The Experts below are selected from a list of 1074 Experts worldwide ranked by ideXlab platform
Manfred K Grieshaber - One of the best experts on this subject based on the ideXlab platform.
-
redox regulation of mitochondrial sulfide oxidation in the lugworm Arenicola Marina
The Journal of Experimental Biology, 2008Co-Authors: Tatjana M Hildebrandt, Manfred K GrieshaberAbstract:SUMMARY Sulfide oxidation in the lugworm, Arenicola Marina (L.), is most likely localized in the mitochondria, which can either produce ATP with sulfide as a substrate or detoxify it via an alternative oxidase. The present study identified selective activators of the energy-conserving and the detoxifying sulfide oxidation pathways respectively. In the presence of the ROS scavengers glutathione (GSH) and ascorbate, isolated lugworm mitochondria rapidly oxidized up to 100 μmoll –1 sulfide with maximal oxygen consumption rates but did not produce any ATP in the process. Under these conditions, salicylhydroxamic acid (SHAM), which is an inhibitor of the alternative oxidase of plant mitochondria, completely blocked oxygen consumption whereas inhibitors of complex III and IV had hardly any effect. By contrast, dehydroascorbate (DHA) enabled the mitochondria to gain ATP from sulfide oxidation even if the sulfide concentration far exceeded the threshold for inhibition of cytochrome oxidase. In the presence of dehydroascorbate, respiratory rates were independent of sulfide concentrations, with a respiratory control ratio of 2.1±0.2, and both oxygen consumption and ATP production were completely inhibited by myxothiazol and sodium azide but only marginally by SHAM. The present data indicate that a redox mechanism may contribute to the regulation of sulfide oxidation in lugworm mitochondria in vivo . Thus, mitochondria are presumably much more sulfide resistant in a cellular context than previously thought.
-
ventilatory and metabolic responses to hypoxia and sulphide in the lugworm Arenicola Marina l
The Journal of Experimental Biology, 2000Co-Authors: Stephanie E Wohlgemuth, A C Taylor, Manfred K GrieshaberAbstract:We examined the effects of hypoxia and sulphide levels on the ventilatory activity of Arenicola Marina and determined whether ventilation compensates for oxygen deficiency and affects the mode of energy provision. A. Marina ventilated intermittently, irrespective of ambient P(O2) and sulphide concentration. The ventilation rate was 28.5+/−16 ml h(−1) g(−1) wet mass during normoxia, but increased to 175+/−60% of this value during moderate hypoxia, during which aerobic energy metabolism was maintained. Below a P(O2) of 6.2 kPa, A. Marina reduced the ventilated volume to 54+/−16% of the normoxic value and became anaerobic, as indicated by the accumulation of succinate and strombine. Incubation with 27 micromol l(−1) ambient sulphide had no effect on the normoxic and hypoxic ventilation rates or on the P(O2) below which anaerobiosis started (P(cM)). Increased sulphide concentrations reduced the ventilation rate and shifted the P(cM) towards a higher P(O2) below 10.7 kPa. Sulphide diffused into the body and was at least partially detoxified to thiosulphate when oxygen was present. Under normoxia, sulphide accumulated in the body wall tissue and coelomic fluid when ambient sulphide levels exceeded 117 micromol l(−1) and 216 micromol l(−1), respectively. A decrease in P(O2) in the presence of 27 or 117 micromol l(−1) ambient sulphide had no significant effect on sulphide accumulation.
