whether PMA successfully inhibited the amplification of dead bacterial DNA. The calculation is as follows : dCt live = Ct ( live, PMA treated ) -Ct ( live, PMA untreated ) dCt die = Ct ( die, PMA treated ) -Ct ( die, PMA untreated ) ( 3 ) The dCt expectation of living bacteria is close to 0 ± 1, which indicates that PMA does not affect the amplification of living cell DNA ; ( 4 ) The expected value of dCt of dead bacteria is greater than 4 ( dCt is 4 means that it is reduced by about 16 times, that is, 94 % of dead bacterial DNA is removed ; a dCt of 8 indicated a decrease of about 250 times, that is, 99.6 % of the dead bacterial DNA was removed ).( 5 ) The dCt of dead bacteria depends on many factors, including : strain / cell type ; the way bacteria are killed ; the concentration of PMA used ; amplified sequence length. 3. Calculation of the proportion of viable ( optional ) bacteria If the control results of dead and live bacteria are normal, the proportion of live bacteria in the sample can be calculated.( 1 ) Calculate the dCt value of the sample : dCt sample = Ct ( sample, PMA treated ) -Ct ( sample, PMA untreated ) ( 2 ) Conversion of dCt value to live bacteria ratio : PMA inhibition multiple = 2 ( sample dCt ) Viable bacteria % = 100 / PMA inhibition multiple 14. ( Optional ) Calculate the absolute number of live bacteria If you want to calculate the absolute number of viable bacteria in the sample, you need to use a known number of target bacteria genomic DNA to make a standard curve. It is recommended that the diluted concentrations of several groups of genomes are within the range of the qPCR analysis system. ( 1 ) qPCR was performed with the appropriate genome, and the Ct value was used as the ordinate, and the number of cells was used as the abscissa. The R2 value is calculated to determine the linearity, and the slope and y-axis intercept are displayed.( 2 ) Calculate the copy number of the experimental samples : Ct = slope * cell number + y axis intercept ( y = mx + b ) Bacterial count sample = ( Ct-y axis intercept ) / slope Note : The live bacterial DNA was not lost during the purification process. Examples : Product parameters：Pma: ex = 464 nm; Ex/em = 510/610 nm (following photolysis and reaction with dna/rna)Scope of application：Live bacteria detection Matters needing attention：1.Please instantaneously centrifuge the product to the bottom of the tube before use, and then carry out subsequent experiments ; 2.the kit components contain fluorescent dyes, and attention should be paid to avoiding light during use and preservation ; 3.For your safety and health, please wear experimental clothes and disposable gloves... Read More | This reagent kit uses highly sensitive silver dye, which can be applied to protein staining of denatured and non denatured gels. It has the advantages of clear target bands, low background, and flexible control of operation time. In addition, this reagent kit has added a short-term sensitization This reagent kit uses highly sensitive silver dye, which can be applied to protein staining of denatured and non denatured gels. It has the advantages of clear target bands, low background, and flexible control of operation time. In addition, this reagent kit has added a short-term sensitization step, which can significantly reduce the background and enhance the brightness of the target band. P665901Component20 TStorageP665901ASilver Stain Sensitizer (500×)2×1 mLRTP665901BSilver Stain Enhancer3 mLRTP665901CSilver Stain2×250 mLRTP665901DSilver Stain Developer4×125 mLRT Matters needing attention1. Please prepare 50 ml of fixed solution (ultrapure water: ethanol: acetic acid=6:3:1), 50 ml of eluent (10% ethanol), and 50 ml of termination solution (5% acetic acid) in advance.2. Please use deionized water and clean glass or plastic containers during operation, and wear disposable gloves for operation.The entire silver dyeing process needs to be carried out on a shaker, with a rotation speed of about 60 rpm.4. Self prepared ethanol and glacial acetic acid are required.Instructions for useThe dosage of each solution in the following operation steps takes the gel with a size of 8.5 × 5.5 cm and a thickness of 1.0 mm as an example. The gel is immersed in the solution completely, and is operated on a shaker, with a general dosage of 25 ml. For large gel, the dosage of each solution should be scaled up according to the gel volume. Please prepare 50 ml of fixed solution (ultrapure water: ethanol: glacial acetic acid=6:3:1), 50 ml of eluent (10% ethanol), and 50 ml of termination solution (5% glacial acetic acid) in advance.1. Water washing: After electrophoresis is completed, wash the gel twice with ultrapure water for 5 minutes each time.2. Fixation: Fix the gel twice with 25 ml of fixative solution for 15 minutes each time.3. Elution: Wash the adhesive twice with eluent, each time for 5 minutes.4. Water washing: Wash the glue twice with ultrapure water, each time for 5 minutes.5. Sensitization: put the gel washed in the previous step into the silver dye sensitization working solution, incubate it accurately for 1 minute at room temperature, and then wash it with ultrapure water for three times, each time for 20 seconds. Preparation of silver staining sensitization working solution: Take 50 µ l Silver Stain Sensitivity (500 x) and add it to 25 ml of ultrapure water, mix well.6. Silver staining: discard ultrapure water and incubate gel in silver staining working solution for 30 minutes. Preparation of silver staining working solution: Take 25ml Silver Stain and add 50 µ l Silver Stain Enhanced to mix well.7. Water washing: Quickly wash the glue twice with ultrapure water, with each washing accurately controlled for 20 seconds.8. Development: Immerse the washed gel in the developer immediately and incubate it at room temperature for 2-3 minutes until the protein strip is clear. Preparation of developer: Take 25ml Silver Stain Developer and add 30 µ l Silver Stain Enhanced to mix well. Attention: Within 30 seconds of development, protein bands begin to appear and continue to develop for 2-3 minutes. If the protein band appears lighter, the development time can be appropriately extended to 5 minutes or more.9. Termination: After washing the developer on the gel with the termination solution, soak the gel in a new termination solution to react for 10 minutes.Experimental imagesSilver staining results of BSA protein samples after 10% SDS-PAGE gel electrophoresisThe molecular weight of BSA protein is about 66 kD, and the loading amounts from left to right are 50 ng, 10 ng, and 5 ng, respectively... Read More |