Fast Measurement of population chemotactic behavior un C.elegans using a light microbeam sensing arena

BICHARA DR; BIANCHI JI; SIMONETTA SH

Heidelberg

Congreso; EMBL: C.elegans Neurobiology; 2012

EMBL

Animal’s ability to discern environmental cues, such as favorable or unfavorable chemical compounds, has been widely characterized in C.elegans. Chemotaxis experiments are usually employed to investigate synaptic function, search for nematicidal substances or try to understand habituation and memory experiences in worms. Although practical approach is mainly based on manually counting worms capable of migrating towards the compounds in agar plates, current technology could provide new methods with easier readouts and high-throughput capabilities. Our group has previously developed a method to track worm’s movement in liquid medium based on infrared light microbeam scattering, called worm microtracker. In this work we show the scaling-up of this methodology to build a sensing arena composed of 1680 light-microbeams covering the entire microplate surface. Worm populations were cultured in agar medium, and exposed to drops with different concentration of benzaldehyde, isoamylalcohol, heptane, NaCl, or CuSO4. Continuous recording of animal movement in the sensing arena let us measure the kinetic and spatial response to chemicals, and to distinguish between attractant and repellent substances. Obtained results show a high correlation with manually scored Chemotaxis Index, indicating the potentiality of this approach to develop new automated experimental procedures, with minimal to no need for operator eye-inspection.