Erk-dependent cytosolic phospholipase A2 activity is induced by CD95 ligand cross-linking in the mouse derived Sertoli cell line TM4 and is required to trigger apoptosis in CD95 bearing cells

In the present study we demonstrated that CD95L cross-linking generated reverse signalling in the mouse derived Sertoli cell line TM4. Treatment of TM4 cells with mAb anti-CD95L induced activation of the cytosolic phospholipase A2 (cPLA2). Cytosolic PLA2 activation was controlled by the MAPK pathway as indicated by the ability of the specific MEK inhibitor, PD098059, to abolish cPLA2 activation. In addition, Western blot experiments showed a rapid increase in phosphorylated Erk1/2 following CD95L cross-linking, while no effect on the phosphorylation of other MAPK, p38 or JNK, was observed. CD95L cross-linking by mAb increased the levels of soluble CD95L and apoptotic activity of TM4 cell supernatants, which was blocked by co-incubation with the PLA2 inhibitor, AACOCF3 or PD098059. Finally, pre-treatment of TM4 cells with AACOCF3 or PD098059 completely abolished TM4-induced apoptosis of Jurkat T cells, thus indicating that the Erk/cPLA2 pathway is required for CD95L-induced apoptosis.     

Habitat selection and group formation pattern of fallow deer Dama dama in a submediterranean environment

We analyzed the patterns of association between sex and age classes of fallow deer Dama dama in addition to the modification of aggregation patterns as a function or the degree of cover in different habitats in a coastal submediterranean environment in Italy. Deer preferred large open grasslands, small clearings, woods and marshes. Habitat selection varied strongly according to sex, and there were also ecological differences among males of different age classes. Adult females were mostly in family groups, with subadults and fawns. These groups were very stable in time and space. On the contrary bachelor herds were unstable social associations, adapting their size to the local degree of cover. In open grasslands males and females sometimes formed mixed groups with group size similarly being adapted to degree of cover. The possibility that random events fully explained fallow deer aggregation patterns was excluded, while the existence of non-linear mechanisms of aggregation was shown. The persistence of antipredator strategies in this managed population may account for these findings.     

Growth of the seaweed Ulva rigida C. Agardh in relation to biomass densities, internal nutrient pools and external nutrient supply in the Sacca di Goro lagoon (Northern Italy)

Growth of the seaweed Ulva rigida C. Agardh was investigated in relation to biomass densities, internal nutrient pools and external nutrient supply. Research was carried out from 23 March to 5 July 1994 in the Sacca di Goro (Po Delta, Northern Italy), whose south-eastern part was covered by extensive mats of Ulva rigida. Two types of field experiments were conducted by incubating Ulva thalli inside large cages. In the first experiment, beginning on 23 March, 100 g of wet thalli were placed into the cages, allowed to grow for two weeks, then collected and replaced. This procedure was repeated 8 times over the study period. In the second experiment, Ulva thalli were left inside the cages and collected at selected time intervals (14, 27, 41, 64 and 76 days) in order to simulate the effects of increased density on growth and nutrient storage.We recorded specific growth rates (NGR) ranging from 0.025 to 0.081 d^–1 for a period up to two months in the repeated short-term experiments performed at relatively low initial algal densities (300–500 g AFDW m^–3). These NGR resulted significantly related to dissolved inorganic nitrogen (DIN) in the water column. Tissue concentrations of total Kjeldahl nitrogen (TN) were almost constant, while extractable nitrate decreased in a similar manner to DIN in the water column. Total phosphorus showed considerable variation, probably linked to pulsed freshwater inflow.In the long-term incubation experiment, NGR of Ulva was inversely related to density. Internal concentrations of both total P and TN reached maximum values after one month; thereafter P concentration remained almost constant, while TN decreased below 2% w/w (by dry weight). The TN decrease was also accompanied by an abrupt decrease in nitrate tissue concentration. The biomass incubated over the two month period suffered a progressive N limitation as shown by a decreasing NY ratio (49.4 to 14.6). The reciprocal control of Ulva against biogeochemical environment and viceversa is a key factor in explaining both resource competition and successional stages in primary producer communities dominated by Ulva. However, when the biomass exceeds a critical threshold level, approximately 1 kg AFDW m^–3, the macroalgal community switches from active production to rapid decomposition, probably as a result of selfshading, biomass density and development of anaerobic conditions within the macroalgal beds.     

