Immunotoxicity of Organic Arsenic Compounds in Marine Animals

In the present study, we demonstrated for the first time the immunotoxic effects of organic arsenic compounds in marine animals, namely arsenocholine [AsCho; trimethyl(2-hydroxyethyl)arsonium cation], arsenobetaine [AsBe; the trimethyl(carboxymethyl)arsonium zwitterion] and the tetramethylarsonium ion (TetMA), to murine principal immune effector cells (macrophages and lymphocytes), comparing them with the effects of inorganic arsenicals in vitro . Inorganic arsenicals (arsenite and arsenate) showed strong cytotoxicity to both macrophages and lymphocytes. The concentration of arsenite that reduced the number of surviving cells to 50% of that in untreated controls (IC₅₀) was 3–5 μmol dm⁻³, and the cytotoxicity of arsenate (IC₅₀=100 μ-1 m mol dm⁻³) was lower than that of arsenite. Compared with these findings, trimethylarsenic compounds in marine animals, AsCho and AsBe, were less toxic even at a concentration over 10 mmol dm⁻³ to both macrophages and lymphocytes; however, TetMA had weak, but significant, cytotoxicity to these cells (IC₅₀ was about 6 mmol dm⁻³).     

Arsenic Compounds in Terrestrial Organisms I: Collybia maculata,Collybia butyracea and Amanita muscaria from Arsenic Smelter Sites in Austria

Three mushroom species from two old arsenic smelter sites in Austria were analyzed for arsenic compounds. The total arsenic concentrations were determined by ICP–MS. Collybia maculata contained 30.0 mg, Collybia butyracea 10.9 mg and Amanita muscaria 21.9 mg As kg⁻¹ dry mass. The arsenic compounds extracted with methanol/water (9:1) from the dried mushroom powders were separated by HPLC on anion-exchange and reversed-phase columns and detected by ICP-MS using a hydraulic high-pressure nebulizer. In Collybia maculata almost all arsenic is present as arsenobetaine. Collybia butyracea contained mainly arsenobetaine (8.8 mg As kg⁻¹ dry mass) and dimethylarsinic acid (1.9 mg As kg⁻¹). Amanita muscaria contained arsenobetaine (15.1 mg As kg⁻¹), traces of arsenite, dimethylarsinic acid and arsenate, and surprisingly arsenocholine (2.6 mg As kg⁻¹) and a tetramethylarsonium salt (0.8 mg As kg⁻¹). © 1997 by John Wiley & Sons, Ltd.     

Arsenic Compounds in Higher Fungi

In 50 mushroom species (56 samples) from Slovenia, Switzerland, Brazil, Sweden, The Netherlands and USA, total arsenic was determined by radiochemical neutron activation analysis (RNAA). Arsenic concentrations ranged from 0.1 to 30 μg g⁻¹ (dry mass). Arsenic compounds were determined in methanol extracts from the mushrooms by HPLC–ICP–MS. The aim of the study was not only to quantify arsenic compounds in mushrooms but also to uncover trends relating the methylating ability of a mushroom to its taxonomic or evolutionary status. The main arsenic compound found in many mushrooms (various puffballs, Agaricales and Aphyllophorales) was arsenobetaine. Arsenate [As(V)] was the main arsenic species in Laccaria fraterna and Entoloma rhodopolium and arsenite [As(III)] in Tricholoma sulphureum. A mixture of arsenite and arsenate was present in Amanita caesarea. Dimethylarsinic acid (DMA) and methylarsonic acid were present in many mushrooms, but generally as minor components. In Laccaria laccata, Leucocoprinus badhamii and Volvariella volvacea, DMA was the major metabolite. Arsenocholine (AC) and the tetramethylarsonium ion were present in a few species, generally at low concentrations, except for Sparassis crispa, in which AC was the main compound. Tri- methylarsine oxide was not found in any of the mushrooms. In some species small amounts of unknown compounds were also present. The possible taxonomic significance of the metabolite patterns and the predominance of arsenobetaine in more advanced fungal types are discussed. © 1997 John Wiley & Sons, Ltd.     

