| Description | Product introduction：Griess reagent can be used for spectrophotometric detection of nitrite. The reagent contains two chemicals, sulfonic acid and n- (1-naphthyl) ethylenediamine. Under acidic conditions, sulfamic acid is converted into diazonium salt by nitrite, which can form a highly Product introduction：Griess reagent can be used for spectrophotometric detection of nitrite. The reagent contains two chemicals, sulfonic acid and n- (1-naphthyl) ethylenediamine. Under acidic conditions, sulfamic acid is converted into diazonium salt by nitrite, which can form a highly colored azo dye with n- (1-naphthyl) ethylenediamine. This dye can be detected at 548 nm: because no is extremely unstable, it is oxidized to form nitrite and nitrate. Griess indirectly reflects the content of no by detecting the content of nitrite.Matters needing attention：1. before using Griess reagent, return it to room temperature and check the solution for precipitation. If Griess reagent I contains sediment when taken out, it can be placed in a 37 ℃ water bath until the sediment dissolves. 2. this product is potentially harmful. Avoid prolonged or repeated exposure. Avoid entering eyes, skin or clothing. Please wear lab clothes and disposable gloves for operation.Scope of application：No detectionComponent：Instruction：1.Griess Reagent I and II were taken out to restore the room temperature.2.Standard dilution : The standard NaNO2 ( 1-100 µM ) was diluted with the solution used for the sample to be tested. The standard was diluted to 1 µM, 10 µM, 20 µM, 40 µM, 80 µM and 100 µM, and 100 µL standard was added to each well. If the sample concentration is too low, the range of the standard curve can be appropriately reduced ( 1 µM, 2 µM, 3 µM, 4 µM, 6 µM, 8 µM, 10 µM ).3.Sample detection :( 1 ) According to the total volume of 200 µL / hole, 100 µL / hole sample was added to the 96-well plate ; if the sample is the supernatant of the culture medium, it can be sampled directly, and if there is sediment, the supernatant should be taken after centrifugation. If the sample is a cell or tissue, it can be quickly lysed by freeze-thaw, and then centrifuged to obtain the supernatant. The volume of less than 100 µL can be diluted with diH2O or 0.9 % NaCl ( corresponding standards also need to be diluted with diH2O or 0.9 % NaCl ).( 2 ) According to 50 µL / hole, Griess Reagent I was added to each hole.( 3 ) According to 50 µL / hole, Griess Reagent II was added to each hole.( 4 ) The absorbance was measured at 540 nm. If there is no 540 nm filter, 520-560 nm filter can also be. If there is no microplate reader or a suitable filter, the concentration of nitric oxide in the sample can also be determined by visual colorimetry. A more precise concentration gradient is required for the standard when visual colorimetric... Read More | Alanine Aminotransferase (ALT), also known as serum glutamic-pyruvic transaminase (SGPT), is a pyridoxal-phosphate-dependent enzyme that catalyzes the reversible transfer of an amino group from alanine to α-ketoglutarate, generating pyruvate and glutamate. ALT is found primarily in liver and Alanine Aminotransferase (ALT), also known as serum glutamic-pyruvic transaminase (SGPT), is a pyridoxal-phosphate-dependent enzyme that catalyzes the reversible transfer of an amino group from alanine to α-ketoglutarate, generating pyruvate and glutamate. ALT is found primarily in liver and serum, but occurs in other tissues as well. Hepatocellular injury often results in an increase of serum ALT levels and serum ALT levels can be used as a marker for liver injury.ALT Activity Assay kit has been used to determine the activity of alanine aminotransferase (ALT) in serum samples... 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 | Calcein AM /PI Double Staining Kitis utilized for simultaneous fluorescence staining of viable and dead cells. This kit contains Calcein-AM and Propidium Iodide (PI) solutions, which stains viable and dead cells, respectively(Fig. 1). Calcein-AM, an acetoxymethyl ester of calcein, is highly Calcein AM /PI Double Staining Kitis utilized for simultaneous fluorescence staining of viable and dead cells. This kit contains Calcein-AM and Propidium Iodide (PI) solutions, which stains viable and dead cells, respectively(Fig. 1). Calcein-AM, an acetoxymethyl ester of calcein, is highly lipophilic and cell membrane permeable. Though Calcein-AM itself is not a fluorescent molecule, the calcein generated from Calcein-AM by esterase in a viable cell emits a strong green fluorescence (excitationat 490 nm, emission at515 nm). Therefore, Calcein-AM only stains viable cells. On the other hand, PI, a nuclei staining dye, cannot pass through a viable cell membrane. It reaches the nucleus by passing through disordered areas of dead cell membrane, and intercalates with the DNA double helix of the cell to emit red fluorescence (excitation: 535 nm,emmision: 617 nm). Since both calcein and PI-DNA can be excited with 490 nm, simultaneous monitoring of viable and dead cells is possible with a fluorescence microscope. With 545 nm excitation, only dead cells can be observed (Fig. 1). Since optimal staining conditions differ from cell line to cell line, we recommend that a suitable concentration of PI and Calcein-AM be individually determined. Please note that PI is suspected to be highly carcinogenic;careful handling is required.Required Equipment and Materials:Microscope with 490 nm excitation filter and 530 nm emission filter；CO2incubator；10 µl and 200 µl adjustable pipettes, PBSSolution A (Calcein-AM)；Solution B (PI) Storage Condition: -20oC ；Shipping Condition: blue ice.Application:Assay Procedure1)Add 2.5 µl Solution A and 12.5 µl Solution B to 5 ml PBS to prepare assay solution.