Differentiation between bicarbonate effect and pH effect on cation accumulation by barley roots

1972 ◽  
Vol 50 (7) ◽  
pp. 1567-1570 ◽  
Author(s):  
J. A. Falade
Keyword(s):  
Ph Effect ◽  
Bathing Solution ◽  
High Ph ◽  
Bicarbonate Effect ◽  
Effects Of Ph

The effects of pH and bicarbonate on cation accumulation by barley roots have been separated. Bicarbonate stimulates but increasing pH inhibits, Na, K, Ca, and Fe absorption. Net enhancement is observed in the absorption of Na and K but depression in that of Fe at high pH in the presence of bicarbonate. The net enhancement is due to the HCO3− present in the bathing solution and the depression is due to pH.

Effect of pH on chloride absorption in the flounder intestine

1988 ◽  
Vol 255 (2) ◽  
pp. G247-G252 ◽  
Author(s):  
A. N. Charney ◽  
J. I. Scheide ◽  
P. M. Ingrassia ◽  
J. A. Zadunaisky
Keyword(s):  
Small Intestine ◽  
Short Circuit ◽  
Ph Effect ◽  
Short Circuit Current ◽  
Bathing Solution ◽  
Solution Ph ◽  
Transport Pathway ◽  
Ussing Chambers ◽  
Chloride Absorption ◽  
In Series

Chloride absorption in the small intestine of the winter flounder, Pseudopleuronectes americanus, is reported to be sensitive to ambient pH. We studied this sensitivity in isolated stripped intestinal mucosa mounted in modified Ussing chambers. Unidirectional 36Cl fluxes (JClm----s, JCls----m) were measured under short-circuited conditions in bathing solutions containing various combinations of HCO3- (0-20 mM), partial pressure of CO2 (0-36 mmHg), and pH (6.77-7.85). We found that JClm----s, net 36Cl flux (JClnet), and short-circuit current (Isc) increased and JCls----m decreased predominately in response to increases in bathing solution pH. There was a linear relationship between pH and both JClnet (r = 0.92, P less than 0.01) and Isc (r = 0.96, P less than 0.005) between pH 6.77 and 7.74. The pH effect was completely reversible, did not require either CO2 or HCO3-, and was not affected by the presence of mucosal barium at 1 mM. Mucosal bumetanide (0.1 mM) completely inhibited the pH effect. These data suggest that the process by which Cl- is absorbed in the flounder intestine is sensitive to pH. The data do not indicate whether pH affects Na+-K+-2Cl- cotransport or a Cl- transport pathway in series with this process. The direction of Cl- absorption in response to pH contrasts with inverse relation of pH and Cl- absorption in mammalian small intestine.

Factors influencing the inorganic speciation of trace metal cations in fresh waters

1999 ◽  
Vol 50 (4) ◽  
pp. 367 ◽  
Author(s):  
Jonathan P. Kim ◽  
Keith A. Hunter ◽  
Malcolm R. Reid
Keyword(s):  
Natural Waters ◽  
Major Ions ◽  
Divalent Cations ◽  
Ion Composition ◽  
High Ph ◽  
River Waters ◽  
Inorganic Complexes ◽  
Effects Of Ph ◽  
Ph Range ◽  
Inorganic Speciation

The effects of pH and major ion composition on the chemical speciation of the divalent cations of Co, Ni, Cu, Zn, Pb and Cd have been examined after consideration of the available thermodynamic database for solution complexes of these ions. Calculations were made for two model river waters representing the 1% and 99% extremes in composition of global river waters. The results show that inorganic speciation behaviour is of two characteristic types: (a) Cu, Zn and Co are dominated by bis-hydroxy- complexes at high pH and show the greatest reduction in the fraction of free aquo ion with increasing pH; (b) Pb, Ni and Cd are dominated by carbonato- complexes at high pH and show a more gradual decrease in the fraction of free aquo ion with increasing pH. For Cu, Pb and Ni significant fractions of the labile forms of these metal ions are present as inorganic complexes in the pH range of most natural waters, whereas for Zn, Co and Cd this is true only at moderately high pH (pH >7.5). Complexing with the major ions SO42– and Cl– is important only at low pH in river waters of high ionic strength.

