| Description | Product DescriptionAcetyl esterase (sialate-O-acetylesterase) is a recombinant protein from Tannerella forsythia, ATCC 43037 strain, expressed in Escherichia coli. The enzyme removes acetyl groups attached via an O- group, mainly 9-, 8- and 7-. It can be used for monitoring of diacetylation of Product DescriptionAcetyl esterase (sialate-O-acetylesterase) is a recombinant protein from Tannerella forsythia, ATCC 43037 strain, expressed in Escherichia coli. The enzyme removes acetyl groups attached via an O- group, mainly 9-, 8- and 7-. It can be used for monitoring of diacetylation of sialic acids on products such as erythropoietin (EPO).The Zyme Acetyl Esterase Kit removes 9-, 8- and 7-O-acetyl groups from released sialic acids, released glycans or glycoproteins. It is commonly used for the characterization of highly-sialylated biotherapeutics such as EPO, FSH and blood clotting factors.Molecular Weight76.3 kDContentsAcetyl esterase – PBS pH7.5 buffer containing 10 mM Tris-HClReaction Buffer – 500 mM sodium acetate pH5.5Number of SamplesSufficient for up to 50 samples.Amount of SampleUp to 10 µg glycoprotein, up to 2.5 µg released glycans and up to 1 µg free sialic acid per digestion.Suitable SamplesAcetyl esterase (sialate-O-acetylesterase) can act upon complex glycoprotein samples, such as erythropoietin (EPO), bovine submaxillary mucin and oral epithelial cell-bound glycans, and on N- and O-glycans released from a glycoprotein. Either fluorescently labelled or unlabelled glycans are suitable. It can also be used on released sialic acids.Unit DefinitionOne unit (U) of acetyl esterase is defined as the amount of enzyme required to produce 300 µmole of 4-nitrophenol and acetate in 1 minute at 30°C in a buffer containing 50 mM Tris-HCl, 140 mM NaCl, pH 8.5, from 4-nitrophenyl acetate, a chromogenic esterase substrateStorageProtect from sources of heat and light. When stored correctly, the enzyme should be stable for 24 months from date of purchase. Exposure to ambient temperatures (20 – 26°C) over 3 days does not result in a reduction of enzymatic activity.ShippingThe product should be shipped at 4°C.HandlingEnsure that any glass, plastic ware or solvents used with this item are free of environmental carbohydrates. Use powder-free gloves for all sample handling procedures and avoid contamination with environmental carbohydrate.SafetyPlease read the Safety Data Sheets (SDSs) for all chemicals used. All processes involving labelling reagents should be performed using appropriate personal safety protection – safety glasses, chemically resistant gloves (e.g. nitrile), lab coat, and when appropriate, in a laboratory fume cupboard.For research use only. Not for human or drug use ApplicationAcetyl esterase (sialate-O-acetylesterase) can be used to remove 9-, 8- and 7-O-acetyl groups from released sialic acids, released glycans or glycoproteins... Read More | Annexin V ( annexin-V ) is a Ca2 + dependent phospholipid binding protein with a molecular weight of 35-36 KD, which can selectively bind to phosphatidylserine ( PS ). Phosphatidylserine ( PS ) is mainly distributed in the inner side of the cell membrane, that is, the side adjacent to the cytoplasm.Annexin V ( annexin-V ) is a Ca2 + dependent phospholipid binding protein with a molecular weight of 35-36 KD, which can selectively bind to phosphatidylserine ( PS ). Phosphatidylserine ( PS ) is mainly distributed in the inner side of the cell membrane, that is, the side adjacent to the cytoplasm. In the early stage of apoptosis, different types of cells will turn phosphatidylserine out to the cell surface and expose to the extracellular environment. At this time, using Annexin V labeled with fluorescent protein PE, that is, Annexin V-PE, combined with phosphatidylserine ( PS ), the eversion of phosphatidylserine, an important feature of apoptosis, can be directly detected by flow cytometry. Normal cells will not be stained by Annexin V-PE, apoptotic or necrotic cells will be stained by Annexin V-PE. Annexin V-PE can be used in combination with partially non-permeable nuclear dye ( 7-AAD / PI ) to distinguish cells at different stages of apoptosis. RedNucleus II provided in this kit is a far-red dye that belongs to an anthraquinone compound and cannot penetrate the intact cell membrane of living cells and early apoptotic cells. It