Showing papers on "Cyanide published in 1999"
TL;DR: The Fe(I) organometallic complex provides a structural model for the cyano-carbonyl diiron site of Fe-only hydrogenase as characterized by X-ray crystallography.
Abstract: The Fe(I) organometallic complex [(µ-SCH(2)CH(2)CH(2)S)Fe(2)(CO)(6)] provides a structural model for the cyano-carbonyl diiron site of Fe-only hydrogenase as characterized by X-ray crystallography (the picture shows the structure (black) of the model overlaid with that of the Fe-Fe dimetallic site in the hydrogenase isolated from Desulfovibrio desulfuricans). Cyanide substitution of CO occurs readily and provides spectroscopic references for the active site.
353 citations
TL;DR: Infrared-spectroscopic studies on the [NiFe]-hydrogenase of Chromatium vinosum-enriched in15N or 13C, as well as chemical analyses, show that this enzyme contains three non-exchangeable, intrinsic, diatomic molecules as ligands to the active site, one carbon monoxide molecule and two cyanide groups.
239 citations
TL;DR: The x-ray structures demonstrate the flexibility and dynamic character of the aromatic donor binding site in horseradish peroxidase and emphasize the role of the distal arginine (Arg38) in both substrate oxidation and ligand binding.
206 citations
186 citations
TL;DR: The most important cyanide compounds, as well as the most important sources of cyanide contamination in soils and groundwater are discussed in this paper, where the risk associated to the cyanide contained in the different types of sources is evaluated.
Abstract: Most people associate the word cyanide with an extremely dangerous and fast-acting poison. However, there are several cyanide species, of varying toxicity, depending on the source to cyanide contamination. The most important cyanide compounds, as well as the most important sources of cyanide contamination in soils and groundwater are discussed. Toxicological and analytical aspects of cyanide containing compounds are briefly touched. The behaviour of cyanide compounds in soil and groundwater is governed by many interacting chemical and microbial processes. Redox conditions and pH are of importance for the leaching and degradation of iron cyanide complexes. Free cyanide is degraded under both aerobic and anaerobic conditions, while documentation of the degradability of iron cyanide complexes only exists under aerobic conditions. The risk associated to the cyanide contained in the different types of sources is evaluated. At gas work sites, where cyanide is mainly present as iron cyanide complexes, the risk for effects on humans from exposure to cyanide compounds seems to be of minor relevance.
147 citations
TL;DR: The results of this in situ study show that an impairment of zooxanthellar photosynthesis is the site of cyanide-mediated toxicity, and is the cue that causes corals to release their symbiotic zoxanthellac following cyanide exposure.
147 citations
TL;DR: The toxicity and fate of cyanide breakdown products, either during treatment or during natural degradation, is poorly understood as discussed by the authors, and further studies need to be conducted in order to adequately evaluate the environmental fate and associated toxicity to higher plants and animals.
Abstract: Disclaimer. Although the research described in this manuscript has been funded wholly or in part by the EPA, Contract #68D10135, it has not been subjected to the Agency's review and therefore does not necessarily reflect the views of the Agency; no official endorsement should be inferred. Cyanides are ‘priority pollutants’ under the Clean Water Act. A number of Superfund sites, particularly mining and minerals processing sites, have released cyanide wastes to the environment. Free cyanide is present in water from the dissolution of compounds such as sodium cyanate, potassium cyanide, and hydrogen cyanide. The toxicity and fate of cyanide breakdown products, either during treatment or during natural degradation, is poorly understood. Aqueous species of particular concern are cyanate (CNO-), thiocyanate (SCN-), and cyanogen chloride (CNCl-). The toxicity of these compounds to aquatic life is highly variable depending on environmental conditions, including physicochemical and microbial influences. Information pertaining to aquatic plant uptake of these cyanide ligands could not be located in the literature, while only a few studies addressing terrestrial plant uptake of cyanide (and only in the form of NaCN) could be found. In order to adequately evaluate the environmental fate and associated toxicity to higher plants and animals, further studies need to be conducted.
130 citations
TL;DR: Primary and secondary alkyl halides and sulfonates undergo rapid and efficient azide or cyanide displacement in the absence of phase transfer catalysts with the silicate derivatives, and application of these reagents to the stereoselective synthesis of glycosyl azide derivatives is reported.
