Open Access

Objective: Edema and subjective leg complaints, such as pain, tightness, tiredness and heaviness after long standing or sitting, are defined as orthostatic leg complaints or occupational edema. Compression hosiery should help to prevent or decrease those symptoms. The objective was to assess the effects on leg discomforts and leg volume, and wearing comfort in two medical below-knee compression stocking types with an interface pressure of 18 – 20 mmHg (A vs. B) and a below-knee-low-pressure support stocking (LPSS) with an interface pressure of 8-10mmHg (C). Methods: Two different types of below-knee medical compression stockings with an interface pressure of 18 – 20 mmHg (A vs. B) and a below-knee-low-pressure support stocking (LPSS) with an interface pressure of 8-10mmHg (C) were examined in this randomized, blinded, crossover trial (RCT) with 49 healthy volunteers having leg discomforts and edema after being in an upright position during the day. Stocking Type B had special fabrication properties in the in heel and instep-area of the foot. Participants were divided into two cohorts, and each type of stocking was worn for three consecutive days in one week with a subsequent washout phase. The cohorts were named after the respective sequence of the wearing period (ABC/BAC). The assessment of effects and wearing comfort was ascertained by questionnaires. Volume changes in the lower leg were measured with the Bodytronic 600® (Bauerfeind AG, Zeulenroda, Germany). Results: A significant reduction of lower leg volume (mean Stocking Type A: 204.7 ml; mean Stocking Type B: 153.5 ml; mean stocking type C: 48.2ml) and a significant reduction of the life-quality dimension (LQD) leg-complaints (p = 0.0000) was achieved by all three types of stockings. Compared to the LPSS both compression stockings had a significant better fit (p<0.006). Conclusion: Below-knee medical compression stockings with an interface pressure 18-21mmHg and LPSS with an interface pressure of 8-10 mmHg can significantly reduce occupational orthostatic edema and leg discomforts which are due to long standing and sitting activities. Because of the custom fit, medical below-knee compression stockings are having a significant better wearing comfort than commercial LPSS and should be preferred when prescribing compression stockings to prevent occupational edema.

Methane (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.

Ödeme, die durch Orthostase verursacht werden, sind im medizinischen und beruflichen Kontext ein häufiges Krankheitsbild. Die Volumenzunahme in den Unterschenkeln und die damit verbunden Beschwerden treten insbesondere in Berufen auf, die mit langem Stehen und wenig Bewegung verbunden sind. Bisher ungeklärt ist, ob es einen Zusammenhang zwischen der Zunahme des Unterschenkelvolumens und der Entstehung von Missempfindungen bei Stehbelastungen gibt. Ebenfalls fraglich ist, ob die während einer Orthostase entstehenden Missempfindungen durch die Durchführung bestimmter Bewegungen beeinflusst werden können. Ziel dieser nicht-randomisierten, kontrollierten Studie war es, die Veränderungen und den zeitlichen Zusammenhang von einer V olumenzunahme und dem Auftreten von Beschwerden in den Unterschenkeln während einer Stehbelastung zu untersuchen. Dabei wurde durch die Probanden eine zeitlich begrenzte Stehbelastung von 15 min absolviert. Im Rahmen dessen wurde das Unterschenkelvolumen mit einem optischen dreidimensionalen Volumenmesssystem gemessen. Die aufgetretenen Missempfindungen und der Bewegungsdrang wurden anhand einer numerischen Rating- Skala (NRS) von null bis zehn Punkten abgefragt. Es wurde eine Korrelationsanalyse zwischen dem Unterschenkelvolumen und den Daten zu den Missempfindungen und dem Bewegungsdrang der einzelnen Probanden durchgeführt. Darüber hinaus wurden lineare Modelle mit gemischten Effekten berechnet, um das Vorhandensein einer kausalen Beziehung zwischen dem Unterschenkelvolumen und den Missempfindungen oder dem Bewegungsdrang im Stehen zu untersuchen. Die Stehversuche wurden ein zweites Mal durchgeführt, während die Probanden MKS trugen. Als Resultat konnte gezeigt werden, dass das Unterschenkelvolumen während der Stehphase ohne MKS durchschnittlich um 63 ml und mit MKS um 27 ml zu nahm (p < 0,001). Die Missempfindungen stiegen während der Orthostase ohne MKS im Mittel um 3,46 Punkte auf der NRS und mit MKS um 2,6 Punkte (p < 0,001). Der Bewegungsdrang der Teilnehmer erhöhte sich während der Stehphase ohne MKS um 3,47 Punkte auf der NRS und mit MKS um 3,73 Punkte (p < 0,001). Ein signifikanter Zusammenhang zwischen der Zunahme des Unterschenkelvolumens und dem Auftreten von Missempfindungen bzw. von Bewegungsdrang wurde bei der Mehrzahl der Probanden ohne MKS (p < 0,05) und mit MKS (p < 0,1) festgestellt. In den linear gemischten Modellen zeigte sich ein kausaler Zusammenhang zwischen der Volumenzunahme der Unterschenkel und dem Auftreten der Symptome (p < 0,001). Schlussendlich lässt sich feststellen, dass längeres Stehen mit Bewegungsmangel bei venengesunden Probanden zu einer Zunahme des Unterschenkelvolumens und zu einem Gefühl von Unbehagen führt. Durch einstudierte Bewegungen und das Tragen von MKS können unter kontrollierten Bedingungen die Missempfindungen in den Beinen und teilweise auch das Unterschenkelvolumen reduziert werden. Lineare Modelle mit gemischten Effekten weisen auf kausale Zusammenhänge zwischen diesen Variablen hin. Aufgrund der Schwierigkeit, subjektive Äußerungen über Beschwerden mit objektiven Messergebnissen wie der Volumenzunahme zu korrelieren, sind jedoch weitere Studien erforderlich, die auch Stoffwechselprozesse auf molekularbiologischer Ebene miteinbeziehen.

