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Schleucher, Jürgen
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Publications (10 of 70) Show all publications
Spahr, S., Bolotin, J., Schleucher, J., Ehlers, I., von Gunten, U. & Hofstetter, T. B. (2015). Compound-specific carbon, nitrogen, and hydrogen isotope analysis of N-nitrosodimethylamine in aqueous solutions. Analytical Chemistry, 87(5), 2916-2924.
Open this publication in new window or tab >>Compound-specific carbon, nitrogen, and hydrogen isotope analysis of N-nitrosodimethylamine in aqueous solutions
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2015 (English)In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 87, no 5, 2916-2924 p.Article in journal (Refereed) Published
Abstract [en]

Mitigation of N-nitrosodimethylamine (NDMA) and other hazardous water disinfection byproducts (DBP) is currently hampered by a limited understanding of DBP formation mechanisms. Because variations of the stable isotope composition of NDMA can potentially reveal reaction pathways and precursor compounds, we developed a method for the compound-specific isotope analysis (CSIA) of (13)C/(12)C, (15)N/(14)N, and (2)H/(1)H ratios of NDMA by gas chromatography coupled to isotope ratio mass spectrometry (GC/IRMS). Method quantification limits for the accurate isotope analysis of NDMA, N-nitrosodiethyl-, -dipropyl-, and -dibutylamine as well as N-nitrosopyrrolidine were between 0.18 to 0.60 nmol C, 0.40 to 0.80 nmol N, and 2.2 to 5.8 nmol H injected on column. Coupling solid phase extraction (SPE) to GC/IRMS enabled the precise quantification of C, N, and H isotope ratios of NDMA in aqueous samples at concentrations of 0.6 μM (45 μg L(-1)). We validated the proposed method with a laboratory experiment, in which NDMA was formed with stoichiometric yield (97 ± 4%) through chloramination of the pharmaceutical ranitidine (3 μM). δ(13)C and δ(2)H values of NDMA remained constant during NDMA formation while its δ(15)N increased due to a reaction at a N atom in the rate-limiting step of NDMA formation. The δ(2)H value of NDMA determined by SPE-GC/IRMS also corresponded well to the δ(2)H value of the N(CH3)2-group of ranitidine measured by quantitative deuterium nuclear magnetic resonance spectroscopy. This observation implies that the N(CH3)2-moiety of ranitidine is transferred to NDMA without being chemically altered and illustrates the accuracy of the proposed method.

National Category
Analytical Chemistry
Identifiers
urn:nbn:se:umu:diva-101104 (URN)10.1021/ac5044169 (DOI)000350611700057 ()25621380 (PubMedID)
Note

Originally included in thesis in manuscript form, with the title "Compound-Specific Carbon, Nitrogen, and Hydrogen Isotope Analysis of N-Nitrosodimethylamine (NDMA) in Aqueous Solutions"

Available from: 2015-03-20 Created: 2015-03-20 Last updated: 2017-12-04Bibliographically approved
Ehlers, I., Augusti, A., Betson, T. R., Nilsson, M. B., Marshall, J. D. & Schleucher, J. (2015). Detecting long-term metabolic shifts using isotopomers: CO2-driven suppression of photorespiration in C-3 plants over the 20th century. Proceedings of the National Academy of Sciences of the United States of America, 112(51), 15585-15590.
Open this publication in new window or tab >>Detecting long-term metabolic shifts using isotopomers: CO2-driven suppression of photorespiration in C-3 plants over the 20th century
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2015 (English)In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 112, no 51, 15585-15590 p.Article in journal (Refereed) Published
Abstract [en]

Terrestrial vegetation currently absorbs approximately a third of anthropogenic CO2 emissions, mitigating the rise of atmospheric CO2. However, terrestrial net primary production is highly sensitive to atmospheric CO2 levels and associated climatic changes. In C-3 plants, which dominate terrestrial vegetation, net photosynthesis depends on the ratio between photorespiration and gross photosynthesis. This metabolic flux ratio depends strongly on CO2 levels, but changes in this ratio over the past CO2 rise have not been analyzed experimentally. Combining CO2 manipulation experiments and deuterium NMR, we first establish that the intramolecular deuterium distribution (deuterium isotopomers) of photosynthetic C-3 glucose contains a signal of the photorespiration/photosynthesis ratio. By tracing this isotopomer signal in herbarium samples of natural C-3 vascular plant species, crops, and a Sphagnum moss species, we detect a consistent reduction in the photorespiration/photosynthesis ratio in response to the similar to 100-ppm CO2 increase between similar to 1900 and 2013. No difference was detected in the isotopomer trends between beet sugar samples covering the 20th century and CO2 manipulation experiments, suggesting that photosynthetic metabolism in sugar beet has not acclimated to increasing CO2 over >100 y. This provides observational evidence that the reduction of the photorespiration/photosynthesis ratio was ca. 25%. The Sphagnum results are consistent with the observed positive correlations between peat accumulation rates and photosynthetic rates over the Northern Hemisphere. Our results establish that isotopomers of plant archives contain metabolic information covering centuries. Our data provide direct quantitative information on the "CO2 fertilization" effect over decades, thus addressing a major uncertainty in Earth system models.

