Microbiologist Dan Buckley joins WIRED to answer the internet's burning questions about microbiology. What's the fastest known bacteria? Is the zombie fungi from "The Last Of Us" realistic? Why is cat poop is dangerous for pregnant people? How did metal-eating bacteria come about? How does horizontal gene transfer work? What microbes should we be most concerned about? Dan Buckley answers these questions and many more await on WIRED Microbiology Support.
Director: Lisandro Perez-Rey
Director of Photography: Kevin Dynia
Editor: Richard Trammell
Expert: Dan Buckley
Line Producer: Joseph Buscemi
Associate Producer: Paul Gulyas; Brandon White
Production Manager: Peter Brunette
Production Coordinator: Rhyan Lark
Casting Producer: Nicholas Sawyer
Camera Operator: Christopher Eusteche
Sound Mixer: Gabe Quiroga
Production Assistant: Cerina Shippey
Post Production Supervisor: Christian Olguin
Post Production Coordinator: Ian Bryant
Supervising Editor: Doug Larsen
Additional Editor: Jason Malizia
Assistant Editor: Billy Ward
Director: Lisandro Perez-Rey
Director of Photography: Kevin Dynia
Editor: Richard Trammell
Expert: Dan Buckley
Line Producer: Joseph Buscemi
Associate Producer: Paul Gulyas; Brandon White
Production Manager: Peter Brunette
Production Coordinator: Rhyan Lark
Casting Producer: Nicholas Sawyer
Camera Operator: Christopher Eusteche
Sound Mixer: Gabe Quiroga
Production Assistant: Cerina Shippey
Post Production Supervisor: Christian Olguin
Post Production Coordinator: Ian Bryant
Supervising Editor: Doug Larsen
Additional Editor: Jason Malizia
Assistant Editor: Billy Ward
Category
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TechTranscript
00:00I'm Dan Buckley. I study microbes. Let's answer your questions from the internet.
00:04This is Microbiology Support.
00:10So, atculturepulp asks, wait, are there actual brain-eating amoebas?
00:15Yes. Yes, there are. The good news is that only a few people every year
00:20in North America end up running into one of these organisms. And if they do,
00:25there's not a lot of hope for you. Many of these cases are lethal.
00:28For example, there can be infections in Texas or sometimes in Mexico.
00:32The way that this happens might be if you jump off a rock face into really warm water,
00:37and the water just goes right up your nose. If it has one of these amoeba,
00:40an amoeba called Naegleria fowleri, might be able to get access to your brain.
00:45It's not designed to eat your brain, but if it finds itself up there,
00:48it's going to start eating and growing and dividing and dividing and dividing
00:52until you have millions and millions and millions of brain-eating amoebas up there.
00:56atbeehive01 asks, does the smell of farts tell you a lot about the microbiome of the gut?
01:02I assume a lot of it is driven by what we eat. Farts are 100% microbial.
01:06The microbes in your gut are helping you to digest your food,
01:09and when they break that down, they break it down into nutrients.
01:12You can also get volatile fatty acids.
01:14So, volatile fatty acids are small molecules like propionate, acetate, and butyrate.
01:19So, when you smell poop, what you're really probably smelling is butyrate.
01:24Normally, if your gut is functioning properly,
01:26these volatile fatty acids are being absorbed by your cells because they're a source of energy.
01:31That's where you get a lot of the energy from these microbes in your gut.
01:34But if you've got an imbalance in that system because you ate something bad,
01:38then some of these volatile fatty acids are going to come out with those farts,
01:41and that's when things are going to start to stink.
01:43So, if you ever smell garbage that's been sitting out on the street for a few days,
01:47you'll start to get these volatile fatty acid smells.
01:50You can also get methane out of your gut.
01:52So, about a third of human beings have methanogens.
01:55Methanogens use hydrogen and CO2, and they turn it into methane.
01:59These people, as well as people who make a lot of hydrogen,
02:02or maybe the people who are able to light their farts on fire, if you've ever seen that,
02:06you'll also smell sulfur.
02:07If you eat a lot of protein, that protein is going to have some sulfur in it.
02:11And the bacteria in your gut, when they break down that,
02:14they can make a gas called hydrogen sulfide.
02:16And hydrogen sulfide smells like rotten eggs.
02:18So, yeah, the smells you're getting are controlled by what you eat,
02:21but very much it's the microbes that make 100% of those smells.
02:24At Gothrin Fox asks,
02:26Do microbes dance?
02:27If so, how many could dance on the head of a pin?
02:29The head of a pin is pretty pointy.
02:32Maybe two microns, give or take.
02:33But a bacterium is typically about the size of two microns.
