| Description | Inquire | The bacterial viability / toxicity detection kit contains two fluorescent dyes. Nucgreen is a green nucleic acid dye that can stain live and dead bacteria; Ethd III is a red nucleic acid dye that only stains dead bacteria with damaged cell membranes. When nucgreen and ethd III are properly mixed, The bacterial viability / toxicity detection kit contains two fluorescent dyes. Nucgreen is a green nucleic acid dye that can stain live and dead bacteria; Ethd III is a red nucleic acid dye that only stains dead bacteria with damaged cell membranes. When nucgreen and ethd III are properly mixed, the bacteria with intact cell membrane appear green, while the bacteria with damaged cell membrane can appear green and red under different channels, respectively. A common criterion for bacterial viability is the ability to propagate in a suitable nutrient medium, known as a growth assay. This kit is generally in good agreement with the growth assay results in liquid or solid medium. However, under certain conditions, membrane damaged bacteria may recover and propagate in nutrient medium, and such bacteria will be identified as dead bacteria in this assay. On the contrary, some bacteria with intact membranes may not be able to propagate in nutrient medium, but will be recognized as viable bacteria in this assay. Therefore, if there is a large difference between the test results of this kit and the bacterial growth assay, the above possibilities should be considered. Component： Product parameters： NucGreen: Ex/Em = 503/530 nm (结合 DNA)；EthD-III: Ex/Em = 530/620 nm (结合 DNA)。Usage:1 Preparation of control samples for live and dead bacteria (optional)1. Cultivate 4 mL of bacteria in liquid medium until late logarithmic phase.2. Prepare two 1 mL bacterial solutions in an EP tube and centrifuge for 10-15 minutes under 5000-10000 g conditions.3. Remove the supernatant and add 0.3 mL of 0.85% NaCl resuspended bacteria to one of the EP tubes, and 1 mL of 0.85% NaCl resuspended bacteria to the other tube.4. Add 0.7 mL of isopropanol to a tube containing 0.3 mL of 0.85% NaCl, and mix thoroughly (with a final concentration of 70% isopropanol) to prepare a dead bacterial sample.5. Incubate the two samples at room temperature for 1 hour and mix every 15 minutes.6. Centrifuge the two samples at 5000-10000 g for 10-15 minutes.7. Remove the supernatant, add 1 mL of 0.85% NaCl to resuspend the bacteria in both samples, and centrifuge again as in step 6.8. Use a spectrophotometer to measure the absorbance values (OD670) of two bacterial suspensions at 670 nm.9. Adjust the density of the two bacterial suspensions (live and dead) to 108 bacteria/mL (OD670 ≈ 0.3), and then dilute with 0.85% NaCl at 1:100 to achieve a final density of 106 bacteria/mL.10. Mix two bacterial suspensions as shown in the table below to obtain the required live cell ratio: dead cell ratio.Table 1 Mix live and dead bacterial suspensions by a certain volume to achieve the required ratio of live and dead cellsLive cells: Dead cellsVolume of viable bacterial suspension（mL）Volume of dead bacterial suspension（mL）0:10001.010:900.10.920:800.20.830:700.30.750:500.50.5100:01.00II Staining methods for fluorescence microscopy observation1. Mix 1 volume of component A, NucGreen, and 2 volumes of component B, EthD-III, in a microcentrifuge tube. After thorough mixing, add 8 volumes of 0.85% NaCl solution to obtain a 100 x dye solution.2. Every 100 µ L bacterial suspension, add 1 µ 100 x dye solution of L.3. Mix thoroughly and incubate at room temperature in the dark for 15 minutes.4. Take 5 µ The bacterial suspension after L staining was dropped onto a glass slide with an 18 mm square cover glass.5. Observe under a fluorescence microscope. The fluorescence of live and dead bacteria can be observed simultaneously under any standard FITC long-acting filter. Alternatively, live (green fluorescent) and dead (red fluorescent) bacteria can be observed using FITC and Cy3 (or Texas Red) channels, respectively.Attention: (1) Before staining bacteria, attention must be paid to removing residues of growth media. Nucleic acid and other media components can bind to