QUANTIFICATION OF THIGMOTROPISM (CONTACT SENSING) OF CANDIDA-ALBICANSAND CANDIDA-TROPICALIS

To quantify the thigmotropism, we adapted the our previous method usin g a chemotaxifilter system in combination with a bioluminescent adenos ine triphosphate (ATP) assay based on firefly luciferase-luciferin sys tem and analyzed the relationship between the ability of germ tube for mation and thigmotropism of C. albicans and C. tropicalis. Both the ab ility to form germ tube and the amount of hyphae exhibiting thigmotrop ism varied depending upon both the species and strains of Candida. C. albicans formed more germ tubes than C. tropicalis. A good correlation was observed between the ability to form a germ tube and the capacity for thigmotropism, and the results gave a level of significance (p < 0.05). Further, SEM observation revealed that relatively long hyphae o f C. tropicalis with penetrated through the pores of filter membrane. This phenomenon may be of importance in the development of pathogenesi s of C. tropicalis as well as C. albicans.