Search results for "Hemoglobins"
showing 10 items of 181 documents
The Greenland shark Somniosus microcephalus—Hemoglobins and ligand-binding properties
2017
A large amount of data is currently available on the adaptive mechanisms of polar bony fish hemoglobins, but structural information on those of cartilaginous species is scarce. This study presents the first characterisation of the hemoglobin system of one of the longest-living vertebrate species (392 +/- 120 years), the Arctic shark Somniosus microcephalus. Three major hemoglobins are found in its red blood cells and are made of two copies of the same a globin combined with two copies of three very similar beta subunits. The three hemoglobins show very similar oxygenation and carbonylation properties, which are unaffected by urea, a very important compound in marine elasmobranch physiology.…
Characterization of the Heme Pocket Structure and ligand binding kinetics of non-symbiotic hemoglobins from the model legume Lotus japonicus
2017
14 Pags.- 6 Figs. This article is part of the Research Topic: Advances in legume research ( http://journal.frontiersin.org/researchtopic/4288/advances-in-legume-research ). Copyright of the Authors through a Creative Commons Attribution License. This Document is Protected by copyright and was first published by Frontiers. All rights reserved. it is reproduced with permission.
7-Keto-Cholesterol and Cholestan-3beta, 5alpha, 6beta-Triol Induce Eryptosis through Distinct Pathways Leading to NADPH Oxidase and Nitric Oxide Synt…
2019
Background/aims We showed that patho-physiological concentrations of either 7-keto-cholesterol (7-KC), or cholestane-3beta, 5alpha, 6beta-triol (TRIOL) caused the eryptotic death of human red blood cells (RBC), strictly dependent on the early production of reactive oxygen species (ROS). The goal of the current study was to assess the contribution of the erythrocyte ROS-generating enzymes, NADPH oxidase (RBC-NOX), nitric oxide synthase (RBC-NOS) and xanthine oxido-reductase (XOR) to the oxysterol-dependent eryptosis and pertinent activation pathways. Methods Phosphatidylserine exposure at the cell surface was estimated from annexin-V-binding, reactive oxygen/nitrogen species (RONS) and nitri…
Immunological properties of oxygen-transport proteins: hemoglobin, hemocyanin and hemerythrin
2016
It is now well documented that peptides with enhanced or alternative functionality (termed cryptides) can be liberated from larger, and sometimes inactive, proteins. A primary example of this phenomenon is the oxygen-transport protein hemoglobin. Aside from respiration, hemoglobin and hemoglobin-derived peptides have been associated with immune modulation, hematopoiesis, signal transduction and microbicidal activities in metazoans. Likewise, the functional equivalents to hemoglobin in invertebrates, namely hemocyanin and hemerythrin, act as potent immune effectors under certain physiological conditions. The purpose of this review is to evaluate the true extent of oxygen-transport protein dy…
Knockdown of Drosophila hemoglobin suggests a role in O2 homeostasis.
2016
Almost all insects are equipped with a tracheal system, which appears to be sufficient for O2 supply even in phases of high metabolic activity. Therefore, with the exception of a few species dwelling in hypoxic habitats, specialized respiratory proteins had been considered unnecessary in insects. The recent discovery and apparently universal presence of intracellular hemoglobins in insects has remained functionally unexplained. The fruitfly Drosophila melanogaster harbors three different globin genes (referred to as glob1-3). Glob1 is the most highly expressed globin and essentially occurs in the tracheal system and the fat body. To better understand the functions of insect globins, the lev…
Evolution of Hemoglobin Genes in Codfishes Influenced by Ocean Depth
2017
AbstractUnderstanding the genetic basis of adaptation is one of the main enigmas of evolutionary biology. Among vertebrates, hemoglobin has been well documented as a key trait for adaptation to different environments. Here, we investigate the role of hemoglobins in adaptation to ocean depth in the diverse teleost order Gadiformes, with species distributed at a wide range of depths varying in temperature, hydrostatic pressure and oxygen levels. Using genomic data we characterized the full hemoglobin (Hb) gene repertoire for subset of species within this lineage. We discovered a correlation between expanded numbers of Hb genes and ocean depth, with the highest numbers in species occupying sha…
A widely used sampling device in colorectal cancer screening programmes allows for large-scale microbiome studies.
2018
We read with interest the article by Passamonti et al ,1 reporting the performance of two different faecal immunochemical tests (FITs) highlighting the importance of standardisation and validation of screening methodologies. Conventionally, laboratory-based FIT is the preferred approach in testing for occult blood in faeces, which includes colorectal cancer screening programmes.2–4 The potential of preserving stable faecal samples in a widely used FIT buffer for microbiome research would enable prospective microbiome studies in generally healthy subjects undergoing colorectal cancer screening. For this purpose, we evaluated faecal sample stability in the commonly used OC-Sensor (Eiken Chemi…
Central functional response to the novel peptide cannabinoid, hemopressin.
2013
Hemopressin is the first peptide ligand to be described for the CB₁ cannabinoid receptor. Hemopressin acts as an inverse agonist in vivo and can cross the blood-brain barrier to both inhibit appetite and induce antinociception. Despite being highly effective, synthetic CB₁ inverse agonists are limited therapeutically due to unwanted, over dampening of central reward pathways. However, hemopressin appears to have its effect on appetite by affecting satiety rather than reward, suggesting an alternative mode of action which might avoid adverse side effects. Here, to resolve the neuronal circuitry mediating hemopressin's actions, we have combined blood-oxygen-level-dependent, pharmacological-ch…
Structural and Dynamic Properties of the Homodimeric Hemoglobin from Scapharca inaequivalvis Thr-72→Ile Mutant: Molecular Dynamics Simulation, Low Te…
1998
AbstractMolecular dynamics simulations, low temperature visible absorption spectroscopy, and resonance Raman spectroscopy have been performed on a mutant of the Scapharca inaequivalvis homodimeric hemoglobin, where residue threonine 72, at the subunit interface, has been substituted by isoleucine. Molecular dynamics simulation indicates that in the Thr-72→Ile mutant several residues that have been shown to play a role in ligand binding fluctuate around orientations and distances similar to those observed in the x-ray structure of the CO derivative of the native hemoglobin, although the overall structure remains in the T state. Visible absorption spectroscopy data indicate that in the deoxy …
Dependence of plasma pH on oxygen saturation
1969
Abstract The influence of haemoglobin oxygenation on the pH value of the blood plasma of healthy adolescents was investigated at 38°C by varying the parameters CO2 pressure, Hb concentration and buffer bases. A total of 5000 measurements gave the following results: 1. 1. The pHs difference between oxygenated and deoxygenated blood increases with diminishing CO2 pressure and with increasing Hb concentration. There is a linear relation between the pHs changes and the O2 saturation of the haemoglobin. 2. 2. Quantitatively these relationships can be expressed by the following equation: δpHs = (8 − pH ox − log 0.03 Pco 2 ) · [Hb] 225 · (100 − So 2 100 where ΔpHs is the pHs difference between par…