The energy supply for eukaryotic ciliary and flagellar movement is thought to be maintained by ATP-regenerating enzymes such as adenylate kinase, creatine kinase and arginine kinase. In this study, the energy-supplying system for the ciliary movement of Paramecium caudatum was examined. Arginine kinase and adenylate kinase activities were detected in the cilia. To demonstrate that phosphoargini...

An analysis of swimming patterns in the ciliate Paramecium shows that the ability to swim preferentially upwards (negative gravitaxis) is primarily the result of upwardly curving trajectories. The trajectory characteristics are consistent with those produced by mechanical orientation. Cell profile measurements from microscope images suggest that the characteristic front-rear body asymmetry acco...

Legionella pneumophila, the causative agent of Legionnaires' disease, replicates within alveolar macrophages and free-living amoebae. However, the lifestyle of L. pneumophila in the environment remains largely unknown. Here we established a novel natural host model of L. pneumophila endosymbiosis using the ciliate Paramecium caudatum. We also identified Legionella endosymbiosis-modulating facto...

Two ciliate protozoans, Stylonychia mytilus and Paramecium caudatum isolated from tannery effluent and cultured in a medium containing inorganic salts showed tolerance against endosulfan (1.8 μg/ml). The protozoans uptake the insecticide from the medium for utilization. Stylonychia mytilus reduced 21% endosulfan from the medium within 48 hours of inoculation of insecticide containing medium wit...

Evolutionary costs of parasite resistance arise if genes conferring resistance reduce fitness in the absence of parasites. Thus, parasite-mediated selection may lead to increased resistance and a correlated decrease in fitness, whereas relaxed parasite-mediated selection may lead to reverse evolution of increased fitness and a correlated decrease in resistance. We tested this idea in experiment...

Nuclear differentiation in exconjugants of Paramecium caudatum is closely associated with a brief localization of the postzygotic nuclei near the opposite ends of the cell, with the germinal nucleus (micronucleus) in the anterior region and the somatic nuclei (macronuclei) in the posterior region. The posterior nuclei cannot regenerate to produce micronuclei when all four anterior nuclei are re...

1. The physiological actions of HCN and its salts appear to be due (a) to the ease with which HCN molecules penetrate living cells and then ionizing, exert their influence by means of H ions and CN ions; (b) to the weakness of HCN as an acid, which permits at neutrality or at even slight alkalinity the presence of a considerable amount of free HCN molecules in the presence of their salts; (c) t...