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.

HISTOCHEMICAL DEMONSTRATION OF MUSCLE LIPASE

A method which is an advance over the existing methods for the histochemical demonstration of lipase activity in muscle, using "Tween 85' as substrate and alizarin red S as stain for the calcium soap formed, is described. Lipase has been localized in the mitochondria of the fish trunk and pigeon breast muscles.

FURTHER STUDIES ON A LABILE IMMUNOGENIC PARTICULATE SUBSTANCE ISOLATED FROM MYCOBACTERIUM TUBERCULOSIS

Youmans, Anne S. (Northwestern University Medical School, Chicago, Ill.), and Guy P. Youmans. Further studies on a labile immunogenic particulate substance isolated from Mycobacterium tuberculosis. J. Bacteriol. 87:278-285. 1964.-A particulate fraction which was highly immunogenic for mice was collected by ultracentrifugation from mycobacteria disrupted in 0.25 m sucrose buffer. The active immunogenic material was present in the gelatinous pellet obtained after centrifugation at 40,000 rev/min (144,000 x g) for 3 hr. This active material could be prepared free from whole cells and cell walls. This was done either by several centrifugations at lower speeds, or by filtering the supernatant fluid from the 10,000 rev/min centrifugation through a Millipore filter (porosity 0.5 mu). No microorganisms were found on slides or in cultures made from these filtrates. The immunogenic moiety in the particulate fraction was found to be very labile. Temperatures higher than 0 to 4 C inactivated the immunogenic activity. There was an irreversible linear decrease in activity as the temperature increased. If fractions were frozen or lyophilized, the activity remained as high as the original material for 4 weeks, and then rapidly decreased. The immunogenic material also was very sensitive to the hydrogen-ion concentration; the optimal activity was found at pH 6.8 to 7.0. The activity decreased rapidly at more acid or alkaline pH values. Also, particulate fraction prepared in sucrose buffer at pH 7.3 and 7.6 was much less active than that prepared in sucrose buffer at pH 7.0. Immunogenic activity was decreased if the particulate fraction was dialyzed overnight against 0.01 m phosphate buffer or distilled water at 4 C. The detergent sodium lauryl sulfate inactivated immunogenic activity. Moreover, the use of a Waring Blendor to blend the ruptured cell mass before centrifugation decreased the activity. Finally, a markedly lower activity resulted if both the 20,000 and 40,000 rev/min centrifugations were done the day after the rupture of the cells. Some refinements in technique which are used now in the preparation of the particulate fraction are detailed.

DEOXYRIBONUCLEIC ACID BASE COMPOSITION OF SOME MEMBERS OF THE SUBGENERA BETABACTERIUM AND STREPTOBACTERIUM

The base composition of deoxyribonucleic acid (DNA) prepared from four Betabacterium strains and four Streptobacterium strains was determined. Per cent GC values (guanine + cytosine/total bases) of the DNA were evaluated from the "melting-temperatures" (Tm) of the nucleic acids. For the Betabacterium strains, these values ranged from 44 to 51.5% GC, and those for the Streptobacterium strains ranged from 43 to 47.5% GC. The taxonomic division into these two subgenera is not, therefore, supported by these findings.

GUANINE-DEAMINASE ACTIVITY IN RAT BRAIN AND LIVER

1. Guanine deaminase in rat brain and liver was distributed among all the subcellular fractions: nuclei, ;heavy' mitochondria, ;light' mitochondria, microsomes and the supernatant fluid. The greater part of the activity passed into the soluble fraction. Among the particulate components, the ;light' mitochondria constituted the richest fraction. 2. The sum of the enzymic activities of the component fractions obtained on differential centrifugation was considerably greater than the activity of guanine deaminase in the whole homogenate. 3. The ;heavy'-mitochondrial fraction had a powerful inhibitory effect on the guanine-deaminase activity of the supernatant fraction. 4. All the sedimented fractions, except the microsomes, gave rise to higher guanine-deaminase activity on treatment with Triton X-100. 5. The inhibitory capacity of the ;heavy' mitochondria increased on treatment with Triton X-100; the detergent-treated nuclear fraction also brought about inhibition of the 5000g supernatant. 6. Guanine-deaminase inhibitor from the ;heavy' mitochondria was solubilized by high-speed grinding of the particles, followed by treatment with Triton X-100. The inhibitor appeared to be protein in nature, since it was precipitated by trichloroacetic acid and by half-saturation with ammonium sulphate, and was non-diffusible. It was inactivated by heating at 50 degrees for 5min. 7. It is possible that the guanine deaminase associated with particles differs from the soluble enzyme in its response to inhibitor.

A RESPIROMETER TECHNIQUE FOR ESTIMATING GERMICIDAL ACTIVITY ON SKIN

1. A technique for measuring the antibacterial activity of germicides on pig skin in micro-respirometers has been described.

2. Using this technique the activity of the following germicides has been estimated: 2,2-dihydroxy, 3,5,6,3′,5′,6′-hexachlorodiphenylmethane, 3,4,4′-trichlorocarbanilide, 3,5,4′tribromosalicylanilide, 2,2′-thiobis (4,6-dichlorophenol), Irgasan CF3*, 3,5,3′,4′-tetrachlorosalicylanilide.

3. The results obtained have been discussed in relation to hand-washing test results (Hurstet al.1960).

CONVULSIVE SYNDROME IN RABBITS INJECTED WITH FAT EMULSION AND HEPARIN

Functionally hepatectomized rabbits showed convulsions and coma within 2 hours after the intravenous injection of fat emulsion and heparin. Intravenous injection of the detergent triton prevented this syndrome, if given before the fat emulsion and heparin, and reversed it if given subsequently. Extremely high plasma non-esterified fatty acid levels were noted in rabbits showing the convulsive syndrome, but not in animals that received the detergent. The mechanism of the convulsions probably includes the toxicity of high amounts of non-esterified fatty acids.