The Smallest Pathogen on Earth: Viroids Explained

[@d_wang9836]

Viroids sounds like a disease for viruses

[@frankschneider6156]

+[Yoshikage_Kira] Viruses aren't alive, so they can't have a "disease", just like a stone can't get ill.

[@mrexists5400]

viruses are the closest thing to the current definition of life without it being life

[@RetentiveCloud]

Or steroid'd viruses

[@MrFappington]

ObesityHitMeOnceMore they're called virophages. Like you said, they attack large viruses (Nucleocytoplasmic Large DNA Virus NCLDV).

[@wenxuanzhou5823]

+Frank Schneider Actually, they can. They have RNA which other viruses can take advantage of, so they definitely can get infected and destroyed by another virus. They're called virophages. Just like bacteria can also get infected by viruses called bacteriophages.

[@MrMysticphantom]

I expect this video to go viroid

[@narcotic702]

Stop

[@godspeed2145]

*Rolls eyes*

[@Tautolonaut]

videos go viral, I imagine still pics go viroid.

[@Scarachus]

Viroidal?

[@aidanc4719]

HA!

[@stabulouskoda834]

every time it zooms in on Michael's face I just really appreciate his hair

[@haithummohsin6273]

Yes lol but earings don't suite tbh... no offence though

[@TheConnor12500]

The incredible complexity and beauty of life never ceases to amaze me.

[@TheRogueWolf]

"Hop Stunt Viroid" sounds like a KZbin video of someone botching a pogo-stick trick.

[@doubtfulsausage]

Or a mad scientists way to make beer

[@pyro226]

Jalapeno on a stick? (Jeff Dunham)

[@EmmaR]

It's 2am and I'm watching a video about viroids

[@2intheampm512]

Emma R. This hit

[@commentsanitizer7929]

Good gal

[@stuartrussell8572]

What could be better?

[@ezachleewright2309]

I stayed up to 7:00 AM yesterday morning

[@EmmaR]

@@ezachleewright2309 Nice

[@AbbeyAnn]

I know I'm a bit late to the party but your hair looks so good 😍

[@inkedseahear]

That's a nice definition of life you got there. It would be bad if… …something simple appeared

[@anastasiacarvalho401]

My professor finished this topic in my class today. what a coincidence this is!

[@lizgichora6472]

Thank you!

[@himanisharma8507]

Best sci channel I have ever seen.

[@weshard1]

Aren't prions a smaller pathogen?

[@myky992]

Also likely depends on how you define pathogen. Possibly we are referring to live pathogens? But if something blurs the line between alive and death more than viruses, it's definitely viroids...

[@bigbenhebdomadarius6252]

Prions are proteinaceous particles, similar to viruses and viroids, but lacking a genetic component. This may be out of date, but I think prions attack animals, and viroids affect plants.

[@myky992]

I do wonder why that is. I looked quickly on the wiki for viroids and it seems none affect animals. I don't know about prions. yet we both use proteins, and we both use RNA... maybe it's the difference in immune systems? Animals drove animal viroids extinct by being supergood at eliminating them and plants did the same for plant prions? Obviously just spitballing hypothesis with no substance here :D

[@hobnails]

They absolutely are a smaller pathogen. It's probably just another "if it doesn't look like what we arbitrarily consider life, it couldn't possibly be alive!" designation denying it the spot. Prions are responsible for high-profile diseases like Kuru and mad cow disease. They are proteins that are capable of deforming other proteins into a likable shape, thus perpetuating themselves in a hospitable environment. It's theorized some of them have several sections to themselves each granting it different capacities, it may even require RNA in some function to produce most known prions, but it's a very mysterious field of research. It's a pretty clear instance of life existing in some form without DNA.

[@davidsamson1453]

Prions do not have any independent genetic material (i.e. RNA or DNA) with which to "replicate" in the way that viruses, viroids, and other pathogens do. They're more akin to a harmful chemical (like a poison) produced by another organism like snake venom (which are proteins as well), except their function is totally different.

