Rachel Baxter, Author at ��è��Ƶ

Gas-filled black balloons create eerie floating worlds

Rachel Baxter — Wed, 16 Aug 2017 18:00:00 +0000

THESE black balloons show just how easily scientific principles can be transformed into art.

To create his work, Lithuanian artist Tadao Cern tied pairs of balloons together and filled them with gases of different densities. The ones floating at the top contain helium and the lower ones air. Each pair is sealed in a glass tank filled with a mixture of helium and air. The relative densities of the gases inside the balloons and inside the tanks allow the balloons to float, one above the other, seemingly fixed in place. The effect is strangely disconcerting.

Next Cern went supersized, making his own giant balloons from PVC that stretched up to 3 metres in diameter. Below, you can see some of his smaller home-made ones, each 1.2 metres across and filled with helium and heavier sulphur hexafluoride.

Cern says he wants the balloons to create a sense of playfulness, while also creating a sense of temporality since they will eventually burst.

“When you get into a room filled with hundreds of them floating in the middle of the room, it feels like you’re in a virtual computer simulation,” he says.

Artist
Tadao Cern

This article appeared in print under the headline “Floating world”

Goldfish go months without oxygen by making alcohol inside cells

Rachel Baxter — Fri, 11 Aug 2017 14:23:17 +0000

Swimming under the influence?

Christian Guy/Getty

Goldfish and their wild crucian carp relatives can survive for five months without breathing oxygen – and now we know how. The fish have evolved a set of enzymes that, when oxygen levels drop, ultimately helps convert carbohydrates into alcohol that can then be released through the gills.

For most animals – including humans – a lack of oxygen can be fatal within minutes. We can metabolise carbohydrates without oxygen, but the process generates toxic lactic acid that quickly builds up in our bodies.

On the face of it, this should pose a big problem for crucian carp. They live in ponds and lakes in northern Europe and Asia that freeze over in winter, so the fish have to survive for months without oxygen until the ice melts in spring.

But the carp – and their close relative the goldfish – have developed a workaround. When they metabolise carbohydrates anaerobically, the end product is not lactic acid but alcohol, which is easier to remove from their bodies.

“The adaptation is very rare among animals,” says at the University of Liverpool in the UK.

Berenbrink is a member of a team led by at the University of Oslo, Norway, that probed the carps’ biology to work out how they achieve the feat.

They discovered that the fish have their own specialised alcohol-production system. This comprises a modification of a set of the enzymes that channel energy-rich carbohydrates into mitochondria, the energy-producing parts of a cell. During their evolution, the fish gained a second set of the enzymes, which helps turn the metabolic products into alcohol when oxygen levels drop. The enzymes act in essentially the same way as brewer’s yeast.

“Usually, other species die long before the decrease in oxygen availability is even a problem for the crucian carp,” says Fagernes. “By using this method, the fish gets rid of the dangerous end products.”

Oxygen-free living

“This shows how important it is to understand simple mechanisms for surviving anoxia,” says at the University of Düsseldorf in Germany.

The study suggests this adaptation evolved 8 million years ago in the common ancestor of carp and goldfish, through a process known as whole-genome duplication. This is when an organism ends up by chance with an extra set of its genes, which can then be repurposed to take on new functions.

By making alcohol, crucian carp and goldfish can survive where no other fish can, meaning they can avoid predators or competitors. But their adaptation does mean that the fish spend most of the winter with blood alcohol levels of roughly 55 milligrams per 100 millilitres – which Berenbrink points out exceeds the drink-driving limit in some northern European countries.

Perhaps understandably, then, the fish are a bit slower than normal, says Fagernes.

Journal reference: Scientific Reports, DOI:

Type 1 diabetes may be halted by experimental immunotherapy

Rachel Baxter — Wed, 09 Aug 2017 18:00:43 +0000

Immunotherapy might help treat diabetes in future

Tom Merton/Getty

An immunotherapy approach for treating type 1 diabetes has been found to be safe for the first time, and seems to stop the condition from getting worse. Immunotherapies aim to modulate a person’s immune system, usually to relieve autoimmune conditions such as multiple sclerosis, rheumatoid arthritis or lupus. Type 1 diabetes is also an autoimmune disorder, in which the immune system’s T-cells mistakenly attack the pancreas’s insulin-producing beta cells. But no immunotherapy had proven safe for treating the condition – let alone stopped it in its tracks. Preliminary results from a small trial now suggest that peptide immunotherapy may do just that. The therapy involves injecting a person’s blood with short segments of proinsulin, a molecule produced by beta cells that is then turned into insulin. These fragments train attacking T-cells to recognise them as harmless and thus to stop attacking beta cells that make proinsulin. The treatment was given to 21 people diagnosed with type 1 diabetes in the past 100 days, while another eight people were given a saline placebo. Both groups received injections every few weeks or so for six months.

