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Plant, Cell & Environment Nov 2012The effects of potassium cyanide (KCN) pretreatment on the response of cucumber (Cucumis sativus L.) plants to salt, polyethylene glycol (PEG) and cold stress were...
The effects of potassium cyanide (KCN) pretreatment on the response of cucumber (Cucumis sativus L.) plants to salt, polyethylene glycol (PEG) and cold stress were investigated in the present study. Here, we found that KCN pretreatment improved cucumber seedlings tolerance to stress conditions with maximum efficiency at a concentration of 20 µM. The results showed that pretreatment with 20 µM KCN alleviated stress-induced oxidative damage in plant cells and clearly induced the activity of alternative oxidase (AOX) and the ethylene production. Furthermore, the structures of thylakoids and mitochondria in the KCN-pretreated seedlings were less damaged by the stress conditions, which maintained higher total chlorophyll content, photosynthetic rate and photosystem II (PSII) proteins levels than the control. Importantly, the addition of the AOX inhibitor salicylhydroxamic acid (1 mm; SHAM) decreased plant resistance to environmental stress and even compromised the cyanide (CN)-enhanced stress tolerance. Therefore, our findings provide a novel role of CN in plant against environmental stress and indicate that the CN-enhanced AOX might contribute to the reactive oxygen species (ROS) scavenging and the protection of photosystem by maintaining energy charge homoeostasis from chloroplast to mitochondria.
Topics: Antioxidants; Cucumis sativus; Ethylenes; Oxidative Stress; Potassium Cyanide; Reactive Oxygen Species; Seedlings; Stress, Physiological
PubMed: 22554042
DOI: 10.1111/j.1365-3040.2012.02531.x -
Annals of the New York Academy of... Nov 2020The aim of the present study was to determine whether methylene blue (MB) could directly oppose the neurological toxicity of a lethal cyanide (CN) intoxication. KCN,...
The aim of the present study was to determine whether methylene blue (MB) could directly oppose the neurological toxicity of a lethal cyanide (CN) intoxication. KCN, infused at the rate of 0.375 mg/kg/min intravenously, produced 100% lethality within 15 min in unanaesthetized rats (n = 12). MB at 10 (n = 5) or 20 mg/kg (n = 5), administered 3 min into CN infusion, allowed all animals to survive with no sequelae. No apnea and gasping were observed at 20 mg/kg MB (P < 0.001). The onset of coma was also significantly delayed and recovery from coma was shortened in a dose-dependent manner (median of 359 and 737 seconds, respectively, at 20 and 10 mg/kg). At 4 mg/kg MB (n = 5), all animals presented faster onset of coma and apnea and a longer period of recovery than at the highest doses (median 1344 seconds, P < 0.001). MB reversed NaCN-induced resting membrane potential depolarization and action potential depression in primary cultures of human fetal neurons intoxicated with CN. MB restored calcium homeostasis in the CN-intoxicated human SH-SY5Y neuroblastoma cell line. We conclude that MB mitigates the neuronal toxicity of CN in a dose-dependent manner, preventing the lethal depression of respiratory medullary neurons and fatal outcome.
Topics: Animals; Antidotes; Cell Line, Tumor; Dose-Response Relationship, Drug; Humans; Male; Methylene Blue; Neurons; Neurotoxicity Syndromes; Potassium Cyanide; Rats; Rats, Sprague-Dawley
PubMed: 32374444
DOI: 10.1111/nyas.14353 -
The Journal of Toxicological Sciences 2019This study was aimed to predict drug-induced liver injury caused by reactive metabolites. Reactive metabolites covalently bind to proteins and could result in severe...
