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- ItemLaccase‐Catalyzed Derivatization of Aminoglycoside Antibiotics and Glucosamine(Basel : MDPI, 2022) Mikolasch, Annett; Lindequist, Ulrike; Witt, Sabine; Hahn, VeronikaThe increasing demand for new and effective antibiotics requires intelligent strategies to obtain a wide range of potential candidates. Laccase‐catalyzed reactions have been successfully applied to synthesize new β‐lactam antibiotics and other antibiotics. In this work, laccases from three different origins were used to produce new aminoglycoside antibiotics. Kanamycin, tobramycin and gentamicin were coupled with the laccase substrate 2,5‐dihydroxy‐N‐(2‐hydroxyethyl)‐benzamide. The products were isolated, structurally characterized and tested in vitro for antibacterial activity against various strains of Staphylococci, including multidrug‐resistant strains. The cytotoxicity of these products was tested using FL cells. The coupling products showed comparable and, in some cases, better antibacterial activity than the parent antibiotics in the agar diffusion assay, and they were not cytotoxic. The products protected mice against infection with Staphylococcus aureus, which was lethal to the control animals. The results underline the great potential of laccases in obtaining new biologically active compounds, in this case new antibiotic candidates from the class of aminoglycosides.
- ItemNon-thermal plasma treatment induces MAPK signaling in human monocytes(Berlin : de Gruyter, 2014) Bundscherer, Lena; Nagel, Stefanie; Hasse, Sybille; Tresp, Helena; Wende, Kristian; Walther, Reinhard; Reuter, Stephan; Weltmann, Klaus-Dieter; Masur, Kai; Lindequist, UlrikeThe application of non-thermal atmospheric pressure plasma raises a hope for the new wound healing strategies. Next to its antibacterial effect it is known to stimulate skin cells. However, monocytes are also needed for the complex process of a wound healing. This study investigates the impact of plasma on the intracellular signaling events in the primary human monocytes. The proliferative MEK-ERK (MAPK/ERK kinase-extracellular signal-regulated kinase) pathway was activated by short plasma treatment times. In contrast, an induction of the apoptotic JNK (c-Jun N-terminal kinase) cascade as well as activation of caspase 3 were observed after long plasma exposure. These findings indicate that monocytes can be differentially stimulated by plasma treatment and may contribute to the proper wound recovery.
- ItemPlasmatis : Plasma plus Zelle ; executive summary(Hannover : Technische Informationsbibliothek (TIB), 2008) Weltmann, Klaus-Dieter; Lindequist, Ulrike; Kramer, Axel[no abstract available]