Sample records for human hemoglobin tetramers

  1. Hemoglobin is present as a canonical α2β2 tetramer in dopaminergic neurons. (United States)

    Russo, Roberta; Zucchelli, Silvia; Codrich, Marta; Marcuzzi, Federica; Verde, Cinzia; Gustincich, Stefano


    Hemoglobin is the oxygen carrier in blood erythrocytes. Oxygen coordination is mediated by α2β2 tetrameric structure via binding of the ligand to the heme iron atom. This structure is essential for hemoglobin function in the blood. In the last few years, expression of hemoglobin has been found in atypical sites, including the brain. Transcripts for α and β chains of hemoglobin as well as hemoglobin immunoreactivity have been shown in mesencephalic A9 dopaminergic neurons, whose selective degeneration leads to Parkinson's disease. To gain further insights into the roles of hemoglobin in the brain, we examined its quaternary structure in dopaminergic neurons in vitro and in vivo. Our results indicate that (i) in mouse dopaminergic cell line stably over-expressing α and β chains, hemoglobin exists as an α2β2 tetramer; (ii) similarly to the over-expressed protein, endogenous hemoglobin forms a tetramer of 64kDa; (iii) hemoglobin also forms high molecular weight insoluble aggregates; and (iv) endogenous hemoglobin retains its tetrameric structure in mouse mesencephalon in vivo. In conclusion, these results suggest that neuronal hemoglobin may be endowed with some of the biochemical activities and biological function associated to its role in erythroid cells. This article is part of a Special Issue entitled: Oxygen Binding and Sensing Proteins.

  2. Human hemoglobin genetics

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    Honig, G.R.; Adams, J.G.


    This book contains the following 10 chapters: Introduction; The Human Hemoglobins; The Human Globin Genes; Hemoglobin Synthesis and Globin Gene Expression; The Globin Gene Mutations - A. Mechanisms and Classification; The Globin Gene Mutations - B. Their Phenotypes and Clinical Expression; The Genetics of the Human Globin Gene Loci: Formal Genetics and Gene Linkage; The Geographic Distribution of Globin Gene Variation; Labortory Identification, Screening, Education, and Counseling for Abnormal Hemoglobins and Thalassemias; and Approaches to the Treatment of the Hemoglobin Disorders.

  3. Biophysical characterization of the dimer and tetramer interface interactions of the human cytosolic malic enzyme.

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    Sujithkumar Murugan

    Full Text Available The cytosolic NADP(+-dependent malic enzyme (c-NADP-ME has a dimer-dimer quaternary structure in which the dimer interface associates more tightly than the tetramer interface. In this study, the urea-induced unfolding process of the c-NADP-ME interface mutants was monitored using fluorescence and circular dichroism spectroscopy, analytical ultracentrifugation and enzyme activities. Here, we demonstrate the differential protein stability between dimer and tetramer interface interactions of human c-NADP-ME. Our data clearly demonstrate that the protein stability of c-NADP-ME is affected predominantly by disruptions at the dimer interface rather than at the tetramer interface. First, during thermal stability experiments, the melting temperatures of the wild-type and tetramer interface mutants are 8-10°C higher than those of the dimer interface mutants. Second, during urea denaturation experiments, the thermodynamic parameters of the wild-type and tetramer interface mutants are almost identical. However, for the dimer interface mutants, the first transition of the urea unfolding curves shift towards a lower urea concentration, and the unfolding intermediate exist at a lower urea concentration. Third, for tetrameric WT c-NADP-ME, the enzyme is first dissociated from a tetramer to dimers before the 2 M urea treatment, and the dimers then dissociated into monomers before the 2.5 M urea treatment. With a dimeric tetramer interface mutant (H142A/D568A, the dimer completely dissociated into monomers after a 2.5 M urea treatment, while for a dimeric dimer interface mutant (H51A/D90A, the dimer completely dissociated into monomers after a 1.5 M urea treatment, indicating that the interactions of c-NADP-ME at the dimer interface are truly stronger than at the tetramer interface. Thus, this study provides a reasonable explanation for why malic enzymes need to assemble as a dimer of dimers.

  4. Preparation and Identification of HLA-A*1101 Tetramer Loading with Human Cytomegalovirus pp65 Antigen Peptide

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    Fengyao Li; Lihui Xu; Qingbing Zha; Xiaoyun Chi; Qiantao Jia; Xianhui He


    MHC/peptide tetramer technology has been widely used to study antigen-specific T cells, especially for identifying virus-specific CD8+ T cells in humans. The tetramer molecule is composed of HLA heavy chain, β2-microglobulin (β2m), an antigenic peptide, and fluorescent-labeled streptavidin. To further investigate the HLA-A*1101-restricted CD8+ T cell responses against human cytomegalovirus (HCMV), we established an approach to prepare HLA-A*1101 tetramer complexed with a peptide from HCMV. The cDNA encoding HLA-A*1101 heavy chain was cloned and the prokaryotic expression vector for the ectodomain of HLA-A*1101 fused with a BirA substrate peptide (HLA-A*1101-BSP) at its carboxyl terminus was constructed. The fusion protein was highly expressed as inclusion bodies under optimized conditions in Escherichia coli. Moreover, HLA-A*1101-BSP protein was refolded in the presence of β2m and an HCMV peptide pp6516-24 (GPISGHVLK, GPI). Soluble HLA-A*1101-GPI monomer was biotinylated and purified to a purity of 95%, which was subsequently combined with streptavidin to form tetramers at a yield of > 80%. The HLA-A*1101-GPI tetramers could bind to virus-specific CD8+ T cells,suggesting soluble HLA-A*1101-GPI tetramers were biologically functional. This study provides the basis for further evaluation of HLA-A*1101-restricted CD8+ T cell responses against HCMV infection.

  5. Determination of Human Hemoglobin Derivatives. (United States)

    Attia, Atef M M; Ibrahim, Fatma A A; Abd El-Latif, Noha A; Aziz, Samir W; Abdelmottaleb Moussa, Sherif A; Elalfy, Mohsen S


    The levels of the inactive hemoglobin (Hb) pigments [such as methemoglobin (metHb), carboxyhemoglobin (HbCO) and sulfohemoglobin (SHb)] and the active Hb [in the oxyhemoglobin (oxyHb) form] as well as the blood Hb concentration in healthy non pregnant female volunteers were determined using a newly developed multi-component spectrophotometric method. The results of this method revealed values of SHb% in the range (0.0727-0.370%), metHb% (0.43-1.0%), HbCO% (0.4-1.52%) and oxyHb% (97.06-98.62%). Furthermore, the results of this method revealed values of blood Hb concentration in the range (12.608-15.777 g/dL). The method is highly sensitive, accurate and reproducible.

  6. Specificity for human hemoglobin enhances Staphylococcus aureus infection (United States)

    Pishchany, Gleb; McCoy, Amanda L.; Torres, Victor J.; Krause, Jens C.; Crowe, James E.; Fabry, Mary E.; Skaar, Eric P.


    SUMMARY Iron is required for bacterial proliferation and Staphylococcus aureus steals this metal from host hemoglobin during invasive infections. This process involves hemoglobin binding to the cell wall of S. aureus, heme extraction, passage through the cell envelope, and degradation to release free iron. Herein we demonstrate an enhanced ability of S. aureus to bind hemoglobin derived from humans as compared to other mammals. Increased specificity for human hemoglobin (hHb) translates into an improved ability to acquire iron and is entirely dependent on the staphylococcal hemoglobin receptor IsdB. This feature affects host-pathogen interaction as demonstrated by the increased susceptibility of hHb expressing mice to systemic staphylococcal infection. Interestingly, enhanced utilization of human hemoglobin is not a uniform property of all bacterial pathogens. These results suggest a step in the evolution of S. aureus to better colonize the human host and establish hHb expressing mice as a model of S. aureus pathogenesis. PMID:21147468

  7. Polychelated cryogels: hemoglobin adsorption from human blood. (United States)

    Erol, Kadir


    The separation and purification methods are extremely important for the hemoglobin (Hb) which is a crucial biomolecule. The adsorption technique is popular among these methods and the cryogels have been used quite much due to their macropores and interconnected flow channels. In this study, the Hb adsorption onto the Cu(II) immobilized poly(2-hydroxyethyl methacrylate-glycidyl methacrylate), poly(HEMA-GMA)-Cu(II), cryogels was investigated under different conditions (pH, interaction time, initial Hb concentration, temperature and ionic strength) to optimize adsorption conditions. The swelling test, Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscope (SEM), surface area (BET), elemental and ICP-OES analysis were performed for the characterization of cryogels. Polyethyleneimine (PEI) molecule was used as a Cu(II)-chelating ligand. The Hb adsorption capacity of cryogels was determined as 193.8 mg Hb/g cryogel. The isolation of Hb from human blood was also studied under optimum adsorption conditions determined and the Hb (124.5 mg/g cryogel) was isolated. The adsorption model was investigated in the light of Langmuir and Freundlich adsorption isotherm models and it was determined to be more appropriate to the Langmuir adsorption isotherm model.

  8. Preparation and Characterization of HLA-A*0201 Tetramer Loaded with IE-1316-324 Antigenic Peptide of Human Cytomegalovirus

    Institute of Scientific and Technical Information of China (English)

    Lihui Xu; Qingbing Zha; Hong Sun; Qiantao Jia; Fengyao Li; Xianhui He


    Major histocompatibility complex (MHC) class Ⅰ tetramer technology has become the central technique for analyzing antigen-specific CD8+ T cell responses and it has been widely used to explore the differentiation and formation of memory CD8+ T cells. Previously, a simplified and efficient procedure for preparing high quality HLA-A*0201 tetramers has been established in our lab and the tetramers loaded with HCMV peptide pp65495-503has been successfully applied to investigate HCMV-specific CD8+ T cells in Chinese populations. Using similar procedure we reported here the construction of HLA-A*0201 tetramer loaded with another dominant epitope derived from immediate early (IE)-1316-324 (VLEETSVML, VLE) of HCMV (A2-VLE) and characterization of this tetramer. After A2-VLE monomer was prepared and purified, its tetramer was then formed at a yield of 83%. The optimized amount of A2-VLE tetramer for staining 100 μl whole blood was 0.5 μg with incubation at 4℃ for 1 h.Furthermore, the dissociation constant of the tetramer binding to the specific CD8+ T cells of one HLA-A2+ donor was estimated to be 32.7 nmol/L, which is markedly higher than that of MHC monomer. The construction of A2-VLE tetramer provides an alternative choice for investigating HCMV-specific CD8+ T cell responses and will deepen our understanding of the differentiation and formation of HCMV-specific memory CD8+ T cells.

  9. Optical Spectra of Hemoglobin Taken from Alcohol Dependent Humans


    Dudok K.; Dudok T.; Vlokh I.; Vlokh R.


    Optical spectra of CNMetHb and CNMetHb-Coomassi G-250, taken from the blood of humans with alcohol dependence, are studied in the spectral range of 450–750nm. The shifts in the spectral absorption maxima of CNMetHb-Coomassi G-250 complexes are observed for the diseased persons with alcohol dependence. The obtained results show that the hemoglobin structure of alcohol dependent humans is changed.

  10. Spontaneous quaternary and tertiary T-R transitions of human hemoglobin in molecular dynamics simulation.

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    Jochen S Hub


    Full Text Available We present molecular dynamics simulations of unliganded human hemoglobin (Hb A under physiological conditions, starting from the R, R2, and T state. The simulations were carried out with protonated and deprotonated HC3 histidines His(beta146, and they sum up to a total length of 5.6 micros. We observe spontaneous and reproducible T-->R quaternary transitions of the Hb tetramer and tertiary transitions of the alpha and beta subunits, as detected from principal component projections, from an RMSD measure, and from rigid body rotation analysis. The simulations reveal a marked asymmetry between the alpha and beta subunits. Using the mutual information as correlation measure, we find that the beta subunits are substantially more strongly linked to the quaternary transition than the alpha subunits. In addition, the tertiary populations of the alpha and beta subunits differ substantially, with the beta subunits showing a tendency towards R, and the alpha subunits showing a tendency towards T. Based on the simulation results, we present a transition pathway for coupled quaternary and tertiary transitions between the R and T conformations of Hb.

  11. Staphylococcus aureus uses a novel multidomain receptor to break apart human hemoglobin and steal its heme. (United States)

    Spirig, Thomas; Malmirchegini, G Reza; Zhang, Jiang; Robson, Scott A; Sjodt, Megan; Liu, Mengyao; Krishna Kumar, Kaavya; Dickson, Claire F; Gell, David A; Lei, Benfang; Loo, Joseph A; Clubb, Robert T


    Staphylococcus aureus is a leading cause of life-threatening infections in the United States. It requires iron to grow, which must be actively procured from its host to successfully mount an infection. Heme-iron within hemoglobin (Hb) is the most abundant source of iron in the human body and is captured by S. aureus using two closely related receptors, IsdH and IsdB. Here we demonstrate that each receptor captures heme using two conserved near iron transporter (NEAT) domains that function synergistically. NMR studies of the 39-kDa conserved unit from IsdH (IsdH(N2N3), Ala(326)-Asp(660)) reveals that it adopts an elongated dumbbell-shaped structure in which its NEAT domains are properly positioned by a helical linker domain, whose three-dimensional structure is determined here in detail. Electrospray ionization mass spectrometry and heme transfer measurements indicate that IsdH(N2N3) extracts heme from Hb via an ordered process in which the receptor promotes heme release by inducing steric strain that dissociates the Hb tetramer. Other clinically significant Gram-positive pathogens capture Hb using receptors that contain multiple NEAT domains, suggesting that they use a conserved mechanism.

  12. Staphylococcus aureus Uses a Novel Multidomain Receptor to Break Apart Human Hemoglobin and Steal Its Heme* (United States)

    Spirig, Thomas; Malmirchegini, G. Reza; Zhang, Jiang; Robson, Scott A.; Sjodt, Megan; Liu, Mengyao; Krishna Kumar, Kaavya; Dickson, Claire F.; Gell, David A.; Lei, Benfang; Loo, Joseph A.; Clubb, Robert T.


    Staphylococcus aureus is a leading cause of life-threatening infections in the United States. It requires iron to grow, which must be actively procured from its host to successfully mount an infection. Heme-iron within hemoglobin (Hb) is the most abundant source of iron in the human body and is captured by S. aureus using two closely related receptors, IsdH and IsdB. Here we demonstrate that each receptor captures heme using two conserved near iron transporter (NEAT) domains that function synergistically. NMR studies of the 39-kDa conserved unit from IsdH (IsdHN2N3, Ala326–Asp660) reveals that it adopts an elongated dumbbell-shaped structure in which its NEAT domains are properly positioned by a helical linker domain, whose three-dimensional structure is determined here in detail. Electrospray ionization mass spectrometry and heme transfer measurements indicate that IsdHN2N3 extracts heme from Hb via an ordered process in which the receptor promotes heme release by inducing steric strain that dissociates the Hb tetramer. Other clinically significant Gram-positive pathogens capture Hb using receptors that contain multiple NEAT domains, suggesting that they use a conserved mechanism. PMID:23132864

  13. Nonenzymatic glycosylation of human hemoglobin at multiple sites

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    Shapiro, R.; McManus, M.; Garrick, L.; McDonald, M.J.; Bunn, H.F.


    The most abundant minor hemoglobin component of human hemolysate is Hb A1c, which has glucose bound to the N-terminus of the beta chain by a ketoamine linkage. Hb A1c is formed slowly and continuously throughout the 120 day lifespan of the red cell. It can be synthesized in vitro by incubating purified hemoglobin with 14C-glucose. Other minor components, Hb A1a1 and Hb A1a2 are adducts of sugar phosphates at the N-terminus of the beta chain. Hb A1b contains an unidentified nonphosphorylated sugar at the beta N-terminus. In addition, a significant portion of the major hemoglobin component (Hb Ao) is also glycosylated by a glucose ketoamine linkage at other sites on the molecule, including the N-terminus of the alpha chain and the epsilon-amino group of several lysine residues on both the alpha and the beta chains. The results indicate that the interaction of glucose and hemoglobin is rather nonspecific and suggests that other proteins are modified in a similar fashion.

  14. Convergent evolution of hemoglobin switching in jawed and jawless vertebrates. (United States)

    Rohlfing, Kim; Stuhlmann, Friederike; Docker, Margaret F; Burmester, Thorsten


    During development, humans and other jawed vertebrates (Gnathostomata) express distinct hemoglobin genes, resulting in different hemoglobin tetramers. Embryonic and fetal hemoglobin have higher oxygen affinities than the adult hemoglobin, sustaining the oxygen demand of the developing organism. Little is known about the expression of hemoglobins during development of jawless vertebrates (Agnatha). We identified three hemoglobin switches in the life cycle of the sea lamprey. Three hemoglobin genes are specifically expressed in the embryo, four genes in the filter feeding larva (ammocoete), and nine genes correspond to the adult hemoglobin chains. During the development from the parasitic to the reproductive adult, the composition of hemoglobin changes again, with a massive increase of chain aHb1. A single hemoglobin chain is expressed constitutively in all stages. We further showed the differential expression of other globin genes: Myoglobin 1 is most highly expressed in the reproductive adult, myoglobin 2 expression peaks in the larva. Globin X1 is restricted to the embryo; globin X2 was only found in the reproductive adult. Cytoglobin is expressed at low levels throughout the life cycle. Because the hemoglobins of jawed and jawless vertebrates evolved independently from a common globin ancestor, hemoglobin switching must also have evolved convergently in these taxa. Notably, the ontogeny of sea lamprey hemoglobins essentially recapitulates their phylogeny, with the embryonic hemoglobins emerging first, followed by the evolution of larval and adult hemoglobins.

  15. Differential sensitivity of Chironomus and human hemoglobin to gamma radiation

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    Gaikwad, Pallavi S. [Stress Biology Research Laboratory, Department of Zoology, Savitribai Phule University, Pune, 411007 (India); Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085 (India); Panicker, Lata [Solid State Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085 (India); Mohole, Madhura; Sawant, Sangeeta [Bioinformatics Center, Savitribai Phule Pune University, Pune, 411007 (India); Mukhopadhyaya, Rita [Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085 (India); Nath, Bimalendu B., E-mail: [Stress Biology Research Laboratory, Department of Zoology, Savitribai Phule University, Pune, 411007 (India)


    Chironomus ramosus is known to tolerate high doses of gamma radiation exposure. Larvae of this insect possess more than 95% of hemoglobin (Hb) in its circulatory hemolymph. This is a comparative study to see effect of gamma radiation on Hb of Chironomus and humans, two evolutionarily diverse organisms one having extracellular and the other intracellular Hb respectively. Stability and integrity of Chironomus and human Hb to gamma radiation was compared using biophysical techniques like Dynamic Light Scattering (DLS), UV-visible spectroscopy, fluorescence spectrometry and CD spectroscopy after exposure of whole larvae, larval hemolymph, human peripheral blood, purified Chironomus and human Hb. Sequence- and structure-based bioinformatics methods were used to analyze the sequence and structural similarities or differences in the heme pockets of respective Hbs. Resistivity of Chironomus Hb to gamma radiation is remarkably higher than human Hb. Human Hb exhibited loss of heme iron at a relatively low dose of gamma radiation exposure as compared to Chironomus Hb. Unlike human Hb, the heme pocket of Chironomus Hb is rich in aromatic amino acids. Higher hydophobicity around heme pocket confers stability of Chironomus Hb compared to human Hb. Previously reported gamma radiation tolerance of Chironomus can be largely attributed to its evolutionarily ancient form of extracellular Hb as evident from the present study. -- Highlights: •Comparison of radiation tolerant Chironomus Hb and radiation sensitive Human Hb. •Amino acid composition of midge and human heme confer differential hydrophobicity. •Heme pocket of evolutionarily ancient midge Hb provide gamma radiation resistivity.

  16. Differential sensitivity of Chironomus and human hemoglobin to gamma radiation. (United States)

    Gaikwad, Pallavi S; Panicker, Lata; Mohole, Madhura; Sawant, Sangeeta; Mukhopadhyaya, Rita; Nath, Bimalendu B


    Chironomus ramosus is known to tolerate high doses of gamma radiation exposure. Larvae of this insect possess more than 95% of hemoglobin (Hb) in its circulatory hemolymph. This is a comparative study to see effect of gamma radiation on Hb of Chironomus and humans, two evolutionarily diverse organisms one having extracellular and the other intracellular Hb respectively. Stability and integrity of Chironomus and human Hb to gamma radiation was compared using biophysical techniques like Dynamic Light Scattering (DLS), UV-visible spectroscopy, fluorescence spectrometry and CD spectroscopy after exposure of whole larvae, larval hemolymph, human peripheral blood, purified Chironomus and human Hb. Sequence- and structure-based bioinformatics methods were used to analyze the sequence and structural similarities or differences in the heme pockets of respective Hbs. Resistivity of Chironomus Hb to gamma radiation is remarkably higher than human Hb. Human Hb exhibited loss of heme iron at a relatively low dose of gamma radiation exposure as compared to Chironomus Hb. Unlike human Hb, the heme pocket of Chironomus Hb is rich in aromatic amino acids. Higher hydophobicity around heme pocket confers stability of Chironomus Hb compared to human Hb. Previously reported gamma radiation tolerance of Chironomus can be largely attributed to its evolutionarily ancient form of extracellular Hb as evident from the present study.

  17. Effect of laser radiation on physicochemical and functional properties of human hemoglobin in vitro

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    Irzhak, LI; Zotova, EA; Mamaeva, SA


    Exposure to laser radiation increases pH and isoelectric point of human hemoglobin solution, improves the acid-base properties, increases affinity for oxygen, and decreases the Bohr effect in comparison with intact hemoglobin. The mechanisms underlying these changes are discussed.

  18. Analysis of the binding interaction in uric acid - Human hemoglobin system by spectroscopic techniques (United States)

    Makarska-Bialokoz, Magdalena


    The binding interaction between human hemoglobin and uric acid has been studied for the first time, by UV-vis absorption and steady-state, synchronous and three-dimensional fluorescence techniques. Characteristic effects observed for human hemoglobin intrinsic fluorescence during interaction with uric acid at neutral pH point at the formation of stacking non-covalent and non-fluorescent complexes. All the calculated parameters, the binding, fluorescence quenching and bimolecular quenching rate constants, as well as Förster resonance energy transfer parameters confirm the existence of static quenching. The results of synchronous fluorescence measurements indicate that the fluorescence quenching of human hemoglobin originates both from Trp and Tyr residues and that the addition of uric acid could significantly hinder the physiological functions of human hemoglobin.

  19. A haptoglobin-hemoglobin receptor conveys innate immunity to Trypanosoma brucei in humans

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    Vanhollebeke, Benoit; De Muylder, Géraldine; Nielsen, Marianne J


    binds the haptoglobin-hemoglobin complex with high affinity for the uptake and incorporation of heme into intracellular hemoproteins. In mice, this receptor was required for optimal parasite growth and the resistance of parasites to the oxidative burst by host macrophages. In humans, the trypanosome...... receptor also recognized the complex between hemoglobin and haptoglobin-related protein, which explains its ability to capture trypanolytic HDLs. Thus, in humans the presence of haptoglobin-related protein has diverted the function of the trypanosome haptoglobin-hemoglobin receptor to elicit innate host...

  20. Inhibition of pseudoperoxiadse activity of human red blood cell hemoglobin by methocarbamol. (United States)

    Minai-Tehrani, Dariush; Toofani, Sara; Yazdi, Fatemeh; Minai-Tehrani, Arash; Mollasalehi, Hamidreza; Bakhtiari Ziabari, Kourosh


    After red blood cells lysis, hemoglobin is released to blood circulation. Hemoglobin is carried in blood by binding to haptoglobin. In normal individuals, no free hemoglobin is observed in the blood, because most of the hemoglobin is in the form of haptoglobin complex. In some diseases that are accompanied by hemolysis, the amount of released hemoglobin is higher than its complementary haptoglobin. As a result, free hemoglobin appears in the blood, which is a toxic compound for these patients and may cause renal failure, hypertensive response and risk of atherogenesis. Free hemoglobin has been determined to have peroxidase activity and considered a pseudoenzyme. In this study, the effect of methocarbamol on the peroxidase activity of human hemoglobin was investigated. Our results showed that the drug inhibited the pseudoenzyme by un-competitive inhibition. Both Km and Vmax decreased by increasing the drug concentration. Ki and IC50 values were determined as 6 and 10mM, respectively. Docking results demonstrated that methocarbamol did not attach to heme group directly. A hydrogen bond linked NH2 of carbamate group of methocarbamol to the carboxyl group of Asp126 side chain. Two other hydrogen bonds could be also observed between hydroxyl group of the drug and Ser102 and Ser133 residues of the pseudoenzyme.

  1. Lyophilized bovine hemoglobin as a possible reference material for the determination of hemoglobin derivatives in human blood

    NARCIS (Netherlands)

    Maas, BHA; Buursma, A; Ernst, RAJ; Maas, AHJ; Zijlstra, WG


    We investigated the suitability of a lyophilized bovine hemoglobin (LBH) preparation containing various fractions of oxyhemoglobin (O(2)Hb), carboxyhemoglobin (COHb), and methemoglobin (MetHb) for quality assessment in multicomponent analysis (MCA) of hemoglobin derivatives. It was demonstrated that

  2. Effect of the N-terminal residues on the quaternary dynamics of human adult hemoglobin (United States)

    Chang, Shanyan; Mizuno, Misao; Ishikawa, Haruto; Mizutani, Yasuhisa


    The protein dynamics of human hemoglobin following ligand photolysis was studied by time-resolved resonance Raman spectroscopy. The time-resolved spectra of two kinds of recombinant hemoglobin expressed in Escherichia coli, normal recombinant hemoglobin and the α(V1M)/β(V1M) double mutant, were compared with those of human adult hemoglobin (HbA) purified from blood. A frequency shift of the iron-histidine stretching [ν(Fe-His)] band was observed in the time-resolved spectra of all three hemoglobin samples, indicative of tertiary and quaternary changes in the protein following photolysis. The spectral changes of the α(V1M)/β(V1M) double mutant were distinct from those of HbA in the tens of microseconds region, whereas the spectral changes of normal recombinant hemoglobin were similar to those of HbA isolated from blood. These results demonstrated that a structural change in the N-termini is involved in the second step of the quaternary structure change of hemoglobin. We discuss the implications of these results for understanding the allosteric pathway of HbA.

  3. Engineering the oxygen sensing regulation results in an enhanced recombinant human hemoglobin production by Saccharomyces cerevisiae. (United States)

    Martínez, José L; Liu, Lifang; Petranovic, Dina; Nielsen, Jens


    Efficient production of appropriate oxygen carriers for transfusions (blood substitutes or artificial blood) has been pursued for many decades, and to date several strategies have been used, from synthetic polymers to cell-free hemoglobin carriers. The recent advances in the field of metabolic engineering also allowed the generation of different genetically modified organisms for the production of recombinant human hemoglobin. Several studies have showed very promising results using the bacterium Escherichia coli as a production platform, reporting hemoglobin titers above 5% of the total cell protein content. However, there are still certain limitations regarding the protein stability and functionality of the recombinant hemoglobin produced in bacterial systems. In order to overcome these limitations, yeast systems have been proposed as the eukaryal alternative. We recently reported the generation of a set of plasmids to produce functional human hemoglobin in Saccharomyces cerevisiae, with final titers of active hemoglobin exceeding 4% of the total cell protein. In this study, we propose a strategy for further engineering S. cerevisiae by altering the oxygen sensing pathway by deleting the transcription factor HAP1, which resulted in an increase of the final recombinant active hemoglobin titer exceeding 7% of the total cellular protein.

  4. Preservative effects of Aspirin on Human Hemoglobin glycation in Diabetic Condition


    A. Divsalar; J Behroozi; AA Saboury; NN Poursasan


    Abstract Background & aim: Diabetes is a common disease which is characterized by hyperglycemia and the increase of protein glycation. The aim of this study was to investigate the effect of aspirin-induced damage in human hemoglobin in diabetic glycation. Materials & Methods: In this study, hemoglobin extracted from the blood of healthy individuals was incubated in the presence and absence of glucose and aspirin for 5 weeks. The rate of haem glycotation was determined in different cond...

  5. Access to a syllabus of human hemoglobin variants (1996) via the World Wide Web. (United States)

    Hardison, R C; Chui, D H; Riemer, C R; Miller, W; Carver, M F; Molchanova, T P; Efremov, G D; Huisman, T H


    Information on mutations in human hemoglobin is important in many efforts, including understanding the pathophysiology of hemoglobin diseases, developing therapies, elucidating the dynamics of sequence alterations inhuman populations, and dissecting the details of protein structure/function relationships. Currently, information is available on a large number of mutations and variants, but is distributed among thousands of papers. In an effort to organize this voluminous data set, two Syllabi have been prepared compiling succinct information on human hemoglobin abnormalities. In both of these, each entry provides amino acid and/or DNA sequence alterations, hematological and clinical data, methodology used for characterization, ethnic distribution, and functional properties and stability of the hemoglobin, together with appropriate literature references. A Syllabus of Human Hemoglobin Variants (1996) describes 693 abnormal hemoglobins resulting from alterations in the alpha-, beta-, gamma-, and delta-globin chains, including special abnormalities such as double mutations, hybrid chains, elongated chains, deletions, and insertions. We have converted this resource to an electronic form that is accessible via the World Wide Web at the Globin Gene Server ( Hyperlinks are provided from each entry in the tables of variants to the corresponding full description. In addition, a simple query interface allows the user to find all entries containing a designated word or phrase. We are in the process of converting A Syllabus of Thalassemia Mutations (1997) to a similar electronic format.

  6. Scaling properties of universal tetramers. (United States)

    Hadizadeh, M R; Yamashita, M T; Tomio, Lauro; Delfino, A; Frederico, T


    We evidence the existence of a universal correlation between the binding energies of successive four-boson bound states (tetramers), for large two-body scattering lengths (a), related to an additional scale not constrained by three-body Efimov physics. Relevant to ultracold atom experiments, the atom-trimer relaxation peaks for |a|→∞ when the ratio between the tetramer and trimer energies is ≃4.6 and a new tetramer is formed. The new scale is also revealed for a < 0 by the prediction of a correlation between the positions of two successive peaks in the four-atom recombination process.


    Whipple, G H; Robscheit-Robbins, F S


    Human liver tissue has been assayed to determine the amount of hemoglobin production factors in normal and abnormal states. Standardized dogs made anemic by blood removal have been used in this biological assay. Normal animal liver as control is rated as 100 per cent. Normal human liver tissue as compared with the normal animal control contains more of these hemoglobin production factors-a biological assay ratio of 120 to 160 per cent. Infections, acute and chronic, do not appear to modify these values, the concentration of hemoglobin-producing factors falling within the normal range. Pernicious anemia and aplastic anemia both show large liver stores of hemoglobin-producing factors-a biological assay ratio of 200 to 240 per cent. Therapy in pernicious anemia reduces these liver stores as new red cells are formed. Secondary anemia presents a low normal or subnormal liver store of hemoglobin-producing factors-an assay of 60 to 130 per cent. Hemochromatosis, erythroblastic anemia, and hemolytic icterus in spite of large iron deposits in the liver usually show a biological assay which is normal or close to normal. Polycythemia shows low reserve stores of hemoglobin-producing factors. Leukemias present a wide range of values discussed above. Hypoproteinemia almost always is associated with low reserve stores of hemoglobin-producing factors in the liver-biological assays of 60 to 80 per cent. Hypoproteinemia means a depletion of body protein reserve stores including the labile protein liver reserves-a strong indication that the prehemoglobin material (or globin) is related to these liver stores. Pregnancy, eclampsia, and lactation all may present subnormal liver stores of hemoglobin-producing factors. Exhaustion of protein stores lowers the barrier to infection and renders the liver very susceptible to many toxic substances. It should not be difficult to correct hypoproteinemia under these conditions and thus relieve the patient of a real hazard.

  8. Identification and HLA-tetramer-validation of human CD4+ and CD8+ T cell responses against HCMV proteins IE1 and IE2.

    Directory of Open Access Journals (Sweden)

    Peter Braendstrup

    Full Text Available Human cytomegalovirus (HCMV is an important human pathogen. It is a leading cause of congenital infection and a leading infectious threat to recipients of solid organ transplants as well as of allogeneic hematopoietic cell transplants. Moreover, it has recently been suggested that HCMV may promote tumor development. Both CD4+ and CD8+ T cell responses are important for long-term control of the virus, and adoptive transfer of HCMV-specific T cells has led to protection from reactivation and HCMV disease. Identification of HCMV-specific T cell epitopes has primarily focused on CD8+ T cell responses against the pp65 phosphoprotein. In this study, we have focused on CD4+ and CD8+ T cell responses against the immediate early 1 and 2 proteins (IE1 and IE2. Using overlapping peptides spanning the entire IE1 and IE2 sequences, peripheral blood mononuclear cells from 16 healthy, HLA-typed, donors were screened by ex vivo IFN-γ ELISpot and in vitro intracellular cytokine secretion assays. The specificities of CD4+ and CD8+ T cell responses were identified and validated by HLA class II and I tetramers, respectively. Eighty-one CD4+ and 44 CD8+ T cell responses were identified representing at least seven different CD4 epitopes and 14 CD8 epitopes restricted by seven and 11 different HLA class II and I molecules, respectively, in total covering 91 and 98% of the Caucasian population, respectively. Presented in the context of several different HLA class II molecules, two epitope areas in IE1 and IE2 were recognized in about half of the analyzed donors. These data may be used to design a versatile anti-HCMV vaccine and/or immunotherapy strategy.

  9. The structural feature surrounding glycated lysine residues in human hemoglobin. (United States)

    Ito, Shigenori; Nakahari, Takashi; Yamamoto, Daisuke


    Complications derived from diabetes mellitus are caused by nonenzymatic protein glycation at the specific sites. LC/MS/MS was performed for the identification of the tryptic peptides of glycated hemoglobins using glyceraldehyde. After the identification of the glycation or non-glycation site, computer analysis of the structure surrounding the sites was carried out using PDB data (1BZ0). Five glycated lysine residues (Lys-16(α), -56(α), -8(β), -82(β), and -144(β)) and four non-glycated lysine residues (Lys-7(α), -40(α), -99(α), and -132(β)) were identified. The non-glycated lysine residues, Lys-7(α), -40(α), and -132(β), are most likely to form electrostatic interactions with the β carboxyl group of Asp-74(α), C-terminal His-146(β), and Glu-7(β) by virtue of their proximity, which is 2.67-2.91 Å (N-O). Additionally, there are histidine residues within 4.55-7.38 Å (N-N) around eight sites except for Lys-7(α). We conclude that the following factors seem to be necessary for glycation of lysine residues: (i) the apparent absence of aspartate or glutamate residues to inhibit the glycation reaction by forming an electrostatic interaction, (ii) the presence of histidine residues for acid-base catalysis of the Amadori rearrangement, and (iii) the presence of an amino acid residue capable of stabilizing a phosphate during proton transfer.

  10. Human bulbar conjunctival hemodynamics in hemoglobin SS and SC disease. (United States)

    Wanek, Justin; Gaynes, Bruce; Lim, Jennifer I; Molokie, Robert; Shahidi, Mahnaz


    The known biophysical variations of hemoglobin (Hb) S and Hb C may result in hemodynamic differences between subjects with SS and SC disease. The purpose of this study was to measure and compare conjunctival hemodynamics between subjects with Hb SS and SC hemoglobinopathies. Image sequences of the conjunctival microcirculation were acquired in 9 healthy control subjects (Hb AA), 24 subjects with SC disease, and 18 subjects with SS disease, using a prototype imaging system. Diameter (D) and blood velocity (V) measurements were obtained in multiple venules of each subject. Data were categorized according to venule caliber by averaging V and D for venules with diameters less than (vessel size 1) or greater than (vessel size 2) 15 µm. V in vessel size 2 was significantly greater than V in vessel size 1 in the AA and SS groups (P ≥ 0.009), but not in the SC group (P = 0.1). V was significantly lower in the SC group as compared to the SS group (P = 0.03). In AA and SS groups, V correlated with D (P ≤ 0.005), but the correlation was not statistically significant in the SC group (P = 0.08). V was inversely correlated with hematocrit in the SS group for large vessels (P = 0.03); however, no significant correlation was found in the SC group (P ≥ 0.2). Quantitative assessment of conjunctival microvascular hemodynamics in SS and SC disease may advance understanding of sickle cell disease pathophysiology and thereby improve therapeutic interventions.

  11. Adult, embryonic and fetal hemoglobin are expressed in human glioblastoma cells. (United States)

    Emara, Marwan; Turner, A Robert; Allalunis-Turner, Joan


    Hemoglobin is a hemoprotein, produced mainly in erythrocytes circulating in the blood. However, non-erythroid hemoglobins have been previously reported in other cell types including human and rodent neurons of embryonic and adult brain, but not astrocytes and oligodendrocytes. Human glioblastoma multiforme (GBM) is the most aggressive tumor among gliomas. However, despite extensive basic and clinical research studies on GBM cells, little is known about glial defence mechanisms that allow these cells to survive and resist various types of treatment. We have shown previously that the newest members of vertebrate globin family, neuroglobin (Ngb) and cytoglobin (Cygb), are expressed in human GBM cells. In this study, we sought to determine whether hemoglobin is also expressed in GBM cells. Conventional RT-PCR, DNA sequencing, western blot analysis, mass spectrometry and fluorescence microscopy were used to investigate globin expression in GBM cell lines (M006x, M059J, M059K, M010b, U87R and U87T) that have unique characteristics in terms of tumor invasion and response to radiotherapy and hypoxia. The data showed that α, β, γ, δ, ζ and ε globins are expressed in all tested GBM cell lines. To our knowledge, we are the first to report expression of fetal, embryonic and adult hemoglobin in GBM cells under normal physiological conditions that may suggest an undefined function of those expressed hemoglobins. Together with our previous reports on globins (Ngb and Cygb) expression in GBM cells, the expression of different hemoglobins may constitute a part of series of active defence mechanisms supporting these cells to resist various types of treatments including chemotherapy and radiotherapy.

  12. Using the NCBI Genome Databases to Compare the Genes for Human & Chimpanzee Beta Hemoglobin (United States)

    Offner, Susan


    The beta hemoglobin protein is identical in humans and chimpanzees. In this tutorial, students see that even though the proteins are identical, the genes that code for them are not. There are many more differences in the introns than in the exons, which indicates that coding regions of DNA are more highly conserved than non-coding regions.

  13. Determination of the hemoglobin F program in human progenitor-derived erythroid cells.


    Friedman, A.D.; Linch, D. C.; Miller, B.; Lipton, J M; Javid, J; Nathan, D G


    The absolute adult and fetal hemoglobin (HbF) contents of the erythroid cells derived from the differentiation of normal human and simian erythroid progenitors and of the peripheral blood erythroid burst-forming units (BFU-E) of patients with nondeletion hemoglobinopathies have been measured with a sensitive radioligand immunoassay. The HbF content varied between 0.13 and 2.96 pg/cell, representing between 0.7% and 19.6% of the total hemoglobin with a mean value of 7.0%. The absolute content ...

  14. Glycosylated hemoglobin in human and animal red cells. Role of glucose permeability. (United States)

    Higgins, P J; Garlick, R L; Bunn, H F


    We have compared red cells from man and selected animals in order to determine the effect of glucose permeability on nonenzymatic glycosylation of hemoglobin. Glucose permeability was highest in the primates (human, baboon, rhesus monkey), lower in dogs and rabbits, and nearly zero in pigs. Glycosylation of hemoglobin was measured by three independent methods: cation-exchange chromatography on Bio-Rex 70 (Bio-Rad, Inc., Richmond, California), agar gel electrophoresis, and affinity chromatography. The colorimetric thiobarbituric acid test did not provide valid data on animal hemolysates. However, this test was useful for identifying glycosylated hemoglobin (HbA1c) components isolated on Bio-Rex chromatography. In all animals tested, levels of HbA1c (from Bio-Rex chromatography) and total glycosylated hemoglobin (from affinity chromatography) correlated well with glucose exposure, the product of intracellular glucose concentration, and red cell life span. These results indicate that nonenzymatic glycosylation of hemoglobin in mammals is determined by three major variables: mean plasma glucose concentration, red cell life span, and red cell glucose permeability.

  15. Multispectroscopic and calorimetric studies on the binding of the food colorant tartrazine with human hemoglobin. (United States)

    Basu, Anirban; Suresh Kumar, Gopinatha


    Interaction of the food colorant tartrazine with human hemoglobin was studied using multispectroscopic and microcalorimetric techniques to gain insights into the binding mechanism and thereby the toxicity aspects. Hemoglobin spectrum showed hypochromic changes in the presence of tartrazine. Quenching of the fluorescence of hemoglobin occurred and the quenching mechanism was through a static mode as revealed from temperature dependent and time-resolved fluorescence studies. According to the FRET theory the distance between β-Trp37 of hemoglobin and bound tartrazine was evaluated to be 3.44nm. Synchronous fluorescence studies showed that tartrazine binding led to alteration of the microenvironment around the tryptophans more in comparison to tyrosines. 3D fluorescence and FTIR data provided evidence for conformational changes in the protein on binding. Circular dichroism studies revealed that the binding led to significant loss in the helicity of hemoglobin. The esterase activity assay further complemented the circular dichroism data. Microcalorimetric study using isothermal titration calorimetry revealed the binding to be exothermic and driven largely by positive entropic contribution. Dissection of the Gibbs energy change proposed the protein-dye complexation to be dominated by non-polyelectrolytic forces. Negative heat capacity change also corroborated the involvement of hydrophobic forces in the binding process.

  16. Recombinant human erythropoietin and hemoglobin concentration at operation and during the postoperative period

    DEFF Research Database (Denmark)

    Qvist, N; Boesby, S; Wolff, B


    and 750 ml, respectively. The number of blood transfusions given was significantly lower in the erythropoietin group, with a mean of 0.3 (range 0-6) units compared to 1.6 (0-9) units in the control group (p concentration at the time of surgery and during the week......In a double-blind placebo-controlled study we investigated the effect of recombinant human erythropoietin (r-HuEPO), on the perioperative hemoglobin concentration and the use of blood transfusions in patients undergoing elective colorectal surgery with a preoperative hemoglobin level ... for 4 days before surgery. There were no differences between the two groups with regard to sex, height, weight, serum electrolytes, and liver function tests at study entry. The preentry hemoglobin concentration was similar in the two groups, with a median value of 7.9 (range 5.3-8.5) mmol...

  17. Nanosecond absorption study of kinetics associated with carbon monoxide rebinding to hemoglobin S and hemoglobin C following ligand photolysis. (United States)

    Shapiro, D B; Paquette, S J; Esquerra, R M; Che, D; Goldbeck, R A; Hirsch, R E; Mohandas, N; Kliger, D S


    The absorption spectra of photolysis intermediates of the CO complex of hemoglobin S and hemoglobin C, in the tetramer form, have been measured between 10 ns and 200 ms after excitation. These data were analyzed using singular value decomposition (SVD) and global analysis to determine kinetic lifetimes associated with various processes involved in CO recombination. The results of this analysis show that, in the tetramer (non-aggregated) form, hemoglobin S and hemoglobin C exhibit the same kinetics associated with CO recombination as hemoglobin A.

  18. [Influence of mastication on the amount of hemoglobin in human brain tissue]. (United States)

    Sasaki, A


    The purpose of this study was to investigate the influence of mastication on the amount of hemoglobin in human brain tissue. Nine healthy volunteers (6 males and 3 females) participated in this study. They underwent two tasks: 1) at rest, 2) gum-chewing. In seven of the nine (4 males and 3 females), experimental occlusal interference was applied to the first molar of the mandibule on the habitual masticatory side. They underwent the gum-chewing task. To evaluate the amount of hemoglobin, both the hemoglobin oxygenation state and blood volume during gum-chewing were measured in the frontal region, using near-infrared spectroscopy. The amount of total-hemoglobin (blood volume) and oxyhemoglobin of subjects significantly increased during gum-chewing (p < 0.01). When the subjects finished gum-chewing, both levels returned to the original levels. When experimental occlusal interference was imposed on the subject, the amount of them significantly decreased compared with subjects without experimental occlusal interference (p < 0.05). The results suggested that increases of cerebral blood flow in the frontal region were not due to the mandibular movement, and that human brain activity caused by mastication was not only in the cortical masticatory area but also in the frontal region.

  19. Mutations in the paralogous human alpha-globin genes yielding identical hemoglobin variants. (United States)

    Moradkhani, Kamran; Préhu, Claude; Old, John; Henderson, Shirley; Balamitsa, Vera; Luo, Hong-Yuan; Poon, Man-Chiu; Chui, David H K; Wajcman, Henri; Patrinos, George P


    The human alpha-globin genes are paralogues, sharing a high degree of DNA sequence similarity and producing an identical alpha-globin chain. Over half of the alpha-globin structural variants reported to date are only characterized at the amino acid level. It is likely that a fraction of these variants, with phenotypes differing from one observation to another, may be due to the same mutation but on a different alpha-globin gene. There have been very few previous examples of hemoglobin variants that can be found at both HBA1 and HBA2 genes. Here, we report the results of a systematic multicenter study in a large multiethnic population to identify such variants and to analyze their differences from a functional and evolutionary perspective. We identified 14 different Hb variants resulting from identical mutations on either one of the two human alpha-globin paralogue genes. We also showed that the average percentage of hemoglobin variants due to a HBA2 gene mutation (alpha2) is higher than the percentage of hemoglobin variants due to the same HBA1 gene mutation (alpha1) and that the alpha2/alpha1 ratio varied between variants. These alpha-globin chain variants have most likely occurred via recurrent mutations, gene conversion events, or both. Based on these data, we propose a nomenclature for hemoglobin variants that fall into this category.

  20. Ligation-Dependent Picosecond Dynamics in Human Hemoglobin As Revealed by Quasielastic Neutron Scattering. (United States)

    Fujiwara, Satoru; Chatake, Toshiyuki; Matsuo, Tatsuhito; Kono, Fumiaki; Tominaga, Taiki; Shibata, Kaoru; Sato-Tomita, Ayana; Shibayama, Naoya


    Hemoglobin, the vital O2 carrier in red blood cells, has long served as a classic example of an allosteric protein. Although high-resolution X-ray structural models are currently available for both the deoxy tense (T) and fully liganded relaxed (R) states of hemoglobin, much less is known about their dynamics, especially on the picosecond to subnanosecond time scales. Here, we investigate the picosecond dynamics of the deoxy and CO forms of human hemoglobin using quasielastic neutron scattering under near physiological conditions in order to extract the dynamics changes upon ligation. From the analysis of the global motions, we found that whereas the apparent diffusion coefficients of the deoxy form can be described by assuming translational and rotational diffusion of a rigid body, those of the CO form need to involve an additional contribution of internal large-scale motions. We also found that the local dynamics in the deoxy and CO forms are very similar in amplitude but are slightly lower in frequency in the former than in the latter. Our results reveal the presence of rapid large-scale motions in hemoglobin and further demonstrate that this internal mobility is governed allosterically by the ligation state of the heme group.

  1. New Roles Assigned to the α1–β1 (and α2–β2 Interface of the Human Hemoglobin Molecule from Physiological to Cellular

    Directory of Open Access Journals (Sweden)

    Yoshiaki Sugawara


    Full Text Available Cellular life is reliant upon rapid and efficient responses to internal and external conditions. The basic molecular events associated with these processes are the structural transitions of the proteins (structural protein allostery involved. From this view, the human hemoglobin (Hb molecule (α2β2 holds a special position in this field. Hb has two types of αβ interface (i.e., α1β1 [and α2β2] and α1β2 [and α2β1]. The latter α1–β2 (and α2–β1 interface is known to be associated with cooperative O2 binding, and exhibits principal roles if the molecule goes from its deoxy to oxy quaternary structure. However, the role of the former α1–β1 (and α2–β2 interface has been unclear for a long time. In this regard, important and intriguing observations have been accumulating. A new role was attributed first as stabilizing the HbO2 tetramer against acidic autoxidation. That is, the α1–β1 (and α2–β2 interface produces a conformational constraint in the β chain whereby the distal (E7 histidine (His residue is tilted slightly away from the bound O2 so as to prevent proton-catalyzed displacement of O2– by a solvent water molecule. The β chains thus acquire pH-dependent delayed autoxidation in the HbO2 tetramer. The next role was suggested by our studies searching for similar phenomena in normal human erythrocytes under mild heating. Tilting of the distal (E7 His in turn triggered degradation of the Hb molecule to hemichrome, and subsequent clustering of Heinz bodies within the erythrocyte. As Heinz body-containing red cells become trapped in the spleen, it was demonstrated that the α1–β1 (and α2–β2 interface may exert delicate control of the fate (removal of its own erythrocyte. Herein we review and summarize the related results and current interpretation of the oxidative behavior of human Hb, emphasizing the correlation between hemichrome emergence and Heinz-body formation, and specifically discuss the new roles

  2. Hemoglobin derivatives (United States)

    ... this page: // Hemoglobin derivatives To use the sharing features on this page, please enable JavaScript. Hemoglobin derivatives are altered forms of hemoglobin . Hemoglobin is ...

  3. Phylogeny of Echinoderm Hemoglobins.

    Directory of Open Access Journals (Sweden)

    Ana B Christensen

    Full Text Available Recent genomic information has revealed that neuroglobin and cytoglobin are the two principal lineages of vertebrate hemoglobins, with the latter encompassing the familiar myoglobin and α-globin/β-globin tetramer hemoglobin, and several minor groups. In contrast, very little is known about hemoglobins in echinoderms, a phylum of exclusively marine organisms closely related to vertebrates, beyond the presence of coelomic hemoglobins in sea cucumbers and brittle stars. We identified about 50 hemoglobins in sea urchin, starfish and sea cucumber genomes and transcriptomes, and used Bayesian inference to carry out a molecular phylogenetic analysis of their relationship to vertebrate sequences, specifically, to assess the hypothesis that the neuroglobin and cytoglobin lineages are also present in echinoderms.The genome of the sea urchin Strongylocentrotus purpuratus encodes several hemoglobins, including a unique chimeric 14-domain globin, 2 androglobin isoforms and a unique single androglobin domain protein. Other strongylocentrotid genomes appear to have similar repertoires of globin genes. We carried out molecular phylogenetic analyses of 52 hemoglobins identified in sea urchin, brittle star and sea cucumber genomes and transcriptomes, using different multiple sequence alignment methods coupled with Bayesian and maximum likelihood approaches. The results demonstrate that there are two major globin lineages in echinoderms, which are related to the vertebrate neuroglobin and cytoglobin lineages. Furthermore, the brittle star and sea cucumber coelomic hemoglobins appear to have evolved independently from the cytoglobin lineage, similar to the evolution of erythroid oxygen binding globins in cyclostomes and vertebrates.The presence of echinoderm globins related to the vertebrate neuroglobin and cytoglobin lineages suggests that the split between neuroglobins and cytoglobins occurred in the deuterostome ancestor shared by echinoderms and vertebrates.

  4. Identification and HLA-Tetramer-Validation of Human CD4(+) and CD8(+) T Cell Responses against HCMV Proteins IE1 and IE2

    DEFF Research Database (Denmark)

    Braendstrup, Peter; Mortensen, Bo Kok; Justesen, Sune Frederik Lamdahl;


    tumor development. Both CD4(+) and CD8(+) T cell responses are important for long-term control of the virus, and adoptive transfer of HCMV-specific T cells has led to protection from reactivation and HCMV disease. Identification of HCMV-specific T cell epitopes has primarily focused on CD8(+) T cell......-typed, donors were screened by ex vivo IFN-gamma ELISpot and in vitro intracellular cytokine secretion assays. The specificities of CD4(+) and CD8(+) T cell responses were identified and validated by HLA class II and I tetramers, respectively. Eighty-one CD4(+) and 44 CD8(+) T cell responses were identified...... in IE1 and IE2 were recognized in about half of the analyzed donors. These data may be used to design a versatile anti-HCMV vaccine and/or immunotherapy strategy....

  5. Overproduction of alpha chains provides a proton-insensitive component to the bluefish hemoglobin system. (United States)

    Bonaventura, Celia; Godette, Gerald; Stevens, Robert; Brenowitz, Michael; Henkens, Robert


    Expression of alpha and beta chains and their post-translational assembly into alpha(2)beta(2) tetramers is fundamental to the formation and function of most vertebrate hemoglobins. There is a strong evolutionary bias that favors expression of equal amounts of the two types of chains, because cooperativity, pH sensitivity, and anionic control of function occurs only for the alpha(2)beta(2) tetramers. Remarkably, an over-production of alpha chains, as in the pathological condition known as beta thalassemia in humans, is adaptive rather than pathological in the bluefish hemoglobin system. The thalassemia of the bluefish is a novel means of providing for oxygen uptake and delivery when low pH conditions incapacitate the highly pH-sensitive Root effect hemoglobins of the fish. Although fish often have pH-insensitive along with highly pH-sensitive hemoglobins, having pH-insensitive alpha chain monomers in circulation is an unusual structural variation. The role of bluefish alpha chains in oxygen transport is enabled by their remarkably lower oxygen affinity relative to human alpha chains. This is the first reported case of a thalassemic condition that is maintained in a species as an adaptive advantage.

  6. Antimicrobial properties of hemoglobin. (United States)

    Sheshadri, Preethi; Abraham, Jayanthi


    Hemoglobin consists of a heme containing component and a globin unit. It exists as a tetramer with 2 α subunits and 2 β subunits in adults and with 2 α subunits and 2 γ chains in infants. On proteolytic cleavage, hemoglobin breaks down to produce many biologically active compounds, among which are hemocidins, those which exhibit antimicrobial property. The generation of these peptides does not depend on the blood group, Rhesus factor, age and sex of the healthy donors. The microbicidal activity has been observed against a variety of gram positive and Gram-negative bacteria, and against filamentous fungi, yeast and even certain parasites. The discovery of hemocidins opens a new field for research into the details of the peptides acting as second line of defence in boosting the innate immune system of the organisms.

  7. [Identification of rat and human hemoglobin acetilation sites after its interaction with acetylsalicylic acid]. (United States)

    Shreĭner, E V; Murashko, E A; Dubrovskiĭ, Ia D; Krasnov, N V; Podol'skaia, E P; Babakov, V N


    The possibility of interaction of 0.1 mg/mL acetylsalicylic acid with purified human and rat globin in vitro during 24 h at 37 degrees C was investigated. The rat globin can be modified with acetylsalicylic acid on aminoacid residues K-17, K-57, K-91, K-140 in alpha subunit as well as on K-18, K-77 in beta subunit. The human globin can be modified with acetylsalicylic acid on aminoacid residues K-17, K-41, K-57 and K-91 in alpha subunit as well as on K-18, K-96 and K- 133 in beta subunit. We identified of acetetylated lysines K-17 and K-57 in alpha subunit of human hemoglobin after incubation whole blood with 0.1 mg/mL acetylsalicylic acid during 3 h.

  8. One-pot, mix-and-read peptide-MHC tetramers

    DEFF Research Database (Denmark)

    Leisner, Christian Valdemar Vinge; Loeth, Nina; Lamberth, Kasper


    biochemical steps such as chromatographic purification, concentration etc. Such cumbersome production protocols have limited dissemination and restricted availability of peptide-MHC tetramers effectively precluding large-scale screening strategies involving many different peptide-MHC tetramers. METHODOLOGY...... molecules can be refolded in vitro, tetramerized with streptavidin, and used for specific T cell staining-all in a one-pot reaction without any intervening purification steps. CONCLUSIONS/SIGNIFICANCE: We have developed an efficient "one-pot, mix-and-read" strategy for peptide-MHC tetramer generation......, and demonstrated specific T cell straining comparable to a commercially available MHC-tetramer. Here, seven peptide-MHC tetramers representing four different human MHC (HLA) class I proteins have been generated. The technique should be readily extendable to any binding peptide and pre-biotinylated MHC (at...

  9. Interactions of human hemoglobin with charged ligand-functionalized iron oxide nanoparticles and effect of counterions

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Goutam, E-mail: [UGC-DAE Consortium for Scientific Research, Mumbai Centre (India); Panicker, Lata [Bhabha Atomic Research Centre, Solid State Physics Division (India)


    Human hemoglobin is an important metalloprotein. It has tetrameric structure with each subunit containing a ‘heme’ group which carries oxygen and carbon dioxide in blood. In this work, we have investigated the interactions of human hemoglobin (Hb) with charged ligand-functionalized iron oxide nanoparticles and the effect of counterions, in aqueous medium. Several techniques like DLS and ζ-potential measurements, UV–vis, fluorescence, and CD spectroscopy have been used to characterize the interaction. The nanoparticle size was measured to be in the range of 20–30 nm. Our results indicated the binding of Hb with both positively as well as negatively charged ligand-functionalized iron oxide nanoparticles in neutral aqueous medium which was driven by the electrostatic and the hydrophobic interactions. The electrostatic binding interaction was not seen in phosphate buffer at pH 7.4. We have also observed that the ‘heme’ groups of Hb remained unaffected on binding with charged nanoparticles, suggesting the utility of the charged ligand-functionalized nanoparticles in biomedical applications.

  10. Biocompatibility study of protein capped and uncapped silver nanoparticles on human hemoglobin (United States)

    Bhunia, Amit Kumar; Kanti Samanta, Pijus; Aich, Debasish; Saha, Satyajit; Kamilya, Tapanendu


    The interactions of human hemoglobin with protein capped silver nanoparticles and bare silver nanoparticles were studied to understand fundamental perspectives about the biocompatibility of protein capped silver nanoparticles compared with bare silver nanoparticles. Bare silver (Ag) nanoparticles (NPs) were prepared by the chemical reduction method. High resolution transmission electron microscopy (HRTEM) analysis along with absorption at ~390 nm indicated the formation of bare Ag NPs. Protein coated Ag NPs were prepared by a green synthesis method. Absorption at ~440 nm along with ~280 nm indicated the formation of protein coated Ag NPs. The biocompatibility of the above mentioned Ag NPs was studied by interaction with human hemoglobin (Hb) protein. In presence of bare Ag NPs, the Soret band of Hb was red shifted. This revealed the distortion of iron from the heme pockets of Hb. Also, the fluorescence peak of Hb was quenched and red shifted which indicated that Hb became unfolded in the presence of bare Ag NPs. No red shift of the absorption of Soret, along with no shift and quenching of the fluorescence peak of Hb were observed in the presence of protein coated Ag NPs. A hemolysis assay suggested that protein coated Ag NPs were more biocompatible than bare one.

  11. A coordination polymer based magnetic adsorbent material for hemoglobin isolation from human whole blood, highly selective and recoverable (United States)

    Zhang, Xiaoxing; Tan, Jipeng; Xu, Xinxin; Shi, Fanian; Li, Guanglu; Yang, Yiqiao


    A composite material has been obtained successfully through the loading of nanoscale coordination polymer on magnetic Fe3O4@SiO2 core-shell particle. In this composite material, coordination polymer nanoparticles distribute uniformly on Fe3O4@SiO2 and these two components are ;tied; together firmly with chemical bonds. Adsorption experiments suggest this composite material exhibits very excellent selectivity to hemoglobin. But under the same condition, its adsorption to bovine serum albumin can almost be ignored. This selectivity can be attributed to the existence of hydrophobic interactions between coordination polymer nanoparticle and hemoglobin. For composite material, the hemoglobin adsorption process follows Langmuir model perfectly with high speed. The adsorbed hemoglobin can be eluted easily by sodium dodecyl sulfate stripping reagent with structure and biological activity of hemoglobin keeps well. The composite material was also employed to separate hemoglobin from human whole blood, which receives a very satisfactory result. Furthermore, magnetic measurement reveals ferromagnetic character of this composite material with magnetization saturation 3.56 emu g-1 and this guarantees its excellent magnetic separation performance from the treated solution.

  12. Hemoglobin Variants in Mice

    Energy Technology Data Exchange (ETDEWEB)

    Popp, Raymond A.


    Variability among mammalian hemoglobins was observed many years ago (35). The chemical basis for differences among hemoglobins from different species of mammals has been studied by several investigators (5, 11, 18, 48). As well as interspecies differences, hemoglobin variants are frequently found within a species of mammals (2, 3, 7, 16) The inheritance of these intraspecies variants can be studied, and pedigrees indicate that the type of hemoglobin synthesized in an individual is genetically controlled (20). Several of the variant human hemoglobins are f'unctionally deficient (7, 16). Such hemoglobin anomalies are of basic interest to man because of the vital role of hemoglobin for transporting oxygen to all tissues of the body.

  13. Towards hemerythrin-based blood substitutes: Comparative performance to hemoglobin on human leukocytes and umbilical vein endothelial cells

    Indian Academy of Sciences (India)

    Eva Fischer-Fodor; Augustin Mot; Florina Deac; Mariann Arkosi; Radu Silaghi-Dumitrescu


    Hemerythrin is a dioxygen-carrying protein whose oxidative/nitrosative stress-related reactivity is lower than that of hemoglobin, which may warrant investigation of hemerythrin as raw material for artificial oxygen carriers (‘blood substitutes’). We report here the first biological tests for hemerythrin and its chemical derivatives, comparing their performance with that of a representative competitor, glutaraldehyde-polymerized bovine hemoglobin. Hemerythrin (native or derivatized) exhibits a proliferative effect on human umbilical vein endothelial cell (HUVEC) cultures, as opposed to a slight inhibitory effect of hemoglobin. A similar positive effect is displayed on human lymphocytes by glutaraldehyde-polymerized hemerythrin, but not by native or polyethylene glycol-derivatized hemerythrin.

  14. Determining the refractive index of human hemoglobin solutions by Kramers-Kronig relations with an improved absorption model. (United States)

    Gienger, Jonas; Groß, Hermann; Neukammer, Jörg; Bär, Markus


    The real part of the refractive index of aqueous solutions of human hemoglobin is computed from their absorption spectra in the wavelength range 250-1100 nm using the Kramers-Kronig (KK) relations, and the corresponding uncertainty analysis is provided. The strong ultraviolet (UV) and infrared absorbance of the water outside this spectral range were taken into account in a previous study employing KK relations. We improve these results by including the concentration dependence of the water absorbance as well as by modeling the deep UV absorbance of hemoglobin's peptide backbone. The two free parameters of the model for the deep UV absorbance are fixed by a global fit.

  15. One-pot, mix-and-read peptide-MHC tetramers.

    Directory of Open Access Journals (Sweden)

    Christian Leisner

    Full Text Available BACKGROUND: Cytotoxic T Lymphocytes (CTL recognize complexes of peptide ligands and Major Histocompatibility Complex (MHC class I molecules presented at the surface of Antigen Presenting Cells (APC. Detection and isolation of CTL's are of importance for research on CTL immunity, and development of vaccines and adoptive immune therapy. Peptide-MHC tetramers have become important reagents for detection and enumeration of specific CTL's. Conventional peptide-MHC-tetramer production involves recombinant MHC production, in vitro refolding, biotinylation and tetramerization; each step followed by various biochemical steps such as chromatographic purification, concentration etc. Such cumbersome production protocols have limited dissemination and restricted availability of peptide-MHC tetramers effectively precluding large-scale screening strategies involving many different peptide-MHC tetramers. METHODOLOGY/PRINCIPAL FINDINGS: We have developed an approach whereby any given tetramer specificity can be produced within 2 days with very limited effort and hands-on time. The strategy is based on the isolation of correctly oxidized, in vivo biotinylated recombinant MHC I heavy chain (HC. Such biotinylated MHC I HC molecules can be refolded in vitro, tetramerized with streptavidin, and used for specific T cell staining-all in a one-pot reaction without any intervening purification steps. CONCLUSIONS/SIGNIFICANCE: We have developed an efficient "one-pot, mix-and-read" strategy for peptide-MHC tetramer generation, and demonstrated specific T cell straining comparable to a commercially available MHC-tetramer. Here, seven peptide-MHC tetramers representing four different human MHC (HLA class I proteins have been generated. The technique should be readily extendable to any binding peptide and pre-biotinylated MHC (at this time we have over 40 different pre-biotinylated HLA proteins. It is simple, robust, and versatile technique with a very broad application

  16. Hemoglobin (image) (United States)

    Hemoglobin is the most important component of red blood cells. It is composed of a protein called ... exchanged for carbon dioxide. Abnormalities of an individual's hemoglobin value can indicate defects in the normal balance ...

  17. Reactivating Fetal Hemoglobin Expression in Human Adult Erythroblasts Through BCL11A Knockdown Using Targeted Endonucleases

    Directory of Open Access Journals (Sweden)

    Carmen F Bjurström


    Full Text Available We examined the efficiency, specificity, and mutational signatures of zinc finger nucleases (ZFNs, transcriptional activator-like effector nucleases (TALENs, and clustered regularly interspaced short palindromic repeat (CRISPR/Cas9 systems designed to target the gene encoding the transcriptional repressor BCL11A, in human K562 cells and human CD34+ progenitor cells. ZFNs and TALENs were delivered as in vitro transcribed mRNA through electroporation; CRISPR/Cas9 was codelivered by Cas9 mRNA with plasmid-encoded guideRNA (gRNA (pU6.g1 or in vitro transcribed gRNA (gR.1. Analyses of efficacy revealed that for these specific reagents and the delivery methods used, the ZFNs gave rise to more allelic disruption in the targeted locus compared to the TALENs and CRISPR/Cas9, which was associated with increased levels of fetal hemoglobin in erythroid cells produced in vitro from nuclease-treated CD34+ cells. Genome-wide analysis to evaluate the specificity of the nucleases revealed high specificity of this specific ZFN to the target site, while specific TALENs and CRISPRs evaluated showed off-target cleavage activity. ZFN gene-edited CD34+ cells had the capacity to engraft in NOD-PrkdcSCID-IL2Rγnull mice, while retaining multi-lineage potential, in contrast to TALEN gene-edited CD34+ cells. CRISPR engraftment levels mirrored the increased relative plasmid-mediated toxicity of pU6.g1/Cas9 in hematopoietic stem/progenitor cells (HSPCs, highlighting the value for the further improvements of CRISPR/Cas9 delivery in primary human HSPCs.

  18. Characterization of a Hemoglobin Adduct from Ethyl Vinyl Ketone Detected in Human Blood Samples. (United States)

    Carlsson, Henrik; Motwani, Hitesh V; Osterman Golkar, Siv; Törnqvist, Margareta


    Electrophiles have the ability to form adducts to nucleophilic sites in proteins and DNA. Internal exposure to such compounds thus constitutes a risk for toxic effects. Screening of adducts using mass spectrometric methods by adductomic approaches offers possibilities to detect unknown electrophiles present in tissues. Previously, we employed untargeted adductomics to detect 19 unknown adducts to N-terminal valine in hemoglobin (Hb) in human blood. This article describes the characterization of one of these adducts, which was identified as the adduct from ethyl vinyl ketone (EVK). The mean adduct level was 40 ± 12 pmol/g Hb in 12 human blood samples; adduct levels from acrylamide (AA) and methyl vinyl ketone (MVK) were quantified for comparison. Using l-valine p-nitroanilide (Val-pNA), introduced as a model of the N-terminal valine, the rate of formation of the EVK adduct was studied, and the rate constant determined to 200 M(-1)h(-1) at 37 °C. In blood, the reaction rate was too fast to be feasibly measured, EVK showing a half-life adduct was found to be unstable, with a half-life of 7.6 h. From the mean adduct level measured in human blood, a daily dose (area under the concentration-time-curve, AUC) of 7 nMh EVK was estimated. The AUC of AA from intake via food is about 20 times higher. EVK is naturally present in a wide range of foods and is also used as a food additive. Most probably, naturally formed EVK is a major source to observed adducts. Evaluation of available toxicological data and information on occurrence of EVK indicate that further studies of EVK are motivated. This study illustrates a quantitative strategy in the initial evaluation of the significance of an adduct detected through adduct screening.

  19. Cranberry phytochemicals inhibit glycation of human hemoglobin and serum albumin by scavenging reactive carbonyls. (United States)

    Liu, Haiyan; Liu, Hanwei; Wang, Wei; Khoo, Christina; Taylor, James; Gu, Liwei


    Protein glycation caused by sugars and reactive carbonyls is a contributing factor to diabetic complications, aging, and other chronic diseases. The objective of this study was to investigate the inhibitory effects of cranberry phytochemicals on protein glycation. Cranberries, purified to yield sugar-free phytochemical powder, were fractionated into ethyl acetate and water fractions. Water fraction was further separated into water fraction I, II, and III on a Sephadex LH-20 column. Cranberry phytochemical powder and its fractions significantly inhibited the formation of glycated hemoglobin. The concentrations of cranberry phytochemicals required to inhibit 50% of albumin glycation (EC(50)) in albumin-glucose assay were lower than that of aminoguanidine except for water fraction I. Cranberry phytochemicals inhibited glycation of human serum albumin mediated by methylglyoxal, but the EC(50) were higher than that of aminoguanidine. Carbonyl scavenging assay showed that water fraction II scavenged 89.3% of methylglyoxal at 6 h of reaction. Fractions enriched with procyanidins showed higher antiglycation activities, suggesting procyanidins were the major active components. The hypothesis whether cranberry procyanidins scavenged reactive carbonyls by forming adducts was tested. Epicatechin was used as a model compound to react with methylglyoxal and glyoxal at pH 7.4. Five adducts were detected and their structures were tentatively identified using HPLC-ESI-MS/MS.

  20. Inclusion bodies in loggerhead erythrocytes are associated with unstable hemoglobin and resemble human Heinz bodies. (United States)

    Basile, Filomena; Di Santi, Annalisa; Caldora, Mercedes; Ferretti, Luigi; Bentivegna, Flegra; Pica, Alessandra


    The aim of this study was to clarify the role of the erythrocyte inclusions found during the hematological screening of loggerhead population of the Mediterranean Sea. We studied the erythrocyte inclusions in blood specimens collected from six juvenile and nine adult specimens of the loggerhead turtle, Caretta caretta, from the Adriatic and Tyrrhenian Seas. Our study indicates that the percentage of mature erythrocytes containing inclusions ranged from 3 to 82%. Each erythrocyte contained only one round inclusion body. Inclusion bodies stained with May Grünwald-Giemsa show that their cytochemical and ultrastructure characteristics are identical to those of human Heinz bodies. Because Heinz bodies originate from the precipitation of unstable hemoglobin (Hb) and cause globular osmotic resistance to increase, we analyzed loggerhead Hb using electrophoresis and high-performance liquid chromatography to detect and quantitate Hb fractions. We also tested the resistance of Hb to alkaline pH, heat, isopropanol denaturation, and globular osmosis. Our hemogram results excluded the occurrence of any infection, which could be associated with an inclusion body, in all the specimens. Negative Feulgen staining indicated that the inclusion bodies are not derived from DNA fragmentation. We hypothesize that amino acid substitutions could explain why loggerhead Hb precipitates under normal physiologic conditions, forming Heinz bodies. The identification of inclusion bodies in loggerhead erythrocytes allow us to better understand the haematological characteristics and the physiology of these ancient reptiles, thus aiding efforts to conserve such an endangered species. Copyright © 2011 Wiley-Liss, Inc., A Wiley Company.

  1. Acetaminophen interacts with human hemoglobin: optical, physical and molecular modeling studies. (United States)

    Seal, Paromita; Sikdar, Jyotirmoy; Roy, Amartya; Haldar, Rajen


    Acetaminophen, a widely used analgesic and antipyretic drug has ample affinity to bind globular proteins. Here, we have illustrated a substantive study pertaining to the interaction of acetaminophen with human hemoglobin (HHb). Different spectroscopic (absorption, fluorescence, and circular dichroism (CD) spectroscopy), calorimetric, and molecular docking techniques have been employed in this study. Acetaminophen-induced graded alterations in absorbance and fluorescence of HHb confirm their interaction. Analysis of fluorescence quenching at different temperature and data obtained from isothermal titration calorimetry indicate that the interaction is static and the HHb has one binding site for the drug. The negative values of Gibbs energy change (ΔG(0)) and enthalpy changes (ΔH(0)) and positive value of entropy change (ΔS(0)) strongly suggest that it is entropy-driven spontaneous and exothermic reaction. The reaction involves hydrophobic pocket of the protein which is further stabilized by hydrogen bonding as evidenced from ANS and sucrose binding studies. These findings were also supported by molecular docking simulation study using AutoDock 4.2. The interaction influences structural integrity as well as functional properties of HHb as evidenced by CD spectroscopy, increased rate of co-oxidation and decreased esterase activity of HHb. So, from these findings, we may conclude that acetaminophen interacts with HHb through hydrophobic and hydrogen bonding, and the interaction perturbs the structural and functional properties of HHb.

  2. Studies on the interaction of salvianolic acid B with human hemoglobin by multi-spectroscopic techniques (United States)

    Chen, Tingting; Zhu, Shajun; Cao, Hui; Shang, Yanfang; Wang, Miao; Jiang, Guoqing; Shi, Yujun; Lu, Tianhong


    The interaction between salvianolic acid B (Sal B) and human hemoglobin (HHb) under physiological conditions was investigated by UV-vis absorption, fluorescence, synchronous fluorescence and circular dichroism spectroscopic techniques. The experimental results indicate that the quenching mechanism of fluorescence of HHb by Sal B is a static quenching procedure, the binding reaction is spontaneous, and the hydrophobic interactions play a major role in binding of Sal B to HHb. Based on Förster's theory of non-radiative energy transfer, the binding distance between Sal B and the inner tryptophan residues of HHb was determined to be 2.64 nm. The synchronous fluorescence experiment revealed that Sal B can not lead to the microenvironmental changes around the Tyr and Trp residues of HHb, and the binding site of Sal B on HHb is located at α 1β 2 interface of HHb. Furthermore, the CD spectroscopy indicated the secondary structure of HHb is not changed in the presence of Sal B.

  3. Hemoglobin: a gas transport molecule that is hormonally regulated in the ovarian follicle in mice and humans. (United States)

    Brown, Hannah M; Anastasi, Marie R; Frank, Laura A; Kind, Karen L; Richani, Dulama; Robker, Rebecca L; Russell, Darryl L; Gilchrist, Robert B; Thompson, Jeremy G


    An increasing number of nonerythroid tissues are found to express hemoglobin mRNA and protein. Hemoglobin is a well-described gas transport molecule, especially for O2, but also for NO, CO2, and CO, and also acts as a reactive oxygen species scavenger. We previously found Hba-a1 and Hbb mRNA and protein at high levels within mouse periovulatory cumulus cells, but not in cumulus following in vitro maturation. This led us to investigate the temporal and spatial regulation in follicular cells during the periovulatory period. Cumulus-oocyte complexes were collected from equine chorionic gonadotropin/human chorionic gonadotropin-treated peripubertal SV129 female mice and collected and analyzed for gene expression and protein localization at a variety of time points over the periovulatory period. A further cohort matured in vitro with different forms of hemoglobin (ferro- and ferrihemoglobin) under different O2 atmospheric conditions (2%, 5%, and 20% O2) were subsequently fertilized in vitro and cultured to the blastocyst stage. Murine mRNA transcripts for hemoglobin were regulated by stimulation of the ovulatory cascade, in both granulosa and cumulus cells, and expression of HBA1 and HBB was highly significant in human granulosa and cumulus, but erythrocyte cell marker genes were not. Several other genes involved in hemoglobin function were similarly luteinizing hormone-regulated, including genes for heme biosynthesis. Immunohistochemistry revealed a changing localization pattern of HBA-A1 protein in murine cumulus cells and oocytes following the ovulatory signal. Significantly, no positive staining for HBA-A1 protein was observed within in vitro-matured oocytes, but, if coincubated with ferro- or ferrihemoglobin, cytoplasmic HBA-A1 was observed, similar to in vivo-derived oocytes. Addition of ferro-, but not ferrihemoglobin, had a small, positive effect on blastocyst yield, but only under either 2% or 20% O2 gas atmosphere. The identification of hemoglobin within

  4. Refractive index of solutions of human hemoglobin from the near-infrared to the ultraviolet range: Kramers-Kronig analysis. (United States)

    Sydoruk, Oleksiy; Zhernovaya, Olga; Tuchin, Valery; Douplik, Alexandre


    Because direct measurements of the refractive index of hemoglobin over a large wavelength range are challenging, indirect methods deserve particular attention. Among them, the Kramers-Kronig relations are a powerful tool often used to derive the real part of a refractive index from its imaginary part. However, previous attempts to apply the relations to solutions of human hemoglobin have been somewhat controversial, resulting in disagreement between several studies. We show that this controversy can be resolved when careful attention is paid not only to the absorption of hemoglobin but also to the dispersion of the refractive index of the nonabsorbing solvent. We present a Kramers-Kroning analysis taking both contributions into account and compare the results with the data from several studies. Good agreement with experiments is found across the visible and parts of near-infrared and ultraviolet regions. These results reinstate the use of the Kramers-Kronig relations for hemoglobin solutions and provide an additional source of information about their refractive index.

