“I’ve had memorable moments where a barracuda’s face ends up firmly fixed in my mind,” says Russ Kerr, Canada Research Chair in Marine Natural Products at the University of Prince Edward Island. But things with teeth aren’t actually at the heart of his marine science research. Rather, “We’re looking to discover novel natural products in the sea and make medicine from them. And to develop production methods that are ecologically sound for the marine environment. It is clearly of fundamental importance to human health to discover new therapeutic agents.
“My interest in the marine environment didn’t really develop until I was doing my post-doc at Stanford,” says the Scottish-born Kerr. “Being there opened my eyes to the field. I had very lab-based scientific training in Calgary before that, but working with Carl Djerassi at Stanford opened my eyes. The ‘father of the Pill,’ he’s one of the most published scientists ever. He was working on the biosynthesis of marine natural products, on unusual sterols, and phospholipids.
“He asked me if I knew how to dive, which I didn’t, so I went off for my first month as a post-doc and trained to scuba dive. He sent me off to Puerto Rico to collect sponges.
“I didn’t even know what I wanted to do when I grew up before going to that lab, but it was there—just talking to the others—that made me realize that the game of academic research was something I wanted to do. And it was Djerassi again, this time just before I left the lab, who said something that really stuck with me. He told me: ‘think big. Don’t try and do incremental work on a problem that’s been addressed by other people.’
“I went into this somewhat naively. There was little literature. We were trying to develop a new field. I worked quite hard in those early years, at Florida Atlantic University, to identify a good set of target compounds. What evolved out of that was a particular class of corals, gorgonian corals, which are the source of terpenes. Terpenes are extremely valuable for their anti-inflammatory and anti-cancer properties but the supply is limited because they are harvested from threatened coral reefs.”
There are, Kerr explains, two aspects to his research. One is fairly simple to define—“the discovery of new therapeutics from organisms in the ocean. These include the macro organisms, sponges, corals, tunicates, algae.”
The other part—the more immediately commercially active part—
relates to supply issues. “The field of marine drug discovery has found that organisms such as sponges and corals are a fantastic new source of chemical structures with new types of biological activity. The problem, though, is that these organisms are often very small, difficult to collect, and the chemicals are very complex structures that we can’t make in the lab by chemical synthesis. We can’t harvest the organism in mass quantities to produce a chemical. So we also have a really novel program growing bacteria from the tissues of corals and sponges and from sediment, with the idea that these bacterial cultures will produce new bioactive natural products.
“To come back to the terpenes, one of our discoveries is that it is not the corals themselves that make these chemicals; it’s a bacterium living within the corals. That is really exciting because we can ferment bacteria on whatever scale we want and solve the supply issue that way.”
A patent arising out of this work was issued this spring. Kerr has received a half-dozen patents in the last five years related to developing sustainable supplies.
There is, he says, “a really good critical mass here at AVC, and very exciting collaborations. We find the potential drugs; others do the biological assessment.” He is working, for example, with Balaji Ramanathan in the Department of Biomedical Sciences at AVC on chemo-therapeutic cancer drugs. He hopes to begin work shortly with AVC’s Tarek Saleh, also in Biomedical Sciences, on neurodegenerative diseases. And UPEI colleague Cai Song, Canada Research Chair in Psychoneuroimmunology, has found that some of the coral-derived terpenes are very promising anti-inflammatories.
“We want a large library of natural products which can be screened for different applications in cancer, or diabetes, or inflammation, and for different kinds of antibiotics and antifungals. The greater the collection, and the wider the screening, the greater the chance we have of finding promising leads. To date the library comes almost exclusively from Florida and the Bahamas. But one of the exciting things for me in coming to PEI is the ability to be living on a small island with waters across the Maritimes unexplored by anyone in the field of marine pharmacology.
“We’re working with other established marine scientists—people in Jeff Davidson’s shellfish research group at AVC, for example. He has a crew that goes diving to monitor mussel socks and tunicates. We have a standing request with them that if they see some sponges or anything that isn’t fouled by other organisms, to collect them for us. If inanimate objects, rocks, pier pilings, oyster cages, and mussel socks are covered in tunicates, for example, but nearby sea lettuces are pristine, it’s probably because sea lettuces produce chemicals that may not have drug potential, but might produce natural anti-fouling compounds that could be incorporated in marine paints. No one else is doing this.”
But none of the work, he points out, is his alone. “I manage,” he says. “I don’t do the lab work. None of this happens without students who work their tails off. The greatest kick I get is when a student comes in my door with a cheesy grin on his or her face saying, ‘Guess what? This worked.’ The interaction with the students: that’s what it’s all about.”
