title: The development of the pulmonary surfactant system in California sea lions.
abstract: Pulmonary surfactant has previously been shown to change during development, both in composition and function. Adult pinnipeds, unlike adult terrestrial mammals, have an altered lung physiology to cope with the high pressures associated with deep diving. Here, we investigated how surfactant composition and function develop in California sea lions (Zalophus californianus). Phosphatidylinositol was the major anionic phospholipid in the newborn, whereas phosphatidylglycerol was increased in the adult. This increase in phosphatidylglycerol occurred at the expense of phosphatidylinositol and phosphatidylserine. There was a shift from long chain and polyunsaturated phospholipid molecular species in the newborn to shorter chain and mono- and disaturated molecular species in the adult. Cholesterol and SP-B concentrations were also higher in the adult. Adult surfactant could reach a lower equilibrium surface tension, but newborn surfactant could reach a lower minimum surface tension. The composition and function of surfactant from newborn California sea lions suggest that this age group is similar to terrestrial newborn mammals, whereas the adult has a "diving mammal" surfactant that can aid the lung during deep dives. The onset of diving is probably a trigger for surfactant development in these animals.
authors.affiliation: Environmental Biology, School of Earth and Environmental Sciences, Darling Building, University of Adelaide, North Tce, Australia.
authors.forename: Natalie J
authors.initials: NJ
authors.lastname: Miller
authors.forename: Anthony D
authors.initials: AD
authors.lastname: Postle
authors.forename: Samuel
authors.initials: S
authors.lastname: Schürch
authors.forename: W
authors.initials: W
authors.lastname: Michael Schoel
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Daniels
authors.forename: Sandra
authors.initials: S
authors.lastname: Orgeig
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002784:Cholesterol / Q000032:analysis; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D008168:Lung / Q000378:metabolism; D008297:Male; D010743:Phospholipids / Q000032:analysis; D037662:Pulmonary Surfactant-Associated Protein A / Q000032:analysis; D037701:Pulmonary Surfactant-Associated Protein B / Q000032:analysis; D011663:Pulmonary Surfactants / Q000737:chemistry / Q000378:metabolism*; D046070:Sea Lions / Q000502:physiology*; D021241:Spectrometry, Mass, Electrospray Ionization; D013500:Surface Tension
chemical_list: D010743:Phospholipids; D037662:Pulmonary Surfactant-Associated Protein A; D037701:Pulmonary Surfactant-Associated Protein B; D011663:Pulmonary Surfactants; D002784:Cholesterol