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

Wang LH, Lee HH, Fang LS, Mayfield AB, Chen CS - PLoS ONE (2013)

Bottom Line: 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).Cerulenin-treated Symbiodinium were found to be taken up by anemone hosts at a significantly depressed quantity in comparison with control Symbiodinium.

View Article: PubMed Central - PubMed

Affiliation: National Museum of Marine Biology and Aquarium, Checheng, Pingtung, Taiwan.

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.

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Sampling time for Symbiodinium sp. during a light–dark photoperiod.
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pone-0072486-g001: Sampling time for Symbiodinium sp. during a light–dark photoperiod.

Mentions: The cell cycle progression was determined by flow cytometry according to a published procedure [16]. Briefly, three cultures maintained at the exponential growth stage (5×104 cells ml−1) were sampled for analyses. 106 cells were collected at the times indicated in Fig. 1. Cells were harvested by centrifugation at 68×g for 5 min and fixed in ice-cold 70% ethanol for 1 h at 18 μmol m−2s−1 to extract the chlorophyll. Cells were then incubated in phosphate-buffered saline (PBS) containing Triton-X 100 (0.1%, Pharmacia Biotech, Sweden), RNase (10 μg ml−1, Sigma, USA), and propidium iodide (PI; 30 μg ml−1, Invitrogen, USA) at 4°C overnight in the dark. The DNA content per cell calculated from the DNA–PI complex fluorescence under 488/610 nm (Excitation/Emission) with an EPICS ALTRATM flow cytometer (Beckman Coulter, Inc., USA). Histograms of relative DNA content were analyzed using MultiCycle AV for Windows V5.0 (Phoenix Flow Systems, CA) in order to quantify the percentage of cells at each stage: G1, S, and G2/M.


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

Wang LH, Lee HH, Fang LS, Mayfield AB, Chen CS - PLoS ONE (2013)

Sampling time for Symbiodinium sp. during a light–dark photoperiod.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3756969&req=5

pone-0072486-g001: Sampling time for Symbiodinium sp. during a light–dark photoperiod.
Mentions: The cell cycle progression was determined by flow cytometry according to a published procedure [16]. Briefly, three cultures maintained at the exponential growth stage (5×104 cells ml−1) were sampled for analyses. 106 cells were collected at the times indicated in Fig. 1. Cells were harvested by centrifugation at 68×g for 5 min and fixed in ice-cold 70% ethanol for 1 h at 18 μmol m−2s−1 to extract the chlorophyll. Cells were then incubated in phosphate-buffered saline (PBS) containing Triton-X 100 (0.1%, Pharmacia Biotech, Sweden), RNase (10 μg ml−1, Sigma, USA), and propidium iodide (PI; 30 μg ml−1, Invitrogen, USA) at 4°C overnight in the dark. The DNA content per cell calculated from the DNA–PI complex fluorescence under 488/610 nm (Excitation/Emission) with an EPICS ALTRATM flow cytometer (Beckman Coulter, Inc., USA). Histograms of relative DNA content were analyzed using MultiCycle AV for Windows V5.0 (Phoenix Flow Systems, CA) in order to quantify the percentage of cells at each stage: G1, S, and G2/M.

Bottom Line: 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).Cerulenin-treated Symbiodinium were found to be taken up by anemone hosts at a significantly depressed quantity in comparison with control Symbiodinium.

View Article: PubMed Central - PubMed

Affiliation: National Museum of Marine Biology and Aquarium, Checheng, Pingtung, Taiwan.

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.

Show MeSH
Related in: MedlinePlus