Simplified protocols for the preparation of genomic DNA from bacterial cultures

The development of methodologies for the analysis of microorganisms and microbial ecology, at the molecular level (i.e., nucleic acids, proteins, lipids, and their genes), has progressed phenomenally in recent years. Each methodology has specific advantages and disadvantages, or complications. However, the advances in PCR, cloning, gene probing, sequencing and fingerprinting have enabled techniques exploiting nucleic acids to be utilised extensively for the analysis of microorganisms. Often, such protocols require, firstly, that the nucleic acids are extracted in a form which can be employed for the analyses. This may, in some cases, be more difficult than anticipated initially, since many bacteria are extremely resistant to cell disruption. Typically, these are Gram-positive bacteria (e.g., Mycobacterium spp., Peptococcus spp., Rhodococcus spp., etc.), as well as some Archae (e.g., methanogens), with thick cell walls of polysaccharide or pseudopeptidoglycan, and many species of fungi and algae.