TY - JOUR A1 - Hegmann, Joachim A1 - Christl, Manfred A1 - Peters, Karl A1 - Peters, Eva-Maria A1 - Schnering, Hans Georg von T1 - Die Reaktionskaskade von 6-Oxo-5-phenyl-1,3,4-oxadiazin-2-carbonsäure-methylester und 1,3-Butadienen zu konjugierten und nichtkonjugierten Cyclopentenonen N2 - Fünfgliedrige Carbocyclen sind Bauelemente zahlreicher NaturstofTe und daher attraktive Syntheseziele. Da bisher kein Syntheseverfahren mit großer Anwendungsbreite bekannt ist, sind neue Methoden willkommen. Wir berichten hier über Umsetzungen des Titelheterocyclus 1 mit l,3-Butadienen 1; diese Reaktionen, obwohl vielstufig, liefern im Eintopfverfahren konjugierte und nichtkonjugierte Cyclopentenone und gestatten auch die Fünfringanellierung. KW - Organische Chemie Y1 - 1988 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-58421 ER - TY - JOUR A1 - Christl, Manfred A1 - Lang, Reinhard A1 - Herzog, Clemens A1 - Stangl, Roland A1 - Peters, Karl A1 - Peters, Eva-Maria A1 - Schnering, Hans Georg von T1 - Reaktion von Homobenzvalen mit Tetracyanethylen : Bildung eines Tetracyandihydrobarbaralan- und eines Tetracyancyclopropan-Derivats N2 - In den Reaktionen von Tetracyanethylen (TCNE) und 5,6-Dichlor-2,3-dicyan-p-benzochinon mit Benzvalen haben wir kürzlich die ersten Beispiele für die lange gesuchte einstufige 1,4-Cycloaddition eines Alkens an ein Vinylcyclopropan gcfunden(I~J. Sie ist als [(.,2.+.2s)+ 112J-Prozeß der Dicls-Alder-Addition nahe verwandtllbl. Allerdings entsteht das betreffende TCNE-Addukt, ein Dihydrosemibullvalen-Derivat, nur in einer Ausbeute von wenigen Prozent. Die Hauptprodukte gehen aus einer Zwitterionischen Zwischenstufe hervor, die durch Anlagerung von TCNE an die Benzvalen-n-Bindung resultiert. Professor Rolf Huisgen zum 65. Geburtstag gewidmet KW - Chemie KW - Homobenzvalene Y1 - 1985 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-31839 ER - TY - JOUR A1 - Hegmann, Joachim A1 - Christl, Manfred A1 - Peters, Karl A1 - Peters, Eva-Maria A1 - Schnering, Hans Georg T1 - Conjugated and Nonconjugated Cyclopentenones by a Reaction Cascade from Methyl 6-0xo-5-phenyl-1,3,4-oxadiazine-2-carboxylate and 1,3-Butadienes N2 - No abstract available Y1 - 1988 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-30207 ER - TY - JOUR A1 - Schleuning, Matthias A1 - Farwig, Nina A1 - Peters, Marcell K. A1 - Bergsdorf, Thomas A1 - Bleher, Bärbel A1 - Brandl, Roland A1 - Dalitz, Helmut A1 - Fischer, Georg A1 - Freund, Wolfram A1 - Gikungu, Mary W. A1 - Hagen, Melanie A1 - Garcia, Francisco Hita A1 - Kagezi, Godfrey H. A1 - Kaib, Manfred A1 - Kraemer, Manfred A1 - Lung, Tobias A1 - Naumann, Clas M. A1 - Schaab, Gertrud A1 - Templin, Mathias A1 - Uster, Dana A1 - Wägele, J. Wolfgang A1 - Böhning-Gaese, Katrin T1 - Forest Fragmentation and Selective Logging Have Inconsistent Effects on Multiple Animal-Mediated Ecosystem Processes in a Tropical Forest JF - PLoS ONE N2 - Forest fragmentation and selective logging are two main drivers of global environmental change and modify biodiversity and environmental conditions in many tropical forests. The consequences of these changes for the functioning of tropical forest ecosystems have rarely been explored in a comprehensive approach. In a Kenyan rainforest, we studied six animal-mediated ecosystem processes and recorded species richness and community composition of all animal taxa involved in these processes. We used linear models and a formal meta-analysis to test whether forest fragmentation and selective logging affected ecosystem processes and biodiversity and used structural equation models to disentangle direct from biodiversity-related indirect effects of human disturbance on multiple ecosystem processes. Fragmentation increased decomposition and reduced antbird predation, while selective logging consistently increased pollination, seed dispersal and army-ant raiding. Fragmentation modified species richness or community composition of five taxa, whereas selective logging did not affect any component of biodiversity. Changes in the abundance of functionally important species were related to lower predation by antbirds and higher decomposition rates in small forest fragments. The positive effects of selective logging on bee pollination, bird seed dispersal and army-ant raiding were direct, i.e. not related to changes in biodiversity, and were probably due to behavioural changes of these highly mobile animal taxa. We conclude that animal-mediated ecosystem processes respond in distinct ways to different types of human disturbance in Kakamega Forest. Our findings suggest that forest fragmentation affects ecosystem processes indirectly by changes in biodiversity, whereas selective logging influences processes directly by modifying local environmental conditions and resource distributions. The positive to neutral effects of selective logging on ecosystem processes show that the functionality of tropical forests can be maintained in moderately disturbed forest