scholarly journals A STABLE HEMOLYSIN-LEUCOCIDIN AND ITS CRYSTAL-LINE DERIVATIVE ISOLATED FROM BETA HEMOLYTIC STREPTOCOCCI

1938 ◽  
Vol 67 (4) ◽  
pp. 643-657 ◽  
Author(s):  
E. J. Czarnetzky ◽  
Isabel M. Morgan ◽  
Stuart Mudd
Keyword(s):  
Molecular Weight ◽  
Methylene Blue ◽  
Sodium Salt ◽  
Blood Cells ◽  
Chemical Structure ◽  
Free Acid ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Hydrogen Ion Concentration ◽  
High Degree

1. A chemically pure hemolysin-leucocidin has been isolated from ß hemolytic streptococci, but not from other species of bacteria studied. 2. It does not give rise to antibodies, but precipitates immune sera against hemolytic streptococci, and is therefore a hapten. 3. A highly purified sample of S. H. up to a dilution of 1:128,000 hemolyzes red blood cells. Its hemolytic activity is not specifically neutralized by antiserum versus ß hemolytic streptococci. It is leucocidic in that it inhibits the reduction of methylene blue by leucocytes. 4. The hemolysin-leucocidin is stable to oxygen, to heat and to moderate changes in hydrogen ion concentration. Its chemical structure has been determined in part. Its molecular weight is 2260. 5. A crystalline derivative has been isolated as the sodium salt from the hemolysin-leucocidin. As the free acid it has a molecular weight of 720. Its hemolytic and leucocidic activity parallels that of S. H., although it is not serologically active. It possesses a high degree of toxicity for mice and rabbits.

Iodine Compounds and Fertilisation

1931 ◽  
Vol 8 (2) ◽  
pp. 194-201
Author(s):  
G. S. CARTER
Keyword(s):  
Chemical Structure ◽  
Sea Water ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Hydrogen Ion Concentration ◽  
Chemical Substances ◽  
Iodine Compounds ◽  
Free Iodine ◽  
Length Of Life ◽  
A Current

1. The presence of thyroxine in a current of sea-water in which eggs of either E. esculentus or E. miliaris are being washed prolongs the fertilisable life of the eggs. 2. Under these conditions the fertilisable life of the eggs is of approximately the same length as that of eggs which are aerated in a small quantity of sea-water. 3. Des-iodo-thyroxine and free iodine also prolong the life of eggs, when they are present in the medium, but the prolongation produced by them is much less than that produced by thyroxine. No other of several chemical substances related to thyroxine produce this effect. Changes in the hydrogen-ion concentration of the medium between pH 7.2 and 9.4 have very little effect upon the length of life of the eggs. 4. It is concluded that the component of the secretions which is essential to the activation of the egg can be replaced by thyroxine, and is therefore the same as the component which produces effects similar to those of thyroxine on the oxygen consumption of the sperm. It is also concluded that it is probable that this substance, besides being similar to thyroxine in physiological action, is related to it in chemical structure.

scholarly journals DIFFERENTIATION OF HEMOLYTIC STREPTOCOCCI OF HUMAN AND OF DAIRY ORIGIN BY METHYLENE BLUE TOLERANCE AND FINAL ACIDITY

1929 ◽  
Vol 50 (4) ◽  
pp. 463-469 ◽  
Author(s):  
Roy C. Avery
Keyword(s):  
Methylene Blue ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Hydrogen Ion Concentration ◽  
Ph Range

A grouping of 138 strains of hemolytic streptococci based on differences in dye-sensitiveness and in final hydrogen-ion concentration of cultures is presented. Three groups are distinguished; (1) human parasitic strains, defined by a final pH range of 5.2 to 5.0 and by failure to reduce methylene blue (1:5000) in milk, (2) bovine strains parasitic in the udder, characterized by a final pH range of 4.5 to 4.2 and by failure to reduce methylene blue (1:5000) in milk, (3) saprophytic strains, characterized by a final pH range of 4.5 to 4.2 and by ability to reduce methylene blue. Methylene blue was bactericidal for the strains of hemolytic streptococci that fail to reduce it, but neither bacteriostatic nor bactericidal for the strains that caused its reduction.

Digestion in Parasitic Nematodes. III. The Digestion of Proteins

1941 ◽  
Vol 19 (1-2) ◽  
pp. 47-58 ◽  
Author(s):  
W. P. Rogers
Keyword(s):  
Free Acid ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Parasitic Nematodes ◽  
Similar Amount ◽  
Hydrogen Ion Concentration ◽  
Alkaline Side ◽  
Relative Production ◽  
Blood Albumin ◽  
Substrate Proteins

Tryptic-like enzymes have been extracted from the intestines and intestinal contents of Ascarts lumbricoides and Strongylus edentatus. The action of these enzymes, in relation to hydrogen ion concentration, has been examined.The parasite trypsins resembled pancreatic trypsin in that the relative production of “free acid” and “formaldehyde acid” was similar, but though acting only on the alkaline side of the isoelectric points of the substrate proteins, optimum action on gelatin, blood-albumin and casein was obtained at pH 6·2.The amount of protease extracted from a given weight of S. edentatus tissue was far greater than that from a similar amount of A. lumbricoides. Thus Strongylus digested 4·9 to 8·3 times as much gelatin, 12·5 to 40·9 times as much casein and 2·5 to 5·2 times as much blood-albumin as Ascaris.Spectroscopic examination of the process of digestion of oxyhaemoglobin showed, first, the formation of reduced haemoglobin and then the formation of haematin. These changes took place most rapidly at higher hydrogen ion concentrations.

scholarly journals THE EQUILIBRIUM BETWEEN HEMOLYTIC SENSITIZER AND RED BLOOD CELLS IN RELATION TO THE HYDROGEN ION CONCENTRATION

1921 ◽  
Vol 3 (4) ◽  
pp. 513-521 ◽  
Author(s):  
Calvin B. Coulter
Keyword(s):  
Red Blood Cells ◽  
Isoelectric Point ◽  
Blood Cells ◽  
De Novo ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Free Medium ◽  
Hydrogen Ion Concentration ◽  
Alkaline Side ◽  
Basic Dissociation

1. In a salt-free medium the proportion of the total amount of hemolytic sensitizer present, combined with the homologous cells, reaches a maximum of almost 100 per cent at pH 5.3. On the alkaline side of this point the proportion combined diminishes with the alkalinity and reaches a minimum of approximately 5 per cent at pH 10. On the acid side of pH 5.3 the proportion combined diminishes with the acidity but somewhat less rapidly than for a corresponding increase in alkalinity. 2. The presence of NaCl greatly increases the proportion of sensitizer combined with cells at all reactions except those in the neighborhood of pH 5.3. At this point the combination of sensitizer with cells is independent of the presence of electrolyte. 3. The curves representing the proportion of sensitizer combined or free run almost exactly parallel, both when the sensitizer combines de novo and when it dissociates from combination; therefore, in constant volume, at a given hydrogen ion concentration, and at a given temperature, an equilibrium exists between the amount of sensitizer free and that combined with cells. 4. The combination of sensitizer and cells is related fundamentally to the isoelectric point of the sensitizer. 5. The dissociated ions of the sensitizer, formed either by its acid or its basic dissociation, do not unite with cells. Combination takes place only between the cells and the undissociated molecules of the sensitizer.

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