| 1. |
- Fan, Lichao, et al.
(author)
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Active metabolic pathways of anaerobic methane oxidation in paddy soils
- 2021
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In: Soil Biology and Biochemistry. - : Elsevier BV. - 0038-0717 .- 1879-3428. ; 156
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Journal article (peer-reviewed)abstract
- Anaerobic oxidation of methane (AOM) is a globally important CH4 sink. However, the AOM pathways in paddy soils, the largest agricultural source of methane emissions (31 Mio tons per year) are not yet well described. Here, a combination of C-13 isotope tracer, phospholipid fatty acids (PLFA) analyses, and microbial community analysis was used to identify AOM pathways in fertilized (pig manure, biochar, NPK, and the control) paddy soils amended with alternative electron acceptors (AEAs) (NO3-, Fe3+, SO42-, humic acids, and the reference without AEAs addition). After 84 days of anaerobic incubation, the microbial co-occurrence network got tightened and became more complex relative to unincubated samples. Fertilization and AEAs addition led to a strong divergence of the microbial community structure as indicated by abundances of AOM-related microbiota and C-13 incorporation into microbial PLFA, thus suggesting an environmental niche differentiation of AOM-involved microorganisms. Comparative analyses revealed a set of major and minor AOM pathways with synergistic relations to complementary anaerobic microbial groups. NO3--driven AOM, performed by members of the candidate group ANME-2d, was the major AOM pathway. Minor AOM pathways involved NO2- reduction by NC10, reduction of humic acids and Fe3+ by Geobacter species, and SO42- reduction by sulfate-reducing bacteria linked with anaerobic methanotrophs. As identified by the network analysis, these active AOM pathways compensated a fraction of CH4 produced during ongoing methanogenesis. From a broader ecological perspective, nitrogendriven AOM will become a more important methane sink in the future with the increases of nitrogen fertilization and deposition.
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| 2. |
- Kalman, Janos L, et al.
(author)
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Investigating polygenic burden in age at disease onset in bipolar disorder: Findings from an international multicentric study.
- 2019
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In: Bipolar disorders. - : Wiley. - 1399-5618 .- 1398-5647. ; 21:1, s. 68-75
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Journal article (peer-reviewed)abstract
- Bipolar disorder (BD) with early disease onset is associated with an unfavorable clinical outcome and constitutes a clinically and biologically homogenous subgroup within the heterogeneous BD spectrum. Previous studies have found an accumulation of early age at onset (AAO) in BD families and have therefore hypothesized that there is a larger genetic contribution to the early-onset cases than to late onset BD. To investigate the genetic background of this subphenotype, we evaluated whether an increased polygenic burden of BD- and schizophrenia (SCZ)-associated risk variants is associated with an earlier AAO in BD patients.A total of 1995 BD type 1 patients from the Consortium of Lithium Genetics (ConLiGen), PsyCourse and Bonn-Mannheim samples were genotyped and their BD and SCZ polygenic risk scores (PRSs) were calculated using the summary statistics of the Psychiatric Genomics Consortium as a training data set. AAO was either separated into onset groups of clinical interest (childhood and adolescence [≤18years] vs adulthood [>18years]) or considered as a continuous measure. The associations between BD- and SCZ-PRSs and AAO were evaluated with regression models.BD- and SCZ-PRSs were not significantly associated with age at disease onset. Results remained the same when analyses were stratified by site of recruitment.The current study is the largest conducted so far to investigate the association between the cumulative BD and SCZ polygenic risk and AAO in BD patients. The reported negative results suggest that such a polygenic influence, if there is any, is not large, and highlight the importance of conducting further, larger scale studies to obtain more information on the genetic architecture of this clinically relevant phenotype.
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| 3. |
- Kern, Ralph, et al.