  5. Visualizing the Bohr effect in hemoglobin: neutron structure of equine cyanomethemoglobin in the R state and comparison with human deoxyhemoglobin in the T state. (United States)

    Dajnowicz, Steven; Seaver, Sean; Hanson, B Leif; Fisher, S Zoë; Langan, Paul; Kovalevsky, Andrey Y; Mueser, Timothy C


    Neutron crystallography provides direct visual evidence of the atomic positions of deuterium-exchanged H atoms, enabling the accurate determination of the protonation/deuteration state of hydrated biomolecules. Comparison of two neutron structures of hemoglobins, human deoxyhemoglobin (T state) and equine cyanomethemoglobin (R state), offers a direct observation of histidine residues that are likely to contribute to the Bohr effect. Previous studies have shown that the T-state N-terminal and C-terminal salt bridges appear to have a partial instead of a primary overall contribution. Four conserved histidine residues [αHis72(EF1), αHis103(G10), αHis89(FG1), αHis112(G19) and βHis97(FG4)] can become protonated/deuterated from the R to the T state, while two histidine residues [αHis20(B1) and βHis117(G19)] can lose a proton/deuteron. αHis103(G10), located in the α1:β1 dimer interface, appears to be a Bohr group that undergoes structural changes: in the R state it is singly protonated/deuterated and hydrogen-bonded through a water network to βAsn108(G10) and in the T state it is doubly protonated/deuterated with the network uncoupled. The very long-term H/D exchange of the amide protons identifies regions that are accessible to exchange as well as regions that are impermeable to exchange. The liganded relaxed state (R state) has comparable levels of exchange (17.1% non-exchanged) compared with the deoxy tense state (T state; 11.8% non-exchanged). Interestingly, the regions of non-exchanged protons shift from the tetramer interfaces in the T-state interface (α1:β2 and α2:β1) to the cores of the individual monomers and to the dimer interfaces (α1:β1 and α2:β2) in the R state. The comparison of regions of stability in the two states allows a visualization of the conservation of fold energy necessary for ligand binding and release.

  6. Identification and HLA-Tetramer-Validation of Human CD4(+) and CD8(+) T Cell Responses against HCMV Proteins IE1 and IE2

    DEFF Research Database (Denmark)

    Braendstrup, Peter; Mortensen, Bo Kok; Justesen, Sune Frederik Lamdahl


    tumor development. Both CD4(+) and CD8(+) T cell responses are important for long-term control of the virus, and adoptive transfer of HCMV-specific T cells has led to protection from reactivation and HCMV disease. Identification of HCMV-specific T cell epitopes has primarily focused on CD8(+) T cell......Human cytomegalovirus (HCMV) is an important human pathogen. It is a leading cause of congenital infection and a leading infectious threat to recipients of solid organ transplants as well as of allogeneic hematopoietic cell transplants. Moreover, it has recently been suggested that HCMV may promote...... responses against the pp65 phosphoprotein. In this study, we have focused on CD4(+) and CD8(+) T cell responses against the immediate early 1 and 2 proteins (IE1 and IE2). Using overlapping peptides spanning the entire IE1 and IE2 sequences, peripheral blood mononuclear cells from 16 healthy, HLA...

  7. Human hemoglobin structural and functional alterations and heme degradation upon interaction with benzene: A spectroscopic study (United States)

    Hosseinzadeh, Reza; Moosavi-Movahedi, Ali Akbar


    Here, the effect of benzene on hemoglobin structure, stability and heme prosthetic group integrity was studied by different methods. These included UV-vis absorption spectrophotometry, normal and synchronous fluorescence techniques, and differential scanning calorimetry (DSC). Our results indicated that benzene has high hemolytic potential even at low concentrations. The UV-vis spectroscopic results demonstrated that benzene altered both the globin chain and the heme prosthetic group of hemoglobin increasing met- and deoxy-Hb, while decreasing oxy-Hb. However, with increasing benzene the concentration of all species decreased due to heme destruction. The spectrophotometric results show that benzene has a high potential for penetrating the hydrophobic pocket of hemoglobin. These results were consistent with the molecular docking simulation results of benzene-hHb. Aggregation and thermal denaturation studies show that the increased benzene concentration induced hemoglobin aggregation with a decrease in stability, which is consistent with the DSC results. Conventional fluorescence spectroscopy revealed that the heme degradation species were produced in the presence of benzene. The results of constant wavelength synchronous fluorescence spectroscopy (CWSFS) indicated that at least five heme-degraded species were produced. Together, our results indicated that benzene has adverse effects on hemoglobin structure and function, and heme degradation.

  8. The initial noncovalent binding of glucose to human hemoglobin in nonenzymatic glycation. (United States)

    Clark, Shelley L D; Santin, Angela E; Bryant, Priscilla A; Holman, Rw; Rodnick, Kenneth J


    Mechanisms for nonenzymatic protein glycation have been extensively studied albeit with an emphasis at the later stages that gives rise to advanced glycation end products. No detailed investigation of the initial, noncovalent binding of d-glucose to human hemoglobin A (HbA) exists in the literature. Although anionic molecules 2,3-bisphosphoglycerate (BPG), inorganic phosphate (Pi) and HCO3(-) have been implicated in the latter stages of glycation, their involvement at the initial binding of glucose to HbA has not yet been assessed. Results from this computational study involving crystal structures of HbA predict that the transient, ring-opened glucose isomer, assumed to be critical in the later stages of glycation, is not directly involved in initial binding to the β-chain of HbA. All the five structures of glucose generated upon mutorotation will undergo reversible, competitive and slow binding at multiple amino acid residues. The ring-opened structure is most likely generated from previously bound pyranoses that undergo mutarotation while bound. BPG, Pi and HCO3(-) also reversibly bind to HbA with similar energies as glucose isomers (~3-5 kcal/mol) and share common binding sites with glucose isomers. However, there was modest amino acid residue selectivity for binding of certain anionic molecules (1-3 regions) but limited selectivity for glucose structures (≥ 7 regions). The clinical difference between average blood glucose and predicted HbA1c, and the presence of unstable HbA-glucose complexes may be more fully explained by initial noncovalent binding interactions and different concentrations of BPG, Pi and HCO3(-) in serum vs. erythrocytes.

  9. A new resveratrol tetramer from Caragana rosea

    Institute of Scientific and Technical Information of China (English)

    Guo Xun Yang; Chang Qi Hu


    In a continual effort to search for any anti-HIV agent from traditional Chinese medicine, one new resveratrol tetramer,cararosinols B, was isolated from the ethanol extract of aerial parts of Caragana rosea. Its structure was elucidated by spectroscopic analysis and comparison with known compounds.

  10. Role of the Subunits Interactions in the Conformational Transitions in Adult Human Hemoglobin: an Explicit Solvent Molecular Dynamics Study

    CERN Document Server

    Yusuff, Olaniyi K; Bussi, Giovanni; Raugei, Simone


    Hemoglobin exhibits allosteric structural changes upon ligand binding due to the dynamic interactions between the ligand binding sites, the amino acids residues and some other solutes present under physiological conditions. In the present study, the dynamical and quaternary structural changes occurring in two unligated (deoxy-) T structures, and two fully ligated (oxy-) R, R2 structures of adult human hemoglobin were investigated with molecular dynamics. It is shown that, in the sub-microsecond time scale, there is no marked difference in the global dynamics of the amino acids residues in both the oxy- and the deoxy- forms of the individual structures. In addition, the R, R2 are relatively stable and do not present quaternary conformational changes within the time scale of our simulations while the T structure is dynamically more flexible and exhibited the T\\rightarrow R quaternary conformational transition, which is propagated by the relative rotation of the residues at the {\\alpha}1{\\beta}2 and {\\alpha}2{\\b...

  11. Induction of the Epstein-Barr Virus Latent Membrane Protein 2 Antigen-specific Cytotoxic T Lymphocytes Using Human Leukocyte Antigen Tetramer-based Artificial Antigen-presenting Cells

    Institute of Scientific and Technical Information of China (English)

    Xiao-Ling LU; Zhi-Hui LIANG; Cai-E ZHANG; Sheng-Jun LU; Xiu-Fang WENG; Xiong-Wen WU


    Cytotoxic T lymphocytes (CTLs) specific for the Epstein-Barr virus (EBV) latent membrane protein 2 (LMP2) antigen are important reagents for the treatment of some EBV-associated malignancies,such as EBV-positive Hodgkin's disease and nasopharyngeal carcinoma. However, the therapeutic amount of CTLs is often hampered by the limited supply of antigen-presenting cells. To address this issue, an artificial antigen-presenting cell (aAPC) was made by coating a human leukocyte antigen (HLA)-pLMP2 tetrameric complex, anti-CD28 antibody and CD54 molecule to a cell-sized latex bead, which provided the dual signals required for T cell activation. By co-culture of the HLA-A2-LMP2 bearing aAPC and peripheral blood mononuclear cells from HLA-A2 positive healthy donors, LMP2 antigen-specific CTLs were induced and expanded in vitro. The specificity of the aAPC-induced CTLs was demonstrated by both HLA-A2-LMP2tetramer staining and cytotoxicity against HLA-A2-LMP2 bearing T2 cell, the cytotoxicity was inhibited by the anti-HLA class I antibody (W6/32). These results showed that LMP2 antigen-specific CTLs could be induced and expanded in vitro by the HLA-A2-LMP2-bearing aAPC. Thus, aAPCs coated with an HLApLMP2 complex, anti-CD28 and CD54 might be promising tools for the enrichment of LMP2-specific CTLs for adoptive immunotherapy.


    Little is known about the formation and disposition of benzene oxide (BO), the initial metabolite arising from oxidation of benzene by cytochrome P450. In this study, reactions of BO with hemoglobin (Hb) and albumin (Alb) were investigated in blood from B6C3F1 mice, F344 rats, ...

  13. Inhibition of human hemoglobin autoxidation by sodium n-dodecyl sulphate. (United States)

    Reza, Dayer Mohammad; Akbar, Moosavi-Movahedi Ali; Parviz, Norouzi; Ghourchian; Hedayat-Olah; Shahrokh, Safarian


    The effect of sodium n-dodecyl sulphate (SDS) on hemoglobin autoxidation was studied in the presence of a 100 mM phosphate buffer (pH 7.0) by different methods. These included spectrophotometry, fluorescence technique, cyclic voltametry, differential scanning calorimetry, and densitometry. Spectroscopic studies showed that SDS concentrations up to 1 mM increased deoxy-, decreases oxy-, and had no significant effect on the met- conformation of hemoglobin. Therefore, a SDS concentration up to 1 mM increased the deoxy form of hemoglobin as the folded, compact state and decreases the oxy conformation. The turbidity measurements and differential scanning calorimetry techniques indicated a more stable conformation for hemoglobin in the presence of SDS up to 1 mM. Electrochemical studies also confirmed a more difficult oxidation under these conditions. The induction of the deoxy form in the presence of SDS was confirmed by densitometry techniques. The compact structure of deoxyhemoglobin blocks the formation of met-conformation in low SDS concentrations.

  14. Engineering the oxygen sensing regulation results in an enhanced recombinant human hemoglobin production by Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Martínez, José L.; Liu, Lifang; Petranovic, Dina


    Efficient production of appropriate oxygen carriers for transfusions (blood substitutes or artificial blood) has been pursued for many decades, and to date several strategies have been used, from synthetic polymers to cell-free hemoglobin carriers. The recent advances in the field of metabolic...

  15. Bohr effect of human hemoglobin A: magnitude of negative contributions determined by the equilibrium between two tertiary structures. (United States)

    Okonjo, Kehinde O; Olatunde, Abimbola M; Fodeke, Adedayo A; Babalola, J Oyebamiji


    We have measured the affinity of the CysF9[93]β sulfhydryl group of human deoxyhemoglobin and oxyhemoglobin for 5,5'-dithiobis(2-nitrobenzoate), DTNB, between pH ≈5.6 and 9 in order to understand the basis of the reported reduction of the Bohr effect induced by chemical modification of the sulfhydryl. We analyzed the results quantitatively on the basis of published data indicating that the sulfhydryl exists in two conformations that are coupled to the transition between two tertiary structures of hemoglobin in dynamic equilibrium. Our analyses show that the ionizable groups linked to the DTNB reaction have lower pKas of ionization in deoxyhemoglobin compared to oxyhemoglobin. So these ionizable groups should make negative contributions to the Bohr effect. We identify these groups as HisNA2[2]β, HisEF1[77]β and HisH21[143]β. We provide explanations for the finding that hemoglobin, chemically modified at CysF9[93]β, has a lower Bohr effect and a higher oxygen affinity than unmodified hemoglobin.

  16. Biophysical characterisation of neuroglobin of the icefish, a natural knockout for hemoglobin and myoglobin. Comparison with human neuroglobin.

    Directory of Open Access Journals (Sweden)

    Daniela Giordano

    Full Text Available The Antarctic icefish Chaenocephalus aceratus lacks the globins common to most vertebrates, hemoglobin and myoglobin, but has retained neuroglobin in the brain. This conserved globin has been cloned, over-expressed and purified. To highlight similarities and differences, the structural features of the neuroglobin of this colourless-blooded fish were compared with those of the well characterised human neuroglobin as well as with the neuroglobin from the retina of the red blooded, hemoglobin and myoglobin-containing, closely related Antarctic notothenioid Dissostichus mawsoni. A detailed structural and functional analysis of the two Antarctic fish neuroglobins was carried out by UV-visible and Resonance Raman spectroscopies, molecular dynamics simulations and laser-flash photolysis. Similar to the human protein, Antarctic fish neuroglobins can reversibly bind oxygen and CO in the Fe(2+ form, and show six-coordination by distal His in the absence of exogenous ligands. A very large and structured internal cavity, with discrete docking sites, was identified in the modelled three-dimensional structures of the Antarctic neuroglobins. Estimate of the free-energy barriers from laser-flash photolysis and Implicit Ligand Sampling showed that the cavities are accessible from the solvent in both proteins.Comparison of structural and functional properties suggests that the two Antarctic fish neuroglobins most likely preserved and possibly improved the function recently proposed for human neuroglobin in ligand multichemistry. Despite subtle differences, the adaptation of Antarctic fish neuroglobins does not seem to parallel the dramatic adaptation of the oxygen carrying globins, hemoglobin and myoglobin, in the same organisms.

  17. Upstream promoter mutation associated with a modest elevation of fetal hemoglobin expression in human adults. (United States)

    Gilman, J G; Mishima, N; Wen, X J; Kutlar, F; Huisman, T H


    In hereditary persistence of fetal hemoglobin, Hb F (alpha 2 gamma 2) is elevated after birth. Screening of sickle cell patients has revealed a family with elevated Hb F and high A gamma values. The propositus was a sickle cell patient with approximately 25% Hb F and 68.4% A gamma. He was heterozygous for the Benin (#19) and Mor beta S haplotypes. Five AS relatives with the Mor haplotype had 2.5% +/- 0.9% fetal hemoglobin and 92.8% +/- 2.8% A gamma, whereas two with the Benin haplotype had normal fetal hemoglobin (0.5%). The Mor haplotype is thus associated with the elevated Hb F in this family. The 13-kilobase (kb) Bg/II fragment containing the G gamma and A gamma genes of the Mor haplotype was cloned, and the G gamma and A gamma promoters sequenced from -383 to beyond the Cap sites. The Mor G gamma gene was normal, but the A gamma gene had a unique C----T mutation at -202. A different mutation at -202 of G gamma (C----G) was previously detected by other researchers in association with considerably higher Hb F in AS cases (15% to 25%). These data suggest either that -202 mutations affect the G gamma and A gamma promoters differently or that different nucleotide substitutions at -202 have divergent effects. Alternatively, additional unknown mutations could cause the differences in gene expression.

  18. Hemoglobin Philly (β35 tyrosine→phenylalanine): studies in the molecular pathology of hemoglobin (United States)

    Rieder, Ronald F.; Oski, Frank A.; Clegg, J. B.


    An abnormal unstable hemoglobin, hemoglobin Philly, was found in three members of a family, each of whom had evidence of a chronic hemolytic state. The presence of the mutant protein was suggested by the rapid appearance of inclusion bodies upon incubation of erythrocytes with brilliant cresyl blue and by the increased heat precipitability of the hemoglobin. However, no abnormal hemoglobin could be demonstrated by electrophoresis or column chromatography. Sulfhydryl titration of the hemolysates with p-mercuribenzoate indicated that there was an average of four reactive sulfhydryl groups per hemoglobin molecule instead of the usual two. The total number of hemoglobin sulfhydryl groups was normal; six groups were measured when denatured globin was reacted with 5,5′-dithiobis[2-nitrobenzoic acid]. This indicated that the increased sulfhydryl reactivity was due to an increased availability to p-mercuribenzoate of the usually unreactive hemoglobin cysteines at β112 and α104. After treatment for ½ hr with 4-5 moles of p-mercuribenzoate per mole of hemoglobin, electrophoresis revealed that 30-35% of the hemoglobin had been dissociated into α- and β-chains. Normal hemolysates revealed negligible splitting after 72 hr of similar treatment. The α- and β-chains of hemoglobin Philly were separated from the unsplit hemoglobin A by carboxymethyl cellulose chromatography. Fingerprint and amino acid analyses revealed that tyrosine β35 was replaced by phenylalanine. In hemoglobin Philly there is loss of the normal hydrogen bond between the tyrosine hydroxyl group and the carboxyl group of aspartic acid α126 at the α1β1 contact. This shifts the equilibrium from hemoglobin tetramers toward monomers, exposing the β112 and α104 cysteines. In the cell, precipitation of the unstable monomers may contribute to erythrocyte destruction. Images PMID:5822575

  19. A Genetic Variant Ameliorates β-Thalassemia Severity by Epigenetic-Mediated Elevation of Human Fetal Hemoglobin Expression. (United States)

    Chen, Diyu; Zuo, Yangjin; Zhang, Xinhua; Ye, Yuhua; Bao, Xiuqin; Huang, Haiyan; Tepakhan, Wanicha; Wang, Lijuan; Ju, Junyi; Chen, Guangfu; Zheng, Mincui; Liu, Dun; Huang, Shuodan; Zong, Lu; Li, Changgang; Chen, Yajun; Zheng, Chenguang; Shi, Lihong; Zhao, Quan; Wu, Qiang; Fucharoen, Supan; Zhao, Cunyou; Xu, Xiangmin


    A delayed fetal-to-adult hemoglobin (Hb) switch ameliorates the severity of β-thalassemia and sickle cell disease. The molecular mechanism underlying the epigenetic dysregulation of the switch is unclear. To explore the potential cis-variants responsible for the Hb switching, we systematically analyzed an 80-kb region spanning the β-globin cluster using capture-based next-generation sequencing of 1142 Chinese β-thalassemia persons and identified 31 fetal hemoglobin (HbF)-associated haplotypes of the selected 28 tag regulatory single-nucleotide polymorphisms (rSNPs) in seven linkage disequilibrium (LD) blocks. A Ly1 antibody reactive (LYAR)-binding motif disruptive rSNP rs368698783 (G/A) from LD block 5 in the proximal promoter of hemoglobin subunit gamma 1 (HBG1) was found to be a significant predictor for β-thalassemia clinical severity by epigenetic-mediated variant-dependent HbF elevation. We found this rSNP accounted for 41.6% of β-hemoglobinopathy individuals as an ameliorating factor in a total of 2,738 individuals from southern China and Thailand. We uncovered that the minor allele of the rSNP triggers the attenuation of LYAR and two repressive epigenetic regulators DNA methyltransferase 3 alpha (DNMT3A) and protein arginine methyltransferase 5 (PRMT5) from the HBG promoters, mediating allele-biased γ-globin elevation by facilitating demethylation of HBG core promoter CpG sites in erythroid progenitor cells from β-thalassemia persons. The present study demonstrates that this common rSNP in the proximal (A)γ-promoter is a major genetic modifier capable of ameliorating the severity of thalassemia major through the epigenetic-mediated regulation of the delayed fetal-to-adult Hb switch and provides potential targets for the treatment of β-hemoglobinopathy. Copyright © 2017 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  20. Hemoglobin electrophoresis (United States)

    ... 12. Read More A1C test Anemia Hemoglobin Hemolytic anemia Sickle cell anemia Thalassemia Review Date 1/31/2016 Updated by: ... Anemia Blood Count Tests Blood Disorders Newborn Screening Sickle Cell Anemia Browse the Encyclopedia A.D.A.M., Inc. ...

  1. Fish hemoglobins

    Directory of Open Access Journals (Sweden)

    P.C. de Souza


    Full Text Available Vertebrate hemoglobin, contained in erythrocytes, is a globular protein with a quaternary structure composed of 4 globin chains (2 alpha and 2 beta and a prosthetic group named heme bound to each one. Having myoglobin as an ancestor, hemoglobin acquired the capacity to respond to chemical stimuli that modulate its function according to tissue requirements for oxygen. Fish are generally submitted to spatial and temporal O2 variations and have developed anatomical, physiological and biochemical strategies to adapt to the changing environmental gas availability. Structurally, most fish hemoglobins are tetrameric; however, those from some species such as lamprey and hagfish dissociate, being monomeric when oxygenated and oligomeric when deoxygenated. Fish blood frequently possesses several hemoglobins; the primary origin of this finding lies in the polymorphism that occurs in the globin loci, an aspect that may occasionally confer advantages to its carriers or even be a harmless evolutionary remnant. On the other hand, the functional properties exhibit different behaviors, ranging from a total absence of responses to allosteric regulation to drastic ones, such as the Root effect.

  2. An Alternative to the Human Hemoglobin Test in the Investigation of Bloodstains Treated with Active Oxygen: The Human Glycophorin A Test

    Directory of Open Access Journals (Sweden)

    Ana Castelló


    Full Text Available In criminal investigations, there are three stages involved when studying bloodstains: search and orientation, confirmation, and individualization. Confirmatory tests have two aims: to show that the stain contains a human biological fluid and to confirm the type of biological fluid. The need to determine the nature of the evidence is reflected in the latest bibliography, where the possibility of employing mRNA and miRNA markers for this purpose is proposed. While these new proposals are being investigated, the kits for determining human hemoglobin currently provide a simple solution for resolving this issue. With these kits, the possibility of obtaining false positives and false negatives is well known. However, recently, a new problem has been detected. This involves the interference caused by new cleaning products that contain sodium percarbonate (or active oxygen when determining human hemoglobin. With the aim to resolve this problem, this work studied the ability of the human glycophorin A test to determine human blood in samples that have been treated with active oxygen. Our results show that the human glycophorin A test has a greater resistance to the destructive effect of the new detergents containing active oxygen; consequently, it provides an alternative to be taken into consideration in the confirmatory diagnoses of bloodstains.

  3. Assessing the relative stabilities of engineered hemoglobins using electrospray mass spectrometry. (United States)

    Apostol, I


    An ion trap mass spectrometer equipped with an electrospray source was used to examine the relative thermodynamic stabilities of various hemoglobins with respect to both tetramer dissociation and hemin dissociation. The results demonstrated that the stability of hemoglobin molecules can be differentiated by the amount of applied collision-induced dissociation (CID) energy necessary to break up the intact tetramer into its constituent globins. The stability of the intact tetramer was affected by single mutations in the beta-globins. The stabilities of the constituent hologlobins were assessed via trap CID of selected ions. The results demonstrated the importance of the contributions of the hologlobin components to the stability of the intact tetramer. Genetic fusion of two alpha-globins, through the introduction of a single glycine residue between the C-terminus of one alpha-chain and the N-terminus of the second, significantly increased the stability of the hemoglobin pseudo-tetramer. Chemical crosslinking of the beta-globins in addition to genetic fusion of alpha-globins further stabilized the hemoglobin molecule. A dihemoglobin molecule produced by the genetic fusion of two di-alpha-globins with a flexible linker demonstrated a decreased stability relative to the corresponding monohemoglobin.

  4. Derivation of the human induced pluripotent stem cell line MUi017-A from a patient with homozygous Hemoglobin Constant Spring

    Directory of Open Access Journals (Sweden)

    Wasinee Wongkummool


    Full Text Available Hemoglobin Constant Spring (HbCS, HBA2: c.427T>C is a common nondeletional α-thalassemia resulting from a nucleotide substitution at the termination codon of the HBA2 gene. Homozygosity for HbCS is characterized with mild anemia, jaundice, and splenomegaly. In this study, the human induced pluripotent stem cell line MUi017-A was successfully generated from peripheral blood CD34+ hematopoietic progenitors of a 52 year old female with homozygous HbCS. The MUi017-A cell line exhibited embryonic stem cell characteristics with consistent expression of specific pluripotency markers and the capability of differentiating into the three germ layers. The cell line may be used for the disease modeling.

  5. Theoretical study of interactions between human adult hemoglobin and acetate ion by polarizable force field and fragmentation quantum chemistry methods

    Institute of Scientific and Technical Information of China (English)

    YAN XiuFen; JIANG Nan; MA Jing


    A series of theoretical approaches,including conventional FF03 and FF03-based polarization model,as well as the generalized energy-based fragmentation (GEBF) quantum chemistry method,have been applied to investigate the interactions between acetate ion (CH_3COO~-) and the α-subunit of human adult hemoglobin (designated as Hb-α) at four binding sites (Lys16,Lys90,Arg92,and Lys127),respectively.The FF03-based polarizable force fields show that the interaction energies between the CH_3COO~-group and Hb-α follow the trend of Arg92>Lys127>Lys90>Lys16.The complexation of CH_3COO~-with Hb-α is governed by the long-range electrostatic interactions and steric effect.

  6. Theoretical study of interactions between human adult hemoglobin and acetate ion by polarizable force field and fragmentation quantum chemistry methods

    Institute of Scientific and Technical Information of China (English)


    A series of theoretical approaches,including conventional FF03 and FF03-based polarization model,as well as the generalized energy-based fragmentation(GEBF) quantum chemistry method,have been applied to investigate the interactions between acetate ion(CH3COO-) and the α-subunit of human adult hemoglobin(designated as Hb-α) at four binding sites(Lys16,Lys90,Arg92,and Lys127),respectively.The FF03-based polarizable force fields show that the interaction energies between the CH3COO-group and Hb-α follow the trend of Arg92>Lys127>Lys90>Lys16.The complexation of CH3COO-with Hb-α is governed by the long-range electrostatic interactions and steric effect.

  7. Hemoglobin C disease (United States)

    Clinical hemoglobin C ... Hemoglobin C is an abnormal type of hemoglobin, the protein in red blood cells that carries oxygen. It is ... Americans. You are more likely to have hemoglobin C disease if someone in your family has had ...

  8. Palladium-Catalyzed alpha-Arylation of Tetramic Acids

    DEFF Research Database (Denmark)

    Storgaard, Morten; Dorwald, F. Z.; Peschke, B.;


    A mild, racemization-free, palladium-Catalyzed alpha-arylation of tetramic acids (2,4-pyrrolidinediones) has been developed. Various amino acid-derived tetramic acids were cleanly arylated by treatment with 2 mol % of Pd(OAc)(2), 4 mol % of a sterically demanding biaryl phosphine, 2.3 equiv of K2CO...

  9. Resveratrol Tetramers from the Roots ofAmpelopsis sinica

    Institute of Scientific and Technical Information of China (English)


    A new resveratrol tetramer, sinicin A was isolated from the roots ofAmpelopsis sinica,with four known tetramers: vitisin A, cis-vitisin B, ampelopsin H and hopeaphenol. The structure and stereochemistry of sinicin A have been established on the basis of 1D and 2D NMR spectroscopic techniques.

  10. MicroRNA-15a and -16-1 act via MYB to elevate fetal hemoglobin expression in human trisomy 13. (United States)

    Sankaran, Vijay G; Menne, Tobias F; Šćepanović, Danilo; Vergilio, Jo-Anne; Ji, Peng; Kim, Jinkuk; Thiru, Prathapan; Orkin, Stuart H; Lander, Eric S; Lodish, Harvey F


    Many human aneuploidy syndromes have unique phenotypic consequences, but in most instances it is unclear whether these phenotypes are attributable to alterations in the dosage of specific genes. In human trisomy 13, there is delayed switching and persistence of fetal hemoglobin (HbF) and elevation of embryonic hemoglobin in newborns. Using partial trisomy cases, we mapped this trait to chromosomal band 13q14; by examining the genes in this region, two microRNAs, miR-15a and -16-1, appear as top candidates for the elevated HbF levels. Indeed, increased expression of these microRNAs in primary human erythroid progenitor cells results in elevated fetal and embryonic hemoglobin gene expression. Moreover, we show that a direct target of these microRNAs, MYB, plays an important role in silencing the fetal and embryonic hemoglobin genes. Thus we demonstrate how the developmental regulation of a clinically important human trait can be better understood through the genetic and functional study of aneuploidy syndromes and suggest that miR-15a, -16-1, and MYB may be important therapeutic targets to increase HbF levels in patients with sickle cell disease and β-thalassemia.

  11. Hemoglobin is a co-factor of human trypanosome lytic factor

    DEFF Research Database (Denmark)

    Widener, Justin; Nielsen, Marianne Jensby; Shiflett, April


    by increasing the affinity of TLF for its receptor, and by inducing Fenton chemistry within the trypanosome lysosome. These findings suggest that TLF in uninfected humans may be inactive against T. b. brucei prior to initiation of infection. We propose that infection of humans by T. b. brucei causes hemolysis...

  12. Mass Spectrometric Analysis of Glyoxal and Methylglyoxal-Induced Modifications in Human Hemoglobin from Poorly Controlled Type 2 Diabetes Mellitus Patients. (United States)

    Chen, Hauh-Jyun Candy; Chen, Yu-Chin; Hsiao, Chiung-Fong; Chen, Pin-Fan


    Glyoxal and methylglyoxal are oxoaldehydes derived from the degradation of glucose-protein conjugates and from lipid peroxidation, and they are also present in the environment. This study investigated the site-specific reaction of glyoxal and methylglyoxal with the amino acid residues on human hemoglobin using a shot-gun proteomic approach with nanoflow liquid chromatography/nanospray ionization tandem mass spectrometry (nanoLC-NSI/MS/MS). In human hemoglobin incubated with glyoxal, modification on 8 different sites, including lysine residues at α-Lys-11, α-Lys-16, α-Lys-56, β-Lys-17, β-Lys-66, β-Lys-144, and arginine residues at α-Arg-92 and β-Arg-30, was observed using a data-dependent scan. In methylglyoxal-treated hemoglobin, there were specific residues, namely, α-Arg-92, β-Lys-66, β-Arg-30, and β-Lys-144, forming carboxyethylation as well as the dehydrated product hydroimidazolone at α-Arg-92 and β-Arg-30. These lysine and arginine modifications were confirmed by accurate mass measurement and the MS(2) and MS(3) spectra. The most intensive signal of each modified peptide was used as the precursor ion to perform the product ion scan. The relative extent of modifications was semiquantified simultaneously relative to the native reference peptide by nanoLC-NSI/MS/MS under the selected reaction monitoring (SRM) mode. The extent of these modifications increased dose-dependently with increasing concentrations of glyoxal or methylglyoxal. Six out of the eight modifications induced by glyoxal and three out of the six modifications induced by methylglyoxal were detected in hemoglobin freshly isolated from human blood samples. The relative extent of modification of these post-translational modifications was quantified in poorly controlled type 2 diabetes mellitus patients (n = 20) and in nondiabetic control subjects (n = 21). The results show that the carboxymethylated peptides at α-Lys-16, α-Arg-92, β-Lys-17, β-Lys-66, and the peptide at α-Arg-92

  13. The interaction of actinide and lanthanide ions with hemoglobin and its relevance to human and environmental toxicology

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Amit, E-mail: [Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Ali, Manjoor [Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Ningthoujam, Raghumani S. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Gaikwad, Pallavi [Department of Zoology, Savitribai Phule Pune University, Pune 411 007, Mumbai (India); Kumar, Mukesh [Solid State, Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Nath, Bimalendu B. [Department of Zoology, Savitribai Phule Pune University, Pune 411 007, Mumbai (India); Pandey, Badri N. [Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)


    Highlights: • The sites of Ln and An interaction in Hb depend upon their charge-to-ionic-radii ratio. • Th(IV), Ce(IV) and U(VI) altered structure and oxygen-binding of Hb. • Spectroscopic studies determined binding characteristics of actinides. • Metal–Hb interaction was tested in an environmentally-important aquatic midge, Chironomus. - Abstract: Due to increasing use of lanthanides/actinides in nuclear and civil applications, understanding the impact of these metal ions on human health and environment is a growing concern. Hemoglobin (Hb), which occurs in all the kingdom of living organism, is the most abundant protein in human blood. In present study, effect of lanthanides and actinides [thorium: Th(IV), uranium: U(VI), lanthanum: La(III), cerium: Ce(III) and (IV)] on the structure and function of Hb has been investigated. Results showed that these metal ions, except Ce(IV) interacted with carbonyl and amide groups of Hb, which resulted in the loss of its alpha-helix conformation. However, beyond 75 μM, these ions affected heme moiety. Metal–heme interaction was found to affect oxygen-binding of Hb, which seems to be governed by their closeness with the charge-to-ionic-radius ratio of iron(III). Consistently, Ce(IV) being closest to iron(III), exhibited a greater effect on heme. Binding constant and binding stoichiometry of Th(IV) were higher than that of U(VI). Experiments using aquatic midge Chironomus (possessing human homologous Hb) and human blood, further validated metal–Hb interaction and associated toxicity. Thus, present study provides a biochemical basis to understand the actinide/lanthanide-induced interference in heme, which may have significant implications for the medical and environmental management of lanthanides/actinides toxicity.

  14. Mutations in the paralogous human α-globin genes yielding identical hemoglobin variants

    NARCIS (Netherlands)

    K. Moradkhani (Kamran); C. Prehu (Claude); J. Old (John); S. Henderson (Shirley); V. Balamitsa (Vera); H-Y. Luo; M-C. Poon (Man-Chiu); D.H. Chui (David); H. Wajcman (Henri); G.P. Patrinos (George)


    textabstractThe human α-globin genes are paralogues, sharing a high degree of DNA sequence similarity and producing an identical α-globin chain. Over half of the α-globin structural variants reported to date are only characterized at the amino acid level. It is likely that a fraction of these varian

  15. Hemoglobin is a co-factor of human trypanosome lytic factor.

    Directory of Open Access Journals (Sweden)

    Justin Widener


    Full Text Available Trypanosome lytic factor (TLF is a high-density lipoprotein (HDL subclass providing innate protection to humans against infection by the protozoan parasite Trypanosoma brucei brucei. Two primate-specific plasma proteins, haptoglobin-related protein (Hpr and apolipoprotein L-1 (ApoL-1, have been proposed to kill T. b. brucei both singularly or when co-assembled into the same HDL. To better understand the mechanism of T. b. brucei killing by TLF, the protein composition of TLF was investigated using a gentle immunoaffinity purification technique that avoids the loss of weakly associated proteins. HDL particles recovered by immunoaffinity absorption, with either anti-Hpr or anti-ApoL-1, were identical in protein composition and specific activity for T. b. brucei killing. Here, we show that TLF-bound Hpr strongly binds Hb and that addition of Hb stimulates TLF killing of T. b. brucei by increasing the affinity of TLF for its receptor, and by inducing Fenton chemistry within the trypanosome lysosome. These findings suggest that TLF in uninfected humans may be inactive against T. b. brucei prior to initiation of infection. We propose that infection of humans by T. b. brucei causes hemolysis that triggers the activation of TLF by the formation of Hpr-Hb complexes, leading to enhanced binding, trypanolytic activity, and clearance of parasites.

  16. A critical study on the interactions of hesperitin with human hemoglobin: Fluorescence spectroscopic and molecular modeling approach

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, Sandipan [Saroj Mohan Institute of Technology, Hooghly (India); Chaudhuri, Sudip; Pahari, Biswapathik [Biophysics Division, Saha Institute of Nuclear Physics, Kolkata 700064 (India); Taylor, Jasmine [Chemistry Department, Tougaloo College, Tougaloo, MS 39174 (United States); Sengupta, Pradeep K. [Biophysics Division, Saha Institute of Nuclear Physics, Kolkata 700064 (India); Sengupta, Bidisha, E-mail: [Chemistry Department, Tougaloo College, Tougaloo, MS 39174 (United States)


    Hesperitin, a ubiquitous bioactive flavonoid abundant in citrus fruits is known to possess antioxidant, anti-carcinogenic, hypolipidemic, vasoprotective and other important therapeutic properties. Here we have explored the interactions of hesperitin with normal human hemoglobin (HbA), using steady state and time resolved fluorescence spectroscopy, far UV circular dicroism (CD) spectroscopy, combined with molecular modeling computations. Specific interaction of the flavonoid with HbA is confirmed from flavonoid-induced static quenching which is evident from steady state fluorescence as well as lifetime data. Both temperature dependent fluorescence measurements and molecular docking studies reveal that apart from hydrogen bonding and van der Waals interactions, electrostatic interactions also play crucial role in hesperitin-HbA interactions. Furthermore, electrostatic surface potential calculations indicate that the hesperitin binding site in HbA is intensely positive due to the presence of several lysine and histidine residues. - Highlights: Black-Right-Pointing-Pointer Absorption spectra of hesperitin bound HbA indicates ground state complex formation. Black-Right-Pointing-Pointer Binding induces static quenching of intrinsic fluorescence of the tryptophan of HbA. Black-Right-Pointing-Pointer Molecular docking and electrostatic surface potential calculations were performed. Black-Right-Pointing-Pointer Contrasting binding modes of hesperitin compared to other flavonoids were observed.

  17. Glycidol exposure evaluation of humans who have ingested diacylglycerol oil containing glycidol fatty acid esters using hemoglobin adducts. (United States)

    Honda, Hiroshi; Fujii, Kenkichi; Yamaguchi, Tohru; Ikeda, Naohiro; Nishiyama, Naohiro; Kasamatsu, Toshio


    Glycidol fatty acid esters (GEs) have been found as impurities in refined edible oils including diacylglycerol (DAG) oil, and concerns of possible exposure to glycidol (G), a known animal carcinogen, during digestion have been raised. We previously measured N-(2,3-dihydroxy-propyl)valine (diHOPrVal), a G hemoglobin adduct, for DAG oil exposed and non-exposed groups and showed there was no significant difference between them. In the present study, we conducted an additional analysis to verify the outcome of the previous report. The first experiment was designed as a matched case-control study to adjust variables with an increased sample size. The average levels of diHOPrVal were 6.9 pmol/g-globin (95%CI: 4.9-9.0) for 14 DAG oil exposed subjects and 7.3 pmol/g-globin (95%CI: 6.1-8.5) for 42 non-exposed volunteers, and no significant difference in levels was found between the two groups. In a second experiment, we compared the adduct levels of 12 DAG oil exposed subjects before and after discontinuing use of DAG oil, and found there was no significant change in diHOPrVal levels (from 7.1±1.1 to 7.5±1.4 pmol/g-globin). These results suggest that there was no increased exposure to G for humans who ingested DAG oil daily, although the evaluated population was limited.

  18. Measurement of glycidol hemoglobin adducts in humans who ingest edible oil containing small amounts of glycidol fatty acid esters. (United States)

    Honda, Hiroshi; Onishi, Masayuki; Fujii, Kenkichi; Ikeda, Naohiro; Yamaguchi, Tohru; Fujimori, Taketoshi; Nishiyama, Naohiro; Kasamatsu, Toshio


    Hemoglobin (Hb) adducts are frequently used to address and/or monitor exposure to reactive chemicals. Glycidol (G), a known animal carcinogen, has been reported to form Hb adducts. Here, we measure G adduct levels in humans who daily ingest DAG oil, an edible oil consisting mainly of diacylglycerol. Since DAG oil contains a small amount of glycidol fatty acid esters (GEs), possible exposure to G released from GEs has been raised as a possible concern. For measurement of Hb adducts, we employed the N-alkyl Edman method reported by Landin et al. (1996) using gas chromatography-tandem mass spectrometry with minor modifications to detect G-Hb adducts as N-(2,3-dihydroxy-propyl)valine (diHOPrVal). Blood samples were collected from 7 DAG oil users and 6 non-users, and then G-Hb adduct levels were measured. G-Hb adducts were detected in all samples. The average level of diHOPrVal was 3.5±1.9pmol/g globin in the DAG oil users and 7.1±3.1pmol/g globin in the non-users. We conclude that there is no increased exposure to G in individuals who daily ingest DAG oil.

  19. Separation of human hemoglobins by DEAE-cellulose chromatography using glycine-KCN-NaC1 developers. (United States)

    Abraham, E C; Reese, A; Stallings, M; Huisman, T H

    This chromatographic procedure uses DEAE-cellulose as ion exchanger and glycine-KCN-NaC1 solutions as developers. Blood samples from several adults and newborn infants with alpha, beta, delta, or gamma chains variants have been analysed. The hemoglobins are eluted as compact and symmetrical zones, and the separation of many hemoglobin types is greatly improved. The procedure is relatively fast, simple, and inexpensive.

  20. Universal bosonic tetramers of dimer-atom-atom structure


    Deltuva, A.


    Unstable four-boson states having an approximate dimer-atom-atom structure are studied using momentum-space integral equations for the four-particle transition operators. For a given Efimov trimer the universal properties of the lowest associated tetramer are determined. The impact of this tetramer on the atom-trimer and dimer-dimer collisions is analyzed. The reliability of the three-body dimer-atom-atom model is studied.

  1. 21 CFR 864.5620 - Automated hemoglobin system. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Automated hemoglobin system. 864.5620 Section 864....5620 Automated hemoglobin system. (a) Identification. An automated hemoglobin system is a fully... hemoglobin content of human blood. (b) Classification. Class II (performance standards)....

  2. Therapeutic hemoglobin levels after gene transfer in β-thalassemia mice and in hematopoietic cells of β-thalassemia and sickle cells disease patients.

    Directory of Open Access Journals (Sweden)

    Laura Breda

    Full Text Available Preclinical and clinical studies demonstrate the feasibility of treating β-thalassemia and Sickle Cell Disease (SCD by lentiviral-mediated transfer of the human β-globin gene. However, previous studies have not addressed whether the ability of lentiviral vectors to increase hemoglobin synthesis might vary in different patients.We generated lentiviral vectors carrying the human β-globin gene with and without an ankyrin insulator and compared their ability to induce hemoglobin synthesis in vitro and in thalassemic mice. We found that insertion of an ankyrin insulator leads to higher, potentially therapeutic levels of human β-globin through a novel mechanism that links the rate of transcription of the transgenic β-globin mRNA during erythroid differentiation with polysomal binding and efficient translation, as reported here for the first time. We also established a preclinical assay to test the ability of this novel vector to synthesize adult hemoglobin in erythroid precursors and in CD34(+ cells isolated from patients affected by β-thalassemia and SCD. Among the thalassemic patients, we identified a subset of specimens in which hemoglobin production can be achieved using fewer copies of the vector integrated than in others. In SCD specimens the treatment with AnkT9W ameliorates erythropoiesis by increasing adult hemoglobin (Hb A and concurrently reducing the sickling tetramer (Hb S.Our results suggest two major findings. First, we discovered that for the purpose of expressing the β-globin gene the ankyrin element is particularly suitable. Second, our analysis of a large group of specimens from β-thalassemic and SCD patients indicates that clinical trials could benefit from a simple test to predict the relationship between the number of vector copies integrated and the total amount of hemoglobin produced in the erythroid cells of prospective patients. This approach would provide vital information to select the best candidates for these

  3. Therapeutic hemoglobin levels after gene transfer in β-thalassemia mice and in hematopoietic cells of β-thalassemia and sickle cells disease patients. (United States)

    Breda, Laura; Casu, Carla; Gardenghi, Sara; Bianchi, Nicoletta; Cartegni, Luca; Narla, Mohandas; Yazdanbakhsh, Karina; Musso, Marco; Manwani, Deepa; Little, Jane; Gardner, Lawrence B; Kleinert, Dorothy A; Prus, Eugenia; Fibach, Eitan; Grady, Robert W; Giardina, Patricia J; Gambari, Roberto; Rivella, Stefano


    Preclinical and clinical studies demonstrate the feasibility of treating β-thalassemia and Sickle Cell Disease (SCD) by lentiviral-mediated transfer of the human β-globin gene. However, previous studies have not addressed whether the ability of lentiviral vectors to increase hemoglobin synthesis might vary in different patients.We generated lentiviral vectors carrying the human β-globin gene with and without an ankyrin insulator and compared their ability to induce hemoglobin synthesis in vitro and in thalassemic mice. We found that insertion of an ankyrin insulator leads to higher, potentially therapeutic levels of human β-globin through a novel mechanism that links the rate of transcription of the transgenic β-globin mRNA during erythroid differentiation with polysomal binding and efficient translation, as reported here for the first time. We also established a preclinical assay to test the ability of this novel vector to synthesize adult hemoglobin in erythroid precursors and in CD34(+) cells isolated from patients affected by β-thalassemia and SCD. Among the thalassemic patients, we identified a subset of specimens in which hemoglobin production can be achieved using fewer copies of the vector integrated than in others. In SCD specimens the treatment with AnkT9W ameliorates erythropoiesis by increasing adult hemoglobin (Hb A) and concurrently reducing the sickling tetramer (Hb S).Our results suggest two major findings. First, we discovered that for the purpose of expressing the β-globin gene the ankyrin element is particularly suitable. Second, our analysis of a large group of specimens from β-thalassemic and SCD patients indicates that clinical trials could benefit from a simple test to predict the relationship between the number of vector copies integrated and the total amount of hemoglobin produced in the erythroid cells of prospective patients. This approach would provide vital information to select the best candidates for these clinical trials

  4. Feasibility of iodine-125 labeled anti-human hemoglobin antibody in the detection of bleeding sites from the large bowel-A preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Prado, G.L.M.; Abe, Yoshinao; Saito, Hiroshi [Hirosaki Univ., Aomori (Japan). School of Medicine; Nakamura, Kayoko


    A monoclonal anti-human hemoglobin antibody that cross-reacts with mouse hemoglobin was labeled with Iodine-125 through the Chloramine-T method. The labeled antibody was used in an attempt to recognize bleeding sites from the large bowel in a mouse model, through a non-invasive enema-like study. In vitro experiments after double column chromatography of the labeled antibody and 10% trichloroacetic acid conjugation revealed that about 80% of the radioactivity was incorporated into protein. Inhibition assay containing could (non-radiolabeled) antibody showed that Iodine-125 radiolabeled antibody preserved its immunoreactivity. Autoradiographs exquisitely demonstrated accumulation of isotope in the corresponding intestinal bleeding areas. These findings suggest that this method can be useful for scintigraphic localization of bleeding sites in the large bowel. (author)

  5. Detection of total and A1c-glycosylated hemoglobin in human whole blood using sandwich immunoassays on polydimethylsiloxane-based antibody microarrays. (United States)

    Chen, Huang-Han; Wu, Chih-Hsing; Tsai, Mei-Ling; Huang, Yi-Jing; Chen, Shu-Hui


    The percentage of glycosylated hemoglobin A1c (%GHbA1c) in human whole blood indicates the average plasma glucose concentration over a prolonged period of time and is used to diagnose diabetes. However, detecting GHbA1c in the whole blood using immunoassays has limited detection sensitivity due to its low percentage in total hemoglobin (tHb) and interference from various glycan moieties in the sample. We have developed a sandwich immunoassay using an antibody microarray on a polydimethylsiloxane (PDMS) substrate modified with fluorinated compounds to detect tHb and glycosylated hemoglobin A1c (GHbA1c) in human whole blood without sample pretreatment. A polyclonal antibody against hemoglobin (Hb) immobilized on PDMS is used as a common capture probe to enrich all forms of Hb followed by detection via monoclonal anti-Hb and specific monoclonal anti-GHbA1c antibodies for tHb and GHbA1c detection, respectively. This method prevents the use of glycan binding molecules and dramatically reduces the background interference, yielding a detection limit of 3.58 ng/mL for tHb and 0.20 ng/mL for GHbA1c. The fluorinated modification on PDMS is superior to the glass substrate and eliminates the need for the blocking step which is required in commercial enzyme linked immunosorbent assay (ELISA) kits. Moreover, the detection sensitivity for GHbA1c is 4-5 orders of magnitude higher, but the required sample amount is 25 times less than the commercial method. On the basis of patient sample data, a good linear correlation between %GHbA1c values determined by our method and the certified high performance liquid chromatography (HPLC) standard method is shown with R(2) > 0.98, indicating the great promise of the developed method for clinical applications.

  6. Improvements in the HbVar database of human hemoglobin variants and thalassemia mutations for population and sequence variation studies.

    NARCIS (Netherlands)

    G.P. Patrinos (George); B. Giardine (Belinda); C. Riemer (Cathy); W. Miller (Webb); D.H. Chui (David); N.P. Anagnou (Nicholas); H. Wajcman (Henri); R.C. Hardison (Ross)


    textabstractHbVar ( is a relational database developed by a multi-center academic effort to provide up-to-date and high quality information on the genomic sequence changes leading to hemoglobin variants and all types of thalassemia and

  7. Improvements in the HbVar database of human hemoglobin variants and thalassemia mutations for population and sequence variation studies.

    NARCIS (Netherlands)

    G.P. Patrinos (George); B. Giardine (Belinda); C. Riemer (Cathy); W. Miller (Webb); D.H. Chui (David); N.P. Anagnou (Nicholas); H. Wajcman (Henri); R.C. Hardison (Ross)


    textabstractHbVar ( is a relational database developed by a multi-center academic effort to provide up-to-date and high quality information on the genomic sequence changes leading to hemoglobin variants and all types of thalassemia and hemogl

  8. Expression of hemoglobin-α and β subunits in human vaginal epithelial cells and their functional significance (United States)

    Saha, Debarchana; Koli, Swanand; Patgaonkar, Mandar; Reddy, Kudumula Venkata Rami


    Hemoglobin (Hb) is a major protein involved in transport of oxygen (O2). It consists of Hb-α and Hb-β subunits, which are normally expressed by cells of erythroid lineage. However, till recently, it was not known whether non-erythroid cells like vaginal cells synthesize Hb and whether it has any functional significance. Therefore, we designed the following objectives: (1) to establish in-vitro culture system of human primary vaginal epithelial cells (hPVECs), (2) to determine whether Hb-α and Hb-β proteins are truly synthesized by hPVECs, (3) to evaluate the effect of LPS (lipopolysaccharide) on the expression of Hb-α and Hb-β proteins (4) to decipher the significance of the Hb-α and Hb-β expression in hPVECs and (5) to determine the molecular mechanism regulating the expression of Hb-α in hPVECs. To accomplish these studies, we applied a battery of assays such as RT-PCR, qRT-PCR, Flow cytometry, western blot, and immunofluorescence, Electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP). The results revealed the expression of Hb-α and Hb-β at both mRNA and protein level in hPVECs. The expression was significantly upregulated following LPS treatment (10μg/ml for 6 hrs) and these results are comparable with the expression induced by LPS in human vaginal epithelial cell line (VK2/E6E7). These cells constitutively produced low levels of pro-inflammatory (IL-6) and anti-inflammatory (IL-10) cytokines. Also, the response of phosphorylated (p65)-NF-κB to LPS was upregulated with increased expression of IL-6, Toll-like receptor-4 (TLR4) and human beta defensin-1 (hBD-1) in hPVECs and VK2/E6E7 cells. However, Bay 11–7082 treatment (5μM for 24 hrs) could neutralize the effect of LPS-induced p65-NF-κB activity and represses the production`of Hb-α and Hb-β. The results of EMSA revealed the presence of putative binding sites of NF-κB in the human Hb-α promoter region (nt-115 to -106). ChIP analysis confirmed the binding of NF

  9. Structure-function studies of histone H3/H4 tetramer maintenance during transcription by chaperone Spt2. (United States)

    Chen, Shoudeng; Rufiange, Anne; Huang, Hongda; Rajashankar, Kanagalaghatta R; Nourani, Amine; Patel, Dinshaw J


    Cells use specific mechanisms such as histone chaperones to abrogate the inherent barrier that the nucleosome poses to transcribing polymerases. The current model postulates that nucleosomes can be transiently disrupted to accommodate passage of RNA polymerases and that histones H3 and H4 possess their own chaperones dedicated to the recovery of nucleosomes. Here, we determined the crystal structure of the conserved C terminus of human Suppressors of Ty insertions 2 (hSpt2C) chaperone bound to an H3/H4 tetramer. The structural studies demonstrate that hSpt2C is bound to the periphery of the H3/H4 tetramer, mimicking the trajectory of nucleosomal-bound DNA. These structural studies have been complemented with in vitro binding and in vivo functional studies on mutants that disrupt key intermolecular contacts involving two acidic patches and hydrophobic residues on Spt2C. We show that contacts between both human and yeast Spt2C with the H3/H4 tetramer are required for the suppression of H3/H4 exchange as measured by H3K56ac and new H3 deposition. These interactions are also crucial for the inhibition of spurious transcription from within coding regions. Together, our data indicate that Spt2 interacts with the periphery of the H3/H4 tetramer and promotes its recycling in the wake of RNA polymerase. © 2015 Chen et al.; Published by Cold Spring Harbor Laboratory Press.

  10. Hemoglobin variants: biochemical properties and clinical correlates. (United States)

    Thom, Christopher S; Dickson, Claire F; Gell, David A; Weiss, Mitchell J


    Diseases affecting hemoglobin synthesis and function are extremely common worldwide. More than 1000 naturally occurring human hemoglobin variants with single amino acid substitutions throughout the molecule have been discovered, mainly through their clinical and/or laboratory manifestations. These variants alter hemoglobin structure and biochemical properties with physiological effects ranging from insignificant to severe. Studies of these mutations in patients and in the laboratory have produced a wealth of information on hemoglobin biochemistry and biology with significant implications for hematology practice. More generally, landmark studies of hemoglobin performed over the past 60 years have established important paradigms for the disciplines of structural biology, genetics, biochemistry, and medicine. Here we review the major classes of hemoglobin variants, emphasizing general concepts and illustrative examples.

  11. N-terminal glycation of proteins and peptides in foods and in vivo: evaluation of N-(2-furoylmethyl)valine in acid hydrolyzates of human hemoglobin. (United States)

    Penndorf, Ilka; Li, Changhao; Schwarzenbolz, Uwe; Henle, Thomas


    Specific determination of N-(2-furoylmethyl)valine (FM-Val) together with furosine in acid hydrolyzates of human hemoglobin of healthy volunteers (n = 6) and diabetic patients (n = 14) by means of reversed-phase HPLC with electrospray ionization-time-of-flight mass spectroscopy is reported. Whereas FM-Val is formed during acid hydrolysis of the N-terminal hemoglobin adduct N-fructosylvaline, furosine results from acid degradation of lysine residues glycated at the epsilon-amino group. Quantification was based on the use of synthesized isotopomers, namely N-[2-(13C6)furoylmethyl]valine and N-epsilon-[2-(13C6)furoylmethyl]lysine, thus enabling interference-free detection and calibration. Taking the conversion factors into account, the amount of N-terminally bound N-fructosylvaline in human hemoglobin was between 518 and 774 pmol/mg protein for healthy volunteers and between 586 and 1426 pmol/mg protein for diabetic patients. Derivatization at the side chain of peptide-bound lysine residues to N-epsilon-fructosyllysine was from 1156 to 1753 pmol/mg protein for healthy controls and from 1191 to 2409 pmol/mg protein for diabetics. For these patients, the amount of N-fructosylvaline showed good correlation with the values for HbA(1c). The significantly higher relative extent of glycation at the N terminus compared to side-chain glycation points to a specific and intraindividual capacity for enzymatic deglycation in human erythrocytes, which can be assessed using the proposed method.

  12. Three Stilbene Tetramers from the Roots of Caragana sinica

    Institute of Scientific and Technical Information of China (English)

    MA, Da-You(马大友); LUO, Hong-Feng(骆宏丰); HU, Chang-Qi(胡昌奇)


    Three stilbene tetramers, carasinols A-C (1-3), along with three known substances, leachianol C, cararosinol A and stenophyllol B, were isolated from the roots of Caragana sinica. Their structures were elucidated by spectroscopy. It was found that compounds isolated except for stenophyllol B stimulated the proliferation of cultured osteoblasts.

  13. Dimer-tetramer transition controls RUNX1/ETO leukemogenic activity. (United States)

    Wichmann, Christian; Becker, Yvonne; Chen-Wichmann, Linping; Vogel, Vitali; Vojtkova, Anna; Herglotz, Julia; Moore, Sandra; Koch, Joachim; Lausen, Jörn; Mäntele, Werner; Gohlke, Holger; Grez, Manuel


    RUNX1/ETO, the fusion protein resulting from the chromosomal translocation t(8;21), is one of the most frequent translocation products in acute myeloid leukemia. Several in vitro and in vivo studies have shown that the homo-tetramerization domain of ETO, the nervy homology region 2 (NHR2), is essential for RUNX1/ETO oncogenic activity. We analyzed the energetic contribution of individual amino acids within the NHR2 to RUNX1/ETO dimer-tetramer transition and found a clustered area of 5 distinct amino acids with strong contribution to the stability of tetramers. Substitution of these amino acids abolishes tetramer formation without affecting dimer formation. Similar to RUNX1/ETO monomers, dimers failed to bind efficiently to DNA and to alter expression of RUNX1-dependent genes. RUNX1/ETO dimers do not block myeloid differentiation, are unable to enhance the self-renewal capacity of hematopoietic progenitors, and fail to induce leukemia in a murine transplantation model. Our data reveal the existence of an essential structural motif (hot spot) at the NHR2 dimer-tetramer interface, suitable for a molecular intervention in t(8;21) leukemias.

  14. Resveratrol tetramer of hopeaphenol isolated from Shorea johorensis (Dipterocarpaceae) (United States)

    Aisha, Farra; Din, Laily B.; Yaacob, W. A.


    Hopeaphenol (1) as a resveratrol tetramer was isolated from the bark of Shorea johorensis collected from Imbak Canyon, Sabah, Malaysia. The structure of this compound was determined by the spectroscopic evidences using 1H- and 13C-NMR assigned with HSQC, HMBC, 1H-1H COSY and 1H-1H NOESY spectra, mass spectrum, and by comparison with reported data.

  15. Spectroscopic interaction study of human serum albumin and human hemoglobin with Mersilea quadrifolia leaves extract mediated silver nanoparticles having antibacterial and anticancer activity (United States)

    Maji, Anukul; Beg, Maidul; Mandal, Amit Kumar; Das, Somnath; Jha, Pradeep K.; Kumar, Anoop; Sarwar, Shamila; Hossain, Maidul; Chakrabarti, Pinak


    This study looks into a safe, proficient and low-cost way for the preparation of novel silver nanoparticles by using 5% aqueous leaves extract of a medicinal plant, Marsilea quadrifolia (family: Marsileaceae) without using any external reducing and stabilizing agents. The synthesized AgNPs showed maximum UV-Vis absorbance at 435 nm due to surface plasmon resonance (SPR). The average diameter (∼22.5 nm) of AgNPs was measured from TEM analysis and was also supported by FE-SEM. The existence of a silver signal in EDX spectra supported the AgNPs formation and negative zeta potential value (-18.7 mV) which suggested its stability. FT-IR spectroscopic analysis showed that the functional groups like sbnd Osbnd H, sbnd Nsbnd H and sbnd Cdbnd O were responsible for the synthesis of AgNPs. The antibacterial activity of the AgNPs was tested against E. coli ATCC 25922. The anticancer potential of AgNPs was also assessed using two different cell lines, such as MCF-7 and HeLa. The interaction study of AgNPs with human serum albumin (HSA) and human hemoglobin (Hb) was performed by means of UV-Vis, fluorescence spectroscopy, Circular dichroism (CD) and zeta potential measurement. More negative zeta potential values of AgNPs-HSA/Hb (-21.1/-19.5 mV) complexes than AgNPs (-18.7 mV) indicated corresponding stability of bio-conjugates. The basic structure of HSA/Hb remained unchanged and its secondary structure was slightly changed upon interaction with the AgNPs concluded from Circular dichroism. So, it can be predicted that this AgNPs may be applied in the medical field.

  16. Characterization of the binding of metoprolol tartrate and guaifenesin drugs to human serum albumin and human hemoglobin proteins by fluorescence and circular dichroism spectroscopy. (United States)

    Duman, Osman; Tunç, Sibel; Kancı Bozoğlan, Bahar


    The interactions of metoprolol tartrate (MPT) and guaifenesin (GF) drugs with human serum albumin (HSA) and human hemoglobin (HMG) proteins at pH 7.4 were studied by fluorescence and circular dichroism (CD) spectroscopy. Drugs quenched the fluorescence spectra of HSA and HMG proteins through a static quenching mechanism. For each protein-drug system, the values of Stern-Volmer quenching constant, bimolecular quenching constant, binding constant and number of binding site on the protein molecules were determined at 288.15, 298.15, 310.15 and 318.15 K. It was found that the binding constants of HSA-MPT and HSA-GF systems were smaller than those of HMG-MPT and HMG-GF systems. For both drugs, the affinity of HMG was much higher than that of HSA. An increase in temperature caused a negative effect on the binding reactions. The number of binding site on blood proteins for MPT and GF drugs was approximately one. Thermodynamic parameters showed that MPT interacted with HSA through electrostatic attraction forces. However, hydrogen bonds and van der Waals forces were the main interaction forces in the formation of HSA-GF, HMG-MPT and HMG-GF complexes. The binding processes between protein and drug molecules were exothermic and spontaneous owing to negative ∆H and ∆G values, respectively. The values of binding distance between protein and drug molecules were calculated from Förster resonance energy transfer theory. It was found from CD analysis that the bindings of MPT and GF drugs to HSA and HMG proteins altered the secondary structure of HSA and HMG proteins.

  17. The role of the inherited disorders of hemoglobin, the first "molecular diseases," in the future of human genetics. (United States)

    Weatherall, David J


    Although the inherited hemoglobin disorders were the first genetic diseases to be explored at the molecular level, they still have important messages for the future of medical genetics. In particular, they can offer a better understanding of the evolutionary and population biology of genetic disease, the mechanisms that underlie the phenotypic diversity of monogenic disease, and how, by developing appropriate partnerships, richer countries can help low-income countries to evolve programs for the control and management of these diseases where, in many cases, they are particularly common.

  18. Direct determination of protonation states of histidine residues in a 2 A neutron structure of deoxy-human normal adult hemoglobin and implications for the Bohr effect. (United States)

    Kovalevsky, Andrey Y; Chatake, Toshiyuki; Shibayama, Naoya; Park, Sam-Yong; Ishikawa, Takuya; Mustyakimov, Marat; Fisher, Zoe; Langan, Paul; Morimoto, Yukio


    We have investigated the protonation states of histidine residues (potential Bohr groups) in the deoxy form (T state) of human hemoglobin by direct determination of hydrogen (deuterium) positions with the neutron protein crystallography technique. The reversible binding of protons is key to the allosteric regulation of human hemoglobin. The protonation states of 35 of the 38 His residues were directly determined from neutron scattering omit maps, with 3 of the remaining residues being disordered. Protonation states of 5 equivalent His residues--alpha His20, alpha His50, alpha His89, beta His143, and beta His146--differ between the symmetry-related globin subunits. The distal His residues, alpha His58 and beta His63, are protonated in the alpha 1 beta 1 heterodimer and are neutral in alpha 2 beta 2. Buried residue alpha His103 is found to be protonated in both subunits. These distal and buried residues have the potential to act as Bohr groups. The observed protonation states of His residues are compared to changes in their pK(a) values during the transition from the T to the R state and the results provide some new insights into our understanding of the molecular mechanism of the Bohr effect.

  19. Crystallographic analysis of human hemoglobin elucidates the structural basis of the potent and dual antisickling activity of pyridyl derivatives of vanillin

    Energy Technology Data Exchange (ETDEWEB)

    Abdulmalik, Osheiza [The Children’s Hospital of Philadelphia, Philadelphia, PA 19104 (United States); Ghatge, Mohini S.; Musayev, Faik N.; Parikh, Apurvasena [Virginia Commonwealth University, Richmond, VA 23298 (United States); Chen, Qiukan; Yang, Jisheng [The Children’s Hospital of Philadelphia, Philadelphia, PA 19104 (United States); Nnamani, Ijeoma [Duke University Medical Center, Durham, NC 27710 (United States); Danso-Danquah, Richmond [Virginia Commonwealth University, Richmond, VA 23298 (United States); Eseonu, Dorothy N. [Virginia Union University, Richmond, VA 23220 (United States); Asakura, Toshio [Duke University Medical Center, Durham, NC 27710 (United States); Abraham, Donald J.; Venitz, Jurgen; Safo, Martin K., E-mail: [Virginia Commonwealth University, Richmond, VA 23298 (United States); The Children’s Hospital of Philadelphia, Philadelphia, PA 19104 (United States)


    Pyridyl derivatives of vanillin increase the fraction of the more soluble oxygenated sickle hemoglobin and/or directly increase the solubility of deoxygenated sickle hemoglobin. Crystallographic analysis reveals the structural basis of the potent and dual antisickling activity of these derivatives. Vanillin has previously been studied clinically as an antisickling agent to treat sickle-cell disease. In vitro investigations with pyridyl derivatives of vanillin, including INN-312 and INN-298, showed as much as a 90-fold increase in antisickling activity compared with vanillin. The compounds preferentially bind to and modify sickle hemoglobin (Hb S) to increase the affinity of Hb for oxygen. INN-312 also led to a considerable increase in the solubility of deoxygenated Hb S under completely deoxygenated conditions. Crystallographic studies of normal human Hb with INN-312 and INN-298 showed that the compounds form Schiff-base adducts with the N-terminus of the α-subunits to constrain the liganded (or relaxed-state) Hb conformation relative to the unliganded (or tense-state) Hb conformation. Interestingly, while INN-298 binds and directs its meta-positioned pyridine-methoxy moiety (relative to the aldehyde moiety) further down the central water cavity of the protein, that of INN-312, which is ortho to the aldehyde, extends towards the surface of the protein. These studies suggest that these compounds may act to prevent sickling of SS cells by increasing the fraction of the soluble high-affinity Hb S and/or by stereospecific inhibition of deoxygenated Hb S polymerization.

  20. Resveratrol tetramer of hopeaphenol isolated from Shorea johorensis (Dipterocarpaceae)

    Energy Technology Data Exchange (ETDEWEB)

    Aisha, Farra; Din, Laily B.; Yaacob, W. A. [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor (Malaysia)


    Hopeaphenol (1) as a resveratrol tetramer was isolated from the bark of Shorea johorensis collected from Imbak Canyon, Sabah, Malaysia. The structure of this compound was determined by the spectroscopic evidences using {sup 1}H- and {sup 13}C-NMR assigned with HSQC, HMBC, {sup 1}H−{sup 1}H COSY and {sup 1}H−{sup 1}H NOESY spectra, mass spectrum, and by comparison with reported data.

  1. Impact of cryopreservation on tetramer, cytokine flow cytometry, and ELISPOT

    Directory of Open Access Journals (Sweden)

    Morse Michael A


    Full Text Available Abstract Background Cryopreservation of PBMC and/or overnight shipping of samples are required for many clinical trials, despite their potentially adverse effects upon immune monitoring assays such as MHC-peptide tetramer staining, cytokine flow cytometry (CFC, and ELISPOT. In this study, we compared the performance of these assays on leukapheresed PBMC shipped overnight in medium versus cryopreserved PBMC from matched donors. Results Using CMV pp65 peptide pool stimulation or pp65 HLA-A2 tetramer staining, there was significant correlation between shipped and cryopreserved samples for each assay (p ≤ 0.001. The differences in response magnitude between cryopreserved and shipped PBMC specimens were not significant for most antigens and assays. There was significant correlation between CFC and ELISPOT assay using pp65 peptide pool stimulation, in both shipped and cryopreserved samples (p ≤ 0.001. Strong correlation was observed between CFC (using HLA-A2-restricted pp65 peptide stimulation and tetramer staining (p Conclusion We conclude that all three assays show concordant results on shipped versus cryopreserved specimens, when using a peptide-based readout. The assays are also concordant with each other in pair wise comparisons using equivalent antigen systems.

  2. The Hemoglobin E Thalassemias (United States)

    Fucharoen, Suthat; Weatherall, David J.


    Hemoglobin E (HbE) is an extremely common structural hemoglobin variant that occurs at high frequencies throughout many Asian countries. It is a β-hemoglobin variant, which is produced at a slightly reduced rate and hence has the phenotype of a mild form of β thalassemia. Its interactions with different forms of α thalassemia result in a wide variety of clinical disorders, whereas its coinheritance with β thalassemia, a condition called hemoglobin E β thalassemia, is by far the most common severe form of β thalassemia in Asia and, globally, comprises approximately 50% of the clinically severe β-thalassemia disorders. PMID:22908199

  3. Procedure for preparing peptide-major histocompatibility complex tetramers for direct quantification of antigen-specific cytotoxic T lymphocytes

    Institute of Scientific and Technical Information of China (English)

    Xian-Hui He; Li-Hui Xu; Yi Liu


    AIM: To establish a simplified method for generating peptide-major histocompatibility complex (MHC) class I tetramers.METHODS: cDNAs encoding the extracellular domain of human lymphocyte antigen (HLA)-A*0201 heavy chain (A2) and β2-microglobulin (β2m) from total RNA extracted from leukocytes of HLA-A2+ donors were doned into separate expression vectors by reverse transcription-polymerase chain reaction. The recombinant A2 and β2m proteins were expressed in Escherichia coli strain BL21(DE3) and recovered from the inclusion body fraction. Soluble A2 proteins loaded with specific antigen peptides were refolded by dilution from the heavy chain in the presence of light chain β2m and HLA-A2-restricted peptide antigens. The refolded A2monomers were biotinylated with a commercial biotinylation enzyme (BirA) and purified by low pressure anion exchange chromatography on a Q-Sepharose (fast flow) column.The tetramers were then formed by mixing A2 monomers with streptavidin-PE in a molar ratio of 4:1. Flow cytometry was used to confirm the expected tetramer staining of CD8+ T cells.RESULTS: Recombinant genes for HLA-A*0201 heavy chain (A2) fused to a BirA substrate peptide (A2-BSP) and mature β2m from HLA-A2+ donor leukocytes were successfully doned and highly expressed in E. coli. Two soluble monomeric A2-peptide complexes were reconstituted from A2-BSP in the presence of β2m and peptides loaded with either human cytomegalovirus pp65495-503 peptide (NLVPMVATV,NLV; designated as A2-NLV) or influenza virus matrix protein Mp58-66 peptide (GILGFVFTL, GIL; designated as A2-GIL). Refolded A2-NLV or A2-GIL monomers were biotinylated and highly purified by single step anion exchange column chromatography. The tetramers were then formed by mixing the biotinylated A2-NLV or A2-GIL monomers with streptavidin-PE, leading to more than 80% multiplication as revealed by SDS-PAGE under non-reducing, unboiled conditions. Flow cytometry revealed that these tetramers could specifically

  4. Hemoglobin E disease and glycosylated hemoglobin


    Niharika Yedla; Mohammad Shafi Kuchay; Ambrish Mithal


    Glycosylated hemoglobin (HbA1C) is a routinely measured parameter to monitor long-term glycemic control in people with diabetes mellitus. The presence of hemoglobin (Hb) variants can affect the accuracy of HbA1C methods. Hb E variant is the most common Hb variant in South-east Asia and North-east India. In the presence of Hb E, HbA1C may not be detectable by ion-exchange chromatography (high-pressure liquid chromatography), but may be estimated by immunoassay technique and boronate affinity c...

  5. 99Tcm标记RGD环肽四聚体在神经胶质瘤裸鼠模型中的显像研究%Imaging of 99Tcm-cycllc RGD tetramer in nude mice bearing U87MG human glioma xenografts

    Institute of Scientific and Technical Information of China (English)

    余子璘; 贾兵; 刘昭飞; 史继云; 赵慧云; 杨志; 王凡


    Objective Multimeric cyclic RGD (Arg-Gly-Asp) peptides are capable of improving the integrin αvβ3-binding affinity due to the polyvalence effect.In this study,the authors prepare 99Tcm-la-bearing cyclic RGD tetramer E{E[c(RGDfK)]2}2,and evaluate its biodistribution and imaging in nude mice beating U87 MG human glioma xenografts with integrinαvβ3-positive.Methods 99Tcm-hydrazino-nictinamide (HYNIC)-E{E[c(RGDfK)]2}2 was prepared by two-step method,while HYNIC wag chosen as bifunctional chelator,and tricine and trisodium triphenylphosphine-3,3,3-trisuifonate (TPPTS) as coligands.The af-finity of c (RGDyK) monomer,HYNIC-E[c(RGDfK)]2 dimer and HYNIC-E{E[c(RGDfK)]2}2 tetramer to integrin αvβ3 was compared by in vitro competitive assay against binding of 125I-c(RGDyK)to integrin αvβ3.positive U87 MG human glioma cells.The biodistribution [the percentage of injection dose per gram of tissue(%ID/g)] and imaging were performed in nude mice bearing UB7MG human glioma xenografts.Re-suits The labeling yield of 99Tcm-HYNIC-E{E[c(RGDfK)2}2 was over 95%,and the radiochemical purity was more than 99%after purification with Sop-Pak C18 cartridge.The 50%inhibiting concentration (IC30) val-ues of c(RGDyk),HYNIC-E[c(RGDfK)]2 and HYNIC-E{E[c(RGDfK)]2}2 were 85.9,9.5 and 4.5 nmol/L, respectively.The result indicated that RGD tetramer possessed a significantly higher affinity to in-tegrinαvβ3.The biodistribution data showed that 99Tcm-HYNIC-E{E[c(RGDfK)]2}2 was excreted mainly through kidneys.The tumor uptake of 99Tcm-HYNIC-E{E[c(RGDfK)]2}2 was two times higher than 99Tcm- HYNIC-E[c(RGDfK)]2,at 1h postinjection,with the uptake of(10.32±0.07)%ID/g and(5.15±0.52)%ID/g,respectively,which was consistent with the in vitro competitive binding data.The tumor up-tale of 99Tcm-HYNIC.E{E[c(RGDfK)]2}2 was still as higher as(9.35±1.35)%ID/g at 4 h postinjec-tion, which demonstrated that the retention time of radiotracer in tumor was long enough.The imaging showed that tumor was clearly

  6. Spectrin tetramer formation is not required for viable development in Drosophila. (United States)

    Khanna, Mansi R; Mattie, Floyd J; Browder, Kristen C; Radyk, Megan D; Crilly, Stephanie E; Bakerink, Katelyn J; Harper, Sandra L; Speicher, David W; Thomas, Graham H


    The dominant paradigm for spectrin function is that (αβ)2-spectrin tetramers or higher order oligomers form membrane-associated two-dimensional networks in association with F-actin to reinforce the plasma membrane. Tetramerization is an essential event in such structures. We characterize the tetramerization interaction between α-spectrin and β-spectrins in Drosophila. Wild-type α-spectrin binds to both β- and βH-chains with high affinity, resembling other non-erythroid spectrins. However, α-spec(R22S), a tetramerization site mutant homologous to the pathological α-spec(R28S) allele in humans, eliminates detectable binding to β-spectrin and reduces binding to βH-spectrin ∼1000-fold. Even though spectrins are essential proteins, α-spectrin(R22S) rescues α-spectrin mutants to adulthood with only minor phenotypes indicating that tetramerization, and thus conventional network formation, is not the essential function of non-erythroid spectrin. Our data provide the first rigorous test for the general requirement for tetramer-based non-erythroid spectrin networks throughout an organism and find that they have very limited roles, in direct contrast to the current paradigm.

