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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 -
Biochimica Et Biophysica Acta Apr 2010A sodium ion efflux, together with a proton influx and an inside-positive DeltaPsi, was observed during NADH-respiration by Rhodothermus marinus membrane vesicles....
A sodium ion efflux, together with a proton influx and an inside-positive DeltaPsi, was observed during NADH-respiration by Rhodothermus marinus membrane vesicles. Proton translocation was monitored by fluorescence spectroscopy and sodium ion transport by (23)Na-NMR spectroscopy. Specific inhibitors of complex I (rotenone) and of the dioxygen reductase (KCN) inhibited the proton and the sodium ion transport, but the KCN effect was totally reverted by the addition of menaquinone analogues, indicating that both transports were catalyzed by complex I. We concluded that the coupling ion of the system is the proton and that neither the catalytic reaction nor the establishment of the delta-pH are dependent on sodium, but the presence of sodium increases proton transport. Moreover, studies of NADH oxidation at different sodium concentrations and of proton and sodium transport activities allowed us to propose a model for the mechanism of complex I in which the presence of two different energy coupling sites is suggested.
Topics: Bacterial Proteins; Cell Membrane; Electron Transport Complex I; Energy Transfer; Ion Transport; Magnetic Resonance Spectroscopy; NAD; Oxidoreductases; Oxygen; Oxygen Consumption; Potassium Cyanide; Proton-Motive Force; Protons; Rhodothermus; Rotenone; Sodium; Spectrometry, Fluorescence
PubMed: 20100453
DOI: 10.1016/j.bbabio.2010.01.020 -
The Journal of Physiology Mar 19891. The central end of the distally cut left carotid sinus nerve was sutured to the tunica media of the external carotid artery, 1 cm cranial to the carotid bifurcation,...
1. The central end of the distally cut left carotid sinus nerve was sutured to the tunica media of the external carotid artery, 1 cm cranial to the carotid bifurcation, in nineteen rabbits. The carotid body was removed in fourteen of these rabbits but left in situ in the remaining five. After 56-165 days of recovery a neuroma was identified at the site of the suture. Ventilatory reflexes mediated by both sinus nerves were tested and afferent activity recorded from the regenerated nerve. 2. Ventilatory reflex responses to hypoxia and sodium cyanide were abolished on sectioning the right sinus nerve, whilst the hypercapnic response was maintained. 3. Electrical stimulation of the regenerated sinus nerve caused hypotension and hyperventilation. These responses were attenuated compared to stimulation of the right sinus nerve. 4. A level of afferent activity equivalent to that found in non-regeneration experiments was recorded from all regenerated sinus nerves. Whole-nerve afferent activity was modulated by changes in carotid sinus blood pressure but not by changes in Pa,O2, Pa,CO2 (arterial O2 and CO2 pressures) or intracarotid injection of sodium cyanide. 5. A minimum of thirty single afferent fibres was identified in each experiment, the vast majority of which were mechanoreceptors. In only nine experiments were chemoreceptor fibres found and only twelve chemoreceptor fibres (1.7% of total) were identified in these nine experiments. In ten experiments no chemoreceptor fibres could be found. Leaving the carotid body in situ increased the incidence of chemoreceptive preparations. A small number of fibres unresponsive to mechanical stimulation and asphyxia was also identified. 6. The responses of regenerated chemoreceptor fibres to physiological and pharmacological stimuli were generally similar to those found in control carotid body preparations. Fibres unresponsive to mechanical stimulation and asphyxia did not respond to sodium cyanide, dopamine or isoprenaline; some of these fibres were excited by nicotine. 7. The receptive fields of mechanosensitive fibres were localized on or up to 2 cm away from the neuroma. Surface application of 20-40 microliters sodium cyanide (200 micrograms ml-1) was used to localize the receptive fields of seven of the twelve chemoreceptor fibres. All seven were localized to the site of the carotid body. 8. The neuroma and site of the carotid body were examined under light and electron microscopy. Glomus tissue was absent from the neuroma but was found at the site of the carotid body. 9. In conclusion, recovery of chemoreceptor function after carotid sinus nerve section appears to be associated with reinnervation of glomus tissue.
