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Retrospektive Studie über den Vergleich dreier Methoden zur Detektion von Neuroblastom-Zellen im Knochenmark
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Purpose: Neuroblastoma (NB) is the most frequent extracranial tumor in children. The detection of bone marrow (BM) involvement is crucial for correct staging and risk-adapted treatment. We compared three methods regarding the detection of NB involvement in BM.
Methods: Eighty-one patients with NB were included in this retrospective study. BM samples were obtained at designated time points at study entry and during treatment or follow-up. The diagnostic tools for BM analysis included cytomorphology (CM), flow cytometry (FCM) and automatic immunofluorescence plus fluorescence in situ hybridization (AIPF).
Results: We analyzed 369 aspirates in 81 patients in whom AIPF, CM, and FCM were simultaneously available. During the observation period, NB cells were detected in 86/369 (23.3%) cases, by CM in 32/369 (8.7%), by FCM in 52 (14.1%), and by AIPF in 72 (19.5%) samples. AIPF and/or FCM confirmed all positive results obtained in CM and detected 11 additional positive BM aspirates in 294 CM negative samples (p <0,001). Survival of patients with BM involvement at study entry identified solely by FCM/AIPF was 17.4% versus 0% for patients in whom BM involvement was already identified by CM.
Conclusion :The combination of AIPF/FCM yielded the highest detection rate of NB cells in BM. AIPF was the single, most sensitive method in detecting these cells. Although CM did not provide any additional positive results, it is still a useful, readily available and cost-effective tool. The prognostic significance of FCM and AIPF should be confirmed in a prospective study with a larger number of patients
Revisiting the question “Why is the sky blue?”
Get PDFThe common answer to the question “Why is the sky blue?” is usually Rayleigh scattering. In 1953 Edward Hulburt demonstrated that Rayleigh scattering accounts for 1/3 and ozone absorption for of 2/3 the blue colour of the zenith sky at sunset. In this study, an approach to quantify the contribution of ozone to the blue colour of the sky for different viewing geometries is implemented using the radiative transfer model SCIATRAN and the CIE (International Commission on Illumination) XYZ 1931 colour system. The influence of ozone on the blue colour of the sky is calculated for solar zenith angles of 10–90∘ and a wide range of viewing geometries. For small solar zenith angles, the influence of ozone on the blue colour of the sky is minor, as expected. However, the effect of ozone increases with increasing solar zenith angle. The calculations for the Sun at the horizon confirm Hulburt's estimation with remarkably good agreement. More stratospheric aerosols reduce the ozone contribution at and near the zenith for the Sun at the horizon. The exact contribution of ozone depends strongly on the assumed total ozone column. The calculations also show that the contribution of ozone increases with increasing viewing zenith angle and total ozone column. Variations in surface albedo as well as full treatment of polarised radiative transfer were found to have only minor effects on the contribution of ozone to the blue colour of the sky. Furthermore, with an observer at 10 km altitude an increase in the ozone influence can be seen
Do in-person and computer-based brief alcohol interventions reduce tobacco smoking among general hospital patients? Secondary outcomes from a randomized controlled trial
Get PDFBackground
At-risk alcohol use and tobacco smoking often co-occur. We investigated whether brief alcohol interventions (BAIs) among general hospital patients with at-risk alcohol use may also reduce tobacco smoking over 2 years. We also investigated whether such effects vary by delivery mode; i.e. in-person versus computer-based BAI.
Methods
A proactively recruited sample of 961 general hospital patients with at-risk alcohol use aged 18 to 64 years was allocated to three BAI study groups: in-person BAI, computer-based BAI, and assessment only. In-person- and computer-based BAI included motivation-enhancing intervention contacts to reduce alcohol use at baseline and 1 and 3 months later. Follow-ups were conducted after 6, 12, 18 and 24 months. A two-part latent growth model, with self-reported smoking status (current smoking: yes/no) and number of cigarettes in smoking participants as outcomes, was estimated.
