ABSTRACT
Resistance of Nosema ceranae to different exposure conditions has been evaluated by using Sytox green and DAPI (4',6-diamidino-2-phenylindole) to test spore viability. High thermotolerance at 60 and 35 degrees C and resistance to desiccation were observed. However, a significant decrease in viability after freezing and a rapid degeneration of spores maintained at 4 degrees C were also detected.
Subject(s)
Desiccation , Hot Temperature , Microbial Viability , Nosema/physiology , Nosema/radiation effects , Stress, Physiological , Animals , Bees/microbiology , Freezing , Indoles/metabolism , Nosema/isolation & purification , Organic Chemicals/metabolism , Spores, Fungal/physiology , Spores, Fungal/radiation effects , Staining and Labeling/methodsABSTRACT
The biological cycle of Nosema spp. in honeybees depends on temperature. When expressed as total spore counts per day after infection, the biotic potentials of Nosema apis and N. ceranae at 33 degrees C were similar, but a higher proportion of immature stages of N. ceranae than of N. apis were seen. At 25 and 37 degrees C, the biotic potential of N. ceranae was higher than that of N. apis. The better adaptation of N. ceranae to complete its endogenous cycle at different temperatures clearly supports the observation of the different epidemiological patterns.