Topics: Action Potentials; Animals; Carotid Body; Carotid Sinus; Chemoreceptor Cells; Mechanoreceptors; Microscopy, Electron; Nerve Regeneration; Neurons, Afferent; Oxygen; Pressoreceptors; Rabbits; Respiration; Sodium Cyanide
PubMed: 2795484
DOI: 10.1113/jphysiol.1989.sp017541 -
Journal of Medicinal Chemistry Feb 2015Currently available cyanide antidotes must be given by intravenous injection over 5-10 min, making them ill-suited for treating many people in the field, as could occur...
Currently available cyanide antidotes must be given by intravenous injection over 5-10 min, making them ill-suited for treating many people in the field, as could occur in a major fire, an industrial accident, or a terrorist attack. These scenarios call for a drug that can be given quickly, e.g., by intramuscular injection. We have shown that aquohydroxocobinamide is a potent cyanide antidote in animal models of cyanide poisoning, but it is unstable in solution and poorly absorbed after intramuscular injection. Here we show that adding sodium nitrite to cobinamide yields a stable derivative (referred to as nitrocobinamide) that rescues cyanide-poisoned mice and rabbits when given by intramuscular injection. We also show that the efficacy of nitrocobinamide is markedly enhanced by coadministering sodium thiosulfate (reducing the total injected volume), and we calculate that ∼1.4 mL each of nitrocobinamide and sodium thiosulfate should rescue a human from a lethal cyanide exposure.
Topics: Animals; Antidotes; COS Cells; Chlorocebus aethiops; Cobamides; Cyanides; Dose-Response Relationship, Drug; Injections, Intramuscular; Male; Mice; Mice, Inbred C57BL; Muscle, Skeletal; Rabbits; Sodium Nitrite; Structure-Activity Relationship; Thiosulfates; Time Factors
PubMed: 25650735
DOI: 10.1021/jm501565k -
Journal of the American Chemical Society Aug 2023Protein α-N-terminal dimethylation (Nme) is an underexplored posttranslational modification (PTM) despite the increasing implications of α-N-terminal dimethylation in...
Protein α-N-terminal dimethylation (Nme) is an underexplored posttranslational modification (PTM) despite the increasing implications of α-N-terminal dimethylation in vital physiological and pathological processes across diverse species; thus, it is imperative to identify the sites of α-N-terminal dimethylation in the proteome. So far, only ∼300 α-N-terminal methylation sites have been discovered including mono-, di-, and tri-methylation, due to the lack of a pan-selective method for detecting α-N-terminal dimethylation. Herein, we introduce the three-component coupling reaction, oxidative nitrile thiazolidination (OxNiTha) for chemoselective modification of α-Nme to thiazolidine ring in the presence of selectfluor, sodium cyanide, and 1,2 aminothiols. One of the major challenges in developing a pan-specific method for the selective modification of α-Nme PTM is the competing reaction with dimethyl lysine (Kme) PTM of a similar structure. We tackle this challenge by trapping nitrile-modified Nme with aminothiols, leading to the conversion of Nme to a five-membered thiazolidine ring. Surprisingly, the 1,2 aminothiol reaction with nitrile-modified Kme led to de-nitrilation along with the de-methylation to generate monomethyl lysine (Kme). We demonstrated the application of OxNiTha reaction in pan-selective and robust modification of α-Nme in peptides and proteins to thiazolidine functionalized with varying fluorescent and affinity tags under physiological conditions. Further study with cell lysate enabled the enrichment of Nme PTM containing proteins.
Topics: Lysine; Nitriles; Thiazolidines; Protein Processing, Post-Translational; Proteome; Oxidative Stress
PubMed: 37486086
DOI: 10.1021/jacs.3c02369 -
Toxicity Report Series Nov 1993Cyanide and its salts are used extensively in industry and manufacturing and are found in water and food consumed by humans. Chronic exposure to low levels of cyanide is...
