Identification of a novel two-component system in Streptococcus gordonii V288 involved in biofilm formation.
Identification of a novel two-component system in Streptococcus gordonii V288 involved in biofilm formation.
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戈登链球菌 V288 中参与生物膜形成的新型双组分系统的鉴定。
DOI：
10.1128/iai.72.6.3489-3494.2004
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
Herzberg,MarkC
中科院分区：
文献类型：
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作者：
Zhang,Yongshu;Lei,Yu;Khammanivong,Ali;Herzberg,MarkC
戈登链球菌是牙齿的先驱定植者，有助于称为牙菌斑的口腔生物膜的形成。为了鉴定可能在生物膜形成中重要的基因，利用S.使用gordoniiV 288。筛选后，在体外生物膜形成聚苯乙烯，一个假定的生物膜缺陷的突变体被分离出来。在这个突变体中，pAK 36被插入到一个基因座编码一个新的双组分系统（bfr[生物膜形成相关]）与两个共转录的基因，形成一个操纵子。bfrA编码一个假定的反应调节，而bfrB编码受体组氨酸激酶。突变株V288和野生株V288在Todd-Hewitt肉汤（THB）中的生长速率相似。构建了abfr-融合菌株。在THB生长过程中，氯霉素乙酰转移酶（chloramphenicol acetyltransferase，BFR）的活性首先在对数生长中期被检测到，在稳定期达到最大值，表明BFR的转录具有生长阶段依赖性。从THB收获后，bfr突变株粘附唾液包被的羟基磷灰石（sHA）的有效性低于野生型菌株V288。为了模拟牙齿的先驱殖民，S。gordoniIV 288与sHA在含有10%唾液的THB中孵育4小时以形成生物膜。分离RNA，并估计bfrAB的表达。在悬浮液中生长的细胞（自由生长的细胞）相比，bfrmRNA表达的无柄细胞sHA的1.8倍，周围的嗜酸性细胞的3.5倍。因此，bfrAB是一个新的双组分系统调节与S。Gordonii体外生物膜形成。
Streptococcus gordoniiis a pioneer colonizer of the teeth, contributing to the initiation of the oral biofilm called dental plaque. To identify genes that may be important in biofilm formation, a plasmid integration library ofS. gordoniiV288 was used. After screening for in vitro biofilm formation on polystyrene, a putative biofilm-defective mutant was isolated. In this mutant, pAK36 was inserted into a locus encoding a novel two-component system (bfr[biofilm formation related]) with two cotranscribed genes that form an operon.bfrAencodes a putative response regulator, whilebfrBencodes a receptor histidine kinase. Thebfrmutant and wild-type strain V288 showed similar growth rates in Todd-Hewitt broth (THB). Abfr-catfusion strain was constructed. During growth in THB, the reporter activity (chloramphenicol acetyltransferase) was first detected in mid-log phase and reached a maximum in stationary phase, suggesting that transcription ofbfrwas growth stage dependent. After being harvested from THB, thebfrmutant adhered less effectively than did wild-type strain V288 to saliva-coated hydroxyapatite (sHA). To simulate pioneer colonization of teeth,S. gordoniiV288 was incubated with sHA for 4 h in THB with 10% saliva to develop biofilms. RNA was isolated, and expression ofbfrABwas estimated. In comparison to that of cells grown in suspension (free-growing cells),bfrmRNA expression by sessile cells on sHA was 1.8-fold greater and that by surrounding planktonic cells was 3.5-fold greater. Therefore,bfrABis a novel two-component system regulated in association withS. gordoniibiofilm formation in vitro.