(author)
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Coulomb Excitation of Proton-rich N = 80 Isotones at HIE-ISOLDE
- 2020
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In: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 1555:1
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Journal article (peer-reviewed)abstract
- A projectile Coulomb-excitation experiment was performed at the radioactive ion beam facility HIE-ISOLDE at CERN. The radioactive 140Nd and 142Sm ions were post accelerated to the energy of 4.62 MeV/A and impinged on a 1.45 mg/cm2-thin 208Pb target. The γ rays depopulating the Coulomb-excited states were recorded by the HPGe-array MINIBALL. The scattered charged particles were detected by a double-sided silicon strip detector in forward direction. Experimental γ-ray intensities were used for the determination of electromagnetic transition matrix elements. Preliminary results for the reduced transition strength of the B(M1 23+ to 21+)=0.35(19) μN2 of 140Nd and a first estimation for 142Sm have been deduced using the Coulomb-excitation calculation software GOSIA. The 23+ states of 140Nd and 142Sm show indications of being the main fragment of the proton-neutron mixed-symmetry 21, ms+ state.
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| 4. |
- Kern, Ralph, et al.
(author)
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Search for Isovector Valence-Shell Excitations in 140Nd and 142Sm via Coulomb excitation reactions of radioactive ion beams
- 2018
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In: International Conference on Nuclear Structure and Related Topics (NSRT18). - : EDP Sciences. - 2101-6275. ; 194
-
Conference paper (peer-reviewed)abstract
- Projectile Coulomb excitation experiments were performed at HIE-ISOLDE at CERN with the radioactive ion beams of 140Nd and 142Sm. Ions with an energy of 4:62 MeV/A were impinging on a 1.45 mg/cm2 thick 208Pb target. The γ-rays depopulating the Coulomb-excited states were recorded by the HPGe-array MINIBALL and scattered particles were detected by a double-sided silicon strip detector. Experimental intensities were used for the determination of electromagnetic transition matrix elements. A preliminary result of the B(M1; 2+ 3 → 2+ 1) of 140Nd and an upper limit for the case of 142Sm are revealing the main fragments of the proton-neutron mixed-symmetry 2+ 1;ms states.
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| 5. |
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| 6. |
- Leefman, Tim, et al.
(author)
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An Imaging Mass Spectrometry Study on the Formation of Conditioning Films and Biofilms in the Subsurface (Äspö Hard Rock Laboratory, SE Sweden)
- 2015
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In: Geomicrobiology Journal. - : Informa UK Limited. - 0149-0451 .- 1521-0529. ; 32:3-4, s. 197-206
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Journal article (peer-reviewed)abstract
- Conditioning films and biofilms forming on surfaces of solid materials exposed to aqueous media play a key role in in the interaction between the geo- and biospheres. In this study, time-of-flight secondary ion mass spectrometry and scanning electron microscopy were used to investigate the time scale, mode of formation, and chemistry of conditioning films and biofilms that formed on Si substrates exposed to aquifer water in the subsurface Äspö Hard Rock Laboratory, SE-Sweden. The detection of fragment ions of amino acids, carbohydrates, and carboxylic acids revealed that different types of organic compounds had adhered to the Si surface already after 10 min of exposure to the aquifer fluids, whereas the attachment of microbial cells was first observed after 1000 min. The organic compounds first formed isolated μm-sized accumulations and subsequently started to distribute on the wafer surface more homogenously. Simultaneously further microorganisms attached to the surface and formed biofilm-like cell accumulations after 3 months of exposure to aquifer water.
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| 7. |
- Leefmann, Tim, et al.
(author)
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Biomarker imaging of single diatom cells in a microbial mat using time-of-flight secondary ion mass spectrometry (ToF-SIMS)
- 2013
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In: Organic Geochemistry. - : Elsevier BV. - 0146-6380 .- 1873-5290. ; 57, s. 23-33
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Journal article (peer-reviewed)abstract
- Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a surface sensitive MS technique that offers a new way of studying lipid biomarkers at the microscopic level, without the need to destroy the physical integrity of the sample by extraction. We applied ToF-SIMS to a cryosection of a microbial mat and compared the results with ToF-SIMS and gas chromatography-MS (GC-MS) analysis of extracts from the same material. A wide range of lipid biomarkers was identified with ToF-SIMS in the microbial mat cryosection. Spectra and ion images revealed that individual biomarkers, including fatty acids, mono-, di- and triacylglycerols, carotenoids and chlorophyll were localized with diatom cells identified as Planothidium lanceolatum using optical microscopy. This diatom species can thus be regarded as a major lipid source within the microbial mat system. The results underpin the idea that ToF-SIMS has the potential to become an important technique for future biomarker studies, in particular for the clear cut assignment of biomarkers to distinctive morphological structures and specific microorganisms within complex biogeochemical samples.
