Oxygen binding to Arabidopsis thaliana AHb2 nonsymbiotic hemoglobin: evidence for a role in oxygen transport

IUBMB Life ◽  
2011 ◽  
Vol 63 (5) ◽  
pp. 355-362 ◽  
Author(s):  
Francesca Spyrakis ◽  
Stefano Bruno ◽  
Axel Bidon-Chanal ◽  
Francisco Javier Luque ◽  
Stefania Abbruzzetti ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Oxygen Transport ◽  
Oxygen Binding

Oxygen transport by rabbit embryonic blood: high cooperativity of hemoglobin-oxygen binding

1995 ◽  
Vol 99 (1) ◽  
pp. 157-164 ◽  
Author(s):  
Robert A.B. Holland ◽  
Susan J. Calvert
Keyword(s):  
Oxygen Transport ◽  
Oxygen Binding

scholarly journals Molecular evolution and expression of oxygen transport genes in livebearing fishes (Poeciliidae) from hydrogen sulfide rich springs

Genome ◽  
2018 ◽  
Vol 61 (4) ◽  
pp. 273-286 ◽  
Author(s):  
Nicholas Barts ◽  
Ryan Greenway ◽  
Courtney N. Passow ◽  
Lenin Arias-Rodriguez ◽  
Joanna L. Kelley ◽  
...  
Keyword(s):  
Gene Expression ◽  
Hydrogen Sulfide ◽  
Molecular Evolution ◽  
Oxygen Transport ◽  
Transport Proteins ◽  
Aquatic Environments ◽  
Oxygen Binding ◽  
The Family ◽  
Signatures Of Selection ◽  
Evolution Of Oxygen

Hydrogen sulfide (H2S) is a natural toxicant in some aquatic environments that has diverse molecular targets. It binds to oxygen transport proteins, rendering them non-functional by reducing oxygen-binding affinity. Hence, organisms permanently inhabiting H2S-rich environments are predicted to exhibit adaptive modifications to compensate for the reduced capacity to transport oxygen. We investigated 10 lineages of fish of the family Poeciliidae that have colonized freshwater springs rich in H2S—along with related lineages from non-sulfidic environments—to test hypotheses about the expression and evolution of oxygen transport genes in a phylogenetic context. We predicted shifts in the expression of and signatures of positive selection on oxygen transport genes upon colonization of H2S-rich habitats. Our analyses indicated significant shifts in gene expression for multiple hemoglobin genes in lineages that have colonized H2S-rich environments, and three hemoglobin genes exhibited relaxed selection in sulfidic compared to non-sulfidic lineages. However, neither changes in gene expression nor signatures of selection were consistent among all lineages in H2S-rich environments. Oxygen transport genes may consequently be predictable targets of selection during adaptation to sulfidic environments, but changes in gene expression and molecular evolution of oxygen transport genes in H2S-rich environments are not necessarily repeatable across replicated lineages.

Effect of Blood Viscosity on Oxygen Transport in Residual Stenosed Artery Following Angioplasty

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
Ohwon Kwon ◽  
Mahesh Krishnamoorthy ◽  
Young I. Cho ◽  
John M. Sankovic ◽  
Rupak K. Banerjee
Keyword(s):  
Flow Rate ◽  
Oxygen Transport ◽  
Blood Viscosity ◽  
Recirculation Zone ◽  
Binding Capacity ◽  
Vasa Vasorum ◽  
Oxygen Binding ◽  
Stenosed Artery ◽  
Hyperemic Flow ◽  
Basal Flow

The effect of blood viscosity on oxygen transport in a stenosed coronary artery during the postangioplasty scenario is studied. In addition to incorporating varying blood viscosity using different hematocrit (Hct) concentrations, oxygen consumption by the avascular wall and its supply from vasa vasorum, nonlinear oxygen binding capacity of the hemoglobin, and basal to hyperemic flow rate changes are included in the calculation of oxygen transport in both the lumen and the avascular wall. The results of this study show that oxygen transport in the postangioplasty residual stenosed artery is affected by non-Newtonian shear-thinning property of the blood viscosity having variable Hct concentration. As Hct increases from 25% to 65%, the diminished recirculation zone for the increased Hct causes the commencement of pO2 decrease to shift radially outward by ∼20% from the center of the artery for the basal flow, but by ∼10% for the hyperemic flow at the end of the diverging section. Oxygen concentration increases from a minimum value at the core of the recirculation zone to over 90mmHg before the lumen-wall interface at the diverging section for the hyperemic flow, which is attributed to increased shear rate and thinner lumen boundary layer for the hyperemic flow, and below 90mmHg for the basal flow. As Hct increases from 25% to 65%, the average of pO2,min beyond the diverging section drops by ∼25% for the basal flow, whereas it increases by ∼15% for the hyperemic flow. Thus, current results with the moderate stenosed artery indicate that reducing Hct might be favorable in terms of increasing O2 flux and pO2,min, in the medial region of the wall for the basal flow, while higher Hct is advantageous for the hyperemic flow beyond the diverging section. The results of this study not only provide significant details of oxygen transport under varying pathophysiologic blood conditions such as unusually high blood viscosity and flow rate, but might also be extended to offer implications for drug therapy related to blood-thinning medication and for blood transfusion and hemorrhage.

