Diplococcus pneumoniae transformation

However, the first mutants which were recognized as affecting mismatch repair were found in bacteria. The hex mutant of Streptococcus (Diplococcus) pneumoniae, which increases the transformation rate of certain markers a hundred-fold, was found to be a mutator. Transformation in S. pneumoniae involves the uptake of a single strand of donor DNA and efficiency is limited by the correction of the mutational difference between donor and recipient. In /iex-mutants, the directionality of this correction is abolished (Lacks, 1970). Subsequently a number of... 

Lacks, S.A. (1970). Mutants of Diplococcus pneumoniae that lack deoxyribonucleases and other activities possibly pertinent to genetic transformation. J. Bacteriol. 101, 119-131. 

Avery and his co-workers studied the life cycle and chemical make-up of Diplococcus pneumoniae, or pneumococci, a species of bacteria that causes pneumonia. Avery s interest was sparked by British microbiologist Frederick Griffith s work with pneumococci. In 1928, Griffith described an experiment in which he injected mice with a mixtnre of a harmless strain of living pneumococci and the dead remains of a vimlent strain of the bacteria. The mice died from infection by the live organisms of the vimlent strain, though the organisms had been dead when they were administered. By 1932 Avery focnsed on transformation—a process by which heritable characteristics of one species are incorporated into another different species. 

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