Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 13Citation - Scopus: 16Exploration of Three Solanum Species for Improvement of Antioxidant Traits in Tomato(American Society for Horticultural Science, 2014) Top, Oğuz; Bar, Cantuğ; Ökmen, Bilal; Yüce Özer, Duygu; Rusçuklu, Dane; Tamer, Nilüfer; Frary, Anne; Doğanlar, SamiWild tomato species have been widely used for improvement of tomato disease resistance but have not been extensively explored for health-related traits. In this work, three interspecific populations derived from backcrosses between cultivated tomato and Solanum pimpinellifolium (LA1589), S. habrochaites (LA1223), and S. peruvianum (LA2172) were analyzed for water-soluble antioxidant activity, phenolic content, vitamin C content, and basic agronomic traits including fruit weight, shape, and color. The wild species accessions significantly exceeded S. lycopersicum for all three antioxidant traits with only one exception: vitamin C content in S. habrochaites LA1223. Several populations and traits showed transgressive segregation indicating that the backcross populations contained individuals with allele combinations that allowed antioxidant activity/content to exceed that of both parents. The S. habrochaites LA1223 population provided the best starting material for improvement of water-soluble antioxidant activity and phenolics content with 20% and 15% of the population, respectively, significantly exceeding the parental values for these traits. Moreover, the S. habrochaites population contained individuals that had nearly 2-fold more water-soluble antioxidant activity and phenolic content than cultivated tomato. The S. peruvianum LA2172 population was best for improvement of vitamin C content with 3-fold variation for the trait and individuals, which had twice as much vitamin C as cultivated tomato.Article Citation - WoS: 7Citation - Scopus: 6Water-Soluble Antioxidant Potential of Melon Lines Grown in Turkey(Taylor and Francis Ltd., 2012) Şelale, Hatice; Şığva, Hasan Özgür; Çelik, İbrahim; Doğanlar, Sami; Frary, AnneThe antioxidant potential of 42 melon (Cucumis melo) lines including six cultivars grown in Turkey was assessed by measuring total water-soluble antioxidant capacity, phenolic and vitamin C contents. The lines showed significant variability for all three antioxidant parameters with breeding lines having higher antioxidant capacity and phenolic content than some popular cultivars. Different types of melons also showed significantly different antioxidant potentials. Thus, galia and ananas types showed a higher mean antioxidant capacity and phenolic content than the other tested types (yuva, kislik, canary, and charentais). Correlation analysis between antioxidant parameters showed a significant correlation between water-soluble antioxidant capacity and phenolic content. © 2012 Copyright Taylor and Francis Group, LLC.Article Citation - WoS: 14Citation - Scopus: 23Water-Soluble Antioxidant Potential of Turkish Pepper Cultivars(American Society for Horticultural Science, 2008) Frary, Anne; Keçeli, Mehmet Ali; Ökmen, Bilal; Şığva, Hasan Özgür; Yemenicioğlu, Ahmet; Doğanlar, SamiIn this work, 29 pepper cultivars that represent the diversity of types and varieties grown in Turkey were analyzed for water-soluble antioxidant capacity and phenolic and vitamin C contents. In addition, 14 non-Turkish cultivars were tested for comparison. Significant diversity was observed in the different cultivars with the most variation (7.4-fold) seen for total antioxidant capacity, which ranged from 2.57 to 18.96 mmol Trolox/kg. Vitamin C content for the peppers ranged from 522 to 1631 mg·kg-1, a 3.1-fold difference, whereas total phenolic content for the pepper cultivars ranged from 607 to 2724 mg·kg-1, a 4.5-fold difference. When cultivars were grouped by morphology/ use, it was found that some types had significantly more variation and higher antioxidant activities than other types. Thus, for water-soluble antioxidant capacity, most variation was seen in long, blunt-ended Çarliston types, whereas long, pointed Sivri peppers had the highest mean capacity. Bell-shaped Dolmalik and Sivri peppers had the most variation for phenolic content, but fancy Süs and Sivri types had the highest means for this trait. Dolmalik types showed the most variation for vitamin C content, whereas Süs and Sivri peppers had the highest means for this character. All three parameters were significantly and positively correlated with the strongest correlation between total antioxidant capacity and phenolic content (r = 0.71). The presence of significant variation for antioxidant content in Turkish germplasm indicates that this material can be used for improvement and genetic mapping of nutritional content in pepper.Article Citation - WoS: 25Citation - Scopus: 23Structural Alteration of Cofactor Specificity in Corynebacterium 2,5-Diketo Acid Reductase(John Wiley and Sons Inc., 2004) Şanlı Mohamed, Gülşah; Banta, Scott; Anderson, Stephen; Blaber, MichaelCarynebacterium 2,5-Diketo-D-gluconic acid reductase (2,5-DKGR) catalyzes the reduction of 2,5-diketo-D-gluconic acid (2,5-DKG) to 2-Keto-L-gulonic acid (2-KLG). 2-KLG is an immediate precursor to L-ascorbic acid (vitamin C), and 2,5-DKGR is, therefore, an important enzyme in a novel industrial method for the production of vitamin C. 2,5-DKGR, as with most other members of the aldo-keto reductase (AKR) superfamily, exhibits a preference for NADPH compared to NADH as a cofactor in the stereo-specific reduction of substrate. The application of 2,5-DKGR in the industrial production of vitamin C would be greatly enhanced if NADH could be efficiently utilized as a cofactor. A mutant form of 2,5-DKGR has previously been identified that exhibits two orders of magnitude higher activity with NADH in comparison to the wild-type enzyme, while retaining a high level of activity with NADPH. We report here an X-ray crystal structure of the holo form of this mutant in complex with NADH cofactor, as well as thermodynamic stability data. By comparing the results to our previously reported X-ray structure of the holo form of wild-type 2,5-DKGR in complex with NADPH, the structural basis of the differential NAD(P)H selectivity of wild-type and mutant 2,5-DKGR enzymes has been identified.