Isolation |
Wild-caught Caenorhabditis elegans isolated from a compost pit,
Franconville, France Ref Troemel ER, et al. Microsporidia are natural intracellular parasites of the nematode Caenorhabditis elegans. PLoS Biol. 6: 2736-2752, 2008. PubMed: 19071962 |
Cryopreservation |
M9 buffer
KH2PO4, 3.0 g
Na2HPO4, 6.0 g
NaCl, 5.0 g
MgSO4 (1M), 1.0 ml
Distilled H2O, 1.0 L
Dissolve ingredients in 1 L of distilled water. Distribute 200 to 500 ml aliquots into appropriate sized bottles and autoclave for 15 minutes.
Harvest and Preservation
- To harvest the Nematocida culture, add 5 ml of M9 buffer to an infected NGM plate and transfer the suspension to a 15 ml centrifuge tube.
- Centrifuge at 200 x g for 5 min. Remove the supernatant, resuspend the pellet in 5 ml of M9 buffer, and repeat the centrifugation step.
- Repeat step 2 a minimum of five times in order to wash the infected worms.
- After the last wash, resupend the pellet in 1 ml of M9 buffer and transfer the suspension to a 2 ml microcentrifuge tube. Add Silicon carbide beads (BioSpec Products, Inc.) to the tube and vortex for 1 minute. Repeat the procedure 4-5 times. Filter the worm extract through a Whatman filter paper number 1 to remove eggs and any remaining intact worms.
- Perform a spore count of the worm extract and adjust the concentration to ≥ 3 x 107 spores/ml.
NOTE: If the concentration of spores is too low, harvest infected worms from additional NGM plates to yield the desired concentration.
- Mix the extract with an equal volume of M9 buffer containing 30% glycerol. The final concentration of the extract will be ≥ 1.5 x 107 spores/ml and 15% glycerol.
- Dispense 70 ml aliquots into 1.0-2.0 ml sterile plastic screw-capped cryovials.
- Place vials in a controlled rate freezing unit. From room temperature cool at -1°C/min to -40°C. If freezing unit can compensate for the heat of fusion, maintain rate at -1o C/min through heat of fusion. At -40°C plunge ampules into liquid nitrogen. Alternatively, place the vials in a Nalgene 1°C freezing apparatus. Place the apparatus at -80°C for 1.5 to 2 hours and then plunge ampules into liquid nitrogen. (The cooling rate in this apparatus is approximately -1°C/min.)
- Store frozen ampules in either the vapor or liquid phase of a nitrogen refrigerator.
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References |
Troemel ER, et al. Microsporidia are natural intracellular parasites of the nematode Caenorhabditis elegans. PLoS Biol. 6: 2736-2752, 2008. PubMed: 19071962
Nematocida parisii ERTm1 genome sequencing project Available from: NCBI BioProject
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