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.

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.

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.

The Influence of Hydrogen-ion Concentration on Some Acid Resistant Bacteria

1938 ◽  
Vol 4a (3) ◽  
pp. 219-227
Author(s):  
Dennis W. Watson
Keyword(s):  
Living Cell ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Resistant Bacteria ◽  
Limited Growth ◽  
Genus Bacillus ◽  
Hydrogen Ion Concentration ◽  
Ion Concentrations ◽  
Bacillus Strains

Fifty-three strains of bacteria have been isolated from acidulated brine. They are classified into Bacillus, Micrococcus, Sarcina, and Lactobacillus. Of these the Bacillus strains failed to grow at hydrogen-ion concentrations more acid than pH 6.20, while the Micrococcus and Sarcina forms showed a greater tolerance, producing limited growth from pH 5.22 to 5.64. Other workers describing wider limits for the genus Bacillus failed to allow for the change produced in the weakly buffered environment by the living cell. The microaerophilic Lactobacilli grew at pH 3.52. These aciduric types are not actively proteolytic.

PRODUCTION AND PROPERTIES OF 2,3-BUTANEDIOL: XXXII. 2,3-BUTANEDIOL FERMENTATIONS AT POISED HYDROGEN ION CONCENTRATIONS

1949 ◽  
Vol 27b (8) ◽  
pp. 694-704 ◽  
Author(s):  
A. C. Neish ◽  
G. A. Ledingham
Keyword(s):  
Bacillus Subtilis ◽  
Relative Yield ◽  
Ammonium Hydroxide ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Alkaline Media ◽  
Aerobacter Aerogenes ◽  
Hydrogen Ion Concentration ◽  
Ion Concentrations ◽  
Time Required

The anaerobic dissimilation of glucose by Bacillus polymyxa, Bacillus subtilis (Ford's type), Aerobacter aerogenes, and Serratia marcescens was studied at poised hydrogen ion concentrations covering the range pH 5.0 to 8.0. Each fermentation was controlled within ±0.05 pH units by automatic addition of ammonium hydroxide solutions. The hydrogen ion concentration had a marked effect on the overall rate of dissimilation and the relative yield of products that was similar for all organisms. The time required to completely ferment a medium containing 5% glucose varied from 22 hr. for Bacillus subtilis to [Formula: see text] for Aerobacter aerogenes at the optimum pH, which was within the range 7.0 to 7.6. The yield of 2,3-butanediol decreases above pH 6.4, until above pH 7.6 little or none is formed, although fairly rapid breakdown of glucose is still obtained. At the same time the yield of acetoin tends to increase, while there is little change in the amount of ethanol formed. The yields of acetic and lactic acids increase markedly in alkaline media, the latter showing an optimum at pH 7.6. A pronounced decrease in the yields of carbon dioxide and hydrogen occurs above pH 7.0 and is accompanied by an approximately equal increase in the yield of formic acid, which rises from 0.3 to 120 millimoles per 100 millimoles of glucose dissimilated in the A. aerogenes fermentation.

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