The IAEA handbook on radionuclide transfer to wildlife.

An IAEA handbook presenting transfer parameter values for wildlife has recently been produced. Concentration ratios (CRwo-media) between the whole organism (fresh weight) and either soil (dry weight) or water were collated for a range of wildlife groups (classified taxonomically and by feeding strategy) in terrestrial, freshwater, marine and brackish generic ecosystems. The data have been compiled in an on line database, which will continue to be updated in the future providing the basis for subsequent revision of the Wildlife TRS values. An overview of the compilation and analysis, and discussion of the extent and limitations of the data is presented. Example comparisons of the CRwo-media values are given for polonium across all wildlife groups and ecosystems and for molluscs for all radionuclides. The CRwo-media values have also been compared with those currently used in the ERICA Tool which represented the most complete published database for wildlife transfer values prior to this work. The use of CRwo-media values is a pragmatic approach to predicting radionuclide activity concentrations in wildlife and is similar to that used for screening assessments for the human food chain. The CRwo-media values are most suitable for a screening application where there are several conservative assumptions built into the models which will, to varying extents, compensate for the variable data quality and quantity, and associated uncertainty.

Responses of tabanids to Nzi traps baited with octenol, cow urine and phenols in Canada.

Cow urine and the two phenols responsible for the attraction of biting flies to cow urine (4-methylphenol, 3-n-propylphenol) were compared with octenol (1-octen-3-ol) as baits for Tabanidae. Relative to an unbaited Nzi trap, catches of the horseflies Hybomitra lasiophthalma (Macquart), Tabanus similis Macquart and Tabanus quinquevittatus Wiedemann (Diptera: Tabanidae) were increased by 1.5-2.6, 1.4-2.0 and 1.4-1.9 times, respectively, whenever a bait included octenol released at either 0.13 mg/h or 1.5 mg/h, regardless of the presence of phenols or urine. Catches were not affected when traps were baited with phenols alone at evaporation rates of 0.38 mg/h (4-methylphenol) and 0.022 mg/h (3-n-propylphenol). Catches of Hybomitra horseflies were increased by 1.5-1.9 times with cow urine and 2.6 times with cow urine + octenol. This bait combination could prove to be particularly useful for Hybomitra horseflies, the common tabanids of northern environments.

The feeding stimulus in Rhodnius prolixus is transmitted to the brain by a humoral factor

Neurosecretory cells in the brain of Rhodnius prolixus are known to be the source of an ovulation hormone released at feeding. They were selected to test the hypothesis that feeding brings about the release of another hormone in the abdomen which is transported forward to activate the neuroendocrine axis in the brain, and that severing the aorta interferes with this transport. These cells have previously been shown to exhibit an increase in action potential frequency at the time of release of their hormone. In normal females, the spike frequency of the cells increased after feeding and remained high over at least the next 24 h. In females with the dorsal vessel severed, the spike frequency remained low, at levels near those of unfed females, except for a transitory increase 4 h after feeding. The spike frequency of the neurosecretory cells in females with the dorsal vessel severed increased when hemolymph from fed normal females or from those with their dorsal vessel severed was placed directly on the brains of the test females. Hemolymph taken from unfed females did not produce this response. The activity in the hemolymph was heat-stable and disappeared after pronase or trypsin digestion. Similar activity was present in the fused thoracico-abdominal ganglionic mass, but absent from fore-, mid- and hindgut and from the abdominal neurosecretory organs.

Evidence for phosphatidylcholine hydrolysis by phospholipase C in rat platelets.

Production of [3H]1,2-dipalmitoylglycerol ([3H]DAG) from 1-palmitoyl-2-[9,10-3H]palmitoyl-sn-glycero-3-phosphocholine and [3H]phosphorylcholine from 1,2-dipalmitoyl-sn-glycero-3-[Me-3H]phosphocholine was studied using sonicated rat platelets. The formation of [3H]DAG and [3H]phosphorylcholine occurred at a comparable rate. [3H]Phosphorylcholine formation was dependent on the concentration of the substrate, platelet sonicates and calcium in the incubation medium. The [3H]phosphorylcholine formation increased in presence of 0.01% deoxycholate and 0.01% Triton X-100. The phosphatidylcholine-phospholipase C (PC-PLC) in the platelet sonicates was recovered in both the supernatant and particulate fractions obtained after ultracentrifugation at 105,000 x g for 1 h. The PC-PLC activity in both fractions was inhibited by 2 mM EDTA. In the presence of 0.01% deoxycholate and 0.01% Triton X-100 the activity in the particulate fraction increased compared to the activity in the supernatant, which was inhibited by 0.01% Triton X-100. The pH optima for PC-PLC in both fractions was between pH 7.2 and 7.6. PC-PLC activity was also found in rabbit and human platelet sonicates, but the activity was significantly lower than in rat platelet sonicates. There was no evidence to suggest presence of phosphatidylcholine-specific phospholipase D activity in rat sonicated platelets. This data, therefore, provides direct evidence for the presence of PC-PLC activity in rat platelets.