Open AccessFunctional analysis of a PcsB‐deficient mutant of group B streptococcus
Author(s) -
Reinscheid Dieter J,
Ehlert Kerstin,
Chhatwal Gursharan S,
Eikmanns Bernhard J
Publication year - 2003
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1016/s0378-1097(03)00167-8
Subject(s) - biology , mutant , microbiology and biotechnology , enolase , bacteria , streptococcus pneumoniae , secretion , wild type , western blot , streptococcus , group b , northern blot , blot , streptococcaceae , gene , gene expression , antibiotics , immunology , genetics , biochemistry , medicine , immunohistochemistry
Group B streptococcus (GBS) is the major cause of bacterial sepsis and meningitis in neonates and poses a significant threat to parturient women. Recently, we identified in GBS the polypeptide PcsB, which is a p rotein required for c ell s eparation of G B S, and which is also involved in the antibiotic sensitivity of these bacteria. In the present study, the introduction of the pcsB ‐carrying plasmid pAT pcsB into the PcsB‐deficient GBS mutant Sep1 restored the phenotype and the antibiotic susceptibility of this strain to that of the GBS wild‐type. Although Northern blots revealed a four‐ to five‐fold increased transcription of pcsB in pAT pcsB ‐carrying GBS strains, overexpression of pcsB did not result in higher amounts of PcsB in the cell wall and in the culture supernatant of GBS, indicating regulatory mechanisms that control the translation or secretion of PcsB in these bacteria. In the culture supernatant of mutant Sep1 significant amounts of enolase were identified. As this protein was also present in extracts of cell wall‐bound proteins from the GBS wild‐type, it can be speculated that GBS can translocate enolase across the cytoplasmic membrane. Northern blot analysis exhibited similar expression of the enolase gene in the GBS strains 6313 and Sep1, indicating that mutant Sep1 is impaired in the anchoring of this protein to its cell wall.