| Congresso Brasileiro de Microbiologia 2023 | Resumo: 1384-1 | ||||
Resumo:Bioaerosols are airborne biological particles (bacteria, fungi, viruses, pollen, fragments etc), and those primarily emitted by several surface processes are recognized as ice nucleators (IN) and to participate in the cloud formation. Therefore, by facilitating ice formation in clouds, IN play a critical role in the Earth's climate. Despite the importance of IN, the number of studies characterizing primary biological aerosol particles (PBAPs) in the hailstones is still scarce. The western region of southern Brazil, in particular the tri-border area with Paraguay and Argentina, is among the hotspots of hailstorms in the world. Big hailstones collected in that region (Lat: -24.178611°; Lon: -54.084096) are being analyzed to identify PBAPs. To analyze the samples, each hailstone was carefully washed with 400 mL, with sterile deionized water (resistivity 18.2 MΩ cm, ElgaŽ Purelab Maxima (England, UK) system) following the procedure suggested by Beal, et al. (2021). The melting process considered 5,0 mL for each layer until the complete melting, which the number of layers depending on the size of each sample (hailstone).
From each melted layer, 1,0 mL was destined for the cultivable bioaerosols. A total of 25 hailstones have been analyzed. In addition, a total of 59 artificial hailstones (blanks) and 7 samples of liquid water were prepared by using deionized water. Preliminary results indicate the presence of the following bacteria; Bacillus cereus; Priestia megaterium, Bacillus subtillis, Lysinobacillus fusiforme and the fungus Fusarium equiseti.
A negative result for bacteria was found for almost all artificial hailstones and water samples, indicating good control of the process and cleaning of samples. The presence of bacteria in the inner layer of hailstones suggests its ice-nucleating property.
Palavras-chave: bioaerosols, ice-nucleators, hailstorms | |||||