Photodecomposition might be regarded as one of the most important abiotic factors affecting the fate of UV absorbing compounds in the environment and photocatalysis has been suggested as an effective method to degrade organic pollutants. However, UV filters transformation appears to be a complex process, barely addressed to date. The ...

The oriental fruit fly, Bactrocera dorsalis, is an economically damaging, polyphagous pest of fruit crops in South-East Asia and Hawaii, and a quarantine pest in other parts of the world. The objective of our study was to identify new attractants for B. dorsalis from overripe mango fruits. Headspace samples of ...

The purpose of this work was to evaluate some new filtration systems in relation to the quality of extra-virgin olive oil (EVOO). Filtration processes were undertaken in a pilot plan using polypropylene filter bag and two different inert gas flow as filter aids (argon and nitrogen). Qualitative and quantitative variations ...

Thioarsenates dominate arsenic speciation in sulfidic geothermal waters, yet little is known about their fate in the environment. At Conch Spring, an alkaline hot spring in Yellowstone National Park, trithioarsenate transforms to arsenate under increasingly oxidizing conditions along the drainage channel, accompanied by an initial increase, then decrease of monothioarsenate ...

The products of ligation reaction of a 24 nucleotides long PolyA RNA adsorbed on mica were observed by atomic force microscopy. The occurrence of oligonucleotides at different degrees of polymerization has been quantitatively studied before and after ligation reaction. The microscopy images at the nanoscale show that nonenzymatic ligation of ...

Modular synthesis of vinyl and fluorovinyl triazoles can be achieved from bifunctional propargyl and fluoropropargyl sulfones by Cu-catalyzed azide-alkyne ligation and Julia-Kocienski olefination. Competitive click reactions of the protio and fluoropropargyl sulfones show higher reactivity of the latter, and a preliminary DFT analysis was performed.

Periodate modification of the sugar moiety in sugars, including adenosine triphosphate (ATP), has previously been employed in order to prepare dialdehyde-type reagents, which were then utilized in crosslinking reactions on haemoglobin, yielding polymerized material with useful dioxygen-binding properties and hence proposed as possible artificial oxygen carriers ('blood substitutes'). Here, the ...

Nitrite (NO₂⁻), now regarded as an endocrine reserve of nitric oxide (NO), is bioactivated by nitrite reductase enzymes to mediate physiological responses. In blood, haemoglobin (Hb) catalyses nitrite reduction through a reaction modulated by haem redox potential and oxygen saturation, resulting in maximal NO production around the Hb P₅₀. Although ...

Pentacoordinate respiratory hemoproteins such as hemoglobin and myoglobin have evolved to supply cells with oxygen. However, these respiratory heme proteins are also known to function as redox enzymes, reacting with compounds such as nitric oxide and peroxides. The recent discoveries of hexacoordinate hemoglobins in vertebrates and nonsymbiotic plants suggest that ...

Oxidative/nitrosative stress plays an important role in the pathogenesis of hepatic encephalopathy and ammonia toxicity. The present study was undertaken in order to investigate the impact of portal vein ligation on cerebrocortical oxidative stress and its relation to locomotor activity. Cerebral protein tyrosine nitration, RNA oxidation, locomotor activity, and microglia ...

To correlate the effect of red blood cell hemoglobin on signal generation during magnetic resonance (MR) imaging and local oxidation of low-density lipoprotein (LDL). Informed consent was obtained from all volunteers participating in this study, which was approved by the research ethics board. T1 relaxometry of blood samples from six ...

A method to simultaneously measure oxygenation in vascular, intracellular, and mitochondrial spaces from optical spectra acquired from muscle has been developed. In order to validate the method, optical spectra in the visible and near-infrared regions (600-850 nm) were acquired from solutions of myoglobin, hemoglobin, and cytochrome oxidase that included Intralipid ...

The formation and interconversion of nitrogen oxides has been of interest in numerous contexts for decades. Early studies focused on gas-phase reactions, particularly with regard to industrial and atmospheric environments, and on nitrogen fixation. Additionally, investigation of the coordination chemistry of nitric oxide (NO) with hemoglobin dates back nearly a ...

