| Description | 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 | The content of this cell is too long for an XLSX file (more than 32767 characters). Please use the CSV format for this export | DescriptionCobalt is a transition metal that serves as a trace dietary mineral for all multicellular organisms. Cobalt is an important cofactor for the Vitamin B12class of compounds where it occupies the center of the vitamin B12corrin ring. Cobalt can also be coordinated in the active site of the DescriptionCobalt is a transition metal that serves as a trace dietary mineral for all multicellular organisms. Cobalt is an important cofactor for the Vitamin B12class of compounds where it occupies the center of the vitamin B12corrin ring. Cobalt can also be coordinated in the active site of the non-corrin containing metalloenzyme methionine aminopeptidase.Suitability: Suitable for quantitating cobalt concentrations in a variety of samplesPrinciple: The Cobalt Assay kit provides a simple and direct procedure for measuring cobalt in a variety of samples. In this assay, cobalt reacts with 2-mercaptoethanol under basic conditions to form a complex with a strong absorbance at 475 nm. Interference from the metal ions Fe2+, Cu2+, Ni2+, Zn2+, and Mn2+is <10% at this wavelength. This assay gives a linear range of 10-50 nmoles of cobalt.}Preparation instructionsSuitable for quantitating cobalt concentrations in a variety of samplesPrincipleThe Cobalt Assay kit provides a simple and direct procedure for measuring cobalt in a variety of samples. In this assay, cobalt reacts with 2-mercaptoethanol under basic conditions to form a complex with a strong absorbance at 475 nm. Interference... Read More | D665729 Component 50 T Storage D665729A Conversion Buffer CR 5×1 mL RT D665729B Buffer CL 30 mL RT D665729C Buffer MD 0.4 mL RT D665729D Buffer DB 10 mL RT D665729E Buffer WB (concentrate) 10 mL RT D665729F Buffer GW1 (concentrate) 13 mL RT D665729G Buffer GW2 (concentrate) 15 mL RT D665729H D665729 Component 50 T Storage D665729A Conversion Buffer CR 5×1 mL RT D665729B Buffer CL 30 mL RT D665729C Buffer MD 0.4 mL RT D665729D Buffer DB 10 mL RT D665729E Buffer WB (concentrate) 10 mL RT D665729F Buffer GW1 (concentrate) 13 mL RT D665729G Buffer GW2 (concentrate) 15 mL RT D665729H Buffer EB 4 mL RT D665729I Buffer PS 10 mL RT D665729J Spin Columns DF 50 Pcs 2-8 ℃ D665729K Collection Tubes 50 Pcs RTProduct Introduction:The basic principle of this reagent kit is that after DNA is treated with sodium bisulfite, unmethylated cytosine can be transformed into uracil, while methylated cytosine remains unchanged. And adopting an innovative high-temperature treatment method, the transformation time is greatly shortened, the transformation efficiency is improved, and the transformation efficiency can reach over 99%. At the same time, using a silicon-based membrane purification column, DNA can be recovered and purified from the methylated solution through a simple binding washing elution step. The recovered DNA has high purity and good integrity, and can be directly used for sequencing, methylated PCR detection, chip analysis, connection and transformation, enzyme digestion, labeling, microinjection, PCR and in vitro transcription and other molecular biology experiments.Self prepared reagents: anhydrous ethanol, 75% ethanol.Preparation and important precautions before the experiment1. Product usage method:(1) 10 times packaging preparation method: CT Conversion Agent is a solid mixture that must be prepared before first use. Add 2 ml sterile water and 100 µ M-Dissolving Buffer and 300 µ Add M-Diffusion Buffer to the CT Conversion Agent tube. Dissolve at 55 ° C and shake until completely dissolved. Store the CT Conversion Agent solution at room temperature (20 ° C-30 ° C) in the dark before use. The CT Conversion Agent for each tube is designed for 10 DNA treatments. In order to achieve better results, the prepared CT Conversion Agent should be used immediately. If not used immediately, the CT Conversion Agent solution can be stored at -20 ° C for 1 week. Before use, be sure to thaw the stored CT Conversion Agent solution at room temperature and mix thoroughly by shaking or inverting for 2 minutes, CT Conversion Reagent is sensitive to light, so it is important to minimize exposure to light as much as possible.