Combining Old and New Tricks: The Study of Genes, Neurons, and Behavior in Crayfish

Abstract

For over a century the nervous system of decapod crustaceans has been a workhorse for the neurobiology community. Many fundamental discoveries including the identification of electrical and inhibitory synapses, lateral and pre-synaptic inhibition, and the Na+/K+-pump were made using lobsters, crabs, or crayfish. Key among many advantages of crustaceans for neurobiological research is the unique access to large, accessible, and identifiable neurons, and the many distinct and complex behaviors that can be observed in lab settings. Despite these advantages, recent decades have seen work on crustaceans hindered by the lack of molecular and genetic tools required for unveiling the cellular processes contributing to neurophysiology and behavior. In this perspective paper, we argue that the recently sequenced marbled crayfish, Procambarus virginalis, is suited to become a genetic model system for crustacean neuroscience. P. virginalis are parthenogenetic and produce genetically identical offspring, suggesting that germline transformation creates transgenic animal strains that are easy to maintain across generations. Like other decapod crustaceans, marbled crayfish possess large neurons in well-studied circuits such as the giant tail flip neurons and central pattern generating neurons in the stomatogastric ganglion. We provide initial data demonstrating that marbled crayfish neurons are accessible through standard physiological and molecular techniques, including single-cell electrophysiology, gene expression measurements, and RNA-interference. We discuss progress in CRISPR-mediated manipulations of the germline to knock-out target genes using the ‘Receptor-mediated ovary transduction of cargo’ (ReMOT) method. Finally, we consider the impact these approaches will have for neurophysiology research in decapod crustaceans and more broadly across invertebrates.

Elegant Nematodes Improve Our Understanding of Human Neuronal Diseases, the Role of Pollutants and Strategies of Resilience

“…Taken together, the list of C. elegans models for neuronal diseases is growing and getting more elaborate. The current invertebrate disease models are ready to elucidate the interactions between degeneration of distinct neurons, neuromuscular behaviors, age and environmental factors on a larger scale. , As outlined in the following sections, the study of genes, neurons and behavior along the entire life span of C. elegans may eventually close the evolutionary gap between nematode models and human disease by increasing our knowledge about the basic neurobiology of pollutant-induced neurodegeneration …”

“… 24 , 25 As outlined in the following sections, the study of genes, neurons and behavior along the entire life span of C. elegans may eventually close the evolutionary gap between nematode models and human disease by increasing our knowledge about the basic neurobiology of pollutant-induced neurodegeneration. 26 …”

Linking neural circuits to the mechanics of animal behavior in Drosophila larval locomotion

“…The use of isolated CNS enables researchers to reliably monitor calcium signals with high resolution. Isolated CNS has been employed to investigate neural activity in the spontaneous fictive motion in many animals, including vertebrates ( Grillner and Jessell, 2009 ; Garcia-Campmany et al, 2010 ; Grillner and Kozlov, 2021 ; Gosgnach, 2023 ) such as zebrafish ( Kyriakatos et al, 2011 ), tadpoles ( Roberts et al, 2010 ), turtles ( Paul and Stein, 2018 ), rats ( Falgairolle and Cazalets, 2007 ), and mice ( Falgairolle and O’Donovan, 2019 ), but also invertebrates ( Marder and Calabrese, 1996 ; Harris-Warrick, 2010 ; Selverston, 2010 ; Büschges et al, 2011 ; Mantziaris et al, 2020 ) such as leeches ( Kristan et al, 2005 ), crayfish ( Stein et al, 2022 ), locusts ( Mantziaris et al, 2020 ), stick insects ( Bidaye et al, 2018 ), crabs and lobsters ( Marder and Bucher, 2007 ), and cockroaches ( Ayali et al, 2015 ). By analyzing the spatiotemporal activity patterns during fictive larval behavior, the dynamics of motor circuits can be examined in detail.…”

The giant escape neurons of crayfish: Past discoveries and present opportunities

“…Progress has been limited compared to other genetically tractable invertebrate models because fully sequenced and annotated genomic data for crayfish was not available until very recently ( Gutekunst et al, 2018 ; Shi et al, 2018 ; Xu et al, 2021 ). Now, there seems to be a new urgency to integrate these useful molecular tools with existing experimental methods ( Stein et al, 2022 ; see contribution in this special topics issue). This will certainly shift focus towards a new set of exciting experiments, including ones that feature the crayfish giant circuits, which provide years of existing, detailed knowledge about their physiological function, and which link directly to adaptive behavior.…”