Polynitroxylated hemoglobin (Hb(AcTPO)(12)) has been developed as a hemoglobin-based oxygen carrier. While Hb(AcTPO)(12) has been shown to exert beneficial effects in a number of models of oxidative injury, its peroxidase activity has not been characterized thus far. In the blood stream, Hb(AcTPO)(12) undergoes reduction by ascorbate to its hydroxylamine form ...

The design and general synthesis of enantiopure isoxazolidinone monomers as precursors for the preparation of enantiopure N-terminal hydroxylamine-β(3)-oligopeptides, which may be used as reaction partners with α-ketoacids in the decarboxylative amide ligation reaction, is described.

We investigated whether red cell infiltration of atheromatous lesions promotes the later stages of atherosclerosis. We find that oxidation of ferro (FeII) hemoglobin in ruptured advanced lesions occurs generating ferri (FeIII) hemoglobin and via more extensive oxidation ferrylhemoglobin (FeIII/FeIV=O). The protein oxidation marker dityrosine accumulates in complicated lesions, accompanied by ...

Nitric oxide (NO)-mediated angiogenesis may play a role in establishing dense retinal vasculatures of Antarctic hemoglobinless icefishes (suborder: Notothenioidei). We hypothesized that loss of hemoglobin (Hb) leads to elevation in [NO] due to decreased degradation of the compound when the NO-scavenger Hb is absent, thereby inducing vascular growth. We found ...

Isolating elemental steps that comprise a protein reaction in solution is a difficult process. In this study, the use of sugar-derived glass matrices is evaluated as a biophysical tool to help dissect out elemental steps and isolate intermediates. Two features of the glass are utilized in this endeavor: (i) the ...

The aim of this study was to evaluate the ability of the well-known radical scavenging compound edaravone (EDA) to entrap and detoxify reactive carbonyl species (RCS) derived from lipid peroxidation [4-hydroxy-trans-2-nonenal (HNE), acrolein and glyoxal], as well as its ability to prevent RCS-induced protein carbonylation, by using hemoglobin (Hb) modified ...

The malaria parasite, Plasmodium falciparum, develops within human erythrocytes, consuming host hemoglobin to support its own growth. Reactive oxygen species (superoxide and hydrogen peroxide) are by-products of hemoglobin digestion and are believed to exert significant oxidative stress on the parasite. We have characterized a cell permeant, far red fluorescent nucleic ...

Hemoglobin-based oxygen carriers (HBOC) are currently being developed as red blood cell (RBC) substitutes for use in transfusion medicine. Despite significant commercial development, late stage clinical results of polymerized hemoglobin (PolyHb) solutions hamper development. We synthesized two types of PolyHbs with ultrahigh molecular weights: tense (T) state PolyHb (M(W)=16.59 MDa ...

Hemoglobin is considered a potentially toxic molecule when released from erythrocytes during hemolysis, inflammation, or tissue injury. The mechanisms of toxicity involve reduced nitric oxide bioavailability and oxidative processes both occurring at the heme prosthetic groups. When the endogenous oxidant H(2)O(2) reacts with Hb, transient radicals are generated during the ...

Heme is an essential molecule in aerobic organisms. Heme consists of protoporphyrin IX and a ferrous (Fe(2+)) iron atom, which has high affinity for oxygen (O(2)). Hemoglobin, the major oxygen-carrying protein in blood, is the most abundant heme-protein in animals and humans. Hemoglobin consists of four globin subunits (alpha(2)beta(2)), with ...

For a vast majority of living organisms, haem is an essential compound that is synthesised through a conserved biosynthetic pathway. However, certain organisms are haem auxotrophs and need to obtain this molecule from exogenous sources. Kinetoplastid flagellates represent an interesting group of species, as some of them lost the complete ...

Mycobacterium tuberculosis group I truncated hemoglobin trHbN catalyzes the oxidation of nitric oxide (NO) to nitrate with a second-order rate constant k approximately 745 microM(-1) s(-1) at 23 degrees C (nitric oxide dioxygenase reaction). It was proposed that this high efficiency is associated with the presence of hydrophobic tunnels inside ...

Recent studies have demonstrated that hemoglobins isolated from Antarctic fish undergo peculiar oxidation processes. Here we show, by combining crystallographic and spectroscopic data, that the oxidation pathway of Trematomus bernacchii hemoglobin (HbTb) is distinct from that observed for the major component of Trematomus newnesi (Hb1Tn), despite the high sequence identity ...

