| Description | Acridine Orange (AO) is a metachromatic fluorescent dye whose emission color varies depending on the target it binds to:When binding to double-stranded DNA: It intercalates between base pairs and emits green fluorescence upon excitation (Ex 488 nm, Em 530 nm).When binding to single-stranded RNA or Acridine Orange (AO) is a metachromatic fluorescent dye whose emission color varies depending on the target it binds to:When binding to double-stranded DNA: It intercalates between base pairs and emits green fluorescence upon excitation (Ex 488 nm, Em 530 nm).When binding to single-stranded RNA or lysosomes: It attaches via electrostatic interactions and emits orange-red fluorescence (Em 640 nm).Under a fluorescence microscope, Acridine Orange permeates the membranes of normal cells, staining the nucleus with uniform green or yellow-green fluorescence. In apoptotic cells, due to chromatin condensation and fragmentation into apoptotic bodies, AO stains them with intense, condensed yellow-green fluorescence or fragmented yellow-green particles. In necrotic cells, the yellow-green fluorescence is reduced or absent.Acridine Orange is often used in combination with Propidium Iodide (PI) for dual staining. Since PI stains only dead cells, producing orange-red fluorescence, this method allows differentiation among normal, apoptotic, and necrotic cells.ComponentsA1456513Component50 Test100 TestStorage ConditionQuantity Per TestA1456513ADilution Buffer10 mL50 mL2-8℃0.1 mL per 0.5-1.0 × 10⁶ cellsA1456513BAO Staining Solution100 µL500 µL2-8℃, Protect from light. Do not freeze1 µL per 0.5-1.0 × 10⁶ cellsNote: The recommended number of cells to stain per test is 0.5-1.0 × 10⁶ cells.Procedure1. Preparation of Acridine Orange Staining Solution b. Mix the AO Staining Solution with the Dilution Buffer at a ratio of 1:1000 to prepare the working solution. For example, add 10 µL of AO Staining Solution to 10 mL of Dilution Buffer to obtain 10 mL of Acridine Orange staining solution. 2. Staining with Acridine Orangea. For adherent cells: (a) Gently aspirate the culture medium from the plate. Rinse with PBS for about 10 seconds, then remove PBS. (b) Add Acridine Orange staining solution and incubate at room temperature for 5 minutes. Remove the staining solution and rinse with PBS for about 10 seconds. Repeat the rinse once. Note: For adherent cells cultured in a 6-well plate with a confluence exceeding 80%, it is recommended to add the staining working solution at a volume of 1 mL per well. This volume can be optimized based on the specific experimental system.(c) Incubate at room temperature for 5 minutes. (c) Add an appropriate amount of cell culture medium, staining buffer, or other suitable solution to cover the well bottom. Observe under a microscope. Depending on the detection requirements, green fluorescence can be observed at Ex/Em = 488/530 nm, and red fluorescence can be observed at Ex/Em = 540/640 nm. Alternatively, measure fluorescence intensity using a fluorescence microplate reader with bottom-reading capability.b. For suspension cells: (a) Take 1 mL of cell suspension. Centrifuge at 500g for 5 minutes at room temperature. Gently aspirate the medium, resuspend in PBS, and centrifuge again at 500g for 5 minutes. Remove PBS. (b) Add an appropriate amount of Acridine Orange staining solution to achieve a cell density of approximately 10⁶ cells/mL.(c) Incubate at room temperature for 5 minutes. (d) A drop of the sample was directly applied onto a glass slide, covered with a coverslip, and examined under a microscope. Depending on the detection requirements, green fluorescence can be observed at Ex/Em = 488/530 nm, and red fluorescence can be observed at Ex/Em = 540/640 nm. Alternatively, after staining, analyze directly by flow cytometry or measure fluorescence with a microplate reader.Note: Centrifugation to remove staining solution can reduce background fluorescence. For suspension cells or adherent cells in suspension, consider reducing the AO staining solution concentration by 2–5 times and shortening the staining time to 2 minutes.Precautions1. AO Staining Solution is toxic. Handle with care. 2. For your safety and health, wear a lab coat and disposable gloves. 3. Fluorescent dyes are susceptible to quenching. It is recommended to complete detection on the same day after staining... Read More | Inquire | Inquire | 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... 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