biology, covid, evolution, medicine, Science, science news

Is a pan-coronavirus vaccine possible? Plus: sweaty humans and the barn owl of dinosaurs.

I’m aware that I’ve already broken my promise not to talk about coronavirus, so I guess it won’t hurt if I break it again, right? Anyway, you may be concerned about all this talk of variants in the news, particularly the India variant that is wreaking such havoc in Asia. There is justifiable concern that the vaccines we’ve developed may not be as effective against variants that will evolve. This, of course, is one good reason why we should aim to get as close to “zero covid” as possible: keeping the number of cases down limits the possibility of advantageous (to the virus) mutations to arise, potentially ones that we would have to develop new vaccines against, in a potentially endless cycle.

But what if we could make a global coronavirus vaccine that would not only be effective against all the different variants of covid-19, but also potentially against other deadly coronaviruses like MERS and SARS-CoV-1? This could preventially prevent the next pandemic. Researchers are already looking into this, as this interesting and thoughtful (and hopeful!) piece in Science explores. Many of these are targeting the common “spike” protein that these viruses use to infect cells, but focusing on generating antibodies against multiple different regions, particularly those that are common across different virus species and that do not vary as much. Others take the approach of trying to active T-cell responses, rather than B-cell producing antibodies, or even the old-school tried and tested means of using a combination of inactivated whole viruse to generate an immune response. It’s encouraging that scientists are already thinking ahead and trying to tackle this problem.

Why are humans so sweaty? Sorry: but yes, we are. Really sweaty. Compared to most other primates, we have 10x the density of sweat glands in our skin. This is our key way of regulating our body temperature and helping us to cool down. Unlike most other apes, we evolved on the hot, dry African savannah, and not the jungle. Not only that, but we relied heavily on the ability to run to hunt prey, particularly over long distances. All that makes for a hot hot human who needs to cool down: sweating works by evaporative cooling, in which the heat energy dissipates as the moisture on our skin vaporises.

But how did we evolve this ability? A lot of the traits that we think of as human are complex, evolving changes in multiple genes. Increasing the density of sweat glands, however, appears to have been relatively simple. This is controlled by the activity of the gene Engrailed (first discovered in fruit flies – another example of how important this model organism has been). By altering the activity of control “enhancer” elements of Engrailed in mice, researchers have demonstrated that multiple changes in the control regions of this gene have resulted in higher levels of Engrailed, and so more sweat glands. It’s a really neat piece of work that also demonstrates a key theme of evolutionary developmental biology: changes in regulatory DNA often have more profound effects than changes in the bits that actually code for proteins. There’s an accessible Science Daily article here:

Today’s amazing animal is, alas, extinct. It’s an extremely bizarre (and cute) dinosaur called the shuvuuia that had extremely good hearing and night vision, judging by analysis of fossils of its skull. Of course, birds are descended from dinosaurs (theropod dinosaurs, to be precise, which are the ones that tended to walk on two legs, like T. rex) but it’s interesting to see that some had specialised adaptations that we see in much later bird species, like barn owls. Shuvuuia is part of a group of dinosaurs called alvarezsaurids, which share a unique characteristic in common with modern birds: they can lift the upper part of their jaws in relation to their skulls. Indeed, the alvarezsaurids may be more “bird” than “dinosaur”. It may also help explain the shuvuuia’s bizarre appearance: this funny little creature not only had feathers, but long legs and tough little forearms with a single claw. Likely it hunted insects at night and used the claws to excavate prey from burrows. Original paper published in Science here, with a brief news piece here (both paywalled, alas).

Featured image

Shuvuuia deserti: artist’s impression by Victor Radermaker

biology, evolution, medicine, Science, science news

Brains, ears, tongues (and a bit of Covid)

Good news for those suffering from tinnitus, in which a persistent ringing or buzzing is heard, not caused by external sounds. Although this doesn’t seem serious (if you don’t suffer from it…) it affects a whopping 15-20% of the worldwide population, and can range from annoying to downright dibilitating. Moreover, it looks like there’s been a rising incidence during the pandemic, possibly due in some cases to long-term effects of covid infection. So it’s great to see an effective new treatment do well in clinical trials (I missed this study when it came out last October). Oddly enough, it involves electrically stimulating the tongue at the same time as sending audio pulses to the ears, calibrated for each individual patient. This is a process of medical neuromodulation, in which a targeted stimulus is used to alter nerve activity. After a 12 week course of treatment, the majority of participants in the trial reported improved symptoms for up to 12 months afterwards. The study is published in Science Translational Medicine here (paywalled).

