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Viruses are among humanity's greatest threats and it seems like they're always one step ahead of us. But this week, biologists say that they've discovered a new weapon we can use against some of our most nefarious virus enemies - and it comes from our friends the plants. Get the full story from Hank in today's SciShow news.

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Viruses really suck.  They are among humanity's greatest threats and it seems like they're always one step ahead of us.  This week, biologists say that they've discovered a new weapon that we can use against some of our most nefarious virus enemies and it comes from our friends, the plants.

Intro music

 Viruses


Viruses are responsible for some of the world's deadliest diseases like Ebola, rabies, and Marburg fever.  In fact, the five most fatal infectious diseases on Earth are all born by the same order of virus, called Mononegavirales.  And unlike bacteria, we don't have many effective treatments for them.

While we've got antibiotics to beat bacteria, for viruses we generally have to use our own immune systems to get at it with vaccines, and they keep mutating faster than we can invent new ones.  And research has shown that viruses also develop resistant to anti-viral treatments, much like bacteria can become resistant to antibiotics.

So, what's humanity to do?

 Thwart the Copy


We may be close to an answer.  On Thursday, microbiologists and chemists at Boston University said that they've discovered a molecule that may defeat some of the worst known viruses by interfering with the process they use to copy themselves, called transcription.

Now, the scumbags in this gang are all called non-segmented negative strand RNA, or NNS RNA, viruses, and unlike other viruses, they can't be copied directly.  Once they infect the cell, they need to create a template, sort of a genetic reverse image called an antigenome.

This template is then used over and over to make marauding hordes of viruses that take over our bodies.  But to create the antigenome, these viruses need a specific enzyme called RDRP.  So the Boston team set out to find molecules that could block RDRP, thus stopping them in their tracks.

The scientists started with healthy host cells, pre-treating them with a whole variety of chemical compounds before exposing them to two of the meanest known viruses in the world, Ebola and VSV, which causes foot-and-mouth disease.

After testing over 2,000 different compounds, the team discovered that one group of molecules successfully blocked the virus's transcription.  They're called indoline alkaloids, a big and really diverse group of chemicals that are responsible for many of the medicinal properties found in plants, including some of the anesthetics, sedative, and hallucinogenic effects.

In cells treated with these compounds, viral replication was 99.9% lower than in control cells and the cells showed significantly less death over all.

In other words, these alkaloids totally body slammed the viruses while causing no harm to the infected cells.  So, does that mean that we have a cure on our hands?

 A Cure?


We-e-e-ell, we're not there yet.  For one thing, the team doesn't know why these molecules worked so well, they suspected it has something to do with the alkaloids' shape, which is similar among all of the affected molecules.  This shape could be preventing the RDRP from doing its job or it might be messing with other factors inside the host cell the viruses need for transcription.

Also, while the molecules wipe the floor with both of the NNS viruses while they were tested on another class of viruses, called segmented negative strand RNA viruses, the molecules didn't have the same effect.

So this is certainly a promising step for treating some of the world's deadly viruses but it's not going to treat them all, like HIV for example.

 Plant Source


And finally I should point out the study, published in the Journal of Chemistry and Biology, doesn't say what kind of plants these compounds were taken from, so don't go grazing in your backyard to ward off the flu or anything.

Nonetheless, this is a huge discovery with big potential, once we figure out exactly how these compounds work, the team said the structure of the alkaloid could be synthesized and improved upon to kick even more virus behind.

Knowing how to make a molecule with anti-viral properties like this can lead to drugs that treat a broad spectrum of viruses, much like how antibiotics treat bacteria.  And to those future drug makers, I think I speak for all humanity when I say, "Shut up and take my money!"

Thank you for watching this episode of SciShow.  If you have any questions or ideas we're on Facebook and Twitter and in the comments below.  And if you want to keep up to date on the latest breaking science news you can go to youtube.com/scishow and subscribe.