Emma Tedeschini

Ozone affects pollen viability and NAD(P)H oxidase release from Ambrosia artemisiifolia pollen

Air pollution is frequently proposed as a cause of the increased incidence of allergy in industrialised countries. We investigated the impact of ozone (O3) on reactive oxygen species (ROS) and allergen content of ragweed pollen (Ambrosia artemisiifolia). Pollen was exposed to acute O3 fumigation, with analysis of pollen viability, ROS and nitric oxide (NO) content, activity of nicotinamide adenine dinucleotide phosphate (NAD[P]H) oxidase, and expression of major allergens. There was decreased pollen viability after O3 fumigation, which indicates damage to the pollen membrane system, although the ROS and NO contents were not changed or were only slightly induced, respectively. Ozone exposure induced a significant enhancement of the ROS-generating enzyme NAD(P)H oxidase. The expression of the allergen Amb a 1 was not affected by O3, determined from the mRNA levels of the major allergens. We conclude that O3 can increase ragweed pollen allergenicity through stimulation of ROS-generating NAD(P)H oxidase.

Bridging allergologic and botanical knowledge in seasonal allergy: a role for phenology

BACKGROUND Grass pollen is a worldwide cause of respiratory allergy. Identifying the causative species is essential, for example for choosing the appropriate immunotherapy, because not all grass allergens are totally cross-reacting, and the pollen calendars provide only a gross estimate. Phenologic analyses allow identification of the pollen release for each individual grass. OBJECTIVES To assess, using phenologic analyses, the true flowering periods of grasses and to compare the data with the standard pollen calendar. METHODS Phenologic analyses were performed of the following grasses: black grass, sweet vernal grass, common wild oat, barren brome, cocksfoot, tall fescue, Yorkshire fog, ryegrass, Timothy grass, bulbous meadow-grass, Kentucky bluegrass, and Bermuda grass. Sampling was performed every 10 days, starting in April 2009, at 50 stations distributed across Italy. The flowering phase was assessed using a stereomicroscopy-based method for the detection of spreading stamens. The official pollen calendar was used for comparison. RESULTS Relevant differences were found between grass pollen count and effective flowering of the grass species. Only some species contributed to the pollen peak, and a relevant pollen load for other species was also present out of the peak. Important Pooideae, such as Timothy grass, were not present during the pollen peak in northern and central Italy, and the same occurred with Bermuda grass. CONCLUSIONS The various species of grasses release their pollen grains at different times during the pollen season, and this information is missing with pollen calendars. This may have a relevant effect on the choice of an appropriate immunotherapy.

The influence of climate changes in Platanus spp. pollination in Spain and Italy

There is evidence of a significant increase in air temperature in the northern hemisphere over recent decades, with consequent changes for anemophilous pollen. In this work we present the effects of climatic change on Platanus spp. pollination in different areas of Italy and Spain, characterized by different climates. In particular, the historical series of pollen monitoring and meteorological data of two Italian stations, Perugia (1982 – 2003) and Torino (1985 – 2003), and two Spanish stations, Santiago de Compostela (1992 – 2003) and Vigo (1994 – 2003), were analysed. The changes recorded in all stations included the timing and behaviour of pollen release. However, no or minimal influence on the total pollen emission was found. Research has linked the changes in phenological events to an increase in temperature, moreover in this study temperature changes are believed to be mainly responsible for the variations recorded in the pollen season of Platanus. A previous start of pollination (−0.66; −1.21; days/year) is reported in both Italian stations where the temperatures have significantly increased and a delay of 0.2 – 0.8 days/year in Spanish stations where a different trend of temperature is recorded. Other important data is given regarding the type of discharge of pollen grains during the pollen season. Pollination curves are examined by two statistical shape parameters (kurtosis and skewness) which show that pollen release is more gradual with higher temperatures or faster under colder conditions. A regression analysis links the atmospheric pollen presence to mean air temperature.

