STIMULI FOR THE INVITRO GERMINATION AND INHIBITION OF NOSEMA-LOCUSTA (MICROSPORA, NOSEMATIDAE) SPORES

Factors influencing the germination of spores of the microsporidian Nosema locustae were investigated. When exposed to solutions of monovalent salts, spores germinated in the presence of sodium (19.5% germination) and potassium (21% germination), both at pH 9.2, but not in the presence of lithium. Between 12 and 16% of spores could also be induced to germinate following a 1-month-long incubation in polyethylene glycol before being transferred to Tris-NaCl, pH 9.2. In addition, a brief period of desiccation followed by rehydration in Tris-NaCl resulted in 30.5% germination, the maximum level achieved in this study. In contrast, freeze-drying inhibited germination, as did a 5-min exposure to UV light, while germination was also adversely affected by exposure to temperatures above 40°C for even brief periods (>5 min). It is concluded that a number of stimuli (or their interactions) are required to induce germination, some of which are yet to be elucidated. © 1990.