Tenuazonic acid alters immune and physiological reactions and susceptibility to pathogens in Galleria mellonella larvae

AbstractTenuazonic acid (TeA) is synthesized by phytopathogenic and opportunistic fungi and is detected in a broad range of foods. This natural compound is of interest in terms of toxicity to animals, but its mechanisms of action on insects are poorly understood. We administered TeA orally at different concentrations (0.2 –5.0 mg/[gram of a growth medium]) to the model insectGalleria mellonella, with subsequent estimation of physiological, histological, and immunological parameters in different tissues (midgut, fat body, and hemolymph). Susceptibility of the TeA-treated larvae to pathogenic microorganismsBeauveria bassiana andBacillus thuringiensis was also analyzed. The feeding of TeA to the larvae led to a substation delay of larval growth, apoptosis-like changes in midgut cells, and an increase in midgut bacterial load. A decrease in activities of detoxification enzymes and downregulation of genesNox,lysozyme, andcecropin in the midgut and/or hemocoel tissues were detected. By contrast, genesgloverin,gallerimycin, andgaliomycin and phenoloxidase activity proved to be upregulated in the studied tissues. Hemocyte density did not change under the influence of TeA. TeA administration increased susceptibility of the larvae toB. bassiana but diminished their susceptibility toB. thuringiensis. The results indicate that TeA disturbs wax moth gut physiology and immunity and also exerts a systemic action on this insect. Mechanisms underlying the observed changes in wax moth susce...
Source: Mycotoxin Research - Category: Toxicology Source Type: research