Institute of Molecular and Cell Biology, University of Tartu, 51010 Tartu, Estonia.
Int J Mol Sci. 2022 May 24;23(11):5898. doi: 10.3390/ijms23115898.
The biofilm of is complexly regulated by several intercellular and extracellular factors. The cell surface adhesin LapA of this bacterium is a central factor for the biofilm and, consequently, the regulation of expression, for example, by Fis. It has been recently shown that peptides in growth media enhance the formation of biofilm, but not as a source of carbon and nitrogen. Moreover, the peptide-dependent biofilm appeared especially clearly in the -overexpression strain, which also has increased LapA. Therefore, we investigate here whether there is a relationship between LapA and peptide-dependent biofilm. The strains with inducible expression and LapA without the vWFa domain, which is described as a domain similar to von Willebrand factor domain A, were constructed. Thereafter, the biofilm of these strains was assessed in growth media containing extracellular peptides in the shape of tryptone and without it. We show that the vWFa domain in LapA is necessary for biofilm enhancement by the extracellular peptides in the growth medium. The importance of vWFa in LapA was particularly evident for the -overexpression strain F15. The absence of the vWFa domain diminished the positive effect of Fis on the F15 biofilm.
的生物膜是由几种细胞内和细胞外因素复杂调节的。该细菌的细胞表面黏附素 LapA 是生物膜的核心因素，因此，例如通过 Fis 对 的表达进行调节。最近已经表明，生长培养基中的肽增强了 的生物膜形成，但不是碳和氮的来源。此外，依赖肽的生物膜在过表达菌株中表现得尤为明显，该菌株还增加了 LapA。因此，我们在这里研究 LapA 是否与依赖肽的生物膜之间存在关系。构建了具有诱导 表达和缺少 vWFa 结构域的 LapA 的 菌株，该结构域被描述为类似于 von Willebrand 因子结构域 A 的结构域。此后，在含有细胞外肽的生长培养基中和不含有细胞外肽的生长培养基中评估了这些菌株的生物膜。我们表明，LapA 中的 vWFa 结构域对于生长培养基中的细胞外肽增强生物膜是必需的。对于过表达菌株 F15，vWFa 在 LapA 中的重要性尤为明显。缺乏 vWFa 结构域会降低 Fis 对 F15 生物膜的积极影响。
