Microbial outer membrane vesicles: biological significance and biotechnological application

Project Description
This studentship involves the development of a systems-level understanding of extracellular decomposition engineered by micro-organisms via outer membrane vesicles (OMVs). Our model systems are OMV-mediated predation by the social soil bacterium Myxococcus xanthus and rumen bacterial degradation of forages. M. xanthus commonly exists as biofilms, which are defined as attached bacteria enveloped in extracellular polymeric substances (EPS). Indeed, we recently showed that plant-attached microbiota within the rumen also commonly occur as biofilms (Huws et al., 2013). Existence as a biofilm is paramount for effective digestion/predation due to the ability of the EPS to concentrate key enzymes. OMVs are bacterial-derived vesicles which form key components of the EPS (Schooling & Beveridge, 2006). OMVs are produced by bacteria for many purposes, from pathogenesis to viral-resistance, but universally act as transport devices filled with hydrolase enzymes and bioactive metabolites. Due to their relatively simple proteomes and metabolomes OMVs are ideal experimental subjects.

Recently we showed that M. xanthus co-operatively secretes digestive outer membrane vesicles (OMVs) which kill Escherichia coli, releasing nutrients for extracellular metabolism and consumption (Whitworth, 2011; 2012). Quantitative proteomics analysis of M. xanthus OMV composition, enzymatic assays of vesicle components and TEM imaging of vesicle secretion and killing have also been undertaken (Whitworth et al., 2012). Many secreted enzymes within the OMVs were shown to be involved in catabolism of prey biomolecules. Nonetheless OMVs and their importance within plant-associated biofilms in the rumen have been overlooked. This project will initially take lessons from what is known regarding M. xanthus OMVs and apply similar technology to study the biological relevance of OMVs to rumen systems biology. In addition to developing models of multi-compartment distribution of metabolism, a systems biology approach is needed to answer fundamental questions regarding spatio-temporal aspects of OMV action. For instance, how many OMVs are needed to kill an E. coli or degrade a plant cell wall, how quickly does vesicle fusion result in lysis, and how do environmental factors such as mixing affect OMV efficacy? Dependent on OMV constituents, the findings from this project may also have key implications for discovery of novel compounds for the biotechnological industry.

Thus the key aims of this studentship are to:
1. Characterise the vesicular components of the rumen.
2. Define the physiological functions of OMVs.
3. Assess the composition of rumen and myxobacterial vesicles.
4. Develop systems models of OMV-mediated degradation

This is an unique opportunity for an outstanding student to gain skills in general microbiology, ‘omics’ methods, along with bioinformatics and mathematical biology – an unusual and desirable skill set for a future career in research.

Supervisors: Dr Sharon Ann Huws (Main supervisor), Dr David Whitworth and Dr Chris Creevey
Animal and Microbial Sciences theme: http://www.aber.ac.uk/en/ibers/research/ams/
Dr Sharon Huws: http://www.aber.ac.uk/en/ibers/staff/staff_profiles/hnh/;
Dr David Whitworth: http://www.aber.ac.uk/en/ibers/staff/staff_profiles/dew/

"Candidates should have (or expect to achieve) a First Class or Upper second class honours degree and/or a masters degree
(or equivalent) in a relevant subject."

We encourage prospective candidates to contact the lead supervisor Dr Sharon Huws [Email Address Removed]; 01970 823202;
Dr Sharon Huws: http://www.aber.ac.uk/en/ibers/staff/staff_profiles/hnh/;

http://www.aber.ac.uk/en/ibers/opportunities-@-ibers/