Abstract: Hypervalent azido- and cyanosilicate derivatives, prepared in situ by the reaction of trimethylsilyl azide or trimethylsilyl cyanide, respectively, with tetrabutylammonium fluoride, are effective sources of nucleophilic azide or cyanide. Primary and secondary alkyl halides and sulfonates undergo rapid and efficient azide or cyanide displacement in the absence of phase transfer catalysts with the silicate derivatives. Application of these reagents to the stereoselective synthesis of glycosyl azide derivatives is reported.
123 citations
TL;DR: In cyanide poisoning, metalloproteins and carbonyl groups containing proteins are the main target molecules of nucleophilic attack by cyanide and catalyzed by rhodanese and mercaptopyruvate sulfurtransferase (MST), which was an evolutionarily related enzyme of r Rhodanese.
Abstract: In cyanide poisoning, metalloproteins and carbonyl groups containing proteins are the main target molecules of nucleophilic attack by cyanide. To defend against this attack, cyanide is metabolized to less toxic thiocyanate via transsulfuration. This reaction is catalyzed by rhodanese and mercaptopyruvate sulfurtransferase (MST). Rhodanese is a well characterized mitochondrial enzyme. On the other hand, little was known about MST because it was unstable and difficult to purify. We first purified MST to homogeneity and cloned MST cDNA from rat liver to characterize MST. We also found that MST was an evolutionarily related enzyme of rhodanese. MST and rhodanese are widely distributed in rat tissues, and the kidney and liver prominently contain these enzymes. Immunohistochemical study revealed that MST is mainly distributed in proximal tubular epithelial cells in the kidney, pericentral hepatocytes in the liver, the perinuclear area of myocardial cells in the heart, and glial cells in the brain, and immunoelectron microscopical study concluded that MST was distributed in both cytoplasm and mitochondria, so that MST first detoxifies cyanide in cytoplasm and the cyanide which escapes from catalysis due to MST enters mitochondria. MST then detoxifies cyanide again in cooperation with rhodanese in mitochondria. Tissues other than the liver and kidney are more susceptible to cyanide toxicity because they contain less MST and rhodanese. Even in the same tissue, sensitivity to cyanide toxicity may differ according to the kind of cell. It is determined by a balance between the amount of proteins to be attacked and that of enzymes to defend.
121 citations
TL;DR: Cyanide causes the dissociation of the symbiosis (bleaching) by affecting photosynthesis of the zooxanthellae, consistent with the known property of cyanide as an inhibitor of the dark reactions of the Calvin cycle.
Abstract: Modulated chlorophyll fluorescence techniques were used to examine the effects of cyanide (NaCN) from cyanide fishing on photosynthesis of the symbiotic algae (zooxanthellae) located within the tissues of the zooxanthellate hard coral Plesiastrea versipora. Incubating corals for 3 h in a cyanide concentration of >10(-5) M NaCN under a saturating light intensity (photosynthetically active radiation [PAR] intensity of 250 mu mol quanta m(-2) s(-1)) caused a long-term decrease in the ratio of variable to maximal fluorescence (dark-adapted F-v/F-m). The effect of cyanide on dark-adapted F-v/F-m was Light dependent; thus F-v/F-m only decreased in corals exposed to 10(-4) M NaCN for 3 h under PAR of 250 mu mol quanta m(-2) s(-1). In corals where dark-adapted F-v/F-m was significantly lowered by cyanide exposure, we observed significant loss of zooxanthellae from the tissues. causing the corals to discolour (bleach). To further examine the light-dependent effect of cyanide and its relation to loss of zooxanthellae, corals were exposed to 10-4 M NaCN or seawater only (control), either in darkness or under 250 mu mol quanta m(-2) s(-1). ill significant decrease in dark-adapted F-v/F-m and loss of zooxanthellae only occurred in corals exposed to cyanide in the light. These results suggest cyanide causes the dissociation of the symbiosis (bleaching) by affecting photosynthesis of the zooxanthellae. Quenching analysis using the saturation-pulse technique revealed the development of high levels of non-photochemical quenching in cyanide-exposed coral. This result is consistent with the known property of cyanide as an inhibitor of the dark reactions of the Calvin cycle, specifically as an inhibitor of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). Therefore, chronic photoinhibition and an impairment of photosynthesis of zooxanthellae provides an important 'signal' to examine the environmental effects of cyanide fishing during controlled releases in situ.