02:37So, if we were to zoom way in,
02:38we would see that it would have just about enough room for maybe one microbe,
02:42maybe two microbes.
02:43At Ed Wilson asks,
02:45If the number of microbial cells in a body is of the same order as that of human cells,
02:49how much of my weight is microbes?
02:51Add up all the cells in your body,
02:54and then add up all of the microbial cells in your body,
02:56we find that they're actually about the same.
02:59Microbial cells, bacteria in particular,
03:01are about a thousand times smaller than human cells.
03:04So, if we add up all of the mass of the bacterial cells,
03:07you're going to find that that's two to six pounds.
03:10So, a couple of kilograms.
03:11And that'll change throughout the day, right?
03:13Because when you go to the bathroom, when you poop,
03:16that poop is basically solid microbes,
03:18except for maybe the stray corn kernel or a little bit of lettuce,
03:22you've just lost a couple of pounds of microbes.
03:24But don't worry, they're going to grow back.
03:26At Rover Suede,
03:27What is the fastest bacteria?
03:29Like, if I were to stage a little race under a microscope, who would win?
03:32The fastest bacteria is Delavibrio bacteriovorans.
03:35Literally, that translates into the wiggly leech that eats bacteria.
03:39Its real speed is about maybe 150 microns per second,
03:42which is blazingly fast for a microbe.
03:44If we were to shrink ourselves down to the size of this microbe,
03:47it would be about 600 miles an hour, right?
03:49That's like the speed of a rocket car.
03:51So, you find them in freshwater habitats, typically.
03:54It's a predator of bacteria.
03:56So, they need to be really fast
03:57because they're chasing down those bacteria
03:59to try and attach to them and kill them.
04:01You almost can't see them
04:02because you're looking under the microscope
04:03and they sort of go,
04:05because they're just that fast.
04:06If you want to look at them under the microscope,
04:08you have to add something really viscous
04:10that's going to try to slow them down.
04:11At JeSwissCECE asks,
04:15Predatory bacteria.
04:16That shit is real AF.
04:18You are right.
04:18There are tons of predatory bacteria.
04:20So, these are bacteria that eat other bacteria.
04:23They come in a lot of different varieties.
04:25There are myxococcus.
04:26Myxococcus hunt in a wolf pack behavior.
04:29They talk to each other using molecules
04:32so they can zero in on prey
04:34and then they surround the prey
04:35and secrete enzymes that cause them to dissolve.
04:37There can be epibiotic parasites and predators
04:41like Vampirovibrio that latch onto the outside of a cell
04:45and suck its cytoplasm.
04:46And one of the most terrifying is Delavibrio.
04:49So, Delavibrio lives in aquatic habitats,
04:51usually freshwater,
04:53where it tracks down its prey.
04:54It will actually attach to the prey
04:57and then it will penetrate the cell wall
04:59and push itself inside of that cell
05:02where it will grow.
05:03It will replicate several times
05:04to make maybe eight or 10
05:06or as many as 12 cells
05:08inside of the guts of the prey cell
05:11that it's attacking.
05:12And then when it's done,
05:13they explode out
05:14and they swarm out.
05:15At Mitch Brown 43,
05:17my biology test was like,
05:18how do most bacteria move?
05:20A, magic.
05:20I didn't even need to read the rest of the answers.
05:22Bacteria move through a process called chemotaxis.
05:26Bacteria don't have eyes or ears like you or I,
05:29so they don't know where they're going.
05:30And so they do what we call a biased random walk.
05:33They keep sampling over time.
05:35Is it good?
05:36Is it better?
05:36They definitely move towards food
05:38so they can sense if the food concentration is high.
05:41And if it's bad or if it's getting worse,
05:43they just like shake themselves up,
05:45swim off randomly in a new direction.
05:46And through this random series of runs and tumbles,
05:49they actually are really effective
05:51at finding the right way to go.
05:53And then how do they get there?
05:54Well, there's lots of different ways that microbes move.
05:56So many microbes have a flagella,
05:58usually stiff and helical shaped.
06:00It spins and propels them.
06:02It helps them wiggle.
06:03But then when they want to run,
06:05they turn those flagella in the right direction
06:07and they all sort of coil up with each other.
06:09And that allows the bacteria to shoot forward.
06:11Some bacteria also move by what we call gliding.
06:14They sort of drive themselves along the surface
06:16with these suction cups.
06:18They're just one little cell out in the world.
06:19And so they need to find conditions
06:21that are right for them.
06:22Temperature, light, nutrients, salinity.
06:24They sense all of these things
06:26and then try to use this biased random walk
06:28to get where they need to go.
06:30At Newstart 2024,
06:31the last of us, zombie infection is real.