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| 8. |
- Leefmann, Tim, et al.
(author)
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Spectral characterization of ten cyclic lipids using time-of-flight secondary ion mass spectrometry
- 2013
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In: Rapid Communications in Mass Spectrometry. - : Wiley. - 0951-4198 .- 1097-0231. ; 27:5, s. 565-581
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Journal article (peer-reviewed)abstract
- RATIONALE Over the last decade, the high lateral resolution and imaging capabilities of time-of-flight secondary ion mass spectrometry (ToF-SIMS) have increasingly stimulated interest in studying organic molecules in complex environmental materials. However, unlike with the established mass spectrometric techniques, the use of ToF-SIMS in the biogeosciences is still hampered by a lack of reference spectra of the relevant biomarker compounds. Here we present and interpret ToF-SIMS reference spectra of ten different cyclic lipids that are frequently used as biological tracers in ecological, organic geochemical and geobiological studies. METHODS Standard compounds of α,β,β-(20R, 24S)-24-methylcholestane, (22E)-ergosta-5,7,22-trien-3β-ol, 17α(H),21β-(H)-30-norhopane, hope-17(21)-ene, hop-22(29)-ene, 17β(H),21β(H)-bacteriohopane-32,33,34,35-tetrol, 17β(H), 21β(H)-35-aminobacteriohopane-32,33,34-triol, α-tocopherol, β,β-carotene, chlorophyll a, and cryosections of microbial mats and a fungus were analyzed using a ToF-SIMS instrument equipped with a Bi 3+ cluster ion source. RESULTS The spectra obtained from the standard compounds showed peaks in the molecular weight range (molecular ions, protonated and deprotonated molecules, adduct ions) and diagnostic fragment ion peaks in both, positive and negative ion modes. For the cyclic hydrocarbons, however, the positive ion mode spectra typically showed more and stronger characteristic peaks than the negative ion mode spectra. Using real world samples the capability of ToF-SIMS to detect and image selected compounds in complex organic matrices was tested. 17β(H),21β(H)-35- Aminobacteriohopane-32,33,34-triol, carotene and chlorophyll a were successfully identified in cryosections of microbial mats, and the distribution of ergosterol was mapped at μm resolution in a cryosection of a fungus (Tuber uncinatum). CONCLUSIONS This study further highlights the utility of ToF-SIMS for the identification and localization of lipids within environmental samples and as a technique for biomarker-related research in organic geochemistry and geobiology.
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| 9. |
- Liebenau, Katharina, et al.
(author)
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A quantitative study on the degradation of whale bone lipids: implications for the preservation of fatty acids in marine sediments
- 2015
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In: Organic Geochemistry. - : Elsevier BV. - 0146-6380 .- 1873-5290. ; 89-90, s. 23-30
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Journal article (peer-reviewed)abstract
- The degradation and preservation affecting the biomarker record of ancient metazoa are not fully 33understood. We report on a five month experiment on the fate of fatty acids (FAs) during the degradation 34of recent whale vertebrae (Phocoena phocoena). Whale bones were analysed for extractable FAs and 35macromolecularly bound n-acyl compounds. Fresh bone showed extractable FAs dominated by 3616:1x7c, 16:0, 18:1x9c and 18:0. Calculated degradation rate constant (k) values showed a rapid 37decrease in FA concentration, with k values higher for unsaturated than for saturated compounds 38(e.g. 0.08/day for 18:1x9c, 0.05/day for 16:0). The appearance or increased abundance of distinctive 39methyl branched (e.g. i/ai-15:0 and -17:0, 10Me-16:0) and hydroxy FAs (e.g. 10OH-16:0 and 10OH- 4018:0) were observed, providing clear evidence for the microbial degradation of bone organic matter 41and an input of lipids from specialised bacteria. Catalytic hydropyrolysis (HyPy) of demineralised extrac- 42tion residues released up to 0.13% of the total n-C16 and n-C18 moieties in the degraded bones. This 43revealed that only a small, yet sizeable portion of bone-derived fatty acyl units was sequestered into 44(proto)kerogen during the earliest stages of degradation.