Results
Smoking participants in computer-based BAI smoked fewer cigarettes per day than those assigned to assessment only at month 6 (meannet change = − 0.02; 95% confidence interval = − 0.08–0.00). After 2 years, neither in-person- nor computer-based BAI significantly changed smoking status or number of cigarettes per day in comparison to assessment only or to each other (ps ≥ 0.23).
Conclusions
While computer-based BAI also resulted in short-term reductions of number of cigarettes in smoking participants, none of the two BAIs were sufficient to evoke spill-over effects on tobacco smoking over 2 years. For long-term smoking cessation effects, multibehavioural interventions simultaneously targeting tobacco smoking along with at-risk alcohol use may be more effective.
Trial registration number: NCT01291693
The Impact of Fluorination on the Design of Histone Deacetylase Inhibitors
Get PDFIn recent years, histone deacetylases (HDACs) have emerged as promising targets in the treatment of cancer. The approach is to inhibit HDACs with drugs known as HDAC inhibitors (HDACis). Such HDACis are broadly classified according to their chemical structure, e.g., hydroxamic acids, benzamides, thiols, short-chain fatty acids, and cyclic peptides. Fluorination plays an important role in the medicinal–chemical design of new active representatives. As a result of the introduction of fluorine into the chemical structure, parameters such as potency or selectivity towards isoforms of HDACs can be increased. However, the impact of fluorination cannot always be clearly deduced. Nevertheless, a change in lipophilicity and, hence, solubility, as well as permeability, can influence the potency. The selectivity towards certain HDACs isoforms can be explained by special interactions of fluorinated compounds with the structure of the slightly different enzymes. Another aspect is that for a more detailed investigation of newly synthesized fluorine-containing active compounds, fluorination is often used for the purpose of labeling. Aside from the isotope 19F, which can be detected by nuclear magnetic resonance spectroscopy, the positron emission tomography of 18F plays a major role. However, to our best knowledge, a survey of the general effects of fluorination on HDACis development is lacking in the literature to date. Therefore, the aim of this review is to highlight the introduction of fluorine in the course of chemical synthesis and the impact on biological activity, using selected examples of recently developed fluorinated HDACis
Synthesis of Modified Poly(vinyl Alcohol)s and Their Degradation Using an Enzymatic Cascade
Get PDFPoly(vinyl alcohol) (PVA) is a water‐soluble synthetic vinyl polymer with remarkable physical properties including thermostability and viscosity. Its biodegradability, however, is low even though a large amount of PVA is released into the environment. Established physical‐chemical degradation methods for PVA have several disadvantages such as high price, low efficiency, and secondary pollution. Biodegradation of PVA by microorganisms is slow and frequently involves pyrroloquinoline quinone (PQQ)‐dependent enzymes, making it expensive due to the costly cofactor and hence unattractive for industrial applications. In this study, we present a modified PVA film with improved properties as well as a PQQ‐independent novel enzymatic cascade for the degradation of modified and unmodified PVA. The cascade consists of four steps catalyzed by three enzymes with in situ cofactor recycling technology making this cascade suitable for industrial applications
Coupling Pyrazine to Dithiocarbonates for Molybdopterin Model Ligands—Indispensable Tin
Get PDFSeveral synthetic cross-coupling procedures were (re-)evaluated for the tethering of pyrazine to dithiocarbonates. The resultant species constitute pro-ligands and can be converted by removal of the C=O moiety into ene-dithiolate ligand systems that model molybdopterin. The coupling of 2-iodopyrazine with the stannylated dithiocarbonate units mediated by copper(I)-thiophene-2-carboxylate in stoichiometric equivalents proved to be the most efficient and the only reliable route to the targeted compounds. Single-crystal X-ray structural analysis confirmed the final structures of two pursued pyrazine-derived dithiocarbonates and those of two intermediates
The Ins and Outs of Urea: Identification of Putative DUR3-like Urea Transporters in the Oligohaline Nerite Snail Theodoxus fluviatilis and Their Expression under Changing Salinities