106 citations
TL;DR: A series of novel composite inorganic-organic materials from the copper-cyanide-triazolate-organoamine system have been isolated and structurally characterized and discussed in relation to the supramolecular chemistry of other copper cyanide solid-state materials.
Abstract: A series of novel composite inorganic−organic materials from the copper−cyanide−triazolate−organoamine system have been isolated and structurally characterized. An unusual interpenetrating layered ...
TL;DR: In this article, the binding capacity of the biosorbent was investigated as a function of the initial pH, initial iron(III)-cyanide complex ion and biosorbents concentration.
TL;DR: Chronic cyanide exposure may be deleterious to liver and kidney functions, as well as some associated enzyme and metabolite changes, when investigated in New Zealand white rabbits.
TL;DR: Investigating the fate of potassium cyanide administered orally to rats maintained for up to 4 weeks on either a balanced diet (BD) or a diet lacking the SAAs, L-cystine and L-methionine found a strongly positive linear relationship between blood CN- and plasma OCN- concentrations.
TL;DR: In this article, the theory and analytical applications of thin lipid films are reported, and several examples of the application of various methods for study of physical properties of supported bilayer lipid membranes are described.
Abstract: This article reports the theory and analytical applications of thin lipid films. Recent advances of electrochemical devices based on lipid membranes have lead to reports of construction of biosensors for environmental and food applications, and may provide opportunities for commercial fabrication. The methods of formation of lipid membranes on various supports including metals (silver, gold, stainless steel), agar, conducting polymers and ultrafiltration membranes have provided stabilization of lipid films with a diversity of analytical applications in real samples. Methods of immobilization and incorporation of various functional macromolecules are summarized. Several examples of the application of various methods for study of physical properties of supported bilayer lipid membranes are described. Applications of lipid-based biosensors in analytical chemistry for determination of compounds are demonstrated, including a diversity of chemical compounds such as environmental pollutants (ammonia and carbon dioxide, cyanide ions, etc.) and food toxins (aflatoxin M1and direct detection of toxin in real samples such as milk and milk preparations). Methods for application of liposomes as a sensing system are also summarized.
TL;DR: The unusual cyanide distal site orientation observed in L. pectinata HbI, at room temperature, may reflect reduction of the heme Fe(III) atom induced by free radical species during x-ray data collection using Cu Kalpha radiation.
TL;DR: In this paper, the degradation of free cells of P. fluorescens in the presence of glucose and dissolved oxygen was investigated as a function of initial pH, initial ferrocyanide and glucose concentrations and aeration rate in a batch fermenter.
TL;DR: In this paper, the authors investigated the feasibility of using a bipolar trickle tower electrochemical reactor consisting of graphite Raschig rings as the electrodes to remove cyanide from a cyanide containing effluent.
TL;DR: In this paper, the authors used the vibrational technique of Raman spectroscopy to determine the effect of highly saline water on the equilibrium distribution of copper cyanide complexes in solution for various CN/Cu molar ratios.
TL;DR: In this article, a summary of available information on iron cyanide use in road salt and its potential effects on water quality is presented, as well as estimates of total cyanide concentrations in snow-melt runoff from roadways.
Abstract: Water-soluble iron cyanide compounds are widely used as anticaking agents in road salt, creating potential contamination of surface and groundwater with these compounds when the salt dissolves and is washed off roads in runoff. This paper presents a summary of available information on iron cyanide use in road salt and its potential effects on water quality. Estimates of total cyanide concentrations in snow-melt runoff from roadways are also presented as simple mass-balance calculations.
TL;DR: In this paper, the influence of the presence of an organic compound (phenol) or of a strong oxidant (H2O2) on the photoprocess was also studied.
TL;DR: Cladosporium cladosporioides biomass was a highly efficient biosorbent of copper cyanide and nickel cyanide from aqueous solutions and was fit for discharge in the environment.
