Protein expression and purification Mammalian cells

Generally it has been difficult to isolate high-quality RNA from yeast because of problems disrupting the cells. Use of enzymes to disrupt cell wall can alter gene expression profiles. Therefore, physical disruption can result in high quality RNA for all downstream processing. Use of DNAse and proteinase K will remove traces of DNA contamination and proteins respectively.

Generally it has been difficult to isolate high-quality RNA from yeast because of problems disrupting the cells. Use of enzymes to disrupt cell wall can alter gene expression profiles. Therefore, physical disruption can result in high quality RNA for all downstream processing. Use of DNAse and proteinase K will remove traces of DNA contamination and proteins respectively.

Generally it has been difficult to isolate high-quality RNA from yeast because of problems disrupting the cells. Use of enzymes to disrupt cell wall can alter gene expression profiles. Therefore, physical disruption can result in high quality RNA for all downstream processing. Use of DNAse and proteinase K will remove traces of DNA contamination and proteins respectively.

Get tips on using pPICZα A, B, & C Pichia Vectors to perform Protein expression and purification Yeast - Pichia pastoris EDIII-D1

Get tips on using Micro BCA™ Protein Assay Kit to perform Protein quantification Mammalian cells - Human pluripotent stem cells

Get tips on using Pierce™ BCA Protein Assay Kit to perform Protein quantification Mammalian cells - Human pluripotent stem cells

Get tips on using Qubit™ Protein Assay Kit to perform Protein quantification Mammalian cells - HeLa

An alternative to culture-based cell death detection is an assessment of other cell viability indicators using fluorescent dyes, including membrane potential and membrane integrity. Live/Dead assays differentiates live and dead cells using membrane integrity as a proxy for cell viability and are based on a fluorescent staining procedure followed by detection using flow cytometry. However, samples preparation for such flow cytometry-based techniques could be challenging. Cell harvesting by trypsinization, mechanical or enzymatic cell disaggregation from tissues, extensive centrifugation steps, may all lead to preferential loss of apoptotic cells. To overcome this strictly follow manufacturers instruction of the detection kit.

The process of RNA extraction from bacteria, in general, involves an RNA-protective, effective lysis of bacterial cell wall (which may pose difficulties). EDTA promotes loss of outer membrane to provide lysozyme with access to peptidoglycan. Another common method for cell wall lysis is mechanical disruption using a homogenizer (applied for gram-positive bacteria and some strains of gram-negative bacteria). Following lysis, it is necessary to disrupt protein-nucleic acid interactions, which can be achieved by adding sodium dodecyl sulfate (SDS). Next step involves using phenol-chloroform-isoamyl alcohol extraction, where RNA can be obtained from the bottom organic phase, the top phase consists of DNA and the interphase contains proteins. Isoamyl alcohol is an inert and optional addition to this mixture and is added as an anti-foaming reagent to reduce the interphase. Following RNA extraction, the samples should be checked for its quality by gel electrophoresis (23S and 16S rRNAs and 5s rRNA and tRNA bands) or UV spectrophotometric or fluorescence methods.

The process of RNA extraction from bacteria, in general, involves an RNA-protective, effective lysis of bacterial cell wall (which may pose difficulties). EDTA promotes loss of outer membrane to provide lysozyme with access to peptidoglycan. Another common method for cell wall lysis is mechanical disruption using a homogenizer (applied for gram-positive bacteria and some strains of gram-negative bacteria). Following lysis, it is necessary to disrupt protein-nucleic acid interactions, which can be achieved by adding sodium dodecyl sulfate (SDS). Next step involves using phenol-chloroform-isoamyl alcohol extraction, where RNA can be obtained from the bottom organic phase, the top phase consists of DNA and the interphase contains proteins. Isoamyl alcohol is an inert and optional addition to this mixture and is added as an anti-foaming reagent to reduce the interphase. Following RNA extraction, the samples should be checked for its quality by gel electrophoresis (23S and 16S rRNAs and 5s rRNA and tRNA bands) or UV spectrophotometric or fluorescence methods.