Get PDFTheodoxus fluviatilis (Linnaeus, 1758) (Gastropoda: Neritidae) is an oligohaline aquatic gastropod that inhabits most of Europe and adjacent areas of Asia. Two different ecotypes can be distinguished: One in freshwater (FW) and another along the Baltic Sea coast in brackish water habitats (BW). Individuals of either ecotype use free amino acids and urea as organic osmolytes to adjust body fluid osmolality to the external medium; however, the BW ecotype is able to accumulate them in larger quantities. The use of urea as an organic osmolyte in aquatic gastropods such as T. fluviatilis has only recently been initially described and raised the question of how urea transport between body fluids and the environment is balanced. Upon examining transcriptome and preliminary genome sequence data of T. fluviatilis, we identified putative homologues of DUR3 genes, which code for urea transporters (UTs) in other organisms. In this study, we provide evidence for the presence of four different subtypes of DUR3-like UTs that belong to two distinct families. Two of the UT subtypes were subject to qRT-PCR analyses to investigate differences in mRNA expression during the acclimation of individuals of both ecotypes to different salinities. Our results indicate that only BW animals regulate DUR3 gene expression in the context of osmoregulation
Nutritional Composition, Fatty Acids Profile, Mineral Content, Antioxidant Activity and Acute Toxicity of the Flesh of Helix aspersa Müller
Get PDFHumans consume snail flesh as part of their diet. To assess its nutritional value and toxicity, chemical analyses were conducted to confirm the presence of protein, total and reduced carbohydrates, fat, fatty acid composition and mineral components. Furthermore, an acute toxicity study was carried out to determine the safety of Helix aspersa Müller snail flesh. H. aspersa Müller snail flesh exhibits a high nutritional content, a good ω3/ω6 ratio and higher levels of unsaturated fatty acids. Various minerals have been found in the flesh of H. aspersa Müller. Around 76.91 kcal, or 3.84% of the energy of a daily meal of 2000 kcal, are present in 100 g of this flesh. The evaluation of the antioxidant capacity indicated that the flesh’s extracts contained a large quantity of antioxidant biomolecules. Administration of the aqueous extract of H. aspersa Müller flesh didn’t cause death in laboratory rats, indicating that the lethal dose 50 is greater than 2000 mg·kg−1 body weight. The consumption of the flesh of H. aspersa Müller is highly recommended for human consumption due to its high concentration of nutrients and essential elements, as well as unsaturated fats, and due to its safety
Semantic or Affective Primacy? Perceptual Latencies of Object Recognition and Affect Measured With Temporal Judgments and Speeded Reaction Time Tasks
Get PDFA long-standing controversy in emotion research concerns the question whether stimuli must be conceptually interpreted, or semantically categorized, to evoke emotional reactions. According to the semantic primacy hypothesis, the answer to this question is positive; whereas according to the affective primacy hypothesis, it is negative: Emotions can also be, and perhaps often are, elicited by preconceptual stimulus representations, such as particular shapes or color patterns.
In the present dissertation project, the semantic primacy hypothesis was tested in eight experiments using different latency judgment paradigms in which the perceptual latencies of object recognition and affect onset were measured and compared. The chronometric measurement methods comprised temporal judgments (temporal order judgments and simultaneity judgments: Publication A, Experiments 1–4; the rotating spot / rotating clock hand method: Publication B, Experiments 1–2) and speeded reaction time measurements (Publication C, Experiments 1–2). To elicit affective responses, pictures of pleasant (e.g., cats, children) and unpleasant objects (e.g., spiders, moldy food) from everyday life were presented.
According to the semantic primacy hypothesis, object recognition is a necessary partial cause of affect. This implies the following three predictions that were tested in the studies: (1) Because causes must precede their effects, the time of the onset of object recognition must precede the time of the onset of affect. (2) The longer it takes a person to recognize an object, the longer it should also take them, other factors constant, to experience affect; therefore, the latencies of the two mental events should be positively correlated across individuals. (3) An experimental manipulation that delays the onset of object recognition (in this case a moderate blurring of the pictures) should also delay the onset of affect, and the effect of the manipulation on affect latency should be mediated by the delay in object recognition.