Safe and stable

By 12 months after the start of the study, the placebo group had needed to increase their injected insulin doses by an average of 50 per cent. But those who received the immunotherapy remained stable, with no need to increase their insulin doses and no signs of accelerated beta cell destruction. No adverse reactions were seen. “We’re looking at a drug that could be usable in five to 10 years, if everything goes well,” says from King’s College London, who worked on the project. Ideally, the drug would be given to children who start developing the condition, and possibly to individuals with a high genetic risk for type 1 diabetes. “The fact that this small study, designed to assess safety, suggests there may be a beneficial outcome is exciting, as we desperately need safe immune interventions that can prevent the decline of the patient’s own insulin secretion in type 1 diabetes,” says at the University of Exeter. The incidence of type 1 diabetes in Europe has been rising by about 4 per cent each year, particularly in children and teenagers, although it is unclear why. “It’s something to do with our modern lifestyle, but there are 20 or so theories at least,” says Peakman. Journal reference: Science Translational Medicine, DOI: Read more: How clean is too clean? The truth about hygiene and your health

Ancient skull belonged to a cousin of the ape common ancestor

Rachel Baxter — Wed, 09 Aug 2017 17:00:59 +0000

Meet the ancestor: new extinct ape species Nyanzapithecus alesi

Fred Spoor

A newly discovered fossil ape skull is providing clues about the common ancestor of all living apes, including our own species. The fossil – small enough to fit comfortably in one hand – belongs to an infant, and is the most complete extinct ape skull in the fossil record so far.

We now know a large amount about the evolution of the human line since it split from the chimp lineage about 7 million years ago, but the earlier stages of ape evolution – particularly the split between all living apes – are still hazy. The fossil skull throws light on that period of ape evolution.

Why is there only one species of human?

Found by fossil hunter John Ekusi in the Napudet area of northern Kenya, the fossil – nicknamed Alesi – is 13 million years old. It is the first relatively complete ape skull from the period between 14 and 10 million years ago.

The researchers used sensitive 3D X-ray imaging to look inside the skull, and check out the brain cavity, inner ears and the ape’s yet to emerge adult teeth.

The skull resembles a baby gibbon’s. “There are numerous fossil apes, monkeys, and even more primitive fossil primates that look a bit like gibbons,” explains of the City University of New York, a member of the team that analysed the fossil. “Gibbon-like features probably evolved numerous times during primate evolution.”

The fossil’s adult teeth were larger than those of similar species, so the team thinks the skull belongs to a new species – labelled Nyanzapithecus alesi. The name “alesi” comes from the Turkana word “ales” meaning ancestor.

Go ape: bony ear tubes are dead giveaway

Isaiah Nengo

“Nyanzapithecus��represents a group of fossil primates that were relatively poorly known in terms of their overall anatomy,” says Gilbert. “There were open questions as to whether or not they were even apes.”

The new study links Nyanzapithecus to apes, because N. alesi clearly has well-developed bony ear tubes – an important ape feature. N. alesi and its close relatives probably evolved some time just before the common ancestor of all living apes. We are most closely related to the great apes – chimpanzees, bonobos, orangutans and gorillas.

“It provides a tremendous amount of information on how these primitive apes developed in early childhood,” says from the University of Toronto in Canada.

“The finding tells us that human origins are deeply rooted in Africa,” says lead researcher of Stony Brook University, New York, and De Anza College in Cupertino, California. “Not only did the human lineage evolve in Africa, but also the group Hominoidea, in which humans and apes belong, also evolved in Africa.”

Nature

Penguin tail feathers reveal secrets of where they swim for food

Rachel Baxter — Tue, 08 Aug 2017 23:01:01 +0000

Where do they go when we’re not looking?