scholarly journals Cops and robbers: putative evolution of copper oxygen-binding proteins

2000 ◽  
Vol 203 (12) ◽  
pp. 1777-1782 ◽  
Author(s):  
H. Decker ◽  
N. Terwilliger
Keyword(s):  
Immune Response ◽  
Oxygen Transport ◽  
Active Site ◽  
Binding Proteins ◽  
Primary Immune Response ◽  
Evolutionary Relationships ◽  
Oxygen Binding ◽  
Copper Proteins ◽  
Phenoloxidase Activity ◽  
Cops And Robbers

Two closely related copper proteins, phenoloxidase and haemocyanin, are known to be involved in different physiological functions such as the primary immune response and oxygen transport. Although the proteins differ structurally, they have the same active site by which dioxygen is bound. Recent results reveal that haemocyanin also exhibits phenoloxidase activity. A scenario is proposed for the evolutionary relationships among copper oxygen-binding proteins (COPs).

scholarly journals Acute Acquired Methemoglobinemia Following Nitrobenzene Poisoning

2021 ◽  
Vol 18 (4) ◽  
pp. 798-800
Author(s):  
Samriddh Dhungel ◽  
Prabina Ghimire ◽  
Swarup Shrestha ◽  
Tulsi Bhattarai ◽  
Anil Pokhrel
Keyword(s):  
Patient Outcome ◽  
Methylene Blue ◽  
Vitamin C ◽  
Aromatic Compound ◽  
Clinical Diagnosis ◽  
Oxygen Transport ◽  
Oxygen Binding ◽  
Unconjugated Hyperbilirubinemia ◽  
Prompt Treatment ◽  
Dual Mechanism

Nitrobenzene is an aromatic compound commonly used in agricultural fertilizers. It is capable of inducing methemoglobinemia when ingested in sufficient quantities. Methemoglobinemia impairs oxygen transport by dual mechanism of impaired oxygen binding and diminished oxygen unloading. We report a case of nitrobenzene poisoning accompanied by methemoglobinemia and later complicated by unconjugated hyperbilirubinemia secondary to hemolysis. Prompt treatment with intravenous methylene blue based on a clinical diagnosis in view of dropping SpO2 unresponsive to oxygen with chocolate cyanosis and paradoxically elevated PaO2 enabled favorable patient outcome. Other recommended modalities of treatment in acquired acute methemoglobinemia include vitamin C, hyperbaric oxygen and exchange transfusions.Keywords: Methemoglobinemia; methylene blue; nitrobenzene; nitroboom

scholarly journals The role of catecholamines in erythrocyte pH regulation and oxygen transport in rainbow trout (Salmo gairdneri) during exercise

1986 ◽  
Vol 122 (1) ◽  
pp. 139-148 ◽  
Author(s):  
D. R. Primmett ◽  
D. J. Randall ◽  
M. Mazeaud ◽  
R. G. Boutilier
Keyword(s):  
Rainbow Trout ◽  
Oxygen Transport ◽  
Ph Regulation ◽  
Arterial Oxygen ◽  
Salmo Gairdneri ◽  
Swimming Velocity ◽  
Oxygen Binding ◽  
Arterial Oxygen Content ◽  
Burst Swimming ◽  
Critical Swimming Velocity

Rainbow trout were subjected to burst swimming to exhaustion followed by 4 h aerobic swimming at 80% critical swimming velocity. Severe physiological disturbances, including a marked plasma acidosis caused by the burst swim, were corrected during the 4 h of subsequent aerobic exercise. Erythrocytic pH and arterial oxygen content increased, even though plasma pH was reduced. We suggest that the increase in erythrocytic pH was caused by the action of elevated adrenaline and noradrenaline levels in the blood acting on beta-adrenergic receptors on the trout red blood cell, causing the cell to swell and raising intracellular pH, offsetting any effect of a reduction of plasma pH on erythrocyte pH and haemoglobin-oxygen binding. Propranolol blocked the action of catecholamines on trout erythrocytes. We conclude that catecholamines play an important role in maintaining oxygen transport to aerobic muscles, following burst swimming and the associated acidotic conditions.

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