Characterisation and evolution of ant venom

Background

Animal venoms are complex cocktails of bioactive polypeptides, known as toxins, that potently and selectively target important physiological processes in their victims. They have therefore attracted significant attention as rich sources of novel compounds with potential use as human therapeutics, agrochemicals, and molecular tools. Venom has emerged on over 100 independent occasions throughout the animal kingdom, and each of these venomous lineages has evolved its own biochemical arsenal of toxins through the modification of existing “housekeeping” proteins and peptides. As such, venoms are also great models for studying evolution of novelty and functional innovation.

However, the venoms of most venomous lineages remain largely or even completely unstudied. Surprisingly, one such group is Aculeata, or stinging hymenopterans, which includes bees, wasps, and ants. Among these, ants (Formicidae) are probably among the most familiar to most of us, yet their venoms have remained largely unexplored due in part to the widespread misconception that they have simple, primarily acid–based venoms. It is now clear that the majority of stinging ant venoms are composed primarily of a single, hyperdiverse family of peptide toxins called aculeatoxins (See figure for a recent example). Ant venoms thus represent large untapped resources of novel bioactive compounds which evolution histories remain virtually unexplored.


Masters Project

This project aims to characterise the toxin arsenal of a common species of stinging ant, Myrmica rubra, and examine its evolution using state of the art methods in evolutionary venomics. The student will generate comprehensive venom profiles using a combination of venom gland transcriptomics and mass spectrometry-based proteomic analyses of milked venom, while the evolution of toxin genes will be examined using comparative molecular and evolutionary analyses. Selected toxins will also be synthesised and screened for pharmacological activities by international collaborators. Together, these outcomes will provide new insights into the evolutionary processes that underlie the origin and functional diversification of one of the most convergent animal traits known, and potentially lead to the discovery of novel molecular tools.

Bildet kan inneholde: tekst, linje, organisme, diagram, parallell.
We previously demonstrated the venom of the giant Australian bull ant, Myrmecia gulosa, is composed almost exclusively of aculeatoxin peptides. (A) M. gulosa. (B) Total ion chromatogram of M. gulosa venom. (C) Venom apparatus of M. gulosa. (D) Venom component-encoding transcripts (that is, those encoding peptides detected in the venom itself) comprised 15.9% of total expression. Of these, transcripts encoding aculeatoxin peptides, MIITX2-Mg1a, MIITX3-Mg1a, and venom proteins comprised 93.0, 3.4, 3.3, and 0.3%, respectively, of venom component expression. EGF, epidermal growth factor. (E) Venom component-encoding transcripts (highlighted in red) are found exclusively in the highly expressed portion of the venom apparatus transcriptome, where they constitute most of the most highly expressed transcripts. Inset: Zoom showing the top 50 transcripts (with a linear scale on the y axis). The most highly expressed non-venom component-encoding transcripts are labeled [cytochrome c oxidase subunits 1 (COI), 2 (COII), and 3 (COIII)].
From Robinson et al., Science Advances, 2018, 4: eaau4640 (DOI: 10.1126/sciadv.aau4640).

 

Publisert 7. aug. 2020 20:33 - Sist endret 7. aug. 2020 20:33

Omfang (studiepoeng)

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