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J Neurogenet,
2021]
The pursuit of understanding behavior has led to investigations of how genes, the environment, and the nervous system all work together to produce and influence behavior, giving rise to a field of research known as behavioral neurogenetics. This review focuses on the research journeys of two pioneers of aspects of behavioral neurogenetic research: Dr. Marla Sokolowski and Dr. Catharine Rankin as examples of how different approaches have been used to understand relationships between genes and behavior. Marla Sokolowski's research is centered around the discovery and analysis of <i>foraging</i>, a gene responsible for the natural behavioral polymorphism of <i>Drosophila melanogaster</i> larvae foraging behavior. Catharine Rankin's work began with demonstrating the ability to learn in <i>Caenorhabditis elegans</i> and then setting out to investigate the mechanisms underlying the "simplest" form of learning, habituation. Using these simple invertebrate organisms both investigators were able to perform in-depth dissections of behavior at genetic and molecular levels. By exploring their research and highlighting their findings we present ways their work has furthered our understanding of behavior and contributed to the field of behavioral neurogenetics.
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MicroPubl Biol,
2023]
Scientists use Parafilm to seal Caenorhabditis elegans cultures on Nematode Growth Media (NGM) petri plates for short-term storage to reduce the likelihood of contamination and improve moisture retention. However, we found that maintaining worms on plates wrapped with Parafilm can affect multiple behavioral metrics when assaying tap-habituation behavior using the Multi-Worm Tracker (MWT). Most notably, worms cultured on parafilm-wrapped NGM plates exhibited slower speed of initial response to tap followed by marked sensitization. These findings suggest that labs should be conscious of the possibility that Parafilm may induce behavioral changes in C. elegans when conducting experiments.
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MicroPubl Biol,
2020]
The Auxin-Inducible Degradation (AID) system is a powerful technique in the C. elegans toolkit that enables conditional and reversible protein depletion with high temporal and spatial specificity (Zhang et al. 2015; Martinez et al. 2020; Ashley et al. 2020; Martinez and Matus 2020). This system relies on tagging a gene of interest with a short AID degron sequence and transgenic expression of TIR1, an inducible E3 ubiquitin ligase normally found only in plants (Nishimura et al. 2009; Zhang et al. 2015). Upon exposure to the plant-derived hormone Auxin, TIR1 is activated and targets AID-tagged proteins for proteasomal degradation (Nishimura et al. 2009; Zhang et al. 2015) (Figure 1A). While there are qualitative reports that Auxin does not overtly affect the morphology or behavior of wild-type C. elegans (Zhang et al. 2015), this has not been quantitatively assessed. Determining whether Auxin significantly affects C. elegans morphology and behavior, even in subtle ways, is important given the C. elegans communitys rapid uptake of the AID system (Kasimatis et al. 2018; Nance and Frkjr-Jensen 2019; Ashley et al. 2020; McDiarmid et al. 2020). Here, we use our high-throughput machine vision tracking system, the Multi-Worm Tracker (MWT) (Swierczek et al. 2011), to investigate whether exposure to Auxin affects a suite of morphological, locomotor, mechanosensory, and short-term habituation learning phenotypes in our labs derivate of Bristol N2 wild-type worms and the CGC wild-type reference strain, PD1074 (Yoshimura et al. 2019) (Figure 1B).
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J Neurosci,
1996]
The nematode tap withdrawal reflex demonstrates several forms of behavioral plasticity. Although the neural connectivity that supports this behavior is identified (Integration of mechanosensory stimuli in Caenorhabditis elegans, Wicks and Rankin, 1995, J Neurosci 15:2434-2444), the neurotransmitter phenotypes, and hence whether the synapses in the circuit are excitatory or inhibitory, remain uncharacterized. Here we use a novel strategy to predict the polarity configuration, i.e., the array of excitatory and inhibitory connections, of the nematode tap withdrawal circuit using an anatomically and physiologically justifiable dynamic network simulation of that circuit. The output of the modeled circuit was optimized to the behavior of animals, which possessed circuits altered by surgical ablation by exhaustively enumerating an array of synaptic signs that constituted the modeled circuit. All possible polarity configurations were then compared, and a statistical analysis was used to determine whether, for a given synaptic class, a particular polarity was associated with a good fit to behavioral data. The results from four related experiments were used to predict the polarities of seven of the nine cell classes of the tap withdrawal circuit. In addition, the model was used to assess possible roles for two novel mechanosensory integration neurons: DVA and PVD.