One jab or two to protect against Covid-19? It’s a debate that’s been going back and forth; generally you will need a booster vaccine, but some of the vaccines coming through are designed to give protection with only one dose. However, if, like me, you’ve already had Covid-19, it looks like you only need one dose of the mRNA vaccines (Pfizer, Moderna) to get protection, with this triggering a robust immune response, and the second dose not making much difference (not that would hurt it you had it anyway) If you haven’t had Covid, you’d need both doses. Study published here in Science Immunology (and really one for the immunologists, as it’s quite technical).

Today’s weird and wonderful animal is the Indian Jumping Ant, which can selectively shrink and regrow its brain in response to its reproductive status (no jokes about baby brain please!). Worker ants, who do not reproduce, have larger brains, but, if the colony lacks a queen, they can shrink their brains and grow their ovaries to invest all their energy into laying eggs. The researchers found that they were fully capable of transitioning back to worker status if they artificially simulated that environment, shrinking their ovaries and regrowing their brains. Amazing! Full study published in Proceedings of the Royal Society B here.

Image Credit

“This image reveals a worker jumping ant Harpegnathos saltator murdering the queen. The queen had just torn off her own wings after a successful mating and was scouring the forest floor in search for a suitable nest site. Though this de-alated queen was ‘murdered’, a large number of her sisters successfully established nests, thus completing their life’s mission – passing on the colony’s genes.”

Kalyan Varma, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons

biology, evolution, Science, science news

Placentas as mutation landfill, and solar-powered, self-decapitating seaslugs that regrow their own bodies

Well, now I’ve got your attention with possibly the weirdest title I’ve ever given a blog post, I do have some weird and wonderful stories for you.

First up: placentas as mutation landfill. I was trying to think of a more “sciency” way to describe this, but it got too complicated. And anyway, it’s (sort of) true. We’re used to thinking of the placenta (if we think of it at all) as a lovely, nurturing organ that sits there stuck to the side of your womb when you’re pregnant, supplying all the good stuff to the developing baby and taking the waste away. Turns out that it’s not just waste in the sense of waste byproducts from metabolism. The placenta actually acts as a sort of dumping ground for genetic mutations in the early embryo. How?

Just a bit of embryology to start: the placenta isn’t part of the mother, it originates from the foetus. In the very early developing mammal embryo, at the blastocyst stage, it consists of a hollow ball of cells. In the middle of the ball is the inner cell mass, which will go onto form the actual foetus. The outer layer is the trophoblast, which implants into the lining of the uterus (womb) and forms the placenta. (Quick video of implantation here). Theoretically, they should be genetically the same. But it’s been known for a while that in 1-2% of placentas, some of the cells have a different number of chromosomes than they should. Having just one extra chromosome can cause significant problems and is frequently fatal; Down’s syndrome, in which three copies of chromosome 21 are present instead of the usual two, is one of the rare survivable conditions, for example. It’s also the case that aneuploidy – having too many or too few chromosomes – is a very common defect in human eggs, and is one the leading causes of early miscarriage. So, too, are problems with the placenta.

A new study has taken a detailed look at the genomic architecture of the placenta, and the organ is like no other human organ: it resembles something more like a patchwork of tumours, with distinct clonal populations having different mutations in them. Surprisingly, in many cases, the placenta seems to function fairly well. But why is it such a mutation-riddled mess? Interestingly, many of these mutations are associated with childhood cancers. But what’s fascinating is that in at least one case, a defect present in the fertilised egg seems to have been corrected: a “trisomic rescue”: the cells that went on to develop into the foetus had managed to revert to having just two copies of their chromsomes (correctly), but the placental cells did not. This fascinating finding seems to support the theory that the placenta is, in part, acting as a “dumping ground” for harmful mutations present in the fertilised egg: the embryo avoids them, but the placenta does not. Original study, published in Nature, can be found here. An accessible Science Daily summary can be found here.

Today’s weird and wonderful animal is the sacoglossan seaslug. Specifically, two species that are able to grow a whole new body once their head is severed, which they do deliberately to get rid of a parasite infection. It’s an extreme example of autotomy, the self-amputation of a body part (e.g. a lizard shedding its tail to avoid a predator). It’s the severed head of the seaslug that grows a new body: the cast off body dies. How does the head manage to grow a new body when the seaslug can’t digest any nutrients? Well, and this is just as cool/strange: the seaslug is able to incorporate chloroplasts, the photosynthetic machines of plants, into their own cells from the algae they eat, and use this to get energy and carbon compounds from sunlight. Incredible. Great video from the Guardian below. Original research article, with more video, published in Current Biology here.

