In Sachsen wurden bisher 76 Arten Eintagsfliegen nachgewiesen. In der Artenliste und Roten Liste sind sie zusammengestellt und bewertet. Die Rote Liste informiert über die Gefährdungssituation der Arten und Lebensräume und stellt eine Grundlage für die Fachplanung im Naturschutz dar. Rote Listen werden regelmäßig aktualisiert. Ein kommentiertes Verzeichnis der Eintagsfliegen erschien in Sachsen zuletzt im Jahr 2002.

In Sachsen sind bisher 521 Zieralgen-Arten nachgewiesen. In der Artenliste und Roten Liste sind sie zusammengestellt und bewertet. Die Rote Liste informiert über die Gefährdungssituation der Arten und Lebensräume. Zieralgen sind gute Indikatoren für die Gewässergüte und spielen eine Rolle in den Bewertungsverfahren der Wasserrahmenrichtlinie. Die Artenliste und Rote Liste der Zieralgen in Sachsen wurde erstmals erstellt.

Cre-mediated site-specific recombination has emerged as an indispensable tool for the precise manipulation of genomes allowing lineage-tracing studies, temporal and spatial misexpressions, and in particular the generation of conditional knockout alleles. Previously, we and others showed that Cre and its ligand-inducible variant CreERT2 are also highly efficient in the developing and adult zebrafish. The number of Cre driver and effector lines is currently still limited in zebrafish. However, the recent advent of novel genome editing tools such as TALEN and CRISPR/Cas will significantly increase interest in the conditional Cre/lox-technology in this organism. The considerations of basic transgene design and subsequent transgenesis have been addressed elsewhere. Here we outline practical experimental steps for transient functionality tests of CreERT2 driver and effector constructs. In addition, we introduce detailed protocols to elicit CreERT2-mediated recombination in vivo at embryonic as well as adult stages.

Transfer RNA nucleotidyltransferases (CCA-adding enzymes) are important enzymes, which catalyze the attachment of a CCA triplet to the 3‘ end of tRNAs, an essential requirement for subsequent aminoacylation. These special enzymes function in a fascinating manner without a nucleic acid template. Furthermore, a substrate affinity switch from CTP to ATP is fulfilled with high specificity and the reaction is precisely terminated after addition of the terminal ATP. In some bacteria, the CCA-adding activity is divided into two enzymes: a CC- and an A-adding enzyme. This diversity that was long only assigned to Bacteria. However, the growing number of eukaryotic genomes allowed for deep bioinformatic investigation, revealing several eukaryotic organisms with an unusual amount of tRNA nucleotidyltransferase genes. In the present work, the function of several tRNA nucleotidyltransferases found in the genome of certain fungi, amoeba and choanoflagellates was investigated. For the tRNA nucleotidyltrans-ferases detected in Salpingoeca rosetta and Schizosaccharomyces pombe, a divided activity similar to bacterial CC- and A-adding enzymes could be observed. Additionally, in the amoeba Dictyostelium discoideum two bona fide CCA-adding enzymes were found, which are inversely regulated during the developmental cycle. In the amoeba Acanthamoeba castellanii, four different tRNA nucleotidyltransferases with different activities, localization and evolutionary origin were identified. Moreover, a method for the precise analysis of mature tRNAs by high-throughput sequencing was established as well. This method includes the specific ligation of a hairpin adapter molecule, which complementarily and highly efficiently binds to tRNAs with a 3’-CCA end resulting in a very specific preparation of tRNAs for high-throughput sequencing. It also allows for analysis of some modified bases usually found in tRNAs, which was used to analyze the alteration of certain tRNA modifications during the developmental cycle of D. discoideum.:Erklärung der Selbstständigkeit II List of Abbreviations V Bibliografische Darstellung VII Zusammenfassung 1 Summary 6 Chapter I 11 1.1. Transfer RNAs 12 1.1.1. Structure and maturation of transfer ribonucleic acids (tRNAs) 12 1.1.2. tRNAs as regulatory molecules and their role in diseases 13 1.1.3. Sequencing of tRNAs – a special challenge 14 1.1.4. The 3’-CCA end of tRNAs 15 1.2. tRNA nucleotidyltransferases 16 1.2.1. Classification and biological roles 16 1.2.2. Class II tRNA nucleotidyltransferases 18 1.2.3. Enzymes with split activity – bacterial CC- and A-adding enzymes 19 1.2.4. Two types of eukaryotic tRNA nucleotidyltransferases 21 1.2.5. Distribution of eukaryotic organisms with multiple tRNA nucleotidyltransferase genes 22 1.3. Aim of the work 23 1.4. References 25 Chapter II 33 Chapter III 44 Chapter IV 75 Chapter V 100 Chapter VI 119 Publications and Presentations IX Author Contribution Statement XI Danksagung XVI

