Just add water.
That's all it takes to hatch fish embryos in a kit developed by the Fort Detrick-based U.S. Army Center for Environmental Health Research to help test for water toxicity, according to scientists.
The Army was awarded a patent for the device, called a hatching kit for toxicity test, on Nov. 5 after more than a decade of work. The kit holds embryos from a certain kind of killifish found in the coastal lowlands of Tanzania and Kenya in a suspended state — known as diapause — for long periods. They can then be rapidly reactivated.
Testing can be completed in as little as 48 hours, Tom Shedd, a now-retired inventor of the device, said in a phone interview. If the product of the embryos survive, the water being tested is considered nontoxic, according to the patent filing.
They are "fully developed fish eggs that just don't hatch," Shedd said. "They don't have to be in water. They can be in a petri dish, peat moss."
Killifish eggs are known for their ability to survive erratic climates, including complete drying out. While using fish to test for toxicity is not new, such work can require intensive cultivation and substantial time and resources to maintain and monitor, according to the patent filing.
The Army has licensed the patent to Diapause Research Foundation, a Pensacola, Fla.-based business, through a technology transfer program to allow for additional commercial development, according to Sara Langdon, a technology transfer associate for the U.S. Army Medical Research and Materiel Command's Office of Research and Technology Applications.
The Army's device offers a method similar to what's already required by the U.S. Environmental Protection Agency, USACEHR research biologist Mark Widder said. The EPA uses fathead minnows to test for toxins in wastewater discharges and at Superfund sites, he said.
"The killifish test provides a quick, simple, and ready-to-use test method to make sure toxicants are not polluting streams, rivers at water treatment facility intakes and wastewater discharges," Widder said.
November's patent award follows on another the Army received in 2006 for the method by which the killifish embryos are put into diapause in the lab versus in nature. Shedd said that work may have even larger future implications in areas of cancer and other research.