Radiolysis of aqueous chloroform solutions

1970 ◽  
Vol 48 (2) ◽  
pp. 271-276 ◽  
Author(s):  
B. J. Rezansoff ◽  
K. J. McCallum ◽  
R. J. Woods
Keyword(s):  
Oxalic Acid ◽  
Formic Acid ◽  
Hydroxyl Radicals ◽  
Ph Effect ◽  
Hydrogen Ions ◽  
Γ Radiation ◽  
High Ph ◽  
Hydrated Electrons ◽  
Presence And Absence ◽  
Ph Range

Saturated aqueous chloroform solutions (0.07 M) with pH ranging from 0.8 to 12.6 have been irradiated with 60Co γ-radiation in the presence and absence of air. G(Cl− + ClO−) increases with increasing pH in the pH range 1–3 (aerated solutions) or 3–6 (deaerated solutions) and again at pH greater than 10.5. The variation in yield from aerated solutions in the region pH 1–3 is attributed to competition between chloroform and hydrogen ions for hydrated electrons. However, such competition cannot account for the pH effect observed in deaerated solutions between pH 3 and 6. Increased yields from both aerated and deaerated solutions at high pH are attributed to the formation of O− by reaction of hydroxyl radicals and hydroxide ions. Formic acid and oxalic acid have been identified as minor products when aerated chloroform solutions are irradiated.

Formación y estabilidad de emulsiones de aislados proteicos de soja con diferente contenido de sulfhidrilos libres Formation and stability of emulsions of soy protein isolates with different sulfhydryl content

2000 ◽  
Vol 6 (5) ◽  
pp. 407-414 ◽  
Author(s):  
L.G. Santiago ◽  
A.G. Bonaldo ◽  
R.J. González
Keyword(s):  
Soy Protein ◽  
Activity Index ◽  
Ph Effect ◽  
Surface Concentration ◽  
Coal Surface ◽  
Emulsifying Activity ◽  
Protein Isolates ◽  
Soy Protein Isolates ◽  
Effects Of Ph

This work evaluated the formation and stability of emulsions prepared with three soy protein iso lates with different sulfhydryl content (SHL) and at two different pHs (6.00 and 7.00). Solubility (Sol), emulsifying activity index (IAE), coalescence (%Coal), surface concentration of proteins (r), and ki netics of the creaming process were determined. The effects of pH and sample types or their interac tion were significant (p < 0.05) for the four variables. IAE was little enhanced by the SHL increment, while stability to coalescence decreased. Also, it was verified that Γ is negatively affected by the SHL increment. The pH effect on IAE depended on the SHL. When pH decreased, %Coale lowered and Γ increased. Emulsions destabilized by the floculation-creaming mechanism more slowly at pH 6.00 than at pH 7.00.

scholarly journals The Effects of pH on the Labellar Sugar Receptor of the Fleshfly

1969 ◽  
Vol 53 (4) ◽  
pp. 450-470 ◽  
Author(s):  
Akio Shiraishi ◽  
Hiromichi Morita
Keyword(s):  
Receptor Site ◽  
Low Ph ◽  
The Other ◽  
High Ph ◽  
Sugar Receptor ◽  
Other Hand ◽  
Wide Range ◽  
Effects Of Ph ◽  
Ionizable Groups ◽  
Inhibition Curve

Reproducible results describing the effects of pH on the response of the labellar sugar receptor of the fleshfly, Boettcherisca peregrina, were obtained. The response to sucrose was independent over a wide range of pH (3.0 to 10.0 for sucrose stimulation), but was inhibited fairly sharply on both sides of this range. Similar results were obtained for monosaccharide stimulation. The receptor was excited on stimulation by water above pH 12.0. The effects of high pH, both inhibitory and excitatory, were affected by the presence of salts. In the presence of 0.5 molar NaCl, for example, the pH-inhibition curve was shifted toward lower pH's by about one pH unit. The effects of low pH, on the other hand, were not affected by salts. Following Dixon's theory, it was concluded that at least five ionizable groups (loosing positive charges above pH 10.5) were located at the receptor site.

Na+ transport by mammalian stomach.

1978 ◽  
Vol 234 (3) ◽  
pp. E228 ◽  
Author(s):  
T E Machen ◽  
W Silen ◽  
J G Forte
Keyword(s):  
Short Circuit ◽  
Ph Effect ◽  
Normal Function ◽  
Open Circuit ◽  
Bathing Solution ◽  
Na Transport ◽  
In Vitro Investigation ◽  
Mammalian Stomach

Gastric mucosas from newborn pigs (0--20 days) and rabbits (0--20 days) were used for in vitro investigation of active Na+ transport during resting (no HCl secretion) conditions. As measured with 22Na+, these tissues actively absorb Na+ from the mucosal-to serosal (m-t-s) bathing solution during both open-circuit and short-circuit current (Is) conditions. In the nonsecreting state, net Na+ transport accounts for 40--60% of Isc. The remaining current is provided by net s-to-m flux of Cl-. Amiloride (2-5 X 10(-5) M) in the mucosal solution abolishes this active Na+ transport by inhibiting m-to-s fluxes of Na+ (JNams). In vivo-in vitro experiments showed that active Na+ transport is a normal function of the resting mammalian stomach. Decreasing pH of the mucosal solution below pH 5 reversibly causes decreased current-generating capability of the tissue. Pretreatment of the tissue with amiloride abolishes this pH effect. The implication is that the low pH affects the Na+-entry step into cells. "Titration curves" of current vs. pH had an apparent pK approximately 4.0. Ouabain and K+-free solutions both cause decreases in active Na+ and Cl- current. Calculations indicate that a shunt may account for only a small (less than 30%) percentage of total transepithelial conductance.

