TY - THES A1 - van der Veen, Iris T1 - Defining moisture sources and (palaeo)environmental conditions using isotope geochemistry in the NW Himalaya N2 - Anthropogenic climate change alters the hydrological cycle. While certain areas experience more intense precipitation events, others will experience droughts and increased evaporation, affecting water storage in long-term reservoirs, groundwater, snow, and glaciers. High elevation environments are especially vulnerable to climate change, which will impact the water supply for people living downstream. The Himalaya has been identified as a particularly vulnerable system, with nearly one billion people depending on the runoff in this system as their main water resource. As such, a more refined understanding of spatial and temporal changes in the water cycle in high altitude systems is essential to assess variations in water budgets under different climate change scenarios. However, not only anthropogenic influences have an impact on the hydrological cycle, but changes to the hydrological cycle can occur over geological timescales, which are connected to the interplay between orogenic uplift and climate change. However, their temporal evolution and causes are often difficult to constrain. Using proxies that reflect hydrological changes with an increase in elevation, we can unravel the history of orogenic uplift in mountain ranges and its effect on the climate. In this thesis, stable isotope ratios (expressed as δ2H and δ18O values) of meteoric waters and organic material are combined as tracers of atmospheric and hydrologic processes with remote sensing products to better understand water sources in the Himalayas. In addition, the record of modern climatological conditions based on the compound specific stable isotopes of leaf waxes (δ2Hwax) and brGDGTs (branched Glycerol dialkyl glycerol tetraethers) in modern soils in four Himalayan river catchments was assessed as proxies of the paleoclimate and (paleo-) elevation. Ultimately, hydrological variations over geological timescales were examined using δ13C and δ18O values of soil carbonates and bulk organic matter originating from sedimentological sections from the pre-Siwalik and Siwalik groups to track the response of vegetation and monsoon intensity and seasonality on a timescale of 20 Myr. I find that Rayleigh distillation, with an ISM moisture source, mainly controls the isotopic composition of surface waters in the studied Himalayan catchments. An increase in d-excess in the spring, verified by remote sensing data products, shows the significant impact of runoff from snow-covered and glaciated areas on the surface water isotopic values in the timeseries. In addition, I show that biomarker records such as brGDGTs and δ2Hwax have the potential to record (paleo-) elevation by yielding a significant correlation with the temperature and surface water δ2H values, respectively, as well as with elevation. Comparing the elevation inferred from both brGDGT and δ2Hwax, large differences were found in arid sections of the elevation transects due to an additional effect of evapotranspiration on δ2Hwax. A combined study of these proxies can improve paleoelevation estimates and provide recommendations based on the results found in this study. Ultimately, I infer that the expansion of C4 vegetation between 20 and 1 Myr was not solely dependent on atmospheric pCO2, but also on regional changes in aridity and seasonality from to the stable isotopic signature of the two sedimentary sections in the Himalaya (east and west). This thesis shows that the stable isotope chemistry of surface waters can be applied as a tool to monitor the changing Himalayan water budget under projected increasing temperatures. Minimizing the uncertainties associated with the paleo-elevation reconstructions were assessed by the combination of organic proxies (δ2Hwax and brGDGTs) in Himalayan soil. Stable isotope ratios in bulk soil and soil carbonates showed the evolution of vegetation influenced by the monsoon during the late Miocene, proving that these proxies can be used to record monsoon intensity, seasonality, and the response of vegetation. In conclusion, the use of organic proxies and stable isotope chemistry in the Himalayas has proven to successfully record changes in climate with increasing elevation. The combination of δ2Hwax and brGDGTs as a new proxy provides a more refined understanding of (paleo-)elevation and the influence of climate. N2 - Die Auswirkungen des menschgemachten Klimawandels wirken sich auch auf den Wasserkreislauf aus. Während