ORIGINAL PAPER Comparative analysis of crystallins and lipids from the lens of Antarctic toothfish and cow Andor J. Kiss • Arthur L. Devries • Rachael M. Morgan-Kiss Received: 9 January 2010 / Revised: 12 April 2010 / Accepted: 23 April 2010 Ó Springer-Verlag 2010 Abstract Animal model systems of senile cataract and lens crystallin stability are essential to understand the complex nature of lens transparency. Our aim in this study was to assess the long-lived Antarctic toothfish Dissostichus mawsoni (Norman) as a model system to understand long- term lens clarity in terms of solubility changes that occur to crystallins. We compared the toothfish with the mammalian model cow lens, dissecting each species’ lens into a cortex and nuclear region. In addition to crystallin distribution, we also assayed fatty acid (FA) composition by negative ion electrospray ionization mass spectrometry (ESI-MS). The majority of toothfish lens crystallins from cortex (90.4%) were soluble, whereas only a third (31.8%) from the nucleus was soluble. Crystallin solubility analysis by SDS-PAGE and immunoblots revealed that relative proportions of crystallins in both soluble and urea-soluble fractions were similar within each species examined and in agreement with previous reports for bovine lens. From our data, we found that both toothfish and cow crystallins follow patterns of insolubility that mirror each animals lens composition with more c crystallin aggregation seen in the toothfish lens nucleus than in cow. Toothfish lens lipids had a large amount of polyunsaturated fatty acids that were absent in cow resulting in an unsaturation index (I U ) four-fold higher than that of cow. We identified a novel FA with a molecular mass of 267 mass units in the lens epithelial layer of the toothfish that accounted for well over 50% of the FA abundance. The unidentified lipid in the toothfish lens epi- thelia corresponds to either an odd-chain (17 carbons) FA or a furanoid. We conclude that long-lived fishes are likely good animal models of lens crystallin solubility and may model post-translational modifications and solubility changes better than short-lived animal models. Keywords Lens Á Crystallins Á Antarctic toothfish Á Alpha crystallin Á Beta crystallin Á Gamma crystallin Á Lipid Á MALDI Á Albuminoid Á Fatty acid trophic marker (FATM) Introduction The Antarctic toothfish lens contains three types of lens crystallin proteins: a, b and c. Crystallins make up to 90% of the protein in the vertebrate lens (Davson 1990), and depending on the animals’ visual environment, can exist at very high concentrations between 250 mg mL -1 (terres- trial) and 1,000 mg mL -1 (aquatic) (Delaye and Tardieu 1983; Kroger et al. 1994). The predominant crystallins in mammalian lenses are the a and b crystallins (Bloemendal et al. 2004; Wistow 1993; Wistow et al. 2005), while in fish Communicated by H.V. Carey. A. J. Kiss Á A. L. Devries Department of Animal Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA A. J. Kiss (&) Laboratory for Ecophysiological Cryobiology, Department of Zoology, Miami University, Oxford, OH 45056, USA e-mail: kissaj@muohio.edu R. M. Morgan-Kiss Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA R. M. Morgan-Kiss Department of Microbiology, Miami University, Oxford, OH 45056, USA 123 J Comp Physiol B DOI 10.1007/s00360-010-0475-9