Tafazzin is an acyltransferase with key functions in remodeling of the mitochondrial phospholipid cardiolipin (CL) by exchanging single fatty acids species in CL. Tafazzin-mediated CL remodeling determines the actual CL compositions and has been implicated in mitochondrial morphology and function. Thus, any deficiency of tafazzin leads to altered fatty acid composition of CL which is directly associated with impaired mitochondrial respiration and ATP production. Mutations in the tafazzin encoding gene TAZ, are the cause of the severe X-linked genetic disease, BARTH syndrome (BTHS). Previous work provided first hints on a linkage of CL composition and subsequent limitations in the cellular ATP levels which may contribute to the restriction of growth. However, in C6 cells ATP levels remained unaltered due to compensatory activation of glycolysis. Moreover, it has been demonstrated that the substantial changes in CL composition are similarly resulting from knocking down either cardiolipin synthase (CRLS) or TAZ. This has also been shown in C6 glioma cells. Most notably only the knock down of TAZ, but not that of CRLS, compromised proliferation of C6 glioma cells. Therefore, a CL- independent role of TAZ in regulating cell proliferation is postulated. In this study, any linkage of the lack of tafazzin to cellular proliferation should be investigated in more detail to allow first insight into underlying mechanisms. The results of the current study demonstrate that the tafazzin knockout in C6 glioma cells show changes in global gene expression by applying transcriptome analysis using the- microarray Clarion S rat Affymetrix array. Out of 22,076 total number of genes detected, 1,099 genes were differentially expressed in C6 knockout cells which were either ≥2 and ≥4 fold up or down regulated genes. Furthermore, expression of selected target genes was validated using RT-qPCR. We have hypothesised that the changes in TAZ dependent gene expression is via PPAR transcription factor. According to eukaryotic promoter database (EPD) for selected target genes, exhibited at least one putative binding site for PPARG and PPARA transcription factors. However, pioglitazone and LG100268, synthetic ligands of PPARG and RXR, could not show any effect on changes in gene expression in C6 TAZ cells. Another class of cellular lipids, oxylipins were found to occur in significantly higher amounts in C6 TAZ cells compared to C6 cells which makes them candidates for mediating cellular effects and regulating gene expression via PPARs. A computational tool CiiiDER was used to for the prediction of transcription factor binding site. The transcription factors enriched in TAZ- regulated genes were found to be HOXA5 and PAX2, binding sites of which could be detected in 100 % of TAZ- regulated genes (>2-fold). By applying IPA to the differentially expressed genes we could identify lipid metabolism, and cholesterol superpathway in particular as the most affected pathway in C6 TAZ cells. This pathway consists of 20 genes, of which all (20/20) appeared to be differentially regulated in C6 TAZ cells. Of all the 20 genes, 4 of the differentially expressed genes were selected for further validation by RT-qPCR. By IPA it was possible to identify the upstream regulators that might be responsible for the differential expression of genes in C6 deficient cells. Some of the genes ACACA, HMGCR, FASN, ACSL1, 3 and, 5 identified was decreased by predicted activation and inhibition of the regulators. Further we have analysed the levels of cellular cholesterol content in C6 and C6 TAZ (w/o Δ5 and FL) cells. In C6 cells cholesterol is present more in its free form. C6 TAZ cells have increased amount of cholesterol compared to C6 cells. However, Δ5 and FL expressed C6 TAZ cells showed less amount of cholesterol. Previous work established that knockout of tafazzin in C6 cells showed decreased cell proliferation in the absence of any changes in ATP content. To understand this phenomenon cellular senescence associated β-galactosidase in C6 and C6 TAZ cells was performed. C6 TAZ cells showed increased percentage of β-gal positive cells compared to C6 cells. Moreover, senescent associated secretory phenotype (SASP) represented by e.g. CXCL1, IL6, and IL1α was determined using RT-qPCR. Gene expression of these SASP factors was significantly upregulated in C6 TAZ cells. Several human tafazzin isoforms exists due to alternate splicing. However, whether these isoforms differ in function and in CL remodelling activity or specificity, in particular, is unknown. The purpose of this work was to determine if specific isoforms, such as human isoform lacking exon 5 (Δ5), rat full length tafazzin (FL) and enzymatically dead full length tafazzin (H69L), can restore the wild type phenotype in terms of CL composition, cellular proliferation, and gene expression profile. Therefore, in the second part, it was demonstrated that expression of Δ5 to some extent and rat full length tafazzin can completely restore CL composition, in C6 TAZ cells which is naturally linked to the restoration of mitochondrial respiration. As expected, a comparable restoration of CL composition could not be seen after re-expressing an enzymatically dead full-length rat TAZ, (H69L; TAZ Mut). Furthermore, re-expression of the TAZ Mut largely failed to reverse the alterations in gene expression, in contrast re-expression of the TAZ FL and the Δ5 isoforms reversed gene expression to a larger extent. Moreover, only rat full length TAZ was able to reverse proliferation rate. Surprisingly, the expression of Δ5 in C6 TAZ cells did not promote proliferation of the wild type. Different effects of Δ5 and FL on CL composition and cell proliferation points to the specific and in part non-enzymatic functions of tafazzin isoforms, but this certainly requires further analysis.

