About This Project

Heterosigma akashiwo is a unicellular algae that cause Harmful Algal Blooms (HABs) and has been associated with finfish kills for decades. Although no specific toxin has been isolated, its toxicity is considered to be due to variety of compounds. In this study, we would like to analyze biochemical and cellular changes associated with toxicity in H. akashiwo blooms using a metabolomics-proteomics approach to identify potential biotoxin biosynthesis pathways.

Ask the Scientists

What is the context of this research?

A tiny fraction of the diverse microalgal species produce compounds that are toxic to other organisms. These toxic compounds are accumulated and transferred through the food web. Humans, birds and other terrestrial animals that feed on seafood are also at health risk. In the United States, 20% of all food borne disease outbreaks result from seafood consumption, of which half of those are caused by naturally occurring algal toxins. Apart from the health hazards, the costs associated with monitoring, loss of revenue for local fisheries and tourism industry is huge. Thus, it is important to understand the factors that stimulate HABs, the causative agent, methods to detect the toxin in food sample and finally to develop methods for bloom control.

What is the significance of this project?

H. akashiwo is a toxic bloom–forming raphidophyte alga that is reported to cause red tide blooms. In temperate and subtropical embayment, the species usually blooms under summer conditions, when it can reach cell densities as high as 5x10⁸ cells l^-1. For example, in British Columbia waters, H. akashiwo forms annual blooms between June and September, where it kills farmed salmon. Some of the raphidophycean species like Fibrocapsa japonica are known to produce neurotoxic, haemolytic and haemagglutinating compounds. Even H. akashiwo is also suspected to produce brevetoxin like compounds. Therefore, it is necessary to identify factors contributing to toxin production and biosynthetic pathways associated with toxicity by H. akashiwo.

What are the goals of the project?

1) Analysis of cultures for toxicity: Utilizing the strains available in our laboratory, culture conditions will be modified for enhancing the toxin production. The conditions that promote toxin production as well as the conditions that do not will be identified and used further analysis. 2) Metabolite and protein profiling: Metabolomics analysis will help us understand the metabolites, the products of different biosynthetic pathway, whereas proteomics analysis will provide the enzymes that are involved in the biosynthetic pathways. Therefore, a combined comparative metabolomics and proteomics will pave way for the comprehensive understanding of toxin biosynthesis and the identification of potential toxins within this species.