A model is presented suggesting the interaction of CO~ and bicarbonate on lipids of the cell membrane, The inteffacial tensions between water and oil (ber~zene) phases were measured using the stalagmometer and the sessile drop methods. Effects of electrolyte solutions and of CO~ on molecular arrangement ~at the interface were calculated. Chloride solutions against oleie acid in benzene 'produced little decrease in inteffacial tension from that measured for pure water against the oil phase. Presence or absence of CO2 caused no change in interfacial tension of water or chloride solutions against the oil phase. Bicarbonate salts in the absence of CO2 caused marked decreases in inteffacial tension from that measured for water or chloride solutions. Concomitant with this decrease in inteffacial tension were an increase in hydration of the interface and changes in molecular spacings O f the lipid. This hydration may be considered as reflecting a more ionic-permeable cell membrane. The addition of CO~ to the bicarbonates caused an increase in interfaeial tension of the model, approaching that of the chlorides, with decreased hydration of the interface. Viewed as occurring at the cell membrane this would make the lipid more continuous and decrease the ease of ionic penetration. In this way the action of bicarbonates and CO2 at the interface suggests an explanation of the action of CO~ on the cell. I N T R O D U C T I O NIncreased tensions of CO 2 have marked effects on living systems. Perhaps the most prominent alteration is decreased excitability of the organism or cell. This action of CO 2 is interwoven with the problem of narcosis and remains to be explained. Investigations concerned with CO~ effects have led to the question as to whether CO 2 as a gas, bicarbonate ions, or hydrogen ions are responsible for the cellular changes (e.g., Tomita, 1935;Becker, 1936; Niedergerke and St/~mpfli, 1953; and McElroy, Gerdes, and Brown, 1958). Numerous and varied biological effects of CO2 have recently been reviewed by Loomis (1957).

No abstract

Diffusion of the chloride salts of Li, Na, K, Rb, and Cs from water into 1-butanol and from 1-butanol into water was examined at temperatures from 13-40 degrees C. Distribution coefficients, interfacial transfer coefficients, Arrhenius activation energy, free energy of activation, enthalpy, and entropy of activation were determined for the diffusion of these salts across the alcohol-water interface. The results indicate that the entropy decrease made the major contribution to the change in the free energy of activation.

SYNOPSIS. Experiments were undertaken to examine and to quantitate the effect of CO2 upon movement, contractile vacuole activity, cellular volume and shape, and survival of Paramecium multimicronucleatum. Paramecia tolerated pressures of CO* up to 1 atmosphere for at least 24 hours. Above 1 atmosphere survival was inversely related to pressure of CO2. Increasing CO2 tensions slowed forward movement and altered length and width of the spiral paths. Pulsation rates of anterior contractile vacuoles diminished as the CO2 pressure increased. At 20 psi of CO2 vacuoles ceased to function. Paramecia retained their volume and shape when exposed to high CO2 tensions. Removal of CO2 from the medium decreased speed and length of spirals and caused an increase in cellular volume. These effects of pressure variation of “CO” are examined in terms of the ability of COS to expand the volume of hydrocarbons upon dissolving into these compounds and in terms of bicarbonate competing for cations at the cell membrane.

Force-area, surface potential-area and viscosity-surface pressure data were obtained for stearic acid monolayers on water and heavy water @OD) at 15, 25 and 37°C. These dzta show that substitution of DOD for HOH increases the surface potential of stearic acid monolayers and increases surface viscosity. However, no differences in force-area curves were detected between monolayers on HOH and DOD.