THE EXPRESSION OF POTENTIAL COLONIZATION FACTORS OF YEASTS ISOLATED FROM FISH DURING DIFFERENT GROWTH-CONDITIONS

Three strains, Rhodotorula rubra, Rhodotorula glutinis, and Candida ze ylanoides, isolated from fish, were tested for the expression of putat ive tissue colonization factors. All strains were able to bind collage n type I, fibronectin, and laminin to various degrees after growing on various solid and broth media, while the binding to collagen type IV was sparse under all conditions tested. For the three strains tested, a very low cell surface hydrophobicity was shown for growth on various solid and broth media. Mostly, the strains also expressed a negativel y charged surface. Extracellular protease activity using different sub strates was shown for all three strains. Furthermore, two properties r elated to iron scavenging, i.e., binding of lactoferrin and production of siderophores, were also tested. For the three strains a capacity t o bind lactoferrin as well as a capacity to excrete siderophores were demonstrated. Since these different properties have been correlated to virulence and to the capacity of colonization in other organisms, we address the question of whether the expression of these properties in yeasts could contribute to colonization in fish.