Bio Battles

by by Nupur Shridhar

Chasing Parasites
In order for Africa to develop, it must begin feeding itself. Difficult, considering its large and disperse population, and its dearth of natural resources—aside, of course, from what foreign nations have extracted from the soil: oil, uranium, gold, and diamonds. On top of all this, African farmers have struggled for decades to save their crops from witchweed, or Striga, a genus of parasitic plants that has infected roughly two-thirds of sub-Saharan Africa’s arable land.

The parasite itself is an evolutionary marvel—growing plants release a hormone called strigolactone. When a plant is near a dormant Striga seed, the parasite releases a hormone that causes germination and attaches to the growing host, which is very quickly leached to death. In order to disinfect their fields, farmers (those who can afford to) often treat the soil with ethylene gas, which stimulates germination in the absence of hosts, causing the Striga seedlings to starve. But one Striga plant can scatter tens of thousands of tiny seeds in a field, and seeds often survive the disinfection process.

Since it’s impossible to fully disinfect a field, scientists have begun looking for alternative ways to protect crops—and, by extension, to create sustainable biological niches wherever people need to eat. According to a study published in last week’s Nature Chemical Biology, researchers at the University of Toronto used the popular plant model Arabidopsis to identify the genes responsible for strigolactone production. They were also able to grow mutants that released less strigolactone—and so were more resistant to Striga infection. Up next: the genetic manipulation of plants in vivo, cross-breeding with wild type alleles, and hopefully, the beginning of something delicious.

Swamp Monster
Last month, the Rhode Island Department of Health announced the season’s first human case of Eastern Equine Encephalitis (EEE), a viral parasite commonly referred to as sleeping sickness. First identified in horses, EEE is transmitted to humans by infected mosquitoes and, like every other incurable brain parasite, is not a pleasant way to go: symptoms include fever, aimless wandering, personality changes, and finally seizures ending with collapse into coma. Approximately 33% of those infected die, and survivors often experience significant brain damage. No word yet on the 20-year-old Newport County local, currently unconscious and in critical condition, who likely encountered an infected mosquito population while hiking through woods in southeastern Massachusetts.
Fortunately, the Massachusetts Department of Health has known for years that the hardwood/freshwater swamps found throughout New England are perfect breeding grounds for Culiseta melanura, the mosquito species that transmits the EEE virus from birds to humans. “The mosquitoes lay their eggs in root cavities that go down into the water level, where there’s plenty of stagnant swamp water and plenty of space for eggs,” says Dr. Alan Gettman, the RI Department of Environmental Management’s mosquito abatement coordinator. Gettman has helped establish a mosquito surveillance program that captures mosquitoes from trapping pools throughout RI and tests them for EEE and a handful of other high-risk diseases, including West Nile virus. “The folks up in Massachusetts actually noticed infected mosquitoes in higher rates, and so early in the season, they launched a large-scale aerial spraying of the entire southeastern area.” says Gettman. “They hardly do that.”

In general, about 200,000 counties do some truck spraying annually, but it’s important to note that if the US didn’t fund mosquito testing sites, more of us might actually have to know of and worry about EEE. “It’s a good thing we had data that told us to step up the spraying this year,” Gettman adds. “It wasn’t until after the spraying in MA had wrapped up that we heard that someone had tested positive for EEE.” It could have been a swarmy summer, but as Gettman points out, “It’s important for people to know that the most effective way for them be safe is to take responsibility for their safety.” The RI Deparment of Health warns that Chapman Swamp, in Westerly, has tested positive for EEE and encourages people to avoid stagnant water, wear protective clothing, and use insect repellent that contains safe levels of DEET. One more reason to look forward to the fall.

Growing Wisdom
In a study published in this month’s Journal of Biological Chemistry, researchers from Japan’s National Institute of Advanced Industrial Science and Technology show that tissue from wisdom teeth can be transformed into stem cells. Since 2006, scientists have been able to sidestep the ethical debate concerning stem cells by inducing “stem-ness” in immature skin and blood cells and other non-embyronic tissue. Most cells, however, do not transform easily, and some researchers believe that the soft pulp in  the center of wisdom teeth (found in all teeth—the root of every tooth ache), which are often extracted anyway, might be the next best way to market stem cells to the public: each of us is born with our very own cache of potentially life-saving cells, already genetically compatible with our bodies, unlike most organ replacement therapies currently available. No entrepreneurial biotech companies offering to store our just teeth yet, but it’s a nice excuse to avoid going to the orthodontist.

-- Nupur Shridhar B'11 lays her eggs in root cavities.