  7. Comparative study of the effect of BPA and its selected analogues on hemoglobin oxidation, morphological alterations and hemolytic changes in human erythrocytes. (United States)

    Maćczak, Aneta; Bukowska, Bożena; Michałowicz, Jaromir


    Bisphenol A (BPA) has been shown to provoke many deleterious impacts on human health, and thus it is now successively substituted by BPA analogues, whose effects have been poorly investigated. Up to now, only one study has been realized to assess the effect of BPA on human erythrocytes, which showed its significant hemolytic and oxidative potential. Moreover, no study has been conducted to evaluate the effect of BPA analogues on red blood cells. The purpose of the present study was to compare the impact of BPA and its selected analogues such as bisphenol F (BPF), bisphenol S (BPS) and bisphenol AF (BPAF) on hemolytic and morphological changes and hemoglobin oxidation (methemoglobin formation) of human erythrocytes. The erythrocytes were incubated with different bisphenols concentrations ranging from 0.5 to 500μg/ml for 1, 4 and 24h. The compounds examined caused hemolysis in human erythrocytes with BPAF exhibiting the strongest effect. All bisphenols examined caused methemoglobin formation with BPA inducing the strongest oxidative potential. Flow cytometry analysis showed that all bisphenols (excluding BPS) induced significant changes in erythrocytes size. Changes in red blood cells shape were conducted using phase contrast microscopy. It was noticed that BPA and BPAF induced echinocytosis, BPF caused stomatocytosis, while BPS did not provoke significant changes in shape of red blood cells. Generally, the results showed that BPS, which is the main substituent of bisphenol A in polymers and thermal paper production, exhibited significantly lower disturbance of erythrocyte functions than BPA.

  8. Universality in Efimov-associated tetramers in 4He (United States)

    Hiyama, E.; Kamimura, M.


    We calculated, using seven realistic 4He-4He potentials in the literature, the Efimov spectra of the 4He trimer and tetramer and analyzed the universality of the systems. The three-(four-)body Schrödinger equations were solved fully nonadiabatically with the high-precision calculation method employed in our previous work on the 4He trimer and tetramer [Phys. Rev. A 85, 022502 (2012), 10.1103/PhysRevA.85.022502; Phys. Rev. A 85, 062505 (2012), 10.1103/PhysRevA.85.062505]. We found the following universality in the four-boson system: (i) The critical scattering lengths at which the tetramer ground and excited states couple to the four-body threshold are independent of the choice of the two-body realistic potentials in spite of the difference in the short-range details and do not contradict the corresponding values observed in the experiments in ultracold alkali-metal atoms when scaled with the van der Waals length rvdW, and (ii) the four-body hyperradial potential has a repulsive barrier at the four-body hyperradius R4≈3 rvdW , which prevents the four particles from getting close together to explore nonuniversal features of the interactions at short distances. This result is an extension of the universality in Efimov trimers that the appearance of the repulsive barrier at the three-body hyperradius R3≈2 rvdW makes the critical scattering lengths independent of the short-range details of the interactions as reported in the literature and also in the present work for the 4He trimer with the realistic potentials.

  9. Preparation and termination of carbosilane dendrimer based on siloxane tetramer

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chung Kyun; Park, Eun Mi [Donga Univ., Pusan (Korea, Republic of)


    Dendritic macromolecules of the first to fourth generation were synthesized, using alkenylation and hydrosilation cycles with allylmagnesium bromide and dichloromethylsilane as building blocks and siloxane tetramer (Me(CH{sub 2}=CH)SiO){sub 4} as core molecule. By the reaction of the dichloromethylsilyl-capped generation (G4P) with p-bromophenol, p-phenylphenol and lithium phenyethynylide, dendrimers with specific functions (G4P-BP) (Mw: 16,300), G4P-PP (16,121), and G4P-PA (11,764) have been produced. Analysis of new dendrimers by NMR, UV and MALDI mass spectrometry suggests that they are pure and unified.

  10. Peroxisomal ATP-binding cassette transporters form mainly tetramers. (United States)

    Geillon, Flore; Gondcaille, Catherine; Raas, Quentin; Dias, Alexandre M M; Pecqueur, Delphine; Truntzer, Caroline; Lucchi, Géraldine; Ducoroy, Patrick; Falson, Pierre; Savary, Stéphane; Trompier, Doriane


    ABCD1 and its homolog ABCD2 are peroxisomal ATP-binding cassette (ABC) half-transporters of fatty acyl-CoAs with both distinct and overlapping substrate specificities. Although it is established that ABC half-transporters have at least to dimerize to generate a functional unit, functional equivalents of tetramers (i.e. dimers of full-length transporters) have also been reported. However, oligomerization of peroxisomal ABCD transporters is incompletely understood but is of potential significance because more complex oligomerization might lead to differences in substrate specificity. In this work, we have characterized the quaternary structure of the ABCD1 and ABCD2 proteins in the peroxisomal membrane. Using various biochemical approaches, we clearly demonstrate that both transporters exist as both homo- and heterotetramers, with a predominance of homotetramers. In addition to tetramers, some larger molecular ABCD assemblies were also found but represented only a minor fraction. By using quantitative co-immunoprecipitation assays coupled with tandem mass spectrometry, we identified potential binding partners of ABCD2 involved in polyunsaturated fatty-acid metabolism. Interestingly, we identified calcium ATPases as ABCD2-binding partners, suggesting a role of ABCD2 in calcium signaling. In conclusion, we have shown here that ABCD1 and its homolog ABCD2 exist mainly as homotetramers in the peroxisomal membrane. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  11. Hemoglobin E disease and glycosylated hemoglobin

    Directory of Open Access Journals (Sweden)

    Niharika Yedla


    Full Text Available Glycosylated hemoglobin (HbA1C is a routinely measured parameter to monitor long-term glycemic control in people with diabetes mellitus. The presence of hemoglobin (Hb variants can affect the accuracy of HbA1C methods. Hb E variant is the most common Hb variant in South-east Asia and North-east India. In the presence of Hb E, HbA1C may not be detectable by ion-exchange chromatography (high-pressure liquid chromatography, but may be estimated by immunoassay technique and boronate affinity chromatography. However, the result may be underestimated when correlated with plasma glucose and serum fructosamine levels. Clinicians should be aware of this limitation of HbA1C estimation in patients with Hb E and other Hb variants.

  12. MHC class II/ESO tetramer-based generation of in vitro primed anti-tumor T-helper lines for adoptive cell therapy of cancer. (United States)

    Poli, Caroline; Raffin, Caroline; Dojcinovic, Danijel; Luescher, Immanuel; Ayyoub, Maha; Valmori, Danila


    Generation of tumor-antigen specific CD4(+) T-helper (T(H)) lines through in vitro priming is of interest for adoptive cell therapy of cancer, but the development of this approach has been limited by the lack of appropriate tools to identify and isolate low frequency tumor antigen-specific CD4(+) T cells. Here, we have used recently developed MHC class II/peptide tetramers incorporating an immunodominant peptide from NY-ESO-1 (ESO), a tumor antigen frequently expressed in different human solid and hematologic cancers, to implement an in vitro priming platform allowing the generation of ESO-specific T(H) lines. We isolated phenotypically defined CD4(+) T-cell subpopulations from circulating lymphocytes of DR52b(+) healthy donors by flow cytometry cell sorting and stimulated them in vitro with peptide ESO(119-143), autologous APC and IL-2. We assessed the frequency of ESO-specific cells in the cultures by staining with DR52b/ESO(119-143) tetramers (ESO-tetramers) and TCR repertoire of ESO-tetramer(+) cells by co-staining with TCR variable β chain (BV) specific antibodies. We isolated ESO-tetramer(+) cells by flow cytometry cell sorting and expanded them with PHA, APC and IL-2 to generate ESO-specific T(H) lines. We characterized the lines for antigen recognition, by stimulation with ESO peptide or recombinant protein, cytokine production, by intracellular staining using specific antibodies, and alloreactivity, by stimulation with allo-APC. Using this approach, we could consistently generate ESO-tetramer(+) T(H) lines from conventional CD4(+)CD25(-) naïve and central memory populations, but not from effector memory populations or CD4(+)CD25(+) Treg. In vitro primed T(H) lines recognized ESO with affinities comparable to ESO-tetramer(+) cells from patients immunized with an ESO vaccine and used a similar TCR repertoire. In this study, using MHC class II/ESO tetramers, we have implemented an in vitro priming platform allowing the generation of ESO

  13. Spiroscytalin, a new tetramic acid and other metabolites of mixed biogenesis from Scytalidium cuboideum. (United States)

    Sy-Cordero, Arlene A; Figueroa, Mario; Raja, Huzefa A; Meza Aviña, Maria Elena; Croatt, Mitchell P; Adcock, Audrey F; Kroll, David J; Wani, Mansukh C; Pearce, Cedric J; Oberlies, Nicholas H


    Spiroscytalin (1), a new tetramic acid that possesses an uncommon spiro-ring fusion between a polyketide-derived octalin ring system and a 2,4-pyrrolidinedione, along with two known compounds, leporin B (2) and purpactin A (3), were isolated from a solid phase culture of the fungus Scytalidium cuboideum (MSX 68345). The molecular connectivity of 1-3 was determined using NMR spectroscopy and mass spectrometry. The relative configurations of 1 and 2 were determined by NOESY experiments. The absolute configuration of 1 was determined by electronic circular dichroism (ECD) via a combination of experimental measurements and computational calculations. While leporin B was known, it displayed activities that had not been reported previously, including cytotoxicity against three human tumor cell lines and antibacterial activity against Candida albicans and Staphylococcus aureus.

  14. Role of alpha-hemoglobin-stabilizing protein in normal erythropoiesis and beta-thalassemia. (United States)

    Weiss, Mitchell J; Zhou, Suiping; Feng, Liang; Gell, David A; Mackay, Joel P; Shi, Yigong; Gow, Andrew J


    Hemoglobin (Hb) synthesis is coordinated by homeostatic mechanisms to limit the accumulation of free alpha or beta subunits, which are cytotoxic. Alpha hemoglobin-stabilizing protein (AHSP) is an abundant erythroid protein that specifically binds free alphaHb, stabilizes its structure, and limits its ability to participate in chemical reactions that generate reactive oxygen species. Gene ablation studies in mice demonstrate that AHSP is required for normal erythropoiesis. AHSP-null erythrocytes are short-lived, contain Hb precipitates, and exhibit signs of oxidative damage. Loss of AHSP exacerbates beta-thalassemia in mice, indicating that altered AHSP expression or function could modify thalassemia phenotypes in humans, a topic that is beginning to be explored in clinical studies. We used biochemical, spectroscopic, and crystallographic methods to examine how AHSP stabilizes alphaHb. AHSP binds the G and H helices of alphaHb on a surface that largely overlaps with the alpha1-beta1 interface of HbA. This result explains previous findings that betaHb can competitively displace AHSP from alphaHb to form HbA tetramer. Remarkably, binding of AHSP to oxygenated alphaHb induces dramatic conformational changes and converts the heme-bound iron to an oxidized hemichrome state in which all six coordinate positions are occupied. This structure limits the reactivity of heme iron, providing a mechanism by which AHSP stabilizes alphaHb. These findings suggest a biochemical pathway through which AHSP might participate in normal Hb synthesis and modulate the severity of thalassemias. Moreover, understanding how AHSP stabilizes alphaHb provides a theoretical basis for new strategies to inhibit the damaging effects of free alphaHb that accumulates in beta-thalassemia.

  15. Interaction of thyroid hormone and hemoglobin: nature of the interaction and effect of hemoglobin on thyroid hormone radioimmunoassay

    Energy Technology Data Exchange (ETDEWEB)

    Davis, P.J.; Yoshida, K.; Schoenl, M.


    Gel filtration of human erythrocyte (RBC) lysate incubated with labeled thyroxine (Tu) or triiodothyronine (Tt) revealed co-elution of a major iodothyronine-binding fraction (R-2) and hemoglobin. Solutions of purified human hemoglobin and Tt also showed co-elution of hormone and hemoglobin. Because hematin and protoporphyrin were shown to bind labeled Tt, the oxygen-binding site on hemoglobin was excluded as the site of iodothyronine-hemoglobin interaction. Analysis of hormone binding by heme and globin moieties showed Tt binding to be limited to the heme fraction. Addition of excess unlabeled Tt to hemoglobin or heme incubated with labeled Tt indicated 75% to 90% of hormone binding was poorly dissociable. These observations suggested that the presence of hemoglobin in RBC lysate or in serum could influence the measurement of Tu and Tt by specific radioimmunoassay (RIA). Subsequent studies of the addition to serum of human hemoglobin revealed a significant reduction in Tt and Tu detectable by RIA in the presence of this protein. The effect was influenced by the concentration of hemoglobin and by duration and temperature of incubations of hemoglobin and serum prior to RIA.

  16. Comparison of Hemoglobin Transmition Spectrums of Healthy Persons and Patients with Schizophrenia Disorders


    Vlokh R.; Marsel L.; Vlokh I.; Moroz O.; Dudok K.


    The present paper is devoted to the study of human hemoglobin transmission spectrums that were divided into four groups: hemoglobin of healthy persons, patients with schizophrenia, persons and people with and without the prodrome of schizophrenia that are in genetic susceptibility with patients. The change of absorption spectrums of hemoglobin of these groups was determined. The shifting of transmission minimums of the hemoglobin that correspond to electronic transitions in the hemoglobin mol...


    Bunn, H. Franklin; Esham, William T.; Bull, Robert W.


    The glomerular filtration of hemoglobin (α2β2) was studied under conditions in which its dissociation into αβ dimers was experimentally altered. Rats receiving hemoglobin treated with the sulfhydryl reagent bis(N-maleimidomethyl) ether (BME) showed a much lower renal excretion and prolonged plasma survival as compared with animals injected with untreated hemoglobin. Plasma disappearance was also prolonged in dogs receiving BME hemoglobin. Gel filtration data indicated that under physiological conditions, BME hemoglobin had impaired subunit dissociation. In addition, BME hemoglobin showed a very high oxygen affinity and a decreased rate of auto-oxidation. Glomerular filtration was enhanced under conditions which favor the dissociation of hemoglobin into dimers. Cat hemoglobin, which forms subunits much more extensively than canine hemoglobin, was excreted more readily by the rat kidney. The renal uptake of 59Fe hemoglobin injected intra-arterially into rabbits varied inversely with the concentration of the injected dose. PMID:5778789

  18. DNA Mismatch Repair Interacts with CAF-1- and ASF1A-H3-H4-dependent Histone (H3-H4)2 Tetramer Deposition. (United States)

    Rodriges Blanko, Elena; Kadyrova, Lyudmila Y; Kadyrov, Farid A


    DNA mismatch repair (MMR) is required for the maintenance of genome stability and protection of humans from several types of cancer. Human MMR occurs in the chromatin environment, but little is known about the interactions between MMR and the chromatin environment. Previous research has suggested that MMR coincides with replication-coupled assembly of the newly synthesized DNA into nucleosomes. The first step in replication-coupled nucleosome assembly is CAF-1-dependent histone (H3-H4)2 tetramer deposition, a process that involves ASF1A-H3-H4 complex. In this work we used reconstituted human systems to investigate interactions between MMR and CAF-1- and ASF1A-H3-H4-dependent histone (H3-H4)2 tetramer deposition. We have found that MutSα inhibits CAF-1- and ASF1A-H3-H4-dependent packaging of a DNA mismatch into a tetrasome. This finding supports the idea that MMR occurs before the DNA mismatch is packaged into the tetrasome. Our experiments have also revealed that CAF-1- and ASF1A-H3-H4-dependent deposition of the histone (H3-H4)2 tetramers does not interfere with MMR reactions. In addition, we have established that unnecessary degradation of the discontinuous strand that takes place in both DNA polymerase δ (Pol δ)- and DNA polymerase ϵ (Pol ϵ)-dependent MMR reactions is suppressed by CAF-1- and ASF1A-H3-H4-dependent deposition of the histone (H3-H4)2 tetramers. These data suggest that CAF-1- and ASF1A-H3-H4-dependent deposition of the histone (H3-H4)2 tetramers is compatible with MMR and protects the discontinuous daughter strand from unnecessary degradation by MMR machinery.

  19. Tiopronin gold nanoparticle precursor forms aurophilic ring tetramer. (United States)

    Simpson, Carrie A; Farrow, Christopher L; Tian, Peng; Billinge, Simon J L; Huffman, Brian J; Harkness, Kellen M; Cliffel, David E


    In the two step synthesis of thiolate-monolayer protected clusters (MPCs), the first step of the reaction is a mild reduction of gold(III) by thiols that generates gold(I) thiolate complexes as intermediates. Using tiopronin (Tio) as the thiol reductant, the characterization of the intermediate Au(4)Tio(4) complex was accomplished with various analytical and structural techniques. Nuclear magnetic resonance (NMR), elemental analysis, thermogravimetric analysis (TGA), and matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) were all consistent with a cyclic gold(I)-thiol tetramer structure, and final structural analysis was gathered through the use of powder diffraction and pair distribution functions (PDF). Crystallographic data has proved challenging for almost all previous gold(I)-thiolate complexes. Herein, a novel characterization technique when combined with standard analytical assessment to elucidate structure without crystallographic data proved invaluable to the study of these complexes. This in conjunction with other analytical techniques, in particular mass spectrometry, can elucidate a structure when crystallographic data is unavailable. In addition, luminescent properties provided evidence of aurophilicity within the molecule. The concept of aurophilicity has been introduced to describe a select group of gold-thiolate structures, which possess unique characteristics, mainly red photoluminescence and a distinct Au-Au intramolecular distance indicating a weak metal-metal bond as also evidenced by the structural model of the tetramer. Significant features of both the tetrameric and the aurophilic properties of the intermediate gold(I) tiopronin complex are retained after borohydride reduction to form the MPC, including gold(I) tiopronin partial rings as capping motifs, or "staples", and weak red photoluminescence that extends into the Near Infrared region.

  20. Amyloid Fibrils from Hemoglobin

    Directory of Open Access Journals (Sweden)

    Nadishka Jayawardena


    Full Text Available Amyloid fibrils are a class of insoluble protein nanofibers that are formed via the self-assembly of a wide range of peptides and proteins. They are increasingly exploited for a broad range of applications in bionanotechnology, such as biosensing and drug delivery, as nanowires, hydrogels, and thin films. Amyloid fibrils have been prepared from many proteins, but there has been no definitive characterization of amyloid fibrils from hemoglobin to date. Here, nanofiber formation was carried out under denaturing conditions using solutions of apo-hemoglobin extracted from bovine waste blood. A characteristic amyloid fibril morphology was confirmed by transmission electron microscopy (TEM and atomic force microscopy (AFM, with mean fibril dimensions of approximately 5 nm diameter and up to several microns in length. The thioflavin T assay confirmed the presence of β-sheet structures in apo-hemoglobin fibrils, and X-ray fiber diffraction showed the characteristic amyloid cross-β quaternary structure. Apo-hemoglobin nanofibers demonstrated high stability over a range of temperatures (−20 to 80 °C and pHs (2–10, and were stable in the presence of organic solvents and trypsin, confirming their potential as nanomaterials with versatile applications. This study conclusively demonstrates the formation of amyloid fibrils from hemoglobin for the first time, and also introduces a cost-effective method for amyloid fibril manufacture using meat industry by-products.

  1. Hemoglobinas humanas: hipótese malária ou efeito materno? Human hemoglobins: malaria hypothesis or maternal effect?

    Directory of Open Access Journals (Sweden)

    Felipe R. Torres


    Full Text Available As hemoglobinopatias têm provido uma das poucas demonstrações convincentes da seleção, influenciando a freqüência de único gene na população humana. A alta taxa de desordens, tais como a anemia falciforme e a beta-talassemia, ocorridas em áreas subtropicais ou tropicais dentro do cinturão da malária, levou Haldane a propor que a malária pode ser o agente seletivo responsável que balanceia a perda dos genes para a talassemia e a anemia falciforme, por morte prematura dos homozigotos a partir do aumento do valor adaptativo de heterozigotos no ambiente com malária. Mas uma nova proposta surgiu para explicar a manutenção deste polimorfismo, baseada na fertilidade diferencial ou efeito parental. Alguns autores observaram uma distorção favorecendo a transmissão de alelos mutantes em áreas não endêmicas de malária. Com base nestas observações, esses autores propuseram um efeito materno para explicar tais distorções. Este estudo tem como objetivo apresentar uma revisão destes mecanismos envolvidos na manutenção do polimorfismo de hemoglobinopatias, desde seu modelo clássico até hipóteses alternativas que surgiram recentemente na literatura.Hemoglobinopathies are providing one of the few convincing demonstrations of selection, influencing the frequency of a single gene in the human population. The high rate of disorders, such as the sickle cell anemia and beta-thalassemia that occur in the subtropical or tropical regions within the strip affected by malaria, led Haldane to propose that malaria may be the selective agent responsible for balancing the loss of thalassemia and sickle cell anemia genes due to the early death of homozygous patients. But a new proposal appeared to explain the maintenance of these polymorphisms, based on the differential fertility or parental effect. Some authors observed a distortion favoring the transmission of mutant alleles in non-endemic malaria areas. Based on these observations, the

  2. Safety Evaluation of Hemoglobin-Albumin Cluster "HemoAct" as a Red Blood Cell Substitute

    National Research Council Canada - National Science Library

    Haruki, Risa; Kimura, Takuya; Iwasaki, Hitomi; Yamada, Kana; Kamiyama, Ikuo; Kohno, Mitsutomo; Taguchi, Kazuaki; Nagao, Saori; Maruyama, Toru; Otagiri, Masaki; Komatsu, Teruyuki


    A hemoglobin (Hb) wrapped covalently by human serum albumins (HSAs), a core-shell structured hemoglobin-albumin cluster designated as "HemoAct", is an O2-carrier designed for use as a red blood cell (RBC) substitute...

  3. Rice (Oryza) hemoglobins (United States)

    Hemoglobins (Hbs) corresponding to non-symbiotic (nsHb) and truncated (tHb) Hbs have been identified in rice (Oryza). This review discusses the major findings from the current studies on rice Hbs. At the molecular level, a family of the nshb genes, consisting of hb1, hb2, hb3, hb4 and hb5, and a sin...

  4. Anti-parallel dimer and tetramer formation of propylene carbonate

    Directory of Open Access Journals (Sweden)

    Ayana Tagawa


    Full Text Available Raman scattering and infrared (IR absorption spectra of enantiopure (R-propylene carbonate ((RPC and racemic propylene carbonate (PC were recorded at room temperature, 25 °C, in benzene (Bz solution and in the pure liquid state to investigate the presence of dimers and other higher order intermolecular associations. (RPC and PC both demonstrated a strong C=O stretching vibrational band. The band exhibited changes in its shape and resonance wavenumber highly dependent on the concentrations of PCs, whereas a difference between the chirality of (RPC and PC had little influence. In an extremely dilute condition, doubly split bands were observed at 1807 and 1820 cm-1 in both Raman and IR spectra, which are assigned to the characteristic bands of isolated monomeric PCs. An additional band appeared at 1795 cm-1 in a dilute to concentrated regime, and its magnitude strengthened with increasing concentrations accompanied with slight increasing in the magnitude of 1807 cm-1 band in Raman spectra, while an increase in the magnitude of 1807 cm-1 band was clearly greater than that of 1795 cm-1 band in IR spectra. The spectrum changes at 1795 and 1807 cm-1 were attributed to characteristics of anti-parallel dimer formation of PCs caused by strong dipole-dipole interactions between C=O groups. Moreover, another additional signal was clearly observed at 1780-1790 cm-1 in a concentrated regime, and became the primary signal in the pure liquid state with slight increasing in the intensity of 1795 cm-1 band in Raman spectra. On the other hand, in IR spectra the observed increasing of 1780-1790 cm-1 band was much less than that of 1795 cm-1 band. These newly found spectrum changes in the concentrated regime are attributed to the formation of anti-parallel tetramers of PCs based on the characteristics of band selection rule found in Raman and IR spectra. Equilibrium constants for the anti-parallel dimer (KD and tetramer formation (KT of PCs in Bz solution and in

  5. Probing the biological evaluations of a new designed Pt(II) complex using spectroscopic and theoretical approaches: human hemoglobin as a target. (United States)

    Abazari, Omid; Shafaei, Zahra; Divsalar, Adeleh; Eslami-Moghadam, Mahbubeh; Ghalandari, Behafarid; Saboury, Ali Akbar


    In recent years, using heavy metal compounds such as platinum as anticancer agent is one of the common ways in chemical therapy. In this study, a new anticancer compound of glycine derivatives of Pt(II) complex (amyl-glycine1, 10-phenanthroline Platinum nitrate) was designed, and the biological effects of this novel compound on the alterations in the function and structure of human hemoglobin (Hb) at different temperatures of 25 and 37°C were assessed by applying various spectroscopic (fluorescence and circular dichroism (CD)) and theoretical methods. Fluorescence data indicated the strong ability of Pt(II) complex to quench the intrinsic fluorescence of Hb. The binding constant, number of binding sites, and thermodynamic parameters at two temperatures were calculated, and the results indicated the major possibility of occurring van der Waals force or hydrogen bond interactions in the Pt(II) complex-Hb interaction. For evaluating the alteration of secondary structure of Hb upon interaction with various concentrations of complex, far-UV CD spectra were used and it was observed that in high dose of complex, significant changes were occurred which is indicative of some side effects in overdosing of this complex. On the other hand, the molecular docking results illustrate that are well in agreement in obtaining data with spectroscopy. Above results suggested that using Pt(II) complex as an anticancer agent, model drug in high-dose usage might cause some disordering in structure and function of Hb as well as improve understanding of the side effects of newly designed metal anticancer drugs undergoing.

  6. Molecular evolution of hemoglobins of Antarctic fishes (Notothenioidei)

    NARCIS (Netherlands)

    Stam, W.T.; Beintema, J.J; D Avino, R.; Tamburrini, M.; di Prisco, G.


    Amino acid sequences of alpha- and beta-chains of human hemoglobin and of hemoglobins of coelacanth and 24 teleost fish species, including 11 antarctic and two temperate Notothenioidei, were analyzed using maximum parsimony. Trees were derived for the alpha- and beta-chains separately and for tandem

  7. CD1b-mycolic acid tetramers demonstrate T-cell fine specificity for mycobacterial lipid tails. (United States)

    Van Rhijn, Ildiko; Iwany, Sarah K; Fodran, Peter; Cheng, Tan-Yun; Gapin, Laurent; Minnaard, Adriaan J; Moody, D Branch


    Mycobacterium tuberculosis synthesizes a thick cell wall comprised of mycolic acids (MA), which are foreign antigens for human T cells. T-cell clones from multiple donors were used to determine the fine specificity of MA recognition by human αβ T cells. Most CD1-presented lipid antigens contain large hydrophilic head groups comprised of carbohydrates or peptides that dominate patterns of T-cell specificity. MA diverges from the consensus antigen motif in that it lacks a head group. Using multiple forms of natural and synthetic MA and MA-specific T-cells with different T-cell receptors, we found that, unlike antigens with larger head groups, lipid length strongly controlled T-cell responses to MA. In addition, the three forms of MA that naturally occur in M. tuberculosis that differ in modifications on the lipid tail, differ in their potency for activating MA-specific T-cell clones. Thus, naturally occurring MA forms should be considered as separate, partly cross-reactive antigens. Two of the three forms of MA could be loaded onto human CD1b proteins, creating working CD1b-MA tetramers. The creation of CD1b-MA tetramers represents a new tool for future studies that track the effector functions and kinetics of MA-specific T-cells ex vivo. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Selectivity in subunit composition of Ena/VASP tetramers. (United States)

    Riquelme, Daisy N; Meyer, Aaron S; Barzik, Melanie; Keating, Amy; Gertler, Frank B


    The members of the actin regulatory family of Ena/VASP proteins form stable tetramers. The vertebrate members of the Ena/VASP family, VASP, Mena and EVL, have many overlapping properties and expression patterns, but functional and regulatory differences between paralogues have been observed. The formation of mixed oligomers may serve a regulatory role to refine Ena/VASP activity. While it has been assumed that family members can form mixed oligomers, this possibility has not been investigated systematically. Using cells expressing controlled combinations of VASP, Mena and EVL, we evaluated the composition of Ena/VASP oligomers and found that VASP forms oligomers without apparent bias with itself, Mena or EVL. However, Mena and EVL showed only weak hetero-oligomerization, suggesting specificity in the association of Ena/VASP family members. Co-expression of VASP increased the ability of Mena and EVL to form mixed oligomers. Additionally, we found that the tetramerization domain (TD) at the C-termini of Ena/VASP proteins conferred the observed selectivity. Finally, we demonstrate that replacement of the TD with a synthetic tetramerizing coiled coil sequence supports homo-oligomerization and normal VASP subcellular localization.

  9. Fluorescence Spectra and Enzymatic Property of Hemoglobin as Mimetic Peroxidase

    Institute of Scientific and Technical Information of China (English)

    Li De-jia; Li Hai-cheng; Zou Guo-lin


    Intrinsic fluorescence emission maxima of hemoglobin(Hb) was investigated in relation to peroxidase property of Hb. The peroxidase activity of Hb was based on its catalytic activity for oxidation of o-phenylenediamine by hydrogen peroxide. Hb was treated in the condition (temperature,ethanol and salt) that tetramer-dimer equilibrium of Hb is shifted to the dimer state and its fluorescence spectrum was measured. When Hb treated in temperature (60-70 ℃ ), ethanol concentration (60 %-70 % ) and NaCl concentration (2.5-3.0 mol/L), the fluorescence emission maxima of Hb shifted towards red wavelength and its activity decreased quickly.Experimental results revealed that the activity and stability of Hb as mimetic peroxidase was closely relative to the hydrophobic environment of active center of Hb, and when Hb (FeⅡ) converted into met Hb (FeⅢ ), its activity was 1. 6times as much as that of Hb.

  10. Hemoglobin interacting proteins and implications of spectrin hemoglobin interaction. (United States)

    Basu, Avik; Chakrabarti, Abhijit


    In this report we have analyzed interacting partners of hemoglobin inside erythrocyte and sought possible implications of hemoglobin-spectrin interaction. Our list of identified cytosolic hemoglobin interacting proteins includes redox regulators like peroxiredoxin-2, Cu-Zn superoxide dismutase, catalase, aldehyde dehydrogenase-1, flavin reductase and chaperones like HSP70, α-hemoglobin stabilizing protein. Others include metabolic enzymes like carbonic anhydrase-1, selenium binding protein-1, purine nucleoside phosphorylase and nucleoside diphosphate kinase. Additionally, various membrane proteins like α and β spectrin, ankyrin, band3, protein4.1, actin and glyceraldehyde 3 phosphate dehydrogenase have been shown to interact with hemoglobin. Our result indicates that major membrane skeleton protein spectrin, that also has a chaperone like activity, helps to fold the unstable alpha-globin chains in vitro. Taken together our results could provide insight into a protein network evolved around hemoglobin molecule inside erythrocyte that may add a new perspective in understanding the hemoglobin function and homeostasis.

  11. Hemoglobin oxidative stress

    Energy Technology Data Exchange (ETDEWEB)

    Croci, S.; Ortalli, I.; Pedrazzi, G. [University of Parma, Istituto di Scienze Fisiche, INFM-Udr Parma (Italy); Passeri, G. [University of Parma, Dipartimento di Medicina Interna e Scienze Biomediche (Italy); Piccolo, P. [University of Parma, Istituto di Clinica chirurgica Generale, Toracica e Vascolare (Italy)


    Venous blood obtained from healthy donors and from patients suffering from breast cancer have been treated with acetylphenylhydrazine (APH) for different time. Moessbauer spectra of the packed red cells have been recorded and compared. The largest difference occurs after 50 min of treatment with APH where the patient samples show a broad spectral pattern indicating an advanced hemoglobin oxidation. These results may have some relevance in early cancer diagnosis.

  12. Bohr effect of hemoglobins: Accounting for differences in magnitude. (United States)

    Okonjo, Kehinde O


    The basis of the difference in the Bohr effect of various hemoglobins has remained enigmatic for decades. Fourteen amino acid residues, identical in pairs and located at specific 'Bohr group positions' in human hemoglobin, are implicated in the Bohr effect. All 14 are present in mouse, 11 in dog, eight in pigeon and 13 in guinea pig hemoglobin. The Bohr data for human and mouse hemoglobin are identical: the 14 Bohr groups appear at identical positions in both molecules. The dog data are different from the human because three Bohr group positions are occupied by non-ionizable groups in dog hemoglobin; the pigeon data are vastly different from the human because six Bohr group positions are occupied by non-ionizable groups in pigeon hemoglobin. The guinea pig data are quite complex. Quantitative analyses showed that only the pigeon data could be fitted with the Wyman equation for the Bohr effect. We demonstrate that, apart from guinea pig hemoglobin, the difference between the Bohr effect of each of the other hemoglobins and of pigeon hemoglobin can be accounted for quantitatively on the basis of the occupation of some of their Bohr group positions by non-ionizable groups in pigeon hemoglobin. We attribute the anomalous guinea pig result to a new salt-bridge formed in its R2 quaternary structure between the terminal NH3(+) group of one β-chain and the COO(-) terminal group of the partner β-chain in the same molecule. The pKas of this NH3(+) group are 6.33 in the R2 and 4.59 in the T state.

  13. New insight on biological interaction analysis: new nanocrystalline mixed metal oxide SPME fiber for GC-FID analysis of BTEX and its application in human hemoglobin-benzene interaction studies. (United States)

    Hosseinzadeh, Reza; Moosavi Movahedi, Ali Akbar; Ghourchian, Hedayatollah


    Nanocrystalline mixed metal oxides (MMO) of various metal cations were synthesized and were used for coating a piece of copper wire as a new high sensitive solid phase micro extraction (SPME) fiber in extraction and determination of BTEX compounds from the headspace of aqueous samples prior to GC-FID analysis. Under optimum extraction conditions, the proposed fiber exhibited low detection limits, and quantification limits, good reproducibility, simple and fast preparation method, high fiber capacity and high thermal and mechanical durability. These are some of the most important advantages of the new fiber. The proposed fiber was used for human hemoglobin upon interaction with benzene. Binding isotherm, Scatchard and Klotz logarithmic plots were constructed using HS-SPME-GC data, accurately. The obtained binding isotherm analyzed using Hill method. The Hill parameters have been obtained by calculating saturation parameter from the ratio of measured chromatographic peak areas in the presence and absence of hemoglobin. In this interaction, Hill coefficient and Hill constant determined as (nH = 6.14 and log KH = 6.47) respectively. These results reveal the cooperativity of hemoglobin upon interaction with benzene.

  14. Identificação e caracterização de variantes novas e raras da hemoglobina humana Identification of characterization of novel and rare variants of human hemoglobin

    Directory of Open Access Journals (Sweden)

    Elza M. Kimura


    Full Text Available As anormalidades estruturais da hemoglobina estão entre as doenças genéticas mais comumente encontradas nas populações humanas. O Laboratório de Hemoglobinopatias do Departamento de Patologia Clínica da Faculdade de Ciências Médicas da Universidade Estadual de Campinas - Unicamp, localizado em Campinas, no estado de São Paulo, região Sudeste do Brasil, realizou, em seus 27 anos de existência, cerca de 130.000 diagnósticos. Entre as variantes estruturais detectadas, as hemoglobinas S, C e D-Punjab foram, como esperado, as mais freqüentes, porém um número expressivo de outras hemoglobinas anômalas, novas e raras, também foi encontrado. Esses achados estão sumarizados no presente artigo.Hemoglobin structural abnormalities are among the most commonly found human genetic diseases. The Laboratory of Hemoglobinopathies in the Clinical Pathology Department of the Medical Sciences School of the State University in Campinas - Unicamp, São Paulo, Southeastern Brazil, carried out, in its 27 years of activity, about 130,000 diagnoses. As expected, hemoglobins S, C and D were the most frequently observed variants, but an expressive number of other abnormal, novel and rare hemoglobins, was also detected. These findings are summarized in the present article.

  15. New insight on biological interaction analysis: new nanocrystalline mixed metal oxide SPME fiber for GC-FID analysis of BTEX and its application in human hemoglobin-benzene interaction studies.

    Directory of Open Access Journals (Sweden)

    Reza Hosseinzadeh

    Full Text Available Nanocrystalline mixed metal oxides (MMO of various metal cations were synthesized and were used for coating a piece of copper wire as a new high sensitive solid phase micro extraction (SPME fiber in extraction and determination of BTEX compounds from the headspace of aqueous samples prior to GC-FID analysis. Under optimum extraction conditions, the proposed fiber exhibited low detection limits, and quantification limits, good reproducibility, simple and fast preparation method, high fiber capacity and high thermal and mechanical durability. These are some of the most important advantages of the new fiber. The proposed fiber was used for human hemoglobin upon interaction with benzene. Binding isotherm, Scatchard and Klotz logarithmic plots were constructed using HS-SPME-GC data, accurately. The obtained binding isotherm analyzed using Hill method. The Hill parameters have been obtained by calculating saturation parameter from the ratio of measured chromatographic peak areas in the presence and absence of hemoglobin. In this interaction, Hill coefficient and Hill constant determined as (nH = 6.14 and log KH = 6.47 respectively. These results reveal the cooperativity of hemoglobin upon interaction with benzene.

  16. 76 FR 51041 - Hemoglobin Standards and Maintaining Adequate Iron Stores in Blood Donors; Public Workshop (United States)


    ... HUMAN SERVICES Food and Drug Administration Hemoglobin Standards and Maintaining Adequate Iron Stores in... workshop. The Food and Drug Administration (FDA) is announcing a public workshop entitled: ``Hemoglobin... discuss blood donor hemoglobin and hematocrit qualification standards in the United States, its impact...

  17. Hemoglobin Drift after Cardiac Surgery (United States)

    George, Timothy J.; Beaty, Claude A.; Kilic, Arman; Haggerty, Kara A.; Frank, Steven M.; Savage, William J.; Whitman, Glenn J.


    Introduction Recent literature suggests that a restrictive approach to red blood cell transfusions is associated with improved outcomes in cardiac surgery (CS) patients. Even in the absence of bleeding, intravascular fluid shifts cause hemoglobin levels to drift postoperatively, possibly confounding the decision to transfuse. We undertook this study to define the natural progression of hemoglobin levels in postoperative CS patients. Methods We included all CS patients from 10/10-03/11 who did not receive a postoperative transfusion. Primary stratification was by intraoperative transfusion status. Change in hemoglobin was evaluated relative to the initial postoperative hemoglobin. Maximal drift was defined as the maximum minus the minimum hemoglobin for a given hospitalization. Final drift was defined as the difference between initial and discharge hemoglobin. Results Our final cohort included 199 patients, 71(36%) received an intraoperative transfusion while 128(64%) did not. The average initial and final hemoglobin for all patients were 11.0±1.4g/dL and 9.9±1.3g/dL, respectively, an final drift of 1.1±1.4g/dL. The maximal drift was 1.8±1.1g/dL and was similar regardless of intraoperative transfusion status(p=0.9). Although all patients’ hemoglobin initially dropped, 79% of patients reached a nadir and experienced a mean recovery of 0.7±0.7g/dL by discharge. On multivariable analysis, increasing CPB time was significantly associated with total hemoglobin drift(Coefficient/hour: 0.3[0.1–0.5]g/dL, p=0.02). Conclusions In this first report of hemoglobin drift following CS, although all postoperative patients experienced downward hemoglobin drift, 79% of patients exhibited hemoglobin recovery prior to discharge. Physicians should consider the eventual upward hemoglobin drift prior to administering red cell transfusions. PMID:22609121

  18. Why do cytotoxic T lymphocytes fail to eliminate hepatitis C virus? Lessons from studies using major histocompatibility complex class I peptide tetramers. (United States)

    Lechner, F; Sullivan, J; Spiegel, H; Nixon, D F; Ferrari, B; Davis, A; Borkowsky, B; Pollack, H; Barnes, E; Dusheiko, G; Klenerman, P


    Hepatitis C virus (HCV) infection is a major public health problem, affecting an estimated 3% of the world's population, and over 10% in some countries. Infection in most cases becomes persistent, and can lead to hepatic inflammation, fibrosis and liver failure. The T lymphocyte reponse, in particular that mediated by cytotoxic T lymphocytes (CTLs), is likely to be involved in determining the outcome of infection, although its overall role is not clear. The use of major histocompatibility complex (MHC) class I peptide tetrameric complexes (tetramers) to study antiviral CTL responses has revolutionized our approach to the study of human infection. We have used a panel of MHC class I tetramers to analyse immune responses in HCV-infected individuals at various stages of disease. We find that the CTL response against HCV is vigorous in its early phases but dwindles over time both in terms of lymphocyte number and function. A number of potential explanations for this 'CTL failure' are discussed.

  19. Interaction of toxic azo dyes with heme protein: biophysical insights into the binding aspect of the food additive amaranth with human hemoglobin. (United States)

    Basu, Anirban; Kumar, Gopinatha Suresh


    A biophysical study on the interaction of the food colorant amaranth with hemoglobin was undertaken. Spectrophotometric and spectrofluorimetric studies proposed for an intimate binding interaction between the dye and the protein. The dye quenched the fluorescence of the protein remarkably and the mechanism of quenching was found to be static in nature. Synchronous fluorescence studies suggested that the polarity around the tryptophan residues was altered in the presence of amaranth whereas the polarity around tyrosine residues remained largely unaltered. 3D fluorescence, FTIR and circular dichroism results suggested that the binding reaction caused conformational changes in hemoglobin. The negative far-UV CD bands exhibited a significantly large decrease in magnitude in the presence of amaranth. From calorimetry studies it was established that the binding was driven by a large positive entropic contribution and a small but favorable enthalpy change.

  20. Comparison of Hemoglobins from Various Subjects Living in Hypoxia

    Directory of Open Access Journals (Sweden)



    Full Text Available The aim of this research was to obtain the different characteristics of haemoglobin molecules in subjects under hypoxic condition, namely eel, catfish, suckermouth fish, green sea turtle using an electrophoresis technique. We used human umbilical cord blood and thalassemia patient blood, as well as a normal adult-human blood as controls. The proteins obtained after electrophoresis process were stained with two different colouring techniques, each based on different principles. Both staining techniques gave practically identical results. Subject that live in hypoxic condition has a different haemoglobin in comparison to the one found in adult human live in normal oxygen condition (normoxia. These hypoxia-adapted or -needed hemoglobin migrate slower than adult human hemoglobin from normoxia. This observation suggests that hemoglobin which is needed to live in hypoxic condition or environment is a different molecule. Whether this hemoglobin from hypoxic condition has a higher affinity to oxygen is not yet known.


    Directory of Open Access Journals (Sweden)

    Olair Carlos Beltrame


    Full Text Available Diabetes mellitus (DM commonly occurs in dogs, and the laboratorial confirmation is carried out by glycemia test. The diagnosis and monitoring in humans is made by glycated hemoglobin and fructosamine concentrations. The objective of this study was to diagnose DM in 19 dogs, by evaluating seric glucose, glycated hemoglobin and fructosamine concentrations. Six dogs with DM and treated with insulin were assisted during a twelve-month period, by means of the same blood analysis, until the death (three dogs or glycemic control (three dogs. Glucose, glycated hemoglobin and fructosamine increased in all dogs with DM, and dogs that did not survive presented higher glycated hemoglobin and seric glucose values than those that survived at the last evaluation. The results showed the importance of evaluating glycated hemoglobin and fructosamine in dogs with DM to diagnose and control treatment effectiveness.

  2. Oxygen binding to partially nitrosylated hemoglobin. (United States)

    Fago, Angela; Crumbliss, Alvin L; Hendrich, Michael P; Pearce, Linda L; Peterson, Jim; Henkens, Robert; Bonaventura, Celia


    Reactions of nitric oxide (NO) with hemoglobin (Hb) are important elements in protection against nitrosative damage. NO in the vasculature is depleted by the oxidative reaction with oxy Hb or by binding to deoxy Hb to generate partially nitrosylated Hb (Hb-NO). Many aspects of the formation and persistence of Hb-NO are yet to be clarified. In this study, we used a combination of EPR and visible absorption spectroscopy to investigate the interactions of partially nitrosylated Hb with O2. Partially nitrosylated Hb samples had predominantly hexacoordinate NO-heme geometry and resisted oxidation when exposed to O2 in the absence of anionic allosteric effectors. Faster oxidation occurred in the presence of 2,3-diphosphoglycerate (DPG) or inositol hexaphosphate (IHP), where the NO-heme derivatives had higher levels of pentacoordinate heme geometry. The anion-dependence of the NO-heme geometry also affected O2 binding equilibria. O2-binding curves of partially nitrosylated Hb in the absence of anions were left-shifted at low saturations, indicating destabilization of the low O2 affinity T-state of the Hb by increasing percentages of NO-heme, much as occurs with increasing levels of CO-heme. Samples containing IHP showed small decreases in O2 affinity, indicating shifts toward the low-affinity T-state and formation of inert α-NO/β-met tetramers. Most remarkably, O2-equilibria in the presence of the physiological effector DPG were essentially unchanged by up to 30% NO-heme in the samples. As will be discussed, under physiological conditions the interactions of Hb with NO provide protection against nitrosative damage without impairing O2 transport by Hb's unoccupied heme sites. This article is part of a Special Issue entitled: Oxygen Binding and Sensing Proteins. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Structure of hemoglobin M Boston, a variant with a five-coordinated ferric heme. (United States)

    Pulsinelli, P D; Perutz, M F; Nagel, R L


    X-ray analysis of the natural valency hybrid alpha(2) (+M Boston)beta(2) (deoxy) shows that the ferric iron atoms in the abnormal alpha subunits are bonded to the phenolate side chains of the tyrosines that have replaced the distal histidines; the iron atoms are displaced to the distal side of the porphyrin ring and are not bonded to the proximal histidines. The resulting changes in tertiary structure of the alpha subunits stabilize the hemoglobin tetramer in the quaternary deoxy structure, which lowers the oxygen affinity of the normal beta subunits and causes cyanosis. The strength of the bond from the ferric iron to the phenolate oxygen appears to be the main factor responsible for the many abnormal properties of hemoglobin M Boston.

  4. Real-time tracking of CO migration and binding in the α and β subunits of human hemoglobin via 150-ps time-resolved Laue crystallography

    Energy Technology Data Exchange (ETDEWEB)

    Schotte, Friedrich; Cho, Hyun Sun [Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520 (United States); Soman, Jayashree [Department of Biochemistry and Cell Biology, and W.M. Keck Center for Computational Biology, Rice University, Houston, TX 77251-1892 (United States); Wulff, Michael [European Synchrotron Radiation Facility, BP 220, 38043 Grenoble Cedex (France); Olson, John S. [Department of Biochemistry and Cell Biology, and W.M. Keck Center for Computational Biology, Rice University, Houston, TX 77251-1892 (United States); Anfinrud, Philip A., E-mail: [Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520 (United States)


    Highlights: ► 150-ps Time-resolved Laue crystallography has unveiled ligand dynamics in hemoglobin. ► Significant kinetic differences are observed in the α and β subunits of hemoglobin. ► The B-site lifetime is ∼1.6 ns in β, and ∼18 ns in α. ► The B-site location in β is ∼0.25 Å closer to the binding site than in α. ► The correlation between CO position and rebinding rate suggests distal control. - Abstract: We have developed the method of picosecond Laue crystallography and used this capability to probe ligand dynamics in tetrameric R-state hemoglobin (Hb). Time-resolved, 2 Å-resolution electron density maps of photolyzed HbCO reveal the time-dependent population of CO in the binding (A) and primary docking (B) sites of both α and β subunits from 100 ps to 10 μs. The proximity of the B site in the β subunit is about 0.25 Å closer to its A binding site, and its k{sub BA} rebinding rate (∼300 μs{sup −1}) is six times faster, suggesting distal control of the rebinding dynamics. Geminate rebinding in the β subunit exhibits both prompt and delayed geminate phases. We developed a microscopic model to quantitatively explain the observed kinetics, with three states for the α subunit and four states for the β subunit. This model provides a consistent framework for interpreting rebinding kinetics reported in prior studies of both HbCO and HbO{sub 2}.

  5. Co-overexpression of bacterial GroESL chaperonins partly overcomes non-productive folding and tetramer assembly of E. coli-expressed human medium-chain acyl-CoA dehydrogenase (MCAD) carrying the prevalent disease-causing K304E mutation

    DEFF Research Database (Denmark)

    Bross, P; Andresen, B S; Winter, V;


    underlying MCAD deficiency caused by the prevalent K304E mutation. Depending on which of the three amino acids--lysine (wild-type), glutamic acid (K304E) or glutamine (K304Q) are present at position 304 of the mature polypeptide, three different patterns were observed in our assay system: (i) solubility...... and the enzyme activity measured as observed for the wild-type protein. (iii) Solubility of the K304E mutant is in a similar fashion GroESL responsive as the K304Q mutant, but the amount of tetramer observed and the enzyme activity measured do not correlate with the amount of soluble K304E MCAD protein detected...... in Western blotting. In a first attempt to estimate the specific activity, we show that tetrameric K304E and K304Q mutant MCAD display a specific activity in the range of the wild-type enzyme. Taken together, our results strongly suggest, that the K304E mutation primarily impairs the rate of folding...

  6. Kadar Hemoglobin dan Kecerdasan Intelektual Anak

    Directory of Open Access Journals (Sweden)

    Yuni Kusmiyati


    Full Text Available Kualitas sumber daya manusia dipengaruhi oleh inteligensi anak. Skor kecerdasan intelektual yang tidak menetap pada usia tertentu dapat berubah karena faktor genetik, gizi, dan lingkungan. Tujuan penelitian ini adalah mengetahui hubungan kadar hemoglobin dengan kecerdasan intelektual anak. Penelitian observasional dengan desain potong lintang ini dilakukan pada populasi siswa kelas VI Sekolah Dasar Negeri Giwangan Yogyakarta, tahun 2013. Penarikan sampel dilakukan dengan metode simple random sampling terhadap 37 sampel siswa. Instrumen untuk mengukur kecerdasan intelektual dengan Cultural Fair Intelligence Quotient Test yang dirancang untuk meminimalkan pengaruh kultural dengan memperhatikan prosedur evaluasi, instruksi, konten isi, dan respons peserta. Tes dilakukan oleh Biro Psikologi Universitas Ahmad Dahlan Yogyakarta, kadar hemoglobin diukur menggunakan Portable Hemoglobin Digital Analyzer Easy Touch secara digital.Variabel luar indeks massa tubuh diukur langsung menggunakan parameter tinggi badan dan berat badan. Analisis menggunakan uji regresi linier. Hasil penelitian menunjukkan indeks massa tubuh tidak berhubungan dengan kecerdasan intelektual (nilai p = 0,052. Anemia berhubungan cukup dengan kecerdasan anak (r = 0,491 dan berpola positif, semakin tinggi kadar hemoglobin semakin tinggi kecerdasan intelektual anak. Nilai koefisien determinasi 0,241 menerangkan bahwa 24,1% variasi anemia cukup baik untuk menjelaskan variabel kecerdasan intelektual. Ada hubungan antara kadar hemoglobin dengan kecerdasan intelektual (nilai p = 0,002. Quality of human resources is influenced by the child’s intelligent. Intelligence Quotient (IQ score will not settle at a certain age and can change due to genetic factors, nutrition, and the environment. The objective is known relationship of anemia with IQ to child. Method of observational study with cross sectional design. Population are students of class VI elementary school of Giwangan Yogyakarta in

  7. Radiation-induced tetramer-to-dimer transition of Escherichia coli lactose repressor

    Energy Technology Data Exchange (ETDEWEB)

    Goffinont, S. [Centre de Biophysique Moleculaire, CNRS, rue C. Sadron, 45071 Orleans (France); Davidkova, M. [Department of Radiation Dosimetry, Nuclear Physics Institute AS CR, Na Truhlarce 39/64, 18086, Prague 8 (Czech Republic); Spotheim-Maurizot, M., E-mail: [Centre de Biophysique Moleculaire, CNRS, rue C. Sadron, 45071 Orleans (France)


    The wild type lactose repressor of Escherichia coli is a tetrameric protein formed by two identical dimers. They are associated via a C-terminal 4-helix bundle (called tetramerization domain) whose stability is ensured by the interaction of leucine zipper motifs. Upon in vitro {gamma}-irradiation the repressor losses its ability to bind the operator DNA sequence due to damage of its DNA-binding domains. Using an engineered dimeric repressor for comparison, we show here that irradiation induces also the change of repressor oligomerisation state from tetramer to dimer. The splitting of the tetramer into dimers can result from the oxidation of the leucine residues of the tetramerization domain.

  8. Structural Studies of the Parainfluenza Virus 5 Hemagglutinin-Neuraminidase Tetramer in Complex with Its Receptor, Sialyllactose

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Ping; Thompson, Thomas B.; Wurzburg, Beth A.; Paterson, Reay G.; Lamb, Robert A.; Jardetzky, Theodore S. (NWU)


    The paramyxovirus hemagglutinin-neuraminidase (HN) functions in virus attachment to cells, cleavage of sialic acid from oligosaccharides, and stimulating membrane fusion during virus entry into cells. The structural basis for these diverse functions remains to be fully understood. We report the crystal structures of the parainfluenza virus 5 (SV5) HN and its complexes with sialic acid, the inhibitor DANA, and the receptor sialyllactose. SV5 HN shares common structural features with HN of Newcastle disease virus (NDV) and human parainfluenza 3 (HPIV3), but unlike the previously determined HN structures, the SV5 HN forms a tetramer in solution, which is thought to be the physiological oligomer. The sialyllactose complex reveals intact receptor within the active site, but no major conformational changes in the protein. The SV5 HN structures do not support previously proposed models for HN action in membrane fusion and suggest alternative mechanisms by which HN may promote virus entry into cells.

  9. Concurrent measurement of cellular turbidity and hemoglobin to evaluate the antioxidant activity of plants. (United States)

    Bellik, Yuva; Iguer-Ouada, Mokrane


    In past decades, a multitude of analytical methods for measuring antioxidant activity of plant extracts has been developed. However, when using methods to determine hemoglobin released from human erythrocytes treated with ginger extracts, we found hemoglobin concentrations were significantly higher than in untreated control samples. This suggests in the presence of antioxidants that measuring hemoglobin alone is not sufficient to determine hemolysis. We show concurrent measurement of erythrocyte concentration and hemoglobin is essential in such assays, and describe a new protocol based on simultaneous measurement of cellular turbidity and hemoglobin.

  10. Analysis of Hemoglobin Glycation Using Microfluidic CE-MS: A Rapid, Mass Spectrometry Compatible Method for Assessing Diabetes Management. (United States)

    Redman, Erin A; Ramos-Payan, Maria; Mellors, J Scott; Ramsey, J Michael


    Diabetes has become a significant health problem worldwide with the rate of diagnosis increasing rapidly in recent years. Measurement of glycated blood proteins, particularly glycated hemoglobin (HbA1c), is an important diagnostic tool used to detect and manage the condition in patients. Described here is a method using microfluidic capillary electrophoresis with mass spectrometry detection (CE-MS) to assess hemoglobin glycation in whole blood lysate. Using denaturing conditions, the hemoglobin (Hb) tetramer dissociates into the alpha and beta subunits (α- and β-Hb), which are then separated via CE directly coupled to MS detection. Nearly baseline resolution is achieved between α-Hb, β-Hb, and glycated β-Hb. A second glycated β-Hb isomer that is partially resolved from β-Hb is detected in extracted ion electropherograms for glycated β-Hb. Glycation on α-Hb is also detected in the α-Hb mass spectrum. Additional modifications to the β-Hb are detected, including acetylation and a +57 Da species that could be the addition of a glyoxal moiety. Patient blood samples were analyzed using the microfluidic CE-MS method and a clinically used immunoassay to measure HbA1c. The percentage of glycated α-Hb and β-Hb was calculated from the microfluidic CE-MS data using peak areas generated from extracted ion electropherograms. The values for glycated β-Hb were found to correlate well with the HbA1c levels derived in the clinic, giving a slope of 1.20 and an R(2) value of 0.99 on a correlation plot. Glycation of human serum albumin (HSA) can also be measured using this technique. It was observed that patients with elevated glycated Hb levels also had higher levels of HSA glycation. Interestingly, the sample with the highest HbA1c levels did not have the highest levels of glycated HSA. Because the lifetime of HSA is shorter than Hb, this could indicate a recent lapse in glycemic control for that patient. The ability to assess both Hb and HSA glycation has the potential

  11. MHC class II tetramers made from isolated recombinant α and β chains refolded with affinity-tagged peptides

    DEFF Research Database (Denmark)

    Braendstrup, Peter; Justesen, Sune Frederik Lamdahl; Osterbye, Thomas


    Targeting CD4+ T cells through their unique antigen-specific, MHC class II-restricted T cell receptor makes MHC class II tetramers an attractive strategy to identify, validate and manipulate these cells at the single cell level. Currently, generating class II tetramers is a specialized undertaking...

  12. Non-invasive hemoglobin monitoring. (United States)

    Joseph, Bellal; Haider, Ansab; Rhee, Peter


    Technology has transformed the practice of medicine and surgery in particular over the last several decades. This change in practice has allowed diagnostic and therapeutic tests to be performed less invasively. Hemoglobin monitoring remains one of the most commonly performed diagnostic tests in the United States. Recently, non-invasive hemoglobin monitoring technology has gained popularity. The aim of this article is to review the principles of how this technology works, pros and cons, and the implications of non-invasive hemoglobin technology particularly in trauma surgery.

  13. Concatenated hERG1 tetramers reveal stoichiometry of altered channel gating by RPR-260243. (United States)

    Wu, Wei; Gardner, Alison; Sanguinetti, Michael C


    Activation of human ether-a-go-go-related gene 1 (hERG1) K(+) channels mediates repolarization of action potentials in cardiomyocytes. RPR-260243 [(3R,4R)-4-[3-(6-methoxy-quinolin-4-yl)-3-oxo-propyl]-1-[3-(2,3,5-trifluorophenyl)-prop-2-ynyl]-piperidine-3-carboxylic acid] (RPR) slows deactivation and attenuates inactivation of hERG1 channels. A detailed understanding of the molecular mechanism of hERG1 agonists such as RPR may facilitate the design of more selective and potent compounds for prevention of arrhythmia associated with abnormally prolonged ventricular repolarization. RPR binds to a hydrophobic pocket located between two adjacent hERG1 subunits, and, hence, a homotetrameric channel has four identical RPR binding sites. To investigate the stoichiometry of altered channel gating induced by RPR, we constructed and characterized tetrameric hERG1 concatemers containing a variable number of wild-type subunits and subunits containing a point mutation (L553A) that rendered the channel insensitive to RPR, ostensibly by preventing ligand binding. The slowing of deactivation by RPR was proportional to the number of wild-type subunits incorporated into a concatenated tetrameric channel, and four wild-type subunits were required to achieve maximal slowing of deactivation. In contrast, a single wild-type subunit within a concatenated tetramer was sufficient to achieve half of the maximal RPR-induced shift in the voltage dependence of hERG1 inactivation, and maximal effect was achieved in channels containing three or four wild-type subunits. Together our findings suggest that the allosteric modulation of channel gating involves distinct mechanisms of coupling between drug binding and altered deactivation and inactivation.

  14. High-throughput identification of potential minor histocompatibility antigens by MHC tetramer-based screening

    DEFF Research Database (Denmark)

    Hombrink, Pleun; Hadrup, Sine R; Bakker, Arne;


    MHC-tetramer-based enrichment and multi-color flow cytometry. Using this approach, 71 peptide-reactive T-cell populations were generated. The isolation of a T-cell line specifically recognizing target cells expressing the MAP4K1(IMA) antigen demonstrates that identification of MiHA through this approach is in principle...

  15. Theory vs. experiment for molecular clusters: Spectra of OCS trimers and tetramers

    Energy Technology Data Exchange (ETDEWEB)

    Evangelisti, Luca [Department of Chemistry, University of Virginia, McCormick Road, Charlottesville, Virginia 22904 (United States); Dipartimento di Chimica “G. Ciamician,” University of Bologna, Via Selmi 2, Bologna 40126 (Italy); Perez, Cristobal; Seifert, Nathan A.; Pate, Brooks H. [Department of Chemistry, University of Virginia, McCormick Road, Charlottesville, Virginia 22904 (United States); Dehghany, M.; Moazzen-Ahmadi, N. [Department of Physics and Astronomy, University of Calgary, 2500 University Drive North West, Calgary, Alberta T2N 1N4 (Canada); McKellar, A. R. W. [National Research Council of Canada, Ottawa, Ontario K1A 0R6 (Canada)


    All singly substituted {sup 13}C, {sup 18}O, and {sup 34}S isotopomers of the previously known OCS trimer are observed in natural abundance in a broad-band spectrum measured with a chirped-pulse Fourier transform microwave spectrometer. The complete substitution structure thus obtained critically tests (and confirms) the common assumption that monomers tend to retain their free structure in a weakly bound cluster. A new OCS trimer isomer is also observed, and its structure is determined to be barrel-shaped but with the monomers all approximately aligned, in contrast to the original trimer which is barrel-shaped with two monomers aligned and one anti-aligned. An OCS tetramer spectrum is assigned for the first time, and the tetramer structure resembles an original trimer with an OCS monomer added at the end with two sulfur atoms. Infrared spectra observed in the region of the OCS ν{sub 1} fundamental (≈2060 cm{sup −1}) are assigned to the same OCS tetramer, and another infrared band is tentatively assigned to a different tetramer isomer. The experimental results are compared and contrasted with theoretical predictions from the literature and from new cluster calculations which use an accurate OCS pair potential and assume pairwise additivity.

  16. Tetramer model of leukoemeraldine-emeraldine electrochemistry in the presence of trihalogenoacetic acids. DFT approach. (United States)

    Barbosa, Nuno Almeida; Grzeszczuk, Maria; Wieczorek, Robert


    First results of the application of the DFT computational approach to the reversible electrochemistry of polyaniline are presented. A tetrameric chain was used as the simplest model of the polyaniline polymer species. The system under theoretical investigation involved six tetramer species, two electrons, and two protons, taking part in 14 elementary reactions. Moreover, the tetramer species were interacting with two trihalogenoacetic acid molecules. Trifluoroacetic, trichloroacetic, and tribromoacetic acids were found to impact the redox transformation of polyaniline as shown by cyclic voltammetry. The theoretical approach was considered as a powerful tool for investigating the main factors of importance for the experimental behavior. The DFT method provided molecular structures, interaction energies, and equilibrium energies of all of the tetramer-acid complexes. Differences between the energies of the isolated tetramer species and their complexes with acids are discussed in terms of the elementary reactions, that is, ionization potentials and electron affinities, equilibrium constants, electrode potentials, and reorganization energies. The DFT results indicate a high impact of the acid on the reorganization energy of a particular elementary electron-transfer reaction. The ECEC oxidation path was predicted by the calculations. The model of the reacting system must be extended to octamer species and/or dimeric oligomer species to better approximate the real polymer situation.

  17. Anabaena sp. DyP-type peroxidase is a tetramer consisting of two asymmetric dimers. (United States)

    Yoshida, Toru; Ogola, Henry Joseph Oduor; Amano, Yoshimi; Hisabori, Toru; Ashida, Hiroyuki; Sawa, Yoshihiro; Tsuge, Hideaki; Sugano, Yasushi


    DyP-type peroxidases are a newly discovered family of heme peroxidases distributed from prokaryotes to eukaryotes. Recently, using a structure-based sequence alignment, we proposed the new classes, P, I and V, as substitutes for classes A, B, C, and D [Arch Biochem Biophys 2015;574:49-55]. Although many class V enzymes from eukaryotes have been characterized, only two from prokaryotes have been reported. Here, we show the crystal structure of one of these two enzymes, Anabaena sp. DyP-type peroxidase (AnaPX). AnaPX is tetramer formed from Cys224-Cys224 disulfide-linked dimers. The tetramer of wild-type AnaPX was stable at all salt concentrations tested. In contrast, the C224A mutant showed salt concentration-dependent oligomeric states: in 600 mM NaCl, it maintained a tetrameric structure, whereas in the absence of salt, it dissociated into monomers, leading to a reduction in thermostability. Although the tetramer exhibits non-crystallographic, 2-fold symmetry in the asymmetric unit, two subunits forming the Cys224-Cys224 disulfide-linked dimer are related by 165° rotation. This asymmetry creates an opening to cavities facing the inside of the tetramer, providing a pathway for hydrogen peroxide access. Finally, a phylogenetic analysis using structure-based sequence alignments showed that class V enzymes from prokaryotes, including AnaPX, are phylogenetically closely related to class V enzymes from eukaryotes.

  18. Comparison between alkalimetal and group 11 transition metal halide and hydride tetramers: molecular structure and bonding. (United States)

    El-Hamdi, Majid; Solà, Miquel; Frenking, Gernot; Poater, Jordi


    A comparison between alkalimetal (M = Li, Na, K, and Rb) and group 11 transition metal (M = Cu, Ag, and Au) (MX)4 tetramers with X = H, F, Cl, Br, and I has been carried out by means of the Amsterdam Density Functional software using density functional theory at the BP86/QZ4P level of theory and including relativistic effects through the ZORA approximation. We have obtained that, in the case of alkalimetals, the cubic isomer of Td geometry is more stable than the ring structure with D4h symmetry, whereas in the case of group 11 transition metal tetramers, the isomer with D4h symmetry (or D2d symmetry) is more stable than the Td form. To better understand the results obtained we have made energy decomposition analyses of the tetramerization energies. The results show that in alkalimetal halide and hydride tetramers, the cubic geometry is the most stable because the larger Pauli repulsion energies are compensated by the attractive electrostatic and orbital interaction terms. In the case of group 11 transition metal tetramers, the D4h/D2d geometry is more stable than the Td one due to the reduction of electrostatic stabilization and the dominant effect of the Pauli repulsion.

  19. More Refined Experiments with Hemoglobin. (United States)

    Morin, Phillippe


    Discusses materials needed, procedures used, and typical results obtained for experiments designed to make a numerical stepwise study of the oxygenation of hemoglobin, myoglobin, and other oxygen carriers. (JN)

  20. Nonlinear photoacoustic spectroscopy of hemoglobin

    Energy Technology Data Exchange (ETDEWEB)

    Danielli, Amos; Maslov, Konstantin; Favazza, Christopher P.; Xia, Jun; Wang, Lihong V., E-mail: LHWANG@WUSTL.EDU [Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, St. Louis, Missouri 63130 (United States)


    As light intensity increases in photoacoustic imaging, the saturation of optical absorption and the temperature dependence of the thermal expansion coefficient result in a measurable nonlinear dependence of the photoacoustic (PA) signal on the excitation pulse fluence. Here, under controlled conditions, we investigate the intensity-dependent photoacoustic signals from oxygenated and deoxygenated hemoglobin at varied optical wavelengths and molecular concentrations. The wavelength and concentration dependencies of the nonlinear PA spectrum are found to be significantly greater in oxygenated hemoglobin than in deoxygenated hemoglobin. These effects are further influenced by the hemoglobin concentration. These nonlinear phenomena provide insights into applications of photoacoustics, such as measurements of average inter-molecular distances on a nm scale or with a tuned selection of wavelengths, a more accurate quantitative PA tomography.

  1. Localised IR spectroscopy of hemoglobin

    CERN Document Server

    Yarrow, Fiona


    IR absorption spectroscopy of hemoglobin was performed using an IR optical parametric oscillator laser and a commercial atomic force microscope in a novel experimental arrangement based on the use of a bottom-up excitation alignment. This experimental approach enables detection of protein samples with a resolution that is much higher than that of standard IR spectroscopy. Presented here are AFM based IR absorption spectra of micron sized hemoglobin features


    Directory of Open Access Journals (Sweden)



    Full Text Available An outer sphere electron transfer mechanism by which human hemoglobin reduces the complexes of copper(II and, in turn, is oxidized to methemoglobin has been characterized. We have found that the rate of oxidation of hemoglobin is a function of pH, temperature, concentration of copper(II, and the environment of the hemoglobin. Prior to oxidation, copper(II complex binds to specific sites on the surface of the protein by losing one or more of its ligands, forming a ternary complex. This process is followed by electron transfer between the Cu(II and Fe(H with the Cu(II-deoxyhemoglobin being the active intermediate. The dominant factors which govern the rate of oxidation of hemoglobin by coppcr(I I complexes seem to be the stability constant of the Cu(II complexes and the overall redox potential of the ternary complex.

  3. Perturbation of the Monomer-Monomer Interfaces of the Benzoylformate Decarboxylase Tetramer

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, Forest H.; Rogers, Megan P.; Paul, Lake N.; McLeish, Michael J. [IUPUI; (Purdue)


    The X-ray structure of benzoylformate decarboxylase (BFDC) from Pseudomonas putida ATCC 12633 shows it to be a tetramer. This was believed to be typical of all thiamin diphosphate-dependent decarboxylases until recently when the structure of KdcA, a branched-chain 2-keto acid decarboxylase from Lactococcus lactis, showed it to be a homodimer. This lent credence to earlier unfolding experiments on pyruvate decarboxylase from Saccharomyces cerevisiae that indicated that it might be active as a dimer. To investigate this possibility in BFDC, we sought to shift the equilibrium toward dimer formation. Point mutations were made in the noncatalytic monomer–monomer interfaces, but these had a minimal effect on both tetramer formation and catalytic activity. Subsequently, the R141E/Y288A/A306F variant was shown by analytical ultracentrifugation to be partially dimeric. It was also found to be catalytically inactive. Further experiments revealed that just two mutations, R141E and A306F, were sufficient to markedly alter the dimer–tetramer equilibrium and to provide an ~450-fold decrease in kcat. Equilibrium denaturation studies suggested that the residual activity was possibly due to the presence of residual tetramer. The structures of the R141E and A306F variants, determined to <1.5 Å resolution, hinted that disruption of the monomer interfaces will be accompanied by movement of a loop containing Leu109 and Leu110. As these residues contribute to the hydrophobicity of the active site and the correct positioning of the substrate, it seems that tetramer formation may well be critical to the catalytic activity of BFDC.

  4. IPR and technological issues regarding a biopharmaceutical formulation hemoglobin. (United States)

    Honrao, Chandrashekhar; Banerjee, Uttam C; Bansal, Parikshit


    Hemoglobin, the protein responsible for the red color of blood plays a very important part in 'life'- it transports oxygen, without which humans cannot survive. The idea of using purified Hemoglobin as a possible universal substitute for red blood cells has been around for almost a century. Hemoglobin formulations have important therapeutic applications, especially in case of trauma and war when requirements for blood may be very large. Manufacture of hemoglobin for use as a biopharmaceutical poses practical challenges, owing to dependence on human expired blood and fragility of the protein molecule. Biotechnology can play a critical role in breaking these barriers, by not only ensuring recombinant production of hemoglobin, but also enhancing stability of the molecule. The present article, based on a review of patents and available literature gives an insight into the IPR and technological issues involved in the commercial production of this 'life-saving' protein. There are more than 250 patents worldwide related to hemoglobin formulation, cross-linking and determination.

  5. Tangential flow filtration of hemoglobin. (United States)

    Palmer, Andre F; Sun, Guoyong; Harris, David R


    Bovine and human hemoglobin (bHb and hHb, respectively) was purified from bovine and human red blood cells via tangential flow filtration (TFF) in four successive stages. TFF is a fast and simple method to purify Hb from RBCs using filtration through hollow fiber (HF) membranes. Most of the Hb was retained in stage III (100 kDa HF membrane) and displayed methemoglobin levels less than 1%, yielding final concentrations of 318 and 300 mg/mL for bHb and hHb, respectively. Purified Hb exhibited much lower endotoxin levels than their respective RBCs. The purity of Hb was initially assessed via SDS-PAGE, and showed tiny impurity bands for the stage III retentate. The oxygen affinity (P(50)) and cooperativity coefficient (n) were regressed from the measured oxygen-RBC/Hb equilibrium curves of RBCs and purified Hb. These results suggest that TFF yielded oxygen affinities of bHb and hHb that are comparable to values in the literature. LC-MS was used to measure the molecular weight of the alpha (alpha) and beta (beta) globin chains of purified Hb. No impurity peaks were present in the HPLC chromatograms of purified Hb. The mass of the molecular ions corresponding to the alpha and beta globin chains agreed well with the calculated theoretical mass of the alpha- and beta- globin chains. Taken together, our results demonstrate that HPLC-grade Hb can be generated via TFF. In general, this method can be more broadly applied to purify Hb from any source of RBCs. This work is significant, since it outlines a simple method for generating Hb for synthesis and/or formulation of Hb-based oxygen carriers.

  6. AltitudeOmics: rapid hemoglobin mass alterations with early acclimatization to and de-acclimatization from 5260 m in healthy humans. (United States)

    Ryan, Benjamin J; Wachsmuth, Nadine B; Schmidt, Walter F; Byrnes, William C; Julian, Colleen G; Lovering, Andrew T; Subudhi, Andrew W; Roach, Robert C


    It is classically thought that increases in hemoglobin mass (Hbmass) take several weeks to develop upon ascent to high altitude and are lost gradually following descent. However, the early time course of these erythropoietic adaptations has not been thoroughly investigated and data are lacking at elevations greater than 5000 m, where the hypoxic stimulus is dramatically increased. As part of the AltitudeOmics project, we examined Hbmass in healthy men and women at sea level (SL) and 5260 m following 1, 7, and 16 days of high altitude exposure (ALT1/ALT7/ALT16). Subjects were also studied upon return to 5260 m following descent to 1525 m for either 7 or 21 days. Compared to SL, absolute Hbmass was not different at ALT1 but increased by 3.7 ± 5.8% (mean ± SD; n = 20; pcell destruction. Our novel findings demonstrate that Hbmass increases within 7 days of ascent to 5260 m but that the altitude-induced Hbmass adaptation is lost within 7 days of descent to 1525 m. The rapid time course of these adaptations contrasts with the classical dogma, suggesting the need to further examine mechanisms responsible for Hbmass adaptations in response to severe hypoxia.

  7. Glucocorticoid treatment skews human monocyte differentiation into a hemoglobin-clearance phenotype with enhanced heme-iron recycling and antioxidant capacity. (United States)

    Vallelian, Florence; Schaer, Christian A; Kaempfer, Theresa; Gehrig, Peter; Duerst, Elena; Schoedon, Gabriele; Schaer, Dominik J


    Glucocorticoids are used extensively to treat autoimmune hemolytic anemias. Some beneficial effects of glucocorticoid pulse therapy have also been reported in sickle cell disease and paroxysmal nocturnal hemoglobinuria. Based on established concepts of hemoglobin (Hb) toxicity and physiologic Hb scavenger systems, we evaluated whether glucocorticoids could support an adaptive response to extracellular Hb independently of their immunosuppressive activities. Using global proteome and transcriptome analysis with mass-spectrometry (isobaric tag for relative and absolute quantitation and liquid chromatography-mass spectrometry) and gene-array experiments, we found that glucocorticoid treatment in vitro and in patients on glucocorticoid-pulse therapy polarized monocytes into a M2/alternatively activated phenotype with high Hb-scavenger receptor (CD163) expression and enhanced Hb-clearance and detoxification capability. Monocytes concurrently exposed to the interactive activity of glucocorticoids and extracellular Hb were characterized by high expression of a group of antioxidant enzymes known to be regulated by the conserved oxidative response transcription factor nuclear factor E2-related factor. Further, suppressed transferrin receptor, together with high ferroportin expression, pointed to a shift in iron homeostasis directed toward an increased cellular export of heme-derived iron. Therefore, stimulating Hb-endocytosis by CD163 and enhancing antioxidative homeostasis and iron recycling may be an essential activity of glucocorticoids that helps alleviate the adverse effects of extracellular Hb.

  8. Effects of maleimide-polyethylene glycol-modified human hemoglobin (MP4 on tissue necrosis in SKH1-hr hairless mice

    Directory of Open Access Journals (Sweden)

    Goertz O


    Full Text Available Abstract Objective Tissue hypoxia after blood loss, replantation and flap reperfusion remains a challenging task in surgery. Normovolemic hemodilution improves hemorheologic properties without increasing oxygen carrying capacity. Red blood cell transfusion is the current standard of treatment with its attendant risks. The aim of this study was to investigate the potential of the chemically modified hemoglobin, MP4, to reduce skin flap necrosis and its effect on selected blood markers and kidneys. Materials and methods Tissue ischemia was induced in the ear of hairless mice (n = 26. Hemodilution was performed by replacing one third of blood volume with the similar amount of MP4, dextran, or blood. The extent of non-perfused tissue was assessed by intravital fluorescent microscopy. Results Of all groups, MP4 showed the smallest area of no perfusion (in percentage of the ear ± SEM: 16.3% ± 2.4, the control group the largest (22.4% ± 3.5. Leukocytes showed a significant increase in the MP4 and dextran group (from 8.7 to 13.6 respectively 15.4*109/l. On histology no changes of the kidneys could be observed. Conclusion MP4 causes an increase of leukocytes, improves the oxygen supply of the tissue and shows no evidence of renal impairment.

