hello
i'm dr michael behe i'm not a medical
doctor but i play one in this video
today we're talking about bacteria those
tiny invisible bugs that can make us
sick
and sometimes help make us better
thanks jane
valuable research is being done on these
single-celled microbes
in fact scientists are trying to develop
clever ways to use bacteria in targeted
medicine
here's one way
suppose this person has a tumor the idea
is to take human-friendly bacteria that
are pre-loaded with cancer-killing
agents
and inject them into the patient
these bacteria are self-propelled active
swimmers
a guidance system directs the bacteria
to the exact location of the tumor
the bacteria attack and destroy
only the cancer
the surrounding healthy tissue remains
unharmed
the key to the whole plan is to equip
the bugs with these precision engineered
magnetic crystals the crystals need to
form a row
this enables the crystals to interact
effectively with an external magnetic
field
the controller then maneuvers the
bacteria to the destination
it's a great idea but there are two big
problems
first no one has been able to synthesize
tiny crystals like these
second even if they could no one knows
how to get such crystals inside a
microscopic bacterium
well let me tell you a little secret of
the cell
magnetic bacteria aren't some futuristic
science fiction concept
they're real
they're here
and
these amazing bacteria manufacture the
magnetic crystals on their own without
the help of any scientists or engineers
this is an actual photo
meet the magnetotactic bacterium one of
the absolute marvels of the microbial
world
we usually think of nanotechnology that
can control creatures
as star trek kind of stuff
but magnetotactic bacteria don't live
such a glamorous life
they live here
on earth in murky water
life in the swamp can be perilous for
these little bugs if they swim in water
that has too much oxygen it can be fatal
for them so they have to swim down to a
depth that has little oxygen bacteria
don't have eyes and navigating muddy
water can be difficult
now here's where the crystals come in
amazingly the magnetic particles align
with earth's magnetic field
this guidance system enables the
bacterium to navigate to a favorable
environment
homing pigeons
sea turtles
salmon
frogs
these are among the many animals that
also use earth's magnetic fields for
orientation when they travel
so precisely how do the bacteria living
in swamp water make these magnetic
particles
well
within these microscopic bio wonders is
a factory
and i mean a real factory
when you peer inside a bacterium it's
hard to make out the complex micro
machines and systems that make it
function so for the moment let's portray
the components inside this bacterium in
a way that all of us can relate to
this is the magnetotactic bacterium
crystal factory it has a digital command
center quality control reactors
transporters and more it begins with
acquiring the raw materials the
bacterium it pulls the iron ions from
the surrounding water
then the process begins
let's see how it works
first the iron goes through a regulator
iron comes in two chemical flavors
called fe2 and fe3 a specific ratio of
the two is required so this machine
electronically converts the iron to
proportions of two fe3 for every one fe2
now a major problem has to be addressed
excessive amounts of iron are toxic to a
cell
fortunately the factory has a hazardous
materials solution
this is a magnetosome its protective
membrane encloses the iron
when we peek inside we can see that the
amazing magnetosome is a nano reactor
the iron particles are grown and
fashioned into these astonishing
magnetite crystals
finally these forklift guys transport
the magnetosomes they're carefully
placed along a special filament that
provides a guideline to achieve optimal
magnetic alignment
so it's a very impressive factory
but it's all made possible by what is
the key component for every modern
factory
the command center the bacterium's dna
all instructions for the entire
operation originate here
and what is truly remarkable is that the
final dimensions are all within specific
tolerances
oversized undersized or misshapen
crystals would impair magnetism but
thanks to their precise shape and
alignment the bacteria successfully
navigate to healthy depths
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so there you have it
a factory that would rival any modern
day fabrication plant
but wonders like magnetotactic bacteria
are fairly recent discoveries
today
we're able to peer inside tiny microbes
before modern microscopes like this one
our knowledge was limited and scientists
thought bacteria were just
run-of-the-mill squirmy bugs
with new technology we can now more
fully appreciate the complexity and
incredible features of magnetotactic
bacteria and many other kinds too
like this one some bacteria have a
flagellum which is like an outboard
motor on a boat the flagellum has highly
advanced components a rotor stator drive
shaft a universal joint bushings even a
clutch and brake
the amazingly efficient motor of the
flagellum can spin at up to 100 000
revolutions per minute
and check this out some bacteria have
guns
ammunition shot from these barrels has
enough force to pierce the membranes of
other cells
and the guns can shoot up to 60
molecular bullets per second
who knew bacteria were so well equipped
i mean it's astonishing but it gets
better
these tiny creatures have a huge role in
the well-being of our planet
and they touch each of our lives in ways
that might surprise you
stay tuned
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good luck with that nancy
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elon
what about you do you know what you want
to be when you grow up
i want to be a car maker but not just
any kind of car it's going to be
electric we won't have to use gas and
all the air pollution will go away
okay
elon very interesting
and steven what about you have you
thought about what you want to do
i want to make phones phones i can do
anything you can play music and watch
cartoons and even call batman
steven that sounds very ambitious
okay
uh michael what about you
i want to be a biologist and to what how
