Welcome to this week’s Sunday Science, featuring a new drug approach to treating cystic fibrosis; the importance of green space for mental health; super-smelling mice; an exotic new conducting material, and unexpected ally of the red squirrel in its fight against the grey squirrel…

A novel approach to treating cystic fibrosis (CF), a genetic condition that causes serious lung and gastrointestinal issues. The problem is caused by a mutation in a gene coding for a protein that acts as a channel, regulating the flow of ions (specifically chloride and bicarbonate ions) in and out of cells. This leads to an electrolyte imbalance causing problems with, amongst other things, severe mucus build-up in the lungs, in turn leading to infections. There’s been lots of effort to try and find a cure, including investigating trying to replace the faulty protein or gene. Some exciting new research tries the novel approach of making small holes in cells to essentially replace the channel function of the protein. They use a small drug to essentially makes a new ion channel, restoring the ion transport and, importantly, the anti-bacterial defences. Original article here (paywalled).

If you had more of a specific type of brain cell, would you better at performing the task they’re specialised for? Well, probably if you had lots of extra cells made as an embryo, you’d end up with a brain that didn’t function properly. Most neurons in mammals are made before they’re born; however, there are a few specialised niches known in the adult mouse brain at least that continually generate new neurons throughout life (whether this is true of humans is controversial). But what are they for? An elegant new study carefully engineered the stem cell populations for these to divide more frequently, giving extra neurons in as normal a manner as possible. These were neurons involved in olfaction – the sense of smell. At first, it didn’t seem that they made much difference; in a simple scent discrimination task, these mice didn’t perform any better than mice with the normal number of neurons. But at a difficult task in which they had to distinguish between two very similar stimuli, they had increased sensitivity. This study immediately made me wonder whether variations in human sensitivity to certain sensory stimuli, for example the heightened sensory sensitivity seen in autism spectrum disorder, might be due to the numbers of neurons being born – although this would be before adulthood, of course. There is a simple opinion piece here.

The native red squirrel population of Britain has undergone a drastic reduction since the introduction of the invasive grey squirrel, such that the red squirrel is now largely confined to parts of Scotland. Not only do the grey squirrels compete for resources, but they act as a reservoir for the squirrelpox virus,which is usually fatal to red squirrels but not affect the greys themselves. However, an interesting new study has revealed an unusual ally of the red squirrel: the pine marten. This is another European mammal whose numbers plummeted after suffering historical persecution. As their populations begin to recover, they have a negative effect on the grey squirrels – but not the red, which benefit from increased pine marten density.

It’s been known for some time that living in dense urban environments can increase the risk of certain psychiatric disorders – but not why. A study of nearly a million people in Denmark has revealed that what is critical is not urbanisation itself, but how much green space you grow up with as a child. The authors controlled for a variety of confounding factors, and found that those with the lowest exposure to residential green space had a 55% increased risk of developing psychiatric disorders in adolescence or adulthood than those with the greatest exposure. This is a strong argument for the integration of green space in urban planning.

An interesting breakthrough in the field of topological materials. If you’ve never heard of them, neither had I (I am a biologist, not a physicist after all!). As I (barely) understand it, topology is a branch of mathematics that describes properties that can only change in discrete steps, rather than a continuous flow. It can help explain how certain materials known as topological insulators conduct electricity on their surfaces with very little resistance (like superconductors but without the need to be extremely chilled) while their interiors do not conduct current. They tend to be quite robust under different conditions too. Now, researchers have discovered the strongest topological conductor yet, in the form of thin crystal samples with a structure like a spiral staircase, almost like a DNA double helix spirals (see featured image). Also like a lot of biological molecules, they exhibit a “chirality”, or handedness (like your right or left hand are mirror images of each other), which seems to explain some of their properties. Original article published in Nature here (paywalled).

And finally, the largest Tyrannosaurus rex ever found, at an impressive 13 metres long. It’s also one of the oldest, estimated to have been in its thirties when it died, which is old for T.rex.

 

Featured image

Ilustration shows a repeated 2D patterning of a property related to electrical conductivity, known as the surface Fermi arc, in rhodium-silicon crystal samples. Credit: Hasan Lab/Princeton University via Science Daily.

Topological conductor:

https://www.sciencedaily.com/releases/2019/03/190320141014.htm

 

 

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