Abstract: Cladosporium cladosporioides biomass was a highly efficient biosorbent of copper cyanide and nickel cyanide from aqueous solutions. A 32–38 fold concentration of initial 0.5 mM metal cyanides could be achieved when biosorption process was carried out under standardised conditions. Residual, unrecoverable metal cyanide could be completely biodegraded in 5–6 h. The solution treated with the combined biosorption-biodegradation process was fit for discharge in the environment.
TL;DR: The palladium-catalyzed cyanation of aryl and heteroaryl iodides or bromides using copper(I) cyanide as a cyano group source afforded the corresponding aryal and heterOaryl cyanides in good yields.
Abstract: The palladium-catalyzed cyanation of aryl and heteroaryl iodides or bromides using copper(I) cyanide as a cyano group source afforded the corresponding aryl and heteroaryl cyanides in good yields.
TL;DR: In this paper, the role of the cyanide complexes of copper, silver, nickel, iron and zinc in gold leaching was investigated by examining the leaching of a copper concentrate, and it was found that copper-cyanide and other metal cyanide species, including Ag, Fe, Ni and Zn, all play an important role in gold cyanidation under conditions of zero free cyanide.
TL;DR: The characteristics of strain C-3 suggest that it would be useful in the bioremediation of cyanide-containing waste and could tolerate and grow in potassium cyanide at concentrations of up to 25 mM.
Abstract: A bacterium that utilizes cyanide as a nitrogen source was isolated from soil after enrichment in a liquid medium containing potassium cyanide (10 mM) and glucose (1.0%, w/v). The strain could tolerate and grow in potassium cyanide at concentrations of up to 25 mM. It could also utilize potassium cyanate, potassium thiocyanate, linamarin and a range of aliphatic and aromatic nitriles. The isolate was tentatively identified as Burkholderia cepacia strain C-3. Ammonia and formic acid were found in the culture supernatant of the strain grown on fructose and potassium cyanide, no formamide was detected, suggesting a hydrolytic pathway for the degradation of cyanide. The cyanide-degrading activity was higher in early and the stationary phase cells. Crude cell extracts of strain C-3 grown on nutrient broth exhibited cyanide-degrading activity. The characteristics of strain C-3 suggest that it would be useful in the bioremediation of cyanide-containing waste.
TL;DR: These newly synthesized compounds provide a new rationale for anti‐CN drugs, with fewer side‐effects than the methemoglobin formers, and alter the chemical substituent of the longer chain sulfide modified the ability of the candidate SSD to protect against CN toxicity.
Abstract: Antidotes for cyanide (CN) intoxication include the use of sulfane sulfur donors (SSDs), such as thiosulfate, which increase the conversion of CN to thiocyanate by the enzyme rhodanese. To develop pretreatments that might be useful against CN, SSDs with greater lipophilicity than thiosulfate were synthesized and assessed. The ability of SSDs to protect mice against 2LD50 of sodium cyanide (NaCN) administered either 15 or 60 min following administration of an SSD was assessed. To study the mechanism of action of the SSD, the candidate compounds were examined in vitro for their effect on rhodanese and 3-mercaptopyruvate sulfurtransferase (MST) activity under increasing SSD concentrations. Tests were conducted on nine candidate SSDs: ICD1021 (3-hydroxypyridin-2-yl N-[(N-methyl-3-aminopropyl)]-2-aminoethyl disulfide dihydrochloride), ICD1022, (3-hydroxypyridin-2-yl N-[(N-methyl-3-aminopropyl)]-2-aminoethyl disulfide trihydrochloride), ICD1584 (diethyl tetrasulfide), ICD1585 (diallyl tetrasulfide), ICD1587 (diisopropyl tetrasulfide); ICD1738 (N-(3-aminopropyl)-2-aminoethyl 2-oxopropyl disulfide dihydrochloride), ICD1816 (3,3'-tetrathiobis-N-acctyl-L-alanine), ICD2214 (2-aminoethyl 4-methoxyphenyl disulfide hydrochloride) and ICD2467 (bis(4-methoxyphenyl) disulfide). These tests demonstrated that altering the chemical substituent of the longer chain sulfide modified the ability of the candidate SSD to protect against CN toxicity. At least two of the SSDs at selected doses provided 100% protection against 2LD50 of NaCN, normally an LD99. All compounds were evaluated using locomotor activity as a measure of potential adverse behavioral effects. Positive hypoactivity relationships were found with several disulfides but none was found with ICD1584, a tetrasulfide. Separate studies suggest that the chemical reaction of potassium cyanide (KCN) and cystine forms the toxic metabolite 2-iminothiazolidine-4-carboxylic acid. An alternative detoxification pathway, one not primarily involving the sulfur transferases. may be important in pretreatment for CN intoxication. Although studies to elucidate the precise mechanisms are needed. it is clear that these newly synthesized compounds provide a new rationale for anti-CN drugs, with fewer side-effects than the methemoglobin formers.
