Co-exposure to highly allergenic airborne pollen and fungal spores in Europe.

The study is aimed at determining the potential spatiotemporal risk of the co-occurrence of airborne pollen and fungal spores high concentrations in different bio-climatic zones in Europe. Birch, grass, mugwort, ragweed, olive pollen and Alternaria and Cladosporium fungal spores were investigated at 16 sites in Europe, in 2005-2019. In Central and northern Europe, pollen and fungal spore seasons mainly overlap in June and July, while in South Europe, the highest pollen concentrations occur frequently outside of the spore seasons. In the coldest climate, no allergy thresholds were exceeded simultaneously by two spore or pollen taxa, while in the warmest climate most of the days with at least two pollen taxa exceeding threshold values were observed. The annual air temperature amplitude seems to be the main bioclimatic factor influencing the accumulation of days in which Alternaria and Cladosporium spores simultaneously exceed allergy thresholds. The phenomenon of co-occurrence of airborne allergen concentrations gets increasingly common in Europe and is proposed to be present on other continents, especially in temperate climate.

Plant biodiversity assessment through pollen DNA metabarcoding in Natura 2000 habitats (Italian Alps).

Monitoring biodiversity is of increasing importance in natural ecosystems. Metabarcoding can be used as a powerful molecular tool to complement traditional biodiversity monitoring, as total environmental DNA can be analyzed from complex samples containing DNA of different origin. The aim of this research was to demonstrate the potential of pollen DNA metabarcoding using the chloroplast trnL partial gene sequencing to characterize plant biodiversity. Collecting airborne biological particles with gravimetric Tauber traps in four Natura 2000 habitats within the Natural Park of Paneveggio Pale di San Martino (Italian Alps), at three-time intervals in 1 year, metabarcoding identified 68 taxa belonging to 32 local plant families. Metabarcoding could identify with finer taxonomic resolution almost all non-rare families found by conventional light microscopy concurrently applied. However, compared to microscopy quantitative results, Poaceae, Betulaceae, and Oleaceae were found to contribute to a lesser extent to the plant biodiversity and Pinaceae were more represented. Temporal changes detected by metabarcoding matched the features of each pollen season, as defined by aerobiological studies running in parallel, and spatial heterogeneity was revealed between sites. Our results showcase that pollen metabarcoding is a promising approach in detecting plant species composition which could provide support to continuous monitoring required in Natura 2000 habitats for biodiversity conservation.

Identifying patterns of airborne pollen distribution using a synoptic climatology approach.

Understanding the mechanisms of pollen release and dispersion in the atmosphere is of high importance, not only for getting an insight on the patterns of movement of these biological particles that are necessary for plants' reproduction, but also because exposure to airborne pollen is a major concern for respiratory allergies worldwide. In this work, a synoptic circulation-to-environment classification method was adopted to elucidate the relationship between distinct atmospheric patterns and pollen levels for the 11 most abundant but also allergenic taxa in Thessaloniki, Greece, for the 15-year period 1987-2001. It was found that the NW1 depressional weather type is associated with the "low winter pollen season" and high levels of pollen from Carpinus spp., Corylus spp., Cupressaceae, Platanus spp., Pinaceae, Quercus spp. and Urticaceae. In contrast, the SW1 cyclonic type is linked to the "high spring-summer pollen season" and high levels of pollen from Oleaceae and Urticaceae. On the other hand, anticyclonic weather is associated with the "summer-autumn pollen season" and high levels of Poaceae and Chenopodiaceae pollen in the atmosphere. Regional transport of Alnus pollen is linked to a strong high-pressure system centered over Italy, giving light NE winds over northern Greece. These findings shed light to the synoptic climatology of airborne pollen in Thessaloniki and could feed early-warning systems for alerting vulnerable groups of the allergic population.

Temperature-related changes in airborne allergenic pollen abundance and seasonality across the northern hemisphere: a retrospective data analysis.

BACKGROUND: Ongoing climate change might, through rising temperatures, alter allergenic pollen biology across the northern hemisphere. We aimed to analyse trends in pollen seasonality and pollen load and to establish whether there are specific climate-related links to any observed changes. METHODS: For this retrospective data analysis, we did an extensive search for global datasets with 20 years or more of airborne pollen data that consistently recorded pollen season indices (eg, duration and intensity). 17 locations across three continents with long-term (approximately 26 years on average) quantitative records of seasonal concentrations of multiple pollen (aeroallergen) taxa met the selection criteria. These datasets were analysed in the context of recent annual changes in maximum temperature (Tmax) and minimum temperature (Tmin) associated with anthropogenic climate change. Seasonal regressions (slopes) of variation in pollen load and pollen season duration over time were compared to Tmax, cumulative degree day Tmax, Tmin, cumulative degree day Tmin, and frost-free days among all 17 locations to ascertain significant correlations. FINDINGS: 12 (71%) of the 17 locations showed significant increases in seasonal cumulative pollen or annual pollen load. Similarly, 11 (65%) of the 17 locations showed a significant increase in pollen season duration over time, increasing, on average, 0·9 days per year. Across the northern hemisphere locations analysed, annual cumulative increases in Tmax over time were significantly associated with percentage increases in seasonal pollen load (r=0·52, p=0·034) as were annual cumulative increases in Tmin (r=0·61, p=0·010). Similar results were observed for pollen season duration, but only for cumulative degree days (higher than the freezing point [0°C or 32°F]) for Tmax (r=0·53, p=0·030) and Tmin (r=0·48, p=0·05). Additionally, temporal increases in frost-free days per year were significantly correlated with increases in both pollen load (r=0·62, p=0·008) and pollen season duration (r=0·68, p=0·003) when averaged for all 17 locations. INTERPRETATION: Our findings reveal that the ongoing increase in temperature extremes (Tmin and Tmax) might already be contributing to extended seasonal duration and increased pollen load for multiple aeroallergenic pollen taxa in diverse locations across the northern hemisphere. This study, done across multiple continents, highlights an important link between ongoing global warming and public health-one that could be exacerbated as temperatures continue to increase. FUNDING: None.

