IN VITRO EVALUATION OF THE EFFECTS OF ESSENTIAL OILS ON ASCOSPHAERA APIS, THE CAUSATIVE AGENT OF CHALKBROOD DISEASE

Honeybee diseases cause considerable expenses to beekeepers for cost of maintaining apiary’s inspection, colonies damaged or destroyed and drugs fed to prevent bee’s infections. One of them is Ascosphaera apis, a fungal pathogen causing Chalkbrood disease in honey bee larvae. Chalkbrood is most frequent during damp conditions. Infected larvae turn chalky white color, become hard, andthen  turn black. It can be regarded as “the most widespread infectious disease” and this has led toecon omic loss in apiculture. We aim to find an alternative approach by using essential oils frommedicinal plan ts in combating and controlling the disease. Therefore, current article compiled the effects of ten essential oils (citral, geraniol, citronelol, cinamaldehid, thymol, eucalyptus oil, lemongrass oil, fennel oil, clove oil and cedar oil) on Ascosphaera apis in the laboratory with an agar diffusion method and the method of serial dilutions in microdilution plate. A. apis strains wereisolated from the dead honey bee larvae and the fungal strains were identified using a lightmi croscopy. Various concentrations (0.08% - 10%) of the essential oils were experimented fordetermin ation of minimal fungistatic and also fungicide concentration. After incubation, the zones ofinhibition were deter mined with a magnifying lens. The minimal inhibitory concentration was in range of 0.3125% - 1.25% for tested essential oils (MIC- values), and the minimal fungicide concentration was in range of 1.25% - 5%. All tested substances shows in vitro fungistatic and fungicide potential and can be considered as potential alternative active agents for prevention and control of chalkbrood disease without the use of antibiotics

ANTIBACTERIAL ACTIVITIES OF SOME WILD MUSHROOM EXTRACTS AGAINST PSEUDOMONAS AERUGINOSA

Mushrooms synthesize a multitude of low-molecular-weight secondary metabolites that have an important role as communication signals, to defend mushroom habitat or to inhibit the growth of competitors. Investigations have shown that some of these metabolites have potent antimicrobial activity and could be beneficial for humans. In this study, antimicrobial potential of the extracts from six wild mushrooms: Amanita echinocephala, Russula medulata, Cerena unicolor, Hericium erinaceus, Ishnoderma benzoinum and Laetiporus sulphureus was evaluated against Gram-negative bacterium Pseudomonas aeruginosa. The antimicrobial activities of the methanolic mushroom extracts were investigated by the microdilution method. All the extracts that demonstrated inhibitory activities were further tested for bactericidal activity and minimum bactericidal concentration (MBC) values were determined. Antimicrobial activity was observed in all species included in the study, while the activities depended on the type and concentration of extract. The tested microorganism was more sensitive to the examined extracts from the polypore fungi (C. unicolor, H. erinaceus, I. benzoinum and L. sulphureus). The highest antibacterial activity was obtained in the extracts from polypores I. benzoinum and L. sulphureus (MBC=15.625 mg/mL). This study demonstrated that the analysed wild macrofungi have the potential to accumulate bioactive metabolites that possess antimicrobial activity

Biorazgradnja otpadne vode iz procesa proizvodnje maslinova ulja s pomoću Trichosporon cutaneum i Geotrichum candidum

Olive oil production generates large volumes of wastewater. These wastewaters are characterised by high chemical oxygen demand (COD), high content of microbial growth-inhibiting compounds such as phenolic compounds and tannins, and dark colour. The aim of this study was to investigate biodegradation of olive mill wastewater (OMW) by yeasts Trichosporon cutaneum and Geotrichum candidum. The yeast Trichosporon cutaneum was used because it has a high potential to biodegrade phenolic compounds and a wide range of toxic compounds. The yeast Geotrichum candidum was used to see how successful it is in biodegrading compounds that give the dark colour to the wastewater. Under aerobic conditions, Trichosporon cutaneum removed 88 % of COD and 64 % of phenolic compounds, while the dark colour remained. Geotrichum candidum grown in static conditions reduced COD and colour further by 77 % and 47 %, respectively. This investigation has shown that Trichosporon cutaneum under aerobic conditions and Geotrichum candidum under facultative anaerobic conditions could be used successfully in a two-step biodegradation process. Further investigation of OMW treatment by selected yeasts should contribute to better understanding of biodegradation and decolourisation and should include ecotoxicological evaluation of the treated OMW.Tijekom proizvodnje maslinova ulja nastaju velike količine otpadne vode. Karakterizira je visoka kemijska potrošnja kisika (KPK), visoka koncentracija sastojaka koji inhibiraju rast mikroorganizama, poput fenolnih spojeva i tanina i tamna boja. Cilj ovog rada je bio istražiti biorazgradnju otpadne vode iz procesa proizvodnje maslinova ulja s pomoću kvasaca Trichosporon cutaneum i Geotrichum candidum. Kvasac Trichosporon cutaneum u ovom je istraživanju uporabljen zbog svog visokog potencijala za biorazgradnju fenolnih i drugih toksičnih spojeva. Kvasac Geotrichum candidum uporabljen je kako bi se istražilo koliko je uspješan u biorazgradnji spojeva koji otpadnoj vodi daju tamnu boju. Pri aerobnim uvjetima Trichosporon cutaneum uklonio je 88 % KPK i 64 % fenolnih spojeva, dok tamna boja otpadne vode preostaje. Geotrichum candidum u statičkim je uvjetima smanjio KPK i boju za 77 %, odnosno 47 %. Ovo je istraživanje pokazalo da Trichosporon cutaneum pri aerobnim uvjetima i Geotrichum candidum pri fakultativno anaerobnim uvjetima mogu biti uspješno uporabljeni u dvostupanjskom procesu biorazgradnje. Daljnje istraživanje obrade otpadne vode iz procesa proizvodnje maslinova ulja s pomoću odabranih kvasaca trebalo bi pridonijeti boljem razumijevanju biorazgradnje i uklanjanju boje i trebalo bi biti provedeno zajedno sa ekotoksikološkim vrednovanjem obrađene otpadne vode