manche Regionen höhere Niederschlagsmengen zu erwarten haben, werden andere mit stärkeren und häufigeren Trockenperioden zu konfrontiert sein. Diese Veränderungen haben einen unmittelbaren Einfluss auf Evaporation, Langzeit-Wasserreservoire, Grundwasserbildung, Schneefall und Gletscher. Da Gebirge und Hochplateaus überdurchschnittlich von den Auswirkungen des Klimawandels betroffen sind, ist die Wasserversorgung der Menschen entlang der dort entspringenden Flüsse gefährdet. Insbesondere der Himalaya gilt als instabile Region, dessen Abflüsse die Wasserversorgung von annähernd einer Milliarde Menschen gewährleisten. Um zu erwartende Veränderungen des Wasserbudgets in Abhängigkeit von verschiedenen möglichen Klimawandelszenarien abschätzen zu können, ist ein detaillierteres Verständnis des Wasserkreislaufs in Hochgebirgen und -plateaus erforderlich. Neben dem globalen Klimawandel gibt es weitere Faktoren, die sich auf den Wasserkreislauf auswirken. Das Wechselspiel zwischen Gebirgsbildung und klimatischen Bedingungen beeinflusst den Wasserkreislauf auf geologischen Zeitskalen. Entsprechende Veränderungen und ihre Auswirkungen lassen sich jedoch nur eingeschränkt bestimmen. Mittels geeigneter Proxies für höhenbedingte Änderungen der Hydrologie lassen sich der Orogeneseverlauf sowie dessen klimatische Auswirkungen allerdings genauer rekonstruieren. In der vorliegenden Arbeit werden die Verhältnisse stabiler Isotope (als δ2H und δ18O ausgedrückt) von meteorischen Wassern sowie von organischem Material mit Methoden der Satellitenfernerkundung als Indikator für atmosphärische und hydrologische Prozesse kombiniert, um ein besseres Verständnis der verschiedenen Wasserquellen des Himalaya zu erlangen. Darüber hinaus wurde der Link zwischen modernen klimatischen Bedingungen und verbindungsspezifischen stabilen Isotopen von Blattwachsen (δ2Hwax) sowie von brGDGTs (branched Glycerol dialkyl glycerol tetraethers) rezenter Bodenproben aus den Einzugsgebieten vierer Flüsse des Himalaya hergestellt, um sie als Paläo-Klima- und Paläo-Höhenproxy verwenden zu können. Zu guter Letzt wurden hydrologische Veränderungen auf einer Zeitskala von 20 Mio. Jahren anhand von δ13C- and δ18O-Werten von Bodencarbonat und organischem Material aus Sedimentschnitten der pre-Siwalik und Siwalik-Einheiten nachvollzogen. Die Erkenntnisse dieser tragen zu einer deutlich genaueren Rekonstruktion von Vegetationsänderungen und der Entwicklung der Monsun-Intensität sowie -Saisonalität bei. Die Isotopenzusammensetzung der Oberflächenwasser der untersuchten Flüsse wird hauptsächlich durch Rayleigh-Destillation der im Wesentlichen vom Indischen Sommer Monsun eingetragenen Feuchtigkeit bestimmt. Der durch Satellitenfernerkundungsdaten bestätigte Anstieg des Deuterium-Exzesses (d-excess) im Frühjahr verdeutlicht den signifikanten Einfluss von Schnee- und Gletscherschmelze, der auch in Zeitreihen von Oberflächenwasserproben erkennbar ist. Sowohl brGDGT als auch δ2Hwax können potentiell die absolute Höhe zum Zeitpunkt ihrer Synthese abbilden, da sie stark mit der Lufttemperatur, bzw. mit Oberflächenwasser δ2H und somit indirekt auch mit der Höhe korreliert sind. Im direkten Vergleich der mittels brGDGT und δ2Hwax rekonstruierten Höhen ergaben sich insbesondere in ariden Teilen der Höhenprofile große Unterschiede. Diese sind hauptsächlich auf verstärkte Evapotranspiration und deren Auswirkung auf Pflanzenwasser und -wachse zurückzuführen. Basierend auf den Erkenntnissen der vorliegenden Arbeit können weitere vergleichende Untersuchungen beider Proxies genauere Paläo-Höhenstudien ermöglichen. Diese Arbeit zeigt, dass die Isotopie von Oberflächenwassern genutzt werden kann, um den sich ändernden Wasserhaushalt des Himalya im Kontext voraussichtlich weiter ansteigender Temperaturen zu beobachten. Unsicherheiten bei der Rekonstruktion von Paläo-Höhen konnten durch eine vergleichende Analyse zweier organischer Proxies (δ2Hwax and brGDGTs) aus Paläo-Bodenproben des Himalayas minimiert werden. Verhältnisse stabiler Isotope von Blattwachsen aus diesen Bodenproben spiegeln die Entwicklung der Vegetation unter dem Einfluss des Monsuns im späten Miozän wider. Zusammenfassend wurde erfolgreich gezeigt, dass organische Proxies und stabile Isotope höhenabhängige Änderungen des Klimas im Himalaya aufzeichnen können. Die Kombination von δ2Hwax and brGDGTs als neuer Proxy ermöglicht eine deutlich differenziertere Betrachtung von rekonstruierten Paläo-Höhen sowie Paläo-Klima. KW - stable isotope KW - Himalaya KW - n-alkanes KW - d-excess KW - biomarker KW - paleohydrology KW - GDGT KW - GDGT KW - Himalaya KW - Biomarker KW - Deuterium Exzesses KW - n-alkane KW - Paläohydrologie KW - stabilen Isotopen Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-514397 ER - TY - THES A1 - Stößel, Daniel T1 - Biomarker Discovery in Multiple Sclerosis and Parkinson’s disease T1 - Biomarkerentwicklung in Multiple Sklerose und der Parkinson-Krankheit BT - novel insights into metabolic disease mechanisms N2 - Neuroinflammatory and neurodegenerative diseases such as Parkinson's (PD) and multiple sclerosis (MS) often result in a severe impairment of the patient´s quality of life. Effective therapies for the treatment are currently not available, which results in a high socio-economic burden. Due to the heterogeneity of the disease subtypes, stratification is particularly difficult in the early phase of the disease and is mainly based on clinical parameters such as neurophysiological tests and central nervous imaging. Due to good accessibility and stability, blood and cerebrospinal fluid metabolite markers could serve as surrogates for neurodegenerative processes. This can lead to an improved mechanistic understanding of these diseases and further be used as "treatment response" biomarkers in preclinical and clinical development programs. Therefore, plasma and CSF metabolite profiles will be identified that allow differentiation of PD from healthy controls, association of PD with dementia (PDD) and differentiation of PD subtypes such as akinetic rigid and tremor dominant PD patients. In addition, plasma metabolites for the diagnosis of primary progressive MS (PPMS) should be investigated and tested for their specificity to relapsing-remitting MS (RRMS) and their development during PPMS progression. By applying untargeted high-resolution metabolomics of PD patient samples and in using random forest and partial least square machine learning algorithms, this study identified 20 plasma metabolites and 14 CSF metabolite biomarkers. These differentiate against healthy individuals with an AUC of 0.8 and 0.9 in PD, respectively. We also identify ten PDD specific serum metabolites, which differentiate against healthy individuals and PD patients without dementia with an AUC of 1.0, respectively. Furthermore, 23 akinetic-rigid specific plasma markers were identified, which differentiate against tremor-dominant PD patients with an AUC of 0.94 and against healthy individuals with an AUC of 0.98. These findings also suggest more severe disease pathology in the akinetic-rigid PD than in tremor dominant PD. In the analysis of MS patient samples a partial least square analysis yielded predictive models for the classification of PPMS and resulted in 20 PPMS specific metabolites. In another MS study unknown changes in human metabolism were identified after administration of the multiple sclerosis drug dimethylfumarate, which is used for the treatment of RRMS. These results allow to describe and understand the hitherto completely unknown mechanism of action of this new drug and to use these findings for the further development of new drugs and targets against RRMS. In conclusion, these results have the potential for improved diagnosis of these diseases and improvement of mechanistic understandings, as multiple deregulated pathways were identified. Moreover, novel Dimethylfumarate targets can be used to aid drug development and treatment efficiency. Overall, metabolite profiling in combination with machine learning identified as a promising approach for biomarker discovery and mode of action elucidation. N2 - Neuroinflammatorische and neurodegenerative Erkrankungen wie Parkinson (PD) und Multiple Sklerose (MS) gehen oft mit einer starken Beeinträchtigung der Lebensqualität einher. Effektive Therapien für die Behandlung sind derzeit nicht verfügbar, was nicht zuletzt eine hohe sozioökonomische Last zur Folge hat. Aufgrund der Heterogenität der Krankheitsbilder ist eine Stratifizierung gerade in der Frühphase der Erkrankung schwierig und basiert hauptsächlich auf klinischen Parametern wie bspw. neurophysiologischen Tests und bildgebenden Verfahren. Aufgrund ihrer guten Zugänglichkeit und Stabilität könnten bestimmte Blut- und Liquor-Metabolitenmarker als Surrogat für neurodegenerative Prozesse dienen, zu einem verbesserten mechanistischen Verständnis dieser Krankheiten führen und nicht zuletzt als “treatment response“ Biomarker in präklinischen und klinischen Entwicklungsprogrammen herangezogen werden. In dieser Arbeit sollten deshalb Plasma- und CSF-Metabolitprofile identifiziert werden, die eine Differenzierung von PD