Image credit

Elysia marginata, Rickard Zerpe, CC BY-SA 2.0 https://creativecommons.org/licenses/by-sa/2.0, via Wikimedia Commons

biology, Climate change, Environment, evolution, Science, science news

Ozone recovery, covid futures and the wolf that wasn’t a wolf at all

In today’s good news story, there has been a decline in ozone-damaging CFC (chlorofluorcarbon) emissions in China. (Paywalled, unfortunately, but the abstract is free). The ozone layer is a layer of O3 high up in the stratosphere that protects life on Earth by absorbing damaging ultraviolet light. It was realised in the late 1970s that it was being destroyed by chemicals used as refrigerants in fridges, freezers etc., leaving the infamous “hole” in the ozone layer over the Antarctic. (In practical terms, there’s been about a 4% decline in ozone levels since the 1970s, and several “holes” are seen in seasonally variable patterns, but particularly at the poles). In 1986, an international treaty, the Montreal Protocol, capped emissions at 1986 levels, and committed nations to subsequent decline. Production of emissive CFCs was phased out globally in 2011, and alternative chemicals are mandated for use. This has largely been successful, and the EPA has reported a gradual trend towards “healing” of the ozone layer.

Things did seem to take a step back in 2013, however, when atmospheric monitoring revealed CFC emissions rising, largely in eastern China, suggesting illegal production. This raised a lot of alarm amongst scientists. However, it seems that the alarm was heeded and production halted, as they are now declining again. It’s a refreshing reminder that, actually, environmental problems can be fixed where there’s international will to do so and solutions exist. Climate change, whilst far more complex, is not insoluble.

Now I know I promised no bad news, and when it comes to the big C (Covid, not cancer) there’s a saturation of excellent and not-so-good content out there. Recently, however, there’s been a lot of speculation of “what happens next” once the immediate crisis is over. Is total elimination possible, or is suppression the best we can hope for? What if mutations arise that mean it “escapes” the vaccine response? And so on. On that note, Nature has an interesting and readable feature on “Covid Futures” (free to read) based on a survey of what 100 scientists working in directly relevant fields thought would happen. In particular, this infographic is very clear and useful, and indicates that, in most outcomes, the worst case scenario is avoided.

CORONAVIRUS: HERE TO STAY. Graphic showing some of the key factors that are likely to lead to SARS-CoV-2 becoming endemic.

And finally, today’s featured fabulous animal is the dire wolf (featured image). These large predators roamed North America from around 250,000-13,000 years ago, possibly dying off due to climate change. From the many available fossil skeletons, they appeared rather similar to grey wolves – just 20% bigger. However, a DNA analysis has proved elusive, until now. This new study has revealed that they’re not really wolves at all, but in a unique lineage of canids (wolves, coyotes, foxes etc) that branched off from the others nearly 6 million years ago. What’s more, they appear to have evolved in North America: the ancestors of wolves and coyotes colonised America from Eurasia later on, and did not cross-breed with the dire wolves. It’s a fascinating glimpse into a divergent branch of the evolutionary tree. You can read a news piece here, or the full genetic analysis published in Nature here.

Image Credit

By Eden, Janine and Jim – Flickr: Dire Wolf Skeleton, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=31534986

medicine, Science, science news, Sunday Science Stories

Finally back, with a focus on good news and weird animals: today, a potential new treatment for multiple sclerosis and wombat poo.

Well, apologies for the hiatus, but it’s been a bit like that, hasn’t it? I’m still “enjoying” the challenges of pandemic working plus homeschooling/caring for a small child, so I still have no spare time. However, I have resolved to do less doomscrolling, and, in an effort to focus more on positives (and be realistic about what can be achieved), I’ve decided that this blog will concentrate on science news stories that are good news stories. These will be updated when I can, at least fortnightly again I hope – plus also weird and wonderful animals, which will be the focus of the featured images, because who doesn’t like those?

I’m going to start with vaccines. No, not coronavirus vaccines, you’re probably all experts on those by now. This is a vaccine against the autoimmune condition multiple sclerosis (MS). It is, however, based on the same principles as the Pfizer coronavirus vaccine: using mRNA to entrain the immune system. How does this work? A little background first. Every cell in your body (bar eggs and sperm) contains a complete copy of your all the genes needed to make you in your DNA-based genome. The genes code for proteins, which are both the building blocks and workers of your cells. But not all the genes are switched on at the same time in every cell. You don’t want to making digestive enzymes in your brain, or muscle tissue in your liver, right? Genes that are switched on are “transcribed” into a messenger RNA, or mRNA, sequence, which is then translated into the protein. Unlike DNA, mRNA is single-stranded (which is also why it’s so unstable and has to be stored at -70C). The mRNA-based coronavirus vaccines use this principle to inject mRNA coding for a bit of virus protein into your cells. This is then made into protein which your immune cells can recognise and make antibodies against (Moderna has some good info on mRNA technology and the basic biology behind them here).

