Advanced Behavioral Analyses Show that the Presence of Food Causes Subtle Changes in C. elegans Movement

Abstract

As a widely used and studied model organism, Caenorhabditis elegans worms offer the ability to investigate implications of behavioral change. Although, investigation of C. elegans behavioral traits has been shown, analysis is often narrowed down to measurements based off a single point, and thus cannot pick up on subtle behavioral and morphological changes. In the present study videos were captured of four different C. elegans strains grown in liquid cultures and transferred to NGM-agar plates with an E. coli lawn or with no lawn. Using an advanced software, WormLab, the full skeleton and outline of worms were tracked to determine whether the presence of food affects behavioral traits. In all seven investigated parameters, statistically significant differences were found in worm behavior between those moving on NGM-agar plates with an E. coli lawn and NGM-agar plates with no lawn. Furthermore, multiple test groups showed differences in interaction between variables as the parameters that significantly correlated statistically with speed of locomotion varied. In the present study, we demonstrate the validity of a model to analyze C. elegans behavior beyond simple speed of locomotion. The need to account for a nested design while performing statistical analyses in similar studies is also demonstrated. With extended analyses, C. elegans behavioral change can be investigated with greater sensitivity, which could have wide utility in fields such as, but not limited to, toxicology, drug discovery, and RNAi screening.

Bergerac strains of Caenorhabditis elegans revisited: expansion of Tc1 elements imposes a significant genomic and fitness cost

“…The average speed and direction change of N2 worms was concordant with the values observed by Angstman et al (2016) , despite our use of a different worm tracking program. Our N2 average speed was 177.8 μm/s ( Table 4 ) with an SD of 48.9 μm/s (SE 15.5) compared with an average 146.9 μm/s with an SD of 55.3 μm/s measured by Angstman et al (2016) .…”

“…The average speed and direction change of N2 worms was concordant with the values observed by Angstman et al (2016) , despite our use of a different worm tracking program. Our N2 average speed was 177.8 μm/s ( Table 4 ) with an SD of 48.9 μm/s (SE 15.5) compared with an average 146.9 μm/s with an SD of 55.3 μm/s measured by Angstman et al (2016) . Similarly, our N2 average direction change ( Table 4 ) was 0.531 radians/s with an SD of 0.218 radians/s (SE 0.069) compared with Angstman et al ’s (2016) average direction change of 0.70 radians/s with an SD of 0.30 radians/s, after converting their measurements from degrees to radians.…”

“…The temperature in the recording room was recorded at least three times for each assay and remained at approximately 21 ± 1°C. These details are provided to increase the reproducibility of our motility assay in a manner consistent with the suggestions of Angstman et al (2016) .…”

Loss of physical contact in space alters the dopamine system in C. elegans

“…Movement activities of adult hermaphrodites cultured in each condition was measured by thrashing assay (moving frequency: Hz) and maximal bending angle (degree) described, respectively, with slight modification (Angstman et al, 2016;Ellwood et al, 2021).The frequency for 10 sec of an individual that swims vigourously by gently pushing from outside of the culture bag. The maximal bending angle is defined as the angle between the midpoint-head and midpoint-tail segments, with a straight animal set as 0 degrees (Angstman et al, 2016). For a particular animal, we measured the bending angle of each tracked frame.…”

Bergerac Strains of C. elegans Revisited: Expansion of Tc1 elements Impose a Significant Genomic and Fitness Cost

“…The temperature in the recording room was recorded at least three times for each assay and remained ~21 ± 1°C. These details are provided to increase the reproducibility of our motility assay in a manner consistent with the suggestions of Angstman et al (2016).…”