Crusty Alga Uncovers Sea-Ice Loss That Inhibits COX-2

Selections from the RESEARCH HIGHLIGHTS scientific literature PHARMACOLOGY Painkiller kills the bad effects of pot Marijuana’s undesirable effects NICK CALOYIANUS on the brain can be overcome by using painkillers similar to ibuprofen, at least in mice. Chu Chen and his colleagues at Louisiana State University Health Sciences Center in New Orleans treated mice with THC, marijuana’s main active ingredient. They found that THC impaired the animals’ memory and the efficiency of their neuronal signalling, probably by stimulating the enzyme COX-2. The authors reversed these negative effects — and were able to maintain marijuana’s benefits, such as reducing CLIMATE SCIENCES neurodegeneration — when they also treated the mice with a drug, similar to ibuprofen, Crusty alga uncovers sea-ice loss that inhibits COX-2. The authors suggest that the Like tree rings, layers of growth in a long-lived marine alga Clathromorphum compactum benefits of medical marijuana Arctic alga may preserve a temperature record (pictured). It can live for hundreds of years and could be enhanced with the use of past climate. Specimens from the Canadian builds a fresh layer of crust each year. of such inhibitors. Arctic indicate that sea-ice cover has shrunk The thickness of each layer, and the ratio of Cell 155, 1154–1165 (2013) drastically in the past 150 years — to the lowest magnesium to calcium within it, are linked to levels in the 646 years of the algal record. water temperature and the amount of sunlight PALAEOECOLOGY Satellite records of the Arctic’s shrinking the organism receives. The discovery suggests sea-ice cover date back only to the late 1970s. a new way to calculate how much polar sea ice Dung reveals Jochen Halfar of the University of Toronto at existed hundreds of years ago. goats’ last days Mississauga, Canada, and his colleagues have Proc. Natl Acad. Sci. USA http://doi.org/p6g found a new palaeoclimate proxy in the coralline (2013) Climate change, rather than human actions, probably drove the Balearic mountain goat humans arrived on the islands, declined sharply 4,000–5,000 the gut as a satiety signal to the (Myotragus balearicus) extinct. about 5,000 years ago. Some years ago because of a drier brain. When it is injected into This small goat, unique researchers have proposed that climate. This is likely to have humans, however, it causes to Spain’s Balearic Islands in disease or hunting by humans contributed greatly to the nausea and ruins the taste of the western Mediterranean, killed off the goats. goats’ extinction. food. Sergei Zolotukhin at disappeared soon after Frido Welker and Barbara Quat. Res. http://doi.org/p6b the University of Florida in Gravendeel of the Naturalis (2013) Gainesville and his colleagues Biodiversity Center in Leiden, sprayed PYY into the mouths the Netherlands, and their NEUROSCIENCE of mice and found that colleagues analysed plant although the animals stopped DNA found in the goats’ Satiety signal eating, as expected, they did fossilized faeces (pictured). from the mouth not become nauseous. The results suggest that the PYY in saliva seems to use goats were dependent on A human hormone might be a different signalling pathway Buxus balearica, a local species a potent treatment for obesity, from gut PYY to tell the brain of shrub. Further analysis but only if it is taken orally. when it is time to stop eating. indicated that the shrub’s The peptide hormone PYY Targeting molecules in this abundance on the islands is made primarily by cells in pathway with oral PYY or BIODIVERSITY CENTER ALINE NIEMAN/NATURALIS 440 | NATURE | VOL 503 | 28 NOVEMBER 2013 © 2013 Macmillan Publishers Limited. All rights reserved.

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