Lysinium,argininum, glutamate,and aspartate ions in water solution

SCF-LCAO-MO ab initio calculations were carried out for the interaction between a charged amino acid and a water molecule. The results obtained were fitted by an analytical potential function of the atom–atom type, and the corresponding potential surfaces were examined by means of orientationally optimized isoenergy contour maps. Monte Carlo simulations were also carried out on a few selected solute–water clusters at T = 300 K, in order to obtain insight into the solvation structure.     

Study on major mite allergens in Italian homes

Summary There has always been a great interest for allergologists in the relation between the exsposure to allergic pollens a/o perennials and allergic symptomatology. Indeed the allergologist is constantly looking for clear evidence to what is shown or suggested by clinical history and routine allergologic tests.At present the availability of reliable quantitative analytical methods has given us the possibility of making a study on the presence of house mite and cat allergens in Italian homes.The study involved 5 Italian towns and was carried out in autumn months and the collection of samples has been made with a simple retail electric vacuum cleaner. The dosage of the allergenic content of the dust has been carried out by an immunoassay using specific monoclonal antibodies and a mixture of allergic patients' sera and a monoclonal anti IgE antibody coupled with an enzyme. The results suggest a wide variability of the allergenic content of the samples coming from the same geographical area but a constant ratio between the major mite allergens (Der I/Der II) ranging around a value 21.The prevalence of one mite species over another is variable, and depends on the geographical locality.     

The ultrastructure of the zygospore in Endogone flammicorona Trappe & Gerdemann

The ultrastructural organization of the spores of the sporocarp of Endogone flammicorona was studied. Two types of organization are described. Initially the spore possessed a vacuolate protoplasm and was bound by two cell wall layers. The spore was surrounded by a hyphal mantle formed of a sheet of vacuolized hyphae with uniformly thin walls. Secondly, although the ultrastructural features of the spore appeared the same, it was now surrounded by a hyphal mantle with unevenly thickened walls (i. e., the so-called flaming crown) due to the gradual and irregular deposition of granules and lamellae. This crown gives the spore its most commonly observed morphological feature and is the preminent character employed taxonomically to speciate Endogone flammicorona Trappe & Gerdemann.     

Pigeon navigation: Site simulation by means of atmospheric odours

Summary 10 experiments were conducted in which a group of experimental pigeons were allowed to smell natural ambient air for a period of 3 h at a site which was 25–55 km away from the loft (false site) and then subsequently released at another site ( true release site ) situated in a roughly diametrical position from home. Controls were directly transported to the true release site, and during the same 3 h period they were allowed to smell natural air there. Except for those 3 h, both controls and experimentals were prevented from smelling atmospheric odours by filtration of the air flowing through the containers in which the birds were held. Air filtration was never interrupted in a third group of birds, which were transported together with the experimentals. All the birds were released under local anaesthesia of their olfactory mucosae. Experiments were performed in pairs: Within each pair of experiments, the site used as false site in the first experiment was the true release site in the second and vice versa.On average, initial bearings of the controls were homeward oriented. Bearings of experimentals, which smelled natural air at the false site, were oriented, with similar accuracy, towards a compass direction pointing from this false site to home, and hence these birds actually flew predominantly away from home (Fig. 4). The third group of pigeons, which never could smell natural air, differed from both of the others in their initial orientation.Faster homing speeds were significantly more frequent in the controls than in the other two treatment types. Experimentals that had smelled falsesite odours were slowest.Thus, pigeons not only can be prevented from orienting their courses homeward by elimination of certain substances from the breathing air, but they also can be systematically misguided by false olfactory information.There was no indication that site-specific stimuli independent of olfaction might additionally be necessary for site localization in pigeons.     

Toxicity and genotoxicity of surface water before and after various potabilization steps

Many studies have revealed the presence of compounds with genotoxic activity in drinking water by means of short-term mutagenicity tests. In this study, the influence of the different steps of surface water treatment on the mutagenicity of drinking water was evaluated. Four different types of samples were collected: raw lake water, water after pre-disinfection with chlorine dioxide, water after filtration on granular activated carbon, and tap water. Water extracts underwent a bacterial toxicity test (Microtox test) and different in vitro genotoxicity tests: a test with Salmonella typhimurium strains, a Saccharomyces cerevisiae test, the SOS Chromotest with Escherichia coli and the Mutatox test with Vibrio fischeri. The Microtox test revealed high toxicity in the treated water samples. The disinfection steps increased the toxicity: the Mutatox test confirmed these results and the Salmonella/microsome test at the highest doses showed toxicity that could conceal mutagenicity. The SOS Chromotest was positive in all treated water samples without metabolic activation. In the test with S. cerevisiae both toxicity and genotoxicity generally increased during the water treatment steps, especially in cells without induction of cytochrome P450.