In Paramecium, the regeneration of a functional somatic genome at each sexual event relies on the elimination of thousands of germline DNA sequences, known as Internal Eliminated Sequences (IESs), from the zygotic nuclear DNA. Here, we provide evidence that IESs' length and sub-terminal bases jointly modulate IES excision by affecting DNA conformation in P. tetraurelia. Our study reveals an exc...

N a previous paper KIMBALL (1949) has described the induction by radiation I of changes in vigor in Paramecium aurelia which first expressed themselves in the exautogamous progeny of rayed animals. In that paper, it was assumed that the changes were due to mutations in the micronucleus. This paper will present the genetic evidence which bears on this assumption. The radiation studies suggested ...

The environment is rarely constant and organisms are exposed to temporal and spatial variations that impact their life histories and inter-species interactions. It is important to understand how such variations affect epidemiological dynamics in host-parasite systems. We explored effects of temporal variation in temperature on experimental microcosm populations of the ciliate Paramecium caudatu...

It is technically difficult to acquire large-field images under the complexity and cost restrictions of a diagnostic and instant field research purpose. The goal of the introduced large-field imaging system is to achieve a tolerable resolution for detecting microscale particles or objects in the entire image field without the field-curvature effect, while maintaining a cost-effective procedure ...

M A T I N G type determination and inheritance in Paramecium caudatum has been reported only for syngen 12 (HIWATASHI 1958). Inheritance was usually synclonal, i.e. the two clones derived from the two members of a conjugating pair are identical in mating type expression, indicating direct genic control of mating type. However the breeding analysis was incomplete and some of the observations, as...

The membrane potential responses of Paramecium caudatum to the external application of bitter substances were examined by employing conventional electrophysiological techniques. Mutant cells defective in voltage-gated Ca2+ channels were used to record the potential responses in the absence of contamination by Ca2+ action potentials. The cells produced a transient depolarization followed by a tr...

The effect of industrial sludge toxicity on the cell growth of a green paramecium, Paramecium bursaria was examined. P. bursaria cells were cultured in a lettuce medium supplemented with various concentrations of sludge suspension at 23 °C under LD (ligh and dark cycle) condition. Results suggested that P. bursaria proliferates normally even at 1.5% sludge suspension. However, 1.5x10 % sludge s...

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...

A stand of Paramecium novaurelia was found in Boston Massachusetts, USA, the first on this continent. Molecular studies (RAPD and sequencing ofrRNA [3'SSUrRNA-ITS1, 5' LSU rRNA] and COI mtDNA fragments) of P. novaurelia strains show intra-specific polymorphism within the species as strain clusters characterized by variable relationships.

initiate it may likewise be unique. At least, gene-initiated plasmagenes can be more readily assimilated into current genetic knowledge and theory which demand ultimate gene control of hereditary capacities. The cells of a multicellular organism are like the cells of a clone of unicellular organism in .their presumed identity of genes. Nevertheless, in both the Metazoan and the Protozoan persis...