Biosafety classification is based on U.S. Public Health Service Guidelines, it is the responsibility of the customer to ensure that their facilities comply with biosafety regulations for their own country.
1.? Allow the cells to encyst.? To detach cysts from the plate flush the surface with 5 ml fresh ATCC medium 1323 (Page's Balanced Salt Solution).? Rub the surface of the plate with a spread bar to detach adhering cysts.
2.?? Transfer the liquid medium to a sterile centrifuge tube.
3.? If the cyst concentration does not exceed 2 x 106 cysts/ml adjust the suspension to that concentration.? To adjust the concentration, centrifuge at 600 x g for 5 min and resuspend the pellet in the volume of fresh medium required to yield 2 x 106.
4.? While cells are centrifuging prepare a 15% (v/v) solution of sterile DMSO as follows:? Add the required volume of DMSO to a glass screw-capped test tube and place it in an ice bath.? Allow the DMSO to solidify.? Add the required volume of refrigerated medium.? Dissolve the DMSO by inverting the tube several times.?
????? *NOTE: If the DMSO solution is not prepared on ice, an exothermic reaction will occur that may precipitate certain components of the medium.
5.? Mix the cell preparation and the DMSO in equal portions. Thus, the final concentration will be at least 106 cysts/ml and 7.5% (v/v) DMSO.? The equilibration time (the time between addition of DMSO and the start of the cooling cycle) should be no less than 15 min and no longer than 30 min.
6.?? Dispense in 0.5 ml aliquots into 1.0 - 2.0 ml sterile plastic screw-capped cryules (special plastic vials for cryopreservation).
7.?? Place the vials in a controlled rate freezing unit.? From room temperature cool at -1°C/min to -40°C.? If the freezing unit can compensate for the heat of fusion, maintain rate at??????? -1°C/min through the heat of fusion.? At -40°C plunge 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.) ?
8.? The frozen preparations are stored in either the vapor or liquid phase of a nitrogen freezer.
9.?? To establish a culture from the frozen state place an ampule in a water bath set at 35°C (2-3 min). Immerse the vial to a level just above the surface of the frozen material. Do not agitate the vial.
10.????????? Immediately after thawing, aseptically remove the contents of the ampule and distribute to the center of a fresh plate of ATCC medium 711.? Distribute the material evenly over the plate using a spread bar.? Incubate at 25°C.
Jenkins WS. The role of the contractile vacuole in excystment of Acanthamoeba polyphaga (Puschkarew) Page. J. Protozool. 23: 24A, 1976.
Daggett PM, et al. Distribution and possible interrelationships of pathogenic and nonpathogenic Acanthamoeba from aquatic environments. Microb. Ecol. 8: 371-386, 1982.
Daggett PM, et al. A molecular approach to the phylogeny of Acanthamoeba. Biosystems 18: 399-405, 1985. PubMed: 4084681
Stothard DR, et al. The evolutionary history of the genus Acanthamoeba and the identification of eight new 18S rRNA gene sequence types. J. Eukaryot. Microbiol. 45: 45-54, 1998. PubMed: 9495032
Stothard DR, et al. Fluorescent oligonucleotide probes for clinical and environmental detection of Acanthamoeba and the T4 18S rRNA gene sequence type. J. Clin. Microbiol. 37: 2687-2693, 1999. PubMed: 10405422
Ledee DR, et al. Advantages of using mitochondrial 16S rDNA sequences to classify clinical isolates of Acanthamoeba. Invest. Ophthalmol. Vis. Sci. 44: 1142-1149, 2003. PubMed: 12601042
Nucleotide (GenBank) : AF019052 Acanthamoeba polyphaga Panola Mountain 18S ribosomal RNA gene, partial sequence.
