Eğitim Bilimleri Fakültesi / Faculty of Education
Permanent URI for this collectionhttps://hdl.handle.net/11727/2116
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Item Are the Photosynthetic Performance Indexes and the Drought Factor Index Satisfactory Selection Criterion for Stress?(2015) Cicek, Nuran; Arslan, Ozlem; Culha-Erdal, Sekure; Eyidogan, Fusun; Ekmekci, Yasemin; ACA-9644-2022This study was conducted to assess the drought stress and the recovery responses of twenty one chickpea cultivars (Cicer arietinum L.) grown in Turkey. 20-day-old seedlings were subjected to mild drought conditions for 7 days, recovery period of 3 days followed. Then a moderate stress period of 10 days was applied, followed by recovery period of 4 days. Finally, severe stress period of 13 days was applied, followed by recovery period of 5 days. Drought stress treatments were observed to have an adverse effect on photosynthetic efficiency, but also malondialdehyde, total chlorophyll (app. half of cultivars) and carotenoid contents of leaf tissue have increased when compared with their controls. 21 chickpea cultivars were classified into four groups; highly tolerant, tolerant, less tolerant and sensitive, according to the drought factor index (DFI), the values calculated by photosynthetic performance index (PItotal). Only four cultivars recovered from severe drought stress conditions. Aziziye and Diyar 95 cultivars may be suggested to be cultivated in drought-prone areas. In general, the present results indicate that: 1. PItotal and DFI are very satisfactory selection criterion for drought stress. 2. The recovery processes of plants exposed to environmental constraints should be investigated to make the right selection.Item Development of A Paper-Type Tyrosinase Biosensor for Detection of Phenolic Compounds(2015) Senyurt, Ozge; Eyidogan, Fusun; Yilmaz, Remziye; Oz, M. Tufan; Ozalp, V. Cengiz; Arica, Yakup; Oktem, Huseyin A.; 0000-0002-0042-2671; 0000-0002-7659-5990; 0000-0003-2041-1205; 24847915; H-1640-2013; B-2940-2009; ACA-9644-2022; M-8310-2018A low-cost, portable, and disposable paper-type tyrosinase biosensor was developed for determination of phenolic compounds, using a paper-strip absorption method. Tyrosinase and a chromophore (3-methyl-2-benzothiazolinone hydrazone) were immobilized on paper strips to manufacture the biosensor, which was tested on a nontoxic substrate (l-dopamine). The biosensor was responsive to phenolic compounds such as 4-chlorophenol, catechol, m-cresol, and p-cresol. The sensor showed stability for 70days. The developed biosensor can be used for remote on-site qualitative monitoring of phenolic compounds in wastewater samples.Item Does Sublethal Temperature Treatment Provide Any Tolerance in Tetraploid Wild and Durum Wheat Seedlings Exposed to Lethal Heat Stress?(2016) Eyidogan, Fusun; Terzioglu, Serpil; Ekmekci, Yasemin; ACA-9644-2022In this study, the effects of sublethal heat application before lethal heat treatment on thermotolerance mechanisms of tetraploid two wild wheats (Aegilops biuncialis and Aegilops cylindrica), and two durum wheats (Triticum turgidum L. cv. Kiziltan-91 and Harran-95) have been investigated. Eight-day-old seedlings were exposed sublethal heat pretreatment followed by lethal heat treatment [39 +/- 1 degrees C for 24h afterwards 50 +/- 1 degrees C for 1 h (T1)] and lethal heat treatment [50 +/- degrees C for 1 h (T2)]. When plants exposed to direct lethal temperature (T2), seedling lengths were significantly reduced in all genotypes. The sub-lethal treatment enabled the seedlings to tolerate the lethal effects of heat stress with respect to seedling length but this effect was not observed in Kiziltan-91 cultivar. T1 and T2 applications caused a decrease in relative water content in leaves of all genotypes. Total chlorophyll and carotenoid contents of tetraploid wild species were significantly decreased after all heat treatments. The sub-lethal heat pretreatment caused an accumulation of total chlorophyll and carotenoid contents in only Kiziltan-91 cultivar. Ae. cylindrica was found to be sensitive to heat but its degree of protection was higher than other genotypes. This tetraploid wild genotype probably withstands heat with better upregulating protective mechanisms.Item DNA Aptamer-Based Colorimetric Detection Platform for Salmonella Enteritidis(2017) Bayrac, Ceren; Eyidogan, Fusun; Oktem, Huseyin Avni; 28646719; ACA-9644-2022Food safety is a major issue to protect public health and a key challenge is to find detection methods for identification of hazards in food. Food borne infections affects millions of people each year and among pathogens, Salmonella Enteritidis is most widely found bacteria causing food borne diseases. Therefore, simple, rapid, and specific detection methods are needed for food safety. In this study, we demonstrated the selection of DNA aptamers with high affinity and specificity against S. Enteritidis via Cell Systematic Evolution of Ligands by Exponential Enrichment (Cell-SELEX) and development of sandwich type aptamer-based colorimetric platforms for its detection. Two highly specific aptamers, crn-1 and crn-2, were developed through 12 rounds of selection with K-d of 0.971 mu M and 0.309 mu M, respectively. Both aptamers were used to construct sandwich type capillary detection platforms. With the detection limit of 103 CFU/mL, crn-1 and crn-2 based platforms detected target bacteria specifically based on color change. This platform is also suitable for detection of S. Enteritidis in complex food