1. Prepare a 10% (v/v) sterile DMSO solution in fresh ATCC Medium 355.xa0
2. Transfer a culture at peak density to centrifuge tubes and centrifuge at 525 x g for 5 minutes.
3. Remove the supernatant and resuspend the cells in ATCC medium 355 to a concentration of 2 x 10⁶ to 2 x 10⁷ cells/mL.
4. Mix the cell preparation and the DMSO in equal portions. Thus, the final concentration will be between 10⁶ and 10⁷ cells/mL and 5% (v/v) DMSO.
5. Distribute the cell suspension in 0.5 mL aliquots into 1.0-2.0 mL sterile plastic screw-capped cryules (special plastic vials for cryopreservation).xa0 The time from the mixing of the cell preparation and DMSO stock solution before the freezing process is begun should be no less than 15 min and no longer than 30 min.
6. Place the vials in a controlled rate freezing unit.xa0 From room temperature cool at -1°C/min to -40°C.xa0 If the freezing unit can compensate for the heat of fusion, maintain rate atxa0-1°C/min through the heat of fusion.xa0 At -40°C plunge into liquid nitrogen. Alternatively, place the vials in a Nalgene 1°C freezing apparatus.xa0 Place the apparatus at -80°C for 1.5 to 2 hours and then plunge ampules into liquid nitrogen.xa0 (The cooling rate in this apparatus is approximately -1°C/min.) xa0
7. The frozen preparations are stored in either the vapor or liquid phase of a nitrogen freezer.
8. 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 just sufficient to cover the frozen material. Do not agitate the vial.
9. Immediately after thawing, aseptically remove the contents of the ampule and inoculate into 5 mL of fresh ATCC medium 355 in a 16 x 125 mm screw-capped test tube. Incubate upright at 25°C with caps screwed on tightly.

Figueiredo EN, et al. Enzymes of the ornithine-arginine metabolism of trypanosomatids of the genus Crithidia. J. Protozool. 25: 546-549, 1978.

De Menezes MC, Roitman I. Nutritional requirements of Blastocrithidia culicis, a trypanosomatid with an endosymbiont. J. Protozool. 38: 122-123, 1991.

Faria e Silva PM, et al. Herpetomonas roitmani (Fiorini et al., 1989) n. comb.: a trypanosomatid with a bacterium-like endosymbiont in the cytoplasm. J. Protozool. 38: 489-494, 1991. PubMed: 1920148

Garcia LA, Roitman I. Auxotrophic mutants of Crithidia fasciculata. J. Parasitol. 76: 739-740, 1990. PubMed: 2120414

Ferone R, Roland S. Dihydrofolate reductase: thymidylate synthase, a bifunctional polypeptide from Crithidia fasciculata. Proc. Natl. Acad. Sci. USA 77: 5802-5806, 1980. PubMed: 6934511

Gueugnot J, et al. Etude comparative de la fixation de lectines ur les membranes de quatre expeces de Crithidia. Protistologica 16: 33-38, 1980.

Bacchi CJ, et al. Polyamine function in trypanosomatids: activation of cytoplasmic alpha-glycerophosphate dehydrogenase by cationic trypanocides. Adv. Polyamine Res. 2: 129-138, 1978.

Clark CG. Riboprinting: A tool for the study of genetic diversity in microorganisms. J. Eukaryot. Microbiol. 44: 277-283, 1997. PubMed: 9225441

Coombs GH. Proteinases of Leishmania mexicana and other flagellate protozoa. Parasitology 84: 149-155, 1982. PubMed: 6460959

Leon W, et al. Toxicity of 4-nitroquinoline l-oxide for Crithidia fasciculata. J. Protozool. 22: 277-280, 1975. PubMed: 50443

Higa AI, et al. Some properties of NAD-specific glutamate dehydrogenase from Crithidia fasciculata. J. Gen. Microbiol. 113: 429-432, 1979.

Simione FP Jr., et al. The use of plastic ampoules for freeze preservation of microorganisms. Cryobiology 14: 500-502, 1977. PubMed: 891238

Branquinha MH, et al. Ubiquity of cysteine-and metalloproteinase activites in a wide range of trypanosomatids. J. Eukaryot. Microbiol. 43: 131-135, 1996. PubMed: 8720943

Dollahon NR, et al. Herpetomonas megaseliae, Crithidia fasciculata, and Leptomonas collosoma (Kinetoplastida, Trypanosomatidae) in feces of lizards fed culture forms of the flagellates. J. Protozool. 30: 58-62, 1983.

