Protein expression and purification Insect cells

ELISA is the most commonly used method of detecting and quantifying the concentration of an antigen in an unknown sample. During the experiment, If you get a weak signal, then make sure reagents are at room temperature before starting the assay. Try increasing incubation times to ensure maximal antibody binding and amplify the signal. Secondly, if you get values above 0 in the negative control indicates a high background signal. Try to consider reducing your antibody concentration and prevent non-specific binding of antibodies by using affinity-purified antibody and suitable blocking buffers. To avoid high well to well variation, do not stack plates during incubation, no bubbles in the plate and wash wells thoroughly to avoid variation.

ELISA is the most commonly used method of detecting and quantifying the concentration of an antigen in an unknown sample. During the experiment, If you get a weak signal, then make sure reagents are at room temperature before starting the assay. Try increasing incubation times to ensure maximal antibody binding and amplify the signal. Secondly, if you get values above 0 in the negative control indicates a high background signal. Try to consider reducing your antibody concentration and prevent non-specific binding of antibodies by using affinity-purified antibody and suitable blocking buffers. To avoid high well to well variation, do not stack plates during incubation, no bubbles in the plate and wash wells thoroughly to avoid variation.

ELISA is the most commonly used method of detecting and quantifying the concentration of an antigen in an unknown sample. During the experiment, If you get a weak signal, then make sure reagents are at room temperature before starting the assay. Try increasing incubation times to ensure maximal antibody binding and amplify the signal. Secondly, if you get values above 0 in the negative control indicates a high background signal. Try to consider reducing your antibody concentration and prevent non-specific binding of antibodies by using affinity-purified antibody and suitable blocking buffers. To avoid high well to well variation, do not stack plates during incubation, no bubbles in the plate and wash wells thoroughly to avoid variation.

Get tips on using T-PER™ Tissue Protein Extraction Reagent to perform Protein isolation Mammalian cells - Rat_Liver

Get tips on using T-PER™ Tissue Protein Extraction Reagent to perform Protein isolation Mammalian cells - Huh7

Get tips on using Pierce™ Coomassie (Bradford) Protein Assay Kit to perform Protein quantification Mammalian cells - RAW264.7

Get tips on using M-PER™ Mammalian Protein Extraction Reagent to perform Protein isolation Mammalian cells - HUVEC

Get tips on using AllPrep Bacterial DNA/RNA/Protein Kit (50) to perform DNA isolation / purification Bacteria - Gram negative Massilia sp

Short hairpin or small hairpin RNA (shRNA) is artificial RNA, which has a hairpin loop structure, and uses inherent microRNA (miRNA) machinery to silence target gene expression. This is called RNA interference (RNAi). These can be delivered via plasmids or viral/bacterial vectors. Challenges in shRNA-mediated gene silencing include: 1. Off-target silencing, 2. Packaging shRNA encoding lentivirus, and 3. Stable transduction in cells. RNAi have been designed to have anywhere from 19-27 bs, but the most effective design has 19 bp. In case commercial shRNAs are not available, potential target sites can be chosen within exon, 5’- or 3’ UTR, depending on which splice variants of the gene are desired. One should use the latest algorithms and choose at least two different sequences, targeting different regions, in order to have confidence in overcoming off-target effects. A BLAST search after selecting potential design will eliminate potential off-target sequences. For the second challenge, sequencing the vector using primers for either strand (50-100 bp upstream) is suggested, along with using enzymatic digestion on agarose gel for the vector. Next, once the shRNA-containing vector is packaged in a virus, it is important to check the viral titer before transduction. Finally, using a marker in the lentiviral vector (fluorescent protein or antibiotic resistance), along with qPCR for target gene expression can help in determining efficacy of transduction and shRNA on its target site.

The RNA interference (RNAi) is used to inhibit gene expression or translation, by neutralizing targeted mRNA molecules. Two types of RNA molecules such as microRNA (miRNA) and small interfering RNA (siRNA) play a central role in RNAi. Few points have to considered to increase the transfection efficiency of siRNA. Always use healthy, actively dividing cells to maximize transfection efficiency. The confluency of cells should be between 50-70%. Always use the most appropriate siRNA concentration to avoid off-target effects and unwanted toxic side effects. Positive and negative controls should be used for each and every experiment to determine transfection efficiency.