This study was aimed to predict drug-induced liver injury caused by reactive metabolites. Reactive metabolites covalently bind to proteins and could result in severe outcomes in patients. However, the relation between the extent of covalent binding and clinical hepatotoxicity is still unclear. From a perspective of body burden (human in vivo exposure to reactive metabolites), we developed a risk assessment method in which reactive metabolite burden (RM burden), an index that could reflect the body burden associated with reactive metabolite exposure, is calculated using the extent of covalent binding, clinical dose, and human in vivo clearance. The relationship between RM burden and hepatotoxicity in humans was then investigated. The results indicated that this RM burden assessment exhibited good predictability for sensitivity and specificity, and drugs with over 10 mg/day RM burden have high-risk for hepatotoxicity. Furthermore, a quantitative trapping assay using radiolabeled trapping agents ([S]cysteine and [C]KCN) was also developed, to detect reactive metabolite formation in the early drug discovery stage. RM burden calculated using this assay showed as good predictability as RM burden calculated using conventional time- and cost-consuming covalent binding assays. These results indicated that the combination of RM burden and our trapping assay would be a good risk assessment method for reactive metabolites from the drug discovery stage.
Topics: Body Burden; Chemical and Drug Induced Liver Injury; Cysteine; Drug Discovery; Humans; Microsomes, Liver; Pharmaceutical Preparations; Potassium Cyanide; Risk Assessment
PubMed: 30842372
DOI: 10.2131/jts.44.201 -
Endocrinologia Japonica Oct 1980Rat hepatoma cells (R117-21B) metabolized 3,3'diiodothyronine and 3'-monoiodothyronine by sulfation and glucuronidation. Glucuronidation of iodothyronines (a mixture of...
Metabolism of 3,3'-Diiodothyronine and 3'-monoiodothyronine, and effect of potassium cyanide and dinitrophenol and glucuronidation of thyroxine in cultured rat hepatoma cells.
Rat hepatoma cells (R117-21B) metabolized 3,3'diiodothyronine and 3'-monoiodothyronine by sulfation and glucuronidation. Glucuronidation of iodothyronines (a mixture of 3,3'-diiodothyronine, approximately 99%, and 3'-monoiodothyronine, approximately 10%(was very rapid and 83% of the total 125I in the medium was their glucuronides after 8 hr incubation with the cells at 37 degrees C. Iodothyronine sulfates (approximately 9% of the total 125I) were also detected. No clear increase in free iodide was observed during the 8 hr incubation. The effect of KCN or dinitrophenol on glucuronidation of thyroxine was investigated. Both drugs inhibited glucuronidation, and dinitrophenol was more effective than KCN. Dinitrophenol accelerated the liberation of 125I- in the metabolism of thyroxine in the cultured rat hepatoma cells.
Topics: Animals; Cells, Cultured; Cyanides; Diiodothyronines; Dinitrophenols; Glucuronates; Liver Neoplasms, Experimental; Potassium Cyanide; Rats; Thyronines; Thyroxine
PubMed: 7238420
DOI: 10.1507/endocrj1954.27.631 -
The Journal of General Physiology Mar 1956The effects of several inhibitors on the rates of photosynthesis and of respiration by Chlorella pyrenoidosa have been studied. The inhibitors used in this study include...
The effects of several inhibitors on the rates of photosynthesis and of respiration by Chlorella pyrenoidosa have been studied. The inhibitors used in this study include potassium cyanide, hydroxylamine hydrogen chloride, dinitrophenol,and sodium azide. Each inhibitor seems to have its own characteristic action in photosynthesis and in respiration. With the exception of hydroxylamine, all the inhibitors show a stimulation of respiration at low concentrations of the inhibitors. Only dinitrophenol inhibits respiration to a marked extent. Potassium cyanide, hydroxylamine, and dinitrophenol are about equally effective in inhibiting photosynthesis, but sodium azide is nearly ten times as effective.
Topics: Cell Respiration; Chlorella; Eukaryota; Photosynthesis
PubMed: 13295552
DOI: 10.1085/jgp.39.4.527 -
The Journal of Clinical Investigation Oct 1983The sensitivity of the brain to cyanide-induced histotoxic hypoxia and the protective effects of known cyanide antagonists, have been assessed in vivo by reflectance...