  9. Thymidine kinase 1 regulatory fine-tuning through tetramer formation

    DEFF Research Database (Denmark)

    Mutahir, Zeeshan; Clausen, Anders R.; Andersson, Karl-Magnus;


    Abstract: Thymidine kinase 1 (TK1) provides a crucial precursor, deoxythymidine monophosphate, for nucleic acid synthesis, and the activity of TK1 increases by up to 200-fold during the S-phase of cell division in humans. An important part of the regulatory checkpoints is the ATP and enzyme...

  10. Many-body forces and stability of the alkaline-earth tetramers

    Energy Technology Data Exchange (ETDEWEB)

    Diaz-Torrejon, C.C. [Centro Nacional de Supercomputo, IPICyT, A.C., Camino a la Presa San Jose 2055, 78216 San Luis Potosi, SLP (Mexico); Centro de Investigacion en Materiales Avanzados, S.C., Av. Miguel de Cervantes 120, 31109 Chihuahua, Chih. (Mexico); Kaplan, Ilya G., E-mail: [Instituto de Investigaciones en Materiales, UNAM, Apdo. Postal 70-360, 04510 Mexico D.F. (Mexico)


    Graphical abstract: Many-body forces effect. In a three-particle system, the two-body interaction energies depend upon coordinates of all three particles. The comparative study of the interaction energy and its many-body decomposition for alkaline-earths tetramers Be{sub 4}, Mg{sub 4}, and Ca{sub 4} at the all-electron CCSD(T)/aug-cc-pVQZ level is performed. For study of dependence of the binding energy and the orbital population on the cluster size the corresponding dimers and trimers were also calculated at the same level of theory. In comparison with weakly bound dimers, the binding energy in trimers and, especially, in tetramers drastically increases; e.g., E{sub b}/N in Be{sub 3} is 7 times larger and in Be{sub 4} is 18.4 times larger than in Be{sub 2}. This sharp increase is explained as a manifestation of many-body forces. The trimers and tetramers are stabilized by the three-body forces, whereas the two- and four-body forces are repulsive. The attractive contribution to the three-body forces has a three-atom electron exchange origin. The natural bond orbital (NBO) population analysis reveals a relatively large np-population in trimers and tetramers. The population of the valence np-orbitals leads to the sp-hybridization providing the covalent bonding. Research highlights: {yields} The alkaline-earths trimers and tetramers are stabilized by the three-body forces. {yields} Two- and four-body forces are repulsive for trimers and tetramers. {yields} The attractive contribution to the three-body forces has a three-atom electron exchange origin. {yields} The population of the np-orbitals leads to the sp-hybridization providing the covalent bonding. - Abstract: The comparative study of the interaction energy and its many-body decomposition for Be{sub 4}, Mg{sub 4}, and Ca{sub 4} at the all-electron CCSD(T)/aug-cc-pVQZ level is performed. For study of dependence of the binding energy and the orbital population on the cluster size the corresponding dimers and

  11. Tetrabromobisphenol A Is an Efficient Stabilizer of the Transthyretin Tetramer.

    Directory of Open Access Journals (Sweden)

    Irina Iakovleva

    Full Text Available Amyloid formation of the human plasma protein transthyretin (TTR is associated with several human disorders, including familial amyloidotic polyneuropathy (FAP and senile systemic amyloidosis. Dissociation of TTR's native tetrameric assembly is the rate-limiting step in the conversion into amyloid, and this feature presents an avenue for intervention because binding of an appropriate ligand to the thyroxin hormone binding sites of TTR stabilizes the native tetrameric assembly and impairs conversion into amyloid. The desired features for an effective TTR stabilizer include high affinity for TTR, high selectivity in the presence of other proteins, no adverse side effects at the effective concentrations, and a long half-life in the body. In this study we show that the commonly used flame retardant tetrabromobisphenol A (TBBPA efficiently stabilizes the tetrameric structure of TTR. The X-ray crystal structure shows TBBPA binding in the thyroxine binding pocket with bromines occupying two of the three halogen binding sites. Interestingly, TBBPA binds TTR with an extremely high selectivity in human plasma, and the effect is equal to the recently approved drug tafamidis and better than diflunisal, both of which have shown therapeutic effects against FAP. TBBPA consequently present an interesting scaffold for drug design. Its absorption, metabolism, and potential side-effects are discussed.

  12. The body-centered cubic structure of methyllithium tetramer crystal: staggered methyl conformation by electrostatic stabilization via intratetramer multipolarization. (United States)

    Ohta, Yusuke; Demura, Akimitsu; Okamoto, Takuya; Hitomi, Haruko; Nagaoka, Masataka


    The methyllithium tetramer (CH3Li)4 structure in the bcc crystal has been theoretically optimized with the use of density functional theory calculations under the periodic boundary condition. The X-ray structure shows that the methyl-group conformation in tetramer in crystal takes the staggered form rather than the eclipsed form that is taken in the isolated tetramer, i.e., the crystal packing effect, and this has been reproduced for the first time. It is concluded that the staggered form is advantageous in crystal, as a whole, due to the larger electrostatic stabilization via the induced intratetramer multipolarization, although it should cause, simultaneously, smaller destabilization in intratetramer electronic energy.

  13. Reactions of arsine with hemoglobin

    Energy Technology Data Exchange (ETDEWEB)

    Hatlelid, K.M.; Brailsford, C.; Carter, D.E. [Univ. of Arizona, Tucson, AZ (United States)


    The mechanism of arsine (AsH{sub 3}) induced hemolysis was studied in vitro using isolated red blood cells (RBCs) from the rat or dog. AsH{sub 3}-induced hemolysis of dog red blood cells was completely blocked by carbon monoxide (CO) preincubation and was reduced by pure oxygen (O{sub 2}) compared to incubations in air. Since CO and O{sub 2} bind to heme and also reduced hemolysis, these results suggested a reaction between AsH{sub 3} and hemoglobin in the hemeligand binding pocket or with the heme iron. Further, sodium nitrite induction of methemoglobin (metHb) to 85% and 34% of total Hb in otherwise intact RBCs resulted in 56% and 16% decreases in hemolysis, respectively, after incubation for 4 h. This provided additional evidence for the involvement of hemoglobin in the AsH{sub 3}-induced hemolysis mechanism. Reactions between AsH{sub 3} and hemoglobin were studied in solutions of purified dog hemoglobin. Spectrophotometric studies of the reaction of AsH{sub 3} with various purified hemoglobin species revealed that AsH{sub 3} reacted with HbO{sub 2} to produce metHb and, eventually, degraded Hb characterized by gross precipitation of the protein. AsH{sub 3} did not alter the spectrum of deoxyHb and did not cause degradation of metHb in oxygen, but bound to and reduced metHb in the absence of oxygen. These data indicate that a reaction of AsH{sub 3} with oxygenated hemoglobin, HbO{sub 2}, may lead to hemolysis, but there are reactions between AsH{sub 3} and metHb that may not be directly involved in the hemolytic process. 17 refs., 6 figs.

  14. Oligomers Based on a Weak Hydrogen Bond Network: the Rotational Spectrum of the Tetramer of Difluoromethane (United States)

    Feng, Gang; Evangelisti, Luca; Caminati, Walther; Cacelli, Ivo; Carbonaro, Laura; Prampolini, Giacomo


    Following the investigation of the rotational spectra of three conformers (so-called ``book'', ``prism'' and ``cage'') of the water hexamer, and of some other water oligomers, we report here the rotational spectrum of the tetramer of a freon molecule. The pulse jet Fourier transform microwave (pj-FTMW) spectrum of an isomer of the difluoromethane tetramer has been assigned. This molecular system is made of units of a relatively heavy asymmetric rotor, held together by a network of weak hydrogen bonds. The search of the rotational spectrum has been based on a high-level reference method, the CCSD(T)/CBS protocol. It is interesting to outline that the rotational spectrum of the water tetramer was not observed, probably because the minimum energy structures of this oligomer is effectively nonpolar in its ground states, or because of high energy tunnelling splittings. The rotational spectra of the monomer, dimer, trimer and tetramer of difluoromethane have been assigned in 1952, 1999, 2007, and 2013 (present work), with a decreasing time spacing between the various steps, looking then promising for a continuous and rapid extension of the size limits of molecular systems accessible to MW spectroscopy. C. Pérez, M. T. Muckle, D. P. Zaleski, N. A. Seifert, B. Temelso, G. C. Shields, Z. Kisiel, B. H. Pate, Science {336} (2012) 897. D. R. Lide, Jr., J. Am. Chem. Soc. {74} (1952) 3548. W. Caminati, S. Melandri, P. Moreschini, P. G. Favero, Angew. Chem. Int. Ed. {38} (1999) 2924. S. Blanco, S. Melandri, P. Ottaviani, W. Caminati, J. Am. Chem. Soc. {129} (2007) 2700.

  15. Chirped-Pulse Broadband Microwave Spectra and Structures of the OCS Trimer and Tetramer (United States)

    Evangelisti, Luca; Perez, Cristobal; Seifert, Nathan A.; Pate, Brooks; Dehghany, Mehdi; Moazzen-Ahmadi, Nasser; McKellar, Bob


    Structure determination of weakly bound OCS clusters is a challenging problem due to many low energy isomers on the potential energy surface. The premier tool for studying these clusters is high-resolution infrared spectroscopy, as it can be used to analyze non-polar clusters. Following the analysis of high-resolution IR spectra of clusters formed in a molecular beam expansion of OCS there were some outstanding questions about the structures of the observed clusters. The chirped-pulse Fourier transform microwave spectrum in the 3-9 GHz frequency range was measured for a pulsed molecular beam of OCS in neon (1%). All 13C, 18O and 34S isotopologues of the previously detected OCS trimer have been observed in natural abundance in the 3-9 GHz band using chirped-pulse Fourier transform microwave spectroscopy. The structure of this trimer features a barrel-shaped structure with two aligned and one anti-aligned OCS monomers. A new OCS trimer is also observed for the first time, and its structure is consistent with a barrel-shaped structure with 3 aligned monomers. Using the infrared spectrum for guidance, a spectrum corresponding to a polar OCS tetramer has been assigned. This cluster has a similar barrel-like structure but with an additional tilted OCS monomer added to the top of the barrel. All 13C and 34S isotopologues have been assigned for the tetramer. However, due to sign ambiguities in Kraitchman's equations, and small rotational constant differences between aligned and anti-aligned combinations of OCS molecules in the trimer barrel, absolute structural assignment is indeterminate without additional constraints. Therefore a combinatoric approach was used to compute the most reasonable tetramer structure using distance and sign constraints between pairs of carbon and sulfur coordinates, assuming the experimental OCS monomer structure. Results of this approach will be presented, as well as a comparison of the experimental results with the most recent ab initio

  16. A Symmetrical Tetramer for S. aureus Pyruvate Carboxylase in Complex with Coenzyme A

    Energy Technology Data Exchange (ETDEWEB)

    Yu, L.; Xiang, S; Lasso, G; Gil, D; Valle, M; Tong, L


    Pyruvate carboxylase (PC) is a conserved metabolic enzyme with important cellular functions. We report crystallographic and cryo-electron microscopy (EM) studies of Staphylococcus aureus PC (SaPC) in complex with acetyl-CoA, an allosteric activator, and mutagenesis, biochemical, and structural studies of the biotin binding site of its carboxyltransferase (CT) domain. The disease-causing A610T mutation abolishes catalytic activity by blocking biotin binding to the CT active site, and Thr908 might play a catalytic role in the CT reaction. The crystal structure of SaPC in complex with CoA reveals a symmetrical tetramer, with one CoA molecule bound to each monomer, and cryo-EM studies confirm the symmetrical nature of the tetramer. These observations are in sharp contrast to the highly asymmetrical tetramer of Rhizobium etli PC in complex with ethyl-CoA. Our structural information suggests that acetyl-CoA promotes a conformation for the dimer of the biotin carboxylase domain of PC that might be catalytically more competent.

  17. Dynamic Covalent Synthesis of Aryleneethynylene Cages through Alkyne Metathesis: Dimer, Tetramer, or Interlocked Complex?

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Qi; Yu, Chao; Zhang, Chenxi; Long, Hai; Azarnoush, Setareh; Jin, Yinghua; Zhang, Wei


    A dynamic covalent approach towards rigid aryleneethynylene covalent organic polyhedrons (COPs) was explored. Our study on the relationship of the COP structures and the geometry of their building blocks reveals that the topology of aryleneethynylene COPs strongly depends on the size of the building blocks. A tetramer (D2h symmetric), dimer, or interlocked complex can be formed from monomers with the same face-to-edge angle but in different sizes. As alkyne metathesis is a self-exchange reaction and non-directional, the cyclooligomerization of multi-alkyne monomers involves both intramolecular cyclization and intermolecular metathesis reaction, resulting in complicated thermodynamic process disturbed by kinetic competition. Although a tetrahedron-shaped tetramer (Td symmetric) has comparable thermodynamic stability to a D2h symmetric tetramer, its formation is kinetically disfavored and was not observed experimentally. Aryleneethynylene COPs consist of purely unsaturated carbon backbones and exhibit large internal cavities, which would have interesting applications in host-guest chemistry and development of porous materials.

  18. Dimer-tetramer transition between solution and crystalline states of streptavidin and avidin mutants. (United States)

    Pazy, Yael; Eisenberg-Domovich, Yael; Laitinen, Olli H; Kulomaa, Markku S; Bayer, Edward A; Wilchek, Meir; Livnah, Oded


    The biotin-binding tetrameric proteins, streptavidin from Streptomyces avidinii and chicken egg white avidin, are excellent models for the study of subunit-subunit interactions of a multimeric protein. Efforts are thus being made to prepare mutated forms of streptavidin and avidin, which would form monomers or dimers, in order to examine their effect on quaternary structure and assembly. In the present communication, we compared the crystal structures of binding site W-->K mutations in streptavidin and avidin. In solution, both mutant proteins are known to form dimers, but upon crystallization, both formed tetramers with the same parameters as the native proteins. All of the intersubunit bonds were conserved, except for the hydrophobic interaction between biotin and the tryptophan that was replaced by lysine. In the crystal structure, the binding site of the mutated apo-avidin contains 3 molecules of structured water instead of the 5 contained in the native protein. The lysine side chain extends in a direction opposite that of the native tryptophan, the void being partially filled by an adjacent lysine residue. Nevertheless, the binding-site conformation observed for the mutant tetramer is an artificial consequence of crystal packing that would not be maintained in the solution-phase dimer. It appears that the dimer-tetramer transition may be concentration dependent, and the interaction among subunits obeys the law of mass action.

  19. A tri state mechanism for oxygen release in fish hemoglobin: Using Barbus sharpeyi as a model

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Dayer


    Full Text Available Hemoglobin is a porphyrin containing protein with an a2b2 tetrameric structure and like other porphyrin compounds shows spectral behavior of species specific characteristics. Researchers tend to relate bands in the hemoglobin spectra to certain structural and/or functional features. Given the fact that hemoglobin is the main oxygen carrier in animals functioning through the Oxy«Deoxy equilibrium, the determination of oxy and deoxy conformations of hemoglobins of different animals may shed light on their oxygen binding properties. Absorption spectra at 280 and 373nm have been widely used to quantitate the formation of hemoglobin deoxy conformation. In the present work, however, we used an optical density ratio of OD373/OD280 as an index for deoxy formation. This ratio was determined for Barbus sharpeyi and human hemoglobins at different SDS concentrations, pH levels and temperatures to compare them from a structure-function point of view. Our data showed that under low concentrations of SDS (Barbus sharpeyi hemoglobin folds in a tri-state pattern while human hemoglobin folds through a two-state phenomenon. This finding indicates that in contrast to those of other non aquatic animals, the hemoglobin of Barbus sharpeyi has a loosely folded tetrameric structure with remarkably more oxygen affinity

  20. Hemoglobin allostery: new views on old players. (United States)

    Miele, Adriana Erica; Bellelli, Andrea; Brunori, Maurizio


    Proteins are dynamic molecular machines whose structure and function are modulated by environmental perturbations and natural selection. Allosteric regulation, discovered in 1963 as a novel molecular mechanism of enzymatic adaptation [Monod, Changeux & Jacob (1963). J. Mol. Biol.6, 306-329], seems to be the leit motiv of enzymes and metabolic pathways, enabling fine and quick responses toward external perturbations. Hemoglobin (Hb), the oxygen transporter of all vertebrates, has been for decades the paradigmatic system to test the validity of the conformational selection mechanism, the conceptual innovation introduced by Monod, Wyman and Changeux. We present hereby the results of a comparative analysis of structure, function and thermodynamics of two extensively investigated hemoglobins: human HbA and trout HbI. They represent a unique and challenging comparison to test the general validity of the stereochemical model proposed by Perutz. Indeed both proteins are ideal for the purpose being very similar yet very different. In fact, T-HbI is a low-ligand-affinity cooperative tetrameric Hb, insensitive to all allosteric effectors. This remarkable feature, besides being physiologically sound, supports the stereochemical model, given that the six residues identified in HbA as responsible for the Bohr and the 2,3-di-phosphoglycerate effects are all mutated. Comparison of the three-dimensional structures of HbA and T-HbI allows unveiling the molecular mechanism whereby the latter has a lower O2 affinity. Moreover, the energetic balance sheet shows that the salt bridges breaking upon allosteric quaternary transition are important yet insufficient to account for the free energy of heme-heme interactions in both hemoglobins.

  1. Blood Test: Hemoglobin A1C (United States)

    ... 2014 previous 1 • 2 • 3 For Teens For Kids For Parents MORE ON THIS TOPIC Diabetes Control: Why It's Important Monitoring Blood Sugar Helping Kids Deal With Injections and Blood Tests Blood Test: Hemoglobin ... Center Word! Glycosylated Hemoglobin Test (Hemoglobin A1c) Medical ...

  2. Allylation of intraerythrocytic hemoglobin by raw garlic extracts. (United States)

    Bonaventura, Joseph; Rodriguez, Eva N; Beyley, Veronica; Vega, Irving E


    Recent studies have shown that deoxygenated human red blood cells (RBCs) converted garlic-derived polysulfides into hydrogen sulfide, which in turn produced vasorelaxation in aortic ring preparations. The vasoactivity was proposed to occur via glucose- and thiol-dependent acellular reactions. In the present study, we investigated the interaction of garlic extracts with human deoxygenated RBCs and its effect on intracellular hemoglobin molecules. The results showed that garlic extract covalently modified intraerythrocytic deoxygenated hemoglobin. The modification identified consisted of an addition of 71 atomic mass units, suggesting allylation of the cysteine residues. Consistently, purified human deoxyhemoglobin reacted with chemically pure diallyl disulfide, showing the same modification as garlic extracts. Tandem mass spectrometry analysis demonstrated that garlic extract and diallyl disulfide modified hemoglobin's beta-chain at cysteine-93 (beta-93C) or cysteine-112 (beta-112C). These results indicate that garlic-derived organic disulfides as well as pure diallyl disulfide must permeate the RBC membrane and modified deoxyhemoglobin at beta-93C or beta-112C. Although the physiological role of the reported garlic extract-induced allyl modification on human hemoglobin warrants further study, the results indicate that constituents of natural products, such as those from garlic extract, modify intracellular proteins.

  3. Effects of exposure of blood hemoglobin to nitric oxide

    Energy Technology Data Exchange (ETDEWEB)

    Chiodi, H.; Mohler, J.G.


    The effect of oxygen exposure on nitrosythemoglobin of whole human blood or its buffered solution has been determined. The amount of methemoglobin formed was determined by anaerobic modification of the Evelyn-Malloy method: 59% of the total hemoglobin of whole blood was oxidized to methemoglobin in the first 15 min of the oxygen exposure and 78% of the total hemoglobin was oxidized after 120 min of oxygen exposure. Similar results were obtained when nitrosylhemoglobin buffered solutions were exposed to the oxygen of the air. A comparison of the present in vitro results with these obtained by injecting nitric oxide into the rat peritoneal cavity and its implications are discussed.

  4. Assembly processes in oligomers containing structurally distinct subunits. [Hemoglobin, Hemocyanin

    Energy Technology Data Exchange (ETDEWEB)

    Bonaventura, C. (Duke Univ. Marine Laboratory, Beaufort, NC); Bonaventura, J.; Brouwer, M.


    There are two major classes of oxygen carrying proteins: the hemoglobins and the hemocyanins. Thetrameric hemoglobin is an oxygen carrier that has long served as a model in the analysis of allostery in proteins. In assembly processes as well, the oxygen carrying proteins appear to be good model systems which illustrate the distinct roles played by structurally diverse subunits. Thetrameric human hemoglobin shows definite differences in assembly and tetrameric stability depending on alpha-beta, alpha-alpha, beta-beta, alpha-gamma, etc., interactions. The blue-colored hemocyanins are found in the hemolymph of many molluscs and arthropods. In these molecules, oxygen binds at dimeric copper centers. Te reactivity toward oxygen is typically modulated by external factors such as pH and sodium chloride. Because of their extremely large size and subunit diversity, the hemocyanins may be particularly useful as assembly models.

  5. Switching from human insulin to biphasic insulin aspart 30 treatment gets more patients with type 2 diabetes to reach target glycosylated hemoglobin 《7%: the results from the China cohort of the PRESENT study

    Institute of Scientific and Technical Information of China (English)

    GAO Yan; GUO Xiao-hui


    Background The clinical importance of glycaemic control in patients with diabetes has been well established. This study aimed to explore twice-daily biphasic insulin aspart 30 (BIAsp 30) for insulin initiation in patients with type 2 diabetes mellitus (T2DM) who had poor glycaemic control with human insulins (His). We use data from a Chinese cohort of the PRESENT study.Methods In the 3-month study, Chinese subjects with T2DM started insulin therapy with BIAsp 30 in routine care. Glycaemic control was measured by glycosylated hemoglobin (HbA1c), fasting plasma glucose (FPG) and posting plasma glucose (PPG). The safety assessment included hypoglycaemia and other adverse events.Results A total of 1989 subjects previously treated with His were switched to BIAsp 30 for 3-month treatment. Mean HbA1c, FPG and PPG were significantly improved after the therapy. The overall rate of hypoglycaemia decreased at the end of the trial except for the patients previously treated with long-acting insulin. Most of the events were minor and diurnal hypoglycaemia. Only one serious adverse drug reaction (SADR), a local hypersensitivity, was reported. The majority of the patients (296.7%) and physicians (≥84.7%) were either satisfied or very satisfied with the treatment using BIAsp 30 compared with previous HI therapy.Conclusion The BIAsp 30 treatment improved both glycaemic control and patients' satisfaction without increasing hypoglycaemia in T2DM subjects inadequately controlled by Hls.

  6. 7-Chloro-4-aminoquinoline γ-hydroxy-γ-lactam derived-tetramates as a new family of antimalarial compounds. (United States)

    Chopin, Nicolas; Iikawa, Shinya; Bosson, Julien; Lavoignat, Adeline; Bonnot, Guillaume; Bienvenu, Anne-Lise; Picot, Stéphane; Bouillon, Jean-Philippe; Médebielle, Maurice


    In this Letter we report on an efficient and short 2-3 steps synthesis of γ-hydroxy-γ-lactam derived-tetramates bearing a 7-chloro-4-aminoquinoline skeleton and their evaluation as potent antimalarials. These molecules were obtained through ring opening-ring closure (RORC) process of γ-ylidene-tetronate derivatives in the presence of 7-chloro-4-aminoquinoline-derived amines. In vitro antimalarial activity of these new γ-lactams was evaluated against Plasmodium falciparum clones of variable sensitivity (3D7 and W2) and they were found to be active in the range of 14-827nM with generally good resistance index. A preliminary SAR study is also presented to explain these results. Finally, the most active compounds did not show in vitro cytotoxicity when tested against Human Umbilical Vein Endothelial Cells (HUVEC) up to concentration of 50μM and they were stable at pH 7.4 for at least 48h.

  7. Crystal Structure of α-Galactosidase from Lactobacillus acidophilus NCFM: Insight into Tetramer Formation and Substrate Binding

    DEFF Research Database (Denmark)

    Fredslund, Folmer; Abou Hachem, Maher; Larsen, Rene Jonsgaard


    Lactobacillus acidophilus NCFM is a probiotic bacterium known for its beneficial effects on human health. The importance of α-galactosidases (α-Gals) for growth of probiotic organisms on oligosaccharides of the raffinose family present in many foods is increasingly recognized. Here, the crystal...... structure of α-Gal from L. acidophilus NCFM (LaMel36A) of glycoside hydrolase (GH) family 36 (GH36) is determined by single-wavelength anomalous dispersion. In addition, a 1.58-Å-resolution crystallographic complex with α-d-galactose at substrate binding subsite −1 was determined. LaMel36A has a large N......-terminal twisted β-sandwich domain, connected by a long α-helix to the catalytic (β/α)8-barrel domain, and a C-terminal β-sheet domain. Four identical monomers form a tightly packed tetramer where three monomers contribute to the structural integrity of the active site in each monomer. Structural comparison of La...

  8. O-Raffinose Crosslinking Substantially Ameliorates the Vasoconstrictive and Nitric-Oxide-Inactivating Effects of Unmodified Human Hemoglobin in the Rat (United States)


    acetylsalicylic acid or any other platelet inhibitor for at least seven days. The first 2 mL of blood drawn were discarded. Blood was then drawn into...The bovine endothelial cell-coated beads (ECBs) were exposed to 30 pM acetylsalicylic acid for 1 h at 37°C to inhibit cyclooxygenase activity and...Human serum albumin, sodium nitrite, trichloroacetic acid , trypan blue, Sepharose 2B, adenosine 5’-diphosphate (ADP), glutathione (GSH) and N(D-nitro

  9. First structure of full-length mammalian phenylalanine hydroxylase reveals the architecture of an autoinhibited tetramer. (United States)

    Arturo, Emilia C; Gupta, Kushol; Héroux, Annie; Stith, Linda; Cross, Penelope J; Parker, Emily J; Loll, Patrick J; Jaffe, Eileen K


    Improved understanding of the relationship among structure, dynamics, and function for the enzyme phenylalanine hydroxylase (PAH) can lead to needed new therapies for phenylketonuria, the most common inborn error of amino acid metabolism. PAH is a multidomain homo-multimeric protein whose conformation and multimerization properties respond to allosteric activation by the substrate phenylalanine (Phe); the allosteric regulation is necessary to maintain Phe below neurotoxic levels. A recently introduced model for allosteric regulation of PAH involves major domain motions and architecturally distinct PAH tetramers [Jaffe EK, Stith L, Lawrence SH, Andrake M, Dunbrack RL, Jr (2013) Arch Biochem Biophys 530(2):73-82]. Herein, we present, to our knowledge, the first X-ray crystal structure for a full-length mammalian (rat) PAH in an autoinhibited conformation. Chromatographic isolation of a monodisperse tetrameric PAH, in the absence of Phe, facilitated determination of the 2.9 Å crystal structure. The structure of full-length PAH supersedes a composite homology model that had been used extensively to rationalize phenylketonuria genotype-phenotype relationships. Small-angle X-ray scattering (SAXS) confirms that this tetramer, which dominates in the absence of Phe, is different from a Phe-stabilized allosterically activated PAH tetramer. The lack of structural detail for activated PAH remains a barrier to complete understanding of phenylketonuria genotype-phenotype relationships. Nevertheless, the use of SAXS and X-ray crystallography together to inspect PAH structure provides, to our knowledge, the first complete view of the enzyme in a tetrameric form that was not possible with prior partial crystal structures, and facilitates interpretation of a wealth of biochemical and structural data that was hitherto impossible to evaluate.

  10. [Hemoglobins, XLVIII: the primary structure of hemoglobin of the Indian elephant (Elephas maximus, Proboscidea): beta 2 = Asn]. (United States)

    Braunitzer, G; Jelkmann, W; Stangl, A; Schrank, B; Krombach, C


    The primary structure of the hemoglobin of the Indian Elephant (Elephas maximus) is given. The sequence was determined automatically in a sequenator. By homologous comparison with adult human HbA, the alpha-chains differ by 24 exchanges and the beta-chains by 27 exchanges. Furthermore, we report p(O2)50 values with regard to altered contact sites with 2,3-bisphosphoglycerate in Indian elephant hemoglobin. Our findings explain the low p(O2)50 and the reduced interaction with 2,3-bisphosphoglycerate. Elephant hemoglobin has, like that of the Llama, only five phosphate binding sites. In addition, we have made an attempt to relate these results to aspects of respiratory physiology. Some implications of these biochemical and physiological results, concerning the Second Punic War and Hannibal's Alp transition, are given.

  11. Recent Advances in the Total Synthesis of Tetramic Acid-Containing Natural Products

    Directory of Open Access Journals (Sweden)

    Wen-Ju Bai


    Full Text Available With incredible bioactivities and fascinating structural complexities, tetramic acid- (TA- containing natural products have attracted favorable attention among the organic chemistry community. Although the construction of the TA core is usually straightforward, the intricate C3-side chain sometimes asks for some deliberative strategy so as to fulfill an elegant total synthesis. This review mainly covers some exceptional synthetic examples for each type of natural product in recent years, showcasing the great achievements as well as unsettled obstacles in this area, in the hope of accelerating the synthetic and biological investigations for this unique type of natural product.

  12. Mapping of hemoglobin in erythrocytes and erythrocyte ghosts using two photon excitation fluorescence microscopy (United States)

    Bukara, Katarina; Jovanić, Svetlana; Drvenica, Ivana T.; Stančić, Ana; Ilić, Vesna; Rabasović, Mihailo D.; Pantelić, Dejan; Jelenković, Branislav; Bugarski, Branko; Krmpot, Aleksandar J.


    The present study describes utilization of two photon excitation fluorescence (2PE) microscopy for visualization of the hemoglobin in human and porcine erythrocytes and their empty membranes (i.e., ghosts). High-quality, label- and fixation-free visualization of hemoglobin was achieved at excitation wavelength 730 nm by detecting visible autofluorescence. Localization in the suspension and spatial distribution (i.e., mapping) of residual hemoglobin in erythrocyte ghosts has been resolved by 2PE. Prior to the 2PE mapping, the presence of residual hemoglobin in the bulk suspension of erythrocyte ghosts was confirmed by cyanmethemoglobin assay. 2PE analysis revealed that the distribution of hemoglobin in intact erythrocytes follows the cells' shape. Two types of erythrocytes, human and porcine, characterized with discocyte and echinocyte morphology, respectively, showed significant differences in hemoglobin distribution. The 2PE images have revealed that despite an extensive washing out procedure after gradual hypotonic hemolysis, a certain amount of hemoglobin localized on the intracellular side always remains bound to the membrane and cannot be eliminated. The obtained results open the possibility to use 2PE microscopy to examine hemoglobin distribution in erythrocytes and estimate the purity level of erythrocyte ghosts in biotechnological processes.

  13. Hemoglobin (United States)

    ... Failure of the right side of the heart ( cor pulmonale ) Severe chronic obstructive pulmonary disease (COPD) Scarring or ... chronic disease Aplastic anemia Bleeding CBC blood test Cor pulmonale Diabetes Drug-induced immune hemolytic anemia Erythropoietin test ...

  14. Hemoglobin (United States)

    Advertisement Proceeds from website advertising help sustain Lab Tests Online. AACC is a not-for-profit organization and does not endorse non-AACC products and services. Advertising & Sponsorship: Policy | Opportunities ...

  15. Molecular structure of hydrazoic acid with hydrogen-bonded tetramers in nearly planar layers. (United States)

    Evers, Jürgen; Göbel, Michael; Krumm, Burkhard; Martin, Franz; Medvedyev, Sergey; Oehlinger, Gilbert; Steemann, Franz Xaver; Troyan, Ivan; Klapötke, Thomas M; Eremets, Mikhail I


    Hydrazoic acid (HN(3))--potentially explosive, highly toxic, and very hygroscopic--is the simplest covalent azide and contains 97.7 wt % nitrogen. Although its molecular structure was established decades ago, its crystal structure has now been solved by X-ray diffraction for the first time. Molecules of HN(3) are connected to each other by hydrogen bonds in nearly planar layers parallel to (001) with stacking sequence A, B, ... The layer distance, at 2.950(1) Å, is shorter than that in 2H-graphite [3.355(2) Å]. The hydrogen bonds N-H···N are of great interest, since the azido group consists of three homonuclear atoms with identical electronegativity, but different formal charges. These hydrogen bonds are bifurcated into moderate ones with ≈2.0 Å and into weak ones with ≈2.6 Å. The moderate ones build up tetramers (HN(3))(4) in a nearly planar net of eight-membered rings. To the best of our knowledge, such a network of tetramers of a simple molecule is unique.

  16. Creation and Evaluation of a Single-chain Antibody Tetramer that Targets Brain Endothelial Cells. (United States)

    Zhang, Xiaobin; Wang, Xin Xiang; Shusta, Eric V


    Antibodies that target and internalize into blood-brain barrier (BBB) endothelial cells offer promise as drug delivery agents. Previously, we identified a single-chain antibody (scFvA) capable of binding to the BBB. In an attempt to improve the binding and internalization properties of the single chain antibody (scFvA), a biotinylation tag (Avitag) was fused to scFvA and the protein secreted by yeast. The scFvA-Avitag could be biotinylated by yeast-displayed BirA enzyme and biotinylated scFvA-Avitag could be used to create scFv tetramers. Tetramerization of scFvA improved the internalization of scFvA into BBB endothelial cells, and biotinylated scFvA-Avitag could also be used to target streptavidin-coated quantum dots for BBB endothelial cell internalization. Perfusing the rat brain with scFvA-tetramer confirmed that the antigen targeted by scFvA is distributed on blood side of the BBB, suggesting the potential for downstream application of scFvA in brain-targeted drug delivery.

  17. Influence of hemoglobin on non-invasive optical bilirubin sensing (United States)

    Jiang, Jingying; Gong, Qiliang; Zou, Da; Xu, Kexin


    Since the abnormal metabolism of bilirubin could lead to diseases in the human body, especially the jaundice which is harmful to neonates. Traditional invasive measurements are difficult to be accepted by people because of pain and infection. Therefore, the real-time and non-invasive measurement of bilirubin is of great significance. However, the accuracy of currently transcutaneous bilirubinometry(TcB) is generally not high enough, and affected by many factors in the human skin, mostly by hemoglobin. In this talk, absorption spectra of hemoglobin and bilirubin have been collected and analyzed, then the Partial Least Squares (PLS) models have been built. By analyzing and comparing the Correlation and Root Mean Square Error of Prediction(RMSEP), the results show that the Correlation of bilirubin solution model is larger than that of the mixture solution added with hemoglobin, and its RMSEP value is smaller than that of mixture solution. Therefore, hemoglobin has influences on the non-invasive optical bilirubin sensing. In next step, it is necessary to investigate how to eliminate the influence.

  18. Hemoglobin variant (hemoglobin Aalborg) mimicking interstitial pulmonary disease. (United States)

    Panou, Vasiliki; Jensen, Peter-Diedrich Mathias; Pedersen, Jan Freddy; Thomsen, Lars Pilegaard; Weinreich, Ulla Møller


    Hemoglobin Aalborg is a moderately unstable hemoglobin variant with no affiliation to serious hematological abnormality or major clinical symptoms under normal circumstances. Our index person was a healthy woman of 58, not previously diagnosed with hemoglobinopathy Aalborg, who developed acute respiratory failure after a routine cholecystectomy. Initially she was suspected of idiopathic interstitial lung disease, yet a series of tests uncovered various abnormal physiological parameters and set the diagnosis of hemoglobinopathy Aalborg. This led us to examine a group of the index person's relatives known with hemoglobinopathy Aalborg in order to study whether the same physiological abnormalities would be reencountered. They were all subjected to spirometry and body plethysmography, six-minute walking test, pulse oximetry, and arterial blood gas samples before and after the walking test. The entire study population presented the same physiological anomalies: reduction in diffusion capacity, and abnormalities in P(a)O2 and p50 values; the latter could not be presented by the arterial blood gas analyzer; furthermore there was concordance between pulse oximetry and arterial blood gas samples regarding saturation. These data suggest that, based upon the above mentioned anomalies in physiological parameters, the diagnosis of hemoglobinopathy Aalborg should be considered.

  19. Hemoglobin Variant (Hemoglobin Aalborg Mimicking Interstitial Pulmonary Disease

    Directory of Open Access Journals (Sweden)

    Vasiliki Panou


    Full Text Available Hemoglobin Aalborg is a moderately unstable hemoglobin variant with no affiliation to serious hematological abnormality or major clinical symptoms under normal circumstances. Our index person was a healthy woman of 58, not previously diagnosed with hemoglobinopathy Aalborg, who developed acute respiratory failure after a routine cholecystectomy. Initially she was suspected of idiopathic interstitial lung disease, yet a series of tests uncovered various abnormal physiological parameters and set the diagnosis of hemoglobinopathy Aalborg. This led us to examine a group of the index person’s relatives known with hemoglobinopathy Aalborg in order to study whether the same physiological abnormalities would be reencountered. They were all subjected to spirometry and body plethysmography, six-minute walking test, pulse oximetry, and arterial blood gas samples before and after the walking test. The entire study population presented the same physiological anomalies: reduction in diffusion capacity, and abnormalities in PaO2 and p50 values; the latter could not be presented by the arterial blood gas analyzer; furthermore there was concordance between pulse oximetry and arterial blood gas samples regarding saturation. These data suggest that, based upon the above mentioned anomalies in physiological parameters, the diagnosis of hemoglobinopathy Aalborg should be considered.

  20. Hemoglobin Labeled by Radioactive Lysine (United States)

    Bale, W. F.; Yuile, C. L.; DeLaVergne, L.; Miller, L. L.; Whipple, G. H.


    This paper reports on the utilization of tagged epsilon carbon of DL-lysine by a dog both anemic and hypoproteinemic due to repeated bleeding plus a diet low in protein. The experiment extended over period of 234 days, a time sufficient to indicate an erythrocyte life span of at least 115 days based upon the rate of replacement of labeled red cell proteins. The proteins of broken down red cells seem not to be used with any great preference for the synthesis of new hemoglobin.

  1. 双抗体夹心ELISA检测人胎儿血红蛋白体系的建立%Establishment of a sandwich-ELISA system for determination of human fetal hemoglobin

    Institute of Scientific and Technical Information of China (English)

    李雪丽; 文李艳; 冯善伟; 钟梅; 刘艳君; 富宁


    目的 建立一种定量检测人胎儿血红蛋白(HbF)的双抗体夹心ELISA方法.方法 用抗人HbF单抗作为捕获抗体,加入待测抗原,检测抗体为兔抗人HbF多克隆抗体,最后加入辣根过氧化物酶标记的羊抗兔IgG.结果 本检测体系灵敏度约为0.039 μg/ml,测量范围0.039-24.66 μg/ml,特异性强,重复性好,100份血标本的检测结果与高效液相色谱法结果符合率高.结论 建立了一种可用于检测人外周血HbF的双抗体夹心ELISA方法,有望为临床上诊断某些与HbF有关的疾病提供帮助.%Objective To establish a sandwich ELISA for the determination of fetal hemoglobin (HbF) in human blood. Methods An anti HbF monoclonal antibody was coated on polystyrene microtiter plates followed by blocking with 5% defat milkithen samples for detection were added to the wells,followed by anti HbF polyclonal antibody pre pared, from rabbit; at last 、addition of HRP goat anti rabbit IgG and. Conventional color development were performed. Re suits This sandwich ELISA system can determine HbF specifically,the sensitivity for HbF is 0. 039 μg/ml,the range of detection is 0. 039 - 24. 66 μg/ml. Conclusion This HbF ELISA is applicable for research and observation in clini cal.

  2. The PRE-Derived NMR Model of the 38.8-kDa Tri-Domain IsdH Protein from Staphylococcus aureus Suggests That It Adaptively Recognizes Human Hemoglobin. (United States)

    Sjodt, Megan; Macdonald, Ramsay; Spirig, Thomas; Chan, Albert H; Dickson, Claire F; Fabian, Marian; Olson, John S; Gell, David A; Clubb, Robert T


    Staphylococcus aureus is a medically important bacterial pathogen that, during infections, acquires iron from human hemoglobin (Hb). It uses two closely related iron-regulated surface determinant (Isd) proteins to capture and extract the oxidized form of heme (hemin) from Hb, IsdH and IsdB. Both receptors rapidly extract hemin using a conserved tri-domain unit consisting of two NEAT (near iron transporter) domains connected by a helical linker domain. To gain insight into the mechanism of extraction, we used NMR to investigate the structure and dynamics of the 38.8-kDa tri-domain IsdH protein (IsdH(N2N3), A326-D660 with a Y642A mutation that prevents hemin binding). The structure was modeled using long-range paramagnetic relaxation enhancement (PRE) distance restraints, dihedral angle, small-angle X-ray scattering, residual dipolar coupling and inter-domain NOE nuclear Overhauser effect data. The receptor adopts an extended conformation wherein the linker and N3 domains pack against each other via a hydrophobic interface. In contrast, the N2 domain contacts the linker domain via a hydrophilic interface and, based on NMR relaxation data, undergoes inter-domain motions enabling it to reorient with respect to the body of the protein. Ensemble calculations were used to estimate the range of N2 domain positions compatible with the PRE data. A comparison of the Hb-free and Hb-bound forms reveals that Hb binding alters the positioning of the N2 domain. We propose that binding occurs through a combination of conformational selection and induced-fit mechanisms that may promote hemin release from Hb by altering the position of its F helix.

  3. Mass Spectra and Ion Collision Cross Sections of Hemoglobin (United States)

    Kang, Yang; Terrier, Peran; Douglas, D. J.


    Mass spectra of commercially obtained hemoglobin (Hb) show higher levels of monomer and dimer ions, heme-deficient dimer ions, and apo-monomer ions than hemoglobin freshly prepared from blood. This has previously been attributed to oxidation of commercial Hb. Further, it has been reported that that dimer ions from commercial bovine Hb have lower collision cross sections than low charge state monomer ions. To investigate these effects further, we have recorded mass spectra of fresh human Hb, commercial human and bovine Hb, fresh human Hb oxidized with H2O2, lyophilized fresh human Hb, fresh human Hb both lyophilized and chemically oxidized, and commercial human Hb oxidized with H2O2. Masses of α-monomer ions of all hemoglobins agree with the masses expected from the sequences within 3 Da or better. Mass spectra of the β chains of commercial Hb and oxidized fresh human Hb show a peak or shoulder on the high mass side, consistent with oxidation of the protein. Both commercial proteins and oxidized fresh human Hb produce heme-deficient dimers with masses 32 Da greater than expected and higher levels of monomer and dimer ions than fresh Hb. Lyophilization or oxidation of Hb both produce higher levels of monomer and dimer ions in mass spectra. Fresh human Hb, commercial human Hb, commercial bovine Hb, and oxidized commercial human Hb all give dimer ions with cross sections greater than monomer ions. Thus, neither oxidation of Hb or the difference in sequence between human and bovine Hb make substantial differences to cross sections of ions.


    Directory of Open Access Journals (Sweden)

    Amit Kumar


    Full Text Available Bright red hemoglobins, the most well-known paradigm in protein science, seem to be ubiquitous in nature. With advances in modern tools and techniques, discovery of new globins at a rapid pace has expanded this family. With every discovery, new insights emerged regarding their novel structure, function and several other characteristics previously not observed for hemoglobins. Even the classical function unanimously assigned to hemoglobins – oxygen transport and storage – needed re-evaluation. The ability of this class of proteins to show responses against various gaseous ligands, even the poisonous ones, indicate that it is obviously as ancient as life. As organisms evolved, hemoglobins also evolved, and accumulated a great degree of diversity in all aspects. The classical globin fold is very unique with 3-on-3 alpha helical bundle as observed in the traditional oxygen-transport hemoglobins like myoglobin, human blood hemoglobin and leghemoglobins in plants. However, a class of the newly discovered hemoglobins, which dominate the superfamily and appears ancient in origin mostly have 2-on-2 fold, commonly termed as “truncated” hemoglobins. These hemoglobins are phylogenetically distinct from their classical counterparts and are often shorter in their polypeptide length by 20-40 residues mainly due to a lack of short A helix, D helix and F helix. However, hemoglobins with 2-on-2 fold were also later found to have polypeptide chain lengths similar in size to classical globins. Disordered pre-F helix region, conserved glycine motifs and other key residues and apolar tunnels through their protein matrix for migration of ligands are some unique characteristics features of these truncated hemoglobins. Some of these are also hexacoordinated at heme iron where an amino acid from within the protein coordinates heme iron in absence of a ligand. These hemoglobins are well known for their high affinity towards ligand and have a diverse mechanism of

  5. Hemoglobin-Spectrin Complexes: Interference with Spectrin Tetramer Assembly as a Mechanism for Compartmentalization of Band 1 and Band 2 Complexes (United States)


    Kiefer CR, Shyamala M, Moscoso H, Garver FA: Negative screening for sickle cell diseases with a monoclonal immunoassay on newborn blood eiuted from...spectrin, 1 mg/ml; B, 6//M Hb + spectrin; C, spectrin + 147„M H202; D, Hb + spectrin + 147 //M H202; E, spectrin + 489 //M H202; F, Hb + spectrin...489 //M H202; G, Hb (pretreated with CO) + spectrin + 489 „M H20 Ten microliters was loaded per gel. 2^2 • Fig 2. Split-lane Western blot

  6. Effect of glycation of hemoglobin on its interaction with trifluoperazine. (United States)

    Kar, Manoj; Roy, Anjana; Bose, Tania; Chakraborti, Abhay Sankar


    Trifluoperazine (TFZ), a phenothiazine drug, penetrates into human erythrocytes and releases oxygen by interaction with hemoglobin. TFZ-induced oxygen release from hyperglycemic erythrocytes isolated from diabetic patients is considerably less compared to that from the cells of normoglycemic individuals. In diabetes mellitus, hemoglobin is significantly glycated by glucose. Non-glycated hemoglobin, HbA0 and its major glycated analog, HbA1c have been separated from the blood samples of diabetic patients. TFZ releases considerable amount of oxygen from HbA0, but very little from HbA1c. Spectrofluorimetric studies reveal that TFZ forms excited state complexes with both HbA0 and HbAlc. Titration of HbA0 with TFZ in a spectrophotometric study exhibits two isosbestic points. Similar experiment with HbAlc causes gradual loss of the Soret peak without appearance of any isosbestic point indicating a possibility of heme loss during interaction, which is also supported by gel filtration experiment and SDS-PAGE experiment followed by heme staining. The results suggest that drug action on hemoglobin is influenced by glycation-induced structural modification of the protein.

  7. Photoinduced reversible switching of porosity in molecular crystals based on star-shaped azobenzene tetramers. (United States)

    Baroncini, Massimo; d'Agostino, Simone; Bergamini, Giacomo; Ceroni, Paola; Comotti, Angiolina; Sozzani, Piero; Bassanetti, Irene; Grepioni, Fabrizia; Hernandez, Taylor M; Silvi, Serena; Venturi, Margherita; Credi, Alberto


    The development of solid materials that can be reversibly interconverted by light between forms with different physico-chemical properties is of great interest for separation, catalysis, optoelectronics, holography, mechanical actuation and solar energy conversion. Here, we describe a series of shape-persistent azobenzene tetramers that form porous molecular crystals in their E-configuration, the porosity of which can be tuned by changing the peripheral substituents on the molecule. Efficient E→Z photoisomerization of the azobenzene units takes place in the solid state and converts the crystals into a non-porous amorphous melt phase. Crystallinity and porosity are restored upon Z→E isomerization promoted by visible light irradiation or heating. We demonstrate that the photoisomerization enables reversible on/off switching of optical properties such as birefringence as well as the capture of CO2 from the gas phase. The linear design, structural versatility and synthetic accessibility make this new family of materials potentially interesting for technological applications.

  8. Lac repressor: Crystallization of intact tetramer and its complexes with inducer and operator DNA

    Energy Technology Data Exchange (ETDEWEB)

    Pace, H.C.; Lu, P. (Univ. of Pennsylvania, Philadelphia (USA)); Lewis, M. (Univ. of Pennsylvania, Philadelphia, (USA) Smith Kline and French Labs., King of Prussia, PA (USA))


    The intact lac repressor tetramer, which regulates expression of the lac operon in Escherichia coli, has been crystallized in the native form, with an inducer, and in a ternary complex with operator DNA and an anti-inducer. The crystals without DNA diffract to better than 3.5 {angstrom}. They belong to the monoclinic space group C2 and have cell dimensions a = 164.7 {angstrom}, b = 75.6 {angstrom}, and c = 161.2 {angstrom}, with {alpha} = {gamma} = 90{degree} and {beta} = 125.5{degree}. Cocrystals have been obtained with a number of different lac operator-related DNA fragments. The complex with a blunt-ended 16-base-pair strand yielded tetragonal bipyramids that diffract to 6.5 {angstrom}. These protein-DNA cocrystals crack upon exposure to the gratuitous inducer isopropyl {beta}-D-thiogalactoside, suggesting a conformational change in the repressor-operator complex.

  9. Characterization of Aniline Tetramer by MALDI TOF Mass Spectrometry upon Oxidative and Reductive Cycling

    Directory of Open Access Journals (Sweden)

    Rebecca L. Li


    Full Text Available By combining electrochemical experiments with mass spectrometric analysis, it is found that using short chain oligomers to improve the cycling stability of conducting polymers in supercapacitors is still problematic. Cycling tests via cyclic voltammetry over a potential window of 0 to 1.0 V or 0 to 1.2 V in a two-electrode device configuration resulted in solid-state electropolymerization and chain scission. Electropolymerization of the aniline tetramer to generate long chain oligomers is shown to be possible despite the suggested decrease in reactivity and increase in intermediate stability with longer oligomers. Because aniline oligomers are more stable towards reductive cycling when compared to oxidative cycling, future conducting polymer/oligomer-based pseudocapacitors should consider using an asymmetric electrode configuration.

  10. Reactivity of a Pt(100) cluster modified by adsorption of a nickel tetramer

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, E V; Lopez, M B [Centro de Investigaciones Fisicoquimicas, Teoricas y Aplicadas (CIFTA), Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Catamarca, Av. Belgrano 300, (4700), Catamarca (Argentina); Castro, E A, E-mail: [INIFTA, CONICET, Universidad Nacional de la Plata, Diag. 113 y 64, Suc.4, C.C. 16, (1900), La Plata (Argentina)


    The aim of this paper is to report a study of the reactivity of Pt(100) cluster and the same system modified by a nickel tetramer towards the atomic hydrogen adsorption. This study was carried out in the framework of density functional theory which provides global and local indexes that can be used to characterize the reactivity. The analyzed reactivity descriptors were: chemical potential, chemical hardness, electrophilicity index and Fukui function. The results showed that the global reactivity descriptor predicts that the platinum cluster modified by nickel is more reactive than the pure platinum cluster and that the local Fukui function provides information about the most susceptible site to electrophilic attack in platinum cluster.

  11. Synthesis, Characterization, and Antifungal Activity of Phenylpyrrole-Substituted Tetramic Acids Bearing Carbonates

    Directory of Open Access Journals (Sweden)

    Wen-Qin Xu


    Full Text Available For the aim of discovering new fungicide, a series of phenylpyrrole-substituted tetramic acid derivatives bearing carbonates 6a–q were designed and synthesized via 4-(2,4-dioxopyrrolidin-3-ylidene-4-(phenylaminobutanoic acids 4a–k and the cyclized products 1′,3,4,5′-tetrahydro-[2,3′-bipyrrolylidene]-2′,4′,5(1H-triones 5a–k. The compounds were characterized using IR, 1H- and 13C-NMR spectroscopy, mass spectrometry (EI-MS, and elemental analysis. The structure of 6b was confirmed by X-ray diffraction crystallography. The title compounds 6a–q were bioassayed in vitro against the phytopathogenic fungi Fusarium graminearum, Botrytis cinerea and Rhizoctonia solani at a concentration of 100 μg/mL, respectively. Most compounds displayed good inhibitory activity.

  12. Channel catfish hemoglobin genes: identification, phylogenetic and syntenic analysis, and specific induction in response to heat stress. (United States)

    Feng, Jianbin; Liu, Shikai; Wang, Xiuli; Wang, Ruijia; Zhang, Jiaren; Jiang, Yanliang; Li, Chao; Kaltenboeck, Ludmilla; Li, Jiale; Liu, Zhanjiang


    Hemoglobins transport oxygen from gill to inner organs in fish, and this process is affected by temperature, one of the major environmental factors for fish. The hemoglobin gene clusters have been well studied in humans and several model fish species, but remain largely unknown in catfish. Here, eight α- and six β-hemoglobin genes were identified and characterized in channel catfish. Genomic synteny analysis showed that these hemoglobin genes were separated into two unlinked clusters, the MN cluster containing six α- and six β-hemoglobin genes, and the LA cluster consisting of two α-hemoglobin genes. Channel catfish hemoglobin genes were ubiquitously expressed in all the 10 tested tissues from healthy fish, but exhibited higher expression level in spleen, head kidney, and trunk kidney. In response to heat stress, hemoglobin genes, especially MN Hbα4, MN Hbα5, MN Hbα6, MN Hbβ4, MN Hbβ5, MN Hbβ6, LA Hbα1, and LA Hbα2, presumably the embryonic hemoglobin genes, were drastically up-regulated in the gill and head kidney of heat-tolerant fishes, but not in these tissues of the heat-intolerant fish, suggesting the importance of the embryonic hemoglobin genes in coping with the low oxygen conditions under heat stress.

  13. Vaticanol C, a resveratrol tetramer, activates PPARα and PPARβ/δ in vitro and in vivo

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    Akao Yukihiro


    Full Text Available Abstract Background Appropriate long-term drinking of red wine is associated with a reduced risk of cardiovascular disease. Resveratrol, a well-known SIRT1 activator is considered to be one of the beneficial components contained in red wine, and also developed as a drug candidate. We previously demonstrated that resveratrol protects brain against ischemic stroke in mice through a PPARα-dependent mechanism. Here we report the different effects of the oligomers of resveratrol. Methods We evaluated the activation of PPARs by ε-viniferin, a resveratrol dimer, and vaticanol C, a resveratrol tetramer, in cell-based reporter assays using bovine arterial endothelial cells, as well as the activation of SIRT1. Moreover, we tested the metabolic action by administering vaticanol C with the high fat diet to wild-type and PPARα-knockout male mice for eight weeks. Results We show that vaticanol C activates PPARα and PPARβ/δ in cell-based reporter assays, but does not activate SIRT1. ε-Viniferin shows a similar radical scavenging activity as resveratrol, but neither effects on PPARs and SIRT-1. Eight-week intake of vaticanol C with a high fat diet upregulates hepatic expression of PPARα-responsive genes such as cyp4a10, cyp4a14 and FABP1, and skeletal muscle expression of PPARβ/δ-responsive genes, such as UCP3 and PDK4 (pyruvate dehydrogenase kinase, isoform 4, in wild-type, but not PPARα-knockout mice. Conclusion Vaticanol C, a resveratrol tetramer, activated PPARα and PPARβ/δ in vitro and in vivo. These findings indicate that activation of PPARα and PPARβ/δ by vaticanol C may be a novel mechanism, affording beneficial effects against lifestyle-related diseases.


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    Benjamin C. Stark


    Full Text Available The hemoglobin (VHb from Vitreoscilla was the first bacterial hemoglobin discovered. Its structure and function have been extensively investigated, and engineering of a wide variety of heterologous organisms to express VHb has been performed to increase their growth and productivity. This strategy has shown promise in applications as far-ranging as the production of antibiotics and petrochemical replacements by microorganisms to increasing stress tolerance in plants. These applications of “VHb technology” have generally been of the “black box” variety, wherein the endpoint studied is an increase in the levels of a certain product or improved growth and survival. Their eventual optimization, however, will require a thorough understanding of the various functions and activities of VHb, and how VHb expression ripples to affect metabolism more generally. Here we review the current knowledge of these topics. VHb's functions all involve oxygen binding (and often delivery in one way or another. Several biochemical and structure-function studies have provided an insight into the molecular details of this binding and delivery. VHb activities are varied. They include supply of oxygen to oxygenases and the respiratory chain, particularly under low oxygen conditions; oxygen sensing and modulation of transcription factor activity; and detoxification of NO, and seem to require interactions of VHb with “partner proteins”. VHb expression affects the levels of ATP and NADH, although not enormously. VHb expression may affect the level of many compounds of intermediary metabolism, and, apparently, alters the levels of expression of many genes. Thus, the metabolic changes in organisms engineered to express VHb are likely to be numerous and complicated.

  15. Led Astray by Hemoglobin A1c

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    Jean Chen MD


    Full Text Available Hemoglobin A1c (A1c is used frequently to diagnose and treat diabetes mellitus. Therefore, it is important be aware of factors that may interfere with the accuracy of A1c measurements. This is a case of a rare hemoglobin variant that falsely elevated a nondiabetic patient’s A1c level and led to a misdiagnosis of diabetes. A 67-year-old male presented to endocrine clinic for further management after he was diagnosed with diabetes based on an elevated A1c of 10.7%, which is approximately equivalent to an average blood glucose of 260 mg/dL. Multiple repeat A1c levels remained >10%, but his home fasting and random glucose monitoring ranged from 92 to 130 mg/dL. Hemoglobin electrophoresis and subsequent genetic analysis diagnosed the patient with hemoglobin Wayne, a rare hemoglobin variant. This variant falsely elevates A1c levels when A1c is measured using cation-exchange high-performance liquid chromatography. When the boronate affinity method was applied instead, the patient’s A1c level was actually 4.7%. Though hemoglobin Wayne is clinically silent, this patient was erroneously diagnosed with diabetes and started on an antiglycemic medication. Due to this misdiagnosis, the patient was at risk of escalation in his “diabetes management” and hypoglycemia. Therefore, it is important that providers are aware of factors that may result in hemoglobin A1c inaccuracy including hemoglobin variants.

  16. Using stable MutS dimers and tetramers to quantitatively analyze DNA mismatch recognition and sliding clamp formation

    NARCIS (Netherlands)

    M.K. Groothuizen; A. Fish (Alexander); M.V. Petoukhov (Maxim); A. Reumer (Annet); L. Manelyte (Laura); H.H.K. Winterwerp (Herrie); M.G. Marinus (Martin); J.H.G. Lebbink (Joyce); D.I. Svergun (Dmitri); P. Friedhoff (Peter); T.K. Sixma (Titia)


    textabstractThe process of DNA mismatch repair is initiated when MutS recognizes mismatched DNA bases and starts the repair cascade. The Escherichia coli MutS protein exists in an equilibrium between dimers and tetramers, which has compromised biophysical analysis. To uncouple these states, we have

  17. Tetramer guided, cell sorter assisted production of clinical grade autologous NY-ESO-1 specific CD8(+) T cells. (United States)

    Pollack, Seth M; Jones, Robin L; Farrar, Erik A; Lai, Ivy P; Lee, Sylvia M; Cao, Jianhong; Pillarisetty, Venu G; Hoch, Benjamin L; Gullett, Ashley; Bleakley, Marie; Conrad, Ernest U; Eary, Janet F; Shibuya, Kendall C; Warren, Edus H; Carstens, Jason N; Heimfeld, Shelly; Riddell, Stanley R; Yee, Cassian


    Adoptive T cell therapy represents an attractive modality for the treatment of patients with cancer. Peripheral blood mononuclear cells have been used as a source of antigen specific T cells but the very low frequency of T cells recognizing commonly expressed antigens such as NY-ESO-1 limit the applicability of this approach to other solid tumors. To overcome this, we tested a strategy combining IL-21 modulation during in vitro stimulation with first-in-class use of tetramer-guided cell sorting to generate NY-ESO-1 specific cytotoxic T lymphocytes (CTL). CTL generation was evaluated in 6 patients with NY-ESO-1 positive sarcomas, under clinical manufacturing conditions and characterized for phenotypic and functional properties. Following in vitro stimulation, T cells stained with NY-ESO-1 tetramer were enriched from frequencies as low as 0.4% to >90% after single pass through a clinical grade sorter. NY-ESO-1 specific T cells were generated from all 6 patients. The final products expanded on average 1200-fold to a total of 36 billion cells, were oligoclonal and contained 67-97% CD8(+), tetramer(+) T cells with a memory phenotype that recognized endogenous NY-ESO-1. This study represents the first series using tetramer-guided cell sorting to generate T cells for adoptive therapy. This approach, when used to target more broadly expressed tumor antigens such as WT-1 and additional Cancer-Testis antigens will enhance the scope and feasibility of adoptive T cell therapy.

  18. Relative phase of oscillations of cerebral oxy-hemoglobin and deoxy-hemoglobin concentrations during sleep (United States)

    Pierro, Michele L.; Sassaroli, Angelo; Bergethon, Peter R.; Fantini, Sergio


    We present a near-infrared spectroscopy study of the instantaneous phase difference between spontaneous oscillations of cerebral deoxy-hemoglobin and oxy-hemoglobin concentrations ([Hb] and [HbO], respectively) in the low-frequency range, namely 0.04-0.12 Hz. We report phase measurements during the transitions between different sleep stages in a whole-night study of a human subject. We have found that the phase difference between [Hb] and [HbO] low-frequency oscillations tends to be greater in deep sleep (by ~96° on average) and REM sleep (by ~77° on average) compared to the awake state. In particular, we have observed progressive phase increases as the subject transitions from awake conditions into non-REM sleep stages N1, N2, and N3. Corresponding phase decreases were recorded in the reversed transitions from sleep stages N3 to N2, and N2 to awake. These results illustrate the physiological information content of phase measurements of [Hb] and [HbO] oscillations that reflect the different cerebral hemodynamic conditions of the different sleep stages, and that can find broader applicability in a wide range of near-infrared spectroscopy brain studies.

  19. Effects of crosslinking on the thermal stability of hemoglobin. I. The use of bis(3,5-dibromosalicyl) fumarate. (United States)

    White, F L; Olsen, K W


    The double-headed aspirin, bis(3,5-dibromosalicyl) fumarate, has been used to crosslink hemoglobin A between Lys 82 beta 1 and Lys 82 beta 2 (J. A. Walder et al. (1979) Biochemistry 18,4265). Denaturation experiments were used to compare the stability of this crosslinked protein to that of hemoglobin A. Thermal denaturations, done in 0.01 M 4-morpholine-propanesulfonic acid, pH 7, containing 0.9 M guanidine to prevent precipitation at high temperatures, were monitored by changes in absorbance between 190 and 650 nm using a diode array spectrophotometer. The sample was heated from 25 to 70 degrees C at 0.3 degrees C/min. The data were analyzed by using both a two-state model and a novel first derivative method. As expected, methemoglobin A had a single, broad transition with a midpoint of 40.7 degrees C. The crosslinked methemoglobin showed a transition at 57.1 degrees C. Two minor transitions, one of which was apparently due to residual unmodified hemoglobin, were also observed in the crosslinked sample. Thus, a single crosslink between only two of the four subunits can lead to a significantly more stable molecule. These results can be explained by Le Chatelier's principle, since crosslinking prevents dissociation of the beta-subunits and, thereby, holds the entire tetramer together.


    Lilly, Laura E.; Blinebry, Sara K.; Viscardi, Chelsea M.; Perez, Luis; Bonaventura, Joe; McMahon, Tim J.


    Methods to systematically analyze in parallel the function of multiple protein or cell samples in vivo or ex vivo (i.e. functional proteomics) in a controlled gaseous environment have thus far been limited. Here we describe an apparatus and procedure that enables, for the first time, parallel assay of oxygen equilibria in multiple samples. Using this apparatus, numerous simultaneous oxygen equilibrium curves (OECs) can be obtained under truly identical conditions from blood cell samples or purified hemoglobins (Hbs). We suggest that the ability to obtain these parallel datasets under identical conditions can be of immense value, both to biomedical researchers and clinicians who wish to monitor blood health, and to physiologists studying non-human organisms and the effects of climate change on these organisms. Parallel monitoring techniques are essential in order to better understand the functions of critical cellular proteins. The procedure can be applied to human studies, wherein an OEC can be analyzed in light of an individual’s entire genome. Here, we analyzed intraerythrocytic Hb, a protein that operates at the organism’s environmental interface and then comes into close contact with virtually all of the organism’s cells. The apparatus is theoretically scalable, and establishes a functional proteomic screen that can be correlated with genomic information on the same individuals. This new method is expected to accelerate our general understanding of protein function, an increasingly challenging objective as advances in proteomic and genomic throughput outpace the ability to study proteins’ functional properties. PMID:23827235

  1. Entamoeba histolytica HM1:IMSS: hemoglobin-degrading neutral cysteine proteases. (United States)

    Serrano-Luna, J J; Negrete, E; Reyes, M; de la Garza, M


    Entamoeba histolytica HMI:IMSS trophozoites were able to utilize human hemoglobin but not hemin as a sole iron source to grow in vitro. Proteases from crude extracts of E. histolytica degraded human, porcine, and bovine hemoglobins at pH 7.0. These proteolytic activities were found by electrophoresis in SDS-polyacrylamide gels copolymerized with hemoglobin, with apparent molecular weights of 116, 82, and 21 kDa, the 82-kDa protein being the most active protease against this substrate. The proteases were classified in the cysteine group since the activities were inhibited by l-trans-epoxysuccinylleucylamido(4-guanidino)butane, p-hydroxymercuribenzoate, iodoacetate, and N-ethylmaleimide and activated with dithiothreitol. Other pathogenic strains of E. histolytica showed the same pattern of hemoglobinases. These hemoglobin-degrading proteases could be playing an important role in iron acquisition by E. histolytica.

  2. Nadir Hemoglobin Levels after Discontinuation of Epoetin in Hemodialysis Patients


    Calvo, Jose A.; Miskulin, Dana C.; Meyer, Klemens B.; Weiner, Daniel E.


    Background and objectives: In hemodialysis patients, both hemoglobin variability and targeting normalization of hemoglobin may have adverse consequences. There are few data on epoetin management in patients achieving high hemoglobin levels.

  3. Disuccinimidyl suberate cross-linked hemoglobin as a novel red blood cell substitute

    Institute of Scientific and Technical Information of China (English)

    LU; Xiuling; ZHENG; Chunyang; XU; Yuhong; SU; Zhiguo


    Disuccinimidyl suberate (DSS) intramolecularly cross-linked hemoglobin (Hb) was developed as a novel red blood cell substitute. A multi-angle laser light scattering detector coupled with size exclusion HPLC was applied to determine the molecular weight of the modified Hb. SDS-PAGE was also used as a complement. It was proved that 83.8% of the product was intramolecularly cross-linked Hb with weight-average molecular weights (Mw) of 67.5 kD, 12% was dimeric Hb with Mw of 146.6 kD, and 4.2% was trimeric Hb with Mw of 306.4 kD. The tetramer structure of the cross-linked Hb was stable as shown in size-exclusion chromatography using a mobile phase containing 1 mol/L MgCl2. Analysis by LC-MS demonstrated that the reaction of DSS with Hb mainly took place between the twoα subunits within a Hb molecule, resulting in stabilization of the tetramer structure. However, the cross-linking was not site-specific. The P50 of the cross-linked Hb decreased from 21.8 mmHg to 14.3 mmHg, and the Hill coefficient decreased from 2.22 to 1.41. Result of isoelectric focusing showed that the pI of DSS cross-linked Hb was in the range of 4.6-5.2, similar to that of serum albumin. The safety of DSS cross-linked Hb was favored by animal tests on rats and guinea pigs. Exchange transfusion experiment with DSS cross-linked Hb using rats as a model indicated no pressor effect or other significant side effects. The characteristics and properties of DSS cross-linked Hb were also compared with that of diaspirin cross-linked Hb reported in the literature.

  4. Diferencias entre la hemoglobina observada y estimada por hematocrito y su importancia en el diagnóstico de anemia en población costera venezolana: análisis del segundo estudio nacional de crecimiento y desarrollo humano (SENACREDH Differences between observed and estimated by hematocrit hemoglobin and its relevance in the diagnosis of anemia among coastal population in Venezuela: analysis of the second national study of human growth and development (SENACREDH

    Directory of Open Access Journals (Sweden)

    Jessica Flores-Torres


    Full Text Available Objetivos. Evaluar las diferencias entre el valor de hemoglobina observada y el valor estimado a partir del hematocrito en el marco del Segundo Estudio Nacional de Crecimiento y Desarrollo Humano de la Población Venezolana (SENACREDH en el eje centro norte costero del país. Materiales y métodos. Por medio de un muestreo probabilístico multietápico por conglomerados se seleccionó un total de 6004 sujetos que representan 7 286 781 habitantes del eje Centro Norte Costero (Vargas, Carabobo, Distrito Capital, Aragua y Miranda. Se compararon medias de la hemoglobina observada y hemoglobina estimada (hematocrito/3, usando la prueba t para muestras relacionadas. Se realizaron regresiones lineales entre hemoglobina observada y hematocrito. Resultados. Se observó que el promedio de las diferencias entre la asignadas a la hemoglobina observada y la estimada por el hematocrito fue de -0,3446 ± 0,0002 (pObjectives. To evaluate the differences between the observed hemoglobin levels and those estimated based on hematocrit in the context of the 2nd National Study of Human Growth and Development of the Venezuelan Population (SENACREDH. Materials and methods. 6,004 individuals were chosen by a probabilistic multistage cluster sampling representing 7,286,781 inhabitants from North Central Coastal area (Vargas, Carabobo, Capital District, Aragua and Miranda. Means of observed and estimated hemoglobin (hematocrit/3 were compared, using t test for related samples and linear regression. Results. Mean difference between the values of observed and estimated hemoglobin was -0.3446 ±0.0002 (p<0.001; significantly overestimating the hemoglobin values. Regression models of hemoglobin on hematocrit showed an r2=0,87. In order to correct the estimation, we propose a new formula for calculating hemoglobin based on haematocrit values: estimated hemoglobin=(Haematocrit/3.135+ 0.257. Conclusions: There is an overestimation of hemoglobin levels from hematocrit levels and

  5. Trichomonas vaginalis: the adhesins AP51 and AP65 bind heme and hemoglobin. (United States)

    Ardalan, Shahed; Lee, B Craig; Garber, Gary E


    Trichomonas vaginalis is the cause of human trichomoniasis, the most common non-viral sexually transmitted disease worldwide. Although acquisition of iron by binding to host hemoglobin through distinct receptor(s) has been described, no specific heme- or hemoglobin-binding site has been reported in this parasite. To determine the presence of hemoglobin-binding protein(s), membrane proteins were subjected to hemoglobin-affinity chromatography. Eluted proteins were analysed by SDS-PAGE. Two protein bands of 48 and 63 kDa were detected. Competition assay with an excess amount of hemoglobin or hemin in hemoglobin-affinity chromatography could block the 63- and 48-kDa bands, respectively. Further analysis by mass spectrometry indicated that the 48- and 63-kDa proteins had identity with two T. vaginalis adhesins: AP51 and AP65, respectively. This study confirms the existence of multifunctional proteins in T. vaginalis, and suggested that AP51 and AP65, besides serving as adhesion molecules, could also act as heme- and hemoglobin-binding proteins.

  6. Mutational analysis of hemoglobin binding and heme utilization by a bacterial hemoglobin receptor. (United States)

    Fusco, W G; Choudhary, N R; Council, S E; Collins, E J; Leduc, I


    Iron is an essential nutrient for most living organisms. To acquire iron from their environment, Gram-negative bacteria use TonB-dependent transporters that bind host proteins at the bacterial surface and transport iron or heme to the periplasm via the Ton machinery. TonB-dependent transporters are barrel-shaped outer membrane proteins with 22 transmembrane domains, 11 surface-exposed loops, and a plug domain that occludes the pore. To identify key residues of TonB-dependent transporters involved in hemoglobin binding and heme transport and thereby locate putative protective epitopes, the hemoglobin receptor of Haemophilus ducreyi HgbA was used as a model of iron/heme acquisition from hemoglobin. Although all extracellular loops of HgbA are required by H. ducreyi to use hemoglobin as a source of iron/heme, we previously demonstrated that hemoglobin binding by HgbA only involves loops 5 and 7. Using deletion, substitution, and site-directed mutagenesis, we were able to differentiate hemoglobin binding and heme acquisition by HgbA. Deletion or substitution of the GYEAYNRQWWA region of loop 5 and alanine replacement of selected histidines affected hemoglobin binding by HgbA. Conversely, mutation of the phenylalanine in the loop 7 FRAP domain or substitution of the NRQWWA motif of loop 5 significantly abrogated utilization of heme from hemoglobin. Our findings show that hemoglobin binding and heme utilization by a bacterial hemoglobin receptor involve specific motifs of HgbA.

  7. Characterization of Drosophila hemoglobin. Evidence for hemoglobin-mediated respiration in insects. (United States)

    Hankeln, Thomas; Jaenicke, Viviane; Kiger, Laurent; Dewilde, Sylvia; Ungerechts, Guy; Schmidt, Marc; Urban, Joachim; Marden, Michael C; Moens, Luc; Burmester, Thorsten


    In contrast to previous assumptions, the fruit fly Drosophila melanogaster possesses hemoglobin. This respiratory protein forms a monomer of about 17 kDa that is not exported into the hemolymph. Recombinant Drosophila hemoglobin displays a typical hexacoordinated deoxy spectrum and binds oxygen with an affinity of 0.12 torr. Four different hemoglobin transcripts have been identified, which are generated by two distinct promoters of the hemoglobin (glob1) gene but are identical in their coding regions. Putative binding sites for hypoxia-regulated transcription factors have been identified in the gene. Hemoglobin synthesis in Drosophila is mainly associated with the tracheal system and the fat body. This suggests that oxygen supply in insects may be more complex than thought previously and may depend on hemoglobin-mediated oxygen transport and storage in addition to simple diffusion.

  8. Nanobiotechnology for hemoglobin-based blood substitutes. (United States)

    Chang, T M S


    Nanobiotechnology is the assembling of biological molecules into nanodimension complexes. This has been used for the preparation of polyhemoglobin formed by the assembling of hemoglobin molecules into a soluble nanodimension complex. New generations of this approach include the nanobiotechnological assembly of hemoglobin, catalase, and superoxide dismutase into a soluble nanodimension complex. This acts as an oxygen carrier and an antioxidant for those conditions with potential for ischemiareperfusion injuries. Another recent novel approach is the assembling of hemoglobin and fibrinogen into a soluble nanodimension polyhemoglobin-fibrinogen complex that acts as an oxygen carrier with platelet-like activity. This is potentially useful in cases of extensive blood loss requiring massive replacement using blood substitutes, resulting in the need for the replacement of platelets and clotting factors. A further step is the preparation of nanodimension artificial red blood cells that contain hemoglobin and all the enzymes present in red blood cells.

  9. Undetectable Glycosylated Hemoglobin in Autoimmune Hemolytic Anemia


    Mitani, Noriyuki; Taguchi, Akihiko; Sakuragi, Shizu; Matsui, Kumiko; Tanaka, Yoshinori; Matsuda, Kazuhiro; Shinohara, Kenji


    We encountered two cases of autoimmune hemolytic anemia (AIHA) with undetectable glycosylated hemoglobin (HbA1C) level at diagnosis. Hemolytic anemia improved by administration of prednisolone (PSL) and HbA1C became measurable after response.

  10. Optical Marking of Alcohol Induced Hemoglobin Modification

    CERN Document Server

    Vlokh, R; Moroz, O; Nastishin, Yu; Dudok, K; Dudok, T; Grinchishin, N; Nechiporenko, I; Hul, A


    It has been shown that conformational modifications of Hb induced by ethanol consumption can be visualized in optical spectra studying oxygenation kinetics of hemoglobin or mixing hemoglobin with Cibacron blue dye. Better dye affinity of blood proteins extracted from alcoholised rats with respect to those from non-alcoholised ones confirms that ethanol and its metabolites induce structural pathologies in blood protein molecules. The detected changes for the case of the posterity of intoxicated animals may be explained as a post-translation modification, as well as a disturbance of the structure and function of tissue cellular gene mechanism for the blood creation. It is established that alcohol intake during first four months leads to the decrease of fractional weight of oxyhemoglobin and to the increase of methemoglobin amount in blood. Further alcohol consumption is accompanied by recovering of the normal level of hemoglobin derivatives in blood. Normalization of the fractional weight of hemoglobin derivati...

