Aspergillus flavus (A. flavus) and Aspergillus fumigatus (A. fumigatus) are the main fungi that cause stonebrood in honey bees. Additionally, these fungi cause the declines of honey bee population and the economic loss in the beekeeping industry. In this study, the efficacy of a disinfectant, composed to chlorine dioxide (10%, w/v) and quaternary ammonium compound (12.5%, w/v), was evaluated against A. flavus and A. fumigatus. A fungicidal efficacy test by broth dilution method was used to determine the lowest effective dilution of the disinfectant following exposure to test fungi for 30 min at 4°C. The disinfectant and test fungi were diluted with low and high organic matter (OM) suspension according to treatment condition. On low OM condition, the fungicidal activity of the disinfectant against A. flavus and A. fumigatus was all 2.0 fold dilutions. On high OM condition, the fungicidal activity of the disinfectant against A. flavus and A. fumigatus was all 1.25 fold dilutions. The recommended dilution ratio of the disinfectant in low and high OM was 1.6 and 1.0 fold dilution, respectively. As the disinfectant possesses fungicidal efficacy against A. flavus and A. fumigatus, the disinfectant can be used to prevent the stonebrood in honey bees.

Aspergillus fumigatus IFO 5840이 생산하는 cytosine deaminase에 미치는 cytosine analogue의 영향을 조사하여 다음의 결과를 얻었다. 1.Cytosine deaminase의 강한 저해를 나타내는 cytosine analogue는 2-thiouracil, 2-thiocytosine, 2-mercaptopyrimidine, 및 6-azacytosine이었다. 2.본 효소에 대한 2-thiocytosine 및 6-azacytosine의 50% 효소활성 저해농도(HIC)는 각각 0.80mM 과 1.15mM 이었다. 3. 2-thiocytosine은 일정한 수준에서 본 효소의 반응을 정지시키는 반면, 6-azacytosine은 반응시간에 비례하여 일정한 비율로 저해하였다. 4. 2-thiocytosine과 6-azacytosine은 cytosine이나 5-fluorocytosine의 기질 종류에 관계없이 본 효소의 저해제로 작용하였으며 2-thiocytosine이 6-azacytosine보다 약 2배 정도의 높은 저해를 나타내었다. 5. cytosine을 기질로 하였을 경우, 2-thiocytosine과 6-azacytosine에 의해 경쟁적 저해를 나타내며 이들에 대한 K_i값은 각각 4.5 × 10^-4M 과 1.756 × 10^-3M 이었으며 cytosine, 2-thiocytosine 및 6-azacytosine에 대한 Hill 게수(Hn)는 각각 1.80, 1.81, 2.45로 나타났다.

Endophytic Aspergillus Fumigatus sp. LH02, isolated from the roots of soybean and indentified through phylogenetic analysis of 18S rDNA sequence, was found stimulatory to the growth of Waito-C rice seedlings among 13 other endophytic strains screened. In growth hormone analysis, pure culture of fungal isolate produced three gibberellins viz GA4, GA9 and GA12. To know the role and effect on soybean in endophytic association (EA) and non-endophytic association (NEA) under salt stress (70 and 140mM), experiment was carried out at growth chamber using complete randomized block design. The results elaborated that the EA has significantly increased the shoot length, shoot and root fresh and dry weights, chlorophyll content, photosynthesis rate and leaf area of the plants with and without salt stress compared to control. Field emission scanning electron microscope analysis of root's surface showed that EA plants were extensively colnized by Aspergillus fumigatus LH02 under high salanity. In phytohormonal anlysis, ABA contents in EA and NEA were almost similar. Howere, when plants were exposed th salt stress, ABA levels were found significantly low in EA compared to NEA plant. In isoflavone content analysis, aglycones, malonyl, acetyl and glucosides isoflavones (total 11 compounds) were analyzed for each treatment through extensive HPLC andalysis. The quantities of isoflavone were found higher in EA plant's leaves with and without salt stress compared to NEA plant leaves. In conclusion, such endophytic association can be beneficial to explore ways to improve crop production under stressful conditions.