title: Visualization analysis of the vacuole-targeting fungicidal activity of amphotericin B against the parent strain and an ergosterol-less mutant of Saccharomyces cerevisiae.
abstract: Here, we sought to investigate the vacuole-targeting fungicidal activity of amphotericin B (AmB) in the parent strain and AmB-resistant mutant of Saccharomyces cerevisiae and elucidate the mechanisms involved in this process. Our data demonstrated that the vacuole-targeting fungicidal activity of AmB was markedly enhanced by N-methyl-N″-dodecylguanidine (MC12), a synthetic analogue of the alkyl side chain in niphimycin, as represented by the synergy in their antifungal activities against parent cells of S. cerevisiae. Indifference was observed only with Δerg3 cells, indicating that the replacement of ergosterol with episterol facilitated their resistance to the combined lethal actions of AmB and MC12. Dansyl-labelled amphotericin B (AmB-Ds) was concentrated into normal rounded vacuoles when parent cells were treated with AmB-Ds alone, even at a non-lethal concentration. The additional supplementation of MC12 resulted in a marked loss of cell viability and vacuole disruption, as judged by the fluorescence from AmB-Ds scattered throughout the cytoplasm. In Δerg3 cells, AmB-Ds was scarcely detected in the cytoplasm, even with the addition of MC12, reflecting its failure to normally incorporate across the plasma membrane into the vacuole. Thus, this study supported the hypothesis that ergosterol is involved in the mobilization of AmB into the vacuolar membrane so that AmB-dependent vacuole disruption can be fully enhanced by cotreatment with MC12.
authors.affiliation: Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.
authors.forename: Chang-Kyung
authors.initials: CK
authors.lastname: Kang
authors.affiliation: Department of Chemistry and Chemical Biology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Yamada
authors.affiliation: Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.
authors.forename: Yoshinosuke
authors.initials: Y
authors.lastname: Usuki
authors.affiliation: Research Center for Urban Health and Sports, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.|Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Ogita
authors.affiliation: Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.
authors.forename: Ken-Ichi
authors.initials: KI
authors.lastname: Fujita
authors.affiliation: Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.
authors.forename: Toshio
authors.initials: T
authors.lastname: Tanaka
mesh_terms: D000666:Amphotericin B / Q000378:metabolism* / Q000494:pharmacology; D000935:Antifungal Agents / Q000378:metabolism* / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D025141:Drug Resistance, Fungal; D004875:Ergosterol / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D014617:Vacuoles / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000935:Antifungal Agents; D000666:Amphotericin B; D004875:Ergosterol