OUR RESEARCH
Conservation Ecology and Behaviour
Our research involves both field work (in the marine environment) and our captive breeding population at Flinders University in South Australia.
Our main focus of interest is in understanding the symbiotic relationship between clownfish and their sea anemone hosts. The association between sea anemones and clownfish is a classic example of a mutualistic interaction, where both symbionts appear to benefit from living with each other. However this relationship is complex, and exactly how clownfish manage to live unharmed in the toxic environment of their anemone is a question that remains unsolved. Apart from only a few other fish and crustacean species, the venom contained in the nematocysts of anemones is toxic enough to kill other fish that make contact with their tentacles.[1] So, how do clownfish do it?
Our research on anemone toxicity has indicated clownfish have a preference for anemone species that have a moderate level of toxicity and interestingly, the toxicity within symbiotic anemone species may be lower than in anemones that don’t have a fish to help protect them. [2]
How this relationship evolved (and it has been going on for about 10 million years!), how clownfish align themselves to different species of anemone, how clownfish choose a particular anemone, and what anemones are more desirable than others are all important for helping us understand how this system functions and what parameters are necessary for this unique symbiotic relationship to continue to exist in the wild.
Aquaculture and Sustainable Fisheries
During the last decade, we have implemented innovative techniques that have improved the breeding success and survival of captive bred clownfish for the Australian aquaria market.
This project includes expanding our aquaculture and biotechnology clownfish research to enable increased production and the development of new characteristics which are currently in market demand.
Through improving aquaculture conditions with respect to water quality and nutrition we aim to increase optimal breeding and reproductive output. In addition, we are conducting research into how to improve the care of clownfish through monitoring their behaviour and determining mechanisms to reduce interactions that have been shown to negatively impact pair bonding and egg laying.
Understanding the genetics of clownfish with a focus on reducing the effects of inbreeding will also allow for a healthier and more vibrant captive bred population.
Using host anemones as bioactive products in anticancer research
Our discoveries associated with anemone toxicities were followed by investigations into the anticancer properties of different species of host anemones. The remarkable ability of clownfish to live in the toxic environment of anemones led us to suspect that these host anemones might be somehow special.
We found all clownfish host anemones that we tested have anticancer properties, but the venom from the Magnificent anemone (Heteractis magnifica), also known as the Ritteri anemone, showed strong cytotoxic effects on all cancer cell-lines studied (breast, lung, skin). Given it is a very large anemone that is fairly easy to obtain and keep alive in captivity, it has become our model species. What was a truly fabulous finding was when we trialled the effect of anemone venom on normal cells and found they didn’t have nearly the same negative response, making this venom a potential candidate for further development toward drug therapeutics.[3]
Determining the mechanism by which anemone venom kills cancer cells has been the next step in our research and through various assays, we have found that venom from the Magnificent anemone kills cancer cells through a natural phenomenon called Apoptosis (programmed cell death), and a key event associated with this mechanism is mitochondrial dysfunction. Treating cancer with natural pharmaceuticals that work through normal processes rather than non-natural remedies are clearly important to drug developments for the future.[4]
If you would like to support this research program, please donate here.
[1] Nedosyko, AM, Young, JE, Edwards, JW & Burke da Silva, K 2014, 'Searching for a toxic key to unlock the mystery of anemonefish and anemone symbiosis', PloS one, vol. 9, no. 5, p. e98449.
[2] Nedosyko, Young, Edwards, & Burke da Silva, op. cit., p. e98449.
[3] Ramezanpour, M, Burke da Silva, K & Sanderson, BJ 2014, 'Marine bioactive products as anti-cancer agents: Effects of sea anemone venom on breast and lung cancer cells', Cancer Cell & Microenvironment, vol. 1, no. 1.
[4] Ramezanpour, M, Da Silva, KB & Sanderson, BJ 2014, 'Venom present in sea anemone (Heteractis magnifica) induces apoptosis in non-small-cell lung cancer A549 cells through activation of mitochondria-mediated pathway', Biotechnology letters, vol. 36, no. 3, pp. 489-95.