In this paper we demonstrate the presence and localization of calmodulin, a calcium-dependent regulatory protein, in the ciliated protozoan Paramecium tetraurelia. Calmodulin is demonstrated by several criteria: (a) the ability of whole cell Paramecium extracts to stimulate mammalian phosphodiesterase activity, (b) the presence of an acidic, thermostable, 17,000-dalton polypeptide whose mobilit...

Our goal is to control microorganisms as microscale smart robots for various applications. In this paper, we introduce two approaches: a novel visual feedback control system for Paramecium cells and a dynamics model of Paramecium galvanotaxis (intrinsic reaction to electrical stimulus) for procise actuation. In the former part, we propose a microrobotic control system of cells using high-speed ...

The toxicity of 14 commercial natural dyes which are widely used as food additives in Japan was studied on Paramecium caudatum. Laccaic acid and capsanthin were found to be very toxic to Paramecium caudatum. Some of the commercially available carminic acid and crocin were also toxic. The inhibitory effect of natural food dyes on leucine aminopeptidase, acid phosphatase and esterase in vitro was...

In concentrations of 1:10(4), 1:10(5), 1:10(6), in alkaline solution with a hydrogen ion concentration approximating that characteristic of normal human blood, thyroxin acts like total thyroid in accelerating certain metabolic processes in Paramecium, notably those connected with the phenomena of excretion. Unlike total thyroid, thyroxin depresses the division rate of Paramecium, the degree of ...

Under axenic growth all 14 syngens of Paramecium aurelia have 4 types of esterases. The three major types (A, B and cathodal C) vary independently in electrophoretic mobility among the syngens. Using these three esterases, stocks can be keyed to a syngen, except for the groupings 1-3-5 and 7-13. Using 5 other enzymes only syngens 1 and 5 cannot be distinguished. Most syngens differ from each ot...

* This paper is a part of a dissertation presented for the degree of Doctor of Philosophy at Yale University. t Present address: Eastern States Farmers Exchange, West Springfield, Massachusetts. I Beale, G. H., The Genetics of Paramecium aurelia (Cambridge University Press, 1954). 2 Ephrussi, B., Nucleo-cytoplasmic Relations in Microfrganisms (Oxford: Clarendon Press, 1953). 3 Mitchell, M. B., ...

Instead of zoochlorella endosymbionts, magnetic micro-beads (Dynabeads) was microinjected into P. bursaria white strain which can resultantly response to magnetism. The system may provide an interesting artificial endosymbiosis system.

We have investigated the bioconvection of Paramecium tetraurelia in high-density suspensions made by centrifugal concentration. When a suspension is kept at rest in a Hele-Shaw cell, a crowded front of paramecia is formed in the vicinity of the bottom and it propagates gradually toward the water-air interface. Fluid convection occurs under this front, and it is driven persistently by the upward...

The factors maintaining the cytoplasmically inherited killer trait in populations of Paramecium tetraurelia and Paramecium biaurelia were examined using, in part, computer simulation. Frequency of the K and k alleles, infection and loss of the endosymbionts, recombination during conjugation and autogamy, cytoplasmic exchange and natural selection were incorporated in a model. Infection during c...

Cells of Paramecium caudatum in the immaturity period of the life cycle contain substances which repress the expression of mating ability when introduced into mature cells. When 5 x 10 /tm of immature cytoplasm were injected into mature cells, loss of mating ability occurred and it continued for more than 15 fissions after the injection. The effective substances are contained in the soluble fra...