SummaryFructans are the main storage carbohydrates of temperate grasses, sustaining regrowth immediately after defoliation, as well as contributing to the nutritive value of feed. Fructan metabolism is based on the substrate sucrose and involves fructosyltransferases (FTs) for biosynthesis and fructan exohydrolases (FEHs) for degradation. Sucrose is also utilized by invertases (INVs), which hydrolyse it into its constituent monosaccharides for use in metabolism. The isolation, molecular characterization, functional analysis, and phylogenetic relationships of genes encoding FTs, FEHs, and INVs from temperate grasses are reviewed, with an emphasis on perennial ryegrass ( Lolium perenne L.). The roles these enzymes play in fructan accumulation and remobilization, and future biotechnological applications in molecular plant breeding are discussed.

Using HPLC/microtiter-plate-based generation of activity profiles the extract of a marine alga-derived fungus, identified as Gliocladium sp., was shown to contain the known strongly cytotoxic metabolite 4-keto-clonostachydiol (1) and also clonostachydiol (2) as well as gliotide (3), a new cyclodepsipeptide containing several D-amino acids. The absolute configuration of 1 was elucidated by reduction to 2, and two further oxidized derivatives of clonostachydiol (5, 6) were prepared and evaluated for biological activity.

A new tetramic acid derivative, paecilosetin (1), along with a recently characterized N-hydroxypyridone, farinosone B (2), was isolated from the fungus Paecilomyces farinosus. Each compound showed activity against the P388 cell line with IC50 values of 3.1 and 1.1 microg/mL, respectively. Paecilosetin was also active against the microorganisms Bacillus subtilis, Trichophyton mentagrophytes, and Cladosporium resinae.

The entomopathogenic fungus Hirsutella sp., isolated from an infected spider, was found to produce the new cyclotetrapeptide hirsutide (1), cyclo-(L-NMe-Phe-L-Phe-L-NMe-Phe-L-Val), along with the known cytochalasin Q (2), using a cytotoxicity-guided isolation procedure. The structure of 1 was elucidated using one- and two-dimensional NMR experiments, mass spectrometry, and Marfey's method for analyzing the configuration of the amino acids.