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| 10. |
- Lindgren, Johan, et al.
(author)
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Molecular preservation of the pigment melanin in fossil melanosomes.
- 2012
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In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 3:Online 08 May 2012
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Journal article (peer-reviewed)abstract
- Fossil feathers, hairs and eyes are regularly preserved as carbonized traces comprised of masses of micrometre-sized bodies that are spherical, oblate or elongate in shape. For a long time, these minute structures were regarded as the remains of biofilms of keratinophilic bacteria, but recently they have been reinterpreted as melanosomes; that is, colour-bearing organelles. Resolving this fundamental difference in interpretation is crucial: if endogenous then the fossil microbodies would represent a significant advancement in the fields of palaeontology and evolutionary biology given, for example, the possibility to reconstruct integumentary colours and plumage colour patterns. It has previously been shown that certain trace elements occur in fossils as organometallic compounds, and hence may be used as biomarkers for melanin pigments. Here we expand this knowledge by demonstrating the presence of molecularly preserved melanin in intimate association with melanosome-like microbodies isolated from an argentinoid fish eye from the early Eocene of Denmark.
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| 11. |
- Mhlekude, Baxolele, et al.
(author)
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Pharmacological inhibition of bromodomain and extra-terminal proteins induces an NRF-2-mediated antiviral state that is subverted by SARS-CoV-2 infection
- 2023
-
In: PLoS Pathogens. - : Public Library of Science (PLoS). - 1553-7366 .- 1553-7374. ; 19:9
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Journal article (peer-reviewed)abstract
- Inhibitors of bromodomain and extra-terminal proteins (iBETs), including JQ-1, have been suggested as potential prophylactics against SARS-CoV-2 infection. However, molecular mechanisms underlying JQ-1-mediated antiviral activity and its susceptibility to viral subversion remain incompletely understood. Pretreatment of cells with iBETs inhibited infection by SARS-CoV-2 variants and SARS-CoV, but not MERS-CoV. The antiviral activity manifested itself by reduced reporter expression of recombinant viruses, and reduced viral RNA quantities and infectious titers in the culture supernatant. While we confirmed JQ-1-mediated downregulation of expression of angiotensin-converting enzyme 2 (ACE2) and interferon-stimulated genes (ISGs), multi-omics analysis addressing the chromatin accessibility, transcriptome and proteome uncovered induction of an antiviral nuclear factor erythroid 2-related factor 2 (NRF-2)-mediated cytoprotective response as an additional mechanism through which JQ-1 inhibits SARS-CoV-2 replication. Pharmacological inhibition of NRF-2, and knockdown of NRF-2 and its target genes reduced JQ-1-mediated inhibition of SARS-CoV-2 replication. Serial passaging of SARS-CoV-2 in the presence of JQ-1 resulted in predominance of ORF6-deficient variant, which exhibited resistance to JQ-1 and increased sensitivity to exogenously administered type I interferon (IFN-I), suggesting a minimised need for SARS-CoV-2 ORF6-mediated repression of IFN signalling in the presence of JQ-1. Importantly, JQ-1 exhibited a transient antiviral activity when administered prophylactically in human airway bronchial epithelial cells (hBAECs), which was gradually subverted by SARS-CoV-2, and no antiviral activity when administered therapeutically following an established infection. We propose that JQ-1 exerts pleiotropic effects that collectively induce an antiviral state in the host, which is ultimately nullified by SARS-CoV-2 infection, raising questions about the clinical suitability of the iBETs in the context of COVID-19.
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| 12. |
- Schiele, Miriam A., et al.
