Category: General

By Clare Wilson

A new kind of malaria vaccine involves injecting people with the malaria parasite, then a few days later giving them a medicine that kills the pathogens. The approach has shown promising results in an early-stage trial.

Malaria, an infectious disease spread by mosquitoes, is one of the world’s biggest public health problems. It is particularly deadly for young children in Africa.

There is already a vaccine available, called Mosquirix, which works by injecting people with a molecule found on the surface of the parasite. But its efficacy wanes over time, falling to about 5 per cent after seven years.

Some groups are working on an improved Mosquirix-like vaccine, which produced positive results in April. But Patrick Duffy at the US National Institutes of Health his colleagues wondered about an alternative approach: injecting people with the whole parasite, then quickly giving a malaria medicine to stop them becoming ill.

They tried two different antimalarial drugs different doses of the parasite in a small “human challenge” study, in which people are vaccinated then three months later deliberately exposed to the malaria parasite to see if they develop the illness.

When the antimalarial pyrimethamine a high vaccine dose of parasite was used, seven out of eight people were protected against getting sick, if the same strain of parasite was used in the vaccine as for the challenge. If a different strain was used – a tougher test – seven out of nine people were protected. Another antimalarial drug called chloroquine protected six out of six people against a different-strain challenge.

These high efficacy figures don’t necessarily mean this approach would work better than Mosquirix in real life. “But it’s a level of protection that hasn’t been seen before [in challenge trials],” says Duffy.

The main drawback of the new strategy is that if people fail to take the antimalarial drug after being vaccinated, they would be likely to develop malaria. To avoid this, a larger trial has begun in Mali in which people are given pyrimethamine at the same time as they are vaccinated.

Journal reference: Nature, DOI: 10.1038/s41586-021-03684-z

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By Krista Charles

There is a new way to learn about ancient insects with the discovery that we can find fossilised beetles inside prehistoric animal droppings.

Martin Qvarnström at Uppsala University in Sweden his colleagues made the discovery by scanning 230-million-year-old fossilised droppings – or coprolites – using a technique called synchrotron microtomography.

“It works a bit like a CT scanner in the hospital, but with a much stronger energy, so we’re able to see small density contrasts within fossils,” says Qvarnström. “It’s like [the coprolites] are doing a part of the fieldwork for us by collecting the insects.”

A large number of beetle fragments along with a few nearly whole beetles were preserved three-dimensionally in the coprolites.

The beetles – the first to be described from ancient dung – belong to a new species, which the researchers have named Triamyxa coprolithica. It was probably semiaquatic had a convex body shape, says Qvarnström. “Boat shaped almost. Very small cute.”

“To get fossilised remains of this quality, researchers have relied in the past on finding them in amber (fossilised tree resin),” says Jesus Lozano-Fernandez at the Institute of Evolutionary Biology in Barcelona, Spain. “The novelty here is the possibility of looking at what is inside of the opaque fossilised poo.”

The earliest amber deposits formed about 140 million years ago early in the Cretaceous period, meaning we can’t rely on amber to learn about beetle evolution before that.

These coprolites allow us to learn about this ecological relationships in an earlier period called the Triassic.

The droppings containing T. coprolithica probably came from Silesaurus opolensis, a reptilian dinosaur relative which ate these beetles in large numbers.

“It gives a unique glimpse into at least a portion of the diet enjoyed by an early reptilian sister to the dinosaurs,” says Michael Engel at the University of Kansas. “Today, some semiaquatic beetles can be found in exceptionally high numbers on algae at seeps other water sources, suggesting that perhaps a similar ecology in these ancient beetles may have afforded a locally abundant source of food.”

Journal reference: Current Biology, DOI: 10.1016/j.cub.2021.05.015

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By Leah Crane

The smallest white dwarf star ever found is about the same size as Earth’s moon, but more massive than the sun. It appears to be shrinking, which could lead to a colossal explosion.

