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Biochimica Et Biophysica Acta May 1995Mitochondrial function is closely linked to the maintenance of mitochondrial integrity. During short-term anoxia, ion-transport systems in the inner membrane are... (Review)
Review
Mitochondrial function is closely linked to the maintenance of mitochondrial integrity. During short-term anoxia, ion-transport systems in the inner membrane are inhibited to protect against loss of the promotive force and associated osmotic imbalance that can cause irreversible loss of mitochondrial integrity and function. In two models of chemically induced mitochondrial failure, a prostaglandin B1 derivative, di-calciphor, protected against mitochondrial failure and prevented cell death. Characteristics were similar to those observed in mitochondria during short-term anoxia. Thus, the results indicate that di-calciphor may represent a new type of mitochondrial protectant that inhibits ion transport and thus slows the loss of osmotic stability and delays mitochondrial dysfunction under traumatic and toxicologic conditions.
Topics: Animals; Cell Death; Cell Hypoxia; Cell Survival; Cells; Humans; Liver; Mitochondria, Liver; Potassium Cyanide; Prostaglandins B; Rats
PubMed: 7599222
DOI: 10.1016/0925-4439(95)00006-p -
FEBS Letters Dec 2017Respiratory supercomplex factor (Rcf) 1 is a membrane-bound protein that modulates the activity of cytochrome c oxidase (CytcO) in Saccharomyces cerevisiae...
Respiratory supercomplex factor (Rcf) 1 is a membrane-bound protein that modulates the activity of cytochrome c oxidase (CytcO) in Saccharomyces cerevisiae mitochondria. To investigate this regulatory mechanism, we studied the interactions of CytcO with potassium cyanide (KCN) upon removal of Rcf1. While the addition of KCN to the wild-type mitochondria results in a full reduction of heme a, with the rcf1Δ mitochondria, a significant fraction remains oxidized. Upon addition of ascorbate in the presence of O and KCN, the reduction level of hemes a and b was a factor of ~ 2 larger with the wild-type than with the rcf1Δ mitochondria. These data indicate that turnover of CytcO was less blocked in rcf1Δ than in the wild-type mitochondria, suggesting that Rcf1 modulates the structure of the catalytic site.
Topics: Catalytic Domain; Electron Transport; Electron Transport Complex IV; Mitochondria; Organisms, Genetically Modified; Oxidation-Reduction; Oxygen; Potassium Cyanide; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins
PubMed: 29171870
DOI: 10.1002/1873-3468.12918 -
BioMed Research International 2017Next-generation DNA sequencing (NGS) has made it feasible to sequence large number of microbial genomes and advancements in computational biology have opened enormous...
Next-generation DNA sequencing (NGS) has made it feasible to sequence large number of microbial genomes and advancements in computational biology have opened enormous opportunities to mine genome sequence data for novel genes and enzymes or their sources. In the present communication in silico mining of microbial genomes has been carried out to find novel sources of nitrilases. The sequences selected were analyzed for homology and considered for designing motifs. The manually designed motifs based on amino acid sequences of nitrilases were used to screen 2000 microbial genomes (translated to proteomes). This resulted in identification of one hundred thirty-eight putative/hypothetical sequences which could potentially code for nitrilase activity. In vitro validation of nine predicted sources of nitrilases was done for nitrile/cyanide hydrolyzing activity. Out of nine predicted nitrilases, , , , and were specific for aliphatic nitriles, whereas nitrilases from , , , and possessed activity for aromatic nitriles. was specific towards potassium cyanide (KCN) which revealed the presence of nitrilase homolog, that is, cyanide dihydratase with no activity for either aliphatic, aromatic, or aryl nitriles. The present study reports the novel sources of nitrilases and cyanide dihydratase which were not reported hitherto by in silico or in vitro studies.
Topics: Aminohydrolases; Bacteria; Bacterial Proteins; Genome, Bacterial; High-Throughput Nucleotide Sequencing; Sequence Analysis, DNA
PubMed: 28497061
DOI: 10.1155/2017/7039245 -
The Journal of Biological Chemistry Aug 1998Cyanide can potentiate N-methyl-D-aspartate receptor-mediated physiological responses in neurons. Here we show that this phenomenon may be attributable to a...
