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Persson, Per
Publications (10 of 100) Show all publications
Ramstedt, M., Leone, L., Persson, P. & Shchukarev, A. (2014). Cell wall composition of Bacillus subtilis changes as a function of pH and Zn2+ exposure: insights from cryo-XPS measurements. Langmuir, 30(15), 4367-4374
Open this publication in new window or tab >>Cell wall composition of Bacillus subtilis changes as a function of pH and Zn2+ exposure: insights from cryo-XPS measurements
2014 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 30, no 15, p. 4367-4374Article in journal (Refereed) Published
Abstract [en]

Bacteria play an important role in the biogeochemical cycling of metals in the environment. Consequently, there is an interest to understand how the bacterial surfaces interact with metals in solution and how this affects the bacterial surface. In this work we have used a surface-sensitive analysis technique, cryogenic X-ray photoelectron spectroscopy (cryo-XPS), to monitor the surface of Bacillus subtilis cells as a function of pH and Zn2+ content in saline solution. The objective of the study was twofold: (1) to investigate the agreement between two data treatment methods for XPS, as well as investigate to what extent sample pretreatment may influence XPS data of bacterial samples, and (2) to characterize how the surface chemistry of bacterial cells is influenced by different external conditions. (1) It was found that the two data treatment methods gave rise to comparable results. However, identical samples analyzed fast-frozen or dry exhibited larger differences in surface chemistry, indicating that sample pretreatment can to large extents influence the obtained surface composition of bacterial samples. (2) The bacterial cell wall (in fast-frozen samples) undergoes dramatic compositional changes with pH and with Zn2+ exposure. The compositional changes are interpreted as an adaptive metal resistance response changing the biochemical composition of the bacterial cell wall. These results have implications for how adsorption processes at the surface of bacterial cells are analyzed, understood, modeled, and predicted. 

Keywords
bacteria, cell membranes, photoelectrons, surface chemistry, zinc, analysis techniques, Bacillus subtilis cells, biochemical composition, biogeochemical cycling, cell wall composition, compositional changes, external conditions, sample pretreatment, X-ray photoelectron spectroscopy
National Category
Chemical Sciences
Identifiers
urn:nbn:se:umu:diva-89583 (URN)10.1021/la5002573 (DOI)000334991400021 ()
Available from: 2014-06-04 Created: 2014-06-04 Last updated: 2018-06-07Bibliographically approved
Alessi, D. S., Lezama-Pacheco, J. S., Stubbs, J. E., Janousch, M., Bargar, J. R., Persson, P. & Bernier-Latmani, R. (2014). The product of microbial uranium reduction includes multiple species with U(IV)-phosphate coordination. Geochimica et Cosmochimica Acta, 131, 115-127
Open this publication in new window or tab >>The product of microbial uranium reduction includes multiple species with U(IV)-phosphate coordination
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2014 (English)In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 131, p. 115-127Article in journal (Refereed) Published
Abstract [en]

Until recently, the reduction of U(VI) to U(IV) during bioremediation was assumed to produce solely the sparingly soluble mineral uraninite, UO2(s). However, results from several laboratories reveal other species of U(IV) characterized by the absence of an EXAFS U-U pair correlation (referred to here as noncrystalline U(IV)). Because it lacks the crystalline structure of uraninite, this species is likely to be more labile and susceptible to reoxidation. In the case of single species cultures, analyses of U extended X-ray fine structure (EXAFS) spectra have previously suggested U(IV) coordination to carboxyl, phosphoryl or carbonate groups. In spite of this evidence, little is understood about the species that make up noncrystalline U(IV), their structural chemistry and the nature of the U(IV)-ligand interactions. Here, we use infrared spectroscopy (IR), uranium L-III-edge X-ray absorption spectroscopy (XAS), and phosphorus K-edge XAS analyses to constrain the binding environments of phosphate and uranium associated with Shewanella oneidensis MR-1 bacterial cells. Systems tested as a function of pH included: cells under metal-reducing conditions without uranium, cells under reducing conditions that produced primarily uraninite, and cells under reducing conditions that produced primarily biomass-associated noncrystalline U(IV). P X-ray absorption near-edge structure (XANES) results provided clear and direct evidence of U(IV) coordination to phosphate. Infrared (IR) spectroscopy revealed a pronounced perturbation of phosphate functional groups in the presence of uranium. Analysis of these data provides evidence that U(IV) is coordinated to a range of phosphate species, including monomers and polymerized networks. U EXAFS analyses and a chemical extraction measurements support these conclusions. The results of this study provide new insights into the binding mechanisms of biomass-associated U(IV) species which in turn sheds light on the mechanisms of biological U(VI) reduction. (C) 2014 Elsevier Ltd. All rights reserved.

