scholarly journals Acid pH induces formation of dense cells in sickle erythrocytes

Blood ◽  
1989 ◽  
Vol 74 (1) ◽  
pp. 487-495 ◽  
Author(s):  
C Brugnara ◽  
T Van Ha ◽  
DC Tosteson
Keyword(s):  
Carbon Monoxide ◽  
Cell Shrinkage ◽  
Density Fractions ◽  
Kcl Cotransport ◽  
Acid Ph ◽  
Sickle Erythrocytes ◽  
Dense Fraction ◽  
Cotransport System ◽  
Constant Cell ◽  
Ph Dependent

When erythrocytes from patients homozygous for hemoglobin S (SS) are swollen or exposed to pH less than 7.40, they lose K, Cl, and water through a volume and pH-dependent KCl cotransport system. We report that carbon monoxide-treated SS cells become progressively denser when incubated for eight to 12 hours in media with pH less than 7.40 (7.3 to 7.0) at constant cell 2,3-diphosphoglycerate (DPG). This phenomenon is maximal in fresh SS cells from the top and middle density fractions, and is absent in cells from the densest fraction. When AA cells are separated according to density, acid pH induces cell shrinkage in the least dense fraction of AA cells, which has considerable KCl cotransport, but produces no change in cell density in the densest fractions of AA erythrocyte, which have no KCl cotransport. These data suggest that dense cells can form in oxygenated SS erythrocytes when the KCl cotransport system is activated by acidification.

scholarly journals Acid pH induces formation of dense cells in sickle erythrocytes

Blood ◽  
1989 ◽  
Vol 74 (1) ◽  
pp. 487-495 ◽  
Author(s):  
C Brugnara ◽  
T Van Ha ◽  
DC Tosteson
Keyword(s):  
Carbon Monoxide ◽  
Cell Shrinkage ◽  
Density Fractions ◽  
Kcl Cotransport ◽  
Acid Ph ◽  
Sickle Erythrocytes ◽  
Dense Fraction ◽  
Cotransport System ◽  
Constant Cell ◽  
Ph Dependent

Abstract When erythrocytes from patients homozygous for hemoglobin S (SS) are swollen or exposed to pH less than 7.40, they lose K, Cl, and water through a volume and pH-dependent KCl cotransport system. We report that carbon monoxide-treated SS cells become progressively denser when incubated for eight to 12 hours in media with pH less than 7.40 (7.3 to 7.0) at constant cell 2,3-diphosphoglycerate (DPG). This phenomenon is maximal in fresh SS cells from the top and middle density fractions, and is absent in cells from the densest fraction. When AA cells are separated according to density, acid pH induces cell shrinkage in the least dense fraction of AA cells, which has considerable KCl cotransport, but produces no change in cell density in the densest fractions of AA erythrocyte, which have no KCl cotransport. These data suggest that dense cells can form in oxygenated SS erythrocytes when the KCl cotransport system is activated by acidification.

scholarly journals Differentiation of acid-ph-dependent and -nondependent entry pathways for mouse hepatitis virus

Virology ◽  
1991 ◽  
Vol 180 (1) ◽  
pp. 108-119 ◽  
Author(s):  
Cora Kooi ◽  
Marguerite Cervin ◽  
Robert Anderson
Keyword(s):  
Hepatitis Virus ◽  
Mouse Hepatitis Virus ◽  
Acid Ph ◽  
Ph Dependent

ROS activate KCl cotransport in nonadherent Ehrlich ascites cells but K+ and Cl− channels in adherent Ehrlich Lettré and NIH3T3 cells

2009 ◽  
Vol 297 (1) ◽  
pp. C198-C206 ◽  
Author(s):  
Ian Henry Lambert ◽  
Thomas Kjær Klausen ◽  
Andreas Bergdahl ◽  
Charlotte Hougaard ◽  
Else Kay Hoffmann
Keyword(s):  
Cell Volume ◽  
Tumor Cells ◽  
Driving Force ◽  
Ehrlich Ascites Tumor ◽  
Adherent Cells ◽  
Ehrlich Ascites Tumor Cells ◽  
Ascites Tumor ◽  
Cell Shrinkage ◽  
Kcl Cotransport ◽  
Ehrlich Ascites