Humans invest a substantial amount of time in the creation of artworks. For generations, humans around the world have learned and shared their knowledge and skills on artistic traditions. Albeit large experimental settings or online databases have brought considerable insights on the evolutionary role and trajectory of art, why humans invest in art, what information artworks carry and how art functions within the community still remain elusive. To address these unresolved questions, this present thesis integrates ethnographic accounts with data governance and statistical approaches to systematically investigate a large corpus of art. This thesis specifically focuses on a large corpus of Tamil kolam art from South India to provide an exemplary case study of artistic traditions. The foundation for the projects presented in this thesis was the design and construction of a robust data infrastructure that enabled the synthesis of raw data from various sources into one database for systematic analyses. The data infrastructure on the kolam artistic system enabled the development of complex statistical methods to explore the substantial investments and information complexity in art. In the first chapter, I examine artists’ strategic decisions in the creation of kolam art and how they strive to optimize the complexity of their artworks under constraints using evolutionary signaling theory and theoretically guided statistical methods. Results revealed that artists strive to maintain a stable and invariant complexity measured as Shannon information entropy, regardless of the size of the artwork. In order to achieve an optimal artistic complexity “sweet spot”, artists trade-off two standard measures of biological diversity in ecology: evenness and richness. Additionally, results showed that although kolam art arises in a highly stratified and multi-ethnic society, artistic complexity is strategically optimized across the population and not constrained by group boundaries. Instead, the trade-off can most likely be explained by aesthetic preferences or cognitive limitations. While artistic complexity in kolam art can be strategically optimized across the population, distinct styles and patterns can still be employed by artists. Thus, in the second chapter, I focus on how artistic styles in kolam art covary along cultural boundaries. I employ a novel statistical method to measure the mapping between styles onto group boundaries on a large corpus of kolam art by decomposing the system into sequential drawing decisions. In line with Chapter 1, results demonstrate limited group-level variation. Distinct styles or patterns in kolam art can only be weakly mapped to caste boundaries, neighborhoods or previous migration. Both chapters strongly suggest that kolam art is primarily a sphere where artists differentiate themselves from others by displaying their unique skill set and knowledge. Thus, variability in kolam art is largely dominated by individual-level variation and not reflective of group boundaries or narrow socialization channels. This thesis contributes to an emergent understanding of how artists conceptualize what they are doing and how art functions within the community. Taken together, this thesis serves as an example approach that demonstrates an optimized workflow and novel approaches for the evolutionary study of a large corpus of artistic traditions.