-
oxygen consumption and sulfide detoxification in the lugworm Arenicola Marina l at different ambient oxygen partial pressures and sulfide concentrations
Journal of Comparative Physiology B-biochemical Systemic and Environmental Physiology, 1997Co-Authors: Kerstin Hauschild, Manfred K GrieshaberAbstract:The lugworm Arenicola Marina is a typical inhabitant of intertidal flats. In its L-shaped burrow the animal is exposed to varying concentrations of O2 and toxic sulfide depending on the tides. The lugworm is able to detoxify sulfide through its oxidation to thiosulfate. When exposed to declining O2 tensions Arenicola Marina reacted as an oxyconformer. In the presence of 25 μmol · l−1 sulfide the respiration was not affected. In contrast, the lugworm consumed significantly less O2 at any Po2 in the presence of 200 μmol · l−1 sulfide. Without sulfide anaerobic metabolism started at a Po2 of approximatedly 10 kPa. Even at high O2 tensions animals exposed to sulfide produced significantly more anaerobic metabolites compared with the controls. Accordingly the critical value PcM, the ambient Po2 below which anaerobic metabolism starts, was shifted towards normoxia. Since O2 supply was sufficient for aerobic metabolism, anaerobiosis was induced by sulfide. An influx of sulfide was observed at 25 as well as at 200 μmol · l−1 sulfide. The main product of sulfide detoxification in the lugworm was thiosulfate. Its synthesis increased with ambient Po2 and depended on the sulfide concentration. Sulfide and thiosulfate were detected in the coelomic fluid, the blood, and the body wall of Arenicola Marina. Only about 2% of the ambient O2 was used for sulfide detoxification at 25 μmol · l−1 sulfide and about 50% at 200 μmol · l−1 sulfide, respectively. Even at the low sulfide concentration Arenicola Marina's capacity to detoxify sulfide was too low to maintain a complete aerobic metabolism.
-
mitochondrial sulfide oxidation in Arenicola Marina
FEBS Journal, 1996Co-Authors: Susanne Volkel, Manfred K GrieshaberAbstract:Sulfide is oxidized in the mitochondria of the lugworm Arenicola Marina. Mitochondrial sulfide oxidation is coupled with oxygen consumption and with an equimolar production of thiosulfate [Vokel, S. & Grieshaber, M. K. (1994) Mar. Biol. 118, 137–147], Mitochondrial respiration in the presence of malate (or succinate) and ADP but without sulfide could be completely inhibited by rotenone, antimycin, cyanide, and sulfide. Only 40% inhibition was achieved by salicylhydroxamic acid. Sulfide oxidation (with sulfide as the only substrate) was fully inhibited by antimycin and by salicylhydroxamic acid but not by rotenone or sulfide. Moreover, sulfide oxidation was 3–4-fold less sensitive to cyanide as compared to normal respiration. The data indicate that sulfide oxidation in A. Marina is linked to the respiratory electron transport chain. We suggest that electrons from sulfide enter the respiratory chain via ubiquinone or at the ubiquinol–cytochrome-c oxidoreductase. At sulfide concentrations higher than 10 μM, the cyto-chrome-c oxidase is blocked and electrons from sulfide are transferred to oxygen via an alternative terminal oxidase.
-
mitochondrial sulfide oxidation in Arenicola Marina evidence for alternative electron pathways
FEBS Journal, 1996Co-Authors: Susanne Volkel, Manfred K GrieshaberAbstract:Sulfide is oxidized in the mitochondria of the lugworm Arenicola Marina. Mitochondrial sulfide oxidation is coupled with oxygen consumption and with an equimolar production of thiosulfate [Vokel, S. & Grieshaber, M. K. (1994) Mar. Biol. 118, 137–147], Mitochondrial respiration in the presence of malate (or succinate) and ADP but without sulfide could be completely inhibited by rotenone, antimycin, cyanide, and sulfide. Only 40% inhibition was achieved by salicylhydroxamic acid. Sulfide oxidation (with sulfide as the only substrate) was fully inhibited by antimycin and by salicylhydroxamic acid but not by rotenone or sulfide. Moreover, sulfide oxidation was 3–4-fold less sensitive to cyanide as compared to normal respiration. The data indicate that sulfide oxidation in A. Marina is linked to the respiratory electron transport chain. We suggest that electrons from sulfide enter the respiratory chain via ubiquinone or at the ubiquinol–cytochrome-c oxidoreductase. At sulfide concentrations higher than 10 μM, the cyto-chrome-c oxidase is blocked and electrons from sulfide are transferred to oxygen via an alternative terminal oxidase.
Lars Folke Olsen - One of the best experts on this subject based on the ideXlab platform.
