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Item type: Item , Striving for Sustainable Organocatalysis: Design and Characterization of Silica Monolith Supports and Application of Chitosan as a Solid Catalyst(2025) Ali, UsmanSustainable organocatalysis requires heterogeneous catalytic systems that are efficient, reusable, and aligned with the principles of sustainability. This thesis explores two complementary materials aimed at achieving this balance: the rational engineering of hierarchically porous silica monolith support and the utilization of renewable chitosan biopolymers as solid catalysts. Together, these studies illustrate how rational control over material structure and intrinsic functionality can be harnessed to simultaneously enhance catalytic performance and align with environmental sustainability. In Publication 1, the focus was on the structural evolution of mesoporosity in hierarchically porous silica monoliths prepared by the Nakanishi method. The study placed particular emphasis on advanced physisorption analyses using argon (87 K) and nitrogen (77 K), complemented by hysteresis scanning, to unravel the development of the mesoporous network under varying hydrothermal treatment temperatures (HTTs). These analyses revealed a systematic expansion of mesopores (8 to 25 nm) while maintaining constant pore volume, indicating a dissolution-reprecipitation mechanism that governs mesopore formation and connectivity. The work provided fundamental insights into how hydrothermal conditions shape mesoporous network, diffusion, and accessibility, establishing design principles for tailoring monoliths for catalytic and separation applications. In Publication 2, chitosan was studied as a renewable heterogeneous organocatalyst for Knoevenagel condensations among various benzaldehydes and ethyl cyanoacetate. High yields were achieved under mild conditions, with efficient catalyst and solvent reuse across multiple cycles. Importantly, the study demonstrated that renewability alone is not enough; optimization of overall process through mild conditions, energy efficiency, and recyclability can make a genuine impact on sustainable synthesis. The approach was successfully optimized to the gram-scale synthesis of an Atorvastatin intermediate, underlining its practical relevance. Together, these publications highlight two distinct but complementary strategies: the controlled engineering of pore structures in silica monoliths for applications such as continuous-flow catalysis and the dynamic functionality of chitosan as a green catalyst. Both approaches contribute to the broader goal of developing efficient, robust, and truly sustainable organocatalytic systems.Item type: Item , Hepatozelluläre Expression von Oberflächenproteinen des Hepatitis-B-Virus führt in BALB/c-Mäusen zur Inhibition von Autophagie(2025) Imiela, Christoph SebastianAutophagie ist ein zentraler kataboler Stoffwechselweg, der den Abbau von intrazellulären Komponenten wie Proteinaggregaten und Organellen vermittelt. Intrazelluläre Erreger haben Mechanismen entwickelt, um dem Abbau durch Autophagie zu entgehen. Das Hepatitis-B-Virus (HBV) nutzt solche Schutzmechanismen und rekrutiert Autophagosomen zur Bildung seiner Virushülle. Bei chronischer Hepatitis-B-Infektion (CHB), die durch eine unzureichende Immunantwort gekennzeichnet ist, bilden sich in infizierten Hepatozyten Aggregate aus Lipiden und HBV-Oberflächenproteinen (HBsAg), bekannt als Milchglashepatozyten (GGHs). Sie sind ein typisches histologisches Merkmal der CHB. Ziel dieser Studie ist es, Zusammensetzung und Entstehung von GGHs und die Auswirkungen von HBV auf Autophagie zu analysieren. Untersucht wurden der Einfluss der antiviralen Interferonantwort, die ER-Stress-Reaktion mit nachfolgender Unfolded Protein Response (UPR) sowie der Einfluss des genetischen Hintergrundes der Mäuse (BALB/c vs. C57BL/6). Grundlage dazu bildete das von Chisari et al. etablierte In-vivo-HBsAg-Überexpressionsmodell. Die transgenen Mäuse exprimierten die HBV-Oberflächenproteine SHBs, MHBs und LHBs in der Leber. Zur Untersuchung der Typ-I-Interferonantwort diente der IRF3/7 Knockout (KO). Genetische Einflüsse wurden anhand von BALB/c- und C57BL/6-Mäusen geprüft. HBs führte unabhängig von Mausstamm und IRF3/7 KO zu ER-Stress und der UPR, welche Autophagie induzieren kann. Der Knockout von IRF3/7 blockiert erfolgreich die Typ-I-Interferonantwort. Allerdings induzierte HBs nur in BALB/c Mäusen eine Interferonantwort, die Autophagie initiieren kann. In IRF3/7 KO und C57BL/6 Mäusen blieben diese Reaktionen aus, verbunden mit massiver Aggregatbildung und GGH Entstehung. HBs hemmt in Mäusen auf BALB/c Hintergrund (BALB/c und IRF3/7 KO) den Abbau durch Blockade später Stadien von Autophagie (gestörter Flux). Dies verhindert den Abbau von HBV durch Autophagie und lässt Autophagosomen akkumulieren, die HBV zur Behüllung benötigt. Ebenfalls akkumulierten durch HBs auch Lysosomen, in denen der Abbau stattfinden würde. Dabei akkumulierten durch HBs mehr Autophagosomen in BALB/c TG als in IRF3/7 KO TG Mäusen. Das legt eine zusätzliche