In the case of this MS vaccine, however, it is being used to train the immune system to tolerate myelin, the nerve cell coat that is degraded in MS, rather than attack it. Your immune system has to learn not only to recognise things that are harmful, like bacteria and virus proteins, but harmless everyday things it shouldn’t worry about and learn to ignore. When this doesn’t work, you can get problems ranging from allergies (e.g. reacting to harmless pollen) or autoimmune disease, in which the immune system starts attacking the body’s own tissues. In the case of multiple sclerosis, this is the insulating coating of the nerve cells, made of myelin. The MS vaccine contains an mRNA encoding a myelin-like protein, and reduces severe disease in a mouse model. Yes, it’s just a mouse model so far, but it’s promising. mRNA vaccines look like they’re going to be an exciting new field of research, and I am going to be very interested to see if this could be applied to more autoimmune diseases. Original paper published in Science here (paywalled, alas, but you can read a Nature opinion piece here).

Todays’ wonderful animal is the wombat (featured image). These delightful marsupials can run as fast as human, dig burrows (and have backwards-facing pouches so they’re babies don’t get dirt shovelled on them) and use their backsides for defence. No, they don’t fart in your general direction; it’s made of tough cartilage that a predator has a tough time getting a bite out of. They also produce cube-shaped faeces. Apparently this is because it stops it rolling away, and wombat poo is important in marking territory and communicating with other wombats. But it’s always been a bit of a mystery as to how they do it: how do you make square poo from a tubular intestine? Via careful contraction of the walls it seems. They have “two stiff and two flexible” regions which help shape the faeces into the characteristic cube shapes. And if you’re thinking that this is a waste of research money, it would actually be quite useful to know how to do this for some manufacturing processes. The best thing about this research is that it is published a journal called Soft Matter. And a group of wombats is a wisdom of wombats, which I think we can all get behind. Not the square poo though. That’s all theirs.

MS treatment & wombats

Featured image:

Southern Hairy-nosed Wombat (Lasiorhinus latifrons). Author Stygiangloom. https://www.flickr.com/photos/stygiangloom/220992362/

Science

PSA: intermittent/suspended blog posting

I generally aim to post science stories every 2 or at least every 3 weeks on this blog, so regular readers can expect a (semi!) reliable output. However, due to the demands of now having to work from home full time but also look after a small child full time, this is currently proving near-impossible. If I get a few moments to post something exciting or interesting, I will do so, but regular blog posts are realistically not going to be happening for a little while. Apologies all!

biology, medicine, Science, Science and society, science news, Sunday Science Stories

Super-sensing dogs, crafty cuttlefish, whale migration, and please wash your hands…Sunday Science 08/03/20

Lots of clever animals in this week’s Sunday Science, with cuttlefish connoisseurs, super-sensing dogs, and whales who go the distance for a good skincare regime….plus: self-promotion in science, and how washing your hands really is the best individual tactic against coronavirus… Continue reading

biology, cancer, Environment, evolution, genetic modification, medicine, Science, science news, Sunday Science Stories

Coronavirus, albatross police, biodiversity declines, and why it’s never too late to give up smoking…Sunday Science 16/02/2020

A slightly belated Sunday Science, due to term hitting with unusual force three weeks back. More on coronavirus, CRISPR against cancer, using albatrosses to police illegal fishing, giant fossil beasties, and why it’s never too late to give up smoking.

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biology, Developmental biology, Explainer, medicine, News, Science, science news, Sunday Science Stories

Coronavirus, how stress turns your hair grey, culturing snake venom, and global human cooling…

In this week’s Sunday Science: some facts on the new coronavirus that is spreading through China (and abroad); how stress turns your hair grey; how scientists are stressed (so we’ll all go grey early); how human body temperatures are falling, and growing your own snake venom…. Continue reading

biology, Climate change, Developmental biology, evolution, medicine, Science, science fiction, science news, Sunday Science Stories

Carnivorous plants, BCG vaccine, dogs & schizophrenia and how flies land upside down: Sunday Science 12/01/2020

Welcome to the first Sunday Science of the New Year, with carnivorous plants, injecting new life into an old vaccine, reducing schizophrenia risks (by dogs), how the UK transformed its energy supply, and how flies land upside down on your kitchen ceiling… Continue reading