Durch die vorliegende Arbeit wurde gezeigt, dass Rhodobacter sphaeroides das Potenzial besitzt, umweltverträglich photoheterotroph Wasserstoff als alternativer, erneuerbarer Energieträger zu erzeugen. Aus genomischen und transkriptomischen Erkenntnissen konnten Rückschlüsse auf Ansatzpunkte für weitere Optimierungen getroffen werden. Durch ein neues Minimalmedium, welches zukünftig sogar einen Beitrag zur Abfallbeseitigung leisten kann, wurde ein wichtiger Schritt hinsichtlich der industriellen Anwendbarkeit von R. sphaeroides für die biologische Wasserstoffproduktion gemacht.:Danksagung Datenverfügbarkeit Inhaltsverzeichnis Abbildungsverzeichnis Tabellenverzeichnis Abkürzungsverzeichnis 1. Einleitung 1.1 Wasserstoff 1.1.1 Wasserstoff als Energieträger 1.1.2 Herstellung von Wasserstoff 1.1.2.1 Konventionelle Wasserstoffproduktion 1.1.2.2 Biologische Wasserstoffproduktion 1.1.2.3 Biologische Wasserstoffproduktion aus Abfällen 1.2 Photosynthetische Bakterien 1.2.1 Rhodobacter sphaeroides im Kontext der biologischen Wasserstoffproduktion 1.2.2 An der Wasserstoffproduktion beteiligte Enzyme 1.3 Third Generation-Sequencing Technologien 2. Zielstellung 3. Material 3.1 Chemikalien 3.2 Medien und Pufferlösungen 3.2.1 Van Niel´s Yeast Medium 3.2.2 Medium nach Krujatz et al. (2014) 3.2.3 RÄ-Medium nach Mougiakos et al. (2019) 3.2.4 PY (Peptone Yeast) Agarmedium 3.2.5 2x YT Medium 3.2.6 LB Medium 3.2.7 GYCC Medium 3.2.8 SOB Medium 3.2.9 SOC Medium 3.2.10 Pufferlösungen 3.3 Mikroorganismen 3.4 Molekularbiologische Reagenzien und Primer 3.5 Plasmide 3.5.1 pCas9 3.5.2 pRKPOL2 3.5.3 pSUPPOL2Sca 3.5.4 pBBRBB-Ppuf843-1200-DsRed 3.5.5 pBBR_cas9_NT 3.6 Geräte 4. Methoden 4.1 Rhodobacter sphaeroides Dauerkultur in Van Niel´s Yeast Medium 112 (ohne Wasserstoffproduktion) 4.2 Rhodobacter sphaeroides Batch-Kultivierung 4.2.1 Kultivierung in Medium nach Krujatz et al. (2014); Vollmedium mit Wasserstoffproduktion 4.2.2 Kultivierung in Fruchtsaftmedium 4.3 Rhodobacter sphaeroides Kultivierung mit kontinuierlicher Aufzeichnung von Temperatur, pH, optischer Dichte, Wasserstoffproduktion und Gasanalyse 4.4 Zellernte 4.5 Nukleinsäureextraktion mit dem MasterPureTM Complete RNA and DNA Purification Kit 4.6 DNase-Abbau 4.7 RNase-Abbau 4.8 Qualitätskontrolle der RNA und DNA mit dem Agilent 2100 Bioanalyzer 4.9 Reverse Transkription und Probenaufreinigung 4.10 qRT-Polymerasekettenreaktion 4.11 Etablierung der CRISPR-Cas9- Methodik bei Rhodobacter sphaeroides – Gen-Knockout der Hydrogenase Untereinheit hupL mit CRISPR-Cas9 4.11.1 Anzucht der Escherichia coli Stämme mit und ohne Plasmid 4.11.2 Plasmid Extraktion mit GeneJET Plasmid Miniprep Kit (#K0502, Thermo Scientific) 4.11.3 Restriktionsverdau zur Vektorlinearisierung 4.11.4 Design der guideRNA 4.11.5 Phosphorylierung der guideRNA 4.11.6 Ligation der guideRNA in pCas9 4.11.7 Transformation pCas9_hupL1/hupL2 in Escherichia coli JM109 durch chemische Kompetenz 4.11.8 Colony-PCR zum Insertnachweis hupL1&2 in pCas9 mit GoTaq® G2 Green Master Mix (Promega) 4.11.9 Konstruktion weiterer Vektoren mit CRISPR-Cas9 Maschinerie aus pCas9_hupL1/2 4.12 Genomeditierung in Rhodobacter sphaeroides 4.12.1 Transformation durch chemische Kompetenz mit PEG-Methode 4.12.2 Transformation durch chemische Kompetenz nach Hanahan et al. (1991) 4.12.3 Konjugation mit Escherichia coli S17-1 4.12.4 Elektroporation 4.12.5 Bioballistische Genomeditierung mit PDS-1000/He Particle Delivers System (BIORAD) 4.12.6 Konjugation mit Escherichia coli S17-1 nach Mougiakos et al. (2019) 65 4.13 Probenvorbereitung für Sequenzierungen 4.13.1 Illumina MiSeq (Genomsequenzierung) 4.13.2 MinION (Genomsequenzierung) 4.13.3 Illumina HiSeq (Transkriptomsequenzierung) 4.14 Bioinformatische Methoden 4.14.1 Genomsequenzierung (Re-Sequenzierung) 4.14.2 Transkriptom-Datenanalyse 5. Ergebnisse und Diskussion 5.1 Schrittweise Reduktion des Vollmediums nach Krujatz et al. (2014) zum Fruchtsaft-Minimalmedium 5.2 Untersuchung der Wasserstoffproduktion in Fruchtsaft-Minimalmedium 5.3 Kontinuierliche Aufzeichnung von Prozessdaten im 1,2 L Bioreaktor 5.3.1 Vergleich der Reaktorläufe in Vollmedium nach Krujatz et al. (2014), Trauben- und Ananas-Minimalmedium der Stämme DSM 158 und SubH2 5.3.2 Prozessgasanalyse 5.4 Analyse des Genoms 5.4.1 Multiples Sequenzalignment der kompletten genomischen Assemblies von Rhodobacter sphaeroides 5.4.2 MiSeq-Sequenzierung des Stammes Rhodobacter sphaeroides 2.4.1. SubH2 5.4.2.1 Bioinformatische Funktionsanalyse von SNPs 5.4.2.2 SNP-Analyse mittels Homology-Modeling 5.4.3 Genomische Architekturanalyse mittels MinION Sequenzierung der Rhodobacter sphaeroides Stämme DSM 158 und 2.4.1. SubH2 5.4.4 Vergleich der MiSeq- und MinION Genomanalysen 5.5 Analyse des Transkriptoms 5.6 Analyse der Genexpression mit qRT-PCR im Vergleich mit der Wasserstoffproduktion 5.7 CRISPR-Cas9 zum Plasmid-basierten hupL Knock-out 5.7.1 Erstellung der Plasmide pCas9_hupL1 und pCas9_hupL2 5.7.2 PEG-basierte Transformation nach Fornari et al. (1982) 5.7.3 Transformation mittels Elektroporation 5.7.4 Erstellung weiterer Vektoren mit CRISPR-Cas9_Maschinerie aus pCas9_hupL1&2 5.7.5 Transformation mittels Konjugation I 5.7.6 Bioballistische Transformation 5.7.7 Problembehandlung zur Transformation 5.7.8 Transformation mittels Konjugation II 6 Zusammenfassung 7 Ausblick 8 Summary Literaturverzeichnis Anhangsverzeichnis Anhang Versicherung

