Effect Of Inorganic Cations Research Articles

Electrophoretic measurements about the relation between transition voltage and ζ-potential of biological membranes

The effects of inorganic cations, n- hexanol , saccharose and 2H 2O on the electrophoretic mobility and ζ-potential of membrane vesicles from nerve myelin were measured and the results compared with the corresponding effects of the same reagents on the transition voltage, V Tr , of the nerve axon membrane. Different cation concentrations and 2H 2O affect both potentials, the ζ-potential and V Tr , in a parallel way. Saccharose and n- hexanol , however, shift V Tr but leave the electrophoretic mobility of the myelin vesicles unchanged. These results suggest that V Tr shifts are not necessarily linked to changes in the membrane surface charge density but may also be caused by an interaction between the reagent and non-polar groups of the membrane interior.

Sperm motility in the horseshoe crab, Limulus polyphemus L : II. Partial characterization of a motility initiating factor from eggs and the effects of inorganic cations on motility initiation

Egg extracts (obtained by washing intact Limulus eggs with either distilled water or artificial seawater, ASW) contain a sperm motility initiating factor (SMI). The SMI is heat stable (withstands boiling to dryness), passes through a dialysis membrane, and is retained by G-10 Sephadex (indicating a molecular weight of less than 700). Qualitative analysis (by X-ray fluorescence spectroscopy) and quantitative analysis (by atomic absorption spectroscopy) of SMI extracts revealed the presence of four divalent cations (Ca, Mg, Ni, and Cu) and one monovalent cation (K) that affect sperm motility. When assayed individually at high concentrations, all of the divalent cations initiate sperm motility and K + inhibits motility initiation by the divalent cations. However, none of the divalent cations are present at concentrations high enough to produce the observed SMI activity, and since K + is present when motility is initiated by SMI, K + must not normally be an inhibitor. Therefore, if inorganic cations are involved in normal sperm motility initiation in Limulus, they are acting in conjunction with some other low molecular weight factor.

Effect of inorganic cations on the biocidal and cellular acitivity of glutaraldehyde.

Increased bactericidal activity was observed on addition of inorganic cations to both acid and alkaline glutaraldehyde solutions. Mg2+ ion in particular potentiated activity and this was attributed to cell surface effects due to osmotic forces resulting in greater uptake of disinfectant, reduction in cell volume and interference with enzyme activity associated with the cell wall.

Effects of Inorganic Cations on Ethephon-induced Increases in Membrane Permeability 1

Abstract Treatment of beet root slices (Beta vulgaris L.) with (2-chloroethyl)phosphonic acid (ethephon) at 100 ppm increased membrane permeability 7-fold as indicated by betacyanin leakage. Leakage was much greater at higher concentrations of ethephon. Divalent and trivalent cations (Ca++, Mg++, La+++) prevented the effects of ethephon on membrane leakage without altering the rate of ethylene evolution. The monovalent cations (K+, Na+, NH4+) were not effective in relieving the ethephon effect.

The effect of inorganic cations on the inhibition and stimulation of protease activity by soil humic acids

The extent to which salts relieved the inhibition by humic acids of a given protease was independent of the nature of the inorganic anion added but depended upon the nature and concentration of the inorganic cation; salts of divalent cations were more effective than those of monovalent cations but in all cases the concentrations of cations far exceeded those of the humic acids. Pronase and carboxypeptidase activities were not affected by the order in which each enzyme was preincubated with humic acid and cation (Mg 2, K +). However preincubation of trypsin with MgCl 2 or KC1 before addition of humic acid caused a greater decrease of enzyme inhibition than when enzyme was preincubated with humic acid first. In contrast to Pronase and carboxypeptidase, trypsin reacted with humic acid to form an insoluble complex of low activity. The activity was increased by Mg 2+ and Na + ions due to displacement of enzyme from the complex into solution.

EFFECT OF INORGANIC CATIONS ON BACTERICIDAL ACTIVITY OF ANIONIC SURFACTANTS.

Voss, J. G. (Procter & Gamble Co., Cincinnati, Ohio). Effect of inorganic cations on bactericidal activity of anionic surfactants. J. Bacteriol. 86:207-211. 1963.-The bactericidal effectiveness of two alkyl benzene sulfonates and of three other types of anionic surfactants against Staphylococcus aureus is increased in the presence of low concentrations of divalent cations, especially alkaline earths and metals of group IIB of the periodic table. The cations may act by decreasing the negative charge at the cell surface and increasing adsorption of the surfactant anions, leading to damage to the cytoplasmic membrane and death of the cell. Increased adsorption of surfactant is also found with Escherichia coli, but does not lead to death of the cell.