Nitrite can react in parallel with adult oxy- and deoxy-hemoglobin (HbA), resulting in oxidative denitrosylation of nitrosyl-hemoglobin and rapid dissociation of nitric oxide. Here, simulation studies are presented using a new model to analyze data in the literature comparing the reaction of nitrite with isolated human oxy-HbA, oxy-fetal hemoglobin (oxy-HbF) ...

Cross-linked hemoglobin-azides react with a bis-alkyne to form a bis-tetramer through sequential "click" reactions where the second step is promoted by the first.

We have determined the second-order reverse rate constant, k(R), for the reaction of 5,5 -dithiobis(2-nitrobenzoate) - DTNB - with sheep hemoglobins as a function of pH from values of the second-order forward rate constant, k(F), and the equilibrium constant, K(equ), at 25 degrees C: k(R)=k(F)K(equ). We demonstrate that (i) inositol ...

The efficiency of different reductants (reduced glutathione, ascorbic acid, and catalase) and metal chelators [ethylenediaminetetraacetic acid (EDTA), citric acid, sodium tripolyphosphate (STPP), and adenosine-5'-triphosphate (ATP)] to inhibit lipid oxidation promoted by fish hemoglobin was investigated. The inhibitory activity on hemoglobin-catalyzed lipid oxidation was also evaluated for grape oligomeric catechins (proanthocyanidins), ...

Hemoglobin is a member of the hemoprotein superfamily whose main role is to transport O(2) in vertebrate organisms. It has two known promiscuous enzymatic activities, peroxidase and oxygenase. Here we show for the first time that bovine hemoglobin also presents a catalase-like activity characterized by a V(max )of 344 microM/min, ...

The protected transport of nitric oxide (NO) by hemoglobin (Hb) links the metabolic activity of working tissue to the regulation of its local blood supply through hypoxic vasodilation. This physiologic mechanism is allosterically coupled to the O(2) saturation of Hb and involves the covalent binding of NO to a cysteine ...

Hemoglobin (Hb) from rainbow trout (Oncorhynchus mykiss), Atlantic cod (Gadus morhua), and herring (Clupea harengus) were evaluated in terms of capacity to generate hydroperoxide-derived free radicals in aqueous solution at pH 6.8. Cumene hydroperoxide (CumOOH) was used as a model for preformed lipid hydroperoxides, and free radicals were monitored by ...

The capacity of Atlantic pollock ( Pollachius pollachius ), seabass ( Dicentrarchus labrax ), and horse mackerel ( Trachurus trachurus ) hemoglobin (Hb) to promote lipid oxidation has been evaluated in liposomes and washed minced horse mackerel muscle. The pro-oxidant ability of fish Hbs was related with their vulnerability to ...

Release of hemoglobin (Hb) into the circulation is a central pathophysiologic event that contributes to morbidity and mortality in chronic hemolytic anemias and severe malaria. These toxicities arise from Hb-mediated vasoactivity, possibly due to NO scavenging and localized tissue oxidative processes. Currently, there is no established treatment that targets circulating ...

3-Butene-1,2-diol (BDD), a known in vivo metabolite of 1,3-butadiene, is oxidized to a reactive Michael acceptor, hydroxymethylvinyl ketone (HMVK). Previously, we characterized the formation of three HMVK-amino acid monoadducts when HMVK was incubated in vitro with N-acetyl-l-cysteine, l-valinamide, and N-acetyl-l-lysine (NAL) at physiological conditions. One HMVK-NAL cyclic diadduct (cyclic diadduct ...

Cross-linked hemoglobins (Hbs) were found to have enhanced oxidative reactions which compromise the ability of cell-free Hb to carry oxygen. Zero-link bovine Hb (ZL-HbBv), also known as OxyVita, a large polymer held together by pseudopeptide bonds on the surface of adjacent tetramers, provides a model in which these reactions can ...

