An investigation on the Culicoides species composition at seven sites in southern Switzerland

In the past decade, there have been regular outbreaks of bluetongue (BT) in many parts of Europe. Owing to the presence of BT disease and its vectors in countries adjacent to Switzerland, an initial entomological survey was conducted in 2003, which established the presence of several midges of the genus Culicoides (Diptera: Ceratopogonidae). Subsequently, a sentinel herd monitoring system was established with the primary entomological aim being the determination and further study of Culicoides population compositions. Insects were collected in 2005 and 2006 at seven sentinel herd sites in the south of Switzerland (canton of Ticino) near the border of Italy, using Onderstepoort-type light traps. This region is botanically and zoologically similar to the Mediterranean and is one of the warmest and most humid areas of the country, hence it is considered a potential access path for BT disease into Switzerland. Collections were made at four cattle farms, two equestrian centres and one goat farm. Sites were sampled four times per month from June to October. Traps were operated from dusk until dawn and samples were collected monthly for analysis through microscopy as well as a Culicoides imicola -specific PCR. Results confirmed the absence of C. imicola (Kieffer) and demonstrated that the potential BT virus vectors are highly abundant, notably: Culicoides obsoletus (Meigen), Culicoides scoticus (Downes & Kettle) and Culicoides dewulfi (Goetghebuer) subgenus Avaritia and Culicoides pulicaris (Linnaeus) subgenus Culicoides . These findings expand the current knowledge of Culicoides population composition in the southern part of the Switzerland. Culicoides cataneii (Clastrier), Culicoides flavipulicaris (Dzhafarov), Culicoides indistinctus (Khalaf), Culicoides nubeculosus (Meigen) and species of the Grisescens complex were reported for the first time in Switzerland.     

Halogenated phloroglucinols from Rhabdonia verticillata

Six bromo- and/or chloro- derivatives of phloroglucinol have been obtained from the red alga Rhabdonia verticillata.     

Microradioisotopic assay for indoleamine N-methyltransferase and analysis of products by liquid chromatography

A rapid method for the separation of tryptamine, 5-hydroxytryptamine, and their N-methylated derivatives is described. The method involves liquid chromatography using a cation exchange column with the eluant monitored either by ultraviolet or fluorescence spectroscopy. The latter technique permits the detection of picogram quantities of indoleamines. Using normal-phase liquid chromatography a complete separation of tryptamine, its N-methylated derivatives, and their β-carboline analogs was also achieved. A radioisotopic assay with the potential to detect indoleamine N-methyltransferase activity in milligram quantities of rabbit lung tissue was developed. The radioisotopically labeled products formed from a number of substrates in such assays were characterized by liquid chromatography.     

Impaired down-regulation of pituitary dopamine receptors by estradiol in aged rats

Administration of 17 beta-estradiol to mature (6-12 months) rats results in a more than 50% reduction in pituitary dopamine receptor concentrations, without affecting binding affinity. In contrast, when the same manipulation is performed on senescent (24-25 months) rats, negligible change in receptor concentration occurs. These results suggest that age-related increases in estrogen-stimulated prolactin release are not due to decreased dopaminergic inhibition at the receptor level.