How can a tick be preserved for research? - briefly
Preservation typically involves immersion in 70–95 % ethanol, which maintains morphological integrity and DNA quality, or rapid freezing at –80 °C for optimal nucleic‑acid retention. For long‑term storage, specimens can be transferred to 100 % ethanol after initial fixation and kept at low temperature.
How can a tick be preserved for research? - in detail
Collect specimens with fine forceps or a vacuum aspirator, avoiding damage to the mouthparts and legs. Transfer each individual into a pre‑labeled microcentrifuge tube containing the chosen preservative. Ensure labels include species, collection site, date, and collector’s name.
Kill the arthropod quickly to prevent degradation. Acceptable methods include immersion in 70 % ethanol for 1–2 min, exposure to CO₂ for 5 min, or placement on a cold plate (−20 °C) for 10 min. Immediately after killing, move the tick into a long‑term storage solution.
Choose a preservation medium based on downstream analyses:
- 70 % ethanol – suitable for morphological examination and most DNA extractions. Store tubes at 4 °C for up to six months; replace with 95–100 % ethanol for longer periods to prevent water loss.
- RNAlater – stabilizes RNA for transcriptomic work. Submerge the specimen in at least 5 × its volume, incubate at 4 °C for 24 h, then transfer to −80 °C for indefinite storage.
- Freezing – optimal for proteomics and metabolomics. Snap‑freeze in liquid nitrogen or dry ice, then store at −80 °C. Avoid repeated thaw cycles.
- Formalin (4 % buffered) – preserves tissue architecture for histology. Fix for 24 h at room temperature, then rinse and transfer to 70 % ethanol for storage. Not recommended for molecular assays.
If the study requires slide mounting, dehydrate the specimen through an ethanol series (70 %, 80 %, 95 %, 100 % each for 10 min), clear in xylene, and embed in Canada balsam or a synthetic resin. Seal the cover slip with nail polish to prevent desiccation.
Maintain a chain‑of‑custody log that records each handling step, preservative changes, and storage conditions. Periodically inspect tubes for evaporation or contamination; replenish ethanol or RNAlater as needed. Follow institutional biosafety protocols when handling pathogen‑carrying ticks, using gloves, lab coat, and a biosafety cabinet when appropriate.