Türk Biyokimya Dergisi

Characterization of polyphenol oxidase during three ripening stages of an eggplant (Solanum melongena L.) fruit: a local type in northeast Anatolia [Patlıcan (Solanum melongena L.) meyvesinin polifenol oksidazının üç olgunlaşma safhası boyunca karakterizasyonu: Doğu Anadolu' da yerel bir tip] ABSTRACT Objective: A relatively new local type of eggplant, Solanum melongena L. 'Kadife' is widely consumed in Turkey because of its economic availability and good nutritional qualities. However, the high polyphenol content of eggplant renders it susceptible to unattractive oxidative browning catalyzed by polyphenol oxides (PPOs). Therefore, the main aim of this study was to characterize PPO in this eggplant cultivar at three stages of its development. Methods: In this study, we determined substrate specificity, optimum pH and temperature, and optimum substrate concentration of the partial purified eggplant fruits PPO during ripening. Results: L-DOPA was proved to be the preferred PPO substrate in all three stages of ripening. Optimum activity was observed at pH 7.0 for PPO in extracts of ripening and overly-ripe eggplant, while activity in extracts of immature eggplant exhibited a broad pH optimum between, pH 5.0 and 7.0. In general, at all ripening stages, PPO was most active at 30°C and was most sensitive to inhibition by sodium metabisulphite and ascorbic acid. The metal ions (Hg ÖZET Amaç: Kısmen yeni bir yerel tip patlıcan çeşidi Solanum melongena L. 'Kadife', ekonomik uygunluğu ve iyi besin kalitesinden dolayı Türkiye'de yaygın olarak tüketilir. Bununla birlikte, patlıcanın yüksek polifenol içeriği, bu meyveyi polifenol oksidaz (PFO) tarafından katalizlenen istenmeyen oksidatif esmerleşmeye karşı duyarlı kılar. Dolayısıyla, bu çalışmanın temel amacı, gelişiminin üç safhasında bu patlıcan kültivarındaki PFO'yu karakterize etmektir. Metod: Bu çalışmada, olgunlaşma boyunca patlıcan meyvelerinden elde edilen kısmi saflaştı-rılmış PFO'nun substrat özgünlüğünü, optimum pH ve sıcaklığını, ve optimum substrat konsantrasyonunu belirledik. Bulgular: Olgunlaşmanın her üç safhasında, L-DOPA'nın tercih edilen PFO substratı olduğu ortaya konuldu. Olgunlaşmamış patlıcan özütlerinde optimum pH 5.0 ile 7.0 arasında geniş bir aktivite gösterirken olgun ve aşırı olgun patlıcan özütlerindeki PFO aktivitesi için optimum pH'nın 7.0 olduğu gözlendi. Genel olarak, tüm olgunlaşma safhalarında, PFO, 30°C'de en aktiftir ve inhibitör olarak sodyum metabisülfit ve askorbik aside oldukça duyarlıdır. Materials and Methods Plant material The seeds belonging to the eggplant (Solanum melongena) were obtained from local growers, but they have not certificated yet

The persistence of misconceptions about the human blood circulatory system among students in different grade

Abstract: In this paper, it is aimed to investigate the persistence of misconceptions in the topic of the human blood circulatory system among students in different grade levels. For this reason, after discussions with biology educators, two tests consisting of open-ended questions were developed by the researcher and administered to students in four different grade levels. The first test was administered to 319 5th and 7th grade students in elementary school and the second one was administered to 400 1st and 4th year university students studying in the departments of elementary school teaching, science education and biology education. Data were analyzed using qualitative methods and a number of misconceptions were detected in different grade levels. According to the results of the study, the distributions of the percentages of students' misconceptions demonstrate a decreasing trend from elementary school students to university students without totally disappearing. The reason of this situation might be the persistence of misconceptions that are difficult to overcome. Due to their functionality, students continue to possess certain misconceptions. Hence, this characteristic of misconceptions should be considered while planning teaching activities in teacher education programs