In welcher Beziehung stehen Schmuckobjekte zur eigenen Persönlichkeit? Mit welchen Erinnerungen, Erzählungen und Projektionen sind sie verbunden? Ausgehend vom Hiddenseer Goldschmuck, ein heute im Stralsund Museum bewahrtes Schatzkonvolut aus der Wikingerzeit, führen diese und weitere Fragen Schüler*innen an Vorstellungen von kulturellem Erbe, Identität und regionaler Zugehörigkeit heran. Wikingergold – eine Auseinandersetzung mit kulturellem Erbe und Identitäten im Kunstunterricht richtet sich an Schüler*innen der 7. bis 10. Klasse und ist fachübergreifend nutzbar. Drei Arbeitspakete – „Der Hiddenseer Goldschmuck“, „Goldschätze aus der Wikingerzeit – Kulturerbe des Ostseeraums“ und „‚Wikinger‘ darstellen und ausstellen“ – können komplementär, aber auch einzeln bearbeitet werden. Jedes enthält einen Einführungstext, Vorschläge zur Unterrichtskonzeption und Arbeitsblätter. Neben Text- und Bildmaterial kann ein eigens für das Projekt entwickelter Kurzfilm betrachtet oder eine digitale Ausstellung besucht werden. Ziel der Unterrichtsmaterialien ist es, Verbindungen von Geschichte und Geschichtsmythen mit dem Alltag der Schüler*innen aufzuzeigen und zu reflektieren. „Wikingerschmuck“ wird so zum Instrument der Reflexion des eigenen Selbstbildes und er kann Anstoß für identitätsbildende Prozesse sein.