High Hydrogen Ion Concentration Research Articles

CHEMICAL PROPERTIES OF THE PURIFIED SPREADING FACTOR FROM TESTICLE

1. The factor responsible for the spreading property of testicle extracts was found to be soluble in water, in salt solution, and in acid media. It is relatively stable at high hydrogen ion concentrations, and it is not precipitated or inactivated by hydrochloric acid up to pH 2.0. The spreading substance is not soluble in acetone, ether, alcohol, chloroform, or pyridine. It is inactivated by crystalline trypsin and pepsin at the optimum pH of action of these enzymes. It is not attacked by a crystallized carboxypolypeptidase. The substance does not pass semipermeable membranes which retain proteins. The color tests for proteins are positive. At least 14.2 per cent of the fraction isolated is nitrogen. Taken together these properties are strong evidence that the testicular factor is a protein. 2. A method for the preparation of the spreading factor in relatively pure form is presented and discussed. 3. In addition to the spread, concentrated solutions of the testicular factor are shown to produce a condition of the skin having the characters of edema.

THE POTASSIUM EQUILIBRIUM IN MUSCLE

1. Analyses were made of the K and HCO(3) content, the irritability, and weight change of isolated frog sartorius muscles after immersion for 5 hours in Ringer's solutions modified as to pH and potassium content. 2. At each pH a concentration of potassium in the solution was found which was in diffusion equilibrium with the potassium in the muscle. In greater concentrations potassium moved into the muscle against the concentration gradient and vice versa. 3. The greater the alkalinity of the solution the smaller the concentration of the potassium at equilibrium so that the product of the concentrations of OH and K in the solution at equilibrium tends to remain approximately constant. 4. The pH inside the muscle is approximately equal to that outside when first dissected but it tends to change during immersion so as to follow the changes in the pH of the solution. This finding is in direct conflict with the theory according to which the high potassium concentration inside should be accompanied by an equally high hydrogen ion concentration in relation to that outside. 5. The diffusion of potassium into the muscle makes its contents more alkaline but the increase in alkalinity is not always, nor usually, equivalent to the amount of potassium which has diffused and conversely, the pH inside can change in either direction according to the pH outside without there being any diffusion of potassium. Hence potassium is not the only penetrating ion. 6. The irritability of the muscles is at a maximum in concentrations of potassium which are greater than that in normal Ringer's solution, or about 20 mg. per cent potassium. This optimum does not seem to be a function of pH and is therefore not dependent upon the direction of movement of the potassium but probably on the ratio of potassium outside to that inside. 7. Swelling of the muscles occurs in solutions which injure the muscle so as to permit both cations and anions to enter without permitting the organic protein anions to escape. Anion impermeability is necessary to prevent this same osmotic swelling under normal conditions. 8. An increase in the CO(2) tension in muscle and solution causes a greater increase in acidity in the solution than in the muscle and leads to a loss of potassium. One expects therefore a potassium shift from tissues to blood comparable to the chlorine shift from plasma to corpuscles.

OBSERVATIONS ON HYDRA AND PELMATOHYDRA UNDER DETERMINED HYDROGEN ION CONCENTRATION

1. The optimum range of hydrogen ion concentration for both Hydra viridissima and Pelmatohydra oligactis lies within the range pH 7.8 and 8.0.2. Polyps allowed to develop pronounced dedifferentiation and resorption in a high hydrogen ion concentration (low pH) were induced to completely restore their lost parts when the medium was altered to be within the optimum range of pH.3. Hydras carried within the optimum range of pH were subjected to periods of inanition as great as twenty five days without showing any external evidence of dedifferentiation and resorption at the end of this period.4. Histological preparation of polyps, kept for long periods without food at the optimum hydrogen ion concentration, show slight evidence histologically of dedifferentiation and resorption at a critical period. This critical period appears somewhere between ten and seventeen days after inanition within the optimum range of pH. Such microscopic dedifferentiation and resorption are not progressive; for after this critical period has passed no further histological evidence of dedifferentiation and resorption has been observed.(b) This microscopic dedifferentiation and resorption usually appear at the tips of the tentacles; but in one case we have seen it involve the basal third of the polyp and not the tentacles.5. Hydras subjected to long periods of inanition within the optimum range of pH accept food readily. There is, therefore, no evidence of depression given by these polyps.6. Dedifferentiation and resorption are induced rather by unfavorable hydrogen ion concentration than by inanition.

