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B. G. Pummer, L. Atanasova, H. Bauer, J. Bernardi, I. Druzhinina, C. Müller, P. Schmitt-Kopplin, K. Whitmore, H. Grothe:
"Stress treatment of pollen and fungal spores - what are the impacts on IN activity?";
Talk: ESF-Workshop - Atmospheric Ice Nucleation, Wien (invited); 2013-04-06 - 2013-04-07; in: "Workshop - Atmospheric Ice Nucleation - Book of Abstracts", (2013).

Certain species of pollen and fungal spores have shown significant immersion IN activity in former laboratory studies [Kieft, Pouleur et al., Diehl et al., Pummer et al.]. In contrast to these habitual indoor conditions, bioaerosols in the atmosphere are exposed to numerous stresses, which adulterate them and so might have an impact on their IN activity. Atmospheric particles are exposed to reactive trace gases, extremes in temperature and humidity, high-energetic radiation and electricity (lightning).
We exposed pollen to NO2, O3 and UVA light as model stresses to determine their impact on IN activity. Furthermore, we investigated the pollen rupture and material release caused by soaking plus mechanical stress. Fungal strains from different origins were cultivated with and without occasional freezing events to determine the impact on IN activity. However, although the total protein content differed between frozen and non-frozen samples, the IN-activity remained nearly the same. This is in contrast to bacterial IN, which showed higher IN expression, when they were cultivated at lower temperatures [Gurian-Sherman and Lindow].
Additionally, we intensified our investigation on characterizing the pollen ice nuclei. Solid phase extraction with different columns proved to be a useful tool to confine the possibilities of the chemical nature of the ice nuclei. At last, dilution rows of pollen waters were prepared and investigated to determine the concentration dependency of the IN activity. The different datasets of the oil immersion and the LACIS measurements [Augustin et al.] perfectly match, if the concentration differences are considered.
Kieft TL: Appl. Env. Microbiol., 54, 1678-1681, 1988
Pouleur S et al.: Appl. Env. Microbiol. 58, 2960-2964, 1992
Diehl K et al.: Atmos. Res., 61, 125-133, 2002
Pummer BG et al.: Atmos. Chem. Phys., 12, 2541-2550, 2012
Gurian-Sherman D and Lindow SE: Cryobiology, 32, 129-138, 1995
Augustin S et al.: Atmos. Chem. Phys. Discuss., 12, 32911-32943, 2012

Ice Nucleation, Bioaerosols, Environmental Stress