Elevated seawater pco2 differentially affects branchial acid-base transporters over the course of development in the cephalopod Sepia officinalis

Marian Y. Hu, Yung Che Tseng, Meike Stumpp, Magdalena A. Gutowska, Rainer Kiko, Magnus Lucassen, Frank Melzner

Research output: Contribution to journalArticle

62 Citations (Scopus)

Abstract

The specific transporters involved in maintenance of blood pH homeostasis in cephalopod molluscs have not been identified to date. Using in situ hybridization and immunohistochemical methods, we demonstrate that Na+/K+-ATPase (soNKA), a V-type H+-ATPase (soV-HA), and Na+/HCO-3 cotransporter (soNBC) are colocalized in NKA-rich cells in the gills of Sepia officinalis. mRNA expression patterns of these transporters and selected metabolic genes were examined in response to moderately elevated seawater PCO2 (0.16 and 0.35 kPa) over a time course of 6 wk in different ontogenetic stages. The applied CO2 concentrations are relevant for ocean acidification scenarios projected for the coming decades. We determined strong expression changes in late-stage embryos and hatchlings, with one to three log2-fold reductions in soNKA, soNBCe, socCAII, and COX. In contrast, no hypercapnia- induced changes in mRNA expression were observed in juveniles during both short- and long-term exposure. However, a transiently increased ion regulatory demand was evident during the initial acclimation reaction to elevated seawater PCO2. Gill Na+/K+-ATPase activity and protein concentration were increased by ∼15% during short (2-11 days) but not long-term (42-days) exposure. Our findings support the hypothesis that the energy budget of adult cephalopods is not significantly compromised during long-term exposure to moderate environmental hypercapnia. However, the downregulation of ion regulatory and metabolic genes in late-stage embryos, taken together with a significant reduction in somatic growth, indicates that cephalopod early life stages are challenged by elevated seawater PCO2.

Original languageEnglish
Pages (from-to)R1100-R1114
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume300
Issue number5
DOIs
Publication statusPublished - 2011 May 1

Keywords

  • Acid-base regulation
  • Embryonic development
  • Na/K-ATPase
  • Ocean acidification
  • SLC4 family

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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