Screening for Microtubule-Disrupting Antifungal Agents by Using a Mitotic-Arrest Mutant of Aspergillus nidulans and Novel Action of Phenylalanine Derivatives Accompanying Tubulin Loss

摘要: The microtubule, which is one of the major targets anthelmintics, anticancer drugs, and fungicides, composed mainly alpha- beta-tubulins. We focused on a unique characteristic an Aspergillus nidulans benA33 mutant to screen for microtubule-disrupting antifungal agents. This mutant, has beta-tubulin with mutation single amino acid, undergoes mitotic arrest due formation hyperstable microtubules at 37 degrees C. heat sensitivity remedied by some antimicrotubule found that agar plate assay was able distinguish three types microtubule inhibitors. growth recovery zones were formed around paper disks containing inhibitors, including four benzimidazoles, ansamitocin P-3, griseofulvin, rhizoxin, Nocodazole, thiabendazole, griseofulvin reversed promoted its hyphal growth. Ansamitocin P-3 rhizoxin showed growth-inhibitory zones. Benomyl carbendazim also but produced weaker than aforementioned drugs. Other such as colchicine, Colcemid, paclitaxel, podophyllotoxin, TN-16, vinblastine, vincristine, well cytoskeletal inhibitors tested, did not show activity. In our screening, we newly identified two mycotoxins, citrinin patulin, sesquiterpene dialdehydes, polygodial warburganal, phenylalanine derivatives, arphamenine A, L-2,5-dihydrophenylalanine (DHPA), N-tosyl-L-phenylalanine chloromethylketone, N-carbobenzoxy-L-phenylalanine chloromethyl ketone. wild-type strain A. nidulans, DHPA caused selective losses microtubules, determined fluorescence microscopy, both beta-tubulins, Western blot analysis. screening method involving useful, convenient, highly selective. derivatives tested are novel type agents, producing accompanying loss tubulins, different from well-known tubulin affecting assembly dimers into microtubules.