to grow super bacteria that eats poop
turns it into methane gas to run
electric power
plants okay
who's next
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you might not appreciate bacteria in the
same way you do a smartphone or an
electric car
but bacteria are amazingly complex and
can be surprisingly useful
and yes there actually are large dairy
farms powered by
manure
the valued cow chips are rounded up and
then sent to a large holding tank
inside manure eating bacteria converted
to methane gas
that fuels an on-site power plant which
produces more than enough electricity to
power the entire farm
the list of beneficial bacteria is quite
long
these bugs eat plastic waste materials
produced by humans that have littered
the oceans
some engineers are trying to harness
bacteria to potentially replace silicon
chips and computers
using the bugs to make smaller and
faster processors
and then there's the friendly bacteria
that benefit our health they're
essential to good digestion and healthy
skin
humans are composed of about 40 trillion
cells
about the same number of bacteria reside
on or inside each of us
perhaps much more although because
bacteria cells are so small
altogether they weigh only about 1 300th
of an ounce
finally there's this remarkable bacteria
discovered by a danish scientist
it actually cleans up um
odoriferous mud
the harbor had pungent smells
originating within the mud
the scientists found that the odor could
be deleted by a community of
collaborative bacteria
thousands of bacteria form a wire that
conducts electricity from the oxygen
deprived lower layer up to the
oxygen-rich surface
the electric current allows bacteria
deep in the mud to eat organic waste and
remove the smelly hydrogen sulfide
folks you can't make this stuff up
bacteria are incredible
it's true some types of bacteria are
harmful to humans
but countless others are superheroes of
the microbial world
all this raises an obvious question
how did bacteria become so diverse and
so ingenious
that's coming up next
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let's talk some more about factories
and what's cooler than a car factory
robots in perfect sink tons of steel
being shaped and welded together and
hundreds of cars coming off the assembly
line every day
and isn't it interesting to think about
how one wrong keystroke
can make the whole thing grind to a
complete stop
then
another to fully restore it
no we haven't changed the topic from
bacteria
but i do want you to think about what
makes a huge coordinated operation like
this possible
now back to the bugs
as we've seen they can do very clever
things
but the truth is
bacteria aren't smart they don't have
brains
they can't think or reason
bacteria can do many remarkable things
because they are
pre-programmed with goals and purposes
basically bacteria are
nanobots
in the same way that human computer code
enables sophisticated mechanical robots
to perform important jobs
bacteria have written code in their dna
that provides the instructions to do
things like manufacture magnetic
crystals
so we can see that even bacteria are
autonomous highly developed life forms
but how did they get that way
bacteria have been around since life
began on earth
through the ages
variations have cropped up in their dna
these are called mutations and they can
alter the structure of a cell
according to darwin's theory these small
changes are what drive evolution
what's more
darwin theorized that with myriad
mutations over vast stretches of time
enormous changes occurred
bacteria with helpful mutations survived
bacteria with unhelpful mutations were
eliminated by natural selection
mutations can cause small changes that's
easily observed in nature
but here's the critical question
can a sequence of many mutations added
together over time result in a major
gain of function
what might such an evolutionary process
look like for our old friend the
magnetotactic bacterium
how did it evolve by tiny steps
back in the days before they could
produce magnetite crystals ancient
bacteria might have been swimming along
foraging for food wherever they could
find it
then over a vast stretch of time a long
series of unguided mutations supposedly
occurred
our imagined result is that the bacteria
gained the ability to accumulate large
quantities of iron
then another long series of unguided
mutations resulted in the magnetosome
membranes to hold the toxic iron
after yet another long series voila
a magnetite crystal was produced
that's impressive but the problem is
that so far none of this would be
helpful to the bacteria
many eons later
more crystals show up
but they're of no value either unless
they're lined up
finally
the transporters arrange them on the
filament and the magnetic fields can be
accessed
but you can see
that it's not until all the pieces are
in place and fully functional
that there is an actual benefit to the
bacteria
color me skeptical
i'd like to suggest to you that the
parts of the magnetotactic bacterium did
not develop gradually over time through
random evolution
rather this amazing little creature has
all the characteristics of deliberate
intelligent design
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at the core of every modern factory is
sophisticated computer programming even
a tiny error can gum up the works
by the same logic as we look at the
astonishing factory that science has
discovered within bacteria
we realize it too requires very specific
instruction
from its dna code to build and run its
machinery
in darwin's time the bacterium was
thought to be a very simple organism
there didn't appear to be much to it
so back then it was easy for scientists
to imagine it could arise randomly
without much difficulty
but as science advanced we have
discovered that bacteria are
unfathomably complex
that functional complexity is
overwhelming evidence that these
nanobots were purposely
intelligently
designed
the topic of bacteria is immensely broad
to learn more about it check out the
articles videos and discussions on my
website
thanks for joining me and i'll see you
next time for more secrets of the self
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you