Tolerance, Adaptation, and Cell Response Elicited by Micromonospora sp. Facing Tellurite Toxicity: A Biological and Physical-Chemical Characterization

Abstract

The intense use of tellurium (Te) in industrial applications, along with the improper disposal of Te-derivatives, is causing their accumulation in the environment, where oxyanion tellurite (TeO32−) is the most soluble, bioavailable, and toxic Te-species. On the other hand, tellurium is a rare metalloid element whose natural supply will end shortly with possible economic and technological effects. Thus, Te-containing waste represents the source from which Te should be recycled and recovered. Among the explored strategies, the microbial TeO32− biotransformation into less toxic Te-species is the most appropriate concerning the circular economy. Actinomycetes are ideal candidates in environmental biotechnology. However, their exploration in TeO32− biotransformation is scarce due to limited knowledge regarding oxyanion microbial processing. Here, this gap was filled by investigating the cell tolerance, adaptation, and response to TeO32− of a Micromonospora strain isolated from a metal(loid)-rich environment. To this aim, an integrated biological, physical-chemical, and statistical approach combining physiological and biochemical assays with confocal or scanning electron (SEM) microscopy and Fourier-transform infrared spectroscopy in attenuated total reflectance mode (ATR-FTIR) was designed. Micromonospora cells exposed to TeO32− under different physiological states revealed a series of striking cell responses, such as cell morphology changes, extracellular polymeric substance production, cell membrane damages and modifications, oxidative stress burst, protein aggregation and phosphorylation, and superoxide dismutase induction. These results highlight this Micromonospora strain as an asset for biotechnological purposes.

Impact of Biogenic and Chemogenic Selenium Nanoparticles on Model Eukaryotic Lipid Membranes

“…2925 cm −1 ) and either asymmetric −CH disorder of lipids. 34 Integral ratios for the OM were slightly lower than the bSeNP extract and cSeNPs_OM, whereas the latter showed the lowest degree of acyl-chain order (Figure 2C). These results suggest that the OM featured a lower amount of saturated lipids, these biomolecules were more disordered in cSeNPs_OM than in the other samples, 34 and saturated lipids may preferentially interact with bSeNPs.…”

“…2955 cm –1 ; A νas(CH 2 ) / A νas(CH 3 ) ) or symmetric −CH 2 (ca. 2850 cm –1 ; A νas(CH 2 ) / A νs(CH 2 ) ) stretching vibrations indicate the fluidity and acyl chain disorder of lipids . Integral ratios for the OM were slightly lower than the bSeNP extract and cSeNPs_OM, whereas the latter showed the lowest degree of acyl-chain order (Figure C).…”

“…Integral ratios for the OM were slightly lower than the bSeNP extract and cSeNPs_OM, whereas the latter showed the lowest degree of acyl-chain order (Figure C). These results suggest that the OM featured a lower amount of saturated lipids, these biomolecules were more disordered in cSeNPs_OM than in the other samples, and saturated lipids may preferentially interact with bSeNPs. In turn, lipids within the OM appear to have more freedom than in the bSeNP extract, making them able to organize and interact with other biomolecules.…”

Microbial mechanisms to transform the super-trace element tellurium: a systematic review and discussion of nanoparticulate phases

“…Similarly, acetate transport proteins could take up tellurite in some bacteria, and the resistance of these bacteria to tellurite could increase when the competitor acetate was present (Borghese et al 2010 ). In a Micromonospora strain isolated from a metal-rich environment, increasing the saturation and branched chain fatty acids may stiffen the cell membrane, resist excessive tellurium oxyanions entering the cell membrane, and avoid oxidative bursts associated with tellurite in order to cope with high concentrations (5 mM) of tellurite (Piacenza et al 2022 ). Additionally, surface adsorption of tellurite could also control tellurite uptake (Goff et al 2021b ).…”