Molecular and cellular events during the germination of conidia of Sporothrix schenckii.

Abstract

Hyaline, non pigmented microconidia of Sporothrix schenckii were harvested and allowed to form germ tubes in a basal medium with glucose at pH 4.0 and 25 degrees C. These conditions supported only the development of the mycelial form of Sporothrix schenckii in a reproducible, synchronized manner which allowed further analysis of the early cellular events occurring during the germination of the conidia. The relationship between macro-molecular synthesis (DNA, RNA and protein synthesis) and nuclear division, hyphal growth and septum formation were established. Following inoculation, protein synthesis was observed after 10 minutes followed by RNA synthesis, after 1 h and DNA synthesis after 2 h. The first nuclear division was observed during the 9 to 12 h interval after inoculation. Germ tube formation slightly preceeded nuclear division and was first evidenced 9 h after the induction of germination but was not completed until 12 h after inoculation. Septation was first observed in the germ tubes 0.25 micron from the mother cell-germ tube function 9 h after induction of germination.