Toxicity effects of hydrophilic algal lysates from Coolia tropicalis on marine medaka larvae (Oryzias melastigma)

Aquat Toxicol. 2021 May:234:105787. doi: 10.1016/j.aquatox.2021.105787. Epub 2021 Feb 23.

Abstract

Coolia tropicalis is a species of benthic and epiphytic toxic algae, which can produce phycotoxins that intoxicate marine fauna. In this study, the potential toxic effects of C. tropicalis on fish were investigated using larval marine medaka (Oryzias melastigma) as a model to evaluate fish behavior, physiological performance, and stress-induced molecular responses to exposure to two sublethal concentrations (LC10 and LC20) of hydrophilic algal lysates. Exposure to C. tropicalis lysates inhibited swimming activity, activated spontaneous undirected locomotion, altered nerve length ration, and induced early development abnormalities, such as shorter eye diameter, body as well as axon length. Consistent with these abnormalities, changes in the expression of genes associated with apoptosis (CASPASE-3 and BCL-2), the inflammatory response (IL-1β and COX-2), oxidative stress (SOD), and energy metabolism (ACHE and VHA), were also observed. This study advances our understanding of the mechanisms of C. tropicalis toxicity in marine fish in the early life stages and contributes to future ecological risk assessments of toxic benthic dinoflagellates.

Keywords: Apoptosis; Developmental toxicity; Marine medaka; Swimming activity; Toxic dinoflagellate.

MeSH terms

  • Animals
  • Dinoflagellida / metabolism*
  • Fish Proteins / genetics
  • Fish Proteins / metabolism
  • Gene Expression Regulation / drug effects
  • Hydrophobic and Hydrophilic Interactions
  • Larva / drug effects*
  • Larva / physiology
  • Locomotion / drug effects
  • Oryzias / growth & development*
  • Oryzias / physiology
  • Proto-Oncogene Proteins c-bcl-2 / genetics
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • Superoxide Dismutase / genetics
  • Superoxide Dismutase / metabolism
  • Toxins, Biological / toxicity*
  • Tumor Necrosis Factor-alpha / genetics
  • Tumor Necrosis Factor-alpha / metabolism

Substances

  • Fish Proteins
  • Proto-Oncogene Proteins c-bcl-2
  • Toxins, Biological
  • Tumor Necrosis Factor-alpha
  • Superoxide Dismutase