Spore viability of microsporidian species isolated from gipsy moth larvae (Lymantria dispar) after long-term storage in liquid nitrogen

Zagreb

2015

319–324

Artikel aus einer Zeitschrift

200206515

Data on the viability of microsporidian isolates from Lymantria dispar after long-term storage in liquid nitrogen are presented. Eight microsporidian isolates from L. dispar were tested for their infectivity against L. dispar larvae: ­Vairimorpha disparis, Nosema lymantriae, Nosema portugal, Nosema sp. (Poland), Nosema sp. (Ebergassing), Nosema sp. (Germany), Nosema sp. (Schweinfurt) and Nosema sp. (Veslec). The survival of spores in liquid nitrogen was ­studied in detail for N. portugal and Nosema sp. (Ebergassing) which had been stored in liquid nitrogen almost 19 years and used for individual per oral infections while the other six isolates were used only in surface contamination per oral experiments. Our study confirms that storage in liquid nitrogen is a suitable option for long-term storage of Nosema and Vairimorpha species from lepidopteran hosts. Spores survived for up to 19 years; however, the experiments show that there is a significant loss of viability. In some cases, spores had lost viability already after 7 years in liquid nitrogen. We recommend producing fresh material every 5 years to maintain collections in liquid nitrogen. No material that had been stored in liquid nitrogen for extended periods should be used for infection experiments.
Key words: microsporidia; spore viability; long-term storage; liquid nitrogen