Viability of yeast form cells of Paracoccidioides brasiliensis after sonication

• Published in: Medical mycology (Oxford) Vol. 42; no. 1; pp. 43 - 49
• Main Authors: Fernanda Reis Gavazzoni Dias, Maria, Mesquita, Jacilene, Rodrigues, Noêmia, Lima Filgueira, Absalom, De Souza, Wanderley
• Format: Journal Article
• Language: English
• Published: UK Informa UK Ltd 01-02-2004
• Subjects: Culture Media; Janus; Microbiological Techniques; Microscopy, Electron; Paracoccidioides - growth & development; Paracoccidioides - ultrastructure; Paracoccidioides brasiliensis; Sonication; Staining and Labeling - methods; paracoccidioidomycosis; electron microscopy; vital dyes; sonication method; Paracoccidioides brasiliensis
• ISSN: 1369-3786; 1460-2709
• DOI: 10.1080/13693780310001610074

To perform in-vitro studies with Paracoccidioides brasiliensis yeast cells it is necessary to avoid the presence of clumps of cells while maintaining their integrity. Because of the multiple budding type of growth, the bud cells are always attached to the mother cell and the yeast cells keep growing, resulting in the formation of large clumps. In order to obtain free cells, the cultures are usually sonicated. The present study shows that sonication induces lesions in a significant number of cells, as evaluated by labelling of the cells with acridine orange and Janus green vital dyes. In some cases labelling was initially observed in only one cell of the clump; however, the other cells also became labelled after a few minutes. These observations were confirmed by scanning and transmission electron microscopy of treated cells. Colony forming units (c.f.u.) on BHI plates also confirmed the decrease in cell viability following sonication.