Effects of pH on K depolarization and contracture in frog muscles

1979 ◽  
Vol 57 (2) ◽  
pp. 217-219
Author(s):  
Hrvoje Lorković
Keyword(s):  
Rana Temporaria ◽  
Rana Esculenta ◽  
Low Ph ◽  
Fiber Bundles ◽  
Bathing Solution ◽  
Mechanical Tension ◽  
Contraction Coupling ◽  
High K ◽  
Frog Species ◽  
Effects Of Ph

Membrane potential changes and mechanical tension provoked by 20 or 80 mM K at pH 8.0 or 4.5 were measured in muscle fiber bundles from Rana temporaria and Rana esculenta. The bathing solution contained Cl as the main anion. Low pH increased the depolarizing efficiency of high K to about the same degree in muscles of both species of frogs. The tension–[K] relationship was shifted toward lower [K] in muscles from R. temporaria and toward higher [K] in muscles from R. esculenta. It was concluded that the depolarization–contraction coupling was insensitive to pH changes in the former but not in the latter frog species.

Effects of pH on Hg0 Re-Emission in WFGD

2014 ◽  
Vol 960-961 ◽  
pp. 462-468 ◽  
Author(s):  
Yong Qiu ◽  
Hui Wu ◽  
Guang Qian Luo ◽  
Hong Yao
Keyword(s):  
Flue Gas ◽  
Laboratory Experiments ◽  
Low Ph ◽  
Time Span ◽  
Flue Gas Desulfurization ◽  
Solution Theory ◽  
High Ph ◽  
Ph Values ◽  
Effects Of Ph ◽  
Conventional Solution

Gaseous oxidized mercury (Hg2+) in the flue gas is soluble in water and can be captured effectively by Wet flue gas desulfurization (WFGD) system. But in some extent Hg0re-emission happens due to the reduction of absorbed Hg2+, and the pH of slurry is an important factor affecting Hg0re-emission. In this study, the theoretical formulas of slurry pH were derived through the conventional solution theory and then were used to evaluate the factors determining the pH of slurry. A series of laboratory experiments were carried out under N2,CO2and O2/N2atmosphere to measure the Hg0re-emission tendency at different pH values. The results show that the higher the pH, the less Hg2+reduced by S(IV), resulting in the decrease of Hg0re-emission. Under N2atmosphere, the Hg0re-emission was mild at pH>4 while it was dramatic at pH<4. Under O2/N2atmosphere, the addition of O2extended the time span of Hg0re-emission at low pH and increased Hg0re-emission unexpectedly in the latter part of the experiments at high pH. CO2atmosphere almost did not affect Hg0re-emission because of its little effect on the slurry pH.

Regulation of stalk and spore antigen expression in monolayer cultures of Dictyostelium discoideum by pH

Development ◽  
1986 ◽  
Vol 96 (1) ◽  
pp. 131-150
Author(s):  
Janice A. Dominov ◽  
Christopher D. Town
Keyword(s):  
Dictyostelium Discoideum ◽  
Phenotypic Expression ◽  
Cell Formation ◽  
Antigen Expression ◽  
Low Ph ◽  
Stalk Cell ◽  
Protein Antigens ◽  
High Ph ◽  
Monolayer Cultures ◽  
Effects Of Ph

The terminal differentiation of Dictyostelium discoideum cells plated as monolayers with cyclic AMP is dramatically affected by developmental buffer conditions. High pH and addition of weak bases induces spore differentiation while low pH and weak acids favour stalk cell formation. In order to analyse the timing and nature of this regulation we have raised and characterized an anti-stalk serum which we have used together with an anti-spore serum to monitor developmental progression in the monolayer system and to detect the phenotypic effects of pH at earlier stages of development. The stalk serum detects both polysaccharide and protein antigens expressed during the terminal stages of normal development. In monolayer culture, the stalk-specific protein antigen appears precociously, while the timing of prespore vacuole appearance is unaffected. Expression of stalk polysaccharide antigens in monolayer cultures occurs as early as 12 h and is localized in a single subset of cells or region of extracellular space within the small cell clumps that form. The effects of pH (and acid/base) on these phenotype-specific antigens can be detected early in development, shortly after their first appearance. In monolayers of wild-type V12 M2 cells, the low pH regimes appear to act more by suppressing the spore than enhancing the stalk pathway, while the high pH regimes both suppress stalk and enhance spore antigen expression. In monolayers of the sporogenous mutant HM29, low pH regimes both enhance stalk antigen and suppress spore antigen expression. These results show that extracellular pH regulates phenotypic expression during a large part of the differentiation process and is not simply restricted to terminal cytodifferentiation.

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