The action of air ions on bacteria. I. Protective and lethal effects on suspensions of Staphylococci in droplets.
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Techniques have been devised for studying quantitatively the effects of air ions on microorganisms suspended in small drops. In smog-contaminated atmospheres moderate concentrations of positive and negative air ions exerted a protective effect on staphylococci by delaying the drop in pH customarily observed and by diminishing the rate of evaporation. In clean air higher concentrations of positive and negative air ions accelerated the rate of death of staphylococci apparently by direct action on the cells and by increasing the rate of evaporation. Air ion action in these experiments did not involve cell agglutination or direct radiation from the radioactive isotopes employed. (+info)
Membrane-bound F1 ATPase from Micrococcus Sp. ATCC 398E. Purificationa and characterization ny affinity chromatography.
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A chemically reactive ATP analogue, 6-[(3-carboxy-4-nitrophenyl)thio]-9-beta-D-ribofuranosylpurine 5'-triphosphate (Nbs6ITP) has been synthesized. It has the ability to form stable thioether bonds between the 6-position of the purine ring and aliphatic mercapto groups. The nucleotide moiety of the reagent has been covalently bound to agarose, via iminobispropylamine and N-acetyl-homocysteine as space with the purpose of producing an affinity chromatography material. The affinity matrix binds solubilized F1 ATPase from a crude extract of Micrococcus sp. membranes. Afterwards the enzyme can be selectively eluted from the column at a defined ATP concentration. This method is superior to the conventional purification with respect to speed and convenince of the preparation. The affinity chromatography leads in a one-step process to the same purity to enzyme, substituting several steps of the conventional method. In addition, the affinity matrix was used for binding studies. Although the presence of Mg2+ ions is a prerequisite for the hydrolysis of nucleoside 5'-triphosphates, evidence is presented indicating that the binding of the nucleoside triphosphates to highly purified F1 ATPase from Micrococcus sp. appears not to be influenced by Mg2+ ion concentrations so far examined. (+info)
Antibiotic resistant staphylococci.
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An antibiotic resistant staphylococcus with bacteriophage pattern 52/42B/80/81* is frequently responsible for infectious outbreaks in the newborn nursery. Some time after an outbreak had occurred in the University of California's hospital nursery, family members of the infants were found to be infected with this strain. Two families were studied in detail. In one of them, infection developed in six of the seven members within eight months after the infant's arrival. In the other, half of the family members had recurrent infections during a 13-month period.Infants who left the nursery as asymptomatic carriers were found as likely to transmit the infectious strain as those with clinical infection. Considerable time sometimes elapsed before infection developed in either the infant or the family members. In one instance the first familial infection occurred six months after the infant had left the nursery as an asymptomatic carrier. Newborn infants are quite likely to disseminate antibiotic resistant staphylococci which they may acquire from a hospital nursery. Infections developing among persons in contact with a young infant must be treated with the possibility of a resistant hospital staphylococcus in mind. (+info)
Some pharmacological properties of the alpha-toxin of staphylococcus pyogenes.
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The alpha-toxin of Staphylococcus pyogenes produced a slowly developing contracture of isolated preparations of rabbit jejunum and of guinea-pig ileum which persisted after thorough washing and left the gut unresponsive to further doses of alpha-toxin or of acetylcholine. After incubation with antitoxin, the alpha-toxin no longer produced a contracture. Antitoxin only prevented the alpha-toxin response if added to the bath fluid before but not after the alpha-toxin. Certain drugs reduced the alpha-toxin contracture when added to the bath fluid before or after the alpha-toxin, but the contracture reappeared on washing. Papaverine abolished the contracture and pethidine was only slightly less active. Mepyramine, amyl nitrite, caffeine, aminophylline, adrenaline and ephedrine partly reduced the contracture. Hexamethonium, cocaine, tubocurarine and gallamine had no effect. The effect of atropine was only small. The gut-stimulant activity/haemolytic unit of two alpha-toxin samples differed greatly; this difference did not appear to be due to activity of impurities. The implications of these observations are discussed. (+info)
Intracellular survival of staphylococci.