matrix. Thus, this is the first to demonstrate use of Salmonella aptamers for development of the colorimetric aptamer-based detection platform in its identification and detection with naked eye in point-of-care.Item Physiological, Biochemical, and Transcriptomic Responses to Boron Toxicity in Leaf and Root Tissues of Contrasting Wheat Cultivars(2017) Kayihan, Ceyhun; Oz, Mehmet Tufan; Eyidogan, Fusun; Yucel, Meral; Oktem, Huseyin Avni; ACA-9644-2022In this study, we examined physiological, biochemical, and transcriptomic responses to toxic boron (B) treatment in leaves and roots of two wheat cultivars in order to gain better insight into B response or tolerance mechanisms. Delayed development and reduced vigor caused by high B were not observed in leaves and roots of both cultivars. Length, wet weight, and dry weight were not markedly changed under B toxicity. In leaves, when compared to control, 995 and 892 genes were significantly expressed at least twofold under B toxicity in Atay and Bolal, respectively. In roots, expressions of 1248 and 957 genes were responsive to B toxicity in Atay and Bolal, respectively. In leaf and root tissues, B toxicity induced more genes related to protein degradation in Atay than those in Bolal. These differences in transcriptome were attributed to higher B accumulation in the sensitive cultivar which required high level of metabolic adjustment. B toxicity stress did not cause any significant change in photosynthetic activity and contents of proline and glycine betaine in both cultivars. Coordinately, we did not find any differentially expressed genes required for proline and glycine betaine metabolisms. Genes related to hormone signaling, kinases, transcription factors such as WRKY and MYB, and key enzymes in reactive oxygen species (ROS) scavenging mechanisms were differentially affected by B toxicity in both cultivars. Among commonly regulated genes in Atay and Bolal, glutathione S-transferase (GST) and NIP4;1 (nodulin-26-like intrinsic proteins) genes stand out as prominent actors in B stress response.Item Comparative physiological and proteomic analysis of cultivated and wild safflower response to drought stress and re-watering(2021) Culha Erdal, Sekure; Eyidogan, Fusun; Ekmekci, Yasemin; 33707869Drought is one of the major environmental stress that adversely affect the growth and development of oil seed plant, safflower. There is a limited knowledge on proteomic responses to support physiological, biochemical changes in how safflowers can regulate growth and metabolism under drought conditions and followed by re-watering. The changes in morphological, physiological, biochemical and proteomics of safflower genotypes (Carthamus tinctorius L.; Remzibey-05 and Linas, tolerant and sensitive cultivars, respectively, and C. oxyacantha M. Bieb., wild type) after exposure to drought and followed by re-watering have been examined. Drought negatively affected the shoot weight, water content, chlorophyll fluorescence, and biochemical parameters, including photosynthetic pigment, proline, MDA, and H2O2 contents and antioxidant enzyme activities in all genotypes, while the re-watering period allowed Remzibey-05 to recover, and it even provided the wild type completely recovered (approximately 100%). A total of 72 protein spots were observed as differently accumulated under treatments. The identified proteins were mainly involved in photosynthesis and carbohydrate, protein, defense, and energy metabolisms. Protein accumulation related to these metabolisms in Remzibey-05 were decreased under drought, while increased following re-watering. However, sensitive cultivar, Linas, could not exhibit an effective performance under drought and recovery when compared with other safflower genotypes.Item Generating salt-tolerant Nicotiana tabacum and identification of stress-responsive miRNAs in transgenics(2015) Aysin, Ferhunde; Erson-Bensan, Ayse Elif; Eyidogan, Fusun; Oktem, Huseyin AvniIdentification of vacuolar Na+/H+ antiporters facilitates the basis of salt stress tolerance mechanisms. Na+ accumulation into the vacuole is crucial for the avoidance of cytoplasmic Na+ toxicity. In this study, we show that the introduction of AtNHX1 into tobacco generated more tolerant plants when compared to wild-type plants. Transgenic tobacco plants exhibited higher germination rates in the presence of increasing salt concentrations compared to wild-type plants. In addition, proline levels were higher under salt stress conditions in both the shoots and the roots of transgenics compared to wild-type plants. Increase in malondialdehyde production during lipid peroxidation by salinity was lower in transgenic plants compared to the controls. Being important and newly discovered determiners of plant stress responses, microRNAs (miRNAs) are noncoding small RNAs and essential indicators of plant stress response mechanisms. For further identification of stress responses, the expression levels of growth and abiotic stress-related miRNAs (miR319a, miR319b, miR159b, miR398a, and miR398b) were quantified. miR319a, miR319b, and miR159b expression levels were higher in wildtype plants, and miR319a and miR159b expression was restored in transgenic plants. There was a slight decrease in the expression levels of miR398a and miR398b of wild-type plants. However, the recovery of the miR398a and miR398b expressions was especially significant in transgenic plants. Furthermore, an investigation of miRNAs in transgenic plants can help to understand the stress tolerance mechanisms of the plants.