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Tribolium castaneum defensins are primarily active against Gram-positive bacteria

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    0451350 - BC-A 2016 RIV US eng J - Journal Article
    Tonk, M. - Knorr, E. - Cabezas-Cruz, A. - Valdés, James J. - Kollewe, C. - Vilcinskas, A.
    Tribolium castaneum defensins are primarily active against Gram-positive bacteria.
    Journal of Invertebrate Pathology. Roč. 132, NOV 2015 (2015), s. 208-215. ISSN 0022-2011
    R&D Projects: GA MŠk(CZ) EE2.3.30.0032
    Institutional support: RVO:60077344
    Keywords : Antimicrobial peptides * Defensin * Innate immunity * Insects * Tribolium castaneum * Gram-positive bacteria
    Subject RIV: EI - Biotechnology ; Bionics
    Impact factor: 2.198, year: 2015

    The red flour beetle Tribolium castaneum is a destructive insect pest of stored food and feed products, and a model organism for development, evolutionary biology and immunity. The insect innate immune system includes antimicrobial peptides (AMPs) with a wide spectrum of targets including viruses, bacteria, fungi and parasites. Defensins are an evolutionarily-conserved class of AMPs and a potential new source of antimicrobial agents. In this context, we report the antimicrobial activity, phylogenetic and structural properties of three T. castaneum defensins (Def1, Def2 and Def3) and their relevance in the immunity of T. castaneum against bacterial pathogens. All three recombinant defensins showed bactericidal activity against Micrococcus luteus and Bacillus thuringiensis serovar tolworthi, but only Def1 and Def2 showed a bacteriostatic effect against Staphylococcus epidermidis. None of the defensins showed activity against the Gram-negative bacteria Escherichia coli and Pseudomonas entomophila or against the yeast Saccharomyces cerevisiae. All three defensins were transcriptionally upregulated following a bacterial challenge, suggesting a key role in the immunity of T. castaneum against bacterial pathogens. Phylogenetic analysis showed that defensins from T. castaneum, mealworms, Udo longhorn beetle and houseflies cluster within a well-defined clade of insect defensins. We conclude that T. castaneum defensins are primarily active against Gram-positive bacteria and that other AMPs may play a more prominent role against Gram-negative species.
    Permanent Link: http://hdl.handle.net/11104/0252527