An Analysis of Scores of Prospective Biology Teachers on the Factors of MSLQ

Abstract. The factors of learning strategies and motivation as components of self-regulation are determined well in MSLQ (Motivated Strategies for Learning Questionnaire) scale. The scale includes 15 factors. But, these 15 factors are not appropriate for practical use. In this study, a survey research was conducted with 112 prospective biology teachers by using MSLQ to analyze the factors. One-way ANOVAs and Pearson Product-Moment Correlation Coefficients were used for analysis. The results of ANOVAs showed that there were no statistically significant differences between mean scores of the participants at different grade levels on scales of MSLQ. In addition, the "task value", the "self-efficacy" and the "help seeking" subfactors were found to be the most dominant sub-factors of the whole scale. In the article, results of the study and limitations will be discussed

568 LONGHORNED BEETLES OF KIRIKKALE PROVINCE IN TURKEY (COLEOPTERA: CERAMBYCIDAE)

ABSTRACT: This work is the first attempt for entire longhorned beetles fauna of Kırıkkale. All known taxa from Kırıkkale province are given with new faunistical data in the present text. 31 species are new records for Kırıkkale province. Pedostrangalia verticalis (Germar, 1822) is also the first record for Central Anatolian Region of Turkey. Moreover, Phytoecia rufipes rufipes (Olivier, 1795) is also the first report for the northern half of Turkey

Türk Biyokimya Dergisi

ABSTRACT Objective: The aim of this study was to investigate the laccase production of Trametes versicolor under submerged fermentation condition. Then, dye decolorization by laccase was optimized using Box-Behnken methodology. Methods: The optimal culture conditions for producing high amount of laccase were determined using Taguchi methodology. The experiments were designed with five factors (glucose, yeast extract, CuSO 4 , inoculum size and pH) at three levels with orthogonal array layout of L27 (3 5 ). Then, the optimum conditions for high decolorization activity of Reactive Blue 49 by obtained crude laccase were also investigated using Box-Behnken methodology. Results: The optimum culture conditions for production of high amounts of laccase were detected as 2 g L -1 of glucose, 5 g L -1 of yeast extract, 2mM of CuSO 4 , 4% of inoculum amount and pH 5.5. Yeast extract was the most effective factor, followed by CuSO 4 , inoculum, glucose and pH. Under these conditions, predicted values were in a good agreement with the actual experimental one. The predicted results showed that the maximum of Reactive Blue 49 decolorization as 98% could be obtained under the optimum conditions of pH 2.95, initial dye concentration 55.6 mg L -1 , enzyme amount 0.76 mL and reaction time 46.91 min. The validity and practicability of this statistical optimization strategy was confirmed with the relation between predicted and experimental values. Conclusion: The results suggested that Taguchi method can be used in the optimization of laccase production process. Production of laccase by Trametes versicolor 2008001 can be effectively used for enzymatic decolorization according to the results of decolorization experiments in optimal levels. Key Words: Laccase, Taguchi Method, Box-Behnken Methodology, dye decolorization. Conflict of Interest: The authors declare no conflict of interest. Materials and Methods Microorganism, culture conditions and dye Trametes versicolor ATCC (200801) originally isolated and cultured by Dr. O Yesilada was used in this study. This fungus was subcultured on Malt Extract Agar (MA) plates of 30 °C and stored at 4 °C. Laccase production of T. versicolor was tested under agitated culture conditions. To this end, firstly this fungus was cultured at 30 ˚C on slant MA for one week. Then, mycelial suspension was prepared and this suspension was inoculated into 250 mL Erlenmeyer flask containing 100 mL Potato Dextrose Broth (PDB). This culture was incubated at 30 °C and 150 rev min -1 for 4 days. After that, the culture was homogenized and determined culture of homogenized culture was transferred in 250 mL Erlenmeyer flasks with 100 mL Stock Basal Medium (SBM) that contain K 2 PO 4 : 0.2 g