Yeast cell cycle of Sporothrix schenckii.

Unbudded yeast cells from exponentially growing Sporothrix schenckii were harvested, selected by filtration and allowed to form buds in basal medium with glucose at pH 7.2. These cells undergo bud formation and cell duplication at 25 degrees C earlier than at 35 degrees C. The time of cell duplication at 25 degrees C was dependent upon the initial cell concentration. These cells carried out RNA and protein synthesis before cell evagination as early as 10 min after inoculation, and DNA synthesis during the 6 to 9 h period after inoculation, prior to nuclear division and bud formation. Nuclear division and bud formation seemed to occur concomitantly during the 9 to 12 h period after inoculation and were inhibited by the addition of hydroxyurea (0.1 M) to the medium. The preferred site for bud formation was the pole opposite the birth scar. Septum formation was evidenced at the mother cell-bud junction. A light septum first appeared in medium sized buds followed by a dark septum in large buds.