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A tissue culture procedure is described which permits the quantitative evaluation of the intracellular survival of staphylococci within leucocytes. Staphylococcus aureus survived, but did not multiply, within neutrophils and monocytes of normal rabbits. The same was true of normal human blood leucocytes. Staphylococcus albus on the other hand was destroyed by these cells under the same conditions. Rat monocytes destroyed S. aureus and S. albus with equal facility. Although most experiments were carried out in the presence of 50 microg. streptomycin/ml., similar results were obtained without the use of this antibiotic. The applications of the tissue culture procedure with regard to studies on virulence and immunity in staphylococcal disease are discussed. (+info)
The effect of atebrin on bacterial membrane adenosine triphosphatases in relation to the divalent cation used as substrate and/or activator.
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The action of atebrin on purified adenosine triphosphatase (ATPase) from Micrococcus lysodeikticus was studied as well as on the membrane-bound and soluble ATPases from Escherichia coli and Bacillus megaterium. Atebrin inhibited the Ca(2+)-dependent activity of all these enzymes, and the inhibition was reversed by an excess of Ca(2+) ions. Kinetic studies carried out with the purified enzyme from M. lysodeikticus showed that the inhibition by atebrin was strongly cooperative, suggesting the complex nature of the process. On the other hand, atebrin stimulated the Mg(2+)ATPase activity of the M. lysodeikticus enzyme, displacing its adenosine 5'-triphosphate (ATP)/Mg(2+) optimum ratios, but inhibited the Mg(2+)-ATPase activity of E. coli provided that ATP was in excess over Mg(2+), i.e., that the ATP/Mg(2+) ratio was higher than its optimum. These results suggest that divalent cations influence the bacterial ATPases in different ways depending on the type of divalent ion and/or enzyme. The effect of atebrin on bacterial ATPases may reflect those differences, and its complex mechanism of action might be related to the existence of more than one site for divalent cations and/or distinct conformational states in these enzymes. (+info)
An extracellular material elaborated by Micrococcus sodonensis.
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Campbell, J. N. (American Meat Institute Foundation, Chicago, Ill.), James B. Evans Jerome J. Perry, and C. F. Niven, Jr. An extracellular material elaborated by Micrococcus sodonensis. J. Bacteriol. 82:828-837. 1961.-When actively growing in a yeast extract-tryptone broth, Micrococcus sodonensis produced rather large quantities of an extracellular material. On a dry weight basis, this material consisted of approximately 80% deoxyribonucleic acid (DNA), 6% ribonucleic acid, 13% protein, and a small quantity of a cell pigment which contained an associated iron porphyrinlike compound. The extracellular material was not produced in other complex or synthetic media. Removal of cells from the appropriate growth medium and suspension in distilled water resulted in the prevention of formation of the material if it had not already begun, or its immediate cessation in those cells which had been actively producing the material. Cells producing the extracellular material exhibited an increasingly higher concentration of intracellular DNA as incubation proceeded, whereas cells growing under conditions not supporting such production showed a decline in intracellular DNA as the culture aged. A similar increase of intracellular DNA, but not release of extracellular material, could be effected by addition of yeast extract or high levels of purine compounds to a medium which did not support the production of extracellular material. The base composition and ratios of both extracellular and intracellular DNA produced under all conditions tested were compared and found to be similar or identical, and to correspond to the classical Watson-Crick structure for DNA. (+info)
Effect of ammonium ion on growth and metabolism of Micrococcus sodonensis.
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Campbell, J. N. (American Meat Institute Foundation, Chicago, Ill.), James B. Evans, Jerome J. Perry, and C. F. Niven, Jr. Effect of ammonium ion on growth and metabolism of Micrococcus sodonensis. J. Bacteriol. 82:823-827. 1961.-When Micrococcus sodonensis was grown in a synthetic medium deficient in ammonia, large quantities of alpha-keto acids, chiefly alpha-ketoglutaric, accumulated in the medium. The addition of ammonium chloride to this medium prevented such accumulation and also supported increased growth, even in the presence of excess glutamate. Neither potassium nor sodium would substitute for ammonia in producing this effect. The results indicate that this microorganism has a specific requirement for the ammonium ion in its growth and metabolism. If not supplied exogenously, ammonia is made available by deamination of glutamic acid. The exact route of incorporation of ammonia is unknown. (+info)