Giles E. Duffield Royal Society University Research Fellow Ph.D. 1997, University of Cambridge

The molecular basis of the mammalian circadian clock: In Vivo and in vitro tissue culture techniques are being employed to examine the molecular mechanisms underlying the central circadian oscillator in the rodent. Studies have revealed that circadian rhythmicity is intrinsic to the individual cells comprising the central circadian clock, the suprachiasmatic nucleus (SCN), and that orthologues of the Drosophila period gene and other related genes may be central components of the cellular clock. Studies are underway to evaluate the role of these putative clock genes in the organization of the central oscillator, and to identify novel molecules relevant to cellular clock function. These studies are supported by the Royal Society, the Wellcome Trust and the NIMH.

Ontogeny of the circadian clock: Dysfunction of the circadian clock may underlie several disease states, including Seasonal Affective Disorder, and sleep disorders. My PhD thesis work concentrated on the development of the circadian cock, the suprachiasmastic nucleus (SCN) of the hypothalamus. In particular, the synchronization of the neonatal circadian clock by cues derived from the mother, and the development of the light synchronizing pathway which allows the ambient light-dark cycle to influence synchronization of rhythms in the mature mammal. A combination of neuroanatomical, biochemical and behavioral approaches in the rodent were used to characterize maternal-entrainment mechanisms and the neuronal changes within the biological clock at key developmental stages. Results have revealed a role for maternal cues prenatally. I have provided neuroanatomical and biochemical evidence for this system in the postnatal rodent. Since completing the PhD my recent experiments have demonstrated a loss of dopaminergic influence and a continued effect of melatonin on adult circadian entrainment, and have examined the role of the transcription factor pCREB in various entrainment pathways within the SCN. These studies were supported by the Medical Research Council and the Wellcome Trust.

[Immunocytochemical staining of the developing suprachiasmatic nuclei]

Ecology and Conservation of Bolivian Psitticidae: I have been working in Bolivia on a part-time basis over the last seven years. In 1992, I was a member of a team from Nottingham University, which carried out an ornithological survey of the Beni Biosphere Reserve, and concentrated on ascertaining the conservation status of several international and locally threatened species, including parrots and cracids. Between 1994 and 1995, I was a research associate with the University of Nottingham on a project studying the ecology and conservation of forest island faunas at the same reserve (http://www.earthwatch.org/). This was funded by EarthWatch and the Dept. Environment, UK (Darwin Initiative). My present interest is in the ecology and conservation issue associated with the community ecology of macaws in the Beni Department of Bolivia, in particular the threatened and endemic Blue-throated macaw, Ara glaucogularis. My interest in this particular species has been long-term: in 1992, the location of this species was unknown, and ascertaining its conservation status was a focus for the ornithological survey at the Beni Biosphere Reserve. From 1995 to present, I have been working with the Bolivian conservation organization Association Armonia (Birdlife International partner for Bolivia) on a conservation and research program (headed by Alan Hesse since 1993). The population and distribution study of Ara glaucogularis reveals alarmingly low numbers of birds sparsely distributed over a 18,000 square kilometer area of lowland Bolivia. A management plan is now being implemented with local education being a central component. However, even now very little is known of the macaw's natural behavior and ecology (see Psittascene May 1997 9: 10-11). The work continues to be supported primarily by the Loro Parque Foundation. Additional support has been provided by various organizations, including British Airways Assisting Conservation, Sidney Sussex College, Cambridge, and Cambridge Philosophical Society.

[The endangered Blue-throated macaw, Ara glaucogularis, in its native habitat of lowland Bolivia and in captivity]

[Local education and raising awareness is central to the conservation program of Association Armonia]

Biography

I should assume that you have ventured this far because you are interested in one of my two disparate fields of research; circadian biology and conservation and ecology of parrots. I am originally from Yorkshire, England (born in Leeds, 1971), and lived for many years in Doncaster (yep, that once prosperous railway and coal-mining community close to Sheffield). I studied Zoology at Nottingham University (1989-1992) before arriving at Cambridge University to undertake PhD (1993-1997) and postdoctoral research (1997-1998) in chronobiology in the laboratories of Francis Ebling and Michael Hastings. I joined the joint laboratories of Jay Dunlap and Jennifer Loros in early 1999 to conduct studies on the molecular basis of the mammalian circadian clock.

