Studies on the production of compounds and regulation of secondary metabolism by the cultures of isolated lichen mycobionts

地衣是共生生物体，由真菌（mycobiont）和光合作用伙伴（photobiont）组成。在某些情况下，培养的地衣分枝菌在植物应激条件下能够产生在地衣化状态下从未检测到的物质。指出地衣真菌培养物可能成为生物活性物质的新来源。在我们对培养地衣菌群的研究过程中，我们培养了在日本收集的地衣菌群，并研究了它们的代谢产物。从葡萄属的培养物中，色酮、苯醌和甾醇被分离，而苯并呋喃、氧杂蒽酮和脂肪族羧酸被分离自蜡蚧属的那些。从培养的真菌中，核壳菌属，获得了多种异香豆素衍生物。用C-标记的乙酸盐培养的Graphis、Lecanora和Pyrenula spp真菌，证实了萘并吡喃酮和氧杂蒽酮衍生物的纸盒骨架的生物起源<13>。从培养的真菌中分离的许多代谢产物在地衣化状态下从未被检测到，但在结构上与真菌毒素有关。这可能是假设，这些代谢物的代谢途径可以表达的生存的mycobiont在预地衣化的条件下，但抑制相关的地衣，因为它们的毒性的光生物。在这种情况下，一些代谢产物的影响的光合生物，Trebouxia erici的生长进行了研究，以证明，一些代谢产物抑制的光合生物的生长，但其他没有效果。还评价了一些分离的代谢产物对癌细胞系的抗增殖活性。

Lichens are symbiotic organisms comprised of a fungus, mycobiont, and a photosynthetic partner, photobiont. In some cases, cultures of lichen mycobionts have an ability under osmotically stressed conditions to produce substances which have never been detected in the lichenized state. It was pointed out that cultures of lichen mycobionts could be new sources of bioactive compounds. In the course of our studies on cultured lichen mycobionts, we cultivated mycobionts of the lichens collected in Japan and investigated their metabolites. From the cultures of Graphis spp., chromones, benzoquinones and a sterol were isolated, while benzofurans, xanthones and aliphatic carboxylic acids were isolated from those of Lecanora spp. From the cultured mycobionts, of Pyrenula spp., a variety of isocoumarin derivatives were obtained. The structures of thirteen new compounds were elucidated.The biogenetic origin of the carton skeleton in a naphthopyrone and xanthone derivatives was verified by feeding _<13>C-labeled acetate into the cultured mycobionts of Graphis, Lecanora and Pyrenula spp.A good many of diverse metabolites isolated from the cultured mycobionts have never been detected in the lichenized state but were structurally related to mycotoxins. It might be postulated that the metabolic pathways of these metabolites could be expressed for survival of the mycobiont in pre-lichenized condition, but suppressed in associated lichens because of their toxicity to photobiont. In this context, the effect of some metabolites on the growth of a photobiont, Trebouxia erici were studied to demonstrate that some metabolites inhibit the growth of the photobiont, but the other have no effect. The anti-proliferative activities of some isolated metabolites against a carcinoma cell line were also evaluated.