Responses of Periphyton to Fe₂O₃ Nanoparticles: A Physiological and Ecological Basis for Defending Nanotoxicity

Abstract

The toxic effects of nanoparticles on individual organisms have been widely investigated, while few studies have investigated the effects of nanoparticles on ubiquitous multicommunity microbial aggregates. Here, periphyton as a model of microbial aggregates, was employed to investigate the responses of microbial aggregates exposed continuously to FeO nanoparticles (5.0 mg L) for 30 days. The exposure to FeO nanoparticles results in the chlorophyll (a, b, and c) contents of periphyton increasing and the total antioxidant capacity decreasing. The composition of the periphyton markedly changes in the presence of FeO nanoparticles and the species diversity significantly increases. The changes in the periphyton composition and diversity were due to allelochemicals, such as 3-methylpentane, released by members of the periphyton which inhibit their competitors. The functions of the periphyton represented by metabolic capability and contaminant (organic matter, nitrogen, phosphorus and copper) removal were able to acclimate to the FeO nanoparticles exposure via self-regulation of morphology, species composition and diversity. These findings highlight the importance of both physiological and ecological factors in evaluating the long-term responses of microbial aggregates exposed to nanoparticles.

Effects of Nanoplastics on Freshwater Biofilm Microbial Metabolic Functions as Determined by BIOLOG ECO Microplates

“…At the end of exposure, the biofilms were carefully peeled off from the cobblestones using a sterile brush and transferred to flasks where they were blended using sonication (40 K Hz, 100 W, 1 min) and centrifugated in a centrifugal tube before use in further experimentation [31,32].…”

How Microbial Biofilms Control the Environmental Fate of Engineered Nanoparticles?

“…Regarding specific impacts on EPS matrix, several studies report the extracellular production of molecules by microbes exposed to ENPs (Maurer-Jones et al, 2013;Zhu et al, 2018aZhu et al, ,b, 2019. Particularly, the formation of more compacted biofilms and higher active site densities was observed, following a significant increase in EPS production after exposure to ENPs (Hou et al, 2015;Tang et al, 2017;Liu et al, 2018;Miao et al, 2018;Zhu et al, 2018aZhu et al, ,b, 2019. Interestingly, this increased EPS production is thought to reduce cells damage (Hessler et al, 2012), particularly when most metal-bearing ENPs are known to produce ROS at their surface (Nel et al, 2006) which promotes oxidative stress at the cellular level.…”

“…Multi-species communities exposed to ENPs may experience important changes in microbial consortium structure with significant evolutions in microbial diversity (Binh et al, 2014(Binh et al, , 2016Echavarri-Bravo et al, 2015;Jomini et al, 2015;Tang et al, 2017;Miao et al, 2018;Zhu et al, 2018aZhu et al, ,b, 2019. These remodeling of microbial consortia can potentially modify the types of metabolisms expressed in these communities and impact the environmental ENPs fate.…”

Integration of subcellular partitioning and chemical forms to understand silver nanoparticles toxicity to lettuce (Lactuca sativa L.) under different exposure pathways

“…Specimens were washed three times at 10 min intervals with MPB, incubated for 1 h in 1% osmium tetroxide, and dehydrated in a gradient ethanol series (30%, 50%, 70%, and 100%) for 30 min for each step (Gonçalves et al, 2018). They were then soaked in a 1: 1 mix of acetone: resin for 12 h and 100% resin to polymerize overnight at 37 C, and then another 12 h at 60 C. After double staining with 3% uranyl acetate and lead nitrate, the specimens were sliced (50e100 nm thickness) and examined by transmission electron microscope (TEM, Hitachi, HT-7700, Japan) at an accelerating voltage of 80 kV (Tang et al, 2017).…”