title: Comparative analysis of growth-phase-dependent gene expression in virulent and avirulent Streptococcus pneumoniae using a high-density DNA microarray.
abstract: The global pattern of growth-dependent gene expres-sion in Streptococcus pneumoniae strains was evalu-ated using a high-density DNA microarray. Total RNAs obtained from an avirulent S. pneumoniae strain R6 and a virulent strain AMC96-6 were used to compare the expression patterns at seven time points (2.5, 3.5, 4.5, 5.5, 6.0, 6.5, and 8.0 h). The expression profile of strain R6 changed between log and station-ary growth (the Log-Stat switch). There were clear differences between the growth-dependent gene ex-pression profiles of the virulent and avirulent pneumo-coccal strains in 367 of 1,112 genes. Transcripts of genes associated with bacterial competence and capsular polysaccharide formation, as well as clpP and cbpA, were higher in the virulent strain. Our data suggest that late log or early stationary phase may be the most virulent phase of S. pneumoniae.
authors.affiliation: Asian-Pacific Research Foundation for Infectious Diseases (ARFID), Seoul 135-710, Korea.
authors.forename: Kwan Soo
authors.initials: KS
authors.lastname: Ko
authors.forename: Sulhee
authors.initials: S
authors.lastname: Park
authors.forename: Won Sup
authors.initials: WS
authors.lastname: Oh
authors.forename: Ji-Yoeun
authors.initials: JY
authors.lastname: Suh
authors.forename: Taejeong
authors.initials: T
authors.lastname: Oh
authors.forename: Sungwhan
authors.initials: S
authors.lastname: Ahn
authors.forename: Jongsik
authors.initials: J
authors.lastname: Chun
authors.forename: Jae-Hoon
authors.initials: JH
authors.lastname: Song
mesh_terms: D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D013296:Streptococcus pneumoniae / Q000235:genetics* / Q000254:growth & development / Q000472:pathogenicity*; D013997:Time Factors; D014158:Transcription, Genetic / Q000235:genetics; D014774:Virulence / Q000235:genetics