-
a combination of dynamic light scattering and polarized resonance raman scattering applied in the study of Arenicola Marina extracellular hemoglobin
Journal of Chemical Physics, 2013Co-Authors: Kit Drescher Jernshoj, Søren Hassing, Lars Folke OlsenAbstract:Arenicola Marina extracellular hemoglobin (Hbl Hb) is considered to be a promising candidate as a blood substitute. To entangle some of the properties of extracellular giant hexagonal bilayer hemoglobin (Hbl Hb) of Arenicola Marina, we combined polarized resonance Raman scattering (532 nm excitation) with dynamic light scattering (DLS) (632.8 nm). An analysis of the depolarization ratio of selected a2g skeletal modes of the heme in native Hbl Hb and porcine Hb, shows that the distortion of the heme group away from its ideal fourfold symmetry is much smaller for heme groups bound in the Hbl Hb than for heme groups bound in porcine Hb. Using DLS, the average hydrodynamic diameter (⟨dh⟩) of Hbl Hb was measured at pH = 5, 7, 8, 9, and 10. At pH = 5 to 7, the Hbl Hb was found in its native form with ⟨dh⟩ equal to 24.2 nm, while at pH = 8 and 9, a dissociation process starts to take place resulting in ⟨dh⟩ = 9 nm. At pH = 10, only large aggregates of fragmented Hbl Hb with ⟨dh⟩ larger than 1000 nm was detected,...
-
a combination of dynamic light scattering and polarized resonance raman scattering applied in the study of Arenicola Marina extracellular hemoglobin
Journal of Chemical Physics, 2013Co-Authors: Kit Drescher Jernshoj, Søren Hassing, Lars Folke OlsenAbstract:Arenicola Marina extracellular hemoglobin (Hbl Hb) is considered to be a promising candidate as a blood substitute. To entangle some of the properties of extracellular giant hexagonal bilayer hemoglobin (Hbl Hb) of Arenicola Marina, we combined polarized resonance Raman scattering (532 nm excitation) with dynamic light scattering (DLS) (632.8 nm). An analysis of the depolarization ratio of selected a2g skeletal modes of the heme in native Hbl Hb and porcine Hb, shows that the distortion of the heme group away from its ideal fourfold symmetry is much smaller for heme groups bound in the Hbl Hb than for heme groups bound in porcine Hb. Using DLS, the average hydrodynamic diameter (⟨d h ⟩) of Hbl Hb was measured at pH = 5, 7, 8, 9, and 10. At pH = 5 to 7, the Hbl Hb was found in its native form with ⟨d h ⟩ equal to 24.2 nm, while at pH = 8 and 9, a dissociation process starts to take place resulting in ⟨d h ⟩ = 9 nm. At pH = 10, only large aggregates of fragmented Hbl Hb with ⟨d h ⟩ larger than 1000 nm was detected, however, a comparison of the DLS results with the polarized resonance Raman scattering (RRS) revealed that the coupling between the fragments did not involve direct interaction between the heme groups, but also that the local heme environment seems to be comparable in the aggregates and in the native Hbl Hb. By comparing the unpolarized RRS results obtained for erythrocytes (RBC) with those for Hbl Hb, led us to the important conclusion that Hbl Hb is much easier photolyzed than porcine RBC.
Lawrence M Mayer - One of the best experts on this subject based on the ideXlab platform.