zu gesunden Kontrollen, Assoziierung zu PD mit Demenz (PDD) sowie eine Abgrenzung zu unterschiedlichen PD-Subtypen wie akinetisch-rigiden sowie tremor-dominanten PD-Patienten ermöglichen. Weiterhin wurden in dieser Arbeit Plasmametabolite zur Diagnose von primär-progressiver MS (PPMS) erforscht und auf ihre Spezifität gegenüber schubförmig remittierender MS (RRMS) und PD geprüft sowie deren Verlauf während der PPMS Progression getestet. Hierbei konnten durch “untargeted Metabolomics“ in Kombination mit statistischen Modellen mehrere Plasma- und CSF-Metabolite in PD-Patienten/Erkrankten ermittelt werden, die mit Hilfe von statistischen Diagnosemodellen eine Differenzierung zu gesunden Personen ermöglichen. Darüber hinaus wurden in dieser Arbeit PDD-spezifische Serummetabolite identifiziert, die wiederum genutzt werden können, um diesen PD-Typen von gesunden Individuen und PD-Patienten ohne Demenz abzugrenzen. Des Weiteren konnten bei akinetisch-rigiden PD-Patienten spezifische Metabolite entdeckt werden, die im Vergleich zu tremor-dominanten PD-Patienten eine stärkere metabolische Krankheitssymptomatik suggerieren. Im Zusammenhang mit PPMS wurden in dieser Arbeit spezifische Plasma-Metabolite entdeckt, die zur Diagnose gegen RRMS, PD und gesunden Kontrollen genutzt werden können. Interessanterweise zeigte dabei ein spezifisches Lipid geringere Werte im PPMS Krankheitsverlauf, wodurch sich dieses als möglicher Marker zur Progressionsdiagnostik dieser Krankheit qualifiziert. Abschließend konnten in dieser Arbeit im humanen Stoffwechsel bisher unbekannte Angriffspunkte des Medikaments Dimethylfumarat, das zur Behandlung von RRMS verwendet wird, ermittelt werden. Durch diese Ergebnisse kann der bis jetzt gänzlich unbekannte Wirkungsmechanismus dieses neuen Medikaments besser beschrieben und verstanden, sowie zur Weiterentwicklung neuer Medikamente gegen RRMS genutzt werden. KW - metabolomics KW - biomarker KW - multiple sclerosis KW - Parkinson's disease KW - neurodegeneration KW - neuroinflammation KW - machine-learning KW - Parkinson-Krankheit KW - Biomarker KW - Maschinelles-Lernen KW - Metabolomics KW - Multiple-Sklerose Y1 - 2018 ER - TY - GEN A1 - Stoessel, Daniel A1 - Stellmann, Jan-Patrick A1 - Willing, Anne A1 - Behrens, Birte A1 - Rosenkranz, Sina C. A1 - Hodecker, Sibylle C. A1 - Stürner, Klarissa H. A1 - Reinhardt, Stefanie A1 - Fleischer, Sabine A1 - Deuschle, Christian A1 - Maetzler, Walter A1 - Berg, Daniela A1 - Heesen, Christoph A1 - Walther, Dirk A1 - Schauer, Nicolas A1 - Friese, Manuel A. A1 - Pless, Ole T1 - Metabolomic profiles for primary progressive multiple sclerosis stratification and disease course monitoring T2 - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe N2 - Primary progressive multiple sclerosis (PPMS) shows a highly variable disease progression with poor prognosis and a characteristic accumulation of disabilities in patients. These hallmarks of PPMS make it difficult to diagnose and currently impossible to efficiently treat. This study aimed to identify plasma metabolite profiles that allow diagnosis of PPMS and its differentiation from the relapsing remitting subtype (RRMS), primary neurodegenerative disease (Parkinson’s disease, PD), and healthy controls (HCs) and that significantly change during the disease course and could serve as surrogate markers of multiple sclerosis (MS)-associated neurodegeneration over time. We applied untargeted high-resolution metabolomics to plasma samples to identify PPMS-specific signatures, validated our findings in independent sex- and age-matched PPMS and HC cohorts and built discriminatory models by partial least square discriminant analysis (PLS-DA). This signature was compared to sex- and age-matched RRMS patients, to patients with PD and HC. Finally, we investigated these metabolites in a longitudinal cohort of PPMS patients over a 24-month period. PLS-DA yielded predictive models for classification along with a set of 20 PPMS-specific informative metabolite markers. These metabolites suggest disease-specific alterations in glycerophospholipid and linoleic acid pathways. Notably, the glycerophospholipid LysoPC(20:0) significantly decreased during the observation period. These findings show potential for diagnosis and disease course monitoring, and might serve as biomarkers to assess treatment efficacy in future clinical trials for neuroprotective MS therapies. