This method is able to separate DNA fragments with the size of as small as 10 bp and up to 1 kb with the resolution of as little as 1 bp. While agarose gel electrophoresis is only able to separate DNA fragments with the bigger size that PAGE does or in the size range of 100 nucleotides to around 10 – 15 kb. read more…
Biosurfactants can be quantified by surface and interfacial tension. This is a generic quantitation and thus does not distinguish among different types of surfactants that may be present. Biosurfactants can be compared in terms of the amount they reduce surface or interfacial tension, and the critical micelle concentration (cmc), which is the lowest surfactant concentration above which no further decrease in surface tension or interfacial tension takes place. read more…
After the initial characterization, it is possible to purify further some or all of the plasmid DNAs by RNase digestion and extraction with organic solvents. This further purified DNA is suitable for techniques such as DNA sequencing, subcloning or the production of gene probes. In order to purify plasmid DNA after the isolation process, any residual RNA and contaminating protein are removed. This purification step involves two main steps, which are, first, removing residual RNA by using RNase in order to digest RNA and, second, extract contaminating protein using organic solvents, phenol-chloroform. read more…
You can extract nucleic acids, such as DNA, from bone samples in order to analyze gene expressions, to look for somatic mutations of tumors or other pathological tissue, or for genotyping archive material when other sources of DNA are not available. You can use several kits that have already provided by biotech companies. But, if you are extracting DNA from large number samples, you can use a homemade method as described here to be effective in cost. read more…
RNA can be extracted from blood since whole blood contains nucleated white cells that constitute an easily accessible source. RNA extraction from blood will be more successful if the nucleated white cells are first isolated from the red cells since the red cells are a rich source of ribonucleases that are able to degrade RNA. It is important to minimize degradation by following the appropriate recommendations for handling RNA. The methods of RNA extraction usually comprises of three steps which are cell lysis, partitioning of RNA into a solvent fraction, and recovery of RNA from the solvent by precipitation. read more…