INHIBITION BY PHOSPHOLIPIDS OF THE ACTION OF SYNTHETIC DETERGENTS ON BACTERIA

Effects of detergents on natural ecosystems and wastewater treatment processes: a review

Among the different contaminants, detergent as an important pollutant has serious risks to natural ecosystems. Furthermore, detergents can pass into the wastewater treatment plants and have bad effect on their performance. They are part of human life and consumed for different aims especially hygienic purposes. Therefore, detergent components can enter to soil and water bodies from different sources. Detergents affect fauna and flora, and they have direct and indirect effects on ecosystems. Eutrophication, foaming, and altering parameters such as temperature, salinity, turbidity, and pH are more important, and their effects need to be managed and controlled. Researchers confirmed that aerobic processes are able to degrade the most of detergents but anaerobic degradation is not possible because of restricted metabolic pathways and toxicity of them. Therefore, production of environment-friendly detergent is an important issue around the world. Graphical abstract.

THE BINDING OF FATTY ACIDS BY SERUM ALBUMIN, A PROTECTIVE GROWTH FACTOR IN BACTERIOLOGICAL MEDIA

Serum albumin is a protective bacterial growth factor; by binding traces of fatty acid in the media it permits initiation of growth by the smallest possible inocula of tubercle bacilli. Each molecule of albumin binds 3 to 6 molecules of oleic acid (1 to 2 per cent of the weight of the albumin) tightly enough to prevent bacteriostasis, and 9 molecules of oleic acid in equilibrium with a saturated neutral solution. The property requires undenatured albumin. Crystalline β-lactoglobulin has a smaller capacity, and a number of other proteins no perceptible capacity to bind oleic acid. The inhibitory effect of the commercial product Tween 80 (polyoxyethylene sorbitan monooleate) on the growth of small inocula of tubercle bacilli in liquid media is caused by its content of unesterified oleic acid (0.6 per cent by weight). Purified Tween 80, freed of this contaminating fatty acid, not only permits growth of small inocula, but protects against small amounts of added oleic acid. The implications of the binding capacity of albumin for its possible physiological significance in the animal body (transport; protection against cytotoxins), and for the structure of the protein, are briefly discussed.

Studies on the hemolytic properties of protamine

The basic protein protamine causes a rapid hemolysis when incubated with the red blood cells of many mammalian species. The age of the cells does not affect the process. Neutralization of the active side groups of the protamine molecule with formalinization demonstrates that a specific degree of charge is necessary for hemolysis, as more than 30 per cent of the guanidine groups must remain unreacted to maintain activity. Unlike the hemolysis induced by the synthetic polypeptides polylysine and polyhomoarginine, protamine hemolysis is temperature-dependent. Whole lipoprotein material derived from red blood cell membranes inhibits protamine hemolysis to a greater extent than do the membranes themselves, serum, serum protein fractions, or cholesterol. The phosphatide and protein moieties derived from the membranes are quite avid in inhibiting protamine hemolysis. A probable explanation is that intracellular aggregation of these structural elements may cause changes in electrostatic charge and surface tension which result in increased permeability. The hemolytic and antitumor cell properties of protamine could not be segregated from its animal toxicity. Despite formalinization to a degree which eliminated the former, the compound remained quite toxic to mice and rabbits.

CYTOLOGY OF CANDIDA ALBICANS AS INFLUENCED BY DRUGS ACTING ON THE CYTOPLASMIC MEMBRANE

Gale, Glen R. (Veterans Administration Hospital, Durham, N.C.) Cytology of Candida albicans as influenced by drugs acting on the cytoplasmic membrane. J. Bacteriol. 86:151-157. 1963.-An electron microscopic comparison was made of the cytological responses of Candida albicans to benzalkonium chloride, amphotericin B, and filipin, all of which are thought to exert their primary pharmacological actions on the cytoplasmic membrane of susceptible microorganisms. After 5 to 15 min of exposure to benzalkonium chloride, most of the cytoplasm became less dense, and intact nuclei, mitochondria, or intracytoplasmic membranes were not observed. The remaining dense cytoplasm contained numerous small holes. The polyene antifungal agents, amphotericin B and filipin, caused a reduction in cytoplasmic density, but had no observable effect on nuclei or mitochondria. The intervals before onset of changes induced by the polyene agents correlated with the known time-dependent binding of these drugs by cells, and the decreased electron scattering induced by all three agents was compatible with their known abilities to cause a loss of integrity of the cytoplasmic membrane with resultant leakage of cytoplasmic components. No consistent morphological effect of any of these drugs on the cytoplasmic membrane could be shown.

Mixtures of Quaternary Ammonium Compounds and Long-chain Fatty Acids as Antifungal Agents

The influence of undecylenic acid on the fungistatic effect of phenoxyethyldimethyldodecylammonium bromide (Domiphen bromide) against Trichophyton mentagrophytes was investigated. The unsaturated fatty acid was found to enhance the fungistatic activity of Domiphen bromide against this organism. The ratio of concentrations of these agents has a marked influence on the results of in vitro tests for antifungal action resulting in a completely different effect than heretofore noted in combination experiments against bacteria. The enhancing phenomenon is not particular to T. mentagrophytes , it was observed also with Candida albicans .

Cytological changes in Bacillus species in stasis and death caused by quaternary ammonium compounds

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