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Cytology and Histology

Acridine Orange as a Lysosome Marker in Fungal Spores. Charles L. Wilson, Research Plant Pathologist, Science and Education Administration, U.S. Department of Agriculture, and also Adjunct Professor, Department of Plant Pathology, Ohio Agricultural Research and Development Center, Wooster, OH 44691; Gene A. Jumper(2), and David L. Mason(3). (2)Graduate Research Associate, Department of Plant Pathology, The Ohio State University, Columbus, OH 43210; (3)Associate Professor, Biology Department, Wittenburg University, Springfield, OH 45507. Phytopathology 68:1564-1567. Accepted for publication 1 June 1978. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1978.. DOI: 10.1094/Phyto-68-1564.

Acridine orange fluoresces red-orange in the vacuoles of spores of Ceratocystis ulmi, Botrytis cinerea, and Cryptococcus neoformans placed under UV light. To compare animal and fungal lysosomes, mouse macrophages that had engulfed spores of C. neoformans were treated with acridine orange. Similar red-orange fluorescence under UV was observed in the animal macrophage and in the vacuoles of the fungal spore. Acid phosphatase (a marker for lysosomes) was concentrated primarily in the vacuole of the spores of B. cinerea. These results indicate that the vacuoles of C. ulmi, B. cinerea, and C. neoformans probably are lysosomes and that acridine orange can be used as a selective stain for these lysosomes in fungi just as it is used to detect lysosomes in animal cells.