RSI Research Seminar

Join us every other Monday at noon for lunch and a 30-minute research talk, presented by Resnick Sustainability Institute Graduate Fellows and Caltech researchers funded by the Resnick Sustainability Institute. To see the full schedule of speakers, visit the RSI Research Seminar web page. Seminars currently take place in a hybrid format, both in-person (Jorgensen building first-floor conference room) and via Zoom. For more information and to get the Zoom login info, please reach out to ramonae@caltech.edu

Soil-dwelling nematode Steinernema hermaphroditum as a vector for engineered E. coli

Entomopathogenic nematodes in the Steinernema genus are commonly used both in agricultural applications and in basic science as model systems. The infective juvenile (IJ) stage of the nematode carries mutualistic bacteria of Xenorhabdus spp in the intestinal pocket ­and migrates in the soil to seek for an insect prey. In addition to its mutualistic symbionts, Steinernema nematode frequently associates with other environmental microbes, providing a potential vector for bacteria amenable to genetic engineering. In this talk, we will present our work characterizing the association of E. coli in S. hermaphroditum IJs. We found E. coli cells localize to nematode tissues that are distinctive from Xenorhabdus symbiotic bacteria, suggesting a novel mechanism of nematode-bacteria interaction. In particular, the ability of E. coli to colonize IJ inter-cuticular space is promising for applying these nematodes as protective vectors for delivering engineered bacteria, such as sense-and-response circuits. We will also discuss the type of applications that could be explored based on our results. Our goal in the future is to use this system to deliver engineered biocircuits into the soil environment in a persistent manner.