*2)Wash the cell with PBS several times to remove residual esterase activity.3)Add 100uLof assay solution to200uL105~106CELLSsolution and incubate the mixture at 37oC for 15 min.4)Detect fluorescence using a fluorescence mircoscope with 490 nm excitationfor simultaneous monitoring of viable and dead cells.With 545 nm excitation, only dead cells can be observed.*The following steps may be necessary tooptimizethe suitable concentration of each reagent:1)Prepare dead cells by 10 min incubation in 0.1% saponin or 0.1-0.5% digitonin or by 30 min incubation in 70% ethanol.2)Stain dead cells with 0.1-10 µM PI solution to find a PI concentration that stains the nucleus only, not the cytosol.3)Stain dead cells with 0.1-10 µM Calcein-AM solution to find a Calcein-AM concentration that does not stain the cytosol. Then stainviable cells with that Calcein-AM solution to check whether the viable cell can be stained... Read More | Product content Q665687Component100 TStorageQ665687AQuick T4 DNA Ligase (15 U/µL)100 µL-20℃. Avoid freeze/thaw cycle.Q665687B2×Quick Ligation Reaction Buffer5×200 µL-20℃. Avoid freeze/thaw cycle. Product IntroductionThe Quick Ligation Reaction Kit allows ligationProduct content Q665687Component100 TStorageQ665687AQuick T4 DNA Ligase (15 U/µL)100 µL-20℃. Avoid freeze/thaw cycle.Q665687B2×Quick Ligation Reaction Buffer5×200 µL-20℃. Avoid freeze/thaw cycle. Product IntroductionThe Quick Ligation Reaction Kit allows ligation of DNA sticky or flush ends in 5 minutes at room temperature (25°C). The kit contains Quick T4 DNA Ligase and 2×Quick Ligation Reaction Buffer optimized for fast and efficient DNA ligation.The ligation efficiency of Quick Ligation is equivalent to 1 hour of conventional ligation with T4 DNA Ligase. The Quick Ligation products can be used directly in routine bacterial transformation experiments.matters needing attention1. This kit enables most of the linkage reactions to reach the reaction endpoint within 5 minutes or less at 25°C. Increasing the reaction time will not enhance the reaction efficiency. If you use the rapid connection reaction after 1 hour, the conversion efficiency will be significantly reduced; if the rapid connection reaction at 25 ℃ overnight, the conversion efficiency will drop to 75%.2. 2×Quick Ligation Reaction Buffer contains ATP, which should be thawed on ice and mixed thoroughly before use. It is recommended to freeze the buffer in small tubes for the first time, so as to avoid repeated freezing and thawing, which will affect the efficiency of DNA ligation.3. Since T4 DNA Ligase contains glycerol, which is sticky and easy to hang on the wall, it is recommended to collect the liquid to the bottom of the tube by centrifugation for a short period of time before use, and the tip of the lance should not go too deep into the liquid surface when taking samples to avoid sticking to the tip of the lance and causing losses.4. If the quick ligation product is used for electrotransformation, the PEG in the quick ligation reaction system will affect the efficiency of electrotransformation, and it is recommended to use a centrifugal column to purify the ligation product from DNA before electrotransformation.Usage1. The reaction solution was prepared according to the following system:*The amount of Insert DNA used: the molar ratio of Vector DNA and Insert DNA is generally 1:3-1:8, and the appropriate molar ratio of Vector DNA and Insert DNA can be selected according to the experimental situation.Calculation of DNA molar number: DNA molar number (nmol)=DNA mass (ng)/( 660daltons x number of inserted DNA bases bp).2. mix gently and centrifuge briefly. react at 25°C for 5 minutes.Note: The reaction time should not exceed 15 minutes, otherwise the connection efficiency will be reduced.3. Do not perform heat inactivation reactions. Centrifuge instantly and collect the solution from the wall to the bottom of the tube.Note: Heat inactivation significantly reduces transformation efficiency due to the presence of PEG in the buffer.4. After the reaction, store the DNA ligation product at 0-4℃, and then carry out transformation experiments; you can also store the DNA ligation product at -20℃.Note: When transforming by chemical method, do not add more than 10% of the volume of the receptor cell for the ligation product.5. Heat shock the ligation product to transform 50 µl of receptor cells or take 1-2 µl of ligation product to electroshock transform 50 µl of receptor cells.Note: 1) When transforming by chemical method, do not add more than 10% of the volume of the receptor cell for the ligation product.(2) If the quick ligation product is used for electrotransformation, it is recommended to use a centrifugal column to purify the ligation product from DNA before electrotransformation because the PEG in the quick ligation reaction system will affect the efficiency of electrotransformation... Read More |