Ultrastructural and protein analysis of surfactant in the Australian lungfish Neoceratodus forsteri: Evidence for conservation of composition for 300 million years

J.H. Power, I. R. Doyle, K. Davidson, T. E. Nicholas

    Research output: Contribution to journalArticle

    34 Citations (Scopus)

    Abstract

    The Australian lungfish Neoceratodus forsteri is the most primitive member of the lungfish family, with a surfactant lipid composition similar to the actinopterygiian fishes, which evolved 400 million years ago. We have analysed the proteins associated with surfactant isolated from lung lavage of this species, and used electron microscopy and immunohistochemistry to examine the surfactant structures and the subcellular localisation of these proteins. The epithelial lining of the gas-exchange region of the lungfish lung consists of one basic cell type, which has characteristics of both mammalian alveolar type I and type II cells and may be the common ancestor of both. It has long cytoplasmic plates containing microvilli, large osmiophilic bodies resembling mammalian lamellar bodies and a cytoplasm rich in metabolic organelles. Extracellular structures reminiscent of mammalian surfactant forms, but not including tubular myelin, were observed in the airspaces. Immunochemical analysis of the lungfish surfactant and lung tissue, using antibodies to human SP-A and SP-B, showed a similar staining pattern to human surfactant, indicating that SP-A- and SP-B-like proteins are present. Immunohistochemistry revealed that both SP-A and SP-B reactivity was present in the secretory cell osmiophilic bodies. In conclusion, our results suggest that, despite the great diversity in present day lung structures, a common cellular mechanism may have evolved to overcome fundamental problems associated with air-breathing.

    Original languageEnglish
    Pages (from-to)2543-2550
    Number of pages8
    JournalJournal of Experimental Biology
    Volume202
    Issue number18
    Publication statusPublished - 25 Aug 1999

    Keywords

    • Air-breathing
    • Electro n microscopy
    • Evolution
    • Immunohistochemistry
    • Lung
    • Neoceratodus forsteri
    • Surfactant

    Fingerprint Dive into the research topics of 'Ultrastructural and protein analysis of surfactant in the Australian lungfish Neoceratodus forsteri: Evidence for conservation of composition for 300 million years'. Together they form a unique fingerprint.

  • Cite this