ISOLATION, CHARACTERIZATION AND FORMULATION OF ANTAGONISTIC BACTERIA AGAINST FUNGAL PLANT PATHOGENS

Concerns regarding food safety and the environment have led to reduced use ofagrochemicals and the development of sustainable agriculture. In this context,biological control of fungal plant pathogens can improve global food availability,one of the three pillars of food security, by reducing crop losses, particularly forlow-income farmers. Antagonistic bacteria are common soil inhabitants withpotential to be developed into biofungicides for the management of fungal plantpathogens. In this study, antagonistic bacterium was isolated from the commercialcompost from a Resen factory for compost and screened for its growth inhibition offungal pathogens in laboratory tests. The zone of inhibition (mm) was recorded bymeasuring the distance between the edges of the growing mycelium and theantagonistic bacterium. Five replications were maintained for each isolate. Basedon phenotypic characteristics, biochemical tests, and sequence analysis of 16SrRNA, the antagonistic bacterium was identified as Paenibacillus alvei (strain DZ-3). The bacterium suppressed the growth of all five tested fungal plant pathogens(Fusarium oxysporum, Rhizoctonia solani, Alternaria alternata, Botrytis cinereaand Plasmopara viticola) in in vitro conditions over. The survival of antagonisticbacterium in peat and talc formulations decreased time at room temperature, butthe populations remained above 108 CFU/g during the 180-day storage period. Thisstudy suggests that this bacterium can be developed and formulated asbiofungicides for minimizing the crop losses caused by fungal plant pathogens anddiseases caused by them

Impact of slavol microbiologial fertilizer on soil microorganisms during cauliflower (Brassica oleracea l.var. botrytis) growth

The experiment was conducted in order to determine the influence of the microbiological fertilizer Slavol on the number of microorganisms in the soil where cauliflower was grown in open field. It was used the variety Barselona F1 which was grown in Skopje region during three years (2011, 2012, 2013). The treatments were as follows: Ø control - without use of microbiological fertilizer, V1 - foliar treatment every 7 days with 0.1% solution of Slavol and V-2 - drip irrigation treatment every 2 days with 0,1% solution of Slavol. The total number of bacteria and the number of examined physiological groups of microorganisms in the rhizosphere (nitrogen fixing bacteria 10-4 , cellulolytic microorganisms 10-4 , yeasts 10-4 , nitrifying microorganisms 10-4 and molds 10-3 ) were counted. According to the results during three years examination highest average number of total bacteria was determined in the variant V-1 and V-2 in comparison to control and the soil before planting. The number of nitrogen fixing bacteria was from 4863519 in V-1 to 4923807 in V-2. The number of cellulolytic microorganisms was from 3288588 in V-1 to 3312114 in V-2. The number of yeasts was lower than control (3813208) and was from 3681506 in V-1 to 2585089 in V-2. The number of nitrifying microorganisms was very high in V-1 (7502534) and V-2 (7323212) in comparison to control (1331717) and fallow land. The number of molds was higher in V-1 (422192) and V-2 (352608) in comparison to control (340149) but lower in comparison to fallow land (474851)

EVALUATION OF BACTERICIDAL ACTIVITY OF SELECTED WILD MACROFUNGI EXTRACTS AGAINST Escherichia coli

The increasing failure of chemotherapeutics and antibiotic resistance exhibited by pathogenic microorganisms has led to the evaluating of novel sources for their antimicrobial potential. Nature is a generous source of compounds with antimicrobial activity. However, a large number of natural products with the potential to act as antimicrobials still await further investigation. In this study, antimicrobial activities of the extracts from four wild mushrooms: Amanita echinocephala, Russula medulata, Ishnoderma benzoinum and Laetiporus sulphureus were evaluated against Gram-negative bacterium Escherichia coli. The antimicrobial potential of the methanolic mushroom extracts was investigated by the microdilution method. Mild inhibitory activity was observed in 3 out of 4 mushroom species included in the study. The extracts were further tested for bactericidal activity and minimum bactericidal concentration (MBC) values were determined. The tested microorganism was most sensitive to the examined extracts of Laetiporus sulphureus (MBC=62.5 mg/mL). Even though the results revealed in this study may suggest that tested wild macrofungi extracts possess mild antimicrobial activity, their antimicrobial potential against other microorganisms need to be further elucidated