The oligodynamic effect

The oligodynamic effect (from the Greek. oligos - small and dynamis - force) - the effect is very small concentration of positive ions on biological objects.
The concept of the oligodynamic actions occurred in 1893, when the botanist Negele (C. Naegeli) found a negative influence on the growth of algae in the water in which plunged pieces of copper or silver. Purchased this water harmful properties applied to glass dish in which water was kept; the presence of organic substances in the colloidal state is greatly reduced O. D. water.
The oligodynamic effect depends on the presence in water of cations of metals with high normal electrode potentials (Ag+, Hg++ and C++), and some non-metal ions, with the ability to inactivate the enzymes active groups which are on the surface of biological substrates (bacteria, cells). Leitner (N. Leitner) proved that O. D. water in which they were immersed pieces of metals depends on the specific ion concentration: to suppress livelihoods 300 000 microbial bodies of E. coli in 1 ml takes approximately 0.003 mg of silver on 1 l of water, i.e. for each bacterium accounts for about 57-U of silver atoms. It is established that at O. D. the process of concentration of gram-positive ions on the surface of cells. According to Drexel (O. Drechsel, 1921), cells die, if the concentration data ions in the water is 1 : 108-105; while in the cells metal content reaches of 0.02-4% of their dry weight. Thus, when O. D. has selective adsorption process, where the metal ions bind located on the surface of microbial cells negatively charged groups playing a crucial role in metabolism and energy (available carbonyl, sulfhydryl groups and others).
Repressed under the oligodynamic effect of the positive ion cell viability, microorganisms or enzymes can recover adding substances with strong negatively charged groups. To such substances include hydrogen sulfide, which is easily restored livelihoods bacteria exposed to ions (salts) of silver and mercury.
The oligodynamic effect metals, particularly silver, finds application in space medicine to prevent damage of water resources in conditions of prolonged space flight.