Embryogenesis is one of the most delicate biological processes which requires precise control in various levels, including molecular distribution and gene expression, cellular orientation and specification, and tissue dynamics giving rise to proper morphology. The diverse animal morphology can be resulted from the difference during early embryonic cleavages. Spiral cleavage is a conserved embryonic patterning strategy used in the majority of the animal clade Spiralia. The specific cell positioning during cell division and quadrant-based clonal domain formation make the embryos with the blastomeres orientated in a spiral manner when viewing from the animal pole. Although spiral cleavage is conserved in many phyla, the detailed cellular, molecular and biophysical mechanisms for this left-right symmetry breaking event remain unclear. Here I studied the early development of the prototypic annelid spiral-cleaver Platynereis dumerilii, which performs two unequal embryonic cleavages followed by the first dextral spiral cleavages, and compared the mechanisms to other spiralians or to other cleavage types. First, I described the morphology of each cell cycle from the zygote until 64-cell stage by imaging the fluorescently labeled fixed embryos. Second, with mRNA injection, whole-embryo live-imaging with Selective Plane Illumination Microscopy (SPIM), and in silico cell tracking, I monitored these cleavages in 4-D, constructed the early cell lineages, and revealed the subtle asynchrony of the four quartets. Third, together with the spindle inclination angle measurement, I discovered the leading role of the D macromere during P. dumerilii spiral cleavage. I also confirmed that the dextral micromere orientation is neither affected by the eggshell nor the presence of all the neighbor macromeres, suggesting that this cellular property may be achieved by cell autonomous molecular mechanisms. In order to quantify the candidate cytoskeletal dynamics during spiral cleavage, I optimized the construction of the injected mRNAs and the injection protocol to achieve the highest translational level of the fluorescent protein within a given developmental time. Beside mRNA injection, I also established a protein expression and injection protocol for P. dumerilii protein injection in order to visualize the target gene as early as possible. Both techniques didn’t dramatically influence embryogenesis and allow for quantification of the protein dynamics. With these strategies, I discovered and measured the chiral counter rotational flow of cortical actomyosin in each spiral cleavage and revealed that it’s present in the first two spiral cleavages, especially of the macromeres. The biophysical force generated by actomyosin contributes in the cell deformation and spindle inclination, resulting in proper dextral micromere positioning, during the first spiral cleavage, confirmed by the chemical treatment to the P. dumerilii embryos. The asymmetric actomyosin distribution, nuclei migration, and the change of the cell axes during cytokinesis in the macromeres also suggests that the macromeres may play critical roles to lead spiral cleavage. This work is built on the knowledge of the spiral cleavage machinery and has extended it in multiple dimensions. The detailed phase-by-phase description of each cleavage increases the information of P. dumerilii embryogenesis. The established labeling and imaging techniques in this thesis are the important basis for investigation and comparisons of different spiralian development in the future. More broadly, the discovery of actomyosin dynamics shows conservation to the left-right symmetry breaking events of the animals which does not belong to Spiralia. These together bring insights to a global evolutionary speculation: a conserved mechanical force generation pathway, tuned by the upstream molecular signals, may be the key of the miscellaneous cleavage types, resulting in the astonishing variety of embryo patterning.