NucGreen and EthD-III dyes in some way, resulting in unacceptable staining changes. A simple washing step is usually sufficient to remove interfering media components from bacterial suspension. It is not recommended to use phosphate buffer solutions as they can reduce staining efficiency. (2) Before starting the formal experiment, the dye concentration should be adjusted to distinguish between NucGreen labeling live bacteria and EthD-III labeling dead bacteria. The optimal concentration may vary depending on the bacterial strain. It is generally best to use the lowest dye concentration that can provide sufficient signal. The above conditions have been optimized for staining live/dead cells of Escherichia coli.III Before starting the staining method experiment of flow cytometry, please read the precautions under the fluorescence microscope staining steps.According to Table 1, add 11 different proportions of live and dead bacteria to the EP tube. Each of the 11 samples has a volume of 1 mL.2. Add 12 µ The A component of L, NucGreen, and 24 µ The B component EthD-III of L was mixed in a microcentrifuge tube. Add 3 to each of the 11 samples µ Mix the mixed dyes of L thoroughly by blowing them up and down several times. (Note: Additional control bacterial samples need to be prepared for separate NucGreen and EthD-III staining)3. Incubate at room temperature in the dark for 15 minutes.4. Analyze each sample using a flow cytometer, detect NucGreen positive cells using FITC channels, and detect EthD-III positive cells using PI or PE channels.Matters needing attention：1. please centrifuge the product to the bottom of the tube immediately before use, and then conduct subsequent experiments. 2. if the orifice plate is used for detection, a small amount of bacterial liquid can be left for imaging after standing for 10 min, which can effectively reduce the background. 3. in order to be closer to the real results, it is recommended to keep the brightness of red fluorescence consistent with that of green fluorescence in merge pictures. 4. fluorescent dyes have quenching problems. Please try to avoid light during experimental operation to slow down fluorescence quenching. 5. for your safety and health, please wear experimental clothes and disposable gloves.Scope of application：Staining of dead and live bacteria... Read More | Inquire | Product content C665709Component50 TStorageC665709ABuffer CL45 mLRTC665709BBuffer CB (concentrate)60 mLRTC665709CBuffer GW1 (concentrate)13 mLRTC665709DBuffer GW2 (concentrate)15 mLRTC665709EBuffer EBL10 mLRTC665709FProteinase K100 mgRTC665709GProteinase K Storage Buffer5 mLRTC665709HSpin Columns DFProduct content C665709Component50 TStorageC665709ABuffer CL45 mLRTC665709BBuffer CB (concentrate)60 mLRTC665709CBuffer GW1 (concentrate)13 mLRTC665709DBuffer GW2 (concentrate)15 mLRTC665709EBuffer EBL10 mLRTC665709FProteinase K100 mgRTC665709GProteinase K Storage Buffer5 mLRTC665709HSpin Columns DF with Collection Tubes50 EA2-8℃C665709ICentrifuge Tubes (L-1.5 mL)50 EART Product IntroductionThis kit is suitable for the extraction of free DNA from fresh or frozen serum, plasma, lymph fluid and other cell-free body fluids.This kit adopts centrifugal adsorption columns that can specifically bind nucleic acids and a unique buffer system.After the sample is lysed, the free DNA binds to the silica gel membrane under high salt conditions, and the free DNA elutes from the silica gel membrane at low salt and high pH. The product can handle liquid samples of 0.1-1 ml, and the elution volume of the configured high-efficiency micro adsorption column can be as low as 20 µl. The purified DNA is of high yield and quality, with maximum removal of proteins, pigments, lipids, and other inhibitors, and the rate of free DNA yield is highly dependent on the type of samples, storage conditions, time, and inter-individual variations. The quality of free DNA obtained from purification is stable and reliable, and can be directly used in molecular biology experiments such as PCR, fluorescence quantitative PCR and second generation sequencing.Self-contained reagents: anhydrous ethanol, isopropanol.Pre-experiment Preparation and