Meeting Abstract

48.5  Sunday, Jan. 5 11:00  Magnetic orientation in C. elegans is mediated by a pair of magnetosensitive neurons VIDAL-GADEA, AG*; WARD, KA; TRUONG, N; PARIKH, A; BERON, C; PIERCE-SHIMOMURA, JT; The Univ. of Texas at Austin, Austin; The Univ. of Texas at Austin, Austin; The Univ. of Texas at Austin, Austin; The Univ. of Texas at Austin, Austin; The Univ. of Texas at Austin, Austin; The Univ. of Texas at Austin, Austin agvg75@gmail.com

The Earth’s magnetic field is a constant source of directional information for organisms able to detect it. For over half a century the list of species capable of this feat has grown steadily, while the mechanisms responsible for it remain elusive. Magnetotactic bacteria are known to build nanometer-sized “compasses” from iron in their environment. Evidence of similar biological magnetite has been reported in many magnetotactic animals. It remains unclear if and how animals may use these “biological compasses”. In no small measure, this is a consequence of the absence of an identified magnetosensory neuron in any animal. We show that the nematode C. elegans readily orients to the magnetic field of the Earth. Like bacteria, worms may use the magnetic field during vertical migrations. Using standard mutant analysis, cell-specific rescue and cell ablations, we identified a pair of sensory neurons as necessary and sufficient to mediate magnetotaxis in C. elegans. Functional calcium imaging performed on these neurons revealed calcium transients induced by magnetic fields. Magnetic orientation in C. elegans appears to take place through a light-independent mechanism, and to rely on a cGMP-dependent transduction pathway. To our knowledge, this represents the first report of sensory neurons required for magnetic orientation in any species.