Biological Activity of Lipids Extracted from Two Isolates of Fusarium oxysporum (Environmental and Clinical) in Galleria mellonella

摘要

The species complex Fusarium oxysporum (Hypocreales: Nectriaceae) includes plant pathogens of agronomic importance and opportunistic animal and human pathogens. Considering this trans-kingdom capacity, in the present work, we evaluated the virulence of the conidia and the biological activity of lipid extracts from two isolates (environmental and clinical) of F. oxysporum. This evaluation was performed on larvae of Galleria mellonella model, injecting conidia of both isolates via hemocoel in concentrations of 1×104, 1×105, 1×106 and 1×107 conidia/mL. The extracts were characterized by GC and UHPLC-MS and evaluated on G. mellonella in concentrations of 1×102, 1×103 and 1×104 μg/mL. Greater mortality was observed with conidia of environmental isolate than with those of clinical isolate, although with both isolates were observed extra cuticular growth of mycelium in dead caterpillars and colonies of F. oxysporum were recovered from them. It was also found that the lipid extract obtained with methanol from environmental isolate caused prolonged melanization and larval mortality. The lipidomic characterization showed significant differences between the extracts in the composition of phospholipids and their index of unsaturation, finding a greater number of phospholipid species and a higher unsaturation index for the clinical isolate than for the environmental isolate. Co-stimulus of methanol lipid extract and conidia of the environmental isolate was also evaluated and mortality of the whole larvae was obtained, which suggests a synergic effect between lipids and conidia.