Arsenic Compounds in Zoo- and Phyto-plankton of Marine Origin

Major water-soluble arsenic compounds accumulated in some zoo- and phyto-plankton were identified. Zooplankton were collected at sampling stations in the Sea of Japan by a Norpac net towed from 600 m depth to the surface. Phytoplankton were cultivated under axenic conditions. Water-soluble arsenic compounds were extracted repeatedly from plankton tissues by aqueous methanol. The arsenic compounds in the extracts were analyzed by HPLC–ICP/MS. Among zooplankton analyzed in the present study, two carnivorous species, i.e. Amphipoda ( Themisto sp.) and Sagittoidea ( Sagitta sp.), contained arsenobetaine as the dominant arsenic species. Arsenobetaine was the major species in Euphausiacea ( Euphausia sp.), also. The most abundant arsenic compound in the herbivorous Copepoda species ( Calanus sp.), on the other hand, was an arsenic-containing ribofuranoside with a sulfate ester group, and arsenobetaine was only a minor component. Phytoplankton contained arsenic-containing ribofuranosides apparently in a species-speific manner. The arsenic compounds in zooplankton seem to reflect their feeding habit; i.e. carnivorous species eating zooplankton or other small animals accumulate arsenobetaine, while herbivorous ones eating phytoplankton accumulate arsenic-containing ribofuranosides as major arsenic compounds.     

Arsenic Compounds Accumulated in Sedimentary Microorganisms Cultivated in Media Containing Several Arsenicals

Sediments, as sources of microorganisms, were added to two kinds of media, 1/5 ZoBell 2216E and a solution of inorganic salts, which contained inorganic arsenic(III), inorganic arsenic(V), methanearsonic acid, dimethyl- arsinic acid, trimethylarsine oxide, tetramethylarsonium salt or arsenocholine. After 17 days of incubation at 20 °C, the arsenicals that had accumulated in the microorganisms were analysed by high-performance liquid chromatography (HPLC). While the more toxic arsenicals [inorganic arsenic(III), inorganic arsenic(V), methanearsonic acid, dimethylarsinic acid] were not converted in the microorganisms, trimethylarsine oxide and tetramethylarsonium salt were considerably degraded to inorganic arsenic(V), and arsenocholine to arsenobetaine. Arsenobetaine that had accumulated in the microorganisms was extracted and confirmed by thin-layer chromatography (TLC) and fast atom bombardment (FAB) mass spectrometry.     

Arsenic Compounds in Terrestrial Organisms II: Arsenocholine in the Mushroom Amanita muscaria

Arsenic compounds were identified and quantified in the mushroom Amanita muscaria, collected close to a facility that had roasted arsenic ores. The powdered dried mushrooms were extracted with methanol/water (9:1), the extracts were concentrated and the concentrates were dissolved in water. The resulting solutions were chromatographed on anion-exchange, cation-exchange and reversed- phase columns. Arsenic was detected on-line with an ICP–MS detector equipped with a hydraulic high-pressure nebulizer. Arsenite, arsenate, dimethylarsinic acid and the tetramethylarsonium cation were minor arsenic compounds (∼2% each of the total 22 mg kg⁻¹ dry mass), and arsenobetaine, arsenocholine (∼15% each) and several unidentified arsenic compounds (∼60%) were the major arsenic compounds in Amanita muscaria. The presence of arsenocholine (detected for the first time in a terrestrial sample) was ascertained by matching retention times in the anion-exchange, cation- exchange and reversed-phase chromatograms with the retention time of synthetic arsenocholine bromide and chromatographing extracts spiked with arsenocholine bromide. © 1997 John Wiley & Sons, Ltd.     

