Making the most of muscle oxygen

Animals have evolved a variety of ways to get oxygen under extreme conditions.

Oxygen is vital for life, and animals have developed various ways to ensure they can access it under extreme conditions — deep under water, at high altitude or in times of stress. Three papers published today in Science examine the ways that different animals achieve this feat, and how their unique abilities evolved. Read more in Nature.

Gut microbe may fight obesity and diabetes

Bacterium helps to regulate metabolism in mice.

The gut is home to innumerable different bacteria — a complex ecosystem that has an active role in a variety of bodily functions. In a study published this week in Proceedings of the National Academy of Sciences, a team of researchers finds that in mice, just one of those bacterial species plays a major part in controlling obesity and metabolic disorders such as type 2 diabetes.

The bacterium, Akkermansia muciniphila, digests mucus and makes up 3–5% of the microbes in a healthy mammalian gut. But the intestines of obese humans and mice, and those with type 2 diabetes, have much lower levels. A team led by Patrice Cani, who studies the interaction between gut bacteria and metabolism at the Catholic University of Louvain in Belgium, decided to investigate the link. Read more in Nature.

Seafood diet killing Arctic foxes on Russian island



Mercury pollution in marine animals may be behind a population crash.

An isolated population of Arctic foxes that dines only on marine animals seems to be slowly succumbing to mercury poisoning.

The foxes on Mednyi Island — one of Russia’s Commander Islands in the Bering Sea — are a subspecies of Arctic fox (Vulpes lagopus) that may have remained isolated for thousands of years. They were once numerous enough to support a small yet thriving group of fur hunters. After humans abandoned the settlement in the 1970s, the fox population began to crash, falling from more than 1,000 animals to fewer than 100 individuals today. Read more in Nature.

The single life

Sequencing DNA from individual cells is changing the way that researchers think of humans as a whole.

All Nicholas Navin needed was one cell — the issue was how to get it. It was 2010, and the postdoctoral fellow at Cold Spring Harbor Laboratory in New York was exploring the genetic changes that drive breast cancer. Most of the cancer-genome studies before then had ground up bits of tumour tissue and sequenced the DNA en masse, giving a consensus picture of the cancer’s genome. But Navin wanted to work out the sequence from individual cells to see how they had mutated and diverged as the cancer grew.

He ran into trouble almost immediately. Read more in Nature.