How do certain atmospheric aerosols affect Cu-binding organic ligands in the oligotrophic coastal sea surface microlayer?

It is still unclear how the chemical speciation of Cu in surface seawater is impacted by aerosols from various sources deposited on the sea surface, which is surprising, considering the environmental importance of Cu. Therefore, we used voltammetry to investigate Cu complexing capacity (CuCC) in the sea surface microlayer (SML) and in the underlying water (ULW) of the oligotrophic middle Adriatic Sea during February-July 2019. The focus was on the impacts of specific atmospheric processes such as open-fire biomass burning (BB), pollination season and Saharan dust intrusion. The presence of ligand class L2 (19.9-392.0, average 63.8, median 43.1) nM; log K2 (8.3-10.2, average 9.6, median 9.6) was observed in all samples, while ligand class L1 (40.5-76.1, average 53.6, median 48.9) nM; log K1 (10.3-11.1, average 10.6, median 10.5) was found in only 25% of SML samples. Throughout the period, the SML was enriched with organic ligands by a factor of up to 9.1 compared to the ULW, mainly due to the high sensitivity of the SML to specific atmospheric depositions. In addition, measurements with corresponding specific model aerosols were conducted to analyse their impacts on CuCC. Pollen directly affected CuCC in the SML by increasing the concentration of allochthonous ligands such as proteins. The deposition of BB aerosols rich in nutrients and trace metals stimulated the biological production of organic ligands, showing an indirect effect on CuCC delayed by up to two weeks. Finally, Saharan dust had a negligible impact on CuCC. This study illustrates the susceptibility of oligotrophic coastal area to the effects of pollen and open-fire BB aerosols in altering the Cu-binding organic ligands in the SML.

Molecular Study of Selected Taxonomically Critical Taxa of the Genus Iris L. from the Broader Alpine-Dinaric Area.

Some wild, morphologically diverse taxa of the genus Iris in the broad Alpine-Dinaric area have never been explored molecularly, and/or have ambiguous systematic status. The main aims of our research were to perform a molecular study of critical Iris taxa from that area (especially a narrow endemic accepted species I. adriatica, for which we also analysed genome size) and to explore the contribution of eight microsatellites and highly variable chloroplast DNA (ndhJ, rpoC1) markers to the understanding of the Iris taxa taxonomy and phylogeny. Both the microsatellite-based UPGMA and plastid markers-based maximum likelihood analysis discriminated three main clusters in the set of 32 analysed samples, which correspond well to the lower taxonomic categories of the genus, and support separate status of ambiguous regional taxa (e.g., I. sibirica subsp. erirrhiza, I. x croatica and I. x rotschildii). The first molecular data on I. adriatica revealed its genome size (2C = 12.639 ± 0.202 pg) and indicated the existence of ecotypes. For future molecular characterisation of the genus we recommend the utilisation of microsatellite markers supplemented with a combination of plastid markers.

Phenolic compounds of Iris adriatica and their antimycobacterial effects.

Little is known about the pharmacological activities of Iris adriatica (Iridaceae), a plant endemic to Dalmatia (Croatia). We therefore performed a bioassay-guided fractionation including high-performance counter current chromatography (HPCCC) and antibacterial tests using Mycobacterium smegmatis mc2 155. One obtained fraction was found to be antimycobacterially active with a MIC of 64 mg L-1. Furthermore, fractions were tested for resistance modulatory effects using ethidium bromide as substrate. We were able to identify the pure isoflavonic compounds irigenin and irilone and a fraction containing mainly benzophenone 2,4,6-trihydroxy-4-methoxy-benzophenone, responsible for the resistance-modulatory activity of this plant.

Comparative Analysis of Native Crocus Taxa as a Great Source of Flavonoids with High Antioxidant Activity.

Native Crocus taxa are abundant in regions with moderate and dry climate; however, their potential in the food industry has thus far been neglected. The objective of this study was to compare the quantitative and qualitative flavonoid content and antioxidant and cytotoxic activity in organs of several populations of Croatian native taxa and assess their potential for application in the food industry. The dominant flavonoids in the native Crocus taxa were kaempferol and quercetin. Tepals contained similar or higher concentrations of flavonoid-glycosides than other organs. Tepals from Cvv1 and Cvv2 populations contained more flavonoid-glycosides than the commonly used spice saffron (C. sativus stigmas). The FRAP antioxidant activity of Cvv1 and Cvv5 tepals was similar to that of standard Trolox. DPPH inhibition of Cvv1 and Cvv3 tepals was within the range of that recorded for saffron. Cvv1 tepals significantly reduced reactive oxygen species in the broadest concentration range (50-1000 µg/ml), and showed considerable antioxidant activity in the ABTS assay, equal to 82% of standard Trolox antioxidant activity. A significantly higher concentration of kaempferol-rutinoside was recorded in this than in other taxa. The flavonoid showed a very strong or strong correlation with antioxidant assays results, and a negative correlation with cellular reactive oxygen species concentration. We therefore presumed that kaempferol-rutinoside is one of the main antioxidant phenolics in Crocus tepals. None of the tested extracts showed cytotoxicity toward Caco-2 cells. The results revealed that Cvv tepals have potential as a food supplement and are a promising material for further food safety tests.

Invasive alien plants in Croatia as a threat to biodiversity of South-Eastern Europe: distributional patterns and range size.