06:34Fungi can devour insects from the inside out.
06:36And experts say it's not too far-fetched
06:38that a similar parasite could evolve to infect humans.
06:40The clickers that you saw
06:42where the fungus infects people
06:43coming out of the person's head,
06:45I wouldn't worry too much about that
06:46unless you're an insect.
06:47The ophiocordyceps fungus
06:50infects many different kinds of insects,
06:52gets into their brain,
06:53and then causes these insects to move in such a way
06:56that promotes the distribution of the fungus
06:58so that more ants will become zombies.
07:00But insects are cold-blooded.
07:02They're very different from us.
07:03And so I wouldn't think that this fungus
07:05is going to infect people.
07:06If I was worried about a zombie infection for people,
07:09I would really think about rabies.
07:11Rabies is transmitted by a bite.
07:13If you're not vaccinated or treated quickly,
07:15it basically gets to your brain.
07:17It can make you maybe want to bite people.
07:19So we kind of do have a zombie infection.
07:22We just have really good vaccines for it right now.
07:24At Sublime Carnage,
07:26what microbe scares you the most?
07:28Honestly, following the newspaper,
07:29it's avian influenza.
07:31There's been avian influenza around for decades.
07:34The reason it's a problem now
07:35is there is a pandemic among the birds.
07:37It's all over North America.
07:39There are farmers who are dealing with this right now.
07:41Their chickens are getting sick.
07:43Their turkeys are getting sick.
07:44But it's a big problem for us too
07:45because that avian influenza can make people sick.
07:4740 or more million people died in 1918
07:50from the first flu pandemic.
07:52But then flu became seasonal.
07:53Then we have this avian flu.
07:55If those two flus happen to infect one person,
07:59those two strains of flu can recombine
08:01part avian influenza and human influenza.
08:04It's a little bit of both
08:05and neither 100% of either.
08:06And that's completely new.
08:08Our bodies have not seen that before.
08:10And so your prior vaccination won't matter.
08:12This will be a new pandemic
08:14that will be very problematic.
08:16At Niku Kesari asks,
08:18I'm just shocked there's a bacteria that eats metal.
08:20What in tarnation?
08:21There are lots of bacteria that eat metal.
08:23There are organisms that can eat chrome.
08:26They can eat uranium.
08:27They can eat all sorts of metals.
08:29They actually, in a real sense, breathe the metal.
08:32It's a kind of respiration.
08:34So all living things get energy
08:36by moving electrons from one place to another.
08:38Many of them will have something called nanowires,
08:40really small wires.
08:42So they conduct electricity.
08:44And so the microbes can then move electrons
08:46through that wire,
08:47either put those electrons down onto the surface
08:50or pull electrons off of the surface.
08:52And when it comes to organisms
08:53like iron-reducing bacteria,
08:55they're actually taking those electrons
08:57through the wires and putting them down onto a metal
08:59and causing that metal to be reduced.
09:01When we take electrons off of metal,
09:03for example, iron,
09:05we are oxidizing it.
09:06And oxidizing metal is rust.
09:08And if you look at pipes in factories
09:10or in pipelines or in boats,
09:13the pitting and the rusting of that metal
09:15is often catalyzed by microbes
09:16who are basically living off of that metal itself.
09:20AtCernLXXL asks,
09:22how can bacteria become resistant to antibiotics?
09:25So anytime there's a new change in the environment,
09:27the microbes are going to try to evolve
09:29in response to that
09:30so that they can be more successful.
09:32When we discovered antibiotics,
09:34we discovered those antibiotics
09:35because they were made by fungi and bacteria
09:38that live in soil.
09:39Those bacteria and fungi make antibiotics
09:41to kill each other.
09:42They're fighting with each other all the time.
09:44But then those organisms are going to evolve resistance.
09:47And they've had hundreds of millions of years
09:49of these back and forth warring
09:51with antibiotics and then antibiotic resistance genes.
09:53So we've been using antibiotics
09:55since like the 1930s and 1940s.
09:57The first antibiotics came from fungi,
10:00a scientist by the name of Fleming,
10:02discovered penicillium that makes penicillin,
10:04which was one of our first antibiotics.
10:05And there was also a really important discovery
10:07of streptomycin by a scientist
10:10by the name of Selman Waxman,
10:11who was a soil microbiologist, much like myself.
10:13So we've discovered the antibiotics.
10:15Woo-hoo, right?
10:16We can make antibiotics too, just like bacteria do.
10:18Well, the bacteria already have countermeasures.
10:21If those genes and those organisms
10:23come in contact with our pathogens,
10:25those pathogens, you know, they go to the app store.
10:27They're like, hey,
10:28do you have any antibiotic resistant genes
10:30that might be useful to me?
