Total Genomic DNA and Protein Extraction from Escherichia coli K12 Cells on the Bead Ruptor 4

Escherichia coli (E. coli) is frequently used as a model organism in microbiology and molecular biology studies. E.coli was one of the first organisms to have its genome completely sequenced which has allowed it to be a major contributor to recombinant DNA technology. The process of gene cloning in E.coli involves a series of steps including the isolation of target DNA or protein. Analyte extraction is typically done through sonication or bead milling. Sonication is the most popular technique for extracting proteins. With the sonication process, the cells are lysed via cavitation produced by a high frequency oscillating probe to disrupt cellular membranes releasing the internal cellular components. There are a number of drawbacks to the use of sonicators including excessive heat generation, variations in yield and sonicators are only able to process one sample per cycle. Ultrasonic homogenizers also shear DNA making them unsuitable for many DNA applications.

As an alternative to ultrasonic homogenizers, bead mills are higher throughput homogenizers that are able to process multiple samples at once through the rapid oscillation of tubes containing high speed projectiles that impact and dissociate cells. The efficiency of the bead milling process allows it to quickly extract cellular compounds from cultured cells such as E. coli while maintaining their molecular integrity. The Omni Bead Ruptor™ 4 is designed as a small footprint bead mill to facilitate efficient lysis of tissues and cells.

The Omni Bead Ruptor 4 is capable of homogenizing up to four 0.5 mL, 1.5 mL, 2mL or one 7 mL sample using bead media to assist in sample disruption process.

Here, we demonstrate the extraction of DNA and protein from E. coli K12 cells using the Omni Bead Ruptor 4. Extraction efficiency and analyte integrity was evaluated.

Table 1: DNA and protein concentrations measured post homogenization.