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Öğe The ability of plant compost leachates to control black mold (Aspergillus niger) and to induce the accumulation of antifungal compounds in onion following seed treatment(Springer, 2006) Özer, N; Köycü, NDOnion seeds treated with leachates of composts prepared from alfalfa and sunflower stalks, at the dosages of 10% and 20% respectively, were inoculated with Aspergillus niger van Tieghem, causal agent of onion black mold disease. The ability of the leachates to induce the production of antifungal compounds and to control black mold were tested at seedling and set stages. Leachates from both composts were able to reduce disease incidence in sets, but not disease severity in onion seedlings. Extracts from treated seedlings and sets were fractionated by thin layer chromatography for their content of antifungal compounds. There were no significant differences between the fractions of alfalfa and sunflower compost leachates in the inhibition of the mycelium growth of A. niger, with the exception of one fraction. The presence of fluorescent pseudomonads and Pantoae agglomerans [synonym: Erwinia herbicola (Lohnis)] bacteria was determined in both leachates. The population of P. agglomerans was higher in the sunflower compost leachate compared to the alfalfa leachate. The tested strains of both bacteria were able to inhibit mycelium growth of the fungal pathogen in agar tests. This study suggests the possible role of beneficial bacteria in the induction of antifungal compounds in onion against A. niger during seedling and set stages.Öğe Dobutamine induced dynamic left ventricular outflow tract obstruction in patients with hypertrophic nonobstructive cardiomyopathy(Tohoku Univ Medical Press, 2002) Bolca, O; Özer, N; Eren, M; Dagdeviren, B; Norgaz, T; Akdemir, O; Tezel, TSome patients with hypertrophic nonobstructive cardiomyopathy (HNCM) suffer symptoms resembling those in obstructive type despite no left ventricular outflow tract (LVOT) gradient could be detected on resting echocardiography. To investigate the value of dobutamine stress echocardiography (DSE) in determining the dynamic left ventricular (LV) obstruction of patients with HNCM. The study was conducted on 31 patients who were diagnosed HNCM on resting echocardiography and 9 healthy person as a control group. Intraventricular flow acceleration of > 3 m/sec on DSE was accepted as dynamic LVOT obstruction. Group I and 2 included patients without and with dynamic LVOT obstruction, respectively. The occurrence of chest pain and dyspnea seen during DSE was more frequent in group 2 than group 1 and control group. The frequency of SAM was significantly higher (p < 0.05) and the septal angle was significantly lower (p < 0.001) in Group 2. The presence of SAM significantly correlated with the peak gradient (r = 0.61, p < 0.001). The septal angle had significant negative correlations with the peak gradient (r = .-0.77, p < 0.001) reached at DSE. The relative risk for peak gradient was highest when septal angle was less than or equal to 100degrees, with a sensitivity of 93%, specificity of 80%, positive predictive value of 82%, negative predictive value of 92%, and predictive accuracy of 87%. DSE is a reliable tool for the diagnosis of dynamic LV obstruction in patients with HNCM. The presence of SAM together with a low septal angle is highly predictive for the presence of a dynamic LVOT obstruction detected by DSE. (C) 2002 Tohoku University Medical Press.Öğe Effect of some organic amendments on onion bulb rot(Priel Publ, 2002) Özer, N; Köycü, ND; Mirik, M; Soran, H; Boyraz, DThe effect of soil amended with stalks of sunflower (Helianthus annuus L.), alfalfa (Medicago sativa L.) and Hungarian vetch (Vicia pannonica Crantz) on onion bulb rot caused by Fusarium oxysporum Schlecht. Esp. cepae (Hanz.) Snyder Hansen and Aspergillus niger v. Tieghem was tested in a soil naturally infested with the pathogens under field conditions. All treatments significantly reduced bulb rot incidence. The fungal and antibacterial populations varied among all of the amended tested soils. Heterotrophic fungal populations were more effective than heterotrophic bacterial populations in the suppression of disease. The highest population of fungal microflora was found in plots amended with sunflower stalks. The carbon-to-nitrogen ratio and available moisture content of amended soils have an indirect suppressive role on disease, by increasing the heterotrophic fungal population.Öğe Pectolytic isoenzymes by Fusarium oxysporum f. sp cepae and antifungal compounds in onion cultivars as a response to pathogen infection(Taylor & Francis Inc, 2003) Özer, N; Köycü, D; Chilosi, G; Pizzuolo, PH; Coskuntuna, A; Magro, PThe ability of two Fusarium oxysporum f. sp. cepae isolates, FOC6 and FOC8, to colonize onion seedlings, following seed inoculation of different cultivars, and the associated quantitative and qualitative polygalacturonase and pectin lyase production were analysed. Allium cepa 'Akgun 12' and 'Rossa Savonese' were shown to be resistant to both isolates. FOC6 and FOC8 differed in pectolytic enzyme production, isoenzyme patterns, and aggressiveness. The pectolytic enzyme production from FOC6 was generally lower than that of the more aggressive FOC8 isolate. Polygalacturonase activity was correlated with the disease development upon infection with FOC8. Germinating seeds of onion cultivars inoculated with both FOC6 and FOC8 were extracted and fractionated by thin-layer chromatography to determine their content of antifungal compounds. Extracts from resistant cultivars were characterized by the expression of peculiar antifungal fractions, which may be involved in resistance to the pathogen. Results from the present study suggest that, for each cultivar-isolate interaction, the disease severity during onion colonization by E oxysporum f. sp. cepae is the result of concomitant factors including: (i) the ability of F. oxysporum f. sp. cepae to produce different amounts of pectolytic enzymes, (ii) the production of distinctive pectolytic isoenzyme patterns, and (iii) the expression of distinct antifungal compounds.Öğe Resistance to fusarium basal rot of onion in greenhouse and field and associated expression of antifungal compounds(Springer, 2004) Özer, N; Köycü, ND; Chilosi, G; Magro, PGreenhouse and field evaluations of onion for resistance to Fusarium basal rot caused by Fusarium oxysporum f.sp. cepae were conducted on cultivars 'Akgun 12' and 'Rossa Savonese' previously described as resistant at the seedling stage. In the greenhouse experiments inoculations were carried out on seeds or soil; in the field experiments evaluation was performed on onion sets from plants grown in naturally infested soils. Akgun 12 and to a lesser extent Rossa Savonese were resistant to the disease at the bulb stage in all experiments. Results were also consistent with those obtained from a previous screening at the seedling stage. Onion sets were also extracted and fractionated by thin layer chromatography to determine their content of antifungal compounds. Extracts were characterized by the expression of distinct antifungal components, which may be involved in resistance to the pathogen.