10:31And if they're useful,
10:32horizontal gene transfer gives you a conduit
10:34to get those genes.
10:35Evolution does the rest, right?
10:36Now we have antibiotic resistant pathogens.
10:39Antibiotic resistance in general
10:41is a real serious problem.
10:43And the way to fight it is to try and figure out
10:45how these organisms are evolving
10:47and try and use our antibiotics
10:48in a way that slows down that pace of evolution
10:50so that the antibiotics are more effective
10:52for longer time.
10:53AtSibsTHFC asks,
10:55can bacteria survive high temperatures
10:57and microwave radiation?
10:59Do we really need to clean out our microwaves?
11:01The reason you want to clean your microwave
11:02is because all that food just gets nasty in there.
11:05It's not because there are organisms
11:06that are evolving to be resistant to that radiation.
11:09The microbes in your microwave
11:11are going to be mostly like
11:12the ones we see on our sponge, right?
11:13They're going to be staphylococcus.
11:15They're going to be bacillus,
11:16maybe some pseudomonas.
11:17So probably they're going to end up
11:19dying in your microwave.
11:20Microbes themselves can survive
11:22really high temperatures.
11:23I think the record microbe can survive
11:26temperatures at 250 degrees Fahrenheit.
11:28And we definitely have microbes
11:29that can survive high radiation.
11:31So there's an organism by the name
11:32of Deinococcus radiadorans,
11:34the terrible radiation resistant ball.
11:37This organism is able to withstand
11:395,000 grays of radiation.
11:41People would be dead after maybe
11:43five grays of radiation.
11:44So Deinococcus is one of the most
11:46radiation resistant organisms on the planet.
11:48In fact, NASA has done experiments.
11:50They've found that Deinococcus
11:51can live for years in space.
11:53Many of these organisms that live
11:54in these unusual environments,
11:55we refer to them as extremophiles.
11:57At IO Silver Lining asks,
11:59oh dear God, what are extremophiles?
12:01We use the term extremophile
12:03to refer to microbes that thrive
12:05under conditions that would be
12:06pretty much lethal for most other organisms.
12:09We have thermophiles,
12:11which like really high temperatures,
12:13like Pyrococcus furiosus,
12:14the furious flaming fireball.
12:17Pyrococcus furiosus can live at temperatures
12:19above the boiling point of water.
12:21In fact, it thrives in those conditions.
12:23At the bottom of the ocean,
12:23there's really high pressure.
12:25That really high pressure
12:26changes the boiling point of water.
12:29And so we can have organisms like Pyrococcus
12:31living at volcanic seeps
12:33at the bottom of the ocean.
12:34We also have acidophiles.
12:36There are organisms that live
12:38in acid mine drainage.
12:39So this is like the runoff
12:40from a mining operation
12:42where the pH is 0.5.
12:44That's pure sulfuric acid.
12:46You can almost watch a nail rust
12:48under these conditions,
12:49but this is home for these guys.
12:50If there's liquid water,
12:52probably you have a microbe there
12:54and probably they've been
12:55living happily there
12:56for millions of years.
12:57AtSellerChun asks us,
12:59I'm doing microbiology
13:00and I genuinely don't know
13:01the difference between
13:02bacteria, fungi, and viruses.
13:04What a joke.
13:04Microorganisms in general
13:06are just anything
13:07smaller than what you can see.
13:08We have some that are called cells.
13:10Cells have a membrane.
13:12They have a cytoplasm.
13:13We have one kind called a prokaryote,
13:15which is an organism
13:16that has no nucleus.
13:18It came first.
13:19They evolved 4 billion years ago
13:21and they split into two groups,
13:22bacteria and archaea.
13:24Eukaryotic cells evolved much later.
13:26Eukarya have a nucleus
13:28and many of the eukaryotic cells
13:29are single-celled organisms,
13:30but they evolved into
13:32dogs and cats and plants
13:34and all the macroorganisms
13:35that we see today.
13:36And there's fungi,
13:37eukaryotic organisms.
13:38Maybe they live in soil.
13:39Maybe they look a little bit
13:40like this guy.
13:40And then the bacteria would look
13:42a little bit more like this,
13:43a little bit more slimy,
13:44a lot less fuzzy.
13:45You have cells, viruses,
13:46and that's most of your microbial world.
13:49SpaceSciStef asks,
13:50I just learned like 10 seconds ago
13:52that there are magnetic bacteria.
13:53There are magnetic bacteria.
13:55Magnetic bacteria
13:56have little magnets
13:57that are inside of their cytoplasm
13:59that help the bacteria
14:00line themselves up
14:01with magnetic fields.