  11. Hemoglobins, programmed cell death and somatic embryogenesis. (United States)

    Hill, Robert D; Huang, Shuanglong; Stasolla, Claudio


    Programmed cell death (PCD) is a universal process in all multicellular organisms. It is a critical component in a diverse number of processes ranging from growth and differentiation to response to stress. Somatic embryogenesis is one such process where PCD is significantly involved. Nitric oxide is increasingly being recognized as playing a significant role in regulating PCD in both mammalian and plant systems. Plant hemoglobins scavenge NO, and evidence is accumulating that events that modify NO levels in plants also affect hemoglobin expression. Here, we review the process of PCD, describing the involvement of NO and plant hemoglobins in the process. NO is an effector of cell death in both plants and vertebrates, triggering the cascade of events leading to targeted cell death that is a part of an organism's response to stress or to tissue differentiation and development. Expression of specific hemoglobins can alter this response in plants by scavenging the NO, thus, interrupting the death process. Somatic embryogenesis is used as a model system to demonstrate how cell-specific expression of different classes of hemoglobins can alter the embryogenic process, affecting hormone synthesis, cell metabolite levels and genes associated with PCD and embryogenic competence. We propose that plant hemoglobins influence somatic embryogenesis and PCD through cell-specific expression of a distinct plant hemoglobin. It is based on the premise that both embryogenic competence and PCD are strongly influenced by cellular NO levels. Increases in cellular NO levels result in elevated Zn(2+) and reactive-oxygen species associated with PCD, but they also result in decreased expression of MYC2, a transcription factor that is a negative effector of indoleacetic acid synthesis, a hormone that positively influences embryogenic competence. Cell-specific hemoglobin expression reduces NO levels as a result of NO scavenging, resulting in cell survival.

  12. Role of Noninvasive Hemoglobin Monitoring in Trauma (United States)


    AFRL-SA-WP-SR-2015-0002 Role of Noninvasive Hemoglobin Monitoring in Trauma Betty J. Tsuei, MD; Dennis J. Hanseman, PhD...W. Gerlach, USAF, MC U.S. Air Force School of Aerospace Medicine, Center for the Sustainment of Trauma and Readiness Skills March 2015...August 2012 – August 2013 4. TITLE AND SUBTITLE Role of Noninvasive Hemoglobin Monitoring in Trauma 5a. CONTRACT NUMBER FA8650-12-2-6B14 5b

  13. Stabilization of acyclic water tetramer in a copper(II) malonate framework structure. (United States)

    Deshpande, Megha S; Kumbhar, Avinash S; Näther, Christian


    Copper(II) complex [Cu(dpq)(mal)(H(2)O)]·3H(2)O (1) (dpq = dipyrido-[3,2-d:2',3'-f]-quinoxaline, mal = malonato) was synthesized and characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis and single-crystal X-ray crystallography. The single-crystal X-ray structure of 1 reveals a square pyramidal structure, with the dipyrido-[3,2-d:2',3'-f]-quinoxaline and malonato at the equatorial positions and a water molecule at the axial position. The molecule acts as a building block generating a supramolecular three-dimensional metal-organic framework (MOF) encapsulating metal linked acyclic water tetramer. The H-bonding capacity of malonato and the π-π stacking interactions of dipyrido-[3,2-d:2',3'-f]-quinoxaline further reinforce the framework. The copper(II) bound hydroxyl group is demonstrated to mediate hydrolytic cleavage of plasmid pBR322 DNA under dark conditions.

  14. Formation of Nitrogenase NifDK Tetramers in the Mitochondria of Saccharomyces cerevisiae. (United States)

    Burén, Stefan; Young, Eric M; Sweeny, Elizabeth A; López-Torrejón, Gema; Veldhuizen, Marcel; Voigt, Christopher A; Rubio, Luis M


    Transferring the prokaryotic enzyme nitrogenase into a eukaryotic host with the final aim of developing N2 fixing cereal crops would revolutionize agricultural systems worldwide. Targeting it to mitochondria has potential advantages because of the organelle's high O2 consumption and the presence of bacterial-type iron-sulfur cluster biosynthetic machinery. In this study, we constructed 96 strains of Saccharomyces cerevisiae where transcriptional units comprising nine Azotobacter vinelandii nif genes (nifHDKUSMBEN) were integrated into the genome. Two combinatorial libraries of nif gene clusters were constructed: a library of mitochondrial leading sequences consisting of 24 clusters within four subsets of nif gene expression strength, and an expression library of 72 clusters with fixed mitochondrial leading sequences and nif expression levels assigned according to factorial design. In total, 29 promoters and 18 terminators were combined to adjust nif gene expression levels. Expression and mitochondrial targeting was confirmed at the protein level as immunoblot analysis showed that Nif proteins could be efficiently accumulated in mitochondria. NifDK tetramer formation, an essential step of nitrogenase assembly, was experimentally proven both in cell-free extracts and in purified NifDK preparations. This work represents a first step towards obtaining functional nitrogenase in the mitochondria of a eukaryotic cell.

  15. Formation of Nitrogenase NifDK Tetramers in the Mitochondria of Saccharomyces cerevisiae (United States)


    Transferring the prokaryotic enzyme nitrogenase into a eukaryotic host with the final aim of developing N2 fixing cereal crops would revolutionize agricultural systems worldwide. Targeting it to mitochondria has potential advantages because of the organelle’s high O2 consumption and the presence of bacterial-type iron–sulfur cluster biosynthetic machinery. In this study, we constructed 96 strains of Saccharomyces cerevisiae in which transcriptional units comprising nine Azotobacter vinelandii nif genes (nifHDKUSMBEN) were integrated into the genome. Two combinatorial libraries of nif gene clusters were constructed: a library of mitochondrial leading sequences consisting of 24 clusters within four subsets of nif gene expression strength, and an expression library of 72 clusters with fixed mitochondrial leading sequences and nif expression levels assigned according to factorial design. In total, 29 promoters and 18 terminators were combined to adjust nif gene expression levels. Expression and mitochondrial targeting was confirmed at the protein level as immunoblot analysis showed that Nif proteins could be efficiently accumulated in mitochondria. NifDK tetramer formation, an essential step of nitrogenase assembly, was experimentally proven both in cell-free extracts and in purified NifDK preparations. This work represents a first step toward obtaining functional nitrogenase in the mitochondria of a eukaryotic cell. PMID:28221768

  16. Hemoglobin concentration determination based on near infrared spatially resolved transmission spectra (United States)

    Zhang, Linna; Li, Gang; Lin, Ling


    Spatially resolved diffuse reflectance spectroscopy method has been proved to be more effective than single point spectroscopy method in the experiment to predict the concentration of the Intralipid diluted solutions. However, Intralipid diluted solution is simple, cannot be the representative of turbid liquids. Blood is a natural and meaningful turbid liquid, more complicate. Hemoglobin is the major constituent of the whole blood. And hemoglobin concentration is commonly used in clinical medicine to diagnose many diseases. In this paper, near infrared spatially resolved transmission spectra (NIRSRTS) and Partial Least Square Regression (PLSR) were used to predict the hemoglobin concentration of human blood. The results showed the prediction ability for hemoglobin concentration of the proposed method is better than single point transmission spectroscopy method. This paper demonstrated the feasibility of the spatially resolved diffuse reflectance spectroscopy method for practical liquid composition analysis. This research provided a new thinking of practical turbid liquid composition analysis.

  17. Hemoglobin levels in normal Filipino pregnant women. (United States)

    Kuizon, M D; Natera, M G; Ancheta, L P; Platon, T P; Reyes, G D; Macapinlac, M P


    The hemoglobin concentrations during pregnancy in Filipinos belonging to the upper income group, who were prescribed 105 mg elemental iron daily, and who had acceptable levels of transferrin saturation, were examined in an attempt to define normal levels. The hemoglobin concentrations for each trimester followed a Gaussian distribution. The hemoglobin values equal to the mean minus one standard deviation were 11.4 gm/dl for the first trimester and 10.4 gm/dl for the second and third trimesters. Using these values as the lower limits of normal, in one group of pregnant women the prevalence of anemia during the last two trimesters was found lower than that obtained when WHO levels for normal were used. Groups of women with hemoglobin of 10.4 to 10.9 gm/dl (classified anemic by WHO criteria but normal in the present study) and those with 11.0 gm/dl and above could not be distinguished on the basis of their serum ferritin levels nor on the degree of decrease in their hemoglobin concentration during pregnancy. Many subjects in both groups, however, had serum ferritin levels less than 12 ng/ml which indicate poor iron stores. It might be desirable in future studies to determine the hemoglobin cut-off point that will delineate subjects who are both non-anemic and adequate in iron stores using serum ferritin levels as criterion for the latter.

  18. Noninvasive hemoglobin monitoring: how accurate is enough? (United States)

    Rice, Mark J; Gravenstein, Nikolaus; Morey, Timothy E


    Evaluating the accuracy of medical devices has traditionally been a blend of statistical analyses, at times without contextualizing the clinical application. There have been a number of recent publications on the accuracy of a continuous noninvasive hemoglobin measurement device, the Masimo Radical-7 Pulse Co-oximeter, focusing on the traditional statistical metrics of bias and precision. In this review, which contains material presented at the Innovations and Applications of Monitoring Perfusion, Oxygenation, and Ventilation (IAMPOV) Symposium at Yale University in 2012, we critically investigated these metrics as applied to the new technology, exploring what is required of a noninvasive hemoglobin monitor and whether the conventional statistics adequately answer our questions about clinical accuracy. We discuss the glucose error grid, well known in the glucose monitoring literature, and describe an analogous version for hemoglobin monitoring. This hemoglobin error grid can be used to evaluate the required clinical accuracy (±g/dL) of a hemoglobin measurement device to provide more conclusive evidence on whether to transfuse an individual patient. The important decision to transfuse a patient usually requires both an accurate hemoglobin measurement and a physiologic reason to elect transfusion. It is our opinion that the published accuracy data of the Masimo Radical-7 is not good enough to make the transfusion decision.

  19. Sodium Chloride interaction with solvated and crystalline cellulose : sodium ion affects the tetramer and fibril in aqueous solution

    CERN Document Server

    Bellesia, Giovanni


    Inorganic salts are a natural component of biomass which have a significant effect on the product yields from a variety of biomass conversion processes. Understanding their effect on biomass at the microscopic level can help discover their mechanistic role. We present a study of the effect of aqueous sodium chloride (NaCl) on the largest component of biomass, cellulose, focused on the thermodynamic and structural effect of a sodium ion on the cellulose tetramer, and fibril. Replica exchange molecular dynamics simulations of a cellulose tetramer reveal a number of preferred cellulose-Na contacts and bridging positions. Large scale MD simulations on a model cellulose fibril find that Na+ perturbs the hydroxymethyl rotational state population and consequently disrupts the "native" hydrogen bonding network.

  20. X-Ray Crystallographic Analysis, EPR Studies, and Computational Calculations of a Cu(II) Tetramic Acid Complex (United States)

    Matiadis, Dimitrios; Tsironis, Dimitrios; Stefanou, Valentina; Igglessi–Markopoulou, Olga; McKee, Vickie; Sanakis, Yiannis; Lazarou, Katerina N.


    In this work we present a structural and spectroscopic analysis of a copper(II) N-acetyl-5-arylidene tetramic acid by using both experimental and computational techniques. The crystal structure of the Cu(II) complex was determined by single crystal X-ray diffraction and shows that the copper ion lies on a centre of symmetry, with each ligand ion coordinated to two copper ions, forming a 2D sheet. Moreover, the EPR spectroscopic properties of the Cu(II) tetramic acid complex were also explored and discussed. Finally, a computational approach was performed in order to obtain a detailed and precise insight of product structures and properties. It is hoped that this study can enrich the field of functional supramolecular systems, giving place to the formation of coordination-driven self-assembly architectures. PMID:28316540

  1. Generation of functional HLA-DR*1101 tetramers receptive for loading with pathogen or tumour derived synthetic peptides

    Directory of Open Access Journals (Sweden)

    Protti Maria


    Full Text Available Abstract Background MHC class I-peptide tetramers are currently utilised to characterize CD8+ T cell responses at single cell level. The generation and use of MHC class II tetramers to study antigen-specific CD4+ T cells appears less straightforward. Most MHC class II tetramers are produced with a homogeneously built-in peptide, reducing greatly their flexibility of use. We attempted the generation of "empty" functional HLA-DR*1101 tetramers, receptive for loading with synthetic peptides by incubation. No such reagent is in fact available for this HLA-DR allele, one of the most frequent in the Caucasian population. Results We compared soluble MHC class II-immunoglobulin fusion proteins (HLA-DR*1101-Ig with soluble MHC class II protein fused with an optimised Bir site for enzymatic biotynilation (HLA-DR*1101-Bir, both produced in insect cells. The molecules were multimerised by binding fluorochrome-protein A or fluorochrome-streptavidin, respectively. We find that HLA-DR*1101-Bir molecules are superior to the HLA-DR*1101-Ig ones both in biochemical and functional terms. HLA-DR*1101-Bir molecules can be pulsed with at least three different promiscuous peptide epitopes, derived from Tetanus Toxoid, influenza HA and the tumour associated antigen MAGE-3 respectively, to stain specific CD4+ T cells. Both staining temperature and activation state of CD4+ T cells are critical for the binding of peptide-pulsed HLA-DR*1101-Bir to the cognate TCR. Conclusion It is therefore possible to generate a soluble recombinant HLA-DR*1101 backbone that is receptive for loading with different peptides to stain specific CD4+ T cells. As shown for other HLA-DR alleles, we confirm that not all the strategies to produce soluble HLA-DR*1101 multimers are equivalent.

  2. Sodium Chloride interaction with solvated and crystalline cellulose : sodium ion affects the tetramer and fibril in aqueous solution


    Bellesia, Giovanni; Gnanakaran, S.


    Inorganic salts are a natural component of biomass which have a significant effect on the product yields from a variety of biomass conversion processes. Understanding their effect on biomass at the microscopic level can help discover their mechanistic role. We present a study of the effect of aqueous sodium chloride (NaCl) on the largest component of biomass, cellulose, focused on the thermodynamic and structural effect of a sodium ion on the cellulose tetramer, and fibril. Replica exchange m...

  3. 21 CFR 864.7470 - Glycosylated hemoglobin assay. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Glycosylated hemoglobin assay. 864.7470 Section... Glycosylated hemoglobin assay. (a) Identification. A glycosylated hemoglobin assay is a device used to measure the glycosylated hemoglobins (A1a, A1b, and A1c) in a patient's blood by a column...

  4. 21 CFR 864.7400 - Hemoglobin A2 assay. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hemoglobin A2 assay. 864.7400 Section 864.7400...) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Kits and Packages § 864.7400 Hemoglobin A2 assay. (a) Identification. A hemoglobin A2 assay is a device used to determine the hemoglobin A2...

  5. 21 CFR 864.7440 - Electrophoretic hemoglobin analysis system. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Electrophoretic hemoglobin analysis system. 864....7440 Electrophoretic hemoglobin analysis system. (a) Identification. An electrophoretic hemoglobin... hemoglobin types as an aid in the diagnosis of anemia or erythrocytosis (increased total red cell mass)...

  6. 21 CFR 864.7500 - Whole blood hemoglobin assays. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Whole blood hemoglobin assays. 864.7500 Section... blood hemoglobin assays. (a) Identification. A whole blood hemoglobin assay is a device consisting or... hemoglobin content of whole blood for the detection of anemia. This generic device category does not...

  7. 21 CFR 864.7415 - Abnormal hemoglobin assay. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Abnormal hemoglobin assay. 864.7415 Section 864... hemoglobin assay. (a) Identification. An abnormal hemoglobin assay is a device consisting of the reagents... hemoglobin types. (b) Classification. Class II (performance standards)....

  8. 21 CFR 866.5470 - Hemoglobin immunological test system. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hemoglobin immunological test system. 866.5470... Hemoglobin immunological test system. (a) Indentification. A hemoglobin immunological test system is a device... hemoglobin (the oxygen-carrying pigment in red blood cells) in blood, urine, plasma, or other body...

  9. Methylglyoxal-induced modifications of hemoglobin: structural and functional characteristics. (United States)

    Bose, Tania; Bhattacherjee, Abhishek; Banerjee, Sauradipta; Chakraborti, Abhay Sankar


    Methylglyoxal (MG) reacts with proteins to form advanced glycation end products (AGEs). Although hemoglobin modification by MG is known, the modified protein is not yet characterized. We have studied the nature of AGE formed by MG on human hemoglobin (HbA(0)) and its effect on structure and function of the protein. After reaction of HbA(0) with MG, the modified protein (MG-Hb) was separated and its properties were compared with those of the unmodified protein HbA(0). As shown by MALDI-mass spectrometry, MG converted Arg-92α and Arg-104β to hydroimidazolones in MG-Hb. Compared to HbA(0), MG-Hb exhibited decreased absorbance around 280nm, reduced tryptophan fluorescence (excitation 285nm) and increased α-helix content. However, MG modification did not change the quaternary structure of the heme protein. MG-Hb appeared to be more thermolabile than HbA(0). The modified protein was found to be more effective than HbA(0) in H(2)O(2)-mediated iron release and oxidative damages involving Fenton reaction. MG-Hb exhibited less peroxidase activity and more esterase activity than HbA(0). MG-induced structural and functional changes of hemoglobin may enhance oxidative stress and associated complications, particularly in diabetes mellitus with increased level of MG.

  10. Regulation of the fetal hemoglobin silencing factor BCL11A (United States)

    Basak, Anindita; Sankaran, Vijay G.


    The clinical severity of sickle cell disease and β-thalassemia, the major disorders of β-globin, can be ameliorated by increased production of fetal hemoglobin (HbF). Here, we provide a brief overview of the fetal-to-adult hemoglobin switch that occurs in humans shortly after birth and review our current understanding of one of the most potent known regulators of this switching process, the multiple zinc finger–containing transcription factor BCL11A. Originally identified in genome-wide association studies, multiple orthogonal lines of evidence have validated BCL11A as a key regulator of hemoglobin switching and as a promising therapeutic target for HbF induction. We discuss recent studies that have highlighted its importance in silencing the HbF-encoding genes and discuss opportunities that exist to further understand the regulation of BCL11A and its mechanism of action, which could provide new insight into opportunities to induce HbF for therapeutic purposes. PMID:26963603

  11. Crystal Structure of E. coli RecE Protein Reveals a Toroidal Tetramer for Processing Double-Stranded DNA Breaks

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jinjin; Xing, Xu; Herr, Andrew B.; Bell, Charles E.; (OSU); (UCIN)


    Escherichia coli RecE protein is part of the classical RecET recombination system that has recently been used in powerful new methods for genetic engineering. RecE binds to free double-stranded DNA (dsDNA) ends and processively digests the 5{prime}-ended strand to form 5{prime}-mononucleotides and a 3{prime}-overhang that is a substrate for single strand annealing promoted by RecT. Here, we report the crystal structure of the C-terminal nuclease domain of RecE at 2.8 {angstrom} resolution. RecE forms a toroidal tetramer with a central tapered channel that is wide enough to bind dsDNA at one end, but is partially plugged at the other end by the C-terminal segment of the protein. Four narrow tunnels, one within each subunit of the tetramer, lead from the central channel to the four active sites, which lie about 15 {angstrom} from the channel. The structure, combined with mutational studies, suggests a mechanism in which dsDNA enters through the open end of the central channel, the 5{prime}-ended strand passes through a tunnel to access one of the four active sites, and the 3{prime}-ended strand passes through the plugged end of the channel at the back of the tetramer.

  12. The renal handling of hemoglobin. I. Glomerular filtration. (United States)

    Bunn, H F; Esham, W T; Bull, R W


    The glomerular filtration of hemoglobin (alpha(2)beta(2)) was studied under conditions in which its dissociation into alphabeta dimers was experimentally altered. Rats receiving hemoglobin treated with the sulfhydryl reagent bis(N-maleimidomethyl) ether (BME) showed a much lower renal excretion and prolonged plasma survival as compared with animals injected with untreated hemoglobin. Plasma disappearance was also prolonged in dogs receiving BME hemoglobin. Gel filtration data indicated that under physiological conditions, BME hemoglobin had impaired subunit dissociation. In addition, BME hemoglobin showed a very high oxygen affinity and a decreased rate of auto-oxidation. Glomerular filtration was enhanced under conditions which favor the dissociation of hemoglobin into dimers. Cat hemoglobin, which forms subunits much more extensively than canine hemoglobin, was excreted more readily by the rat kidney. The renal uptake of (59)Fe hemoglobin injected intra-arterially into rabbits varied inversely with the concentration of the injected dose.

  13. Polyethylene Glycol Camouflaged Earthworm Hemoglobin (United States)

    Moges, Selamawit; Nacharaju, Parimala; Roche, Camille; Dantsker, David; Palmer, Andre; Friedman, Joel M.


    Nearly 21 million components of blood and whole blood and transfused annually in the United States, while on average only 13.6 million units of blood are donated. As the demand for Red Blood Cells (RBCs) continues to increase due to the aging population, this deficit will be more significant. Despite decades of research to develop hemoglobin (Hb) based oxygen (O2) carriers (HBOCs) as RBC substitutes, there are no products approved for clinical use. Lumbricus terrestris erythrocruorin (LtEc) is the large acellular O2 carrying protein complex found in the earthworm Lumbricus terrestris. LtEc is an extremely stable protein complex, resistant to autoxidation, and capable of transporting O2 to tissue when transfused into mammals. These characteristics render LtEc a promising candidate for the development of the next generation HBOCs. LtEc has a short half-life in circulation, limiting its application as a bridge over days, until blood became available. Conjugation with polyethylene glycol (PEG-LtEc) can extend LtEc circulation time. This study explores PEG-LtEc pharmacokinetics and pharmacodynamics. To study PEG-LtEc pharmacokinetics, hamsters instrumented with the dorsal window chamber were subjected to a 40% exchange transfusion with 10 g/dL PEG-LtEc or LtEc and followed for 48 hours. To study the vascular response of PEG-LtEc, hamsters instrumented with the dorsal window chamber received multiple infusions of 10 g/dL PEG-LtEc or LtEc solution to increase plasma LtEc concentration to 0.5, then 1.0, and 1.5 g/dL, while monitoring the animals’ systemic and microcirculatory parameters. Results confirm that PEGylation of LtEc increases its circulation time, extending the half-life to 70 hours, 4 times longer than that of unPEGylated LtEc. However, PEGylation increased the rate of LtEc oxidation in vivo. Vascular analysis verified that PEG-LtEc showed the absence of microvascular vasoconstriction or systemic hypertension. The molecular size of PEG-LtEc did not change the

  14. Hemoglobin redux: combining neutron and X-ray diffraction with mass spectrometry to analyse the quaternary state of oxidized hemoglobins. (United States)

    Mueser, Timothy C; Griffith, Wendell P; Kovalevsky, Andrey Y; Guo, Jingshu; Seaver, Sean; Langan, Paul; Hanson, B Leif


    Improvements in neutron diffraction instrumentation are affording the opportunity to re-examine the structures of vertebrate hemoglobins and to interrogate proton and solvent position changes between the different quaternary states of the protein. For hemoglobins of unknown primary sequence, structural studies of cyanomethemoglobin (CNmetHb) are being used to help to resolve sequence ambiguity in the mass spectra. These studies have also provided additional structural evidence for the involvement of oxidized hemoglobin in the process of erythrocyte senescence. X-ray crystal studies of Tibetan snow leopard CNmetHb have shown that this protein crystallizes in the B state, a structure with a more open dyad, which possibly has relevance to RBC band 3 protein binding and erythrocyte senescence. R-state equine CNmetHb crystal studies elaborate the solvent differences in the switch and hinge region compared with a human deoxyhemoglobin T-state neutron structure. Lastly, comparison of histidine protonation between the T and R state should enumerate the Bohr-effect protons.

  15. Hemoglobin redux: combining neutron and X-ray diffraction with mass spectrometry to analyse the quaternary state of oxidized hemoglobins

    Energy Technology Data Exchange (ETDEWEB)

    Mueser, Timothy C., E-mail:; Griffith, Wendell P. [Department of Chemistry, University of Toledo, Toledo, OH 43606 (United States); Kovalevsky, Andrey Y. [Bioscience Division, MS M888, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Guo, Jingshu; Seaver, Sean [Department of Chemistry, University of Toledo, Toledo, OH 43606 (United States); Langan, Paul [Department of Chemistry, University of Toledo, Toledo, OH 43606 (United States); Bioscience Division, MS M888, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Hanson, B. Leif [Department of Chemistry, University of Toledo, Toledo, OH 43606 (United States)


    X-ray and neutron diffraction studies of cyanomethemoglobin are being used to evaluate the structural waters within the dimer–dimer interface involved in quaternary-state transitions. Improvements in neutron diffraction instrumentation are affording the opportunity to re-examine the structures of vertebrate hemoglobins and to interrogate proton and solvent position changes between the different quaternary states of the protein. For hemoglobins of unknown primary sequence, structural studies of cyanomethemoglobin (CNmetHb) are being used to help to resolve sequence ambiguity in the mass spectra. These studies have also provided additional structural evidence for the involvement of oxidized hemoglobin in the process of erythrocyte senescence. X-ray crystal studies of Tibetan snow leopard CNmetHb have shown that this protein crystallizes in the B state, a structure with a more open dyad, which possibly has relevance to RBC band 3 protein binding and erythrocyte senescence. R-state equine CNmetHb crystal studies elaborate the solvent differences in the switch and hinge region compared with a human deoxyhemoglobin T-state neutron structure. Lastly, comparison of histidine protonation between the T and R state should enumerate the Bohr-effect protons.

  16. Glycated hemoglobin in camel: Minimal correlation with blood glucose level

    Directory of Open Access Journals (Sweden)

    Bazzi Mohammad D.


    Full Text Available Glucose and glycated hemoglobin (Hb in the blood of camel (Camelus dromedarius and cow (Bos taurus were analyzed and compared with human values. Camel displayed high blood glucose concentration (9.7±2.8 mM but a low level of glycated-Hb (3.4± 0.23%.Cow blood samples did not show sufficient variations in glucose concentrations (5.7±0.73 mM or glycated Hb levels (3.2± 0.11% compared to human values. The low glycation of camel Hb at higher glucose concentrations suggest that certain factors protect the Hb from glycation at high glucose concentrations. Camel Hb also exhibited a higher electrophoretic mobility than normal hemoglobin of human or cow. Camel Hb migrated at a rate corresponding to that of human Hb-C. Bioinformatics tools were used to explore the biochemical basis for the difference in camel Hb migratory position and its apparent resistance to glycation.

  17. A new hemoglobin gene from soybean: a role for hemoglobin in all plants

    DEFF Research Database (Denmark)

    Anderson, C R; Jensen, E O; LLewellyn, D J


    indicate that this new gene is a nonsymbiotic legume hemoglobin. The finding of this gene in legumes and similar genes in other species strengthens our previous suggestion that genomes of all plants contain hemoglobin genes. The specialized leghemoglobin gene family may have arisen from a preexisting...

  18. S100A9 tetramers, which are ligands of CD85j, increase the ability of MVAHIV-primed NK cells to control HIV infection

    Directory of Open Access Journals (Sweden)

    Uriel eMoreno-Nieves1


    Full Text Available Natural Killer (NK cells are the major antiviral effector population of the innate immune system. We previously found that S100A9 is a novel ligand of the receptor CD85j and that S100A9 tetramers enhance the anti-HIV activity of NK cells. Also, we found that DCs infected by the HIV vaccine candidate, MVAHIV, prime NK cells to specifically higher control HIV infection in autologous CD4+ T cells. In this study, we analyzed whether stimulation of NK cells by S100A9 tetramers prior the priming by MVAHIV-infected DCs modulates the subsequent anti-HIV activity of NK cells. We found that S100A9 tetramers activate NK cells and that DCs enhance the anti-HIV activity of NK cells. Interestingly, we observed that stimulation of NK cells by S100A9 tetramers, prior the priming, significantly increased the subsequent anti-HIV activity of NK cells; and that the enhanced anti-HIV activity was observed following different conditions of priming, including the MVAHIV-priming. As S100A9 tetramers alone directly increase the anti-HIV activity of NK cells and as this increased anti-HIV activity is also observed following the interaction of NK cells with MVAHIV-infected DCs, we propose S100A9 tetramers as potential adjuvants to stimulate the anti-HIV activity of NK cells.

  19. PIP Water Transport and Its pH Dependence Are Regulated by Tetramer Stoichiometry. (United States)

    Jozefkowicz, Cintia; Sigaut, Lorena; Scochera, Florencia; Soto, Gabriela; Ayub, Nicolás; Pietrasanta, Lía Isabel; Amodeo, Gabriela; González Flecha, F Luis; Alleva, Karina


    Many plasma membrane channels form oligomeric assemblies, and heterooligomerization has been described as a distinctive feature of some protein families. In the particular case of plant plasma membrane aquaporins (PIPs), PIP1 and PIP2 monomers interact to form heterotetramers. However, the biological properties of the different heterotetrameric configurations formed by PIP1 and PIP2 subunits have not been addressed yet. Upon coexpression of tandem PIP2-PIP1 dimers in Xenopus oocytes, we can address, for the first time to our knowledge, the functional properties of single heterotetrameric species having 2:2 stoichiometry. We have also coexpressed PIP2-PIP1 dimers with PIP1 and PIP2 monomers to experimentally investigate the localization and biological activity of each tetrameric assembly. Our results show that PIP2-PIP1 heterotetramers can assemble with 3:1, 1:3, or 2:2 stoichiometry, depending on PIP1 and PIP2 relative expression in the cell. All PIP2-PIP1 heterotetrameric species localize at the plasma membrane and present the same water transport capacity. Furthermore, the contribution of any heterotetrameric assembly to the total water transport through the plasma membrane doubles the contribution of PIP2 homotetramers. Our results also indicate that plasma membrane water transport can be modulated by the coexistence of different tetrameric species and by intracellular pH. Moreover, all the tetrameric species present similar cooperativity behavior for proton sensing. These findings throw light on the functional properties of PIP tetramers, showing that they have flexible stoichiometry dependent on the quantity of PIP1 and PIP2 molecules available. This represents, to our knowledge, a novel regulatory mechanism to adjust water transport across the plasma membrane.

  20. Selective Removal of Hemoglobin from Blood Using Hierarchical Copper Shells Anchored to Magnetic Nanoparticles (United States)

    Wang, Yaokun; Yan, Mingyang


    Hierarchical copper shells anchored on magnetic nanoparticles were designed and fabricated to selectively deplete hemoglobin from human blood by immobilized metal affinity chromatography. Briefly, CoFe2O4 nanoparticles coated with polyacrylic acid were first synthesized by a one-pot solvothermal method. Hierarchical copper shells were then deposited by immobilizing Cu2+ on nanoparticles and subsequently by reducing between the solid CoFe2O4@COOH and copper solution with NaBH4. The resulting nanoparticles were characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectrometry, X-ray photoelectron spectroscopy, and vibrating sample magnetometry. The particles were also tested against purified bovine hemoglobin over a range of pH, contact time, and initial protein concentration. Hemoglobin adsorption followed pseudo-second-order kinetics and reached equilibrium in 90 min. Isothermal data also fit the Langmuir model well, with calculated maximum adsorption capacity 666 mg g−1. Due to the high density of Cu2+ on the shell, the nanoparticles efficiently and selectively deplete hemoglobin from human blood. Taken together, the results demonstrate that the particles with hierarchical copper shells effectively remove abundant, histidine-rich proteins, such as hemoglobin from human blood, and thereby minimize interference in diagnostic and other assays.

  1. Selective Removal of Hemoglobin from Blood Using Hierarchical Copper Shells Anchored to Magnetic Nanoparticles. (United States)

    Liu, Youxun; Wang, Yaokun; Yan, Mingyang; Huang, Juan


    Hierarchical copper shells anchored on magnetic nanoparticles were designed and fabricated to selectively deplete hemoglobin from human blood by immobilized metal affinity chromatography. Briefly, CoFe2O4 nanoparticles coated with polyacrylic acid were first synthesized by a one-pot solvothermal method. Hierarchical copper shells were then deposited by immobilizing Cu(2+) on nanoparticles and subsequently by reducing between the solid CoFe2O4@COOH and copper solution with NaBH4. The resulting nanoparticles were characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectrometry, X-ray photoelectron spectroscopy, and vibrating sample magnetometry. The particles were also tested against purified bovine hemoglobin over a range of pH, contact time, and initial protein concentration. Hemoglobin adsorption followed pseudo-second-order kinetics and reached equilibrium in 90 min. Isothermal data also fit the Langmuir model well, with calculated maximum adsorption capacity 666 mg g(-1). Due to the high density of Cu(2+) on the shell, the nanoparticles efficiently and selectively deplete hemoglobin from human blood. Taken together, the results demonstrate that the particles with hierarchical copper shells effectively remove abundant, histidine-rich proteins, such as hemoglobin from human blood, and thereby minimize interference in diagnostic and other assays.

  2. 胃癌患者血红蛋白的表面增强拉曼光谱分析%Research on Early Diagnosis of Gastric Cancer by the Surface Enhanced Raman Spectroscopy of Human Hemoglobin

    Institute of Scientific and Technical Information of China (English)

    王巍; 潘志峰; 唐伟跃; 李云涛; 范春珍


    胃癌患者能够得到早期诊断对其治疗具有十分重要的意义,疾病状态下的血红蛋白拉曼光谱检测在血液代用品的高铁血红蛋白含量检测中以及血氧饱和定量测定中占很大优势。本实验采用微波加热法制备银胶体粒子,依次对20例胃癌患者和11例健康人的血红蛋白进行表面增强拉曼光谱分析。采用SERS谱峰归属分析结果显示胃癌患者血红蛋白中的酪氨酸、苯丙氨酸和吡咯环的含量均低于正常人。本文还讨论了血红素的分子结构,在血红蛋白和氧气结合的前后,Fe2+分别处于高低自旋态,离子半径也随着与氧结合缩小了0.075 nm从而滑落入卟啉环平面中央的孔隙之中。这种空间的拉伸变化会牵动与铁相连的 F8 H is ,使得珠蛋白中两股螺旋之间空隙缩小,导致将 HC2酪氨酸排挤出空隙。利用这一机理,对血红蛋白1560 cm -1的吸收峰进行研究,证实了胃癌患者酪氨酸含量确实低于正常人。为了能得到更加明显的诊断区分,利用降维的思想,采用主成分分析(PCA )的方法对所有的拉曼光谱进行多元统计分析,得出三维的诊断散点图。为了更加精确的得出诊断准确率,用判别分析得出诊断的灵敏度和特异性分别为90.0%和90.9%,总判别正确率为90.3%。此项研究表明:对氧合血红蛋白的表面增强拉曼光谱诊断分析有希望成为一项新型的胃癌诊断技术应用于医学领域。%Early diagnosis have great positive effect on the treatment of gastric cancer patients .Raman spectroscopy can provide a useful monitor for hemoglobin dynamics .Besides ,Raman spectroscopy has notable advantages in the fields of abnormal hemo-globin diagnosis ,hemoglobin oxygen saturation deter mination and blood methemoglobin analysis .In this paper ,novel silver colloid was synthesized by microwave heated method .The surface enhanced Raman spectrums of

  3. Nitrosyl hemoglobins: EPR above 80 K

    Energy Technology Data Exchange (ETDEWEB)

    Wajnberg, E.; Bemski, G.; El-Jaick, L.J.; Alves, O.C.


    The EPR spectra of nitrosyl hemoglobin and myoglobin in different conditions (native, denatured and lyophilized), as well as of hematin-NO were obtained in the temperature range of 80 K-280 K. There is a substantial and reversible.decrease of the areas of the EPR spectra of all the hemoglobin samples above 150 K. The interpretation of the results implies the existence of two conformational states in thermal equilibrium only one of which is EPR detectable. Thermodynamical parameters are determined for the hexa and penta-coordinated cases. (author). 25 refs, 3 figs.

  4. Immunization with a tetramer derivative of an anti-inflammatory pentapeptide produced by Entamoeba histolytica protects gerbils (Meriones unguiculatus) against experimental amoebic abscess of the liver. (United States)

    Giménez-Scherer, Juan Antonio; Cárdenas, Guadalupe; López-Osuna, Martha; Velázquez, Juan Raymundo; Rico, Guadalupe; Isibasi, Armando; Maldonado, María del Carmen; Morales, María Esther; Fernández-Diez, Jorge; Kretschmer, Roberto R


    Axenically grown Entamoeba histolytica produces a pentapeptide (Met-Gln-Cys-Asn-Ser) with several anti-inflammatory properties, including the inhibition of human monocyte locomotion (Monocyte Locomotion Inhibitory Factor (MLIF)). A construct displays the same effects as the native material. It remains to be seen if MLIF is used, or even produced in vivo by the tissue-invading parasite. If MLIF were to be relevant in invasive amoebiasis, immunizing against it could diminish this parasite advantage and prevent lesions. KLH-linked MLIF mixed with Freund's adjuvant was too aggressive an immunizing material to answer this question. However, immunization with a tetramer of MLIF (but not a scrambled version of MLIF) around a lysine core (MLIF-MAPS), that displays increased antigenicity, yet lacks excessive innate immunity activation, completely protects gerbils against amoebic abscess of the liver caused by the intraportal injection of virulent E. histolytica. Liver abscesses caused by Listeria monocytogenes were not prevented. Invasive E. histolytica may produce the parent protein of MLIF in vivo, and if appropriately cleaved, it may play a role in invasive amoebiasis. MLIF may join new vaccination strategies against amoebiasis.

  5. Formation of a stable RuvA protein double tetramer is required for efficient branch migration in vitro and for replication fork reversal in vivo. (United States)

    Bradley, Alison S; Baharoglu, Zeynep; Niewiarowski, Andrew; Michel, Bénédicte; Tsaneva, Irina R


    In bacteria, RuvABC is required for the resolution of Holliday junctions (HJ) made during homologous recombination. The RuvAB complex catalyzes HJ branch migration and replication fork reversal (RFR). During RFR, a stalled fork is reversed to form a HJ adjacent to a DNA double strand end, a reaction that requires RuvAB in certain Escherichia coli replication mutants. The exact structure of active RuvAB complexes remains elusive as it is still unknown whether one or two tetramers of RuvA support RuvB during branch migration and during RFR. We designed an E. coli RuvA mutant, RuvA2(KaP), specifically impaired for RuvA tetramer-tetramer interactions. As expected, the mutant protein is impaired for complex II (two tetramers) formation on HJs, although the binding efficiency of complex I (a single tetramer) is as wild type. We show that although RuvA complex II formation is required for efficient HJ branch migration in vitro, RuvA2(KaP) is fully active for homologous recombination in vivo. RuvA2(KaP) is also deficient at forming complex II on synthetic replication forks, and the binding affinity of RuvA2(KaP) for forks is decreased compared with wild type. Accordingly, RuvA2(KaP) is inefficient at processing forks in vitro and in vivo. These data indicate that RuvA2(KaP) is a separation-of-function mutant, capable of homologous recombination but impaired for RFR. RuvA2(KaP) is defective for stimulation of RuvB activity and stability of HJ·RuvA·RuvB tripartite complexes. This work demonstrates that the need for RuvA tetramer-tetramer interactions for full RuvAB activity in vitro causes specifically an RFR defect in vivo.

  6. Precision and linearity targets for validation of an IFNγ ELISPOT, cytokine flow cytometry, and tetramer assay using CMV peptides

    Directory of Open Access Journals (Sweden)

    Lyerly Herbert K


    Full Text Available Abstract Background Single-cell assays of immune function are increasingly used to monitor T cell responses in immunotherapy clinical trials. Standardization and validation of such assays are therefore important to interpretation of the clinical trial data. Here we assess the levels of intra-assay, inter-assay, and inter-operator precision, as well as linearity, of CD8+ T cell IFNγ-based ELISPOT and cytokine flow cytometry (CFC, as well as tetramer assays. Results Precision was measured in cryopreserved PBMC with a low, medium, or high response level to a CMV pp65 peptide or peptide mixture. Intra-assay precision was assessed using 6 replicates per assay; inter-assay precision was assessed by performing 8 assays on different days; and inter-operator precision was assessed using 3 different operators working on the same day. Percent CV values ranged from 4% to 133% depending upon the assay and response level. Linearity was measured by diluting PBMC from a high responder into PBMC from a non-responder, and yielded R2 values from 0.85 to 0.99 depending upon the assay and antigen. Conclusion These data provide target values for precision and linearity of single-cell assays for those wishing to validate these assays in their own laboratories. They also allow for comparison of the precision and linearity of ELISPOT, CFC, and tetramer across a range of response levels. There was a trend toward tetramer assays showing the highest precision, followed closely by CFC, and then ELISPOT; while all three assays had similar linearity. These findings are contingent upon the use of optimized protocols for each assay.

  7. High-altitude adaptations in vertebrate hemoglobins

    DEFF Research Database (Denmark)

    Weber, Roy E.


    Vertebrates at high altitude are subjected to hypoxic conditions that challenge aerobic metabolism. O2 transport from the respiratory surfaces to tissues requires matching between the O2 loading and unloading tensions and theO2-affinity of blood, which is an integrated function of hemoglobin......, birds and ectothermic vertebrates at high altitude....

  8. Hemoglobin: A Nitric-Oxide Dioxygenase

    Directory of Open Access Journals (Sweden)

    Paul R. Gardner


    Full Text Available Members of the hemoglobin superfamily efficiently catalyze nitric-oxide dioxygenation, and when paired with native electron donors, function as NO dioxygenases (NODs. Indeed, the NOD function has emerged as a more common and ancient function than the well-known role in O2 transport-storage. Novel hemoglobins possessing a NOD function continue to be discovered in diverse life forms. Unique hemoglobin structures evolved, in part, for catalysis with different electron donors. The mechanism of NOD catalysis by representative single domain hemoglobins and multidomain flavohemoglobin occurs through a multistep mechanism involving O2 migration to the heme pocket, O2 binding-reduction, NO migration, radical-radical coupling, O-atom rearrangement, nitrate release, and heme iron re-reduction. Unraveling the physiological functions of multiple NODs with varying expression in organisms and the complexity of NO as both a poison and signaling molecule remain grand challenges for the NO field. NOD knockout organisms and cells expressing recombinant NODs are helping to advance our understanding of NO actions in microbial infection, plant senescence, cancer, mitochondrial function, iron metabolism, and tissue O2 homeostasis. NOD inhibitors are being pursued for therapeutic applications as antibiotics and antitumor agents. Transgenic NOD-expressing plants, fish, algae, and microbes are being developed for agriculture, aquaculture, and industry.

  9. Insulin-induced lipid binding to hemoglobin

    NARCIS (Netherlands)

    Tomasevic, N; Klappe, K; Hoekstra, D; Niketic, [No Value; Nikolic, M.


    Under hypoglycemic conditions, concomitant hyperinsulinism causes an apparent modification of hemoglobin (Hb) which is manifested by its a aggregation (Niketic et al.. Clin. Chim. Acia 197 (1991) 47). In the present work the causes and mechanisms underlying this Hb modification were Studied. Hemoglo

  10. High-altitude adaptations in vertebrate hemoglobins

    DEFF Research Database (Denmark)

    Weber, Roy E.


    Vertebrates at high altitude are subjected to hypoxic conditions that challenge aerobic metabolism. O2 transport from the respiratory surfaces to tissues requires matching between the O2 loading and unloading tensions and theO2-affinity of blood, which is an integrated function of hemoglobin......, birds and ectothermic vertebrates at high altitude....

  11. Hemoglobin C, S-C, and E Diseases (United States)

    ... Anemia Vitamin Deficiency Anemia Anemia of Chronic Disease Aplastic Anemia Autoimmune Hemolytic Anemia Sickle Cell Disease Hemoglobin C, S- ... Anemia Vitamin Deficiency Anemia Anemia of Chronic Disease Aplastic Anemia Autoimmune Hemolytic Anemia Sickle Cell Disease Hemoglobin C, S- ...

  12. The influence of socioeconomic status on the hemoglobin level and ...

    African Journals Online (AJOL)

    The influence of socioeconomic status on the hemoglobin level and ... using anthropometric measurements and steady-state hemoglobin, of children with ... Social class was assessed using educational attainment and occupation of parents.

  13. Alpha chain hemoglobins with electrophoretic mobility similar to that of hemoglobin S in a newborn screening program

    Directory of Open Access Journals (Sweden)

    Marcilene Rezende Silva


    Full Text Available OBJECTIVE: To characterize alpha-chain variant hemoglobins with electric mobility similar to that of hemoglobin S in a newborn screening program. METHODS: βS allele and alpha-thalassemia deletions were investigated in 14 children who had undefined hemoglobin at birth and an electrophoretic profile similar to that of hemoglobin S when they were six months old. Gene sequencing and restriction enzymes (DdeI, BsaJI, NlaIV, Bsu36I and TaqI were used to identify hemoglobins. Clinical and hematological data were obtained from children who attended scheduled medical visits. RESULTS: The following alpha chain variants were found: seven children with hemoglobin Hasharon [alpha2 47(CE5 Asp>His, HbA2:c.142G>C], all associated with alpha-thalassemia, five with hemoglobin Ottawa [alpha1 15(A13 Gly>Arg, HBA1:c.46G>C], one with hemoglobin St Luke's [alpha1 95(G2 Pro>Arg, HBA1:c.287C>G] and another one with hemoglobin Etobicoke [alpha212 84(F5 Ser>Arg, HBA212:c.255C>G]. Two associations with hemoglobin S were found: one with hemoglobin Ottawa and one with hemoglobin St Luke's. The mutation underlying hemoglobin Etobicoke was located in a hybrid α212 allele in one child. There was no evidence of clinically relevant hemoglobins detected in this study. CONCLUSION: Apparently these are the first cases of hemoglobin Ottawa, St Luke's, Etobicoke and the α212 gene described in Brazil. The hemoglobins detected in this study may lead to false diagnosis of sickle cell trait or sickle cell disease when only isoelectric focusing is used in neonatal screening. Additional tests are necessary for the correct identification of hemoglobin variants.

  14. The histone chaperone Vps75 forms multiple oligomeric assemblies capable of mediating exchange between histone H3-H4 tetramers and Asf1-H3-H4 complexes

    DEFF Research Database (Denmark)

    Hammond, Colin M; Sundaramoorthy, Ramasubramanian; Larance, Mark


    Vps75 is a histone chaperone that has been historically characterized as homodimer by X-ray crystallography. In this study, we present a crystal structure containing two related tetrameric forms of Vps75 within the crystal lattice. We show Vps75 associates with histones in multiple oligomers...... catalysed histone H3 K9 acetylation. In the absence of Asf1 this model can be used to generate a complex consisting of a reconfigured Vps75 tetramer bound to a H3-H4 tetramer. This provides a structural explanation for many of the complexes detected biochemically and illustrates the ability of Vps75....... In the presence of equimolar H3-H4 and Vps75, the major species is a reconfigured Vps75 tetramer bound to a histone H3-H4 tetramer. However, in the presence of excess histones, a Vps75 dimer bound to a histone H3-H4 tetramer predominates. We show the Vps75-H3-H4 interaction is compatible with the histone...

  15. Early diagnosis of sepsis using serum hemoglobin subunit Beta. (United States)

    Yoo, Hayoung; Ku, Sae-Kwang; Kim, Shin-Woo; Bae, Jong-Sup


    The development of new sepsis-specific biomarkers is mandatory to improve the detection and monitoring of the disease. Hemoglobin is the main oxygen and carbon dioxide carrier in cells of the erythroid lineage and is responsible for oxygen delivery to the respiring tissues of the body. Hemoglobin subunit beta (HBβ) is a component of a larger protein called hemoglobin. The aim of this study was to evaluate blood levels of HBβ in septic patients. A prospective study of 82 patients with sepsis was conducted. Furthermore, C57BL/6 mice were subjected to cecal ligation and puncture (CLP) surgery. Alternatively, human umbilical vein endothelial cells (HUVECs) or C57BL/6 mice were exposed to lipopolysaccharide (LPS, 100 ng/ml to HUVECs or 10 mg/kg to mice). The data showed that LPS induced upregulation of the synthesis and secretion of HBβ in LPS-treated HUVECs and in LPS-injected and CLP mice. In patients admitted to the intensive care unit with sepsis, circulating levels of HBβ were significantly high (sepsis, 64.93-114.76 ng/ml, n = 30; severe sepsis, 157.37-268.69 ng/ml, n = 22; septic shock, 309.98-427.03 ng/ml, n = 30) when compared to the levels of control donors (9.76-12.28 ng/ml, n = 21). Patients with septic shock had higher HBβ levels when compared to patients with severe sepsis. Furthermore, the HBβ levels in septic patients were higher than those in healthy volunteers. These results suggest that in septic patients, HBβ blood level is related to the severity of sepsis and may represent a novel endothelial cell dysfunction marker. Moreover, HBβ can be used as a biomarker to determine the severity of sepsis.

  16. 21 CFR 522.1125 - Hemoglobin glutamer-200 (bovine). (United States)


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Hemoglobin glutamer-200 (bovine). 522.1125 Section... § 522.1125 Hemoglobin glutamer-200 (bovine). (a) Specifications. Each 125 milliliter bag contains 13 grams per deciliter of polymerized hemoglobin of bovine origin in modified Lactated Ringer's...

  17. Truncated hemoglobins in actinorhizal nodules of Datisca glomerata

    NARCIS (Netherlands)

    Pawlowski, K.; Jacobsen, K.R.; Alloisio, N.; Denison, R.F.; Klein, M.; Tjepkema, J.D.; Winzer, T.; Sirrenberg, A.; Guan, C.; Berry, A.M.


    Three types of hemoglobins exist in higher plants, symbiotic, non-symbiotic, and truncated hemoglobins. Symbiotic (class II) hemoglobins play a role in oxygen supply to intracellular nitrogen-fixing symbionts in legume root nodules, and in one case ( Parasponia Sp.), a non-symbiotic (class I) hemogl

  18. Truncated hemoglobins in actinorhizal nodules of Datisca glomerata

    NARCIS (Netherlands)

    Pawlowski, K.; Jacobsen, K.R.; Alloisio, N.; Denison, R.F.; Klein, M.; Tjepkema, J.D.; Winzer, T.; Sirrenberg, A.; Guan, C.; Berry, A.M.


    Three types of hemoglobins exist in higher plants, symbiotic, non-symbiotic, and truncated hemoglobins. Symbiotic (class II) hemoglobins play a role in oxygen supply to intracellular nitrogen-fixing symbionts in legume root nodules, and in one case ( Parasponia Sp.), a non-symbiotic (class I)

  19. Bioimaging techniques for subcellular localization of plant hemoglobins and measurement of hemoglobin-dependent nitric oxide scavenging in planta. (United States)

    Hebelstrup, Kim H; Østergaard-Jensen, Erik; Hill, Robert D


    Plant hemoglobins are ubiquitous in all plant families. They are expressed at low levels in specific tissues. Several studies have established that plant hemoglobins are scavengers of nitric oxide (NO) and that varying the endogenous level of hemoglobin in plant cells negatively modulates bioactivity of NO generated under hypoxic conditions or during cellular signaling. Earlier methods for determination of hemoglobin-dependent scavenging in planta were based on measuring activity in whole plants or organs. Plant hemoglobins do not contain specific organelle localization signals; however, earlier reports on plant hemoglobin have demonstrated either cytosolic or nuclear localization, depending on the method or cell type investigated. We have developed two bioimaging techniques: one for visualization of hemoglobin-catalyzed scavenging of NO in specific cells and another for visualization of subcellular localization of green fluorescent protein-tagged plant hemoglobins in transformed Arabidopsis thaliana plants.

  20. Within-host evolution of Pseudomonas aeruginosa toward iron acquisition from hemoglobin in polymicrobial CF infections

    DEFF Research Database (Denmark)

    Khademi, Seyed Mohammad Hossein; Marvig, Rasmus Lykke; Pedersen, Søren Damkiær;


    Bacterial pathogens require iron to survive and colonize a human host but their access to free iron is often limited by iron-withholding process where free iron is bound by proteins such as hemoglobin. Although most pathogens have developed tactics to acquire iron from host proteins, little is kn...

  1. Hemoglobin oxidative stress in cancer. (United States)

    Della Rovere, F; Granata, A; Broccio, M; Zirilli, A; Broccio, G


    The role played by free radicals in carcinogenesis and their relationships with antioxidant pool and cancer have already been shown. Free radicals induce increased membrane permeability through membrane lipid peroxidation, protein oxidation and histamine release from mast cells. Free radicals also cause oxyhemoglobin oxidative stress which increases methemoglobin and hemichromes. For this reason, we studied the in vitro formation of methemoglobin at 0' and 90', dosed following the HPLC method, after oxidative stress of blood by means of acetylphenylhydrazine in 40 subjects with cancer and 40 healthy donors. The results showed that methemoglobin formation was highly significant in tumors as compared to controls (P < 0.0001). The statistical analyses we carried out showed that metHb formation is not affected by age, sex, smoking habit, red blood cell number, Hb, Ht or tumor staging. This makes us believe that free radicals alter erythrocyte membrane permeability and predenaturate oxyhemoglobin so that erythrocyte membrane becomes more susceptible to new oxidative stress. This caused the abnormal response we found. Our results clearly underline the role played by free radicals in tumorous disease and provide a successful and easy method to detect early, even in a pre-clinical stage, the presence of tumorous alterations in the human body.

  2. The SAS-5 N-terminal domain is a tetramer, with implications for centriole assembly in C. elegans. (United States)

    Shimanovskaya, Ekaterina; Qiao, Renping; Lesigang, Johannes; Dong, Gang


    The centriole is a conserved microtubule-based organelle essential for both centrosome formation and cilium biogenesis. It has a unique 9-fold symmetry and its assembly is governed by at least five component proteins (SPD-2, ZYG-1, SAS-5, SAS-6 and SAS-4), which are recruited in a hierarchical order. Recently published structural studies of the SAS-6 N-terminal domain have greatly advanced our understanding of the mechanisms of centriole assembly. However, it remains unclear how the weak interaction between the SAS-6 N-terminal head groups could drive the assembly of a closed ring-like structure, and what determines the stacking of multiple rings on top one another in centriole duplication. We recently reported that SAS-5 binds specifically to a very narrow region of the SAS-6 central coiled coil through its C-terminal domain (CTD, residues 391-404). Here, we further demonstrate by both static light scattering and small angle X-ray scattering that the SAS-5 N-terminal domain (NTD, residues 1-260) forms a tetramer. Specifically, we found that the tetramer is formed by SAS-5 residues 82-260, whereas residues 1-81 are intrinsically disordered. Taking these results together, we propose a working model for SAS-5-mediated assembly of the multi-layered central tube structure.

  3. Spin state transition in the active center of the hemoglobin molecule: DFT + DMFT study (United States)

    Novoselov, D.; Korotin, Dm. M.; Anisimov, V. I.


    An ab initio study of electronic and spin configurations of the iron ion in the active center of the human hemoglobin molecule is presented. With a combination of the Density Functional Theory (DFT) method and the Dynamical Mean Field Theory (DMFT) approach, the spin state transition description in the iron ion during the oxidation process is significantly improved in comparison with previous attempts. It was found that the origin of the iron ion local moment behavior both for the high-spin and for the low-spin states in the hemoglobin molecule is caused by the presence of a mixture of several atomic states with comparable statistical probability.

  4. Mass spectrometric identification of hemoglobin modifications induced by nitrosobenzene. (United States)

    Di Girolamo, Francesco; Campanella, Luigi; Samperi, Roberto; Bachi, Angela


    Aniline and nitrobenzene (NB) are widely used industrial chemicals. Early effects of aniline toxicity include methemoglobin formation and damage to erythrocytes (Jenkins, F.P., 1972. The no-effect dose of anilne in human subjects and a comparison of aniline toxicity in man and rat. Food Cosmet. Toxicol. 10, 671-679; Bus, J.S., Popp, J.A., 1987. Perspectives on the mechanism of action of the splenic toxicity of aniline and structurally-related. Food Chem. Toxicol. 25, 619-627). In this report, we describe an analytical method, based on LC techniques and mass spectrometry, which could help in monitoring the exposure to aniline and NB. In particular, we describe and characterize the formation of specific adducts during an in vitro reaction of nitrosobenzene (NOB), the main metabolite of aniline and NB, and human hemoglobin.

  5. Wavelength selection based on two-dimensional correlation spectroscopy: application to noninvasive hemoglobin measurement by dynamic spectrum (United States)

    Zhang, Shengzhao; Zhang, Linna; Li, Zhe; Li, Gang; Lin, Ling


    Dynamic spectrum (DS) method is one of the noninvasive approaches to measure the concentration of components in human blood based on the application of photoplethysmogram (PPG). One of the targets of the DS method is to predict the hemoglobin concentration in human blood noninvasively. In previous works, the usually used wavelength in the spectrum is 600-1100 nm which is regarded as the analysis "window" in human tissues. Optimum wavelengths for measurements of hemoglobin concentration have not been investigated yet. In order to improve the precision and reliability of hemoglobin measurements, a method for wavelength selection based on two-dimension (2D) correlation spectroscopy has been studied in this paper. By analyzing the 2D correlation spectroscopy which is generated by the DS data from subject with different blood hemoglobin concentrations, the wavelength bands which are sensible to hemoglobin concentrations in DS can be found. We developed calibration models between the DS data and hemoglobin concentration based on data from 57 subjects. The correlation coefficient is 0.68 in the test set of the model using the whole wavelength band (600-1100nm), while in the test set of the model using the selected wavelength band (850- 950nm) the correlation coefficient is 0.87. Results show the feasibility of wavelength selection utilizing 2Dcorrelation spectroscopy.

  6. Magnetic Nanospheres Encapsulated by Mesoporous Copper Oxide Shell for Selective Isolation of Hemoglobin. (United States)

    Guo, Zhi-Yong; Zhang, Yue; Zhang, Dan-Dan; Shu, Yang; Chen, Xu-Wei; Wang, Jian-Hua


    A novel strategy for the preparation of magnetic nanospheres encapsulated by mesoporous copper oxide shell, shortly termed as Fe3O4@mCuO, is reported via the calcination of Cu(NH3)4(NO3)2 into continuous mesoporous CuO shell onto the surface of Fe3O4 nanoparticles. The magnetic nanospheres are characterized to possess stable core-shell structure with a crystalline mesoporous CuO layer, exhibiting a CuO loading content of 25.2 ± 1.1% along with a favorable magnetic susceptibility. Fe3O4@mCuO nanospheres exhibit favorable selectivity on the adsorption of hemoglobin with a high adsorption capacity of up to 1162.5 mg g(-1). After adsorption, the high magnetic susceptibility allows convenient separation of the nanospheres by an external magnet. The retained hemoglobin could be readily recovered by using 0.5% (m/v) sodium dodecyl sulfate (SDS) as stripping reagent, providing a recovery of 78%. Circular dichroism spectra illustrate virtually no change in the conformation of hemoglobin after the process of adsorption/desorption. Fe3O4@mCuO nanospheres are further applied for the selective isolation of hemoglobin from human whole blood, achieving high-purity hemoglobin as demonstrated by SDS-PAGE (polyacrylamide gel electrophoresis) assays.

  7. Hemoglobin adducts of N-substituted aryl compounds in exposure control and risk assessment. (United States)

    Neumann, H G; Birner, G; Kowallik, P; Schütze, D; Zwirner-Baier, I


    Arylamines, nitroarenes, and azo dyes yield a common type of metabolite, the nitroarene, which produces a hydrolyzable adduct with protein and is closely related to the critical, ultimate toxic and genotoxic metabolite. The target dose as measured by hemoglobin adducts in erythrocytes reflects not only the actual uptake from the environment but also an individual's capacity for metabolic activation and is therefore an improved dosimeter for human exposure. The usefulness of hemoglobin adducts in molecular epidemiology is now widely recognized. With regard to risk assessment, many questions need to be answered. The described experiments in rats address some of these questions. The relationship between binding to hemoglobin in erythrocytes and to proteins in plasma has been found to vary considerably for a number of diamines. The fraction of hydrolyzable adducts out of the total protein adducts formed also varies in both compartments. This indicates that the kind of circulating metabolites and their availability in different compartments is compound specific. This has to do with the complex pattern of competing metabolic pathways, and the role of N-acetylation and deacetylation is emphasized. An example of nonlinear dose dependence adds to the complexity. Analysis of hemoglobin adducts reveals interesting insights into prevailing pathways, which not only apply to the chemical, but may also be useful to assess an individual's metabolic properties. In addition, it is demonstrated that the greater part of erythrocytes and benzidine-hemoglobin adducts are eliminated randomly in rats, i.e., following first-order kinetics.

  8. Molecular Mechanism of AHSP-Mediated Stabilization of Alpha-Hemoglobin

    Energy Technology Data Exchange (ETDEWEB)

    Feng,L.; Gell, D.; Zhou, S.; Gu, L.; Kong, Y.; Li, J.; Hu, M.; Yan, N.; Lee, C.; et al.


    Hemoglobin A (HbA), the oxygen delivery system in humans, comprises two alpha and two beta subunits. Free alpha-hemoglobin (alphaHb) is unstable, and its precipitation contributes to the pathophysiology of beta thalassemia. In erythrocytes, the alpha-hemoglobin stabilizing protein (AHSP) binds alphaHb and inhibits its precipitation. The crystal structure of AHSP bound to Fe(II)-alphaHb reveals that AHSP specifically recognizes the G and H helices of alphaHb through a hydrophobic interface that largely recapitulates the alpha1-beta1 interface of hemoglobin. The AHSP-alphaHb interactions are extensive but suboptimal, explaining why beta-hemoglobin can competitively displace AHSP to form HbA. Remarkably, the Fe(II)-heme group in AHSP bound alphaHb is coordinated by the distal but not the proximal histidine. Importantly, binding to AHSP facilitates the conversion of oxy-alphaHb to a deoxygenated, oxidized [Fe(III)], nonreactive form in which all six coordinate positions are occupied. These observations reveal the molecular mechanisms by which AHSP stabilizes free alphaHb.

  9. Quantitative absorption cytometry for measuring red blood cell hemoglobin mass and volume. (United States)

    Schonbrun, Ethan; Malka, Roy; Di Caprio, Giuseppe; Schaak, Diane; Higgins, John M


    We present an optical system, called the quantitative absorption cytometer (QAC), to measure the volume and hemoglobin mass of red blood cells flowing through a microfluidic channel. In contrast to clinical hematology analyzers, where cells are sphered in order for both volume and hemoglobin to be measured accurately, the QAC measures cells in their normal physiological shape. Human red blood cells are suspended in a refractive index-matching absorbing buffer, driven through a microfluidic channel, and imaged using a transmission light microscope onto a color camera. A red and a blue LED illuminate cells and images at each color are used to independently retrieve cell volume and hemoglobin mass. This system shows good agreement with red blood cell indices retrieved by a clinical hematology analyzer and in fact measures a smaller coefficient of variation of hemoglobin concentration. In addition to cell indices, the QAC returns height and mass maps of each measured cell. These quantitative images are valuable for analyzing the detailed morphology of individual cells as well as statistical outliers found in the data. We also measured red blood cells in hypertonic and hypotonic buffers to quantify the correlation between volume and hemoglobin mass under osmotic stress. Because this method is invariant to cell shape, even extremely nonspherical cells in hypertonic buffers can be measured accurately.

  10. Hemoglobin expression in rat experimental granulation tissue

    Institute of Scientific and Technical Information of China (English)

    Miretta Tommila; Christoffer Stark; Anne Jokilammi; Ville Peltonen; Risto Penttinen; Erika Ekholm


    The general opinion that hemoglobin is only a carrier protein for oxygen and carbon dioxide has been challenged by several recent studies showing hemoglobin expression in other cells than those of the erythroid series, for example, in macrophages. We discovered β-globin expression in rat experimental granulation tissue induced by subcutaneously implanted cellulose sponges. Closer investigation revealed also α-globin expression. The first peak of the biphasic globin expression noticed during granulation tissue formation correlated with the invasion of monocytes/macrophages, whereas the second one seemed to be connected to the appearance of hematopoietic progenitors. Data presented in this study indicate globin expression both in macrophages and in immature erythroid cells as validated by erythroid-specific markers.

  11. Insulin-induced lipid binding to hemoglobin

    Directory of Open Access Journals (Sweden)



    Full Text Available Under hypoglycemic conditions, concomitant hyperinsulinism causes an apparent modification of hemoglobin (Hb which is manifested by its aggregation (Niketi} et al., Clin. Chim. Acta 197 (1991 47. In the present work the causes and mechanisms underlying this Hb modification were studied. Hemoglobin isolated from normal erythrocytes incubated with insulin was analyzed by applying 31P-spectrometry and lipid extraction and analysis. To study the dynamics of the plasma membrane during hyperinsulinism, a fluorescent lipid-analog was applied. In the presence of insulin, phosphatidylserine (PS, phosphatidylethanolamine (PE and cholesterol were found to bind to Hb. Lipid binding resulted in Hb aggregation, a condition that can be reproduced when phospholipids are incubated with Hb in vitro. Using a fluorescent lipid-analog, it was also shown that exposing erythrocytes to supraphysiological concentrations of insulin in vitro resulted in the internalization of lipids. The results presented in this work may have relevance to cases of diabetes mellitus and hypoglycemia.

  12. [Abnormal hemoglobins in Negroid Ecuadorian populations]. (United States)

    Jara, N O; Guevara Espinoza, A; Guderian, R H


    The prevalence of hemoglobinopathies was determined in the black race located in two distinct geographical areas in Ecuador; in the coastal province of Esmeraldas, particularly the Santiago basin (Rio Cayapas and Rio Onzoles) and in the province of Imbabura, particularly in the intermoutain valley, Valle de Chota. A total of 2038 blood samples were analyzed, 1734 in Esmeraldas and 304 in Inbabura, of which 23.2% (473 individuals) were found to be carriers of abnormal hemoglobins, 25.4% (441) in Esmeraldas and 10.5% (32) in Imbabura. The abnormal hemoglobins found in Esmeraldas were Hb AS (19.2%), Hb AC (5.0%), Hb SS (0.6%) and Hb SC (0.5%) while in Imbabura only Hb AS (9.5%) and Hb AC (0.9%) were found. The factors that could influence the difference in prevalence found in the two geographical areas are discussed.

  13. A combined approach for β-thalassemia based on gene therapy-mediated adult hemoglobin (HbA) production and fetal hemoglobin (HbF) induction. (United States)

    Zuccato, Cristina; Breda, Laura; Salvatori, Francesca; Breveglieri, Giulia; Gardenghi, Sara; Bianchi, Nicoletta; Brognara, Eleonora; Lampronti, Ilaria; Borgatti, Monica; Rivella, Stefano; Gambari, Roberto


    Gene therapy might fall short in achieving a complete reversion of the β-thalassemic phenotype due to current limitations in vector design and myeloablative regimen. Following gene transfer, all or a large proportion of erythroid cells might express suboptimal levels of β-globin, impairing the therapeutic potential of the treatment. Our aim was to evaluate whether, in absence of complete reversion of the β-globin phenotype upon gene transfer, it is possible to use fetal hemoglobin induction to eliminate the residual α-globin aggregates and achieve normal levels of hemoglobin. Transgenic K562 cell lines and erythroid precursor cells from β(0)39-thalassemia patients were employed. Gene therapy was performed with the lentiviral vector T9W. Induction of fetal hemoglobin was obtained using mithramycin. Levels of mRNA and hemoglobins were determined by qRT-PCR and HPLC. First, we analyzed the effect of mithramycin on K562 transgenic cell lines harboring different copies of a lentiviral vector carrying the human β-globin gene, showing that γ-globin mRNA expression and HbF production can be induced in the presence of high levels of β-globin gene expression and HbA accumulation. We then treated erythroid progenitor cells from β-thalassemic patients with T9W, which expresses the human β-globin gene and mithramycin separately or in combination. When transduction with our lentiviral vector is insufficient to completely eliminate the unpaired α-globin chains, combination of β-globin gene transfer therapy together with fetal hemoglobin induction might be very efficacious to remove the excess of α-globin proteins in thalassemic erythroid progenitor cells.

  14. Interaction of recombinant octameric hemoglobin with endothelial cells. (United States)

    Gaucher, Caroline; Domingues-Hamdi, Élisa; Prin-Mathieu, Christine; Menu, Patrick; Baudin-Creuza, Véronique


    Hemoglobin-based oxygen carriers (HBOCs) may generate oxidative stress, vasoconstriction and inflammation. To reduce these undesirable vasoactive properties, we increased hemoglobin (Hb) molecular size by genetic engineering with octameric Hb, recombinant (r) HbβG83C. We investigate the potential side effects of rHbβG83C on endothelial cells. The rHbβG83C has no impact on cell viability, and induces a huge repression of endothelial nitric oxide synthase gene transcription, a marker of vasomotion. No induction of Intermolecular-Adhesion Molecule 1 and E-selectin (inflammatory markers) transcription was seen. In the presence of rHbβG83C, the transcription of heme oxygenase-1 (oxidative stress marker) is weakly increased compared to the two other HBOCs (references) or Voluven (control). This genetically engineered octameric Hb, based on a human Hb βG83C mutant, leads to little impact at the level of endothelial cell inflammatory response and thus appears as an interesting molecule for HBOC development.

  15. Optical mammography: bilateral breast symmetry in hemoglobin saturation maps (United States)

    Anderson, Pamela G.; Sassaroli, Angelo; Kainerstorfer, Jana M.; Krishnamurthy, Nishanth; Kalli, Sirishma; Makim, Shital S.; Graham, Roger A.; Fantini, Sergio


    We present a study of the bilateral symmetry of human breast hemoglobin saturation maps measured with a broadband optical mammography instrument. We have imaged 21 patients with unilateral breast cancer, 32 patients with unilateral benign lesions, and 27 healthy patients. An image registration process was applied to the bilateral hemoglobin saturation (SO2) images by assigning each pixel to the low, middle, or high range of SO2 values, where the thresholds for the categories were the 15th and 85th percentiles of the individual saturation range. The Dice coefficient, which is a measure of similarity, was calculated for each patient's pair of right and left breast SO2 images. The invasive cancer patients were found to have an average Dice coefficient value of 0.55±0.07, which was significantly lower than the benign and healthy groups (0.61±0.11 and 0.62±0.12, respectively). Although differences were seen in a group analysis, the healthy patient Dice coefficients spanned a wide range, limiting the diagnostic capabilities of this SO2 symmetry analysis on an individual basis. Our results suggest that for assessing the SO2 contrast of breast lesions, it may be better to select a reference tissue in the ipsilateral rather than the contralateral breast.

  16. Induction of nano pore in Agrobacterial hemoglobin


    Mojtaba Tousheh; Giti Emtiazi; Peyman Derikvand


    Introduction: A variety of oxygen-transport and -binding proteins exist in organisms including bacteria, protozoans, and fungi all have hemoglobin-like proteins. In addition to dealing with transport and sensing of oxygen, they may also deal with NO2, CO2, sulfide compounds, and even O2 scavenging in environments. Also they detoxified chlorinated materials like P450 enzymes and peroxidases and use as a detector of nitrate and hydrogen peroxide. Pore-forming bacterial globins are interested fo...

  17. Facile Interfacial Electron Transfer of Hemoglobin

    Directory of Open Access Journals (Sweden)

    Chunhai Fan


    Full Text Available Abstract: We herein describe a method of depositing hemoglobin (Hb and sulfonated polyaniline (SPAN on GC electrodes that facilitate interfacial protein electron transfer. Well-defined, reproducible, chemically reversible peaks of Hb and SPAN can be obtained in our experiments. We also observed enhanced peroxidase activity of Hb in SPAN films. These results clearly showed that SPAN worked as molecular wires and effectively exchanged electrons between Hb and electrodes.Mediated by Conjugated Polymers

  18. Free heme and sickle hemoglobin polymerization (United States)

    Uzunova, Veselina V.

    This work investigates further the mechanism of one of the most interesting of the protein self-assembly systems---the polymerization of sickle hemoglobin and the role of free heme in it. Polymerization of sickle hemoglobin is the primary event in the pathology of a chronic hemolytic condition called sickle cell anemia with complex pathogenesis, unexplained variability and symptomatic treatment. Auto-oxidation develops in hemoglobin solutions exposed to room temperature and causes release of ferriheme. The composition of such solutions is investigated by mass spectrometry. Heme dimers whose amount corresponds to the initial amounts of heme released from the protein are followed. Differences in the dimer peak height are established for hemoglobin variants A, S and C and depending on the exposure duration. The effects of free heme on polymerization kinetics are studied. Growth rates and two characteristic parameters of nucleation are measured for stored Hb S. After dialysis of polymerizing solutions, no spherulites are detected at moderately high supersaturation and prolonged exposure times. The addition of 0.16-0.26 mM amounts of heme to dialyzed solutions leads to restoration of polymerization. The measured kinetic parameters have higher values compared to the ones before dialysis. The amount of heme in non-dialyzed aged solution is characterized using spectrophotometry. Three methods are used: difference in absorbance of dialyzed and non-dialyzed solutions, characteristic absorbance of heme-albumin complex and absorbance of non-dialyzed solutions with added potassium cyanide. The various approaches suggest the presence of 0.12 to 0.18 mM of free ferriheme in such solutions. Open questions are whether the same amounts of free heme are present in vivo and whether the same mechanism operates intracellulary. If the answer to those questions is positive, then removal of free heme from erythrocytes can influence their readiness to sickle.

  19. Serum ferritin levels in hemoglobin H disease. (United States)

    Galanello, R; Melis, M A; Paglietti, E; Cornacchia, G; de Virgiliis, S; Cao, A


    This study shows that hemoglobin H disease patients aged between 0.5 and 44 years, usually (27 out of 30) have normal serum ferritin levels according to age. This reconfirms that in this disease there are usually normal iron stores. However, in a few patients (3 out of 30) increased levels were found. This may be due to inappropriate iron medication, transfusions or associated idiopathic hereditary hemocromatosis gene.

  20. Induction of nano pore in Agrobacterial hemoglobin

    Directory of Open Access Journals (Sweden)

    Mojtaba Tousheh


    Full Text Available Introduction: A variety of oxygen-transport and -binding proteins exist in organisms including bacteria, protozoans, and fungi all have hemoglobin-like proteins. In addition to dealing with transport and sensing of oxygen, they may also deal with NO2, CO2, sulfide compounds, and even O2 scavenging in environments. Also they detoxified chlorinated materials like P450 enzymes and peroxidases and use as a detector of nitrate and hydrogen peroxide. Pore-forming bacterial globins are interested for filtration. Materials and methods: Although there are data for bacterial toxin as a filter, here we used Agrobacterial hem to induce nano pore in the heme structure using point mutation. Results: Investigations showed that three amino acids leucine 76, alanine 83 and histidine 80 are important for pore formation in Agrobacterium hemoglobin. A point mutation on leucine 76 to glycine, histidine 80 to asparagine and alanine 83 to lysine step by step led to create the nano pore 0.7- 0.8 nm in the globin. Discussion and conclusion: These mutations in bacterial hemoglobin increase the stability when mutation is with it’s at pH7. This mutation decreases the aliphatic index however increase the stability index.

  1. Hemoglobin profiles of siblings of thalassemia patients

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    Muhammad Riza


    Full Text Available Background Thalassemia and hemoglobinopathies are the most common inherited disorders in many areas of the world, including South East Asia. The siblings of thalassemia major is a group of high risk to carry the gene of thalassemia. Determining the carrier is useful for early treatment planning and prevention to the next child. Objective To determine carrier status among siblings of thalassemia patients using a capillary electrophoresis system. Methods A cross-sectional study on the siblings of thalassemia major patients was performed from January 2011 to February 2012 at Dr. Moewardi Hospital. Complete blood counts were performed in the siblings. Subjects with mean corpuscular volume (MCV <80 fl and mean corpuscular hemoglobin (MCH <27 pg were subjected to analize hemoglobin fraction by capillary electrophoresis. Results Of the 26 subjects, there were 12 males and 14 females. The mean age was 9.38 (SD 6.8 years (range 1 to 29 years. From the siblings, 10 were identified as normal, 5 were identified as ß thalassemia carriers and 5 were hemoglobin E (HbE carriers. Six siblings were diagnosed with ß thalassemia/ HbE. Conclusion There are high occurrence of the two common types of thalassemia carriers (ß and HbE in our small group of subjects who had a family history of thalassemia. Most of the siblings of thalassemia had low MCV and MCH. [Paediatr Indones. 2015;55:70-3.].