During the analysis of alien and invasive flora of Europe, as a threat to biodiversity, data for Croatia were missing. The aim of our research was to analyse distributional patterns and range size of all invasive alien plants (64) for the state area (57,000 km(2)). They were detected on 49% of the state territory, averaging five taxa per 35 km(2). The greatest number of invasive plants (>30 per grid cell) was recorded in the major urban centres, increasing in the south-east direction and reflecting positive correlation with temperature and negative with altitude. The most endangered areas are in the Mediterranean region, especially on islands. The number of invasive plants increased with habitat diversity and almost 75% of all sites with invasive plants are located within a few habitats with direct anthropogenic influence. The results should provide a reliable regional and global basis for strategic planning regarding invasive alien plants management.

Aerobiology of sweet chestnut (Castanea sativa Mill.) in north-west Croatia.

The aims of the study were to analyse characteristics of the Castanea airborne pollen and to compare aeropalynological data obtained from two sampling stations in north-west Croatia. The study was conducted in Zagreb and Samobor during the 2003-2006 periods, using the seven-day volumetric samplers of the Hirst design. In both study areas, the seasons of chestnut pollination were similar and lasted from June to the end of July, which is comparable to other European cities. A general rule was noticed--the shorter the main pollen season, the higher the pollen peak concentration. Although the pollen season of Fagales pollen is prolonged to summer in the area of inland west-north Croatia due to the genus Castanea summer pollination, the number of days with pollen air concentration higher than 50 per m3 was low and was not likely to have any major effects in allergic individuals. Airborne pollen concentration of Castanea showed positive statistically significant correlation with air temperature and negative non-significant correlation with precipitation. Because of the non-significant differences between the two stations, for a possible long-term forecast model for Fagales airborne pollen for this part of north-west Croatia, aerobiological data obtained from only one station are sufficient.

Variation in ragweed (Ambrosia artemisiifolia L.) pollen concentration in central Croatia, 2002-2003.

The aim of the study was to determine the onset, duration and termination of the ragweed pollen season; intradiurnal, daily and monthly pollen variation, and possible differences in the occurrence and concentration of ragweed pollen according to sampling sites between 2002 and 2003. The study was conducted at three sampling sites in central Croatia over two pollen seasons (2002 and 2003) using the volumetric method of sampling (Hirst type sampler). In 2003, the ragweed pollen season was by 43 % longer and the percentage proportion of ragweed pollen by 3.4 % greater in comparison with 2002. The total ragweed pollen count and number of days with ragweed pollen concentration greater than 30 pollen grains per m (3) air showed a declining tendency from East to West in both seasons. The intradiurnal peak concentration occurred between 10.00-14.00. The air concentration of ragweed pollen decreased with temperature decline and precipitation. Results of the study provided useful information to individuals allergic to ragweed pollen thereby allowing them to adjust their outdoor activities to avoid contact with the allergen.

Atmospheric pollen season in Zagreb (Croatia) and its relationship with temperature and precipitation.

The number of individuals allergic to plant pollen has recently been on a constant increase, especially in large cities and industrial areas. Therefore, monitoring of airborne pollen types and concentrations during the pollen season is of the utmost medical importance. The research reported in this paper aims to determine the beginning, course and end of the pollen season for the plants in the City of Zagreb, to identify allergenic plants, and to assess the variation in airborne pollen concentration as a function of temperature and precipitation changes for the year 2002. A volumetric Hirst sampler was used for airborne pollen sampling. Qualitative and quantitative pollen analysis was performed under a light microscope (magnification x400). In the Zagreb area, 12 groups of highly allergenic plants (alder, hazel, cypress, birch, ash, hornbeam, grasses, elder, nettles, sweet chestnut, artemisia and ambrosia) were identified. Birch pollen predominated in spring, the highest concentrations being recorded in February and March. Grass pollen prevailed in May and June, and pollen of herbaceous plants of the genus Urtica (nettle) and of ambrosia in July, August and September. Air temperature was mostly higher or considerably higher than the annual average in those months, which resulted in a many days with high and very high airborne pollen concentrations. The exception was April, when these concentrations were lower because of high levels of precipitation. This also held for the first half of August and the second half of September. Pollen-sensitive individuals were at high risk from February till October because of the high airborne pollen concentrations, which only showed a transient decrease when the temperature fell or there was precipitation.

Analysis of airborne pollen concentrations in Zagreb, Croatia, 2002.

Employing the volumetric method by use of a Hirst sampler, a total of 71,286 pollen grains, as many as 94.20% of them allergenic, were recorded in the air samples from the city of Zagreb during the 2002 pollen season. Among identified pollen of 35 plant species/genera/families, 23 were allergenic: Taxus/Juniperus, Alnus sp., Fraxinus sp., Betula sp., Corylus sp., Poaceae, Urticaceae, Artemisia sp., Ambrosia sp., Carpinus sp., Castanea sp., Chenopodiaceae, Salix sp., Populus sp., Ulmus sp., Juglans sp., Quercus sp., Platanus sp., Fagus sp., Plantago sp., Pinus sp., Picea sp. and Abies sp. The pollen of these plants also cause the majority of pollinosis in Europe. Study results and the pollen calendar designed for the 2002 pollen season for the City of Zagreb provide useful data for allergologists to reach an accurate diagnosis. The calendar also provides timely information on airborne pollen types and air concentrations for individuals with pollen hypersensitivity, thus allowing them to adjust their daily activities so as to minimize their contact with allergens and improve their quality of life both at home and at work.