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  • Author or Editor: G. Oros x
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The relationship between the chemical structure of 54 1-aryl-2-(azol-1-yl)ethane derivatives and their antifungal activities, tested on 30 fungal species, have been examined. Among the 1-keto derivatives the compounds with a longer alkyl chain at the carbon atom adjacent to the azole ring as well as the chloro substituent on the benzene ring showed the highest antifungal activity, meanwhile, a shorter chain at the same carbon atom led to highest activity among the 1-chloro derivatives. To find the physico-chemical properties influencing the antifungal activity two series of molecular descriptors have been calculated applying the Dragon and the Sybyl VolSurf computer programs. The 3D structures of the compounds to these calculations were generated with the HYPERCHEM and the SYBYL molecular modeling programs. From the equation, obtained with stepwise regression using the antifungal activity data as dependent and the descriptors as independent variables, it is obvious that the factors describing the chemical structure itself (Dragon descriptors) have greater influence on the antifungal activity than the factors responsible for the passive penetration (VolSurf descriptors). The principal component analysis revealed that the 1-chloro derivatives, which are equipotent or more potent than the 10 reference azole fungicides, have at least two action modes.

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Okra seedlings tolerated soil-borne Rhizoctonia infection in strain dependent manner. No connection was revealed between pathogenicity of strains and their origin or taxonomic position. However, the okra proved to be susceptible to strains highly pathogenic to other host plants as well. R. zeae, a species new to European flora, was as aggressive to okra as the most potent R. solani strains. The effect of Rhizoctonia infection was more prominent on mass accumulation in hypocotyls than in cotyledons. The protein content and glutathione S-transferase activity increased in parallel with the evolution of disease syndrome. Metalaxyl, an acetanilide type systemic antioomycete fungicide induced glutathione S-transferase activity in cotyledons with 24 hours a phase, and this induction was more outstanding in symptomless seedlings grown in Rhizoctonia infested soil. It might be concluded, that the stress response of plants in tolerant host/parasite pair takes effect at higher level than in susceptible relationships.

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Authors: S. A. Deepak, G. Oros, S. Niranjan Raj, N. P. Shetty and H. S. Shetty

The effect of Melody Duo 66.75 wp was assayed on pearl millet downy mildew (PMDM). This novel fungicide, a combined preparation of iprovalicarb and propineb, controlled all developmental stages of Sclerospora graminicola. The protective effect of this preparation was due to iprovalicarb and was equipotent to metalaxyl-containing Apron 35 sd and Ridomil 72 MZ wp, whereas the eradicant activity of Melody Duo exceeded that of the two latters at comparative doses. Iprovalicarb was translocated acropetally and exhibited systemically an excellent curative activity. The downy mildewed pearl millet plants recovered after foliar treatments with the preparations. The exploitation of Melody Duo 66.75 wp is recommended against pearl millet downy mildew disease.

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Authors: L. Darnay, A. Tóth, B. Salamon, K. Papik, G. Oros, G. Jónás, K. Horti, K. Koncz and L. Friedrich

The aim of this study was to show how microbial transglutaminase (mTG) can be used as an effective texture-modifier for two popular Hungarian products: Trappist cheese and frankfurter. In both cases we investigated how components of these products, milkfat in cheese and phosphate in frankfurter, can be substituted by mTG. Therefore, Trappist cheese samples were produced from cow milk of 2.8%, 3.5%, and 5% milk fat. The effect of ripening was evaluated with Texture Profile Analysis (TPA) and sensory evaluation (scoring test, 10 trained panellists). Springiness and cohesiveness values were significantly higher by enzyme-treated semi-hard cheese samples at lower milk fat levels. Sensory evaluation showed that the enzyme-treatment led to higher scores by cheese samples made from cow milk of 3.5% and 5% milk fat. Frankfurter was made with 0.1%, 0.3%, 0.5%, and 0.7% tetrasodium pyrophosphate, and partly enzyme-treated with 0.2% commercial mTG enzyme preparation. Our results showed that mTG is able to significantly improve hardness and crunchiness by frankfurters made with 0.1% phosphate addition. Our sensory evaluation suggests that mTG and phosphate should be applied in combination in order to have a final product with recognisably more homogeneous texture.

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