Viability testing and characterization of germination of fungal spores by automatic image analysis

Abstract

Fungal spores are used in the laboratory for culture maintenance and at laboratory and other scales as inocula for fermentations. The spore swelling and germination processes constitute a major part of the lag phase, and the subsequent culture morphology and productivity can be greatly influenced by the initial concentration and condition of the spores. An image analysis method has been developed for assessing the viability and the germination characteristics of fungal spores in submerged cultures. Structural variations during germination, i.e., swelling, germ tube formation, and germ tube elongation, are measured in terms of distributions of spore volumes and of germ tube lengths and volumes. These measurements are fully automatic and give a very rapid assessment of spore viability. This image analysis method might be used as a tool in culture maintenance and for determining the quality of inocula for fungal fermentations.

On-line study of fungal morphology during submerged growth in a small flow-through cell

“…During spore germination, three phases can be recognized (Paul et al, 1993): Spore swelling, germ tube emergence, and germ tube elongation. Spore swelling may be subdivided into two phases, endogenous and exogenous swelling (Yanagita, 1957).…”

Hyphal growth and fragmentation of Penicillium chrysogenum in submerged cultures

“…However, in our analysis of experimental data we first quantify g(t) in (6) and it is then possible to use (12) to draw some qualitative conclusions concerning the average tip-extension rate in a culture of developing germ tubes. When spore germination ceases g(z,t) = 0 and the total number of hyphal elements becomes constant.…”

Image analysis of the morphology of filamentous micro-organisms

“…Paul et al (1993) developed a powerful method for this purpose and used it to study the germination of P. chrysogenum spores. In contrast to traditional methods for assessing the ability of spore preparations to germinate, i.e.…”

“…An attempt to model (mathematically) the swelling and germ tube formation failed (G. C. Paul, unpublished work), mainly because this lack of knowledge did not allow a rational choice of model structure. Nevertheless, Nielsen & Krabben (1995) used the data of Paul et al (1993) in a broader model of the penicillin fermentation. In any case, it is clear that image analysis would be a useful tool for investigating fungal spore germination and for improving our understanding of this important aspect of fungal growth.…”