Interactions with Arsenic: Mechanisms of Toxicity and Cellular Resistance in Eukaryotic Microorganisms

Abstract

Arsenic (As) is quite an abundant metalloid, with ancient origin and ubiquitous distribution, which represents a severe environmental risk and a global problem for public health. Microbial exposure to As compounds in the environment has happened since the beginning of time. Selective pressure has induced the evolution of various genetic systems conferring useful capacities in many microorganisms to detoxify and even use arsenic, as an energy source. This review summarizes the microbial impact of the As biogeochemical cycle. Moreover, the poorly known adverse effects of this element on eukaryotic microbes, as well as the As uptake and detoxification mechanisms developed by yeast and protists, are discussed. Finally, an outlook of As microbial remediation makes evident the knowledge gaps and the necessity of new approaches to mitigate this environmental challenge.

Biotechnology Advances in Bioremediation of Arsenic: A Review

“…Microbes such as bacteria, fungi and archaea play an important role in the conversion of inorganic arsenate to an organic state in the geochemical methylation cycle [ 56 ] ( Figure 4 ). Methylation of arsenic by microbes is considered a detoxification pathway in aerobes that converts methylated arsenite (more toxic) to methylated arsenate (less toxic) [ 57 ].…”

Toxicity of arsenic(

“…Overall, the broad range in chronic EC10 values (13-26 000 µg As V L -1 ), EC20 values (18-34 000 µg As V L -1 ) and EC50 values (32-330 000 µg As V L -1 ) covered three to four orders of magnitude and demonstrates that there are species-specific mechanisms of detoxification that have evolved for exposure to As V (De Francisco et al 2021). There was no one taxon that was more sensitive than all others and the range in EC10 values for temperate (13-17 000 µg As V L -1 ) and tropical (14-26 000 µg As V L -1 ) species overlapped, as was the case for the EC20 and EC50 values so that there were no apparent biases in the data set related to taxonomic group or tropical versus temperate species.…”

“…This makes it difficult to attribute differences in chronic toxicity to oxidation state especially when As III may oxidise to As V in test solutions (Neff 1997). There are likely to be species-specific differences in the biological response to arsenic oxidation states due to the evolution of detoxification mechanisms of arsenic (De Francisco et al 2021). Detoxification in many marine organisms involves the biotransformation of As V to As III followed by methylation and metabolism to produce non-toxic organoarsenic forms (for example, AB) that are released into the environment and undergo further transformations (Duncan et al 2015;Kalia and Khambholja 2015;Wang et al 2015).…”

Structural basis for the arsenite binding and translocation of Acr3 antiporter with NhaA folding pattern

“…1,2 Arsenite and antimonite can cause irreparable damage to multiple organs in the human body through arsenic metabolism. [2][3][4][5][6][7] Owing to their widespread distributions in the environment from both geological and anthropogenic sources, 4,7 there is an urgent need to develop effective strategies to avoid the accumulation of these metalloid compounds in crops and to decontaminate polluted areas. Thus, elucidating the transport mechanisms of arsenite and antimonite is of great significance for enhancing the ability of organisms to resist arsenite and antimonite, and to eliminate highly toxic valence arsenic or antimony oxides from the environment.…”

“…Metalloid compounds, particularly arsenite (As) and antimonite (Sb), are naturally toxic metals that can be easily absorbed by organisms when present in excess amounts in soil and water 1,2 . Arsenite and antimonite can cause irreparable damage to multiple organs in the human body through arsenic metabolism 2–7 . Owing to their widespread distributions in the environment from both geological and anthropogenic sources, 4,7 there is an urgent need to develop effective strategies to avoid the accumulation of these metalloid compounds in crops and to decontaminate polluted areas.…”