siRNA / miRNA gene silencing Human COV-434

Cell cytotoxicity assays measure the ability of certain compounds or chemical mediators to reduce the viability of the cells. The term cell cytotoxicity assay can sometimes be used interchangeably with cell proliferation assay. Healthy living cells can be identified by the use of formazan dyes, protease biomarkers or by measuring ATP content. The formazan dyes are chromogenic products formed by the reduction of tetrazolium salts by dehydrogenases, such as lactate dehydrogenase (LDH) and reductases that are released during cell death. Common tetrazolium salts include INT, MTT, MTS and XTT. Cell cytotoxicity can also be measured by using the SRB and WST-1 assays. These assays can usually be used in a high-throughput fashion and can be quantitated by measuring absorbance, colorimetry or luminescence. All these assays require similar numbers of cell plating at the initiation, a time course of treatment with the cytotoxic agent and at least triplicates for each condition at every point of analysis. Cell shrinkage, plasma membrane blebbing, cell detachment, externalization of phosphatidylserine, nuclear condensation and ultimately DNA fragmentation are well-described features of apoptosis. The assays that rely on cell membrane integrity for their function, may not be able to quantify early apoptosis. Therefore, in order to distinguish early apoptotic vs. late apoptotic or necrotic cells, additional flow cytometry techniques can be used. A combination of Annexin V and PI (propidium iodide) can be used to distinguish early (Annexin V+/PI-) and late apoptotic (Annexin V+/PI+) cells. Sometimes, caspase assays are used in order to differentiate the stages of apoptosis.

A PCR reaction consists of the template DNA, two primers covering the amplification site, an enzyme, and buffers. However, non-specific product amplification and primer-dimer formation during set-up are major causes of PCR failure. Nevertheless, high-quality DNA polymerase and optimize reaction buffers will certainly lead to a successful PCR reaction

A PCR reaction consists of the template DNA, two primers covering the amplification site, an enzyme, and buffers. However, non-specific product amplification and primer-dimer formation during set-up are major causes of PCR failure. Nevertheless, high-quality DNA polymerase and optimize reaction buffers will certainly lead to a successful PCR reaction.

A PCR reaction consists of the template DNA, two primers covering the amplification site, an enzyme, and buffers. However, non-specific product amplification and primer-dimer formation during set-up are major causes of PCR failure. Nevertheless, high-quality DNA polymerase and optimize reaction buffers will certainly lead to a successful PCR reaction.

A PCR reaction consists of the template DNA, two primers covering the amplification site, an enzyme, and buffers. However, non-specific product amplification and primer-dimer formation during set-up are major causes of PCR failure. Nevertheless, high-quality hot-start DNA polymerase and optimize reaction buffers will certainly lead to a successful PCR reaction

Get tips on using TRIzol Reagent to perform RNA isolation / purification Cells - immortalized SHG-44

Get tips on using RNeasy Mini Kit to perform RNA isolation / purification Cells - immortalized SHG-44

Get tips on using Cell Lysis Buffer (10X) to perform Protein isolation Mammalian cells - KC02-44D

Get tips on using CelLytic™ NuCLEAR™ Extraction Kit to perform Protein isolation Mammalian cells - KC02-44D

The most widely used method for protein quantification is by spectrophotometry. The concentration of the protein in the samples is measured at an absorbance of 280 nm. The absorbance of the sample protein is then plotted against a standard curve. This method allows for total protein quantification in a sample (cell and tissue extracts). Before analysing the concentration of protein in the sample, it is important to choose the right test method.  For high protein concentration samples (above 5 - 160 mg/ml) the best method is to use the Biuret test. For low concentrations samples (between 1 - 2000µg/ml) the best methods are Lowry assay, BCA assay, Bradford assay and coomassie blue (for exact sensitivity of the test kits you use, refer to manufacturer's protocol). If the samples contain detergents like Triton X-100 then BCA assay is the best choice. For samples that have proteins larger than 3 KDa in size Bradford assay is the best choice. Each method has advantages and disadvantages, plan your analysis considering your sample characteristics.