Glucose-related dissociation between icaADBC transcription and biofilm expression by Staphylococcus epidermidis: Evidence for an additional factor required for polysaccharide intercellular adhesin synthesis
Glucose-related dissociation between icaADBC transcription and biofilm expression by Staphylococcus epidermidis: Evidence for an additional factor required for polysaccharide intercellular adhesin synthesis
复制标题
DOI：
10.1128/jb.185.9.2879-2886.2003
复制
发表时间：
2003-05-01
影响因子：
3.2
通讯作者：
Mack, D
中科院分区：
文献类型：
--
作者：
Dobinsky, S;Kiel, K;Mack, D
在大多数菌株中，表皮葡萄球菌中的生物膜形成取决于icaADBC基因座的活性。编码胞间多糖粘附素（PIA）合成酶的操纵子的表达取决于多种外源环境条件，并且至少部分地受替代σ因子σ（B）调节。我们研究了伊卡操纵子的转录调控和在不同葡萄糖含量的生长条件下表达的相应表型。在葡萄糖存在下，S. epidermidis表现出PIA和生物膜阳性表型，而伊卡转录在生长的后指数期和稳定期下调。令人惊讶的是，尽管表达PIA和生物膜阴性表型，但在不存在葡萄糖的情况下，在生长稳定期仍可检测到伊卡的最大转录。在体外酶的测定和表型特征表明，丰富的伊卡mRNA的量是功能活跃的，因为诱导静止期细胞与葡萄糖导致立即PIA合成。生物膜形成的诱导可以被氯霉素完全抑制，氯霉素在生物膜积累的后期阶段给予，也抑制了预先形成的生物膜的进一步发展，这表明生物膜阳性表型的表达需要另外的icaADBC非依赖性因子的连续翻译。
Biofilm formation in Staphylococcus epidermidis depends, in the majority of the strains, on the activity of the icaADBC locus. The expression of the operon that encodes the synthetic enzymes of the intercellular polysaccharide adhesin (PIA) depends on a variety of exogenic environmental conditions and is, at least in part, regulated by the alternative sigma factor sigma(B). We investigated the transcriptional regulation of the ica operon and the respective phenotypes expressed under growth conditions differing in the content of glucose in the growth medium. In the presence of glucose, S. epidermidis exhibited a PIA- and biofilm-positive phenotype whereas ica transcription was down-regulated in the postexponential and stationary phases of growth. Surprisingly, maximum transcription of ica was detectable in the stationary phase of growth in the absence of glucose despite the expression of a PIA- and biofilm-negative phenotype. In vitro enzymatic assays and phenotypic characterization showed that the abundant amount of ica mRNA was functionally active because induction of stationary-phase cells with glucose led to immediate PIA synthesis. Induction of biofilm formation could be completely inhibited by chloramphenicol, which, given at a later stage of biofilm accumulation, also inhibited further development of preformed biofilm, indicating that continuous translation of an additional, icaADBC-independent factor is required for the expression of a biofilm-positive phenotype.