Theresa Logan-Garbisch

All Publications

• Satiety, TAX-4, and OSM-9 Tune the Attraction of C. elegans Nematodes to Microbial Fermentation Products. G3 (Bethesda, Md.) Logan-Garbisch, T., Fryer, E., Seyahi, L. S., Rogel-Hernandez, L., Rhee, S. Y., Goodman, M. B. 2025

  Abstract

  Animals are sensitive to selective pressures associated with nutrient acquisition, underscoring the evolutionary significance of chemosensation in foraging and its intersection with satiety. For the model nematode Caenorhabditis elegans, isoamyl alcohol (3-methyl-1-butanol) and 2-methyl-1-butanol are produced by microbial fermentation and present in bacterial food sources collected from the natural environments. Both compounds, which are structural isomers of one another, elicit strong attraction in laboratory settings. Using laboratory chemotaxis assays, we show that starvation attenuates attraction to both compounds. Well-fed C. elegans is largely insensitive to the biosynthetic precursors of both alcohols, with the exception of 4-methyl-2-oxovaleric acid, which is a mild repellent. C. elegans chemosensation relies on expression of tax-4 cyclic nucleotide-gated (CNG) and osm-9 transient receptor potential, vanilloid (TRPV) ion channels. Animals lacking both tax-4 and osm-9 are taste- and smell-blind. Animals lacking tax-4 fail to attract isoamyl alcohol and 2-methyl-1-butanol and those lacking osm-9 exhibit stronger attraction than the wild-type. Starvation not only attenuates attraction, but also enhances repulsion to 4-methyl-2-oxovaleric acid and uncovers repulsion in tax-4 mutants absent in their well-fed counterparts. Collectively, these findings implicate satiety in regulating response strength, tax-4-dependent chemotaxis in attraction to isoamyl alcohol and 2-methyl-1-butanol, and osm-9-dependent chemotaxis in suppressing responses to biosynthetic precursors.

  View details for DOI 10.1093/g3journal/jkaf245

  View details for PubMedID 41082586

• Valeric acid attracts C. elegans by activating the AWC neurons through a tax-4 -dependent signaling pathway. microPublication biology Sarkar, S., Rogel-Hernandez, L. E., Logan-Garbisch, T., Fryer, E., Johnson, V., Goodman, M. B. 2025; 2025

  Abstract

  Medicinal plants of the Valeriana genus have been traditionally used around the world to treat several nervous system disorders, yet our understanding of how they do so remains poorly understood. To deepen the understanding of their ability to influence nervous system pathways, we explored the ability of the model organism Caenorhabditis elegans to chemotax to crude extracts of Valeriana officinalis and found that C. elegans are weakly attracted to it. Upon investigating which chemical entities give rise to this behavior, we identified valeric acid (VA) as a primary candidate. Through chemotaxis assays, we show that wild-type C. elegans are strongly attracted to VA in a dose-dependent manner. Chemotaxis assays with mutant strains of C. elegans deficient in chemosensation indicate that the tax-4 -dependent nervous pathways are most heavily responsible for detecting VA. However, osm-9 -dependent pathways may also play a small role in regulating the worm's response to VA. Additionally, animals lacking AWC neurons are indifferent to this compound, and therefore, future research should focus on what molecular entities grant the AWC neurons the ability to detect VA.

  View details for DOI 10.17912/micropub.biology.001630

  View details for PubMedID 40485984

  View details for PubMedCentralID PMC12145527

• Satiety, TAX-4, and OSM-9 Tune the Attraction of C. elegans Nematodes to Microbial Fermentation Products. bioRxiv : the preprint server for biology Logan-Garbisch, T., Fryer, E., Seyahi, L. S., Rogel-Hernandez, L., Rhee, S. Y., Goodman, M. B. 2025

  Abstract

  Animals are sensitive to selective pressures associated with nutrient acquisition, underscoring the evolutionary significance of chemosensation in foraging and its intersection with satiety. For the model nematode Caenorhabditis elegans, isoamyl alcohol (3-methyl-1-butanol) and 2-methyl-1-butanol are produced by microbial fermentation and present in bacterial food sources collected from the natural environments. Both compounds, which are structural isomers of one another, elicit strong attraction in laboratory settings. Using laboratory chemotaxis assays, we show that starvation attenuates attraction to both compounds. Well-fed C. elegans is largely insensitive to the biosynthetic precursors of both alcohols, with the exception of 4-methyl-2-oxovaleric acid, which is a mild repellent. C. elegans chemosensation relies on expression of tax-4 cyclic nucleotide-gated (CNG) and osm-9 transient receptor potential, vanilloid (TRPV) ion channels and animals lacking both genes are taste- and smell-blind. Animals lacking tax-4 fail to attract isoamyl alcohol and 2-methyl-1-butanol and those lacking osm-9 exhibit stronger attraction than the wild-type. Starvation not only attenuates attraction, but also enhances repulsion to 4-methyl-2-oxovaleric acid and uncovers repulsion in tax-4 mutants absent in their well-fed counterparts. Collectively, these findings implicate satiety in regulating response strength, tax-4-dependent chemotaxis in attraction to isoamyl alcohol and 2-methyl-1-butanol, and osm-9-dependent chemotaxis in suppressing responses to biosynthetic precursors.