The sensitivity of the brain to cyanide-induced histotoxic hypoxia and the protective effects of known cyanide antagonists, have been assessed in vivo by reflectance spectrophotometry. Cyanide-related changes in cytochrome a,a3 (cytochrome c oxidase) oxidation-reduction (redox) state, tissue hemoglobin saturation, and local blood volume were continuously monitored in cerebral cortex of rats. Noncumulative, dose-dependent inhibition of the in situ mitochondrial respiratory chain was evaluated directly by measuring increases in reduction levels of the terminal oxidase. These transient cytochrome a,a3 reductions were accompanied by increases in regional cerebral hemoglobin saturation and blood volume. Cytochrome redox responses were not altered either in magnitude or kinetics by hyperoxia; however, the cyanide-cytochrome dose-response curve was greatly shifted to the right by pretreatment with sodium nitrite, and the recovery rate of cytochrome a,a3 from cyanide-induced reduction was enhanced fourfold by pretreatment with sodium thiosulfate.
Topics: Animals; Blood Volume; Brain; Cyanides; Dose-Response Relationship, Drug; Electron Transport Complex IV; Hypotension; Male; Methemoglobin; Oxidation-Reduction; Oxygen; Oxyhemoglobins; Potassium Cyanide; Rats; Rats, Inbred Strains; Thiosulfates
PubMed: 6313756
DOI: 10.1172/JCI111078 -
The Biochemical Journal Oct 1983Optical-absorption-, e.p.r.- and m.c.d. (magnetic-circular-dichroism)-spectroscopic measurements were made on liganded derivatives of oxidized and partially reduced...
Optical-absorption-, e.p.r.- and m.c.d. (magnetic-circular-dichroism)-spectroscopic measurements were made on liganded derivatives of oxidized and partially reduced cytochrome c oxidase. When NO was added to oxidized cyanide-bound cytochrome c oxidase, no changes occurred in the optical-absorption difference spectrum. In contrast, NO induced reduction of cytochrome a3 and formation of the nitrosylferrohaem species when the oxidized resting enzyme was the starting material. E.p.r. spectroscopy of the NO-treated oxidized cyanide-bound enzyme revealed the presence of a low-spin haem signal at g = 3.40, whereas the g = 3.02 and g = 2.0 signals of the oxidized enzyme remained unchanged. Both haem groups in this species are e.p.r.-detectable simultaneously. Examination of an identical sample by m.c.d. spectroscopy in the near-i.r. region identified two distinct low-spin species at 1565 and 1785 nm. Irradiation with white light of the NO-treated cyanide-bound sample at 10K resulted in the disappearance of the g = 3.40 e.p.r. signal and the m.c.d. signal at 1785 nm, whereas a band at 1950nm increased in intensity. When the photolysed sample was warmed to 50K and held in the dark for 15 min, the original spectrum returned. Magnetization studies of the 1785nm m.c.d. band support the assignment of this signal to the same metal centre that gives rise to the g = 3.40 e.p.r. signal. The effect of NO on the oxidized cyanide-bound enzyme was compared with that obtained when the oxidized cyanide-bound species was taken to the partially reduced state. Cytochrome a3 is e.p.r.-detectable with a g-value of 3.58 [Johnson, Eglinton, Gooding, Greenwood & Thomson (1981) Biochem. J. 193, 699-708]. Its near-i.r. m.c.d. spectrum shifts from 1950nm in the oxidized cyanide-bound enzyme to 1545nm on addition of reductant. A scheme is advanced for the structure of the cytochrome a3-CuB site that allows for cyanide binding to Fea3 and NO binding to CuB. Cyanide is the bridging ligand in the ferromagnetically coupled cytochrome a3-CuB pair of oxidized cyanide-bound cytochrome c oxidase. The bridged structure and the magnetic interaction are broken when the enzyme is partially reduced. However, when NO binds to CuB the cyanide bridge remains intact, but now the odd spins of NO and CuB are magnetically coupled.