Changes to airborne pollen counts across Europe.

A progressive global increase in the burden of allergic diseases has affected the industrialized world over the last half century and has been reported in the literature. The clinical evidence reveals a general increase in both incidence and prevalence of respiratory diseases, such as allergic rhinitis (common hay fever) and asthma. Such phenomena may be related not only to air pollution and changes in lifestyle, but also to an actual increase in airborne quantities of allergenic pollen. Experimental enhancements of carbon dioxide (CO[Formula: see text]) have demonstrated changes in pollen amount and allergenicity, but this has rarely been shown in the wider environment. The present analysis of a continental-scale pollen data set reveals an increasing trend in the yearly amount of airborne pollen for many taxa in Europe, which is more pronounced in urban than semi-rural/rural areas. Climate change may contribute to these changes, however increased temperatures do not appear to be a major influencing factor. Instead, we suggest the anthropogenic rise of atmospheric CO[Formula: see text] levels may be influential.

Parietaria judaica flowering phenology, pollen production, viability and atmospheric circulation, and expansive ability in the urban environment: impacts of environmental factors.

Parietaria judaica (Urticaceae) grows abundantly in urban areas of the Mediterranean region. Its pollen is a major allergy source. We studied the species' distribution and abundance in and around Thessaloniki (Greece), pollen production and pollen season. We also examined how urban pollution affects pollen viability. Our ultimate goal was to obtain an estimate of the species' performance and ability to expand under different environmental conditions related to climate change. We mapped P. judaica and the other Urticaceae species. In a north- and a south-facing population, we recorded the progress of P. judaica flowering and estimated the pollen content per flower, shoot and surface unit. We concurrently assessed atmospheric circulation of Urticaceae pollen. We estimated P. judaica pollen viability and Cu, Pb and Zn concentrations in plants collected from sites differing in traffic intensity. P. judaica is the most abundant Urticaceae species in the area; its occurrence has increased dramatically over the last 100 years. Production of flowers is intense in spring and autumn. Flowering started 12 days earlier in the south-facing population in spring, and 3 days later in autumn. Pollen production was higher in spring and in the south-facing population. Flower and pollen production were positively correlated with the size of the plant and the flower, respectively. Copper and lead concentrations in plants were positively correlated with pollen viability, which was higher for plants collected from high-traffic sites. P. judaica has a high phenotypic plasticity; this is a feature that promotes success of expansive and invasive species. It is also well adapted to warm and polluted urban environments. The climatic change forecast for the Mediterranean region could provoke earlier, longer, and more pronounced flowering and, consequently, more P. judaica pollen in the air. In return, this would result in increased severity of Parietaria pollinosis.

Assessing the local anesthetic effect of five essential oil constituents.

We studied the effects of five monoterpenoids, viz. 1,8-cineole, fenchone, linalool, p-cymene and α-pinene, on the sciatic nerve fibers of the frog Rana ridibunda (Pallas, 1771) and compared them to that of lidocaine, a standard local anesthetic. The isolated sciatic nerve, with its perineurium intact, was placed in a three-chambered recording bath, which allowed us to monitor the compound action potentials (CAP), stable in amplitude, for over 2 days. The half-vitality time (IT(50)), which is the time required for the amplitude of the CAP to decrease to 50% of its control value, was 53.5 ± 0.9 h for a nerve incubated in normal saline at 26.0 °C. The IT(50) values for nerves incubated in saline with p-cymene, 1,8-cineole, or α-pinene, at 30.0 mM, were 19.9 ± 0.4, 32.9 ± 0.5, and 31.0 ± 0.3 hours, respectively. As the IT(50) value for 30.0 mM lidocaine, a standard local anesthetic, was 1.6 ± 0.3 min under the same conditions, these three compounds cannot be considered as having a local anesthetic effect. The IT(50) values for 30.0 mM linalool and fenchone were 5.7 ± 0.6 and 15.4 ± 1.1 min, respectively; they were significantly, but not markedly different from the respective value for lidocaine. These results combined with the fast inhibition of the CAP and its fast recovery after the removal of either linalool or fenchone indicate a local anesthetic activity of the two compounds. Linalool retained this activity even at lower concentrations of 15.0 and 7.5 mM. The local anesthetic effects of lidocaine and linalool were concentration-dependent; this was not the case for fenchone, which had a relatively strong local anesthetic activity at 30.0 mM, but was entirely inactive at 25.0 mM. On the basis of the effects of the five monoterpenoids on the electrophysiological properties of the sciatic nerve fibers of the frog, we conclude that, whereas 1,8-cineole, p-cymene and α-pinene cause only minor effects, linalool and fenchone exhibit acute local anesthetic activity.