Copper Accumulation in the Digestive Caecae of Limnoria quadripunctata Holthius (Isopoda: Crustacea) Tunnelling CCA-Treated Wood in Laboratory Cultures

Summary To investigate the mechanisms by which the isopod Limnoria tolerates copper, chromium and arsenic when tunnelling CCA-treated wood in the marine environment, digestive caecae of specimens of L. quadripunctata from CCA-treated and untreated Pinus sylvestris sapwood were examined using transmission electron microscopy (TEM) and energy dispersive X-ray detection (EDX). Copper-containing granules were found to be present in the small cells of the digestive caecae (midgut) of Limnoria from both treated and untreated wood. However, individuals tunnelling treated timber contained a greater number of granules, with six types of morphology being distinguished of which only two were present in Limnoria from untreated wood. The presence of copper-containing granules in Limnoria from untreated timber may be explained by the ability of this isopod to acquire and store copper from seawater for use in enzymes and blood pigments. The increased number of copper granules in individuals tunnelling treated wood was believed to result from elevated levels of this element in the food substrate. This ability to store copper allows these organisms to tolerate this metal in the wood substrate and may explain how this organism is able to attack CCA-treated wood in service. No chromium, or arsenic, was detected in the digestive caecal cells.

Quantitative Measurement of Blood Pigments in Cerebrospinal Fluid by Derivative Spectrophotometry

A spectrophotometric method for the simultaneous calculation of the concentrations of oxyhaemoglobin, methaemoglobin and bilirubin in cerebrospinal fluid is described, based on the first and second derivative spectrum between 350 and 650 nm. Specificity compares favourably with other methods currently in use. The proposed method minimises the effect of turbidity and permits the measurement of concentrations below 0–3 μmol/L.

Quantification of desferrioxamine in blood plasma by inductively coupled plasma atomic emission spectrometry.

A sensitive method, inductively coupled plasma atomic emission spectroscopy, is used to measure desferrioxamine in blood plasma. The desferrioxamine is transformed into its iron chelate, ferrioxamine, which is extracted into benzyl alcohol, then re-extracted into HCl (0.5 mol/L), which is used as the sample for the spectroscopy. For a 0.5-mL plasma sample, the detection limit (1 microgram/mL) suffices for following the concentration of desferrioxamine in plasma after its subcutaneous or intramuscular injection (40 mg per kg of body weight). Neither blood pigments nor trace metals interfere.

Preparation of whole blood for liquid scintillation counting.

Liquid scintillation counting of 3H-labeled whole-blood samples is severely impaired owing to quenching by blood pigments. In this study, dry oxidation and chemical solubilization followed by decolorization were the two general methods used to eliminate color quenching. Three blood volumes were examined: 0.25, 0.50, and 1.0 mL. Dry oxidation yielded complete recoveries of 3H label with counting efficiencies greater than 30% for up to 1.0 mL of blood. Although blood volumes larger than 0.25 mL can be used with chemical solubilization and decolorization, treatment of 0.25 mL of blood gave the highest counting efficiencies, with count rates comparable to those for 1.0-mL samples.