Brent J Sinclair
BSc(Hons) (1996, Otago)
PhD (2001, Otago)

Postdoctoral Scholar

Background
I did my BSc(Hons) and PhD research in Zoology with Dr David Wharton at the University of Otago, New Zealand, where I worked on the ecology and physiology of alpine and Antarctic arthropods. I then moved on to a three-year postdoc in the SPACE Lab at the University of Stellenbosch, South Africa, where I worked on many aspects of the evolutionary and ecological physiology of arthropods in a number of habitats, including the Cederberg and Drakensberg mountains, sub-Antarctic Marion Island, and Cape Hallett on the Antarctic Continent.

A comparative approach to the cryopreservation of the model organism Drosophila melanogaster
Drosophila melanogaster is one of the most important animal models for the investigation of genetics, molecular biology, neurobiology, development and a number of human diseases. Lines of most important animal models are cryopreserved as embryos, but reliable cryopreservation is not currently available for D. melanogaster, which means that important lines and mutants are maintained in live culture. Live cultures are prone to genetic drift, further mutation, bottlenecking, inbreeding and extinction, all of which can compromise the utility of stocks. In addition, stocks are personpower-intensive and expensive to maintain, resulting in increasing closures of stock centers and consequent loss or consolidation of stocks. A recent review in Nature Reviews Genetics predicted a future requirement for the maintenance of >150,000 lines of D. melanogaster – more than three times the current worldwide capacity of funded stock centers. Traditional cryopreservation techniques (for example, those published for D. melanogaster embryos in the early 1990s) utilize a permeabilization, cryoprotectant loading and vitrification protocol based on methods developed for preserving mammalian cells and embryos; however, the practicality and success of these methods was extremely low. In collaboration with Drs Steve Roberts and Allen Gibbs and Dr Vladimir Kostal (Czech Academy of Sciences), I propose taking a comparative approach to cryopreservation. Many dipteran larvae survive freezing, including at least two drosophilids. We will characterize the responses of D. melanogaster to low temperature rearing, acclimation and exposure, and screen larvae of a number of Drosophila species for exceptional tolerance to chilling or freezing. We will then conduct comparative studies on the physiological and biochemical differences between species whose larvae do and don’t survive freezing, with a view to manipulating the factors contribution to freeze tolerance in D. melanogaster, perhaps ultimately leading to a method of cryopreservation. Although this project essentially represents an application of comparative physiology, it also promises to answer a number of intriguing evolutionary questions, including the key question of the reasons why one insect is able to survive freezing and another cannot.

Mechanisms of Rapid Cold-Hardening in Insects
Rapid cold-hardening (RCH) is a process whereby an insect’s tolerance to a low temperature is improved by a brief prior exposure to a milder cold temperature. In other words, if you grab some insects (for example the Fynbos chrysomelid beetle Chirodica chalcoptera from South Africa), and expose them to -10.1 °C about 30% of them will survive. On the other hand, if you first expose them to 0 °C for 2 hours, survival increases to 80% or more. Although RCH has been demonstrated in a large number of species of arthropods, the mechanisms are not understood, and there is no hypothetical model to explain the action of the RCH response. My current research uses the fruit fly Drosophila melanogaster as a model species that shows the RCH response. I am using proteomic and genomic tools to generate a hypothesis for the mechanisms behind RCH.

Curriculum Vitae

Selected Publications

Sinclair, B.J. & Roberts, S.P. (2005) Acclimation, shock and hardening in the cold. Journal of Thermal Biology 30: 557-562.

Sinclair, B.J. & Chown, S.L. (2005) Caterpillars benefit from thermal ecosystem engineering by Wandering Albatrosses on sub-Antarctic Marion Island. Biology Letters DOI: 10.1098/rsbl.2005.0384.

Sinclair, B.J. & Chown, S.L. (2005) Climatic variability and hemispheric differences in insect cold tolerance: Support
from southern Africa. Functional Ecology 19: 214-221.

Sinclair, B.J. & Chown, S.L. (2005) Deleterious effects of repeated cold exposure in a sub-Antarctic caterpillar. Journal of Experimental Biology 208: 869-879.

Chown, S.L., Sinclair, B.J., Leinaas, H.P. & Gaston, K.J. (2004) Hemispheric asymmetries in biodiversity – A serious matter for ecology. PLoS Biology. DOI: 10.1371/journal.pbio.0020406

Klok, C. J., Sinclair, B. J. & Chown, S.L. (2004) Upper thermal tolerance and oxygen-limitation in terrestrial arthropods. Journal of Experimental Biology 207: 2361-2370.

Sinclair, B.J., Klok, C.J & Chown, S.L. (2004) Metabolism of the sub-Antarctic caterpillar Pringleophaga marioni during cooling, freezing and thawing. Journal of Experimental Biology 207: 1287-1294.

Sinclair, B.J., Marshall, D.J., Singh, S., & Chown, S.L. (2004) Cold tolerance of Littorinidae from Southern Africa: Intertidal snails are not constrained to freeze tolerance. Journal of Comparative Physiology B 174: 617-624.

Sinclair, B.J., Klok, C.J., Scott, M.B., Terblanche, J.S. & Chown, S.L. (2003) Diurnal variation in supercooling points of three species of Collembola from Cape Hallett, Antarctica. Journal of Insect Physiology 49: 1049-1061.

Sinclair, B.J., Vernon, P., Klok, C.J. & Chown, S.L. (2003) Insects at Low Temperatures: An Ecological Perspective. Trends in Ecology and Evolution 18: 257-262.

Sinclair, B.J., Addo-Bediako, A. & Chown, S.L. (2003) Climatic variability and the evolution of insect freeze tolerance. Biological Reviews 78: 181-195.

Sinclair, B.J. (2001) Biologically relevant environmental data: Macros to make the most of microclimate recordings. CryoLetters 22: 125-134.

Sinclair, B.J. (2001) Field Ecology of Freeze-Tolerance: Interannual variation in cooling rates, freeze-thaw and thermal stress in the microhabitat of the alpine cockroach Celatoblatta quinquemaculata Oikos 93: 286-293.

Sinclair, B.J. (1999) Insect cold tolerance: How many kinds of frozen? European Journal of Entomology 96: 157-164.