title: Rapid detection of lytic antimicrobial activity against yeast and filamentous fungi.
abstract: A rapid method for assessing the lytic activity of antimicrobial agents against yeast and fungi has been developed. The assay is based on the release of the intracellular enzyme, maltase (alpha-glucosidase). The released maltase activity was measured colorimetrically by the production of p-nitrophenol from p-nitrophenyl-alpha-D-glucopyranoside (PNPG). The lytic activity of different antimicrobial compounds was measured against yeast cells or germinating spores of filamentous fungi. Lytic anti-yeast activity could be detected within 20 min incubation at 30 degrees C against Saccharomyces cerevisiae, Candida albicans, and Cryptococcus neoformans. Lytic anti-fungal activity appeared after 2 h of incubation at 30 degrees C against germinating spores of Aspergillus niger and Botrytis cinerea. Whole cells of either yeast or fungi did not hydrolyze sufficient PNPG within 3 h at 30 degrees C to yield a detectable color change. Lytic activity of enzymes (e.g., Lyticase), antibiotics (e.g., Amphotericin B), and an antibiotic-producing strain of bacteria were detected using the assay. The anti-yeast assay has been adapted to a 96-well microtiter format. Both assays provided a rapid, sensitive, and reproducible detection of lytic anti-yeast and anti-fungal activity.
authors.affiliation: Fralin Biotechnology Center, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0346, USA.
authors.forename: Sally N
authors.initials: SN
authors.lastname: Jewell
authors.forename: Robert H
authors.initials: RH
authors.lastname: Waldo
authors.forename: Cody C
authors.initials: CC
authors.lastname: Cain
authors.forename: Joseph O
authors.initials: JO
authors.lastname: Falkinham
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology*; D005658:Fungi / Q000187:drug effects* / Q000201:enzymology / Q000502:physiology*; D006801:Humans; D006868:Hydrolysis; D008320:Maltose / Q000378:metabolism; D008826:Microbial Sensitivity Tests / Q000379:methods*; D009598:Nitrophenylgalactosides / Q000378:metabolism; D000520:alpha-Glucosidases / Q000378:metabolism*
chemical_list: D000935:Antifungal Agents; D009598:Nitrophenylgalactosides; C059200:4-nitrophenylgalactoside; D008320:Maltose; D000520:alpha-Glucosidases