scholarly journals THE MECHANISM OF COMPLEMENT ACTION

1920 ◽  
Vol 3 (2) ◽  
pp. 185-201
Author(s):  
S. C. Brooks
Keyword(s):  
Surface Tension ◽  
Serum Proteins ◽  
Ultra Violet ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Hydrogen Ion Concentration ◽  
Ion Concentrations ◽  
Ultra Violet Light ◽  
Violet Light ◽  
Molecular Group

It has been shown: 1. That complement exposed to ultra-violet light is not thereby sensitized to the action of heat (which indicates that it is not protein). 2. That inactivation of complement by ultra-violet light is accompanied by a decrease in its surface tension. 3. That photoinactivation of complement is not a result of any changes in hydrogen ion concentration since these are less than 0.05 pH. 4. That hydrogen ion concentrations high enough to transform serum proteins from the cation to the anion condition (i.e. past the isoelectric point) permanently inactivate complement. These facts together with those given in previous papers lead to the following hypotheses. 1. That there is present in serum a hemolytic substance which is formed from a precursor (which may resemble lecithin) and is constantly being formed and simultaneously being broken down into inactive products. 2. That both precursor and lysin contain the same photosensitive molecular group. 3. That the lytic substance is dependent for its activity upon the state of the serum proteins.

scholarly journals A STUDY OF THE BACTERICIDAL ACTION OF ULTRA VIOLET LIGHT

1929 ◽  
Vol 13 (2) ◽  
pp. 249-260 ◽  
Author(s):  
Frederick L. Gates
Keyword(s):  
Direct Action ◽  
Wave Length ◽  
Ultra Violet ◽  
Ion Concentration ◽  
Appreciable Effect ◽  
Bactericidal Action ◽  
Hydrogen Ion Concentration ◽  
Ultra Violet Light ◽  
Violet Light ◽  
Reciprocity Law

1. Wide differences in the intensity of incident ultra violet energy are not accurately compensated by corresponding changes in the exposure time, so that the Bunsen-Roscoe reciprocity law does not hold, strictly, especially for bactericidal action on young, metabolically and genetically active bacteria. In the present series of experiments, however, the energies used at various wave lengths did not differ by so much as to cause a significant error in the reported reactions. 2. The longer wave length limit of a direct bactericidal action on S. aureus was found to be between 302 and 313 mµ. The shorter limit was not determined because the long exposures required vitiate quantitative results. Bactericidal action was observed at λ225 mµ. 3. The temperature coefficient of the bactericidal reaction approaches 1 and thus furnishes empirical evidence that the direct action of ultra violet light on bacteria is essentially physical or photochemical in character. 4. The hydrogen ion concentration of the environment has no appreciable effect upon the bactericidal reaction between the limits of pH 4.5 and 7.5. At pH 9 and 10 evidence of a slight but definite increase in bacterial susceptibility was noted, but this difference may have been due to a less favorable environment for subsequent recovery and multiplication of injured organisms. 5. Plane polarization of incident ultra violet radiation has no demonstrable effect upon its bactericidal action. In a third paper of this group the ratios of incident to absorbed ultra violet energy at various wave lengths and the significance of these relations in an analysis of the bactericidal reaction will be discussed.

scholarly journals Precipitation Phenomena and the Wassermann Reaction

1926 ◽  
Vol 25 (4) ◽  
pp. 366-384 ◽  
Author(s):  
C. G. L. Wolf ◽  
E. K. Rideal
Keyword(s):  
Horse Serum ◽  
Ultra Violet ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Concentrated Solutions ◽  
Hydrogen Ion Concentration ◽  
Violet Light ◽  
Repeated Freezing ◽  
Precipitation Phenomena ◽  
Wassermann Reaction

1. “Antigens” of varying sensitivity may be prepared by coating a dispersion of gum benzoin with saponin.2. Using suitable dispersions so prepared a zone of precipitation is observed which is more extended for specific than for normal sera. Differentiation is more pronounced as the region of the isoelectric point of the globulin is approached.3. Precipitation is effected by the ions of salts present in the solution discharging the negative antigen suspension which has been sensitised by the protein of the serum.4. The mechanism of sensitisation is described.5. Both albumins and globulins can protect or sensitise gum benzoin suspensions, the effect depending on an appropriate dilution. This effect occurs qualitatively irrespective of the hydrogen ion concentration of the medium. Quantitatively the position of the zone of precipitation and its extent is contingent on the reaction of the medium.6. The euglobulin fractions of normal and of luetie sera deprived as far as possible of their lipoids can be differentiated both by the Wassermann test, and by precipitation tests.7. Delipoided euglobulins from horse serum will yield a Wassermann positive reaction when used in certain concentrations. In more concentrated solutions an anticomplementary effect is exhibited.8. Evidence is presented for the view that the euglobulins of specific sera differ rather in their composition or state of aggregation than in quantity from the euglobulin of non-specific sera.9. The changes in sensitising power and in the Wassermann reactivity of euglobulin caused by repeated freezing or exposure to ultra-violet light run a parallel course.10. Attempts to change the Wassermann properties of normal sera are briefly described.

