Tag Archives: Mers

One-way camel trade is keeping another coronavirus at bay, but it could still spark the next pandemic

Not to make anyone feel uneasy after this whole pandemic thing, but a new study says there’s another viral threat looming on the horizon.

Dromedary with a traditional, colorful saddle. Image via Wikimedia.

An international team of researchers is drawing attention to the fact that the Middle East respiratory syndrome (MERS-CoV), could mutate to become a global problem quite easily. While MERS has caused issues in the past and was highly lethal, it didn’t seem to be able to jump from one human to another, which limited its impact.

However, such an ability could be only a few mutations away for the virus. One subfamily of the virus is already able to infect humans, but luckily, it is still isolated from the main group. However, if these two were to come into contact, MERS could start the next pandemic.

Just one unlucky break

Pandemics, or the plagues of yore, usually start from zoonoses. These aren’t noses that like zoos at all. Rather, they’re pathogens that specialize in infecting animals but evolved to also infect human beings, at one point or another. Historically speaking, livestock is the main source of zoonoses, and the reason plagues used to ravage medieval Europe, where people and animals used to live in tight proximity with poor hygiene. Another element that makes zoonoses so dangerous is that, being a ‘new’ pathogen to humans, virtually nobody has any natural defenses against them.

SARS-CoV-2 was also a zoonosis, most likely originating from bats. The speed and ferocity with which the virus spread across the world, and the devastating effects it had on patients, are tragic reminders of just how dangerous such pathogens can become. But it’s not the only virus out there, not by far. Its big break, so to speak, what set it apart from other animal-borne viruses, was that it evolved the ability to infect a human cell — probably by accident.

MERS-CoV, a virus first seen in 2012 in Saudi Arabia, also has the potential to follow in its footsteps, according to a new study. During its initial outbreak, MERS killed around 40% of the patients it infected. However, it’s unlucky break was that it couldn’t pass from one person to another. Analyses at the time showed that virtually all cases of ¬†infection originated from dromedaries (camels). These animals, in turn, likely got it from bats.

Despite its lethality, the MERS outbreak remained a footnote of history, as it remained quite small in scope. Testing since then also seems to indicate that the danger is passing, as around 80% of the dromedaries tested so far — 70% of which live in Africa — have antibodies against the virus in their blood.

But, in a bid to find out why this virus didn’t infect many more people — especially curious considering how many dromedaries there are around, and how often people in Africa and Saudi Arabia interact with them — an international team of researchers took samples of the virus from multiple sites across the Middle East and Africa. Their goal was to identify and isolate individual strains (‘variants’) of the virus.

Those from Africa and the Middle East were separated into different clades, and were then compared from a genetic standpoint, and under lab conditions, using cultures of human lung cells. To their surprise, they found that African clades wouldn’t readily infect human cells. Those in the Arabian clade, however, would.

It all comes down to differences in the amino acids each clade uses in a particular protein — the S, or ‘spike’ protein. The team showed that African clade variants engineered to have the same amino acids in this protein as the Arabian clade had a much easier time infecting human cells.

One possible explanation for the difference between these two clades is that dromedary trade is “virtually one-way”, from Africa to the Middle East. In essence, this means that changes in the Arabian clade can’t percolate back into the African one, even if African clades do come into contact with Arabian ones. If the trade was to be reversed, however, or if a carrier animal makes its way back to Africa, the local population of viruses could become highly infectious to humans, sparking a new and deadly pandemic.

The paper “Phenotypic and genetic characterization of MERS coronaviruses from Africa to understand their zoonotic potential” has been published in the journal Proceedings of the National Academy of Sciences.

PDK plastic.

This infinitely-recyclable plastic might help us finally clean up landfills and oceans

New research from the U.S. Department of Energy (DOE) has designed a type of plastic that can be recycled any number of times without any loss of performance.

Plastic bottles.

Image via Pixabay.