-
digestive bioavailability to a deposit feeder Arenicola Marina of polycyclic aromatic hydrocarbons associated with anthropogenic particles
Environmental Toxicology and Chemistry, 2004Co-Authors: Ian M Voparil, Lawrence M Mayer, Robert M Burgess, Rex Tien, Mark G Cantwell, Stephen A RybaAbstract:Marine sediments around urban areas serve as catch basins for anthropogenic particles containing polycyclic aromatic hydrocarbons (PAHs). Using incubations with gut fluids extracted from a deposit-feeding polychaete ( Arenicola Marina), we determined the digestive bioavailability of PAHs from fly ashes, coal dusts, diesel soots, tire tread materials, and urban particulates. We found that gut fluids solubilize significant concentrations of PAHs from two tire treads, two diesel soots, and the urban particulates. However, PAHs in fly ashes and coal dusts were not available to the digestive agents in gut fluid. Potential digestive exposure to PAHs is much greater than that predicted to be available from these materials using equilibrium partitioning theory (EqP). Amending an already-contaminated sediment with fly ash decreased phenanthrene solubilization by gut fluid. In contrast, addition of tire tread to the sediment resulted in increased solubilization of four PAHs by gut fluid. Therefore, addition of certain types of anthropogenic particles to sediments may result in an increase in bioavailable PAHs rather than a net decrease, as predicted by EqP. Difficulty in predicting the amount of change due to amendment may be due to interactions occurring among the mixture of compounds solubilized by gut fluid.
-
digestive bioavailability to a deposit feeder Arenicola Marina of polycyclic aromatic hydrocarbons associated with anthropogenic particles
Environmental Toxicology and Chemistry, 2004Co-Authors: Ian M Voparil, Lawrence M Mayer, Robert M Burgess, Rex Tien, Mark G Cantwell, Stephen A RybaAbstract:Marine sediments around urban areas serve as catch basins for anthropogenic particles containing polycyclic aromatic hydrocarbons (PAHs). Using incubations with gut fluids extracted from a deposit-feeding polychaete (Arenicola Marina), we determined the digestive bioavailability of PAHs from fly ashes, coal dusts, diesel soots, tire tread materials, and urban particulates. We found that gut fluids solubilize significant concentrations of PAHs from two tire treads, two diesel soots, and the urban particulates. However, PAHs in fly ashes and coal dusts were not available to the digestive agents in gut fluid. Potential digestive exposure to PAHs is much greater than that predicted to be available from these materials using equilibrium partitioning theory (EqP). Amending an already-contaminated sediment with fly ash decreased phenanthrene solubilization by gut fluid. In contrast, addition of tire tread to the sediment resulted in increased solubilization of four PAHs by gut fluid. Therefore, addition of certain types of anthropogenic particles to sediments may result in an increase in bioavailable PAHs rather than a net decrease, as predicted by EqP. Difficulty in predicting the amount of change due to amendment may be due to interactions occurring among the mixture of compounds solubilized by gut fluid.
-
commercially available chemicals that mimic a deposit feeder s Arenicola Marina digestive solubilization of lipids
Environmental Science & Technology, 2004Co-Authors: Ian M Voparil, Lawrence M MayerAbstract:To develop a simple and cost-effective bioavailability test for sediment-bound contaminants, the solubilization strengths of mixtures of four commercially available surfactants and four proteins were compared to that of digestive fluids from a deposit-feeding benthic polychaete Arenicola Marina. Initial tests indicated that sodium taurocholate, a vertebrate bile salt, was the most accurate mimic of A. Marina gut fluids' solubilization of individual polycyclic aromatic hydrocarbons (PAH). Further testing with nutritional lipids and other hydrophobic contaminants confirmed the similarities of these fluids. Bovine serum albumin (BSA) solubilization of PAH was the most efficient of all the proteins tested. A cocktail of sodium taurocholate and BSA was compared to A. Marina's solubilization of 12 PAH from four different contaminated sediments (from Boston, Charleston, Jacksonville, and San Diego harbors). The two solutions released most PAH to similar extents; 40 of 48 PAH−sediment combinations were released a...