TL;DR: In this paper, the equilibrium solubility behavior of iron cyanide solids was studied as a function of pH, pE, and other solution conditions, including those conducive to coprecipitation of IR solids and hydrous ferric oxide.
Abstract: Iron cyanide solids are complex coordination compounds that are produced and used in various commercial products and processes as well as clinical products. These solids are also present in spent potlining wastes associated with aluminum production sites and in areas of former manufactured gas plant (MGP) facilities as a result of disposal of cyanide-bearing materials in soils containing iron. In such cases, the concentration of cyanide in groundwater is governed by dissolution of the iron cyanide solids under various environmental conditions. Understanding of the precipitation and dissolution chemistry of iron cyanide solids is still in a nascent state, however. In this work, the equilibrium solubility behavior of iron cyanide solids was studied as a function of pH, pE, and other solution conditions, including those conducive to coprecipitation of iron cyanide solids and hydrous ferric oxide. Equilibrium solubility products were determined for reagent-grade Prussian Blue, and for synthesized Pru...
TL;DR: The present results confirmed that waste microbial biomaterials have some potential for removing and concentrating gold from solutions where it occurs as a gold-cyanide complex.
Abstract: Gold adsorption from cyanide solution by bacterial (Bacillus subtilis), fungal (Penicillium chrysogenum) and seaweed (Sargassum fluitans) biomass was examined. At pH 2.0, these biomass types were capable of sequestering up to 8.0 µmol g−1, 7.2 µmol g−1 and 3.2 µmol g−1, respectively. An adverse effect of increasing solution ionic strength (NaNO3) on gold biosorption was observed. Gold-loaded biomass could be eluted with 0.1 mol dm−3 NaOH with efficiencies higher than 90% at pH 5.0 at the Solid-to-Liquid ratio, S/L, = 4 (g dm−3). Cyanide mass balances for the adsorption, desorption as well as for the AVR process indicated the stability of the gold-cyanide which did not dissociate either upon acidification or upon binding by biomass functional groups. Gold biosorption mainly involved anionic AuCN2− species bound by ionizable biomass functional groups carrying a positive charge when protonated. FTIR analyses indicated that the main biomass functional groups involved in gold biosorption are most probably nitrogen-containing weak base groups. The present results confirmed that waste microbial biomaterials have some potential for removing and concentrating gold from solutions where it occurs as a gold-cyanide complex.
© 1999 Society of Chemical Industry
TL;DR: In this article, the authors studied the formation, fate, and transport of cyanide in a sand-gravel aquifer underlying an MGP site in the upper Midwest region of the United States.
Abstract: Cyanide is present at manufactured-gas plant (MGP) sites in oxide-box residuals, which were often managed on-site as fill during active operations. Cyanide can leach from these materials, causing groundwater contamination. Speciation, fate, and transport of cyanide in a sand-gravel aquifer underlying an MGP site in the upper Midwest region of the United States were studied through characterization, monitoring, and modeling of a plume of cyanide-contaminated groundwater emanating from the site. Results indicate that cyanide in the groundwater is primarily in the form of iron-cyanide complexes (>98%), that these complexes are stable under the conditions of the aquifer, and that they are transported as nonreactive solutes in the sand-gravel aquifer material. Weak-acid-dissociable cyanide, which represents a minute fraction of total cyanide in the site groundwater, may undergo chemical-biological degradation in the sand-gravel aquifer. It seems that dilution may be the only natural attenuation mechanism for iron-cyanide complexes in sand-gravel aquifers at MGP sites.