Selected Bibliography

Duffield, G.E., Watson, N.P., Mantani, A., Peirson, S.N., Loros, J.J., Israel, M.A. and Dunlap, J.C. (2006) A role for the Id2 gene in regulating photic entrainment of the mammalian circadian system; under review.

Peirson, S.N., Butler, J.N., Duffield, G.E., Takher, S., Sharma, P. and Foster, R.G. (2006) Murine clock gene expression in the suprachiasmatic nuclei, retin, liver and heart differe markedly in their phases, amplitudes and båsal levels of expression; under review.

Duffield, G., Loros, J.J., and Dunlap, J.D. (2005) Analysis of circadian output rhythms of gene expression in neurospora and mammalian cells in culture. Methods Enzymology 393:315-341. Invited paper for edition on Circadian Rhythms.

Duffield, G.E. (2003) DNA microarray analyses of circadian timing (Invited Review, 'Young Investigator's Perspectives'). Journal of Neuroendocrinology 15:991-1002.

Nowrousian, M., Duffield, G.E., Loros, J.J. and Dunlap, J.C. (2003) The frequency gene is required for temperature-dependent regulation of many clock-controlled genes in Neurospora crassa. Genetics 164:923-933.

Duffield, G.E., Best, J.D., Meurers, B.H., Bittner, A., Loros, J.J. and Dunlap, J.C. (2002) Circadian programs of transcriptional activation, signaling, and protein turnover revealed by microarray analysis of mammalian cells. Current Biology 12:551-557, April 3 (cover article).

Hesse, A.J. and Duffield, G.E. (2000) The conservation and status of the Blue-throated macaw Ara glaucogularis. Bird Conservation International 10:255-275.

Duffield, G.E., McNulty, S. and Ebling, F.J.P. (1999) Anatomical and funcational characterization of a dopaminergic system in the suprachiasmatic nucleus of the neonatal Siberian hamster. Journal of Comparative Neurology 408:73-96.

von Gall, C., Duffield, G.E., Hastings, M.H., Kopp, M.D.A., Dehghani, F., Korf, H.-W., Stehle, J.H. (1998). CREB in the Mouse SCN: A Molecular Interface Coding the Phase-Adjusting Stimuli Light, Glutamate, PACAP, and Melatonin for Clockwork Access. Journal of Neuroscience 18: 10389-10397.

Duffield, G.E., Hastings, M.H. and Ebling, F.J.P. (1998). Investigation into the regulation of the circadian system by dopamine and melatonin in the Siberian hamster (Phodopus sungorus). Journal of Neuroendocrinology 10: 871-884.

Duffield, G.E. and Ebling, F.J.P. (1998). Maternal entrainment of developing circadian system in the Siberian hamster (Phodopus sungorus). Journal of Biological Rhythms 13:315-329.

Hastings, M.H., Duffield, G.E., Maywood, E.S., Smith, E.J.D. and Ebling, F.J.P. (1998). Entrainment of the circadian system of mammals by non-photic cues. Chronobiology International 15:425-445.

Hastings, M.H., Duffield, G.E., Ebling, F.J.P., Kidd, A., Maywood, E.S. and Schurov, I. (1997). Non-photic signalling in the suprachiasmatic nucleus. Biology of the Cell 89:495-503.

Duffield, G.E., Cronin, A.S. and Ebling, F.J.P. (1996). Expresssion of NMDAR1 splice variants in the developing suprachiasmatic nucleus (SCN) of the Siberian hamster (Phodoopus sungorus). Society for the Neuroscience Annual Meeting Abstract.

Duffield, G.E., Dickerson, J.M., Alexander, I.H.M. and Ebling, F.J.P. (1995). Ontogeny of a photic response in the suprachiasmatic nucleus in the Siberian hamster (Phodopus sungorus). European Journal of Neuroscience 7:1089-1096.

Duffield, G.E., Gibson, R.C., Gilhooly, P.M., Hesse, A.J., Inkley, C.R., Gilbert, F.S., and Barnard, C.J. (1993). Choice of flowers by foraging honeybees (Apis mellifera): possible morphological cues. Ecological Entomology 18:191-197.

Address for Correspondence

Tel. (603) 653 9933
Fax: (603) 653 9930
Email: Giles.Duffield@Dartmouth.EDU
g.duffield@imperial.ac.uk