-
commercially available chemicals that mimic a deposit feeder s Arenicola Marina digestive solubilization of lipids
Environmental Science & Technology, 2004Co-Authors: Ian M Voparil, Lawrence M MayerAbstract:To develop a simple and cost-effective bioavailability test for sediment-bound contaminants, the solubilization strengths of mixtures of four commercially available surfactants and four proteins were compared to that of digestive fluids from a deposit-feeding benthic polychaete Arenicola Marina. Initial tests indicated that sodium taurocholate, a vertebrate bile salt, was the most accurate mimic of A. Marina gut fluids' solubilization of individual polycyclic aromatic hydrocarbons (PAH). Further testing with nutritional lipids and other hydrophobic contaminants confirmed the similarities of these fluids. Bovine serum albumin (BSA) solubilization of PAH was the most efficient of all the proteins tested. A cocktail of sodium taurocholate and BSA was compared to A. Marina's solubilization of 12 PAH from four different contaminated sediments (from Boston, Charleston, Jacksonville, and San Diego harbors). The two solutions released most PAH to similar extents; 40 of 48 PAH-sediment combinations were released at amounts within a factor of 2 in cocktail and gut fluid solutions. Therefore, the cocktail may serve as a surrogate for real gut fluids and allow easier adoption of the in vitro incubation approach to bioavailability testing.
-
structures and concentrations of surfactants in gut fluid of the marine polychaete Arenicola Marina
Marine Ecology Progress Series, 2003Co-Authors: J C Smoot, Lawrence M Mayer, Michael J Bock, P Wood, Robert H FindlayAbstract:Marine invertebrate deposit feeders secrete surfactants into their gut fluid in concentra- tions sufficient to induce micelle formation, enhancing solubilization of sedimentary lipids. We iso- lated and identified 3 related surfactant molecules from the deposit-feeding polychaete lugworm Arenicola Marina. Surfactants were isolated and separated by a combination of solvent extraction and thin-layer and gas chromatography. Identification was performed using mass and infrared spec- trometry, coupled to various derivatization and hydrolysis reactions. A. Marina produces a mixture of related yet distinct anionic surfactants composed of branched, C9, saturated and unsaturated fatty acids that are amide linked to leucine or glycine residues, showing some similarity to crustacean sur- factants. The critical micelle concentration of the mixture of these surfactants in gut fluid was about 2 mM, and total concentrations ranged from 5.5 to 19.5 mM. The hydrophilic amide linkage helps to explain previous observations that gut surfactants do not adsorb onto sediment transiting the gut.
Franck Zal - One of the best experts on this subject based on the ideXlab platform.
-
a therapeutic oxygen carrier isolated from Arenicola Marina decreases amanitin induced hepatotoxicity
Toxicon, 2021Co-Authors: Brendan Le Dare, Pierrejean Ferron, Nessrine Bellamri, Catherine Ribault, Eric Delpy, Franck Zal, Vincent Lagente, Thomas GicquelAbstract:The amanitins (namely α- and β-amanitin) contained in certain mushrooms are bicyclic octapeptides that, when ingested, are responsible for potentially lethal hepatotoxicity. M101 is an extracellular hemoglobin extracted from the marine worm Arenicola Marina. It has intrinsic Cu/Zn-SOD-like activity and is currently used as an oxygen carrier in organ preservation solutions. Our present results suggest that M101 might be effective in reducing amanitin-induced hepatotoxicity and may have potential for therapeutic development.
-
therapeutic potential of hemoglobin derived from the marine worm Arenicola Marina m101 a literature review of a breakthrough innovation
Marine Drugs, 2021Co-Authors: Fareeha Batool, Eric Delpy, Franck Zal, Elisabeth Leizezal, Olivier HuckAbstract:Oxygen (O2) is indispensable for aerobic respiration and cellular metabolism. In case of injury, reactive oxygen species are produced, causing oxidative stress, which triggers cell damaging chemical mediators leading to ischemic reperfusion injuries (IRI). Sufficient tissue oxygenation is necessary for optimal wound healing. In this context, several hemoglobin-based oxygen carriers have been developed and tested, especially as graft preservatives for transplant procedures. However, most of the commercially available O2 carriers increase oxidative stress and show some adverse effects. Interestingly, the hemoglobin derived from the marine lugworm Arenicola Marina (M101) has been presented as an efficient therapeutic O2 carrier with potential anti-inflammatory, anti-bacterial, and antioxidant properties. Furthermore, it has demonstrated promise as a supplement to conventional organ preservatives by reducing IRI. This review summarizes the properties and various applications of M101. M101 is an innovative oxygen carrier with several beneficial therapeutic properties, and further research must be carried out to determine its efficacy in the management of different pathologies.
