Original Article A Cell Line (HEW) from Embryos of Haddock (Melanogrammus aeglefinius) and Its Capacity to Tolerate Environmental Extremes Steve P. Bryson, 1 Elizabeth M. Joyce, 1 D. John Martell, 2 Lucy E.J. Lee, 3 Shawn E. Holt, 4,5 Steve C. Kales, 1 Kazuhiro Fujiki, 1 Brian Dixon, 1 Niels C. Bols 1 1 Department of Biology, University of Waterloo, Waterloo, Ontario, Canada 2 Fisheries and Oceans Canada, St. Andrews NB, Canada 3 Department of Biology, Wilfrid Laurier University, Waterloo, Ontario, Canada 4 Departments of Pathology, Human Genetics, Pharmacology & Toxicology, Massey Cancer Center, Richmond, VA, USA 5 Mount Desert Biological Laboratory, Salisbury Cove, ME, USA Received: 5 November 2005 / Accepted: 8 May 2006/ Published online: 18 August 2006 Abstract Cell lines can be useful experimental tools for studying marine fish, which are often difficult to routinely obtain and maintain in the laboratory. As few cell lines are available from coldwater marine fish, cultures were initiated from late gastrula em- bryos of haddock (Melanogrammus aeglefinus) in Leibovitz’s L-15 with fetal bovine serum (FBS). From one culture, a cell line (HEW) emerged that has been grown for close to 100 population doublings, was heteroploid, and expressed telomerase activity, all of which suggest HEW is immortal. Growth occurred only if FBS was present and was optimal at 12 to 18-C. Usually most cells had an epithelial-like mor- phology, but under some conditions, cells drew up into round central bodies from which radiated cyto- plasmic extensions with multiple branches. These neural-like cells appeared within a few hours of cul- tures being placed at 28-C or being switch to a simple salt solution (SSS). At 28-C, cells died within 24 h. In SSS, HEW cells survived as a monolayer for at least 7 days. The sensitivity of HEW cells to mor- phological change and their capacity to withstand starvation should make them useful for investigat- ing cellular responses to environmental stresses. Keywords: fish cell line — haddock embryo — Melanogrammus aeglefinus — osmolality — stress — telomerase Introduction Cell lines from the early life stages of fish have a range of uses but very few have been prepared from marine species (Fryer and Lannan, 1994; Ganassin et al., 1999). The most common application is in detecting and studying viruses that can cause economic losses in aquaculture and in fisheries. However, another potential use is in studying the biology of early life stages at the cellular and molecular levels, which can be complex and difficult to explore for many species because of the restricted availability of these stages for laboratory experimentation. One exceptional fea- ture of early life stages in many marine species is the remarkable mortality rate, which can be as great as 99% (Heath, 1992). Although predation is a signifi- cant cause of death, several environmental stresses can contribute to the poor survival, including salin- ity, temperature, and starvation (Ferron and Leggett, 1994). Over the last three decades, the cellular response to environmental stress has been intensive- ly studied in a few groups of organisms (Ku ¨ ltz, 2005) but has received relatively less attention in fish. Cell lines from marine fish embryos and larvae would offer the possibility of studying cellular and bio- chemical responses to stresses known to impact on early life stage survival. Haddock, Melanogrammus aeglefinus, is being explored as an aquaculture species (LeFrancois et al., 2002; Aiken 2003), and a cell line could prove useful in detecting disease-causing viruses as well as in exploring the cellular physiology of early life stages. In this article, the development and charac- terization from haddock embryos of a cell line, HEW (Haddock Embryo Waterloo), is described and their capacity to survive environmental extremes is defined to provide an in vitro model for studying Correspondence to: Niels C. Bols; E-mail: ncbols@sciborg.uwaterloo.ca DOI: 10.1007/s10126-005-6163-1 & * Springer Science+Business Media, Inc. 2006 1