14:02They use that like a compass
14:04that helps them change directions.
14:05Why would a bacterium need a magnet?
14:07We live on a sphere, right?
14:09The magnetic pole
14:11is not directly north.
14:12It's actually directed
14:13a little bit down.
14:15So if I were to point
14:16straight towards the magnetic north,
14:18it would be in that direction.
14:19And so bacteria know this, right?
14:21So when they're swimming north,
14:22they're actually swimming down.
14:24And so these bacteria
14:25live in sediments,
14:27usually where you have
14:28water overlaying sand
14:30or something like that.
14:31There's oxygen up here
14:32and there's no oxygen down there.
14:34By swimming north to go down
14:36and south to go up,
14:37they can position themselves
14:39in the right position
14:40with respect to oxygen.
14:41And in fact, it was a group in Europe,
14:42they invented a micro manipulator
14:45that controlled some magnets
14:46and they attached it
14:47to an old Nintendo
14:48video game controller
14:49and get the microbes
14:50to sort of swim around
14:51and do whatever dance they wanted.
14:53They actually put it to music.
14:54You could look it up on YouTube.
14:56At Ashley Maria asks,
14:57ever wonder what kind of germs
14:59are on the subway poles you hold?
15:00Microbes need water to live.
15:02So wherever you have water,
15:03you're probably going to
15:04have a lot of microbes.
15:05The subway pole, it's dry.
15:07There's actually pretty
15:07few microbes on there.
15:09But if we did find microbes in there,
15:10it's probably from
15:12one or two sources, right?
15:13The one source is us.
15:15Our skin constantly sloughs off.
15:17And because our skin
15:18is covered with microbes,
15:19when we slough off that skin,
15:21the microbes come off too.
15:22And so anytime you're in
15:24an indoor environment,
15:25the dominant microbes
15:26are going to be those microbes
15:27associated with skin.
15:28One of our more common organisms
15:30is staphylococcus.
15:31This is a scanning electron
15:33microscopic image of some bacteria
15:35that someone grew from a surface
15:37not dissimilar from your subway pole.
15:39These little balls of grapes.
15:41These are staphylococcus aureus,
15:42which is one of the most
15:43common organisms on our skin.
15:45It's called aureus
15:46because it makes a gold color
15:47when it grows on a Petri plate.
15:49Most of the staph
15:49that you're going to encounter
15:50is not dangerous,
15:51but there are some staph
15:52that have antibiotic resistance genes
15:55that have toxin genes
15:56that can cause pretty bad infection.
15:58So if you get an infection in a hospital,
16:00it's probably from a
16:02multidrug resistant staph aureus
16:04or methicillin resistant staph aureus.
16:06Probably the organism
16:08on your pole in the subway
16:10is not methicillin
16:11resistant staph aureus.
16:12But once we move outside,
16:13one of the things
16:13that would grow most vigorously
16:15and we see most common
16:16is an organism called bacillus,
16:17such as bacillus subtilis
16:19or maybe bacillus megaterium,
16:20bacillus cereus,
16:21this sort of wrinkly organism
16:23you're looking at right here.
16:24They live in soil,
16:25but because they make spores,
16:26they can survive a long time.
16:27At Haley Marie P says,
16:30I love tardigrades.
16:32How do they survive LMAO?
16:34Well, tardigrades are kind of crazy.
16:36They are microorganisms.
16:38They are eukaryotic.
16:39So they're made of cells
16:40that have a nuclei.
16:41They're multicellular,
16:42which is different from
16:43a lot of the microorganisms
16:44we've been talking about here.
16:46This is a very unusual
16:47and unique shape.
16:48It's not something
16:48we see a lot of
16:49in the microbial world.
16:50They are able to survive
16:51really harsh conditions
16:53by allowing themselves
16:54to be completely desiccated.
16:56The key too,
16:56is that when you rehydrate them,
16:58so you had to drop a water
16:59to this guy,
17:00you know, boom,
17:00he's ready to go.
17:01At Ho Adventures asks,
17:03why does cat poop
17:04have to be bad for pregnant people?
17:05All I want is a cat,
17:07RN.
17:07Cat poop can carry
17:08the cysts of toxoplasma.
17:10Toxoplasma is a parasite.
17:12It's not usually harmful to people,
17:14but it can cross the placenta
17:16and infect embryos
17:17and infect fetuses.
17:18And it is a cause of miscarriage.
17:20And so if you're pregnant,
17:21you definitely want to
17:22avoid the cat poop.
17:23Toxoplasma is actually
17:24a really interesting organism.
17:26Here we're seeing a toxoplasma
17:27next to our red blood cells.
17:29It cycles between different animals.
