Acanthamoeba
- Acanthamoeba sp.
- Acanthamoeba castellani
- Acanthamoeba hatchetti
[ref. ID; 7117]
Test system
Stress-Induced Pseudocyst formation
Strains
Three clinically-derived isolates (V/01; B/04; N/05) from corneal scrapes of keratitis patients from the Czech Republic and one environmental (RB728/07SR) isolated from an outdoor swimming pool in the Solvak Republic.
Toxicants
- Stress chemicals; Acetone, Methanol and DMSO.
- Resistance of pseudocysts and cyst; Heat, acids and alkali, and desiccation.
Test design
- Stress chemicals: Trophozoites of all isolates were grown on cover slips in sex-well microplates to the late exponential phase of growth (nearly a confluent monolayer). For encystation induction, the spent PYG was quantitatively poured off and the attached trophozoites were immediately overlaid with non-nutrient Neff's encystment medium (NEM) [0.1M KCl/8 mM MgSO4 + 7 H2O/0.4 mM CaCl2 + 2 H2O/1mM NaHCO3/20 mM ammediol (2-amino-2methyl-1,3-propanediol; Sigma, USA), pH 8.8] at 37 degrees C. For stress response induction, NEM + chemicals addition (concentration 0.1-50% v/v).
- Resistance test:
Thermotoletance test: 40-65 degrees C in water bath for 5 or 10 min.
Sensitivity to acids and alkali: Citrate-phosphate buffer (0.1M citric acid/0.2M dibasic sodium phosphate, pH range 3-5.5), phosphate buffer (0.2M monobasic sodium phosphate/0.2M dibasic sodium phosphate, pH range 6-8) and ammediol buffer (0.2M ammediol, pH range 9-11 adjusted with 1M NaoH) were used to prepare pH-specific non-toxic environment. Exposure period 10 min-24 hr.
Dessication: Dry at 37 degrees C for 7 days.
Measurements/observations
- Stress chemicals: Microscopy studies, Lectin-binding studies, and the cyst-specific protein (CSP21).
- Resistance test: Viability.
[ref. ID; 946]
Test system
144-hr toxicity assay
Strains
I-12 strains (from Dr. Robert J. Neff), axenically.
Toxicants
Aldrin, Atrazine, dieldrin, sevin, linuron, stam F-34, IPC, simazine, Aroclor 1254, CuSO4/5H2O, ZnSO4/7H2O, Pb(NO3)2, HgCl2
Temperature
30 degrees C.
Test design/concentrations
125 ml Erlenmeyer flasks (medium: Neff's optimal growth medium (Prescott, 1964) prepared by the method of Byers, et al. (1969)).
Measurements/observations
Inhibition of population growth.
Evaluations
Percent of control values.
[ref. ID; 1327]
Test system
72-hr acute toxicity and cross-resistance
Strains
ATCC (Rockville, Md.; #30730).
Toxicants
Potassium dimethyldithiocarbamate (MBC 350), 5% tributyl-tin neodecanoate with quaternary ammonium compounds (MBC 120), 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one (MBC 215), poly [oxyethylene (dimethyliminio) ethylene (dimethyliminio) ethylene dichoride] (MBC 115)
Temperature
25+/-1 degrees C.
Test design
Medium: Tris-buffered saline solution (TBSS: 2 mM KCl, 1 mM CaCl2, 0.5 mM MgCl2, 1 mM Tris), pH 6.8-7.2.
Measurements/observations
Population density.
Evaluations
Minimum Inhibitory Concentration (MIC).