In der vorliegenden Arbeit wurde erstmalig die in unter anderen in Mitteleuropa heimische Pflanze Dipsacus sylvestris HUDS. in einer Arbeit gleichzeitig phytochemisch-analytisch und pharmakologisch untersucht. Zur sicheren Identifizierung der Pflanze wurden dünnschicht- und kapillarchromato-graphische Methoden entwickelt und geeignete Markersubstanzen identifiziert. Dabei konnte eine Stufen-DC etabliert werden, die ein breites Fingerprintchromatogramm über das polare und apolare Inhaltsstoffspektrum auf einer DC-Folie ermöglicht. Mithilfe von CZE und MEKC konnten instru-mentelle Methoden entwickelt werden, die sowohl eine Pflanzen-Identifizierung, als auch im Falle der MEKC eine quantitative Erfassung ausgewählter iridoider und phenolischer Markersubstanzen zulassen. Dabei konnten Kaffee-, Chlorogensäure, Cantleyosid und Loganin quantifiziert werden. Die Methode wurde auch auf Dipsacus asperoides CHENG übertragen. Um analytische Markersubstanzen und Testsubstanzen für sich anschließende mikrobiologische Untersuchungen an Borrelia burgdorferi s.s. zu erhalten, wurden die Iridoide Loganin und Cantleyosid, das Lignan Prinsepiol und das Triterpen Ursolsäure aus D. sylvestris isoliert. Dazu wurden säulen- und planarchromatographische Methoden angewandt. Mittels NMR- und ESI-MS-Messungen wurden die erhaltenen Substanzen identifiziert. Neben den phytochemischen Untersuchungen wurden Extrakte und isolierte Reinstoffe aus D. sylv. in vitro an mediumsadaptierten B. burgdorferi s.s. auf wachstumshemmende Effekte hin untersucht. Vor allem das Lignan Prinsepiol, das erstmals aus D. sylvestris isoliert werden konnte, zeigte signifikante wachstumshemmende Effekte (0,2 mg/ml). Daneben wurden im Modell auch Ladanum und Manoyloxide sowie Carvacrol aus Cistus creticus eingesetzt. Ladanum (2,0 mg/ml), Carvacrol (0,2 und 0,05 mg/ml) und ent-13-epi-Manoyloxid (0,2 mg/ml) waren hier in vitro signifikant aktiv, während stereoisomere Manoyloxide kaum Effekte zeigten. Mit der Arbeit wurden interessante Grundlagen geschaffen, die Ausgangspunkt für weitere Forschungen sein können. So könnten sich z.B. Studien zur Toxizität, Metabolisierung und Bioverfüg-barkeit der aktiven Substanzen anschließen.:EINLEITUNG 1 Einführung in die Aufgabenstellung 2 Wilde Karde 3 Graubehaarte Zistrose 4 Borrelia burgdorferi 5 Ziele der Arbeit MATERIAL UND METHODEN 6 Verwendete Materialien 7 Methoden ERGEBNISSE 8 Ergebnisse DISKUSSION 9 Diskussion ZUSAMMENFASSUNG UND THESEN 10 Zusammenfassung und Thesen 11 Summary and theses ANHANG 12 GC-MS-Chromatogramme und Massenspektren 13 CE-Daten, Spektren und Elektropherogramme 14 NMR-Spektren 15 Zähldaten der Bbss-Bestimmungen 16 Weitere Diagramme der Bbss-Bestimmungen (Wiederholungsexperimente) VERZEICHNISSE 17 Literaturverzeichnis 18 Abbildungsverzeichnis 19 Tabellenverzeichnis 20 Formelverzeichnis 21 Abkürzungsverzeichnis WEITERE INFORMATIONEN 22 Lebenslauf, Publikationen 23 Erklärung über die eigenständige Abfassung der Arbeit / In the present study, the plant Dipsacus sylvestris HUDS., which is native in Central Europe among others, was examined for the first time both phytochemically and pharmacologically. Thin-layer and capillary chromatographic methods have been developed and suitable marker substances have been identified for the reliable identification of the plant. A stepwise developed TLC was established, which enables a broad fingerprint chromatogram over the polar and apolar ingredient spectrum on one single TLC plate. With the help of CZE and MEKC, instrumental methods have been developed that allow both plant identification and, in the case of MEKC, quantitative detection of selected iridoid and phenolic marker substances. Caffeic acid, chlorogenic acid, cantleyoside, and loganin could be quantified. The method was also transferred to Dipsacus asperoides CHENG. In order to obtain analytical marker substances and test substances for subsequent microbiological investigations on Borrelia burgdorferi