Daniel Acosta-Avalos was born in Mexico and earned his PhD in Physics in 1997. He works in the Brazillian Center for Research in Physics (CBPF), in Rio de Janeiro, Brazil, since 2006. His major research lines are magnetotaxis in magnetotactic bacteria and magnetoreception in social insects. Recently he starts to study the effect of very low frequency oscillating magnetic fields on animal behavior in collaboration with Dr. Natalie Belova from Russian Academy of Sciences.
Magnetotactic bacteria are able to align their swimming direction to the geomagnetic field lines because they possess a magnetic moment. These bacteria biomineralize magnetic nanoparticles, magnetite or greigite, inside a membrane. The membrane + nanoparticle set is known as magnetosome and intracellular magnetosomes are disposed in a linear chain. Cytoskeleton-like filaments are resposible for the mechanical stability of this chain. The genes responsible for the magnetosome membrane and for the cytoskeleton proteins have been largely studied: the mam genes. The magnetosome chain also confers to the bacterial body a magnetic moment that can be measured through different physical techniques. Because of their response to magnetic field inversions, magnetotactic bacteria are good models to study bacterial motion. Theoretical and experimental studies show that magnetotactic bacteria swim following a trajectory similar to cylindrical helix. Magnetotactic microorganisms have been observed avoiding regions with UV or violet-blue light of high intensity. If the intensity is lower, magnetotactic microorganims show photokinesis, increasing their velocity in the presence of red light and decreasing their velocity in the presence of green light, both relative to the velocity with blue light.
Part of the book: Microorganisms