M. Timothy O'Keefe/Alamy Stock Photo

A technique from forensic science could revolutionise the tracking of marine species such as penguins. It has been used to uncover exactly where more than 100 of the birds swim in search of food, even though only half that number were fitted with tracking devices. “Understanding the patterns of migration for wide-ranging marine animals is critical to their conservation,” says at Louisiana State University, who led the research while at the Woods Hole Oceanographic Institution in Massachusetts. Polito and his colleagues focused on chinstrap and Adélie penguins from Livingston Island and King George Island off the coast of the Antarctic mainland. These species are known as “brush-tailed” penguins for their stiff, 40-centimetre-long tail feathers. Polito and his colleagues attached tags to 52 adult penguins to track their locations as they swam in search of food. When the penguins returned, the tags were recovered, along with a tail feather from each. Tail feathers were also taken from 60 untagged penguins. Using a , the researchers identified unique chemical signatures in the feathers. The signatures were imprinted from essential amino acids in phytoplankton – tiny plant-like organisms – that the penguins eat. The researchers were able to use the information from the tags to identify the chemical signatures in tail feathers associated with particular regions of the ocean that the penguins visited. They then compared the tail feathers of the untagged penguins for similarities to work out where they had travelled too.

Wider scale

“The real benefit to this approach is that when used in combination with direct tracking, it can greatly expand the number of individuals examined,” says Polito. This means it should be possible to look at migration trends on scales that would be challenging through direct tracking alone, he adds. “For practitioners in the field, this would be really useful,” says at the University of Southampton, UK. “The idea of using a combination of tags and chemicals and then harvesting a bunch of feathers is really helpful, especially in inaccessible and remote places.” Polito was surprised to find that most of the chinstrap penguins left the productive waters of the Scotia Sea and travelled west into the Pacific sector of the Southern Ocean. “Some of these westward-migrating chinstrap penguins travelled up to a whopping 3900 kilometres away from their breeding colony,” he says. Polito says the technique could also be used to track other animals, such as whales, seals and turtles, providing a vital tool to help in conservation efforts. Journal reference: Biology Letters, DOI:

Tackling resistant malaria may fuel antimicrobial resistance

Rachel Baxter — Mon, 07 Aug 2017 21:00:06 +0000

Diagnostic tests have slashed the number of prescriptions for antimalarial drugs

Global Warming Images /REX/Shutterstock

Rapid tests that can tell if a person has malaria or not have led to a sharp drop in unnecessary malaria drug prescriptions, but may also have prompted a rise in the use of antibiotics.

Rapid diagnostic tests can quickly tell if a person with a fever may have malaria. These tests have become more available since the World Health Organization implemented a diagnosis-before-treatment policy in 91 countries in Africa – part of efforts to reduce the over-use of antimalarial drugs, which has been driving the evolution of drug-resistant malaria.

Since this policy was introduced, global testing for malaria has risen from 45 million tests in 2008 to 314 million in 2014. Now an analysis of 500,000 medical visits in Tanzania, Ghana, Uganda, Nigeria, Cameroon and Afghanistan that took place between 2007 and 2013 has found that diagnostic tests have slashed the number of prescriptions for antimalarial drugs. While between 20 to 100 per cent of people with a fever were given antimalarial drugs in clinics that don’t yet use diagnostic tests, this fell to between 8 and 69 per cent in clinics that do.

While this is good news for preventing the spread of resistant malaria from south east Asia into these regions, the use of diagnostic tests seems to have had an unfortunate side effect – increasing the number of people prescribed antibiotics.

Drug swap

In most areas studied, antibiotics were given to between 40 to 80 per cent of people who had a fever but did not test positive for malaria. Non-malarial fevers can be treated with medicines like paracetamol and by drinking a lot of water, but less than 25 per cent of patients were given this option.

This is a concern, because increasing the unnecessary use of antibiotics could further exacerbate the international crisis in antimicrobial resistance.

“There is a very real and present risk of antibiotic resistance emerging very rapidly when these medicines are used at scale,” says , of the London School of Hygiene and Tropical Medicine, who worked on the analysis. “We can’t just focus on getting doctors and patients to swap from one drug to another – we need to look at how we provide care and meet the needs of patients beyond provision of medicines.”

