How should a tick be preserved for analysis? - briefly
Preserve the specimen in 70 % ethanol and keep it refrigerated (≈4 °C) until processing. Avoid freezing, drying, or exposure to high temperatures, which can compromise DNA and pathogen integrity.
How should a tick be preserved for analysis? - in detail
Preserving a tick for laboratory examination requires rapid stabilization of both morphological features and molecular constituents. The following protocol outlines optimal practices from collection to long‑term storage.
After removal, place the specimen in a breathable container (e.g., a sterile paper envelope) to prevent moisture accumulation. Immediately record collection data: date, location, host species, and feeding stage. Label the container with this information using waterproof ink.
Choose a preservation method based on the intended analyses:
- Freezing at –80 °C – maintains DNA, RNA, and protein integrity; suitable for pathogen detection and transcriptomics. Transfer the tick directly from the field to a portable dry‑ice container, then to a laboratory ultra‑low freezer within 24 h. Avoid repeated thaw‑freeze cycles.
- 70 % ethanol – preserves external morphology and most nucleic acids; appropriate for taxonomic studies and PCR‑based pathogen screening. Submerge the specimen in enough ethanol to cover it completely; replace ethanol after 24 h to remove water. Store at 4 °C for short‑term, –20 °C for extended periods.
- RNAlater™ – stabilizes RNA without freezing; ideal for transcriptomic investigations. Immerse the tick in a sufficient volume of the solution, incubate at 4 °C for 24 h, then transfer to –20 °C for long‑term storage.
- Formalin (10 % neutral buffered) – fixes tissues for histopathology; compromises nucleic acid recovery. Fix for 24 h at room temperature, then rinse and store in 70 % ethanol at 4 °C if further molecular work is not required.
For combined morphological and molecular studies, a two‑step approach is recommended: fix the tick in 70 % ethanol for 48 h, then transfer to –80 °C. This sequence preserves structural details while maintaining nucleic acid quality.
During transport, maintain the chosen temperature regime using insulated coolers, dry ice, or portable freezers. Verify that containers remain sealed and that temperature loggers record conditions throughout shipment.
Prior to analysis, allow frozen specimens to equilibrate on ice to prevent thermal shock. For ethanol‑preserved samples, remove excess liquid by gentle blotting; avoid crushing the exoskeleton. When extracting nucleic acids, follow manufacturer protocols that account for the presence of ethanol or preservatives.
Adherence to these steps ensures reliable results across taxonomic identification, pathogen detection, and molecular profiling.