• Bacterial membrane-derived vesicles attenuate vancomycin activity against methicillin-resistant staphylococcus aureus 

      Kumaraswamy, Monika; Wiull, Kamilla; Joshi, Bishnu; Sakoulas, George; Kousha, Armin; Vaaje-Kolstad, Gustav; Johannessen, Mona; Hegstad, Kristin; Nizet, Victor; Askarian, Fatemeh (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-09-29)
      Methicillin-resistant Staphylococcus aureus (MRSA) has evolved numerous antimicrobial resistance mechanisms and is identified as a serious public health threat by the World Health Organization and U.S. Centers for Disease Control and Prevention. The glycopeptide vancomycin (VAN) remains a cornerstone of therapy for severe MRSA infections despite increasing reports of therapeutic failure in hospitalized ...
    • Biochemical and structural characterisation of a family GH5 cellulase from endosymbiont of shipworm P. megotara 

      Junghare, Madan; Manavalan, Tamilvendan; Fredriksen, Lasse; Leiros, Ingar; Altermark, Bjørn; Eijsink, Vincent; Vaaje-Kolstad, Gustav (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-04-04)
      Background Cellulases play a key role in the enzymatic conversion of plant cell-wall polysaccharides into simple and economically relevant sugars. Thus, the discovery of novel cellulases from exotic biological niches is of great interest as they may present properties that are valuable in the biorefning of lignocellulosic biomass. Results We have characterized a glycoside hydrolase 5 (GH5) domain ...
    • Chitinolytic enzymes contribute to the pathogenicity of Aliivibrio salmonicida LFI1238 in the invasive phase of cold-water vibriosis 

      Skåne, Anna; Edvardsen, Per Kristian Thorén; Cordara, Gabriele; Loose, Jennifer Sarah Maria; Leitl, Kira Daryl; Krengel, Ute; Sørum, Henning; Askarian, Fatemeh; Vaaje-Kolstad, Gustav (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-08-08)
      Background - Aliivibrio salmonicida is the causative agent of cold-water vibriosis in salmonids (Oncorhynchus mykiss and Salmo salar L.) and gadidae (Gadus morhua L.). Virulence-associated factors that are essential for the full spectrum of A. salmonicida pathogenicity are largely unknown. Chitin-active lytic polysaccharide monooxygenases (LPMOs) have been indicated to play roles in both chitin ...
    • Discovery and characterization of a thermostable two-domain GH6 endoglucanase from a compost metagenome 

      Jensen, Marianne Slang; Fredriksen, Lasse; Mackenzie, Alasdair; Pope, Phillip; Leiros, Ingar; Chylenski, Piotr; Williamson, Adele Kim; Christopeit, Tony; Østby, Heidi; Vaaje-Kolstad, Gustav; Eijsink, Vincent (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-05-24)
      Enzymatic depolymerization of recalcitrant polysaccharides plays a key role in accessing the renewable energy stored within lignocellulosic biomass, and natural biodiversities may be explored to discover microbial enzymes that have evolved to conquer this task in various environments. Here, a metagenome from a thermophilic microbial community was mined to yield a novel, thermostable cellulase, named ...
    • Immunization with lytic polysaccharide monooxygenase CbpD induces protective immunity against Pseudomonas aeruginosa pneumonia 

      Askarian, Fatemeh; Tsai, Chih-Ming; Cordara, Gabriele; Zurich, Raymond H.; Bjånes, Elisabet; Golten, Ole; Sørensen, Henrik Vinther; Kousha, Armin; Meier, Angela; Chikwati, Elvis Mashingaidze; Bruun, Jack-Ansgar; Ludviksen, Judith K; Choudhury, Biswa; Trieu, Desmond; Davis, Stanley; Edvardsen, Per Kristian Thorén; Mollnes, Tom Eirik; Liu, George Y.; Krengel, Ute; Conrad, Douglas J.; Vaaje-Kolstad, Gustav; Nizet, Victor (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-07-17)
      Pseudomonas aeruginosa (PA) CbpD belongs to the lytic polysaccharide monooxygenases (LPMOs), a family of enzymes that cleave chitin or related polysaccharides. Here, we demonstrate a virulence role of CbpD in PA pneumonia linked to impairment of host complement function and opsonophagocytic clearance. Following intratracheal challenge, a PA ΔCbpD mutant was more easily cleared and produced less ...
    • The lytic polysaccharide monooxygenase CbpD promotes Pseudomonas aeruginosa virulence in systemic infection 

      Askarian, Fatemeh; Uchiyama, Satoshi; Masson, Helen; Sørensen, Henrik Vinther; Golten, Ole; Bunæs, Anne Cathrine; Mekasha, Sophanit; Røhr, Åsmund Kjendseth; Kommedal, Eirik Garpestad; Ludviksen, Judith Anita; Arntzen, Magnus Øverlie; Schmidt, Benjamin; Zurich, Raymond H.; Van Sorge, Nina M.; Eijsink, Vincent; Krengel, Ute; Mollnes, Tom Eirik; Lewis, Nathan E.; Nizet, Victor; Vaaje-Kolstad, Gustav (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-23)
      The recently discovered lytic polysaccharide monooxygenases (LPMOs), which cleave polysaccharides by oxidation, have been associated with bacterial virulence, but supporting functional data is scarce. Here we show that CbpD, the LPMO of <i>Pseudomonas aeruginosa</i>, is a chitin-oxidizing virulence factor that promotes survival of the bacterium in human blood. The catalytic activity of CbpD was ...
    • Structure and function of a CE4 deacetylase isolated from a marine environment 

      Tuveng, Tina Rise; Rothweiler, Ulli; Udatha, D.B.R.K. Gupta; Vaaje-Kolstad, Gustav; Smalås, Arne O.; Eijsink, Vincent (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-11-06)
      Chitin, a polymer of β(1–4)-linked N-acetylglucosamine found in e.g. arthropods, is a valuable resource that may be used to produce chitosan and chitooligosaccharides, two compounds with considerable industrial and biomedical potential. Deacetylating enzymes may be used to tailor the properties of chitin and its derived products. Here, we describe a novel CE4 enzyme originating from a marine ...