Information is also available at Dr Overton’s research group website.
Applied molecular microbiology, Microbial flow cytometry, Recombinant protein production, Bacterial responses to stress.
Research activities are in several broad areas, all focusing on the use of information about the molecular microbiology and physiology of bacteria to develop processes that either utilise them as tools for the production of high-value products or eliminate them from foodstuffs. Stress responses and regulatory events in both types of process are linked, so synergy is achieved in investigating both areas simultaneously. Running through all research areas are the techniques of flow cytometry and molecular biology.
Engineering biofilms for bioprocesses
In collaboration with Mark Simmons (UoB) and Rebecca Goss (St. Andrews), this major BBSRC-funded project aims to generate and utilise engineered biofilms for biotransformation reactions to produce small molecules used in pharmaceutical production. Although more usually a problem for the process industries, biofilms offer many advantages over planktonic cells for biotransformation and biocatalysis reactions. This project is developing tools, from the molecular to the process scale, in order to use biofilms as immobilised catalysts for fine chemical biotransformations.
Recombinant protein production
A TSB and BBSRC-funded Knowledge Transfer Partnership in collaboration with Cobra Biologics is currently investigating production of recombinant proteins in bacterial hosts. This project expands upon previous BBSRC-funded research and PhD projects. A major aim of this work is to develop methods by which recombinant protein production bioprocesses can become more predictable and failure rates can be decreased. Further details on the project are available in a press release.
An ERA-IB grant focuses on the development of novel methods to isolate high-value products from horse serum. This project (named ProSeCa) is in collaboration with the Karlsruhe Institute of Technology, the Technical University of Denmark, SENOVA GmbH and fzmb GmbH. Work in Birmingham focuses on the manufacture and use of novel magnetic particles for separation processes using biological systems.
PhD students are also investigating the area of recombinant protein production in E. coli and the simultaneous optimisation of intensified fermentation conditions and product release, capture and purification strategies.
Research funded by EU FP7 in collaboration with Mike Jenkins in Materials and Metallurgy and Gary Leeke in Chemical Engineering as well as other European partners is investigating biopolymer production. More details about the aims of the project are available on the ISA-PACK project website.
Bacterial responses during food and waste processing
An Innovate UK-funded project with Gary Leeke and SERE-Tech Innovation is currently investigating novel methods of bacterial inactivation in collaboration with industrial partners.
In collaboration with Kostas Gkatzionis, two PhD students are currently investigating bacterial responses to novel processing strategies using flow cytometry as a rapid analytical technique.
Microbial flow cytometry techniques
Flow cytometry is an extremely powerful technique for interrogating single cells within a population, and is used as an integral part of many of the projects above. In addition, collaborative research both within the University of Birmingham (the Schools of Biosciences and Chemical Engineering, the Medical School and the Centre for Systems Biology) and with other Universities seeks to extend the technique to answer research questions in the areas of molecular microbiology, cell biology, bioprocessing and environmental microbiology in both bacteria and yeast.
These methods are made possible using the latest equipment, which was acquired through a BBSRC REI grant in 2007. Dr Overton is interested in developing new collaborations in this area.
Google scholar: http://scholar.google.co.uk/citations?user=tF_eBKEAAAAJ
Selected journal articles
Chaudhari RD, Stenson JD, Overton TW, Thomas CR. (2012) Effect of Bud Scars on the Mechanical Properties of Saccharomyces cerevisiae Cell Walls. Chemical Engineering Science 84: 188-196
Foulkes, JM, Winn, M, Perni, S, Simmons, MJH, Overton, TW & Goss, RJM. (2012) Biofilms and their Engineered Counterparts: a new Generation of Immobilised Biocatalysts. Catalysis Science and Technology DOI: 10.1039/C2CY20085F
Vizcaino-Caston, I, Wyre, C and Overton, TW. (2012) Fluorescent proteins in microbial biotechnology – new proteins and new applications. Biotechnology Letters 34: 175-186.
Tsoligkas, AN, Bowen, J, Winn, M, Goss, RJM, Overton, TW and Simmons, MJH. (2012) Characterisation of spin coated engineered Escherichia coli biofilms using atomic force microscopy. Colloids and Surfaces B: Biointerfaces 89: 152-160.
Whitehead, RN, Kemp, CL, Overton, TW and Webber, MA. (2011) Exposure of Salmonella enterica serovar Typhimurium to high level biocide challenge can select for multidrug resistant mutants in a single step. PLoS ONE 6(7): e22833 doi:10.1371/journal.pone.0022833.
Tsoligkas, AN, Winn, M, Bowen, J, Overton, TW, Simmons, MJH, and Goss, RJM. (2011) Engineering Biofilms for Biocatalysis. ChemBioChem 12: 1391-1395.