In agreement with Prediction 1, regardless of the chronometric method used, the latency of object recognition consistently proved to be shorter than the latency of affect onset. According to the meta-analytically integrated latency differences estimated in the temporal judgment experiments, affect followed object recognition with a delay of 117 ms. This result was obtained for both pleasant and unpleasant stimuli and was independent of task order. Supporting Prediction 2, the latencies for object recognition and affect onset were positively correlated across participants (meta-analytic r = .50). Supporting Prediction 3, delaying object recognition by blurring the affective pictures was found to also delay the onset of affect and the effect of blurring on the latency of affect was found to be partly mediated by delayed object recognition.
Two additional predictions tested and confirmed in Experiment C2 were: (4) False-coloring the affective pictures delays the onset of affect but not object recognition, and this effect is mediated by reduced affect intensity. (5) Judgments of the valence of the stimuli (i.e., whether the imaged object is pleasant or unpleasant) take more time than reports of object recognition, but less time than affect onset reports, for which valence judgments have often been used as a substitute in previous studies.
Taken together, the results of the eight experiments provided consistent support for semantic primacy in the generation of pleasant and unpleasant feelings evoked by affective pictures: Object recognition can be considered a necessary partial cause of affect in the reported experiments. The results are compared to previous findings, possible reasons for deviant response patterns found in a small minority of the participants are considered, and several implications of the findings for emotion research are derived. Possible adaptations of the chronometric approach to investigate other questions of emotion research are suggested. Finally, limitations of the dissertation project are pointed out and possible ways to address these in future research are proposed.Eine seit langem bestehende Kontroverse in der Emotionsforschung betrifft die Frage, ob Stimuli konzeptuell interpretiert oder semantisch kategorisiert werden müssen, um emotionale Reaktionen hervorzurufen. Nach der Hypothese des semantischen Primats (Semantic-Primacy-Hypothese) ist diese Frage positiv zu beantworten; nach der Hypothese des affektiven Primats (Affective-Primacy-Hypothese) hingegen ist sie negativ zu beantworten: Emotionen können auch durch präkonzeptuelle Stimulusrepräsentationen, wie z. B. bestimmte Formen oder Farbmuster, ausgelöst werden – und werden es vermutlich sogar oft.
Die Semantic-Primacy-Hypothese wurde im Rahmen dieses Dissertationsprojekts in acht Experimenten anhand von verschiedenen Latenzmessungsparadigmen getestet, in denen die Wahrnehmungslatenzen von Objekterkennung einerseits und von Affektauslösung andererseits gemessen und miteinander verglichen wurden. Die chronometrischen Messmethoden umfassten temporale Urteile (Temporal Order Judgments und Simultaneity Judgments: Publikation A, Experimente 1–4; die Rotating-Spot- bzw. Uhrzeigermethode: Publikation B, Experimente 1–2) sowie Reaktionszeitmessungen (Publikation C, Experimente 1–2). Um affektive Reaktionen hervorzurufen, wurden Bilder von angenehmen (z. B. Katzen, Kinder) und unangenehmen Objekten (z. B. Spinnen, verdorbene Lebensmittel) aus dem alltäglichen Leben präsentiert.
Nach der Semantic-Primacy-Hypothese ist die Objekterkennung eine notwendige Teilursache des Affekts. Dies impliziert die folgenden drei Vorhersagen, die in den Studien getestet wurden: (1) Da im Sinne der Kausalität Ursachen ihren Wirkungen vorausgehen, muss der Zeitpunkt des Einsetzens der Objekterkennung vor dem Zeitpunkt des Affekts liegen. (2) Je länger eine Person braucht, um ein Objekt zu erkennen, desto länger sollte sie, unter Konstanz aller anderen Faktoren, auch brauchen, um einen Affekt zu erleben; daher sollten die Latenzen der beiden mentalen Ereignisse ̈uber alle Personen hinweg positiv korreliert sein. (3) Eine experimentelle Manipulation, die das Einsetzen der Objekterkennung verzögert (wir wendeten einen moderaten Unschärfefilter auf die affektiven Bilder an), sollte auch das Einsetzen des Affekts verzögern und der Effekt der Manipulation auf den Affekt sollte wiederum durch die Verzögerung der Objekterkennung mediiert sein.
