P €H`TEXTMOSS @Sea--Quest for Cures--May 15, 2000
Farming Sponges and Cells
May 15, 2000
 
@Sea correspondent/
photographer,
Mark Carroll
 
Several years ago, the science team leading our current expedition uncovered a medicinal metabolite called Discodermalide, hidden within the chemistry of various deep-sea sponges of the genus Discodermia. In subsequent trials, the compound has proven itself to be an effective anti-tumor agent with a
Careful to keep their fins and guages away from the delicate coral, divers Alan Duckworth and Brian Killday scan the reefs of Bonaire.
potential to treat some types of cancer. However, synthetic production of the compound -- a process requiring over 30 steps -- does not look to be a commercially viable option.
 
So the researchers are attacking the supply problem head on. Alan Duckworth, a visiting aquaculture specialist from New Zealand, spends his days scuba diving the local reefs. If he is not underwater, he can be found sealed in a frigid chamber aboard the R/V EDWIN LINK. I talked with him in his icy lab that, by design, emulates conditions in deep waters.
 
"One way to produce a supply of Discodermalide is though sponge aquaculture," Duckworth says. He grabs a plastic tie wrap and suspends one of his sponges in a tank, allowing it to feed freely. "These guys are easily stressed," Duckworth continues. "It's important to keep them happy."
 
Luckily, sponges are colonial animals, meaning that a piece of one sponge can conceivably give rise to a complete animal. But making the process happen in a lab is all new ground. There are no commercial farms anywhere that raise these types of sponges, leaving Duckworth to his own devices as he determines exactly how small a sponge-piece can be and still give rise to a healthy, compound-producing organism. If he succeeds in answering this and a lot of other questions, then "farm-raised" sponges could be harvested for their medicinal compounds as conveniently as milk is collected from cows.
‹‹PREVIEW
‹‹May 8
‹‹May 9
‹‹May 10
‹‹May 11
‹‹May 12
‹‹May 14
‹‹May 15
‹‹May 17
‹‹May 18
‹‹May 19


Working in one of the ship's smaller labs, Cris Waterhouse prepares part of her experiment.


Cris Waterhouse holds one of the small bioreactors in which sponge cells will grow.
Verging on hypothermia, I left the chilly lab and met up with Robin Willoughby, a cell biologist from the Harbor Branch Oceanographic Institution. Thankfully, she works in a warmer lab on the ship's "01" deck. In some respects, Willoughby hopes to accomplish the same thing as Duckworth, only on a cellular level.
 
Since collecting fresh samples during the last week, Willoughby has been busy tearing apart her sponges. Ironically, she destroys (or, more precisely, dissociates) the animals in order to generate living colonies of cells which she grows in a nutrient-rich fluid. Willoughby's methods, applied on a larger scale, could potentially provide large amounts of Discodermalide.
 
In conjunction with Willoughby, Cris Waterhouse -- a bioengineer at the Walter Reed Army Institute of Research in Silver Springs, Maryland -- hopes to grow sponge cells, but in a slightly different manner. Waterhouse is trying to grow cells within hollow-fiber bioreactors. The bioreactors are ingenious little growth chambers with their own fully automated, pump-fed nutrient supply. If it all sounds hi-tech, that's because it is. Waterhouse's group has produced similar systems for life science experiments aboard 15 Space Shuttle missions.
 
The scientists' "farming" experiments have yielded promising early results. With luck and persistence, they will succeed in producing a plentiful source of the medicinal compound. Not only will such success by-pass the need to synthetically produce the drug, it will also alleviate potential pressures on natural sponge populations.
 
There will be more time on dry land to continue these experiments. When out in the field, the emphasis is, understandably, on fieldwork. In the coming days, we will return to the deep-sea and to the reefs of Bonaire before continuing on to the island of Aruba.


Whirring quietly in a corner of the laboratory, a series of bioreactors contains growing sponge-cell colonies.


© 2000, Harbor Branch Oceanographic Institution