Arsenic speciation in clams of British Columbia

The water-soluble arsenic compounds in five species of clams – Butter clam (Saxidomus giganteus), Horse clam (Schizothoerus nuttalli), Soft-shelled clam (Mya arenaria), Native littleneck clam (Protothaca staminea), and Manila clam (Venerupis japonica) – are described. Varying amounts of arsenobetaine and tetramethylarsonium ion are the major arsenicals found in all species. Butter clams show the presence of a third compound which appears to be trimethylarsine oxide. Small amounts of as-yet-unidentified arsenicals can also be isolated.     

The chemical form and acute toxicity of arsenic compounds in marine organisms

A method for the separation and identification of inorganic and methylated arsenic compounds in marine organisms was constructed by using a hydride generation/cold trap/gas chromatography mass spectrometry (HG/CT/GC MS) measurement system. The chemical form of arsenic compounds in marine organisms was examined by the HG/CT/GC MS system after alkaline digestion. It was observed that trimethylarsenic compounds were distributed mainly in the water-soluble fraction of muscle of carnivorous gastropods, crustaceans and fish. Also, dimethylated arsenic compounds were distributed in the water-soluble fraction of Phaeophyceae. It is thought that most of the trimethylated arsenic is likely to be arsenobetaine since this compound released trimethylarsine by alkaline digestion and subsequent reduction with sodium borohydride. The major arsenic compound isolated from the water-soluble fraction in the muscle and liver of sharks was identified as arsenobetaine from IR, FAB Ms data, NMR spectra and TLC behaviour. The acute toxicity of arsenobetaine was studied in male mice. The LD₅₀ value was higher than 10 g kg⁻¹. This compound was found in urine in the non-metabolized form. No particular toxic symptoms were observed following administration. These results suggest that arsenobetaine has low toxicity and is not metabolized in mice. The LD₅₀ values of other minor arsenicals in marine organisms, trimethylarsine oxide, arsenocholine and tetramethylarsonium salt, were also examined in mice.     

Adsorption of Inorganic and Organic Arsenic Compounds by Aluminium-loaded Coral Limestone

Coral limestones were treated with an aqueous solution of aluminium sulfate and thereby aluminium-loaded coral limestones (Al-CL) were prepared. By use of Al-CL as an adsorbent, the adsorption of inorganic arsenic compounds (arsenate [As(V)] and arsenite [As(III)] and of organic arsenic compounds (methylarsonic acid, dimethylarsinic acid, and arsenobetaine) was examined. The adsorption ability of Al-CL is superior to that of iron(III)-loaded coral limestone (Fe-CL) for As(V), As(III), methylarsonic acid and dimethylarsinic acid. The adsorption of As(V) and As(III) is almost independent of the initial pH over a wide range (2 or 3 to 11). The addition of other anions, such as chloride, nitrate, sulfate and acetate, in the solution does not affect the adsorption of As(V) and As(III), whereas the addition of phosphate greatly interferes with the adsorption. Arsenic adsorption is effectively applied to a column-type operation and the adsorption capability for As(V) is 150 μg/g coral limestone.     

Cytotoxicological aspects of organic arsenic compounds contained in marine products using the mammalian cell culture technique

Arsenobetaine, arsenocholine, trimethylarsine oxide and tetramethylarsonium iodide, which are contained in marine fishery products, were examined for their potencies on cell growth inhibition, chromosomal aberration and sister chromatid exchange (SCE). Arseno- betaine, the major water-soluble organic arsenic compound in marine animals, exhibited very low cytotoxicity towards mammalian cells. This compound showed no cell growth inhibition at a concentration of 10 mg cm⁻³ and the cytotoxicity was lower than 1/14 000th of that of sodium arsenite and 1/1600th of that of sodium arsenate towards BALB/c 3T3 cells. The chromosomal aberrations caused by arsenobetaine at a concentration of 10 mg cm⁻³ consisted mainly of chromatid gaps and chromatid breaks, but in this concentration chromosomal breakage owing to its osmotic pressure is likely to be considerable. No SCE was observed at a concentration of 1 mg cm⁻³. Arsenocholine and trimethylarsine oxide also showed no cell growth inhibited at a concentration of 10 mg cm⁻³. However, tetramethylarsonium iodide inhibition the growth of BALB/c 3T3 at a concentration of 8 mg cm⁻³. These compounds exhibited a low ability to induce chromosomal aberrations at a concentration range of 2–10 mg cm⁻³ and no SCE was observed at a concentration of 1.0 mg cm⁻³. These results suggested that the major and minor organic arsenic compounds contained in marine fishery products are much less cytotoxic inorganic arsenic, methylarsonic acid and dimethylarsinic acid. © 1998 John Wiley & Sons, Ltd.     

