Parasitic nematodes are a major health concern worldwide, and current strategies for preventing or eliminatingnematode infections are insufficient. One possible control strategy is to interfere with the ability of nematodesto locate their hosts. The long-term goal of my research is to better understand how parasitic nematodeslocate their hosts, using the free-living nematode C. elegans and the insect-parasitic nematodesHeterorhabditis bacteriophora and Steinernema carpocapsae as models for human-parasitic nematodes.Carbon dioxide is an important host-seeking cue for many parasitic nematodes, yet little is known about themechanism of CO2 response in nematodes. The overall goal of this proposal is to further our understanding ofhow parasitic nematodes respond to CO2. I have shown that C. elegans displays acute CO2 avoidance, and Ihave identified neurons and signaling pathways that are required for this response. I have also found thatanalogous neurons mediate CO2 attraction in H. bacteriophora. I will now further elucidate the signalingpathways and neural networks that mediate CO2 response in nematodes using molecular, genetic, andneurobiological approaches. I will test the hypothesis that the neural circuits that mediate CO2 response inparasitic nematodes are similar to the neural circuits that mediate CO2 response in free-living nematodes, butcontain modifications that reflect the host-seeking requirements of parasites.
Parasitic nematodes cause extensive morbidity and mortality worldwide. A better understanding of how parasitic nematodes find and infect their hosts will enable the development of new strategies for preventing nematode infections.
|Carrillo, Mayra A; Guillermin, Manon L; Rengarajan, Sophie et al. (2013) O2-sensing neurons control CO2 response in C. elegans. J Neurosci 33:9675-83|
|Chaisson, Keely E; Hallem, Elissa A (2012) Chemosensory behaviors of parasites. Trends Parasitol 28:427-36|
|Guillermin, Manon L; Castelletto, Michelle L; Hallem, Elissa A (2011) Differentiation of carbon dioxide-sensing neurons in Caenorhabditis elegans requires the ETS-5 transcription factor. Genetics 189:1327-39|
|Hallem, Elissa A; Spencer, W Clay; McWhirter, Rebecca D et al. (2011) Receptor-type guanylate cyclase is required for carbon dioxide sensation by Caenorhabditis elegans. Proc Natl Acad Sci U S A 108:254-9|
|Hallem, Elissa A; Dillman, Adler R; Hong, Annie V et al. (2011) A sensory code for host seeking in parasitic nematodes. Curr Biol 21:377-83|