(author)
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Therapygenetic effects of 5-HTTLPR on cognitive-behavioral therapy in anxiety disorders : A meta-analysis
- 2021
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In: European Neuropsychopharmacology. - : Elsevier. - 0924-977X .- 1873-7862. ; 44, s. 105-120
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Journal article (peer-reviewed)abstract
- There is a recurring debate on the role of the serotonin transporter gene linked polymorphic region (5-HTTLPR) in the moderation of response to cognitive behavioral therapy (CBT) in anxiety disorders. Results, however, are still inconclusive. We here aim to perform a meta-analysis on the role of 5-HTTLPR in the moderation of CBT outcome in anxiety disorders. We investigated both categorical (symptom reduction of at least 50%) and dimensional outcomes from baseline to post-treatment and follow-up. Original data were obtained from ten independent samples (including three unpublished samples) with a total of 2,195 patients with primary anxiety disorder. No significant effects of 5-HTTLPR genotype on categorical or dimensional outcomes at post and follow-up were detected. We conclude that current evidence does not support the hypothesis of 5-HTTLPR as a moderator of treatment outcome for CBT in anxiety disorders. Future research should address whether other factors such as long-term changes or epigenetic processes may explain further variance in these complex gene-environment interactions and molecular-genetic pathways that may confer behavioral change following psychotherapy.
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| 13. |
- Siljeström, Sandra, 1980-, et al.
(author)
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Analysis of hopanes and steranes in single oil-bearing fluid inclusions using time-of-flight secondary ion mass spectrometry (ToF-SIMS)
- 2010
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In: Geobiology. - : Wiley. - 1472-4677 .- 1472-4669. ; 8:1, s. 37-44
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Journal article (peer-reviewed)abstract
- Steranes and hopanes are organic biomarkers used as indicators for the first appearance of eukaryotes and cyanobacteria on Earth. Oil-bearing fluid inclusions may provide a contamination-free source of Precambrian biomarkers, as the oil has been secluded from the environment since the formation of the inclusion. However, analysis of biomarkers in single oil-bearing fluid inclusions, which is often necessary due to the presence of different generations of inclusions, has not been possible due to the small size of most inclusions. Here, we have used time-of-flight secondary ion mass spectrometry (ToF-SIMS) to monitor in real time the opening of individualinclusions trapped in hydrothermal veins of fluorite and calcite and containing oil from Ordovician source rocks. Opening of the inclusions was performed by using a focused C60+ ion beam and the in situ content was preciselyanalysed for C27–C29 steranes and C29–C32 hopanes using Bi3+ as primary ions. The capacity to unambiguouslydetect these biomarkers in the picoliter amount of crude oil from a single, normal-sized (15–30 µm in diameter)inclusion makes the approach promising in the search of organic biomarkers for life’s early evolution on Earth.
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| 14. |
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| 15. |
- Siljeström, Sandra, et al.
(author)
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Detection of hopanes and steranes in single oil-bearing fluid inclusions using ToF-SIMS
- 2009
-
In: IMOG 24th International Meeting of Organic Geochemistry, Book of Abstract, www.imog2009.org. ; , s. 6-
-
Conference paper (other academic/artistic)abstract
- Hopanes and steranes are key biomarkers when tracking early evolution of life on Earth. A potential contamination-free source of Precambrian biomarkers is oil-bearing fluid inclusions as the oil has been secluded from the environment since the formation of the inclusion. Due to presence of often several generations of inclusions it can be problematic to assign the biomarkers to specific inclusions. It has, however, because of the small size of inclusions (5-30 µm), not been possible to analyse single oil-bearing fluid inclusions. We present here an approach employing time-of-flight secondary ion mass spectrometry (ToF-SIMS) to selectively open individual oil inclusions in situ by ion etching, and precisely analyse their picoliter content for steranes and hopanes. A number of oil-bearing inclusions from hydrothermal veins in the Siljan impact structure in south-central Sweden were analysed. The approach used for analysis of a single inclusion consisted of the following steps i) localization of suitable inclusion in double polished thin section with optical microscopy, ii) opening of inclusion by ion etching with C60+ gun inside the ToF-SIMS instrument while recording in real-time the opening of the inclusion and, iii) analysis of the exposed inclusion contents with ToF-SIMS. The micrographs and the ToF-SIMS ion images collected before, during and after analysis ensured the correct inclusion had been analysed. ToF-SIMS spectra reconstructed from analysis times and 2D regions of interest with increased organic ion signal showed a large number of organic peaks (up to m/z 500) that are characteristic for a crude oil. Comparison of the reconstructed spectra with those of a Siljan seep oil, which has previously been analysed with ToF-SIMS, showed a high degree of resemblance, as expected from the geological interpretation of the origin on the oils. All major characteristic peaks for several hopanes and steranes were detected in the mass spectra from the single fluid inclusion (Fig. 1). The agreement with respect to mass accuracy (< 50 ppm), fragment pattern and isotope distributions between these peaks and those observed in spectra from standard samples and from hopanes and steranes in the Siljan seep oil, provide strong evidence for the presence of hopanes and steranes in the analysed single fluid inclusions. The results thus demonstrate that the approach presented here has the capability to detect specific biomarkers in individual single oil inclusions. It is to our knowledge the first time hopanes and steranes have been detected in single oil-bearing fluid inclusins and the next step will be to analyse single oil-bearing fluid inclusions in Precambrian rocks with ToF-SIMS in search for organic biomarkers. Detection of hopanes and steranes in such an inclusion could help to answer questions regarding early evolution of life on Earth, including the first appearance of the eukaryotes on Earth.
