Fluctuations of grass pollen content in the atmosphere of East Perugia and meteorological correlations (year 1989)

Summary Gramineae pollination from a pollen monitoring station located in the eastern suburb of Perugia and meteorological correlations are reported. The data refers to the year 1989. Grass pollen peak pollination was from May to July; in this period the influence of relative humidity and of temperature on pollen concentration was very high. Phenological observations, to identify the time of maximum stamen extension in the most common genera in the area, are also reported. During the period of investigation the counts of pollen grains over four-hour periods showed a regular diurnal rhythm with peaks of concentration in the four-hour period 16.00–20.00. Aerosporological data and meteorological data related to four-hour periods were correlated following different criteria.     

The role of air temperature in determining dormancy release and flowering ofCorylus avellana L.

Summary 7 years of airborne pollen monitoring in Perugia (central Italy) were used to determine the temperature requirements to break dormancy and to resume growth and bloom ofCorylus avellana L.,Corylus needs 1000 chill-units to complete its dormancy and this value, in the Perugian area, is met by the end of December or the first days of January. MoreoverCorylus trees require 220 growth degree hours before they are able to flower. If air temperature is high, this value can be achieved in only 10 days, but if the temperature remains too low, the heat accumulation can require up to 35 days. With these parameters it is possible to build a model to predict the date of the beginning ofCorylus avellana pollen season.     

The results of 2-year pollen monitoring of an urban network in Perugia,Central Italy

Continuous pollen monitoring of an urban network consisting of three stations has been undertaken for a period of 2 years in Perugia, central Italy. The aim has been to establish whether the Perugia pollen trap, active since 1983, is still representative of the area following recent urbanisation. Quantitative differences were found between the stations, reflecting different vegetational areas, but only slight differences were detected in relation to the timing of the principal period of pollination. Therefore, although individual pollen traps are necessary to characterize fully the different areas, one trap is sufficient to determine the key allergenic thresholds in the studied area.     

The results of 2-year pollen monitoring of an urban network in Perugia,Central Italy

Continuous pollen monitoring of an urban network consisting of three stations has been undertaken for a period of 2 years in Perugia, central Italy. The aim has been to establish whether the Perugia pollen trap, active since 1983, is still representative of the area following recent urbanisation. Quantitative differences were found between the stations, reflecting different vegetational areas, but only slight differences were detected in relation to the timing of the principal period of pollination. Therefore, although individual pollen traps are necessary to characterize fully the different areas, one trap is sufficient to determine the key allergenic thresholds in the studied area.     

Time linkages between pollination onsets of different taxa over an 11-year period in Perugia,Central Italy

Times of pollination of different taxa in the atmosphere of Perugia (Central Italy) over an 11-year period (1982–1992) were recorded and analysed by means of a 7-day volumetric Hirst-type pollen trap. For some taxa, the pollination period varied from year to year from a chronological and/or quantitative point of view. Several taxa showed a linkage in their starting dates of pollination. Knowledge of this kind of linkage allows us to build a forecasting model.     

Changes in protein and carbohydrate content during development of seeds and siliquas of rapeseed (Brassica napus L.)

Abstract

A study was made on the changes observed in the protein, starch and soluble sugar content during development of siliquas and seeds of rapeseed grown in central Italy.

Concentration of starch and soluble sugars in the seed increases to 75 per cent dry matter during the first few weeks of pod development and then drops to minimum values. The protein increases steadily until maturity, when a level of 0.85 mg per seed is reached, equivalent to 18 per cent dry matter. The protein and starch in the hull? decrease continuously during development, while in the initial stages the soluble sugars are accumulated until they account for 33 per cent dry matter, after which they decline towards maturity.     

Differences in atmospheric trees pollen seasons in winter, spring and summer in two European geographic areas, Spain and Italy

