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.

GRANULAR PNEUMOCYTES: ELECTRON MICROSCOPIC EVIDENCE OF THEIR EXOCRINIC FUNCTION

The contents of the lamelar bodies of granular pneumocytes are normally released into the alveolar lumen. Exposure of guinea pigs to an atmosphere containing carbon dioxide causes the formation of abnormal lamellar bodies and a significant increase in the pulmonary surface tension. The eventual return to a normal pulmonary surface tension coincides with the formation of normal lamellar bodies.

OXYGEN-STABLE HEMOLYSINS OF GROUP A STREPTOCOCCI. II. CHROMATOGRAPHIC AND ELECTROPHORETIC STUDIES

The oxygen-stable streptococcal hemolysins, which can be induced by a number of diverse substances, have been studied. Differences among these hemolysins have been found in electrophoresis, chromatography, pH stability, and susceptibility to some organic solvents and to an enzyme, RNAase. These properties have in each case been found to characterize the inducing substances as well. In a number of instances it has been found possible to incubate one inducer with the hemolysin induced by another of these agents and then, after appropriate fractionation, to find hemolytic activity in the fraction containing the fresh inducer. These observations suggest that the oxygen-stable streptococcal hemolysins are constituted as carrier-hemolysin complexes, the carriers being the set of molecular species effective as inducers, and the prosthetic group being transferred from one carrier to another under appropriate conditions. After transfer of the hemolytic moiety from a hemolysin molecule which is susceptible to inactivation by a given agent or set of conditions to a carrier which is not itself significantly affected by this agent, the new, derived, hemolysin has been found not to be inactivated by the agent. The hemolysins of this group can thus be inactivated by enzymatic attack on the prosthetic group, or by hydrolysis or deformation of the postulated carrier molecule.

EFFECTS OF PROTEIN, LIPIDS, AND SURFACTANTS ON THE ANTIMICROBIAL ACTIVITY OF SYNTHETIC STEROIDS

Three 4-azacholestanes and two A-norcholestanes were inactivated by 10 and 20% bovine serum and by 1.0, 2.5, and 5.0% sheep blood. The five compounds exhibited hemolytic properties when tested with 2% sheep blood and 2% human blood. These cholestanes inhibited Streptococcus pyogenes and were completely inactivated by 0.1% lecithin. Tween 80 was comparable to lecithin in causing the inactivation of steroids; 1% polyethylene glycol-4000 was inert; 1% Tween 20 and 1.0% Span 20 caused the inactivation of 3beta,4-dimethyl-4-aza-5alpha-cholestane (ND-307). The sodium salts of four fatty acids, oleate, stearate, deoxycholate, and lauryl sulfate (0.1 to 1.0 mg/ml), effectively interfered with the action of ND-307. The steroids appear to have some properties similar to those of antimicrobial surfactants of the cationic type but have certain distinct features.

ENZYMES INDUCED IN A BACTERIUM BY GROWTH ON SODIUM DODECYL SULFATE

Alkyl sulfatase was induced by growth on nutrient broth plus sodium dodecyl sulfate (SDS) in a bacterium we have designated Pseudomonas C12B. Measurement of the radioactivity of S(35)O(4) (=) released from SDS(35) by the enzyme in cell-free extracts provided an effective assay technique. The barium chloranilate assay for release of SO(4) (=) from SDS was somewhat less sensitive but effective if analyzed at 332 mmu. This test was only approximately 55% as sensitive if analyzed at 530 mmu. The activity of the glyoxylate bypass enzymes, isocitrate lyase and malate synthetase, was significantly stimulated by growth of the bacteria on SDS as the sole carbon source, but not by growth on nutrient broth or nutrient broth plus SDS.

STUDIES ON THE TISSUE ACTIVATOR OF PLASMINOGEN. DISTRIBUTION OF ACTIVATOR AND PROTEOLYTIC ACTIVITY IN THE SUBCELLULAR FRACTIONS OF RABBIT KIDNEY

1. On subcellular fractionation of rabbit kidney by differential and density-gradient centrifugation, a high proportion of the tissue activator of plasminogen activity was found to be particulate and displayed sedimentation properties associated with the lysosome-rich fraction as judged biochemically by the acid-phosphatase activity. 2. The activator activity is closely associated with a latent protease whose activity is enhanced in the presence of Triton X-100 or sodium deoxycholate in the neutral pH range. Besides hydrolysing casein this protease is also capable of attacking fibrinogen at pH7.4. 3. The pH optimum for activator activity and its inhibition by in-hexanoic acid (in-aminocaproic acid) point to its possible similarity to urokinase, an activator of plasminogen present in the urine of most mammals.