Specific Ion Concentrations Research Articles

Factors affecting the movement of slime mold plasmodia

1. 1. Migration rate of oriented plasmodia of Physarum polycephalum is determined by environmental parameters of substratum osmolarity, pH. temperature, and specific ion concentrations. 2. 2. Migration occurred between substratum osmolarities of 0–340 mOsmoles, pH values of 2.35—12.0, and temperatures of 8–37°C (optimum for our experimental conditions, 24°C). 3. 3. Except for rubidium, common metallic cations depressed migration rate over and above their concentration effect, as follows in decreasing order of effectiveness: Mg 2+, Ca 2+, Li +, Na +, K +, Rb +. 4. 4. Data obtained in these experiments are interpreted to demonstrate that the sol-gel equilibrium of the plasmodium is the major determinant of migration rate.

Oxygen equilibria of the vascular and coelomic hemoglobins of the terebellid polychaete, Pista pacifica. Evidence for an oxygen transfer system

1. 1. The oxygen equilibria of vascular and coelomic hemoglobins of the terebellid polychaete, Pista pacifica, have been investigated. 2. 2. The effects of hemoglobin concentration, temperature, pH and concentration of specific ions on the oxygen affinity and shape of the dissociation curves have been studied. 3. 3. Under all conditions examined, the coelomic cell hemoglobins have a higher oxygen affinity than the vascular hemoglobin, suggesting an oxygen transfer system from the branchial gills to the vascular hemoglobin and then to the coelomic cell hemoglobins. 4. 4. The oxygen equilibrium properties of these pigments are compared with those of other hemoglobins under similar conditions.

IONIC EFFECTS ON LIGNIFICATION AND PEROXIDASE IN TISSUE CULTURES

Crown-gall tumor tissue cultures release peroxidase into the medium in response to the concentration of specific ions in the medium. This release is not due to diffusion from cut surfaces or injured cells. Calcium, magnesium, and ammonium were, in that order, most effective in increasing peroxidase release. The enzyme was demonstrated cytochemically on the cell walls and in the cytoplasm. Cell wall fractions, exhaustively washed in buffer, still contained bound peroxidase. This bound peroxidase could be released by treating the wall fractions with certain divalent cations or ammonium. The order of effectiveness for removing the enzyme from the washed cell walls is: Ca(++) approximately Sr(++) > Ba(++) > Mg(++) > NH(4) (+). These data support the thesis presented that specific ions can control the deposition of lignin on cell walls by affecting the peroxidase levels on these walls.

FACTORS AFFECTING HEMAGGLUTINATION BY ENTEROVIRUSES.

Discussion and summarySome of the factors that are known to affect the agglutination of various erythrocytes by viruses are the age of the donor animal, the hydrogen ion concentration of the diluent and the temperatures at which erythrocytes are allowed to sediment. The results reported here indicate that these factors, either singly or in combination, also affect the agglutination of human erythrocytes by enteroviruses known to possess this property.Cord erythrocytes or diluents of specific hydrogen ion concentration are not usually necessary for demonstration of enterovirus hemagglutinins. However, the use of these cells and of diluents other than those buffered at or above pH 7.0 has enabled us to detect hemagglutinating activity where it existed in what might be termed a “borderline state.” This was exemplified by our demonstration of hemagglutination by ECHO virus type 24. Other reports(15,29,30) have indicated that the pH optimum for hemagglutination reactions with certain enteroviruses was other th...

TRACE METAL CONTROL OF BACTERIAL FLAGELLATION.

SPECIFIC alterations in the normal battery of biosynthetic processes often occur when moderate changes are made in the balance of metallic ions in the environment. In microbial systems, for example, the quantities synthesized of organic acids, porphyrins, vitamins, antibiotics, toxins, enzymes, lipids, and polysaccharides are controlled by precise balances of metallic ions that permit, but are not necessarily optimal for, vegetative growth. Likewise, the execution of such physiological processes as cell division; sporulation; germination; plasmodia and vesicle formation; and adsorption, induction, and synthesis of bacterial viruses depends on concentrations of specific metallic ions that differ from the minimum quantities needed for synthesis of protoplasm. Indeed, the tolerance of normal vegetative growth to fluctuation of the metallic ion environment is considerably greater than the fluctuation tolerated by a specific biosynthetic or physiological process1.

The influence of ultrasonic waves on selenium hydrosol

The influence of ultrasonic waves on selenium hydrosol prepared by the reduction of SeO2 with sulphur dioxide and hydrazine hydrate is studied. It is observed that the sols when exposed to ultrasonic waves become unstable, and get finally completely coagulated. The sol prepared by the reduction with hydrazine hydrate is found to be more resistant to the action of ultrasonic waves which may be due to the adsorbed impurities presumably hydrazine hydrate. The specific conductivity and hydrogen ion concentration increases with the time of exposure to ultrasonic waves. The coagulation of the sol may be due to the fact that the adsorbed SeO3− ions get free by the ultrasonic energy. In the presence of non-electrolytes as ethyl alcohol or acetone the sol becomes more stable to the action of ultrasonic waves.

Influence of ultrasonic waves on tellurium hydrosol

The influence of ultrasonic waves (1 Mc/s 225 watts per sq. cm. electrical output to the transducer) on tellurium hydrosol prepared by the reduction of telluric acid with hydrazine hydrate has been studied in this paper. It is observed that the colloidal phase of the sol disappears on exposing the sol for three hours. The specific conductivity and hydrogen ion concentration shows a continuous increase with the time of exposure to ultrasonic waves. The colour of the sol changes from bluish-brown to colourless. The effect of hydrogen peroxide on the sol is also studied. The sol becomes unstable as soon as the stabilising tellurate and tellurite ions are rendered free under the action of ultrasonic waves. In presence of non-electrolytes as ethyl alcohol and acetone, the sol becomes stable to the action of ultrasonic waves. The changes in hydrogen ion concentration and specific conductivity become small. The colloidal phase does not disappear in three hours of exposure to ultrasonic waves.

