scholarly journals INFLUENCE OF TEMPERATURE AND HYDROGEN ION CONCENTRATION UPON THE SPORE CYCLE OF BACILLUS SUBTILIS

1919 ◽  
Vol 1 (4) ◽  
pp. 421-428 ◽  
Author(s):  
Arao Itano ◽  
James Neill
Keyword(s):  
Ph Value ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Practical Application ◽  
Vegetative Cells ◽  
Hydrogen Ion Concentration ◽  
Influence Of Temperature ◽  
Ph Values ◽  
Metabolic Products ◽  
Slight Growth

1. At 5°C. no germination took place. 2. At 25°C. and at 37°C. germination occurs if the hydrogen ion concentration of the broth is kept between pH 5 and pH 10, but not at higher or lower pH values. 3. The completion of the spore cycle likewise requires a hydrogen ion concentration between pH 5 and pH 10. 4. The spores can germinate when the pH value is 10, although after germination the vegetative cells multiply only to a very slight extent and soon pass into spores. 5. The slight growth and multiplication of vegetative cells in broth of pH 10 suggest that the formation of endospores in this medium must be caused largely by the unfavorable reaction of the medium rather than by the accumulation of metabolic products. 6. Automatic adjustment of the medium seems to play a rôle in the completion of the spore cycle. 7. The results are not only of theoretical importance but they have a practical application to the preservation of food by canning and by other methods.

Phosphate transport in the proximal convoluted tubule: effect of intraluminal pH

1984 ◽  
Vol 246 (3) ◽  
pp. F323-F333 ◽  
Author(s):  
G. A. Quamme ◽  
N. L. Wong
Keyword(s):  
Parathyroid Hormone ◽  
Ph Value ◽  
Phosphate Transport ◽  
Phosphate Concentration ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Plasma Phosphate ◽  
Hydrogen Ion Concentration ◽  
Phosphate Absorption ◽  
Ph Values

The effect of intraluminal hydrogen ion concentration on phosphate absorption was evaluated in the rat superficial proximal tubule. Early proximal convoluted tubules were perfused in vivo with buffered equilibrium solutions, and the saturation kinetics for phosphate transport was determined by altering intraluminal phosphate concentration at pH values of 7.65 and 6.5. The apparent Jmax and Km parameters of phosphate transport were about twofold greater with intraluminal pH 7.65 compared with pH 6.5 values. Accordingly, intraluminal hydrogen ion had a direct effect on tubular phosphate transport. Endogenous or exogenously administered parathyroid hormone inhibited phosphate absorption at both pH values, indicating that the phosphaturic action of parathyroid hormone is independent of the intraluminal pH value. Elevation of plasma phosphate inhibited phosphate absorption unrelated to the intraluminal phosphate concentration at both pH values. These data suggest that elevation of plasma phosphate may decrease phosphate absorption by inhibiting efflux from the cell into the peritubular capillary. In conclusion, proximal phosphate absorption is determined by the intraluminal pH value, circulating parathyroid hormone level, and plasma phosphate concentration acting through separate cellular and membrane mechanisms.

THE ELECTRODE POTENTIAL OF IRON IN RELATION TO HYDROGEN ION CONCENTRATION

1936 ◽  
Vol 14b (1) ◽  
pp. 31-40 ◽  
Author(s):  
J. W. Shipley ◽  
J. H. Shipley
Keyword(s):  
Electrode Potential ◽  
Chloride Ion ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Iron Electrode ◽  
General Corrosion ◽  
Citrate Buffer ◽  
Hydrogen Ion Concentration ◽  
Electrically Conducting ◽  
Ph Values

The electrode potential of iron immersed in phosphate, borate and citrate buffers of varying hydrogen ion concentration was measured, using a normal calomel electrode as the second half of the cell. Breaks in the potential of the iron electrode amounting to as much as 0.7 volts were found to occur at definite pH values for each series of buffers. The electrode exhibited an "initial" and "final" potential depending on the pH of the electrolyte and the time of immersion, the "final" value requiring several days to become established. The "final" break in the electrode potential of 0.74 volts in the pure phosphate buffer occurred between a pH of 3.1 and 4.0, that in the pure borate buffer, of 0.75 volts, occurred between a pH of 4.3 and 4.6, and in the pure citrate buffer, of 0.77 volts, between a pH of 10.1 and 10.9. The effect of chloride ion and de-aeration on the electrode potential was observed. It is suggested that the potential of the iron electrode is determined by the presence or absence of a non electrically conducting film or deposit on the iron, the formation of which is a function of the nature of the electrolyte and its hydrogen ion concentration. De-aeration apparently had no effect on the electrode potential, but the presence of chloride ion affected the establishing of the "final" potential and caused the break in voltage to appear irregularly at a much lower hydrogen ion concentration.At pH values below that at which the break in potential occurred, corrosion of the iron electrode was marked, and the electrode potential remained high, while, at pH values above the break, corrosion was virtually inhibited or confined to local spots on the electrode, and the electrode potential remained low. The presence of the chloride ion stimulated local corrosion and permitted general corrosion to proceed at a lower hydrogen ion concentration.

scholarly journals THE EFFECT OF THE H ION CONCENTRATION ON THE AVAILABILITY OF IRON FOR CHLORELLA SP

1925 ◽  
Vol 9 (2) ◽  
pp. 205-210 ◽  
Author(s):  
E. F. Hopkins ◽  
F. B. Wann
Keyword(s):  
Ph Value ◽  
Maximum Growth ◽  
Chemical Precipitation ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Alkaline Solutions ◽  
Culture Solution ◽  
Hydrogen Ion Concentration ◽  
Chlorella Sp ◽  
Nutrient Solutions

