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Membrane homeoviscous adaptation in the piezo-hyperthermophilic archaeon Thermococcus barophilus.

Cario A, Grossi V, Schaeffer P, Oger PM - Front Microbiol (2015)

Bottom Line: Noticeably, pressure and temperature fluctuations also impact the level of unsaturation of apolar lipids having an irregular polyisoprenoid carbon skeleton (unsaturated lycopane derivatives), suggesting a structural role for these neutral lipids in the membrane of T. barophilus.Whether these apolar lipids insert in the membrane or not remains to be addressed.However, our results raise questions about the structure of the membrane in this archaeon and other Archaea harboring a mixture of di- and tetraether lipids.

View Article: PubMed Central - PubMed

Affiliation: CNRS, Laboratoire de Géologie de Lyon, Ecole Normale Supérieure de Lyon, UMR 5276, Université Claude Bernard Lyon 1 Lyon, France.

ABSTRACT
The archaeon Thermococcus barophilus, one of the most extreme members of hyperthermophilic piezophiles known thus far, is able to grow at temperatures up to 103°C and pressures up to 80 MPa. We analyzed the membrane lipids of T. barophilus by high performance liquid chromatography-mass spectrometry as a function of pressure and temperature. In contrast to previous reports, we show that under optimal growth conditions (40 MPa, 85°C) the membrane spanning tetraether lipid GDGT-0 (sometimes called caldarchaeol) is a major membrane lipid of T. barophilus together with archaeol. Increasing pressure and decreasing temperature lead to an increase of the proportion of archaeol. Reversely, a higher proportion of GDGT-0 is observed under low pressure and high temperature conditions. Noticeably, pressure and temperature fluctuations also impact the level of unsaturation of apolar lipids having an irregular polyisoprenoid carbon skeleton (unsaturated lycopane derivatives), suggesting a structural role for these neutral lipids in the membrane of T. barophilus. Whether these apolar lipids insert in the membrane or not remains to be addressed. However, our results raise questions about the structure of the membrane in this archaeon and other Archaea harboring a mixture of di- and tetraether lipids.

No MeSH data available.


Related in: MedlinePlus

Variations in the mean unsaturation level of lycopane derivatives in T. barophilus. Partial GC–MS chromatograms (TIC) of the isolated apolar lipids of T. barophilus as a function of pressure (P) and temperature (T). 40:X indicates a compound with a lycopane C40 carbon skeleton and X double bond(s). The major peak observed under optimal growth conditions is highlighted by a light gray background.
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Figure 4: Variations in the mean unsaturation level of lycopane derivatives in T. barophilus. Partial GC–MS chromatograms (TIC) of the isolated apolar lipids of T. barophilus as a function of pressure (P) and temperature (T). 40:X indicates a compound with a lycopane C40 carbon skeleton and X double bond(s). The major peak observed under optimal growth conditions is highlighted by a light gray background.

Mentions: In addition to variations in the relative proportions of the two major core lipids, the degree of unsaturation of lycopane derivatives synthesized by T. barophilus was also observed to vary according to conditions of pressure or temperature (Table 1; Figure 4). The average number of double bonds in unsaturated lycopane derivatives increased from 2.9 to 3.7 when the growth pressure was increased from 40 to 70 MPa, and decreased to 2.5 at atmospheric pressure. The effect of temperature mirrored that of pressure, with the average number of unsaturation in lycopane derivatives increasing to 3.8 at low temperature (80°C), and decreasing to 2.2 at high temperature (90°C; Table 1; Figure 4).


Membrane homeoviscous adaptation in the piezo-hyperthermophilic archaeon Thermococcus barophilus.

Cario A, Grossi V, Schaeffer P, Oger PM - Front Microbiol (2015)

Variations in the mean unsaturation level of lycopane derivatives in T. barophilus. Partial GC–MS chromatograms (TIC) of the isolated apolar lipids of T. barophilus as a function of pressure (P) and temperature (T). 40:X indicates a compound with a lycopane C40 carbon skeleton and X double bond(s). The major peak observed under optimal growth conditions is highlighted by a light gray background.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4612709&req=5

Figure 4: Variations in the mean unsaturation level of lycopane derivatives in T. barophilus. Partial GC–MS chromatograms (TIC) of the isolated apolar lipids of T. barophilus as a function of pressure (P) and temperature (T). 40:X indicates a compound with a lycopane C40 carbon skeleton and X double bond(s). The major peak observed under optimal growth conditions is highlighted by a light gray background.
Mentions: In addition to variations in the relative proportions of the two major core lipids, the degree of unsaturation of lycopane derivatives synthesized by T. barophilus was also observed to vary according to conditions of pressure or temperature (Table 1; Figure 4). The average number of double bonds in unsaturated lycopane derivatives increased from 2.9 to 3.7 when the growth pressure was increased from 40 to 70 MPa, and decreased to 2.5 at atmospheric pressure. The effect of temperature mirrored that of pressure, with the average number of unsaturation in lycopane derivatives increasing to 3.8 at low temperature (80°C), and decreasing to 2.2 at high temperature (90°C; Table 1; Figure 4).

Bottom Line: Noticeably, pressure and temperature fluctuations also impact the level of unsaturation of apolar lipids having an irregular polyisoprenoid carbon skeleton (unsaturated lycopane derivatives), suggesting a structural role for these neutral lipids in the membrane of T. barophilus.Whether these apolar lipids insert in the membrane or not remains to be addressed.However, our results raise questions about the structure of the membrane in this archaeon and other Archaea harboring a mixture of di- and tetraether lipids.

View Article: PubMed Central - PubMed

Affiliation: CNRS, Laboratoire de Géologie de Lyon, Ecole Normale Supérieure de Lyon, UMR 5276, Université Claude Bernard Lyon 1 Lyon, France.

ABSTRACT
The archaeon Thermococcus barophilus, one of the most extreme members of hyperthermophilic piezophiles known thus far, is able to grow at temperatures up to 103°C and pressures up to 80 MPa. We analyzed the membrane lipids of T. barophilus by high performance liquid chromatography-mass spectrometry as a function of pressure and temperature. In contrast to previous reports, we show that under optimal growth conditions (40 MPa, 85°C) the membrane spanning tetraether lipid GDGT-0 (sometimes called caldarchaeol) is a major membrane lipid of T. barophilus together with archaeol. Increasing pressure and decreasing temperature lead to an increase of the proportion of archaeol. Reversely, a higher proportion of GDGT-0 is observed under low pressure and high temperature conditions. Noticeably, pressure and temperature fluctuations also impact the level of unsaturation of apolar lipids having an irregular polyisoprenoid carbon skeleton (unsaturated lycopane derivatives), suggesting a structural role for these neutral lipids in the membrane of T. barophilus. Whether these apolar lipids insert in the membrane or not remains to be addressed. However, our results raise questions about the structure of the membrane in this archaeon and other Archaea harboring a mixture of di- and tetraether lipids.

No MeSH data available.


Related in: MedlinePlus