A lovely article by Witze in last week’s Nature inspires thinking about how to get bacteria to behave as unhealthily as lines of humans drawn as if by magnets to burger joints.
|Magnetic particles in bacterium. |
From Chen, et al, 2012
But, doesn’t it make you wonder why some bacteria have special machinery to synthesize magnetic particles? One clue is that they tend to be anaerobic bacteria that live near a boundary with oxygenated water. Their magnetic crystals align them with the earth’s magnetic field, so they can swim only along the earth’s magnetic lines. How could that help, given that the earth’s magnetic fields go north and south? In the northern hemisphere, the magnetic lines dip downwards into the earth, so by turning their flagella counter clockwise and swimming straight towards the pole, they can reliably dive to deeper depths where there is less oxygen. In the southern hemisphere, the magnetic lines go up instead of down...so to get to the depths and away from oxygen, bacteria that evolved there swim away from the pole.