Comparison of anti-Aspergillus activity of Origanum vulgare L. essential oil and commercial biocide based on silver ions and hydrogen peroxide

The antifungal activities of Origanum vulgare essential oil (EO) and of a biocide based on silver and hydrogen peroxide (Sanosil S003) against seven Aspergillus species isolated from different substrata (stone, brick, silk and paper) of cultural heritage objects in Serbia were evaluated. Microdilution, agar dilution and microatmosphere methods were used to determine minimal fungistatic and minimal fungicidal concentrations (MIC and MFC), and light microscopy to determine structural abnormalities. MIC and MFC values for O. vulgare EO ranged from 0.2 to 5 mg mL−1 and for Sanosil S003 from 5 to 250 mg mL−1. Aspergillus sp. sect. fumigati was the most susceptible isolate, where MIC and MFC values were achieved at 0.5 mg mL−1 for O. vulgare EO, while MIC and MFC values for Sanosil S003 were achieved at 5 and 10 mg mL−1, respectively. Morpho-physiological changes were documented in all isolates, including lack of sporulation, depigmentation of conidiogenous apparatus and conidia, and presence of aberrant fungal structures. O. vulgare EO exhibited stronger anti-Aspergillus activity than Sanosil S003, as demonstrated by the higher MIC and MFC values and fewer morpho-physiological changes observed in the tested Sanosil S003 concentrations. O. vulgare EO could be an excellent alternative to commercial biocides, with high potential in the field of cultural heritage conservation

Phyllosphere mycobiota of Eucalyptus camaldulensis Dehnh. and E. globulus Labill.

Diversity of phyllosphere microfungi of two Eucalypti species (E. camaldulensis and E. globulus) was investigated using moist chamber method. A total of 19 different taxa of phyllosphere microfungal community were identified in leaves and seed bearing capsules. Aspergillus niger was the most frequent isolate in both investigated Eucalyptus species along with Alternaria alternata and Penicillium spp. Saprotrophic species occurred more frequently in Eucalypti phyllosphere compared to plant pathogens. Epiphytes were quantitatively prevalent. Microscopic analyses of E. globulus phylloplane microfungal community revealed potential inhibitory effect of Trichoderma viride against Eucalypti pathogenic species Seimatosporium eucalypti which formed aberrant, collapsed conidia. The study of phyllosphere mycobiota is of significant importance, considering that numerous leaf inhabiting fungi are in complex interactions with each other and their host plant. [Projekat Ministarstva nauke Republike Srbije, br. 173032

Succeptibility of some fungi to Boswellia carteri Birdw. essential oil

Antifungal activity of commercial sample of Boswellia carteri essential oil against selected micromycetes was evaluated in vitro using a microatmosphere method. When compared with biocide Sanosil S003, used as positive control, the tested essential oil showed moderate antifungal activity. The most susceptible fungi to oil treatment were Stachybotrys chartarum and Trichotecium roseum. For both fungi, mycelia growth inhibition of 85% was recorded at oil concentration of 100 μL mL-1. The tested essential oil caused inhibition of S. chartarum sporulation as well as depigmentation of conidiа, which is very significant since melanin contributes to virulence, survival and endurance of pathogenic fungi spores. Aspergillus niger was the least susceptible isolate to essential oil treatment. Mycelial growth of this fungus was not inhibited by any oil concentrations used in the experiment

Assessment of diesel fuel uptake by fungi isolated from petroleum contaminated soil

The aim of this research was to isolate and identify the fungi from petroleum-contaminated soil, to test their ability to grow in the presence of diesel fuel and uptake it in solid and broth media. Among 16 isolated and identified filamentous fungi, six were tested to determine their growth on media enriched with diesel fuel as a sole carbon source. All tested isolates showed different degree of diesel fuel utilization. Colony diameter was measured, where the highest colony growth dynamics ratio was demonstrated for Penicillium sp. (74.16%) and Cladosporium sp. (71.43%), and the lowest for Absidia spinosa (23.15%). Results of dry mass measurements demonstrated the highest potential of A. strictum (71.43%) to utilize diesel fuel in broth medium. All other tested isolates showed insignificant dry mass production ratio values. The highest utilization degree was documented for A. strictum (60.28 %) and the lowest for Penicillium sp. (25.18%). [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 173032

First case report on pathogenic fungus Fonsecaea sp. Negroni from skin of Pelophylax kl. esculentus L. in Serbia

Non-harmful adhesive tape method was applied directly on the skin surface of edible frog (Pelophylax kl. esculentus), captured in vernal ponds on the locality “Stevanove ravnice” within the Special Nature Reserve „Deliblatska peščara“, in order to detect fungal dwellers of frogs’ skin. Light microscopy analyses of Lactophenol Cotton Blue mounted adhesive tape samples taken from frog’s ventrum revealed the presence of melanized septate hyphae, branched conidiophores with chains of single-celled ovoid conidia, arising directly from the skin, which corresponds to morphological features of dematiaceous hyphomycete - Fonsecaea sp. Since members of genus Fonsecaea are frequently cited as causative agents of chromomycosis in amphibians, as well as human phaeohyphomycosis, world­wide, it is of great significance to study the presence of this fungal pathogen on amphibians in Serbia in order to make the basic reference data of the incidence of these pathogens in this region. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 173032