Cell Biology of Marine Protists
Despite playing a pivotal role in our oceans, relatively little is known about the cell biology of marine protists, a large and diverse group of unicellular organisms which includes both autotrophic and heterotrophic groups. Research in my lab has focussed on the cell biology of diatoms and coccolithophores, two of the most significant groups of phytoplankton with respect to ocean primary productivity and marine biogeochemical cycles. This work has revealed that these organisms, regarded until recently to be essentially plant-like algae, possess a variety of animal-like membrane transport properties. This is supported by the recent availability of genome sequence data which confirms the presence of groups of animal-like genes including those for metabolism, ion channels and transporters. These genes have most likely been acquired from the heterotrophic ancestral host during the secondary endosymbiotic evolutionary origin of the heterokont lineage.  To what degree such animal-like properties underpin the environmental physiology and contribute to the global success of these marine autotrophic protists is a driving question in our research.  While a comparative approach among a range of phytoplankton and other heterotrophic marine protists is the longer-term goal of our research, work is currently centred on identifying and functionally characterising ion transport mechanisms associated with signalling and homeostasis in diatoms, coccolithophores and foraminifera.  To address these questions we use a variety of conventional and novel cell physiology techniques including electrophysiology and high resolution imaging combined with molecular approaches. Current research includes the following topics:

• Characterisation of phytoplankton membrane transporters
• Transport processes that underpin cellular homeostasis in calcifying coccolithophores
• Diatom membrane physiology and signalling
• Membrane physiology of harmful algae and marine biotoxins
• Cellular physiology of foraminifera.

Selected publications (*graduate students)
Taylor, AR. *Russell MA, *Harper G, Collins T, Brownlee C (2007). Dynamics of the formation and secretion of hetercoccoliths by Coccolithus pelagicus (ssp Braarudii). European Journal of Phycology 42:125-136

*Thompson, S.E.M., Callow, J.A., Callow, M.E., Wheeler, G.L., Taylor, A.R., Brownlee, C (2007). Membrane recycling and calcium dynamics during settlement and adhesion of zoospores of the green alga Ulva linza.  Plant Cell and Environment 30: 733-744

Bloom AJ,  Frensch J & Taylor AR (2006) Influence of inorganic nitrogen and pH on the elongation of maize seminal roots. Annals of Botany 97: 867-873

Wheeler G.L., Tait K., Taylor AR, Brownlee C., Joint I. (2006) Acyl-homoserine lactones modulate the settlement rate of zoospores of the marine alga, Ulva intestinalis, via a novel chemokinetic mechanism. Plant Cell and Environment 29: 608-618

Brownlee, C. & Taylor, A.R., (2004). Calcification in coccolithophores: A cellular perspective. In Coccolithophores-from molecular processes to global impact (ed. H.R. Thierstein and J.R. Young), Springer, Germany, pp. 31–49.

Davey, M., Suggett, D., Geider, R.C. & Taylor, A.R., (2003). Plasma membrane redox activity: effect of iron limitation and interaction with photosynthesis. Journal of Phycology, 39, 1132–1144.

Taylor, A.R. & Brownlee, C., (2003). A novel inwardly rectifying chloride current regulates membrane potential in the marine phytoplankton Coccolithus pelagicus. Plant Physiology, 131, 1391–1400.

Bloom, A.J., Meyerhoff, P.A., Taylor, A.R. & Rost, T.L., (2003). Root development and absorption of ammonium and nitrate from the rhizosphere. Journal of Plant Growth Regulation, 21, 416–431.

*Coelho, S., Taylor, A.R., Sousa-Pinto, T., Ryan, K., Brown, M.T. & Brownlee, C., (2002). Spatio-temporal patterning of reactive oxygen production and calcium wave propagation in Fucus rhizoid cells. Plant Cell, 14, 2369–2381.

Brownlee, C. & Taylor, A.R., (2002) Algal Calcification and Silification in Encyclopedia of Life Sciences, http://www.els.net. London: Nature Publishing Group.

*Berry, L., Taylor, A.R., Lucken, U., Ryan, K.P. & Brownlee, C., (2002). Calcification and inorganic carbon acquisition in coccolithophores. Functional Plant Biology, 29, 289–299.