Genetic Exchange in Gram-Positive Bacteria

This chapter presents an over of gene transfer systems and their applications in several important groups of gram-positive bacteria. Bacteriophage-mediated generalized transduction is an important method of genetic manipulation that can be accomplished using either lytic or temperate phages. The competent state is transiently induced when a culture of Streptococcus pneumoniae achieves a critical cell density. Whether or not this element retains the ability to transfer itself to other Staphylococci or has become inactivated by mutation remains to be determined. A section focuses on the lactococci and related food-fermenting bacteria. In the e of organisms like Lactococcus lactis, the relative ease of transformation- and conjugation-based transfer methods might account for this trend. The use of the upp gene and the pheS* sette in the development of a counter selection system for Enterococcus faecalis described elsewhere in the chapter may be adaptable to various LAB strains, although this will need to be tested for each species. The primary focus of the chapter is on advances that have been developed for genetic analysis of Bacillus subtilis and also on some basic protocols for particularly important types of genetic manipulation. In contrast to the gram+ bacteria, members of the genus Mycobacterium belong to the cluster of so-called high-GC gram+ bacteria based on the nucleotide composition of their genomes.