fragments. Conservation concepts for tropical forests should thus include not only remaining pristine forests but also functionally viable forest remnants. KW - Ant-following birds KW - Land-use change KW - Habitat fragmentation KW - Rain-forest KW - Functional diversity KW - Plantation forests KW - Amazonian forest KW - Prunus-africana KW - Seed dispersal KW - Logged forests Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-140093 VL - 6 IS - 11 ER - TY - JOUR A1 - Bringmann, Gerhard A1 - Hartung, Thomas A1 - Goebel, Lothar A1 - Schupp, Olaf A1 - Ewers, Christian L. J. A1 - Schoener, Bernd A1 - Zagst, Rainer A1 - Peters, Karl A1 - Von Schnering, Hans Georg A1 - Burschka, Christian T1 - Novel concepts in directed biaryl synthesis, IX: Synthesis and structure of benzonaphthopyranones, useful bridged model precursors for stereoselective biaryl syntheses N2 - A practicable two-step procedure for the preparation of a series of lactone-type bridged biaryls 7 as favorable substrates for subsequent atropisomer-selective ring-opening reactions is described. Due to the efficiency of the coupling step, which tolerates even a telt·butyl group next to the biaryl axis and avoids problems of regioselectivity, a variety of differently substituted representatives is prepared. These cover a broad range of steric hindrance and thus molecular distortion. The structures are investigated mainly by NMR spectroscopy and X-ray diffraction, showing the lactones 7 to be helically distorted, depending on the size of the residues R. KW - Chemie Y1 - 1992 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-46635 ER - TY - JOUR A1 - Reimer, Georg A1 - Scheer, Ulrich A1 - Peters, Jan-Michael A1 - Tan, Eng M. T1 - Immunolocalization and partial characterization of a nucleolar autoantigen (PM-Scl) associated with polymyositis / scleroderma overlap syndromes. N2 - Precipitating anti-PM-Sel antibodies are present in sera from patients with polymyositis. scleroderma. and polymyositis/scleroderma overlap syndromes. By indirect immunofluorescence microscopy. anti-PM-Scl antibodies stained the nucleolus in cells of different tissues and species. suggesting that the antigen is highly conserved. By electron microscopy, anti-PM-Scl antibodies reacted primarily with the granular component of the nuc1eolus. Drugs that inhibit rRNA synthesis had a marked effect on the expression of PM-Scl antigen. In actinomycin D-treated cells, immunofluorescence staining by anti-PM-Scl was signüicantly reduced with residual staining restricted to the granular regions of nuc1eoli. Treatment with 5,6-dichloro-beta-D- ribofuranosylbenzimidazole (DRB) also selectively reduced nuc1eolar staining. On a molecular level, anti-PM-Sel antibodies precipitated 11 polypeptides with molecular weights (Mr) ranging from 110,000 to 20,000. The Mr 80,000 and 20.000 polypeptides were phosphorylated. Evidence suggests that the PM-Scl antigen complex may be related to a prerlbosomal particle. Y1 - 1986 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-33191 ER - TY - JOUR A1 - Tuchscherr, Lorena A1 - Bischoff, Markus A1 - Lattar, Santiago M. A1 - Noto Llana, Mariangeles A1 - Pförtner, Henrike A1 - Niemann, Silke A1 - Geraci, Jennifer A1 - Van de Vyver, Hélène A1 - Fraunholz, Martin J. A1 - Cheung, Ambrose L. A1 - Herrmann, Mathias A1 - Völker, Uwe A1 - Sordelli, Daniel O. A1 - Peters, Georg A1 - Loeffler, Bettina T1 - Sigma factor SigB is crucial to mediate Staphylococcus aureus adaptation during chronic infections JF - PLoS Pathogens N2 - Staphylococcus aureus is a major human pathogen that causes a range of infections from acute invasive to chronic and difficult-to-treat. Infection strategies associated with persisting S. aureus infections are bacterial host cell invasion and the bacterial ability to dynamically change phenotypes from the aggressive wild-type to small colony variants (SCVs), which are adapted for intracellular long-term persistence. The underlying mechanisms of the bacterial switching and adaptation mechanisms appear to be very dynamic, but are largely unknown. Here, we analyzed the role and the crosstalk of the global S. aureus regulators agr, sarA and SigB by generating single, double and triple mutants, and testing them with proteome analysis and in different in vitro and in vivo infection models. We were able to demonstrate that SigB is the crucial factor for adaptation in chronic infections. During acute infection, the bacteria require the simultaneous action of the agr and sarA loci to defend against invading immune cells by causing inflammation and cytotoxicity and to escape from phagosomes in their host cells that enable them to settle an infection at high bacterial density. To persist intracellularly the bacteria subsequently need to silence agr and sarA. Indeed agr and sarA deletion mutants expressed a much lower number of virulence factors and could persist at high numbers intracellularly. SigB plays a crucial function to promote bacterial intracellular