Mutants of Acanthamoeba castellanii Resistant to Erythromycin, Chloramphenicol, and Oligomycin

Abstract

Cell lines of Acanthamoeba castellanii resistant to erythromycin (EryR), chloramphenicol (CapR), and oligomycin (OliR) have been isolated. These may be the first such mutants for A. castellanii. These mutants have been phenotypically stable for 2 years, surviving storage and vegetative multiplication in the absence of drugs. Resistance was specific for each drug, but double mutants (e.g. EryRCapR) were obtained by stepwise selection. Mutant frequencies were determined in multiwell plates; less than 10 colony forming units (CFU/10(5) amebas were observed in wild-type populations 12 days after incubation in 500 microgram Ery/ml, 2.5 mg Cap/ml, or 15 microgram Oli/ml. After 30 days, averages of 100 CFU/10(5) amebas were observed in Ery and Cap, whereas, frequencies for Oli remained unchanged. Frequencies for EryR and CapR were consistent with rates of recovery from these drugs in batch cultures. We were unable to obtain spontaneous mutants resistant to cycloheximide, emetine, 5-fluorodeoxyuridine, or ethidium bromide. EryR, CapR and OliR could be mitochondria mutants.

Rapid Growth of Acanthamoeba In Defined Media; Induction of Encystment By Glucose‐Acetate Starvation

“…Glucose or acetate prevented encystment. Cysts could be stored on silica gels (15). They excysted in DGM-21A or B containing both glucose and acetate: we did not determine whether both carbon sources were required.…”

In Memoriam: Thomas J. Byers (1935–2003)

“…In the late 70's and early 80's, Tom's group became interested in applying traditional mutagenic/drug resistance methods to learn more about the reproductive strategy of this organism. Processes of mating, or at least hybrid fusion, were proposed; and markers to track parental genetic material were sought (Seilhamer and Byers 1978, 1982). This led to the development and application of restriction fragment length polymorphisms (RFLP) to examine mitochondrial DNA (Bogler et al 1983).…”

ATPase‐Associated Oligomycin Resistance in Acanthamoeba castellanii1

“…G creased resistance to specific antibiotics have been isolated only recently (4, 11). LittIe is known about the molecular basis of resistance.…”