Christopher Womersley

Research Interests

Physiological ecology/adaptive biochemistry; dehydration and freezing stress; biological control

My research focus is the study of the physiological/biochemical adaptations in response to extreme environmental stress. While various types of environmental stresses are studied, my research utilizes those animals that are able to tolerate dehydration stress as a model system. Essentially all animals are able to tolerate drying to some degree, but relatively few are able to survive extreme dehydration (removal of all body water), while still retaining structural and functional integrity. This is accomplished by entry into a dormant state of "suspended animation", called anhydrobiosis. The problem of anhydrobiotic survival, how this condition is attained and maintained, and how animals adapt to its effects has, until relatively recently been poorly understood, and comparative biochemical/biophysical studies on anhydrobiotic organisms are still in their infancy. My laboratory is one of the very few attempting such studies on multicellular organisms. I feel that, in terms of basic biology, these studies are of paramount importance in unraveling the mystery of anhydrobiotic survival and providing a deeper understanding of how water functions in fully hydrated systems. They may also provide new insights and directions to studies in applied fields.

Presently we are examining the role of carbohydrates in stabilizing a variety of biological systems during periods of low water activity. These include nematodes, tardigrades and rotifers. Such comparative studies have allowed us to question the accepted dogma that trehalose production is the specific metabolic adaptation necessary for stabilization and has led to findings that specific membrane components (i.e., phospholipids) can also be readily adapted to provide more stable membrane structures.

We are also actively researching the aging process itself - how this is controlled or even negated during cryptobiosis

Selected Publications

Womersley, C.Z, Wharton, D. and Higa, L.M. (1998). Survival Biology. In. Physiology and Biochemistry of Plant Parasitic and Free-living Nematodes. (Perry, R.N. and D.J. Wright, eds.) CABI Press, pp. 271-302.

Womersley, C.Z. (1993). Factors affecting physiological fitness and modes of survival employed by dauer larvae and their relationship to pathogenicity. In : Nematodes and the biological control of insect pests. (Bedding, R.A., Akhurst, R., and Kaya, H.K. eds.), CSIRO Press, pp. 79-88.

Womersley, C.Z. (1990). Dehydration survival and anhydrobiotic potential. In Entomopathogenic Nematodes in Biological Control. (R. Gaugler & H.K. Kaya, eds.), CRC Press, pp. 117-137.

Womersley, C. (1987). A reconsideration of diversity of adaptation in nematode anhydrobiotes in relation to their environments. In Vistas on Nematol. (A publication celebrating the 25th anniversary of the American Society of Nematologists); E.O. Painter Publ., pp. 165-173.

Refereed Articles

Guitierrez, L.M. and C.Z. Womersley (2000). Shadow responses and the possible role of dermal receptors in the Hawaiian black snail, Nerita picea (Gastropoda: Neritidae). The Veliger, 44 (1): 1-7.

Hill, K.T. and Womersley, C.Z. (1998). Fluorescent age-pigment accumulation and the use of multiple regression models for age estimation in two fish species. J. Exp. Mar. Biol. Ecol. (in press).

Womersley, C.Z., Higa, L.M. and Leonhardt, K.W. (1998). Entomopathogenic nematodes: Where they live, why they kill insects and ways to improve their biocontrol potential of insect pests in a protected Hawaiian Floriculture setting. Proceedings Fourth Multicommodity Cutflower Industry Conference, HITAHR (in press).

Womersley, C.Z. and Higa, L.M. (1998). Trehalose: its role in the anhydrobiotic survival of Ditylenchus myceliophagus. Nematologica 44, 1-22.

Leonhardt, K.W., Higa, L.M. and Womersley, C.Z. (1998). Biological Control of Insect Pests of Ornamentals Using Entomopathogenic Nematodes. Landsc. Flori. and Ornam. News No. 3, 10-11; Co-op. Extens. Ser., CTAHR/USDA.

Leonhardt, K.W., L.M. Higa, and C.Z. Womersley. (1995). The climate is right for biological control of insect pests of floral crops using entomopathogenic nematodes. Proceedings: Third Multicommodity Cutflower Industry Conference, HITAHR, pp. 68-71.

Higa, L.M. and Womersley, C.Z. (1993). New insights into the anhydrobiotic phenomenon: the effects of trehalose content and differential rates of evaporative water loss on the survival of Aphelenchus avenae. J. Exp. Zool., 267: 120-129.

Hill, K.T. and Womersley, C.Z. (1993). Interactive effects of some environmental and physiological parameters on fluorescent age pigment variability in brain and heart tissues of an aquatic poikilotherm. Env. Biol. Fish. (in press)

Hill, K.T. and Womersley, C. (1991). Critical aspects of current fluorescent age-pigment methodologies: modification for accurate analysis and age assessments in aquatic organisms. Mar. Biol., 109: 1-11.

Womersley, C. and Ching, C. (1989). Natural dehydration regimes as a prerequisite for the successful induction of anhydrobiosis in the nematode Rotylenchulus reniformis. J. Exp. Biol., 143: 359-372.