Figure 1.

Extracellular [Ca²⁺] Affects Cathodal Emergence of C. albicans Hyphae but Not Final Orientation in an Applied Electrical Field

(A) Tracings of individual hyphae grown in varying [Ca²⁺] were superimposed at a common point of origin for illustrating the distribution of hyphal orientation under the conditions used. Yeast cells adhered to poly-L-lysine-coated glass slides were grown in Ca²⁺-depleted, hypha-inducing medium for 6 hr and either not exposed to an electrical field (1) or exposed to an electrical field of 10 V/cm (2) supplemented with 1 mM CaSO₄ (3), 2 mM BAPTA (a Ca²⁺ chelator) (4) or 2 mM BAPTA + 3 mM (excess) CaSO₄ (5).

(B) Germ-tube-emergence angles relative to the cathode for cells in Figure 1A, where 100% cathodal orientation denotes perfect cathodal orientation, −100% denotes anodal orientation, and 0% is obtained for a randomly orientated population. Each error bar shows the SD of the mean values obtained from three independent experiments.

(C) The tropic growth of hyphal tips was not affected by extracellular [Ca²⁺]. The final angles of hyphal tips after 6 hr growth in an electrical field were cathodally oriented irrespective of germ-tube-emergence angle. Hyphae reoriented when the field polarity was reversed (arrows), even in low [Ca²⁺] medium. The scale bar represents 10 μM.