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| 16. |
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| 17. |
- Siljeström, Sandra, et al.
(author)
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Detection of organic biomarkers in crude oils using ToF-SIMS
- 2009
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In: Organic Geochemistry. - : Elsevier BV. - 0146-6380 .- 1873-5290. ; 40:1, s. 135-143
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Journal article (peer-reviewed)abstract
- In this study, we show that time of flight-secondary ion mass spectrometry (ToF-SIMS) can be used todetect organic biomarkers, such as hopanes and steranes, in non-fractionated crude oils, without extractionand chemical preparation. Hopanes and steranes may provide valuable information on the history oflife on early Earth, particularly if they are present in fluid inclusions in ancient rocks. Due to the presenceof different generations of inclusions in even very small rock samples, it would be advantageous to find amethod capable of detecting biomarkers in single oil rich fluid inclusions. The capability of ToF-SIMS fordetailed chemical analysis of very small sample amounts makes it a potential technique for such analysis,and in this work this possibility is explored. The presence of hopanes and steranes in four different crudeoils of different ages and stages of biodegradation was investigated using ToF-SIMS and GC–MS. By combininganalyses of biomarker standards, crude oils and chromatographic oil fractions, specific peaks forthe different biomarkers were identified in the ToF-SIMS spectra. The presence of these peaks in the spectrafrom the crude oil samples could be attributed to the biomarkers based on exact mass determinationand by comparison with the spectra from the biomarker containing and biomarker lacking fractions,respectively. In addition, the results show that a significant biomarker signal may be obtained from a 10 µm2 oil sample, demonstrating the potential of ToF-SIMS for analysis of single oil bearing fluid inclusions,which in turn may contribute to a better understanding of the early history of life on Earth.
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| 18. |
- Siljeström, Sandra, 1980-, et al.
(author)
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ToF-SIMS analysis of hopanes and steranes in single oil-bearing fluid inclusions
- 2009
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In: Geochimica et Cosmochimica Acta, vol 73, A1223.
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Conference paper (other academic/artistic)abstract
- Hopanes and steranes are key biomarkers when tracking early evolution of life on Earth. A potential contamination-free source of such biomarkers is oil-bearing fluid inclusions as the oil has been secluded from the environment since the the inclusion was trapped. Using extraction-based techniques (GC/MS, LC/MS), it is, however, problematic to assign the extracted biomarkers to specific inclusions, due to the presence of often several generations of inclusions. As yet, it has not been possible to selectively analyse syngenetic inclusions for their biomarker content, because of their small size (5-30 µm in diameter). Here we present an approach employing time-of-flight secondary ion mass spectrometry (ToF-SIMS) to open and directly analyse the picoliter content of individual oil inclusions in petrographic thin sections of the target rocks. A number of oil-bearing inclusions (20-30 µm in diameter) from hydrothermal veins in the Siljan impact structure, Sweden, were analysed. The approach consisted of the following steps; i) localization of a suitable inclusion in a thin section using optical microscopy, ii) opening of the inclusion by ion etching with a C60+ sputter gun inside the ToF-SIMS instrument while recording in real-time the opening of the inclusion and, iii) analysis of the exposed inclusion contents with ToF-SIMS. ToF-SIMS spectra from the analysed inclusions showed a large number of organic peaks that are characteristic for crude oils, including all major diagnostic peaks for several hopanes and steranes. To our knowledge, it is the first time hopanes and steranes have been detected in single oil-bearing fluid inclusions. We are currently using this approach for analysing single inclusions in Precambrian rocks, in search of organic biomarkers that could help to answer questions regarding early evolution of life on Earth.