Ilaria Caiazzo at the California Institute of Technology her colleagues discovered this star, called ZTF J190132.9+145808.7, using the Zwicky Transient Facility in California. They then performed additional observations with other telescopes to confirm its properties.

The researchers found that it rotates extraordinarily quickly, spinning once every 6.9 minutes. The magnetic field strength at its surface ranges between 600 900 megagauss – more than 1 billion times stronger than Earth’s magnetic field.

The star, which is about 130 light years from Earth, has a radius of about 2140 kilometres, only 400 kilometres bigger than the moon. But it also has a mass about 1.3 times that of the sun, close to the limit for how massive white dwarfs can become. While most white dwarfs form from single stars at the ends of their lives, this one’s extreme mass indicates that it may be the end result of a merger of two progenitor white dwarfs.

“If [the two progenitor white dwarfs are] both massive, then the final outcome is an explosion, a supernova… but if they are two not particularly massive white dwarfs, then the system can survive create another white dwarf, a very peculiar one,” said Caiazzo in a press conference. “This one is really at that limit – it just avoided explosion.”

Because of the extreme pressure at its core, the researchers say that a strange atomic process may take place there that turns protons into neutrons, allowing it to become even more compact.

“It’s not only the smallest white dwarf ever found, it’s also shrinking,” said Caiazzo. “If this continues, it might collapse.” That collapse could result in either an extraordinarily dense neutron star or an explosion in the next few hundred million years. So the smallest white dwarf may not have permanently avoided exploding after all.

Journal reference: Nature, DOI: 10.1038/s41586-021-03615-y

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By Krista Charles

There is a new way to learn about ancient insects with the discovery that we can find fossilised beetles inside prehistoric animal droppings.

Martin Qvarnström at Uppsala University in Sweden his colleagues made the discovery by scanning 230-million-year-old fossilised droppings – or coprolites – using a technique called synchrotron microtomography.

“It works a bit like a CT scanner in the hospital, but with a much stronger energy, so we’re able to see small density contrasts within fossils,” says Qvarnström. “It’s like [the coprolites] are doing a part of the fieldwork for us by collecting the insects.”

A large number of beetle fragments along with a few nearly whole beetles were preserved three-dimensionally in the coprolites.

The beetles – the first to be described from ancient dung – belong to a new species, which the researchers have named Triamyxa coprolithica. It was probably semiaquatic had a convex body shape, says Qvarnström. “Boat shaped almost. Very small cute.”

“To get fossilised remains of this quality, researchers have relied in the past on finding them in amber (fossilised tree resin),” says Jesus Lozano-Fernandez at the Institute of Evolutionary Biology in Barcelona, Spain. “The novelty here is the possibility of looking at what is inside of the opaque fossilised poo.”

The earliest amber deposits formed about 140 million years ago early in the Cretaceous period, meaning we can’t rely on amber to learn about beetle evolution before that.

These coprolites allow us to learn about this ecological relationships in an earlier period called the Triassic.

The droppings containing T. coprolithica probably came from Silesaurus opolensis, a reptilian dinosaur relative which ate these beetles in large numbers.

“It gives a unique glimpse into at least a portion of the diet enjoyed by an early reptilian sister to the dinosaurs,” says Michael Engel at the University of Kansas. “Today, some semiaquatic beetles can be found in exceptionally high numbers on algae at seeps other water sources, suggesting that perhaps a similar ecology in these ancient beetles may have afforded a locally abundant source of food.”

Journal reference: Current Biology, DOI: 10.1016/j.cub.2021.05.015

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By Michael Le Page

NUMEROUS studies show that covid-19 often affects the brain, having a profound influence on people’s consciousness, cognition behaviour – possibly even their risk of dementia later in life.

“Mercifully, those affected are a minority of those infected,” says Benedict Michael at the University of Liverpool in the UK, “but those affected are severely affected.”

In addition, given the number of people who have been infected by the coronavirus, the impact of cognitive complications may be large could have substantial effects on health systems.

How often does covid-19 affect the brain?

Very often. Paul Harrison at the …