Uncontrolled oxidative reactions of hemoglobin (Hb) are still the main unresolved problem for Hb-based blood substitute developers. Spontaneous oxidation of acellular ferrous Hb into a nonfunctional ferric Hb generates superoxide anion. Hydrogen peroxide, formed after superoxide anion dismutation, may react with ferrous/ferric Hb to produce toxic ferryl Hb, fluorescent heme ...

The ferryl derivatives of hemoglobin are products of the reactions of oxy- and methemoglobin with hydrogen peroxide. Ferryl hemoglobins, either with or without a radical site on the protein moiety, are oxidizing species. Plant polyphenols, flavonoids, have been shown to act as antioxidants in vivo and in vitro. Reactions of ...

Although stabilized hemoglobins have been evaluated as oxygen-carrying replacements for red cells in transfusions, in vivo evaluations have noted that these materials are associated with vasoactivity, a serious complication. Scavenging of endogenous nitric oxide by the deoxyheme sites of the stabilized proteins is one likely source of vasoactivity. Recent reports ...

Effects of thiamine and its derivatives on inhibition of dityrosine formation were studied in reactions catalyzed by oxoferryl forms of hemoglobin. At high thiamine concentrations, a complete inhibition of dityrosine formation was observed due to interaction of tyrosyl radicals with thiamine tricyclic and thiol forms. In neutral and alkaline media, ...

Compounds that bind to sickle hemoglobin (Hb S) producing an allosteric shift to the high-affinity Hb S that does not polymerize are being developed to treat sickle cell anemia (SCA). In this study, three series of pyridyl derivatives of substituted benzaldehydes (Classes I-III) that combine structural features of two previously ...

The synthesis of Li[(11)BD(4)] from LiB and D(2) (p = 180 bar) is investigated by in situ neutron diffraction. The onset of the Li[(11)BD(4)] formation is observed far below the temperatures reported so far for the reaction from the pure elements, indicative of a lower activation barrier. We attribute the ...

Cell-free hemoglobin (Hb) enhances the oxidation-related toxicity associated with inflammation, ischemia, and hemolytic disorders. Hb is highly vulnerable to oxidative damage, and irreversible structural changes involving iron/heme oxidation, heme-adduct products, and amino acid oxidation have been reported. Specific structural features of Hb, such as unconstrained alpha-chains and molecular size, determine ...

The Pictet-Spengler reaction was applied to the N-terminal labeling of horse heart myoglobin. This was performed in the following two steps: (1) conversion of the N-terminal glycine residue to an alpha-keto aldehyde by a transamination reaction and (2) condensation of the resulting activated myoglobin with tryptamine analogues by the Pictet-Spengler ...

Intracellular porphyrin generation following administration of 5-aminolaevulinic acid (ALA) has been widely used in photodynamic therapy for a range of malignant and nonmalignant lesions. However, ALA is relatively hydrophilic and lacks stability at physiologic pH, limiting its bioavailability. We have investigated more lipophilic, uncharged ALA-peptide prodrugs based on phenylalanyl-ALA conjugates, ...

The toxicity of acellular hemoglobin (Hb)-based therapeutics has been attributed in part to the uncontrolled oxidative reactions. A variety of antioxidant strategies to ameliorate potential oxidative damage in vivo have been suggested. We have examined the effects of (-)-epigallocatechin gallate (EGCG), a green tea polyphenol compound widely regarded as a ...

The nitrite reductase activity of deoxyhemoglobin has received much recent interest because the nitric oxide produced in this reaction may participate in blood flow regulation during hypoxia. The present study used spectral deconvolution to characterize the reaction of nitrite with carp and rabbit hemoglobin at different constant oxygen tensions that ...

The reaction of deoxyhemoglobin with nitrite was characterized in the presence of dithionite using hemoglobin in solution or bound to the cytoplasmic domain of band 3 (CDB3). Deoxyhemoglobin was generated by predeoxygenation (nitrogen flushing followed by addition of dithionite), or transiently, by rapidly mixing oxyhemoglobin with nitrite and dithionite simultaneously. ...

The trans-to-cis photoisomerization of the p-coumaroyl chromophore of photoactive yellow protein (PYP) triggers the photocycle. Met100, which is located in the vicinity of the chromophore, is a key residue for the cis-to-trans back-isomerization of the chromophore, which is a rate-determining reaction of the PYP photocycle. Here we characterized the photocycle ...