- News Home
12 December 2013 1:00 pm ,
Vol. 342 ,
The iconic 125-year-old Lick Observatory on Mount Hamilton near San Jose, California, is facing the threat of closure...
Recent results from the Curiosity Mars rover have helped scientists formulate a plan for the next phase of its mission...
A new, remarkably powerful drug that cripples the hepatitis C virus (HCV) came to market last week, but it sells for $...
In pretoothbrush populations, gumlines would often be marred by a thick, visible crust of calcium phosphate, food...
Evolutionary biologists have long studied how the Mexican tetra, a drab fish that lives in rivers and creeks but has...
Victorian astronomers spent countless hours laboriously charting the positions of stars in the sky. Such sky mapping,...
In an ambitious project to study 1000 years of sickness and health, researchers are excavating the graveyard of the now...
Stefan Behnisch has won awards for designing science labs and other buildings that are smart, sustainable, and...
- 12 December 2013 1:00 pm , Vol. 342 , #6164
- About Us
11 December 1997 6:30 pm
Parasites that cause skin rashes in people and infest ducks can commandeer DNA in the brains of snails and order the unwitting mollusks to give up sex. The findings, in the current issue of the Proceedings of the National Academy of Sciences, suggest that some parasites can enhance their ability to survive by hijacking the controls of specific host genes.
Wormlike creatures named Trichobilharzia ocellata spend part of their life cycle in the flesh of small freshwater snails (Lymnaea stagnalis). Previous studies had shown that snails with the parasites forgo sex, allowing them to grow more rapidly. At the same time, "within 1 1/2 hours of [the parasite] entering the host, gene expression is significantly and selectively affected," says Marijke de Jong-Brink, a neurobiologist at Vrije University in Amsterdam.
Hoping to link these two observations, Jong-Brink's team exposed snails to a parasite-filled bath. They removed the snails' brains after various durations to measure levels of mRNAs, which translate the DNA blueprint into a template for building proteins. In the parasite-ridden snails, mRNA levels shot up, with some mRNA types exceeding by three times the level of those in healthy snails. The parasite may be releasing a chemical, says Jong-Brink, "that stimulates or inhibits special genes in the host central nervous system, either directly or indirectly." These genes are involved in reproduction and growth regulation.
The finding reinforces the view that "parasites--somewhat like viruses--can force their hosts to act to their benefit," says Viktor Mutt, a medical biochemist at the Karolinska Institute in Stockholm. The findings could have implications for a similar species of parasite that causes schistosomiasis, a debilitating disease that threatens one out of six people in some developing countries.