Flagella and Their Properties Affect the Transport and Deposition Behaviors of Escherichia coli in Quartz Sand

Abstract

The effects of flagella and their properties on bacterial transport and deposition behaviors were examined by using four types of Escherichia coli (E. coli) with or without flagella, as well as with normal or sticky flagella. Packed column, quartz crystal microbalance with dissipation, visible parallel-plate flow chamber system, and visible flow chamber packed with porous media system were employed to investigate the deposition mechanisms of bacteria with different properties of flagella. We found that the presence of flagella favored E. coli deposition onto quartz sand/silica surfaces. Moreover, by changing the porous media porosity and directly observing the bacterial deposition process, local sites with high roughness, narrow flow channels, and grain-to-grain contacts were found to be the major sites for bacterial deposition. Particularly, flagella could help bacteria swim near and then deposit at these sites. In addition, we found that due to the stronger adhesive forces, sticky flagella could further enhance bacterial deposition onto quartz sand/silica surfaces. Elution experiments indicated that flagella could help bacteria attach onto sand surfaces more irreversibly. Clearly, flagella and their properties would have obvious impacts on the transport/deposition behaviors of bacteria in porous media.

Microfluidics as an Emerging Platform for Exploring Soil Environmental Processes: A Critical Review

“…In microfluidic devices with porous structures, it is possible to mimic and tune the fundamental physicochemical characteristics of pores and aggregates, including distribution, geometry, connectivity, topology, and chemical heterogeneity. Therefore, microfluidics can be a supplementary experimental tool between macroscale column experiments and simulations by providing microscale validation. , …”

Effects of Antibiotic Resistance Genes and Antibiotics on the Transport and Deposition Behaviors of Bacteria in Porous Media

“…In addition, changing solution Ionic strength (IS) could also influence the transport of bacteria by altering the interaction force between bacteria and media. − To testify whether the results achieved in 25 mM NaCl solutions also holds true at other IS conditions, the transport behaviors of both ARB and ASB in quartz sand columns without and with gentamicin (500 μg/L as representative) copresent in cell suspensions were also investigated at both lower (5 mM) and higher (100 mM) ISs at 4 m/d (Figure , right). Due to the lowering energy barrier with increasing IS (Figure S5), the transport for both ARB and ASB without gentamicin decreased with increasing IS from 5 to 100 mM in NaCl solutions (Figure , right, and Table S3).…”

“…Previous studies have found that copresent organic pollutants could adsorb onto bacterial surfaces and thus the surface property of bacteria would be altered, affecting the transport behaviors of bacteria in porous media. 37,44 Batch experiments showed that 54% and 41% of gentamicin (500 μg/L as representative) in suspensions could be adsorbed onto ASB and ARB. The adsorption of gentamicin onto the surfaces of the two strains might also change bacterial surface properties such as cell sizes, ζ potentials, and hydrophobicity.…”

Nematodes and their bacterial prey improve phosphorus acquisition by wheat

“…The experiment was conducted in a glass Petri dish (60 mm in diameter) mimicking the soil environment. We mixed coarse quartz sand (20–30 mesh) and fine quartz sand (40–60 mesh) at a mass ratio of 1 : 1, and the mixed quartz sand was used as model soil media (Zhang et al ., 2021). After adding 16‐g mixed sand to the sterilized Petri dish, soil suspension, which was filtered through a 0.22‐μm membrane to retain only soil nutrients, was added at an amount of 8 ml to each microcosm.…”