Keyword
isotopomer, acclimation, deuterium, CO2 fertilization, atmospheric change
National Category
Medical Biotechnology (with a focus on Cell Biology (including Stem Cell Biology), Molecular Biology, Microbiology, Biochemistry or Biopharmacy)
Identifiers
urn:nbn:se:umu:diva-114013 (URN)10.1073/pnas.1504493112 (DOI)000366916000036 ()26644588 (PubMedID)
Available from: 2016-01-21 Created: 2016-01-11 Last updated: 2017-11-30Bibliographically approved
Vestergren, J., Ouattara, K., Schleucher, J., Gröbner, G. & Ilstedt, U. (2014). Effect of Trees on Forms of Soil Phosphorus in an Agroforestry Parkland in Burkina Faso. .
Open this publication in new window or tab >>Effect of Trees on Forms of Soil Phosphorus in an Agroforestry Parkland in Burkina Faso
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2014 (English)Manuscript (preprint) (Other academic)
Abstract [en]

Phosphorus is commonly a limiting nutrient for crop production, especially in highly weathered tropical soils. In two semi-arid areas in Burkina Faso with high and low aluminum and iron content respectively, we studied the effect of scattered trees within cropping fields (an agroforestry system called “parklands”) on soils from two areas with high and low aluminum and iron content, respectively. The study focused on different P forms using liquid-state 31P NMR, and their relation to soil chemical properties, determined by XRF. We hypothesized that i) There is generally a difference in P forms between under canopies and in openings outside canopies due to higher input and turnover of organic material close to trees; ii) Close to trees there are more P forms of microbial origin due to the increased activity of the microbial community; iii) This difference is more pronounced in the area with higher content of aluminum and iron. We took topsoil samples under tree canopies as well as outside tree canopies. Our results showed that there were generally low levels of organic carbon and P, but under the canopies of the scattered trees the levels were higher. 31P-NMR showed that soil P was composed of similar ratios of inorganic and organic P as has been observed in other ecosystems, and that the organic P pool was composed of P species commonly observed in soils. NMR also revealed that areas outside the canopies had a less diverse P composition. In the area with high Al/Fe content, microbial activity under trees had a more pronounced effect on the soil P composition, by significantly increasing the amounts of P species of biological origin. In conclusion, the study confirmed the importance of soil organic matter and trees for P availability in semi-arid tropical ecosystems.

Publisher
58 p.
Keyword
phosphorus, 31P NMR, agroforestry, multivarate, nutrients, sub-sahelian
National Category
Physical Chemistry Geosciences, Multidisciplinary
Research subject
Physical Chemistry
Identifiers
urn:nbn:se:umu:diva-93378 (URN)978-91-7601-132-4 (ISBN)
Available from: 2014-09-19 Created: 2014-09-18 Last updated: 2014-09-30Bibliographically approved
Ehlers, I., Betson, T. R., Vetter, W. & Schleucher, J. (2014). Elucidating Turnover Pathways of Bioactive Small Molecules by Isotopomer Analysis: The Persistent Organic Pollutant DDT. PLoS ONE, 9(10), e110648.
Open this publication in new window or tab >>Elucidating Turnover Pathways of Bioactive Small Molecules by Isotopomer Analysis: The Persistent Organic Pollutant DDT
2014 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 10, e110648- p.Article in journal (Refereed) Published
Abstract [en]

The persistent organic pollutant DDT (1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane) is still indispensable in the fight againstmalaria, although DDT and related compounds  pose toxicological  hazards. Technical DDT contains the dichloro congenerDDD (1-chloro-4-[2,2-dichloro-1-(4-chlorophenyl)ethyl]benzene)   as by-product, but  DDD is also formed by  reductive degradation of DDT in the environment. To differentiate between DDD formation pathways, we applied deuterium NMR spectroscopy to measure intramolecular deuterium distributions (2H isotopomer abundances) of DDT and DDD. DDD formed in the technical  DDT synthesis was strongly deuterium-enriched at one intramolecular position, which we traced back to 2H/1H fractionation of a chlorination step in the technical synthesis.  In contrast, DDD formed by reductive degradation was strongly depleted at the same position, which was due to the incorporation of 2H-depleted hydride equivalents during reductive degradation. Thus, intramolecular isotope distributions give mechanistic information on reaction pathways, and explain a puzzling difference in the whole-molecule 2H/1H ratio between DDT and DDD. In general, our results highlight that intramolecular isotope distributions are essential to interpret whole-molecule isotope ratios. Intramolecular isotope information allows distinguishing pathways of DDD formation, which is important to identify polluters or to assess  DDT turnover in the environment. Because  intramolecular isotope data directly reflect isotope fractionation of individual chemical reactions, they are broadly applicable to elucidate transformation pathways of smallbioactive molecules in chemistry, physiology and environmental science.

