Fungal secondary metabolite mixtures induced distinct morphological defects in zebrafish embryos. Zebrafish embryos were incubated with fungal secondary metabolite mixtures from 6 hpf onwards. Embryos were imaged at 48 hpf. (A) Control not incubated with a fungal secondary metabolite mixture. (B–H) Examples of developmental defects caused by distinct fungal secondary metabolite mixtures. Note the diversity in developmental defects between samples.

Identification of fusaric acid as bioactive compound from Fusarium proliferatum that induces an undulating notochord in zebrafish embryos. (A) Tg(ntl-gfp) transgenic zebrafish were left untreated or (B) were incubated with fraction 27 of Fusarium proliferatum and (C) fusaric acid (40 µM) from 6 hpf onwards and imaged at 24hpf using a confocal microscope, which highlights the undulating notochord in treated embryos. (D–G) Purification and identification of fusaric acid. (D) Preparative HPLC chromatogram of the secondary metabolite mixture of fusarium proliferatum. The major peak, fraction 27, contains the biologically active compound. (E) MS spectrum of fraction 27 revealing a M + H of 180.2 Da. (F) UV-Vis spectrum of fraction 27 revealing maximum absorption peaks at 202, 225 and 270 nm. (G) ¹H-NMR spectrum of fraction 27.

Reduced body axis extension phenotypes induced by commercially available compounds. Embryos were treated with compounds from 6 hpf onwards and were imaged at 48 hpf.

A dilution range reveals specific effects of compactin and verrucarin A on zebrafish embryogenesis. Zebrafish embryos were treated with different concentrations of (A–E) compactin or (F–J) verrucarin A from 6 hpf onwards and were imaged at 48 hpf. (A) 100 nM, (B) 50 nM, (C) 25 nM, (D), 10 nM, (E) 5 nM compactin. (F) 60 nM, (G) 50 nM, (H) 40 nM, (I) 30 nM, (J) 20 nM verrucarin A. Higher concentrations of compactin or verrucarin A were lethal.

Craniofacial defects in embryos of the “shorter” category. Reduced body axis extension may be due to defects in convergence and extension cell movements, which is accompanied by craniofacial defects. Alcian blue staining was performed and the cartilage was imaged laterally and dorsally to illustrate (A) control, and (B–F) treated embryos.