Investigating the relationship between amphotericin B and extracellular vesicles produced by Streptomyces nodosus

  • Samuel J. King

Western Sydney University thesis: Master's thesis

Abstract

The antifungal drug amphotericin B is made by Streptomyces nodosus and is released into culture broths at concentrations exceeding its solubility in water. The recent discovery of extracellular vesicles derived from Streptomyces species suggests that amphotericin B could be released from the biomass using this delivery system. This thesis identified a Streptomyces soil isolate through the construction of a phylogenetic tree based on 16S sequences. The soil isolate was used to develop methods to image Streptomyces extracellular vesicles using STEM, which were then used to examine whether S. nodosus produces extracellular vesicles. Initial co-localisation experiments using size fractionation indicated that amphotericin B was associated with fractions containing extracellular vesicles. Extracellular vesicles from the culture fluid of a mutant unable to produce amphotericin B, indicated that vesicle production was not dependent on amphotericin synthesis but may play a role in delivering other hydrophobic molecules.
Date of Award2017
Original languageEnglish

Keywords

  • amphotericin B
  • antifungal agents
  • drug delivery systems
  • systemic mycoses
  • extracellular vesicles

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