CBD and Pregnancy

Cannabidiol, more commonly known as CBD, is everywhere. There’s CBD tea, CBD face cream, CBD soap, even CBD dog treats—each promising to soothe anything from frayed nerves to blotchy skin. Now, researchers at the University of Minnesota’s Department of Animal Science and College of Veterinary Medicine are looking at whether the use of this non-psychoactive compound of cannabis has an impact on developing fetuses.

Researchers gave pregnant mice daily doses of CBD, which were scaled comparably to what an adult could purchase over the counter and use. They continued these doses throughout lactation until the pups were weaned. The pups were then taken off CBD and followed through adulthood in a study of CBD’s potential effects on behavior and molecular impacts.

The findings were significant and could potentially lead to future safety recommendations about CBD’s effect on developing brains. Researchers discovered that the impact of CBD exposure in utero continued into adulthood. It caused increased anxiety for adult female mice, although it also seemed to improve some memory functions. CBD-linked gene pathways were also associated with neurological disorders, including autism spectrum disorder, substance abuse disorder, and epilepsy.

“The effects we observed on memory and anxiety were in 12-week-old mouse offspring, a time that approximates human young adulthood, and is cause for concern,” said study coauthor Nicole Wanner, a postdoctoral fellow in the College of Veterinary Medicine. “DNA methylation marks in the brain are largely set during fetal development, and the presence of CBD during that process appears to direct certain permanent changes.”

This study appeared in the January 2021 issue of the journal Clinical Epigenetics.

Dinosaur Growth Spurts

Tyrannosaurus Rex dinosaurs were huge, often weighing in around 6,000 pounds. Scientists have understood for some time that these dinosaurs got massive during teenage growth spurts. However, researchers weren’t sure about the growth patterns of all large bipedal dinosaurs. An international team of researchers, which includes U of M Earth and Environmental Sciences Professor Peter Makovicky, is now answering that question. The hope is that the findings will shed light on the growth patterns of living birds that evolved from these dinosaurs.

The researchers looked at carnivorous dinosaurs from different times in the Mesozoic Era to see if those growth spurts held steady through generations.

By analyzing growth rings in a variety of dinosaur bones—including both a new species of giant carcharodontosaurid that was discovered and excavated by Makovicky in Argentina, as well as the famous T. Rex SUE in Chicago’s Field Museum— researchers discovered that growth patterns depended on a dinosaur’s family. T. Rex and their cousins had rapid adolescent growth spurts, gaining as much as 35-45 pounds per week. But another group of apex predators, allosauroid carnivores, grew slowly.

Makovicky and his colleagues plan to use the samples from this study for further research to understand why dinosaurs grew the way they did.

This research was originally published in the November 25, 2020 edition of Proceedings of the Royal Academy B.

Grazers and Pollution

The burning of fossil fuels and widespread use of fertilizers in agriculture has caused an increase in phosphorus and nitrogen, nutrients that boost the growth of plant life in grasslands and other ecosystems. But while the idea of more green life may sound like a good thing, excess grasses can actually be harmful to the environment because they lead to increased fire risks, loss of native species, and invasions of non-native species.

An international team of researchers that includes U of M Biological Sciences Professor Elizabeth Borer found that wild herbivores—including zebras, reindeer, and guanacos—can eat some of that excess plant life. Their study examined 58 locations on six continents and also looked at whether or not humans introduced domesticated grazers, such as cattle and sheep, onto the lands.

“Our goal is to measure the [result] of two of the most important impacts humans have had on the Earth’s ecosystems—increasing supplies of limiting nutrients, such as nitrogen and phosphorus, and changing the density of grazing animals,” says Borer. “By building a collaborative network of scientists, we have been able to conduct globally relevant research, generating new insights across continents.”

Their findings show that while wild grazing animals can offset some of the negative impacts of excess nutrients, they cannot graze as much plant growth as is needed to control unintentional nutrient pollution. Researchers say more study is needed to determine whether or not introducing domesticated grazers can improve the health of grassland ecosystems.

Originally published in the November 27, 2020 issue of Nature Communications.