17:31So it's often found infecting mice.
17:34This parasite toxoplasma
17:36affects the mouse's brain
17:38and makes it more likely
17:39that that mouse is going
17:40to get himself killed by a cat.
17:41That actually helps the parasite
17:43because when the cat eats him,
17:44it ends up in the poop
17:45of the cat.
17:46So this is a way for these cysts
17:48to get spread wider and wider.
17:50At Hoe Adventures,
17:51if you really wanted to have a cat,
17:52have an indoor cat.
17:53Indoor cats are less likely
17:55to be exposed to toxoplasma.
17:56Or if you had somebody else
17:58in your household,
17:59clean the litter.
17:59At General Katana wants to know,
18:01but do amoebas f**k?
18:03No, amoebas don't f**k.
18:05Amoebas are asexual.
18:06They divide by binary fission.
18:08They split into two cells.
18:10Amoeba are in a group of organisms
18:12called protists.
18:13So protists have evolved
18:14many different ways of doing sex.
18:17And protists can also engage
18:18in something that bacteria do,
18:20which is called horizontal gene transfer,
18:22which is where maybe you move
18:24individual pieces of DNA
18:25back and forth as well.
18:26At Max Larder asks,
18:28how the duck does horizontal gene transfer
18:30work in viruses?
18:31We use the term horizontal
18:33to contrast from vertical.
18:35In vertical transfer,
18:36this is like a family tree.
18:37You have your great-grandparents,
18:39then your grandparents,
18:40then your parents,
18:41then you.
18:41Horizontally is like taking DNA
18:43from you and sending it to
18:46somebody you've never met before.
18:47That's something that microbes do
18:49all the time,
18:49and it's super important
18:50for their evolution.
18:51So for viruses,
18:52this is kind of tricky
18:54because viruses are not cells.
18:55Viruses are basically
18:56just a chunk of nucleic acid
18:58with a little bit of protein around it.
19:00So how do they exchange information?
19:02Well, they do it when they're in a cell.
19:04And while they're inside of a cell,
19:05they're making copies,
19:06lots of little baby viruses.
19:07When they're doing this,
19:08they could pick up a piece of DNA
19:10from the bacterial genome.
19:11And then when they package
19:12a new baby virus
19:13and it goes out into the world,
19:14it's picked up that DNA.
19:16So the virus wins
19:17by giving these genes to the cells,
19:20which then make those cells
19:21more effective pathogens.
19:22And so this horizontal transfer
19:23is just super important
19:24for the evolution of microorganisms.
19:26We have a question from
19:27at saditha anuhas2.
19:29What's the largest bacteria
19:31found so far?
19:32The largest bacteria currently
19:33is Thiomargarita magnifica,
19:35two centimeters long
19:36and about 50 microns in diameter.
19:39So this is almost
19:40the size of a human hair.
19:41So it's something you could
19:42see with your eyes.
19:43It was only discovered
19:44about two years ago,
19:45living in the mangroves.
19:46People saw these sort of fuzzy things
19:48and thought,
19:48what could that possibly be?
19:50But looked at it on the microscope
19:51and found out,
19:51hey, this is actually a bacterium.
19:53At Solbrah asks,
19:54did you know the little creatures
19:56in your gut control your cravings?
19:57They themselves want the sugar,
19:59et cetera, processed foods.
20:01The cravings stop after a while
20:02because the microbiome
20:03that was eating the garbage dies out.
20:05This is actually plausible.
20:06Microbes in your gut
20:07are playing a really important role.
20:09They're helping you
20:10to break down your food.
20:11In fact, pretty much
20:12all the plant material you eat,
20:13you would be unable to digest those
20:15without the bacteria
20:16in your large intestine.
20:17They break it down into materials
20:19that are nutrients for us,
20:20but they also make other chemicals, too.
20:22Some of these chemicals
20:23can cross into your blood.
20:25Some of these molecules
20:27are very similar to hormones
20:29that can control how we feel.
20:30So how hungry we are
20:32or how full we feel
20:33or maybe our moods.
20:34There have been experiments in mice
20:37that have provided evidence
20:38to support that changes
20:40in your gut composition
20:41could affect your behaviors.
20:43Hard to do these experiments with people,
20:44but certainly this is plausible.
20:46At Ruth V. MD asks,
20:49how about fecal transplant
20:50for improved microbiome?
20:52We take antibiotics all the time
20:53to treat infections,
20:55but these antibiotics,
20:56you know, they kill microbes.
20:57So they're going to kill
20:58a lot of the microbes in your gut.
20:59And if you take antibiotics,
21:00often you'll find
21:01that you'll end up with diarrhea.
21:02Usually this just resolves itself.