National Category
Chemical Sciences
Identifiers
urn:nbn:se:umu:diva-88267 (URN)10.1016/j.gca.2014.01.005 (DOI)000333330100008 ()
Available from: 2014-05-05 Created: 2014-04-29 Last updated: 2018-06-07Bibliographically approved
Sundman, A., Karlsson, T., Laudon, H. & Persson, P. (2014). XAS study of iron speciation in soils and waters from a boreal catchment. Chemical Geology, 364, 93-102
Open this publication in new window or tab >>XAS study of iron speciation in soils and waters from a boreal catchment
2014 (English)In: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 364, p. 93-102Article in journal (Refereed) Published
Abstract [en]

Iron (Fe) is a key element, strongly influencing the biogeochemistry of soils, sediments and waters, but the knowledge about the variety of Fe species present in these systems is still limited. In this work we have used X-ray absorption spectroscopy (XAS) to study the speciation of Fe in soils and waters from a boreal catchment in northern Sweden. The aim was to better understand the controls of Fe speciation across different, but adjacent landscape elements including soil, soil solution, groundwater and stream water draining catchments with contrasting land characteristics. Our results showed that all samples contained mixtures of Fe(II) and Fe(III). The soils consisted of Fe phyllosilicates, Fe (hydr)oxides and Fe complexed by natural organic matter (NOM). All aqueous samples contained Fe(II)– and Fe(III)–NOM complexes, often in combination with Fe(III) (hydr)oxides that were associated with NOM. The variation in contribution from Fe–NOM and Fe (hydr)oxides was controlled by pH and total concentrations of NOM. The XAS spectra suggested formation of mononuclear Fe–NOM complexes consisting of chelate ring structures, but it could not be determined whether they originated solely from Fe(III)– or from a mixture of Fe(II)/Fe(III)–NOM complexes. Our collective results showed that the Fe speciation was highly variable across the different landscape elements and streams. This variation was manifested both in the distribution between mononuclear Fe–NOM complexes and Fe (hydr)oxides associated with NOM and between Fe(II) and Fe(III). These results highlight the complexity of Fe speciation in natural environmental systems and thus the challenges in interpreting Fe reactivity.

Place, publisher, year, edition, pages
Elsevier, 2014
Keywords
Fe speciation, XAS, Stream water, soil solutions, Ground water, Krycklan catchment
National Category
Chemical Sciences Geochemistry Geophysics
Identifiers
urn:nbn:se:umu:diva-85430 (URN)10.1016/j.chemgeo.2013.11.023 (DOI)000329409600009 ()
Funder
NIH (National Institute of Health)
Available from: 2014-02-04 Created: 2014-02-04 Last updated: 2018-06-08Bibliographically approved
Mäkie, P., Persson, P. & Österlund, L. (2013). Adsorption of trimethyl phosphate and triethyl phosphate on dry and water pre-covered hematite, maghemite, and goethite nanoparticles. Journal of Colloid and Interface Science, 392, 349-358
Open this publication in new window or tab >>Adsorption of trimethyl phosphate and triethyl phosphate on dry and water pre-covered hematite, maghemite, and goethite nanoparticles
2013 (English)In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 392, p. 349-358Article in journal (Refereed) Published
Abstract [en]

