Genetic transformation of Bacillussubtilis by extracellular DNA

Abstract

This chapter discusses the circulating nucleic acids in higher organisms. DNA is able to leave bacteria and enter other bacteria and the mechanisms and situations involved are readily understood. Bacterial DNA can move from members of one strain to those of another by means of conjugation or transduction, which does not strictly involve extracellular release of DNA. Bacteria possess several extra chromosomal factors including the F factor (the first fertility factor), R factors (antibiotic resistance transfer factors), and bacteriocinogenic factors, which are distinguishable by their molecular weight. F and R factors and some bacteriocinogens have a molecular weight of 6–140 × l06, corresponding to 100 to 200 genes, while many bacteriocinogens have a molecular weight of 4–5 × 106—about 15 genes. Transformation also has been achieved by providing one strain of bacteria with non-purified DNA found in the culture medium of another strain.