Download Magnetotactic Bacteria

Magnetotactic Bacteria
Day 3
What is Magnetotactic Bacteria?
 “Magneto-”: Magnetic
 “-Taxis”: Behavioral
response to a stimuli
 First discovered by Richard
Blakemore in 1975
 Found worldwide in
marine habitats
http://senr.osu.edu/Organisms_Living_on_Earth.html
A Quick Review: What is Magnetism?
 Some electrons spin one
way and some spin
another way.
 Usually these electrons
cancel each other out.
 Extra unpaired electrons
can go either way and
become…
MAGNETIZED!
http://www.rug.nl/zernike/research/groups/phynd/research/spinp
olarizedtransport
A Quick Review: What are Magnetic
Fields?
 Magnetic Fields – Guides
which tell us which
direction compasses will
point
 Field lines start from the
north to the south
http://www.askamathematician.com/?p=4129
What is the Earth’s Geomagnetic Field?
 The Earth is like a giant
magnet with a geographic
AND magnetic north pole
and a south pole.
 Geographic North Pole =
Magnetic South Pole
 Geographic South Pole =
Magnetic North Pole
http://adventure.howstuffworks.com/outdooractivities/hiking/compass1.htm
What is the Earth’s Geomagnetic Field?
http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magearth.html
What is the Earth’s Geomagnetic Field?
 The Earth creates its
magnetic field from
electric currents in its
liquid iron-nickel core
 Magnetic Fields are
created when electrical
charges move.
 Magnetic Fields are not
always the same. They
change over time.
http://news.nationalgeographic.com/news/bigphotos/76158139.html
MOVIE:
http://geomag.org/info/Declination/magnetic_lines.avi
Why are Magnetotactic Bacteria
Magnetic?
 Contains Magnetosomes –
Organelles that contain
magnetite (Fe3O4) or
greigite (Fe3S4)
 Imagine magnetic crystals
 Generally 15-20
magnetosomes per
bacteria
http://www.ornl.gov/info/news/pulse/magbac_htm.jpg
Why are Magnetotactic Bacteria so
Interesting?
 The magnetosomes act
like a compass needle in
the bacteria.
 The bacteria are slightly
anaerobic (doesn’t like
oxygen very much)
 The magnetosomes (and
Earth’s magnetic field)
helps these bacterial reach
optimal (the best) oxygen
conditions.
Why are Magnetotactic Bacteria so
Interesting?
 Magnetotactic Bacteria
orient themselves
differently depending on
which hemisphere they
live in.
http://en.wikipedia.org/wiki/File:Hemisferio_Norte.png
 Northern Hemisphere –
The Earth’s magnetic field
lines point slightly down
(into the center of the
Earth)
http://visual.merriamwebster.com/earth/geography/cartography/hemispheres
.php
Magnetotactic Bacteria in Action!
MOVIE:
/www.youtube.com/watch?v=WR7j67TABzE
Applications for Magnetotactic Bacteria
 Magnetic separation of
materials
 MRI
 Hyperthermia
 Eradication of heavy
metals (Pollutant
absorbers and/or
biosensors)
 Cancer
 Microchips
 Carrier of antibiotics,
drugs, etc.
 Robotic technology
http://sciencespot.net/Pages/kdzgen.html