persistence. In fact, \(\Delta\)sigB-mutants did not generate SCVs and were completely cleared by the host cells within a few days. In this study we identified SigB as an essential factor that enables the bacteria to switch from the highly aggressive phenotype that settles an acute infection to a silent SCV-phenotype that allows for long-term intracellular persistence. Consequently, the SigB-operon represents a possible target to develop preventive and therapeutic strategies against chronic and therapy-refractory infections. KW - gene regulator agr KW - endothelial cells KW - modulates virulence KW - death pathway sar locus KW - factor B KW - small-colony variants KW - alpha-toxin KW - epithelial cells KW - in vitro Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-143419 VL - 11 IS - 4 ER - TY - JOUR A1 - Bruchhagen, Christin A1 - Jarick, Marcel A1 - Mewis, Carolin A1 - Hertlein, Tobias A1 - Niemann, Silke A1 - Ohlsen, Knut A1 - Peters, Georg A1 - Planz, Oliver A1 - Ludwig, Stephan A1 - Ehrhardt, Christina T1 - Metabolic conversion of CI-1040 turns a cellular MEK-inhibitor into an antibacterial compound JF - Scientific Reports N2 - Influenza virus (IV) infections cause severe respiratory illnesses that can be complicated by bacterial super-infections. Previously, we identified the cellular Raf-MEK-ERK cascade as a promising antiviral target. Inhibitors of MEK, such as CI-1040, showed potent antiviral activity. However, it remained unclear if this inhibitor and its active form, ATR-002, might sensitize host cells to either IV or secondary bacterial infections. To address these questions, we studied the anti-pathogen activity of ATR-002 in comparison to CI-1040, particularly, its impact on Staphylococcus aureus (S. aureus), which is a major cause of IV super-infections. We analysed IV and S. aureus titres in vitro during super-infection in the presence and absence of the drugs and characterized the direct impact of ATR-002 on bacterial growth and phenotypic changes. Importantly, neither CI-1040 nor ATR-002 treatment led to increased bacterial titres during super-infection, indicating that the drug does not sensitize cells for bacterial infection. In contrast, we rather observed reduced bacterial titres in presence of ATR-002. Surprisingly, ATR-002 also led to reduced bacterial growth in suspension cultures, reduced stress- and antibiotic tolerance without resistance induction. Our data identified for the first time that a particular MEK-inhibitor metabolite exhibits direct antibacterial activity, which is likely due to interference with the bacterial PknB kinase/Stp phosphatase signalling system. KW - antimicrobials KW - pathogens Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-221648 VL - 8 ER - TY - JOUR A1 - Lenz, Dominic A1 - Pahl, Jens A1 - Hauck, Fabian A1 - Alameer, Seham A1 - Balasubramanian, Meena A1 - Baric, Ivo A1 - Boy, Nikolas A1 - Church, Joseph A. A1 - Crushell, Ellen A1 - Dick, Anke A1 - Distelmaier, Felix A1 - Gujar, Jidnyasa A1 - Indolfi, Giuseppe A1 - Lurz, Eberhard A1 - Peters, Bianca A1 - Schwerd, Tobias A1 - Serranti, Daniele A1 - Kölker, Stefan A1 - Klein, Christoph A1 - Hoffmann, Georg F. A1 - Prokisch, Holger A1 - Greil, Johann A1 - Cerwenka, Adelheid A1 - Giese, Thomas A1 - Staufner, Christian T1 - NBAS Variants Are Associated with Quantitative and Qualitative NK and B Cell Deficiency JF - Journal of Clinical Immunology N2 - Purpose Biallelic pathogenic NBAS variants manifest as a multisystem disorder with heterogeneous clinical phenotypes such as recurrent acute liver failure, growth retardation, and susceptibility to infections. This study explores how NBAS-associated disease affects cells of the innate and adaptive immune system. Methods Clinical and laboratory parameters were combined with functional multi-parametric immunophenotyping methods in fifteen NBAS-deficient patients to discover possible alterations in their immune system. Results Our study revealed reduced absolute numbers of mature CD56dim natural killer (NK) cells. Notably, the residual NK cell population in NBAS-deficient patients exerted a lower potential for activation and degranulation in response to K562 target cells, suggesting an NK cell–intrinsic role for NBAS in the release of cytotoxic granules. NBAS-deficient NK cell activation and degranulation was normalized upon pre-activation by IL-2 in vitro, suggesting that functional impairment was reversible. In addition, we observed a reduced number of naïve B cells in the peripheral blood associated with hypogammaglobulinemia. Conclusion In summary, we demonstrate that pathogenic biallelic variants in NBAS are associated with dysfunctional NK cells as well as impaired adaptive humoral immunity. KW - NBAS KW - inborn error of immunity KW - NK cell deficiency KW - B cell deficiency KW - vesicle trafficking KW - familial hemophagocytic lymphohistiocytosis Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-308362 SN - 0271-9142 SN - 1573-2592 VL - 41 IS - 8 ER -