Cyanide and its salts are used extensively in industry and manufacturing and are found in water and food consumed by humans. Chronic exposure to low levels of cyanide is suspected to be responsible for various neuropathic and thyrotoxic conditions in humans. Data in the literature indicate that long-term exposure to near-lethal concentrations of cyanide may produce lesions in rodents similar to those linked to chronic cyanide exposure in humans. However, few data are available on the effects of subchronic exposure to cyanide concentrations that are not acutely toxic. To address this lack of data, 13-week toxicity studies on cyanide were conducted with male and female F344/N rats and B6C3F1 mice administered low doses of sodium cyanide in drinking water. Animals were evaluated for histopathology, clinical chemistry, hematology, urine chemistry, and reproductive toxicity. In addition, the mutagenicity of sodium cyanide was assessed in Salmonella typhimurium. Groups of 10 rats and 10 mice per sex were administered sodium cyanide in drinking water at concentrations of 0, 3, 10, 30, 100, and 300 ppm for 13 weeks. No deaths attributed to sodium cyanide administration occurred in either species. In animals exposed to 300 ppm, male rats had slightly lower final mean body weights and mean body weight gains and female mice had slightly lower final mean body weights than the respective controls. Water consumption by rats and mice in the 100 and 300 ppm groups was 10% to 30% lower than that by the controls; however, no clinical signs attributable to sodium cyanide administration or to dehydration were observed. No gross or microscopic changes specifically related to cyanide toxicity occurred at any site in males or females of either species. In particular, no lesions were found in the brain or thyroid gland. Differences between absolute and relative organ weights of exposed and control animals were minor and sporadic and were not exposure concentration dependent; these differences were not considered to be related to sodium cyanide administration. Hematologic, clinical chemistry, and urinalysis evaluations of rats and mice revealed minimal changes that were not considered biologically significant, although the decreased urine volume and increased urine specific gravity observed in male rats in the 300 ppm group of the supplemental clinical pathology study were consistent with the observed decreases in water consumption. The concentration of urinary thiocyanate (the primary metabolite of cyanide) increased with increasing exposure concentration at all time points. Sperm motility and vaginal cytology examinations were performed on rats and mice in the 0, 30, 100, and 300 ppm groups. Sodium cyanide caused a slight reduction in cauda epididymal weight in all groups of exposed male rats and in male mice exposed to 300 ppm. In male rats, the number of spermatid heads per testis in the 300 ppm group was less than the number in the controls, and sperm motility in all exposed groups was marginally lower than in the controls. Sodium cyanide produced no adverse effects on estrous cyclicity in female mice, but at higher concentrations (100 and 300 ppm), sodium cyanide caused a significant increase in the amount of time spent by female rats in proestrus and diestrus relative to estrus and metestrus. Sodium cyanide was not mutagenic in Salmonella typhimurium strain TA100, TA1535, TA97, or TA98 with or without exogenous metabolic activation. In summary, administration of low concentrations of sodium cyanide in drinking water to rats and mice for 13 weeks resulted in no clinically significant body weight, organ weight, histopathologic, or clinical pathology changes. The absorption of administered cyanide was confirmed by increases in urinary thiocyanate excretion. Concentrations of 100 ppm and greater resulted in reduced water consumption. Thus, higher concentrations of sodium cyanide could not be administered by the drinking water route of administration. Alterations in reproductive parameters indicate that subchronic exposure to low concentrations of sodium cyanide may produce mild but significant adverse effects on rat reproductive systems. These changes are probably insufficient to decrease fertility in rats; however, humans are considered to be relatively more sensitive to such changes than rats, and the potential for reproductive toxicity in humans from low concentrations of cyanide warrants further investigation. NOTE: These studies were supported in part by funds from the Comprehensive Environmental Response, Compensation, and Liability Act trust fund (Superfund) by an interagency agreement with the Agency for Toxic Substances and Disease Registry, U.S. Public Health Service.
PubMed: 11965236
DOI: No ID Found -
Toxicological Sciences : An Official... Jun 2010Cyanide inhibits aerobic metabolism by binding to the binuclear heme center of cytochrome c oxidase (CcOX). Amyl nitrite and sodium nitrite (NaNO(2)) antagonize cyanide...
