NATURAL TRANSFORMATION OF STREPTOCOCCUS-CRISTA

Over the years Streptococcus gordonii (sanguis) Challis has become the workhorse of genetic manipulations for the sanguis group of oral stre ptococci This is because strain Challis was shown in early studies to be highly naturally competent for transformation. However, Challis is not usually the most appropriate strain to use in studies which focus on oral microbial adherence. We report that other members of the newly reorganized sanguis group, particularly within the species S. crista, display reasonable transformation frequencies, with both plasmid and chromosomal DNA, if transformed at the appropriate time during the gro wth curve. The ability to transform S. crista may be especially import ant for genetic studies of biological properties that appear to be lim ited to these specific streptococcal strains.