Selenium Metabolism in Prokaryotes

Rother, Michael

doi:10.1007/978-1-4614-1025-6_36

Cited by 9 publications

(7 citation statements)

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“…In some bacterial strains, elemental SeNPs were observed both inside and outside of cells [ 12 ],[ 21 ],[ 32 ],[ 33 ] whereas in other bacteria nanoparticles were only observed outside of cells [ 20 ]. We did not detect Se(IV) by HPLC-HG-AFS in cellular fractions (data not shown) although elemental Se less than 0.1 μM meets the demand of bacteria for synthesis of selenocysteine [ 34 ]. We could not observe SeNPs produced inside of cells at log phase and stationary phase by TEM, EDX and EDS Elemental Mapping (Figures 3 , 4 and Additional file 1 : Figure S1) although SeNPs were easily observed by TEM in many bacterial cells [ 12 ],[ 21 ],[ 32 ].…”

Section: Discussionmentioning

confidence: 99%

Selenite reduction by the obligate aerobic bacterium Comamonas testosteroni S44 isolated from a metal-contaminated soil

Zheng

Wang

et al. 2014

BMC Microbiol

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BackgroundSelenium (Se) is an essential trace element in most organisms but has to be carefully handled since there is a thin line between beneficial and toxic concentrations. Many bacteria have the ability to reduce selenite (Se(IV)) and (or) selenate (Se(VI)) to red elemental selenium that is less toxic.ResultsA strictly aerobic bacterium, Comamonas testosteroni S44, previously isolated from metal(loid)-contaminated soil in southern China, reduced Se(IV) to red selenium nanoparticles (SeNPs) with sizes ranging from 100 to 200 nm. Both energy dispersive X-ray Spectroscopy (EDX or EDS) and EDS Elemental Mapping showed no element Se and SeNPs were produced inside cells whereas Se(IV) was reduced to red-colored selenium in the cytoplasmic fraction in presence of NADPH. Tungstate inhibited Se(VI) but not Se(IV) reduction, indicating the Se(IV)-reducing determinant does not contain molybdenum as co-factor. Strain S44 was resistant to multiple heavy and transition metal(loid)s such as Se(IV), As(III), Cu(II), and Cd(II) with minimal inhibitory concentrations (MIC) of 100 mM, 20 mM, 4 mM, and 0.5 mM, respectively. Disruption of iscR encoding a transcriptional regulator negatively impacted cellular growth and subsequent resistance to multiple heavy metal(loid)s.ConclusionsC. testosteroni S44 could be very useful for bioremediation in heavy metal(loid) polluted soils due to the ability to both reduce toxic Se(VI) and Se(IV) to non-toxic Se (0) under aerobic conditions and to tolerate multiple heavy and transition metals. IscR appears to be an activator to regulate genes involved in resistance to heavy or transition metal(loid)s but not for genes responsible for Se(IV) reduction.

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Section: Discussionmentioning

confidence: 99%

Selenite reduction by the obligate aerobic bacterium Comamonas testosteroni S44 isolated from a metal-contaminated soil

Zheng

Wang

et al. 2014

BMC Microbiol

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“…Selenium substitutes sulfur in cysteine and methionine in the bacterial proteins to form selenocysteine and selenomethionine [25]. The obtained organic selenium was mainly found in the catalytic site of several known redoxactive enzymes as non-covalently attached cofactors [18].…”

Section: Selenium Biotransformation By P Acidilacticimentioning

confidence: 99%

Effect of sodium selenite on the bacteria growth, selenium accumulation, and selenium biotransformation in Pediococcus acidilactici

Kousha

Yeganeh

Amirkolaie

2017

Food Sci Biotechnol

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In this study, the effect of low selenium concentrations on bacteria growth, selenium bioaccumulation, and selenium speciation in was investigated. Six different sodium selenite (NaSeO) solutions with concentrations of 0, 0.5, 1, 2, 3, and 4 mg/L were added in MRS broth for 24 h. Then, the obtained bacterial pellets were weighed. The contents of total selenium and selenium species in the bacterial pellets were measured via optimized enzymatic hydrolysis and HPLC-ICP-MS. The maximum dried biomass of 1.44 g/L was achieved by utilizing 1 mg/L NaSeO. By increasing sodium selenite concentrations, total selenium contents were significantly increased from 0.14 to 1.45 mg/g dry weight ( < 0.05). The findings indicated that selenium was favorably incorporated into the bacteria protein fraction and mainly formed selenocysteine. Therefore, selenium-enriched lactic acid bacterium can deliver a less-toxic, more bioavailable selenium source for human and animal nutrition.

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“…Selenium in organic compounds is mainly under the -II oxidation state (Rother, 2012). Evidence from sediments collected in the NW Pacific show that Se deposited at the seafloor as organic Se remains largely bound to organic matter throughout early diagenesis (Sokolova and Pilipchuck, 1973).…”

Section: Introductionmentioning

confidence: 98%