The data obtained in these experiments indicate clearly that unless the necessary precautions are taken to keep the iron of the culture medium in solution the results obtained by varying the H ion concentration will not represent the true effect of this factor on growth. The availability of iron in nutrient solutions has been the subject of numerous recent investigations and it is now known that iron is precipitated at the lower hydrogen ion concentrations, that the iron of certain iron salts is less likely to be precipitated than that of others, and that certain salts of organic acids tend to keep the iron in solution. In general, ferric citrate seems to be the most favorable source of iron. In addition to chemical precipitation, however, it is also possible for the iron to be removed by adsorption on an amorphous precipitate such as calcium phosphate. As this precipitate is frequently formed when nutrient solutions are made alkaline, this may account for the discordant results reported in the literature as to the availability of certain forms of iron. By omitting calcium from the culture solution iron can be maintained in a form available for growth in alkaline solutions by the addition of sodium citrate. In such solutions the maximum growth of Chlorella occurred at pH 7.5. The alkaline limit for growth has not been established as yet. In investigating the availability of iron at varying concentrations of the hydrogen ion, changes in the pH value of the solution during the course of an experiment should also be taken into account. This is especially important in unbuffered solutions. The differential absorption of the ions of ammonium salts may cause a marked increase in the hydrogen ion concentration, which in turn will cause an increase in the solubility of iron. In strongly buffered solutions as used in these experiments this effect is slight.

scholarly journals THE USE OF THE FINAL HYDROGEN ION CONCENTRATION IN DIFFERENTIATION OF STREPTOCOCCUS HÆMOLYTICUS OF HUMAN AND BOVINE TYPES

1919 ◽  
Vol 29 (2) ◽  
pp. 215-234 ◽  
Author(s):  
Oswald T. Avery ◽  
Glenn E. Cullen
Keyword(s):  
Hydrogen Ion ◽  
Ion Concentration ◽  
Human Origin ◽  
Practical Application ◽  
Cream Cheese ◽  
Hydrogen Ion Concentration ◽  
Human Type

1. Under the conditions of these experiments, there appears to be a distinct and constant difference in the final hydrogen ion concentration of Streptococcus hæmolyticus from human and bovine sources. 2. Of 124 strains of Streptococcus hæmolyticus from known human origin, 116 reached a final hydrogen ion concentration of from pH 5.0 to 5.3. Only 8 reached a pH more acid than 5.0 and none more acid than pH 4.8. 3. Of 45 strains of Streptococcus hæmolyticus from bovine sources, including 26 strains isolated from milk and the udder of cows, and 19 from cream cheese, 40 reached a final hydrogen ion concentration of pH 4.3 to 4.5. Of the remaining 5 which reached a pH of 5.0 to 5.2, two were of known human type and three of uncertain diagnosis. 4. A rapid and practical application of this method is proposed as a presumptive test in the differentiation of human and bovine types of Streptococcus hæmolyticus.

scholarly journals The Hydrogen Ion Concentration of the Cells of some Marine Algæ

1922 ◽  
Vol 12 (4) ◽  
pp. 785-788 ◽  
Author(s):  
W. R. G. Atkins
Keyword(s):  
Marine Algae ◽  
Plant Cells ◽  
Hydrogen Ion ◽  
Land Plants ◽  
Ion Concentration ◽  
Hydrogen Ion Concentration ◽  
Ph Values ◽  
Optimum Ph ◽  
Acid Character

The measurements recorded for marine algæ of various groups show that the reaction of the sap is in most cases almost neutral, and in no case is the sap of the pronounced acid character met with in many land plants. This being so it follows that the enzymes concerned in the metabolism of these algæ must be quite different from those which effect corresponding changes in land plants, as may be seen on referring to the optimum pH values for various enzymes quoted in the writer's previous paper on the reaction of plant cells (1922).

scholarly journals THE COMPOSITION OF THE CELL SAP OF THE PLANT IN RELATION TO THE ABSORPTION OF IONS

1923 ◽  
Vol 5 (5) ◽  
pp. 629-646 ◽  
Author(s):  
D. R. Hoagland ◽  
A. R. Davis ◽  
Keyword(s):  
Cell Wall ◽  
Higher Plants ◽  
Ph Value ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Inorganic Elements ◽  
Dilute Solutions ◽  
Chemical Examination ◽  
Hydrogen Ion Concentration ◽  
Insoluble Form

1. Chemical examination of the cell sap of Nitella showed that the concentrations of all the principal inorganic elements, K, SO4, Ca, Mg, PO4, Cl, and Na, were very much higher than in the water in which the plants were growing. 2. Conductivity measurements and other considerations lead to the conclusion that all or nearly all of the inorganic elements present in the cell sap exist in ionic state. 3. The insoluble or combined elements found in the cell wall or protoplasm included Ca, Mg, S, Si, Fe, and Al. No potassium was present in insoluble form. Calcium was predominant. 4. The hydrogen ion concentration of healthy cells was found to be approximately constant, at pH 5.2. This value was not changed even when the outside solution varied from pH 5.0 to 9.0. 5. The penetration of NO3 ion into the cell sap from dilute solutions was definitely influenced by the hydrogen ion concentration of the solution. Penetration was much more rapid from a slightly acid solution than from an alkaline one. It is possible that the NO3 forms a combination with some constituent of the cell wall or of the protoplasm. 6. The exosmosis of chlorine from Nitella cells was found to be a delicate test for injury or altered permeability. 7. Dilute solutions of ammonium salts caused the reaction of the cell sap to increase its pH value. This change was accompanied by injury and exosmosis of chlorine. 8. Apparently the penetration of ions into the cell may take place from a solution of low concentration into a solution of higher concentration. 9. Various comparisons with higher plants are drawn, with reference to buffer systems, solubility of potassium, removal of nitrate from solution, etc.

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