Topics: Animals; Cattle; Circular Dichroism; Copper; Cyanides; Electron Spin Resonance Spectroscopy; Electron Transport Complex IV; Ferric Compounds; Ligands; Nitric Oxide; Oxidation-Reduction; Potassium Cyanide; Spectrophotometry; Temperature
PubMed: 6312973
DOI: 10.1042/bj2150057 -
ACS Omega Dec 2017Herein, we report the modulation of ZnO for enhancement of its ability toward plasmonic absorption of near-infrared (NIR) photons through coupling of graphene (GR). The...
Herein, we report the modulation of ZnO for enhancement of its ability toward plasmonic absorption of near-infrared (NIR) photons through coupling of graphene (GR). The reported modification led GR-ZnO to be a promising photocatalyst by the complete removal of poisonous and nonvolatile potassium cyanide from water. The photocatalytic degradation of cyanide was revealed by exposing it to NIR laser and comparing with the rate of UV, visible, and sunlight using their apparent reaction rate constants derived from the Langmuir-Hinshelwood model. The heteronanostructured GR-ZnO promoted rapid photo-oxidation of cyanide under illumination with NIR laser rather than UV, visible, and sunlight. It was assessed that the photothermal effect (PTE) is the main cause for higher catalytic efficiency of GR-ZnO in the presence of NIR radiations. Except for the NIR radiations, GR-ZnO does not show any indication of PTE by irradiating with UV, visible, or sunlight. On account of its significance, the PTE of GR-ZnO in KCN solution was evaluated and compared with its individual components viz., GR and ZnO upon exposure to a 980 nm laser system. Furthermore, it has been revealed that the PTE of GR-ZnO was proportional to its concentration. In addition to its effectiveness in the degradation of cyanide, GR-ZnO retained its special structure and exhibited an outstanding photostability after its repeated use in three successive cycles.
PubMed: 29302633
DOI: 10.1021/acsomega.7b01398 -
The Biochemical Journal Apr 1980Rat and pigeon heart mitochondria supplemented with antimycin produce 0.3-1.0nmol of H(2)O(2)/min per mg of protein. These rates are stimulated up to 13-fold by addition...
Rat and pigeon heart mitochondria supplemented with antimycin produce 0.3-1.0nmol of H(2)O(2)/min per mg of protein. These rates are stimulated up to 13-fold by addition of protophores (carbonyl cyanide p-trifluoromethoxyphenylhydrazone, carbonyl cyanide m-chloromethoxyphenylhydrazone and pentachlorophenol). Ionophores, such as valinomycin and gramicidin, and Ca(2+) also markedly stimulated H(2)O(2) production by rat heart mitochondria. The enhancement of H(2)O(2) generation in antimycin-supplemented mitochondria and the increased O(2) uptake of the State 4-to-State 3 transition showed similar protophore, ionophore and Ca(2+) concentration dependencies. Thenoyltrifluoroacetone and N-bromosuccinimide, which inhibit succinate-ubiquinone reductase activity, also decreased mitochondrial H(2)O(2) production. Addition of cyanide to antimycin-supplemented beef heart submitochondrial particles inhibited the generation of O(2) (-), the precursor of mitochondrial H(2)O(2). This effect was parallel to the increase in cytochrome c reduction and it is interpreted as indicating the necessity of cytochrome c(1) (3+) to oxidize ubiquinol to ubisemiquinone, whose autoxidation yields O(2) (-). The effect of protophores, ionophores and Ca(2+) is analysed in relation to the propositions of a cyclic mechanism for the interaction of ubiquinone with succinate dehydrogenase and cytochromes b and c(1) [Wikstrom & Berden (1972) Biochim. Biophys. Acta283, 403-420; Mitchell (1976) J. Theor. Biol.62, 337-367]. A collapse in membrane potential, increasing the rate of ubisemiquinone formation and O(2) (-) production, is proposed as the molecular mechanism for the enhancement of H(2)O(2) formation rates observed on addition of protophores, ionophores and Ca(2+).
