Regulation of competence for genetic transformation in Streptococcus pneumoniae

摘要

Genetic transformation, defined as the ability of bacteria to take up high molecular weight exogenous DNA, was first discovered in Streptococcus pneumoniae (Griffith 1928). In several bacterial species, it depends on achieving a specialized cellular state termed competence, and in Strep, pneumoniae this state is transitory. The pneumococcal transformation system differs from the best-studied system, that of Bacillus subtilis, in two important aspects. First, while cultures of B. subtilis are heterogeneous, with only a fraction (ca 15%) of cells achieving competence, all pneumococcal cells in a culture become competent. Seconds competence develops post-exponentially in B. subtilis, whereas in Strep, pneumoniae it occurs during the exponential phase of growth.