Specific Effect of Monochromatic Light Upon Plasmolysis in Paramecium

Abstract

Investigations conducted during the last three years have shown that light of definite wave-lengths has specific effects upon the growth of organisms, e.g., yeast, paramecium and tomato rot (Colletotrichum).The organism, Paramecium caudatum, was irradiated in a quartz cell at room temperature with a Cooper-Hewitt "Lab-arc" for periods of 6 and 24 hr. and the rate of plasmolysis in sodium chloride and sucrose solutions then determined. The organisms passed through the same series of reactions in both solutions but plasmolysis occurred much more rapidly in sodium chloride than in sucrose solutions, even when the latter were of greater concentration.It would seem that the effect of light is to increase the rate of plasmolysis under all circumstances, although Packard (8) states that the permeability of the cell membrane is increased with increase of division rate in paramecium.In general there is a marked similarity between the curves showing the increase in rate of plasmolysis and those showing the effect of irradiation on the growth rate of paramecium.In most cases visible and near ultra-violet light caused an increase in the rate of plasmolysis of less magnitude than that caused by the far ultra-violet. All visible and near ultra-violet lines used, with the exception of 4960 Å, 4078 Å and 3022 Å, caused stimulation of division rate and these lines had the least effect on the rate of plasmolysis.The single green spectral line (λ = 4960 Å) had a retarding effect on growth and also caused a decided increase in plasmolysis. The lines 4078 Å and 3022 Å both caused slight decrease in division rate and slight increase in rate of plasmolysis.It would appear that, with few exceptions, the effect of monochromatic lines of the spectrum in increasing the rate of plasmolysis is greater the shorter the wave-length.It has been found that in many cases injury to an organism produces rapid increase and stimulation of growth.From the results of these experiments it would seem that when light energy is absorbed, the physiological condition of the plasma membrane changes. Apparently the conditions accompanying moderate increase in rate of plasmolysis also accompany increase in the rate of cell division in paramecium, and the conditions accompanying excessive increase in rate of plasmolysis result in decrease of growth.

The Effects of Infrared Radiation on the Ehrlich Ascites Tumor

“…Permeability increased as the duration to light was prolonged and this factor had a bearing on growth, especially in pure cultures which contained diffusible substances in, the medium. Hutchison andAshton (1929, 1931) reported that when P. caudatum was irradiated with monochromatic light certain frequencies in the red, yellow, and the near ultraviolet were found to stimulate growth.…”

Photoinhibition of Growth in Acanthamoeba castellanii Cultures

“…Light affected the amoebae either through absorption by intracellular pigment(s) or through binding to the amoebae of a photosensitizing compound in the medium. Among protozoa, photoinhibition of growth has been shown in cultures ofParamecium (9,20), Tetrahymena (7,16), Blepharisma (8), and in bleached phytoflagellates (3). The response of sarcodinid cultures to light has not been reported except for some observations of phototaxis and cytokinesis by Prescott (18) and by my preliminary reports (4,5).…”