Cyanide can potentiate N-methyl-D-aspartate receptor-mediated physiological responses in neurons. Here we show that this phenomenon may be attributable to a subunit-specific chemical modification of the receptor directly by the toxin. N-Methyl-D-aspartate (30 microM)-induced whole cell responses in mature (22-29 days in vitro) rat cortical neurons were potentiated nearly 2-fold by a 3-5-min treatment with 2 mM potassium cyanide, as did a similar treatment with 4 mM dithiothreitol. A 1-min incubation with the thiol oxidant 5,5'-dithiobis(2-nitrobenzoic acid) (0.5 mM) readily reversed the potentiation induced by either cyanide or dithiothreitol. Cyanide did not increase further currents previously potentiated by dithiothreitol nor was it able to potentiate responses during brief co-application with the agonist. Transient expression studies in Chinese hamster ovary cells with wild-type and mutated recombinant N-methyl-D-aspartate subunits (NR) demonstrated that cyanide selectively potentiated NR1/NR2A receptors, presumably via the chemical reduction of NR2A. In contrast, currents mediated by NR1/NR2B receptors were somewhat diminished by the metabolic inhibitor. Some of the effects of cyanide on NR1/NR2B receptors may be mediated by the formation of a thiocyanate adduct with a cysteine residue located in NR1. Cyanide thus is able to distinguish chemically between two different N-methyl-D-aspartate receptor subtypes and produce diametrically opposing functional effects.
Topics: Animals; CHO Cells; Cricetinae; Dithionitrobenzoic Acid; Drug Synergism; Excitatory Amino Acid Antagonists; N-Methylaspartate; Neurons; Oxidation-Reduction; Potassium Cyanide; Rats; Receptors, N-Methyl-D-Aspartate; Sulfhydryl Reagents; Zinc
PubMed: 9705279
DOI: 10.1074/jbc.273.34.21505 -
Arhiv Za Higijenu Rada I Toksikologiju Mar 2014The aim of this investigation was to study whether certain bacteria could be used for cyanide degradation in soil. The bacteria Pseudomonas stutzeri and Bacillus...
The aim of this investigation was to study whether certain bacteria could be used for cyanide degradation in soil. The bacteria Pseudomonas stutzeri and Bacillus subtilis were selected based on their good growth in a minimal medium containing 0.8 mg mL-1 potassium cyanide (KCN). In this study we tested their ability to reduce cyanide levels in a medium containing 1.5 mg mL-1 of KCN. Although both microorganisms reduced cyanide levels, Pseudomonas stutzeri was the more effective test organism. Later on, the selected cultures were grown, diluted and their various cell concentrations were used individually and in combination to test their ability of cyanide degradation in soil samples collected around a cassava processing mill. Bacillus subtilis caused degradation of soil cyanide from 0.218 mg g-1 soil immediately with an inoculum concentration of 0.1 (OD600nm) to 0.072 mg g-1 soil after 10 days with an inoculum concentration of 0.6 (OD600nm) implying a 66.9 % reduction. Pseudomonas stutzeri cell concentration of 0.1 (OD600nm) decreased soil cyanide from 0.218 mg g-1 soil initially to 0.061 mg g-1 soil after 10 days with an inoculum concentration of 0.6 (OD600nm) (72 % reduction). The mixed culture of the two bacteria produced the best degradation of soil cyanide from 0.218 mg g-1 soil sample with a combined inoculum concentration of 0.1 (OD600nm) initially to 0.025 mg g-1 soil with a combined inoculum concentration of 0.6 (OD600nm) after 10 days incubation resulting in an 88.5 % degradation of soil cyanide. The analysed bacteria displayed high cyanide degradation potential and may be useful for efficient decontamination of cyanide contaminated sites.
Topics: Bacillus subtilis; Biodegradation, Environmental; Coculture Techniques; Cyanides; Pseudomonas stutzeri; Soil Microbiology; Soil Pollutants
PubMed: 24670334
DOI: 10.2478/10004-1254-65-2014-2449 -
Chemical Research in Toxicology Sep 2022Masitinib is a small molecule tyrosine kinase inhibitor under investigation for the treatment of amyotrophic lateral sclerosis, mastocytosis, and COVID-19....
