Herself’s Houston Garden

The sap-sucking insects manage this unexpected feat thanks to ancestors that incorporated genes from a fungus into their own DNA more than 100 million years ago, says Nancy Moran of the University of Arizona in Tucson. Both pea aphids and peach aphids carry genes that make nutrients called carotenoids, she and Arizona colleague Tyler Jarvik report in the April 30 Science.

“To my knowledge, this is the first report of an animal that can synthesize its own carotenoids,” says evolutionary biologist Takema Fukatsu of the National Institute of Advanced Industrial Science and Technology in Tsukuba, Japan.
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Carotenoids, a brightly colored group of molecules including beta-carotene and lycopene, are powerful antioxidants and immune-system boosters. Carotenoid pigments can put the reds and yellows into feathers and other show-off tissues for courting displays, and they catch light in the human retina. Yet in essence, “there’s only one way to make carotenoids in all of nature,” Moran says, and animals apparently lost the basic toolkit long ago in their evolutionary history.

Many microorganisms, fungi and plants still have the power, however. Carotenoids put the blush in tomatoes, and the fiery range of yellows, reds and oranges into flowers. Read more

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Lateral Transfer of Genes from Fungi Underlies Carotenoid Production in Aphids ( paper $)

Some insect pests are very specialized—usually feasting on one crop. Many are named after that one particular crop that they ingest most—like pickleworms, melonworms, and sweetpotato weevils. Unfortunately for growers of ornamentals, soybean, maize, fruit, and vegetables, the Japanese beetle is not a picky eater. It feeds on nearly 300 plant species in almost 80 plant families.

The beetle, Popillia japonica, is by far the most destructive pest of ornamental and turf plants in the eastern United States, with more than $450 million spent each year to control it and replace damaged plants.

But there is hope, since there is one plant that the hungry little critter may want to avoid—the geranium, Pelargonium zonale. Though its lovely, colorful flowers are very attractive for all and profitable for growers, the flowers are deadly to the beetles. Within 30 minutes of consuming the petals, the beetle rolls over on its back, its legs and antennae slowly twitch, and it remains paralyzed for several hours. When paralyzed under laboratory conditions, the beetles typically recover within 24 hours, but they often die under field conditions because predators spot and devour them.

Technicians prepare geranium leaves for grinding, extracting, and filtering, while entomologist (background) separates and purifies the active phytochemicals: Click here for full photo caption.
Technicians Gerald Hammel (left) and Alane Robinson prepare geranium leaves for grinding, extracting, and filtering, while entomologist Christopher Ranger (background) separates and purifies the active phytochemicals. (D1585-4)

The poisoning effect of geranium flowers on beetles is not a new discovery; it has been reported in scientific papers dating back to the 1920s. But the phenomenon has not been studied in depth—how or why it happens—until recently, when Agricultural Research Service scientists in Ohio picked up where scientists left off more than half a century ago.

Currently, Chris Ranger, an entomologist in the ARS Application Technology Research Unit in Wooster, is working on a natural, botanical formulation for controlling the beetles based on paralytic compounds isolated from geraniums. Patent rights are being pursued. Ranger is collaborating with Ajay Singh, a natural products chemist from Rutgers, The State University of New Jersey.

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Not only might grass do an excellent job of removing antibiotics from our water supplies but the tetracycline fed grass grew much faster.

What goes in must come out, and when animals are given antibiotics, they can find their way into the water supply. Now, a Michigan Tech senior has identified one way to sop them up.

Working with Rupali Datta, an associate professor of biological sciences, Smith designed an experiment using sterile vetiver grass to address the issue. Vetiver is a native of India often grown in artificial wetlands to cleanse wastewater. It is both vigorous and noninvasive, posing little risk to indigenous plants. It’s also been used to clean up some tough customers, including TNT.

Smith grew vetiver hydroponically in a greenhouse, exposing the plants to various concentrations of tetracycline and monensin, two antibiotics commonly used to treat dairy cattle. “We wanted to see if the vetiver would uptake them, because if you give these antibiotics to cows, 70 percent is excreted in active form,” Smith says. “We worry about them leaching into the groundwater, getting into drinking water and compounding the problem of antibiotic resistance.”

At the end of the 12-week study, all of the tetracycline and 95.5 percent of the monensin had disappeared from the hydroponic solution. Tests showed that the vetiver had taken and metabolized both drugs up into the plant tissue. The results are preliminary, says Smith, but they show that vetiver holds promise for remediating antibiotics in wastewater.

Smith also recorded a peculiar side effect. “The plants in the tetracycline solution grew faster, much faster than the controls,” she says. “The plans in monensin grew somewhat faster, but not as much.”

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