is non-permeable, but can quickly stain the nucleus / dsDNA in dead and permeable cells. RedNucleus II is an ideal substitute for propidium iodide ( PI ) and 7-AAD.Combined with Annexin V-PE, it has better spectral characteristics without compensation regulation : it is not excited by ultraviolet light and does not overlap with PE / PE homologues, so it can be combined with FITC, PE and purple fluorescent dyes for multicolor analysis. When combined with Annexin V-PE, RedNucleus II was excluded from living cells and early apoptotic cells, while late apoptotic cells and dead cells were double-positive for Annexin V-PE and RedNucleus II. Annexin V-PE / RedNucleus II apoptosis detection kit can be detected by flow cytometry or other fluorescence detection equipment. Components: Components A598354(10T) A598354(50T) A598354(100T) A. 1×Annexin V Combining buffer solution 10 mL 50 mL 50 mL×2 B. Annexin V-PE 50 µL 250 µL 500 µL C. RedNucleus II 100 µL 500 µL 1 mLProduct parameters：Annexin v-pe:ex/em=488/578 nmrednucleus ii:ex/em=635/695 NMUsage method:1. Experimental design: Blank tube: Negative control group cells, without Annexin V-PE/RedNucleus II. Used to regulate voltage.Single staining tube: Positive control group cells were treated with Annexin V-PE alone/RedNucleus II alone. Used for adjusting compensation.Detection tube: Add Annexin V-PE/RedNucleus II to the processed cells. After adjusting the voltage compensation using blank tubes and single dye tubes, obtain the required flow data.2. Collect cells(1) For suspended cells:a. After inducing cell apoptosis, centrifuge at 1000 rpm for 5 minutes, discard the supernatant, collect the cells, gently resuspend the cells in PBS, and count them.Note: PBS resuspension cannot be omitted. The process of PBS resuspension also serves to wash cells, ensuring the subsequent binding of Annexin V-PE.b. Take 5 × 104-1 × 105 resuspended cells, centrifuge at 1000 rpm for 5 minutes, discard the supernatant, and add 100 µ L of 1 × Annexin V binding buffer to gently resuspend the cells. c. Add 5 µ L Annexin V-PE and mix gently.d. Add 5 µ L of RedNucleus II staining solution and mix gently.e. Incubate at room temperature (20-25 º C) in the dark for 15 minutes. Aluminum foil can be used to avoid light. During the incubation process, cells can be resuspended 2-3 times to improve staining efficiency.(2) For adherent cells:a. Suck out the cell culture medium into a suitable centrifuge tube, wash the adherent cells with PBS once, and add an appropriate amount of trypsin cell digestion solution (without EDTA) to digest the cells. Incubate at room temperature until gently blowing can remove the trypsin cell digestion solution when the adherent cells are blown down. Overdigestion of pancreatic enzymes should be avoided.Note: For adherent cells, the trypsin digestion step is crucial. If the trypsin digestion time is too short, cells need to be blown hard to detach, which can easily cause damage to the cell membrane and lead to false positives of cell necrosis; If the digestion time is too long, it can also cause cell membrane damage and false positives of cell necrosis, and even affect the binding of phosphatidylserine and Annexin V-PE on the cell membrane, thereby interfering with the detection of cell apoptosis.b. Add the cell culture medium collected in the previous step, gently blow down the cells, transfer them to a centrifuge tube, centrifuge at 1000 rpm for 5 minutes, discard the supernatant, collect the cells, gently resuspend the cells in PBS and count them.Note: Adding the cell culture medium from the previous step is very important. On the one hand, it can collect cells that have already been suspended and undergone apoptosis or necrosis. On the other hand, the serum in the cell culture medium can effectively inhibit or neutralize residual trypsin. The residual trypsin will digest and degrade the subsequently added Annexin V-PE, leading to staining failure.c. Take 5 × 104-1 × 105 resuspended cells, centrifuge at 1000 rpm for 5 minutes, discard the supernatant, and add 100 µ L of 1 × Annexin V binding buffer to gently resuspend the cells. d. Add 5 µ L Annexin V-PE and mix gently.e. Add 5 µ L of RedNucleus II staining solution and mix gently.f. Incubate at room temperature (20-25 º C) in the dark for 15 minutes. Aluminum foil can be used to avoid light. During