Arsenic species in terrestrial fungi and lichens from Yellowknife,NWT, Canada

Levels of total arsenic and arsenic species were determined in fungi collected from Yellowknife, NWT, Canada, an area that has been affected by past mining activities and elevated arsenic levels. Lichens (belonging to Cladonia and Cladina genera), as well as the mushrooms Coprinus comatus, Paxillus involutus, Psathyrella candolleana and Leccinum scabrum, were studied for the first time. Most of the fungi contained elevated arsenic levels with respect to data found in the literature for background levels. Minor amounts of arsenobetaine were found in all lichen samples. The major water‐soluble arsenic species in the fungi were inorganic arsenic for lichens and Psathyrella candolleana, arsenobetaine for Lycoperdon pyriforme and Coprinus comatus, and dimethylarsenate for Paxillus involutus and Leccinum scabrum. A large proportion of water‐soluble arsenic in Paxillus involutus occurred as an unknown compound, which did not co‐chromatograph with any of the available standard arsenic compounds. Low proportions of water‐soluble arsenic species (made evident by low extraction efficiencies) were observed in the majority of fungi studied. Arsenic that is not extracted may be bound to lipids, cell components or proteins, or might exist on the surface of the fungus as minerals. Copyright © 2000 John Wiley & Sons, Ltd.     

Metabolism of arsenic compounds by the blue mussel mytilus edulis after accumulation from seawater spiked with arsenic compounds

Blue mussels (Mytilus edulis) were exposed to 100 μg As dm^?3 in the form of arsenite, arsenate, methylarsonic acid, dimethylarsinic acid, arsenobetaine, arsenocholine, trimethylarsine oxide, tetramethylarsonium iodide or dimethyl-(2-hydroxyethyl)arsine oxide in seawater for 10 days. The seawater was renewed and spiked with the arsenic compounds daily. Analyses of water samples taken 24 h after spiking showed that arsenobetaine and arsenocholine had been converted to trimethylarsine oxide, whereas trimethylarsine oxide and tetramethylarsonium iodide were unchanged. Arsenobetaine was accumulated by mussels most efficienty, followed in efficiency by arsenocholine and tetramethylarsonium iodide. None of the other arsenic compounds was significantly accumulated by the mussels. Extraction of mussel tissues with methanol revealed that control mussels contained arsenobetaine, a dimethyl-(5-ribosyl)arsine oxide and an additional arsenic compound, possibly dimethylarsinic acid. Mussels exposed to arsenobetaine contained almost all their experimentally accumulated arsenic as arsenobetaine, and mussels exposed to tetramethylarsonium iodide contained it as the tetramethylarsonium compound. Mussels exposed to arsenocholine had arsenobetaine as the major arsenic compound and glycerylphosphorylarsenocholine as a minor arsenic compound in their tissues. The results show that arsenobetaine and arsenocholine are efficiently accumulated from seawater by blue mussels and that in both cases the accumulated arsenic is present in the tissues as arsenobetaine. Consequently arsenobetaine and/or arsenocholine present at very low concentrations in seawater may be responsible for the presence of arsenobetaine in M. edulis and probably also among other marine animals. The quantity of arsenobetaine accumulated by the mussels decreases with increasing concentrations of betaine. HPLC-ICP-MS was found to be very powerful for the investigation of the metabolism of arsenic compounds in biological systems.     

