Biorecovery of gold.

Recovery of ionic and metallic gold (Au) from a wide variety of solutions by selected species of bacteria, yeasts, fungi, algae, and higher plants is documented. Gold accumulations were up to 7.0 g/kg dry weight (DW) in various species of bacteria, 25.0 g/kg DW in freshwater algae, 84.0 g/kg DW in peat, and 100.0 g/kg DW in dried fungus mixed with keratinous material. Mechanisms of accumulation include oxidation, dissolution, reduction, leaching, and sorption. Uptake patterns are significantly modified by the physicochemical milieu. Crab exoskeletons accumulate up to 4.9 g Au/kg DW; however, gold accumulations in various tissues of living teleosts, decapod crustaceans, and bivalve molluscs are negligible.

Effects of serotonin and fluoxetine on blood glucose regulation in two decapod species

One of the best known crustacean hormones is the crustacean hyperglycemic hormone (CHH). However, the mechanisms involved in hormone release in these animals are poorly understood, and thus constitute the central objective of the present study. Different groups of crustaceans belonging to diverse taxa (Chasmagnathus granulata, a grapsid crab and Orconectes limosus, an astacid) were injected with serotonin, fluoxetine, or a mixture of both, and glycemic values (C. granulata and O. limosus) and CHH levels (O. limosus) were determined after 2 h in either submerged animals or animals exposed to atmospheric air. Both serotonin and fluoxetine caused significant hyperglycemia (P<0.05) after injection into the blood sinus of the two species, an effect enhanced after exposure to atmospheric air. In C. granulata blood glucose increased from 6.1 to 43.3 and 11.4 mg/100 ml in submerged animals and from 5.7 to 55.2 and 22.5 mg/100 ml in air-exposed animals after treatment with serotonin and fluoxetine, respectively. In O. limosus the increases were from 1.2 to 59.7 and 135.2 mg/100 ml in submerged animals and from 2.5 to 200.3 and 193.6 mg/100 ml in air-exposed animals after treatment with serotonin and fluoxetine, respectively. Serotonin and fluoxetine also caused a significant increase in the circulating levels of CHH in O. limosus, from 11.9 to 43 and 45.7 fmol/ml in submerged animals and from 13.2 to 32.6 and 45.7 fmol/ml in air-exposed animals, respectively, thus confirming their action as neuroregulators in these invertebrates

Effects of crustacean hyperglycemic hormones from Carcinus maenas and Orconectes limosus on blood and muscle glucose and glycogen concentration of Chasmagnathus granulata

The effects of purified crustacean hyperglycemic hormones (CHH) from Carcinus maenas or Orconectes limosus, and of eyestalk extract of Chasmagnathus granulata on the blood and muscle glucose and glycogen concentration of Chasmagnathus granulata were investigated. Different groups of animals (at least 7 animals per group) were injected with CHH from either C. maenas or O. limosus CHH dissolved in saline (16 pmol/animal) or crude eyestalk extract of C. granulata (1 eyestalk equivalent/animal). All injections had a volume of 10 microliters. Blood and muscle glucose and glycogen concentrations were determined immediately before the injections and after 30, 60 and 120 min. CHH administration from both species, as well as eyestalk extract, resulted in marked hyperglycemia. However, their effects were different. CHH from C. maenas also caused a decrease in the glycogen concentration of blood (from 89.8 +/- 4.3 to 76.6 +/- 3.1 mg/100 ml) and muscle (from 7.9 +/- 0.8 to 4.0 +/- 0.7 mg/g) and glucose concentration of muscle (from 2.4 +/- 0.3 to 1.2 +/- 0.2 mg/g). CHH from O. limosus caused an increase of glycogen concentration of muscle (from 4.9 +/- 1.1 to 9.0 +/- 1.1 mg/g). The injection of eyestalk extract resulted also in a decrease of hemolymph glycogen (from 157.7 +/- 20.6 to 30.2 +/- 7.7 mg/100 ml). Therefore, C. granulata may have different receptors for CHH in its different tissues, and/or in the same tissue, which act through different metabolic pathways to achieve the same final result, i.e., hyperglycemia

The hemolymph of chasmagnathus granulata dana,1851 (Decapoda - grapsidae) as a target tissue ofthe crustacean hyperglycemic hormone

The effect of crustacean hyperglycemic hormone (CHH) was investigated on the hemolymph of Chasmagnathus granulata, a meso-supralitoral crab from southern Brazil. Serum glucose increased significantly (P®0.05) after incubation of total hemolymph in the presence of the eyestalk extract of a member of the same species. Also glucose uptake from blood serum, not affected by eyestalk extract (P¼0.05) was observed after incubation of total hemolymph in the presence of glucose.The results that the hemolymph may be a target tissue of CHH and that this hormone may act by mobilizing carbohydrate reserves possibly from hematocytes.