Name: 这种病毒不应该存在（但确实存在）（This Virus Shouldn't Exist (But it Does)）
Uploaded: 2022-04-25T09:40:16.000Z
Duration: 11 min 10 s
Description: 【看影片學英語】數萬部 YouTube 影片，搭配英漢字典即點即查，輕鬆掌握單字發音與用法，長久累積看電影不必再看字幕。

hidden in the microverse all around you there's  a merciless war being fought by the true rulers  

of this planet microorganisms amoeba protists  bacteria archaea and fungi compete for resources  

程度副詞

and space and then there are the strange horrors  that are viruses hunting everyone else not even  

alive they are the tiniest most abundant and  deadliest beings on earth killing trillions every  

day not interested in resources only in living  things to take over also we thought turns out  

there are giant viruses that blur the line between  life and death and other viruses hunting them

considerably smaller than your cells or even  bacteria viruses are nothing but a hull a tiny  

bit of genetic material and a few proteins no  metabolism no way to propel themselves no will  

or ambition they float around aimlessly and hope  to stumble upon a victim to infect and take over  

viruses are so simple that we're not sure  if they should count as living things or not  

some scientists argue viruses are alive others  think that the cells they infect are the actual  

living viruses hybrid organisms called viral  cells and the viral particles are more like seeds  

or spores and many others think viruses are just  dead material the origin of viruses is a mystery  

because how can something that needs victims  to make more of itself emerge in the first  

place there are many ideas viruses may have been  essential steps in the emergence of life or maybe  

they started out as escaped dna from cells that  became really good at making copies of themselves  

maybe they are the descendants of truly lazy  parasites that let others do all the work for  

them the current thinking is that viruses probably  emerged multiple times from different origins  

but we simply don't know for sure yet whatever the  truth is viruses are the most successful beings on  

this planet there's an estimated 10 000 billion  billion billion viruses on earth if we put them  

all next to each other they would stretch for 100  million light years 500 milky way galaxies wide  

very recently viruses became even weirder  when scientists found a completely new type  

giant viruses nicknamed gyrus not only did it  break all sorts of records but questioned many  

assumptions we had about their nature gyruses  even come with their own parasites virophages  

viruses that hunt other viruses which seemingly  makes no sense at all and since we identified the  

first one in 2003 it seems like these giants  are everywhere we look in the oceans in water  

towers in the guts of pigs and the mouths of  humans and they're even weirder than we thought  

gyruses look funny like hairy geometric  forms or mini pickles much larger than  

all viruses we knew before which explains how  they could hide in plain sight for centuries  

scientists saw them under their microscopes  and just thought they had to be bacteria  

it's like suddenly discovering there  are elephant-sized ducks everywhere  

most gyruses we've found so far hunt amoebi and  other single-celled beings when they find a victim  

they connect with it and use its natural processes  to enter the cell like all viruses their goal is  

to misappropriate the victim's infrastructure and  procreate imagine a mouse crawling into your mouth  

and using your guts and bones and  fat tissue to build a mouse factory  

the gyrus unloads its attack proteins and genetic  material and rearranges the cell from the inside  

its structural elements protein production  machinery and large amounts of mitochondria  

for energy are changed to become an actual  factory called viroplasm some gyruses even  

construct a membrane to shield them from the  cell's antiviral defenses once finished the  

viroplasm begins to assemble new gyruses using  the victim up from the inside until it's filled up  

finally the invader usually orders the cell to  self-destruct and releases new gyruses to look  

for new prey but what makes gyruses special  is not their modus operandi or their size even  

it's that they are much more complex than thought  possible for a virus your cells have around 20  

000 genes a typical bacterium has a few thousand  genes the coronavirus has around 15 hiv or the flu  

around 10. the number of genes alone is certainly  not everything the tomato for example has 35  

000 genes but generally we think of life as a  complex system so below a certain complexity level  

something may be closer to dead material  rather than a living organism but gyruses  

can have hundreds or even thousands of genes  blurring the line between living and dead things  

and it's not just the numbers that are special  but also what these genes do we used to think of  

viral genes as the simplest of instructions just  enough to overcome the defense of their victims  

and make new viruses but many gyrus genes  are completely unique basically mystery genes  

even more confusing a huge selection of their  genes that are actually hallmarks of living  

things genes that regulate nutrient intake energy  production light harvesting replication or are  

just necessary to keep cells alive some recent  studies have even suggested that some gyruses  

with very complex genomes may be able to maintain  a basic level of metabolism on their own which if  

true will shake up what we thought of viruses  even more we still don't know anything for sure  

but one idea about gyrus genes is that they might  fundamentally alter the physiology and evolution  

of their victims by integrating their own genomes  and merging with them into chimeric organisms  

or the other way around take some host genes with  them and be changed themselves for billions of  

years gyruses may have been existing alongside  and infecting cells exerting an unseen influence  

on the development of life not just as a parasite  but jerking evolution in different directions by  

mixing genes around in all directions which brings  us to another unique thing about them virophages  

the viruses hunting gyruses the concept itself is  a bit mind-boggling how can a thing that might be  

dead hunt another thing that might be dead too  let's look at one of them the viruphage sputnik  

is hunting a gyrus called mama virus that  itself is hunting amoebi sputnik is a tiny  

minimalistic virus that doesn't even have  the genes and tools to replicate itself  

what it does have is the ability to hijack the  viroplasm factories of mama viruses so virophages  

need their victim the gyrus to infect their victim  an amoeba first and then they can parasitize it  

a memovirus viroplasm infected by sputnik can only  produce very few new gyruses and among these many  

are deformed and broken unable to infect further  cells instead it makes loads of new sputnik  

viruphages other virophages are even more subtle  when they infect a viroplasm they just integrate  

their genetic code into the newly produced gyruses  like sleeper agents the next time one of these  

infiltrated gyruses successfully infects a cell  it produces mostly viruphages instead of gyruses  

gyruses are not completely defenseless  though a few years ago the world was in  

awe when scientists discovered crispr a bacterial  defense system against viruses it turns out some  

gyruses have a system that might be similar a  sort of gyrus immune system against virophages  

in turn virophages can also be used as an  antigyrus defense mechanism by living cells  

some protests have been found that integrated the  genetic code of virophages into their genome and  

kept it when the protists were infected by gyruses  they used the code to create virophages themselves  

to take over the gyrus factories in the end  the protists would still be killed by the gyrus  

infection but instead of releasing gyruses to kill  its buddies it released virophages to hunt them  

the amazing thing about everything we've told you  in this video is that we're still very much at the  

beginning it's not even been 20 years since the  discovery of gyruses and virophages there is so  

much going on in the microverse life is not an  isolated event but a ping pong game of trillions  

of organisms and viruses so when you feel down and  like there's not that much new to discover think  

of gyruses and all the other elephant-sized ducks  all around us invisible until we look more closely  

but how do you learn to look  at the world like a scientist  

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