A new cytotoxic 12-membered macrolactone from the endophytic fungus Exserohilum rostratum LPC-001.

A new oxacyclododecindione-type macrolactone, (13R,14S,15R)-13-hydroxy-14-deoxyoxacyclododecindione (1), has been obtained from the solid cultures of the fungus Exserohilum rostratum, a fungal strain endophytic in Gymnadenia conopsea. Its structure, including the absolute configuration, was extensively established by 1D and 2D NMR data, the modified Mosher method, and a combination of experimental and theoretically calculated electronic circular dichroism (ECD) spectra. Compound 1 showed weak selective cytotoxicity against the A549 lung cell line with an IC50 value of 9.2 µM.

In vitro rapid evolution of fungal immunomodulatory proteins by DNA family shuffling.

Fungal immunomodulatory proteins (FIPs) found in a wide variety of mushrooms hold significant therapeutic potential. Despite much research, the structural determinants for their immunomodulatory functions remain unknown. In this study, a DNA shuffling technique was used to create two shuffled FIP protein libraries: an intrageneric group containing products of shuffling between FIP-glu (FIP gene isolated from Ganoderma lucidum) and FIP-gsi (FIP gene isolated from Ganoderma sinense) genes and an intergeneric group containing the products of shuffling between FIP-glu, FIP-fve (FIP gene isolated from Flammulina velutipes), and FIP-vvo (FIP gene isolated from Volvariella volvacea) genes. The gene shuffling generated 426 and 412 recombinant clones, respectively. Using colony blot analysis, we selected clones that expressed relatively high levels of shuffled gene products recognized by specific polyclonal antibodies. We analyzed the DNA sequences of the selected shuffled genes, and testing of their protein products revealed that they maintained functional abilities to agglutinate blood cells and induce cytokine production by splenocytes from Kunming mice in vitro. Meanwhile, the relationships between protein structure and the hemagglutination activity and between the changed nucleotide sites and expression levels were explored by bioinformatic analysis. These combined analyses identified the nucleotide changes involved in regulating the expression levels and hemagglutination activities of the FIPs. Therefore, we were able to generate recombinant FIPs with improved biological activities and expression levels by using DNA shuffling, a powerful tool for the generation of novel therapeutic proteins and for their structural and functional studies.