Antimicrobials Inspired by Animals

Antimicrobials Inspired by Animals

The animal kingdom is diverse, fascinating,
and often downright amazing. Many people – including scientists – might
even call it inspirational. Animals are currently inspiring a new generation
of robots, but what about medicine? We’re constantly facing new threats from
viruses and antibiotic-resistant bacteria. So scientists are learning from animals’
natural disease-fighting abilities to make new antimicrobial drugs and materials. —– One of these antimicrobials was first found
in 1993, when researchers observed that dogfish sharks never seemed to get any sort of infection,
even in unsterilized tanks. The scientists isolated a substance from the
shark tissues that they named. And soon they were able to make it synthetically
in the lab. More recent studies have shown that squalamine
has the power to make human cells better at resisting viral infections. Viruses have to use various tricks to get
past our cell membranes and infect our cells — like by recruiting help from our very own
proteins! One of these proteins is called Rac1,
which normally sits on the negatively-charged inside of the cell membrane, bound there by
the protein’s positive charge. Rac1 helps regulate lots of different processes
— including what gets in and out of the cell, kind of like a bouncer. So, viruses can co-opt it to sneak inside
our cells. But squalamine can put a stop to such treachery. Squalamine is also positively charged, and
certain cells have transporters to let it through their membranes. Then, squalamine latches onto the negatively-charged
inside of the membrane, and displaces Rac1 and other proteins for a little while, which
keeps the virus from coming in the cell. This means the immune system can kill off
the exposed virus. And after a couple hours, any remaining squalamine
is filtered right back out of the bloodstream by the liver. So squalamine may be what’s keeping the
dogfish shark virus-free. And with a little more research, maybe it can protect us from
some dangerous viral infections too. We’re also learning about killing microbes
from cicadas: those noisy, red-eyed bugs that —– spend most of their lives underground before
coming out to scream for a few weeks, have sex, and then die. As annoying as they are, in 2012, researchers
discovered that one species, the Clanger cicada, had an awesome antimicrobial power. Their wings are coated in tiny spikes that
burst bacteria on contact! Rather than straight-up popping the bacteria
like a bubble, these nanopillars actually stretch the life out of them — pulling
the cell surfaces thinner and thinner until they rupture. This piqued the interest of a research group
from Bristol, England, who wanted to see if these nanopillars could have medical applications. See, medical implants like hip replacements
and pacemakers are often built with titanium. This metal is strong, durable and relatively
light, but not anti bacterial — so bacteria tend to colonize the surface, which could
lead to dangerous infections. And if standard antibiotics can’t kill the
bacteria, the implant may need to be surgically replaced. But how can we make a metal surface with deadly
spikes that kill bacteria without harming our own cells? Well, in this case, size matters. The researchers created these titanium dioxide
nanowires, which were a similar size to the cicada nanopillars and lethal to bacterial
cells. Human cells, on the other hand, – which
are about ten times larger – slid over the slightly bumpy surface unharmed. So their calls may be annoying, but cicada
wings can teach us a lot about medicine. And so can molecules called antimicrobial
peptides or AMPs — which are just short chains —– of amino acids that many animals use as part
of their defense strategies. Researchers have found potent AMPs in some
pretty weird places… think cockroach brains and alligator blood! Peptides come in many shapes and sizes, but
the best-known ones form a helix – kind of like a stretched Slinky – with an overall
/positive/ charge. They’re attracted to the negative surface
charge on bacterial cell membranes, and punch through the cell surface to make these gaping
holes. Which isn’t so great for the bacteria, and
they’re usually dead in seconds. Meanwhile our cells – which are mostly uncharged
on the outside – are left unscathed. It would be amazing if we could use these
natural AMPs in medicine, but it’s currently difficult — some of them are toxic, while
others get quickly destroyed by our bodies. So scientists are trying to bioengineer them
to be safer and more effective. For example, they tweaked an AMP that actually
came from humans, making it shorter and more strongly charged. This new peptide successfully killed antibiotic-resistant
MRSA bacteria when used as a nasal spray. So, who knows what some other modified AMPs
could do for us? In a few years, we could be keeping harmful
microbes at bay with science inspired by shark livers, cicada wings, locust brains and who-knows-what-else
nature has to offer. Thanks for watching this episode of SciShow,
brought to you by our patrons on Patreon. And don’t forget to go to
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About the Author: John Markowski


  1. Yeah this is why I love science. We have people with huge knowledge probing the most funamental aspects of the world around us, from cells, chemicals, atoms and smaller things and they learn amazing new things that vastly improve our loves and would seem like magic to people from past eras. It looks at everything and sees wonder, and creates wonder. Go science!

