Bacteria use a compass to navigate

Presented by:

Marwa Mahmoud

W hat does Christopher Columbus have in common with tiny

microorganisms?

Light Temperature FoodAnd alarm substances or other chemical compounds

Scientists have known for a long time that bacteria can orient themselves using:

Richard P. Blakemore in 1975, discovered the existence of magnetotactic bacteria in a mud sample. These bacteria have organelles called magnetosomes that contain magnetic crystals.

Freshwater and marine habitats.

Anaerobes -too much oxygen can kill them.

Mud-water interface. One micrometer (a thousandth of a millimeter) in size. Spiral, rod or comma shaped

life forms; some even resemble tiny footballs.

LIFE FORMS SHAPEDLIKE TINY FOOTBALLS

What is the structure of these extremely unusual nano crystals?

Figure 1: Diagram of a magnetotactic bacterium

Figure 2 : The electron microscopial images show structures in the shape of droplets (a), projectiles (b) and cubes (c, d). The magnetic particles are arranged in either one (a, b) or several (c, d) chains.

The magnetosomes present in various types of bacteria often have different shapes:

Figure 3: Diagram showing how magnetotactic bacteria use magnetotaxis to swim to the OATZ in the Northern versus the Southern Hemisphere on Earth

Figure 4: The microorganisms that are initially distributed uniformly and randomly, swim in a controlled manner to the northerly edge of the sample when a magnetic field is applied.

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Biotechnological application for medical diagnostics

Applications

Magnetosome particles could be usedin the detection of tumours (magnetic resonance tomography).

Help us to understand the origin of life on Earth and elsewhere in the universe.

Challenges We still have not managed to grow bacteria in

the laboratory in the required quantities.

The production of magnetite is particularly sensitive to subtle changes in the cultivation process.

And the greater the quantity, the more complex the procedure.

"Now, my own suspicion is that the universe is not only queerer than we suppose, but queerer than we can suppose. I suspect that there are more things in heaven and earth than are dreamed of, or can be dreamed of, in any philosophy.” J.B.S. Haldane

References:

1. Faivre, D. & Schüler D. Magnetotactic bacteria and magnetosomes. Chemistry Reviews 108, 4875–4898 (2008).

2. Gorby, Y. A., Beveridge T. J., & Blakemore R. P. Characterization of the bacterial magnetosome membrane. Journal of Bacteriology 170, 834–841 (1988).

3. Thomas-Keprta K. L. et al. Magnetofossils from ancient mars: a robust biosignature in the martian meteorite ALH84001. Applied and Environmental Microbiology 68, 3663–3672 (2002).