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 694 KW - untargeted metabolomics KW - biomarker KW - PPMS KW - MS neurodegeneration KW - LysoPC(20:0) Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-426307 SN - 1866-8372 IS - 694 ER - TY - JOUR A1 - Stoessel, Daniel A1 - Stellmann, Jan-Patrick A1 - Willing, Anne A1 - Behrens, Birte A1 - Rosenkranz, Sina C. A1 - Hodecker, Sibylle C. A1 - Stuerner, Klarissa H. A1 - Reinhardt, Stefanie A1 - Fleischer, Sabine A1 - Deuschle, Christian A1 - Maetzler, Walter A1 - Berg, Daniela A1 - Heesen, Christoph A1 - Walther, Dirk A1 - Schauer, Nicolas A1 - Friese, Manuel A. A1 - Pless, Ole T1 - Metabolomic Profiles for Primary Progressive Multiple Sclerosis Stratification and Disease Course Monitoring JF - Frontiers in human neuroscienc N2 - Primary progressive multiple sclerosis (PPMS) shows a highly variable disease progression with poor prognosis and a characteristic accumulation of disabilities in patients. These hallmarks of PPMS make it difficult to diagnose and currently impossible to efficiently treat. This study aimed to identify plasma metabolite profiles that allow diagnosis of PPMS and its differentiation from the relapsing remitting subtype (RRMS), primary neurodegenerative disease (Parkinson’s disease, PD), and healthy controls (HCs) and that significantly change during the disease course and could serve as surrogate markers of multiple sclerosis (MS)-associated neurodegeneration over time. We applied untargeted high-resolution metabolomics to plasma samples to identify PPMS-specific signatures, validated our findings in independent sex- and age-matched PPMS and HC cohorts and built discriminatory models by partial least square discriminant analysis (PLS-DA). This signature was compared to sex- and age-matched RRMS patients, to patients with PD and HC. Finally, we investigated these metabolites in a longitudinal cohort of PPMS patients over a 24-month period. PLS-DA yielded predictive models for classification along with a set of 20 PPMS-specific informative metabolite markers. These metabolites suggest disease-specific alterations in glycerophospholipid and linoleic acid pathways. Notably, the glycerophospholipid LysoPC(20:0) significantly decreased during the observation period. These findings show potential for diagnosis and disease course monitoring, and might serve as biomarkers to assess treatment efficacy in future clinical trials for neuroprotective MS therapies. KW - untargeted metabolomics KW - biomarker KW - PPMS KW - MS neurodegeneration KW - LysoPC(20:0) Y1 - 2018 U6 - https://doi.org/10.3389/fnhum.2018.00226 SN - 1662-5161 VL - 12 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Stoessel, Daniel A1 - Schulte, Claudia A1 - dos Santos, Marcia C. Teixeira A1 - Scheller, Dieter A1 - Rebollo-Mesa, Irene A1 - Deuschle, Christian A1 - Walther, Dirk A1 - Schauer, Nicolas A1 - Berg, Daniela A1 - da Costa, Andre Nogueira A1 - Maetzler, Walter T1 - Promising Metabolite Profiles in the Plasma and CSF of Early Clinical JF - Frontiers in Aging Neuroscience N2 - Parkinson's disease (PD) shows high heterogeneity with regard to the underlying molecular pathogenesis involving multiple pathways and mechanisms. Diagnosis is still challenging and rests entirely on clinical features. Thus, there is an urgent need for robust diagnostic biofluid markers. Untargeted metabolomics allows establishing low-molecular compound biomarkers in a wide range of complex diseases by the measurement of various molecular classes in biofluids such as blood plasma, serum, and cerebrospinal fluid (CSF). Here, we applied untargeted high-resolution mass spectrometry to determine plasma and CSF metabolite profiles. We semiquantitatively determined small-molecule levels (<= 1.5 kDa) in the plasma and CSF from early PD patients (disease duration 0-4 years; n = 80 and 40, respectively), and sex-and age-matched controls (n = 76 and 38, respectively). We performed statistical analyses utilizing partial least square and random forest analysis with a 70/30 training and testing split approach, leading to the identification of 20 promising plasma and 14 CSF metabolites. The semetabolites differentiated the test set with an AUC of 0.8 (plasma) and 0.9 (CSF). Characteristics of the metabolites indicate perturbations in the glycerophospholipid, sphingolipid, and amino acid metabolism in PD, which underscores the high power of metabolomic approaches. Further studies will enable to develop a potential metabolite-based biomarker panel specific for PD KW - biomarker KW - untargeted metabolomics KW - neurodegeneration KW - plasma KW - CSF KW - machinelearning Y1 - 2018 U6 - https://doi.org/10.3389/fnagi.2018.00051 SN - 1663-4365 VL - 10 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Shahid, Muhammad