title: Transformation of a type 4 encapsulated strain of Streptococcus pneumoniae.
abstract: Streptococcus pneumoniae strain JNR.7/87 is a highly virulent, type 4 encapsulated Gram-positive bacterium whose transformability has not been tested previously, and whose genome is currently being sequenced. The strain was transformed at very low efficiency by addition of exogenous competence-stimulating peptide: However, the efficiency was too low and irreproducible to be useful in many genetic studies. Therefore, the effects on transformation efficiency of changing different components of competence-stimulating peptide-induced transformation have been examined. Screening of growth media was followed by optimization of pre-induction culture acidification, glycine concentration, and induction time. An optimized protocol was developed whereby S. pneumoniae strain JNR.7/87 was transformed reproducibly with a streptomycin resistance (SmR) marker at an efficiency of approximately 10(5) colony forming units per 10(8) cells.
authors: Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111, USA.
authors: A L
authors: AL
authors: Bricker
authors: A
authors: A
authors: Camilli
mesh_terms: D001426:Bacterial Proteins / Q000494:pharmacology; D003470:Culture Media / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000494:pharmacology; D005998:Glycine; D006801:Humans; D013296:Streptococcus pneumoniae / Q000235:genetics* / Q000254:growth & development; D013997:Time Factors; D014169:Transformation, Bacterial / Q000187:drug effects
chemical_list: D001426:Bacterial Proteins; C061262:ComA protein, Bacteria; D003470:Culture Media; D004268:DNA-Binding Proteins; D005998:Glycine