GROWTH AND MITOGENIC EFFECTS OF ARYLPHORIN IN VIVO AND IN VITRO

Authors: HAKIM, RAZIEL - HOWARD UNIV.; Blackburn, Michael - Mike; CORTI, P. - UNIVE. OF MILIAN; Gelman, Dale; Goodman, Cynthia; ELSIN, KIM - FREE UNIV. OF BRUSSELS; Loeb, Marcia; Lynn, Dwight; SMAGGHE, GUY - GHENT UNIVERSITY

Submitted to: Archives of Insect Biochemistry and Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/17/2007
Publication Date: 2/20/2007
Citation: Hakim, R.S., Blackburn, M.B., Corti, P., Gelman, D.B., Goodman, C.L., Elsin, K., Loeb, M.J., Lynn, D.E., Smagghe, G. 2007. Growth and mitogenic effects of arylphorin in vivo and in vitro. Archives of Insect Biochemistry and Physiology. 64:63-73.

Interpretive Summary: The tobacco budworm, cotton leafworm, cabbage looper, Colorado potato beetle and sweet potato whitefly cause billions of dollars in crop losses each year. Knowing more about how the insect gut grows and repairs itself could lead to improvements in the efficacy of certain insect control agents that target the gut, such as bacteria and viruses. We have recently shown that a protein from the tobacco hornworm, arylphorin, causes growth of primitive cells (stem cells) that later develop into mature gut cells in the tobacco budworm. In this report we show that arylphorin also stimulates the gut stem cells of immature tobacco hornworm and cotton leafworm to grow, as well as cells derived from fat cells of the gypsy moth. We found that arylphorin has an effect on some insects when it is fed to them; the protein caused immature tobacco hornworm, cotton leafworm, cabbage looper, and Colorado potato beetle to gain significantly more weight than insects fed an artificial diet alone. Arylphorin had no effect on sweet potato whiteflies when fed to immature stages. This information will be used by scientists trying to develop ways of interfering with normal growth and healing of the insect gut.

Technical Abstract: The storage protein arylphorin from the tobacco hornworm, Manduca sexta, has recently been shown to stimulate proliferation of midgut stem cells in the tobacco budworm, Heliothis virescens. In this study we report that midgut stem cells of tobacco hornworm and the cotton leafworm, Spodptera littoralis, are also stimulated by arylphorin. Arylphorin did not have any effects on the growth of a number of continuous insect cell lines, except for a cell line derived from fat body of the gypsy moth, Lymantria dispar, which grew significantly better in the presence of arylphorin. Tobacco hornworm, cotton leafworm, cabbage looper (Trichplusia ni), and Colorado potato beetle (Leptinotarsa decemlineata) larvae fed arylphorin in artificial diets grew significantly larger than larvae fed artificial diet alone, while sweet potato whitefly (Bemisia tabaci) nymphs fed arylphorin in an artificial diet were not affected by the protein additive.