Proximate Composition,Bioactive Compounds,and Antioxidant Potential of Wild Halophytes Grown in Coastal Salt Marsh Habitats

Halophytes have been characterized as a potential resource for fiber, food, fodder, and bioactive compounds. Proximate composition, bioactive compounds, and antioxidant activity of five wild dominant halophytes (Arthrocnemum macrostachyum, Halocnemum strobilaceum, Limoniastrum monopetalum, Limoniastrum pruinosum, and Tamarix nilotica) naturally growing along the Nile Delta coast were assessed. The soil supporting these halophytes was sandy to sand-silty, alkaline, with low organic carbon, and relatively high CaCO₃. H. strobilaceum attained the highest moisture content, ash, crude fiber, lipids, and total soluble sugars. L. monopetalum showed the highest content of crude protein (18.00%), while T. nilotica had the highest content of total carbohydrates. The studied halophytes can be ranked according to their nutritive value as follows: H. strobilaceum > L. monopetalum > A. macrostachyum > L. pruinosum > T. nilotica. A. macrostachyum attained the highest amount of Na⁺, K⁺, Ca²⁺, and Mg²⁺. A. macrostachyum showed a high content of phenolic compounds, while H. strobilaceum was rich in tannins and saponin contents. The MeOH extract of A. macrostachyum and H. strobilaceum exhibited substantial antioxidant activity. The present results showed that the studied halophytes could be considered as candidates for forage production or used as green eco-friendly natural resources for bioactive compounds.     

Natural Dietary Compounds in the Treatment of Arsenic Toxicity

Chronic exposure to arsenic (As) compounds leads to its accumulation in the body, with skin lesions and cancer being the most typical outcomes. Treating As-induced diseases continues to be challenging as there is no specific, safe, and efficacious therapeutic management. Therapeutic and preventive measures available to combat As toxicity refer to chelation therapy, antioxidant therapy, and the intake of natural dietary compounds. Although chelation therapy is the most commonly used method for detoxifying As, it has several side effects resulting in various toxicities such as hepatotoxicity, neurotoxicity, and other adverse consequences. Drugs of plant origin and natural dietary compounds show efficient and progressive relief from As-mediated toxicity without any particular side effects. These natural compounds have also been found to aid the elimination of As from the body and, therefore, can be more effective than conventional therapeutic agents in ameliorating As toxicity. This review provides an overview of the recently updated knowledge on treating As poisoning through natural dietary compounds. This updated information may serve as a basis for defining novel prophylactic and therapeutic formulations.     

高效液相色谱-电感耦合等离子体质谱联用技术测定干海产品中砷化学形态

利用高效液相色谱-电感耦合等离子体质谱联用技术研究了海带、羊栖菜、紫菜及浒苔等干海产品中的砷含量及其化学形态.实验表明,干海产品中主要砷形态为3种未知砷化物,对3种未知砷化物进行了表征.采用高效液相色谱与飞行时间质谱联用技术对羊栖菜和海带中的3种未知砷化物的分子量,分别为329.0599, 483.0738和409.0162,通过对比,确定这3个未知峰分别为3种砷糖类物质: DMA-glycerol ribose, DMA-phosphate ribose和DMA-sulfate ribose.对样品中砷的定量分析结果显示,干海产品中砷总量虽然超出我国国标中关于海产品中砷限量标准规定的20倍以上,但大多数植物性干海产品中主要的砷形态为毒性较低的砷糖类物质DMA-sulfate ribose(U4),其含量约占可提取砷量的51.1%～80.3%,海带中的砷主要以DMA-phosphate ribose(U3)的形式存在,占总可提取砷的48.9%.     

