Perfluoroalkyl Substances Increase the Membrane Permeability and Quorum Sensing Response in Aliivibrio fischeri

Abstract

Perfluoroalkyl substances (PFAS) are used in a variety of products and are ubiquitous in the environment. They have been found to associate with eukaryotic cell membranes and alter membrane properties. Bacteria are exposed to elevated concentrations of PFAS in some environments; nevertheless, the effect of PFAS exposure on microbial membranes has not yet been studied. Some quorum sensing pathways require the passive diffusion of signaling molecules through cell membranes. Quorum sensing initiates a variety of bacterial processes, such as biofilm formation and antibiotic production. If PFAS exposure increased the microbial quorum sensing response, these processes could be initiated at lower population densities, with wide-ranging ramifications for PFAS-impacted environments. This study examined the effect of perfluorinated alkyl sulfonates and carboxylates on quorum sensing in a model bacterium, Aliivibrio fischeri. Results showed that cultures exposed to PFAS were brighter after they received the signaling molecule. The observed increase in luminescence was dose-dependent and increased with the fluorinated carbon number. Specifically, perfluorooctanesulfonate increased luminescence at levels as low as 10 μg/L. PFASexposed bacteria were also more permeable to a semi-membrane permeable dye. Therefore, it is likely that increased permeability was, at least in part, the cause of increased luminescence.

Partitioning and Accumulation of Perfluoroalkyl Substances in Model Lipid Bilayers and Bacteria

“…PFAS have also been associated with an inhibition in gap junction communication in rat and dolphin cell lines . The effects of PFAS on bacteria have received less attention; although at concentrations of 22–110 mg/L, they increased floc formation of Rhodococcus jostii and inhibited microbial degradation of trichloroethylene by Dehalococcoides mccartyi enrichments. , At lower concentrations (100 μg/L), PFAS increased bacterial mobility in a model aquifer system, and at concentrations as low as 10 μg/L, PFOS increased the sensitivity of the quorum sensing response in Aliivibrio fischeri . PFAS clearly affect a variety of biota, yet their mechanisms of action, and whether they are similar in bacteria and eukaryotes, remain unclear.…”

Direct effects of organic pollutants on the growth and gene expression of the Baltic Sea model bacteriumRheinheimerasp.BAL341

“…Still, there is research showing that these pollutants cause for example luminescence inhibition in the marine bacterium Vibrio fischeri and the cyanobacterium Anabaena sp. strain CPB4337 (Rosal et al ., ), cause membrane disruption, oxidative stress and DNA damage in Escherichia coli bacteria (Liu et al ., ), and that they influence bacterial membrane fluidity, permeability and quorum sensing (Fitzgerald et al ., , ). Furthermore, there is a 16S rRNA gene survey indicating that these compounds can drive selective changes in bacterial sediment communities (Sun et al ., ).…”

Nothing lasts forever: understanding microbial biodegradation of polyfluorinated compounds and perfluorinated alkyl substances

“…Although solubilities can be measured directly, much less is known about how PFAS compounds such as PFOA and PFOS might move out of an aqueous environment and into bacterial cells. There is evidence that these compounds can partition into cellular membranes passively (Fitzgerald et al ., 2018b ); in one case, this was shown to affect the quorum sensing response (Fitzgerald et al ., 2018a ). It is less clear if these molecules are actively transported, perhaps adventitiously by transporters evolved for other uptake functions.…”