Influence of ultrasonic waves on cobaltous hydroxide sol

Ultrasonic agency (1 Mc/s 225 watts per sq. cm. output) can be successfully utilised for the preparation of rather a stable colloidal cobaltous hydroxide sol bearing a positive charge. On exposing this sol to ultrasonic waves, it becomes more stable. The specific conductivity and hydrogen ion concentration of the sol continuously increases with the time of exposure to ultrasonic waves. The viscosity of the sol decreases with the time of exposure to ultrasonic waves. The optical density and coagulation values with electrolytes also increase on exposing the sol to ultrasonic waves. The stability of the sol is probably due to the increase in positive charge on the colloidal particles as the hydrogen ion concentration of the sol has increased on exposure. The change in colour is due to transformation of cobaltous to cobaltic hydroxide by ultrasonic waves.

SOME EFFECTS OF PHOSPHORUS ON THE DEVELOPMENT, THE B VITAMIN CONTENT, AND THE INORGANIC COMPOSITION OF OATS

ganic ions on the content of plant tissue. The principal constituents which have been studied to date include carotene, ascorbic acid, and the inorganic ions. Of the work done on the effects of major elements, the main emphasis has been on the study of plant tissue grown in nutrient solutions completely devoid of one element with very little work done on the effect of high and low concentrations of specific inorganic ions. Recently a number of articles have been published suggesting a relationship between the fertility of soils and human and animal nutrition. Before any positive conclusions are justified as to the mechanism of this relation, a comprehensive study of the effect of varying concentrations of inorganic ions (available to the plant) on the nutritive content of plants will be necessary. The work described in the present paper was designed to study the effect of high and low concentrations of phosphorus on the folie acid, biotin, niacin, calcium pantothenate, and inorganic content of oats. Experimental procedure Wintok Oats no. CI-3424 from the Oklahoma Agricultural Experiment Station were the plants used in this study. The seeds were germinated in flats containing pure quartz sand which had been previously leached with hydorchloric acid and washed with distilled water. The seeds were planted in flats, then watered with distilled water. When 11 days old the seedlings were transplanted into pure quartz sand in four-inch glazed soil jars, and the different treatments were watered with their respective nutrient solutions. The following watering systems was used: Approximately 100 ml. of nutrient solution was introduced into each pot every day. Every fourth day the pots were flushed with distilled water to prevent undue salt accumulation. There were ten pots to each treatment with two plants per pot. The compositions of the nutrient solutions were based on Solution 1, Method B, of Hoagland and Arnon (6) and are listed in table I. The nutrient solu

ROLE OF ANOXIA IN PRODUCTION OF EPILEPTIFORM SEIZURES

For many years different workers have attempted to show that voluntary hyperpnea can produce seizures in a patient with epilepsy. Numerous theories have been advanced for the mode of action, all of them being connected either with changes in the concentration of specific ions in the blood or with alterations in the acid-base equilibrium. In voluntary hyperpnea a state of alkalosis is encountered. Because of this, Lennox¹suggested, for the first time, that anoxia may play a part in the production of seizures, in that in alkalosis the blood gives up oxygen less readily, thereby causing oxygen lack in the tissues. On the basis of this premise it should be possible to predict the occurrence of seizures as the result of voluntary hyperpnea. A review of the literature shows a lack of agreement as to the incidence and mechanism of the production of seizures by hyperventilation or anoxia.²

Cataphoretic Velocity of the Typhoid Bacillus as a Function of Culture Age and Type of Medium

The recent interest of chemists and physicists in surface phenomena has accompanied an increasing attention to interfacial conditions in biological sciences. The bacteriologist now looks hopefully toward electrical measurement of certain surface characteristics as a key to facts inaccessible to former methods. Measurements of ^-potential by microcataphoresis cells have been placed on a sound theoretical basis by Ellis,1 Smoluchowski2 and others, while notable contributions to technic of such measurements have been made by Northrop and Kunitz3 and Abramson.4 Like many another technic involving electrical determinations, however, microcataphoresis presents numerous possibilities for error to inexperienced, while interpretation of f-potential requires mastery of certain hydrodynamic and electrical theorems not usually included in biologist's training. In surveying growing literature on microcataphoresis as applied to bacteriology and immunology, one is struck by large number of experiments which ambitiously attempt to relate f-potential to such large aspects of bacterial activity as virulence and organ-specificity, while number of attempts to determine simple basic variables seems relatively small. There has arisen in certain quarters a tendency to forget or neglect true significance of f-potential: that of a relation between and suspending fluid in which measurements are made, a meaning inherent in word potential, which implies relativity. Thus one finds f-potential considered by some as an absolute characteristic of a given organism, much like ability to ferment lactose or reaction to Gram stain. It is needless to refer here to large volume of experimental work which has demonstrated f-potential to vary in a generally predictable way with concentration of specific ions in suspending medium, or to point out that to speak of the f-potential of an organism without reference to medium in which it is measured is just as meaningless as to speak of velocity of a man without stating whether he is moving on land, swimming in water or falling freely through space. Even among those who well appreciate relativity of f-potential, however, there prevails feeling that if ionic concentration is carefully controlled and suspending medium kept constant in all other respects, then