The global climate change reported over recent years may prompt changes in the atmospheric pollen season (APS). The aim of this study is to evaluate the possible impact provoked by meteorological conditions variations at different seasons of the year or different geographical areas on APS. Alnus, Betula and Castanea atmospheric pollen seasons and trends during the last 17 years at Ourense and Vigo (Galicia—NW Spain) and Perugia (Italy) were analysed. Possible incidence of the meteorological trends observed in the different cities on the atmospheric pollen seasons and the chill and heat requirements were evaluated. Pollen data from Ourense, Vigo and Perugia (1995–2011) were used. Pollen sampling was performed using LANZONI VPPS 2000 volumetric traps (Hirst in Ann Appl Biol 36:257–265, 1952), placed on top of different buildings at a similar height from the ground. Several methods, dates and threshold temperatures for determining the chill and heat requirements needed to trigger flowering were tested. Different temporary order in the pollination sequence was observed between the three pollen types studied in the three sites. Alnus flowers few days in advance in Ourense respecting to Vigo and 1 month earlier than Perugia. The Betula flowering start date in Ourense and Vigo is almost simultaneous, taking place only 5 days in advance with respect to Perugia. Finally, scarce differences in the APS onset of Castanea were detected between the three cities. The variations observed among the two areas (Umbria, Italy and Galicia, Spain) in the onset of pollen season in the winter or spring flowering trees could be explained by differences in the thermal requirements needed for flowering as consequence of the climatic conditions recorded during the previous period to flowering. The length of the chilling and heat period as well as the thermal requirements obtained showed differences between geographical areas. The chill requirements accumulated were higher in Perugia than Ourense and Vigo. By contrary, the lowest heat accumulation was achieved in Perugia. The observed trends in the APS characteristics and the weather-related parameters were not homogeneous both in the pollen types and sites. The pollen index of Betula and Castanea pollen in Ourense shows a significant trend to increase.     

High-resolution real-time recording with microelectrode biosensors reveals novel aspects of adenosine release during hypoxia in rat hippocampal slices

We have used improved miniaturized adenosine biosensors to measure adenosine release during hypoxia from within the CA1 region of rat hippocampal slices. These microelectrode biosensors record from the extracellular space in the vicinity of active synapses as they detect the synaptic field potentials evoked in area CA1 by stimulation of the afferent Schaffer collateral-commissural fibre pathway. Our new measurements demonstrate the rapid production of adenosine during hypoxia that precedes and accompanies depression of excitatory transmission within area CA1. Simultaneous measurement of adenosine release and synaptic transmission gives an estimated IC50 for adenosine on transmission in the low micromolar range. However, on reoxygenation, synaptic transmission recovers in the face of elevated extracellular adenosine and despite a post-hypoxic surge of adenosine release. This may indicate the occurrence of apparent adenosine A1 receptor desensitization during metabolic stress. In addition, adenosine release is unaffected by pharmacological blockade of glutamate receptors and shows depletion on repeated exposure to hypoxia. Our results thus suggest that adenosine release is not a consequence of excitotoxic glutamate release. The potential for adenosine A1 receptor desensitization during metabolic stress implies that its prevention may be beneficial in extending adenosine-mediated neuroprotection in a variety of clinically relevant conditions.     

Venom from Anemesia species of spider modulates high voltage-activated Ca(2+) currents from rat cultured sensory neurones and excitatory post synaptic currents from rat hippocampal slices

The actions of crude venom from Anemesia species of spider were investigated in cultured dorsal root ganglion neurones from neonatal rats and hippocampal slices. Using mass spectrometry (MALDI-TOF MS), 10-12 distinct peptides with masses between about 3 and 10kDa were identified in the crude spider venom. At a concentration of 5 microg/ml crude Anemesia venom transiently enhanced the mean peak whole cell voltage-activated Ca(2+) current in a voltage-dependent manner and potentiated transient increases in intracellular Ca(2+) triggered by 30mM KCI as measured using Fura-2 fluorescence imaging. Additionally, 5-8 microg/ml Anemesia venom increased the amplitude of glutamatergic excitatory postsynaptic currents evoked in hippocampal slices. Omega-Conotoxin GVIA (1 microM) prevented the increase in voltage-activated Ca(2+) currents produced by Anemesia venom. This attenuation occurred when the cone shell toxin was applied before or after the spider venom. Anemesia venom (5 microg/ml) created no significant change in evoked action potentials but produced modest but significant inhibition of voltage-activated K(+) currents. At a concentration of 50 microg/ml Anemesia venom only produced reversible inhibitory effects, decreasing voltage-activated Ca(2+) currents. However, no significant effects on Ca(2+) currents were observed with a concentration of 0.5 microg/ml. The toxin(s) in the venom that enhanced Ca(2+) influx into sensory neurones was heat-sensitive and was made inactive by boiling or repetitive freeze-thawing. Boiled venom (5 microg/ml) produced significant inhibition of voltage-activated Ca(2+) currents and freeze-thawed venom inhibited Ca(2+) transients measured using Fura-2 fluorescence. Our data suggest that crude Anemesia venom contains components, which increased neuronal excitability and neurotransmission, at least in part this was mediated by enhancing Ca(2+) influx through N-type voltage-activated Ca(2+) channels.     

A neural protection racket: AMPK and the GABA(B) receptor

The cellular energy-sensing kinase AMPK is known to be activated in neurons in response to metabolic insults, but the downstream consequences have been unclear. A study by Kuramoto and colleagues in this issue of Neuron favors the idea that AMPK activation is neuroprotective, and suggests a potential mechanism for this effect involving phosphorylation of the GABA(B) receptor.