Postirradiation Modification of Mutagenesis in Paramecium by Streptomycin.

Recovery in Stationary-phase Paramecia from Radiation Effects Leading to Mutation.

Recent studies1-12 of mutation induction by ionizing radiation and ultraviolet light have indicated some sort of reversibility in the mutation process and have established the important facts that alterations in postirradiation metabolism can change the amount of mutation and that a time limit exists for this change. This time limit probably occurs before the first postirradiation division in m...

Behavioral Mutants in PARAMECIUM CAUDATUM.

Mutants of Paramecium caudatum with abnormal swimming behavior or responses to cations were obtained by mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine. Some of the mutants, like pawn in P. tetraurelia, cannot swim backward and are called CNR. Seven independently obtained CNR mutants belonged to three complementation groups, designated as cnrA, cnrB and cnrC. Some characteristics of doubl...

Modification of Chromosomal Aberration Yield by Postirradiation Treatment.

Method for the simultaneous establishment of many axenic cultures of Paramecium.

A method is described for the simultaneous treatment of 42 (or more) stocks of Paramecium, and their adaptation to growth in axenic culture. Samples of dense cultures of these ciliates growing with Enterobacter aerogenes are rendered bacteria-free by migration through 2 sets of tubes containing Adaptation Medium (Peters' salts solution, stigmaterol, vitamins, and autoclaved E. aerogenes). The 2...

Tubulin polyglycylation: differential posttranslational modification of dynamic cytoplasmic and stable axonemal microtubules in paramecium.

Polyglycylation, a posttranslational modification of tubulin, was discovered in the highly stable axonemal microtubules of Paramecium cilia where it involves the lateral linkage of up to 34 glycine units per tubulin subunit. The observation of this type of posttranslational modification mainly in axonemes raises the question as to its relationship with axonemal organization and with microtubule...