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PubMed2002

Who's that talking?

The case of a man aged 37, with symptoms suggesting paranoid schizophrenia is discussed. There was a rapid and sustained response to Kalium bromatum.

Adult↗
PubMed1973

Identification of 50S proteins at the peptidyl-tRNA binding site of Escherichia coli ribosomes.

Bromoacetyl-phenylalanyl-tRNA(phe) bound to 70S E. coli ribosomes reacts covalently with proteins of the 50S subunit. The major reactions are with proteins L2 and L27. In the presence of poly(U), 70S-bound bromoacetyl-phenylalanyl-tRNA(phe) can participate in peptidebond formation with phenylalanyl-tRNA(phe) or puromycin. Most of the products of these reactions are also found covalently attached to L2 and L27. Chloramphenicol and sparsomycin markedly inhibit the peptide-bond formation. These results strongly suggest that bromoacetylphenylalanyl-tRNA(phe) can function as a normal peptidyl-tRNA and that the 50S proteins, L2 and L27, are located in the peptidyl-tRNA binding site. The side reactions of bromoacetyl-phenylalanyl-tRNA(phe) are with one or more 50S proteins from the set L14-17, L6 and/or L11, and L26. These occur to a much less extent than the reactions with L2 and L27. Any functional significance of the side reactions is unknown.

Acetates↗
PubMed2004

Endogenous formation of novel halogenated 2'-deoxycytidine. Hypohalous acid-mediated DNA modification at the site of inflammation.

A potential role of DNA damage by leukocyte-derived reactive species in carcinogenesis has been suggested. Leukocyte-derived peroxidases, such as myeloperoxidase and eosinophil peroxidase, use hydrogen peroxide and halides (Cl- and Br-) to generate hypohalous acids (HOCl and HOBr), halogenating intermediates. It has been suggested that these oxidants lead to the formation of halogenated products upon reaction with nucleobases. To verify the consequences of phagocyte-mediated DNA damage at the site of inflammation, we developed a novel monoclonal antibody (mAb2D3) that recognizes the hypohalous acid-modified DNA and found that the antibody most significantly recognized HOCl/HOBr-modified 2'-deoxycytidine residues. The immunoreactivity of HOCl-treated oligonucleotide was attenuated by excess methionine, suggesting that chloramine-like species may be the plausible epitopes of the antibody. On the basis of further characterization combined with mass spectrometric analysis, the epitopes of mAb2D3 were determined to be novel N4,5-dihalogenated 2'-deoxycytidine residues. The formation of the dihalogenated 2'-deoxycytidine in vivo was immunohistochemically demonstrated in the lung and liver nuclei of mice treated with lipopolysaccharides, an experimental inflammatory model. These results strongly suggest that phagocyte-derived oxidants, hypohalous acids, endogenously generate the halogenated DNA bases such as a novel dihalogenated 2'-deoxycytidine in vivo. Halogenation (chlorination and/or bromination) of DNA therefore may constitute one mechanism for oxidative DNA damage at the site of inflammation.

Animals↗
PubMed2004

Role of thiocyanate, bromide and hypobromous acid in hydrogen peroxide-induced apoptosis.

We have previously reported that H2O2-induced apoptosis in HL-60 human leukemia cells takes place in the presence of chloride, requires myeloperoxidase (MPO), and occurs through oxidative reactions involving hypochlorous acid and chloramines. We now report that when chloride is replaced by the pseudohalide thiocyanate, there is little or no H2O2-induced apoptosis. Furthermore, thiocyanate inhibits H2O2-induced apoptosis when chloride is present at physiological concentrations, and this occurs at thiocyanate concentrations that are present in human serum and saliva. In contrast, bromide can substitute for chloride in H2O2-induced apoptosis, but results in a lower percent of the cells induced into apoptosis. Hypobromous acid is likely a short-lived intermediate in this H2O2/MPO/bromide apoptosis, and reagent hypobromous acid and bromamines induce apoptosis in HL-60 cells. We conclude that the physiologic concentrations of thiocyanate found in human plasma could modulate the cytototoxicity of H2O2 and its resulting highly toxic MPO-generated hypochlorous acid by competing with chloride for MPO. Furthermore, the oxidative products of the reaction of thiocyanate with MPO are relatively innocuous for human leukemic cells in culture. In contrast, bromide can support H2O2/MPO/halide apoptosis, but is less potent than chloride and it has no effect in the presence of physiological levels of chloride.

Amines↗
PubMed2001

Pattern formation in a tunable medium: the Belousov-Zhabotinsky reaction in an aerosol OT microemulsion.

Turing structures, standing waves, oscillatory clusters, and accelerating waves have been found in the spatially extended Belousov-Zhabotinsky system dispersed in water droplets of a reverse AOT microemulsion. The variety of patterns is determined by the tunable microstructure of the medium, i.e., by the concentration and size of water droplets. We propose a simple model to describe this system.

Aerosols↗
PubMed1990

Structure of nickel(II) perbromate hexahydrate at 296 K.

