Phenolic acid and flavonoid diversity in four Eucalyptus species

Fazilet Özlem Albayrak | Yüksel Keleş

The economic importance of Eucalyptus trees is due to their rapid growth and high biomass productivity, as well as the beneficial chemical compounds found in their various tissues. Eucalyptus cultivation is common in the southern part of Turkey, especially in the coastal areas of the Mediterranean. In this study, phenolic acids and flavonoids were analyzed in methanol extracts leaf tissues of four eucalyptus species by HPLC. Fifteen different phenolic compounds were determined in the leaf tissues of the four Eucalyptus species examined. The highest total phenolic amounts were found in E. botryoides (160.56 mg g-1DW), followed by E. tereticornis (66.47 mg g⁻¹ DW) and E. citriodora (64.02 mg g⁻¹ DW). Twelve different compounds were determined in E. botryoides and E. citriodora species, 10 in...

Responses of antioxidant defense system of Helianthus annuus to abscisic acid treatment under drought and waterlogging.

Yüksel Keleş, Serpil Ünyayar

The effect of abscisic acid (ABA) treatment on growth pigments and antioxidant defense system were in vestigated in seedlings of Helianthus annuus (cvs. Nantio F1 and Özde mirbey) subjected to drought and waterlogging stress. In addition, seedlings were sprayed with 10 µM ABA three times every other day. Reltive growth rate (RGR) was significantly reduced in both genotypes under drought stress, however, this growth inhibition was less in ABA-treated plants. Total chlorophyll content increased by drought stress in both gentypes. Ascorbate was not influenced by drought, while α-tocopherol in creased in cv. Nantio F1. Ascorbate and α-tocopherol in creased with drought stress in cv. Özdemirbey. ABA treat ment de creased ascorbate and ß-carotene contents while it increased α-tocopherol and xan...

A highly efficient catalyst consisting of Ni and S double-doped reduced graphene modified with ZnO nanoparticles for hydrogen peroxide electroreduction

Sedef Kaplan A, Rukan Suna Karatekin A

n this study, we prepared a novel electrocatalyst based on S doped reduced graphene layer modified with Ni and ZnO nanoparticles. The catalyst materials were characterized by X-ray Powder Diffraction (XRD), Raman spectroscopy, UV–vis spectroscopy, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), and mapping. Because of the synergistic effect between three materials (S, Ni, and ZnO), the new electrocatalyst finally formed with a large electroactive surface area. Through the measurement, it was concluded that this surface includes large active sites which can effectively improve the electron transfer rate. The electrocatalytic activity of Ni-ZnO@s-rGO toward H2O2 reduction was examined via some measurements such as CV, I-t measurement, and electrochemical imped...

FROM THE PERSPECTIVE OF PRESERVICE TEACHERS, THE ACCOMPLISHMENT LEVELS OF PRİMARY SCHOOL TEACHERS' EFFECTIVE TEACHER ATTITUDES IN SCIENCE LESSONS

Say, Fuat Serkan

Isolation of alcohol tolerant, osmotolerant and thermotolerant yeast strains and improvement of their alcohol tolerance by UV mutagenesis

Coral, Mutlu Nisa Ünaldı | Coral, Gökhan

In this study, the yeast strains were isolated from grapes by serial dilution technique to determine their alcohol-, sugar-and thermotolerance. 34 wild type yeast strains were isolated and alcohol-, sugar-and thermotolerance of these strains were determined. The maximum alcohol tolerance was found to be 9%(v/v) in yeast strain which is named Y2. Thermotolerance behavior of 6 strains were investigated. The strains were treated with UV light with intervals of 20, 30, 40 and 50 seconds. Selected resistant colonies were investigated for alcohol tolerance. It was found that alcohol tolerance increased from 9%(v/v) to 12%(v/v) on Y2 strain.

Isolation and characterization of lytic bacteriophages infecting fish pathogen Vibrio sp. strains

Talaş, Gizem | Coral, Gökhan | Coral, Mutlu Nisa Ünaldı | Yılmaz, Şakir Necat

In this study, bacteria were isolated from infected organs of sea bass (Dicentrarhus labrax) and identified as Vibrio sp. according to 16S rRNA analysis. Four bacteriophages were isolated from seawater samples collected from the coast of Mersin province in Turkey.Vibrio sp. strains were used as hosts for bacteriophage isolation. Bacteriophages inhibit the growth of their hosts; Vibrio sp. K12, Vibrio sp. K11, Vibrio sp. L8, Vibrio sp. L5 which are potential bacterial pathogen of sea bass. Bacteriophages were characterized by Restriction Analysis (RA) and Transmission Electron Microscopy (TEM). Restriction Analysis showed that genomes of bacteriophages LP8, KP12, LP5 and KP11 are double stranded DNAs and the sizes of these genomes are 73, 55, 44 and 23 kb respectively. Only three out of pha...

