Interspecies Transformation of Streptomycin Resistance in Oral Streptococci

Abstract

Donor deoxyribonucleic acid extracted from streptomycin-resistant (Str R ) mutant derivatives of a variety of strains of Streptococcus mutans, S. salivarius , and S. sanguis was used to transform streptomycin resistance into competent S. sanguis strain Challis. Transfer of genetic markers for sorbitol and mannitol fermentation and for extracellular polysaccharide as demonstrated by colonial morphology was not detected in this study. Reciprocal transformation between strain Challis and other oral streptococci could not be demonstrated. Transformation frequencies for Str R were relatively efficient among S. sanguis strains, with lower but significant frequencies demonstrated with strain Challis and donor deoxyribonucleic acid derived from other oral streptococci.

Transformation of Streptococcus sanguis Challis by plasmid deoxyribonucleic acid from Streptococcus faecalis

“…The maximum transformation frequency (1.8 x 10-5/CFU) was obtained at 90 min. This time sequence agrees completely with previous studies using a chromosomal marker (11).…”

“…Properties of parent bacterial strains. Members of three groups of streptococci, H, N and 0, have been shown to be transformable by chromosomal DNA extracted from homologous and heterologous groups and species of streptococci (11,25,26). The transformable group H strains appear to be the most versatile recipients, in that DNA extracted from groups A, C, D, G, and H have been successfully used in transformation reactions (25).…”

Biology, immunology, and cariogenicity of Streptococcus mutans.

“…However, transfer of other genetic markers such as fermentation of sorbitol and mannitol and the synthesis of watersoluble polysaccharide was not demonstrated. Reciprocal transformation is observed only between SM resistant strain Challis and S. sanguis strains ATCC 10556 and ATCC 10557, but not between strain Challis and S. mutans (101).…”

Detection of streptococcal mutants presumed to be defective in sugar catabolism

“…Streptococcus sanguis Challis is amenable to genetic analysis by transformation (2,21), has been reported to be useful as a recipient for cloned DNA from other species of oral streptococci (11), and can serve as a recipient in streptococcal conjugation experiments (8). Genetically marked variants of this strain would be useful in the eventual construction of a chromosomal map and in the characterization of foreign DNA introduced by cloning or conjugation techniques.…”