  2. Fetal hemoglobin in sickle cell anemia. (United States)

    Akinsheye, Idowu; Alsultan, Abdulrahman; Solovieff, Nadia; Ngo, Duyen; Baldwin, Clinton T; Sebastiani, Paola; Chui, David H K; Steinberg, Martin H


    Fetal hemoglobin (HbF) is the major genetic modulator of the hematologic and clinical features of sickle cell disease, an effect mediated by its exclusion from the sickle hemoglobin polymer. Fetal hemoglobin genes are genetically regulated, and the level of HbF and its distribution among sickle erythrocytes is highly variable. Some patients with sickle cell disease have exceptionally high levels of HbF that are associated with the Senegal and Saudi-Indian haplotype of the HBB-like gene cluster; some patients with different haplotypes can have similarly high HbF. In these patients, high HbF is associated with generally milder but not asymptomatic disease. Studying these persons might provide additional insights into HbF gene regulation. HbF appears to benefit some complications of disease more than others. This might be related to the premature destruction of erythrocytes that do not contain HbF, even though the total HbF concentration is high. Recent insights into HbF regulation have spurred new efforts to induce high HbF levels in sickle cell disease beyond those achievable with the current limited repertory of HbF inducers.

  3. Development and validation of a noncontact spectroscopic device for hemoglobin estimation at point-of-care (United States)

    Sarkar, Probir Kumar; Pal, Sanchari; Polley, Nabarun; Aich, Rajarshi; Adhikari, Aniruddha; Halder, Animesh; Chakrabarti, Subhananda; Chakrabarti, Prantar; Pal, Samir Kumar


    Anemia severely and adversely affects human health and socioeconomic development. Measuring hemoglobin with the minimal involvement of human and financial resources has always been challenging. We describe a translational spectroscopic technique for noncontact hemoglobin measurement at low-resource point-of-care settings in human subjects, independent of their skin color, age, and sex, by measuring the optical spectrum of the blood flowing in the vascular bed of the bulbar conjunctiva. We developed software on the LabVIEW platform for automatic data acquisition and interpretation by nonexperts. The device is calibrated by comparing the differential absorbance of light of wavelength 576 and 600 nm with the clinical hemoglobin level of the subject. Our proposed method is consistent with the results obtained using the current gold standard, the automated hematology analyzer. The proposed noncontact optical device for hemoglobin estimation is highly efficient, inexpensive, feasible, and extremely useful in low-resource point-of-care settings. The device output correlates with the different degrees of anemia with absolute and trending accuracy similar to those of widely used invasive methods. Moreover, the device can instantaneously transmit the generated report to a medical expert through e-mail, text messaging, or mobile apps.

  4. Enfermedad por Hemoglobina H: primer caso de la variante de hemoglobina H tipo (-α3.7/ --SEA en Costa Rica. Hemoglobin H Disease: First Case of Hemoglobin H Variant Type (-α<3.7/ --SEA in Costa Rica

    Directory of Open Access Journals (Sweden)

    Walter Cartín-Sánchez


    Full Text Available La enfermedad por Hemoglobina H es la forma más común de talasemia intermedia y posee muchas características que requieren cuidadosa consideración en su manejo clínico. En la mayoría de los casos, la enfermedad por Hemoglobina H resulta de un estado doble heterocigoto producido por una deleción tipo α0 que remueve ambos genes de α-globina en uno de los cromosoma 16 y de una deleción tipo α+ en uno de los genes de α-globina en el otro cromosoma 16, resultando en una condiciσn tipo (--/-α. El exceso de cadenas β de globina precipita y forma una hemoglobina anormal característica; la hemoglobina H (Hb H, un tetrámero de β globina (β4. Los pacientes con hemoglobina H que se encuentran en estado compensado pueden tener niveles de hemoglobina entre 9 y 10 g/dL, sin embargo durante las crisis hemolíticas, que se desarrollan durante o después de infecciones agudas con fiebres altas, la hemoglobina puede llegar a disminuir significativamente y los pacientes pueden desarrollar shock y fallo renal.Aún cuando la esplenectomía eleva la hemoglobina significativamente, no se recomienda porque la mayoría de los pacientes tienen un nivel aceptable de hemoglobina mientras se encuentren compensados. Se presenta el primer caso descrito en Costa Rica de enfermedad por hemoglobina H variante del sudeste asiático (-α3.7/ --SEA.¹Hemoglobin H (Hb H disease is the most common form of thalassemia intermedia and has many features that require careful consideration in its management. In the majority of cases, the disease results from double heterozygosity for α0thalassemia due to deletions that remove both linked αglobin genes on one chromosome 16, and deletional α+ from single α-globin gene deletions on the other chromosome 16 resulting in a (--/-α condition. The excess β globin chain precipitates and forms a characteristic abnormal hemoglobin: hemoglobin H a β globin tetramer (β4. In a steady state, patients with Hb H disease have

  5. 抗胎儿血红蛋白单克隆抗体的制备及特性鉴定%Preparation and Charaterization of Monoclonal Antibodies Against human fetal hemoglobin

    Institute of Scientific and Technical Information of China (English)

    程伟; 刘艳君; 陈远东; 钟梅; 富宁


    目的 制备和鉴定抗胎儿血红蛋白(fetal hemoglobin,HbF)单克隆抗体(mAb),为相关疾病的研究提供支持与工具.方法 用脐带血红细胞裂解物免疫Balb/c小鼠,取其脾细胞与小鼠骨髓瘤细胞(NS-1)融合制备杂交瘤,经筛选和三次克隆化,从制备的腹水中纯化单克隆抗体.用ELISA以及western blot等方法鉴定单克隆抗体的特性(效价、Ig亚类、特异性以及亲和力).结果 筛选到3株可稳定分泌抗HbF单克隆抗体的杂交瘤细胞6A5、5C8、2C8,腹水效价分别为1×10-6、 2×10-6和4×10-6.单抗亚类均为IgG1,抗体亲和力分别为7.8×109、2.2×108和8.6×109.ELISA和western blot结果显示,6A5、5C8、2C8 mAb只与HbF的二聚体特异性结合,与其他类型血红蛋白不发生交叉反应.结论 获得3株能特异性识别HbF的高亲和力mAb,可结合二聚体与单体HbF,为临床检测HbF水平及相关研究提供了有效的工具.

  6. 以人血红蛋白为基础的红细胞代用品修饰工艺的研究%On the Modified Process of Human Hemoglobin Based Blood Substitutes

    Institute of Scientific and Technical Information of China (English)

    李凤娟; 张鸿辉; 王劲峰; 杨成民


    对热敏法纯化的人胎盘血红蛋白进行理化指标及生物学性质进行检测,结果表明纯化血红蛋白的纯度为99%,高铁Hb含量为2.09%,氧结合量为1.19 ml/g,光谱分析表明纯化后空间构象没有发生改变,即保持了生物活性.对纯化血红蛋白进行PLP修饰、GDA聚合工艺形成终产品.对修饰放于聚合步骤之前及之后两种工艺产品的理化指标及生物学性质进行比较,结果表明两种工艺产品的聚合度、高铁血红蛋白含量、氧结合量、P50 光谱分析图都无显著差异,且后修饰可以大大节省PLP用量,降低研究成本,因此可以考虑在研究及生产中采用后修饰工艺.%Purified hemoglobin was modified with pyridoxal 5-phosphate(PLP) and polymerized with glutaric dialdehyde(GDA) to get the products. By comparison of the physical,chemical and biological properties of different procedures for modification before and after polymerization,there is no significant difference in molecular distribution,methemoglobin(MetHb) concentration,oxygen carrier capacity,P50 and spectra. Furthermore,the procedure of modification after polymerization can save PLP greatly and decrease cost greatly. So the procedure of modification after polymerization is a better way in research and production. The addition of GDA could control the increasing of MetHb. By comparison on the physical,chemical and biological properties of different procedures,there is no significant difference in molecular distribution,MetHb concentration,oxygen carrier capacity and spectra between the procedure of adding GDA before PLP and that after PLP. But the P50 of adding GDA before PLP is much lower than that after PLP. So the procedure of adding GDA after PLP is a better way.

  7. A highly luminescent tetramer from a weakly emitting monomer: acid- and redox-controlled multiple complexation by cucurbit[7]uril. (United States)

    Bergamini, Giacomo; Fermi, Andrea; Marchini, Marianna; Locritani, Mirko; Credi, Alberto; Venturi, Margherita; Negri, Fabrizia; Ceroni, Paola; Baroncini, Massimo


    The tetrahedral, shape-persistent molecule 1(4+), containing four pyridylpyridinium units connected through a central carbon atom, exhibits unexpected photophysical properties including a substantially redshifted absorption (2350 cm(-1)) and a very strong fluorescence (Φem = 40 %), compared with the monomer 2(+) (Φem = 0.4 %). Density functional theory calculations on the structure and spectroscopic properties of 1(4+) and 2(+) show that exciton interactions, homoconjugation, and orbital nature account for the observed differences in their photophysical properties. The protonated tetramer binds four cucurbit[7]uril molecules and the host/guest interactions can be controlled by chemical (acid/base) as well as redox stimuli.

  8. Expression and purification of recombinant hemoglobin in Escherichia coli

    DEFF Research Database (Denmark)

    Natarajan, Chandrasekhar; Jiang, Xiaoben; Fago, Angela


    BACKGROUND: Recombinant DNA technologies have played a pivotal role in the elucidation of structure-function relationships in hemoglobin (Hb) and other globin proteins. Here we describe the development of a plasmid expression system to synthesize recombinant Hbs in Escherichia coli, and we describe...... a protocol for expressing Hbs with low intrinsic solubilities. Since the alpha- and beta-chain Hbs of different species span a broad range of solubilities, experimental protocols that have been optimized for expressing recombinant human HbA may often prove unsuitable for the recombinant expression...... of wildtype and mutant Hbs of other species. METHODOLOGY/PRINCIPAL FINDINGS: As a test case for our expression system, we produced recombinant Hbs of the deer mouse (Peromyscus maniculatus), a species that has been the subject of research on mechanisms of Hb adaptation to hypoxia. By experimentally assessing...

  9. Design and structure-activity relationships of potent and selective inhibitors of undecaprenyl pyrophosphate synthase (UPPS): tetramic, tetronic acids and dihydropyridin-2-ones. (United States)

    Peukert, Stefan; Sun, Yingchuan; Zhang, Rui; Hurley, Brian; Sabio, Mike; Shen, Xiaoyu; Gray, Christen; Dzink-Fox, JoAnn; Tao, Jianshi; Cebula, Regina; Wattanasin, Sompong


    Based on a pharmacophore hypothesis substituted tetramic and tetronic acid 3-carboxamides as well as dihydropyridin-2-one-3-carboxamides were investigated as inhibitors of undecaprenyl pyrophosphate synthase (UPPS) for use as novel antimicrobial agents. Synthesis and structure-activity relationship patterns for this class of compounds are discussed. Selectivity data and antibacterial activities for selected compounds are provided.

  10. Mini-hemoglobins from nemertean worms. (United States)

    Vandergon, Thomas L; Riggs, Austen F


    Hemoglobins (Hbs) found in members of the phylum Nemertea are smaller than any other known Hb molecules. These mini-Hbs have been of great interest because of their unique three-dimensional structure and their stable ligand-binding properties. Also of interest is the expression of mini-Hb in neural tissue, body wall muscle tissue, and red blood cells. This chapter outlines methods that may be used to isolate and purify functional mini-Hbs from all three tissue types in nemertean worms.

  11. Relationship of Baseline Hemoglobin Level with Serum Ferritin, Postphlebotomy Hemoglobin Changes, and Phlebotomy Requirements among HFE C282Y Homozygotes

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    Seyed Ali Mousavi


    Full Text Available Objectives. We aimed to examine whether baseline hemoglobin levels in C282Y-homozygous patients are related to the degree of serum ferritin (SF elevation and whether patients with different baseline hemoglobin have different phlebotomy requirements. Methods. A total of 196 patients (124 males and 72 females who had undergone therapeutic phlebotomy and had SF and both pre- and posttreatment hemoglobin values were included in the study. Results. Bivariate correlation analysis suggested that baseline SF explains approximately 6 to 7% of the variation in baseline hemoglobin. The results also showed that males who had higher (≥150 g/L baseline hemoglobin levels had a significantly greater reduction in their posttreatment hemoglobin despite requiring fewer phlebotomies to achieve iron depletion than those who had lower (<150 g/L baseline hemoglobin, regardless of whether baseline SF was below or above 1000 µg/L. There were no significant differences between hemoglobin subgroups regarding baseline and treatment characteristics, except for transferrin saturation between male subgroups with SF above 1000 µg/L. Similar differences were observed when females with higher (≥138 g/L baseline hemoglobin were compared with those with lower (<138 g/L baseline hemoglobin. Conclusion. Dividing C282Y-homozygous patients into just two subgroups according to the degree of baseline SF elevation may obscure important subgroup variations.

  12. Hemoglobin Moabit: alpha 86 (F7) Leu leads to Arg: a new unstable abnormal hemoglobin. (United States)

    Knuth, A; Pribilla, W; Marti, H R; Winterhalter, K H


    A new alpha chain abnormal hemoglobin variant was found in a Turkish patient with a mild Heinz body hemolytic anemia and splenomegaly. The substitution alpha 86 Leu leads to Arg, which is next to the heme binding proximal histidine, is responsible for a marked instability of the molecule. The oxygen affinity of the erythrocytes was found to be slightly decreased.

  13. Stability of Blood Samples for Hemoglobin Electrophoresis

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    Yadira Valdés Fraser


    Full Text Available Background: the National Medical Genetics Center has conducted the prenatal screening for hemoglobinopathies in the province of Artemisa and the quality control of this program nationwide; reliability of the results is determined by the quality of the samples used. Objective: to describe the stability of whole blood samples using EDTAK2 and heparin as anticoagulants. Methods: a descriptive study of 100 samples of whole blood from pregnant women and their husbands was conducted at the National Medical Genetics Center. Hemoglobin electrophoresis with Hydrasis technology was performed using 10 % EDTAK2, 2.2 % and 5 % heparin, temperature at 4-8 0C and shelf-life of 7.15 and 30 days. Results: samples with EDTAK2 showed stability for a month with accuracy and repeatability in the electrophoresis runs. By using 5 % and 2.2 % heparin, problems were found in all periods analyzed. Conclusions: 10 % EDTAK2 anticoagulant is appropriate to ensure the reliability of the results in the screening for hemoglobinopathies. The results obtained in this study can be applied in all clinical, hematological and hemoglobin electrophoresis laboratories.

  14. A review of variant hemoglobins interfering with hemoglobin A1c measurement. (United States)

    Little, Randie R; Roberts, William L


    Hemoglobin A1c (HbA1c) is used routinely to monitor long-term glycemic control in people with diabetes mellitus, as HbA1c is related directly to risks for diabetic complications. The accuracy of HbA1c methods can be affected adversely by the presence of hemoglobin (Hb) variants or elevated levels of fetal hemoglobin (HbF). The effect of each variant or elevated HbF must be examined with each specific method. The most common Hb variants worldwide are HbS, HbE, HbC, and HbD. All of these Hb variants have single amino acid substitutions in the Hb beta chain. HbF is the major hemoglobin during intrauterine life; by the end of the first year, HbF falls to values close to adult levels of approximately 1%. However, elevated HbF levels can occur in certain pathologic conditions or with hereditary persistence of fetal hemoglobin. In a series of publications over the past several years, the effects of these four most common Hb variants and elevated HbF have been described. There are clinically significant interferences with some methods for each of these variants. A summary is given showing which methods are affected by the presence of the heterozygous variants S, E, C, and D and elevated HbF. Methods are divided by type (immunoassay, ion-exchange high-performance liquid chromatography, boronate affinity, other) with an indication of whether the result is artificially increased or decreased by the presence of a Hb variant. Laboratorians should be aware of the limitations of their method with respect to these interferences.

  15. Properties of Hemoglobin Decolorized with a Histidine-Specific Protease. (United States)

    Shi, Jing; de Roos, Andre; Schouten, Olaf; Zheng, Chaoya; Vink, Collin; Vonk, Brenda; Kliphuis, Annette; Schaap, Albert; Edens, Luppo


    This study investigated the application of Aspergilloglutamic peptidase (AGP) on porcine hemoglobin decolorization. AGP from fungus Aspergillus niger is identified to possess a high preference towards the histidine residues. As histidine residues in hemoglobin are known to coordinate the heme group within the globin molecule, we therefore hypothesized that incubating hemoglobin with a histidine-specific protease would efficiently separate the non-heme peptides from the heme-enriched peptides with a minimum degree of hydrolysis. AGP-decolored porcine hemoglobin hydrolysates were assessed on their functional (for example, color, emulsification, foaming, and water binding) and sensory properties. The results were compared with commercially available blood-derived proteins (subtilisin-decolored hemoglobin hydrolysates and plasma protein). It was observed that AGP is able to effectively decolor hemoglobin. The degree of hydrolysis (DH) increased less than 3% using AGP to achieve 90% color reduction of hemoglobin, whereas a DH increase of more than 20% is needed using subtilisin. The AGP-decolored hemoglobin hydrolysates (AGP-Hb) possess good emulsification, foaming, and water binding properties, which are better or comparable with the plasma protein, and much better than the subtilisin-decolored hemoglobin hydrolysates (subtilisin-Hb). The model canned meat with addition of AGP-Hb showed the highest value in hardness, springiness, and chewiness from the texture analysis. Furthermore, the canned meat with AGP-Hb was found to have a better sensory profile than the ones with addition of subtilisin-Hb and plasma protein.

  16. Hemoglobin screening: response of a Brazilian community to optional programs

    Directory of Open Access Journals (Sweden)

    Antonio Sérgio Ramalho


    Full Text Available The efficiency and the viability of three hemoglobin screening programs were investigated. They were offered on a voluntary basis to a Brazilian population and started with the analysis of blood donors, pregnant women and students. The hemoglobin screening was done through optional exams which included electrophoresis of hemoglobin and complementary hematological tests. A total of 13,670 people were tested over a period of 39 months and a total of 644 individuals with hereditary hemoglobin disorders were detected - 4.7% of the samples examined. The programs showed satisfactory indicators of viability and efficiency, expressed by the significative proportion of exams performed among the probands and their relatives.

  17. Reactivation of fetal hemoglobin in thalassemia and sickle cell disease

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    Sandro Eridani


    Full Text Available Considerable attention has been recently devoted to mechanisms involved in the perinatal hemoglobin switch, as it was long ago established that the survival of fetal hemoglobin (HbF production in significant amount can reduce the severity of the clinical course in severe disorders like β-thalassemia and sickle cell disease (SCD. For instance, when β-thalassemia is associated with hereditary persistence of fetal hemoglobin (HPFH the disease takes a mild course, labeled as thalassemia intermedia. The same clinical amelioration occurs for the association between HPFH and SCD. As for the mechanism of this effect, some information has been obtained from the study of natural mutations at the human β-globin locus in patients with increased HbF, like the Corfu thalassemia mutations. Important evidence came from the discovery that drugs capable of improving the clinical picture of SCD, like decitabine ad hydroxycarbamide, are acting through the reactivation, to some extent, of HbF synthesis. The study of the mechanism of action of these compounds was followed by the identification of some genetic determinants, which promote this event. In particular, among a few genetic factors involved in this process, the most relevant appears the BCL11A gene, which is now credited to be able to silence γ-globin genes in the perinatal period by interaction with several erythroid-specific transcription factors and is actually considered as a barrier to HbF reactivation by known HbF inducing agents. Epigenetics is also a player in the process, mainly through DNA demethylation. This is certified by the recent demonstration that hypomethylating agents such as 5-azacytidine and decitabine, the first compounds used for HbF induction by pharmacology, act as irreversible inhibitors of demethyltransferase enzymes. Great interest has also been raised by the finding that several micro-RNAs, which act as negative regulators of gene expression, have been implicated in the

  18. Using photoluminescent gold nanodots to detect hemoglobin in diluted blood samples. (United States)

    Chen, Li-Yi; Huang, Chih-Ching; Chen, Wei-Yu; Lin, Han-Jia; Chang, Huan-Tsung


    In this study we used photoluminescent 11-mercaptoundecanoic acid-bound gold nanodots (11-MUA-Au NDs) to detect hemoglobin through photoluminescence (PL) quenching. The mechanism of quenching, which occurred through redox reactions between the 11-MUA-Au NDs and the Fe(II) atoms of hemin units, was supported by an increase in the signals (G 2.0 and 5.9) of high-spin state Fe(III) ions. The Stern-Volmer quenching constants (Ksv) for hemin, cytochrome c, hemoglobin, and myoglobin were 5.6×10(7), 1.7×10(7), 1.6×10(7), and 6.2×10(6)M(-1), respectively, in good agreement with the order of their reduction potentials. When excited at 375nm, the PL intensity of the 11-MUA-Au NDs at 520nm decreased upon increasing the concentration of hemoglobin from 1.0 to 10nM (R(2)=0.9913). This approach using bovine serum albumin blocked 11-MUA-Au NDs provided a limit of detection for hemoglobin (at a signal-to-noise ratio of 3) of 0.5nM in biological buffer, with great selectivity over other non-heme-containing proteins, including human serum albumin, β-casein, and carbonic anhydrase. We validated the practicality of this approach through the determination of the concentrations (1.85-2.46mM) of hemoglobin in diluted (10(6)-fold) human blood samples based on PL quenching of Au NDs. This simple, sensitive, and selective approach holds great potential for the diagnosis of several diseases, including anemia, erythrocytosis, and thalassemias. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Partial primary structure of human pregnancy zone protein: extensive sequence homology with human alpha 2-macroglobulin

    DEFF Research Database (Denmark)

    Sottrup-Jensen, Lars; Folkersen, J; Kristensen, Torsten;


    Human pregnancy zone protein (PZP) is a major pregnancy-associated protein. Its quaternary structure (two covalently bound 180-kDa subunits, which are further non-covalently assembled into a tetramer of 720 kDa) is similar to that of human alpha 2-macroglobulin (alpha 2M). Here we show, from the ...

  20. Combinatorics of giant hexagonal bilayer hemoglobins. (United States)

    Hanin, L G; Vinogradov, S N


    The paper discusses combinatorial and probabilistic models allowing to characterize various aspects of spacial symmetry and structural heterogeneity of the giant hexagonal bilayer hemoglobins (HBL Hb). Linker-dodecamer configurations of HBL are described for two and four linker types (occurring in the two most studied HBL Hb of Arenicola and Lumbricus, respectively), and the most probable configurations are found. It is shown that, for HBL with marked dodecamers, the number of 'normal-marked' pairs of dodecamers in homological position follows a binomial distribution. The group of symmetries of the dodecamer substructure of HBL is identified with the dihedral group D6. Under natural symmetry assumptions, the total dipole moment of the dodecamer substructure of HBL is shown to be zero. Biological implications of the mathematical findings are discussed.

  1. Conformational changes in hemoglobin triggered by changing the iron charge

    Energy Technology Data Exchange (ETDEWEB)

    Croci, S., E-mail: [University of Parma, Departments of Public Health, INBB Parma (Italy); Achterhold, K. [Physik-Department E17 (Germany); Ortalli, I. [University of Parma, Departments of Public Health, INBB Parma (Italy); Parak, F. G. [Physik-Department E17 (Germany)


    In this work the hemoglobin conformational changes induced by changing the iron charge have been studied and compared with Myoglobin. Moessbauer spectroscopy was used to follow the change of the iron conformation. In order to compare the conformational relaxation of hemoglobin and myoglobin, and to study a possible influence of the quaternary structure, an intermediate metastable state of hemoglobin has been created by low temperature X-ray irradiation of methemoglobin. The irradiation reduces the Fe(III) of the heme groups to Fe(II) Low Spin, where the water is still bound on the sixth coordination. Heating cycles performed at temperatures from 140 K to 200 K allow the molecules to overcome an activation energy barrier and to relax into a stable conformation such as deoxy-hemoglobin or carboxy-hemoglobin, if CO is present. Slightly different structures (conformational substates) reveal themselves as a distribution of energy barriers ({Delta}G). The distribution of the activation energy, for the decay of the Fe(II) Low Spin intermediate, has been fitted with a Gaussian. For comparison, published myoglobin data were re-analysed in the same way. The average energy value at characteristic temperature is very similar in case of myoglobin and hemoglobin. The larger Gaussian energy distribution for myoglobin with respect to hemoglobin shows that more conformational substates are available. This may be caused by a larger area exposed to water. In hemoglobin, part of the surface of the chains is not water accessible due to the quaternary structure.

  2. The influence of socioeconomic status on the hemoglobin level and ...

    African Journals Online (AJOL)

    and hemoglobin concentration were observed from social class 1 to 4; this was statistically significant in controls ... Key words: Hemoglobin level, sickle cell anemia, socioeconomic class ..... This study was designed to determine the relationship .... sickle cell anaemia: studies of serum gonadotropin concentration, height,.

  3. 21 CFR 864.7455 - Fetal hemoglobin assay. (United States)


    ... hemoglobin present. The assay may be used to detect fetal red cells in the maternal circulation or to detect... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Fetal hemoglobin assay. 864.7455 Section 864.7455...) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Kits and Packages § 864.7455 Fetal...

  4. Receptor targeting of hemoglobin mediated by the haptoglobins

    DEFF Research Database (Denmark)

    Nielsen, Marianne Jensby; Moestrup, Søren Kragh


    Haptoglobin, the haptoglobin-hemoglobin receptor CD163, and the heme oxygenase-1 are proteins with a well-established function in the clearance and metabolism of "free" hemoglobin released during intravascular hemolysis. This scavenging system counteracts the potentially harmful oxidative and NO-...

  5. Symbiotic and nonsymbiotic hemoglobin genes of Casuarina glauca

    DEFF Research Database (Denmark)

    Jacobsen-Lyon, K; Jensen, Erik Østergaard; Jørgensen, Jan-Elo


    Casuarina glauca has a gene encoding hemoglobin (cashb-nonsym). This gene is expressed in a number of plant tissues. Casuarina also has a second family of hemoglobin genes (cashb-sym) expressed at a high level in the nodules that Casuarina forms in a nitrogen-fixing symbiosis with the actinomycete...

  6. Structure and function of tetrameric hemoglobins and their mutants at a molecular and cellular level.


    Balsamo, Anna


    The present Ph.D. thesis has focused on tetrameric hemoglobins (Hbs), both recombinant and natural, both from human origin and Antarctic fish, using a multidisciplinary approach based on spectroscopic, crystallographic and computational techniques. In particular the main scope of the research has been the elucidation of two still unsolved problems in the chemistry of tetrameric Hbs: 1) the role of the bis-histidyl heme coordination in the Hb function and oxidation process and 2) the role of t...

  7. Interference of the Hope Hemoglobin With Hemoglobin A1c Results. (United States)

    Chakraborty, Sutirtha; Chanda, Dalia; Gain, Mithun; Krishnan, Prasad


    Hemoglobin A1c (HbA1c) is now considered to be the marker of choice in diagnosis and management of diabetes mellitus, based on the results of certain landmark clinical trials. Herein, we report the case of a 52-year-old ethnic Southeast Asian Indian man with impaired glucose tolerance whose glycated hemoglobin (ie, HbA1c) levels, as measured via Bio-Rad D10 high-performance liquid chromatography (HPLC) and Roche Tina-quant immunoassay were 47.8% and 44.0%, respectively. No variant hemoglobin (Hb) peak was observed via the D10 chromatogram. We assayed the patient specimen on the Sebia MINICAP capillary electrophoresis platform; the HbA1c level was 6.8%, with a large variant Hb peak of 42.0%. This finding suggested the possible presence of the heterozygous Hb Hope, which can result in spuriously elevated HbA1c results on HPLC and turbidimetric immunoassays. Although the capillary electrophoresis system was able to identify the variant, the A1c results should not be considered accurate due to overlapping of the variant and adult Hb peaks on the electrophoretogram reading. Hb Hope is usually clinically silent but can present such analytical challenges. Through this case study, we critically discuss the limitations of various HbA1c assay methods, highlighting the fact that laboratory professionals need to be aware of occurrences of Hb Hope, to help ensure patient safety.

  8. Insights into Hemoglobin Assembly through in Vivo Mutagenesis of α-Hemoglobin Stabilizing Protein* (United States)

    Khandros, Eugene; Mollan, Todd L.; Yu, Xiang; Wang, Xiaomei; Yao, Yu; D'Souza, Janine; Gell, David A.; Olson, John S.; Weiss, Mitchell J.


    α-Hemoglobin stabilizing protein (AHSP) is believed to facilitate adult Hemoglobin A assembly and protect against toxic free α-globin subunits. Recombinant AHSP binds multiple forms of free α-globin to stabilize their structures and inhibit precipitation. However, AHSP also stimulates autooxidation of αO2 subunit and its rapid conversion to a partially unfolded bishistidyl hemichrome structure. To investigate these biochemical properties, we altered the evolutionarily conserved AHSP proline 30 in recombinantly expressed proteins and introduced identical mutations into the endogenous murine Ahsp gene. In vitro, the P30W AHSP variant bound oxygenated α chains with 30-fold increased affinity. Both P30W and P30A mutant proteins also caused decreased rates of αO2 autooxidation as compared with wild-type AHSP. Despite these abnormalities, mice harboring P30A or P30W Ahsp mutations exhibited no detectable defects in erythropoiesis at steady state or during induced stresses. Further biochemical studies revealed that the AHSP P30A and P30W substitutions had minimal effects on AHSP interactions with ferric α subunits. Together, our findings indicate that the ability of AHSP to stabilize nascent α chain folding intermediates prior to hemin reduction and incorporation into adult Hemoglobin A is physiologically more important than AHSP interactions with ferrous αO2 subunits. PMID:22287545

  9. Insights into hemoglobin assembly through in vivo mutagenesis of α-hemoglobin stabilizing protein. (United States)

    Khandros, Eugene; Mollan, Todd L; Yu, Xiang; Wang, Xiaomei; Yao, Yu; D'Souza, Janine; Gell, David A; Olson, John S; Weiss, Mitchell J


    α-Hemoglobin stabilizing protein (AHSP) is believed to facilitate adult Hemoglobin A assembly and protect against toxic free α-globin subunits. Recombinant AHSP binds multiple forms of free α-globin to stabilize their structures and inhibit precipitation. However, AHSP also stimulates autooxidation of αO(2) subunit and its rapid conversion to a partially unfolded bishistidyl hemichrome structure. To investigate these biochemical properties, we altered the evolutionarily conserved AHSP proline 30 in recombinantly expressed proteins and introduced identical mutations into the endogenous murine Ahsp gene. In vitro, the P30W AHSP variant bound oxygenated α chains with 30-fold increased affinity. Both P30W and P30A mutant proteins also caused decreased rates of αO(2) autooxidation as compared with wild-type AHSP. Despite these abnormalities, mice harboring P30A or P30W Ahsp mutations exhibited no detectable defects in erythropoiesis at steady state or during induced stresses. Further biochemical studies revealed that the AHSP P30A and P30W substitutions had minimal effects on AHSP interactions with ferric α subunits. Together, our findings indicate that the ability of AHSP to stabilize nascent α chain folding intermediates prior to hemin reduction and incorporation into adult Hemoglobin A is physiologically more important than AHSP interactions with ferrous αO(2) subunits.

  10. Partial Restoration of Normal Functional Properties in Carboxypeptidase A-Digested Hemoglobin (United States)

    Bonaventura, Joseph; Bonaventura, Celia; Giardina, Bruno; Antonini, Eraldo; Brunori, Maurizio; Wyman, Jeffries


    In the absence of organic phosphates human hemoglobin A digested with carboxypeptidase A (des His, Tyr β) has high ligand affinity, a greatly reduced Bohr effect, and no heme-heme interaction. Under these conditions, it shows the simple, homogeneous ligand-binding kinetics characteristic of noncooperative heme proteins in which the high combination velocity for both O2 and CO accounts, to a larger extent, for the increased affinity for both these ligands. Addition of inositol hexaphosphate dramatically alters the functional properties of this digested hemoglobin. The Bohr effect is greatly increased, and at neutral pH the protein shows significant, though still reduced, heme-heme interaction, together with a 5-fold decrease in affinity. In the presence of saturating amounts of the organic phosphate, the value of n is pH dependent, dropping from 1.9 at pH 5.8 to 1.3 at pH 8.6. After inositol hexaphosphate addition, the combination of the deoxy form of the digested hemoglobin with CO is 10-times slower than that observed in the absence of the inorganic phosphate; also the combination with CO after flash photolysis is biphasic and is similar, in many respects, to that observed for unmodified hemoglobin. Besides these functional changes, addition of inositol hexaphosphate to the modified deoxyhemoglobin results in an increase in the extinction coefficient at 430 nm similar to that observed on mixing the isolated α and β chains of normal hemoglobin. The results are consistent with the idea that inositol hexaphosphate shifts an equilibrium between high- and low-affinity forms of the protein. PMID:4506087

  11. Fabrication of Colloidal Laves Phases via Hard Tetramers and Hard Spheres: Bulk Phase Diagram and Sedimentation Behavior. (United States)

    Avvisati, Guido; Dasgupta, Tonnishtha; Dijkstra, Marjolein


    Colloidal photonic crystals display peculiar optical properties that make them particularly suitable for application in different fields. However, the low packing fraction of the targeted structures usually poses a real challenge in the fabrication stage. Here, we propose a route to colloidal photonic crystals via a binary mixture of hard tetramers and hard spheres. By combining theory and computer simulations, we calculate the phase diagram as well as the stacking diagram of the mixture and show that a colloidal analogue of the MgCu2 Laves phase-which can serve as a precursor of a photonic band-gap structure-is a thermodynamically stable phase in a large region of the phase diagram. Our findings show a relatively large coexistence region between the fluid and the Laves phase, which is potentially accessible by experiments. Furthermore, we determine the sedimentation behavior of the suggested mixture, by identifying several stacking sequences in the sediment. Our work uncovers a self-assembly path toward a photonic structure with a band gap in the visible region.

  12. Fabrication of Colloidal Laves Phases via Hard Tetramers and Hard Spheres: Bulk Phase Diagram and Sedimentation Behavior (United States)


    Colloidal photonic crystals display peculiar optical properties that make them particularly suitable for application in different fields. However, the low packing fraction of the targeted structures usually poses a real challenge in the fabrication stage. Here, we propose a route to colloidal photonic crystals via a binary mixture of hard tetramers and hard spheres. By combining theory and computer simulations, we calculate the phase diagram as well as the stacking diagram of the mixture and show that a colloidal analogue of the MgCu2 Laves phase—which can serve as a precursor of a photonic band-gap structure—is a thermodynamically stable phase in a large region of the phase diagram. Our findings show a relatively large coexistence region between the fluid and the Laves phase, which is potentially accessible by experiments. Furthermore, we determine the sedimentation behavior of the suggested mixture, by identifying several stacking sequences in the sediment. Our work uncovers a self-assembly path toward a photonic structure with a band gap in the visible region. PMID:28787126

  13. 3D Printing of Aniline Tetramer-Grafted-Polyethylenimine and Pluronic F127 Composites for Electroactive Scaffolds. (United States)

    Dong, Shi-Lei; Han, Lu; Du, Cai-Xia; Wang, Xiao-Yu; Li, Lu-Hai; Wei, Yen


    Electroactive hydrogel scaffolds are fabricated by the 3D-printing technique using composites of 30% Pluronic F127 and aniline tetramer-grafted-polyethylenimine (AT-PEI) copolymers with various contents from 2.5% to 10%. The synthesized AT-PEI copolymers can self-assemble into nanoparticles with the diameter of ≈50 nm and display excellent electroactivity due to AT conjugation. The copolymers are then homogeneously distributed into 30% Pluronic F127 solution by virtue of the thermosensitivity of F127, denoted as F/AT-PEI composites. Macroscopic photographs of latticed scaffolds elucidate their excellent printability of F/AT-PEI hydrogels for the 3D-printing technique. The conductivities of the printed F/AT-PEI scaffolds are all higher than 2.0 × 10(-3) S cm(-1) , which are significantly improved compared with that of F127 scaffold with only 0.94 × 10(-3) S cm(-1) . Thus, the F/AT-PEI scaffolds can be considered as candidates for application in electrical stimulation of tissue regeneration such as repair of muscle and cardiac nerve tissue. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Effect of Multiple Mutations in the Hemoglobin- and Hemoglobin-Haptoglobin-Binding Proteins, HgpA, HgpB, and HgpC, of Haemophilus influenzae Type b


    Morton, Daniel J; Whitby, Paul W.; Jin, Hongfan; Ren, Zhen; Stull, Terrence L.


    Haemophilus influenzae requires heme for growth and can utilize hemoglobin and hemoglobin-haptoglobin as heme sources. We previously identified two hemoglobin- and hemoglobin-haptoglobin-binding proteins, HgpA and HgpB, in H. influenzae HI689. Insertional mutation of hgpA and hgpB, either singly or together, did not abrogate the ability to utilize or bind either hemoglobin or the hemoglobin-haptoglobin complex. A hemoglobin affinity purification method was used to isolate a protein of approxi...

  15. Genomic organization and evolution of the Atlantic salmon hemoglobin repertoire

    Directory of Open Access Journals (Sweden)

    Phillips Ruth B


    Full Text Available Abstract Background The genomes of salmonids are considered pseudo-tetraploid undergoing reversion to a stable diploid state. Given the genome duplication and extensive biological data available for salmonids, they are excellent model organisms for studying comparative genomics, evolutionary processes, fates of duplicated genes and the genetic and physiological processes associated with complex behavioral phenotypes. The evolution of the tetrapod hemoglobin genes is well studied; however, little is known about the genomic organization and evolution of teleost hemoglobin genes, particularly those of salmonids. The Atlantic salmon serves as a representative salmonid species for genomics studies. Given the well documented role of hemoglobin in adaptation to varied environmental conditions as well as its use as a model protein for evolutionary analyses, an understanding of the genomic structure and organization of the Atlantic salmon α and β hemoglobin genes is of great interest. Results We identified four bacterial artificial chromosomes (BACs comprising two hemoglobin gene clusters spanning the entire α and β hemoglobin gene repertoire of the Atlantic salmon genome. Their chromosomal locations were established using fluorescence in situ hybridization (FISH analysis and linkage mapping, demonstrating that the two clusters are located on separate chromosomes. The BACs were sequenced and assembled into scaffolds, which were annotated for putatively functional and pseudogenized hemoglobin-like genes. This revealed that the tail-to-tail organization and alternating pattern of the α and β hemoglobin genes are well conserved in both clusters, as well as that the Atlantic salmon genome houses substantially more hemoglobin genes, including non-Bohr β globin genes, than the genomes of other teleosts that have been sequenced. Conclusions We suggest that the most parsimonious evolutionary path leading to the present organization of the Atlantic salmon

  16. Oxygen binding by alpha(Fe2+)2beta(Ni2+)2 hemoglobin crystals. (United States)

    Bruno, S; Bettati, S; Manfredini, M; Mozzarelli, A; Bolognesi, M; Deriu, D; Rosano, C; Tsuneshige, A; Yonetani, T; Henry, E R


    Oxygen binding by hemoglobin fixed in the T state either by crystallization or by encapsulation in silica gels is apparently noncooperative. However, cooperativity might be masked by different oxygen affinities of alpha and beta subunits. Metal hybrid hemoglobins, where the noniron metal does not bind oxygen, provide the opportunity to determine the oxygen affinities of alpha and beta hemes separately. Previous studies have characterized the oxygen binding by alpha(Ni2+)2beta(Fe2+)2 crystals. Here, we have determined the three-dimensional (3D) structure and oxygen binding of alpha(Fe2+)2beta(Ni2+)2 crystals grown from polyethylene glycol solutions. Polarized absorption spectra were recorded at different oxygen pressures with light polarized parallel either to the b or c crystal axis by single crystal microspectrophotometry. The oxygen pressures at 50% saturation (p50s) are 95 +/- 3 and 87 +/- 4 Torr along the b and c crystal axes, respectively, and the corresponding Hill coefficients are 0.96 +/- 0.06 and 0.90 +/- 0.03. Analysis of the binding curves, taking into account the different projections of the alpha hemes along the optical directions, indicates that the oxygen affinity of alpha1 hemes is 1.3-fold lower than alpha2 hemes. Inspection of the 3D structure suggests that this inequivalence may arise from packing interactions of the Hb tetramer within the monoclinic crystal lattice. A similar inequivalence was found for the beta subunits of alpha(Ni2+)2beta(Fe2+)2 crystals. The average oxygen affinity of the alpha subunits (p50 = 91 Torr) is about 1.2-fold higher than the beta subunits (p50 = 110 Torr). In the absence of cooperativity, this heterogeneity yields an oxygen binding curve of Hb A with a Hill coefficient of 0.999. Since the binding curves of Hb A crystals exhibit a Hill coefficient very close to unity, these findings indicate that oxygen binding by T-state hemoglobin is noncooperative, in keeping with the Monod, Wyman, and Changeux model.

  17. One-pot synthesis of cyclic aldol tetramer and,β-unsaturated aldol from linear aldehydes using quaternary ammonium combined with sodium hydroxide as catalysts

    Institute of Scientific and Technical Information of China (English)

    许海峰; 钟宏; 王帅; 李方旭


    One-pot synthesis of cyclic aldol tetramer anda,β-unsaturated aldol from C3−C8 linear aldehydes using phase-transfer catalyst (PTC), quaternary ammonium, combined with sodium hydroxide as catalysts was investigated. Butanal was subjected for detail investigations to study the effect of parameters. It was found that the selectivity of cyclic aldol tetramer depends greatly on the operating conditions of the reaction, especially the PTC/butanal molar ratio. The average selectivity of 2-hydroxy-6-propyl-l, 3, 5-triethyl-3-cyclohexene-1-carboxaldehyde (HPTECHCA) was 54.41% using tetrabutylammonium chloride combined with 14% (mass fraction) NaOH as catalysts at 60 °C for 2 h with a PTC-to-butanal molar ratio of 0.09:1. Pentanal was more likely to generate cyclic aldol tetramer compared with other aldehydes under the optimum experimental conditions. Recovery of the PTC through water washing followed by adding enough sodium hydroxide from the washings was also demonstrated.

  18. Production of NY-ESO-1 peptide/DRB1*08:03 tetramers and ex vivo detection of CD4 T-cell responses in vaccinated cancer patients. (United States)

    Mizote, Yu; Uenaka, Akiko; Isobe, Midori; Wada, Hisashi; Kakimi, Kazuhiro; Saika, Takashi; Kita, Shoichi; Koide, Yukari; Oka, Mikio; Nakayama, Eiichi


    We established CD4 T-cell clones, Mz-1B7, and Ue-21, which recognized the NY-ESO-1 121-138 peptide from peripheral blood mononuclear cells (PBMCs) of an esophageal cancer patient, E-2, immunized with an NY-ESO-1 protein and determined the NY-ESO-1 minimal epitopes. Minimal peptides recognized by Mz-1B7 and Ue-21 were NY-ESO-1 125-134 and 124-134, respectively, both in restriction to DRB1*08:03. Using a longer peptide, 122-135, and five other related peptides, including either of the minimal epitopes recognized by the CD4 T-cell clones, we investigated the free peptide/DR recognition on autologous EBV-B cells as APC and peptide/DR tetramer binding. The results showed a discrepancy between them. The tetramers with several peptides recognized by either Mz-1B7 or the Ue-21 CD4 T-cell clone did not bind to the respective clone. On the other hand, unexpected binding of the tetramer with the peptide not recognized by CD4 T-cells was observed. The clone Mz-1B7 did not recognize the free peptide 122-135 on APC, but the peptide 122-135/DRB1*08:03 tetramer bound to the TCR on those cells. The failure of tetramer production and the unexpected tetramer binding could be due to a subtly modified structure of the peptide/DR tetramer from the structure of the free peptide/DR molecule. We also demonstrated that the NY-ESO-1 123-135/DRB1*08:03 tetramer detected ex vivo CD4 T-cell responses in PBMCs from patients after NY-ESO-1 vaccination in immunomonitoring. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. In-depth comparative characterization of hemoglobin glycation in normal and diabetic bloods by LC-MSMS. (United States)

    Wang, Shih-Hao; Wang, Tzu-Fan; Wu, Chih-Hsing; Chen, Shu-Hui


    The glycation level at β-Val-1 of the hemoglobin β chain in human blood (HbA1c%) is used to diagnose diabetes and other diseases. However, hemoglobin glycation occurs on multiple sites on different isoforms with different kinetics, but its differential profile has not been clearly demonstrated. In this study, hemoglobin was extracted from the blood of normal and diabetic individuals by protein precipitation. Triplicate solutions prepared from each sample were directly analyzed or digested with multiple enzymes and then analyzed by nano-LC/MS via bottom-up approach for side-by-side characterization. Intact hemoglobin analysis indicated a single glucose-dominant glycation, which showed good correlation with the HbA1c% values. Moreover, full sequence (100%) of α/β globin was mapped and seven glycation sites were unambiguously assigned. In addition to β-Val-1, two other major sites at α-Lys-61 and β-Lys-66, which contain the common sequence HGKK, and four minor sites (glycation percentage of the β-globin was twice higher than the α-globin. Using molecular modeling, the 3D structure of the consensus sequence (HGKK) was shown to contain a phosphate triangle cavity, which helps to catalyze the glycation reaction. For the first time, hemoglobin glycation in normal and diabetic bloods was comparatively characterized in-depth with 100% sequence coverage. The results provide insight about the HbA1c parameter and help define the new and old markers.

  20. Preparation of porcine hemoglobin microcapsules of chitosan-sodium alginate

    Institute of Scientific and Technical Information of China (English)

    LI Jun; ZHANG Jijuan; ZHAO Xinjuan; YU Yan


    Using an emulsification-gelation method,chitosansodium alginate-porcine hemoglobin microcapsules were prepared.Results show that these microcapsules have better forms and small granules with 1 μm size of the mean particle size.They possess a relatively narrow and normal Gaussian distribution.The loading efficiency of porcine hemoglobin (pHb) in microcapsules is more than 90%.The pHb released from microcapsules is extended for more than one month.Chitosan-sodium alginate-hemoglobin microcapsules are expected to become an artificial oxygen-carrying therapeutic agent with sustained release for intravenous injection.

  1. Hyperspectral imaging for dermal hemoglobin spectroscopy (United States)

    Dwyer, Peter J.; DiMarzio, Charles A.


    It has been shown previously that images collected at selected wavelengths in a sufficiently narrow bandwidth can be used to produce maps of the oxygen saturation of hemoglobin in the dermis. A four-wavelength algorithm has been developed based on a two-layer model of the skin, in which the blood is contained in the lower layer (dermis), while the upper layer attenuates some of the reflection and adds a clutter term. In the present work, the algorithm is compared analytically to simpler algorithms using three wavelengths and based on a single-layer model. It is shown through Monte-Carlo models that, for typical skin, the single-layer model is adequate to analyze data from fiber-optical reflectance spectroscopy, but the two-layer model produces better results for imaging systems. Although the model does not address the full complexity of reflectance of a two-layer skin, it has proven to be sufficient to recover the oxygen saturation, and perhaps other medically relevant information. The algorithm is demonstrated on a suction blister, where the epidermis is removed to reveal the underlying dermis. Applications for this imaging modality exist in dermatology, in surgery, and in developing treatment plans for various diseases.

  2. Glycosylated hemoglobin and hyperbaric oxygen coverage denials. (United States)

    Moffat, A D; Worth, E R; Weaver, L K


    Some Medicaid and Medicare fiscal intermediaries are denying hyperbaric oxygen (HBO2) therapy for diabetic foot ulcer (DFU) patients if the glycosylated hemoglobin (HbA1c) > 7.0%. We performed multiple PubMed searches for any diabetic wound healing clinical trial that documented HbA1c and had a wound healing endpoint. We scrutinized 30 peer-reviewed clinical trials, representing more than 4,400 patients. The average HbA1c from the intervention side of the studies was 8.6% (7.2% - 9.9%) and the control/sham side was 8.3% (6.0% - 10.6%). Twelve studies made a direct attempt to link HbA1c and wound healing. Four retrospective studies and one prospective cohort study assert that lower HbA1c favors wound healing, but review of the studies reveal design flaws that invalidate these conclusions. In total, 25 studies showed no direct correlation between HbA1c levels and wound healing. There was no randomized controlled trial (RCT) data demonstrating that HbA1c 7.0% is unfounded.

  3. Comparison of Hemoglobin A1c assay performance on two different commercial systems

    Directory of Open Access Journals (Sweden)

    Jozo Ćorić


    Full Text Available Introduction: Glycated hemoglobin (HbA1c is formed by non-enzymatic binding of glucose to the free amino group of the N-terminal end of the ß-chain of hemoglobin A. HbA1c is representative of the mean blood glucose level over three months. The aim of the study was to evaluate the Hemoglobin A1c immunoturbidimetric assay performance on two different commercial systems.Methods: We evaluated the precision and trueness for determination of HbA1c in whole blood. Concentrations of total hemoglobin and HbA1c were evaluated on Dimension Xpand (Siemens and Cobas 501 (Roche analyzers. HbA1c was measured in a latex agglutination inhibition test. Commercial controls Liquichek Diabetes Control Level 1 and Liquichek Diabetes Control Level 2 (Bio Rad at two levels were used for quality control. Analytical validation of HbA1c included: within-run imprecision, between-day imprecision, inaccuracy and comparison determination on the human samples on 2 systems: Dimension Xpand and Cobas 501 analyzers. Results: Within-run imprecision on the commercially controls for Level 1 is 4.5% and Level 2 is 3.2% between-day imprecision on commercially controls is 6.1% Level 1 and 5.1% Level 2 for respectively inac- curacy on commercially controls for Level 1 is 1.8% and Level 2 is 4.8%. Method comparison on human samples shows the correlation coefficient of 0.99.Conclusion: The presented results of the analytical evaluation methods for the determination of HbA1c showed an acceptable accuracy and precision.

  4. Structural and Mechanistic Insights into Hemoglobin-catalyzed Hydrogen Sulfide Oxidation and the Fate of Polysulfide Products

    Energy Technology Data Exchange (ETDEWEB)

    Vitvitsky, Victor; Yadav, Pramod K.; An, Sojin; Seravalli, Javier; Cho, Uhn-Soo; Banerjee, Ruma (Michigan-Med); (UNL)


    Hydrogen sulfide is a cardioprotective signaling molecule but is toxic at elevated concentrations. Red blood cells can synthesize H2S but, lacking organelles, cannot dispose of H2S via the mitochondrial sulfide oxidation pathway. We have recently shown that at high sulfide concentrations, ferric hemoglobin oxidizes H2S to a mixture of thiosulfate and iron-bound polysulfides in which the latter species predominates. Here, we report the crystal structure of human hemoglobin containing low spin ferric sulfide, the first intermediate in heme-catalyzed sulfide oxidation. The structure provides molecular insights into why sulfide is susceptible to oxidation in human hemoglobin but is stabilized against it in HbI, a specialized sulfide-carrying hemoglobin from a mollusk adapted to life in a sulfide-rich environment. We have also captured a second sulfide bound at a postulated ligand entry/exit site in the α-subunit of hemoglobin, which, to the best of our knowledge, represents the first direct evidence for this site being used to access the heme iron. Hydrodisulfide, a postulated intermediate at the junction between thiosulfate and polysulfide formation, coordinates ferric hemoglobin and, in the presence of air, generated thiosulfate. At low sulfide/heme iron ratios, the product distribution between thiosulfate and iron-bound polysulfides was approximately equal. The iron-bound polysulfides were unstable at physiological glutathione concentrations and were reduced with concomitant formation of glutathione persulfide, glutathione disulfide, and H2S. Hence, although polysulfides are unlikely to be stable in the reducing intracellular milieu, glutathione persulfide could serve as a persulfide donor for protein persulfidation, a posttranslational modification by which H2S is postulated to signal.

  5. Purification of hemoglobin by tangential flow filtration with diafiltration. (United States)

    Elmer, Jacob; Harris, David R; Sun, Guoyong; Palmer, Andre F


    A recent study by Palmer, Sun, and Harris (Biotechnol. Prog., 25:189-199, 2009) demonstrated that tangential flow filtration (TFF) can be used to produce HPLC-grade bovine and human hemoglobin (Hb). In this current study, we assessed the quality of bovine Hb (bHb) purified by introducing a 10 L batch-mode diafiltration step to the previously mentioned TFF Hb purification process. The bHb was purified from bovine red blood cells (RBCs) by filtering clarified RBC lysate through 50 nm (stage I) and 500 kDa (stage II) hollow fiber (HF) membranes. The filtrate was then passed through a 100 kDa (stage III) HF membrane with or without an additional 10 L diafiltration step to potentially remove additional small molecular weight impurities. Protein assays, SDS-PAGE, and LC-MS of the purified bHb (stage III retentate) reveal that addition of a diafiltration step has no effect on bHb purity or yield; however, it does increase the methemoglobin level and oxygen affinity of purified bHb. Therefore, we conclude that no additional benefit is gained from diafiltration at stage III and a three stage TFF process is sufficient to produce HPLC-grade bHb.

  6. Astyanax scabripinnis (Pisces: Characidae hemoglobins: structure and function

    Directory of Open Access Journals (Sweden)


    Full Text Available Electrophoretic patterns of hemoglobins, Root effect, Bohr effect in blood and stripped hemoglobin, Hb-O2 affinity GTP modulation of Astyanax scabripinnis (lambari, caught at three different altitudes in Ribeirão Grande, near Campos do Jordão (São Paulo, are described. All populations showed the same electrophoretic patterns: two cathodal components in starch gel. Normal Bohr effect values were found in these three populations both in blood (phi = -0,11 and stripped hemoglobin (phi = -0,12. Different blood O2 affinities collected in fish of these 3 populations were detected. GTP has a large influence on Hb-O2 binding properties in A. scabripinnis. Stripped hemoglobin shows small Root effect. The addition of triphosphated nucleotides increases this effect. GTP is more effective than ATP on enhancing Root effect. Oxygen availability in water can be the factor responsible for differences found in blood O2 affinity.

  7. Postpartum hemorrhage is related to the hemoglobin levels at labor ...

    African Journals Online (AJOL)

    Kaima A. Frass


    Jan 6, 2015 ... tion (Hb < 10) during emergency cesarean delivery and to assess the Hb level at which .... hemoglobin and oxygen to uterus causing tissue enzymes and ... loon tamponade and systemic pelvic devascularization were.

  8. Lower versus Higher Hemoglobin Threshold for Transfusion in Septic Shock

    DEFF Research Database (Denmark)

    Holst, Lars B; Haase, Nicolai; Wetterslev, Jørn;


    BACKGROUND: Blood transfusions are frequently given to patients with septic shock. However, the benefits and harms of different hemoglobin thresholds for transfusion have not been established. METHODS: In this multicenter, parallel-group trial, we randomly assigned patients in the intensive care...... unit (ICU) who had septic shock and a hemoglobin concentration of 9 g per deciliter or less to receive 1 unit of leukoreduced red cells when the hemoglobin level was 7 g per deciliter or less (lower threshold) or when the level was 9 g per deciliter or less (higher threshold) during the ICU stay...... were similar in the two intervention groups. CONCLUSIONS: Among patients with septic shock, mortality at 90 days and rates of ischemic events and use of life support were similar among those assigned to blood transfusion at a higher hemoglobin threshold and those assigned to blood transfusion...

  9. Thalassemia and Hemoglobin E in Southern Thai Blood Donors


    Manit Nuinoon; Kwanta Kruachan; Warachaya Sengking; Dararat Horpet; Ubol Sungyuan


    Thalassemia and hemoglobin E (Hb E) are common in Thailand. Individuals with thalassemia trait usually have a normal hemoglobin concentration or mild anemia. Therefore, thalassemic individuals who have minimum acceptable Hb level may be accepted as blood donors. This study was aimed at determining the frequency of α-thalassemia 1 trait, β-thalassemia trait, and Hb E-related syndromes in Southern Thai blood donors. One hundred and sixteen voluntary blood donors, Southern Thailand origin, were ...

  10. Effects of thyroid status on glycated hemoglobin

    Directory of Open Access Journals (Sweden)

    Rana Bhattacharjee


    Full Text Available Introduction: Glycated hemoglobin (HbA1c can be altered in different conditions. We hypothesize that HbA1c levels may change due to altered thyroid status, possibly due to changes in red blood cell (RBC turnover. Objectives: The objective of this study was to determine the effects of altered thyroid status on HbA1c levels in individuals without diabetes, with overt hyper- and hypo-thyroidism, and if present, whether such changes in HbA1c are reversed after achieving euthyroid state. Methods: Euglycemic individuals with overt hypo- or hyper-thyroidism were selected. Age- and sex-matched controls were recruited. Baseline HbA1c and reticulocyte counts (for estimation of RBC turnover were estimated in all the patients and compared. Thereafter, stable euthyroidism was achieved in a randomly selected subgroup and HbA1c and reticulocyte count was reassessed. HbA1c values and reticulocyte counts were compared with baseline in both the groups. Results: Hb A1c in patients initially selected was found to be significantly higher in hypothyroid group. HbA1c values in hyperthyroid patients were not significantly different from controls. HbA1c reduction and rise in reticulocyte count were significant in hypothyroid group following treatment without significant change in glucose level. Hb A1c did not change significantly following treatment in hyperthyroid group. The reticulocyte count, however, decreased significantly. Conclusion: Baseline HbA1c levels were found to be significantly higher in hypothyroid patients, which reduced significantly after achievement of euthyroidism without any change in glucose levels. Significant baseline or posttreatment change was not observed in hyperthyroid patients. Our study suggests that we should be cautious while interpreting HbA1c data in patients with hypothyroidism.

  11. Hemoglobin Screening Independently Predicts All-Cause Mortality. (United States)

    Fulks, Michael; Dolan, Vera F; Stout, Robert L


    Objective .- Determine if the addition of hemoglobin testing improves risk prediction for life insurance applicants. Method .- Hemoglobin results for insurance applicants tested from 1993 to 2007, with vital status determined by Social Security Death Master File follow-up in 2011, were analyzed by age and sex with and without accounting for the contribution of other test results. Results .- Hemoglobin values ≤12.0 g/dL (and possibly ≤13.0 g/dL) in females age 50+ (but not age 15.0 g/dL (and possibly >14.0 g/dL) for all females and for hemoglobin values >16.0 g/dL for males. Conclusion .- Hemoglobin testing can add additional independent risk assessment to that obtained from other laboratory testing, BP and build in this relatively healthy insurance applicant population. Multiple studies support this finding at older ages, but data (and the prevalence of diseases impacting hemoglobin levels) are limited at younger ages.

  12. Assessment of vaccine-induced CD4 T cell responses to the 119-143 immunodominant region of the tumor-specific antigen NY-ESO-1 using DRB1*0101 tetramers. (United States)

    Ayyoub, Maha; Pignon, Pascale; Dojcinovic, Danijel; Raimbaud, Isabelle; Old, Lloyd J; Luescher, Immanuel; Valmori, Danila


    NY-ESO-1 (ESO), a tumor-specific antigen of the cancer/testis group, is presently viewed as an important model antigen for the development of generic anticancer vaccines. The ESO(119-143) region is immunodominant following immunization with a recombinant ESO vaccine. In this study, we generated DRB1*0101/ESO(119-143) tetramers and used them to assess CD4 T-cell responses in vaccinated patients expressing DRB1*0101 (DR1). We generated tetramers of DRB1*0101 incorporating peptide ESO(119-143) using a previously described strategy. We assessed ESO(119-143)-specific CD4 T cells in peptide-stimulated postvaccine cultures using the tetramers. We isolated DR1/ESO(119-143) tetramer(+) cells by cell sorting and characterized them functionally. We assessed vaccine-induced CD4(+) DR1/ESO(119-143) tetramer(+) T cells ex vivo and characterized them phenotypically. Staining of cultures from vaccinated patients with DR1/ESO(119-143) tetramers identified vaccine-induced CD4 T cells. Tetramer(+) cells isolated by cell sorting were of T(H)1 type and efficiently recognized full-length ESO. We identified ESO(123-137) as the minimal optimal epitope recognized by DR1-restricted ESO-specific CD4 T cells. By assessing DR1/ESO(119-143) tetramer(+) cells using T cell receptor (TCR) β chain variable region (Vβ)-specific antibodies, we identified several frequently used Vβ. Finally, direct ex vivo staining of patients' CD4 T cells with tetramers allowed the direct quantification and phenotyping of vaccine-induced ESO-specific CD4 T cells. The development of DR1/ESO(119-143) tetramers, allowing the direct visualization, isolation, and characterization of ESO-specific CD4 T cells, will be instrumental for the evaluation of spontaneous and vaccine-induced immune responses to this important tumor antigen in DR1-expressing patients. ©2010 AACR.

  13. The primary structure of the hemoglobin of Malayan sun bear (Helarctos malayanus, Carnivora) and structural comparison to other hemoglobin sequences. (United States)

    Hofmann, O; Braunitzer, G; Göltenboth, R


    The complete primary structure of the alpha- and beta-chains of the hemoglobin of Malayan Sun Bear (Helarctos malayanus) is presented. After cleavage of the heme-protein link and chain separation by RP-HPLC, amino-acid sequences were determined by Edman degradation in liquid- and gas-phase sequenators. An interesting result of this work is the demonstration that the hemoglobin of Malayan Sun Bear is identical to the hemoglobins of Polar Bear (Ursus maritimus) and Asiatic Black Bear (Ursus tibetanus). The paper gives an updated table of identical hemoglobin chains from different species. This paper may be considered as a compilation of work on the genetic relationship of Pandas.

  14. More tricks with tetramers

    DEFF Research Database (Denmark)

    Dolton, Garry; Tungatt, Katie; Lloyd, Angharad


    Analysis of antigen-specific T-cell populations by flow cytometry with peptide-MHC (pMHC) multimers is now commonplace. These reagents allow the tracking and phenotyping of T cells during infection, autoimmunity and cancer, and can be particularly revealing when used for monitoring therapeutic...... interventions. In 2009, we reviewed a number of 'tricks' that could be used to improve this powerful technology. More recent advances have demonstrated the potential benefits of using higher order multimers and of 'boosting' staining by inclusion of an antibody against the pMHC multimer. These developments now...... allow staining of T cells where the interaction between the pMHC and the T-cell receptor is over 20-fold weaker (K(D) > 1 mm) than could previously be achieved. Such improvements are particularly relevant when using pMHC multimers to stain anti-cancer or autoimmune T-cell populations, which tend to bear...

  15. Expression and purification of recombinant hemoglobin in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Chandrasekhar Natarajan

    Full Text Available BACKGROUND: Recombinant DNA technologies have played a pivotal role in the elucidation of structure-function relationships in hemoglobin (Hb and other globin proteins. Here we describe the development of a plasmid expression system to synthesize recombinant Hbs in Escherichia coli, and we describe a protocol for expressing Hbs with low intrinsic solubilities. Since the α- and β-chain Hbs of different species span a broad range of solubilities, experimental protocols that have been optimized for expressing recombinant human HbA may often prove unsuitable for the recombinant expression of wildtype and mutant Hbs of other species. METHODOLOGY/PRINCIPAL FINDINGS: As a test case for our expression system, we produced recombinant Hbs of the deer mouse (Peromyscus maniculatus, a species that has been the subject of research on mechanisms of Hb adaptation to hypoxia. By experimentally assessing the combined effects of induction temperature, induction time and E. coli expression strain on the solubility of recombinant deer mouse Hbs, we identified combinations of expression conditions that greatly enhanced the yield of recombinant protein and which also increased the efficiency of post-translational modifications. CONCLUSION/SIGNIFICANCE: Our protocol should prove useful for the experimental study of recombinant Hbs in many non-human animals. One of the chief advantages of our protocol is that we can express soluble recombinant Hb without co-expressing molecular chaperones, and without the need for additional reconstitution or heme-incorporation steps. Moreover, our plasmid construct contains a combination of unique restriction sites that allows us to produce recombinant Hbs with different α- and β-chain subunit combinations by means of cassette mutagenesis.

  16. Structural and functional characterization of Delphinus delphis hemoglobin system. (United States)

    Manconi, Barbara; Messana, Irene; Maggiani, Federica; Olianas, Alessandra; Pellegrini, Mariagiuseppina; Crnjar, Roberto; Castagnola, Massimo; Giardina, Bruno; Sanna, Maria Teresa


    Structural analysis of the hemoglobin (Hb) system of Delphinus delphis revealed a high globin multiplicity: HPLC-electrospray ionization-mass spectrometry (ESI-MS) analysis evidenced three major beta (beta1 16,022 Da, beta2 16,036 Da, beta3 16,036 Da, labeled according to their progressive elution times) and two major alpha globins (alpha1 15,345 Da, alpha2 15,329 Da). ESI-tandem mass and nucleotide sequence analyses showed that beta2 globin differs from beta1 for the substitution Val126 --> Leu, while beta3 globin differs from beta2 for the isobaric substitution Lys65 --> Gln. The alpha2 globin differs from the alpha1 for the substitution Ser15 --> Ala. Anion-exchange chromatography allowed the separation of two Hb fractions and HPLC-ESI-MS analysis revealed that the fraction with higher pI (HbI) contained beta1, beta2 and both the alpha globins, and the fraction with lower pI (HbII) contained beta3 and both the alpha globins. Both D. delphis Hb fractions displayed a lower intrinsic oxygen affinity, a decreased effect of 2,3-BPG and a reduced cooperativity with respect to human HbA(0), with HbII showing the more pronounced differences. With respect to HbA(0), either the substitution Probeta5 --> Gly or the Probeta5 --> Ala is present in all the cetacean beta globins sequenced so far, and it has been hypothesized that position 5 of beta globins may have a role in the interaction with 2,3-BPG. Regarding the particularly lowered cooperativity of HbII, it is interesting to observe that the variant human HbA, characterized by the substitution Lysbeta65 --> Gln (HbJ-Cairo) has a decreased cooperativity with respect to HbA(0).

  17. Diffuse optical spectroscopy monitoring of oxygen state and hemoglobin concentration during SKBR-3 tumor model growth (United States)

    Orlova, A. G.; Kirillin, M. Yu; Volovetsky, A. B.; Shilyagina, N. Yu; Sergeeva, E. A.; Golubiatnikov, G. Yu; Turchin, I. V.


    Tumor oxygenation and hemoglobin content are the key indicators of the tumor status which can be efficiently employed for prognosis of tumor development and choice of treatment strategy. We report on monitoring of these parameters in SKBR-3 (human breast adenocarcinoma) tumors established as subcutaneous tumor xenografts in athymic nude mice by diffuse optical spectroscopy (DOS). A simple continuous wave fiber probe DOS system is employed. Optical properties extraction approach is based on diffusion approximation. Statistically significant difference between measured values of normal tissue and tumor are demonstrated. Hemoglobin content in tumor increases from 7.0  ±  4.2 μM to 30.1  ±  16.1 μM with tumor growth from 150  ±  80 mm3 to 1300  ±  650 mm3 which is determined by gradual increase of deoxyhemoglobin content while measured oxyhemoglobin content does not demonstrate any statistically significant variations. Oxygenation in tumor falls quickly from 52.8  ±  24.7% to 20.2  ±  4.8% preceding acceleration of tumor growth. Statistical analysis indicated dependence of oxy-, deoxy- and total hemoglobin on tumor volume (p  Pearson’s correlation coefficient equals 0.8).

  18. Effects of spermine NONOate and ATP on the thermal stability of hemoglobin

    Directory of Open Access Journals (Sweden)

    Bassam Rasha


    Full Text Available Abstract Background Minor changes in protein structure induced by small organic and inorganic molecules can result in significant metabolic effects. The effects can be even more profound if the molecular players are chemically active and present in the cell in considerable amounts. The aim of our study was to investigate effects of a nitric oxide donor (spermine NONOate, ATP and sodium/potassium environment on the dynamics of thermal unfolding of human hemoglobin (Hb. The effect of these molecules was examined by means of circular dichroism spectrometry (CD in the temperature range between 25°C and 70°C. The alpha-helical content of buffered hemoglobin samples (0.1 mg/ml was estimated via ellipticity change measurements at a heating rate of 1°C/min. Results Major results were: 1 spermine NONOate persistently decreased the hemoglobin unfolding temperature Tuirrespectively of the Na + /K + environment, 2 ATP instead increased the unfolding temperature by 3°C in both sodium-based and potassium-based buffers and 3 mutual effects of ATP and NO were strongly influenced by particular buffer ionic compositions. Moreover, the presence of potassium facilitated a partial unfolding of alpha-helical structures even at room temperature. Conclusion The obtained data might shed more light on molecular mechanisms and biophysics involved in the regulation of protein activity by small solutes in the cell.

  19. The postnatal decline of hemoglobin F synthesis in normal full-term infants. (United States)

    Bard, H


    Studies were carried out during the 1st yr of life in normal infants born at term to determine the proportions of fetal hemoglobin (Hb F) and adult hemoglobin (Hb A) being synthesized, in order to describe the complete switchover from Hb F to Hb A synthesis during postnatal life. 53 blood samples from 37 infants were incubated in an amino acid mixture containing [14C]leucine and chromatographed on DEAE-Sephadex for separation of Hb F and Hb A fractions. The completeness of the CEAE-Sephadex separation of Hb A and Hb F at an age when the major portion of synthesis was of the adult type of hemoglobin was confirmed by globin chain chromatography with the use of carboxylmethyl cellulose. There was a rapid decline in Hb F synthesis postnatally until 16-20 wk of age when levels of 3.2% plus or minus SD 2.1% were reached. By combining this data with that previously published, the complete switchover from Hb F to Hb A synthesis can be described in humans in relation to postconceptional age. It follows a sigmoid curve; the steep portion, which lies between the 30th and 52nd postconceptional week, is preceded and follwoed by plateaus averaging 95% and 7% Hb F synthesis, respectively.

  20. Identification of a haptoglobin-hemoglobin complex in the Alaskan Least Cisco (Coregonus sardinella). (United States)

    Wahl, S M; Boger, J K; Michael, V; Duffy, L K


    The hemoglobin and a hemoglobin binding protein have been characterized in the Arctic fish (Coregonus sardinella). The evolutionary significance of the hemoglobin and plasma protein differences between fish and mammals is still unresolved. Blood samples from the Alaskan Least Cisco were separated into plasma and hemoglobin fractions and the proteins in these fractions were analyzed both by alkaline agarose gel electrophoresis, by isolelectric focusing, and by capillary electrophoresis. Staining the plasma proteins gels with o-dianisidine revealed hemoglobin containing protein complexes. A hemoglobin-containing band was observed in hemolyzed plasma which did not migrate with free hemoglobin, and is believed to be hemoglobin-haptoglobin complex. Size exclusion chromatography further characterized the hemoglobin as disassociating freely into dimers, and hemoglobin-haptoglobin complex having a molecular weight greater then 200,000 daltons.

  1. Quantitation of Anaplasma marginale major surface protein (MSP)1a and MSP2 epitope-specific CD4+ T lymphocytes using bovine DRB3*1101 and DRB3*1201 tetramers. (United States)

    Norimine, Junzo; Han, Sushan; Brown, Wendy C


    Antigen-specific CD4+ T cells play a critical role in protective immunity to many infectious pathogens. Although the antigen-specific CD4+ T cells can be measured by functional assays such as proliferation or cytokine enzyme-linked immunospot, such assays are limited to a specific function and cannot quantify anergic or suppressed T cells. In contrast, major histocompatiblity complex (MHC) class II tetramers can enumerate epitope-specific CD4+ T cells independent of function. In this paper, we report the construction of bovine leukocyte antigen MHC class II tetramers using a novel mammalian cell system to express soluble class II DRA/DRB3 molecules and defined immunodominant peptide epitopes of Anaplasma marginale major surface proteins (MSPs). Phycoerythrin-labeled tetramers were either loaded with exogenous peptide or constructed with the peptide epitope linked to the N terminus of the DRB3 chain. A DRB3*1101 tetramer loaded with MSP1a peptide F2-5B (ARSVLETLAGHVDALG) and DRB3*1201 tetramers loaded with MSP1a peptide F2-1-1b (GEGYATYLAQAFA) or MSP2 peptide P16-7 (NFAYFGGELGVRFAF) specifically stained antigen-specific CD4+ T cell lines and clones. Tetramers constructed with the T-cell epitope linked to the DRB3 chain were slightly better at labeling CD4+ T cells. In one cell line, the number of tetramer-positive T cells increased to approximately 94% of the CD4+ T cells after culture for 21 weeks with specific antigen. This novel technology should be useful to track the fate of antigen-specific CD4+ T-cell responses in cattle after immunization or infection with persistent pathogens, such as A. marginale, that modulate the host immune response.

  2. Probing the Subunit-Subunit Interaction of the Tetramer of E. coli KDO8P Synthase by Electrospray Ionization Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    LI Zhili; SAU,Apurba Kumar


    Escherichia coli 3-Deoxy-D-manno-octulosonate 8-phosphate (KDO8P) synthase catalyzes the condensation reaction between D-arabinose 5-phosphate (A5P) and phosphoenolpyruvate (PEP) to form KDO8P and inorganic phosphate (Pi).This enzyme exists as a tetramer in solution, which is important for catalysis. Two different states of the enzyme were obtained: i) PEP-bound and ii) PEP-unbound. The effect of the substrates and products on the overall structure of KDO8P synthase in both PEP-bound and unbound states was examined using electrospray ioni-zation mass spectrometry. The analysis of our data showed that the complexes of the PEP-unbound enzyme with PEP (or P,) favored the formation of monomers, while the complexes with A5P (or KDO8P) mainly favored dimers. The PEP-bound enzyme was found to exist in the monomer and dimer with a small amount of the tetramer, whereas the PEP-unbound form primarily exists in the monomer and dimer, and no tetramer was observed, suggesting that the bound PEP have a role in stabilization of the tetrameric structure. Taken together, the results imply that the ad-dition of the substrates or products to the unbound enzyme may alter the subunit-subunit interactions and/or con-formational change of the protein at the active site, and this study also demonstrates that the electrospray ionization mass spectrometric method may be a powerful tool in probing the subunit-subunit interactions and/or conforma-tional change of multi-subunit protein upon binding to ligand.

  3. Plant hemoglobins: Important players at the crossroads between oxygen and nitric oxide

    DEFF Research Database (Denmark)

    Gupta, Kapuganti J; Hebelstrup, Kim; Mur, Luis A J


    Plant hemoglobins constitute a diverse group of hemeproteins and evolutionarily belong to three different classes. Class 1 hemoglobins possess an extremely high affinity to oxygen and their main function consists in scavenging of nitric oxide (NO) at very low oxygen levels. Class 2 hemoglobins have...... at high O2 concentrations. Depending on their physical properties, hemoglobins belong either to hexacoordinate non-symbiotic or pentacoordinate symbiotic groups. Plant hemoglobins are plausible targets for improving resistance to multiple stresses....

  4. Feasibility of Electrospinning the Globular Proteins Hemoglobin and Myoglobin

    Directory of Open Access Journals (Sweden)

    Catherine P. Barnes


    Full Text Available Various concentrations of the globular protein hemoglobin were successfully electrospun to create micro-fibrous mats of varying physical and mechanical characteristics. The electrospinning parameters are reported. One concentration of myoglobin was electrospun into a mat for comparison to the hemoglobin mats. Scanning electron microscopy revealed ribbon-like morphologies for the hemoglobin and myoglobin structures. Mean fiber width and thickness for each mat electrospun from a different hemoglobin concentration increased from 2.68 ± 0.83 to 3.55 ± 1.49 μm and from 0.49 ± 0.08 to 0.99 ± 0.41 μm, respectively, for increasing hemoglobin solution concentrations (from 150 to 225 mg/mL. For calculations of surface area to volume ratio for the four different electrospun hemoglobin concentrations, there was a negative correlation (r = -0.84 with concentration; the surface area to volume ratio ranged between 0.50 ± 0.16 and 1.53 ± 0.24 m2/cm3. Also, there appears to be a positive correlation between electrospun hemoglobin concentration and porosity, which increased with increasing concentration from 69.5 to 83.3 %. Following cross-linking with glutaraldehyde, the mechanical properties of two constructs were evaluated via uniaxial tensile testing to demonstrate handling capability. Results indicated that increased cross-linking time produced stiffer structures, as peak stress and modulus increased while strain at break decreased when the mats were cross-linked for 30 minutes with glutaraldehyde versus the 20 minute cross-linking time.