  2. How do we stop animals from being inspired by robots? I don't want my cat to be inspired to make a Terminator. I'm not letting my cat watch old episodes of Robot Wars or Mythbusters until I get a good answer.

  3. Cicadas are not annoying! They come out of the ground once every 17 YEARS, and they are truly amazing. Do not disrespect them.

  4. As the wise Ian Malcolm once said, "Life, uhhh… finds a way." Just as superbugs are becoming resistant to more and more antibiotics, new pathogens will evolve resistances to these new medicines.
    If we strike them down, they will become more powerful than we could possibly imagine.

  5. wow interesting material, glad that one super annoying woman host wasn't the one delivering it or i would have learned nothing

  6. I did not realize charges affect bacteria or know about those awesome spikes on cicada wings!

  7. Scishow needs to do a video about Dmitry Belyev. Spread this around if you agree.(maybe it will help get their attention) If you have no idea who he is look him up. Its really interesting!

  8. This new technology could end nearly all diseases. Or it could push the microbes' evolution and make then more resistant to these defences. That might condemn the animal species that inspired it in the beginning, and make them more vulnerable to disease.

  9. Why do you yawn when you are tired? I learned in my anatomy and physiology class that yawning brings blood to your brain, but why would you do it if you are sleepy

  10. "Those noisy red-eye bugs that spend most of their lives underground before coming up to scream for a few weeks, have sex and then die."

  11. Could you do a video about why the chicken pox are so much more dangerous for adults than children?

  12. I feel like the best long term shot at defeating bacteria is just more technologies developed to increase the strength of our own immune system. Like vaccines which can be rapidly produced for every new disease and rapidly distributed to the populace.

  13. Is it bad that I sometimes think that our zeal to fight diseases might actually be bad for us? It is probably a reason for the increase in population that the earth soon can't sustain… Even if I understand that no one wants to die or watch a loved one die…

  14. guys he didnt say that animals are INSPIRED by robots

    he said that animals are INSPIRING a new generation of robots

    you just misheard him

  15. Its amazing how much science can do to make our lives better. And yet governments only fund these projects by 1-2% of the budget.

  16. Hey SciShow guys, admiring fan here. I have a video request πŸ™‚ it's a stretch but here it goes can you guys please make a video addressing how minoxidil slows hair lose down? And in the same video address how it would theoretically help guys grow beards. I thought it would be interesting, informative and getting a real scientific open would be awesome and not to mention super helpful for science loving,bearded hopeful, guys like myself :).

    Please and thank you πŸ™‚

  17. Is it me or are your videos getting more silent lately. And no, system and video volume are normal.

  18. Science used to hated gems, they want to terminated all of them.Now they want to play with virus/bacterial. gg

  19. It's unfortunate that this probably wouldn't be necessary if humans took the anti-biotic as recommended instead of just taking it until they stopped noticing symptoms of whatever they were suffering from in the first place.

  20. Cicadas are not annoying and not necessarily red eyed, there are a ton of different species with eyes ranging from brownish to greenish dark.
    Not to mention the different sounds they make.

  21. I'd rather see the surface of hip implants utilize the structure which allows the body to grow into it, rather than around it.

  22. SciShow, for the link at 0:12 you put animals inspired by robots. Now, it is really nice to know that the animals of the world have been moved by our creations, but perhaps you meant to write "robots inspired by animals".

  23. You missed that shark skin surface that doesn't let microbes stick. I think they're using it on catheters now

  24. I really hope we don't abuse these antimicrobials and then make the current extinction event even worse by making all the natural antimicrobials obsolete and endangering the animals we got them from.

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