Journal reference: American Journal of Tropical Medicine and Hygiene, DOI: 10.4269/ajtmh.16-0955

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It took 2000 years to make seed for America’s famous ‘corn belt’

Rachel Baxter — Thu, 03 Aug 2017 18:00:02 +0000

Corn: picky about its growing conditions

Robert Hsnks/EyeEm Getty

Maize first arrived in the lowlands of the south-west US 4000 years ago – but it was another 2000 years before farmers living in the region’s highlands began growing it routinely. Now we think we know why: it took millennia to select varieties of the crop that flowered early. This is a necessary trait to make the most of the shorter growing season in the cooler, higher altitude conditions. In the face of rapid global warming, however, we will probably have to use genetic engineering to help maize adapt quickly enough to cope with today’s challenging growing conditions. In the 1970s, archaeologists unearthed 15 1900-year-old maize or corn cobs at a site in Utah called Turkey Pen Shelter that, with an elevation of 1800 metres, is at a relatively high altitude. Now, at Cornell University, New York, and the Max Planck Institute for Developmental Biology in Tübingen, Germany, and her colleagues have extracted and sequenced DNA from the ancient cobs. By comparing the genetic sequences with more than 2500 modern lines of maize from a global collection, they were able to predict the flowering times of the ancient maize. The ancient maize seemed to flower about a week earlier than modern warm desert-adapted forms, putting it broadly in line with the flowering times of maize grown today in higher altitude, cooler parts of the south-west US. This is the first time that this kind of complex trait – flowering time – has been successfully reconstructed from ancient samples and then validated using modern plants.

Flowering time

“The idea of predicting flowering time of ancient maize is original and new,” says , an evolutionary biologist at the University of Paris-Saclay. “Adaptation of temperate corn in the US helped a lot in its subsequent introduction to Europe.” If maize originally adapted to temperature over 2000 years, it may struggle to adapt to modern climate change – although modern maize is more variable than its ancient relatives, says Swarts. “I think we should be encouraged by the diversity we find within maize,” she says. “Sufficient diversity is present in maize to counter the changing climate and because of this it is probable that traditional breeding approaches should be effective.” There is one important distinction, though: the current pace of climate change is unusually fast. “The difference this time is that we don’t have thousands of years to assemble the correct variants in a given individual,” says Swarts. “Climate is changing at such a rapid rate that I think to maintain or increase food production in the years to come we will need to use all of the tools that we have.” That will probably include genetic modification using techniques such as CRISPR genome editing, says Swarts. The archaeological samples also showed that high-carotenoid yellow maize – popcorn – initially evolved in the south-west US. Maize is eaten on every continent except Antarctica and is important in sustaining the world’s growing population.

Science

CRISPR skin grafts could replace insulin injections for diabetes

Rachel Baxter — Thu, 03 Aug 2017 16:00:53 +0000

Testing the blood sugar

GARO/PHANIE/REX/Shutterstock

Genetically modified skin grafts have protected mice from developing diabetes, suggesting the technique may help people with the condition.

The method makes use of the gene that encodes a hormone called glucagon-like peptide-1 (GLP-1). This hormone decreases appetite and helps regulate blood sugar levels by triggering the release of insulin, which removes excess glucose from the blood.

However, the hormone only works for a short period. To tackle this, at the University of Chicago, Illinois, and his colleagues used CRISPR gene-editing to alter the GLP-1 gene so it would make a hormone that is active in the blood for longer. They then inserted this gene into mouse skin cells in a dish, and developed them into skin grafts that could be transplanted onto mice, letting the modified hormone get into their blood.

Skin therapy

The grafts were given to mice that were fed a high-fat diet. These mice went on to gain around half as much weight as those not given grafts, and developed less resistance to insulin. High insulin resistance is a common precursor to type 2 diabetes.

The researchers gained similar results when they made the grafts out of human skin and transplanted them onto hairless mice.

The edited gene was found to make GLP-1 hormones that were stable and active for three months, suggesting that grafts could be a desirable alternative to daily insulin injections.

It will be relatively easy to translate this into a treatment for people, because skin grafts have been used to treat burn wounds for many years, says Wu. He suggests that grafts with different edited genes may be useful for treating other types of disease too.

“I do predict that gene and cell therapies will ultimately replace repeated injections for the treatment of chronic diseases,” says at the University of British Columbia in Vancouver, Canada.

Journal reference: Cell Stem Cell, DOI:

Rachel Baxter, Author at ��è����Ƶ