Plant virus spreads by making life easy for crop pests

“Researchers at The Rockefeller University have found that βC1, a toxic protein produced by the tomato yellow leaf curl China virus (TYLCCV), mimics the behavior of one of two different molecules that govern the development of leaf shape and vein structure. In doing so, it throws the plants off course, causing the unseemly curling and crumpling of leaves and the production of sterile flowers. But it also suppresses the plants’ jasmonic acid response, a defense mechanism against pests feeding on the plants. The result is that the pests — in this case whiteflies that plague tobacco plants — flourish in the diseased crop, spreading the virus faster and faster.”


Collapse of a fish population after exposure to a synthetic estrogen (2007)


Municipal wastewaters are a complex mixture containing estrogens and estrogen mimics that are known to affect the reproductive health of wild fishes. Male fishes downstream of some wastewater outfalls produce vitellogenin (VTG) (a protein normally synthesized by females during oocyte maturation) and early-stage eggs in their testes, and this feminization has been attributed to the presence of estrogenic substances such as natural estrogens [estrone or 17β-estradiol (E2)], the synthetic estrogen used in birth-control pills [17α-ethynylestradiol (EE2)], or weaker estrogen mimics such as nonylphenol in the water. Despite widespread evidence that male fishes are being feminized, it is not known whether these low-level, chronic exposures adversely impact the sustainability of wild populations. We conducted a 7-year, whole-lake experiment at the Experimental Lakes Area (ELA) in northwestern Ontario, Canada, and showed that chronic exposure of fathead minnow (Pimephales promelas) to low concentrations (5–6 ng·L−1) of the potent 17α-ethynylestradiol led to feminization of males through the production of vitellogenin mRNA and protein, impacts on gonadal development as evidenced by intersex in males and altered oogenesis in females, and, ultimately, a near extinction of this species from the lake. Our observations demonstrate that the concentrations of estrogens and their mimics observed in freshwaters can impact the sustainability of wild fish populations.”

Cutting Trees for the Early Birds

“U.S. Forest Service scientists recently published the results of one of the longest studies conducted on the effects of multiple forest harvest methods on early successional bird species. Published online in Forest Ecology and Management, the articleby Forest Service Southern Research Station research wildlife biologist Roger Perry and retired scientist Ron Thill presents findings from an 18-year study in pine-dominated stands on federal lands in Arkansas and Oklahoma.”

The New Normal

“No one is sure how much of Earth is covered by novel ecosystems, but Erle Ellis, a map specialist at the University of Maryland, has taken a stab at quantifying it. Defining novel ecosystems as “lands without agricultural or urban use embedded within agricultural and urban regions,” Ellis estimates that at least 35 percent of the globe is covered with them. Their share of the planet will probably expand, and many ecologists think that these novel ecosystems are worthy of study and, in some cases, protection.”