Research Highlights

Our pick of the latest scientific literature

  • Volume 548
  • Issue 7666

Cancer

T cells can predict lung-cancer recurrence

Variety of immune cells might indicate number of recent mutations in a tumour.

The variety of proteins on immune cells within a lung tumour can predict whether the cancer will come back after surgery. 

Immune cells called T cells recognize and fight cancer using surface proteins called T-cell receptors (TCRs). Each receptor identifies a specific protein on the surface of cancer cells. Jianjun Zhang at the MD Anderson Cancer Center in Houston, Texas, and his colleagues took samples from 11 people with lung cancer and sequenced TCR genes in multiple locations within individual tumours. They found that different regions contained different types of TCR. Tumours targeted by a wider variety of these receptors were more likely to recur after surgery. 

The researchers suspect that these cancers contain a greater variety of recent genetic mutations, making them more difficult for the immune system to recognize and destroy.

Invasive squirrels and parakeets are thriving in some parts of Europe.

Invasive parakeets and squirrels are thriving in some parts of Europe. Georgette Douwma/NPL

Conservation biology

Nature reserves shield native species from invaders

Climate change drives invasions but protected areas can favour locals.

Europe’s native animals and plants can be protected from invasive species by well-designed conservation areas.

Belinda Gallardo at the Pyrenean Institute of Ecology in Zaragoza, Spain, and her team investigated the current and future stomping grounds of 86 of Europe’s most invasive species, including the grey squirrel (Sciurus carolinensis) and the rose-ringed parakeet (Psittacula krameri). They found that just one-quarter of European sites protected during the past century have been settled by any of these intruders. In addition, invasive species were rarer in older, more remote nature reserves than in recently designated or more-accessible reserves. 

The authors also modelled how the invaders’ distribution might change under projected global warming. They found the abundance of invaders will be 11–18% lower inside protected areas than outside them, despite certain species expanding their ranges by more than 20%. 

Before jaws become bone, cichlid fish are moulding their shape through exercise.

Before jaws become bone, cichlid fish are moulding their shape through exercise. Craig Albertson

Developmental biology

Baby fish that work their mouths more grow bigger jaws

Cichlid fish bones show the importance of behavioural factors in development.

Baby cichlid fish vigorously work their mouths even before bone is deposited on their cartilaginous lower jaw. Yinan Hu at Boston College in Massachusetts and Craig Albertson at the University of Massachusetts, Amherst, thought this gaping might influence bone development. They performed surgery on a cichlid species known to gape frequently (Labeotropheus fuelleborni) to modify the stresses this behaviour placed on growing bone, and restricted the water and space available to a slow-gaping species (Maylandia zebra), which leads them to gape more.

A jawbone called the retroarticular process (RA) was longer in animals that gaped more, compared with controls, whereas this bone was shorter in fish that had undergone surgery. This shift was linked to changes in expression of the ptch1 gene, which is known to regulate RA length.

The clear differences driven by this behaviour show the importance of physiological mechanisms in variation between animals.

Zoology

Cold snap drives lizard change

An extreme winter drove shift in gene expression in southern US population.

An extremely cold spell in the southeastern United States in the winter of 2013–14 drove remarkably rapid change in local lizard populations.

Shane Campbell-Staton of the University of Illinois at Urbana–Champaign and his colleagues compared green anole lizards (Anolis carolinensis) collected before and after this event at five sites, from Brownsville in the far south of Texas to Hodgen, Oklahoma, further north. The southernmost survivors of the winter showed significantly higher cold tolerance than individuals sampled from the same location a year earlier. Gene expression in these animals had also shifted to be closer to that of more northerly lizards, which tend to experience colder weather.

Extreme weather can have drastic effects on local populations and drive physical and genetic changes, the authors say.

McMurdo Dry Valleys receive very little precipitation, but still support life.

McMurdo Dry Valleys receive very little precipitation, but still support life. Colin Harris/era-images/Alamy

Climate change

Freak flood sees Antarctic desert flourish

Ecosystem invigorated by a deluge of glacial meltwater.

A rare flood of glacial meltwater in the largest ice-free area of Antarctica caused long-lasting changes to the local ecosystem. 

The McMurdo Dry Valleys have been a cold desert for thousands of years, and are home to cyanobacterial mats that live in streams and at lake margins. Michael Gooseff at the University of Colorado Boulder and his colleagues trawled through reams of data, looking for physical and biological changes that occurred in the region before and after warm weather triggered a flood in 2002.

For at least a decade before the flood, local summer cooling had coincided with steady declines in populations of both cyanobacteria and bacteria-eating soil nematodes.

