engleski

Airborne fungi on the island Obonjan (Middle Adriatic, Croatia)

Fungi are ubiquitous microorganisms that have a great capacity to colonise many kinds of substrates including soils, plants and animal remains. Their spores constitute a major component of airspora. The airspora dispersion and concentration depend on numerous factors including ; time of day, seasonal climatic factors of particular region (temperature, humidity, wind, rainfall), type of vegetation, air pollution, agricultural, industrial and other human activities. Members of Cladosporium, Alternaria, Penicillum and Aspergillus are the most abundant allergenic airborne fungi, permanently present in many aeromycological surveys. Exposure to airborne fungi is known to induce numerous human respiratory diseases and allergies. The aim of the research was to determine the frequency of airborne fungi on the island Obonjan, and to examine toxigenic potential of Aspergillus species which were isolated in the middle and eastern part of the island. The samples (N=16) were taken on the three different locations on island Obonjan (eastern and western part, and in the middle of island), using Petri plate gravitational method in 1 hour with 2% Sabouraud-glucose agar plates supplemented with 50 mg/L of streptomycin and 20.000 I.U. of penicillin. After the sampling, the plates were incubated at 25º C during 5 days, and colony-forming units of moulds were counted (CFU/plate/h). The isolated aspergilla were, further, investigated on production of mycotoxins (aflatoxins, sterigmatocystin, ochratoxin A) by transplanting them to the YES broth. After 10 days of incubation at 25º C, the mycotoxins were extracted by multytoxin method and detected by thin layer chromatography (1). Average concentration of airborne fungi on the island was 3.4 CFU/plate/h, which is significantly lower than concentrations previously measured in continental parts of Croatia (44 CFU/plate/h) (2). Species of Pullularia (37.5 %), Aspergillus (31.2 %), Penicillium (25.0 %), Cladosporium (18.7 %), and Alternaria (6.2 %) were the most frequently found. In further, nine strains of A. flavus were tested on the production of aflatoxins (B1, B2, G1, G2) and sterigmatocystin, and three strains of A. niger were analysed on the production of ochratoxin A. One strain of A. flavus produced AFB1 in traces (under the detection limit). Positive control of A. flavus NRRL 3251 produced 16.0  g/mL of AFB1. Other strains did not produce any of analysed mycotoxins. Higher frequency of airborne aspergilla was probably influenced by the wind and waste deposition (in addition, decay of bananas and other imported fruit) in southern of the island. The presence of great number of Pinus sp. and aerosol of essential oils can be one of the reasons for reduced airspora viability and probably suppress production of aflatoxin.

Airborne fungi; Cladosporium; Alternaria; Aspergillus

Ovaj rad su izradili studenti smjera Medicinske biokemije Farmaceutsko-biokemijskog fakulteta u sklopu ljetne škole "8th CROPBSA Interdisciplinary International Summer School" koja se održavala na otoku Obonjanu (8-14.08.2005). Na kongresu CEFORM rad je nagrađen kao najbolja poster prezentacija u mikološkoj sekciji. Studenti su rad izradili pod vodstvom prof. dr. sc. Stjepana Pepeljnjaka i dr. sc. Maje Šegvić Klarić