A1 - Manchi, G. A1 - Slunsky, Pavel A1 - Naseer, O. A1 - Fatima, A. A1 - Leo, B. A1 - Raila, Jens T1 - A systemic review of existing serological possibilities to diagnose canine osteoarthritis with a particular focus on extracellular matrix proteoglycans and protein JF - Polish journal of veterinary sciences : PJVS : the journal of Committee of Veterinary Sciences of Polish Academy of Sciences and University of Warmia and Mazury in Olsztyn N2 - Extra-cellular matrix (ECM) components are important and their stabilization is significant in maintaining normal healthy joint environment. In osteoarthritis (OA), ECM components are altered and indicate disease progression. The joint ECM is composed of proteoglycans (aggrecan, perlecan,inter α-trypsin inhibitor), glycoproteins (fibronectin, lubricin, COMP) and collagen types (most abundantly collagen type II) which represent structural and functional transformation during disease advancement. ECM investigation revealed significant biomarkers of OA that could be used as a diagnostic and therapeutic tool in different canine orthopedic diseases. This review deliberates our current findings of how the components of ECM change at the molecular level during disease progression in canine OA. KW - extra-cellular matrix KW - canine osteoarthritis KW - biomarker KW - synovial fluid KW - proteomix analysis Y1 - 2017 U6 - https://doi.org/10.1515/pjvs-2017-0024 SN - 1505-1773 SN - 2300-2557 VL - 20 IS - 1 SP - 189 EP - 201 PB - De Gruyter CY - Berlin ER - TY - JOUR A1 - Schulze-Makuch, Dirk A1 - Wagner, Dirk A1 - Kounaves, Samuel P. A1 - Mangelsdorf, Kai A1 - Devine, Kevin G. A1 - de Vera, Jean-Pierre A1 - Schmitt-Kopplin, Philippe A1 - Grossart, Hans-Peter A1 - Parro, Victor A1 - Kaupenjohann, Martin A1 - Galy, Albert A1 - Schneider, Beate A1 - Airo, Alessandro A1 - Froesler, Jan A1 - Davila, Alfonso F. A1 - Arens, Felix L. A1 - Caceres, Luis A1 - Cornejo, Francisco Solis A1 - Carrizo, Daniel A1 - Dartnell, Lewis A1 - DiRuggiero, Jocelyne A1 - Flury, Markus A1 - Ganzert, Lars A1 - Gessner, Mark O. A1 - Grathwohl, Peter A1 - Guan, Lisa A1 - Heinz, Jacob A1 - Hess, Matthias A1 - Keppler, Frank A1 - Maus, Deborah A1 - McKay, Christopher P. A1 - Meckenstock, Rainer U. A1 - Montgomery, Wren A1 - Oberlin, Elizabeth A. A1 - Probst, Alexander J. A1 - Saenz, Johan S. A1 - Sattler, Tobias A1 - Schirmack, Janosch A1 - Sephton, Mark A. A1 - Schloter, Michael A1 - Uhl, Jenny A1 - Valenzuela, Bernardita A1 - Vestergaard, Gisle A1 - Woermer, Lars A1 - Zamorano, Pedro T1 - Transitory microbial habitat in the hyperarid Atacama Desert JF - Proceedings of the National Academy of Sciences of the United States of America KW - habitat KW - aridity KW - microbial activity KW - biomarker KW - Mars Y1 - 2018 U6 - https://doi.org/10.1073/pnas.1714341115 SN - 0027-8424 VL - 115 IS - 11 SP - 2670 EP - 2675 PB - National Acad. of Sciences CY - Washington ER - TY - JOUR A1 - Schulze, Sven A1 - Wehrhold, Michel A1 - Hille, Carsten T1 - Femtosecond-Pulsed laser written and etched fiber bragg gratings for fiber-optical biosensing JF - Sensors N2 - We present the development of a label-free, highly sensitive fiber-optical biosensor for online detection and quantification of biomolecules. Here, the advantages of etched fiber Bragg gratings (eFBG) were used, since they induce a narrowband Bragg wavelength peak in the reflection operation mode. The gratings were fabricated point-by-point via a nonlinear absorption process of a highly focused femtosecond-pulsed laser, without the need of prior coating removal or specific fiber doping. The sensitivity of the Bragg wavelength peak to the surrounding refractive index (SRI), as needed for biochemical sensing, was realized by fiber cladding removal using hydrofluoric acid etching. For evaluation of biosensing capabilities, eFBG fibers were biofunctionalized with a single-stranded DNA aptamer specific for binding the C-reactive protein (CRP). Thus, the CRP-sensitive eFBG fiber-optical biosensor showed a very low limit of detection of 0.82 pg/L, with a dynamic range of CRP detection from approximately 0.8 pg/L to 1.2 mu g/L. The biosensor showed a high specificity to CRP even in the presence of interfering substances. These results suggest that the proposed biosensor is capable for quantification of CRP from trace amounts of clinical samples. In addition, the adaption of this eFBG fiber-optical biosensor for detection of other relevant analytes can be easily realized. KW - fiber Bragg gratings KW - ultra-fast laser inscription KW - fiber etching