Handbook of Chemistry and Physics.

Hodgman, Charles D.; Lind, S. C.

doi:10.1021/j150472a018

Cited by 170 publications

(71 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Observations of flagellate morphology and motility were made with a Zeiss IM-35 inverted phase contrast and epifluorescence microscope at 4 0 0~. Flagellate volumes were determined from length (L) and width (W) measurements taken from micrographs made of the experimental populations and calculated as ( 4~/ 3 ) ( L / 2 )~( W / 2 ) from Hodgman et al (1962).…”

Section: Methodsmentioning

confidence: 99%

Unambiguous detection and improved quantification of phagotrophy in apochlorotic nanoflagellates using fluorescent microspheres and concomitant phase contrast and epifluorescence microscopy

Cynar¹,

Sieburth²

1986

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

Recent procedures for quanhfying the ingestion of non-nutritive bacterial sized particles by bacterivores lack the necessary resolution for the accurate determination of ingestion rates. Here, we descnbe how the filter-transfer-freeze procedure of Hewes & Holm-Hansen (1983) permits concomitant epifluorescence and phase contrast microscopy which lets us unambiguously discriminate between lngested and non-ingested fluorescent microspheres (FM) in 4 specles of apochlorotic nanoflagellates. This rapid procedure reduces the subjectivity of grazing rate determlnations while improving precision. We have used this procedure to observe non-continuous feeding, egestion processes and the effect of growth inhibition on phagotrophy.

show abstract

Section: Methodsmentioning

confidence: 99%

Unambiguous detection and improved quantification of phagotrophy in apochlorotic nanoflagellates using fluorescent microspheres and concomitant phase contrast and epifluorescence microscopy

Cynar¹,

Sieburth²

1986

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

show abstract

“…The null point (anaerobiosis) was adjusted after dissolving a few grains of sodium dithionite into aqueous medium in the oxygraph. Equilibration of the electrode system with pure water equilibrated with air at 24°C resulted in a signal which was taken to be equal to 263 f.lM O2 [13] . Secondly, known concentrations of NADH were added to aerobic suspensions of submitochondrial particles, and the Oa scale was calibrated according to the O2 consumed by NADH oxidation (see [14]).…”

Section: Methodsmentioning

confidence: 99%

Cytochrome c Oxidase is a proton pump

Wikström

Krab

1978

FEBS Letters

View full text Add to dashboard Cite

“…The solubility coefficients of oxygen as a function of the concentration of NaCI were determined in the absence of hemoglobin by the couloximetric technique (15). Each solution was equilibrated with air and the amount of dissolved oxygen was compared to the solubility in distilled water using the value of 1.421 AM oxygen per mm Hg (1 mm Hg = 133 Pa) as the solubility coefficient in water (17). The solubility in 0.1 M salt is 97.…”

Section: Methodsmentioning

confidence: 99%

Thermodynamic aspects of the linkage between binding of chloride and oxygen to human hemoglobin

Haire

Hedlund

1977

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Oxygen isotherms of human hemoglobin measured in distilled water and in solutions of sodium chloride in the concentration range from 0.02 to 3.0 M indicate that the oxygen affinity decreases up to about 1 M salt and then begins to increase. The isotherms obtained in the range from 0.02 to 0.6 M sodium chloride, at 370 and pH 7.4, have been analyzed in terms of changes in Gibbs free energy of heme ligation, resulting from the differential interaction between the chloride ion and the two forms of hemoglobin. The maximal theoretical change in Gibbs free energy that chloride ion can exert on the oxygen binding of hemoglobin amounts to 4.9 + 0.2 kcal/mol (21 + 0.8 kJ/mol) of hemoglobin tetramer. A plot of the logarithm of oxygen concentration at half saturation versus the logarithm of the chloride concentration has a slope of 0.40, suggesting 1.6 apparent chloride sites per hemoglobin tetramer. Because the interaction between chloride and hemoglobin is dependent on pH, the apparent thermodynamic linkage between chloride and oxygen binding will also include the salt dependence of the Bohr effect at pH 7.4. The fractional change in Gibbs free energy, measured as a function of the chloride concentration, can be approximated by the binding isotherm between a protein and a 1igand, using an association constant of 11 M-1. Thus, if the number of oxygen-linked chloride sites is more than one per hemoglobin tetramer, these sites must be considered independent. The qualitative effect of neutral salts on the oxygen affinity of hemoglobin has been recognized for a long time (1). The linkage functions describing thermodynamic aspects of homo-and heterotropic effects in hemoglobin chemistry (2-4) have provided a theoretical framework for analysis of the effect of anion binding on heme ligation.The extensive investigation by Rossi-Fanelli and coworkers (5) on the influence of a variety of ions on hemoglobin oxygenation is unfortunately of limited value in terms of quantitative analysis, because the purification method used at that time removed only a fraction of organic phosphates. Benesch et al. (6) showed that the effects of chloride and organic phosphates are competitive and concluded that the influence of chloride on the oxygen isotherm must be due to differential interactions between the ion and the two forms of hemoglobin. A more recent investigation by Antonini et al. (7) showed that the effect of chloride ion on the oxygen isotherm is pH dependent. Thus, both the maximal change in Gibbs free energy of oxygen binding exerted by high concentrations of chloride, and the chloride concentration at which half of the maximal effect is observed, are dependent on the hydrogen ion concentration. A detailed account of the influence of 0.1 M NaCI on the shape of the oxygen isotherms of human hemoglobins A and F compared with the stripped hemoglobins was provided The recent study by Rollema and coworkers (11) has provided additional evidence for the linkage between the alkaline Bohr effect and the differential chloride binding...

show abstract

Handbook of Chemistry and Physics.

Cited by 170 publications

References 0 publications

Unambiguous detection and improved quantification of phagotrophy in apochlorotic nanoflagellates using fluorescent microspheres and concomitant phase contrast and epifluorescence microscopy

Unambiguous detection and improved quantification of phagotrophy in apochlorotic nanoflagellates using fluorescent microspheres and concomitant phase contrast and epifluorescence microscopy

Cytochrome c Oxidase is a proton pump

Thermodynamic aspects of the linkage between binding of chloride and oxygen to human hemoglobin

Contact Info

Product

Resources

About