  View details for DOI 10.1101/2025.02.21.639594

  View details for PubMedID 40060391

  View details for PubMedCentralID PMC11888315

• A high-throughput behavioral screening platform for measuring chemotaxis by C. elegans. PLoS biology Fryer, E., Guha, S., Rogel-Hernandez, L. E., Logan-Garbisch, T., Farah, H., Rezaei, E., Mollhoff, I. N., Nekimken, A. L., Xu, A., Seyahi, L. S., Fechner, S., Druckmann, S., Clandinin, T. R., Rhee, S. Y., Goodman, M. B. 2024; 22 (6): e3002672

  Abstract

  Throughout history, humans have relied on plants as a source of medication, flavoring, and food. Plants synthesize large chemical libraries and release many of these compounds into the rhizosphere and atmosphere where they affect animal and microbe behavior. To survive, nematodes must have evolved the sensory capacity to distinguish plant-made small molecules (SMs) that are harmful and must be avoided from those that are beneficial and should be sought. This ability to classify chemical cues as a function of their value is fundamental to olfaction and represents a capacity shared by many animals, including humans. Here, we present an efficient platform based on multiwell plates, liquid handling instrumentation, inexpensive optical scanners, and bespoke software that can efficiently determine the valence (attraction or repulsion) of single SMs in the model nematode, Caenorhabditis elegans. Using this integrated hardware-wetware-software platform, we screened 90 plant SMs and identified 37 that attracted or repelled wild-type animals but had no effect on mutants defective in chemosensory transduction. Genetic dissection indicates that for at least 10 of these SMs, response valence emerges from the integration of opposing signals, arguing that olfactory valence is often determined by integrating chemosensory signals over multiple lines of information. This study establishes that C. elegans is an effective discovery engine for determining chemotaxis valence and for identifying natural products detected by the chemosensory nervous system.

  View details for DOI 10.1371/journal.pbio.3002672

  View details for PubMedID 38935621

• An efficient behavioral screening platform classifies natural products and other chemical cues according to their chemosensory valence in C. elegans. bioRxiv : the preprint server for biology Fryer, E., Guha, S., Rogel-Hernandez, L. E., Logan-Garbisch, T., Farah, H., Rezaei, E., Mollhoff, I. N., Nekimken, A. L., Xu, A., Fechner, S., Druckmann, S., Clandinin, T. R., Rhee, S. Y., Goodman, M. B. 2023

  Abstract

  Throughout history, humans have relied on plants as a source of medication, flavoring, and food. Plants synthesize large chemical libraries and release many of these compounds into the rhizosphere and atmosphere where they affect animal and microbe behavior. To survive, nematodes must have evolved the sensory capacity to distinguish plant-made small molecules (SMs) that are harmful and must be avoided from those that are beneficial and should be sought. This ability to classify chemical cues as a function of their value is fundamental to olfaction, and represents a capacity shared by many animals, including humans. Here, we present an efficient platform based on multi-well plates, liquid handling instrumentation, low-cost optical scanners, and bespoke software that can efficiently determine the chemotaxis valence of single SMs in the model nematode, Caenorhabditis elegans. Using this integrated hardware-wetware-software platform, we screened 90 plant SMs and identified 37 that attracted or repelled wild-type animals, but had no effect on mutants defective in chemosensory transduction. Genetic dissection indicates that for at least 10 of these SMs, response valence emerges from the integration of opposing signals, arguing that olfactory valence is often determined by integrating chemosensory signals over multiple lines of information. This study establishes that C. elegans is an effective discovery engine for determining chemotaxis valence and for identifying natural products detected by the chemosensory nervous system.

  View details for DOI 10.1101/2023.06.02.542933

  View details for PubMedID 37333363

  View details for PubMedCentralID PMC10274637

• Developmental Ethanol Exposure Leads to Dysregulation of Lipid Metabolism and Oxidative Stress in Drosophila G3-GENES GENOMES GENETICS Logan-Garbisch, T., Bortolazzo, A., Luu, P., Ford, A., Do, D., Khodabakhshi, P., French, R. L. 2015; 5 (1): 49-59

  View details for DOI 10.1534/g3.114.015040

  View details for Web of Science ID 000347826600006