a rotation project in Astra Bryant’s lab
project overview
Strongyloides stercoralis are parasites that infect over 600 million peoole (fleitas et al., 2022) (studying parasitic nematodes improves public health crisis). They have a life cycle that occupies two very different environments - one inside of the host and one in the soil. These two environments vary widely in temperature, which is the primary mechanism for which these organisms find hosts. We do not yet know much about the fundamental biology of these parasites and how they are able to navigate these different thermal environments throughout their lives. One really interesting life stage that is unique to strongyloides, is their free living adult stage. This is a life stage where the eggs hatch and are voided on feces but then go through a single non parasitic life stage in the soil.
My rotation project was focused on comparing free-living strongyloides to parasitic adults. These two life stages are genetically identical yet they respond completely different do stimuli and to different environments. For one, we know that parasitic adults live substantially longer than free living adults. they can, live for months in the host compared to just a couple days of the free living adults in the soil. As you increase temperature, worms are less temperature resistant (including c elegans). Interestingly, survival is not cell autonomous, it depends on the thermosensory neuron AFD in c elegans (AFD neurons are required for positive thermotaxis), but is this also true in parasites? We know that parasites are more temperature resistant than c elegans but the free living adults still die after a couple of days at increased temperature. Despite dying quickly, they lay more eggs than at room temperature. This is very surprising, suggesting that thermosensory neurons may also be involved in brood size as well as survival!
In my rotation, I generated a construct to ablate AFD neurons in strongyloides. I designed a plasmid to express miniSOG (PH-miniSOG optogenetically ablates cells) and injected into strongyloides. With more time, I would start to answer the question of whether thermosensory neurons (AFD) are important for survival and fecundity by ablating those neurons and seeing how this changes these variables.
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literature
Schafer2016
Bryant.etal2018
Bryant.etal2022
Xu.Chisholm2016
Mendez.etal2022