Accumulation of cyclitols functioning as compatible solutes in the haptophyte alga Pavlova sp.

Abstract

Using nuclear magnetic resonance spectroscopy, we identified and characterized accumulated compatible solutes in cells of the haptophyte alga Pavlova sp. strain CCMP504. The predominant organic solutes were D-1,4/2,5-cyclohexanetetrol (CHT), 1,3,5/2,4-cyclohexanepentol (CHP) and scyllo-inositol. We then profiled the intracellular organic solutes present in Pavlova sp. grown in medium with salinity ranging from 23 practical salinity units (PSU) (hyposaline) to 35 PSU (optimum salinity for growth), to 47 PSU (hypersaline). The results of these analyses reveal progressive accumulation of CHT and CHP in response to increasing growth medium salinity. We also observed altered accumulation of CHT and CHP in samples subjected to salinity shock. To further characterize the CHT and CHP biosynthesis in Pavlova sp., we carried out stable isotope feeding experiments. Specific labeling of CHT and CHP with D-13 C-glucose suggested that D-glucose is a biosynthetic precursor of these cyclitols. The salinity-induced accumulation of CHT and CHP suggests that these cyclitols act as compatible solutes. Our results therefore provide new evidence supporting classification of CHP as a compatible solute.

Metabolomics-derived marker metabolites to characterize Phaeocystis pouchetii physiology in natural plankton communities

“…phosphor storage 51 . The rare stereoisomer scyllo-inositol was reported for the haptophyte Pavlova, however, with unknown function 52 . Induced lipid metabolism during early and late stationary growth is further reflected by elevated levels of glyceraldehyde and methylated C18-polyunsaturated fatty acids (PUFAs).…”

NITZSCHIA OVALIS(BACILLARIOPHYCEAE) MONO LAKE STRAIN ACCUMULATES 1,4/2,5 CYCLOHEXANETETROL IN RESPONSE TO INCREASED SALINITY1

“…The presence of this cyclitol would be difficult to overlook due to the significantly high concentration reported in algae, such as Porphyridium, where this cyclitol is the second most important photoassimilate after floridoside in red algae, while in P. lutheri it can account for 7% of dry weight and in Pavlova sp. between 26% and 27% of total organic solute (Laycock and Craigie 1970, Reed 1990, Kobayashi et al. 2007).…”

“…In our experiments with N. ovalis extracts, we did not detect myo-inositol in the GC-MS analysis (with a detection limit of 0.14 fmol AE cell )1 ). Likewise, in the haptophyte Pavlova sp., myo-inositol was determined not to be a precursor of 1,4/2,5 cyclohexanetetrol, and only glucose has been identified as a precursor of this cyclitol (Kobayashi et al 2007). It is expected that the cyclitol biochemical pathway may be closely related to the Calvin cycle since it is light dependent in P. lutheri (Craigie 1969).…”

“…The osmoprotectant 1,4 ⁄ 2,5 cyclohexanetetrol has been identified by NMR spectrum in the Prymnesiophyceae P. lutheri and Pavlova sp. (Ramanathan et al 1966, Kobayashi et al 2007. A compound crystallized from Porphyridium sp.…”

“…This polyol has been isolated and identified by NMR from Pavlova lutheri (as Monochrysis lutheri Green 1975) and Pavlova sp. (Ramanathan et al 1966, Kobayashi et al 2007). But there is no full mass spectrogram of this diasteroisomer or its acetylated compound.…”