Ubiquity of arsenobetaine in marine animals and degradation of arsenobetaine by sedimentary micro‐organisms

Abstract

Arsenic compounds were extracted with chloroform/methanol/water from tissues of marine animals (four carnivores, five herbivores, five plankton feeders). The extracts were purified by cation and anion exchange chromatography. Arseno-,AsO] and arsenite, arsenate, and methylarsonic acid [(CH,AsO(OH),] as a group with the same retention time were identified by high-pressure liquid chromatography. Arsenic was determined in the collected fractions by graphite furnace atomic absorption spectrometry. Arsenobetaine found in all the animals was almost always the most abundant arsenic compound in the extracts. These results show that arsenobetaine is present in marine animals independently of their feeding habits and trophic levels.Arsenobetaine-containing growth media (ZoBell 22163; solution of inorganic salts) were mixed with coastal marine sediments as the source of microorganisms. Arsenobetaine was converted in both media to trimethylarsine oxide and trimethylarsine oxide was converted to arsenite, arsenate or methylarsonic acid but not to dimethylarsinic acid. The conversion rates in the inorganic medium were faster than in the ZoBell medium. Two dominant bacterial strains isolated from the inorganic medium and identified as members of the Vibro-Aeromonas group were incapable of degrading arsenobetaine.

Formation of toxic arsenical in roasted muscles of marine animals

“…The elucidation of the forms and safety of the conversion product(s) with cooking arising from arsenicals in marine organisms should follow the striking advances so far on the study of forms [8][9][10][11][12] and safety [13][14][15] of highly accumulated arsenicals in marine organisms. Especially for arsenobetaine as the major arsenical accumulated in animals and for arsenosugars as the major ones in algae, this elucidation is essential.…”

“…To the residue in the digestion beaker were added 1.0 cm 3 of 25% diammonium hydrogen citrate, 2.0 cm 3 of 37% hydrochloric acid, 0.2 cm 3 of 1 mol dm À3 potassium iodide and 0.2 cm 3 of 0.4 mol dm À3 stannous chloride; this was diluted with water to a volume of 10 cm 3 to give an arsenic concentration of 10-80 mg dm À3 , which was determined by arsine (AsH 3 ) evolution-electrothermal atomic absorption spectrometry (Nippon Jarrel Ash, model AA 845). 8 The detection limit for arsenic was 1 ng.…”

“…7 In other words, arsenobetaine is present in marine animals independently of their feeding habits and trophic levels. 8 The isolation of arsenobetaine led to further studies that detected arsenocholine (CH 3 ) 3 As CH 2 CH 2 OH and the tetramethylarsonium ion (CH 3 ) 4 As in various animals, and arsenosugars in various algae and phytoplankton. [9][10][11][12][13] The toxicities of ubiquitous arsenobetaine in marine animals and arsenosugars in algae or phytoplankton are reported to be considerably lower than inorganic arsenicals.…”

Arsenocholine- and dimethylated arsenic- containing lipids in starspotted shark Mustelus manazo

“…13 For the dried chloroform fraction, an aliquot of each fraction was saponified (100°C, 10 min) with 12.5 times its volume of 2.4 mol dm À3 ethanolic potassium hydroxide before the digestion.…”

The Behavior of Trivalent and Pentavalent Methylarsenicals in Lake Biwa

“…34 Experimental studies in vitro demonstrated that arsenobetaine contained in organisms degraded to inorganic forms via methylarsenical intermediates. 35,36 A significant increase in inorganic arsenic was correlated with the dissolution of manganese and iron on the surface of sediment (Fig. 5).…”