Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
FEMS Microbiol Lett. 2011 Oct;323(2):105-12. doi: 10.1111/j.1574-6968.2011.02366.x. Epub 2011 Aug 16.
The Azospirillum brasilense chemotaxis-like Che1 signal transduction pathway was recently shown to modulate changes in adhesive cell surface properties that, in turn, affect cell-to-cell aggregation and flocculation behaviors rather than flagellar-mediated chemotaxis. Attachment to surfaces and root colonization may be functions related to flocculation. Here, the conditions under which A. brasilense wild-type Sp7 and che1 mutant strains attach to abiotic and biotic surfaces were examined using in vitro attachment and biofilm assays combined with atomic force microscopy and confocal microscopy. The nitrogen source available for growth is found to be a major modulator of surface attachment by A. brasilense and could be promoted in vitro by lectins, suggesting that it depends on interaction with surface-exposed residues within the extracellular matrix of cells. However, Che1-dependent signaling is shown to contribute indirectly to surface attachment, indicating that distinct mechanisms are likely underlying flocculation and attachment to surfaces in A. brasilense.
最近的研究表明，巴西固氮螺菌的趋化样 Che1 信号转导途径调节细胞表面黏附特性的变化，进而影响细胞间聚集和絮凝行为，而不是鞭毛介导的趋化作用。与絮凝行为相关的可能是细胞对表面的附着和对根的定殖等功能。本文通过体外附着和生物膜分析，结合原子力显微镜和共聚焦显微镜，研究了巴西固氮螺菌野生型 Sp7 和 che1 突变株附着于非生物和生物表面的条件。发现可用于生长的氮源是巴西固氮螺菌附着表面的主要调节剂，在体外可以通过凝集素促进，这表明它取决于与细胞细胞外基质表面暴露残基的相互作用。然而，依赖 Che1 的信号转导对表面附着的贡献是间接的，这表明巴西固氮螺菌的絮凝和附着到表面的机制可能不同。