The DOE’s Lawrence Berkeley National Laboratory (Berkeley Lab) has produced a new kind of polymer that, akin to a LEGO playset, can be broken down and reassembled into a different shape, texture, and color without impairing its quality. The new material is called ‘poly(diketoenamine)’, or PDK.

Plastic with a twist

“Most plastics were never made to be recycled,” said lead author Peter Christensen, a postdoctoral researcher at Berkeley Lab’s Molecular Foundry. “But we have discovered a new way to assemble plastics that takes recycling into consideration from a molecular perspective.”

The most recyclable plastic today, PET — poly(ethylene terephthalate) — is only recycled at a rate of around 20-30%. The rest winds up in incinerators, landfills, or oceans to be burned, releasing CO2, or left to clog the Earth for a few centuries until it decomposes.

Plastics are basically long chains of carbon-based molecules (‘mers’) tied together to form polymers (‘many mers’). Their structure makes them very stable chemically, meaning they won’t rust, rot or dissolve where other materials would. In order to tailor them to particular uses, manufacturers also mix in chemical additives to improve certain properties. Fillers, for example, make a plastic tough, while plasticizers are mixed in to make it flexible. These additives are chemically-bound to individual mers, and they hold on tight. So they’re virtually impossible to remove even as plastics get processed in recycling plants. Plastics with different chemical compositions get mixed together, ground into bits, and melted during the recycling process. It’s impossible to predict the properties of the resulting material before it’s actually produced.

This tendency of recycled plastics to inherit unknown additives has prevented plastics from becoming a “circular” material — one whose original building blocks (mers) can be recovered for reuse for as long as possible, or “upcycled” to make a new, higher quality product.

PDK plastic.

Unlike conventional plastics, the monomers of PDK plastic could be recovered and freed from any compounded additives simply by dunking the material in a highly acidic solution.
Image credits Peter Christensen et al., (2019), Nat.Comms / Berkeley Lab

Christensen was part of a multidisciplinary team led by Brett Helms, a staff scientist in Berkeley Lab’s Molecular Foundry, which worked to develop a plastic that won’t have this problem.

“Circular plastics and plastics upcycling are grand challenges,” Christensen adds. “We’ve already seen the impact of plastic waste leaking into our aquatic ecosystems, and this trend is likely to be exacerbated by the increasing amounts of plastics being manufactured and the downstream pressure it places on our municipal recycling infrastructure.”

“With PDKs, the immutable bonds of conventional plastics are replaced with reversible bonds that allow the plastic to be recycled more effectively,” Helms explains.

The monomers that make PDK can be separated from any additives by simply dunking the plastic into a highly-acidic solution. The acid breaks the bonds between the monomers and the additives. This property was first discovered as Christensen was applying various acids to glassware used to make PDK adhesives, and noticed that the adhesive had changed. Christensen further analyzed the plastic with an NMR (nuclear magnetic resonance) spectroscopy instrument and found the original monomers.

Subsequent research at the Molecular Foundry showed that the acid breaks down PDK polymers into monomers while also separating them from the additive molecules. The team also showed that recovered PDK monomers can be re-cast into polymers, and that the recycled polymers don’t inherit any feature of the original material. The plastic could also be upcycled through the use of additives, such as plastifiers. The researchers believe that their new plastic could be a good alternative to many nonrecyclable plastics in use today.

“We’re at a critical point where we need to think about the infrastructure needed to modernize recycling facilities for future waste sorting and processing,” said Helms. “If these facilities were designed to recycle or upcycle PDK and related plastics, then we would be able to more effectively divert plastic from landfills and the oceans.”

“This is an exciting time to start thinking about how to design both materials and recycling facilities to enable circular plastics,” said Helms.

The researchers next plan to develop PDK plastics with a wide range of thermal and mechanical properties to use in textiles, 3D printing, and foams. They’re also looking to incorporate more plant-based compounds and other sustainable materials into the PDK plastic

The paper “Closed-loop recycling of plastics enabled by dynamic covalent diketoenamine bonds” has been published in the journal Nature Chemistry.