| 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 | Inquire | This reagent kit is for research purposes only. Purpose of use: This reagent kit is used to determine the content of lactose in serum, plasma, and related liquid samples.Experimental principle:This kit applies enzyme-linked immunosorbent assay to determine the level of lactose in the sample. This reagent kit is for research purposes only. Purpose of use: This reagent kit is used to determine the content of lactose in serum, plasma, and related liquid samples.Experimental principle:This kit applies enzyme-linked immunosorbent assay to determine the level of lactose in the sample. Purified lactose antibodies were coated on a microplate to produce solid-phase antibodies. Lactose was added to the microplate of the coated monoclonal antibody, along with HRP labeled lactose antigens, to compete for binding. After thorough washing, the substrate TMB was added for colorimetry. The depth of sample color is negatively correlated with the content of lactose in the sample. Measure the absorbance (OD value) at a wavelength of 450nm using an enzyme-linked immunosorbent assay (ELISA) reader, and calculate the content of lactose in the sample through a standard curve.Kit composition:130times concentrated washing solution20ml×1 bottle8.1Standard S1（80µg/L）0.5ml×1bottle2Enzyme-linked immunosorbent assay6ml×1 bottle8.2Standard S2（40µg/L）0.5ml×1bottle3Enzyme labeling coated plate96 holes x 1 pieces8.3Standard S3（20µg/L）0.5ml×1bottle4Color reagent A solution6ml×1 bottle8.4Standard S4（10µg/L）0.5ml×1bottle5Color developer B solution6ml×1 bottle8.5Standard S5（5µg/L）0.5ml×1bottle6Stop solution6ml×1 bottle9Instructions1 copy7Sample Diluent6ml×1 bottle10Microplate Sealers2 sheetsSpecimen requirements:1. Specimen processing:(1) After collecting the water sample, it is repeatedly freeze-thawed three times at -20 ℃, and then filtered through glass fiber for future reference(2) The tissue samples should be extracted using butanol: methanol: water (5:25:70 V: V: V), or extracted according to relevant literature. The experiment should be conducted as soon as possible after extraction. If the experiment cannot be conducted immediately, the specimen can be stored at -20 ℃ for future reference2. Samples containing NaN3 cannot be detected as NaN3 inhibits the activity of horseradish peroxidase (HRP).Operation steps:1. Sample addition: Set up standard wells, blank wells (blank control wells do not include samples and enzyme-linked immunosorbent assay reagents, the other steps are the same), and sample wells to be tested. Add 50 microliters to the standard well on the enzyme-linked immunosorbent assay (ELISA) plate, and first add 40 diluents to the sample well to be tested µ l. Then add 10 more samples to be tested µ L (The final dilution of the sample is 5 times). Add the sample to the bottom of the enzyme-linked immunosorbent assay (ELISA) plate well, avoiding touching the well wall as much as possible. Gently shake and mix well.2. Enzyme addition: Add 50 enzyme labeled reagents to each well µ l. Excluding blank holes.3. Warm incubation: Seal the plate with a sealing film and incubate at 37 ℃ for 60 minutes.4. Solution preparation: Dilute 30 times the concentrated washing solution with distilled water and set aside for later use5. Washing: Carefully remove the sealing film, discard the liquid, shake dry, fill each well with washing solution, let it stand for 30 seconds, then discard. Repeat this process 5 times and pat dry.6. Color development: Add color development agent A50 to each well first µ l. Add color developer B50 again µ l. Gently shake and mix well, and develop color at 37 ℃ in the dark for 15 minutes7. Termination: Add 50% termination fluid to each hole µ l. Terminate the reaction (at this point, the blue color immediately turns yellow).8. Measurement: Zero the blank hole and sequentially measure the absorbance (OD value) of each hole at a wavelength of 450nm. The measurement should be conducted within 15 minutes after adding the termination solution.Calculation:Draw a standard curve on a coordinate paper with the concentration of the standard substance as the x-axis and the OD value as the y-axis. Based on the OD value of the sample, determine the corresponding concentration from the standard curve; Multiply it by the dilution factor; Alternatively, a linear regression equation can be used to calculate the standard curve using the concentration and OD value of the