Ni(BrO4)2.6H2O, Mr = 454.61, trigonal, P3, a = 7.874 (1), c = 5.423 (2) A, V = 291.2 (1) A3, Z = 1, D chi = 2.59 g cm-3, lambda(Mo K alpha) = 0.71069 A, mu = 85.36 cm-1, F(000) = 222, T = 296 K, R = 0.029 for 457 unique reflections having I greater than 0. The room-temperature structure is very similar to that reported previously for a sample at 169 K. The water O atoms form a very slightly distorted octahedron about nickel while the perbromate-ion geometry is virtually regular tetrahedral. Both the coordination polyhedron and the perbromate ion were tested and found to behave as rigid bodies. Corrected for rigid-body motion, the Ni--O(2) distance is 2.064 (2) A and the mean Br--O distance in the perbromate ion is 1.629 (3) A. A detailed account of the hydrogen bonding is presented. The structure previously determined at 169 K is most probably not the stable structure at that temperature.

Bromates↗
PubMed1992

Structure of sodium perbromate monohydrate.

NaBrO4.H2O, Mr = 184.90, monoclinic, C2/c, a = 15.7575 (19), b = 5.7373 (15), c = 11.3390 (19) A, beta = 111.193 (10)degrees, V = 955.8 (3) A3, Z = 8, Dx = 2.570 g cm-3, lambda(Mo K alpha) = 0.71073 A, mu = 85.2 cm-1, F(000) = 704, T = 296 K, R = 0.039 for 1137 unique reflections having I greater than sigma I. In this structure, there are two inequivalent Na ions, each coordinated by six O atoms. In each of the two types of distorted octahedra, there are three inequivalent Na--O distances; the average Na(1)--O and Na(2)--O distances are 2.379 (10) and 2.405 (23) A, respectively. The perbromate ion in this structure displays very nearly regular tetrahedral geometry, although it is subject to no symmetry constraints; the average observed Br--O distance is 1.601 (4) A, while the average observed O--Br--O angle is 109.5 (9)degrees. These values agree well with previously reported values. The perbromate ion, but neither of the sodium coordination polyhedra, shows rigid-body behavior. The average rigid-body corrected Br--O distance in the perbromate ion is 1.624 (3) A. Refinement of the two inequivalent H atoms permitted detailed analysis of the hydrogen bonding, which is slightly different from that reported for the isomorphic sodium perchlorate monohydrate. Dynamic disordering of the H atoms as detailed by magnetic resonance methods for sodium perchlorate monohydrate is not clearly indicated in our X-ray study of sodium perbromate monohydrate.

Bromates↗
PubMed1993

Structure of tetraaquacalcium perbromate.

The structure of the title compound consists of columns of Ca ions surrounded by four columns of perbromate ions and four columns of water molecules alternating in pairs. The CaO8 complex was found to be dimensionally similar to corresponding complexes in other simple tetrahydrated calcium salts. The eight coordinating O atoms form a polyhedron which departs only slightly from a (distorted) square antiprism. Each of the crystallographically inequivalent perbromate ions was found to conform to rigid-body behavior while the CaO8 complex did not. Although the perbromate ions depart moderately from regular tetrahedral geometry, the mean Br--O bond length agrees well with previously determined values. Hydrogen bonds in this structure involve water-oxygen acceptors as well as perbromate-oxygen acceptors.

Bromates↗
PubMed1995

Lithium perbromate monohydrate at 296 and 173 K.

Lithium tetraoxobromate(1-) monohydrate, LiBrO4.-H2O, whose perchlorate analog has not yet been described, is found to be isomorphic with NaBrO4.H2O and NaClO4.H2O. Each of the two inequivalent Li ions is coordinated by six O atoms, thus forming distorted octahedra, each of which has three inequivalent Li-O distances. At room temperature, the average Li(1)-O and Li(2)-O distances are 2.150 and 2.164 A, respectively. The perbromate ion displays very nearly regular tetrahedral geometry, although it is not subject to symmetry constraints. At 296 K the average observed Br-O distance is 1.610 (4) A and the average O-Br-O angle is 109.5 (6) degrees, while at 173 K the corresponding values are 1.613 (4) A and 109.5 (7) degrees. The perbromate ion shows rigid-body behavior but the lithium coordination polyhedra do not. At 296 K, the average rigid-body corrected Br-O distance in the perbromate ion is 1.624 (3) A, in excellent agreement with the corresponding value reported for NaBrO4.H2O. Refinement of the two inequivalent H atoms allowed detailed analysis of the hydrogen bonding, which is more extensive than in NaBrO4.H2O or in NaClO4.H2O. The average observed B values for the H atoms [2.9 (3) A2 at 296 K and 2.8 (3) A2 at 173 K] are sufficiently small to suggest that dynamic disordering of the H atoms (determined by magnetic resonance methods for NaClO4.H2O) is not significant in the title salt.

Bromates↗
PubMed1986

Brominating oxidants generated by human eosinophils.