In Übereinstimmung mit Vorhersage 1 war die Latenzzeit der Objekterkennung unabhängig von der verwendeten chronometrischen Methode durchweg kürzer als die Latenzzeit des Affekts. Den meta-analytisch integrierten Latenzdifferenzen entsprechend, die in den Experimenten mit temporalen Urteilen geschätzt wurden, folgte der Affekt 117 ms nach der Objektrekognition. Dieses Ergebnis zeigte sich sowohl für angenehme als auch für unangenehme Stimuli und war unabhängig von der Aufgabenreihenfolge. Wie durch Vorhersage 2 nahegelegt, waren die Latenzen von Objekterkennung und Affekt über alle Versuchspersonen hinweg positiv korreliert (meta-analytisches r = .50). Vorhersage 3 stützend wurde festgestellt, dass die Verzögerung der Objekterkennung durch Anwendung des Unschärfefilters auf die affektiven Bilder auch das Auftreten des Affekts verzögert und dass der Effekt des Unschärfefilters auf die Latenz des Affekts teilweise durch die verzögerte Objekterkennung mediiert ist.
Zwei weitere Vorhersagen wurden in Experiment C2 getestet und bestätigt: (4) Eine Falscheinfärbung der affektiven Bilder verzögert das Einsetzen des Affekts, aber nicht die Objekterkennung, und dieser Effekt wird durch eine verringerte Affektintensität mediiert. (5) Urteile über die Valenz der Stimuli (d. h., ob das abgebildete Objekt angenehm oder unangenehm ist) benötigen mehr Zeit als Berichte über die Objekterkennung, aber weniger Zeit als Berichte über das Einsetzen des Affekts. Für Berichte des Einsetzens des Affekts wurden Valenzurteile in früheren Studien oft stellvertretend herangezogen.
Zusammengenommen unterstützen die Ergebnisse der acht Experimente konsistent die Semantic-Primacy-Hypothese der Entstehung angenehmer und unangenehmer Gefühle durch affektive Bilder: Objektrekognition kann als notwendige Teilursache des Affekts in den berichteten Experimenten betrachtet werden. Die Ergebnisse werden mit früheren Befunden verglichen, mögliche Gründe für abweichende Ergebnisse bei einer kleinen Gruppe der Versuchspersonen erörtert und verschiedene Implikationen der Ergebnisse für die Emotionsforschung abgeleitet. Mögliche Anpassungen des chronometrischen Ansatzes zur Untersuchung anderer Fragestellungen in der Emotionsforschung werden vorgeschlagen. Abschließend wird auf die Grenzen des Dissertationsprojekts eingegangen und es werden Möglichkeiten vorgeschlagen, wie diese in zukünftiger Forschung adressiert werden können
The soil microbiome as a driver of methane fluxes in temperate grassland and forest soils
Get PDFMethane (CH4) is a potent greenhouse gas with rising atmospheric concentrations.
Microorganisms are essential players in the global methane cycle. In fact, the largest part of methane emissions derives from microbial production by methanogenic Archaea (methanogens). Microorganisms do not only produce methane: methanotrophs can also oxidize the methane produced by methanogens. In addition, soil methanotrophs are the only biological methane sink, oxidizing up to 30-40 Tg of this potent greenhouse gas per year worldwide.
However, intensified management of grasslands and forests may reduce the methane sink capacity of soils.