Addition of H2O2 (0.5 mM) to Ehrlich ascites tumor cells under isotonic conditions results in a substantial (22 ± 1%) reduction in cell volume within 25 min. The cell shrinkage is paralleled by net loss of K+, which was significant within 8 min, whereas no concomitant increase in the K+ or Cl− conductances could be observed. The H2O2-induced cell shrinkage was unaffected by the presence of clofilium and clotrimazole, which blocks volume-sensitive and Ca2+-activated K+ channels, respectively, and is unaffected by a raise in extracellular K+ concentration to a value that eliminates the electrochemical driving force for K+. On the other hand, the H2O2-induced cell shrinkage was impaired in the presence of the KCl cotransport inhibitor (dihydro-indenyl)oxyalkanoic acid (DIOA), following substitution of NO3− for Cl−, and when the driving force for KCl cotransport was omitted. It is suggested that H2O2 activates electroneutral KCl cotransport in Ehrlich ascites tumor cells and not K+ and Cl− channels. Addition of H2O2 to hypotonically exposed cells accelerates the regulatory volume decrease and the concomitant net loss of K+, whereas no additional increase in the K+ and Cl− conductance was observed. The effect of H2O2 on cell volume was blocked by the serine-threonine phosphatase inhibitor calyculin A, indicating an important role of serine-threonine phosphorylation in the H2O2-mediated activation of KCl cotransport in Ehrlich cells. In contrast, addition of H2O2 to adherent cells, e.g., Ehrlich Lettré ascites cells, a subtype of the Ehrlich ascites tumor cells, and NIH3T3 mouse fibroblasts increased the K+ and Cl− conductances after hypotonic cell swelling. Hence, H2O2 induces KCl cotransport or K+ and Cl− channels in nonadherent and adherent cells, respectively.

Kinetics and mechanisms of the reaction between carbon monoxide and copper(II) in aqueous solution

1969 ◽  
Vol 47 (2) ◽  
pp. 313-321 ◽  
Author(s):  
J. J. Byerley ◽  
E. Peters
Keyword(s):  
Aqueous Solution ◽  
Carbon Monoxide ◽  
Reaction Path ◽  
Carbonyl Complex ◽  
Cupric Ion ◽  
Inhibiting Effect ◽  
Rate Determining Step ◽  
Ph Dependent ◽  
A Minor ◽  
Kinetics Of

The kinetics of the reduction of copper(II) to copper(I) by carbon monoxide in aqueous solutions have been investigated at 120 °C and carbon monoxide pressures up to 1360 atm. The reaction is homogeneous and proceeds by two paths, one of which is virtually independent of carbon monoxide pressure due to the formation of a stable cuprous carbonyl complex Cu(CO)+. The second reaction path contains both a pH-dependent and pH-independent component. The rate-determining step in both paths appears to be the decomposition of a carbon monoxide insertion complex by a cupric ion. Complexing ligands such as acetate were observed to have a minor inhibiting effect on the overall reaction.

scholarly journals Digestibilities of casein and soya-bean protein in relation to their effects on serum cholesterol in rabbits

1985 ◽  
Vol 54 (2) ◽  
pp. 355-366 ◽  
Author(s):  
Christopher J. H. Woodward ◽  
Kenneth K. Carroll
Keyword(s):  
Heat Treatment ◽  
Serum Cholesterol ◽  
Soya Bean ◽  
Pancreatic Enzymes ◽  
Alkaline Ph ◽  
Acid Ph ◽  
Ph Dependent ◽  
Low Solubility ◽  
Bean Protein

1. Diets containing isolated soya-bean protein induce lower levels of serum cholesterol in animals than diets containing casein. Experiments were conducted to investigate whether differences in digestibility of the proteins might explain this effect.2. At pH 8 with pancreatic enzymes or intestinal peptidase, soya-bean protein was hydrolysed in vitro much less rapidly than casein. However, with pepsin (EC3. 4. 23. 1) at acid pH, soya-bean protein was hydrolysed more rapidly than casein.3. These differences in digestibility may be due to pH-dependent changes in solubility of the proteins. Casein and soya-bean protein were most soluble at alkaline and acid pH respectively.4. Heat treatment of the proteins resulted in lower solubilities and digestibilities. Sonication of soya-bean protein at pH 7.8 increased solubility but only slightly raised digestibility.5. When fed to rabbits, enzymically hydrolysed soya-bean protein induced a 2.3-fold higher concentration of serum cholesterol than did intact soya-bean protein. The hypocholesterolaemic effect of soya-bean protein may be partly attributable to its low solubility and digestibility at alkaline pH.

Deoxygenation of sickle red blood cells stimulates KCl cotransport without affecting Na+/H+exchange

1998 ◽  
Vol 274 (6) ◽  
pp. C1466-C1475 ◽  
Author(s):  
C. H. Joiner ◽  
M. Jiang ◽  
H. Fathallah ◽  
F. Giraud ◽  
R. S. Franco
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Low Density ◽  
Cell Shrinkage ◽  
Kcl Cotransport ◽  
A 23187 ◽  
Dependent Component ◽  
Sickle Red Blood Cells ◽  
Exchange Activity ◽  
External K

