Biology subjects

Lockery, S. R.

Publications and source records attributed to Lockery, S. R..

3 recordsLinked to original sources

bioRxiv2022

Microinjection in C. elegans by direct penetration of elastomeric membranes

The nematode worm C. elegans is widely used in basic and translational research. The creation of transgenic strains by injecting DNA constructs into the worms gonad is an essential step in many C. elegans research projects. This paper describes the fabrication and use of a minimalist microfluidic chip for performing microinjections. The worm is immobilized in a tight-fitting microchannel one sidewall of which is a thin elastomeric membrane which the injection pipette penetrates to reach the worm. The pipette is neither broken nor clogged by passing through the membrane, and the membrane reseals when the pipette is withdrawn. Rates of survival and transgenesis are similar to those in the conventional method. Novice users found injections using the device easier to learn than the conventional method. The principle of direct penetration of elastomeric membranes is readily adaptable to microinjections in a wide range of organisms including cells, embryos, and other small animal models. It could therefore lead to a new generation of microinjection systems for basic, translational, and industrial applications.

bioengineering↗

bioRxiv2021

Worms get the munchies: the endocannabinoid AEA induces hedonic amplification in C. elegans by modulating the activity of the AWC chemosensory neuron.

The ability of cannabis to increase consumption of food has been known for centuries. In addition to producing hyperphagia, cannabinoids can amplify existing preferences for calorically dense, palatable food sources, a phenomenon called hedonic feeding. These effects result from the action of plant-derived cannabinoids on brain receptors where they mimic natural ligands called endocannabinoids. The high degree of conservation of cannabinoid signaling at the molecular level across the animal kingdom suggests hedonic feeding may also be widely conserved. Here we show that exposure of C. elegans to anandamide, an endocannabinoid common to nematodes and mammals, shifts both appetitive and consummatory responses toward nutritionally superior food, an effect analogous to hedonic feeding. We find that anandamides effect on feeding requires the C. elegans cannabinoid receptor NPR-19 but it can also be mediated by the human CB1 cannabinoid receptor, indicating functional conservation between the nematode and mammalian endocannabinoid systems for regulation of food preferences. Furthermore, the effect of anandamide in C. elegans is bidirectional, as it increases appetitive and consummatory responses to superior food but decreases these responses to inferior food. This bidirectionality is mirrored at the cellular level. Anandamides behavioral effects require the AWC chemosensory neurons, and anandamide renders these neurons more sensitive to superior food and less sensitive to inferior food. Our findings reveal a surprising degree of functional conservation in the effects of endocannabinoids on hedonic feeding across species and establish a new system in which to investigate the cellular and molecular basis of endocannabinoid system function in the regulation of food choice.

neuroscience↗

bioRxiv2019

An open source microfluidic sorter for Caenorhabditis nematodes

Rapid and accurate sorting of biological samples is extremely useful in a wide variety of applications. The model nematode Caenorhabditis elegans lends itself to automated fluid-flow based sorting because of its ability to live in aqueous solutions. Here, we build upon previous developments to construct a microfluidic device capable of sorting individuals based on a variety of characteristics, with a specific application toward differentiating fluorescently marked individuals. We find that our new design generates highly repeatable pools of sorted individuals. In general, there tends to be a tradeoff between precision and speed that can be optimized based on several different factors. Importantly, sorting does not decrease offspring production, and individuals can be sorted multiple times for increased precision. We provide detailed parts lists, schematics and software to allow implementation of these methods in other laboratories. Our results demonstrate that custom-made sorter chips can be a flexible and versatile addition to the nematode experimental toolbox.

bioengineering↗