21:04Your microbes will grow back.
21:06But sometimes there can be an organism
21:08called Clostridium difficile.
21:09And you can think of this
21:10as like a weed.
21:11It's an organism that
21:12if it's too abundant,
21:14it becomes a problem.
21:15Often C. diff, as we call it,
21:17is resistant to antibiotics.
21:19And so when you take those antibiotics,
21:20they kill off your healthy microbes
21:23and C. diff doesn't get killed off.
21:25And because it's like a weed,
21:26it can grow and take over.
21:27You could die from a C. diff infection.
21:29And so the best treatment right now
21:32for this kind of infection
21:34is a fecal transplant.
21:35You'd get a donor.
21:36Usually that's going to be
21:37a member of your family.
21:38And you'd make the nastiest milkshake
21:40ever. Put this stuff in a blender.
21:42You'd mix it up into a slurry.
21:43You'd put it into a tube.
21:44And then the tube goes
21:45where the sun don't shine.
21:46You can reintroduce,
21:48sorry for that,
21:48the healthy kind of organisms.
21:50And once you have
21:50your healthy microbiome back,
21:52it will suppress this disease and cure it.
21:54At LemmyOTW.
21:56So what do microbiologists do
21:57when there isn't a pandemic
21:58endangering lives?
22:00There's a lot to do.
22:01Microbes are the most diverse
22:02organisms on the planet.
22:04Only about maybe 10,000
22:05or 20,000 of them
22:06have been described.
22:07Most of them have yet to be discovered.
22:09They've yet to be named.
22:10And when we're not doing that,
22:11we're also trying to predict
22:13the next pandemic.
22:14So if you would have asked
22:15a microbiologist 20 years ago,
22:17what are the most dangerous,
22:19scary microbes out there?
22:20Coronavirus, even 20 years ago,
22:22would have made the top five.
22:23And that's because we know
22:24that a lot of viruses from bats
22:26can jump over and infect people.
22:28And so when this pandemic started,
22:30we were really poised to move quickly.
22:32The fact that we were able
22:33to get a vaccine in a year
22:35is an indication of how much work
22:36microbiologists were doing
22:38in the off season.
22:39At Lubos Kulak asks,
22:41NASA's Perseverance rover
22:43just found something wild on Mars.
22:45Not saying it's aliens,
22:46but this rock has features
22:47super similar to what microbes
22:49would leave behind if Mars
22:50was teeming with life
22:51billions of years ago.
22:52What do you think?
22:53I think it's likely that
22:54there might've been life on Mars.
22:56The rocks that NASA just found on Mars
22:58have a couple of really
23:00interesting characteristics.
23:01Number one, they're sedimentary rocks.
23:03So they're rocks that were
23:04formed underwater.
23:05And we know that water
23:06is really important for life.
23:07The other thing that's
23:08really important about these rocks
23:09is they have evidence
23:11of organic molecules.
23:12Molecules typically associated
23:14with living things.
23:14They can be food for cells,
23:16but also the cells when they die,
23:18their little dead bodies
23:19make organic molecules.
23:20But those rocks,
23:21if they can bring them back to Earth,
23:23we would be able to determine
23:25whether or not those organics
23:26are biosignatures
23:28or evidence of life.
23:29So the real limitation on Mars
23:30is that it's very dry right now.
23:32But in the past, it's been wet.
23:34So the question was,
23:35did microbes live in the past?
23:37If they still live,
23:38the question would be,
23:39are they living probably underground?
23:41At Nile FM asks,
23:43you'll find more germs
23:44and bacteria on a tablet
23:45or mobile phone screen
23:46than on a toilet seat.
23:48Is this true or false?
23:49That would actually be true.
23:50If we were to look at
23:51both of these surfaces,
23:52they're very dry
23:54and they're also often wiped down
23:55and they're very smooth.
23:56And so as a consequence,
23:58there's not going to be
23:58a whole lot of bacteria
23:59on either one of them.
24:00If you do want to look for bacteria,
24:02you can look right there.
24:03So keyboards have a lot of bacteria.
24:04And the reason for that is
24:06they collect dust, right?
24:07There's lots of space
24:08in between those keys.
24:09One of the places you're going to find
24:11the most gnarly stuff
24:12is your kitchen sponge
24:13or your wash rag.
24:14And that's because it's often wet.
24:16It's often getting a lot of food, right?
24:18There's a lot of surface area
24:19because it's porous.
24:20So the microbes can live,
24:22survive and grow in that.
24:23And so you definitely want to
24:24let that thing dry out
24:25and you want to wash it frequently.
24:27If you have a fish tank,
24:28that is full of microbes,
24:30particularly that filter in the back.
