Structure, Function, and Motility of Vacuoles in Filamentous Fungi

• Published in: Fungal genetics and biology Vol. 24; no. 1-2; pp. 86 - 100
• Main Authors: Cole, Louise, Orlovich, David A., Ashford, Anne E.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.06.1998
• Subjects: endocytosis; fluorescent probes; FM4-64; freeze substitution; fungal transport; MDY-64; motile tubular vacuole; Oregon green 488; phosphorus storage; Pisolithus tinctorius; motile tubular vacuole; MDY-64; FM4-64; endocytosis; fungal transport; phosphorus storage; freeze substitution; fluorescent probes; Oregon green 488; Pisolithus tinctorius
• ISSN: 1087-1845; 1096-0937
• DOI: 10.1006/fgbi.1998.1051

Current information on the structure and function of motile tubular vacuoles inPisolithus tinctoriusand other fungi is reviewed. The use of fluorochromes to label the vacuole lumen is evaluated and observations on the structure and motility of vacuoles inP. tinctoriusare differentiated from possible artifacts. The styryl dyes FM4-64 and MDY-64, used in yeast to demonstrate endocytosis, show little or no labeling of internal membranes in undamagedP. tinctoriuscells. This agrees with our data showing that other probes for endocytosis such as Lucifer yellow CH are not taken up by hyphal tip cells. Overall, the observations do not support endocytosis in hyphal tips. It has been suggested that tubular vacuole systems carry out longitudinal transport, and evidence in favor of this hypothesis is evaluated. New data are presented to show that many of the large vacuoles in subapical cells are attached to the plasma membrane and are relatively immobile, while video sequences show movement of fluorochrome in pulses along a series of several large vacuoles, all interconnected via tubules. Tubular vacuoles from thick sections of hyphae processed under anhydrous conditions are shown by X-ray microanalysis to contain relatively high levels of P and K, as seen previously in the larger vacuoles. These results provide further evidence for a role of the tubular vacuoles in longitudinal transport of P.