Adsorption of trimethyl phosphate (TMP) and triethyl phosphate (TEP) on well-characterized nanoparticles of hematite (α-Fe(2)O(3)), maghemite (γ-Fe(2)O(3)), and goethite (α-FeOOH) has been studied by in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), 2D correlation DRIFTS analysis, and X-ray photoelectron spectroscopy (XPS) on dry and water pre-covered surfaces. It is shown that, at room temperature and low coverage, both TMP and TEP coordinate to Lewis acid Fe sites through the O phosphoryl atom on hematite and maghemite, while hydrogen bonding to Brønstedt acid surface OH groups dominates on goethite. At room temperature, slow dissociation of TMP occurs on the iron (hydr)oxide nanoparticles, whereby a methoxy group is displaced to form surface methoxy, leaving adsorbed dimethyl phosphate (DMP). Methoxy is further decomposed to formate, suggesting an oxidative degradation pathway in synthetic air on the oxide particles. Relatively, larger amounts of DMP and surface methoxy form on maghemite, while more formate is produced on hematite. Upon TMP adsorption on dry goethite nanoparticles, no oxidation surface products were detected. Instead, a slow TMP hydrolysis pathway is observed, yielding orthophosphate. It is found that pre-adsorbed water stimulates the hydrolysis of TMP. In contrast to TMP, TEP adsorbs molecularly on all iron hydr(oxide) nanoparticles. This is attributed to the longer aliphatic chain, which stabilizes the loss of charge on the methoxy CO bonds by charge redistribution upon phosphoryl O coordination to Fe surface atoms. The presented results implicate different reactivity depending on specific molecular structure of the organophosphorus compound (larger functional groups can compensate loss of charge due to surface coordination) and iron (hydr)oxide surface structure (exposing Lewis acid or Brønstedt acid sites).

Place, publisher, year, edition, pages
Elsevier, 2013
Keywords
Adsorption, Trimethyl phosphate, Triethyl phosphate, Hematite, Maghemite, Goethite, Diffuse reflectance infrared Fourier transform spectroscopy, X-ray photoelectron spectroscopy
National Category
Physical Chemistry
Identifiers
urn:nbn:se:umu:diva-62029 (URN)10.1016/j.jcis.2012.10.012 (DOI)000314136800047 ()23142013 (PubMedID)
Available from: 2012-12-04 Created: 2012-12-04 Last updated: 2018-06-08Bibliographically approved
Sundman, A., Karlsson, T. & Persson, P. (2013). An experimental protocol for structural characterization of Fe in dilute natural waters. Environmental Science and Technology, 47(15), 8557-8564
Open this publication in new window or tab >>An experimental protocol for structural characterization of Fe in dilute natural waters
2013 (English)In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 47, no 15, p. 8557-8564Article in journal (Refereed) Published
Abstract [en]

The properties of iron (Fe) complexes and compounds in the environment influence several central processes, e.g., iron uptake, adsorption/desorption of contaminants and nutrients, and redox transformations, as well as the fate of of natural organic matter (NOM). It is thus important to characterize Fe species in environmental samples. Synchrotron-based extended X-ray absorption fine structure (EXAFS) spectroscopy has been used in several studies on soils and sediments, but literature is scarce on investigations of natural waters because of low Fe concentrations. In this study we have described a gentle and noninvasive preconcentration method, based on electrostatic adsorption onto ion-exchange resins, suitable for EXAFS analysis of Fe species in dilute stream water samples. The EXAFS results of metal-organic model complexes showed that no significant local structural distortions were induced by the method. We also demonstrated the feasibility for an 8 μM Fe stream water sample. The Fe heterogeneity in this stream water was investigated via a gradient series at 28%, 42%, 77%, 84%, and 100% adsorption of total iron. The EXAFS results showed that Fe(III) in this stream water was divided into Fe(III)-NOM complexes and Fe(III) (oxyhydr)oxides associated with NOM, and that each class consisted of several subspecies.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2013
Keywords
Saccharification, Enzymatic hydrolysis, Cellulase; Cellulose, Reducing agents
National Category
Chemical Sciences Environmental Sciences
Identifiers
urn:nbn:se:umu:diva-80680 (URN)10.1021/es304630a (DOI)000323013400059 ()23815564 (PubMedID)
Available from: 2013-09-23 Created: 2013-09-23 Last updated: 2018-06-08Bibliographically approved
Rineau, F., Shah, F., Smits, M. M., Persson, P., Johansson, T., Carleer, R., . . . Tunlid, A. (2013). Carbon availability triggers the decomposition of plant litter and assimilation of nitrogen by an ectomycorrhizal fungus. The ISME Journal, 7(10), 2010-2022
Open this publication in new window or tab >>Carbon availability triggers the decomposition of plant litter and assimilation of nitrogen by an ectomycorrhizal fungus
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2013 (English)In: The ISME Journal, ISSN 1751-7362, E-ISSN 1751-7370, Vol. 7, no 10, p. 2010-2022Article in journal (Refereed) Published
Abstract [en]

