title: Bacterial resistance to arsenic protects against protist killing.
abstract: Protists kill their bacterial prey using toxic metals such as copper. Here we hypothesize that the metalloid arsenic has a similar role. To test this hypothesis, we examined intracellular survival of Escherichia coli (E. coli) in the amoeba Dictyostelium discoideum (D. discoideum). Deletion of the E. coli ars operon led to significantly lower intracellular survival compared to wild type E. coli. This suggests that protists use arsenic to poison bacterial cells in the phagosome, similar to their use of copper. In response to copper and arsenic poisoning by protists, there is selection for acquisition of arsenic and copper resistance genes in the bacterial prey to avoid killing. In agreement with this hypothesis, both copper and arsenic resistance determinants are widespread in many bacterial taxa and environments, and they are often found together on plasmids. A role for heavy metals and arsenic in the ancient predator-prey relationship between protists and bacteria could explain the widespread presence of metal resistance determinants in pristine environments.
authors.affiliation: Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China.
authors.forename: Xiuli
authors.initials: X
authors.lastname: Hao
authors.affiliation: Department of Biology, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Xuanji
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Infectious Diseases, Institute for Biomedicine, Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden.|Center for Antibiotic Resistance Research (CARe) at the University of Gothenburg, Göteborg, Sweden.
authors.forename: Chandan
authors.initials: C
authors.lastname: Pal
authors.affiliation: School of Biosciences, The University of Nottingham, Sutton Bonington Campus, Sutton Bonington, Leicestershire, LE12 5RD, UK.
authors.forename: Jon
authors.initials: J
authors.lastname: Hobman
authors.affiliation: Department of Infectious Diseases, Institute for Biomedicine, Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden.|Center for Antibiotic Resistance Research (CARe) at the University of Gothenburg, Göteborg, Sweden.
authors.forename: D G Joakim
authors.initials: DG
authors.lastname: Larsson
authors.affiliation: Zoology Department, College of Science, King Saud University, Riyadh, Saudi Arabia.|A.R. Al-Jeraisy Chair for DNA Research, Zoology Department, College of Science, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Quaiser
authors.initials: Q
authors.lastname: Saquib
authors.affiliation: Botany & Microbiology Department, College of Science, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Hend A
authors.initials: HA
authors.lastname: Alwathnani
authors.affiliation: Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA.
authors.forename: Barry P
authors.initials: BP
authors.lastname: Rosen
authors.affiliation: Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China. ygzhu@iue.ac.cn.
authors.forename: Yong-Guan
authors.initials: YG
authors.lastname: Zhu
authors.affiliation: Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China. rensing@iue.ac.cn.|J. Craig Venter Institute, San Diego, CA, USA. rensing@iue.ac.cn.|Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China. rensing@iue.ac.cn.
authors.forename: Christopher
authors.initials: C
authors.lastname: Rensing
mesh_terms: D001151:Arsenic / Q000378:metabolism* / Q000633:toxicity; D003300:Copper / Q000378:metabolism / Q000633:toxicity; D004023:Dictyostelium / Q000502:physiology*; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D020387:Food Chain; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D050296:Microbial Viability; D009876:Operon; D010957:Plasmids / Q000737:chemistry / Q000378:metabolism
chemical_list: D003300:Copper; D001151:Arsenic
keywords: Arsenic; Grazing; Protist