(2) 50 times packaging preparation method: CT Conversion Agent and M-Dissolving Buffer are solid mixtures that must be prepared before first use. Add 5 ml of sterile water to the M-Dissolving Buffer and shake to dissolve. After all the solids have dissolved, transfer all the solution from the M-Dissolving Buffer tube to the CT Conversion Agent tube and add 5.5 ml of sterile water. Add 1.5 ml of M-Dilution Buffer to the CT Conversion Agent tube. Dissolve at 55 ° C and shake until completely dissolved. Store the CT Conversion Agent solution at room temperature (20 ° C-30 ° C) in the dark before use. The CT Conversion Agent for each tube is designed for 50 DNA treatments. In order to achieve better results, the CT Conversion Agent should be used immediately after preparation. If not immediately used, the CT Conversion Agent solution can be stored at -20 ° C for 1 week. Before use, be sure to thaw the stored CT Conversion Agent solution at room temperature and mix thoroughly by shaking or inverting for 2 minutes, CT Conversion Reagent is sensitive to light, so it is important to minimize exposure to light as much as possible.2. Before the first use, anhydrous ethanol should be added to the M-Wash Buffer according to the instructions on the reagent bottle label.Operation stepsThe range of DNA prepared each time is 1 ng-4 µ Between g, the optimal amount is 500 ng-2 µ G.1. Take 20 µ Add DNA sample into centrifuge tube (self provided), and if the sample amount is insufficient, replenish with water up to 20 µ L.2. Add 2.2 to the DNA sample µ Mix the sample well with the M-Dilution Buffer of l.3.42 ℃ water bath for 30 minutes.4. Add 220 to the sample obtained from the previous step µ Prepare the CT Conversion Agent solution, mix well, and incubate in an 80 ℃ constant temperature water bath in a dark place for 60 minutes.5. Add 480 to the solution in the previous step µ M - Buffer PA, gently mix upside down.6. Column balance: Add 200 to the spin columns DS that have been loaded into the collection tube µ Centrifuge at 12000 rpm (~13400 × g) for 2 minutes, discard the waste liquid in the collection tube, and place the adsorption column back into the collection tube.7.Add all the solution obtained from step 5 to the adsorption column (already loaded into the collection tube), let it stand at room temperature for 2 minutes, centrifuge at 12000 rpm for 1 minute, discard the waste liquid in the collection tube, and place the adsorption column back into the collection tube.Attention: The maximum capacity of the adsorption column is 750 µ l. If the sample volume is greater than 750 µ L can be added in batches.8. Add 500 to the adsorption column µ Centrifuge at 12000 rpm for 1 minute using M-Buffer PA, discard the waste liquid from the collection tube, and place the adsorption column in the recovery tube.9. Add 650 to the adsorption column µ M-Wash Buffer (please check if anhydrous ethanol has been added before use), centrifuge at 12000 rpm for 1 minute, discard the waste liquid in the collection tube, and place the adsorption column in the collection tube.10.12000 rpm for 2 minutes, discard the waste liquid, and place the adsorption column at room temperature for a few minutes to thoroughly air dry.Note: The purpose of this step is to remove residual ethanol from the adsorption column, which will affect subsequent enzymatic reactions (such as enzyme digestion, PCR, etc.).11. Place the adsorption column into a new centrifuge tube (provided by oneself), and add 20 drops to the middle position of the adsorption membrane in the air µ M-Elution Buffer (pH 8.5), leave at room temperature for 2 minutes. Collect DNA solution by centrifugation at 12000 rpm for 1 minute.12. Collect 20 µ Add 2.2 to DNA µ M-Diffusion Buffer, let it stand at room temperature for 30 minutes.13. Add 500 to the solution µ After pre cooling anhydrous ethanol, invert and mix well, and place the solution at -20 ℃ to precipitate for 30 minutes (overnight precipitation is more effective).14.12000 rpm for 15 minutes and gently discard the supernatant.15. Add 75% ethanol, centrifuge at 12000 rpm for 1 minute, pour out the supernatant, wait for ethanol to evaporate at room temperature, then add 20 µ Dissolve the M-Elution buffer and store the DNA at -20 ℃. The DNA collected in this step can be used for subsequent related experiments... Read More | Inquire |