24:31That's like a rainforest
24:32living in that thing.
24:33At Waterwolf4 asks,
24:35did you know there are more beneficial microbes
24:38in 10 square meters of healthy soil
24:40than all other animal
24:41and plant species on the planet?
24:43Hashtag organic.
24:44Just to give you an idea
24:45about how complicated
24:46the soil microbial community is,
24:48we could look at say
24:50a 10 meter square section of soil,
24:5210 centimeters deep,
24:54because that's where
24:54the best soil is going to be.
24:56We'd have about 12 million grams
24:58of soil in that patch.
24:59We have about one times
25:0110 to the nine bacteria per gram of soil.
25:03That's a billion bacteria per gram.
25:05We multiply those,
25:06we have 1.2 times 10 to the 16 bacteria
25:09just in that outdoor backyard patch.
25:12If we line those guys up end to end,
25:1410 to the 16th bacteria,
25:16each one is about one micron long,
25:18we would find we have about
25:1910 billion, with a B,
25:21meters of bacteria,
25:22enough to get to the moon
25:24and beyond about 30 times of bacteria
25:27lined up end to end
25:28living in that 10 square meter patch of soil.
25:30So our next question is from
25:32at Marlene MZ.
25:33How do microbiologists leave their house
25:35after knowing what they know?
25:36One thing you learn
25:37when you're a microbiologist
25:39is everything you touch,
25:40everything you eat,
25:41everything you drink
25:42is full of microbes.
25:43If we had people coming to this planet,
25:46they could be mistaken for thinking
25:47that the dominant form of life is microbial
25:49because most cells on this planet are microbes.
25:52And the secret is
25:53most microbes don't hurt you.
25:55One of the really important jobs
25:56that microbes do
25:57is to make the oxygen
25:59in the air that we breathe.
26:0130% of our oxygen
26:02is coming from plants,
26:04but most of it comes from microbes.
26:05Billions of years ago,
26:06there's no oxygen,
26:08hydrogen sulfide,
26:09toxic gases,
26:10uninhabitable planet.
26:11But once the cyanobacteria show up,
26:13they turn it into a world
26:14that we can live on.
26:15We couldn't live on this earth
26:17without the microbes
26:18doing their job for us.
26:19At Daniel Sprocket,
26:21calling all hashtag microbe tweets.
26:23What do you think is the most important
26:24or interesting unanswered question
26:26in hashtag microbiology?
26:28The vast majority of microbes
26:30out there in the world,
26:30the super mass majority,
26:32we don't know anything about them.
26:33It's very difficult to identify
26:36these microbes under the microscope.
26:37Most of the microbes,
26:38when we put them on a Petri plate,
26:40they just don't grow.
26:41So within the last 10 or 15 years,
26:42we've developed genomic technologies
26:45like metagenomics.
26:46When we sequence all of the DNA
26:48from a particular sample.
26:50And so if we have something like soil,
26:52it has thousands,
26:53tens of thousands of different species.
26:55They all have genomes.
26:56So there's millions of genes.
26:58We can sequence all of their DNA
27:00like a great big jigsaw puzzle.
27:01And when we do that,
27:02we see that the vast majority of these species
27:04don't match anything that we've described.
27:07Microbiologists call this
27:08microbial dark matter.
27:09When we think about dark matter
27:11in terms of astronomy,
27:12we think about this material
27:14that sort of pulls the shape
27:16of the universe together,
27:17which you can't really see in a telescope.
27:19We don't know what it is,
27:20but it's out there.
27:21Well, it's the same with microbes.
27:22At Evan Pro asks,
27:23can microbiologists identify
27:25common bacteria by smell?
27:26Like can they smell a wet towel
27:28or a dumpster or wilted broccoli
27:30and say, ah, good old Clostridium preferentians?
27:32Or do bacteria mostly smell the same?
27:34We can identify a lot of smells
27:36that are associated with certain organisms
27:38or processes.
27:39For example, there are organisms
27:41called Pseudomonas.
27:42If you smell them,
27:43lift the plate up and do one of these.
27:45If you got the smell of grape jelly,
27:47that might give you a clue
27:48that that's a Pseudomonas.
27:49So many Pseudomonas smell like grapes.
27:51There's an organism I study
27:52called Streptomyces.
27:53Streptomyces live in soil.
27:55If you've ever gone outside
27:56after the rain
27:58and you smell that earthy goodness,
28:00right?
28:01That's actually the odor
28:03made by these Streptomyces.
28:04So they make a compound called jasmine.
28:06And that's what you're smelling
28:07when you smell the rain hit the soil.
28:09So those are all the questions for today.
28:11Thanks for watching Microbiology Support.