[@aweirdpizza2249]

An episode on virusoids would be pretty interesting.

[@BrokebackBob]

Michael is rocking his hair!!

[@quinton1630]

Who suddenly has this in their recommended feed in March 2020?

[@tfsheahan2265]

Outstanding. For those of us who do not have out finger on the throbbing pulse of biology, this is a big help. Might you do an update on the other end of the topic. Virus or virus-like things that are bigger and more complex than viruses, but are not stand alone organisms?

[@anotherhappyday93]

I love it when Guy with Haircut looks like he just got a haircut

[@triplemgaming5103]

0:27 ‘It can infect potatoes’ *two seconds later* 0:35 ‘A clue to how life started on Earth’ 😂😂😂

[@nicanornunez9787]

I love scishow as much as I love scihub. Keep it up whit the good work, and thanks.

[@eyuin5716]

I initially misread the title and I thought I read "Smartest Pathogen".

[@DavidFrostbite]

Epic hair as always.

[@jamesh625]

If the viroid is circular, how does the RNA Polymerase know when to stop replicating (and join the replicated RNA into a circle)? Is there some sequence of nucleotides on the viroid that signal to the RNA Polymerase to terminate?

[@mickmickymick6927]

The Irish Potato Famine was caused by Blight by the way, a common potato and plant disease which farmers still have to manage today, they should have just mentioned the disease.

[@jebosamvasjako]

The moment when you understand the big words behind this video

[@Articulate99]

Always interesting, thank you.

[@Xoediac]

Love your hair :)

[@EpicSelenium34]

how did you get that plant cell diagram at 1:56? I can find one like it but it's labeled.

[@studioMYTH]

OOOOH THE HAIRCUT! I like it.

[@YiGzit]

This is was a good video on this topic. Liked by a biotechnologist student!

[@Alexieto]

love your hair. so how do farmers fight viroids? i mean is there a cure or is it mostly just prevent the spread of the viroid?

[@LuisAldamiz]

He sounded like there is no cure but that methodical cleaning of gardening tools (with alcohol, I guess) is a good prophyllactic measure. I doubt there is a cure, just as there are no cures for viruses in general (can treat the symptoms, maybe prevent with a vaccine, but can't kill what is not really alive).

[@evanbecraft8201]

@@LuisAldamiz careful man mentioning whether a virus is alive or not will start a nuclear war viruses, by the generally universal definition that is a major subject to debate, are not alive. Technically, destroying the structure of the virus/viroid could be considered killing it if we allow parasitic reproduction and alternative evolutionary paths to be considered a form of life. I do believe that the definition of life is not broad enough, and I also believe that anything that self replicated through processes through encoded information is in fact a living organism.

[@LuisAldamiz]

@@evanbecraft8201 - I'm aware of the debate: there's no consensus on whether viruses are alive or not. I would say they are, sorta, because they do reproduce, while rocks or other inanimate objects do not. Computer viruses are also alive, sorta. My old school definition of life was that a living being is one that "is born (check), grows (?), reproduces (check) and dies (check)". The virus only dubiously does not grow, although it does as the RNA/DNA chain does grow in numbers and accumulating the protein structure around it is a form of growth. So I'd say that viruses are alive by the primary school definition. They are not alive by Basque language usage, but trees aren't either, only animals.

[@BrentBarnard]

It would be intriguing to see an episode dedicated to counting down the oldest mountain chains on the planet. In "4 Billion Years in Under 10 Minutes," you mention that the Appalachians are far older than the Rockies. It would be interesting to see a sequential countdown of the top 5 or 10 oldest mountains/mountain chains.

[@jesusramirezromo2037]

What about Prions?

[@zed1stwizard]

Prions are infectious (agents) composed entirely of a protein material that can fold in multiple, structurally abstract ways, at least one of which is transmissible to other prion proteins, leading to disease in a manner that is comparable to the spread of viral infection. Not a life form.