  5. Vaticaffinol, a resveratrol tetramer, exerts more preferable immunosuppressive activity than its precursor in vitro and in vivo through multiple aspects against activated T lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Li-Li; Wu, Xue-Feng; Liu, Hai-Liang; Guo, Wen-Jie; Luo, Qiong; Tao, Fei-Fei; Ge, Hui-Ming; Shen, Yan; Tan, Ren-Xiang; Xu, Qiang, E-mail:; Sun, Yang, E-mail:


    In the present study, we aimed to investigate the immunosuppressive activity of vaticaffinol, a resveratrol tetramer isolated from Vatica mangachapoi, on T lymphocytes both in vitro and in vivo, and further explored its potential molecular mechanism. Resveratrol had a wide spectrum of healthy beneficial effects with multiple targets. Interestingly, its tetramer, vaticaffinol, exerted more intensive immunosuppressive activity than resveratrol. Vaticaffinol significantly inhibited T cells proliferation activated by concanavalin A (Con A) or anti-CD3 plus anti-CD28 in a dose- and time-dependent manner. It also induced Con A-activated T cells undergoing apoptosis through mitochondrial pathway. Moreover, this compound prevented cells from entering S phase and G2/M phase during T cells activation. In addition, vaticaffinol inhibited ERK and AKT signaling pathways in Con A-activated T cells. Furthermore, vaticaffinol significantly ameliorated ear swelling in a mouse model of picryl chloride-induced ear contact dermatitis in vivo. In most of the aforementioned experiments, however, resveratrol had only slight effects on the inhibition of T lymphocytes compared with vaticaffinol. Taken together, our findings suggest that vaticaffinol exerts more preferable immunosuppressive activity than its precursor resveratrol both in vitro and in vivo by affecting multiple targets against activated T cells. - Graphical abstract: Vaticaffinol, a resveratrol tetramer isolated from Vatica mangachapoi, exerts more intensive immunosuppressive activity than its precursor resveratrol does in vitro and in vivo. Its mechanism may involve multiple effects against activated T cells: regulation of signalings involved in cell proliferation, G0/G1 arrest of T cells, as well as an apoptosis induction in activated effector T cells. Highlights: ► Vaticaffinol, a resveratrol tetramer, exerts more potent activity than its precursor. ► It inhibited T cells proliferation and prevented them from entering

  6. Classification and regression tree (CART analyses of genomic signatures reveal sets of tetramers that discriminate temperature optima of archaea and bacteria

    Directory of Open Access Journals (Sweden)

    Betsey Dexter Dyer


    Full Text Available Classification and regression tree (CART analysis was applied to genome-wide tetranucleotide frequencies (genomic signatures of 195 archaea and bacteria. Although genomic signatures have typically been used to classify evolutionary divergence, in this study, convergent evolution was the focus. Temperature optima for most of the organisms examined could be distinguished by CART analyses of tetranucleotide frequencies. This suggests that pervasive (nonlinear qualities of genomes may reflect certain environmental conditions (such as temperature in which those genomes evolved. The predominant use of GAGA and AGGA as the discriminating tetramers in CART models suggests that purine-loading and codon biases of thermophiles may explain some of the results.

  7. Hemoglobin Wood beta97(FG4) His replaced by Leu. A new high-oxygen-affinity hemoglobin associated with familial erythrocytosis. (United States)

    Taketa, F; Huang, Y P; Libnoch, J A; Dessel, B H


    The characterization of hemoglobin Wood (beta97(FG4) His replaced by Leu), a high oxygen affinity hemoglobin with reduced Hill constant is described. The amino acid substitution occurs at the alpha1beta2 interface, in the same position as in hemoglobin Malmö (beta97(FG4) His replaced by Gln) and in an homologous position when compared with hemoglobins Chesapeake (alpha92(FG4) Arg replaced by Leu) and J. Capetown (alpha92(fg4) arg replaced by Gln).

  8. Selection of aptamers specific for glycated hemoglobin and total hemoglobin using on-chip SELEX. (United States)

    Lin, Hsin-I; Wu, Ching-Chu; Yang, Ching-Hsuan; Chang, Ko-Wei; Lee, Gwo-Bin; Shiesh, Shu-Chu


    Blood glycated hemoglobin (HbA1c) levels reflecting average glucose concentrations over the past three months are fundamental for the diagnosis, monitoring, and risk assessment of diabetes. It has been hypothesized that aptamers, which are single-stranded DNAs or RNAs that demonstrate high affinity to a large variety of molecules ranging from small drugs, metabolites, or proteins, could be used for the measurement of HbA1c. Aptamers are selected through an in vitro process called systematic evolution of ligands by exponential enrichment (SELEX), and they can be chemically synthesized with high reproducibility at relatively low costs. This study therefore aimed to select HbA1c- and hemoglobin (Hb)-specific single-stranded DNA aptamers using an on-chip SELEX protocol. A microfluidic SELEX chip was developed to continuously and automatically carry out multiple rounds of SELEX to screen specific aptamers for HbA1c and Hb. HbA1c and Hb were first coated onto magnetic beads. Following several rounds of selection and enrichment with a randomized 40-mer DNA library, specific oligonucleotides were selected. The binding specificity and affinity were assessed by competitive and binding assays. Using the developed microfluidic system, the incubation and partitioning times were greatly decreased, and the entire process was shortened dramatically. Both HbA1c- and Hb-specific aptamers selected by the microfluidic system showed high specificity and affinity (dissociation constant, Kd = 7.6 ± 3.0 nM and 7.3 ± 2.2 nM for HbA1c and Hb, respectively). With further refinements in the assay, these aptamers may replace the conventional antibodies for in vitro diagnostics applications in the near future.

  9. Static and dynamic light scattering approach to the hydration of hemoglobin and its supertetramers in the presence of osmolites. (United States)

    Arosio, Daniele; Kwansa, Herman E; Gering, Henry; Piszczek, Grzegorz; Bucci, Enrico


    We used static and dynamic light scattering for comparing the mass (MW) and hydrodynamic radius (R(h)) of several hemoglobin systems, namely human hemoglobin, bovine hemoglobin, human hemoglobin cross-linked with a sebacyl residue, and bovine hemoglobin cross-linked with an adipoyl residue. We measured the MW and R(h) of these systems in 0.1M phosphate buffer at pH 7.0 in the absence and in the presence of either betaine or glycerol up to 1.7 molal concentrations. The 90 degrees scattering was measured with a photon counting machine equipped with a diode laser at 783 nm. The Rayleigh ratio [R(theta)] of the instrument was estimated using R(theta) = 7.19E-6 cm(-1) for toluene at 783 nm. The refractive index increment of hemoglobin solutions was measured using a laser beam at 750 nm. We estimated a value dn/dc = 0.210 cm3/g in the absence and dn/dc = 0.170 in the presence of 1.7 molal osmolites. For all systems both in liganded and unliganded form, the static light scattering data showed a 16% mass increase with increasing concentration of osmolites. The hydrodynamic radii of all investigated systems in the presence and absence of osmolites were close to 3.17 nm. Assuming a partial specific volume nu = 0.739 for hemoglobin, and using spherical geometry, the estimated average hydration volume of hemoglobin was 32.6 L/mole in the absence of osmolites. It decreased to 23.5 L/mole in the presence of 1.7 molal osmolites. Assuming that the density of water in the hydration volume is D = 1.0 g/cm3, the hydration of Hb was 0.51 gH2O/gHb, with a surface density of 0.20 molH2O/A2. The hydration decreased to 0.33 gH2O/gHb and 0.14 molH2O/A2 in the presence of 1.7 molal osmolites. The decreased hydration was compensated by the increased mass (i.e., decreased surface area per unit volume) so that the thickness of the water shell around these proteins remained close to a single layer of water molecules. These findings indicate that the combination of static and dynamic light

  10. Hemoglobin values for pregnant women residing at middle altitude

    Directory of Open Access Journals (Sweden)

    Mercedes Jatziri Gaitán-González


    Full Text Available Objective. To determine maternal hemoglobin behavior during pregnancy for middle altitude residents and to compare it with that reported in other populations with or without iron supplementation. Materials and methods. Hematological values from 227 pregnant women residing at 2 240 m altitude (Mexico City, with low obstetric and perinatal risk, and receiving supplementary iron, were compared with reference values obtained from other populations of pregnant women residing at different altitudes, after correcting for altitude. Results. While the hemoglobin values for the first and second trimester of pregnancy in our studied population were similar to those reported for iron-supplemented populations (p mayor que 0.05, the third trimester values were similar to those reported for a population without this supplement (p mayor que 0.05. Conclusions. Despite receiving supplementary iron, hemoglobin values during pregnancy from women residing at middle altitude show similar behavior to that reported for pregnant women without iron supplementation.

  11. Hemoglobin is essential for normal growth of Arabidopsis organs

    DEFF Research Database (Denmark)

    Hebelstrup, Kim Henrik; Hunt, Peter; Dennis, Elizabeth


    lines are viable but show a mutant phenotype affecting the regions where AHb1 is expressed. Arabidopsis lines with an insertional knockout or overexpression of AHb2, a class II 3-on-3 hemoglobin, were generated. Seedlings overexpressing AHb2 show enhanced survival of hypoxic stress. The AHb2 knockout......In Arabidopsis thaliana, the class I hemoglobin AHb1 is transiently expressed in the hydathodes of leaves and in floral buds from young inflorescences. Nitric oxide (NO) accumulates to high levels in these organs when AHb1 is silenced, indicating an important role in metabolizing NO. AHb1-silenced...... suggests that 3-on-3 hemoglobins apart from a role in hypoxic stress play a general role under non-stressed conditions where they are essential for normal development by controlling the level of NO which tends to accumulate in floral buds and leaf hydathodes of plants...

  12. Use of "one-pot, mix-and-read" peptide-MHC class I tetramers and predictive algorithms to improve detection of cytotoxic T lymphocyte responses in cattle

    DEFF Research Database (Denmark)

    Svitek, Nicholas; Hansen, Andreas Martin; Steinaa, Lucilla


    Peptide-major histocompatibility complex (p-MHC) class I tetramer complexes have facilitated the early detection and functional characterisation of epitope specific CD8(+) cytotoxic T lymphocytes (CTL). Here, we report on the generation of seven recombinant bovine leukocyte antigens (BoLA....... parva CTL epitopes. Using an ELISA assay to measure peptide-BoLA monomer formation and p-MHC class I tetramers of new specificity, we demonstrate that a predicted alternative epitope Tp2(29-37) rather than the previously reported Tp2(27-37) epitope is the correct Tp2 epitope presented by BoLA-6......*04101. We also verified the prediction by NetMHCpan that the Tp5(87-95) epitope reported as BoLA-T5 restricted can also be presented by BoLA-1*02301, a molecule similar in sequence to BoLA-T5. In addition, Tp5(87-95) specific bovine CTL were simultaneously stained by Tp5-BoLA-1*02301 and Tp5-BoLA-T5...

  13. Structural Insights into the Association of Hif1 with Histones H2A-H2B Dimer and H3-H4 Tetramer. (United States)

    Zhang, Mengying; Liu, Hejun; Gao, Yongxiang; Zhu, Zhongliang; Chen, Zijun; Zheng, Peiyi; Xue, Lu; Li, Jixi; Teng, Maikun; Niu, Liwen


    Histone chaperones are critical for guiding specific post-transcriptional modifications of histones, safeguarding the histone deposition (or disassociation) of nucleosome (dis)assembly, and regulating chromatin structures to change gene activities. HAT1-interacting factor 1 (Hif1) has been reported to be an H3-H4 chaperone and to be involved in telomeric silencing and nucleosome (dis)assembly. However, the structural basis for the interaction of Hif1 with histones remains unknown. Here, we report the complex structure of Hif1 binding to H2A-H2B for uncovering the chaperone specificities of Hif1 on binding to both the H2A-H2B dimer and the H3-H4 tetramer. Our findings reveal that Hif1 interacts with the H2A-H2B dimer and the H3-H4 tetramer via distinct mechanisms, suggesting that Hif1 is a pivotal scaffold on alternate binding of H2A-H2B and H3-H4. These specificities are conserved features of the Sim3-Hif1-NASP interrupted tetratricopeptide repeat proteins, which provide clues for investigating their potential roles in nucleosome (dis)assembly. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Membrane-associated sickle hemoglobin: a major determinant of sickle erythrocyte rigidity. (United States)

    Evans, E A; Mohandas, N


    Micropipette aspiration tests on single erythrocytes have previously shown that the static rigidity (membrane shear modulus) of oxygenated sickle cells increased with increasing hemoglobin concentration, whereas the rigidity of normal cells was independent of hemoglobin concentration. Moreover, it was observed that after mechanical extension, sickle cells exhibited persistent deformation more frequently and to a greater extent than normal cells. To ascertain if differences in association of normal and sickle hemoglobin with the membrane could account for these observations, we measured rheologic properties of normal membranes reconstituted with sickle hemoglobin and sickle membranes reconstituted with normal hemoglobin. The static rigidity of normal ghosts reloaded with sickle hemoglobin was higher than those of either normal ghosts reloaded with normal hemoglobin or native normal cells. On the other hand, the increased rigidity of native sickle cells decreased to near-normal values following reconstitution with normal hemoglobin. Furthermore, we observed that normal ghosts reconstituted with sickle hemoglobin exhibited persistent bumps after mechanical extension, but no bumps formed on normal ghosts reconstituted with normal hemoglobin. Moreover residual bumps were not produced on sickle cells reloaded with normal hemoglobin. Since mechanical characteristics peculiar to sickle cells could be induced in normal cells by incorporation of sickle hemoglobin, and since normal characteristics could be restored to sickle cells by incorporation of normal hemoglobin, we suggest that the interaction of sickle hemoglobin with the cell membrane is responsible for augmented static rigidity of oxygenated sickle erythrocytes.

  15. Nitric oxide in plants: the roles of ascorbate and hemoglobin.

    Directory of Open Access Journals (Sweden)

    Xiaoguang Wang

    Full Text Available Ascorbic acid and hemoglobins have been linked to nitric oxide metabolism in plants. It has been hypothesized that ascorbic acid directly reduces plant hemoglobin in support of NO scavenging, producing nitrate and monodehydroascorbate. In this scenario, monodehydroascorbate reductase uses NADH to reduce monodehydroascorbate back to ascorbate to sustain the cycle. To test this hypothesis, rates of rice nonsymbiotic hemoglobin reduction by ascorbate were measured directly, in the presence and absence of purified rice monodehydroascorbate reductase and NADH. Solution NO scavenging was also measured methodically in the presence and absence of rice nonsymbiotic hemoglobin and monodehydroascorbate reductase, under hypoxic and normoxic conditions, in an effort to gauge the likelihood of these proteins affecting NO metabolism in plant tissues. Our results indicate that ascorbic acid slowly reduces rice nonsymbiotic hemoglobin at a rate identical to myoglobin reduction. The product of the reaction is monodehydroascorbate, which can be efficiently reduced back to ascorbate in the presence of monodehydroascorbate reductase and NADH. However, our NO scavenging results suggest that the direct reduction of plant hemoglobin by ascorbic acid is unlikely to serve as a significant factor in NO metabolism, even in the presence of monodehydroascorbate reductase. Finally, the possibility that the direct reaction of nitrite/nitrous acid and ascorbic acid produces NO was measured at various pH values mimicking hypoxic plant cells. Our results suggest that this reaction is a likely source of NO as the plant cell pH drops below 7, and as nitrite concentrations rise to mM levels during hypoxia.


    Directory of Open Access Journals (Sweden)

    A. A. Mokronosova


    Full Text Available Abstract. Forty four patients with persistent allergic rhinitis and sensitization to the house dust mites were observed. All the patients have been examined in conformity with international diagnostic standards. The first group of observation included fifteen patients who received intranasal therapy by flutikasone propionate nasal spray at a dose of 200 mkg once a day for two weeks. The second group of observation included fourteen patients who received 10 inhalations of Affinoleukin® (a lyophilized complex of low molecular weight proteins from human leukocyte membranes with glycine, as aerosol, at a single dose of 2 units. Fifteen non-treated patients comprised a group of comparison. Eosinophil counts and concentrations of free hemoglobin (by immunometrical method in co-agglutination reaction were made in nasal secretions twice (before treatment and two weeks later. It was found that the increase of free hemoglobin levels, as well as increase in eosinophil count in nasal secretions represents a symptom typical of exacerbation in persistent allergic rhinitis and reflects severity of disease. The therapy led to significant clinical improvement, decrease in free hemoglobin levels and eosinophil counts in nasal secretions, corresponding to clinical effect of both therapeutic modes of topical pharmacotherapy, resp., in 73% and 79% of the patients with persisting allergic rhinitis. Decrease in free hemoglobin level has allowed for the first time to reveal the immunotherapeutic efficiency of treatment with Affinoleukin® aerosol during exacerbations of persisting allergic rhinitis.

  17. Glycosylation of hemoglobin and plasma proteins in petrochemical plant workers

    Energy Technology Data Exchange (ETDEWEB)

    Unrug, A.; Tomaszewski, L.


    The concentration of glycosylated hemoglobin and (plasma) proteins has been measured in 111 workers of 6 MZRiP departments in Plock and in 54 healthy people. In all subjects the mean concentrations of glycosylated hemoglobin and glycosylated plasma proteins have been in so called wide range of normal values. Significant shifts of glycosylated Hb concentrations have been found in two departments--those of ethylenederivatives and distillation. The concentration of glycosylated plasma proteins has been elevated only in workers of the Catalytic Processes Department.

  18. Correlation of serum leptin with levels of hemoglobin in hemodialysis

    Directory of Open Access Journals (Sweden)

    Rafieian-Kopaei Mahmoud


    Full Text Available To examine the association of serum leptin level with anemia in hemodialysis, we investigated 36 patients (males: 21, diabetics: 11 under regular hemodialysis. For patients, complete blood counts, iron profile, serum leptin, and adequacy of hemodialysis were assessed. In this study a significant correlation of serum leptin with level of hemoglobin and body mass index was detected. An association between serum leptin and total iron binding capacity was observed. No correlation of serum ferritin with leptin level was seen. Our findings attest previous findings showing that greater serum leptin levels are associated with greater hemoglobin levels.

  19. Validation of virus inactivation by heat treatment in the manufacture of diaspirin crosslinked hemoglobin. (United States)

    Farmer, M; Ebeling, A; Marshall, T; Hauck, W; Sun, C S; White, E; Long, Z


    Diaspirin crosslinked hemoglobin (DCLHb), a hemoglobin based oxygen carrying solution prepared from outdated human blood, is subjected to a heat treatment step to inactivate viruses in our manufacturing process. To validate the efficacy of this inactivation, we have simulated the heat treatment procedure at a reduced scale using hemoglobin solution spiked with representative viruses. Human Immuno-deficiency Virus (HIV), Cytomegalovirus (CMV), and Duck Hepatitis B Virus (DHBV) were used in this validation. Inoculation with concentrated virus was performed just prior to the heat treatment to determine the effect of that specific process step. Samples were taken before, during, and after heat treatment and assayed for virus titer in an attempt to assess the rate as well as the extent of virus inactivation. CMV was analyzed in a plaque assay using MRC-5 indicator cells. The titer was reduced from 3.3 x 10(6) plaque forming units (PFU) per mL to less than 5 x 10(1) PFU/mL (detection limit) within 30 minutes. DHBV was analyzed by inoculation of serially diluted samples into Pekin ducklings, followed at intervals by screening sera for DHBV DNA by dot blot hybridization. The titer was reduced from 5.0 x 10(6) duck infectious units (DIU) per mL to less than 5 x 10(0) DIU/mL (detection limit) within 1 hour. HIV titers were determined through an ELISA assay for p24 antigen present in peripheral blood lymphocyte cocultivation supernatants. The titer was reduced from 2.0 x 10(4) infectious units (IU) per mL to less than 2 x 10(0) IU/mL (detection limit) within 1 hour. These data indicate that high titers of these blood borne viruses are rapidly inactivated by this heat treatment process.

  20. Characterization of glycidol-hemoglobin adducts as biomarkers of exposure and in vivo dose. (United States)

    Honda, Hiroshi; Törnqvist, Margareta; Nishiyama, Naohiro; Kasamatsu, Toshio


    Hemoglobin adducts have been used as biomarkers of exposure to reactive chemicals. Glycidol, an animal carcinogen, has been reported to form N-(2,3-dihydroxy-propyl)valine adducts to hemoglobin (diHOPrVal). To support the use of these adducts as markers of glycidol exposure, we investigated the kinetics of diHOPrVal formation and its elimination in vitro and in vivo. Five groups of rats were orally administered a single dose of glycidol ranging from 0 to 75mg/kg bw, and diHOPrVal levels were measured 24h after administration. A dose-dependent increase in diHOPrVal levels was observed with high linearity (R(2)=0.943). Blood sampling at different time points (1, 10, 20, or 40days) from four groups administered glycidol at 12mg/kg bw suggested a linear decrease in diHOPrVal levels compatible with the normal turnover of rat erythrocytes (life span, 61days), with the calculated first-order elimination rate constant (kel) indicating that the diHOPrVal adduct was chemically stable. Then, we measured the second-order rate constant (kval) for the reaction of glycidol with N-terminal valine in rat and human hemoglobin in in vitro experiments with whole blood. The kval was 6.7±1.1 and 5.6±1.3 (pmol/g globin per μMh) in rat and human blood, respectively, indicating no species differences. In vivo doses estimated from kval and diHOPrVal levels were in agreement with the area under the (concentration-time) curve values determined in our earlier toxicokinetic study in rats. Our results indicate that diHOPrVal is a useful biomarker for quantification of glycidol exposure and for risk assessment.

  1. Spectrin, human erythrocyte shapes, and mechanochemical properties.


    Stokke, B T; Mikkelsen, A.; Elgsaeter, A


    Physical studies of human erythrocyte spectrin indicate that isolated spectrin dimers and tetramers in solution are worm-like coils with a persistence length of approximately 20 nm. This finding, the known polyelectrolytic nature of spectrin, and other structural information about spectrin and the membrane skeleton molecular organization have lead us to the hypothesis that the human erythrocyte membrane skeleton constitutes a two-dimensional ionic gel (swollen ionic elastomer). This concept i...

  2. Fluorescence Spectra and Enzymatic Property of Hemoglobin as Mimetic Peroxidase

    Institute of Scientific and Technical Information of China (English)

    LiDe-jia; LiHai-cheng; ZouGuo-lin


    Intrinsic fluorescence emission maxima of hemo-lobin(Hb) was investigated in relation to peroxidase property of Hb. The peroxidase activity of Hb was based on its catalytic activity for oxidation of o-phenylenediamine by hydrogen peroxide. Hb was treated in the condition (temperature,ethanol and salt) that tetramer-dimer equilibrium of Hb is shifted to the dimer state and its fluorescence spectrum was measured. When Hb treated in temperature (60-70 ℃), ethanol concentration (60%-70%) and NaCl concentration (2. 5-3.0 mol/L), the fluorescence emission maxima of Hb shifted towards red wavelength and its activity decreased quickly.Experimental results revealed that the activity and stability of Hb as mimetic peroxidase was closely relative to the hydrophobic environment of active center of Hb, and when Hb (FeⅡ) converted into met Hb (FeⅢ ), its activity was 1. 6 times as much as that of Hb.

  3. A hemoglobin A1C immunoassay method not affected by carbamylated hemoglobin. (United States)

    Rose, A M; Tongate, C; Valdes, R


    Hemoglobin A1C (HbA1C) methods based on charge separation of Hb species are subject to interference from carbamylated Hb (carb Hb). Carb Hb adducts are formed via interaction of terminal amino groups of HbA with isocyanic acid, after the spontaneous dissociation of urea to cyanate. It is hypothesized that a new immunoassay method, using a monoclonal antibody that recognizes the N-terminus of the Hb beta-chain and its sugar moiety, should be refractory to cross-reactive interference from carb Hb. To test this hypothesis, Hb was carbamylated in vitro and co-migration of carb Hb assessed with HbA1C using an electrophoretic method. Densitometric scans - post sodium cyanate incubation and electrophoretic separation - showed a 5 to 7 fold elevation of the HbA1C peak only, while HbA1C values obtained using immunoassay were unaffected. Also assessed was carbamylation interference in vivo, and a positive proportional bias with the electrophoretic system (Y) was observed compared to the immunoassay system (X) (y = 1.2x - 0.21 percent). Others have shown that carb Hb may cause a clinically significant false elevation in patient HbA1C values, when methods based on charge separation of Hb species are used. It is our conclusion, however, that while carb Hb may play a role, the differences observed in this study are largely due to calibration.

  4. Modulation of oxygen binding to insect hemoglobins: the structure of hemoglobin from the botfly Gasterophilus intestinalis. (United States)

    Pesce, Alessandra; Nardini, Marco; Dewilde, Sylvia; Hoogewijs, David; Ascenzi, Paolo; Moens, Luc; Bolognesi, Martino


    Hemoglobins (Hbs) reversibly bind gaseous diatomic ligands (e.g., O2) as the sixth heme axial ligand of the penta-coordinate deoxygenated form. Selected members of the Hb superfamily, however, display a functionally relevant hexa-coordinate heme Fe atom in their deoxygenated state. Endogenous heme hexa-coordination is generally provided in these Hbs by the E7 residue (often His), which thus modulates accessibility to the heme distal pocket and reactivity of the heme toward exogenous ligands. Such a pivotal role of the E7 residue is prominently shown by analysis of the functional and structural properties of insect Hbs. Here, we report the 2.6 A crystal structure of oxygenated Gasterophilus intestinalis Hb1, a Hb known to display a penta-coordinate heme in the deoxygenated form. The structure is analyzed in comparison with those of Drosophila melanogaster Hb, exhibiting a hexa-coordinate heme in its deoxygenated derivative, and of Chironomus thummi thummi HbIII, which displays a penta-coordinate heme in the deoxygenated form. Despite evident structural differences in the heme distal pockets, the distinct molecular mechanisms regulating O2 binding to the three insect Hbs result in similar O(2 affinities (P50 values ranging between 0.12 torr and 0.46 torr).

  5. Relationship between maternal hemoglobin concentration and neonatal birth weight. (United States)

    Sekhavat, Leila; Davar, Robab; Hosseinidezoki, Somaiasadat


    Pregnancy considerably increases iron needs in a mother and her fetus. The purpose of this study was to assess the relationship between maternal hemoglobin concentration in labor with neonatal birth weight. A population-based study in Shahid Sadughi Hospital in Yazd, Iran, was performed by comparing 1842 singleton term pregnancies of patients with and without anemia and their newborns. Maternal characteristics, including hemoglobin values, were recorded at the labor visit. Maternal anemia was defined as hemoglobin concentration lower than 10 g/dl during pregnancy. Main outcome measures included birth weight and Apgar score. Linear and logistic regression models were used to analyze data. Anemia (Hb 13 g/dl) increased the risk of low birth weight but it was not significant. The risk of a low Apgar score was significantly increased in women with anemia. The minimum incidence of low birth weight occurs in association with a hemoglobin concentration of 10-13 g/dl. Maternal anemia was significantly associated with effect on birth weight. Also Hb > 13 g/dl was also associated with an increased risk of low birth weight.

  6. Prediction models for hemoglobin deferral in whole blood donors

    NARCIS (Netherlands)

    Baart, A.M.


    Each year, a relevant proportion of the invited blood donors is eventually deferred from donation because of low hemoglobin (Hb) levels. Deferrals are meant to protect donors from developing iron deficiency anemia after a blood donation, however, they may increase the risk of donor lapse, even thoug

  7. Effect of some high consumption spices on hemoglobin glycation

    Directory of Open Access Journals (Sweden)

    G H Naderi


    Full Text Available Formation of glycation products is major factor responsible in complications of diabetes. Worldwide trend is toward the use of natural additives in reducing the complications of diseases. Therefore, there is a growing interest in natural antiglycation found in plants. Herbs and spices are one of the most important targets to search for natural antiglycation from the point of view of safety. This study investigated the ability of some of the spices to inhibit glycation process in a hemoglobin/glucose model system and compared their potency with each other. For this subject the best concentration and time to incubate glucose with hemoglobin was investigated. Then the glycosylation degree of hemoglobin in the presence of extracts by the three concentrations 0.25, 0.5 and 1 μg/ml was measured colorimetrically at 520 nm. Results represent that some of extracts such as wild caraway, turmeric, cardamom and black pepper have inhibitory effects on hemoglobin glycation. But some of the extracts such as anise and saffron have not only inhibitory effects but also aggravated this event and have proglycation properties. In accordance with the results obtained we can conclude that wild caraway, turmeric, cardamom and black pepper especially wild caraway extracts are potent antiglycation agents, which can be of great value in the preventive glycation-associated complications in diabetes.

  8. Effect of some high consumption spices on hemoglobin glycation. (United States)

    Naderi, G H; Dinani, Narges J; Asgary, S; Taher, M; Nikkhoo, N; Boshtam, M


    Formation of glycation products is major factor responsible in complications of diabetes. Worldwide trend is toward the use of natural additives in reducing the complications of diseases. Therefore, there is a growing interest in natural antiglycation found in plants. Herbs and spices are one of the most important targets to search for natural antiglycation from the point of view of safety. This study investigated the ability of some of the spices to inhibit glycation process in a hemoglobin/glucose model system and compared their potency with each other. For this subject the best concentration and time to incubate glucose with hemoglobin was investigated. Then the glycosylation degree of hemoglobin in the presence of extracts by the three concentrations 0.25, 0.5 and 1 μg/ml was measured colorimetrically at 520 nm. Results represent that some of extracts such as wild caraway, turmeric, cardamom and black pepper have inhibitory effects on hemoglobin glycation. But some of the extracts such as anise and saffron have not only inhibitory effects but also aggravated this event and have proglycation properties. In accordance with the results obtained we can conclude that wild caraway, turmeric, cardamom and black pepper especially wild caraway extracts are potent antiglycation agents, which can be of great value in the preventive glycation-associated complications in diabetes.

  9. The Relationship Between Hemoglobin Level and Intellectual Function. (United States)

    Munro, Nancy

    In a study to learn whether or not poor nutrition, as indicated by low hemoglobin levels, affects intelligence and behavior, 113 Head Start children in Missoula, Montana took part. Group testing with the Lorge Thorndike Intelligence Test and individual testing with the Wechsler and Primary Scale of Intelligence or Wechsler Intelligence Scale for…

  10. Ultrasonic processing for recovery of chicken erythrocyte hemoglobin (United States)

    Hemoglobin from chicken blood has been shown to be a good substitute for synthetic polymeric flocculants. One stage of processing the blood entails breaking open the cells and releasing the cytoplasmic contents; in the present study, we investigate the use of ultrasonic processing at this stage. Was...

  11. Myth or reality : Hematocrit and hemoglobin differ in trauma

    NARCIS (Netherlands)

    Nijboer, Johanna M. M.; van der Horst, Iwan C. C.; Hendriks, Herman G. D.; ten Duis, Hendrik-Jan; Nijsten, Maarten W. N.


    Background: Estimating blood loss in trauma patients usually involves the determination of hematocrit (Ht) or hemoglobin (Hb). However, in trauma patients, a poorly substantiated habit exists to determine both Ht and Hb in assessing acute blood loss. This suggests that Ht and Hb provide different in

  12. Hemoglobin, Growth, and Attention of Infants in Southern Ethiopia (United States)

    Aubuchon-Endsley, Nicki L.; Grant, Stephanie L.; Berhanu, Getenesh; Thomas, David G.; Schrader, Sarah E.; Eldridge, Devon; Kennedy, Tay; Hambidge, Michael


    Male and female infants from rural Ethiopia were tested to investigate relations among hemoglobin (Hb), anthropometry, and attention. A longitudinal design was used to examine differences in attention performance from 6 (M = 24.9 weeks, n = 89) to 9 months of age (M = 40.6 weeks, n = 85), differences hypothesized to be related to changes in iron…

  13. Glycated Hemoglobin Measurement and Prediction of Cardiovascular Disease

    NARCIS (Netherlands)

    Di Angelantonio, Emanuele; Gao, Pei; Khan, Hassan; Butterworth, Adam S.; Wormser, David; Kaptoge, Stephen; Seshasai, Sreenivasa Rao Kondapally; Thompson, Alex; Sarwar, Nadeem; Willeit, Peter; Ridker, Paul M.; Barr, Elizabeth L. M.; Khaw, Kay-Tee; Psaty, Bruce M.; Brenner, Hermann; Balkau, Beverley; Dekker, Jacqueline M.; Lawlor, Debbie A.; Daimon, Makoto; Willeit, Johann; Njolstad, Inger; Nissinen, Aulikki; Brunner, Eric J.; Kuller, Lewis H.; Price, Jackie F.; Sundstrom, Johan; Knuiman, Matthew W.; Feskens, Edith J. M.; Verschuren, W. M. M.; Wald, Nicholas; Bakker, Stephan J. L.; Whincup, Peter H.; Ford, Ian; Goldbourt, Uri; Gomez-de-la-Camara, Agustin; Gallacher, John; Simons, Leon A.; Rosengren, Annika; Sutherland, Susan E.; Bjorkelund, Cecilia; Blazer, Dan G.; Wassertheil-Smoller, Sylvia; Onat, Altan; Ibanez, Alejandro Marin; Casiglia, Edoardo; Jukema, J. Wouter; Simpson, Lara M.; Giampaoli, Simona; Nordestgaard, Borge G.; Selmer, Randi; Wennberg, Patrik; Kauhanen, Jussi; Salonen, Jukka T.; Dankner, Rachel; Barrett-Connor, Elizabeth; Kavousi, Maryam; Gudnason, Vilmundur; Evans, Denis; Wallace, Robert B.; Cushman, Mary; D'Agostino, Ralph B.; Umans, Jason G.; Kiyohara, Yutaka; Nakagawa, Hidaeki; Sato, Shinichi; Gillum, Richard F.; Folsom, Aaron R.; van der Schouw, Yvonne T.; Moons, Karel G.; Griffin, Simon J.; Sattar, Naveed; Wareham, Nicholas J.; Selvin, Elizabeth; Thompson, Simon G.; Danesh, John


    IMPORTANCE The value of measuring levels of glycated hemoglobin (HbA(1c)) for the prediction of first cardiovascular events is uncertain. OBJECTIVE To determine whether adding information on HbA(1c) values to conventional cardiovascular risk factors is associated with improvement in prediction of ca

  14. Membrane alterations in irreversibly sickled cells: hemoglobin--membrane interaction. (United States)

    Lessin, L S; Kurantsin-Mills, J; Wallas, C; Weems, H


    Irreversibly sickled cells (ISCs) are sickle erythrocytes which retain bipolar elongated shapes despite reoxygenation and owe their biophysical abnormalities to acquired membrane alterations. Freeze-etched membranes both of ISCs produced in vitro and ISCs isolated in vivo reveal microbodies fixed to the internal (PS) surface which obscure spectrin filaments. Intramembranous particles (IMPs) on the intramembrane (PF) surface aggregate over regions of subsurface microbodies. Electron microscopy of diaminobenzidine-treated of ISC ghosts show the microbodies to contain hemoglobin and/or hemoglobin derivatives. Scanning electron microscopy and freeze-etching demonstrate that membrane--hemoglobin S interaction in ISCs enhances the membrane loss by microspherulation. Membrane-bound hemoglobin is five times greater in in vivo ISCs than non-ISCs, and increases during ISC production, parallelling depletion of adenosine triphosphate. Polyacrylamide gel electrophoresis of ISC membranes shows the presence of high-molecular-weight heteropolymers in the pre--band 1 region, a decrease in band 4.1 and an increase in bands 7, 8, and globin. The role of cross-linked membrane protein polymers in the generation of ISCs is discussed and is synthesized in terms of a unified concept for the determinants of the genesis of ISCs.

  15. Postnatal Prediction of Gestational Age Using Newborn Fetal Hemoglobin Levels

    Directory of Open Access Journals (Sweden)

    Kumanan Wilson


    Discussion: The development of a point-of-care mechanism to allow widespread implementation of postnatal gestational age prediction tools that make use of hemoglobin or non-mass spectromietry-derived metabolites could serve areas where antenatal gestational age dating is not routinely available.

  16. Importance of hemoglobin concentration to exercise: acute manipulations

    DEFF Research Database (Denmark)

    Calbet, José A L; Lundby, Carsten; Koskolou, Maria


    An acute reduction of blood hemoglobin concentration ([Hb]), even when the circulating blood volume is maintained, results in lower (.)V(O(2)(max) and endurance performance, due to the reduction of the oxygen carrying capacity of blood. Conversely, an increase of [Hb] is associated with enhanced...

  17. Effect of periodontal therapy on hemoglobin and erythrocyte levels in chronic generalized periodontitis patients: An interventional study

    Directory of Open Access Journals (Sweden)

    Agarwal Nupur


    Full Text Available Aims and Objectives : Anemia of chronic disease (ACD is one of the most common forms of anemia. It is defined as anemia occurring in chronic infections, inflammatory conditions or neoplastic disorders which are not due to marrow deficiencies or other diseases, and occurring despite the presence of adequate iron stores and vitamins. Periodontitis is one of the most prevalent chronic inflammatory diseases in humans. This study aimed at finding out if periodontitis, like other inflammatory conditions, could lead to anemia. Materials and Methods : Thirty chronic generalized periodontitis male patients with hemoglobin levels below 15 mg/dl and serum ferritin values above 30 ng/ml were selected. The various blood parameters recorded at baseline were hemoglobin levels(Hb, erythrocyte count (RBC, erythrocyte sedimentation rate (ESR, mean corpuscular volume(MCV, mean corpuscular hemoglobin (MCH and mean corpuscular hemoglobin concentration (MCHC. Periodontal parameters recorded at baseline included: plaque index, gingival index, probing pocket depth, clinical attachment level. Periodontal treatment including surgery if required was carried out in all the patients. Periodontal status of patients was monitored by repeating evaluation of periodontal indices at three months and at the end of one year. The hematological values were again measured at the end of one year. Results: The results showed that correction of periodontal inflammation resulted in a significant increase in hemoglobin levels and erythrocyte counts. The erythrocyte sedimentation rate showed a reduction indicating resolution of periodontal inflammation. There was a significant, but much lesser, improvement in MCV, MCH and MCHC values. Conclusion: The results of this study showed that treatment of periodontitis leads to an improvement in hematocrit and other related blood parameters in chronic generalized periodontitis patients with anemia. This provides evidence that periodontitis like

  18. Characterization of glycidol-hemoglobin adducts as biomarkers of exposure and in vivo dose

    Energy Technology Data Exchange (ETDEWEB)

    Honda, Hiroshi, E-mail: [R and D Safety Science Research, Kao Corporation, 2606 Akabane, Ichikai-Machi, Haga-Gun, Tochigi 321-3497 (Japan); Törnqvist, Margareta [Department of Materials and Environmental Chemistry, Environmental Chemistry Unit, Stockholm University, SE-106 91 Stockholm (Sweden); Nishiyama, Naohiro [R and D Safety Science Research, Kao Corporation, 2606 Akabane, Ichikai-Machi, Haga-Gun, Tochigi 321-3497 (Japan); Kasamatsu, Toshio, E-mail: [R and D Safety Science Research, Kao Corporation, 2606 Akabane, Ichikai-Machi, Haga-Gun, Tochigi 321-3497 (Japan)


    Hemoglobin adducts have been used as biomarkers of exposure to reactive chemicals. Glycidol, an animal carcinogen, has been reported to form N-(2,3-dihydroxy-propyl)valine adducts to hemoglobin (diHOPrVal). To support the use of these adducts as markers of glycidol exposure, we investigated the kinetics of diHOPrVal formation and its elimination in vitro and in vivo. Five groups of rats were orally administered a single dose of glycidol ranging from 0 to 75 mg/kg bw, and diHOPrVal levels were measured 24 h after administration. A dose-dependent increase in diHOPrVal levels was observed with high linearity (R{sup 2} = 0.943). Blood sampling at different time points (1, 10, 20, or 40 days) from four groups administered glycidol at 12 mg/kg bw suggested a linear decrease in diHOPrVal levels compatible with the normal turnover of rat erythrocytes (life span, 61 days), with the calculated first-order elimination rate constant (k{sub el}) indicating that the diHOPrVal adduct was chemically stable. Then, we measured the second-order rate constant (k{sub val}) for the reaction of glycidol with N-terminal valine in rat and human hemoglobin in in vitro experiments with whole blood. The k{sub val} was 6.7 ± 1.1 and 5.6 ± 1.3 (pmol/g globin per μMh) in rat and human blood, respectively, indicating no species differences. In vivo doses estimated from k{sub val} and diHOPrVal levels were in agreement with the area under the (concentration–time) curve values determined in our earlier toxicokinetic study in rats. Our results indicate that diHOPrVal is a useful biomarker for quantification of glycidol exposure and for risk assessment. - Highlight: • Glycidol-hemoglobin adduct (diHOPrVal) was characterized for exposure evaluation. • We studied the kinetics of diHOPrVal formation and elimination in vitro and in vivo. • Dose dependent formation and chemical stability were confirmed in the rat study. • In vivo dose (AUC) of glycidol could be estimated from diHOPrVal levels

  19. Fasting serum glucose and glycosylated hemoglobin level in obesity. (United States)

    Das, R K; Nessa, A; Hossain, M A; Siddiqui, N I; Hussain, M A


    Obesity is a condition in which the body fat stores are increased to an extent which impairs health and leads to serious health consequences. The amount of body fat is difficult to measure directly, and is usually determined from an indirect measure - the body mass index (BMI). Increased BMI in obese persons is directly associated with an increase in metabolic disease, such as type 2 diabetes mellitus. This Analytical cross sectional study was undertaken to assess the relation between obesity and glycemic control of body by measuring fasting serum glucose and glycosylated hemoglobin. This study was carried out in the Department of Physiology, Mymensingh Medical College, Mymensingh from 1st July 2011 to 30th June 2012 on 120 equally divided male and female persons within the age range of 25 to 55 years. Age more than 55 years and less than 25 years and diagnosed case of Hypothyroidism, Cushing's syndrome, polycystic ovary, Antipsychotic drug user and regular steroid users were excluded. Non probability purposive type of sampling technique was used for selecting the study subjects. Measurement of body mass index was done as per procedure. Fasting serum glucose was estimated by glucose oxidase method and Glycosylated hemoglobin by Boronate Affinity method. Statistical analysis was done by SPSS (version 17.0). Data were expressed as Mean±SE and statistical significance of difference among the groups were calculated by unpaired student's 't' test and Pearson's correlation coefficient tests were done as applicable. The Mean±SE of fasting serum glucose was significant at 1% level (P value glycosylated hemoglobin level between control and study groups. But there was positive correlation within each group. Fasting serum glucose also showed a bit stronger positive correlation with BMI. Both obese male and female persons showed higher levels of fasting serum glucose and glycosylated hemoglobin. The observed positive correlation between BMI with fasting serum glucose and

  20. Hemoglobin Kinetics and Long-term Prognosis in Heart Failure. (United States)

    Díez-López, Carles; Lupón, Josep; de Antonio, Marta; Zamora, Elisabet; Domingo, Mar; Santesmases, Javier; Troya, Maria-Isabel; Boldó, Maria; Bayes-Genis, Antoni


    The influence of hemoglobin kinetics on outcomes in heart failure has been incompletely established. Hemoglobin was determined at the first visit and at 6 months. Anemia was defined according to World Health Organization criteria (hemoglobin < 13g/dL for men and hemoglobin < 12g/dL for women). Patients were classified relative to their hemoglobin values as nonanemic (both measurements normal), transiently anemic (anemic at the first visit but not at 6 months), newly anemic (nonanemic initially but anemic at 6 months), or permanently anemic (anemic in both measurements). A total of 1173 consecutive patients (71.9% men, mean age 66.8±12.2 years) were included in the study. In all, 476 patients (40.6%) were considered nonanemic, 170 (14.5%) had transient anemia, 147 (12.5%) developed new-onset anemia, and 380 (32.4%) were persistently anemic. During a follow-up of 3.7±2.8 years after the 6-month visit, 494 patients died. On comprehensive multivariable analyses, anemia (P < .001) and the type of anemia (P < .001) remained as independent predictors of all-cause mortality. Compared with patients without anemia, patients with persistent anemia (hazard ratio [HR] = 1.62; 95% confidence interval [95%CI], 1.30-2.03; P < .001) and new-onset anemia (HR = 1.39; 95%CI, 1.04-1.87, P = .03) had higher mortality, and even transient anemia showed a similar trend, although without reaching statistical significance (HR = 1.31; 95%CI, 0.97-1.77, P = .075). Anemia, especially persistent and of new-onset, and to a lesser degree, transient anemia, is deleterious in heart failure. Copyright © 2016 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  1. Molecular dynamics insights into human aquaporin 2 water channel. (United States)

    Binesh, A R; Kamali, R


    In this study, the first molecular dynamics simulation of the human aquaporin 2 is performed and for a better understanding of the aquaporin 2 permeability performance, the characteristics of water transport in this protein channel and key biophysical parameters of AQP2 tetramer including osmotic and diffusive permeability constants and the pore radius are investigated. For this purpose, recently recovered high resolution X-ray crystal structure of` the human aquaporin 2 is used to perform twenty nanosecond molecular dynamics simulation of fully hydrated tetramer of this protein embedded in a lipid bilayer. The resulting water permeability characteristics of this protein channel showed that the water permeability of the human AQP2 is in a mean range in comparison with other human aquaporins family. Finally, the results reported in this research demonstrate that molecular dynamics simulation of human AQP2 provided useful insights into the mechanisms of water permeation and urine concentration in the human kidney.

  2. Genetic hemoglobin disorders rather than iron deficiency are a major predictor of hemoglobin concentration in women of reproductive age in rural prey Veng, Cambodia. (United States)

    Karakochuk, Crystal D; Whitfield, Kyly C; Barr, Susan I; Lamers, Yvonne; Devlin, Angela M; Vercauteren, Suzanne M; Kroeun, Hou; Talukder, Aminuzzaman; McLean, Judy; Green, Timothy J


    Anemia is common in Cambodian women. Potential causes include micronutrient deficiencies, genetic hemoglobin disorders, inflammation, and disease. We aimed to investigate factors associated with anemia (low hemoglobin concentration) in rural Cambodian women (18-45 y) and to investigate the relations between hemoglobin disorders and other iron biomarkers. Blood samples were obtained from 450 women. A complete blood count was conducted, and serum and plasma were analyzed for ferritin, soluble transferrin receptor (sTfR), folate, vitamin B-12, retinol binding protein (RBP), C-reactive protein (CRP), and α1 acid glycoprotein (AGP). Hemoglobin electrophoresis and multiplex polymerase chain reaction were used to determine the prevalence and type of genetic hemoglobin disorders. Overall, 54% of women had a genetic hemoglobin disorder, which included 25 different genotypes (most commonly, hemoglobin E variants and α(3.7)-thalassemia). Of the 420 nonpregnant women, 29.5% had anemia (hemoglobin iron stores (ferritin iron deficiency (sTfR >8.3 mg/L), iron deficiency anemia (IDA) were 14.2% and 1.5% in those with and without hemoglobin disorders, respectively. There was no biochemical evidence of vitamin A deficiency (RBP 5 mg/L) and 26% (AGP >1 g/L) of nonpregnant women, respectively. By using an adjusted linear regression model, the strongest predictors of hemoglobin concentration were hemoglobin E homozygous disorder and pregnancy status. Other predictors were 2 other heterozygous traits (hemoglobin E and Constant Spring), parity, RBP, log ferritin, and vitamin B-12. Multiple biomarkers for anemia and iron deficiency were significantly influenced by the presence of hemoglobin disorders, hence reducing their diagnostic sensitivity. Further investigation of the unexpectedly low prevalence of IDA in Cambodian women is warranted. © 2015 American Society for Nutrition.

  3. Phenotypic expression of hemoglobins A₂, E and F in various hemoglobin E related disorders. (United States)

    Sae-ung, Nattaya; Srivorakun, Hataichanok; Fucharoen, Goonnapa; Yamsri, Supawadee; Sanchaisuriya, Kanokwan; Fucharoen, Supan


    Study on the phenotypic expression of hemoglobin (Hb) A(2) and Hb E in Hb E disorders has been difficult due to the co-separation of Hb A(2) and Hb E in most Hb analysis assays. Because these two Hbs are separated on capillary electrophoresis, we studied phenotypic expression of Hbs A(2), E and F in various Hb E disorders using this system. This was done on 362 subjects with several Hb E disorders including heterozygous Hb E, homozygous Hb E, β-thalassemia/Hb E, δβ-thalassemia/Hb E, and Hb Lepore/Hb E and those of these disorders with several forms of α-thalassemia. Normal controls showed Hb A(2) of 2.7 ± 0.3%. Heterozygous Hb E and homozygous Hb E had elevated Hb A(2) i.e. 3.8 ± 0.3% and 4.8 ± 0.5%, respectively. Further elevations were observed for β(0)-thalassemia/Hb E (6.1 ± 1.9%) and β(+)-thalassemia/Hb E (7.1 ± 1.2%). Interestingly, no elevation of Hb A(2) was found in the δβ-thalassemia/Hb E, and Hb Lepore/Hb E (2.3 ± 0.3%) but higher Hb F levels were noted which could be useful diagnostic markers. The levels of Hb E were variable. Co-inheritance of these Hb E disorders with α-thalassemia were associated with lower outputs of Hb E and Hb F but the levels of Hb A(2) were not altered. Different phenotypic expression of Hb A(2), Hb E and Hb F could help in differential diagnosis of these Hb E related disorders commonly encountered in the regions where access to molecular techniques is limited.

  4. Amino acid efflux by asexual blood-stage Plasmodium falciparum and its utility in interrogating the kinetics of hemoglobin endocytosis and catabolism in vivo. (United States)

    Dalal, Seema; Klemba, Michael


    The endocytosis and catabolism of large quantities of host cell hemoglobin is a hallmark of the intraerythrocytic asexual stage of the human malaria parasite Plasmodium falciparum. It is known that the parasite's production of amino acids from hemoglobin far exceeds its metabolic needs. Here, we show that P. falciparum effluxes large quantities of certain non-polar (Ala, Leu, Val, Pro, Phe, Gly) and polar (Ser, Thr, His) amino acids to the external medium. That these amino acids originate from hemoglobin catabolism is indicated by the strong correlation between individual amino acid efflux rates and their abundances in hemoglobin, and the ability of the food vacuole falcipain inhibitor E-64d to greatly suppress efflux rates. We then developed a rapid, sensitive and precise method for quantifying flux through the hemoglobin endocytic-catabolic pathway that is based on leucine efflux. Optimization of the method involved the generation of a novel amino acid-restricted RPMI formulation as well as the validation of D-norvaline as an internal standard. The utility of this method was demonstrated by characterizing the effects of the phosphatidylinositol-3-kinase inhibitors wortmannin and dihydroartemisinin on the kinetics of Leu efflux. Both compounds rapidly inhibited Leu efflux, which is consistent with a role for phosphtidylinositol-3-phosphate production in the delivery of hemoglobin to the food vacuole; however, wortmannin inhibition was transient, which was likely due to the instability of this compound in culture medium. The simplicity, convenience and non-invasive nature of the Leu efflux assay described here makes it ideal for characterizing the in vivo kinetics of hemoglobin endocytosis and catabolism, for inhibitor target validation studies, and for medium-throughput screens to identify novel inhibitors of cytostomal endocytosis.

  5. Effects of polymerization on the oxygen carrying and redox properties of diaspirin cross-linked hemoglobin. (United States)

    Rogers, M S; Ryan, B B; Cashon, R E; Alayash, A I


    Human hemoglobin site specifically cross-linked with bis(3,5-dibromosalicyl)fumarate results in a low oxygen affinity hemoglobin-based red cell substitute (alpha-DBBF). Polymerization of alpha-DBBF by bis(maleoylglycylamide) polyethylene glycol (BMAA-PEG) yields poly alpha-DBBF which offers the added benefits of reduced renal clearance and increased retention in the vascular circulation. Oxygen equilibrium curves for poly alpha-DBBF are slightly left-shifted (higher O2 affinity) compared to those of alpha-DBBF; with a diminished cooperativity and a reduced Bohr effect. In rapid mixing experiments (oxygen dissociation and carbon monoxide binding), poly alpha-DBBF exhibits a several fold increase in the overall rate of deoxygenation and carbon monoxide binding kinetics over its cross-linked counterpart. The rate of nitric oxide binding to the oxidized form of poly alpha-DBBF shows little or no change compared to the intramolecularly cross-linked derivative. The reduction of cyanomet poly alpha-DBBF by dithionite is several fold faster than that of HbA0 and alpha-DBBF whereas the slow subsequent cyanide dissociation from the ferrous iron remained unchanged among all proteins. The propensity of poly alpha-DBBF for auto-oxidation is slightly enhanced over alpha-DBBF whereas the extent of oxidative modification by hydrogen peroxide is very similar. Polymerization appears to selectively modify ligand interactions and redox kinetics of the tetrameric cross-linked form which reflects a possibly more open heme pocket. The data suggests that changes in oxygenation properties of hemoglobin brought about by a given modification are not necessarily predictive of other functional changes.

  6. Reaction of dehydropyrrolizidine alkaloids with valine and hemoglobin. (United States)

    Zhao, Yuewei; Wang, Shuguang; Xia, Qingsu; Gamboa da Costa, Gonçalo; Doerge, Daniel R; Cai, Lining; Fu, Peter P


    Pyrrolizidine alkaloid-containing plants are probably the most common poisonous plants affecting livestock, wildlife, and humans. Pyrrolizidine alkaloids exert toxicity through metabolism to dehydropyrrolizidine alkaloids that bind to cellular protein and DNA, leading to hepatotoxicity, genotoxicity, and tumorigenicity. To date, it is not clear how dehydropyrrolizidine alkaloids bind to cellular constituents, including amino acids and proteins, resulting in toxicity. Metabolism of carcinogenic monocrotaline, riddelliine, and heliotrine produces dehydromonocrotaline, dehyroriddelliine, and dehydroheliotrine, respectively, as primary reactive metabolites. In this study, we report that reaction of dehydromonocrotaline with valine generated four highly unstable 6,7-dihydro-7-hydroxy-1-hydroxymethyl-5H-pyrrolizine (DHP)-derived valine (DHP-valine) adducts. For structural elucidation, DHP-valine adducts were derivatized with phenyl isothiocyanate (PITC) to DHP-valine-PITC products. After HPLC separation, their structures were characterized by mass spectrometry, UV-visible spectrophotometry, (1)H NMR, and (1)H-(1)H COSY NMR spectral analysis. Two DHP-valine-PITC adducts, designated as DHP-valine-PITC-1 and DHP-valine-PITC-3, had the amino group of valine linked to the C7 position of the necine base, and the other two DHP-valine-PITC products, DHP-valine-PITC-2 and DHP-valine-PITC-4, linked to the C9 position of the necine base. DHP-valine-PITC-1 was interconvertible with DHP-valine-PITC-3, and DHP-valine-PITC-2 was interconvertible with DHP-valine-PITC-4. Reaction of dehydroriddelliine and dehydroheliotrine with valine provided similar results. However, reaction of valine and dehydroretronecine (DHR) under similar experimental conditions did not produce DHP-valine adducts. Reaction of dehydromonocrotaline with rat hemoglobin followed by derivatization with PITC also generated the same four DHP-valine-PITC adducts. This represents the first full structural elucidation of

  7. A hydrodynamic analysis of APOBEC3G reveals a monomer-dimer-tetramer self-association that has implications for anti-HIV function. (United States)

    Salter, Jason D; Krucinska, Jolanta; Raina, Jay; Smith, Harold C; Wedekind, Joseph E


    The innate antiviral factor APOBEC3G (A3G) possesses RNA binding activity and deaminates HIV-1 DNA. High-molecular mass forms of A3G can be isolated from a variety of cell types but exhibit limited deaminase activity relative to low-molecular mass species prepared under RNA-depleted conditions. To investigate the fundamental oligomeric state and shape of A3G, we conducted sedimentation velocity analyses of the pure enzyme under RNA-deficient conditions. The results reveal a predominant dimer in equilibrium with minor monomeric and tetrameric species. Hydrodynamic modeling of the dimer supports an extended cylindrical shape that assembles into an elongated tetramer. Overall, the results provide physical restraints for the A3G quaternary structure that have implications for modulating antiviral function.

  8. Structure of the p53 C-terminus bound to 14-3-3: implications for stabilization of the p53 tetramer. (United States)

    Schumacher, Benjamin; Mondry, Justine; Thiel, Philipp; Weyand, Michael; Ottmann, Christian


    The adaptor protein 14-3-3 binds to and stabilizes the tumor suppressor p53 and enhances its anti-tumour activity. In the regulatory C-terminal domain of p53 several 14-3-3 binding motifs have been identified. Here, we report the crystal structure of the extreme C-terminus (residues 385-393, p53pT387) of p53 in complex with 14-3-3sigma at a resolution of 1.28A. p53pT387 is accommodated by 14-3-3 in a yet unrecognized fashion implying a rationale for 14-3-3 binding to the active p53 tetramer. The structure exhibits a potential binding site for small molecules that could stabilize the p53/14-3-3 protein complex suggesting the possibility for therapeutic intervention. Copyright 2010 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  9. Determination of spirocyclic tetronic/tetramic acid derivatives and neonicotinoid insecticides in fruits and vegetables by liquid chromatography and mass spectrometry after dispersive liquid-liquid microextraction. (United States)

    Pastor-Belda, Marta; Garrido, Isabel; Campillo, Natalia; Viñas, Pilar; Hellín, Pilar; Flores, Pilar; Fenoll, José


    Dispersive liquid-liquid microextraction was used to preconcentrate three spirocyclic tetronic/tetramic acid derivatives (spirotetramat, spiromesifen and spirodiclofen) and five neonicotinoid (thiamethoxam, chlotianidin, imidacloprid, acetamiprid and thiacloprid) insecticides previously extracted from fruit and vegetable matrices with acetonitrile. The organic enriched phase was evaporated, reconstituted in 25μL acetonitrile and analyzed by reversed-phase liquid chromatography with tandem mass spectrometry using a triple quadrupole in selected reaction monitoring mode. Enrichment factors in the 15-100 range were obtained. A matrix effect was observed, the detection limits varying between 0.025 and 0.5ngg(-1), depending on the compound and the sample matrix. The developed method was applied to the analysis of 25 samples corresponding to five different fruit and vegetable matrices. Only thiamethoxam was detected in a lemon sample at a concentration close to the quantification limit, and spiromesifen and spirotetramat at concentrations between 11.6 and 54.5ngg(-1).

  10. Kaposi's Sarcoma-Associated Herpesvirus Rta Tetramers Make High-Affinity Interactions with Repetitive DNA Elements in the Mta Promoter To Stimulate DNA Binding of RBP-Jk/CSL ▿ † (United States)

    Palmeri, Diana; Carroll, Kyla Driscoll; Gonzalez-Lopez, Olga; Lukac, David M.


    Kaposi's sarcoma-associated herpesvirus (KSHV; also known as human herpesvirus 8 [HHV-8]) is the etiologic agent of Kaposi's sarcoma (KS) and lymphoproliferative diseases. We previously demonstrated that the KSHV lytic switch protein Rta stimulates DNA binding of the cellular RBP-Jk/CSL protein, the nuclear component of the Notch pathway, on Rta target promoters. In the current study, we define the promoter requirements for formation of transcriptionally productive Rta/RBP-Jk/DNA complexes. We show that highly pure Rta footprints 7 copies of a previously undescribed repetitive element in the promoter of the essential KSHV Mta gene. We have termed this element the “CANT repeat.” CANT repeats are found on both strands of DNA and have a consensus sequence of ANTGTAACANT(A/T)(A/T)T. We demonstrate that Rta tetramers make high-affinity interactions (i.e., nM) with 64 bp of the Mta promoter but not single CANT units. The number of CANT repeats, their presence in palindromes, and their positions relative to the RBP-Jk binding site determine the optimal target for Rta stimulation of RBP-Jk DNA binding and formation of ternary Rta/RBP-Jk/DNA complexes. DNA binding and tetramerization mutants of Rta fail to stimulate RBP-Jk DNA binding. Our chromatin immunoprecipitation assays show that RBP-Jk DNA binding is broadly, but selectively, stimulated across the entire KSHV genome during reactivation. We propose a model in which tetramerization of Rta allows it to straddle RBP-Jk and contact repeat units on both sides of RBP-Jk. Our study integrates high-affinity Rta DNA binding with the requirement for a cellular transcription factor in Rta transactivation. PMID:21880753

  11. Two-dimensional analysis of glycated hemoglobin heterogeneity in pediatric type 1 diabetes patients. (United States)

    Hempe, James M; McGehee, Amanda M; Chalew, Stuart A


    Interindividual and ethnic variation in glycated hemoglobin levels, unrelated to blood glucose variation, complicates the clinical use of glycated hemoglobin assays for the diagnosis and management of diabetes. Assessing the types and amounts of glycated hemoglobins present in erythrocytes could provide insight into the mechanism. Blood samples and self-monitored mean blood glucose (MBG) levels were obtained from 85 pediatric type 1 diabetes patients. Glycated hemoglobin levels were measured using three primary assays (boronate-affinity chromatography, capillary isoelectric focusing (CIEF), and standardized DCA2000+ immunoassay) and a two-dimensional (2D) analytical system consisting of boronate-affinity chromatography followed by CIEF. The 2D system separated hemoglobin into five subfractions, four of which contained glycated hemoglobins. Glycated hemoglobin measurements were compared in patients with low, moderate, or high hemoglobin glycation index (HGI), a measure of glycated hemoglobin controlled for blood glucose variation. MBG was not significantly different between HGI groups. Glycated hemoglobin levels measured by all three primary assays and in all four glycated 2D subfractions were significantly different between HGI groups and highest in high HGI patients. These results show that interindividual variation in glycated hemoglobin levels was evident in diabetes patients with similar blood glucose levels regardless of which glycated hemoglobins were measured.

  12. 21 CFR 864.8165 - Calibrator for hemoglobin or hematocrit measurement. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Calibrator for hemoglobin or hematocrit....8165 Calibrator for hemoglobin or hematocrit measurement. (a) Identification. A calibrator for hemoglobin or hematocrit measurement is a device that approximates whole blood, red blood cells, or...

  13. Comparable application of the OCT and Abbe refractometers for measurements of glycated hemoglobin portion in blood (United States)

    Zhernovaya, Olga S.; Tuchin, Valery V.; Wang, Ruikang K.


    It is known that glucose interacts with plasma proteins and hemoglobin in erythrocytes. Glycated (glycosylated) hemoglobin is the result of an irreversible non-enzymatic fixation of glucose on the beta chain of hemoglobin A. The amount of glycated hemoglobin depends on blood glucose concentration and reflects the mean glycemia of about the previous 2-3 months. Glycated hemoglobin is a useful marker for long-term glucose control in diabetic patients. Therefore, the search of quick and high sensitive methods for measurement of glycated hemoglobin portion in blood is important. This study is focused on the determination of refractive index of hemoglobin solution at different glucose concentrations. Measurements were performed using Abbe refractometer at 589 nm and optical coherence tomography (OCT) at 820 nm. The different amount of glucose (from 0 to 1000 mg/dl with a step 100 mg/dl) was added to hemoglobin solution. Theoretical values of refractive index of hemoglobin solutions with glucose were calculated supposing non-interacting hemoglobin and glucose molecules. There is a difference between measured and calculated values of refractive index. This difference is due to glucose binding to hemoglobin. It is shown that the refractive index measurements can be applied for the evaluation of glycated hemoglobin amount.

  14. A single hemoglobin gene in Myrica gale retains both symbiotic and non-symbiotic specificity

    DEFF Research Database (Denmark)

    Heckmann, Anne B.; Hebelstrup, Kim Henrik; Larsen, Knud


    Here, a hemoglobin gene from the nitrogen-fixing actinorhizal plant Myrica gale was isolated, cloned and sequenced. The gene (MgHb) was a class I hemoglobin with strong sequence homology to non-symbiotic hemoglobin genes. MgHb is highly expressed in symbiotic root nodules, but transcripts...

  15. Hemoglobin levels in persons with depressive and/or anxiety disorders

    NARCIS (Netherlands)

    Lever-van Milligen, Bianca A.; Vogelzangs, Nicole; Smit, Johannes H.; Penninx, Brenda W. J. H.


    Objective: Both low and high hemoglobin levels lead to more physical diseases, and both are linked to mortality. Low hemoglobin, often classified as anemia, has also been linked to more depressive symptoms, but whether both hemoglobin extremes are associated with depressive disorder and potentially

  16. Cyclic tetramers of a five-membered palladacycle based on a head-to-tail-linked isocyanate dimer and their reactivity in cyclotrimerization of isocyanates. (United States)

    Lee, Seon Gye; Choi, Keun-Young; Kim, Yong-Joo; Park, SuJin; Lee, Soon W


    Reactions of [Pd(styrene)(PR3)2], generated from trans-[PdEt2(PR3)2] and styrene, with 2 equiv. of benzyl isocyanate in THF at room-temperature afforded unusual cyclic Pd-tetramers of five-membered rings consisting of organic isocyanate dimers and palladium, [Pd(PR3){-C(O)N(R)C(O)N(R)-}]4 (PR3 = PMe3, ; PR3 = PMe2Ph, ). Additionally, a cyclic trimer, (RNCO)3, (R = benzyl) was produced as a catalytic product. Treatment of the cyclic tetramer () with 4 equiv. of chelated phosphine, such as (1,2-bis(diethylphosphino)ethane) (DEPE) or (1,2-bis(dimethylphosphino)ethane) (DMPE), readily caused conversion to a metallacyclic cis-form, [Pd{N(R)C(O)N(R)C(O)}(P ∼ P)] (P ∼ P = DEPE, ; P ∼ P = DMPE, ) in quantitative yields. In contrast, reactions of Pd(0)-PR3 with 2 equiv. of Ar-NCO (Ar = Ph, p-tolyl, p-ClC6H4) afforded metallacyclic complexes having a dimeric isocyanato moiety, cis-[Pd{C(O)N(Ar)-C(O)N(Ar)}(PR3)2] (PR3 = PMe3 Ar = C6H5, ; p-MeC6H4, ; p-Cl-C6H4, ; PR3 = PMe2Ph, Ar = p-Cl-C6H4, ). Treatment of the palladacyclic complex () with an equimolar amount of chelated phosphine such as DEPE readily caused conversion to a palladacyclic cis-form, [Pd{N(Ar)C(O)N(Ar)C(O)}(DEPE)], in quantitative yield. The catalytic cyclotrimerization of benzyl isocyanate to [Pd(styrene)(PMe3)2] was achieved by varying the molar ratio of R-NCO (R = benzyl). In addition, catalytic cyclotrimerization was performed from the five-membered palladacyclic complexes or the Pd(0)-PR3 complex with excess Ar-NCO.

  17. Evaluation of non cyanide methods for hemoglobin estimation

    Directory of Open Access Journals (Sweden)

    Vinaya B Shah


    Full Text Available Background: The hemoglobincyanide method (HiCN method for measuring hemoglobin is used extensively worldwide; its advantages are the ready availability of a stable and internationally accepted reference standard calibrator. However, its use may create a problem, as the waste disposal of large volumes of reagent containing cyanide constitutes a potential toxic hazard. Aims and Objective: As an alternative to drabkin`s method of Hb estimation, we attempted to estimate hemoglobin by other non-cyanide methods: alkaline hematin detergent (AHD-575 using Triton X-100 as lyser and alkaline- borax method using quarternary ammonium detergents as lyser. Materials and Methods: The hemoglobin (Hb results on 200 samples of varying Hb concentrations obtained by these two cyanide free methods were compared with a cyanmethemoglobin method on a colorimeter which is light emitting diode (LED based. Hemoglobin was also estimated in one hundred blood donors and 25 blood samples of infants and compared by these methods. Statistical analysis used was Pearson`s correlation coefficient. Results: The response of the non cyanide method is linear for serially diluted blood samples over the Hb concentration range from 3gm/dl -20 gm/dl. The non cyanide methods has a precision of + 0.25g/dl (coefficient of variation= (2.34% and is suitable for use with fixed wavelength or with colorimeters at wavelength- 530 nm and 580 nm. Correlation of these two methods was excellent (r=0.98. The evaluation has shown it to be as reliable and reproducible as HiCN for measuring hemoglobin at all concentrations. The reagents used in non cyanide methods are non-biohazardous and did not affect the reliability of data determination and also the cost was less than HiCN method. Conclusions: Thus, non cyanide methods of Hb estimation offer possibility of safe and quality Hb estimation and should prove useful for routine laboratory use. Non cyanide methods is easily incorporated in hemobloginometers

  18. Patterns of glycemic control using glycosylated hemoglobin in diabetics

    Directory of Open Access Journals (Sweden)

    Arunpreet Singh Kahlon


    Full Text Available Aim : Till now estimation of blood glucose is the highly effective method for diagnosing diabetes mellitus but it provides a short-term picture of control. More evidence is required to prove that plasma glucose and glycosylated hemoglobin levels together gives a better estimate of glycemic control and compliance with treatment. Indian diabetes risk score (IDRS is a simplified screening tool for identifying undiagnosed diabetic subjects, requires minimum time, and effort and can help to considerably reduce the costs of screening. Objective : To study patterns of glycemic control using glycosylated hemoglobin in diabetic patients. To find out correlation between levels of plasma glucose and glycosylated hemoglobin in diabetics and to calculate IDRS of the study population. Materials and Methods : A cross sectional study was conducted among 300 known diabetic patients attending outpatient department of a rural medical college in Haryana, India. Following standard procedures and protocols FPG and glycosylated hemoglobin were measured to find out a pattern of glycemic control in them after taking their written and informed consent. A correlation between the levels of glycosylated hemoglobin and fasting blood glucose was also calculated. These patients were made to fill a performa and their demographic and clinical risk factors were noted and based on this, their IDRS was calculated. This was done to validate the IDRS in Indian rural population. Results : Fifty-two percent of the population had fasting plasma glucose level between 125-150 mg/dl, 21% had this level between 151-175 mg/dl. Thirteen percent of the study subjects had HbA1C between 6.5-7.5, more than half (57.3% had this value between 7.5-8.5, 12% and 18% had values between 8.5-9.5 and 9.5-10.5, respectively. Twelve percent of the participants had HbA1C level higher than 10.5. Correlation of fasting plasma glucose level and HbA1C was also studied and found that correlation coefficient came

  19. High Level Expression of HLA-A*0203-BSP Fusion Protein in Escherichia coli and Construction of Soluble HLA-A*0203 Monomer and Tetramer Loaded with Epstein-Barr Virus Peptide

    Institute of Scientific and Technical Information of China (English)

    Qiantao Jia; Lihui Xu; Qingbing Zha; Xiaoyun Chi; Fengyao Li; Xianhui He


    Major histocompatibility complex (MHC) tetramer technology is critical for characterization of antigen-specific T cells. In the present study we reported the successful generation of HLA-A*0203 tetramer loaded with EpsteinBarr virus EBNA3596-604 peptide (SVRDRLARL, SVR). Prokaryotic expression vector for the ectodomain of the heavy chain of HLA-A*0203 fused with a BirA substrate peptide (HLA-A*0203-BSP) was constructed and the expression conditions of the fusion protein in Escherichia coli (E. Coli) were optimized. The fusion protein was highly expressed in inclusion bodies within E. Coli. It was then refolded in the presence of β2-microglobulin and SVR peptide to form a soluble HLA-A*0203-SVR monomer. After biotinylation with BirA, the monomer was purified by anion-exchange chromatography and its purity was up to 95%. The tetramer was then formulated by mixing the biotinylated monomer with streptavidin-PE at a ratio of 4:1. Flow cytometry showed that this tetramer could specifically react with antigen-specific CD8+ T cells, indicating that it was biologically functional. These results provide a foundation for further characterization of antigen-specific CD8+ T cells from HLA-A*0203 subjects.

  20. Selective formation of the [PhP(H)-PPh]- anion in the reaction of PhPHLi with MeAlCl(2); synthesis and structure of the unusual tetramer [(PhP(H)-PPh)Li.thf]4. (United States)

    Garcia, Felipe; Humphrey, Simon M; Kowenicki, Richard A; McPartlin, Mary; Wright, Dominic S


    The reaction of PhPHLi with MeAlCl(2)(3:1 equivalents) gives the tetramer [(PhP(H)-PPh)Li.thf]4, and provides the first direct evidence of a link between the reactivity patterns observed for Group 14 and 15 phosphanenides and those of Group 13.

  1. Effect of repeated benzene inhalation exposures on benzene metabolism, binding to hemoglobin, and induction of micronuclei. (United States)

    Sabourin, P J; Sun, J D; MacGregor, J T; Wehr, C M; Birnbaum, L S; Lucier, G; Henderson, R F


    Metabolism of benzene is thought to be necessary to produce the toxic effects, including carcinogenicity, associated with benzene exposure. To extrapolate from the results of rodent studies to potential health risks in man, one must know how benzene metabolism is affected by species, dose, dose rate, and repeated versus single exposures. The purpose of our studies was to determine the effect of repeated inhalation exposures on the metabolism of [14C]benzene by rodents. Benzene metabolism was assessed by characterizing and quantitating urinary metabolites, and by quantitating 14C bound to hemoglobin and micronuclei induction. F344/N rats and B6C3F1 mice were exposed, nose-only, to 600 ppm benzene or to air (control) for 6 hr/day, 5 days/week for 3 weeks. On the last day, both benzene-pretreated and control animals were exposed to 600 ppm, 14C-labeled benzene for 6 hr. Individual benzene metabolites in urine collected for 24 hr after the exposure were analyzed. There was a significant decrease in the respiratory rate of mice (but not rats) pretreated with benzene which resulted in lower levels of urinary [14C]benzene metabolites. The analyses indicated that the only effects of benzene pretreatment on the metabolite profile in rat or mouse urine were a slight shift from glucuronidation to sulfation in mice and a shift from sulfation to glucuronidation in rats. Benzene pretreatment also had no effect, in either species, on formation of [14C]benzene-derived hemoglobin adducts. Mice and rats had similar levels of hemoglobin adduct binding, despite the higher metabolism of benzene by mice. This indicates that hemoglobin adduct formation occurs with higher efficiency in rats. After 1 week of exposure to 600 ppm benzene, the frequency of micronucleated, polychromatic erythrocytes (PCEs) in mice was significantly increased. Exposure to the same level of benzene for an additional 2 weeks did not further increase the frequency of micronuclei in PCEs. These results indicate

  2. Hemoglobin concentrations and associated factors in adolescentes from Recife, Brazil

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    Elisângela Barros Soares Mendonça


    Full Text Available OBJECTIVE: To estimate the prevalence of anemia and associated factors in adolescents from the city of Recife in Pernambuco state. METHODS: This is a cross-sectional study, involving a random sample of 256 adolescents of both genders, aged 13 to 18, whose hemoglobin concentrations were evaluated, along with their nutritional status and socioeconomic and demographic characteristics. RESULTS: The prevalence of inadequate hemoglobin concentrations was 10.2% [CI95%=6.7-14.5], reaching levels considered as mild anemia (9 g/dL 0.05, nor with socioeconomic or demographic characteristics (p>0.05. CONCLUSION: Although the prevalence of anemia was low and classified as a mild health problem, preventive nutrition education involving the dissemination of healthy eating habits in schools and encouraging the consumption of iron-rich foods are strongly recommended.

  3. First Reported Case of Proliferative Retinopathy in Hemoglobin SE Disease

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    Paul Baciu


    Full Text Available We report the first case of proliferative sickle cell retinopathy in a patient with hemoglobin SE (Hb SE disease. Only a few dozen cases of Hb SE disease have been reported previously, and none had evidence of proliferative retinopathy. A 56-year-old African American man presented to our clinic for routine examination and was found to have sea-fan peripheral neovascularization bilaterally without maculopathy. Hemoglobin analysis revealed Hb SE heterozygosity. Sector laser photocoagulation to areas of nonperfusion in both eyes resulted in regression of the peripheral neovascularization over a period of 6 months. Although Hb SE disease is rare, the incidence of Hb SE disease is postulated to rise in the future. Awareness of its potential ocular complications is needed to appropriately refer these patients for screening.