From The Perspective Of Preservice Teachers, The Accomplishment Levels Of Primary School Teachers' Effective Teacher Attitudes In Science Lessons

Say, Fuat Serkan

The aim of this study is to determine to what extent the Primary School Teachers can accomplish the effective teacher attitudes in science lessons. In this context, the observations of 83 primary school preservice teachers, who studied teaching practice course, have been used. In order to determine the accomplishment levels of primary school teachers’ effective teacher attitudes in science lessons, the preservice teachers have been asked to observe the primary school teachers in the schools they attend for the practice lessons and the accomplishment levels of science education teacher’seffective teacher attitudes has been determined via an observation form including 25 questions in total. Descriptive- survey research has been used in the study and the data have been analyzed through freque...

A COMPUTER GAME IMPLEMENTATION: INDIVIDUALLY OR IN A GROUP

Say, Fuat Serkan

A new record of potentially ichtyotoxic haptophyte species, Prymnesium parvum f. patelliferum, in the Sea of Marmara during a large-scale mucilage event in June 2021

Eker-Develi, Elif | Tekdal, Dilek

A non-calcifying haptophyte species, Prymnesium parvum f. patelliferum (Green, Hibberd & Pienaar) Larsen, is reported for the first time in the Sea of Marmara from the mucilage event on 11 June 2021. The species was identified with a light microscope and scanning electron microscope. In addition, the 18S rRNA gene was partially sequenced in this study. Amplified gDNA of the expected size was sequenced and analyzed via bioinformatics applications. Results of the analysis vigorously recommended that a 672 bp PCR product was component of a small subunit ribosomal RNA gene sequence. The isolate was named MEUE1, and the partial 18S rRNA sequence of MEUE1 was submitted to the NCBI database (accession number OQ740296). Sequence analysis of isolated culture also verified that it was P. parvum f. p...

The response of phytoplankton assemblages to environmental parameters in the Azad Dam Lake in the west of Iran.

Eker-Develi, Elif

Seasonal variations of phytoplankton abundance, species composition, and their interaction with environmental parameters were investigated in the Azad Dam Lake, in the West of Iran during 2015–2016. Sampling was conducted seasonally at five stations in the lake.Multivariate statistical analyses were carried out to define the abiotic variables influencing phytoplankton community composition. A total of 51 taxa of phytoplankton belonging to six phyla were identified. Bacillariophyta (diatoms) were most diverse with 22 taxa, comprised more than 90%of the total density. Despite the low Shannon–Wiener index (H0) diversity (0.10–1.54), pointing out the dominant density of Bacillariophyta resulted in high water quality. Statistical analysis showed seasonal phytoplankton assemblages differences i...

Marker pigments and carbon biomass of phytoplankton on the northeastern Mediterranean Sea coast

Eker-Develi, Elif

Marker pigments are used to determine taxonomic composition and biomass of microalgae in different oceanic regions. However, sometimes discrepancies are encountered between microscopy and marker pigment based approaches principally because of altering environmental factors influencing diversity of phytoplankton. In the present investigation, marker pigments from HPLC-CHEMTAX analysis concurrent with carbon biomass estimated by microscopy were investigated during 2015–2016 at weekly intervals in the eastern Mediterranean Sea coast. Counting nanoplankton (in particular non-calcifying haptophytes and prasinophytes) in live samples provided a better correlation between microscopy and pigment-based results than in fixed samples. Nanoplankton and picoplankton constituted ~56% of chlorophyll a ba...

