A polysaccharide deacetylase enhances bacterial adhesion in high-ionic-strength environments

Abstract

Differences in ionic strength, pH, temperature, shear forces, and other environmental factors impact adhesion, and organisms have evolved various strategies to optimize their adhesins for their specific environmental conditions. Many species of Alphaproteobacteria, including members of the order Caulobacterales, use a polar adhesin, called holdfast, for surface attachment and subsequent biofilm formation in both freshwater and marine environments. Hirschia baltica, a marine member of Caulobacterales, produces a holdfast adhesin that tolerates a drastically higher ionic strength than the holdfast produced by its freshwater relative, Caulobacter crescentus. In this work, we show that the holdfast polysaccharide deacetylase HfsH plays an important role in adherence in high-ionic-strength environments. We show that increasing expression of HfsH improves holdfast binding in high-ionic-strength environments. We conclude that HfsH plays a role in modulating holdfast binding at high ionic strength and hypothesize that this modulation occurs through varied deacetylation of holdfast polysaccharides.

Bio‐inspired adhesive hydrogel for biomedicine—principles and design strategies

“…Several species of marine bacteria such as Caulobacterale have charged molecules on their holdfast that allow them to attach to surfaces 161 . Increasing the expression of the polysaccharide deacetylase has demonstrated an adhesion enhancement effect 162,163 . Such nonspecific adhesin‐mediated adhesion has also inspired biomimetic design 157,165 .…”

“…Many adhesins have adhesive abilities derived from sticky groups. [161][162][163][164] Several species of marine bacteria such as Caulobacterale have charged molecules on their holdfast that allow them to attach to surfaces. 161 Increasing the expression of the polysaccharide deacetylase has demonstrated an adhesion enhancement effect.…”

“…In order to achieve permanent adhesion to non‐biological surfaces under various complex conditions, various microorganisms have developed a series of universal non‐specific adhesins (Figure 5C–E). Many adhesins have adhesive abilities derived from sticky groups 161–164 . Several species of marine bacteria such as Caulobacterale have charged molecules on their holdfast that allow them to attach to surfaces 161 .…”

“…161 Increasing the expression of the polysaccharide deacetylase has demonstrated an adhesion enhancement effect. 162,163 Such nonspecific adhesin-mediated adhesion has also inspired biomimetic design. 157,165 Inspired by the positively charged polysaccharide intercellular adhesin (PIA) in biofilms, Han et al grafted chitosan to have similar structure and composition with natural PIA as a source of adhesion (Figure 6D).…”

Turning things around: from cationic/anionic complexation-induced nanoemulsion instability to toughened water-resistant waterborne polyurethanes

“…53 The bacteria, which live in freshwater, can anchor themselves to solid surfaces or interlock with other C. crescentus bacteria using a sticky substance on their holdfast. 54 This "magic glue" is created by the mutual attraction of positive and negative charges, which has inspired the design of underwater adhesives.…”