Open AccessDissimilatory arsenate reductase activity and arsenate‐respiring bacteria in bovine rumen fluid, hamster feces, and the termite hindgut
Author(s) -
Herbel Mitchell J.,
Switzer Blum Jodi,
Hoeft Shelley E.,
Cohen Samuel M.,
Arnold Lora L.,
Lisak Joy,
Stolz John F.,
Oremland Ronald S.
Publication year - 2002
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/j.1574-6941.2002.tb00966.x
Subject(s) - arsenate , biology , arsenite , microbiology and biotechnology , rumen , hindgut , arsenic , feces , population , biochemistry , chemistry , botany , fermentation , demography , organic chemistry , sociology , larva , midgut
Bovine rumen fluid and slurried hamster feces completely reduced millimolar levels of arsenate to arsenite upon incubation under anoxic conditions. This activity was strongly inhibited by autoclaving or aerobic conditions, and partially inhibited by tungstate or chloramphenicol. The rate of arsenate reduction was faster in feces from a population of arsenate‐watered (100 ppm) hamsters compared to a control group watered without arsenate. Using radioisotope methods, arsenate reductase activity in hamster feces was also detected at very low concentrations of added arsenate (∼10 μM). Bacterial cultures were isolated from these materials, as well as from the termite hindgut, that grew using H 2 as their electron donor, acetate as their carbon source, and arsenate as their respiratory electron acceptor. The three cultures aligned phylogenetically either with well‐established enteric bacteria, or with an organism associated with feedlot fecal wastes. Because arsenite is transported across the gut epithelium more readily than arsenate, microbial dissimilatory reduction of arsenate in the gut may promote the body's absorption of arsenic and hence potentiate its toxicity.