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Mitochondrial DNA & Alzheimer's
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0:00
Thanks to Linode Cloud Computing for supporting this episode of SciShow. You can go to linode.com/scishow to learn more and get a $100 60-day credit on a new Linode account. [♪ INTRO] When you hear the word “mitochondria”, you’re probably thinking, “powerhouse of the cell,” right?. But that’s a little bit sad! While mitochondria do provide energy to cells, there’s more to them than that. Mitochondria have their own genome that’s totally separate from the nuclear genome we usually talk about.
0:29
And mutations in that mitochondrial DNA can cause diseases in the same way mutations in nuclear DNA can. And now, one US-based research group thinks those bean-shaped little generators could be hiding the key to one of the thorniest diseases of our time. They published a study this week in the journal Molecular Psychiatry that links mutations in an often-overlooked type of gene to an increased risk of Alzheimer’s. The gene codes for a microprotein called SHMOOSE
0:57
that’s involved in energy metabolism in the brain. Yes, we literally asked and that’s what it’s called. Microproteins are relative newcomers in the world of biology research. We didn’t even know they existed until 1990. In part that’s because they tend to be small, smaller than the size cutoff scientists traditionally used when searching genomes for the bits that code for proteins. But their size isn’t where they get their micro name.
1:20
Instead, they’re called microproteins because of their functional similarity to another tiny molecule: microRNA. Both seem to have similar functions in altering the way bigger molecules in the cell do their jobs. Microproteins glom onto bigger proteins and change how they work, so they’re named after a class of RNA that does something similar with other RNA. And SHMOOSE, the microprotein in this study, seems to hang out in the inner membrane
1:45
of the mitochondria of neurons, altering energy metabolism in the brain. While microproteins can occur in the nuclear genome too, this one is mitochondria-centric. The study found that higher levels of SHMOOSE in the cerebrospinal fluid correlate with some of the biological features of Alzheimer’s disease. And they were able to use databases of brain scans of people with Alzheimer’s to determine that a mutation in the gene that codes for SHMOOSE
2:09
was associated with a 20%-50% increased risk for Alzheimer’s. That finding could be huge if more research supports it, because most of the other genetic risk factors we’ve discovered so far increase risk by less than 10%. If SHMOOSE turns out to be actively helping people’s brains hold off Alzheimer’s, that makes it a very interesting target for new treatments. One of the advantages of microproteins being so small is they can potentially be administered by injection.
2:36
So the idea would be that if a person has mutated SHMOOSE, you could give them the lower risk version to treat symptoms of cognitive decline. But that’s still a long way off. It’s early days for this research. In the meantime, SHMOOSE represents a great opportunity to learn more about Alzheimer’s, as well as microproteins, how they work, and the role they play in diseases in general. And of course, diseases don’t just affect humans.
3:00
The global banana industry has been been operating under the looming threat of a potential disease apocalypse for decades. Now, plant diseases happen all the time, and some of them can be devastating, but bananas are particularly vulnerable. That’s because most of the bananas that we eat are clones. And one thing that science fiction often conveniently leaves out in stories about clones is that when every member of a population is genetically identical,
3:24
they’re also identically susceptible to disease. There are no mutations that might make some individuals harder to infect which in turn can slow disease spread or help them withstand the plant pandemic. And this isn’t just fearmongering. It’s happened before. In the mid-1950s, a fungal infection called Panama disease swept through global banana crops, essentially wiping out what had been the dominant type of banana, the Gros Michel.
3:48
After that, growers turned to the Cavendish banana, which resists Panama disease, saving us from living in a world without smoothies. But now, a new strain of Panama disease seems to have worked out the trick to infecting the Cavendish. And it could have huge implications for the global banana supply, because we don’t currently have another kind of banana waiting in the wings. But this week, researchers in Colombia and The Netherlands announced a new strategy that may make Cavendish
4:14
resistant to the current Panama disease strain: Tropical Race 4, or TR4 for short. They essentially used the original strain of Panama disease, which the Cavendish still resists, to inoculate the plants against TR4. Dunking banana plants in a bath with the original strain, and then into a bath with TR4, made their response to TR4 infection less severe. While that’s exciting news for the future of bananas, this method of inoculating plants against disease is pretty limited in the real world.
4:43
You can’t really be dunking entire fields of banana trees in fungus water. And a lot of countries have laws in place that make it illegal to bring the fungus into the country where it could be applied to the trees. Which is understandable. But what this could do is provide a form of induced resistance to TR4 that we can study, and use that information to create a sort of banana vaccine. Really, the best solution would be to have genetically distinct bananas,
5:08
but since a commercially viable substitute isn’t available right now, making the beloved Cavendish more resistant to Panama disease is the best we can do. After all, baking banana bread helped a lot of us get through one pandemic. So, the least we can do is make sure the bananas get through theirs. And many of us spent most of that pandemic on the computer, probably using the cloud. Which is where this video’s sponsor, Linode, comes in.
5:31
Linode is a Linux based cloud service provider, so they help you do things like backup your website, run analytics, and add personalized touches to your platform. And one of the things we love most about Linode is that they are a values-based company. They could offer one expensive package that charges more for a lot of tools that you don’t need, but they don’t. They let you pay for only what you’re using. They could keep all of their code and tips for how to implement their tools private,
5:56
but they don’t. Linode keeps their tools open source and sets you up with video tutorials and 24/7 award-winning customer support 365 days of the year. You can see from all of the resources that Linode has created and curated on their website, that the user really is their priority and that their values are baked into every stage of use. To experience it for yourself, you can click the link in the description or head to linode.com/scishow.
6:20
That link will give you a $100 60-day credit on a new Linode account. Thank you for watching! [♪ OUTRO]
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