Bacteria in arsenic-rich environments exhibit multiple operons and the arsR gene, indicating more comprehensive arsenic detoxification mechanisms compared to E. coli, supporting higher efficiency in arsenic processing and removal.
The claim that bacteria in arsenic-rich environments are more efficient at processing arsenic into arsenite and removing it from their cells is supported by the evidence in Figure 1:
(A) H. arsenicoxydans and O. tritici possess multiple operons controlling the production of proteins involved in processing and removing arsenite from cells. In contrast, E. coli has only one operon dedicated to arsenic removal. The presence of multiple operons in arsenic-rich bacteria suggests a more comprehensive and potentially more efficient arsenic detoxification mechanism.
(B) Both H. arsenicoxydans and 0. tritici contain the ars R gene, responsible for encoding a repressor that activates the operon responsible for eliminating arsenite from the cell. This gene presence implies a regulatory system that effectively manages arsenic detoxification mechanisms, likely enhancing their efficiency in dealing with high arsenic levels.
Complete Question:
Arsenic is a toxic element found in both aquatic and terrestrial environments. Scientists have found genes that allow bacteria to remove arsenic from their cytoplasm. Arsenic enters cells as arsenate that must be converted to arsenite to leave cells. Figure 1 provides a summary of the arsenic resistance genes found in the operons of three different bacteria. E. coli R773 is found in environments with low arsenic levels. Herminiimonas arsenicoxydans and Ochrobactrum tritici are both found in arsenic‑rich environments.