Name: Can a Virus Get a Virus?
Uploaded: 2024-06-20T12:15:50.000Z
Duration: 5 min 1 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

This video was sponsored by LastPass.  Hey there!

Welcome to Life Noggin!  Getting sick is the absolute worst, but it's just a part of being, well, alive.

Relative clauses (Restrictive vs. nonrestrictive)

On Earth, every living organism has at least one virus that can infect it, from plants and animals to bacteria and single-celled archaea.  But what about non-living things?

You've probably heard that viruses aren't technically alive, so can a virus catch another virus?  Before we get into the nitty-gritty, I wanted to thank LastPass who sponsored this video.

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And now, back to the episode.  So, can a virus catch another virus?

Viruses are simple, submicroscopic parasites, a hundred times smaller than bacteria.

Without a metabolism or proteins for transcription and replication, they're little more than zombies borrowing life from other creatures.  So if viruses can't even keep themselves alive, how can they sustain another?

Nature, it seems, is always surprising us.

In the early 2000s, scientists discovered an exceptional virus that altered our understanding of life itself.

At first, experts assumed it was bacteria.

But what they actually found was a giant virus, so large that it could be glimpsed with a simple microscope.  Inside, the virus had many more genes than normal, encoding for proteins, metabolic pathways, even replication machinery.

Experts named it the mimivirus, short for mimicking microbe.

And soon, they began to find others just like it.

Because while the mimivirus was a surprise, the discovery of its relative, the so-called mamavirus, was a bombshell.

Slightly larger than the mimi, the mamavirus turned out to be hiding an itsy-bitsy virus of its own.  With just 21 genes, this little fella named Sputnik is the first example of a virus infecting a virus infecting an amoeba.

Since then, dozens of other virophages have been found.

And while there's still a lot we don't know about this madness, the basics are familiar.

After infecting its first host, Sputnik releases its DNA into the amoeba.

Unable to reproduce on its own, it then attaches to an already-present mamavirus, injecting its genetic material into that second host, too.

Once inside, this foreign DNA hijacks the host's viral factory so it can begin to replicate, ultimately making it harder for the mamavirus to do the same.

It's David and Goliath on a minuscule scale.  Today, we know virophages can infect both mama and mimiviruses, as well as plenty of others.

As such, some consider them viral parasites, representing a whole new class of virus, while others think that they are too basic to be called even that.

Whatever they are, they're probably important, and we keep learning more and more about virophages and giant viruses.  In fact, just last year, a paper was published stating that some giant viruses, called pandoraviruses, are so large they can encode thousands of proteins, 90% of which are not seen anywhere else on Earth.

Plus, not only do giant viruses appear to create genes, they also appear to steal them.

Sputnik and other virophages have remarkably similar genes to their hosts, which has experts wondering if these giant viruses are defending themselves by stealing genetic material from their viral parasites.  All that is still up for debate, but the idea that viruses can create and transfer genes does fit well with another theory.

More than a billion years ago, a giant DNA-based virus is thought to have infected a budding eukaryotic cell, somehow creating the first cell nucleus.

Like I said, nature is full of surprises.

Sometimes they're scary surprises, but still.  So are there any questions about the body that you have for us?

 Let me know now in the comment section below and your question could become a future video!  As always, my name is Blocko, this has been Life Noggin, don't forget to keep on thinking!