1. Academic Validation
  2. Isolation and characterization of 1-palmitoyl-2-linoleoyl-sn-glycerol as a hormogonium-inducing factor (HIF) from the coralloid roots of Cycas revoluta (Cycadaceae)

Isolation and characterization of 1-palmitoyl-2-linoleoyl-sn-glycerol as a hormogonium-inducing factor (HIF) from the coralloid roots of Cycas revoluta (Cycadaceae)

  • Sci Rep. 2019 Mar 18;9(1):4751. doi: 10.1038/s41598-019-39647-8.
Yasuyuki Hashidoko 1 Hiroaki Nishizuka 2 Manato Tanaka 2 Kanako Murata 2 Yuta Murai 3 Makoto Hashimoto 2
Affiliations

Affiliations

  • 1 Division of Applied Bioscience, Research Faculty of Agriculture, Hokkaido University, Kita 9 Nishi 9, Kita-ku, Sapporo, 060-8589, Japan. yasu-h@abs.agr.hokudai.ac.jp.
  • 2 Division of Applied Bioscience, Research Faculty of Agriculture, Hokkaido University, Kita 9 Nishi 9, Kita-ku, Sapporo, 060-8589, Japan.
  • 3 Division of Life Science, Graduate School of Life Science, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo, 060-0810, Japan.
Abstract

Coralloid roots are specialized tissues of cycads (Cycas revoluta) that are involved in symbioses with nitrogen-fixing Nostoc cyanobacteria. We found that a crude methanolic extract of coralloid roots induced differentiation of the filamentous cell aggregates of Nostoc species into motile hormogonia. Hence, the hormogonium-inducing factor (HIF) was chased using bioassay-based isolation, and the active principle was characterized as a mixture of diacylglycerols (DAGs), mainly composed of 1-palmitoyl-2-linoleoyl-sn-glycerol (1), 1-palmitoyl-2-oleoyl-sn-glycerol (2), 1-stearoyl-2-linolenoyl-sn-glycerol (3), and 1-stearoyl-2-linoleoyl-sn-glycerol (4). Enantioselectively synthesised compound 1 showed a clear HIF activity at 1 nmol (0.6 µg) disc-1 for the filamentous cells, whereas synthesised 2-linoleoyl-3-palmitoyl-sn-glycerol (1') and 1-palmitoyl-2-linoleoyl-rac-glycerol (1/1') were less active than 1. Conversely, synthesised 1-linoleoyl-2-palmitoyl-rac-glycerol (8/8') which is an acyl positional isomer of compound 1 was inactive. In addition, neither 1-monoacylglycerols nor Phospholipids structurally related to 1 showed HIF-like activities. As DAGs are protein kinase C (PKC) activators, 12-O-tetradecanoylphorbol-13-acetate (12), urushiol C15:3-Δ10,13,16 (13), and a skin irritant anacardic acid C15:1-Δ8 (14) were also examined for HIF-like activities toward the Nostoc cells. Neither 12 nor 13 showed HIF-like activities, whereas 14 showed an HIF-like activity at 1 nmol/disc. These findings appear to indicate that some DAGs act as hormogonium-inducing signal molecules for filamentous Nostoc cyanobacteria.

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