Eosinophils are white blood cells that in humans are found in association with helminthic infections and various inflammatory disease processes. These cells contain a unique lysosomal peroxidase that oxidizes halides to generate highly reactive and toxic hypohalous acids. Although chloride is found in vivo at concentrations at least 1000-fold greater than those of other halides, human eosinophils did not preferentially oxidize chloride under physiologic conditions. Instead, eosinophils used bromide, a halide with a hitherto unknown function in humans, to generate a halogenating oxidant with characteristics similar, if not identical, to those of hypobromous acid. These results indicate that physiological concentrations of bromide arm human eosinophils with the ability to generate and release an unusual oxidant capable of destroying a wide range of prokaryotic and eukaryotic targets.

Bromates↗
PubMed2001

Reaction of acylated homoserine lactone bacterial signaling molecules with oxidized halogen antimicrobials.

Oxidized halogen antimicrobials, such as hypochlorous and hypobromous acids, have been used extensively for microbial control in industrial systems. Recent discoveries have shown that acylated homoserine lactone cell-to-cell signaling molecules are important for biofilm formation in Pseudomonas aeruginosa, suggesting that biofouling can be controlled by interfering with bacterial cell-to-cell communication. This study was conducted to investigate the potential for oxidized halogens to react with acylated homoserine lactone-based signaling molecules. Acylated homoserine lactones containing a 3-oxo group were found to rapidly react with oxidized halogens, while acylated homoserine lactones lacking the 3-oxo functionality did not react. The Chromobacterium violaceum CV026 bioassay was used to determine the effects of such reactions on acylated homoserine lactone activity. The results demonstrated that 3-oxo acyl homoserine lactone activity was rapidly lost upon exposure to oxidized halogens; however, acylated homoserine lactones lacking the 3-oxo group retained activity. Experiments with the marine alga Laminaria digitata demonstrated that natural haloperoxidase systems are capable of mediating the deactivation of acylated homoserine lactones. This may illustrate a natural defense mechanism to prevent biofouling on the surface of this marine alga. The Chromobacterium violaceum activity assay illustrates that reactions between 3-oxo acylated homoserine lactone molecules and oxidized halogens do occur despite the presence of biofilm components at much greater concentrations. This work suggests that oxidized halogens may control biofilm not only via a cidal mechanism, but also by possibly interfering with 3-oxo acylated homoserine lactone-based cell signaling.

4-Butyrolactone↗
PubMed1983

Nitrate uptake in Aspergillus nidulans and involvement of the third gene of the nitrate assimilation gene cluster.

In Aspergillus nidulans, chlorate strongly inhibited net nitrate uptake, a process separate and distinct from, but dependent upon, the nitrate reductase reaction. Uptake was inhibited by uncouplers, indicating that a proton gradient across the plasma membrane is required. Cyanide, azide, and N-ethylmaleimide were also potent inhibitors of uptake, but these compounds also inhibited nitrate reductase. The net uptake kinetics were problematic, presumably due to the presence of more than one uptake system and the dependence on nitrate reduction, but an apparent Km of 200 microM was estimated. In uptake assays, the crnA1 mutation reduced nitrate uptake severalfold in conidiospores and young mycelia but had no effect in older mycelia. Several growth tests also indicate that crnA1 reduces nitrate uptake. crnA expression was subject to control by the positive-acting regulatory gene areA, mediating nitrogen metabolite repression, but was not under the control of the positive-acting regulatory gene nirA, mediating nitrate induction.

Aspergillus nidulans↗
PubMed2006

Indirect kinetic spectrophotometric determination of hydroxylamine based on its reaction with iodate.

A simple, precise and accurate method is proposed for rapid determination of trace amounts of hydroxylamine based on the reaction of hydroxylamine with iodate in acidic media. The reaction of neutral red by the produced nitrite ion was used to monitor the reaction spectrophotometrically at 525 nm by a fixed time method. Hydroxylamine in the range of 0.0400-1.200 microg mL(-1) could be determined. The relative standard deviation for 10 determinations of 0.500 microg mL(-1) hydroxylamine was 1.81% and the limit of detection was 0.010 microg mL(-1). The proposed method was applied to the determination of hydroxylamine in water samples with satisfactory results.

Alcohols↗
PubMed2006

Kinetics of the reaction of hypobromous acid and organic matters in water treatment processes.

The fate of bromine species from human activity is affected by the bromination reaction in water treatment processes. In this study, kinetic information of the reaction between hypobromous acid (HOBr) and seven different natural organic matters (NOM) was collected by sequential stopped-flow techniques. Multiple reaction phases were found in the reaction between HOBr and NOM. The number of reaction sites for the faster reaction phase ranged from 0.26 to 0.92 micromole (mg DOC)(-1), and was correlated to both SUVA and specific phenolic content at pH 7.0. The apparent second-order rate constants for the faster reaction phase at pH 7.0 ranged from 5.4 x 10(5) to 1.4 x 10(6) M(-1) x s(-1), indicating that vanillin-like structures are involved in this reaction phase.

Benzaldehydes↗