Preservation of encysted polytomella

Area of Science:

• Microbiology
• Cryobiology

Background:

• Polytomella species are unicellular green algae.
• Effective long-term storage methods for microbial cysts are crucial for research and conservation.

Purpose of the Study:

• To evaluate the efficacy of different storage conditions and substrates for preserving Polytomella cysts.
• To determine the impact of cryopreservation on cyst viability and excystment rates.

Main Methods:

• Cysts of Polytomella parva and Polytomella caeca were dried on filter paper, silica gel, or without substrate.
• Dried cysts were stored at cryogenic temperatures (-30°C and below -70°C) and subjected to accelerated storage testing at elevated temperatures.
• Cyst recovery and excystment rates were assessed after storage.

Main Results:

• Viable cysts were recovered after 7 days of cryogenic storage regardless of substrate.
• Shredded filter paper proved to be the superior substrate, especially for long-term storage at -30°C.
• Storage on filter paper below -70°C and immediate rehydration after drying resulted in the most rapid recovery.

Conclusions:

• Cryopreservation is a viable method for long-term storage of Polytomella cysts.
• Filter paper is an effective substrate for cryopreservation, enhancing cyst survival and recovery.
• Storage temperature and rehydration timing significantly influence excystment success.