KCl cotransport activated by swelling of sickle red blood cells (SS RBC) is inhibited by deoxygenation. Yet recent studies found a Cl−-dependent increase in sickle reticulocyte density with cyclic deoxygenation. This study sought to demonstrate cotransporter stimulation by deoxygenation of SS RBC in isotonic media with normal pH. Low-density SS RBC exhibited a Cl−-dependent component of the deoxygenation-induced net K+efflux, which was blocked by two inhibitors of KCl cotransport, [(dihydroindenyl)oxy]alkanoic acid and okadaic acid. Cl−-dependent K+efflux stimulated by deoxygenation was enhanced 2.5-fold by clamping of cellular Mg2+at the level in oxygenated cells using ionophore A-23187. Incubating cells in high external K+or Rb+minimized inhibition of KCl cotransport by internal Mg2+, and under these conditions deoxygenation markedly stimulated KCl cotransport in the absence of ionophore. Activation of KCl cotransport by deoxygenation of SS RBC in isotonic media at normal pH is consistent with the generalized dephosphorylation of membrane proteins induced by deoxygenation and activation of the cotransporter by a dephosphorylation mechanism. Na+/H+exchange activity, known to be modulated by cytosolic Ca2+elevation and cell shrinkage, remained silent under deoxygenation conditions.

scholarly journals Hypoxia Activates a Ca2+-Permeable Cation Conductance Sensitive to Carbon Monoxide and to GsMTx-4 in Human and Mouse Sickle Erythrocytes

PLoS ONE ◽  
2010 ◽  
Vol 5 (1) ◽  
pp. e8732 ◽  
Author(s):  
David H. Vandorpe ◽  
Chang Xu ◽  
Boris E. Shmukler ◽  
Leo E. Otterbein ◽  
Marie Trudel ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Cation Conductance ◽  
Sickle Erythrocytes ◽  
Human And Mouse

scholarly journals The unique red cell heterogeneity of SC disease: crystal formation, dense reticulocytes, and unusual morphology

Blood ◽  
1991 ◽  
Vol 78 (8) ◽  
pp. 2104-2112 ◽  
Author(s):  
C Lawrence ◽  
ME Fabry ◽  
RL Nagel
Keyword(s):  
Blood Cell ◽  
Compound Heterozygote ◽  
Crystal Formation ◽  
Low Density ◽  
Red Cell ◽  
Cell Heterogeneity ◽  
Billiard Ball ◽  
Density Fractions ◽  
Dense Fraction ◽  
Dramatic Shift

Abstract Knowledge concerning SS (homozygous for the beta s gene) red blood cell (RBC) heterogeneity has been useful for understanding the pathophysiology of sickle cell anemia. No equivalent information exists for RBCs of the compound heterozygote for the beta s and beta c genes (SC) RBCs. These RBCs are known to be denser than most cells in normal blood and even most cells in SS blood (Fabry et al, J Clin Invest 70:1284, 1981). We have analyzed the characteristics of SC RBC heterogeneity and find that: (1) SC cells exhibit unusual morphologic features, particularly the tendency for membrane “folding” (multifolded, unifolded, and triangular shapes are all common); (2) SC RBCs containing crystals and some containing round hemoglobin (Hb) aggregates (billiard-ball cells) are detectable in circulating SC blood; (3) in contrast to normal reticulocytes, which are found mainly in a low-density RBC fraction, SC reticulocytes are found in the densest SC RBC fraction; and (4) both deoxygenation and replacement of extracellular Cl- by NO3- (both inhibitors of K:Cl cotransport) led to moderate depopulation of the dense fraction and a dramatic shift of the reticulocytes to lower density fractions. We conclude that the RBC heterogeneity of SC disease is very different from that of SS disease. The major contributions of properties introduced by HbC are “folded” RBCs, intracellular crystal formation in circulating SC cells, and apparently a very active K:Cl cotransporter that leads to unusually dense reticulocytes.

scholarly journals Single cell, super-resolution imaging reveals an acid pH-dependent conformational switch in SsrB regulates SPI-2

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Andrew Tze Fui Liew ◽  
Yong Hwee Foo ◽  
Yunfeng Gao ◽  
Parisa Zangoui ◽  
Moirangthem Kiran Singh ◽  
...  
Keyword(s):  
Dna Binding ◽  
Single Molecule ◽  
Single Cells ◽  
Super Resolution ◽  
Single Particle Tracking ◽  
Live Cells ◽  
Bacterial Cells ◽  
Acid Ph ◽  
Resolution Imaging ◽  
Ph Dependent

After Salmonella is phagocytosed, it resides in an acidic vacuole. Its cytoplasm acidifies to pH 5.6; acidification activates pathogenicity island 2 (SPI-2). SPI-2 encodes a type three secretion system whose effectors modify the vacuole, driving endosomal tubulation. Using super-resolution imaging in single bacterial cells, we show that low pH induces expression of the SPI-2 SsrA/B signaling system. Single particle tracking, atomic force microscopy, and single molecule unzipping assays identified pH-dependent stimulation of DNA binding by SsrB. A so-called phosphomimetic form (D56E) was unable to bind to DNA in live cells. Acid-dependent DNA binding was not intrinsic to regulators, as PhoP and OmpR binding was not pH-sensitive. The low level of SPI-2 injectisomes observed in single cells is not due to fluctuating SsrB levels. This work highlights the surprising role that acid pH plays in virulence and intracellular lifestyles of Salmonella; modifying acid survival pathways represents a target for inhibiting Salmonella.

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