Place, publisher, year, edition, pages
PLoS ONE, 2014
Keyword
DDT, turnover pathway, isotopomer, deuterium
National Category
Chemical Sciences
Research subject
Analytical Chemistry
Identifiers
urn:nbn:se:umu:diva-97673 (URN)10.1371/journal.pone.0110648 (DOI)000343943100033 ()
Available from: 2015-01-03 Created: 2015-01-03 Last updated: 2017-12-05Bibliographically approved
Aguilar, X., Blomberg, J., Brännström, K., Olofsson, A., Schleucher, J. & Björklund, S. (2014). Interaction Studies of the Human and Arabidopsis thaliana Med25-ACID Proteins with the Herpes Simplex Virus VP16-and Plant-Specific Dreb2a Transcription Factors. PLoS ONE, 9(5), e98575.
Open this publication in new window or tab >>Interaction Studies of the Human and Arabidopsis thaliana Med25-ACID Proteins with the Herpes Simplex Virus VP16-and Plant-Specific Dreb2a Transcription Factors
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2014 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 5, e98575- p.Article in journal (Refereed) Published
Abstract [en]

Mediator is an evolutionary conserved multi-protein complex present in all eukaryotes. It functions as a transcriptional coregulator by conveying signals from activators and repressors to the RNA polymerase II transcription machinery. The Arabidopsis thaliana Med25 (aMed25) ACtivation Interaction Domain (ACID) interacts with the Dreb2a activator which is involved in plant stress response pathways, while Human Med25-ACID (hMed25) interacts with the herpes simplex virus VP16 activator. Despite low sequence similarity, hMed25-ACID also interacts with the plant-specific Dreb2a transcriptional activator protein. We have used GST pull-down-, surface plasmon resonance-, isothermal titration calorimetry and NMR chemical shift experiments to characterize interactions between Dreb2a and VP16, with the hMed25 and aMed25-ACIDs. We found that VP16 interacts with aMed25-ACID with similar affinity as with hMed25-ACID and that the binding surface on aMed25-ACID overlaps with the binding site for Dreb2a. We also show that the Dreb2a interaction region in hMed25-ACID overlaps with the earlier reported VP16 binding site. In addition, we show that hMed25-ACID/Dreb2a and aMed25-ACID/Dreb2a display similar binding affinities but different binding energetics. Our results therefore indicate that interaction between transcriptional regulators and their target proteins in Mediator are less dependent on the primary sequences in the interaction domains but that these domains fold into similar structures upon interaction.

Keyword
Mediator, Med25, Dreb2a, VP16, conformational changes, NMR, ITC
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-91061 (URN)10.1371/journal.pone.0098575 (DOI)000336790800049 ()
Note

Originally included in thesis in manuscript form.

Available from: 2014-07-11 Created: 2014-07-10 Last updated: 2017-12-05Bibliographically approved
Clementi, E. A., Wilhelm, K. R., Schleucher, J., Morozova-Roche, L. A. & Hakansson, A. P. (2013). A Complex of Equine Lysozyme and Oleic Acid with Bactericidal Activity against Streptococcus pneumoniae. PLoS ONE, 8(11), Article Number: UNSP e80649.
Open this publication in new window or tab >>A Complex of Equine Lysozyme and Oleic Acid with Bactericidal Activity against Streptococcus pneumoniae
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2013 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 11, Article Number: UNSP e80649- p.Article in journal (Refereed) Published
Abstract [en]