Cyanide inhibits aerobic metabolism by binding to the binuclear heme center of cytochrome c oxidase (CcOX). Amyl nitrite and sodium nitrite (NaNO(2)) antagonize cyanide toxicity in part by oxidizing hemoglobin to methemoglobin (mHb), which then scavenges cyanide. mHb generation is thought to be a primary mechanism by which the NO(2)(-) ion antagonizes cyanide. On the other hand, NO(2)(-) can undergo biotransformation to generate nitric oxide (NO), which may then directly antagonize cyanide inhibition of CcOX. In this study, nitrite-mediated antagonism of cyanide inhibition of oxidative phosphorylation was examined in rat dopaminergic N27 cells. NaNO(2) produced a time- and concentration-dependent increase in whole-cell and mitochondrial levels of NO. The NO scavenger 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxy 3-oxide (PTIO) reversed this increase in cellular and mitochondrial NO. NO generated from NaNO(2) decreased cellular oxygen consumption and inhibited CcOX activity. PTIO reversed the NO-mediated inhibition, thus providing strong evidence that NO mediates the action of NaNO(2). Under similar conditions, KCN (20muM) inhibited cellular state-3 oxygen consumption and CcOX activity. Pretreatment with NaNO(2) reversed KCN-mediated inhibition of both oxygen consumption and CcOX activity. The NaNO(2) antagonism of cyanide was blocked by pretreatment with the NO scavenger PTIO. It was concluded that NaNO(2) antagonizes cyanide inhibition of CcOX by generating of NO, which then interacts directly with the binding of KCN x CcOX to reverse the toxicity. In vivo antagonism of cyanide by NO(2)(-) appears to be due to both generation of mHb and direct displacement of cyanide from CcOX by NO.
Topics: Animals; Cell Line, Transformed; Chemical Warfare Agents; Cyclic N-Oxides; Dopamine; Drug Antagonism; Electron Transport Complex IV; Free Radical Scavengers; Hydrogen Cyanide; Imidazoles; Neurons; Nitric Oxide; Nitric Oxide Donors; Rats; Sodium Nitrite
PubMed: 20335280
DOI: 10.1093/toxsci/kfq084 -
Experimental Physiology Feb 2023What is the central question of this study? What are the effects of insulin and insulin-induced hypoglycaemia on carotid body chemoreceptor activity in vivo and how do...
NEW FINDINGS
What is the central question of this study? What are the effects of insulin and insulin-induced hypoglycaemia on carotid body chemoreceptor activity in vivo and how do carotid body chemoreceptor stimulation-mediated cardiorespiratory responses in beagle dogs compare during euglycaemia and insulin-induced hypoglycaemia? What is the main finding and its importance? Intracarotid insulin administration leads to sustained increase in carotid body chemoreceptor activity and respiratory response with significant cardiovascular effects. Insulin-induced hypoglycaemia exacerbated NaCN-mediated carotid body chemoreceptor activity and respiratory response with enhanced cardiovascular reflex response. These findings suggest that insulin-induced hypoglycaemia augments the carotid body chemoreceptors to initiate the adaptive counter-regulatory responses to restore the normoglycaemic condition.
ABSTRACT
The carotid body chemoreceptors (CBC) play an important role in the adaptive counter-regulatory response to hypoglycaemia by evoking the CBC-mediated sympathetic neuronal system to restore normoglycaemia. Ex vivo studies have shown varied responses of insulin-induced hypoglycaemia on CBC function, and several in vivo studies have indirectly established the role of CBCs in restoring normoglycaemia in both animals and humans. However, a direct effect of insulin and/or insulin-induced hypoglycaemia on CBC activity is not established in animal models. Therefore, the aim of this study was to evaluate in vivo effects of insulin and insulin-induced hypoglycaemia on CBC activity and cardiorespiration in a preclinical large animal model. The carotid sinus nerve (CSN) activity and cardiorespiratory responses to sodium cyanide (NaCN; 25 µg/kg) were compared before (euglycaemic) and after (hypoglycaemic) intracarotid administration of insulin (12.5-100 µU/dogs) in beagle dogs. Insulin administration increased CSN activity and minute ventilation ( ) with significant (P < 0.0001) effects on heart rate and blood pressure. Insulin-mediated effects on CSN and cardiorespiration were sustained and the change in was driven by tidal volume only. Insulin significantly (P < 0.0001) lowered blood glucose level. NaCN-mediated CSN activity and were significantly (P < 0.0001) augmented during insulin-induced hypoglycaemia. The augmented was primarily driven by respiratory frequency and partially by tidal volume. The cardiovascular reflex response mediated through CBC stimulation was significantly (P < 0.0001) exacerbated during insulin-induced hypoglycaemia. Collectively, these results demonstrate direct effects of insulin and insulin-induced hypoglycaemia on CBC chemosensitivity to potentiate CBC-mediated neuroregulatory pathways to initiate adaptive neuroendocrine and cardiorespiratory counter-regulatory responses to restore normoglycaemia.