Topics: Adenosine Triphosphate; Animals; Antimycin A; Bromosuccinimide; Calcium; Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; Columbidae; Hydrogen Peroxide; In Vitro Techniques; Ionophores; Mitochondria, Heart; Nitriles; Potassium Cyanide; Rats; Thenoyltrifluoroacetone
PubMed: 7406888
DOI: 10.1042/bj1880031 -
The Journal of Biophysical and... May 1957The finding of Lilly and Thoday that potassium cyanide produces structural chromosome changes in root tips of Vicia faba was confirmed. Like mustards, diepoxides, and...
The finding of Lilly and Thoday that potassium cyanide produces structural chromosome changes in root tips of Vicia faba was confirmed. Like mustards, diepoxides, and maleic hydrazide, potassium cyanide seems to act on cells at early interphase. A tendency of cyanide breaks to be concentrated in heterochromatic segments of the chromosomes was evident. The production of chromosome aberrations by cyanide proved to be practically unaffected by the temperature during treatment. In agreement with Lilly and Thoday, the effect of potassium cyanide was found to be dependent on oxygen tension during treatment. The effect of potassium cyanide increases with increasing oxygen concentration up to 100 per cent oxygen. In the absence of oxygen, potassium cyanide was not completely inactive, but produced a low, though significant frequency of aberrations. Pretreatments with 2.4-dinitrophenol did not influence the effect of potassium cyanide. When bean roots were treated with potassium cyanide before a treatment with 8-ethoxycaffeine, or at the same time as they were treated with 8-ethoxycaffeine, the effect of 8-ethoxycaffeine was almost completely suppressed. The effects of a number of other heavy metal complexing agents were also tested. Sodium fluoride, potassium thiocyanate, carbon monoxide, o-phenanthroline, 2.2-bipyridine, and sodium azide were without radiomimetic effect under the conditions employed, and so was a mixture of sodium azide and sodium fluoride. A low, but quite significant, radiomimetic effect was obtained after treatments with sodium diethyldithiocarbamate, cupferron, and 8-hydroxyquinoline. Under anaerobic conditions, the effects of cyanide and cupferron were both quantitatively and qualitatively indistinguishable. Unlike the effect of cyanide, the effect of cupferron was not enhanced by the presence of oxygen. The effects of the same heavy metal complexing agents were tested on the activities of the enzymes catalase and peroxidase. The activities of both of these enzymes were found to be totally inhibited only by potassium cyanide. In the other cases, little correlation was found between ability to inhibit the activities of these enzymes and ability to produce chromosome aberrations. In a number of experiments, hydrogen peroxide was found to be without radiomimetic effect, whether alone or in combination with potassium cyanide. t-Butyl hydroperoxide proved to be active. The effect of t-butyl hydroperoxide was substantially increased by pretreatments with 2.4.-dinitrophenol. The results are discussed, and it is concluded that the observations made do not support the hypothesis that hydrogen peroxide is involved in the production of chromosome aberrations by potassium cyanide. The possibility that organic peroxides are involved cannot be excluded on the bases of the experimental results. As an alternative hypothesis, it is suggested that iron or other heavy metals are present in the chromosomes and that cyanide and other heavy metal complexing agents produce chromosome aberrations by reacting with these metals.
Topics: Caffeine; Catalase; Chromosome Aberrations; Chromosome Disorders; Chromosomes; Coordination Complexes; Cyanides; Fabaceae; Hydrocarbons; Metals; Metals, Heavy; Oxyquinoline; Peroxides; Phenanthrolines; Plants; tert-Butylhydroperoxide
PubMed: 13438921
DOI: 10.1083/jcb.3.3.363