Reviews & Analysis

The mammalian testis is a rapidly evolving organ, in both structural and molecular terms. An investigation of testicular cell nuclei from 11 species has unveiled genes, cell types and evolutionary forces that underlie these changes.

Plants have immune systems that defend them against various disease-causing microbes. One virus targets plant hormone receptors to help it to infect plants. As a defence, a plant has evolved an immune receptor that mimics hormone receptors, recognizes a virus-encoded protein and triggers immune defences.

When circularly polarized light hits an array of chiral gold nanoparticles, it generates polarized electric and magnetic waves across the surface of the nanoparticles. Chiral molecules can alter these resonances, providing a highly sensitive method to determine and quantify molecular chirality, even at very low concentrations.

In the neocortex of the brain, excitatory neuronal cells that arise from the same progenitor cell express patterned combinations of clustered protocadherin proteins (cPCDHs). The pattern of cPCDHs expressed by a neuron regulates its spatial positioning and its connections with other neurons.

Ancient environmental DNA from northern Greenland opens a new chapter in genetic research, demonstrating that it is possible to track the ecology and evolution of biological communities two million years ago. The record shows an open boreal-forest ecosystem inhabited by large animals such as mastodons and reindeer.

Supplies of the crucial molecules ATP and NADPH are lacking in many human diseases, but restoring them requires tight control. Using light-powered thylakoid structures from plants to carefully deliver these molecules to the joints of arthritic mice slowed degeneration.

In an enormous study of almost 3.4 million individuals from 4 ancestries, variants of more than 2,000 genomic regions were found to be associated with tobacco smoking and alcohol use. Genetic variants that contribute to these behaviours have been identified, and the accuracy of genetic risk scores compared in diverse populations.

A widely used drug called UDCA reduces SARS-CoV-2 infection in human organoid structures, animals and human organs maintained outside the body. Individuals using UDCA for liver conditions are less likely to develop severe COVID-19 than are people who did not use it. UDCA treatment could help to protect people with suppressed immune systems and offer protectionagainst vaccine-resistant variants.

The response of cumulus clouds in trade-wind regions to warming is a large uncertainty in climate projections. Observations now indicate that the mechanism leading to the strongest cloud reductions in models does not occur in nature, suggesting that extreme sensitivity of Earth’s temperatures to climate change is less likely than previously thought.

Changes in salt-marsh areas around the world between 2000 and 2019 were quantified using satellite records, and the effects of these changes — collectively representing a slowing net global loss — on carbon emissions were estimated. Storm events were found to be key drivers of salt-marsh loss in the United States.

The electrolytic splitting of saline water is a highly desirable and sustainable method for the mass production of green hydrogen, but seawater contains many impurities that hinder the long-term stability of conventional electrolysis systems. A method for enabling the electrolysis of seawater has been developed that addresses previous side-reaction and corrosion problems.

Touch signals from the skin are carried to the brain by intermingled projections of two pathways in the spinal cord. These pathways convey distinct features of tactile stimuli, and converge differentially on brainstem neurons that direct different aspects of touch to various brain regions.

The enzyme V-ATPase pumps protons into vesicles at the synaptic connections between neuronal cells, and is crucial for neuronal communication. Observations of individual V-ATPase molecules reveal that they randomly switch between proton-pumping, rest and leaking modes, which each last for several minutes, with potential implications for neurotransmission.

Crops such as maize need nitrogen to create protein, and the yield of many modern crops relies on nitrogen fertilizers. A previously unknown gene variant found in a non-domesticated maize variety enables plants to use nitrogen more efficiently and produce more protein than their modern counterparts.

Bacteria have evolved diverse immune systems to defend themselves against viral infection. Many of these systems require specific viral triggers for activation, but these triggers and their activation mechanisms remain mostly unknown. A bacterial immune system that senses a viral structural protein enables an effective immune response against viral infection.

Simulations reveal that the annual temperature cycle in the Pacific cold-tongue region is influenced by the shape of Earth’s orbit, as well as by the planet’s axial tilt. Together, these influences drive remarkable changes in the cold tongue’s seasonality across a cycle of about 22,000 years.

The glacier in Greenland’s largest drainage basin is thinning and its flow is accelerating. Updated simulations suggest that sea-level rise will be up to fivefold higher than previously expected.

Gene expression was assessed in individual liver cells from mice that were infected with the rodent-specific form of the malaria parasite. This revealed that infections of cells in the inner zones of the lobule units that make up the liver are more likely to succeed than are infections in the outer zones.

Perovskites are promising candidates for use in next-generation light-emitting diode (LED) displays that are vivid and have high colour quality. LEDs made from particles with a perovskite nanocrystal core and an acidic shell are efficient and bright, and have a long operational half-life.

Analyses of archival imaging data from the Hubble Space Telescope in 2010 reveal multiple images of a star that exploded about 11.5 billion years ago. An image sequence starting 6 hours after the explosion shows the supernova cooling rapidly during its very early phases.