KW - nanostructure fabrication KW - fiber-optical sensors KW - aptamers KW - C-reactive protein KW - biomarker Y1 - 2018 U6 - https://doi.org/10.3390/s18092844 SN - 1424-8220 VL - 18 IS - 9 PB - MDPI CY - Basel ER - TY - THES A1 - Menges, Johanna T1 - Organic Carbon Storage, Transfer and Transformation in the Himalaya BT - insights from the Kali Gandaki Valley in Central Nepal N2 - The transfer of particulate organic carbon from continents to the ocean is an important component of the global carbon cycle. Transfer to and burial of photosynthetically fixed biospheric organic carbon in marine sediments can effectively sequester atmospheric carbon dioxide over geological timescales. The exhumation and erosion of fossil organic carbon contained in sedimentary rocks, i.e. petrogenic carbon, can result in remineralization, releasing carbon to the atmosphere. In contrast, eroded petrogenic organic carbon that gets transferred back to the ocean and reburied does not affect atmospheric carbon content. Mountain ranges play a key role in this transfer since they can source vast amounts of sediment including particulate organic carbon. Globally, the export of both, biospheric and petrogenic organic carbon has been linked to sediment export. Additionally, short transfer times from mountains to the ocean and high sediment concentrations have been shown to increase the likelihood of organic carbon burial. While the importance of mountain ranges in the organic carbon cycle is now widely recognized, the processes acting within mountain ranges to influence the storage, cycling and mobilization of organic carbon, as well as carbon fluxes from mountain ranges remain poorly constrained. In this thesis, I employ different methods to assess the nature and fate of particulate organic carbon in mountain belts, ranging from the molecular to regional landscape scale. These studies are located along the Trans-Himalayan Kali Gandaki River in Central Nepal. This river traverses all major geological and climatic zones of the Himalaya, from the dry northern Tibetan plateau to the high-relief, monsoon dominated steep High Himalaya and the lower relief and abundant vegetation of the Lesser Himalayan region. First, I document how biospheric organic matter has accumulated during the Holocene in the headwaters of the Kali Gandaki River valley, by combining compound specific isotope measurements with different dating methods and grain size data, and investigate the stability of this organic carbon reservoir on millennial timescales. I show, that around 1.6 ka an eco-geomorphic tipping point occurred leading to a destabilization of the landscape resulting in today’s high erosion rates and the excavation of the aged organic carbon reservoir. This study highlights the climatic and geomorphic controls on biospheric organic carbon storage and release from mountain ranges. Second, I systematically investigate the spatial variation of particulate organic carbon fluxes across the Himalaya along the Kali Gandaki River, using bulk stable and radioactive isotopes combined with a new Bayesian modeling approach. The detailed dataset allows the distinction of aged and modern biospheric organic carbon as well as petrogenic organic carbon across the Himalayan mountain range and the investigation of the role of climatic and geomorphic factors in their riverine export. The data suggest a decoupling of the particulate organic carbon from the sediment yield along the Kali Gandaki River, partially driven by climatic and geomorphic processes. In contrast to the suspended sediment, a large part of the particulate organic carbon exported by the river originates from the Tibetan part of the catchment and is dominated by petrogenic organic carbon derived from Jurassic shales with only minor contributions of modern and aged biospheric organic carbon. These findings emphasize the importance of organic carbon source distribution and erosion mechanisms in determining the organic carbon export from mountain ranges. In a third step, I explore the potential of ultra-high resolution mass spectrometry for particulate organic carbon transport studies. I have generated a novel and unprecedented high-resolution molecular dataset, which contains up to 103 molecular formulas of the lipid fraction of particulate organic matter for modern and aged biospheric carbon, petrogenic organic carbon and river sediments. First, I test if this dataset can be used to better resolve different organic carbon sources and to identify new geochemical tracers. Using multivariate statistics, I identify up