In general, the interaction of methanogens and methanotrophs determines whether a soil is a source or a sink for methane. It is, therefore, crucial to understand the microbial part of the methane cycle and which factors influence the abundance and activity of methane-cycling microbes. However, capturing the soil microbiome's abundances, activity, and identity is
challenging. There are numerous target molecules and myriad methods, each with certain
limitations. Linking microbial markers to methane fluxes is therefore challenging. This thesis aimed to understand how methane-cycling microbes in the soil are related to soil methane fluxes and how soil characteristics and human activity influence them.
The first publication investigated the biotic and abiotic drivers of the atmospheric methane sink of soils. It assessed the influence of grassland land-use intensity (150 sites) and forest management type (149 sites) on potential atmospheric methane oxidation rates (PMORs) and the abundance and diversity of CH4-oxidizing bacteria (MOB) with qPCR in topsoils of three temperate regions in Germany. PMORs measured in microcosms under defined conditions were approximately twice as high in forest than in grassland soils. High land-use intensity of grasslands negatively affected PMORs (−40%) in almost all regions. Among the different aspects of land-use intensity, fertilization had the most adverse effect reducing PMORs by 20%.
In contrast, forest management did not affect PMORs in forest soils. Upland soil cluster (USC)α was the dominant group of MOBs in the forests. In contrast, USCγ was absent in more than half of the forest soils but present in almost all grassland soils. USCα abundance had a direct positive effect on PMOR in forests, while in grasslands, USCα and USCγ abundance affected PMOR positively with a more pronounced contribution of USCγ than USCα.
In the second publication, we used quantitative metatranscriptomics to link methane-cycling microbiomes to net surface methane fluxes throughout a year in two grassland soils. Methane fluxes were highly dynamic: both soils were net methane sources in autumn and winter and net methane sinks in spring and summer. Correspondingly, methanogen mRNA abundances per
gram soil correlated well with methane fluxes. Methanotroph to methanogen mRNA ratios were higher in spring and summer when the soils acted as net methane sinks. Furthermore, methane uptake was associated with an increased proportion of USCα and γ pmoA and pmoA2 transcripts. High methanotroph to methanogen ratios would indicate methane sink properties.
Our study links the seasonal transcriptional dynamics of methane-cycling soil microbiomes for the first time to gas fluxes in situ. It suggests mRNA transcript abundances as promising indicators of dynamic ecosystem-level processes.
We conclude that reduction in grassland land-use intensity and afforestation can potentially increase the methane sink function of soils and that different parameters determine the microbial methane sink in forest and grassland soils. Furthermore, this thesis suggests mRNA transcript abundances as promising indicators of dynamic ecosystem-level processes. Methanogen transcript abundance may be used as a proxy for changes in net surface methane emissions from grassland soils.Methan (CH4) ist ein starkes Treibhausgas mit steigenden atmosphärischen Konzentrationen.
Mikroorganismen sind wesentliche Akteure im globalen Methankreislauf. Tatsächlich stammt
der größte Teil der Methanemissionen aus der mikrobiellen Produktion durch methanogene
Archaeen (Methanogene). Mikroorganismen produzieren nicht nur Methan: Methanotrophe
Organismen können das von Methanogenen produzierte Methan auch oxidieren. Darüber
hinaus sind Methanotrophe im Boden die einzige biologische Methansenke, die bis zu 30-40
Tg dieses starken Treibhausgases pro Jahr oxidiert. Eine intensivere Bewirtschaftung von
Grünland und Wäldern kann jedoch die Kapazität der Böden als Methansenke verringern.
Im Allgemeinen bestimmt das Zusammenspiel von Methanogenen und Methanotrophen, ob ein
Boden eine Quelle oder eine Senke für Methan ist. Daher ist es wichtig den mikrobiellen Teil
des Methankreislaufs zu kennen um zu verstehen, welche Faktoren die Häufigkeit und Aktivität
der methanbildenden Mikroben beeinflussen. Die Abundanz, Aktivität und Identität des
Bodenmikrobioms zu bestimmen ist jedoch sehr anspruchsvoll. Es gibt zahlreiche Zielmoleküle
und eine Vielzahl von Methoden, die jeweils bestimmte Einschränkungen aufweisen. Die
Verknüpfung von mikrobiellen Markern mit Methanflüssen ist daher eine Herausforderung.
