• Callyaerin G, a new cytotoxic cyclic peptide from the marine sponge Callyspongia aerizusa

      Ibrahim, Sabrin R. M.; Edrada-Ebel, RuAngelie; Mohamed,Gamal A.; Youssef, Diaa T. A; Wray, Victor; Proksch, Peter; Helmholz Centre for Infection research, D-38124 Braunschweig, Germany (Arkat, 2008-04-16)
    • Formation and Identification of Interfacial-Active Glycolipids from Resting Microbial Cells

      Li, Zu-Yi; Lang, Siegmund; Wagner, Fritz; Witte, Ludger; Wray, Victor (1984-09)
    • Induced production of depsipeptides by co-culturing Fusarium tricinctum and Fusarium begoniae

      Wang, Jian-ping; Lin, Wenhan; Wray, Victor; Lai, Daowan; Proksch, Peter (2013-10-01)
    • Isolation of isomangiferin from honeybush (Cyclopia subternata) using high-speed counter-current chromatography and high-performance liquid chromatography.

      de Beer, Dalene; Jerz, Gerold; Joubert, Elizabeth; Wray, Victor; Winterhalter, Peter; ARC Infruitec-Nietvoorbij, Stellenbosch, South Africa. dbeerd@arc.agric.za (2009-05-08)
      Isomangiferin was isolated from Cyclopia subternata using a multi-step process including extraction, liquid-liquid partitioning, high-speed counter-current chromatography (HSCCC) and semi-preparative reversed-phase high-performance liquid chromatography (HPLC). Enrichment of phenolic compounds in a methanol extract of C. subternata leaves was conducted using liquid-liquid partitioning with ethyl acetate-methanol-water (1:1:2, v/v). The enriched fraction was further fractionated using HSCCC with a ternary solvent system consisting of tert-butyl methyl ether-n-butanol-acetonitrile-water (3:1:1:5, v/v). Isomangiferin was isolated by semi-preparative reversed-phase HPLC from a fraction containing mostly mangiferin and isomangiferin. The chemical structure of isomangiferin was confirmed by LC-high-resolution electrospray ionization MS, as well as one- and two-dimensional NMR spectroscopy.
    • Preparative Isolation and Purification of Flavonoids and Protocatechuic Acid from Sea Buckthorn Juice Concentrate (Hippophae rhamnoides) by High-Speed Counter-Current Chromatography

      Gutzeit, D.; Wray, Victor; Winterhalter, P.; Jerz, Gerold; Institute of Food Chemistry, Technical University of Braunschweig (Springer Science Business Media, 2007)
    • Production and modification of bioactive surfactants

      LANGER, Olaf; Palme, Olov; Wray, Victor; Tokuda, Harukuni; Lang, Sigmund (2007-09-20)
    • Pullularins E and F, Two New Peptides from the Endophytic Fungus Bionectria ochroleuca Isolated from the Mangrove Plant Sonneratia caseolaris.

      Ebrahim, Weaam; Kjer, Julia; El Amrani, Mustapha; Wray, Victor; Lin, Wenhan; Ebel, Rainer; Lai, Daowan; Proksch, Peter; Institute of Pharmaceutical Biology and Biotechnology, Heinrich-Heine University, Universitaetsstrasse 1, D-40225 Duesseldorf, Germany; Email: weel-001@uni-duesseldorf.de or weaamnabil@mans.edu.eg (W.E.); jacob.julia@web.de (J.K.); mustapha.elamrani@uni-duesseldorf.de (M.E.A.). (2012-05)
      Chemical investigation of the EtOAc extract of the endophytic fungus Bionectria ochroleuca, isolated from the inner leaf tissues of the plant Sonneratia caseolaris (Sonneratiaceae) from Hainan island (China), yielded two new peptides, pullularins E and F (1 and 2) together with three known compounds (3-5). The structures of the new compounds were unambiguously determined on the basis of one- and two-dimensional NMR spectroscopy as well as by high-resolution mass spectrometry. The absolute configurations of amino acids were determined by HPLC analysis of acid hydrolysates using Marfey's method. The isolated compounds exhibited pronounced to moderate cytotoxic activity against the mouse lymphoma cells (L5178Y) with EC(50) values ranging between 0.1 and 6.7 µg/mL.
    • Solution structure of the Equine Infectious Anemia Virus p9 protein: a rationalization of its different ALIX binding requirements compared to the analogous HIV-p6 protein

      Sharma, Alok; Bruns, Karsten; Röder, René; Henklein, Peter; Votteler, Jörg; Wray, Victor; Schubert, Ulrich (2009-12-17)
      Abstract Background The equine infection anemia virus (EIAV) p9 Gag protein contains the late (L-) domain required for efficient virus release of nascent virions from the cell membrane of infected cell. Results In the present study the p9 protein and N- and C-terminal fragments (residues 1-21 and 22-51, respectively) were chemically synthesized and used for structural analyses. Circular dichroism and 1H-NMR spectroscopy provide the first molecular insight into the secondary structure and folding of this 51-amino acid protein under different solution conditions. Qualitative 1H-chemical shift and NOE data indicate that in a pure aqueous environment p9 favors an unstructured state. In its most structured state under hydrophobic conditions, p9 adopts a stable helical structure within the C-terminus. Quantitative NOE data further revealed that this α-helix extends from Ser-27 to Ser-48, while the N-terminal residues remain unstructured. The structural elements identified for p9 differ substantially from that of the functional homologous HIV-1 p6 protein. Conclusions These structural differences are discussed in the context of the different types of L-domains regulating distinct cellular pathways in virus budding. EIAV p9 mediates virus release by recruiting the ALG2-interacting protein X (ALIX) via the YPDL-motif to the site of virus budding, the counterpart of the YPXnL-motif found in p6. However, p6 contains an additional PTAP L-domain that promotes HIV-1 release by binding to the tumor susceptibility gene 101 (Tsg101). The notion that structures found in p9 differ form that of p6 further support the idea that different mechanisms regulate binding of ALIX to primary versus secondary L-domains types.
    • Structural characterization of 13(2)-hydroxy-(13(2)-S)-phaeophytin-a from leaves and stems of Amaranthus tricolor isolated by high-speed countercurrent chromatography

      Jerz, Gerold; Arrey, Tabiwang N.; Wray, Victor; Du, Qizhen; Winterhalter, Peter; Helmholtz Zentrum für Infektionsforschung GmbH (Elsevier Science, 2007)
    • Structural characterization of the exopolysaccharide PS-EDIV from Sphingomonas pituitosa strain DSM 13101.

      Schultheis, Ellen; Dreger, Michael A; Nimtz, Manfred; Wray, Victor; Hempel, Dietmar C; Nörtemann, Bernd; Institute of Biochemical Engineering, Technical University of Braunschweig, Braunschweig, Germany. (2008-04)
      Members of the bacterial genus Sphingomonas are known to produce highly viscous polysaccharides in solution. The exopolysaccharide PS-EDIV was produced by Sphingomonas pituitosa strain DSM 13101, purified using centrifugation, and precipitation and its structure was elucidated by 1D and 2D NMR techniques and chemical microderivatization combined with various mass spectrometric techniques. The following repeating unit of the polysaccharide could be identified: [formula: see text]. In addition, the polysaccharide also contains acetyl and glyceryl groups whose exact positions were not determined. PS-EDIV is similar in structure to a known exopolysaccharide but differs in being the first bacterial polysaccharide in which two different glucuronic acids are combined. It caused a high viscosity of the culture broth after cultivation for 48 h, although a gelation was not observed.