s.s., the iridoids loganin and cantleyoside, the lignan prinsepiol and the triterpenoid ursolic acid were isolated from D. sylvestris. Column and planar chromatographic methods were used for this purpose. The isolated substances were identified by NMR and ESI-MS measurements. In addition to phytochemical investigations, extracts and isolated pure substances from D. sylv. were tested in vitro for growth-inhibiting effects on medium-adapted B. burgdorferi s.s. Especially the lignan prinsepiol, which could be isolated from D. sylvestris for the first time, showed significant growth-inhibiting effects (0.2 mg/ml). Ladanum and various manoyl oxides as well as carvacrol from Cistus creticus were also used in the model. Ladanum (2.0 mg/ml), carvacrol (0.2 and 0.05 mg/ml) and ent-13-epi manoyl oxide (0.2 mg/ml) were significantly active in vitro, while stereoisomeric manoyl oxides showed hardly any effects. The results obtained in this work set the stage for further research including e.g. studies on toxicity, metabolism, and bioavailability of active substances.:EINLEITUNG 1 Einführung in die Aufgabenstellung 2 Wilde Karde 3 Graubehaarte Zistrose 4 Borrelia burgdorferi 5 Ziele der Arbeit MATERIAL UND METHODEN 6 Verwendete Materialien 7 Methoden ERGEBNISSE 8 Ergebnisse DISKUSSION 9 Diskussion ZUSAMMENFASSUNG UND THESEN 10 Zusammenfassung und Thesen 11 Summary and theses ANHANG 12 GC-MS-Chromatogramme und Massenspektren 13 CE-Daten, Spektren und Elektropherogramme 14 NMR-Spektren 15 Zähldaten der Bbss-Bestimmungen 16 Weitere Diagramme der Bbss-Bestimmungen (Wiederholungsexperimente) VERZEICHNISSE 17 Literaturverzeichnis 18 Abbildungsverzeichnis 19 Tabellenverzeichnis 20 Formelverzeichnis 21 Abkürzungsverzeichnis WEITERE INFORMATIONEN 22 Lebenslauf, Publikationen 23 Erklärung über die eigenständige Abfassung der Arbeit

Sediment and nutrient retention are important ecosystem functions floodplain meadows fulfil. While it is known that the inundated floodplain vegetation purifies the water during floods, little is known about the processes behind. I investigated the effect of the vegetation structure on sedimentation at three hierarchical scales, leaf, patch, and floodplain scale and used two approaches, experiments and an in situ field study. In the leaf experiment (study 1) I inundated single leaves into sediment rich water. The results showed that leaf pubescence increased sedimentation on leaf surfaces and that for leaves without hairs, the sedimentation increased with decreasing leaf area. In the flume experiment (study 2) I investigated the effects of community characteristics of vegetation patches regarding their capacity to capture sediment. I manipulated the leaf pubescence, the community density, the community height and the structural diversity (high-high vs high-low growing species) of the patches. The results show that all four investigated community characteristics increased the sediment retention. In the second flume experiment (study 3), I investigated the effect of species richness of vegetation patches on sediment retention. The results showed the importance of the vegetation biomass and identity effects of single species, but no clear effect of species richness. For the in situ field measurements (study 4), I measured sedimentation during a real flood event along the Mulde River in Germany. With sediment traps and biomass harvests I quantified the sedimentation underneath as well as on the vegetation. The results showed that besides the vegetation biomass, the topographical parameter ‘hydrological distance’ (pathway of lowest elevation the water travels to the site) is important for sediment and especially nutrient retention. Even though sediment retention is highest close by the river, sedimentation is still reasonably high far insight the floodplain and especially nutrient retention (C, N and P) increase with hydrological distance. From the sum of results I can derive four management strategies for