[@LeoMRogers]

While you're on wikipedia, take a look at the 'pathogen' page. Being a life form isn't a prerequisite of being a pathogen, and prions are listed as pathogens.

[@TheGrandMasterPotato]

But do pathogens necessarily have to be considered living?

[@josiahklein70]

Jesus Ramirez Romo Infectious, malformed proteins.

[@zed1stwizard]

I stand corrected.

[@xWood4000]

This is cool, I would have liked to learn this in elementary school.

[@hakari_kinjiofficial]

Nice explanation

[@AlexandrKovalenko]

Adding sour cream to potatoes? Are you nuts?

[@jasonharrison25]

Looks like he's just about going to burst right out of his shirt

[@mva2997]

Newer, sexier Michael Aranda upgrade

[@sharktamer7306]

Non-notification squad where you at!

[@TRexPhilbo]

+

[@surya8891]

here

[@notlun]

fresh cut

[@mechanizedape2998]

The funny thing is, rna could not have formed in the conditions of the early earth environment. The reason is because rna uses molybdenum oxide to self assemble. Molybdenum oxide could not have exsists in the environment of the early earth. Even more interesting is that Mars did have the proper conditions for molybdenum oxide to form.

[@sharktamer7306]

The 3 dislikes are viroids.

[@pranavmahadikar2147]

sharktamer no viruses

[@conf1rmed819]

98 viroids dislike dis vid

[@imustbeames3727]

Thank you Mr. Elizondo

[@trangium]

1:10 what's Uracil?

[@theextraterrestrialsscienc7122]

And here we have it: A molecule that at the same time is a living organism, impressing.

[@LuisAldamiz]

Sorta. Biologists don't really agree on saying that viruses are "living organisms" or "life" at all. They lack self-sufficiency, they are rather weird organic chemistry that is only somewhat life-like. This would be even more clear for viroids.

[@eliscerebralrecyclingbin7812]

Cool thanks

[@RichardASalisbury1]

Very cool!

[@bigbenhebdomadarius6252]

Like the new haircut.

[@n124lp]

I don't find diseased potatoes to be narley, but the one in the picture looked gnarled. ;-)

[@SlyPearTree]

Are viroids responsible for graboids? Nice subject for a video, I never heard of viroids before, thanks.

[@mianfazlerazik3636]

Hey virus show some skin..... Ok now I am a viroid

[@jackdavids2723]

Prions are the smallest pathogens, and the most resilient

[@homemobile8362]

Thank u ❤

[@anthonybeervor2265]

This is the scariest thing I have heard since I learned about bacteriophages.

[@edi9892]

How does the viroid rna get into the target cells? Viruses need sensors and injection needles for it...

[@rkpetry]

What's the difference between "phage" (the term in use ca 1960's) and "viroid" (herein)....

[@CorbinChancellorTV]

Great video, RNA world hypothesis might make a good video

[@TheNinjutsustudent]

I know what next year's Halloween costume is going to be.

[@germimonte]

but wait, how could rna be fist, if it needs all that comlex structure from a host to replicate?

[@bonhomhongon2794]

Does anybody else feel an overwhelming sense of affection towards viroids

[@thelastcube.]

Viroids are like Yoda - small and legendary ALL HAIL HOLY VIROIDS

[@LejaLexiphanic]

Chaitanya Singh your profile pic made me think there was a hair on my screen lol

[@uranus_crunch_cake87]

I just blew on my screen....smh

[@aniekanumoren6088]

Does this count as evidence towards the RNA world hypothesis in the theory of Abiogenesis? If so, then were one step closer to figuring how life on earth came to be. So exciting!!!!

[@Art_Fox894]

Too good👍👍

[@davebashford3753]

"... when they extracted samples of [the viroid] ..." So much in one simple phrase. How do you extract a sample of anything, let alone an unknown substance?

