The saprophytic growth of Keratinophilic fungi on keratin

Abstract

The growth of 9 species of keratinophilic fungi belonging to the genera Keratinomyces, Microsporum, Trichophyton and Epidermophyton was studied in vitro on hair, hedgehog spine, nail and callus. On hair digestion is carried out primarily by means of flat fronds of eroding mycelium which first life the cuticular scales and then erode the cortex. The well-known perforating organs arise from these fronds and in their turn may prouce further eroding mycelium which grows longitudinally through the cortex of the hair. The mechanism of penetration by perforating organs is discussed and a special study of T. rubrum showed that its method of attack on hair does not differ fundamentally from that of other keratinophilic fungi. It is also by means of fronds of eroding mycelium growing between the layers of keratinised cells that these fungi digest nail and hedgehog spine. Perforating organs are produced on both substrates by certain species. Eroding mycelium is uncommon in the softer keratin of callus. As frond-like mycelium is also found in a number of non-keratinophilic fungi growing on hair, and in certain other species growing in confined spaces on cellulose substrates, it is suggested that the form may be a response to the shape of the space available for growth.