Background
Animal venoms are complex cocktails of bioactive polypeptides, known as toxins, that potently and selectively target important physiological processes in their victims. These toxins are produced and delivered to their victims using in specialised glands (i.e., venom glands) and delivery structures that together form the venom apparatus. Recently, it has become clear that in some venomous animals, toxins are produced in discrete locations in the venom producing tissue(s). These findings have provided new insights into the functional ecology of toxins1 as well as fundamental physiological processes that affect the evolution of venom2. They also raise the question of whether such distinct toxin distributions are found in other venomous lineages.
One such venomous lineage is the Glyceridae (Polychaeta), which is a family of venomous marine worms sometimes referred to as blood worms. Although their venomous nature is well known, the composition of their venom remains enigmatic, with only a single major venom component having been characterised to date. Studies on the tissue-specific expression of this toxin also recently led to a redescription of the glycerid venom apparatus3, which included the identification of a previously overlooked set of glands that appear to play a key role in venom production. We have since obtained detailed proteomic data on the venom composition of several species of glycerid worms, which means the roles of the different tissues of the glycerid venom apparatus can now be examined in more detail.
Masters Project
This project will examine the composition and distribution of venom proteins and peptides in the recently re-described venom apparatus of glycerid polychaete worms using MALDI mass spectrometry imaging (MSI). MSI is a non-targeted imaging approach that directly detects and maps the distributions of molecules across tissue sections using MALDI mass spectrometry. The student will use state-of-the-art MSI methods and instrumentation to map both intact (top-down) and digested (bottom-up) venom components. They will also perform proteomic analyses of tissue liquid extractions and laser microdissections to generate complementary data on protein composition and tissue distribution. The student will then compare their results with existing venom proteomic and venom apparatus transcriptomic and spatial transcriptomic data to test hypotheses on the functional morphology of the glycerid venom system.
Main supervisor: Eivind A. B. Undheim, CEES, IBV
Co-supervisor: Tuula Nyman, Oslo University Hospital
References:
Ashwood LM, Undheim EAB, Madio B, Hamilton BR, Daly M, Hurwood DA, King GF, Prentis PJ (2021) Venoms for all occasions: the functional toxin profiles of different anatomical regions in sea anemones are related to their ecological function. Molecular Ecology 31: 866–883.
Kazandjian TD, Hamilton BR, Robinson SD, Hall SR, Bartlett KE, Rowley P, Wilkinson MC, Casewell NR, Undheim EAB (2022) Physiological constraints dictate toxin spatial heterogeneity in snake venom glands. BMC Biology 20: 1–14
Richter S, Helm, C, Meunier FA, Hering L, Campbell L, Drukewitz SH, Undheim EAB, Jenner RA, Schiavo G, Bleidorn C (2017) Comparative analyses of glycerotoxin expression unveil a novel structural organization of the bloodworm venom system. BMC Evolutionary Biology 17: 64.