Important NotesAdd 5 ml of 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.Repeated freezing and thawing of the sample should be avoided, as this can lead to a decrease in extraction.This kit can extract 0.1-1 ml of liquid samples.Before use, please check Buffer CL, Buffer CB for crystallization or precipitation, if there is any crystallization or precipitation, please re-dissolve Buffer CL, Buffer CB by incubation at 56℃ in a water bath.Before first use isopropyl alcohol should be added to Buffer CB according to the instructions on the reagent bottle label, mixed well, and labeled on the reagent bottle label.Before the first use, anhydrous ethanol should be added to Buffer GW1 and Buffer GW2 according to the instructions on the label of the reagent bottle, mixed well, and labeled on the label of the reagent bottle.Preheat the water bath to 60°C before starting the experiment.The elution buffer Buffer EBL can be preheated to 60°C and used.Operation stepsAdd 20 µl of Proteinase K to the centrifuge tube (supplied).Add 200 µl of serum/plasma sample.Note: When the sample volume exceeds 200 µl, please increase the amount of Proteinase K, Buffer CL and Buffer CB reagents in equal proportions, and the specific amount of reagents added can be referred to the attached table.3. Add 160 µl Buffer CL, mix upside down and shake vigorously for at least 30 seconds.4. Incubate at 60°C for 30 minutes, during which time mixing was inverted several times.Note: Incubation of 200µl serum/plasma samples at 60°C for 10-15 minutes is sufficient.Add 360 µl of Buffer CB (check for addition of isopropanol before use) and shake until thoroughly mixed.Ice bath for 5 minutes and centrifuge briefly to concentrate the liquid on the walls and wall caps to the bottom of the tube.Add all of the solution obtained in step 6 to the adsorption columns (Spin Columns DF) that have been loaded into the collection tubes, and if the solution cannot be added all at once, it can be transferred in several times. centrifuge the columns at 12,000 rpm for 1 minute, pour off the waste solution from the collection tubes, and put the columns back into the collection tubes.Add 500µl of Buffer GW1 to the adsorbent column (check that anhydrous ethanol is added before use),centrifuge the column at 12,000rpm for 30 seconds, pour off the waste liquid in the collection tube, and put the adsorbent column back into the collection tube.Add 750 µl Buffer GW2 to the adsorbent column (check that anhydrous ethanol is added before use), centrifuge at 12,000 rpm for 30 seconds, pour off the waste liquid in the collection tube, and put the adsorbent column back into the collection tube.10. Add 750 µl of anhydrous ethanol to the adsorbent column and centrifuge at 12,000 rpm for 30 s. Pour off the waste liquid in the collection tube and put the adsorbent column back into the collection tube.11. 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, which can interfere with the subsequent enzymatic reaction.12. Place the adsorption column in a new centrifuge tube, add 20-100 µl Buffer EBL or sterilized water to the middle part of the adsorption column overhanging the column, leave it 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, you can use sterilized water for elution. The pH value of the eluent has a great influence on the elution efficiency, if water is used as the eluent should ensure that its pH value is 7.0-8.5 (you can use NaOH to adjust the pH value of water to this range), and the elution efficiency is not high when the pH value is lower than 7.0.2) Preheat the elution buffer BufferEBL to 60℃ and use it, and incubate it at room temperature for 5 minutes before centrifugation to increase the yield.3) If the final concentration of DNA is to be increased, the resulting solution can be reintroduced into the adsorption column and left at room temperature for 2-5 minutes and centrifuged at 12,000 rpm for 1 minute.4) Because DNA preserved in water will be affected by acidic hydrolysis, for long-term storage, it is recommended to elute it with Buffer EBL and store it at -20℃.Table: Recommended reagent additions for different sample sizes... Read More | Inquire |