Changes in transfer ribonucleic acid population of Acanthamoeba castellanii during growth and encystment.

Fifteen aminoacyl-transfer ribonucleic acids (tRNA's) from vegetative cells (trophozoites) and mature cysts of Acanthamoeba castellanii were compared by reversed-phase 5 chromatography. Little or no differences were detected in reversed-phase 5 chromatography elution profiles of alanyl-, arginyl-, isoleucyl-, phenylalanyl-, prolyl-, seryl-, threonyl-, tryptophanyl- and valyl-tRNA's. Significant differences in the relative proportions of isoaccepting species of leucyl-, lysyl-, methionyl-, aspartyl-, histidyl-, and tyrosyl-tRNA's were observed. Based upon the criterion of cyanogen bromide reactivity with the modified nucleoside queuosine, the content of queuosine in aspartyl-tRNA of A, castellanii is significantly greater in mature cysts than in trophozoites. The similarity of change in reversed-phase 5 chromatography elution profiles of aspartyl-, histidyl-, and tyrosyl-tRNA suggests that a common mechanism is responsible for alterations in the chromatographic patterns.