VII.—A Study of the Fertilisation Membrane in the Echinoderms

1928 ◽  
Vol 47 ◽  
pp. 94-117 ◽  
Author(s):  
A. D. Hobson
Keyword(s):  
Surface Tension ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Essential Factor ◽  
Artificial Membrane ◽  
Asterias Rubens ◽  
Hydrogen Ion Concentration ◽  
Partial Activation ◽  
The Moment ◽  
Artificial Activation

Summary1. The view is confirmed that the zona pellucida is not an essential factor in the formation of the fertilisation membrane (pp. 96–100).2. Partial activation of the eggs of Asterias rubens is described with the formation of Seifriz's “protoplasmic papillæ” (pp. 100, 101).3. Artificial activation of the eggs of Asterias rubens by isotonic solutions of NaCl, KCl, CaCl2, and MgCl2 is described. It was found that decrease in surface tension is not a necessary factor in causing artificial membrane formation (pp. 102–104).4. The influence of the hydrogen ion concentration of the medium on the degree of extrusion of the fertilisation membrane of Echinus miliaris has been examined, and indicates that osmotic pressure due to the presence of a protein within the membrane is responsible for the extrusion (pp. 105–109).5. From a study of the influence of salt concentration on the extrusion of the fertilisation membrane of Echinus miliaris, it is concluded that the fertilisation membrane is, from the moment of its formation, completely permeable to salts (pp. 109–112).6. The origin of the fertilisation membrane has been examined, but in the absence of critical evidence it is concluded that the question cannot be regarded as settled (pp. 112–114).

scholarly journals THE RELATION OF THE PNEUMOCOCCUS TO HYDROGEN ION CONCENTRATION, ACID DEATH-POINT, AND DISSOLUTION OF THE ORGANISM

1919 ◽  
Vol 30 (4) ◽  
pp. 389-399 ◽  
Author(s):  
Frederick T. Lord ◽  
Robert N. Nye
Keyword(s):  
Hydrogen Ion ◽  
Ion Concentration ◽  
Direct Relation ◽  
Hydrogen Ion Concentration ◽  
Ion Concentrations ◽  
Cent Glucose ◽  
Fluid Media

1. In the growth and death of the pneumococcus in fluid media containing 1 per cent glucose the production of acid is the most important bactericidal factor. 2. 1 per cent glucose bouillon cultures of the pneumococcus allowed to grow and die out usually reach a final acidity of a pH of about 5.1. 3. At a hydrogen ion concentration of about 5.1 or higher, the pneumococcus does not survive longer than a few hours. 4. In hydrogen ion concentrations of about 6.8 to 7.4 the pneumococcus may live for at least many days. 5. In the intervening hydrogen ion concentrations, between 6.8 and 5.1, the pneumococcus is usually killed with a rapidity which bears a direct relation to the hydrogen ion concentration; i.e., the greater the acidity the more rapid is the death. 6. Cloudy suspensions of washed pneumococci in hydrogen ion concentrations varying from 8.0 to 4.0 show, after incubation, dissolution of organisms in lower hydrogen ion concentrations than about 5.0. This dissolution is most marked at about 5.0 to 6.0. Some dissolution also takes place toward the more alkaline end of the scale. No dissolution occurs at the most acid end of the scale.

scholarly journals THE RELATION OF PROTEOLYTIC ENZYMES IN THE PNEUMONIC LUNG TO HYDROGEN ION CONCENTRATION. AN EXPLANATION OF RESOLUTION

1919 ◽  
Vol 30 (4) ◽  
pp. 379-388 ◽  
Author(s):  
Frederick T. Lord
Keyword(s):  
Amino Acid ◽  
Proteolytic Enzyme ◽  
Gradual Increase ◽  
Cellular Material ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Acid Media ◽  
Hydrogen Ion Concentration ◽  
Ion Concentrations ◽  
Amino Acid Nitrogen

