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| Titel |
Characterization of Acremonium and Isaria ice nuclei |
| VerfasserIn |
Bernhard G. Pummer, Ulrich Pöschl, Janine Fröhlich-Nowoisky |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250090137
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| Publikation (Nr.) |
 EGU/EGU2014-4355.pdf |
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| Zusammenfassung |
| Until recently, the only known fungal ice nuclei (IN) were a few exponents of lichen
mycobionts and Fusarium spp. [Kieft and Ruscetti 1990, Pouleur et al. 1992, Hasegawa et al.
1994, Tsumuki et al. 1995], as well as two strains of mold [Jayaweera and Flanagan 1982].
Other investigated species did not show any IN activity [Pouleur et al. 1992, Iannone et al.
2011, Pummer et al. 2013]. In the last few years, IN-activity has been discovered in some rust
and smut fungi [Morris et al. 2013, Haga et al. 2013], Acremonium implicatum (Acr.) and
Isaria farinosa (Isa.) [Huffman et al. 2013] and a handful of other airborne and soil fungi
[unpublished data].
We started characterizing the IN of Acr. and Isa.: Like other non-bacterial biological IN,
they can be easily separated from the cells in aqueous suspension, and keep their activity. The
IN-active aqueous suspensions were processed by filtration (5 μm, 0.1 μm, 300 kDa, 100
kDa) and exposure to heat (60°C) or guanidinium chloride (6 M). The IN activity of the
processed samples was measured by a freezing assay of droplets, as described by Pummer et
al. [2013]. Via the Vali formula, we calculated the amount of IN per gram of mycelium,
which is higher than 105 g-1.
The initial freezing temperature was -4°C for Isaria and -8°C for Acremonium IN. Both
were completely knocked out by 60°C or guanidinium chloride. The Acremonium IN are in a
mass range between 100 and 300 kDa. The Isaria IN seem to be either a bit larger, or more
attached to larger particles, since not all of them pass through the 300-kDa-filter. It is likely
that both of these new IN are proteinaceous like the IN of Fusarium spp. and lichen
mycobionts, which belong to the Ascomycota phylum. Since the Isaria IN show a high
onset freezing temperature and are rather large for single molecules, they might be
agglomerates.
Haga D.I. et al. (2013) J. Geophys. Res.: Atm. 118, 7260-7272
Hasegawa Y. et al. (1994) Biosci. Biotech. Biochem. 58, 2273-2274
Huffman A.J. et al. (2013) Atmos. Chem. Phys. 13, 6151-6164
Iannone R. et al. (2011) Atmos. Chem. Phys. 11, 1191-1201
Jayaweera K. and Flanagan P. (1982) Geophys. Res. Lett. 9, 94-97
Kieft T.L. and Ruscetti T. (1990) J. Bacteriol. 172, 3519-3523
Morris C.E. et al. (2013) Atmos. Chem. Phys. 13, 4223-4233
Pouleur S. et al. (1992) Appl. Environ. Microbiol. 58, 2960-2964
Pummer B. et al. (2013) Biogeosci. 10, 8083-8091
Tsumuki H. et al. (1995) Ann. Phytopathol. Soc. Jpn. 61, 334-339 |
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