-
a therapeutic oxygen carrier isolated from Arenicola Marina decreased p gingivalis induced inflammation and tissue destruction
Scientific Reports, 2020Co-Authors: Fareeha Batool, Eric Delpy, Franck Zal, Elisabeth Leizezal, Olivier Huck, Celine Stutz, Catherine Petit, Nadia BenkiranejesselAbstract:The control of inflammation and infection is crucial for periodontal wound healing and regeneration. M101, an oxygen carrier derived from Arenicola Marina, was tested for its anti-inflammatory and anti-infectious potential based on its anti-oxidative and tissue oxygenation properties. In vitro, no cytotoxicity was observed in oral epithelial cells (EC) treated with M101. M101 (1 g/L) reduced significantly the gene expression of pro-inflammatory markers such as TNF-α, NF-κΒ and RANKL in P. gingivalis-LPS stimulated and P. gingivalis-infected EC. The proteome array revealed significant down-regulation of pro-inflammatory cytokines (IL-1β and IL-8) and chemokine ligands (RANTES and IP-10), and upregulation of pro-healing mediators (PDGF-BB, TGF-β1, IL-10, IL-2, IL-4, IL-11 and IL-15) and, extracellular and immune modulators (TIMP-2, M-CSF and ICAM-1). M101 significantly increased the gene expression of Resolvin-E1 receptor. Furthermore, M101 treatment reduced P. gingivalis biofilm growth over glass surface, observed with live/dead analysis and by decreased P. gingivalis 16 s rRNA expression (51.7%) (p < 0.05). In mice, M101 reduced the clinical abscess size (50.2%) in P. gingivalis-induced calvarial lesion concomitant with a decreased inflammatory score evaluated through histomorphometric analysis, thus, improving soft tissue and bone healing response. Therefore, M101 may be a novel therapeutic agent that could be beneficial in the management of P. gingivalis associated diseases.
-
high level production of recombinant Arenicola Marina globin chains in escherichia coli a new generation of blood substitute
Artificial Cells Blood Substitutes and Biotechnology, 2009Co-Authors: Thomas Harnois, Morgane Rousselot, Helene Rogniaux, Franck ZalAbstract:This work reports for the first time the expression of a soluble B2 globin chain that is part of the extracellular hexagonal-bilayer haemoglobin from Arenicola Marina. Two recombinant B2 globins were produced, one fused with gluthatione S-tranferase (B2-GST) and the other without a fusion tag (RecB2) and requiring a different purification procedure. We also describe a new method for the expression of globin that uses Studier's auto-induction medium together with the heme precursor delta-aminolevulinic acid. Media supplementation with the heme precursor delta-aminolevulinic acid in the culture increased heme synthesis by E. coli leading to the expression of the recombinant B2 globins in their active form. RecB2 and B2-GST were expressed with a yield of up to 105 mg/l of E. coli culture. Our approach is rapid and requires only one chromatographic purification step for B2-GST and three purification steps for RecB2. The overall results on RecB2 and B2-GST show that the recombinant globins exhibit similar properties to those of Arenicola Marina native HBL-Hb with a great stability and a strong oxygen binding. The results and methodologies described in this paper are the beginning of a work aiming at reconstituting a recombinant HBL-Hb by genetic engineering in order to produce an innovative oxygen carrier for therapeutic applications.
-
Arenicola Marina extracellular hemoglobin: a new promising blood substitute
Biotechnology Journal, 2006Co-Authors: Morgane Rousselot, Eric Delpy, Vincent Lagente, Christophe Drieu La Rochelle, Ralph Pirow, Jean-françois Rees, Agnès Hagège, Dominique Le Guen, Stéphane Hourdez, Franck ZalAbstract:The need to develop a blood substitute is now urgent because of the increasing concern over Europe’s BSE outbreak and the worldwide HIV/AIDS epidemic, which have cut blood supplies. Extracellular soluble hemoglobin has long been studied for its possible use as a safe and effective alternative to blood transfusion, but this has met with little success. Clinical trials have revealed undesirable side effects–oxidative damage and vasoconstriction–that hamper the application of cellfree hemoglobin as a blood substitute. We have addressed these problems and have found a new promising extracellular blood substitute: the natural giant extracellular polymeric hemoglobin of the polychaete annelid Arenicola Marina. Here we show that it is less likely to cause immunogenic response; its functional and structural properties should prevent the side effects often associated with the administration of extracellular hemoglobin. Moreover, its intrinsic properties are of interest for other therapeutic applications often associated with hemorrhagic shock (ischemia reperfusion, treatment of septic shock and for organ preservation prior to transplantation). Moreover, using natural hemoglobin is particularly useful since recombinant DNA techniques could be used to express the protein in large quantities.