[@ElementalAer]

Extraction of the infected plant material in solvent, and sucessive filtrations, with better and better filters, and analysis by microscopy of the samples to see if you encounter a strange body

[@davebashford3753]

@@ElementalAer Thanks

[@emilybe8652]

Very interesting

[@pigcatapult]

I somehow still wasn't expecting these guys to be even smaller than prions.

[@complex314i]

There is one detail of the RNA first hypothesis that I have never seen answered: the U to T transition. DNA is comprised of the four bases adenine, cytosine, guanine, and thymine. However, in RNA uracil is utilized in place of thymine. How was this fundamemtal base switched when life transitioned from RNA to DNA?

[@kieferfarrer4734]

so why cant we fully digest corn?

[@vishensivparsad]

How does the rna survive the environment? Shouldn't uv light and other strong stimuli destroy it

[@elgatoguapo88]

what did those ancient viroids use to replicatd themselves without the plants they use now?

[@theviniso]

How do these guys get inside plant cells?

[@ujepagaz8495]

why does he say "usually" at 1:09

[@bobbyharper8710]

Maybe this is the aliens we've been expecting

[@MsSqueashy]

Boi when did he get his hair cut

[@MC-up9nx]

And that's how the curly fry was born.

[@AvangionQ]

No biggie, just humanity drawing one step closer to discovering the origins of life ... 🔬

[@tonyhernandez331]

I thought they were trying to make a click bait video with all the circles lmao

[@robertcarlyon6076]

scishow my dad found this new remedy called Bachs pastilles and he wants our while family to try it. but I am very skeptical and I really need your help.

[@Orick9417]

what is the difference between this and a phage/prions?(ie mad cow)

[@7lllll]

since prions are famous, their relations to viroids should have been explained in this video

[@davidhickman3200]

So are viroids consideres living organisms? They're even simpler than viruses, but you did refer to them as "living fossils"

[@zzzzzzzz999zzzzzzzzz]

Hey, question: are our bones always wet? Thanks

[@FonVegen]

Looks like Theodor *served* a *vital* purpose here! Get it? Because his last name is "Diener", and this is about pathogens...

[@jerotoro2021]

Wait, are you telling me you don't put sour cream on your baked ginger?

[@TheCashewOfDeath]

So how are they different from prions?

[@ChainsawDunDeez]

Excellent... I remember reading an early 2000 science article about viruses being possibly the key to the origin of life/ RNA world... And when Viroids were mentioned and described briefly....I was thinking? Wait ? Aren't these things even simpler then viruses ?? Couldn't these be a possible key component to the origins of life/ or 'living Fossils' of 'The RNA world' (Theory)?? Glad That possibility been shared to other thinkers and learners...good job Scishow!

[@thatjillgirl]

What about prions? Do we not count them as pathogens since they are pure protein?

[@vapenation7061]

*_THE MITOCHONDRIA IS THE POWERHOUSE OF THE CELL_*

[@ManintheArmor]

We must make nanomachines from these.

[@fredriks5090]

Thumbnail made me think of another kind of virus - the red "click here to find the answer"-circles on thumbnails.

[@chrisboucher1987]

And here I thought it was a viral hemorrhoid. Phew!

[@ganeshfulkari9334]

Nice sir

[@ardaarda7472]

How small are these in nanometers?

[@dg-hughes]

I have personal knowledge of the power of the ribosome/ribozyme in the form of Creeping Charlie lawn weeds, those things are indestructible and I think grow in seconds!

[@the_tank122]

can yoh show the bloopers to sci show?

[@josephcole8102]

prions might be smaller, but they are more like cell corrosion or rust than an infection

[@junkdubious]

Are they smaller than prions?

[@pigthug]

Say it ain’t so…where’d the Apple Watch go?😜

[@spindash64]

Considering that the examples you named are all plant based, I'm assuming that Viroids don't bother animals as much? Maybe the free floating RNA is particularly bad at avoiding immune system protection or something?

[@theodorebelmont2181]

Viruses: The microscopic jellyfish

[@geopixels6886]

Okay okay. I have a real question related to this important issue. Who tops their sour cream with potatoes?