Topics: Humans; Dogs; Animals; Carotid Body; Insulin; Chemoreceptor Cells; Hypoglycemia; Reflex; Blood Pressure
PubMed: 36459572
DOI: 10.1113/EP090584 -
BioRxiv : the Preprint Server For... May 2024Autofluorescence lifetime imaging microscopy (FLIM) is sensitive to metabolic changes in single cells based on changes in the protein-binding activities of the metabolic...
Autofluorescence lifetime imaging microscopy (FLIM) is sensitive to metabolic changes in single cells based on changes in the protein-binding activities of the metabolic co-enzymes NAD(P)H. However, FLIM typically relies on time-correlated single-photon counting (TCSPC) detection electronics on laser-scanning microscopes, which are expensive, low-throughput, and require substantial post-processing time for cell segmentation and analysis. Here, we present a fluorescence lifetime-sensitive flow cytometer that offers the same TCSPC temporal resolution in a flow geometry, with low-cost single-photon excitation sources, a throughput of tens of cells per second, and real-time single-cell analysis. The system uses a 375nm picosecond-pulsed diode laser operating at 50MHz, alkali photomultiplier tubes, an FPGA-based time tagger, and can provide real-time phasor-based classification ( ., gating) of flowing cells. A CMOS camera produces simultaneous brightfield images using far-red illumination. A second PMT provides two-color analysis. Cells are injected into the microfluidic channel using a syringe pump at 2-5 mm/s with nearly 5ms integration time per cell, resulting in a light dose of 2.65 J/cm that is well below damage thresholds (25 J/cm at 375 nm). Our results show that cells remain viable after measurement, and the system is sensitive to autofluorescence lifetime changes in Jurkat T cells with metabolic perturbation (sodium cyanide), quiescent vs. activated (CD3/CD28/CD2) primary human T cells, and quiescent vs. activated primary adult mouse neural stem cells, consistent with prior studies using multiphoton FLIM. This TCSPC-based autofluorescence lifetime flow cytometer provides a valuable label-free method for real-time analysis of single-cell function and metabolism with higher throughput than laser-scanning microscopy systems.
PubMed: 38798331
DOI: 10.1101/2024.05.15.594394 -
Analytical Sciences : the International... May 2019We demonstrated a simple and rapid deacetylation reaction of p-nitrophenyl thioacetate by cyanide ion. This reaction is caused by the strong nucleophilic tendency of the...
We demonstrated a simple and rapid deacetylation reaction of p-nitrophenyl thioacetate by cyanide ion. This reaction is caused by the strong nucleophilic tendency of the cyanide ion to the electrophilic substrate and has been previously reported as the most common method for detecting cyanide ions. Tetrabutylammonium cyanide and sodium cyanide can be used as sources of cyanide ions for catalytic deacetylation reactions. Both catalysts showed almost the same catalytic reaction and the catalytic reaction was instantaneous at room temperature with a minimum concentration of cyanide ions of up to 1.0 μM. Cyanide did not catalyze the deacetylation reaction of p-nitropnenyl acetate due to a decrease in the nucleofugality of the leaving group and a decrease in the electrophilicity of carbonyl carbon in the substrate. However, the only disadvantage of this reaction system is the interference with other anions, such as acetate and azide, which also have nucleophilicity toward an electrophilic substrate. If these problems are improved, the system could be applied as a very efficient cyanide ion sensor.
PubMed: 30662014
DOI: 10.2116/analsci.18N024