Induktion von Autophagie durch die Interferonantwort in BALB/c nahe. Bei intakter Interferonantwort wird die Aggregatbildung und Bildung von GGHs verhindert. Möglicherweise entsteht dieser Effekt durch eine interferonabhängige Regulation von mTORC1, einem Schlüsselregulator der Autophagieinitiation. Unsere Ergebnisse liefern neue Einblicke in die Interaktion zwischen HBV, Autophagie und der antiviralen Immunantwort und tragen zum Verständnis der Pathogenese der CHB bei.Item type: Item , Description of Cohnella rhizoplanae sp. nov., isolated from the root surface of soybean (Glycine max)(2025) Kämpfer, Peter; Glaeser, Stefanie P.; McInroy, John A.; Busse, Hans-Jürgen; Clermont, Dominique; Criscuolo, AlexisA Gram-staining-positive, aerobic bacterium, designated strain JJ-181 T, was isolated from the root surface of soybean. Based on the 16S rRNA gene sequence similarities, strain JJ-181 T was grouped into the genus Cohnella, most closely related to Cohnella hashimotonis F6_2S_P_1T (98.85%) and C. ginsengisoli GR21-5 T (98.3%). The pairwise average nucleotide identity and digital DNA-DNA hybridisation values of the JJ-181 T genome assembly against publicly available Cohnella type strain genomes were below 84% and 28%, respectively. The fatty acid profile from whole cell hydrolysates, the cell wall diaminoacid, the quinone system, the polar lipid profile, and the polyamine pattern supported the allocation of strain JJ-181 T to the genus Cohnella. In addition, the results of physiological and biochemical tests also allowed phenotypic differentiation of strain JJ-181 T from its closely-related Cohnella species. Functional analysis revealed that strain JJ-181 T has different gene clusters related to swarming motility, chemotaxis ability, and endospore and biofilm formations. The gene content also suggests the ability of strain JJ-181 T to synthesise biotin and riboflavin, as well as indole-3-acetic acid, an important phytohormone for plant growth. Based on polyphasic analyses, strain JJ-181 T can be classified as a new species of the genus Cohnella, for which we propose the name Cohnella rhizoplanae sp. nov., with strain JJ-181 T (= LMG 31678 T = CIP 112018 T = CCM 9031 T = DSM 110650 T) as the type strain.Item type: Item , A biocontrol perspective on mycoviruses in fungal pathogen management(2025) Galli, Matteo; Sede, Ana; Heinlein, Manfred; Kogel, Karl-HeinzMycoviruses, viruses that infect fungi, have been identified across nearly every fungal taxon. Despite their widespread presence, the ecological effects of mycoviruses remain poorly understood. They can influence the biology of their hosts in various ways, including altering growth, reproduction, and pathogenicity. Their ability to induce either fungal hyper- or hypovirulence and thus regulate general fungal fitness by increasing fungal aggressiveness or, conversely, in extreme cases, converting harmful fungi into beneficial ones, has attracted increasing attention in recent years as a potential means of protecting plants from fungal diseases and pests. Increasing difficulties in controlling fungal diseases, pests and weeds with synthetic chemical pesticides, exacerbated by the emergence of resistance or tolerance to certain active ingredients, and stricter regulatory requirements due to environmental and health concerns, have stimulated interest in alternative approaches. In parallel with the introduction of double-stranded (ds)RNA-based products for crop protection and the fundamental knowledge generated in this field in recent years, the potential use of mycoviruses to control pathogenic fungi appears to be within reach. This review highlights recent advances in the field and emphasizes the potential of mycoviruses as biological control agents (BCAs), with the emphasis on the utilization of mycovirus-induced fungal hypovirulence to control fungi that cause plant diseases and mycovirus-induced fungal hypervirulence to protect plants from fungal hosts such insect pests or weeds.Item type: Item , Nirenberg problem on high dimensional spheres : blow up with residual mass phenomenon(2025) Ahmedou, Mohameden; Ben Ayed, Mohamed; El Mehdi, KhalilIn this paper, we extend the analysis of the subcritical approximation of the Nirenberg problem on spheres recently conducted in Malchiodi and Mayer(J Differ Equ 268(5):2089–2124, 2020; Int Math Res Not 18:14123–14203, 2021). Specifically, we delve into the scenario where the sequence of blowing up solutions exhibits a non-zero weak limit, which necessarily constitutes a solution of the Nirenberg problem itself. Our focus lies in providing a comprehensive description of such blowing up solutions, including precise determinations of blow-up points and blow-up rates. Additionally, we compute the topological contribution of these solutions to the difference in topology between the level sets of the associated Euler-Lagrange functional. Such an analysis is intricate due to the potential degeneracy of the solutions involved. We also provide a partial converse, wherein we construct blowing up solutions when the weak limit is non-degenerate.