These systems are an effective although not infallible means of protecting bacteria from infection. The enzyme utilizes ATP to create new phosphodiester bonds, covalently linking together the ends of DNA strands. Recently, thermostable polymerases have become important, e.g. Taq DNA polymerase from Thermus aquaticus . This bacterium has evolved to grow in hot springs at temperatures which kill most other species. The practical application of molecular biology is founded on our understanding of microorganisms.
Microbiology is thus a central discipline in modern biology.
Biology of Micro-organisms.