The zebrafish (Danio rerio) embryo as a model system for identification and characterization of developmental toxins from marine and freshwater microalgae

Abstract

The zebrafish (Danio rerio) embryo has emerged as an important model of vertebrate development. As such, this model system is finding utility in the investigation of toxic agents that inhibit, or otherwise interfere with, developmental processes (i.e. developmental toxins), including compounds that have potential relevance to both human and environmental health, as well as biomedicine. Recently, this system has been applied increasingly to the study of microbial toxins, and more specifically, as an aquatic animal model, has been employed to investigate toxins from marine and freshwater microalgae, including those classified among the so-called "harmful algal blooms" (HABs). We have developed this system for identification and characterization of toxins from cyanobacteria (i.e. "blue-green algae") isolated from the Florida Everglades and other freshwater sources in South and Central Florida. Here we review the use of this system as it has been applied generally to the investigation of toxins from marine and freshwater microalgae, and illustrate this utility as we have applied it to the detection, bioassay-guided fractionation and subsequent characterization of developmental toxins from freshwater cyanobacteria.

High-Resolution Magic Angle Spinning Nuclear Magnetic Resonance of Intact Zebrafish Embryos Detects Metabolic Changes Following Exposure to Teratogenic Polymethoxyalkenes from Algae

“…10,11,[13][14][15][16] Briefly, 100 embryos (12 h postfertilization [hpf]) per replicate (n = 4) were exposed in 35-mm-diameter polystyrene dishes to 20 lg/mL of PMA (in E3 medium 21 ) for 24 h. Exposure concentration was based on previously determined teratogenicity of PMA and specifically represent concentrations that are not acutely toxic (i.e., teratogenic or lethal) to minimize metabolic changes associated with mortality or severe development deformities.…”

“…[7][8][9] In particular, embryonic and subsequent larval stages have proven particularly useful for characterizing teratogenicity (i.e., developmental toxicity). 8,9 With respect to the current study, the zebrafish embryo teratogenicity assay (ZETA) has been specifically used in the investigation of toxic, and specifically, teratogenic metabolites from marine and freshwater algae, including cyanobacteria, 10 and has enabled both characterization of known algal toxins [11][12][13] and identification (through screening, bioassay-guided isolation, and chemical/toxicological characterization) of otherwise unknown toxic metabolites. [14][15][16] In one such study, ZETA was used to identify a family of teratogenic secondary metabolites, namely, the polymethoxy-1-alkenes (PMAs), and subsequently demonstrate a taxonomically widespread distribution of these metabolites among both prokaryotic cyanobacteria and eukaryotic algae (i.e., Chlorophyta or green algae).…”

Developmental toxicity and alteration of gene expression in zebrafish embryos exposed to PFOS

“…In addition, the zebrafish genome has been sequenced and genetic information is rapidly accumulating (http://zfin.org), which places this freshwater fish in a privileged position for toxicological studies (Berry et al, 2007). Therefore, it is feasible to select toxicological endpoints to find the genes that may be involved in toxicant exposure.…”

“…Therefore, it is feasible to select toxicological endpoints to find the genes that may be involved in toxicant exposure. Recently, zebrafish embryos have been employed for rapid and high-throughout screening of compounds for developmental toxicity and mechanisms of toxicant exposure, including β-naphthoflavone (Voelker et al, 2007), polybrominated diphenyl ethers (Lema et al, 2007), algal toxins (Berry et al, 2007), dioxins (Bello et al, 2004), polycyclic aromatic hydrocarbons (Incardona et al, 2005), pesticides , heavy metals (Chan and Cheng, 2003;Linbo et al, 2006) and carbon nanotubes (Cheng et al, 2007).…”

G 2 /M cell cycle arrest on HT-29 cancer cells and toxicity assessment of triphenylphosphanegold(I) carbonimidothioates, Ph 3 PAu[SC(OR) = NPh], R = Me, Et, and iPr, during zebrafish development

“…Over and above these considerations, zebrafish embryos have a high degree of homology to the human genome, which ensures this living organism is useful for toxicological studies [52,53]. Representative images of zebrafish embryos treated with 1-3 at concentrations 0.625, 1.25, 2.5, and 5.0 µM are shown in Fig.…”