The majority of nitrogen in forest soils is found in organic matter-protein complexes. Ectomycorrhizal fungi (EMF) are thought to have a key role in decomposing and mobilizing nitrogen from such complexes. However, little is known about the mechanisms governing these processes, how they are regulated by the carbon in the host plant and the availability of more easily available forms of nitrogen sources. Here we used spectroscopic analyses and transcriptome profiling to examine how the presence or absence of glucose and/or ammonium regulates decomposition of litter material and nitrogen mobilization by the ectomycorrhizal fungus Paxillus involutus. We found that the assimilation of nitrogen and the decomposition of the litter material are triggered by the addition of glucose. Glucose addition also resulted in upregulation of the expression of genes encoding enzymes involved in oxidative degradation of polysaccharides and polyphenols, peptidases, nitrogen transporters and enzymes in pathways of the nitrogen and carbon metabolism. In contrast, the addition of ammonium to organic matter had relatively minor effects on the expression of transcripts and the decomposition of litter material, occurring only when glucose was present. On the basis of spectroscopic analyses, three major types of chemical modifications of the litter material were observed, each correlated with the expression of specific sets of genes encoding extracellular enzymes. Our data suggest that the expression of the decomposition and nitrogen assimilation processes of EMF can be tightly regulated by the host carbon supply and that the availability of inorganic nitrogen as such has limited effects on saprotrophic activities.

Keywords
carbon and nitrogen cycling, ectomycorrhiza, nitrogen assimilation, organic matter degradation, carbon availability
National Category
Chemical Sciences
Identifiers
urn:nbn:se:umu:diva-82283 (URN)10.1038/ismej.2013.91 (DOI)000324869400012 ()
Available from: 2014-02-18 Created: 2013-10-29 Last updated: 2018-06-08Bibliographically approved
Cunningham, L., Vogel, H., Nowaczyk, N., Wennrich, V., Juschus, O., Persson, P. & Rosen, P. (2013). Climatic variability during the last interglacial inferred from geochemical proxies in the Lake El'gygytgyn sediment record. Palaeogeography, Palaeoclimatology, Palaeoecology, 386, 408-414
Open this publication in new window or tab >>Climatic variability during the last interglacial inferred from geochemical proxies in the Lake El'gygytgyn sediment record
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2013 (English)In: Palaeogeography, Palaeoclimatology, Palaeoecology, ISSN 0031-0182, E-ISSN 1872-616X, Vol. 386, p. 408-414Article in journal (Refereed) Published
Abstract [en]

The Last Interglacial Period (LIP) is often regarded as a good analogue for potential climatic conditions under predicted global warming scenarios. Despite this, there is still debate over the nature, duration and frequency of climatic changes during this period. One particularly contentious issue has been the apparent evidence of climatic instability identified in many marine cores but seemingly lacking from many terrestrial archives, especially within the Arctic, a key region for global climate change research. In this paper, geochemical records from Lake El'gygytgyn, north-eastern Russia, are used to infer past climatic changes during the LIP from within the high Arctic. With a sampling resolution of similar to 20-similar to 90 years, these records offer the potential for detailed, high-resolution palaeoclimate reconstruction. This study shows that the LIP commenced in central Chukotka similar to 129 thousand years ago (ka), with the warmest climatic conditions occurring between similar to 128 and 127 ka before being interrupted by a short-lived cold reversal. Mild climatic conditions then persisted until similar to 122 ka when a marked reduction in the sedimentation rate suggests a decrease in precipitation. A further climatic deterioration at similar to 118 ka marks the return to glacial conditions. This study highlights the value of incorporating several geochemical proxies when inferring past climatic conditions, thus providing the potential to identify signals related to environmental change within the catchment. We also demonstrate the importance of considering how changes in sedimentation rate influence proxy records, in order to develop robust palaeoenvironmental reconstructions. (C) 2013 Elsevier B.V. All rights reserved.