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| 19. |
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| 20. |
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| 21. |
- Siljeström, Sandra, et al.
(author)
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ToF-SIMS Possibilities in Geobiology
- 2008
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In: Astrobiology. - : Mary Ann Liebert Inc. - 1531-1074 .- 1557-8070. ; , s. 329-
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Conference paper (other academic/artistic)abstract
- Signs of earliest life on Earth are often controversial. Organic biomarkers, which are widely used to identify biological traces in geological samples, can provide additional information. We present examples of how Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) can be used on its own and in combination with other techniques to detect biomarkers in a variety of samples, including crude oils and microbial cells. ToF-SIMS with its unique combination of absolute sensitivity, high mass resolution and imaging capabilities can help answer geobiological questions and may ultimately be applied to Early Earth and extraterrestrial samples.
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| 22. |
- Sjövall, Peter, et al.
(author)
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Detection of organic biomarkers in crude oils using ToF-SIMS
- 2009
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In: Organic Geochemistry. ; 40, s. 135-143
-
Journal article (peer-reviewed)abstract
- In this study, we show that time of flight-secondary ion mass spectrometry (ToF-SIMS) can be used to detect organic biomarkers, such as hopanes and steranes, in non-fractionated crude oils, without extraction and chemical preparation. Hopanes and steranes may provide valuable information on the history of life on early Earth, particularly if they are present in fluid inclusions in ancient rocks. Due to the presence of different generations of inclusions in even very small rock samples, it would be advantageous to find a method capable of detecting biomarkers in single oil rich fluid inclusions. The capability of ToF-SIMS for detailed chemical analysis of very small sample amounts makes it a potential technique for such analysis, and in this work this possibility is explored.
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| 23. |
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| 24. |
- Sjövall, Peter, et al.
(author)
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Organic Geochemical Microanalysis by Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS)
- 2008
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In: Geostandards and Geoanalytical Research. ; 32, s. 267-277
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Journal article (peer-reviewed)abstract
- Time-of-flight secondary ion mass spectrometry(ToF-SIMS) is a powerful method for the chemicalanalysis of solid surfaces. In this paper, thecapabilities and limitations of this technique andthe potential for its use in geochemical research areoutlined. Using ToF-SIMS, the chemical compositionof sample structures down to 10–100 μm can bedetermined, without the need for pre-selection orlabelling of the analysed substances. In addition,the lateral distribution of organic and inorganiccompounds can be mapped in geochemicalsamples at a resolution in the micrometre range.The capabilities of the technique in geochemistryare illustrated by two examples. In the first example,it is shown that ToF-SIMS can be used to detectbiomarkers in oil samples, making it a promisingmethod for the analysis of biomarkers in fluidinclusions. In the second example, a number ofspecific lipid biomarkers were identified andmapped on the surface of a microbial matcryosection surface. Post-measurement opticalmicroscopy correlated the localisation of the lipidswith the presence of methanotrophic archaea in themicrobial mat.
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| 25. |
- Sjövall, Peter, et al.
(author)
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Using ToF-SIMS to study biomarkers
- 2011
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In: Annual Review of Earth and Planetary Science. ; 39, s. 125-156
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Journal article (peer-reviewed)
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| 26. |
- Thiel, Volker, et al.