Evidence is given of the presence in the cellular material obtained from the pneumonic lung of a proteolytic enzyme digesting coagulated blood serum at hydrogen ion concentrations of 7.3 to 6.7 and inactive at higher; i.e., more acid concentrations. In addition, evidence is brought forward of the presence in the cellular material from the pneumonic lung of a proteolytic enzyme splitting peptone to amino-acid nitrogen. This enzyme is operative at hydrogen ion concentrations from 8.0 to 4.8, but most active at 6.3 or 5.2. These findings may be regarded as having a bearing on resolution in pneumonia. During the course of the disease a gradual increase in the hydrogen ion concentration of the exudate probably takes place. With the breaking down of cellular material an enzyme digesting protein (fibrin) in weakly alkaline and weakly acid media may be liberated. With a gradual increase in the hydrogen ion concentration of the pneumonic lung the action of this enzyme probably ceases. An enzyme capable of splitting peptone to amino-acid nitrogen is probably active during the proteolysis of the fibrin and further activated when the hydrogen ion concentration of the pneumonic lung is increased to within its range of optimum activity at a pH of 6.3 and 5.2. By this means it may be conceived that the exudate is dissolved and resolution takes place.

scholarly journals THE OPTIMUM HYDROGEN ION CONCENTRATION FOR THE GROWTH OF PNEUMOCOCCUS

1918 ◽  
Vol 28 (3) ◽  
pp. 345-357 ◽  
Author(s):  
K. G. Dernby ◽  
O. T. Avery
Keyword(s):  
Salt Concentration ◽  
Culture Media ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Initial Reaction ◽  
Hydrogen Ion Concentration ◽  
Ion Concentrations

1. The optimum hydrogen ion concentration for the growth of the various types of pneumococcus is a pH of about 7.8. 2. The limiting hydrogen ion concentrations for the growth of pneumococcus are a pH of 7.0 and a pH of 8.3. 3. Phosphates used in adjusting reactions of media retard growth if present in a concentration greater than 0.1 molecular. 4. Culture media for pneumococci should, therefore, have an initial reaction between a pH of 7.8 and 8.0 and a total salt concentration not exceeding 0.1 M.

scholarly journals The influence of hydrogen-ion concentration upon the adsorption of weak electrolytes by pure charcoal.—Part II

1931 ◽  
Vol 133 (821) ◽  
pp. 155-161 ◽  
Keyword(s):  
The Other ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Hydrogen Ion Concentration ◽  
Adsorption From Solutions ◽  
Ion Concentrations ◽  
Preferential Adsorption ◽  
Chemical Combination ◽  
Weak Electrolytes ◽  
Adsorption Curve

In a recent communication results were described which indicate that propionic, hexoic, and succinic acids are adsorbed by purified charcoal only as unionised molecules. There was no evidence that anions of these acids were adsorbed to any measurable extent. Thus the amount of these acids adsorbed from mixed solutions of any one acid and its sodium salt is propor­tional to the amount of unionised acid present as calculated from the known ionisation constants and the hydrogen-ion concentration of the solutions. Further work has led to the conclusion that the presence of an unionised carboxyl group is essential for adsorption to take place. On the other hand, the adsorption curve for the bases n -propylamine and n -butylamine at different hydrogen-ion concentrations did not follow the ionisation curves very closely.Strong preferential adsorption of the unionised molecule was observed but there was quite considerable adsorption from solutions of such acidity that no unionised amine could exist in them. The adsorption of both bases was found to fall off gradually and continuously with increasing acidity from p H 11 to P H 3. In view of the fact that the charcoal used in this work was Norit charcoal purified by treatment with strong halogen acids, it was thought possible that very small traces of these acids remained after the washing to which the char­coal was subjected, and that these traces of acid caused the adsorption of basic ions by direct chemical combination.

scholarly journals THE ISOELECTRIC POINTS OF THE PROTEINS IN CERTAIN VEGETABLE JUICES

1919 ◽  
Vol 2 (2) ◽  
pp. 145-160 ◽  
Author(s):  
Edwin J. Cohn ◽  
Joseph Gross ◽  
Omer C. Johnson
Keyword(s):  
Electric Field ◽  
Isoelectric Point ◽  
The State ◽  
Hydrogen Ion ◽  
Tomato Juice ◽  
Ion Concentration ◽  
Carrot Juice ◽  
Hydrogen Ion Concentration ◽  
Ion Concentrations ◽  
Isoelectric Points

