Botany Main Building, Room G06
Tel +64 3 479 7578
Fax +64 3 479 7583
tina.summerfield@otago.ac.nz

Research Interests

Cyanobacterial diversity, genetics and ecophysiology, the potential of cyanobacteria as a renewable energy source and cyanobacterial symbioses.

Teaching Involvement

Current Research

Our research is focused on understanding the diversity and metabolic flexibility of cyanobacteria. These microbes are found in almost all environments on Earth. They are an excellent model system for the study of photosynthesis, nitrogen assimilation, circadian rhythms, and response to environmental stresses and have potential as a renewable energy source, for example many strains are capable of hydrogen production. Less than 20% of described species have been cultured, indicating the potential of cyanobacteria remains to be discovered.

Please contact me if you are interested in research projects in any of these areas.

Cyanobacterial hydrogen production
We are currently investigating the ability of New Zealand cyanobacteria to produce hydrogen. Through our collaboration with Dr Susie Wood at the Cawthron Institute we have access to many NZ cyanobacterial strains and are now assessing their capacity to produce hydrogen.

The Photosynthetic electron transport chain under low oxygen conditions
We have identified changes in the photosynthetic electron transport chain under low oxygen conditions that are associated with hydrogen production. We are investigating the impact of these changes on photosynthetic performance and hydrogen production.

Cyanobacterial symbioses
Cyanobacteria form symbiotic associations with plants and fungi. We are studying cyanolichens, in particular the mode of cellular communication between the symbiotic partners and how this alters photosynthetic metabolism.

Toxic cyanobacteria
In collaboration with Dr Susie Wood and Dr Lesley Rhodes at the Cawthron Institute we are examining the impact of toxin-producing cyanobacteria on Pacific Oysters. A stipend is available for a Masters student to work on this project.

 

Selected Publications

Summerfield TC, Nagarajan S, Sherman LA 2010. Gene expression under low oxygen conditions in the cyanobacterium Synechocystis sp. PCC 6803 demonstrates Hik31-dependent and Hik31-independent responses. Microbiology accepted September 2010

Shcolnick S, Summerfield TC, Reytman L, Sherman LA, Keren N 2009. The mechanism of iron homeostasis in the unicellular cyanobacterium Synechocystis sp. PCC 6803 and its relationship to oxidative stress. Plant Physiology 150, 2045-2056.

Toepel J, McDermott J, Summerfield TC, Sherman LA 2009. Transcriptional analysis of the unicellular, diazotrophic cyanobacterium Cyanothece sp. ATCC 51142 grown under short day/night cycles. Journal of Phycology, 45, 610-620.

Summerfield TC, Toepel J, Sherman LA 2008. Low-oxygen induction of normally cryptic psbA genes in cyanobacteria. Biochemistry 47, 12939-12941.

Summerfield TC, Sherman LA 2008. Global transcriptional response of the alkali-tolerant cyanobacterium Synechocystis sp. strain PCC 6803 to a pH 10 environment. Applied and Environmental Microbiology 74, 5276-5284.

Toepel J, Welsh E, Summerfield TC, Pakrasi H, Sherman LA 2008. Differential transcriptional analysis of the cyanobacterium Cyanothece sp. strain ATCC 51142 during light-dark and continuous-light growth. Journal of Bacteriology 190, 3904-3913.

Summerfield TC, Sherman LA 2007. The role of sigma factors in controlling global gene expression in light/dark transitions in the cyanobacterium Synechocystis sp. strain PCC 6803. Journal of Bacteriology 189, 7829-7840.

Summerfield TC, Eaton-Rye JJ, Sherman LA 2007. Global gene expression of a ΔPsbO:ΔPsbU mutant and a spontaneous revertant in the cyanobacterium Synechocystis sp. strain PCC 6803. Photosynthesis Research 94, 265-274.

Singh AK, Summerfield TC, Li H, Sherman LA 2006. The heat shock response in the cyanobacterium Synechocystis sp. strain PCC 6803 and regulation of gene expression by HrcA and SigB. Archives of Microbiology 186, 273-286.

Summerfield TC, Eaton-Rye JJ 2006. Pseudocyphellaria crocata, P. neglecta and P. perpetua from the Northern and Southern Hemispheres are a phylogenetic species and share cyanobionts. New Phytologist 170, 597-607.

Summerfield TC, Winter RT, Eaton-Rye JJ 2005. Investigation of a requirement for the PsbP-like protein in Synechocystis sp. PCC 6803. Photosynthesis Research 84, 263-268.

Summerfield TC, Shand JA, Bentley FK, Eaton-Rye JJ 2005. PsbQ (Sll1638) in Synechocystis sp. PCC 6803 is required for photosystem II activity in specific mutants and in nutrient-limiting conditions. Biochemistry 44, 805-815.

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