Reviews & Analysis

This Perspective reviews the evidence for and against the existence of a fetal microbiome and concludes that detected microbial signals are most likely the result of contamination, suggesting that the ‘sterile womb’ hypothesis is correct.

Snippets from Nature’s past.

A trio of tracers has debunked a long-held model of the origins of spring water on Mount Fuji, revealing interactions between shallow and deep aquifer layers, and providing a fresh approach for probing mountain groundwater flow.

The variation in the mass of newly born stars has been debated for decades. A star-count analysis now reveals that the initial mass of stars varies with their levels of metal elements, and that populations of stars born earlier in the Universe’s history contain fewer low-mass stars than do younger populations.

Immune cells called T cells were activated in mice and transferred to new mice; the process was repeated several times. The T-cell population derived from the original mice continued to respond to the same immune trigger after ten years — which is about four times the lifespan of a mouse.

The intrinsic structure of a material called a chiral superconductor enhances the separation of charge carriers, transforming an electric current in a way that could change the future of memory storage at low temperatures.

A phenomenon known as unconventional superconductivity allows electric current to flow without resistance at unusually high temperatures, but the necessary pairing of charge carriers is poorly understood in modern physics. Using an optical microscope, an experimental demonstration of such a pairing has been achieved in a simple system.

The neurotransmitter dopamine has well-established roles in reward-driven behaviours, such as searching for food. The discovery that it also shapes spontaneous behaviour reveals parallels between these two phenomena.

Air temperatures at the Greenland ice sheet have been reconstructed with unprecedented quality from an array of ice cores. The analysis shows that modern temperatures are 1.5 °C warmer than those of the twentieth century, and that this warming has been accompanied by increased run-off of Greenland meltwater.

In egg cells, the ribosomes — the machinery responsible for protein synthesis — are stored in a dormant state that is released later in the developing embryo. An evolutionarily conserved set of proteins has been shown to bind to ribosomes in the egg cells of vertebrates, stabilizing the ribosomes and suppressing their activity.

Heatwaves are increasing in frequency, duration and intensity because of climate change. Projections indicate that if global warming is left unchecked, many animal species will experience almost-permanent extreme-heat conditions, and such weather events will present a major threat to biodiversity.

Organic electrochemical transistors could be better than conventional inorganic devices for certain uses, but have been held back by performance issues. The solution could be to build up these organic transistors like a sandwich.

A review of current river ecosystem metabolism research quantifies the organic and inorganic carbon flux from land to global rivers and demonstrates that the carbon balance can be influenced by a changing world.

Snippets from Nature’s past.

Regions of the human genome that evolved rapidly after the separation between hominins and chimpanzees have now been charted. They contain genomic elements that are unique to humans and are linked to neurodevelopment and disease.

Daily rhythms affect many aspects of mammalian biology. A discovery in mice that the activity of a key type of immune cell is shaped by such rhythms might have implications for clinical efforts to tackle cancer.

T cells of the immune system develop through a lineage-commitment step followed by two checkpoints. The finding that the first checkpoint is needed to complete commitment offers a fresh perspective on T-cell development.

An analysis of the publication records of academic editors shows that one-quarter of them publish 10% of their own papers in the journals they edit and reveals that fewer than 10% of editors-in-chief are women.

A computational resource can identify candidate protein targets for almost all members of a major class of kinase enzyme in humans, with implications for understanding cell signalling in health and disease.

Our understanding of the origin of birds took a major step forward in 1998, thanks to the reported discovery of a remarkable fossil that unveiled the existence of feathered dinosaurs. Fossil publications that year caused a sensation.