Bacillus anthracis exosporium protein Bc1A affects spore germination, interaction with extracellular matrix proteins, and hydrophobicity
Bacillus anthracis exosporium protein Bc1A affects spore germination, interaction with extracellular matrix proteins, and hydrophobicity
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DOI：
10.1128/iai.00660-07
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发表时间：
2007-11-01
影响因子：
3.1
通讯作者：
O'Brien, Alison D.
中科院分区：
文献类型：
--
作者：
Brahmbhatt, Trupti N.;Janes, Brian K.;O'Brien, Alison D.
炭疽芽孢杆菌类胶原蛋白（Bacilluscollagen-like protein of anthracis，BctA）是炭疽芽孢杆菌孢子外壁上的一种免疫显性糖蛋白。在这里，我们试图评估BclA对孢子萌发的影响，在体外和体内，表面电荷，和与宿主基质蛋白的相互作用。为此，我们在炭疽杆菌Sterne菌株34 F2中构建了无标记的bclA无效突变体。Delta bclA和亲本菌株的生长和产孢率几乎没有区别，但突变孢子的萌发比野生型孢子在体外的萌发更快，并且在60分钟时更完全。此外，皮下或鼻内接种突变孢子的A/J小鼠的平均死亡时间低于野生型孢子，尽管50%的突变孢子两种菌株的致死剂量相似。我们推测，突变体和野生型孢子之间的这些体外和体内差异可能反映了在BclA不存在的情况下萌发体容易接近其受体。我们还比较了Delta bcLA和野生型孢子的疏水性和粘附性。三角洲bcLA孢子显着不防水比野生型孢子，可能是由于结果，细胞外基质蛋白层粘连蛋白和纤连蛋白绑定显着更好的突变体比野生型孢子。这些研究表明，BclA作为一个盾牌，不仅减少了孢子萌发的容易程度，而且还改变了孢子的表面性质，这反过来可能会阻碍孢子与宿主基质物质的相互作用。
Bacillus collagen-like protein of anthracis (BctA) is the immunodominant glycoprotein on the exosporium of Bacillus anthracis spores. Here, we sought to assess the impact of BclA on spore germination in vitro and in vivo, surface charge, and interaction with host matrix proteins. For that purpose, we constructed a markerless bclA null mutant in R anthracis Sterne strain 34F2. The growth and sporulation rates of the Delta bclA and parent strains were nearly indistinguishable, but germination of mutant spores occurred more rapidly than that of wild-type spores in vitro and was more complete by 60 min. Additionally, the mean time to death of A/J mice inoculated subcutaneously or intranasally with mutant spores was lower than that for the wild-type spores even though the 50% lethal doses of the two strains were similar. We speculated that these in vitro and in vivo differences between mutant and wild-type spores might reflect the ease of access of germinants to their receptors in the absence of BclA. We also compared the hydrophobic and adhesive properties of Delta bcLA and wild-type spores. The Delta bcLA spores were markedly less water repellent than wild-type spores, and, probably as a consequence, the extracellular matrix proteins laminin and fibronectin bound significantly better to mutant than to wild-type spores. These studies suggest that BclA acts as a shield to not only reduce the ease with which spores germinate but also change the surface properties of the spore, which, in turn, may impede the interaction of the spore with host matrix substances.