Fatty acid and phospholipid syntheses are prerequisites for the cell cycle of Symbiodinium and their endosymbiosis within sea anemones

PLoS One. 2013 Aug 29;8(8):e72486. doi: 10.1371/journal.pone.0072486. eCollection 2013.

Abstract

Lipids are a source of metabolic energy, as well as essential components of cellular membranes. Although they have been shown to be key players in the regulation of cell proliferation in various eukaryotes, including microalgae, their role in the cell cycle of cnidarian-dinoflagellate (genus Symbiodinium) endosymbioses remains to be elucidated. The present study examined the effects of a lipid synthesis inhibitor, cerulenin, on the cell cycle of both cultured Symbiodinium (clade B) and those engaged in an endosymbiotic association with the sea anemone Aiptasia pulchella. In the former, cerulenin exposure was found to inhibit free fatty acid (FFA) synthesis, as it does in other organisms. Additionally, while it also significantly inhibited the synthesis of phosphatidylethanolamine (PE), it did not affect the production of sterol ester (SE) or phosphatidylcholine (PC). Interestingly, cerulenin also significantly retarded cell division by arresting the cell cycles at the G0/G1 phase. Cerulenin-treated Symbiodinium were found to be taken up by anemone hosts at a significantly depressed quantity in comparison with control Symbiodinium. Furthermore, the uptake of cerulenin-treated Symbiodinium in host tentacles occurred much more slowly than in untreated controls. These results indicate that FFA and PE may play critical roles in the recognition, proliferation, and ultimately the success of endosymbiosis with anemones.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Cycle / drug effects
  • Cell Cycle / physiology*
  • Cerulenin / pharmacology
  • Dinoflagellida / drug effects
  • Dinoflagellida / physiology*
  • Dose-Response Relationship, Drug
  • Fatty Acids / chemistry
  • Fatty Acids / metabolism*
  • Phospholipids / chemistry
  • Phospholipids / metabolism*
  • Sea Anemones / parasitology
  • Sea Anemones / physiology*
  • Starch / metabolism
  • Symbiosis*

Substances

  • Fatty Acids
  • Phospholipids
  • Cerulenin
  • Starch

Grant support

This study was supported by grants from the National Museum of Marine Biology and Aquarium (981001092 and 99200312) and National Science Council (NSC 101-2311-B-291-002-MY3). ABM was supported by a postdoctoral research fellowship from the Living Oceans Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.