Applications of HS-AFM Imaging to Marine Microbial Life and its Environment

  • Christopher T Evans

Student thesis: Doctoral ThesisDoctor of Philosophy (PhD)

Abstract

This PhD project aims to exploit the capabilities offered by High-Speed Atomic Force Microscopy (HS-AFM) to characterise the interactions between coccolithoviruses (Emiliania huxleyi Virus, EhV) and their globally important coccolithophore hosts (Emiliania huxleyi, E. hux), as well as investigating application of HS-AFM to related environmental samples and beyond.
A selection of marine science focussed examples are explored with HS-AFM centred towards developing protocols and methodology applicable to imaging and collecting data from the microalgae-virus system. These samples also test applying HS-AFM to a representation of the environmental niche inhabited by the model system. This includes producing large Scanning Electron Microscopy (SEM) sized area scans whilst maintaining high resolution Atomic Force Microscopy (AFM) information in both air and aqueous environments. Through development of the liquid cell, HS-AFM provides capability to visualise individually unique particles, surfaces and structures under environmentally and physiologically relevant conditions.
Structural characterisation of EhV is investigated, being critical for following experiments involving both viruses and cell membranes. The development of a novel 3D printed array for cell immobilisation facilitates analysis of E. hux cell membranes.
EhV is first introduced to supported lipid bilayers (SLBs) generated from E. hux cell membrane components with transient viral binding of EhV to E. hux derived SLBs imaged in a liquid environment. Next, binding of EhV to live E. hux cells prepared in 3D cell arrays with contact mode HS-AFM in a physiologically relevant aqueous environment is presented.
Unique data is collected utilising HS-AFM technology, on samples and in a field traditionally lacking access to, or history, of such techniques. This data has intrinsic value that is explored whilst maintaining project focus of characterising the interactions between coccolithoviruses and their coccolithophore hosts.
Atomic force microscopy may have been overlooked as a structural tool, but with speed increases shows promise as a method for dynamic observations. In my opinion, HS-AFM is a useful tool for studying host, virus and the infection process in a dynamic way that is not applicable to other approaches, as well as many alternative experimental hypotheses surrounding the microalgal-virus environment and system.
Date of Award23 Mar 2021
Original languageEnglish
Awarding Institution
  • The University of Bristol
SupervisorJohn C C Day (Supervisor), Loren M Picco (Supervisor), Oliver D Payton (Supervisor) & Mike Allen (Supervisor)

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