The state in which a protein substance exists depends upon the nature of its combination with acids or bases and is changed by change in the protein compound. The nature of the compound of a protein that exists at any hydrogen ion concentration can be ascertained if the isoelectric point of the protein is known. Accordingly information regarding the isoelectric points of vegetable proteins is of importance for operations in which it may be desirable to change the state of protein substances, as in the dehydration of vegetables. The Protein in Potato Juice.—The hydrogen ion concentration of the filtered juice of the potato is in the neighborhood of 10–7N. Such juice contains the globulin tuberin to the extent of from 1 to 2 per cent. The character of the compound of tuberin that exists in nature was suggested by its anodic migration in an electric field. The addition of acid to potato juice dissociated this compound and liberated tuberin at its isoelectric point. The isoelectric point of tuberin coincided with a slightly lower hydrogen ion concentration than 10–4N. At that reaction it existed most nearly uncombined. The flow of current during cataphoresis was greatest in the neighborhood of the isoelectric point. This evidence supplements that of the direction of the migration of tuberin, since it also suggests the existence of the greatest number of uncombined ions near this point. At acidities greater than the isoelectric point tuberin combined with acid. The compound that was formed contained nearly three times as much acid as was needed to dissociate the tuberin compound that existed in nature. At such acidities tuberin migrated to the cathode. Though never completely precipitated tuberin was least soluble in the juice of the potato in the neighborhood of its isoelectric point. Both the compounds of tuberin with acids and with bases were more soluble in the juice than was uncombined tuberin. The nature of the slight precipitate that separated when potato juice was made slightly alkaline was not determined. The Protein in Carrot Juice.—The isoelectric point of the protein in carrot juice coincided with that of tuberin. Remarkably similar also were the properties of carrot juice and the juice of the potato. Existing in nature at nearly the same reaction they combined with acids and bases to nearly the same extent and showed minima in solubility at the same hydrogen ion concentrations. The greatest difference in behavior concerned the alkaline precipitate which, in the carrot, was nearly as great as the acid precipitate. The Protein in Tomato Juice.—The protein of the tomato existed in a precipitated form near its isoelectric point. Accordingly it was not present to any extent in filtered tomato juice. If, however, the considerable acidity at which the tomato exists was neutralized the protein dissolved and was filterable. It then migrated to the anode in an electric field. The addition of sufficient acid to make the hydrogen ion concentration slightly greater than 10–5N again precipitated the protein at its isoelectric point. At greater acidities migration was cathodic.

THE EFFECT OF TEMPERATURE AND pH ON THE LONGEVITY OF SCHISTOSOMATIUM DOUTHITTI MIRACIDIA

1962 ◽  
Vol 40 (4) ◽  
pp. 615-620 ◽  
Author(s):  
J. Farley
Keyword(s):  
Half Life ◽  
Large Population ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Effect Of Temperature ◽  
Critical Factors ◽  
Hydrogen Ion Concentration ◽  
Ion Concentrations ◽  
Constant Ph

Observations made on the effect of various temperatures and hydrogen ion concentrations on the longevity of Schistosomatium douthitti miracidia showed both to be critical factors. The half-life of the miracidia varied from 1.5 hours at 35 °C to 11 hours at 8 °C, at a constant pH of 7.3. The effect of hydrogen ion concentration was less pronounced, the optimum being pH 7.5. A large population of miracidia from a single liver continued hatching over a 4-hour period with a peak output occurring at half an hour and another at 1 hour after exposure to water. The longevity of the miracidia hatching within the first hour exceeded that of the larvae hatching later.

737. The heat coagulation of milk: II. variations in sensitivity of casein to calcium ions

1958 ◽  
Vol 25 (3) ◽  
pp. 467-474 ◽  
Author(s):  
G. T. Pyne
Keyword(s):  
High Temperature ◽  
Calcium Ions ◽  
Serum Proteins ◽  
Significant Part ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Temperature Stabilization ◽  
Phosphate Content ◽  
Hydrogen Ion Concentration ◽  
Phosphate Complex

1. The sensitivity to calcium of the caseinate-phosphate complex of milk heated at 120°C., increases to an early maximum and thereafter steadily declines, apparently in consequence of parallel changes in the sensitivity of its caseinate constituent.2. A simultaneously developed capacity of the heated complex to bind additional colloidal phosphate appears to be unrelated to these changes in casein sensitivity.3. Colloidal phosphate content is confirmed as a factor in the heat coagulation of milk.4. Heat-developed acidity contributes to the heat coagulation of milk primarily by increasing hydrogen-ion concentration and only slightly, if at all, through release of calcium ions from insoluble combinations.5. Neither serum proteins nor protein-lactose combinations play any significant part in the heat coagulation of milk.6. The bearing of these results on the heat coagulation of milk in general and on the operation of certain high-temperature stabilization treatments is discussed.

Sign in / Sign up

Export Citation Format

Share Document