  4. Induction of Fetal Hemoglobin In Vivo Mediated by a Synthetic γ-Globin Zinc Finger Activator

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    Flávia C. Costa


    Full Text Available Sickle cell disease (SCD and β-thalassemia patients are phenotypically normal if they carry compensatory hereditary persistence of fetal hemoglobin (HPFH mutations that result in increased levels of fetal hemoglobin (HbF, γ-globin chains in adulthood. Thus, research has focused on manipulating the reactivation of γ-globin gene expression during adult definitive erythropoiesis as the most promising therapy to treat these hemoglobinopathies. Artificial transcription factors (ATFs are synthetic proteins designed to bind at a specific DNA sequence and modulate gene expression. The artificial zinc finger gg1-VP64 was designed to target the −117 region of the Aγ-globin gene proximal promoter and activate expression of this gene. Previous studies demonstrated that HbF levels were increased in murine chemical inducer of dimerization (CID-dependent bone marrow cells carrying a human β-globin locus yeast artificial chromosome (β-YAC transgene and in CD34+ erythroid progenitor cells from normal donors and β-thalassemia patients. Herein, we report that gg1-VP64 increased γ-globin gene expression in vivo, in peripheral blood samples from gg1-VP64 β-YAC double-transgenic (bigenic mice. Our results demonstrate that ATFs function in an animal model to increase gene expression. Thus, this class of reagent may be an effective gene therapy for treatment of some inherited diseases.

  5. Structural determinants of ligand migration in Mycobacterium tuberculosis truncated hemoglobin O. (United States)

    Boechi, Leonardo; Martí, Marcelo A; Milani, Mario; Bolognesi, Martino; Luque, F Javier; Estrin, Darío A


    Mycobacterium tuberculosis is the causative agent of human tuberculosis, one of the most prevalent infectious diseases in the world. Its genome hosts the glbN and glbO genes coding for two proteins, truncated hemoglobin N (trHbN) and truncated hemoglobin O (trHbO), that belong to different groups (I and II, respectively) of the recently discovered trHb family of hemeproteins. The different expression pattern and kinetics rates constants for ligand association and NO oxidation rate suggest different functions for these proteins. Previous experimental and theoretical studies showed that, in trHbs, ligand migration along the internal tunnel cavity system is a key issue in determining the ligand-binding characteristics. The X-ray structure of trHbO has been solved and shows several internal cavities and secondary-docking sites. In this work, we present an extensive investigation of the tunnel/cavity system ofM. tuberculosis trHbO by means of computer-simulation techniques. We have computed the free-energy profiles for ligand migration along three found tunnels in the oxy and deoxy w.t. and mutant trHbO proteins. Our results show that multiple-ligand migration paths are possible and that several conserved residues such as TrpG8 play a key role in the ligand-migration regulation.

  6. The impact of H63D HFE gene carriage on hemoglobin and iron status in children. (United States)

    Barbara, Kaczorowska-Hac; Marcin, Luszczyk; Jedrzej, Antosiewicz; Wieslaw, Ziolkowski; Elzbieta, Adamkiewicz-Drozynska; Malgorzata, Mysliwiec; Ewa, Milosz; Jacek, Kaczor Jan


    The molecular mechanism that regulates iron homeostasis is based on a network of signals, which reflect on the iron requirements of the body. Hereditary hemochromatosis is a heterogenic metabolic syndrome which is due to unchecked transfer of iron into the bloodstream and its toxic effects on parenchymatous organs. It is caused by the mutation of genes that encode proteins that help hepcidin to monitor serum iron. These proteins include the human hemochromatosis protein -HFE, transferrin-receptor 2, hemojuvelin in rare instances, and ferroportin. HFE-related hemochromatosis is the most frequent form of the disease. Interestingly, the low penetrance of polymorphic HFE genes results in rare clinical presentation of the disease, predominantly in middle-aged males. Taking into account the wide dispersion of HFE mutation in our population and also its unknown role in heterozygotes, we analyzed the impact of H63D HFE carriage in the developmental age, with respect to gender, on the iron status and hemoglobin concentration of carriers in comparison to those of wild-type HFE gene (12.7 ± 3.07 years, 42 boys and 41 girls). H63D carriers presented higher blood iron, transferrin saturation, and ferritin concentration than wild-type probands (p iron and hemoglobin was noted. In conclusion, this study demonstrates that changes in iron metabolism occur at a young age in HFE heterozygotes.

  7. Forced chromatin looping raises fetal hemoglobin in adult sickle cells to higher levels than pharmacologic inducers. (United States)

    Breda, Laura; Motta, Irene; Lourenco, Silvia; Gemmo, Chiara; Deng, Wulan; Rupon, Jeremy W; Abdulmalik, Osheiza Y; Manwani, Deepa; Blobel, Gerd A; Rivella, Stefano


    Overcoming the silencing of the fetal γ-globin gene has been a long-standing goal in the treatment of sickle cell disease (SCD). The major transcriptional enhancer of the β-globin locus, called the locus control region (LCR), dynamically interacts with the developmental stage-appropriate β-type globin genes via chromatin looping, a process requiring the protein Ldb1. In adult erythroid cells, the LCR can be redirected from the adult β- to the fetal γ-globin promoter by tethering Ldb1 to the human γ-globin promoter with custom-designed zinc finger (ZF) proteins (ZF-Ldb1), leading to reactivation of γ-globin gene expression. To compare this approach to pharmacologic reactivation of fetal hemoglobin (HbF), hematopoietic cells from patients with SCD were treated with a lentivirus expressing the ZF-Ldb1 or with chemical HbF inducers. The HbF increase in cells treated with ZF-Ldb1 was more than double that observed with decitabine and pomalidomide; butyrate had an intermediate effect whereas tranylcypromine and hydroxyurea showed relatively low HbF reactivation. ZF-Ldb1 showed comparatively little toxicity, and reduced sickle hemoglobin (HbS) synthesis as well as sickling of SCD erythroid cells under hypoxic conditions. The efficacy and low cytotoxicity of lentiviral-mediated ZF-Ldb1 gene transfer compared with the drug regimens support its therapeutic potential for the treatment of SCD.

  8. Atherogenesis May Involve the Prooxidant and Proinflammatory Effects of Ferryl Hemoglobin

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    László Potor


    Full Text Available Oxidized cell-free hemoglobin (Hb, including covalently cross-linked Hb multimers, is present in advanced atherosclerotic lesions. Oxidation of Hb produces methemoglobin (Fe3+ and ferryl hemoglobin (Fe4+=O2−. Ferryl iron is unstable and can return to the Fe3+ state by reacting with specific amino acids of the globin chains. In these reactions globin radicals are produced followed by termination reactions yielding covalently cross-linked Hb multimers. Despite the evanescent nature of the ferryl state, herein we refer to this oxidized Hb as “ferryl Hb.” Our aim in this work was to study formation and biological effects of ferrylHb. We demonstrate that ferrylHb, like metHb, can release its heme group, leading to sensitization of endothelial cells (ECs to oxidant-mediated killing and to oxidation of low-density lipoprotein (LDL. Furthermore, we observed that both oxidized LDL and lipids derived from human atherosclerotic lesions trigger Hb oxidation and subsequent production of covalently cross-linked ferrylHb multimers. Previously we showed that ferrylHb disrupts EC monolayer integrity and induces expression of inflammatory cell adhesion molecules. Here we show that when exposed to ferrylHb, EC monolayers exhibit increased permeability and enhanced monocyte adhesion. Taken together, interactions between cell-free Hb and atheroma lipids engage in a vicious cycle, amplifying oxidation of plaque lipids and Hb. These processes trigger EC activation and cytotoxicity.

  9. Effect of some high consumption spices on hemoglobin glycation


    Naderi, G. H.; Narges J Dinani; S Asgary; M Taher; Nikkhoo, N.; Boshtam, M.


    Formation of glycation products is major factor responsible in complications of diabetes. Worldwide trend is toward the use of natural additives in reducing the complications of diseases. Therefore, there is a growing interest in natural antiglycation found in plants. Herbs and spices are one of the most important targets to search for natural antiglycation from the point of view of safety. This study investigated the ability of some of the spices to inhibit glycation process in a hemoglobin/...

  10. Temperature-dependent enthalpy of oxygenation in Antarctic fish hemoglobins

    DEFF Research Database (Denmark)

    Fago, A.; Wells, R.M.G.; Weber, Roy E.


    The effect of temperature on the oxygen-binding properties of the hemoglobins of three cold-adapted Antarctic fish species, Dissostichus mawsoni, Pagothenia borchgrevinki and Trematomus, sp., has been investigated under different pH values and buffer conditions. A clear non linear van't Hoff plot...... an adaptation to the low-temperature habitat needs to be revised. (C) 1997 Elsevier Science Inc Udgivelsesdato: 1997/10...

  11. The T-to-R transformation in hemoglobin: a reevaluation.


    Srinivasan, R.; Rose, G.D.


    The relationship between the T, R, and R2 quaternary forms of hemoglobin is examined by computational experiments. Contrary to previous suggestions, we propose that the R quaternary form may lie on the pathway from T to R2. This proposal is consistent with four independent observations. (i) Difference distance maps are used to identify those parts of the molecule that undergo conformational change upon oxygenation. The simplest interpretation of these maps brackets R between T and R2. (ii) Li...

  12. Fluorescence and reflectance properties of hemoglobin-pigmented skin disorders (United States)

    Troyanova, P.; Borisova, E.; Avramov, L.


    There has been growing interest in clinical application of laser-induced autofluorescence (LIAF) and reflectance spectroscopy (RS) to differentiate disease from normal surrounding tissue, including skin pathologies. Pigmented cutaneous lesions diagnosis plays important role in clinical practice, as malignant melanoma, which is characterized with greatest mortality from all skin cancer types, must be carefully discriminated form other colorized pathologies. The goals of this work were investigation of cutaneous hemoglobin-pigmented lesions (heamangioma, angiokeratoma, and fibroma) by the methods of LIAFS and RS. Spectra from healthy skin areas near to the lesion were detected to be used posteriori in analysis. Fluorescence and reflectance of cutaneous hemoglobin-pigmented lesions are used to develop criterion for differentiation from other pigmented pathologies. Origins of the spectral features obtained are discussed and determination of lesion types is achieved using selected spectral features. The spectral results, obtained were used to develop multispectral diagnostic algorithms based on the most prominent spectral features from the fluorescence and reflectance spectra of the lesions investigated. In comparison between normal skin and different cutaneous lesion types and between lesion types themselves sensitivities and specificities higher than 90 % were achieved. These results show a perspective possibility to differentiate hemoglobin-pigmented lesions from other pigmented pathologies using non-invasive and real time discrimination procedure.

  13. Reticulocyte hemoglobin content as a predictor of iron deficiency anemia

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    Ni Made Rini Suari


    Full Text Available Background Iron deficiency anemia (IDA is the most common form of anemia in developing countries, such as Indonesia. Iron deficiency anemia in children is a serious problem because it affects their growth and development. Early detection of IDA and subsequent treatment in childhood may prevent future health problems.Objective To assess the use of reticulocyte hemoglobin content (CHr to detect IDA in children aged 6-60 months.Methods We performed a cross-sectional study to measure the sensitivity and specificity of CHr compared to serum ferritin which is considered to be the gold standard for IDA diagnosis. The study was conducted from September 2011 to March 2013 in children aged 6-60 months who visited the Pediatric Outpatient Clinic, Sanglah Hospital, and Puskesmas II in West Denpasar. Data analysis was performed by 2x2 table. The results were assessed by area under the curve (AUC and receiver operating characteristic (ROC.Results Of 121 children underwent blood testing during the study period, 69 children were excluded because they did not have hypochromic microcytic anemia, leaving 52 subjects eligible for the study. The prevalence of IDA in this study was 31%. Reticulocyte hemoglobin content (CHr ≤ 23.1 pg had 88% (95%CI 71 to 100% sensitivity and 25% (95%CI 11 to 39% specificity.Conclusion Reticulocyte hemoglobin content < 23.1 pg may be a good predictor of IDA.

  14. Reference intervals for acetylated fetal hemoglobin in healthy newborns

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    Renata Paleari


    Full Text Available The acetylated fetal hemoglobin (AcHbF derives from an enzyme-mediated post-translational modification occurring on the N-terminal glycine residues of γ-chains. At present, no established data are available on reference intervals for AcHbF in newborns. A total of 92 healthy infants, with gestational age between 37 and 41 weeks were selected for the establishment of AcHbF reference intervals. Blood samples were collected by heel pricking, when collecting routine neonatal screening, and the hemoglobin pattern was analyzed by high-performance liquid chromatography. AcHbF results were then normalized for HbF content in order to account for differences in hemoglobin switch. No difference was found in AcHbF values between genders (P=0.858. AcHbF results were as follow: 12.8±0.8% (mean±standard deviation, reference interval: 11.3-14.3%. This finding could facilitate further studies aimed to assess the possible use of AcHbF, for instance as a possible fetal metabolic biomarker during pregnancy.

  15. IsdB-dependent hemoglobin binding is required for acquisition of heme by Staphylococcus aureus. (United States)

    Pishchany, Gleb; Sheldon, Jessica R; Dickson, Claire F; Alam, Md Tauqeer; Read, Timothy D; Gell, David A; Heinrichs, David E; Skaar, Eric P


    Staphylococcus aureus is a Gram-positive pathogen responsible for tremendous morbidity and mortality. As with most bacteria, S. aureus requires iron to cause disease, and it can acquire iron from host hemoglobin. The current model for staphylococcal hemoglobin-iron acquisition proposes that S. aureus binds hemoglobin through the surface-exposed hemoglobin receptor IsdB. IsdB removes heme from bound hemoglobin and transfers this cofactor to other proteins of the Isd system, which import and degrade heme to release iron in the cytoplasm. Here we demonstrate that the individual components of the Isd system are required for growth on low nanomolar concentrations of hemoglobin as a sole source of iron. An in-depth study of hemoglobin binding by IsdB revealed key residues that are required for hemoglobin binding. Further, we show that these residues are necessary for heme extraction from hemoglobin and growth on hemoglobin as a sole iron source. These processes are found to contribute to the pathogenicity of S. aureus in a murine model of infection. Together these results build on the model for Isd-mediated hemoglobin binding and heme-iron acquisition during the pathogenesis of S. aureus infection.

  16. Pancreatic ascites hemoglobin contributes to the systemic response in acute pancreatitis. (United States)

    Pérez, Salvador; Pereda, Javier; Sabater, Luis; Sastre, Juan


    Upon hemolysis extracellular hemoglobin causes oxidative stress and cytotoxicity due to its peroxidase activity. Extracellular hemoglobin may release free hemin, which increases vascular permeability, leukocyte recruitment, and adhesion molecule expression. Pancreatitis-associated ascitic fluid is reddish and may contain extracellular hemoglobin. Our aim has been to determine the role of extracellular hemoglobin in the local and systemic inflammatory response during severe acute pancreatitis in rats. To this end we studied taurocholate-induced necrotizing pancreatitis in rats. First, extracellular hemoglobin in ascites and plasma was quantified and the hemolytic action of ascitic fluid was tested. Second, we assessed whether peritoneal lavage prevented the increase in extracellular hemoglobin in plasma during pancreatitis. Third, hemoglobin was purified from rat erythrocytes and administered intraperitoneally to assess the local and systemic effects of ascitic-associated extracellular hemoglobin during acute pancreatitis. Extracellular hemoglobin and hemin levels markedly increased in ascitic fluid and plasma during necrotizing pancreatitis. Peroxidase activity was very high in ascites. The peritoneal lavage abrogated the increase in extracellular hemoglobin in plasma. The administration of extracellular hemoglobin enhanced ascites; dramatically increased abdominal fat necrosis; upregulated tumor necrosis factor-α, interleukin-1β, and interleukin-6 gene expression; and decreased expression of interleukin-10 in abdominal adipose tissue during pancreatitis. Extracellular hemoglobin enhanced the gene expression and protein levels of vascular endothelial growth factor (VEGF) and other hypoxia-inducible factor-related genes in the lung. Extracellular hemoglobin also increased myeloperoxidase activity in the lung. In conclusion, extracellular hemoglobin contributes to the inflammatory response in severe acute pancreatitis through abdominal fat necrosis and inflammation

  17. Erythropoietin, Iron Depletion and Relative Thrombocytosis: A Possible Explanation for Hemoglobin-Survival Paradox in Chronic Kidney Disease (United States)

    Streja, Elani; Kovesdy, Csaba P; Greenland, Sander; Kopple, Joel D.; McAllister, Charles J; Nissenson, Allen R; Kalantar-Zadeh, Kamyar


    Background High doses of human recombinant erythropoietin (rHuEPO) to achieve hemoglobin levels above 13 g/dL in chronic kidney disease appear associated with elevated mortality. Study Design We conducted logistic regression and survival analyses in a retrospective cohort of maintenance hemodialysis (MHD) patients to examine the hypothesis that the induced iron depletion with resultant relative thrombocytosis may be a possible contributor to the link between the high rHuEPO dose associated hemoglobin ≥13 g/dL and mortality. Setting & Participants The national database of a large dialysis organization (DaVita) with 40,787 MHD patients during July to December 2001 and their survival up to July 2004 were examined. Predictors Hemoglobin level, platelet count and administered rHuEPO dose during each calendar quarter. Outcomes & other Measurements Case-mix adjusted 3-year all-cause mortality; and measures of iron stores including serum ferritin and iron saturation ratio (ISAT). Results Higher platelet count was associated with lower iron stores and higher prescribed rHuEPO dose. Compared to hemoglobin of 12-13 g/dL, hemoglobin ≥13 g/dL was associated with increased mortality in the presence of relative thrombocytosis, i.e., platelet count ≥300,000/μl, (case-mix adjusted death-rate ratio [RR]: 1.21, 95% confidence limits [CL]: 1.02–1.44, P=0.03) as opposed to the absence of relative thrombocytosis (RR: 1.04, 95% CL: 0.98–1.08, P=0.13). Prescribed rHuEPO dose >20,000 units/week was associated with higher likelihood of iron depletion (ISATthrombocytosis (case-mix adjusted odds ratio: 2.53 [CL: 2.37–2.69] and 1.36 [CL: 1.30–1.42], respectively, pthrombocytosis might contribute to increased mortality when administering high rHuEPO doses to achieve hemoglobin ≥13 g/dL in MHD patients. Randomized trials are needed to test these observational associations. PMID:18760517

  18. Current hemoglobin levels are more predictive of disease progression than hemoglobin measured at baseline in patients receiving antiretroviral treatment for HIV type 1 infection

    DEFF Research Database (Denmark)

    Kowalska, Justyna D; Mocroft, Amanda; Blaxhult, Anders;


    The role of hemoglobin levels as an independent prognostic marker of progression to AIDS and/or death in HIV-infected patients starting combination antiretroviral therapy (cART) was investigated. A total of 2,579 patients from the EuroSIDA cohort with hemoglobin, CD4 cell count, and HIV RNA viral...

  19. Facile synthesis of copper(II)-decorated magnetic particles for selective removal of hemoglobin from blood samples. (United States)

    Ding, Chun; Ma, Xiangdong; Yao, Xin; Jia, Li


    In this report, the Cu(2+)-immobilized magnetic particles were prepared by a facile route and they were used as adsorbents for removal of high abundance of hemoglobin in blood based on immobilized metal affinity chromatography. Ethylenediaminetetraacetic acid modified magnetic particles (EDTA-Fe3O4) were first synthesized through a one-pot solvothermal method and then charged with copper ions. The as-prepared Cu(2+)-EDTA-Fe3O4 particles were characterized by Fourier transform infrared spectrometry, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, vibrating sample magnetometry and zeta potential. Factors affecting the adsorption of bovine hemoglobin on Cu(2+)-EDTA-Fe3O4 particles (including contact time, solution pH, ionic strength and initial concentration of protein) were investigated. The adsorption process followed a pseudo-second-order kinetic model and the adsorption equilibrium could be achieved in 60min. The adsorption isotherm data could be well described by a Langmuir model and the maximum adsorption capacity was 1250mgg(-1). The as-prepared particles showed high efficiency and excellent selectivity for removal of hemoglobin from bovine and human blood. The removal process integrated the selectivity of immobilized metal affinity chromatography and the convenience of magnetic separation. The results demonstrated that Cu(2+)-EDTA-Fe3O4 particles had potential application in removal of abundant histidine-rich proteins in biomedical diagnosis analysis.

  20. Resveratrol: Antioxidant activity and induction of fetal hemoglobin in erythroid cells from normal donors and β-thalassemia patients. (United States)

    Fibach, Eitan; Prus, Eugenia; Bianchi, Nicoletta; Zuccato, Cristina; Breveglieri, Giulia; Salvatori, Francesca; Finotti, Alessia; Lipucci di Paola, Michele; Brognara, Eleonora; Lampronti, Ilaria; Borgatti, Monica; Gambari, Roberto


    Thalassemia and sickle-cell anemia (SCA) present a major public health problem in countries where the number of carriers and affected individuals is high. As a result of the abnormalities in hemoglobin production, cells of thalassemia and SCA patients exhibit oxidative stress, which ultimately is responsible for the chronic anemia observed. Therefore, identification of compounds exhibiting both antioxidant and hemoglobin-inducing activities is highly needed. Our results demonstrate resveratrol to be such a compound. This was shown both in the human K562 cell line, as well as in erythroid precursors derived from normal donors and β-thalassemia patients. Resveratrol was shown to exhibit antioxidant activity and to stimulate the expression of the γ-globin genes and the accumulation of fetal hemoglobin (HbF). To the best of our knowledge, this is the first report pointing to such a double effect of resveratrol. Since this natural product is already marketed as an antioxidant, future investigations should concentrate on demonstrating its potential to augment HbF production in experimental animal models (e.g., thalassemia and SCA mice) as well as in patients. We believe that the potential of clinical use of resveratrol as an antioxidant and HbF stimulator may offer a simple and inexpensive treatment to patients.

  1. Clinical, hematological and genetic data of a cohort of children with hemoglobin SD

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    Paulo do Val Rezende

    Full Text Available ABSTRACT INTRODUCTION: The hemoglobin FSD is very uncommon in newborn screening programs for sickle cell disease. In the program of Minas Gerais, Brazil, the clinical course of children with hemoglobin SD was observed to be heterogeneous. The objective of this study was to estimate the incidence (1999-2012 and to describe the natural history of a cohort of newborns with hemoglobin SD. METHODS: Isoelectric focusing was the primary method used in newborn screening. Polymerase chain reaction-restriction fragment length polymorphism and gene sequencing were used to identify mutant alleles and for haplotyping. Gap-polymerase chain reaction was used to detect alpha-thalassemia. RESULTS: Eleven cases of hemoglobin S/D-Punjab and eight of Hb S-Korle Bu were detected. Other variants with hemoglobin D mobility were not identified. All hemoglobin D-Punjab and hemoglobin Korle Bu alleles were associated with haplotype I. Among the children with hemoglobin S/D-Punjab, there were four with the ßS CAR haplotype, six with the Benin haplotype, and one atypical. Results of laboratory tests for hemoglobin S/D-Punjab and hemoglobin S-Korle Bu were: hemoglobin 8.0 and 12.3 g/dL (p-value <0.001, leukocyte count 13.9 × 109/L and 10.5 × 109/L (p-value = 0.003, reticulocytes 7.5% and 1.0% (p-value <0.001, hemoglobin F concentration 16.1% and 6.9% (p-value = 0.001 and oxygen saturation 91.9% and 97% (p-value = 0.002, respectively. Only hemoglobin S/D-Punjab children had acute pain crises and needed blood transfusions or hydroxyurea. Those with the Benin ßS haplotype had higher total hemoglobin and hemoglobin F concentrations compared to the CAR haplotype. Transcranial Doppler was normal in all children. CONCLUSION: The clinical course and blood cell counts of children with hemoglobin S/D-Punjab were very similar to those of hemoglobin SS children. In contrast, children with hemoglobin S-Korle Bu had clinical course and blood cell counts like children with the sickle

  2. A small-angle X-ray scattering study of alpha-synuclein from human red blood cells. (United States)

    Araki, Katsuya; Yagi, Naoto; Nakatani, Rie; Sekiguchi, Hiroshi; So, Masatomo; Yagi, Hisashi; Ohta, Noboru; Nagai, Yoshitaka; Goto, Yuji; Mochizuki, Hideki


    α-synuclein (α-syn) is the main component of Lewy bodies, which are neuropathological hallmarks of patients with Parkinson's disease. As it has been controversial whether human α-syn from erythrocytes exists as a tetramer under physiological conditions, we tried solving this issue by the small-angle X-ray solution scattering method. Under two different conditions (high ionic strength with a Tris buffer and low ionic strength with an ammonium acetate buffer), no evidence was found for the presence of tetramer. When comparing erythrocyte and recombinant α-syn molecules, we found no significant difference of the molecular weight and the secondary structure although the buffer conditions strongly affect the radius of gyration of the protein. The results indicate that, even though a stable tetramer may not be formed, conformation of α-syn depends much on its environment, which may be the reason for its tendency to aggregate in cells.

  3. Confirmation of Structural Variants of Hemoglobin Using Acid Gel in Hydrasis Technology

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    Jacqueline Pérez Rodríguez


    Full Text Available Background: The National Medical Genetics Center has conducted a research on the major hemoglobin abnormalities of clinical interest (HbS, HbC present in pregnant women in the province of Artemisa, using Hydrasis technology with alkaline agarose gels. The use of these gels does not allow distinguishing hemoglobin S from hemoglobin D or hemoglobin C from hemoglobin E, as these hemoglobins migrate in the same position. Objective: to assess the use of acid gel to differentiate haemoglobin D from haemoglobin E by their mobility in hemoglobin electrophoresis. Methods: a descriptive study was conducted using hemoglobin electrophoresis with Hydrasis technology to analyze 200 biological samples of whole blood from pregnant women and individuals with sicklemia or carrying the disease. The acceptance limits included a correlation of electrophoresis run in acid gel in relation to alkaline gel, b correct migration of the hemoglobin bands and c good interpretation of the results. Results: 98 % of the samples analyzed with acid gel showed correspondence with those obtained with alkaline gel. It was not possible to determine and confirm the hemoglobin variant in three samples. Conclusions: the use of acid gels in electrophoresis run with the Hydrasis technology provided results which confirm the diagnosis of hemoglobinopathies.

  4. Structural basis for hemoglobin capture by Staphylococcus aureus cell-surface protein, IsdH. (United States)

    Krishna Kumar, Kaavya; Jacques, David A; Pishchany, Gleb; Caradoc-Davies, Tom; Spirig, Thomas; Malmirchegini, G Reza; Langley, David B; Dickson, Claire F; Mackay, Joel P; Clubb, Robert T; Skaar, Eric P; Guss, J Mitchell; Gell, David A


    Pathogens must steal iron from their hosts to establish infection. In mammals, hemoglobin (Hb) represents the largest reservoir of iron, and pathogens express Hb-binding proteins to access this source. Here, we show how one of the commonest and most significant human pathogens, Staphylococcus aureus, captures Hb as the first step of an iron-scavenging pathway. The x-ray crystal structure of Hb bound to a domain from the Isd (iron-regulated surface determinant) protein, IsdH, is the first structure of a Hb capture complex to be determined. Surface mutations in Hb that reduce binding to the Hb-receptor limit the capacity of S. aureus to utilize Hb as an iron source, suggesting that Hb sequence is a factor in host susceptibility to infection. The demonstration that pathogens make highly specific recognition complexes with Hb raises the possibility of developing inhibitors of Hb binding as antibacterial agents.

  5. Importance of Many-Body Effects in the Kernel of Hemoglobin for Ligand Binding (United States)

    Weber, Cédric; O'Regan, David D.; Hine, Nicholas D. M.; Littlewood, Peter B.; Kotliar, Gabriel; Payne, Mike C.


    We propose a mechanism for binding of diatomic ligands to heme based on a dynamical orbital selection process. This scenario may be described as bonding determined by local valence fluctuations. We support this model using linear-scaling first-principles calculations, in combination with dynamical mean-field theory, applied to heme, the kernel of the hemoglobin metalloprotein central to human respiration. We find that variations in Hund’s exchange coupling induce a reduction of the iron 3d density, with a concomitant increase of valence fluctuations. We discuss the comparison between our computed optical absorption spectra and experimental data, our picture accounting for the observation of optical transitions in the infrared regime, and how the Hund’s coupling reduces, by a factor of 5, the strong imbalance in the binding energies of heme with CO and O2 ligands.

  6. I-Ag7和I-Ad四聚体的交叉反应性%The cross-reactivity of I-Ag7 and I-Ad tetramers

    Institute of Scientific and Technical Information of China (English)


    目的研究糖尿病易感性NOD小鼠(I-Ag7)和非糖尿病性Balb/c(I-Ad)中谷氨酸去羰基酶 (GAD)-I-Ag7 and I-Ad 四聚体的交叉反应性.方法合成两种GAD多肽-I-Ag7 and I-Ad 四聚体,并比较这两种四聚体阳性细胞(tet +)的表现型及功能.结果交叉反应性不仅表现在四聚体阳性细胞率上,而且在四聚体染色强度上.NOD 和 Balb/c来源的tet+ T细胞均能被 GAD抗原肽-I-Ag7 和I-Ad 四聚体交叉染色,并在合成的和重组的GAD抗原肽刺激下均对辐射后的NOD和Balb/c脾细胞有交叉反应. 讨论虽然I-Ag7 and I-Ad 在生物化学和生物学特性上近似,关键的区别在于β57上的氨基酸种类,这与I型糖尿病的发病密切相关.%Objective To investigate the cross-reactivity between glutamic acid decarboxylase (GAD)- I-Ag7 and I-Ad tetramer in diabetes-prone non-obese diabetic (NOD) mice (I-Ag7) and diabetes-free Balb/c mice (I-Ad). Methods Two GAD peptide I-Ag7 and I-Ad tetramers were generated and compared for phenotype and function of sorted GAD peptide I-Ag7 and I-Ad tetrame r-positive (tet+) T cells.Results The cross-reactivity is shown in either tetramer positive percentage or tetramer staining intensity. The NOD and Balb/c derived-tet+ T cells were able to be cross-stained by GAD peptide I-Ag7 and I-Ad tetramers, and responded to both irradiated NOD and Balb/c splenotyes under stimulation by synthetic an drecombinant GAD peptides. Conclusion Although I-Ag7 and I-Ad are closely related in biochemical and biological aspects, their most notable difference is the presence or absence of a negat ively charged residue at position β57 that links to insulin-dependent diabetes mellitus.

  7. Use of “one-pot, mix-and-read” peptide-MHC class I tetramers and predictive algorithms to improve detection of cytotoxic T lymphocyte responses in cattle (United States)


    Peptide-major histocompatibility complex (p-MHC) class I tetramer complexes have facilitated the early detection and functional characterisation of epitope specific CD8+ cytotoxic T lymphocytes (CTL). Here, we report on the generation of seven recombinant bovine leukocyte antigens (BoLA) and recombinant bovine β2-microglobulin from which p-MHC class I tetramers can be derived in ~48 h. We validated a set of p-MHC class I tetramers against a panel of CTL lines specific to seven epitopes on five different antigens of Theileria parva, a protozoan pathogen causing the lethal bovine disease East Coast fever. One of the p-MHC class I tetramers was tested in ex vivo assays and we detected T. parva specific CTL in peripheral blood of cattle at day 15-17 post-immunization with a live parasite vaccine. The algorithm NetMHCpan predicted alternative epitope sequences for some of the T. parva CTL epitopes. Using an ELISA assay to measure peptide-BoLA monomer formation and p-MHC class I tetramers of new specificity, we demonstrate that a predicted alternative epitope Tp229-37 rather than the previously reported Tp227-37 epitope is the correct Tp2 epitope presented by BoLA-6*04101. We also verified the prediction by NetMHCpan that the Tp587-95 epitope reported as BoLA-T5 restricted can also be presented by BoLA-1*02301, a molecule similar in sequence to BoLA-T5. In addition, Tp587-95 specific bovine CTL were simultaneously stained by Tp5-BoLA-1*02301 and Tp5-BoLA-T5 tetramers suggesting that one T cell receptor can bind to two different BoLA MHC class I molecules presenting the Tp587-95 epitope and that these BoLA molecules fall into a single functional supertype. PMID:24775445

  8. RAP-011, an activin receptor ligand trap, increases hemoglobin concentration in hepcidin transgenic mice. (United States)

    Langdon, Jacqueline M; Barkataki, Sangjucta; Berger, Alan E; Cheadle, Chris; Xue, Qian-Li; Sung, Victoria; Roy, Cindy N


    Over expression of hepcidin antimicrobial peptide is a common feature of iron-restricted anemia in humans. We investigated the erythroid response to either erythropoietin or RAP-011, a "murinized" ortholog of sotatercept, in C57BL/6 mice and in hepcidin antimicrobial peptide 1 over expressing mice. Sotatercept, a soluble, activin receptor type IIA ligand trap, is currently being evaluated for the treatment of anemias associated with chronic renal disease, myelodysplastic syndrome, β-thalassemia, and Diamond Blackfan anemia and acts by inhibiting signaling downstream of activin and other Transforming Growth Factor-β superfamily members. We found that erythropoietin and RAP-011 increased hemoglobin concentration in C57BL/6 mice and in hepcidin antimicrobial peptide 1 over expressing mice. While erythropoietin treatment depleted splenic iron stores in C57BL/6 mice, RAP-011 treatment did not deplete splenic iron stores in mice of either genotype. Bone marrow erythroid progenitors from erythropoietin-treated mice exhibited iron-restricted erythropoiesis, as indicated by increased median fluorescence intensity of transferrin receptor immunostaining by flow cytometry. In contrast, RAP-011-treated mice did not exhibit the same degree of iron-restricted erythropoiesis. In conclusion, we have demonstrated that RAP-011 can improve hemoglobin concentration in hepcidin antimicrobial peptide 1 transgenic mice. Our data support the hypothesis that RAP-011 has unique biologic effects which prevent or circumvent depletion of mouse splenic iron stores. RAP-011 may, therefore, be an appropriate therapeutic for trials in human anemias characterized by increased expression of hepcidin antimicrobial peptide and iron-restricted erythropoiesis. © 2014 Wiley Periodicals, Inc.

  9. Low levels of serum ferritin and moderate transferrin saturation lead to adequate hemoglobin levels in hemodialysis patients, retrospective observational study. (United States)

    Ogawa, Chie; Tsuchiya, Ken; Tomosugi, Naohisa; Kanda, Fumiyoshi; Maeda, Kunimi; Maeda, Teiryo


    Optimal iron levels in patients on hemodialysis are currently unknown, and a higher level than that for the healthy population is usually set for such patients considering the use of erythropoiesis-stimulating agents or the occurrence of chronic inflammation. However, excessive iron causes oxidative stress and impairment of its utilization by cells. Therefore we investigated the relationship between hemoglobin (Hb) level and iron status in hemodialysis patients to identify the optimal iron levels for patients undergoing hemodialysis. A total of 208 outpatients on maintenance hemodialysis were followed up between July 2006 and June 2007. Men accounted for 64.9% cases [mean age, 59.3 ± 13.1 years and median dialysis history, 7.7 (3.6-13.2) years], and diabetic nephropathy accounted for 25.0% cases. Hemoglobin level was measured twice a month and serum ferritin, serum iron, and total iron-binding capacity were measured once a month. The doses of recombinant human erythropoietin and low-dose iron supplement were adjusted to maintain a hemoglobin level of 10-11 g/dL, according to the guidelines of the Japanese Society for Dialysis Therapy. Hepcidin was measured at baseline. Using the mean values for 1-year period, the relationships among hemoglobin, serum ferritin levels, and transferrin saturation levels were investigated based on a receiver operating characteristic curve and a logistic regression model. In addition, the correlations among serum ferritin, transferrin saturation, and hepcidin levels were analyzed by Pearson product-moment correlation coefficient and linear regression model. By receiver operating characteristic curve, the cutoff point of serum ferritin and transferrin saturation levels with a hemoglobin ≥10 g/dL showed serum ferritin ≥90 ng/mL and transferrin saturation serum ferritin serum ferritin [r = 0.78 (95% confidence interval: 0.72-0.83, p serum ferritin [β-coefficient of 0.30 (95% confidence interval: 0.27-0.34, p serum ferritin <90 ng

  10. Fetal hemoglobin accumulation in vitro. Effect of adherent mononuclear cells.


    Javid, J; Pettis, P K


    In clonal cultures of erythroid burst-forming units (BFU-E) obtained from blood, the accumulation of fetal and adult hemoglobins (Hb F and Hb A) was measured by radioligand immunoassay. Inclusion of adherent mononuclear cells in the culture promoted a striking increase in the relative amount of Hb F in each of 44 experiments with 14 donors. In two-thirds of the instances, this was accounted for by a selective increase in the absolute amount of Hb F. The differential effect on Hb F and Hb A ac...

  11. Deferiprone: structural and functional modulating agent of hemoglobin fructation. (United States)

    Sattarahmady, Naghmeh; Heli, Hossein; Moosavi-Movahedi, Ali A; Karimian, K


    Diabetic complication arises from the presence of advanced glycation end products in different sites of the body. Great attention should be paid to recognizing anti-glycation compounds. Here, deferiprone as an oral iron chelator drug administrated in treatment of β-thalassemic patients was selected to find its effect on the fructation of hemoglobin (Hb). Our results indicated that deferiprone could prevent the AGE and carbonyl formation via inhibition of structural changes in the structure of Hb during the fructation process. Moreover, deferiprone can preserve peroxidase and esterase activities of fructated Hb similar to native Hb. Therefore, deferiprone can be introduced as an anti-glycation drug to prevent the AGE formation.

  12. Hemoglobin A1c: Standardizacija “zlatnog standarda”



    Hemoglobin A1c (HbA1c) je u proteklih 30 godina primjene postao "zlatnim standardom" u kliničkom praćenju šećerne bolesti. Dobra kontrola glikemije, izražena kroz koncentraciju HbA1c ≤7%, danas je klinički normativ kroz koji se procjenjuje djelotvornost terapije i rizik pojave komplikacija šećerne bolesti i glavna tema komunikacije između dijabetologa i pacijenata. Raznovrsna i nestandardizirana metodologija, varijabilnost kemijskih entiteta nastalih glikacijom molekule hemoglobina i nepos...

  13. Interference of fetal hemoglobin with the spectrophotometric measurement of carboxyhemoglobin. (United States)

    Vreman, H J; Ronquillo, R B; Ariagno, R L; Schwartz, H C; Stevenson, D K


    We measured the concentration of carboxyhemoglobin (HbCO) in blood samples from 32 neonates by spectrophotometry (IL282 CO-Oximeter) and gas chromatography, finding a strong positive correlation (r = 0.89) between the concentration of fetal hemoglobin (Hb F) and HbCO as measured by spectrophotometry, but not by gas chromatography. Thus, Hb F interferes with the determination of HbCO by spectrophotometric techniques by falsely increasing apparent HbCO in direct proportion to Hb F. We conclude that, when Hb F is known or suspected to be present, blood HbCO cannot be reliably determined by methods based on spectrophotometry.

  14. Hemoglobinas AS/alfa talassemia: importância diagnóstica Hemoglobins AS/alpha thalassemia: diagnostic importance

    Directory of Open Access Journals (Sweden)

    Renata Tomé-Alves


    , the Sickle Cell beta Thalassemia syndromes, and Hemoglobinopathies in which hemoglobin S is in association with another abnormal hemoglobin, such as hemoglobin S/C. The Sickle Cell trait (hemoglobin AS associated with Alpha Thalassemia presents alterations in the red blood cells morphology, usually absent in the heterozygous for this hemoglobin variant. The interaction between hemoglobin S and alpha Thalassemia has been described as one of the factors responsible for the improvement in the clinical picture of homozygous of hemoglobin S (Sickle Cell Anemia, decreasing the number of episodes of pain. The genetic mechanisms of this influence are evaluated using molecular analyses of the human globin genes. With the objective of verifying the presence of alpha Thalassemia in heterozygous of hemoglobin S, with anemia, sent to the Laboratory of Hemoglobins, Department of Biology, UNESP, São José do Rio Preto, SP, we analyzed 1002 blood samples with Sickle Cell trait, in the period from 1990 to 1998. The samples were picked with EDTA 5% as anticoagulant, after previous authorization of the carriers. Appropriated counseling and management requires definitive diagnosis. For the laboratorial diagnosis the blood samples were submitted to electrophoretic procedures in alkaline and acid pH and cytological evaluation of hemoglobin H. The electrophoretic procedures confirmed the presence of hemoglobin AS. The cytological evaluation evidenced the presence of alpha Thalassemia. Of this total analyzed, 16(1,59% blood samples presented the association between hemoglobin AS and alpha Thalassemia and two individuals belonged of the same family. Our results addressed us to suggest to the routine laboratories, that is important to accomplish the research of alpha Thalassemia among the Sickle Cell trait, with anemia, to verify the interaction with alpha Thalassemia, supplying to the carriers a important information on its hematological profile, genetic pattern of hemoglobinopathies and the

  15. Unusual self-assembled 1D tape of tetramers and water-nitrate clusters trapped in a zinc(II) complex: Synthesis, characterization, luminescence and catalytic properties (United States)

    Ma, De-Yun; Guo, Hai-Fu; Dong, Ji; Xu, Jun


    Unusual tetramers and water-nitrate clusters have been observed in a mononuclear zinc(II) complex of [Zn(4-cpa)(phen)2(H2O)]·(H2O)·(NO3)] (1), (4-Hcpa = 4-chlorophenoxyacetic acid, phen = 1,10-phenanthroline), which was synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis (TGA), powder X-ray diffraction, UV-vis absorption spectra and single-crystal X-ray diffraction. The crystal structure analysis of 1, reveals that the nitrate anions, water molecules and carboxylate oxygen atoms (O3) pack to form a one-dimensional infinite tape parallel to the c-axis. The uncoordinated carboxylate oxygen atoms (O3) of 4-cpa ligands, water molecules and nitrate anions interact via hydrogen bonds and extend 1 into a water-anion-cation tape, which are finally connected into a 3D supramolecular structure via π⋯π stacking interactions. Excitation (λex = 310 nm) and luminescence data observed at room temperature show that 1 emits bright blue fluorescence. Moreover, 1 has a remarkable activity for degradation of methyl orange in a photo-assisted Fenton-like process.

  16. Tetramer spin singlet instability in the fluorine-substituted pyrochlore superconducting system Cd2Re2O7-x F x. (United States)

    Haraguchi, Yuya; Michioka, Chishiro; Ueda, Hiroaki; Yoshimura, Kazuyoshi


    We synthesized polycrystalline samples of the fluorine-substituted pyrochlore rhenates Cd2Re2O7-x F x , and investigated their magnetic, transport and structural properties. The transition temperature T s1, where each Re4 tetrahedron in the Re pyrochlore network alternately expands and contracts, decreases with increasing x from 200 K at x  =  0 to 100 K at x  =  0.5. The strong x dependence of the magnetic and transport properties at the low-temperature phase indicates that the driving force of structural phase transition is fluctuations of the tetramer spin singlet formation in order to release the spin frustration in the pyrochlore lattice. Furthermore, we found unconventional superconducting properties in Cd2Re2O7-x F x . It was found that the superconducting phase transition temperature T c markedly decreases with increasing x, suggesting that the addition of imperfection suppresses a condensation of Cooper-pair. In addition, the estimated upper critical field at zero temperature exceeds the Pauli paramagnetic limit and increases with increasing x in spite of the reduction of T c. Hence, Cd2Re2O7-x F x is suggested to be an exotic superconductor realized in the itinerant electron systems on a spin frustrated lattice.

  17. Tetramer spin singlet instability in the fluorine-substituted pyrochlore superconducting system Cd2Re2O7-x F x (United States)

    Haraguchi, Yuya; Michioka, Chishiro; Ueda, Hiroaki; Yoshimura, Kazuyoshi


    We synthesized polycrystalline samples of the fluorine-substituted pyrochlore rhenates Cd2Re2O7-x F x , and investigated their magnetic, transport and structural properties. The transition temperature T s1, where each Re4 tetrahedron in the Re pyrochlore network alternately expands and contracts, decreases with increasing x from 200 K at x  =  0 to 100 K at x  =  0.5. The strong x dependence of the magnetic and transport properties at the low-temperature phase indicates that the driving force of structural phase transition is fluctuations of the tetramer spin singlet formation in order to release the spin frustration in the pyrochlore lattice. Furthermore, we found unconventional superconducting properties in Cd2Re2O7-x F x . It was found that the superconducting phase transition temperature T c markedly decreases with increasing x, suggesting that the addition of imperfection suppresses a condensation of Cooper-pair. In addition, the estimated upper critical field at zero temperature exceeds the Pauli paramagnetic limit and increases with increasing x in spite of the reduction of T c. Hence, Cd2Re2O7-x F x is suggested to be an exotic superconductor realized in the itinerant electron systems on a spin frustrated lattice.

  18. Long-term variation in hemoglobin concentration in nestling great tits Parus major. (United States)

    Kaliński, Adam; Bańbura, Mirosława; Glądalski, Michał; Markowski, Marcin; Skwarska, Joanna; Wawrzyniak, Jarosław; Zieliński, Piotr; Cyżewska, Iwona; Bańbura, Jerzy


    Several studies have previously proposed that blood hemoglobin concentration in nestling passerines is a reliable index of individual condition and nutritional state. In this paper we present results concerning variation in hemoglobin concentration in the blood of ca. 14-day-old nestling great tits Parus major in central Poland in an 11-year-long period, 2003-2013, in two distinct habitat types: urban park and deciduous forest. The most important findings of the study were: (i) variation in hemoglobin concentration was consistent within broods, (ii) hemoglobin concentration of nestlings varied markedly across years, (iii) hemoglobin concentration was significantly higher in the forest study site which is richer in terms of food abundance during the short period of tits breeding season and (iv) high hemoglobin level was a predictor of nestling survival from hatching to fledging.

  19. Abnormal hemoglobin genotypes and ABO and rhesus blood groups associated with HIV infection among HIV-exposed infants in North Western Nigeria

    Directory of Open Access Journals (Sweden)

    Buseri FI


    Full Text Available Fiekumo I Buseri,1 Charity N Okonkwo21Hematology and Blood Transfusion Science Unit, Department of Medical Laboratory Science, Niger Delta University, Wilberforce Island, Bayelsa State, Nigeria; 2Department of Medical Laboratory Sciences, Rivers State University of Science and Technology, Port Harcourt, NigeriaBackground: Hemoglobin genotypes and blood groups have been known to be associated with diseases, but the relationship with human immunodeficiency virus (HIV infection among Nigerian infants is not well known.Objective: This study aims to determine the association between hemoglobin genotypes and blood groups with HIV infection among HIV-exposed Nigerian infants.Methods: This cross-sectional study examined 312 HIV-exposed infants (aged 8–16 months in Sokoto State, Nigeria. HIV screening was performed using the HIV DNA polymerase chain reaction technique on dried blood spots. Hemoglobin electrophoresis and ABO and Rhesus (Rh blood groups were carried out using standard techniques.Results: This study found 20.5% HIV-1 seropositivity among the infants, with 20.9% of males and 20.1% of females positive for HIV-1. Babies' sex and HIV seropositivity was not significant (χ2=0.27, df=1, P=0.869. The blood group distribution was O (43.3%, A (36.8%, B (15.7%, AB (4.2%, RhD+ (95.6%, and RhD– (4.4%. The combined ABO and Rh blood groups among the study population were O+ (40.1%, A+ (36.2%, B+ (15.1%, AB+ (4.2%, O– (3.2%, A– (0.6%, and B– (0.6%. No AB– baby was found. The association between blood groups and HIV seropositivity was not significant (Fisher’s exact test =9.140; P=0.169; however, group AB+ showed the highest probable association with HIV seropositivity (46.2%, followed by A+ (23.9%. The prevalence of hemoglobin genotypes was AA (71.5%, AS (25.3%, AC (2.2%, and SC (1.0%. Hemoglobin SS and other hemoglobin variants were not found. A significant association (χ2=8.432, df=3, P=0.034 was observed between SC and HIV-1 infection

  20. Heterozygote Hemoglobin G-Coushatta as the Cause of a Falsely Decreased Hemoglobin A1C in an Ion-Exchange HPLC Method

    Directory of Open Access Journals (Sweden)

    Kurtoğlu Ayşegül Uğur


    Full Text Available Glycated hemoglobin (HbA1c is used for the assessment of glycemic control in patients with diabetes. The presence of genetic variants of hemoglobin can profoundly affect the accuracy of HbA1c measurement. Here, we report two cases of Hemoglobin G-Coushatta (HBB:c.68A>C variant that interferes in the measurement of HbA1c by a cation-exchange HPLC (CE-HPLC method. HbA1c was measured by a CE-HPLC method in a Tosoh HLC-723 G7 instrument. The HbA1c levels were 2.9% and 4%. These results alerted us to a possible presence of hemoglobinopathy. In the hemoglobin variant analysis, HbA2 levels were detected as 78.3% and 40.7% by HPLC using the short program for the Biorad Variant II. HbA1c levels were measured by an immunoturbidimetric assay in a Siemens Dimension instrument. HbA1c levels were reported as 5.5% and 5.3%. DNA mutation analysis was performed to detect the abnormal hemoglobin variant. Presence of Hemoglobin G-Coushatta variant was detected in the patients. The Hb G-Coushatta variants have an impact on the determination of glycated hemoglobin levels using CEHPLC resulting in a false low value. Therefore, it is necessary to use another measurement method.

  1. Analysis of Swine Leukocyte Antigen Peptide Binding Profiles and the Identification of T cell Epitopes by Tetramer Staining

    DEFF Research Database (Denmark)

    Pedersen, Lasse Eggers

    of the specific CTL response elicited as a result of immunization against foot-and-mouth-disease virus (FMDV) and swine influenza A virus. These studies resulted in the identification of T cell epitopes from both viruses. As SLA:peptide binding data accumulates in these and similar studies, it becomes possible...... class I peptide binding characteristics in relation to immune responses to vaccination or infection. Applying proven technologies to newly produced, recombinant swine leukocyte antigen (SLA) class I proteins yielded a body of data for peptide:SLA:β2m (pSLA) complex affinity and stability. Mapping...... for collaborators at Center for Biological Sequence Analysis (CBS), DTU, to further strengthen the NetMHCpan algorithm. This prediction tool now has the capacity for the selection of peptide candidates to be bound by human (HLA), bovine (bovine leukocyte antigen (BoLA)) and swine (SLA) MHC proteins. Expanding...

  2. Broadband diffuse optical spectroscopy assessment of hemorrhage- and hemoglobin-based blood substitute resuscitation (United States)

    Lee, Jangwoen; Kim, Jae G.; Mahon, Sari; Tromberg, Bruce J.; Mukai, David; Kreuter, Kelly; Saltzman, Darin; Patino, Renee; Goldberg, Robert; Brenner, Matthew


    Hemoglobin-based oxygen carriers (HBOCs) are solutions of cell-free hemoglobin (Hb) that have been developed for replacement or augmentation of blood transfusion. It is important to monitor in vivo tissue hemoglobin content, total tissue hemoglobin [THb], oxy- and deoxy-hemoglobin concentrations ([OHb], [RHb]), and tissue oxygen saturation (StO2=[OHb]/[THb]×100%) to evaluate effectiveness of HBOC transfusion. We designed and constructed a broadband diffuse optical spectroscopy (DOS) prototype system to measure bulk tissue absorption and scattering spectra between 650 and 1000 nm capable of accurately determining these tissue hemoglobin component concentrations in vivo. Our purpose was to assess the feasibility of using DOS to optically monitor tissue [OHb], [RHb], StO2, and total tissue hemoglobin concentration ([THb]=[OHb]+[RHb]) during HBOC infusion using a rabbit hypovolemic shock model. The DOS prototype probe was placed on the shaved inner thigh muscle of the hind leg to assess concentrations of [OHb], [RHb], [THb], as well as StO2. Hemorrhagic shock was induced in intubated New Zealand white rabbits (N=6) by withdrawing blood via a femoral arterial line to 20% blood loss (10-15 cc/kg). Hemoglobin glutamer-200 (Hb-200) 1:1 volume resuscitation was administered following the hemorrhage. These values were compared against traditional invasive measurements, serum hemoglobin concentration (sHGB), systemic blood pressure, heart rate, and blood gases. DOS revealed increases of [THb], [OHb], and tissue hemoglobin oxygen saturation after Hb-200 infusion, while blood total hemoglobin values continued did not increase; we speculate, due to hyperosmolality induced hemodilution. DOS enables noninvasive in vivo monitoring of tissue hemoglobin and oxygenation parameters during shock and volume expansion with HBOC and potentially enables the assessment of efficacy of resuscitation efforts using artificial blood substitutes.

  3. Structural and redox behavior of OxyVita, a zero-linked polymeric hemoglobin: comparison with natural acellular polymeric hemoglobins. (United States)

    Harrington, John P; Orlik, Kseniya; Orlig, Kseniya; Zito, Samantha L; Wollocko, Jacek; Wollocko, Hanna


    A zero-linked polymeric hemoglobin (OxyVita Hb) has been developed for application as an acellular therapeutic hemoglobin-based-oxygen-carrier (HBOC). For effective and safe oxygen binding, transport and delivery, an HBOC must meet essential molecular requirements related to its structural integrity and redox stability. OxyVita is a super polymer possessing an average M.wt. of 17 x 10(6) Da. Structural integrity was determined by unfolding studies of OxyVita in the presence of increasing concentrations of urea. The unfolding midpoints (D(1/2)) of different preparations of OxyVita (solution and powder forms) were compared to Lumbricus Hb (LtHb) and Arenicola Hb (ArHb), natural acellular polymeric hemoglobins, which are serving as models for an effective and safe acellular HBOC. Reduction studies of OxyVita Hb using endogenous reducing agents were also investigated. Results from these studies indicate that: 1) OxyVita Hb exhibits greater resistance to conformational change than either LtHb or ArHb in the reduced (oxyHb) state; and 2) the reduction of met OxyVita Hb to oxyHb occurs slowly in the presence of either ascorbic acid (70% reduction in 560 min.) or beta-NADH (40% reduction in 90 min.). These studies provide consistent evidence that OxyVita Hb possesses physiochemical properties that exhibit structural integrity and redox behavior necessary for functioning as an effective and safe HBOC within clinical applications. These results are in agreement with observations made by other investigators as to the reduction in heme-loss of OxyVita Hb, essential for the reversible binding/release of molecular oxygen within the circulatory system.

  4. Vitreoscilla hemoglobin gene ( vgb) improves lutein production in Chlorella vulgaris (United States)

    Ma, Ruijuan; Lin, Xiangzhi


    Vitreoscilla hemoglobin is an oxygen-binding protein that promotes oxygen delivery and reduces oxygen consumption under low oxygen conditions to increase the efficiency of cell respiration and metabolism. In this study, we introduced a Vitreoscilla hemoglobin gene ( vgb) into Chlorella vulgaris by Agrobacterium tumefaciens -mediated transformation (ATMT). PCR analysis confirmed that the vgb gene was successfully integrated into the Chlorella vulgaris genome. Analysis of biomass obtained in shake flasks revealed transformant biomass concentrations as high as 3.28 g/L, which was 38.81% higher than that of the wild-type strain. Lutein content of transformants also increased slightly. Further experiments recovered a maximum lutein yield of 2.91 mg/L from the transformants, which was 36.77% higher than that of the wild-type strain. The above results suggest that integrated expression of the vgb gene may improve cell growth and lutein yield in Chlorella vulgaris, with applications to lutein production from Chlorella during fermentation.

  5. Hypoxia adaptation and hemoglobin mutation in Tibetan chick embryo

    Institute of Scientific and Technical Information of China (English)

    GOU Xiao; LI Ning; LIAN Linsheng; YAN Dawei; ZHANG Hao; WU Changxin


    Tibetan chick lives at high altitudes between 2600 and 4200 m with a high hatchability and low land breeds survive rarely with a hatchability of 3.0% under hypoxia of simulated 4200 m. Under hypoxia of whole 21 d, the hatchability of Tibetan chick and Recessive White Feather broiler differed with a greatest disparity from day 4 to 11 and also significantly in other stages except from day 1 to 3. Hypoxia in each stage did not reduce significantly survival rate of this stage except hatchability. These two results indicated that the hypoxia in the early stage had an adverse effect on the later stage. All exons encoding chick hemoglobins were sequenced to analyze gene polymorphism. The functional mutation Met-32(B13)-Leu, related with hypoxia, was found in αD globin chain and the mutation frequency increased with increased altitude. In addition, under hypoxic conditions, the population with higher mutation frequency had a higher hatchability. The automated homology model building was carried out using crystal structure coordinates of chick HbD. The results indicated that the substitution Met-32(B13)-Leu provides a more hydrophobic environment which leads to higher stability of heme and oxygen affinity of hemoglobin. The occurrence of the mutation Met-32(B13)-Leu is related to the origin of Tibetan chick.

  6. Biphasic oxidation of oxy-hemoglobin in bloodstains.

    Directory of Open Access Journals (Sweden)

    Rolf H Bremmer

    Full Text Available BACKGROUND: In forensic science, age determination of bloodstains can be crucial in reconstructing crimes. Upon exiting the body, bloodstains transit from bright red to dark brown, which is attributed to oxidation of oxy-hemoglobin (HbO(2 to met-hemoglobin (met-Hb and hemichrome (HC. The fractions of HbO(2, met-Hb and HC in a bloodstain can be used for age determination of bloodstains. In this study, we further analyze the conversion of HbO(2 to met-Hb and HC, and determine the effect of temperature and humidity on the conversion rates. METHODOLOGY: The fractions of HbO(2, met-Hb and HC in a bloodstain, as determined by quantitative analysis of optical reflectance spectra (450-800 nm, were measured as function of age, temperature and humidity. Additionally, Optical Coherence Tomography around 1300 nm was used to confirm quantitative spectral analysis approach. CONCLUSIONS: The oxidation rate of HbO(2 in bloodstains is biphasic. At first, the oxidation of HbO(2 is rapid, but slows down after a few hours. These oxidation rates are strongly temperature dependent. However, the oxidation of HbO(2 seems to be independent of humidity, whereas the transition of met-Hb into HC strongly depends on humidity. Knowledge of these decay rates is indispensable for translating laboratory results into forensic practice, and to enable bloodstain age determination on the crime scene.

  7. Thalassemia and Hemoglobin E in Southern Thai Blood Donors

    Directory of Open Access Journals (Sweden)

    Manit Nuinoon


    Full Text Available Thalassemia and hemoglobin E (Hb E are common in Thailand. Individuals with thalassemia trait usually have a normal hemoglobin concentration or mild anemia. Therefore, thalassemic individuals who have minimum acceptable Hb level may be accepted as blood donors. This study was aimed at determining the frequency of α-thalassemia 1 trait, β-thalassemia trait, and Hb E-related syndromes in Southern Thai blood donors. One hundred and sixteen voluntary blood donors, Southern Thailand origin, were recruited for thalassemia and Hb E screening by red blood cell indices/dichlorophenolindophenol precipitation test. β-Thalassemia and Hb E were then identified by high performance liquid chromatography and 4 common α-thalassemia deletions were characterized by a single tube-multiplex gap-polymerase chain reaction. Overall frequency of hemoglobinopathies was 12.9%, classified as follows: homozygous α-thalassemia 2 (1.7%, heterozygous α-thalassemia 1 (1.7%, heterozygous β-thalassemia without α-thalassemia (0.9%, heterozygous Hb E without α-thalassemia (5.2%, double heterozygotes for Hb E/α-thalassemia 1 (1.7%, homozygous Hb E without α-thalassemia (0.9%, and homozygous Hb E with heterozygous α-thalassemia 2 (0.9%. The usefulness of thalassemia screening is not only for receiving highly effective red blood cells in the recipients but also for encouraging the control and prevention program of thalassemia in blood donors.

  8. Autofluorescence characterization of advanced glycation end products of hemoglobin. (United States)

    Vigneshwaran, Nadanathangam; Bijukumar, Gopalakrishnapillai; Karmakar, Nivedita; Anand, Sneh; Misra, Anoop


    This article describes the analysis of autofluorescence of advanced glycation end products of hemoglobin (Hb-AGE). Formed as a result of slow, spontaneous and non-enzymatic glycation reactions, Hb-AGE possesses a characteristic autofluorescence at 308/345 nm (lambda(ex)/lambda(em)). Even in the presence of heme as a quenching molecule, the surface presence of the glycated adduct gave rise to autofluorescence with the quantum yield of 0.19. The specificity of monoclonal antibody developed against common AGE structure with Hb-AGE was demonstrated using reduction in fluorescence polarization value due to increased molecular volume while binding. The formation of fluorescent adduct in hemoglobin in the advanced stage of glycation and the non-fluorescent HbA(1c) will be of major use in distinguishing and to know the past status of diabetes mellitus. While autofluorescence correlated highly with HbA(1c) value under in vivo condition (r = 0.85), it was moderate in the clinical samples (r = 0.55). The results suggest a non-linear relation between glycemia and glycation, indicating the application of Hb-AGE as a measure of susceptibility to glycation rather than glycation itself.

  9. Hemoglobin glycation rate constant in non-diabetic Individuals. (United States)

    Ladyżyński, Piotr; Wójcicki, Jan M; Bąk, Marianna I; Sabalińska, Stanisława; Kawiak, Jerzy; Foltyński, Piotr; Krzymień, Janusz; Karnafel, Waldemar


    The objectives were as follows: (1) estimating mean value of the overall hemoglobin glycation rate constant (k); (2) analyzing inter-individual variability of k; (3) verifying ability of the hemoglobin A1c (HbA1c) formation model to predict changes of HbA1c during red blood cells cultivation in vitro and to reproduce the clinical data. The mean k estimated in a group of 10 non-diabetic subjects was equal to 1.257 ± 0.114 × 10(-9) L mmol(-1) s(-1). The mean k was not affected by a way of estimation of glycemia. The mean k differed less than 20% from values reported earlier and it was almost identical to the mean values calculated on basis of the selected published data. Analysis of variability of k suggests that inter-individual heterogeneity of HbA1c formation is limited or rare. The HbA1c mathematical model was able to predict changes of HbA1c in vitro resulting from different glucose levels and to reproduce a linear relationship of HbA1c and average glucose obtained in the A1C-Derived Average Glucose Study. This study demonstrates that the glycation model with the same k value might be used in majority of individuals as a tool supporting interpretation of HbA1c in different clinical situations.

  10. Hemoglobin optimization and transfusion strategies in patients undergoing cardiac surgery

    Institute of Scientific and Technical Information of China (English)

    Mahdi; Najafi; David; Faraoni


    Although red blood cells(RBCs) transfusion is sometimes associated with adverse reactions,anemia could also lead to increased morbidity and mortality in highrisk patients. For these reasons,the definition of perioperative strategies that aims to detect and treat preoperative anemia,prevent excessive blood loss,and define "optimal" transfusion algorithms is crucial. Although the treatment with preoperative iron and erythropoietin has been recommended in some specific conditions,several controversies exist regarding the benefit-to-risk balance associated with these treatments. Further studies are needed to better define the indications,dosage,and route of administration for preoperative iron with or without erythropoietin supplementation. Although restrictive transfusion strategies in patients undergoing cardiac surgery have been shown to effectively reduce the incidence and the amount of RBCs transfusion without increase in side effects,some high-risk patients(e.g.,symptomatic acute coronary syndrome) could benefit from higher hemoglobin concentrations. Despite all efforts made last decade,a significant amount of work remains to be done to improve hemoglobin optimization and transfusion strategies in patients undergoing cardiac surgery.

  11. [Minor beta thalassemia masked by a hemoglobin A2 mutant]. (United States)

    Omar, Souheil; Hammami, Mohamed Bassem; Taeib, Sameh Haj; Feki, Moncef; Abbes, Salem; Kaabachi, Naziha


    The elevation of hemoglobin A2 (HbA2) is an essential criterion in the diagnosis of minor ss thalassemia. To report a case of minor ss thalassemia HbA2 with normal HbA2 rate. We report the case of ten years old boy, with hypochromic microcytic anemia, refractory to iron treatment. The study of hemoglobin (Hb) has revealed the presence of a minor abnormal fraction of Hb, amounted to 2.8%, associated with the presence of HbF and normal levels of HbA2. Family study revealed the presence of two Hb abnormalities (ss thalassemia trait and HbA2 mutant) transmitted to offspring in isolation or associated. The genotypic study confirmed the presence of minor, 0 thalassemia and a ⁰/₀₀ gene mutation, causing a new mutant HbA2 named HbA2 Pasteur-Tunis [⁰/₀₀ 59(E3)LysgAsn(AAGgAAC)]. The presence of ⁰/₀₀ mutant reduces HbA2 level and could hide ss thalassemia trait. Rigorous and methodical interpretation of phenotypic data is crucial to not overlook the presence of ss thalassemia trait, whose diagnosis is crucial for genetic counseling and prenatal diagnosis.

  12. Screening for Structural Hemoglobin Variants in Bahia, Brazil

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    Wellington Santos Silva


    Full Text Available Brazil was the country that received the largest number of Africans during the time of colonization, and Bahia was the Brazilian state that received the largest number of slaves from Africa. The purpose of this study was to evaluate the coverage of the newborn screening program for sickle cell disease in the Recôncavo Baiano region of the state of Bahia, and to show the frequency of the subjects with hemoglobin variants in the 2006–2009 period. Blood samples from neonates in twelve cities in the Recôncavo Baiano region were analyzed by High Performance Liquid Chromatography. A total of 16,402 children were born in this period, 14,773 of which underwent newborn screening. In this period 1416 children were born carrying hemoglobin variants HbS and HbC. Forty-seven patients—20 HbSS genotype and 27 HbSC genotype—were diagnosed in eleven of the twelve cities surveyed. The proportion of children born with sickle cell disease in the Recôncavo Baiano region was 1/314, which was higher than the 1/650 rate for the state of Bahia. The data presented in this study confirm the high frequency of sickle cell disease in Recôncavo Baiano, demonstrating the need to create a referral center for the care of patients with sickle cell diseases in the region.

  13. Carbon Monoxide Binding by Hemoglobin and Myoglobin under Photodissociating Conditions (United States)

    Brunori, Maurizio; Bonaventura, Joseph; Bonaventura, Celia; Antonini, Eraldo; Wyman, Jeffries


    Carbon monoxide binding by myoglobin and hemoglobin has been studied under conditions of constant illumination. For hemoglobin, the homotropic heme-heme interaction (cooperativity) and the heterotropic Bohr effect are invariant with light intensity over a 1000-fold change of c½. The dissociation constant, measured as c½, increases linearly with light intensity, indicating that photodissociation is a one-quantum process. At sufficiently high illumination the apparent enthalpy of ligand binding becomes positive, although in the absence of light it is known to be negative. This finding indicates that light acts primarily by increasing the “off” constants by an additive factor. The invariance of both cooperativity and Bohr effect raises a perplexing issue. It would appear to demand either that the “off” constants for the various elementary steps are all alike (which is contrary to current ideas) or that the additive factor is in each case proportional to the particular “off” constant to which it is added (a seemingly improbable alternative). PMID:4502938

  14. Red blood cell lifespan, erythropoiesis and hemoglobin control. (United States)

    Kruse, Anja; Uehlinger, Dominik E; Gotch, Frank; Kotanko, Peter; Levin, Nathan W


    Erythropoietin (EPO) and iron deficiency as causes of anemia in patients with limited renal function or end-stage renal disease are well addressed. The concomitant impairment of red blood cell (RBC) survival has been largely neglected. Properties of the uremic environment like inflammation, increased oxidative stress and uremic toxins seem to be responsible for the premature changes in RBC membrane and cytoskeleton. The exposure of antigenic sites and breakdown of the phosphatidylserine asymmetry promote RBC phagocytosis. While the individual response to treatment with EPO-stimulating agents (ESA) depends on both the RBC's lifespan and the production rate, uniform dosing algorithms do not meet that demand. The clinical use of mathematical models predicting ESA-induced changes in hematocrit might be greatly improved once independent estimates of RBC production rate and/or lifespan become available, thus making the concomitant estimation of both parameters unnecessary. Since heme breakdown by the hemoxygenase pathway results in carbon monoxide (CO) which is exhaled, a simple CO breath test has been used to calculate hemoglobin turnover and therefore RBC survival and lifespan. Future research will have to be done to validate and implement this method in patients with kidney failure. This will result in new insights into RBC kinetics in renal patients. Eventually, these findings are expected to improve our understanding of the hemoglobin variability in response to ESA.

  15. The entropically favored osmotic "compression" of sickle cell hemoglobin gels. (United States)

    Chik, J K; Parsegian, V A


    Contrary to the accurate, hard-sphere depiction of monomeric hemoglobin in solution, sickle cell hemoglobin (HbS) polymerization/gelation requires attention to molecular interactions. From the temperature dependence of the osmotic compressibility of HbS gels, we were able to extract the entropy increase for concentrating HbS in this phase. Normalized per mole of water removed, the entropy increase from gel compression DeltaS(gel) is four times the previously measured DeltaS(trans), for the transition from monomeric HbS solution to HbS gel. The positive entropy change cannot emerge from the assembly of hard spheres but can indicate remodeling of HbS fibers driven by release of ordered water. The fourfold difference in DeltaS(gel) and DeltaS(trans) suggests that the act of initial fiber/gel formation from monomeric solution differs from the process of further polymerization due to tighter packing within the gel phase. Copyright 2001 John Wiley & Sons, Inc. Biopolymers 59: 120-124, 2001

  16. Fetal hemoglobin in sickle cell anemia: a glass half full? (United States)

    Steinberg, Martin H; Chui, David H K; Dover, George J; Sebastiani, Paola; Alsultan, Abdulrahman


    Fetal hemoglobin (HbF) modulates the phenotype of sickle cell anemia by inhibiting deoxy sickle hemoglobin (HbS) polymerization. The blood concentration of HbF, or the number of cells with detectable HbF (F-cells), does not measure the amount of HbF/F-cell. Even patients with high HbF can have severe disease because HbF is unevenly distributed among F-cells, and some cells might have insufficient concentrations to inhibit HbS polymerization. With mean HbF levels of 5%, 10%, 20%, and 30%, the distribution of HbF/F-cell can greatly vary, even if the mean is constant. For example, with 20% HbF, as few as 1% and as many as 24% of cells can have polymer-inhibiting, or protective, levels of HbF of ∼10 pg; with lower HbF, few or no protected cells can be present. Only when the total HbF concentration is near 30% is it possible for the number of protected cells to approach 70%. Rather than the total number of F-cells or the concentration of HbF in the hemolysate, HbF/F-cell and the proportion of F-cells that have enough HbF to thwart HbS polymerization is the most critical predictor of the likelihood of severe sickle cell disease.

  17. Tyrosine can protect against oxidative stress through ferryl hemoglobin reduction. (United States)

    Lu, Naihao; He, Yingjie; Chen, Chao; Tian, Rong; Xiao, Qiang; Peng, Yi-Yuan


    The toxic mechanism of hemoglobin (Hb) under oxidative stress is linked to the formations of highly cytotoxic ferryl species and subsequently heme-to-protein cross-linked derivative of Hb (Hb-X). In this study, we have examined the effects of free tyrosine and its analogues (3-chlorotyrosine, phenylalanine) on the stability of ferryl hemoglobin and the formation of Hb-X. The results showed that free tyrosine (not phenylalanine, 10-500 μM) was an efficient reducing agent of ferryl species and also effective at preventing the formation of cytotoxic Hb-X. Meanwhile, the dimeric tyrosine was formed as the oxidation product of tyrosine during Hb redox reaction. Compared with free tyrosine, 3-chlorotyrosine, an oxidation product of tyrosine and a proposed biomarker for hypochlorous acid (HOCl) in vivo, exhibited stronger antioxidant properties in Hb-induced oxidative stress, which was consistent with its more efficient ability in the reduction of ferryl species. These results showed that the presence of tyrosine and its derivative in vivo and vitro could ameliorate oxidative damage through ferryl heme reduction. The antioxidant ability, therefore, may provide new insights into the nutritional and physiological significance of free tyrosine with redox active heme proteins-related oxidative stress.

  18. Infant Responsiveness, Alertness, Hemoglobin and Growth in Rural Sidama, Ethiopia (United States)

    Aubuchon-Endsley, Nicki L.; Grant, Stephanie L.; Thomas, David G.; Kennedy, Tay S.; Berhanu, Getenesh; Stoecker, Barbara J.; Hubbs-Tait, Laura; Hambidge, K. Michael


    Several recent studies have supported relations between infant behavior (alertness and responsiveness) and nutrition (e.g. Dempsey 2008, Wachs et al 2005) in addition to investigating infant behavior within the context of changes in iron status over time (e.g. Black et al. 2004, Murray-Kolb & Beard 2009). Existing research is typically limited to investigation of the effects of a single vitamin or mineral and no studies have been found that examined the influence that early alertness and responsiveness have on growth in early infancy, despite the fact that relations between behavior and nutritional status may be bidirectional (Hulthén 2003). The current study used a sample of Ethiopian infants and investigated anthropometrics, hemoglobin, the frequency of alertness, and the frequency of responsiveness at 6 and 9 months of age. Six-month weight-for-age predicted 9-month frequency of alertness, while 6-month hemoglobin predicted 9-month frequency of responsiveness. Compared to responsive infants, non-responsive infants at 6 months remained more non-responsive at 9 months, though weight-for-age for both groups converged at 9 months. Results support relations between nutrition and behavior (alertness and responsiveness) and provide evidence of a potentially useful tool (the Laboratory Temperament Assessment Battery [Lab-TAB]) that was adapted to evaluate these relations in Ethiopia. PMID:22233352

  19. Comparative Plasma Protein Profiling of Hemoglobin H Disease

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    Kamonlak Leecharoenkiat


    Full Text Available HbH and HbH-constant spring (HbH-CS are the most common forms of α-thalassemia detected in the Thai population. The accumulation of excess β globin chains in these diseases results in increased red cell hemolysis, and patients with HbH-CS normally have a more severe clinical presentation than patients with HbH disease. This study aimed to detect alterations in the expression of plasma proteins of HbH and HbH-CS patients as compared to normal plasma. Platelet poor plasma was separated from HbH and HbH-CS and normal subjects and differential plasma proteins were detected using two-dimensional gel electrophoresis and identified using LC/MS/MS. A total of 14 differentially expressed proteins were detected of which 5 proteins were upregulated and 9 were downregulated. Most of the differentially expressed proteins are liver secreted proteins involved in hemolysis, oxidative stress response, and hemoglobin degradation. Seven proteins were found to be differentially expressed between HbH and HbH-CS. Levels of haptoglobin, a hemoglobin scavenging protein, were significantly increased in HbH patients as compared to HbH-CS patients. The identification of differentially expressed proteins may lead to a better understanding of the biological events underlying the clinical presentation of HbH and HbH-CS patients and can have application as hemolytic markers or severity predictors.

  20. [Hemoglobin beta S haplotype in the Kebili region (southern Tunisia)]. (United States)

    Frikha, M; Fakhfakh, F; Mseddi, S; Gargouri, J; Ghali, L; Labiadh, Z; Harrabi, M; Souissi, T; Ayadi, H


    Sickle cell anemia is a monogenic hereditary disease characterized by a mutation in the beta globin gene. Five major haplotypes associated with the beta S mutation have been defined: Benin, Bantu, Senegalian, Camerounian, and Arabo-Indian. Previous studies in northern Tunisia showed that sickle cell anemia was of Benin origin in this region. Patients from the south of Tunisia, mainly from the Kebili region, were not previously concerned. In this study, we have determined the beta S haplotype and evaluated phenotypical expression of the disease in 14 patients from this latter region. The use of four restriction endonucleases having polymorphic sites in the beta globin gene showed that all patients had the Benin haplotype, confirming the Benin origin of sickle cell anemia in Tunisia. This haplotype is associated with an heterogeneous expression of fetal hemoglobin (HbF) with extremes varying from 2.4 to 16.3% and a mean expression rate of 8.16%, which is in accordance with literature data. In spite of the haplotype homogeneity in our patients, clinical heterogeneity was noted. A unique case of alpha-thalassemia could not explain this heterogeneity. In contrast, we found a certain correlation between fetal hemoglobin expression and clinical severity.