The microbial impact on the sorption behaviour of selenite in an acidic, nutrient-poor boreal bog

Lusa, Merja; Bomberg, Malin; Aromaa, Hanna; Knuutinen, Jenna Janina; Lehto, Jukka

doi:10.1016/j.jenvrad.2015.05.014

Cited by 13 publications

(14 citation statements)

References 54 publications

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“…We have previously shown that the Pseudomonas sp. strain T5-6-I used in this study was able to remove Se(IV) from nutrient solutions depending on incubation time and temperature (Lusa et al 2015). We also observed intracellular Se-aggregates using TEM and EDX after Se(IV) exposure in this bacterium and concluded that accumulation and transport was likely metabolism-dependent and suggested two different transport mechanisms for Se(IV) uptake: (1) A low affinity transport system up-regulated by NO 3 − , NO 2 − or SO 4 2− , and (2) a Se(IV) regulated transport system (Lusa et al 2017).…”

Section: Discussionmentioning

confidence: 99%

“…Previously, we found that bacteria affected selenium behavior and retention in boreal bog environment and that the Pseudomonas sp. strain (T5-6-I) (Lusa et al 2016), which was also used in the present study, removed 75 Se(IV) from solutions under different nutrient conditions (Lusa et al 2015). In experiments with stable Se isotopes, brick-red reduced elemental selenium (Se 0 ) was formed from both Se(IV) and Se(VI) in incubations with the Pseudomonas sp.…”

Section: Introductionmentioning

confidence: 93%

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The reduction of selenium(IV) by boreal Pseudomonas sp. strain T5-6-I – Effects on selenium(IV) uptake in Brassica oleracea

Lusa

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Honkanen

et al. 2019

Environmental Research

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Selenium (Se) is an essential micronutrient but toxic when taken in excessive amounts. Therefore, understanding the metabolic processes related to selenium uptake and bacteria-plant interactions coupled with selenium metabolism are of high importance. We cultivated Brassica oleracea with the previously isolated heterotrophic aerobic Se(IV)-reducing Pseudomonas sp. T5-6-I strain to better understand the phenomena of bacteria-mediated Se(IV) reduction on selenium availability to the plants. B. oleracea grown on Murashige and Skoog medium (MS-salt agar) with and without of Pseudomonas sp. were amended with Se(IV)/ 75 Se(IV), and selenium transfer into plants was studied using autoradiography and gamma spectroscopy. XANES was in addition used to study the speciation of selenium in the B. oleracea plants. In addition, the effects of Se(IV) on the protein expression in B. oleracea was studied using HPLC-SEC. TEM and confocal microscopy were used to follow the bacterial/Se-aggregate accumulation in plants and the effects of bacterial inoculation on root-hair growth. In the tests using 75 Se(IV) on average 130% more selenium was translocated to the B. oleracea plants grown with Pseudomonas sp. compared to the plants grown with selenium, but without Pseudomonas sp.. In addition, these bacteria notably increased root hair density. Changes in the protein expression of B. oleracea were observed on the ~30 -58 kDa regions in the Se(IV) treated samples, probably connected e.g. to the oxidative stress induced by Se(IV) or expression of proteins connected to the Se(IV) metabolism. Based on the XANES measurements, selenium appears to accumulate in B. oleracea mainly in organic C-Se-H and C-Se-C bonds with and without bacteria inoculation. We conclude that the Pseudomonas sp. T5-6-I strain seems to contribute positively to the selenium accumulation in plants, establishing the high potential of Se 0 -producing bacteria in the use of phytoremediation and biofortification of selenium.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 93%

The reduction of selenium(IV) by boreal Pseudomonas sp. strain T5-6-I – Effects on selenium(IV) uptake in Brassica oleracea

Lusa

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Honkanen

et al. 2019

Environmental Research

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“…Previously, we found the two heterotrophic aerobic Pseudomonas strains, used in this study, to remove 75 Se(IV)O 3 2− from solutions under different nutrient conditions [28]. In this study, the factors affecting the uptake and reduction of Se oxyanions by these two Pseudomonas strains, PS-0-L and T5-6-I isolated from a boreal bog environment [29], was examined using batch experiments, transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX).…”

Section: Introductionmentioning

confidence: 92%

Uptake and reduction of Se(IV) in two heterotrophic aerobic <em>Pseudomonads</em> strains isolated from boreal bog environment

