Not merely noxious? Time-dependent hormesis and differential toxic effects systematically induced by rare earth elements in Escherichia coli

Abstract

Progressive rare earth element (REE) enrichment in aquatic environments worldwide and their resulting anthropogenic anomalies have highlighted the need for a better understanding of their biological effects, with a special emphasis on microbial cells since they play a crucial role in good ecosystem functioning. Therefore, the primary aim of this work was to achieve simultaneous characterization of the 16 REE toxicity effects on the growth kinetics of the commonly found Gram-negative bacterium E. coli (BW25113 strain). Bacterial growth curve modelling showed hormetic effects in the presence of REEs, while EC50 determination (in the mid-log phase) indicated that the four HREEs from Er to Lu in addition to Y were the most toxic metals (EC50 in the range of 8.3 to 3 µM), just after Sc (EC50 of 1.1 µM). Additional subcellular parameter assessment revealed cell membrane lipid peroxidation as well as enhanced membrane depolarization and permeability in the presence of La, Gd, or Yb as representatives of LREEs and HREEs. These subcellular effects appeared to be more intense with Gd and Yb compared with La-exposed cells, in relation to the overall higher toxicity potential reported for HREEs on bacterial growth. Also, the cellular ATP production decreased after REE exposure at their EC50. Finally, these results emphasize the importance of growth kinetic consideration as well as the complexity of REE biological effect mechanisms towards bacteria.

Combined omics approaches reveal distinct responses between light and heavy rare earth elements in Saccharomyces cerevisiae

“…1b,d). Yb was 20 times more toxic than La, which is in line with observations using Escherichia coli (Técher et al, 2020). The respective EC10 and EC50 values for La were calculated to be 50 µM and 160 µM and were 6 µM and 8 µM for Yb (Fig.…”

“…The decrease in K was probably triggered to counterbalance the increase in Ca and Na to maintain the cationic balance in the cells. Another hypothesis is that REEs can induce plasma membrane permeabilization as observed in other organisms (Ramos et al, 2016;Técher et al, 2020). Permeabilization of the plasma membrane would allow the nonspecific influx of ions in the cells, explaining the observed increase of cellular cation content following La and Yb exposure.…”

“…More specifically, it was shown that REEs induced oxidative stress through the production of reactive oxygen species, lipid peroxidation, and the modulation of superoxide dismutase, catalase, and glutathione peroxidase in plants, fish, rats and mice and in animal cell lines (including human cells) (Babula et al, 2015;Gonzalez et al, 2014;Liang and Wang, 2013;Pagano et al, 2015;Xu et al, 2016). Other effects have been observed, such as membrane permeability alterations (El-Ramady, 2008;Gao et al, 2017;Técher et al, 2020;Weiwei et al, 2007;Yufeng et al, 2007), mitotic and chromosomal aberrations (Pagano et al, 2015), and the overproduction of exopolysaccharides (Fitriyanto et al, 2011) in microorganisms. However, these aspects of REE toxicity were investigated in diverse organisms, making it difficult to draw comprehensive 3 conclusions.…”

Methane production of rare earth element‐rich Dicranopteris dichotoma and effects of La(III) on anaerobic digestion performance of lignocellulose

“…Some trace elements, such as Fe, Co, Ni, Cu, Zn, Mn, Mo, and W, could improve the methane production at an appropriate concentration by promoting cell synthesis or anaerobic digestion reactions, but they also inhibited anaerobic digestion processes at a high concentrations 13‐15 . REEs shown similar hormesis effects on the performance of anaerobic digestion of animals, plants, and microorganisms 16 . Recently, Fu et al 17 .…”

Spatial distribution of multielements including lanthanides in sediments of Iron Gate I Reservoir in the Danube River

“…Because of the appearance of Ln and the platinum group of elements in higher concentration in the environment compared with their background, these elements are grouped into the fourth group of trace elements that are potentially toxic even at very low concentration and about which not much information is available (Balaram 2016 ; Bott 1995 ). Although, technological application and research interest for Ln have enhanced, environmental transport and fate, and possible accumulation of these elements and their impact on nature and human health, are still limited (Gwenzi et al 2018 ; Vukojević et al 2019 ; Técher et al 2020 ). Regardless if quantification of TCEs is not covered by the EU monitoring programmes, the huge industrial applications of TCEs today and their appearance in different environmental compartments can lead to TCEs becoming future candidates for monitoring.…”