Masitinib is a small molecule tyrosine kinase inhibitor under investigation for the treatment of amyotrophic lateral sclerosis, mastocytosis, and COVID-19. Hepatotoxicity has been reported in some patients while taking masitinib. The liver injury is thought to involve hepatic metabolism of masitinib by cytochrome P450 (P450) enzymes to form chemically reactive, potentially toxic metabolites. The goal of the current investigation was to determine the P450 enzymes involved in the metabolic activation of masitinib in vitro. In initial studies, masitinib (30 μM) was incubated with pooled human liver microsomes in the presence of NADPH and potassium cyanide to trap reactive iminium ion metabolites as cyano adducts. Masitinib metabolites and cyano adducts were analyzed using reversed-phase liquid chromatography-tandem mass spectrometry. The primary active metabolite, -desmethyl masitinib (M485), and several oxygenated metabolites were detected along with four reactive metabolite cyano adducts (MCN510, MCN524, MCN526, and MCN538). To determine which P450 enzymes were involved in metabolite formation, reaction phenotyping experiments were conducted by incubation of masitinib (2 μM) with a panel of recombinant human P450 enzymes and by incubation of masitinib with human liver microsomes in the presence of P450-selective chemical inhibitors. In addition, enzyme kinetic assays were conducted to determine the relative kinetic parameters (apparent and ) of masitinib metabolism and cyano adduct formation. Integrated analysis of the results from these experiments indicates that masitinib metabolic activation is catalyzed primarily by P450 3A4 and 2C8, with minor contributions from P450 3A5 and 2D6. These findings provide further insight into the pathways involved in the generation of reactive, potentially toxic metabolites of masitinib. Future studies are needed to evaluate the impact of masitinib metabolism on the toxicity of the drug in vivo.
Topics: Activation, Metabolic; Benzamides; COVID-19; Catalysis; Cytochrome P-450 Enzyme System; Humans; Microsomes, Liver; NADP; Piperidines; Potassium Cyanide; Protein Kinase Inhibitors; Pyridines; Thiazoles
PubMed: 36048877
DOI: 10.1021/acs.chemrestox.2c00057 -
PloS One 2018Cyanide fishing, where a solution of sodium or potassium cyanide is used to stun reef fish for easy capture for the marine aquarium and live fish food trades, continues...
Cyanide fishing, where a solution of sodium or potassium cyanide is used to stun reef fish for easy capture for the marine aquarium and live fish food trades, continues to be pervasive despite being illegal in many countries and destructive to coral reef ecosystems. Currently, there is no easy, reliable and universally accepted method to detect if a fish has been exposed to cyanide during the capture process. A promising non-invasive technique for detecting thiocyanate ions, the metabolic byproduct excreted by exposed fish, has been reported in the literature. In an effort to validate this method, four cyanide exposure studies on Amphiprion ocellaris (common clownfish) were carried out over three years. Fish were either exposed to the same (25 ppm) or twice the concentration (50 ppm) as the previsouly published method. Over 100 water samples of fish exposed to cyanide were analyzed by reverse phase HPLC with a C30 column treated with polyethylene glycol and UV detector operating at 220 nm. No thiocyanate was detected beyond the analytical standards and positive controls prepared in seawater. As an alternate means of detecting thiocyanate, water samples and thiocyanate standards from these exposures were derivatized with monobromobimane (MBB) for LC-MS/MS analysis. Thiocyanate was detected in standards with concentrations as low as 0.6 μg/L and quantified to 1 μg/L, but thiocyanate could not be detected in any of the water samples from fish exposed to cyanide with this method either, confirming the HPLC results. Further, we calculated both the mass balance of thiocyanate and the resultant plausible dosage of cyanide from the data reported in the previously published method. These calculations, along with the known lethal dosage of cyanide, further suggests that the detection of thiocyanate in aquarium water is not a viable method for assessing fish exposure to cyanide.
Topics: Animals; Chromatography, High Pressure Liquid; Coral Reefs; Cyanides; Perciformes; Potassium Cyanide; Seawater; Sodium Cyanide; Thiocyanates
PubMed: 29847597
DOI: 10.1371/journal.pone.0196841 -
Comparative Medicine Oct 2018Cyanide is a readily available and potentially lethal substance. Oral exposure can result in larger doses, compared with other routes. Currently, there are no antidotes...
Cyanide is a readily available and potentially lethal substance. Oral exposure can result in larger doses, compared with other routes. Currently, there are no antidotes specific for use in the treatment of oral cyanide poisoning, and studies cannot be done in humans. We report on a new large animal model of oral cyanide toxicity to evaluate potential antidotes. Six female swine (; weight, 45 to 55 kg) were anesthetized, intubated, and instrumented. Animals received a KCN bolus of either 5 or 8 mg/kg delivered via orogastric tube. Time to apnea was recorded; parameters monitored included heart rate, respiratory rate, blood pressure, pulse oximetry, end-tidal CO2, arterial blood gasses, and lactate concentrations. The Welch test was used to calculate confidence intervals, mean, and standard deviation, and a Kaplan-Meier survival curve was used to compare survival between the 2 groups. At baseline, all animals in both groups were similar. Animals in the 5-mg/kg group had a more rapid time to apnea (5.1 ± 2.1 min), longer time to death (48.5 ± 38.1 min), and a greater rate of survival than the 8-mg/kg group (apnea, 10.6 ± 10.7 min; death, 26.1 ± 5.8 min). All animals displayed signs of toxicity (acidemia, hyperlactatemia, hypotension, apnea). We here report a large animal (swine) model of oral cyanide poisoning with dose-dependent effects in regard to time to death and survival rate. This model likely will be valuable for the development of medical countermeasures for oral cyanide poisoning.
