Key Research Interests

I am a molecular microbiologist who is interested in how a broad range of microbes, both Prokaryotic and Eukaryotic, participate in biogeochemical cycling. My research group focuses on the specific mechanisms that allow such organisms to synthesise and breakdown key biological molecules and importantly regulate these processes as to allow them to sense and respond to environmental cues.


Current Research Projects: 

  • Identification and characterisation of the ways in which microbes breakdown the anti-stress molecule dimethylsulphoniopropionate (DMSP) that is made by many marine phytoplankton, macroalgae and a few angiosperms. This microbial DMSP catabolism is central to the global sulphur cycle, can affect both the local and global climate and is an important signaling cue to many higher organisms. (With Prof. AWB Johnston, funded by NERC and BBSRC
     
  • How and why do Eukaryotic Algae make DMSP? As well as studying the catabolism of DMSP we are also identifying the ways in which algae make the most abundant sulphurous molecule in the oceans and importantly why do they do so. Surprisingly the exact function of DMSP remains unclear. (With Dr Thomas Mock, funded by NERC)
  • Studies of mechanisms involved in metal transport and metal responsive gene regulation in Rhizobium and marine proteobacteria. (With Prof. AWB Johnston, funded by BBSRC)
  • Analysis of Carbon Monoxide Dehydrogenase enzymes in marine roeobacters that serve to detoxify this respiratory inhibitor. (With Dr Michael Cunliffe at the Marine Biological Association)
  • A study into denitrification in marine roseobacters. We are interested in the expression, regulation and enzymology of a suit of denitrification genes that exist in these microaerobic organisms. (with Dr Andrew Gates)


Life in our Research Group: 

As a research group we use molecular genetics to study i. how a wide range of microbes catabolise dimethylsulfoniopropionate (DMSP), the most abundant sulphur-containing anti-stress molecule in the oceans; and more recently ii. how Eukaryotic phytoplankton, macroalgae and a few marine plants that make DMSP do so and importantly why. The application of molecular genetics to the field DMSP research by us and notably by Mary Anne Moran’s group at the University of Georgia has been responsible for discovering the mechanisms by which many marine bacteria and some fungi breakdown DMSP generating the important gases DMS and Methanethiol. Our studies into the generation of DMS from DMSP through the enzyme products of the ddd genes has found that there is remarkable diversity in the ways in which different microbes do this this (six different Ddd enzymes have identified thus far); that the ddd genes are the subject of widespread horizontal gene transfer; and that these enzymes appear to have differing physiological roles depending on the organism that contains them (potentially involved in growth, respiration or signaling processes). Quite aside from needing to understand the role played by DMSP in primary producers, studies into its catobolism by microbes are important because DMS is a significant chemo-attractant for marine animals, its oxidation products are “cloud condensation nuclei” that initiate cloud formation over the oceans and it and methanthiol are a key intermediates in the global sulphur cycle .

Our other main running research theme in the lab revolves around how microbes, both marine and terrestrial, acquire and regulate the acquisition of essential transition metals, such as iron and manganese, from their environment. In the past we have worked on how this is carried out in Rhizobia, a terrestrial alpha-proteobacterium that forms nitrogen fixing symbiosis with leguminous plants. As a result of this work we found that alpha-proteobaterial Fe homeostasis does not conform to the conventional Fur global regulator system. In model organisms, such as E. coli, Fur represses many genes in response to iron availability. Instead we found that two global regulators, called Irr and RirA, work in concert to control the expression of many genes under conditions of iron availability in the alpha’s. Using biochemistry coupled to molecular genetics we found that Irr regulates gene expression in response to haem availability, whereas RirA is an iron-sulphur containing regulator that represses in the presence of its co-factor.

Since aphaproteobacteria are incredibly abundant in the ocean and through a combination of genomics, bioinformatics, transcrptomics coupled to molecular genetics we are beginning to address the way in which these marine bugs both acquire their essential metals and control this acquisition. It is surprising how little molecular biology is carried out on marine systems despite their importance and abundance.

As detailed in our “Current Research Topics” we have other projects on going, but these are very much in their infancy. All our lab projects are microbiological based involve molecular genetics, genomics and bioinformatics. Some of our projects involve metagenomics molecular ecology, metabolomics and biochemistry.

We pride ourselves on having a friendly, but, hardworking lab atmosphere. Everybody cares for their lab colleagues and actively participates in weekly lab meetings

Our work benefits from collaboration with colleagues in the Norwich Research Park (Nick Le Brun, Charles Brearley, Thomas Mock, Lionel Hill, Tony Davy, Phil Page, Phil Poole, Arnoud van Vliet, Yohan Chan, Allan Downie and Paul Nicholson) and elsewhere (such as Andrew Lang, Jeffrey Waller, Chris Dupont, Krystal Rypien, Michael Steinke, Dmitry Rodionov, Steve Giovanonni, Colin Murrell and Hendrik Schaefer). 

PhD Positions

Click here for current PhD opportunities in Biological Sciences. But feel free to email me to discuss projects outside these areas and alternative sources of funding.

Postdocs and Fellows: 

I welcome enquiries from motivated postdocs who are interested in applying for their own funding to come and work in my lab. 

 

 

 

 

 

 

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