Genetic Transformation of Streptococcus sanguis (Challis) with Cryptic Plasmids from Streptococcus ferus
AUTOR(ES)
Macrina, Francis L.
RESUMO
By using the basic methodology initially published by Kretschmer et al. (J. Bacteriol. 124:225-231, 1975), we have been able to introduce phenotypically cryptic plasmids from Streptococcus ferus (formerly Streptococcus mutans subsp. ferus) into Streptococcus sanguis by genetic transformation. In this system, the entry of the cryptic plasmids is selected indirectly. This is effected with transforming deoxyribonucleic acid mixtures in which the cryptic plasmid deoxyribonucleic acid is present in an approximate 10-fold molar excess with respect to a plasmid (pVA1) known to confer erythromycin resistance. Under such conditions, 5 to 10% of the pVA1-containing erythromycin-resistant transformants were cotransformed with cryptic plasmid deoxyribonucleic acid. pVA1 may be selectively eliminated by growth of its S. sanguis host strain at 42°C, enabling the construction of isogenic strains with and without S. ferus cryptic plasmids. Comparative physiological studies of such strains have failed to reveal any plasmid-conferred phenotypes in S. sanguis. With this procedure, we have been able to physically separate two small cryptic plasmids (2.4 × 106 and 2.8 × 106 daltons) of S. ferus. Although these plasmids were found naturally to exist in a single S. ferus host, they were able to replicate independently of one another in S. sanguis. Restriction enzyme fingerprinting indicated that these plasmids did not share a common ancestry.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=551006Documentos Relacionados
- Transformation of Streptococcus sanguis Challis with Streptococcus lactis plasmid DNA.
- Transformation of Streptococcus sanguis Challis by plasmid deoxyribonucleic acid from Streptococcus faecalis.
- Chimeric streptococcal plasmids and their use as molecular cloning vehicles in Streptococcus sanguis (Challis).
- Insertional Inactivation of Genes Responsible for the d-Alanylation of Lipoteichoic Acid in Streptococcus gordonii DL1 (Challis) Affects Intrageneric Coaggregations
- Transformation of Streptococcus sanguis with monomeric pVA736 plasmid deoxyribonucleic acid.