HAMLET and ELOA are complexes consisting of oleic acid and two homologous, yet functionally different, proteins with cytotoxic activities against mammalian cells, with HAMLET showing higher tumor cells specificity, possibly due to the difference in propensity for oleic acid binding, as HAMLET binds 5-8 oleic acid molecules per protein molecule and ELOA binds 11-48 oleic acids. HAMLET has been shown to possess bactericidal activity against a number of bacterial species, particularly those with a respiratory tropism, with Streptococcus pneumoniae displaying the greatest degree of sensitivity. We show here that ELOA also displays bactericidal activity against pneumococci, which at lower concentrations shows mechanistic similarities to HAMLET's bactericidal activity. ELOA binds to S. pneumoniae and causes perturbations of the plasma membrane, including depolarization and subsequent rupture, and activates an influx of calcium into the cells. Selective inhibition of calcium channels and sodium/calcium exchange activity significantly diminished ELOA's bactericidal activity, similar to what we have observed with HAMLET. Finally, ELOA-induced death was also accompanied by DNA fragmentation into high molecular weight fragments - an apoptosis-like morphological phenotype that is seen during HAMLET-induced death. Thus, in contrast to different mechanisms of eukaryote cell death induced by ELOA and HAMLET, these complexes are characterized by rather similar activities towards bacteria. Although the majority of these events could be mimicked using oleic acid alone, the concentrations of oleic acid required were significantly higher than those present in the ELOA complex, and for some assays, the results were not identical between oleic acid alone and the ELOA complex. This indicates that the lipid, as a common denominator in both complexes, is an important component for the complexes' bactericidal activities, while the proteins are required both to solubilize and/or present the lipid at the bacterial membrane and likely to confer other and separate functions during the bacterial death.

Place, publisher, year, edition, pages
Public Library of Science, 2013
National Category
Microbiology in the medical area
Identifiers
urn:nbn:se:umu:diva-85303 (URN)10.1371/journal.pone.0080649 (DOI)000327308500164 ()
Funder
NIH (National Institute of Health), F31DC011218Swedish Research Council
Available from: 2014-02-05 Created: 2014-01-31 Last updated: 2018-01-11Bibliographically approved
Schleucher, J., Gröbner, G. & Karlsson, G. (2013). NMR for LifeA national research infrastructure: a new NMR infrastructure provides access to world-class instruments for users from a wide range of research fields.. Kemivärlden biotech / kemisk tidskrift (3), 35-37.
Open this publication in new window or tab >>NMR for LifeA national research infrastructure: a new NMR infrastructure provides access to world-class instruments for users from a wide range of research fields.
2013 (English)In: Kemivärlden biotech / kemisk tidskrift, no 3, 35-37 p.Article in journal (Other academic) Published
Place, publisher, year, edition, pages
Journal of Chemistry and Biotechnology, 2013
National Category
Chemical Sciences
Identifiers
urn:nbn:se:umu:diva-83180 (URN)
Available from: 2013-11-20 Created: 2013-11-20 Last updated: 2014-01-30Bibliographically 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, 501A-502A p.Article 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: 2017-12-06Bibliographically 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
Keyword
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: 2017-01-10Bibliographically approved
Chaintreau, A., Fieber, W., Sommer, H., Gilbert, A., Yamada, K., Yoshida, N., . . . Remaud, G. S. (2013). Site-specific C-13 content by quantitative isotopic C-13 nuclear magnetic resonance spectrometry: a pilot inter-laboratory study. Analytica Chimica Acta, 788, 108-113.
Open this publication in new window or tab >>Site-specific C-13 content by quantitative isotopic C-13 nuclear magnetic resonance spectrometry: a pilot inter-laboratory study
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2013 (English)In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 788, 108-113 p.Article in journal (Refereed) Published
Abstract [en]

Isotopic C-13 NMR spectrometry, which is able to measure intra-molecular C-13 composition, is of emerging demand because of the new information provided by the C-13 site-specific content of a given molecule. A systematic evaluation of instrumental behaviour is of importance to envisage isotopic C-13 NMR as a routine tool. This paper describes the first collaborative study of intra-molecular C-13 composition by NMR. The main goals of the ring test were to establish intra-and inter-variability of the spectrometer response. Eight instruments with different configuration were retained for the exercise on the basis of a qualification test. Reproducibility at the natural abundance of isotopic C-13 NMR was then assessed on vanillin from three different origins associated with specific delta C-13(i) profiles. The standard deviation was, on average, between 0.9 and 1.2 parts per thousand for intra-variability. The highest standard deviation for inter-variability was 2.1%. This is significantly higher than the internal precision but could be considered good in respect of a first ring test on a new analytical method. The standard deviation of delta C-13(i) in vanillin was not homogeneous over the eight carbons, with no trend either for the carbon position or for the configuration of the spectrometer. However, since the repeatability for each instrument was satisfactory, correction factors for each carbon in vanillin could be calculated to harmonize the results.

(C) 2013 Elsevier B.V. All rights reserved.

Keyword
Collaborative study, Quantitative Nuclear Magnetic Resonance spectrometry, Intra molecular C-13 isotope distribution, Vanillin
National Category
Analytical Chemistry
Identifiers
urn:nbn:se:umu:diva-79246 (URN)10.1016/j.aca.2013.06.004 (DOI)000321497700015 ()
Available from: 2013-09-05 Created: 2013-08-13 Last updated: 2017-12-06Bibliographically approved
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