Speciation of Tin,Lead, Mercury,Arsenic and Selenium Compounds by Capillary Electrophoresis

Abstract

Capillary electrophoresis (CE) methods published over the period 1992–2000 for the speciation of tin, lead, mercury, selenium and arsenic are reviewed, with emphasis on the determination of the metallorganic species. Analytical conditions and detection techniques suitable for the determination of these species are discussed. The electrolytes covered by the review include both nonmicellar and micellar solutions. Although direct UV detection is still the predominant detection method for speciation by capillary electrophoresis, ICPMS has been gaining in significance because of its sensitivity and selectivity in elemental analysis. Further, ways of increasing the concentration sensitivity are outlined and discussed. Apart from the use of more sensitive detectors, this can be accomplished either by derivatisation of the analytes to form highly absorbing or fluorescent species or thorough leading a higher total amount of the analytes into the capillary. The latter aim can be achieved by preconcentration using solid-phase extraction (SPE), or using various on-capillary stacking methods. Finally, an overview of applications to speciation analysis is presented, organized according to the particular element being determined.     

Determination of Copper in the Presence of Various Amounts of Arsenic with L‐Cysteine Modified Gold Electrodes

An L ‐cysteine modified gold electrode for the determination of copper in the presence of various amounts of arsenic with anodic stripping voltammetry has been studied. The electrode was fabricated by immersing a gold electrode in an ethanol solution of 5mM L ‐cysteine for 60 min. Various parameters, such as the effect of different supporting electrolytes, the pH of the electrolyte and the deposition potential were investigated. Under optimum conditions, copper was accumulated at ?0.3 V (vs. SEC) for 60 s in 0.1 M phosphate buffer pH 5.0 in the presence of different amounts of arsenic. Essentially the same sensitivities (0.33±0.001 μA/μM) and limits of detection (0.13±0.002 μM) of copper were obtained with various amount of arsenic in the range 2 μM to 20 μM.     

Determination of inorganic arsenic and organic arsenic compounds in marine organisms by hydride generation/cold trap/gas chromatography— mass spectrometry

The behavior of arsenite, methylarsonic acid, dimethylarsinic acid, trimethylarsine oxide, dimethyl-R-arsine oxides, and trimethyl-R-arsonium compounds (R = carboxymethyl, 2-carboxyethyl, 2-hydroxyethyl) toward sodium borohydride and hot aqueous sodium hydroxide was investigated. The arsines obtained by sodium borohydride reduction of the undigested and digested solutions were collected in a liquid-nitrogen cooled trap, separated with a gas chromatograph, and detected with a mass spectrometer in the selected-ion-monitoring mode. The investigated arsenic compounds were stable in hot 2 mol dm^?3 sodium hydroxide except arsenobetaine [trimethyl(carboxymethyl)arsonium zwitterion] that was converted to trimethylarsine oxide, and dimethyl(ribosyl)arsine oxides that were decomposed to dimethylarsinic acid. Hydride generation before and after digestion of extracts from marine organisms allowed inorganic arsenic, methylated arsenic, arsenobetaine, and ribosyl arsenic compounds to be identified and quantified. This method was applied to extracts from shellfish, fish, crustaceans, and seaweeds.     

N-Alkylation of Aniline and Its Derivatives by Alcohols in the Presence of Copper Compounds

Russian Journal of Organic Chemistry - N-Alkyl- and N,N-dialkyl-substituted anilines were obtained in the reaction of aniline and its derivatives with primary and secondary alcohols in the presence...     

Determination of Arsenic in Organic Compounds and Other Matrices by Flame Emission Spectrometry

Abstract

A direct and simple method for arsenic in organic compounds involves merely dissolution of the sample in an organic solvent, such as benzene, cyclohexane, or methyl isobutyl ketone, and direct aspiration into a fuel-rich acetylene-oxygen flame. The arsenic line at 2350 Å is used; the detection limit is 2.2 ü/ml. From iron and copper matrices arsenic is isolated by extraction from a solution 9 M in HCI and 0.25 M in KI with benzene.