Bacchi CJ, et al. Polyamines in trypanosomatids. J. Bacteriol. 131: 657-661, 1977. PubMed: 885842

Cosgrove WB, et al. Effects of hydroxyurea on Crithidia fasciculata. J. Protozool. 26: 643-648, 1979. PubMed: 94609

Marr JJ. Crithidia fasciculata: regulation of aerobic fermentation by malic enzyme. Exp. Parasitol. 33: 447-457, 1973. PubMed: 4146226

Russell DG, et al. Tubulin heterogeneity in the trypanosome Crithidia fasciculata. Mol. Cell. Biol. 4: 779-790, 1984. PubMed: 6717441

Galinari S, Camargo EP. Trypanosomatid protozoa: survey of acetylornithinase and ornithine acetyltransferase. Exp. Parasitol. 46: 277-282, 1978. PubMed: 569594

Goncalves de Lima VM, et al. Five trypanosomatid species of insects distinguished by isoenzymes. J. Protozool. 26: 648-652, 1979. PubMed: 161788

Fish WR, et al. The cyclopropane fatty acid of trypanosomatids. Mol. Biochem. Parasitol. 3: 103-115, 1981. PubMed: 7254247

Freymuller E, Camargo EP. Ultrastructural differences between species of trypanosomatids with and without endosymbionts. J. Protozool. 28: 175-182, 1981. PubMed: 7024533

Manaia AC, Roitman I. Effect of ethidium bromide on the oxidative metabolism and enzyme profiles of Crithidia fasciculata. J. Protozool. 24: 192-195, 1977. PubMed: 864623

Alfieri SC, Camargo EP. Trypanosomatidae: isoleucine requirement and threonine deaminase in species with and without endosymbionts. Exp. Parasitol. 53: 371-380, 1982. PubMed: 6806116

Marr JJ, et al. Crithidia fasciculata: appearance kinetics of intermediates and regulation of aerobic fermentation. Exp. Parasitol. 42: 322-330, 1977. PubMed: 18361

Shapiro A, et al. Dense Crithidia growth and heme sparing: relation to Fe, Cu, Mo chelation. J. Protozool. 25: 530-534, 1978. PubMed: 33264

Paulin JJ. Crithidia fasciculata: Reconstruction of the mitochondrion based on serial thick sections and high-voltage electron microscopy. Exp. Parasitol. 41: 283-289, 1977. PubMed: 321237

Shapiro A, et al. Rapid in vitro prescreen for chelators as potential trypanocides based on growth of Crithidia fasciculata. J. Protozool. 28: 370-377, 1981. PubMed: 7310745

Teng SC, et al. A new non-LTR retrotransposon provides evidence for multiple distinct site-specific elements in Crithidia fasciculata miniexon arrays. Nucleic Acids Res. 23: 2929-2936, 1995. PubMed: 7659515

Sontheimer RD, Gilliam JN. An immunofluorescence assay for double-stranded DNA antibodies using the Crithidia luciliae kinetoplast as a double-stranded DNA substrate. J. Lab. Clin. Med. 91: 550-558, 1978. PubMed: 347011

Gorin PA, et al. Structure of the D-mannan and D-arabino-D-galactan in Crithidia fasciculata: changes in proportion with age of culture. J. Protozool. 26: 473-478, 1979. PubMed: 536936

Glassberg J, et al. Isolation and partial characterization of mutants of the trypanosomatid Crithidia fasciculata and their use in detecting genetic recombination. J. Protozool. 32: 118-125, 1985. PubMed: 3857343

Camargo EP, et al. Electrophoretic analysis of endonuclease-generated fragments of k-DNA, of esterase isoenzymes, and of surface proteins as aids for species identification of insect trypanosomatids. J. Protozool. 29: 251-258, 1982. PubMed: 6284925

Da Silva JB, Roitman I. Effect of temperature and osmolarity on growth of Crithidia fasciculata, Crithidia hutneri, Crithidia thermophila, and Herpetomonas samuelpessoai. J. Eukaryot. Microbiol. 29: 269-272, 1982.

Fernandes O, et al. Mini-exon gene sequences define six groups within the genus Crithidia. J. Eukaryot. Microbiol. 44: 535-539, 1997. PubMed: 9435125

Cho J, Eichinger D. Crithidia fasciculata induces encystation of Entamoeba invadens in a galactose-dependent manner. J. Parasitol. 84: 705-710, 1998. PubMed: 9714198

Baker H, et al. Biopterin content of human and rat fluids and tissues determined protozoologically. Am. J. Clin. Nutr. 27: 1247-1253, 1974. PubMed: 4447093

Nucleotide (GenBank) : Y08233 C.fasciculata gene encoding ornithine decarboxylase.