Viscosity has dichotomous effects on Bdellovibrio bacteriovorus HD100 predation

Abstract

Summary Bdellovibrio bacteriovorus HD100 is a highly motile predatory bacterium that consumes other Gram‐negative bacteria for its sustenance. Here, we describe the impacts the media viscosity has both on the motility of predator and its attack rates. Experiments performed in polyethylene glycol (PEG) solutions, a linear polymer, found a viscosity of 10 mPa s (5% PEG) negatively impacted predation over a 24‐h period. When the viscosity was increased to 27 mPa s (10% PEG), predation was nearly abolished. Tests with three other B. bacteriovorus strains, i.e., 109J and two natural isolates, found identical results. Short‐term (2‐h) experiments, however, found attack rates were improved in 1% PEG, which had a viscosity of 5.4 mPa s, using bioluminescent prey and their viabilities. In contrast, when experiments were performed in dextran, a branched polymer, no increase in predation was seen even though the viscosity was a comparable 5.1 mPa s. The enhanced attack rates in this solution coincided with a 31% increase in B. bacteriovorus HD100 swimming speeds (62 μm s−1 in 1% PEG vs. 47.5 μm s−1 in HEPES‐salt).

Interactions between Bdellovibrio and like organisms and bacteria in biofilms: beyond predator–prey dynamics

“…BALOs can prey on cells having thick polysaccharide capsules (Koval and Bayer, 1997), they prey under highly viscous conditions (249 cP, 10% polyvinylpyrollidone; 25 cP in 10% polyethylene glycol, 28°C, Sathyamoorthy et al ., 2019; Im et al ., 2019) and are capable of gliding motility (Lambert et al ., 2011). Whether these characteristics, along with their capacity to disrupt EPS components, provide benefits to BALOs preying in biofilms is still not known but seminal studies by the Mitchell group show the predator's gene expression profile within biofilms resembles that of the intraperiplasmic stage or that of predators exposed to a rich broth.…”

Phylogenomic insights into distribution and adaptation of Bdellovibrionota in marine waters

“…1C). Marine and ground water were the most common sources for Bdellovibrionota, which coincides with their preference for environment with low viscosity (21). About 43.40% of Bacteriovoracia and 46.81% of Bdello-group2 genomes were derived from marine waters (Fig.…”

Regularized representation of bacterial hydrodynamics

“…Additionally, these explorations suggest a potential configuration-dependent overestimation or underestimation of bacterial predation by simple force-dipole models that may be of pertinence to more sophisticated computational and theoretical evaluations of predatory bacteria that include relevant physiological factors, such as the possible chemotaxis of predatory species, steric interactions between predator and prey, or the presence of multiple predator or prey bacteria. With multiple recent works having suggested and evaluated predatory bacteria for use in industry [47][48][49], we envisage that the refined hydrodynamic model presented in this work will enable higher fidelity theoretical investigation into the cell-level dynamics of these applications, in addition to forming the basis of models exploring the effects of environment heterogeneity and the impacts of viscosity on predation [32,[50][51][52].…”