The Flexibility-Rigidity Coordination of Dense Exopolysaccharide Matrix in Terrestrial Cyanobacteria acclimated to Periodic Desiccation.

The Flexibility-Rigidity Coordination of Dense Exopolysaccharide Matrix in Terrestrial Cyanobacteria acclimated to Periodic Desiccation. Appl Environ Microbiol. 2017 Sep 08;: Authors: Liu W, Cui L, Xu H, Zhu Z, Gao X Abstract A dense exopolysaccharide (EPS) matrix is crucial for cyanobacterial survival in terrestrial xeric environments, in which cyanobacteria undergo frequent expansion and shrinkage processes during environmental desiccation-rehydration cycles. However, it is unclear how terrestrial cyanobacteria coordinate the structural dynamics of the EPS matrix upon the expansion and shrinkage to avoid potential mechanical stress while benefiting from the matrix. In the present study, we sought to answer this question by investigating the gene expression, protein dynamics, enzymatic characteristics and biological roles of WSPA, an abundantly secreted protein, in the representative terrestrial cyanobacterium Nostoc flagelliforme The results demonstrated that WSPA is a novel β-galactosidase that facilitates softening of the EPS matrix by breaking the polysaccharide backbone under substantial moisture or facilitates the thickening and re-linkage of the broken matrix upon drying process, and thus these regulations are well correlated with moisture availability or desiccation-rehydration cycles. This flexibility and rigidity coordination of cyanobacterial extracellular matrix may contribute to a favorable balance of cell growth and s...
Source: Applied and Environmental Microbiology - Category: Microbiology Authors: Tags: Appl Environ Microbiol Source Type: research