Indoor and outdoor winter activity of Culicoides biting midges, vectors of bluetongue virus, in Italy.

Indoor and outdoor winter activity of Culicoides spp. (Diptera: Ceratopogonidae) in central Italy was investigated in order to evaluate whether indoor activity might account for the overwintering of bluetongue virus, as has been hypothesized by some authors. Weekly Culicoides collections were performed at three farms over three consecutive winter seasons. At each farm, two black-light traps were operated simultaneously, indoors and outdoors. Culicoides were identified using both morphological and molecular means. The Culicoides obsoletus group accounted for 98.2% of sampled specimens. Within this group, C. obsoletus s.s. accounted for 56.8% and Culicoides scoticus for 43.2% of samples. Nulliparous, parous and engorged females were caught throughout the entire winter, both indoors and outdoors. At times, indoor catch sizes outnumbered outdoor collections. A significant inverse correlation was found between minimum temperature and the proportion of indoor Culicoides of the total midge catch, thus indicating that lower outdoor temperatures drive Culicoides midges indoors. High rates of engorged females were recorded indoors, possibly as the result of the propensity of C. obsoletus females to feed indoors. Higher proportions of parous females were found in indoor than in outdoor catches, indicating higher survival rates indoors and, consequently, higher vectorial capacities of midges sheltering indoors compared with those remaining outdoors.

Fast receptor-induced formation of glycerophosphoinositol-4-phosphate, a putative novel intracellular messenger in the Ras pathway.

Glycerophosphoinositols are phosphoinositide metabolites whose levels are constitutively elevated in Ras-transformed cells. Here, we show that one of these compounds, glycerophosphoinositol-4-phosphate (GroPIns-4-P) responds acutely to the stimulation of the epidermal growth factor receptor, with a fast, massive and transient increase. The mechanism leading to GroPIns-4-P formation involves the activation of phosphoinositide-3 kinase and the small GTP-binding protein Rac, since GroPIns-4-P was neither formed in cells expressing the dominant negative form of Rac nor in cells treated with the phosphoinositide-3 kinase inhibitor wortmannin. GroPIns-4-P has been previously shown to inhibit adenylyl cyclase. Accordingly, epidermal growth factor also decreased the basal, cholera toxin-stimulated, and forskolin-stimulated cyclic AMP levels with kinetics similar to those of GroPIns-4-P formation, suggesting that GroPIns-4-P mediates this inhibitory effect. The hormone-induced formation of GroPIns-4-P was detected in several cell lines of various origin, suggesting that GroPIns-4-P is a novel intracellular messenger of the Ras pathway, possibly able to convey information from tyrosine kinase receptors to the cyclic AMP cascade.

Release of the mitogen lysophosphatidylinositol from H-Ras-transformed fibroblasts; a possible mechanism of autocrine control of cell proliferation.

Lysophosphatidylinositol (LysoPtdIns) is formed by a constitutively-active phosphoinositide-specific phospholipase A2 in Ras-transformed cells and can stimulate cell proliferation. To evaluate whether LysoPtdIns could function as an autocrine modulator of cell growth, we examined whether LysoPtdIns can be released in the medium of Ras-transformed FRT-Fibro fibroblasts and thyroid cells. Here, we report that LysoPtdIns accumulates in the extracellular space of these lines and reaches levels up to tenfold higher than in the case of normal cells. Moreover, the ionophore A23187 increased the levels of the lysolipid in the extracellular medium. Extracellular LysoPtdIns was rapidly hydrolyzed to inositol 1:2-cyclic phosphate. LysoPtdIns induced thymidine incorporation in FRT-Fibro Ha-Ras fibroblasts, whereas inositol cyclic 1:2-cyclic phosphate did not affect cell growth per se, nor did it interfere with the LysoPtdIns mitogenic activity. We hypothesize that in Ras-transformed fibroblasts the formation and release of LysoPtdIns may function as an autocrine mechanism that participates in the Ras-dependent stimulation of cell growth.

Signalling pathways involved in the mitogenic action of lysophosphatidylinositol.