standard substance. The OD value of the sample can be substituted into the equation to calculate the sample concentration, which is then multiplied by the dilution factor to obtain the actual concentration of the sample.Notes:1. The kit should be balanced at room temperature for 15-30 minutes before use when taken out from the cold storage environment. If the enzyme coated plate is not used up after opening, the Flat noodles should be stored in a sealed bag.2. Concentrated detergent may precipitate crystals. When diluted, it can be heated in a water bath to aid in dissolution. Washing does not affect the results.3. A sampler should be used for each step of sample addition, and its accuracy should be regularly calibrated to avoid experimental errors. It is best to control the sample addition time within 5 minutes. If there are a large number of specimens, it is recommended to use a firing gun for sample addition.4. Please make a standard curve at the same time as each measurement, preferably with a re hole. If the content of the substance to be tested in the sample is too high (the OD value of the sample is greater than the OD value of the first well of the standard well), please dilute the sample diluent by a certain multiple (n times) before measurement. When calculating, please multiply the total dilution multiple (x n x 5).5. The sealing film is only for one-time use to avoid cross contamination.6. Please store the substrate in dark.7. Strictly follow the instructions and determine the test results based on the reading of the enzyme-linked immunosorbent assay (ELISA) reader8. All samples, washing liquids, and various waste should be treated as infectious substances.9. The components of this reagent with different batch numbers shall not be mixed.Detection range:two µ G/L-90 µ G/L... Read More | Inquire | The Succinic Acid (Succinate) assay kit is suitable for the specific assay of succinic acid in wine, cheese, eggs, sauce and other food products. Succinic acid (or succinate) is found in all plant and animal materials as a result of the central metabolic role played by this dicarboxylic acid in the The Succinic Acid (Succinate) assay kit is suitable for the specific assay of succinic acid in wine, cheese, eggs, sauce and other food products. Succinic acid (or succinate) is found in all plant and animal materials as a result of the central metabolic role played by this dicarboxylic acid in the Citric Acid Cycle. Succinic acid concentrations are monitored in the manufacture of numerous foodstuffs and beverages, including wine, soy sauce, soy bean flour, fruit juice and dairy products (e.g. cheese).Product Description： Succinic acid is found in all plant and animal materials as a result of the central metabolic role played by this dicarboxylic acid in the Citric Acid Cycle. Succinic acid concentrations are monitored in the manufacture of numerous foodstuffs and beverages, including wine, soy sauce, soy bean flour, fruit juice and dairy products (e.g. cheese). The ripening process of apples can be followed by monitoring the falling levels of succinic acid. The occurrence of > 5 mg/kg of this acid in egg and egg products is indicative of microbial contamination. Apart from use as a flavouring agent in the food and beverage industries, succinic acid finds many other non-food applications, such as in the production of dyes, drugs, perfumes, lacquers, photographic chemicals and coolants. Preparation Instructions：Suitable for succinate determination in food, beverage, agricultural products, and other biological samples.Note for Content：The number of manual tests per kit can be doubled if all volumes are halved. This can be readily accommodated using the MegaQuantTM Wave Spectrophotometer (D-MQWAVE).Browse all of our organic acid assay kits.Principle：The Succinate Assay Kit provides a simple, one step assay for measuring succinate. In this assay succinate is converted to pyruvate which reacts with specific reagents and dye to form a colored product. The color intensity at 570 nm or fluorescencAdvantages：Extended cofactors stability. Dissolved cofactors stable for > 1 year at 4oC.Very competitive price (cost per test)All reagents stable for > 2 years as suppliedVery rapid reaction (even at room temperature)Mega-Calc™ software tool is available from our website for hassle-free raw data processingStandard includedSuitable for manual, microplate and auto-analyser formats... 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