The biosynthesis of the diterpene 8␣-acetoxy-13␣-hydroxy-5-oxo-13-epi-neoverrucosane in the arctic liverwort Fossombronia alaskana was studied by incorporation experiments using [1-13 C]-and [U-13 C 6 ]glucose as precursors. The 13 C-labeling patterns of acetyl-CoA, pyruvate, and phosphoenolpyruvate in intermediary metabolism were reconstructed from the 13 C NMR data of biosynthetic amino acids (leucine, alanine, phenylalanine) and were used to predict hypothetical labeling patterns for isopentenyl pyrophosphate formed via the mevalonate pathway and the deoxyxylulose pathway. The labeling patterns observed for the neoverrucosane diterpene were consistent with the intermediate formation of geranyllinaloyl pyrophosphate assembled from dimethylallyl pyrophosphate and three molecules of isopentenyl pyrophosphate generated predominantly or entirely via 1-deoxyxylulose 5-phosphate. The experimental data can be integrated into a detailed biosynthetic scheme involving a 1,5-hydride shift. The postulated involvement of the 1,5-hydride shift was confirmed by an incorporation experiment with [6,6-2 H 2 ]glucose.Verrucosanes are a family of tetracyclic diterpenes initially observed in the liverworts Mylia anomala (1) and Mylia verrucosa (2-6). More recently, verrucosane type terpenes have also been found in other liverworts (7)(8)(9)(10)(11)(12)(13)(14), in marine sponges (15)(16)(17) and in the eubacterium Chloroflexus aurantiacus (18). The structures of 5␤-hydroxy-13-epi-neoverrucosane from the liverwort Plagiochila stephensoniana (9) and of 5-oxo-13-epi-neoverrucosane from Fossombronia alaskana (7) have been determined by x-ray structure analysis. The major diterpene from axenic cultures of F. alaskana was found to be 8␣-acetoxy-13␣-hydroxy-5-oxo-13-epi-neoverrucosane (1, Fig.

The polymer induced ali@ment (PIA) tcchniqne is presented as B new technique to grow single-crystalline films of linear telomers. Combining the PIA technique with special high-resolution Brillouin techniques. it is possible 10 determine the coefficienls of Ihe elastic stiffness tenwr of the crystalline state of linear lelomen. especially in their rotator phases. As model systems we have chosen the perfluoroalkane Ca~Fhz and the linear n-alkane C17H36. A comparison of elaslic data obtained from classically and PIA grown samples proves their equivdenee as well as their complemenlarity. Precursors of critical melting discovered xn the rataiotOr phase of C17Hy axe discussed in terms of the anomalous temperature dependence of cefiain elastic tensor coefficients and of related n-telomers.

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