Airborne pine (Pinus spp.) pollen in the atmosphere of Perugia (Central Italy): Behaviour of pollination in the two last decades

The phenology of many species, which grow intemperate climate, is principally regulated bythe temperature and the plants respond withvariations in the beginning, in the durationand in the intensity of the various phenophasestowards every climate change. We have analysedthe data of Pinus pollination in Perugia,Central Italy, during last 2 decades(1982–2001), in a period during which theannual mean temperature significantly increasedby about 0.8 °C.The pine pollination started, on average,between the end of March and mid-April andended in the last days of June, with a meanduration of 65 days. The start dates showed asignificant negative correlation with theaverage air temperature in March andsignificant trends towards an earlier beginningof pollination by 18 days (−0.9 day/year) and ashorter duration of the pollen season by 10days (−0.6 day/year) were found over thestudied period. Moreover, the trend of thedaily pollen counts showed, on average, analmost normal distribution, but the analysis ofeach yearly trend revealed significantdifferences correlated with the meantemperature during the pollen season. Theseobserved trends in pine pollination suggest theuse of aerobiological monitoring of thisairborne pollen as indicator of temperaturechange in Central Italy over a relatively longperiod.

Cloning and expression analysis of a Petunia hybrida flower specific mitotic-like cyclin.

A cyclin cDNA clone (Pethy;CycB1;1) was isolated from a Petunia hybrida ovary specific cDNA library. Sequence comparison revealed that Pethy;CYCB1;1 protein is highly homologous to mitotic B1 cyclins. Northern analysis and in situ hybridisation experiments showed that its expression is developmentally regulated and restricted to flower organs. We have attempted to define some of the cell division patterns which contribute to shaping each floral organ by analysing Pethy;CycB1;1 expression on Petunia flower sections. While in sepals, epidermis and parenchyma cell division patterns were comparable, there were two distinct cell division patterns in petals. In the epidermis, Pethy;CYCB1;1 expression was found both at the petal tip and along epidermis, whereas in the parenchyma only at the petal tips. In reproductive organs cell divisions were detected only in sporophytic tissues. No signals were detected inside meiotic cells.

Volume changes in the pollen grain of Corylus avellana L. (Corylaceae) during development

Pollen development in 8‐year‐old hazel plants (Corylus avellana L.) from Central Italy was monitored in order to investigate the chilling completion date of the catkins. Meiotic division occurred in September and pollen development continued until mid‐October when the first haploid mitosis divisions were observed. The catkins elongated gradually during the summer until mid‐October when their growth slowed. In mid‐December the catkins resumed rapid growth and released pollen. From the end of October the pollen grain volume decreased by 12% on average, reaching its minimum value on 6th November. From this time onwards volume increased again to reach its maximum value at the beginning of December, just before pollination. In mid‐October the daily mean temperature dropped below 12.4°C and remained at this low level during the succeeding period; a relatively high mean temperature, above 4.5°C, was recorded in the second week of December. The beginning of dormancy could be correlated with the slowing down of ca...

Histological investigation on gall development induced by a worldwide invasive pest, Dryocosmus kuriphilus, on Castanea sativa

The Asian chestnut gall wasp Dryocosmus kuriphilus (Hymenoptera: Cynipidae) is one of the most serious pests of chestnut trees worldwide. Wasps lay eggs into chestnut buds from mid Jane to late July, depending on latitude, and galls develop the following spring on new vegetation, reducing photosynthesis and nut production. We observed that modification of tissues surrounding D. kuriphilus eggs, which differentiate to form the larval chamber, started approximately 1 month after oviposition, shortly after eggs hatch. The larval chambers continued to increase slightly in size throughout the autumn months until January. After that, a period of stagnation, which corresponds to the plants dormancy, occurred, followed by rapid growth from March to May, during the period from bud swelling to bud break. Galls continued to grow during the leaf expansion after bud break and stopped when plant organs achieved their final size. Our results have implications for the management of the pest, providing a better understanding of the critical time periods for the effective control.