2017

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Selenite (Se(IV), SeO 3 2− ) uptake and the effect of selenite supplement on protein synthesis was investigated in two Pseudomonas sp. strains isolated from a boreal bog. These aerobic bacteria efficiently reduced Se(IV) with intracellular reduced Se 0 observed in the cytoplasm under dark aerobic conditions. The proteome analysis of Se(IV) supplement and temperature responses by SDS-PAGE gel electrophoresis showed variations in the protein expression on the 40–60 kDa regions following these stress factors, probably through enzymes associated to oxidative stress or temperature adaptation. NO 3 − /NO 2 − /SO 4 2− addition enhanced Se(IV) uptake in both bacteria, but Se(IV) uptake sustained also under sulphur and nitrogen starvation. Our findings suggest two different transport mechanisms for Se(IV) uptake in these Pseudomonas sp. strains; a low affinity transport system up-regulated by NO 3 − /NO 2 − /SO 4 2− and a distinct Se(IV)O 3 2− regulated transport system. Following transport, Se(IV) is reduced in the cytoplasm, forming Se 0 granules, visible in TEM and verified using EDX.

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“…The sampling site, Lastensuo bog, is located about 25 km west from the Olkiluoto Island. This area has been used as a reference site for the spent nuclear fuel disposal research, representing boreal ombrotrophic bog (e.g., Mäkilä and Grundström, 2008; Lusa et al, 2015a,b,c, 2016a,b). Lastensuo is a raised bog/hummock–hollow pine bog (Mäkilä and Grundström, 2008), with an area of 4.4 km 2 and the average depth of 6.3 m (Mäkilä and Grundström, 2008).…”

Section: Methodsmentioning

confidence: 99%

Ni(II) Interactions in Boreal Paenibacillus sp., Methylobacterium sp., Paraburkholderia sp., and Pseudomonas sp. Strains Isolated From an Acidic, Ombrotrophic Bog

et al. 2019

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The uptake of nickel [Ni(II)] by Paenibacillus sp., Methylobacterium sp., Paraburkholderia sp., and Pseudomonas sp. strains isolated from a boreal bog was studied using batch experiments. All strains removed Ni(II) from the solution and the uptake efficiency was affected by the nutrient source, incubation temperature, time, and pH. As highest Ni uptake (with a maximum Kd of 1890 L/kg DW) was recorded for the Pseudomonas sp. strains, these bacteria were used in the following protein expression (SDS-PAGE and MALDI-TOFF), transmission electron microscopy (TEM) and EDS experiments. In addition, Freundlich and Langmuir sorption isotherms were determined. In the Ni(II) treated cells, dense crystalline intra-cellular accumulations were observed in TEM examinations, which were identified as Ni accumulations using EDS. SDS-PAGE and MALDI-TOFF spectra of Ni(II) treated cells showed several changes in the protein profiles, which can indicate active accumulation of Ni in these bacteria. Concurrently, we observed Ni(II) uptake to follow Freundlich and Langmuir isotherms, suggesting straight cellular biosorption in addition to the intra-cellular accumulation. The role of cellular (cell membrane and cell wall) functional groups involved in Ni(II) binding were therefore studied using Fourier transformation infrared spectroscopy. These analyses supported the potential role of the alcoholic hydroxyl, carboxyl and amine groups in Ni(II) binding in these bacteria, therefore suggesting two different Ni(II) uptake mechanisms; (i) intra-cellular accumulation [possibly connected to detoxification of Ni(II)], and (ii) straight biosorption on cell membrane/wall functional groups.

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The microbial impact on the sorption behaviour of selenite in an acidic, nutrient-poor boreal bog

Cited by 13 publications

References 54 publications

The reduction of selenium(IV) by boreal Pseudomonas sp. strain T5-6-I – Effects on selenium(IV) uptake in Brassica oleracea

The reduction of selenium(IV) by boreal Pseudomonas sp. strain T5-6-I – Effects on selenium(IV) uptake in Brassica oleracea

Uptake and reduction of Se(IV) in two heterotrophic aerobic <em>Pseudomonads</em> strains isolated from boreal bog environment

Ni(II) Interactions in Boreal Paenibacillus sp., Methylobacterium sp., Paraburkholderia sp., and Pseudomonas sp. Strains Isolated From an Acidic, Ombrotrophic Bog

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