Li, Y, Hopper, A, Overton, T, Squire, DJ, Cole, J, and Tovell ,N. (2010) Organisation of the electron transfer chain to oxygen in the obligate human pathogen, Neisseria gonorrhoeae: roles for cytochromes c4 and c5, but not cytochrome c2, in oxygen reduction. Journal of Bacteriology 192: 2395-406.
Yanina Sevastsyanovich, Y, Alfasi, S, Overton, T, Hall, R, Jones, J, Hewitt, C, and Cole, J. (2009) Exploitation of GFP fusion proteins and stress avoidance as a generic strategy for the production of high-quality recombinant proteins.FEMS Microbiology Letters 299 86–94.
Overton, TW, Justino MC, Li Y, Baptista JM, Melo AM, Cole JA, and Saraiva LM. (2008) Widespread distribution in pathogenic bacteria of di-iron proteins that repair oxidative and nitrosative damage to iron-sulfur centers.Journal of Bacteriology 190 2004-132004-13.
Overton, TW, Whitehead, R, Li, Y, Griffiths, L and Cole, J. (2008) Sense and nonsense from whole genome microarray data in the analysis of microbial physiology. Biotechnologia 80: 15-30
Filenko, N, Spiro, S, Browning, DF, Squire, D, Overton, TW, Cole, J and Constantinidou, C. (2007) The NsrR regulon of Escherichia coli K-12 includes genes encoding the hybrid cluster protein and the periplasmic, respiratory nitrite reductase. Journal of Bacteriology 189 4410-7.
Whitehead, RN, Overton, TW, Snyder LAS, McGowan, S, Smith, H, Cole, JA and Saunders, NJ. (2007) The small FNR regulon of Neisseria gonorrhoeae: comparison with the larger E. coli FNR regulon and interaction with the NarQ-NarP regulon. BMC Genomics 8:35.
Nilavongse, A, Brondijk, THC, Overton, TW, Richardson, DJ, Leach, E and Cole, JA (2006) The NapF protein of the Escherichia coli periplasmic nitrate reductase system: demonstration of a cytoplasmic location and interaction with the catalytic subunit, NapA. Microbiology 152 3227-3237 3227-3237.
Overton, TW, Whitehead, RN, Li, Y, Snyder, LAS, Saunders, NJ, Smith, H and Cole, JA. (2006) Coordinated regulation of the Neisseria gonorrhoeae truncated denitrification pathway by the nitric oxide-sensitive repressor, NsrR, and nitrite-insensitive NarQ-NarP. truncated denitrification pathway by the nitric oxide-sensitive repressor, NsrR, and nitrite-insensitive NarQ-NarP. Journal of Biological Chemistry 281 33115-33126.
Constantinidou, C, Hobman, JL, Griffiths, L, Patel, MD, Penn, CW, Cole, JA and Overton, TW. (2006) A reassessment of the FNR regulon and transcriptomic analysis of the effects of nitrate, nitrite, NarXL and NarQP as Escherichia coli K-12 adapts from aerobic to anaerobic growth. Journal of Biological Chemistry 281 4802-15.
Turner, SM, Overton, T, Moir, JW & Cole, JA (2005). Mutational and biochemical analysis of cytochrome c', a nitric oxide-binding lipoprotein important for adaptation of Neisseria gonorrhoeae to oxygen-limited growth. Biochemical Journal 388 545-53.
Spreadbury, CL, Pallen, MJ, Overton, T, Behr, MA, Mostowy, S, Spiro, S, Busby, SJ & Cole, JA. (2005) Point Mutations in the DNA- and cNMP-Binding Domains of the Homologue of the cAMP Receptor Protein (CRP) in Mycobacterium bovis BCG: Implications for the Inactivation of a Global Regulator and Strain Attenuation. Microbiology 151 547-446.
Grainger, D, Overton, T, Hobman, JL, Constaninidou, C, Tamai, E, Wade, JT, Struhl, K, Reppas, N, Church, G & Busby, SJW (2004). Genomic studies with Escherichia coli MelR protein: applications of chromatin immunoprecipitation and microarrays. Journal of Bacteriology 186 (20) 6938-43.
Overton, TW. (2012) Flow cytometry of Yeasts and Fungi. In Wilkinson, M (ed.) Microbial Flow Cytometry. Caister Academic Press, UK.
Clark, VL Isabella, VM, Barth, K and Overton, TW. (2010) Regulation and Function of the Neisserial Denitrification Pathway: Life with Limited Oxygen. In Genco, C and Wetzler, L (eds.) Neisseria: Molecular Mechanisms of Pathogenesis. Caister Academic Press, UK.