Lysophosphatidylinositol has been previously shown to stimulate cell proliferation in differentiated and in K-ras transformed thyroid cells. Increased levels of lysophosphatidylinositol, but not lysophosphatidylcholine or lysophosphatidylethanolamine, are present in thyroid as well as in other ras-transformed cell lines. We have now investigated the mechanism of action of this lysolipid by analysing its effects in a differentiated thyroid cell line. Lysophosphatidylinositol did not increase the levels of cAMP, the main stimulator of cell proliferation in the thyroid, whereas it stimulated phosphoinositide breakdown, mobilization of cytosolic Ca2+ and arachidonic acid release, suggesting that it activates both phospholipases C and A2. None of the effects of lysophosphatidylinositol were prevented by pretreatment of cells with pertussis toxin. Instead, the tyrosine kinase inhibitors, tyrphostins AG18 and AG561, completely blocked its mitogenic action. The effects of lysophosphatidylinositol were distinguishable from those of the well known mitogen lysophosphatidic acid, which affected differently the signalling pathways analysed and was not mitogenic in ras-transformed cells. These results suggest that the mitogenic activity of lysophosphatidylinositol is associated with the activation of phospholipase C and phospholipase A2 and is relatively specific for ras-transformed cells.

Analysis of surveillance systems in place in European Mediterranean countries for West Nile virus (WNV) and Rift Valley fever (RVF).

West Nile virus (WNV) and Rift Valley fever virus (RVFV) represent an important group of viral agents responsible for vector-borne zoonotic diseases constituting an emerging sanitary threat for the Mediterranean Basin and the neighbouring countries. WNV infection is present in several Mediterranean countries, whereas RVF has never been introduced into Europe, but it is considered a major threat for North African countries. Being vector-borne diseases, they cannot be prevented only through an animal trade control policy. Several approaches are used for the surveillance of WNV and RVFV. With the aim of assessing the surveillance systems in place in Mediterranean countries, two disease-specific questionnaires (WNV, RVFV) have been prepared and submitted to Public Health and Veterinary Authorities of six EU countries. This study presents the information gathered through the questionnaires and describes some critical points in the prevention and surveillance of these diseases as emerged by the answers received.

The components of 'One World - One Health' approach.

The interaction between living beings, including men, animals and pathogens, sharing the same environment, should be considered as a unique dynamic system, in which the health of each component is inextricably interconnected and dependent with the others. Nowadays, a new integrated One Health approach is reflecting this interdependence with a holistic view to the ecological system. The One Health approach can be defined as a collaborative and a multidisciplinary effort at local, national and global level to guarantee an optimal healthy status for humans, animals and environment. Strictly related to the One Health concept is to be considered the control of infectious diseases, which have influenced the course of human history. Four different components might be identified as key elements within the 'One World - One Health' (OWOH) approach: the geographical component, the ecological one, the human activities and the food-agricultural ones.

Changes in the levels of glycerophosphoinositols during differentiation of hepatic and neuronal cells.

Glycerophosphoinositols are metabolites formed by a phosholipase A2 and a lysolipase specifically acting on membrane phosphoinositol lipids. High levels of these compounds characterize epithelial cells and fibroblasts transformed by ras and other cellular oncogenes. Here we have analyzed the glycerophosphoinositol levels in cells that are considered models of cell differentiation. Using rat hepatocytes at different stages of liver development we have shown that the glycerophosphoinositol basal levels of fetal cells were up to fourfold higher than in adult hepatocytes. No changes in glycerophosphoinositol were observed in regenerating rat liver, a model of differentiated cells proliferating in a synchronous manner, where only glycerophosphoinositol 4-phosphate increased by 80%. Similarly to fetal hepatocytes, a modest but significant increase (30%) in the levels of glycerophosphoinositols was observed in undifferentiated NG-108-15 cells as compared to the same cells induced to differentiate by cAMP. In a different neuronal cell line, PC12 cells, increased glycerophosphoinositol levels characterized the differentiated cells. Based on these observations we suggest that high glycerophosphoinositol levels characterize cellular phenomena associated with the activation of ras/mitogen-activated protein kinase pathways.