Enhancing microalgae classification accuracy in marine ecosystems through convolutional neural networks and support vector machines

Eker Develi, Elif

Accurately classifying microalgae species is vital for monitoring marine ecosystems and managing the emergence of marine mucilage, which is crucial for monitoring mucilage phenomena in marine environments. Traditional methods have been inadequate due to time-consuming processes and the need for expert knowledge. The purpose of this article is to employ convolutional neural networks (CNNs) and support vector machines (SVMs) to improve classification accuracy and efficiency. By employing advanced computational techniques, including MobileNet and GoogleNet models, alongside SVM classification, the study demonstrates significant advancements over conventional identification methods. In the classification of a dataset consisting of 7820 images using four different SVM kernel functions, the line...

New records of haptophyte species from the Northeastern Mediterranean Sea for algal flora of Turkey.

Eker-Develi, Elif

Chrysochromulina alifera, Chrysochromulina lanceolata, Chrysochromulina parkeae, Haptolina cf. ericina, Umbellosphaera irregularis, Umbellosphaera tenuis, Umbilicosphaera foliosa, Syracosphaera molischii, Rhabdosphaera clavigera var stylifera and Ophiaster formosus were recorded for the first time along the Turkish coasts. Non-calcified haptophyte species Chrysochromulina alifera, C. lanceolata, C. parkeae and H. cf. ericina were observed in live samples since formaldehyde damages cells. Among them only C. alifera could be observed with SEM. Either SEM pictures or light microscope images of other species were presented. Although previously reported along Turkish coasts Syracosphaera pulchra was a coccolithophore species most frequently observed after Emiliania huxleyi in the study area. Sc...

The response of phytoplankton assemblages to environmental parameters in the Azad Dam Lake in the west of Iran.

Eker-Develi, Elif

Seasonal variations of phytoplankton abundance, species composition, and their interaction with environmental parameters were investigated in the Azad Dam Lake, in the West of Iran during 2015–2016. Sampling was conducted seasonally at five stations in the lake.Multivariate statistical analyses were carried out to define the abiotic variables influencing phytoplankton community composition. A total of 51 taxa of phytoplankton belonging to six phyla were identified. Bacillariophyta (diatoms) were most diverse with 22 taxa, comprised more than 90%of the total density. Despite the low Shannon–Wiener index (H0) diversity (0.10–1.54), pointing out the dominant density of Bacillariophyta resulted in high water quality. Statistical analysis showed seasonal phytoplankton assemblages differences i...

Antioxidant Capacity and Protein contents of Five Marine Microalgae

Yaman Halil | Eker-Develi Elif | Keles Yuksel

Antioxidant capacity, chlorophyll, marker pigment, and protein contents of four diatoms (Helicotheca tamesis, Haslea silbo, Nitzschia navis-varingica, and Asterionellopsis glacialis) and one cyanobacterium (Spirulina subsalsa) have been investigated. N. navis-varingica exhibited the highest chlorophyll a, fucoxanthin, ascorbic acid, and total antioxidant capacity (TAC) among the five species studied. Cupric-reducing antioxidant capacities of N. navis-varingica and H. silbo were higher than other species studied. A. glacialis exhibited the highest total superoxide dismutase (SOD) activity, H. silbo displayed the highest ascorbate peroxidase (APX) activity, and Spirulina subsalsa had the maximum phenolic and protein contents. Overall, compared to other studies in the literature, the...

Öğretmen Adaylarının Fen Bilimleri Eğitiminde Sanal Tasarım ve Üç Boyutlu Yazıcı Entegrasyonunun İncelenmesi

Koç, Adem | Coral, Mutlu Nisa Ünaldı

Fen bilimleri içeriğinde soyut kavramların oldukça yoğun olduğu bir öğrenme alanıdır. Konu ve kavramlara göre somutlaştırma işlemleri geleneksel laboratuvar ve fiziksel tasarım atölyelerinde gerçekleştirilebilse de, bu her zaman mümkün olamamakta ya da daha zor olabilmektedir. Bu sorunların üstesinden gelebilmek ve öğrenmede somutlaştırmanın önemine vurgu yapmak için, bu çalışma fen bilgisi öğretmen adaylarının katılımı ile soyut kavramların çoğunlukta olduğu Biyoloji III dersi kapsamında gerçekleştirilmiştir. Haftalık olarak ikişer ders saati şeklinde mühendislik tasarım süreci aşamalarına ve proje tabanlı öğrenme yöntemine göre gerçekleştirilen bu uygulamada üç boyutlu tasarım programı olan Tinkercad programı ve üç boyutlu yazıcı kullanılmıştır. Uygulama süreci başında öğretmen adayları ...