Place, publisher, year, edition, pages
Elsevier, 2013
Keywords
Palaeolimnology, Climate change, Far-eastern Arctic Russia, Primary productivity, Glacial termination, Last interglacial period
National Category
Geophysics Geosciences, Multidisciplinary
Identifiers
urn:nbn:se:umu:diva-82824 (URN)10.1016/j.palaeo.2013.06.009 (DOI)000324848800031 ()
Funder
FormasSwedish Research Council
Available from: 2013-11-11 Created: 2013-11-11 Last updated: 2018-06-08Bibliographically approved
Vestergren, J. E., Vincent, A. G., Persson, P., Jansson, M., Ilstedt, U., Giesler, R., . . . Gröbner, G. (2013). Novel Approaches for Identifying Phosphorus Species in Terrestrial and Aquatic Ecosystems with P-31 NMR. Paper presented at 57th Annual Meeting of the Biophysical-Society, FEB 02-06, 2013, Philadelphia, PA. Biophysical Journal, 104(2), 501A-502A
Open this publication in new window or tab >>Novel Approaches for Identifying Phosphorus Species in Terrestrial and Aquatic Ecosystems with P-31 NMR
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2013 (English)In: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 104, no 2, p. 501A-502AArticle in journal, Meeting abstract (Other academic) Published
National Category
Biophysics
Identifiers
urn:nbn:se:umu:diva-68922 (URN)000316074305050 ()
Conference
57th Annual Meeting of the Biophysical-Society, FEB 02-06, 2013, Philadelphia, PA
Available from: 2013-05-02 Created: 2013-04-29 Last updated: 2018-06-08Bibliographically approved
Vincent, A. G., Ilstedt, U., Vestergren, J., Giesler, R., Persson, P., Gröbner, G. & Schleucher, J. (2013). Phosphorus in forest soils: disentangling the chemistry of an essential nutrient. Forest facts (4)
Open this publication in new window or tab >>Phosphorus in forest soils: disentangling the chemistry of an essential nutrient
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2013 (English)In: Forest facts, no 4Article in journal (Refereed) Published
Place, publisher, year, edition, pages
SLU, 2013
Keywords
Phosphorus, forests, soil, nutrients, nuclear magnetic resonance (NMR), spectroscopy
National Category
Forest Science
Identifiers
urn:nbn:se:umu:diva-71209 (URN)
Available from: 2013-05-23 Created: 2013-05-23 Last updated: 2018-06-08Bibliographically approved
Vincent, A. G., Vestergren, J., Gröbner, G., Persson, P., Schleucher, J. & Giesler, R. (2013). Soil organic phosphorus transformations in a boreal forest chronosequence. Plant and Soil, 367(1-2), 149-162
Open this publication in new window or tab >>Soil organic phosphorus transformations in a boreal forest chronosequence
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2013 (English)In: Plant and Soil, ISSN 0032-079X, E-ISSN 1573-5036, Vol. 367, no 1-2, p. 149-162Article in journal (Refereed) Published
Abstract [en]

Background and Aims Soil phosphorus (P) composition changes with ecosystem development, leading to changes in P bioavailability and ecosystem properties. Little is known, however, about how soil P transformations proceed with ecosystem development in boreal regions.

Methods We used 1-dimensional 31P and 2-dimensional 1H, 31P correlation nuclear magnetic resonance (NMR) spectroscopy to characterise soil organic P transformations in humus horizons across a 7,800 year-old chronosequence in Västerbotten, northern Sweden.

Results Total soil P concentration varied little along the chronosequence, but P compounds followed three trends. Firstly, the concentrations of DNA, 2-aminoethyl phosphonic acid, and polyphosphate, increased up to 1,200–2,700 years and then declined. Secondly, the abundances of α– and β—glycerophosphate, nucleotides, and pyrophosphate, were higher at the youngest site compared with all other sites. Lastly, concentrations of inositol hexakisphosphate fluctuated with site age. The largest changes in soil P composition tended to occur in young sites which also experience the largest shifts in plant community composition.

Conclusions The apparent lack of change in total soil P is consistent with the youth and nitrogen limited nature of the Västerbotten chronosequence. Based on 2D NMR spectra, around 40 % of extractable soil organic P appeared to occur in live microbial cells. The observed trends in soil organic P may be related to shifts in plant community composition (and associated changes in soil microorganisms) along the studied chronosequence, but further studies are needed to confirm this.

Place, publisher, year, edition, pages
Dordrecht: Springer, 2013
Keywords
Podzolization, 1D 31P NMR, 2D 1H, 31P correlation NMR, Inositol hexakisphosphate, Ribonucleic acid (RNA), Västerbotten chronosequence
National Category
Chemical Sciences
Identifiers
urn:nbn:se:umu:diva-71214 (URN)10.1007/s11104-013-1731-z (DOI)000319771700010 ()
Available from: 2013-05-23 Created: 2013-05-23 Last updated: 2018-06-08Bibliographically approved
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