Topics: Administration, Oral; Animals; Disease Models, Animal; Female; Kaplan-Meier Estimate; Monitoring, Physiologic; Potassium Cyanide; Swine
PubMed: 30208987
DOI: 10.30802/AALAS-CM-18-000041 -
Journal of Analytical Toxicology Jul 2018A man was found dead in a hotel located near Rome (Italy). The man was still holding a syringe attached to a butterfly needle inserted in his left forearm vein. The...
A man was found dead in a hotel located near Rome (Italy). The man was still holding a syringe attached to a butterfly needle inserted in his left forearm vein. The syringe contained a cloudy pinkish fluid. In the hotel room the Police found a broken propofol glass vial plus four sealed ones, an opened NaCl plastic vial and six more still sealed, and a number of packed smaller disposable syringes and needles. An opened plastic bottle containing a white crystalline powder labeled as potassium cyanide was also found. Systematic toxicological analysis (STA), carried out on blood, urine and bile, evidenced only the presence of propofol in blood and bile. So the validated L-L extraction protocol and the GC/MS-TOF method for the confirmation of propofol in the biological fluids optimized in our laboratory was applied to blood, urine and bile. The concentration of propofol resulted to be 0.432 μg/mL in blood and 0.786 μg/mL in bile. The quantitative determination of cyanide in blood was carried out by microdiffusion technique coupled to spectrophotometric detection obtaining a cyanide concentration of 5.3 μg/mL. The quantitative determination was then confirmed by GC/NPD and the concentration of cyanide resulted to be 5.5 μg/mL in blood and 1.7 μg/mL in bile. Data emerging from autopsy findings, histopathological exams and the concentrations of cyanide suggested that death might be due to poisoning caused by cyanide, however, respiratory depression caused by propofol could not be excluded.
Topics: Adult; Autopsy; Bile; Cause of Death; Chromatography, Gas; Drug Overdose; Fatal Outcome; Forensic Toxicology; Gas Chromatography-Mass Spectrometry; Humans; Male; Potassium Cyanide; Predictive Value of Tests; Propofol; Spectrophotometry, Ultraviolet; Substance Abuse Detection
PubMed: 30007331
DOI: 10.1093/jat/bky015 -
Shock (Augusta, Ga.) Mar 2017Our objective was to determine how circulatory failure develops following systemic administration of potassium cyanide (KCN). We used a noninhaled modality of...
Our objective was to determine how circulatory failure develops following systemic administration of potassium cyanide (KCN). We used a noninhaled modality of intoxication, wherein the change in breathing pattern would not influence the diffusion of CN into the blood, akin to the effects of ingesting toxic levels of CN. In a group of 300 to 400 g rats, CN-induced coma (CN i.p., 7 mg/kg) produced a central apnea within 2 to 3 min along with a potent and prolonged gasping pattern leading to autoresuscitation in 38% of the animals. Motor deficits and neuronal necrosis were nevertheless observed in the surviving animals. To clarify the mechanisms leading to potential autoresuscitation versus asystole, 12 urethane-anesthetized rats were then exposed to the lowest possible levels of CN exposure that would lead to breathing depression within 7 to 8 min; this dose averaged 0.375 mg/kg/min i.v. At this level of intoxication, a cardiac depression developed several minutes only after the onset of the apnea, leading to cardiac asystole as PaO2 reached value approximately 15 Torr, unless breathing was maintained by mechanical ventilation or through spontaneous gasping. Higher levels of KCN exposure in 10 animals provoked a primary cardiac depression, which led to a rapid cardiac arrest by pulseless electrical activity (PEA) despite the maintenance of PaO2 by mechanical ventilation. These effects were totally unrelated to the potassium contained in KCN. It is concluded that circulatory failure can develop as a direct consequence of CN-induced apnea but in a narrow range of exposure. In this "low" range, maintaining pulmonary gas exchange after exposure, through mechanical ventilation (or spontaneous gasping), can reverse cardiac depression and restore spontaneous breathing. At higher level of intoxication, cardiac depression is to be treated as a specific and spontaneously irreversible consequence of CN exposure, leading to a PEA.
Topics: Animals; Apnea; Blood Gas Analysis; Cyanides; Male; Potassium Chloride; Pulmonary Gas Exchange; Rats; Rats, Sprague-Dawley; Shock
PubMed: 27513083
DOI: 10.1097/SHK.0000000000000732