floodplains to increase the sediment retention. First, reduced mowing for more standing biomass during flood season, wherefore trade-offs with other ecosystem functions need to be evaluated carefully. Second, promotion of structural diversity, possible via species diversity. Third, promotion of species with characteristics that increase sediment, such as pubescent leaves. Forth, preserving or recreating topographic complexity in the floodplain. Overall, I showed that the specific structures of herbaceous vegetation are highly beneficial for sediment and nutrient retention on floodplains.:Table of contents 1. General introduction 6 1.1 The Mulde River and the “Wilde Mulde” project 7 1.2 Sediment retention on floodplains 8 1.3 Vegetation causes fine sedimentation 11 1.4 Structural characteristics 12 1.4.1 Structural identity of species 13 1.4.2 Structural identity of communities 14 1.4.3 Structural diversity of communities 15 1.5 Links between studies 17 2. Methodological features 19 2.1 Study area “Wilde Mulde” 19 2.2 Leaf roughness measurement 22 2.3 Experimental set up of the flume experiment 24 3. Original contributions 26 3.1 Paper 1 - Leaf area and pubescence drive sedimentation on leaves surfaces during flooding 26 3.2 Paper 2 – Plant structural diversity alters sediment retention on and underneath herbaceous vegetation in a flume experiment 44 3.3 Paper 3 – Effects of plant species identity overrides diversity effects in explaining sedimentation within vegetation in a flume experiment 65 3.4 Paper 4 – Vegetation characteristics control sediment and nutrient retention on but not underneath vegetation in floodplain meadows 77 4. Discussion 107 4.1 Mechanistic parallels among scales 109 4.2 Effects of species diversity in relation to species identity 112 4.3 Transferability and its limitations 113 4.4 The ecosystem function of sediment retention 114 4.4.1 Floodplain management for sediment retention 115 4.4.2 Sediment retention in the context of other ecosystem functions 117 4.4.3 Floodplain management for sediment retention along the Lower Mulde River 119 5. Outlook 122 5.1 Leaf roughness 122 5.2 Diversity experiment 123 5.3 Approaches for new management strategies 124 5.4 Extrapolation with remote sensing 125 5.5 Sediment budget 126 6. Conclusion 128 7. References 130 8. Summary 143 9. Zusammenfassung 149 Acknowledgements 155 Author contribution statement 156 Curriculum vitae 164 List of publications 166 Selbstständigkeitserklärung 169

Tight barriers are crucial for animals. Insect respiratory cells establish barriers through their extracellular matrices. These chitinous-matrices must be soft and flexible to provide ventilation, but also tight enough to allow oxygen flow and protection against dehydration, infections, and environmental stresses. However, genes that control soft, flexible chitin-matrices are poorly known. We investigated the genes of the chitinolytic glycosylhydrolase-family 18 in the tracheal system of Drosophila melanogaster. Our findings show that five chitinases and three chitinase-like genes organize the tracheal chitin-cuticles. Most of the chitinases degrade chitin from airway lumina to enable oxygen delivery. They further improve chitin-cuticles to enhance tube stability and integrity against stresses. Unexpectedly, some chitinases also support chitin assembly to expand the tube lumen properly. Moreover, Chitinase2 plays a decisive role in the chitin-cuticle formation that establishes taenidial folds to support tube stability. Chitinase2 is apically enriched on the surface of tracheal cells, where it controls the chitin-matrix architecture independently of other known cuticular proteins or chitinases. We suppose that the principle mechanisms of chitin-cuticle assembly and degradation require a set of critical glycosylhydrolases for flexible and not-flexible cuticles. The same glycosylhydrolases support thick laminar cuticle formation and are evolutionarily conserved among arthropods.