Multiview motion tracking based on a cartesian robot to monitor Caenorhabditis elegans in standard Petri dishes

Joan Carles Puchalt,Jose F Gonzalez-Rojo,Antonio-José Sánchez-Salmerón,Ana Pilar Gómez-Escribano,Rafael P Vázquez-Manrique

doi:10.1038/s41598-022-05823-6

Abstract

Data from manual healthspan assays of the nematode Caenorhabditis elegans (C. elegans) can be complex to quantify. The first attempts to quantify motor performance were done manually, using the so-called thrashing or body bends assay. Some laboratories have automated these approaches using methods that help substantially to quantify these characteristic movements in small well plates. Even so, it is sometimes difficult to find differences in motor behaviour between strains, and/or between treated vs untreated worms. For this reason, we present here a new automated method that increases the resolution flexibility, in order to capture more movement details in large standard Petri dishes, in such way that those movements are less restricted. This method is based on a Cartesian robot, which enables high-resolution images capture in standard Petri dishes. Several cameras mounted strategically on the robot and working with different fields of view, capture the required C. elegans visual information. We have performed a locomotion-based healthspan experiment with several mutant strains, and we have been able to detect statistically significant differences between two strains that show very similar movement patterns.

Highlights

Caenorhabditis elegans is a 1-mm-long worm that is widely used as a model animal in biology, and in preclinical assays to test drugs, which may be used later in higher organisms before progressing to regular clinical studies[1]
Before going into more detail, at this point, we give a general description of the method presented in the current manuscript: It is based on a Cartesian robot (Fig. 1), which moves a carriage on the XY axes
To test our system we used three strains of C. elegans that shows no motor phenotype, worms showing a very mild phenotype and unc-1 mutants, which are severely impaired for movement

Summary

Introduction

Caenorhabditis elegans is a 1-mm-long worm that is widely used as a model animal in biology, and in preclinical assays to test drugs, which may be used later in higher organisms before progressing to regular clinical studies[1]. The simplest experiment to quantify is lifespan[1,3], which studies the conditions that induce and increase the lifespan of a given organism. Some of the traditional methods to quantify movement is to check the number of (1) thrashing in a time period[6], or (2) the maximum distance that the worm moves, from a given point, among others. Quantification of movement enables us to study the conditioning factors altering health, whether these are drug treatments, different food intake or inter-strain. These assays can identify harmful conditions (i.e. unhealthy food, drugs, deleterious mutations, etc.), so they can be neutralized. They can be promoted, if they are beneficial. There are several drawbacks in manual experiments that make automated experimentation essential

Methods

Results

Conclusion