Phenological analysis of grasses (Poaceae) as a support for the dissection of their pollen season in Perugia (Central Italy)

Grasses (Poaceae) pollen is a major cause for allergic diseases worldwide. Pollen monitoring in the atmosphere is of primary importance for symptoms interpretation and therapy planning. Microscopic pollen identification and counts do not allow the detection at species or genus level because of the stenopalynous nature of the family. Nevertheless, the assessment of the flowering phenology of different species would be important, because not all grass allergens are cross-reacting and allergic patients could be differentially sensitized. In this work, a phenological survey was carried out in five stations located on the urban territory of Perugia (Central Italy), from April to September 2015, recording the alternation between flowering phenophases of 19 grass species and estimating their contribution to the airborne pollen load of the area through the calculation of a Phenological Index. Moreover, pollen grains of the different species were collected and observed, confirming the impossibility to make a discrimination during microscope pollen counts. The prevailing grasses in terms of contribution to the pollen detection in the studied area resulted to be Dactylis glomerata and Lolium perenne during spring and early summer, and Cynodon dactylon during late summer. Data should be validated repeating the survey in successive years and possibly using biomolecular tools, but the obtained information could be relevant for diagnosis and treatment of grass pollen allergies.

Time linkages between pollination onsets of different taxa in Perugia, Central Italy--an update.

INTRODUCTION AND OBJECTIVE In the last decades, increasing attention has been paid to pollinosis. Numerous studies have been carried out concerning the pollination timing of allergenic plant species and the possibility to forecast its beginning and intensity using several statistical methods and models. This study proposes a simple and fast method to identify in advance the time lapse in which the pollination of some allergenic taxa should start. MATERIALS AND METHODS The times of pollination of 14 taxa were recorded in the area of Perugia (Central Italy) by means of a 7-volumetric Hirst-Type pollen trap. For a 30-year period (1984-2013), annual starting dates were calculated for each taxa, using the 5% method (Lejoly-Gabriel). The time linkages between these starting dates were then estimated, considering them in pairs and calculating linear regression coefficients. RESULTS For the significantly linked species, forecasting models were obtained by means of linear regression analysis. To apply these models to the ongoing pollen season, pollination beginning of the earlier species has to be calculated using a sum-based method. From this date, through the obtained equations, it is possible to predict the approximate period in which the pollination of the second linked taxa should start. CONCLUSIONS The possibility to predict the start of the pollen season of these taxa could be of great importance from the allergological point of view. In fact, an early or delayed flowering can have considerable effects in the prophylaxis programming and efficacy.

New biomolecular tools for aerobiological monitoring: Identification of major allergenic Poaceae species through fast real-time PCR

Abstract Grasses (Poaceae) are very common plants, which are widespread in all environments and urban areas. Despite their economical importance, they can represent a problem to humans due to their abundant production of allergenic pollen. Detailed information about the pollen season for these species is needed in order to plan adequate therapies and to warn allergic people about the risks they take in certain areas at certain moments. Moreover, precise identification of the causative species and their allergens is necessary when the patient is treated with allergen‐specific immunotherapy. The intrafamily morphological similarity of grass pollen grains makes it impossible to distinguish which particular species is present in the atmosphere at a given moment. This study aimed at developing new biomolecular tools to analyze aerobiological samples and identifying major allergenic Poaceae taxa at subfamily or species level, exploiting fast real‐time PCR. Protocols were tested for DNA extraction from pollen sampled with volumetric and gravimetric methods. A fragment of the matK plastidial gene was amplified and sequenced in Poaceae species known to have high allergological impact. Species‐ and subfamily‐specific primer–probe systems were designed and tested in fast real‐time PCRs to evaluate the presence of these taxa in aerobiological pollen samples. Species‐specific systems were obtained for four of five studied species. A primer–probe set was also proposed for the detection of Pooideae (a grass subfamily that includes also major cereal grains) in aerobiological samples, as this subfamily includes species carrying both grass allergens from groups 1 and 5. These, among the 11 groups in which grass pollen allergens are classified, are considered responsible for the most frequent and severe symptoms.