Kit Drescher Jernshoj - One of the best experts on this subject based on the ideXlab platform.
-
a combination of dynamic light scattering and polarized resonance raman scattering applied in the study of Arenicola Marina extracellular hemoglobin
Journal of Chemical Physics, 2013Co-Authors: Kit Drescher Jernshoj, Søren Hassing, Lars Folke OlsenAbstract:Arenicola Marina extracellular hemoglobin (Hbl Hb) is considered to be a promising candidate as a blood substitute. To entangle some of the properties of extracellular giant hexagonal bilayer hemoglobin (Hbl Hb) of Arenicola Marina, we combined polarized resonance Raman scattering (532 nm excitation) with dynamic light scattering (DLS) (632.8 nm). An analysis of the depolarization ratio of selected a2g skeletal modes of the heme in native Hbl Hb and porcine Hb, shows that the distortion of the heme group away from its ideal fourfold symmetry is much smaller for heme groups bound in the Hbl Hb than for heme groups bound in porcine Hb. Using DLS, the average hydrodynamic diameter (⟨dh⟩) of Hbl Hb was measured at pH = 5, 7, 8, 9, and 10. At pH = 5 to 7, the Hbl Hb was found in its native form with ⟨dh⟩ equal to 24.2 nm, while at pH = 8 and 9, a dissociation process starts to take place resulting in ⟨dh⟩ = 9 nm. At pH = 10, only large aggregates of fragmented Hbl Hb with ⟨dh⟩ larger than 1000 nm was detected,...
-
a combination of dynamic light scattering and polarized resonance raman scattering applied in the study of Arenicola Marina extracellular hemoglobin
Journal of Chemical Physics, 2013Co-Authors: Kit Drescher Jernshoj, Søren Hassing, Lars Folke OlsenAbstract:Arenicola Marina extracellular hemoglobin (Hbl Hb) is considered to be a promising candidate as a blood substitute. To entangle some of the properties of extracellular giant hexagonal bilayer hemoglobin (Hbl Hb) of Arenicola Marina, we combined polarized resonance Raman scattering (532 nm excitation) with dynamic light scattering (DLS) (632.8 nm). An analysis of the depolarization ratio of selected a2g skeletal modes of the heme in native Hbl Hb and porcine Hb, shows that the distortion of the heme group away from its ideal fourfold symmetry is much smaller for heme groups bound in the Hbl Hb than for heme groups bound in porcine Hb. Using DLS, the average hydrodynamic diameter (⟨d h ⟩) of Hbl Hb was measured at pH = 5, 7, 8, 9, and 10. At pH = 5 to 7, the Hbl Hb was found in its native form with ⟨d h ⟩ equal to 24.2 nm, while at pH = 8 and 9, a dissociation process starts to take place resulting in ⟨d h ⟩ = 9 nm. At pH = 10, only large aggregates of fragmented Hbl Hb with ⟨d h ⟩ larger than 1000 nm was detected, however, a comparison of the DLS results with the polarized resonance Raman scattering (RRS) revealed that the coupling between the fragments did not involve direct interaction between the heme groups, but also that the local heme environment seems to be comparable in the aggregates and in the native Hbl Hb. By comparing the unpolarized RRS results obtained for erythrocytes (RBC) with those for Hbl Hb, led us to the important conclusion that Hbl Hb is much easier photolyzed than porcine RBC.