Identification of the amino acid labionin and its desulfurised derivative in the type-III lantibiotic LabA2 by means of GC/MS

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.A GC-MS method for the rapid and unambiguous identification of the amino acid labionin (Lab) occurring in type-III lantibiotics is presented. This method will constitute a valuable tool for the characterisation and structure elucidation of labyrinthopeptins and their differentiation from lanthionine-type lantibiotics

What makes Xanthomonas albilineans unique amongst xanthomonads?

Xanthomonas albilineans causes leaf scald, a lethal disease of sugarcane. Compared to other species of Xanthomonas, X. albilineans exhibits distinctive pathogenic mechanisms, ecology and taxonomy. Its genome, which has experienced significant erosion, has unique genomic features. It lacks two loci required for pathogenicity in other plant pathogenic species of Xanthomonas: the xanthan gum biosynthesis and the Hrp-T3SS (hypersensitive response and pathogenicity-type three secretion system) gene clusters. Instead, X. albilineans harbors in its genome an SPI-1 (Salmonella pathogenicity island-1) T3SS gene cluster usually found in animal pathogens. X. albilineans produces a potent DNA gyrase inhibitor called albicidin, which blocks chloroplast differentiation, resulting in the characteristic white foliar stripe symptoms. The antibacterial activity of albicidin also confers on X. albilineans a competitive advantage against rival bacteria during sugarcane colonization. Recent chemical studies have uncovered the unique structure of albicidin and allowed us to partially elucidate its fascinating biosynthesis apparatus, which involves an enigmatic hybrid PKS/NRPS (polyketide synthase/non-ribosomal peptide synthetase) machinery

Champacyclin, a New Cyclic Octapeptide from Streptomyces Strain C42 Isolated from the Baltic Sea

New isolates of Streptomyces champavatii were isolated from marine sediments of the Gotland Deep (Baltic Sea), from the Urania Basin (Eastern Mediterranean), and from the Kiel Bight (Baltic Sea). The isolates produced several oligopeptidic secondary metabolites, including the new octapeptide champacyclin (1a) present in all three strains. Herein, we report on the isolation, structure elucidation and determination of the absolute stereochemistry of this isoleucine/leucine (Ile/Leu = Xle) rich cyclic octapeptide champacyclin (1a). As 2D nuclear magnetic resonance (NMR) spectroscopy could not fully resolve the structure of (1a), additional information on sequence and configuration of stereocenters were obtained by a combination of multi stage mass spectrometry (MSn) studies, amino acid analysis, partial hydrolysis and subsequent enantiomer analytics with gas chromatography positive chmical ionization/electron impact mass spectrometry (GC-PCI/EI-MS) supported by comparison to reference dipeptides. Proof of the head-to-tail cyclization of (1a) was accomplished by solid phase peptide synthesis (SPPS) compared to an alternatively side chain cyclized derivative (2). Champacyclin (1a) is likely synthesized by a non-ribosomal peptide synthetase (NRPS), because of its high content of (d)-amino acids. The compound (1a) showed antimicrobial activity against the phytopathogen Erwinia amylovora causing the fire blight disease of certain plants

Towards policies that capture the expected value of biomolecular diversity for drug discovery, human health, and well-being

This paper aims to help policy makers with a characterization of the intrinsic value of biodiversity and its role as a critical foundation for sustainable development, human health, and well-being. Our objective is to highlight the urgent need to overcome economic, disciplinary, national, cultural, and regional barriers, in order to work out innovative measures to create a sustainable future and prevent the mutual extinction of humans and other species. We emphasize the pervasive neglect paid to the cross-dependency of planetary health, the health of individual human beings and other species. It is critical that social and natural sciences are taken into account as key contributors to forming policies related to biodiversity, conservation, and health management. We are reaching the target date of Nagoya treaty signatories to have accomplished measures to prevent biodiversity loss, providing a unique opportunity for policy makers to make necessary adjustments and refocus targets for the next decade. We propose recommendations for policy makers to explore novel avenues to halt the accelerated global loss of biodiversity. Beyond the critical ecological functions biodiversity performs, its enormous untapped the repertoire of natural molecular diversity is needed for solving accelerating global healthcare challenges