to 10² characteristic molecular formulas for the major organic carbon sources in the upper part of the Kali Gandaki catchment, and trace their transfer from the surrounding landscape into the river sediment. Second, I test the potential of the molecular dataset to trace molecular transformations along source-to-sink pathways. I identify changes in molecular metrics derived from the dataset, which are characteristic of transformation processes during incorporation of litter into soil, the aging of soil material, and the mobilization of the organic carbon into the river. These two studies demonstrate that high-resolution molecular datasets open a promising analytical window on particulate organic carbon and can provide novel insights into the composition, sourcing and transformation of riverine particulate organic carbon. Collectively, these studies advance our understanding of the processes contributing to the storage and mobilization of organic carbon in the Central Himalaya, the mountain belt that dominates global erosional fluxes. They do so by identifying the major sources of particulate organic carbon to the Trans-Himalayan Kali Gandaki River, by elucidating their sensitivity to climate and geomorphic processes, and by identifying some of the transformations of this material on the molecular scale. As a result, the thesis demonstrates that the amount and composition of organic carbon routed from mountain belts is a function of the dynamic interactions of geologic, biologic, geomorphic and climatic processes within the mountain belt. This understanding will ultimately help in answering whether the build-up and erosion of mountain ranges over geological time represents a net carbon source or sink to the atmosphere. Beyond this, the thesis contributes to our technical ability to characterize organic matter and attribute it to sources by scoping the potential of high-end molecular analysis. KW - organic carbon cycle KW - biomarker KW - isotopes KW - Himalaya KW - rivers Y1 - 2020 ER - TY - JOUR A1 - Liu, Qi A1 - Adler, Karsten A1 - Lipus, Daniel A1 - Kämpf, Horst A1 - Bussert, Robert A1 - Plessen, Birgit A1 - Schulz, Hans-Martin A1 - Krauze, Patryk A1 - Horn, Fabian A1 - Wagner, Dirk A1 - Mangelsdorf, Kai A1 - Alawi, Mashal T1 - Microbial signatures in deep CO2-saturated miocene sediments of the active Hartousov mofette system (NW Czech Republic) JF - Frontiers in microbiology N2 - The Hartousov mofette system is a natural CO2 degassing site in the central Cheb Basin (Eger Rift, Central Europe). In early 2016 a 108 m deep core was obtained from this system to investigate the impact of ascending mantle-derived CO2 on indigenous deep microbial communities and their surrounding life habitat. During drilling, a CO2 blow out occurred at a depth of 78.5 meter below surface (mbs) suggesting a CO2 reservoir associated with a deep low-permeable CO2-saturated saline aquifer at the transition from Early Miocene terrestrial to lacustrine sediments. Past microbial communities were investigated by hopanoids and glycerol dialkyl glycerol tetraethers (GDGTs) reflecting the environmental conditions during the time of deposition rather than showing a signal of the current deep biosphere. The composition and distribution of the deep microbial community potentially stimulated by the upward migration of CO2 starting during Mid Pleistocene time was investigated by intact polar lipids (IPLs), quantitative polymerase chain reaction (qPCR), and deoxyribonucleic acid (DNA) analysis. The deep biosphere is characterized by microorganisms that are linked to the distribution and migration of the ascending CO2-saturated groundwater and the availability of organic matter instead of being linked to single lithological units of the investigated rock profile. Our findings revealed high relative abundances of common soil and water bacteria, in particular the facultative, anaerobic and potential iron-oxidizing Acidovorax and other members of the family Comamonadaceae across the whole recovered core. The results also highlighted the frequent detection of the putative sulfate-oxidizing and CO2-fixating genus Sulfuricurvum at certain depths. A set of new IPLs are suggested to be indicative for microorganisms associated to CO2 accumulation in the mofette system. KW - geo-bio interaction KW - CO2 KW - mofette systems KW - Eger Rift KW - microbial lipid KW - biomarker KW - microbial diversity KW - deep biosphere KW - saline groundwater Y1 - 2020 U6 - https://doi.org/10.3389/fmicb.2020.543260 SN - 1664-302X VL - 11 PB - Frontiers Media CY - Lausanne ER -