On the Wave-like Variation of the Contraction Height of the Skeletal Muscle on Introducing Short Periods of Rest in its Contraction Series

In the contraction series of the frog's gastrocnemius muscle, exposed to the air or immersed in Ringer's solution, mostly at the room temperature of 22° to 26°C., and directly stimulated 30 times per minute with maximal induction shocks, short periods of rest were introduced and the form of both the summit and base lines were observed. In general, when a contraction series was separated in groups of 30 contractions by introducing every minute a rest of 10 see., there appeared after each rest wave-like variations of the summit line in the middle part of the fatigue curve, i. e. after the finishing of the initial increase (treppe), and with beginning of the decrease of contraction height, but never in the initial and only seldom in the terminal stage. This phenomenon was most striking in the gastrocnemius of a summer frog (Rana nigromaculata). The wave-rate was 2 or 3 per minute, diminishing with the advance of fatigue. The oscillations having once appeared continued, if no further interruption by rest was made, some 2 minutes, and gradually disappeared. But as there were seen many other variation forms, evoked by introducing rest, four types of variation were distinguished. The form of the base line itself and also in relation to the summit line form was rather irregular. It was to be seen that the rise of the base line (contracture), sometimes oscillatory, occurred mostly in those fatigue curves which showed wave-like oscillations of the summit line, and not in those without these, but there were many exceptional cases. The base line rise is not the essential or coexisting condition for the production of summit line waves. The variation form, the wave-time, the time of appearing and disappearing and the time duration of waves, these all depend on several influences, among which those of the difference of individual animals, the difference of muscles, the temperature, the loading, and the stimulation rate are the most remarkable. The wave-time showed no remarkable dependence on the rate of stimulation to the extent of from 15 to 60 per minute. It decreased with the decrease of the duration of contraction, especially such as in the rise of temperature, the temperature coefficient Q10 being about 1.6. The temperature of 22°-26C. was the most favourable for the appearance of the wave-like oscillation. A high temperature above 30°C. and often also a high stimulation rate above 60 per minute were unfavourable for it. On the whole, conditions which act to hasten fatigue, such as a shorter rest time, a heavier load, a higher stimulation rate, an increase of the intensity of stimulus, a higher hydrogen-ion concentration etc. act also to hasten both onset and cessation of the waves of the summit line, and vice versa. But in many of these, the influenee was an inconsiderable one and nothing but a slight trace was to be observed. No evidence could be brought as to the facillating action of adrenaline or of hydrogen-ion (lactic acid) for the production of oscillatory variation of contraction height on introducing short periods of rest.

Comparative buffering value of American peptones

Some time ago one of us reported before this Society the results of the inquiry into the effect of the composition of the medium as affecting the reliability of the cultural methods of identification of bacteria, and has particularly insisted on the rôle of the buffer and on necessity of quantitative adjustment of media in respect to its buffer content. In the present investigation we have attempted to determine the buffer content of a few of the commercial peptones with the view of determining the limits of possible variation in the buffer content in the media prepared in different laboratories as due to the choice of peptone alone. The method used was that of determining electrometrically the hydrogen ion concentration of the various peptone solutions before and after the addition to them of measured amounts of acid and alkali respectively. The study demonstrated the fact that initial reaction of different peptones varies within fairly broad limits, that due to complexity of composition the buffering action of any given peptone varies at different zones of hydrogen ion concentration, and that buffering action of one peptone at a given hydrogen ion concentration may exhibit as much as five times more buffering action than another peptone at the same hydrogen ion concentration. In general, the peptones tested showed the highest degree of variation in buffering effect in the zone of the hydrogen ion concentration limited between PH = 9 and PH = 8, and the lowest degree of variation in the zone between PH = 4 and PH = 5. As to the absolute concentration of buffering salts, these were found in most peptones to be the highest at the zone of the lowest concentration of the hydrogen ions and not in the zone of neutrality or of high hydrogen ion concentration where the buffering action would be most desirable for the use in media for identification of bacteria. Below is a table showing the relative buffering action of peptones at various PH levels.

STUDIES IN THE PHYSIOLOGY OF SPERMATOZOA

STUDIES IN THE PHYSIOLOGY OF SPERMATOZOA