(author)
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Occurrence and fate of fatty acyl biomarkers in an ancient whale bone (Oligocene, El Cien Formation, Mexico)
- 2014
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In: Organic Geochemistry. - : Elsevier BV. - 0146-6380 .- 1873-5290. ; 68:Mar, s. 71-81
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Journal article (peer-reviewed)abstract
- The taphonomic and diagenetic processes by which organic substances are preserved in animal remains are not completely known and the originality of putative metazoan biomolecules in fossil samples is a matter of scientific discussion. Here we report on biomarker information preserved in a fossil whale bone from an Oligocene phosphatic limestone (El Cien Fm., Mexico), with a focus on fatty acyl compounds. Extracts were quantitatively analysed using gas chromatography-mass spectrometry (GC-MS) and, to identify macromolecular-linked remains, demineralised extraction residues were subjected to catalytic hydropyrolysis (HyPy). To better recognise potential authentic (i.e. animal-derived) lipids, the data from the ancient bone were compared with those obtained from (i) the adjacent host sediment of the fossil and (ii) a recent whale (Phocoena phocoena) vertebra. In addition, the spatial distribution of organic and inorganic species was observed at the μm level by imaging MS (time-of-flight-secondary ion mass spectrometry, ToF-SIMS). Our results revealed a rather even distribution of hydrocarbon-, O- and N-containing ions in the trabecular network of the ancient bone. A different, more patchy arrangement of organic compounds was evident in the former marrow cavities that were partly cemented by clotted micrites of putative microbial origin. The concentration of fatty acids (FAs) in the ancient bone was in the permil range of the amount extracted from the recent whale vertebra. Endogenous compounds, including monoenoic n-C16and n-C18 as well as branched FAs, were identified in the fossil bone by comparison with the host sediment. Ca. 80% of the prevalent n-C16 and n-C18 moieties in the ancient bone were extractable as FAs, whereas ca. 20% were covalently bound in the non-saponifiable kerogen fraction. Ample pyrite precipitates, distinctive 10-methyl branched FAs and microbial microborings ("tunneling") indicate that sulfate reducers and collagen-degrading actinomycetes were central players in the microbial decomposition of the bone. Similarities with reported microbial FA patterns suggest that the FAs in the fossil bone were largely contributed by these microbial "last eaters". The results highlight some of the degradation and preservation mechanisms during marine FA diagenesis in the "natural laboratory" of bones, and therefore the processes that lead to either degradation, preservation, or introduction of these widespread biomolecules in the fossils of ancientmarine animals.
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| 27. |
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| 28. |
- Weimann, Lena, et al.
(author)
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Insights Into Carbonaceous Matter in ∼3.5 Ga Hydrothermal Barites from the Dresser Formation (Pilbara Craton, Australia)
- 2023
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In: IMOG 2023.
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Conference paper (peer-reviewed)abstract
- The emergence of life on the juvenile Earth is still poorly understood and remains one of the major questions in geobiological research. Some of our planet´s most ancient rocks contain carbonaceous matter (CM) that may represent a valuable archive to trace earliest life.However, it is often difficult to prove the origin and syngeneity of such CM. Here we report on CM preserved in ∼3.5 Ga old barites from the Dresser Formation (Pilbara Carton, Western Australia). On outcrop scale, spatial associations between bedded and vein-hosted barites suggest that the bedded barite may have formed from hydrothermal fluids discharging into subaquatic caldera environments [1]. Bedded barites associated with stromatolites contain abundant CM (total organic carbon = 0.3 wt% [2]) whose nature has been investigated further. Three populations of CM were recognized by means of light microscopy and high-resolution Raman mapping: (i) CM flakes at the edges of single growth bands of barite crystals, (ii) CM dispersed within barite crystals, and (iii) CM in 50–300 µm wide secondary quartz veins that cross-cut barite crystals. Raman spectra of the CM indicate peak metamorphic temperatures of approximately 300 ± 50 °C, corresponding to lower greenschist-facies conditions which are consistent with the metamorphic overprint by granitic intrusions in the area ∼3.3 Ga ago [3]. Near edge X-ray absorption fine structure (NEXAFS) and solid-state nuclear magnetic resonance (NMR) measurements revealed a highly aromatic nature of the CM which is in line with relatively high thermal maturity. As all three CM populations experienced the major metamorphic overprint ∼3.3 Ga ago, a syngenetic formation of the CM with the host barite can be assumed or, in case of the vein-hosted secondary CM, an emplacement soon after barite growth.
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