In the decade after the flood, when temperatures stabilized, populations of cyanobacteria increased. Although fragments of the cyanobacterial mats were swept away in the faster currents, they also benefited from increased water and nutrient availability. 

Materials science

Sound switches material from insulator to semiconductor

Force-activated polymer ‘unzips’ into conductive configuration when exposed to ultrasound.

Scientists have designed a polymer that can rearrange its molecular structure in response to force, altering properties including colour and conductivity.

Conjugated polymers contain alternating single and double bonds that create continuous ‘π bonds’, which allow delocalized electrons to move freely. This conductivity can be greatly increased when impurities are introduced into the polymers, making them useful in electronics.

Yan Xia and his colleagues at Stanford University in California designed an insulating polymer containing fused four-membered rings in a ladder-like arrangement. When this non-conducting and colourless polymer is exposed to ultrasound, it experiences a force that ‘unzips’ the ladder to create a molecule with a backbone of alternating single and double bonds, irreversibly forming the conjugated polymer polyacetylene, which is semiconducting and dark blue in colour. 

The Spallation Neutron Source at Oak Ridge National Laboratory, Tennessee.

The Spallation Neutron Source at Oak Ridge National Laboratory, Tennessee, where the experiment took place, produces neutrinos as well as neutrons. Genevieve Martin/ORNL/US DOE

Particle physics

Neutrinos seen scattering off atomic nuclei

Researchers commandeer deep basement to watch for flashes from interactions.

Physicists have detected elusive and near-massless particles called neutrinos from their collisions with atomic nuclei, the first time the particles have been seen in this manner.

Neutrinos interact with individual particles so rarely that detecting a significant number of events usually requires carefully watching several tonnes of material for many months. Theorists predicted 43 years ago that neutrinos should interact more frequently with atomic nuclei than with other particles. But the tiny recoil of a nucleus in this process — known as coherent elastic neutrino–nucleus scattering — would be hard to distinguish from background noise.

Now Juan Collar at the University of Chicago in Illinois and his colleagues have observed this scattering at the Spallation Neutron Source facility at Oak Ridge National Laboratory, Tennessee, using a neutrino detector shielded by around 20 metres of steel, concrete and gravel. This allowed them to detect the tiny flashes of light emitted when neutrinos scattered off atomic nuclei in a 14.6-kilogram crystal of sodium-doped caesium iodide.

Studying this interaction could help physicists better understand neutrinos, say the authors.

Chimps are the only species besides humans in which two key indicators of Alzheimer’s have been found together.

Chimps are the only species besides humans in which two key indicators of Alzheimer’s have been found together. Getty

Neuroscience

Alzheimer’s indicators seen in chimps

Lesions found in four preserved brains suggest disease may not be exclusive to humans.

Chimpanzees can develop brain characteristics associated with Alzheimer’s disease as they age.

Humans with Alzheimer’s show multiple indicators of this disease, including ‘plaques’ of a protein called amyloid-β and ‘tangles’ of a protein called tau. But apart from one chimp, which died after a stroke, no non-human animal is known to have displayed both signs at the same time.

Melissa Edler at Northeast Ohio Medical University, Rootstown, and her colleagues analysed the preserved brains of 20 chimps aged between 37 and 62. They found that four of the brains contained both plaques and tangles in regions, such as the hippocampus, that are damaged in humans with Alzheimer’s. All 20 brains contained ‘pre-tangles’ — a form of tau that sometimes turns into a tangle — and several had blood vessels containing amyloid-β. Older chimps had greater volumes of plaque in their brains.

Immunology

Chronic fatigue syndrome leaves an inflammatory fingerprint

Levels of specific immune-system proteins correlate with severe disease symptoms.

Levels of 17 immune-system proteins seem to correlate with the severity of symptoms experienced by people with chronic fatigue syndrome (CFS), also called myalgic encephalomyelitis (ME).

Mark Davis at Stanford University School of Medicine in California and his colleagues searched for markers of inflammation in people with CFS, who often experience flu-like symptoms. The authors measured levels of dozens of immune-system proteins called cytokines in blood samples from 192 patients with CFS and compared them with those from 392 healthy controls. Overall, levels were broadly similar in both groups. However, when the researchers split the cases of CFS into mild, moderate and severe, they found that 17 cytokines, including pro-inflammatory proteins such as interleukin-4 and leptin, tracked the severity of the disease. 

The authors suggest that this variation between people with severe and milder states of the disease may explain why some earlier studies failed to distinguish patients from healthy people.

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