Environmental perception in motile diatoms

(WHEELER_EMBA19ARIES)

Environmental perception in motile diatoms

(WHEELER_EMBA19ARIES)

Project Description

Supervisors

Dr Glen Wheeler (Marine Biological Association of the UK)

Prof Graham Underwood (University of Essex Biological Sciences)

Dr Katherine Helliwell (MBA)

Prof Colin Brownlee (MBA)

 

Scientific background:

Estuaries are important marine habitats exhibiting high levels of biodiversity. Diatoms are single-celled marine algae that are major primary producers in estuarine environments, where their success is underpinned by their ability to glide, moving through the sediment in response to changes in light or nutrients. Although this process is central to diatom ecophysiology, little is known about the underlying signalling processes that allow diatoms to sense and respond to key environmental cues.

This project will examine how diatoms sense light, nutrients and other stimuli and translate these stimuli into motile responses. The overarching aim is to examine the mechanisms through which motile responses are determined by diatom physiology and therefore underpin their ecological success.

Gliding motility in diatoms is regulated by calcium signalling and we have recently developed techniques to measure cytosolic calcium in the model diatom Phaeodactylum tricornutum using genetically encoded fluorescent biosensors. Development of these exciting technologies and their application to other diatom species will be an important aspect of the project.

 Approach:

The project will use state of the art technologies to study cell signalling in diatoms in response to different environmental stimuli. The aims of the project will be 1) to determine the calcium-dependent signalling processes underpinning motility, 2) to examine the cellular mechanisms of motility acting downstream of calcium signalling, 3) to determine how cell physiology influences the nature of motile responses. The project will feature extensive use of live cell imaging, both video microscopy tracking of single cells and fluorescent microscopy of diatom cells expressing genetically encoded calcium reporters. The project will also employ the advanced molecular techniques now available in diatoms to generate strains expressing additional fluorescent biosensors or for targeted gene knockout of potential signalling pathways.

Training:

The project will offer extensive training opportunities in laboratory techniques, including algal growth and physiology, advanced microscopy (including single cell imaging) and molecular techniques including development of transgenic diatoms strains.

Person specification:

We are looking for a highly motivated student with a strong interest in algal biology and ecophysiology. The project will primarily suit candidates with a degree in biology, biochemistry and/or molecular biology but candidates with other relevant experience will also be considered.

The successful candidate will be registered for a PhD in the University of Essex’s School of Biological Sciences.

References

  • Helliwell K. E., Chrachri A., Taylor A., Koester J., Wharam S., Wheeler G., and Brownlee C. Novel classes of voltage-gated Na+ and Ca2+ channels play important signalling roles in unicellular eukaryotes. In review.
  • Wheeler G., Helliwell K. E., and Brownlee C. Calcium Signalling in Algae. Perspectives in Phycology. DOI: 10.1127/pip/2018/0082
  • Bondoc G., Heuschele J., Gillard J., Vyverman W. & Pohnert G.. Selective silicate-directed motility in diatoms. Nature Communications. Nature Communications 7:10550, (2016)
  • McLachlan DH, Underwood GJC, Taylor AR, Brownlee C (2012) Calcium release from intracellular stores is necessary for the photophobic response in the benthic diatom Navicula perminuta (Bacilariophyceae). Journal of Phycology 48, 675-681.
  • Bohórquez, J and McGenity, TJ and Papaspyrou, S and García-Robledo, E and Corzo, A and Underwood, GJC (2017) 'Different Types of Diatom-Derived Extracellular Polymeric Substances Drive Changes in Heterotrophic Bacterial Communities from Intertidal Sediments.' Frontiers in Microbiology, 8 (245). ISSN 1664-302X

Open for applications

Please apply by sending a CV (including contact details of two academic referees) and a cover letter explaining your motivation and suitability for the PhD.

They should be sent to Emma Revill  ariesapp@essex.ac.uk  by 8th Jan 2019