Marine mollusc predator-escape behaviour altered by near-future carbon dioxide levels

Ocean acidification poses a range of threats to marine invertebrates; however, the potential effects of rising carbon dioxide (CO₂) on marine invertebrate behaviour are largely unknown. Marine gastropod conch snails have a modified foot and operculum allowing them to leap backwards rapidly when faced with a predator, such as a venomous cone shell. Here, we show that projected near-future seawater CO₂ levels (961 µatm) impair this escape behaviour during a predator–prey interaction. Elevated-CO₂ halved the number of snails that jumped from the predator, increased their latency to jump and altered their escape trajectory. Physical ability to jump was not affected by elevated-CO₂ indicating instead that decision-making was impaired. Antipredator behaviour was fully restored by treatment with gabazine, a GABA antagonist of some invertebrate nervous systems, indicating potential interference of neurotransmitter receptor function by elevated-CO₂, as previously observed in marine fishes. Altered behaviour of marine invertebrates at projected future CO₂ levels could have potentially far-reaching implications for marine ecosystems.     

Effect of ethanol on cholesterol and bile acid metabolism

Ethanol feeding increased significantly levels of hepatic esterified cholesterol and serum free and esterified cholesterol in rats. Incorporation of intraperitoneally administered [(14)C]acetate into cholesterol was significantly increased. Labeling of cholesterol was also enhanced in liver slices from animals pretreated with ethanol and incubated with [(14)C]-acetate. Ethanol consumption prolonged the half-excretion time of labeled cholic or chenodeoxycholic acids, increased slightly the pool size, and decreased daily excretion. By contrast, supplementation of the diet with cholesterol shortened the half-excretion time, did not modify pool size, and increased daily excretion. When ethanol and cholesterol feeding were combined, the effects of ethanol prevailed and there was suppression of the adaptive changes in bile acid metabolism induced by cholesterol feeding. There was also a greater accumulation of esterified cholesterol in the liver than that produced by cholesterol alone, ethanol administration alone, or the summation of both effects. Thus, cholesterol accumulation produced by ethanol feeding is associated with both enhanced cholesterogenesis and decreased bile acid excretion. Both mechanisms may play a role, but the latter is probably predominant in these studies in which cholesterol accumulation was markedly enhanced by the addition of cholesterol to the ethanol-containing diet.     

Activity of 2-Acetylaminofluorene as a UDS inducting agent in B6C3F1 mouse hepatocytes in vitro

Summary 2-Acetylaminofluorene (2AAF) is shown to be reproducibly active in inducing UDS in cultured hepatocytes from a B₆C₃F₁ mouse liver.Abbreviations 2AAF 2-acetylaminofluorene - 6BT 6-dimethylaminophenylazobenzthiazole     

Degradation of veratryl alcohol by Penicillium simplicissimum

Summary Several bacteria, yeast and fungi selectively isolated from paper-mill waste-water grew on veratryl alcohol, a key intermediate of lignin metabolism. Penicillium simplicissimum oxidized veratryl alcohol via a NAD(P)⁺-dependent veratryl alcohol dehydrogenase to veratraldehyde, which was further oxidized to veratric acid in a NAD(P)⁺-dependent reaction. Veratric-acid-grown cells contained NAD(P)H-dependent O-demethylase activity for veratrate, vanillate and isovanillate. Protocatechuate was cleaved by a protocatechuate 3,4-dioxygenase. Offprint requests to: E. de Jong