the incubation process, cells can be resuspended 2-3 times to improve staining efficiency.3. Result analysis:(1) Flow cytometry detection:a. After incubation, 400 µ L of 1 × Annexin V binding buffer can be directly added to resuspend the cells, and immediately detected on the machine. Annexin V-PE is excited by 488 nm/566 nm laser, and the fluorescence emission spectrum is detected at 578 nm (BL2 (FL2)/YL1 channel), while the RedNucleus II channel emission spectrum is approximately at 695 nm (RL1 (FL4) channel).b. On the scatter plot of the bivariate flow cytometer, live cells are shown in the lower left quadrant, which is (Annexin V-PE -/RedNucleus II -); The lower right quadrant represents early apoptotic cells, which are (Annexin V-PE+/RedNucleus II -); The upper right quadrant represents necrotic and late stage apoptotic cells, which are (Annexin V-PE+/RedNucleus II+); The upper left quadrant displays naked nuclear cells, which are (Annexin V-PE -/RedNucleus II+).(2) Fluorescence microscopy detection:a. Centrifuge at 1000 rpm for 5 minutes, collect cells, and gently resuspend them in 400 µ L of 1 × Annexin V binding buffer. Transfer the cells to a 96 well plate and settle for a moment or perform cell smear, then observe under a fluorescence microscope.b. Annexin V-PE is compatible with PE filters. RedNucleus II can use a far red long pass filter.Matters needing attention：1. please centrifuge the product to the bottom of the tube immediately before use, and then conduct subsequent experiments. 2. to reduce the process of apoptosis, the incubation process can be operated on ice, but the incubation time should be extended to at least 30 min. 3. as apoptosis is a rapid process, it is recommended that samples be analyzed within 1 h after staining. 4. for adherent cells, digestion is a key step. If there are floating cells when adherent cells induce apoptosis, the floating cells and adherent cells should be collected and stained. Handle adherent cells with care to avoid artificial damage to cells. The trypsin digestion time is too short, and the cells need to be blown hard to fall off, which is easy to cause damage to the cell membrane and excessive intake of rednucleus II; If the digestion time is too long, the cell membrane is also prone to damage, and even affect the binding of phosphatidylserine and annexin v-pe on the cell membrane. When digesting, spread pancreatin on the bottom of the well plate, fully contact the pancreatin with the cells when shaking gently, then pour out most of the pancreatin, use the remaining small amount of pancreatin to digest for a period of time, and terminate when the gap between cells increases and the bottom of the bottle is spotted. Try not to use EDTA in the digestive juice, which will affect the binding of annexin V to PS. 5. after the adherent cells are digested with trypsin, it is recommended to stain after recovering in the optimal culture conditions and medium for about 30 min to avoid false positives. 6. in order to avoid losing cells when washing cells, you can use a large tip over a small tip to aspirate. 7. the optimal concentration of dye is determined by the specific experimental requirements. 8. fluorescent dyes have quenching problems. Please try to avoid light during storage and use to slow down fluorescence quenching. 9. for your safety and health, please wear experimental clothes and disposable gloves.Scope of application：Early apoptosis detection, annexin V Kit... 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 | DescriptionThe Baran Late-Stage Toolkit is a convenient collection of 12 highly innovative reagents that are highly effective in the diversification of complex molecules. The contents in the box are 11 Baran Diversinates™and one vial of Palau′Chlor®in amounts of 100 mg each. For DescriptionThe Baran Late-Stage Toolkit is a convenient collection of 12 highly innovative reagents that are highly effective in the diversification of complex molecules. The contents in the box are 11 Baran Diversinates™and one vial of Palau′Chlor®in amounts of 100 mg each. For obtaining larger amounts of any desired kit component, see the kit component table at the bottom of the page.Useful Topics:Late Stage FunctionalizationBaran Group – Professor Product PortalPalau′ChlorDiversinates... 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 |