Ziel dieser Arbeit war es, zu verstehen, wie Bodenmikroben mit Methanflüsse von Böden
zusammenhängen und wie sich Bodeneigenschaften und menschliche Aktivitäten auf die
Methanflüsse von Böden auswirken.
In der ersten Veröffentlichung wurden die biotischen und abiotischen Faktoren untersucht, die
die atmosphärische Methansenke der Böden beeinflussen. Dabei wurden die Auswirkungen der
Intensität der Grünlandnutzung (150 Standorte) und der Art der Waldbewirtschaftung (149
Standorte) auf die potenziellen atmosphärischen Methanoxidationsraten (PMORs) sowie die
Häufigkeit und Vielfalt von methanoxidierenden Bakterien (MOB) mit qPCR in Proben von
Oberböden aus drei gemäßigten Regionen in Deutschland untersucht. Die in Mikrokosmen
unter definierten Bedingungen gemessenen PMORs waren in Waldböden etwa doppelt so hoch
wie in Grünlandböden. Die hohe Landnutzungsintensität von Grünland wirkte sich in fast allen
Regionen negativ auf die PMOR-Werte aus (-40 %). Von den verschiedenen Aspekten der
Landnutzungsintensität wirkte sich die Düngung am stärksten negativ aus und verringerte die
PMORs um 20 %. Im Gegensatz dazu hatte die Waldbewirtschaftung keinen Einfluss auf die
PMORs in Waldböden. Das Upland Soil Cluster (USC)α war die dominierende Gruppe von
MOBs in den Wäldern. Im Gegensatz dazu fehlte USCγ in mehr als der Hälfte der Waldböden,
war aber in fast allen Grünlandböden vorhanden. Die Abundanz von USCα wirkte sich in
Wäldern direkt positiv auf PMOR aus, während sich im Grasland die Abundanz von USCα und
USCγ positiv auf PMOR auswirkte, wobei der Beitrag von USCγ stärker war als der von USCα.
In der zweiten Veröffentlichung setzten wir quantitative Metatranskriptomik ein, um die
Methan-zyklierenden Mikrobiome mit den Nettomethanflüssen zweier Graslandböden über ein
Jahr hinweg zu verbinden. Die Methanflüsse waren sehr dynamisch: Beide Böden waren im
Herbst und Winter Nettomethanquellen und im Frühjahr und Sommer Nettomethansenken.
Dementsprechend korrelierten die mRNA-Häufigkeiten der Methanogene pro Gramm Boden
gut mit den Methanflüssen. Das Verhältnis von Methanotrophen zu Methanogenen mRNA war
im Frühjahr und Sommer höher, wenn die Böden eine Nettomethansenken waren. Außerdem
war die Methanaufnahme mit einem erhöhten Anteil an USCα- und γ pmoA- und pmoA2-
Transkripten verbunden. Die Methanaufnahme der Böden war von einem hohen Verhältnis von
Methanotrophen zu Methanogenen begleitet. Diese Thesis stellt erstmals einen Zusammenhang
zwischen der saisonalen Transkriptionsdynamik von Methan-zyklierenden Bodenmikrobiomen
und den Gasflüssen in situ her.
Wir kommen zu dem Schluss, dass eine Verringerung der Intensität der Grünlandnutzung und
Aufforstung die Methansenkenfunktion von Böden potenziell erhöhen kann und dass
unterschiedliche Parameter die mikrobielle Methansenke in Wald- und Grünlandböden
bestimmen. Darüber hinaus zeigt diese Arbeit, dass die Abundanz von mRNA Transkripten ein
vielversprechender Indikator für dynamische Prozesse auf Ökosystemebene sein können. Die
Abundanz von Methanogen-Transkripten kann als Indikator für Veränderungen der Netto-
Oberflächen-Methanemissionen von Grünlandböden verwendet werden