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- MakaleAçık Erişim2024Geochemical and petrological features of Carboniferous granites from the Güneydere (Bayburt) area
Gücer, Mehmet Ali; Delimehmet, Zeynep; Çimen, Okay
Middle-Late Carboniferousgranitic rocks are widely observed in larger outcrops in the Eastern Pontide orogenic belt of the Eastern Sakarya Zone. This tectonic belt is an important part of the Anatolian plate in terms of containing igneous rocks with a wide age and composition range. This study presents new petrochemical-petrological data on Carboniferous granites in the G & uuml;neydere and surrounding area of Bayburt (NE Turkey). The granitic rocks, which include an area of approximately 5 km, represent the pre-Jurassic basement in the study area. Besides, they are unconformably overlain by Early- Middle Jurassic volcano-clastics units and Late Jurassic- Early Cretaceous limestones. They mainly consist ofgranite, granite porphyry and aplite, to a lesser extent granodiorite and quartz monzonite. Rocks have high SiO2 contents (60.43-75.51%) and high K calc-alkali to shoshonitic affinities and have been derived from an I-type source. The granitic rocks are metalumine-peralumine in character and are similar to postcollisional volcanic arc granitoids. Whole-rocks major and trace element trends show that plagioclase, hornblende, biotite, apatite, and Fe-Ti oxide mineral fractionations play an important role in the formation of the rocks. It has been revealed that fractional crystallization and assimilation+magma mixing processes play a role in the development of granites. Also, the saturation temperatures calculated from the whole-rock zircon values reflect lower initial magma temperatures. All results obtained indicate that parental magma of studied granitic rocks have evolved from lower/middle crust- derived melts as a result of partial melting and differentiated and emplaced in the continental magma chamber.
- MakaleYalnız künye2014A new 5,6-dihydro-2-pyrone derivative from Phomopsis amygdali, an endophytic fungus isolated from hazelnut (Corylus avellana)
Akay, Şeref; Ekiz, Güner; Kocabaş, Fatma; Hameş-Kocabaş, E. Esin; Korkmaz, Kemal S.; Bedir, Erdal
Aims of this study were to isolate endophytes from different parts of hazelnut - Corylus avellana L. to obtain bioactive secondary metabolites and search for the presence of gene region of taxadiene synthase (Ts), a key enzyme in taxol biosynthesis, on selected fungi. Fourteen fungal species were isolated and cultured for the screening studies. The cell-free fermentation broths were extracted with chloroform. The chloroform extracts were tested for cytotoxic activity by MTT method. Based on the activity results and chemical profiles, the isolate identified as Phomopsis amygdali by internal transcribed spaces (ITS) sequence analysis using ITS1 primer was selected for further studies. After large-scale fermentation and purification studies, two major compounds, one of which turned out to be a new secondary metabolite, were isolated and characterized. Structure of the new metabolite was elucidated as (S)-4-butoxy-6-((S)-1-hydroxypentyl)-5,6-dihydro-2H-pyran-2-one by the extensive use of 1D and 2D NMR, and HR-MS, whereas the known compound was identified as (-)pestalotin. Additionally, to evaluate taxol-producing potential of the selected isolate, a PCR amplification study followed by gel electrophoresis analysis was carried out revealing no Ts gene region.
- MakaleAçık Erişim2014Estimating aboveground biomass using landsat TM imagery: A case study of Anatolian Crimean pine forests in Turkey
Günlü, A.; Ercanli, İ.; Başkent, E.Z.; Çakır, G.
Forests play an important role in carbon circulation, and the productivity of forest ecosystems can be evaluated by evaluating its biomass. Evaluation of biomass aids the determination and understanding of changes in forest ecosystems. Because of the limitations of ground measurements of biomass, in recent times, satellite images have been broadly applied to estimate aboveground biomass (AGB). The objective of this study is to examine the relationships between AGB and individual band reflectance values and ten Vegetation Indices (VIs) obtained from a Landsat TM satellite image for a Anatolian pine forests in northwestern Turkey. Multiple regression analysis is utilized to predict the AGB. The AGB model using TM 1 and TM 2 had an adjusted R2of 0.465. Another AGB model using Enhanced Vegetation Index (EVI) and Normalized Difference 57 (ND57) had an adjusted R2 of 0.606. Our results reveal that VIs present better estimation of AGB in Anatolian pine forests as compared to individual band reflectance values.
- MakaleYalnız künye2017Morus Rubra Extract Induces Cell Cycle Arrest and Apoptosis in Human Colon Cancer Cells Through Endoplasmic Reticulum Stress and Telomerase
Demir, Selim; Turan, Ibrahim; Aliyazicioglu, Yuksel; Kilinc, Kagan; Yaman, Serap Ozer; Ayazoglu Demir, Elif; Arslan, Ayse; Mentese, Ahmet; Deger, Orhan
Many studies have reported cytotoxic effects of different Morus species, but there have been only limited studies on the cytotoxic effect of Morus rubra. The aims of this study were to evaluate the cytotoxic effect of dimethyl sulfoxide extract of M. rubra and to investigate, for the first time, its probable cytotoxic activity in human colon cancer (WiDr) cells, together with the mechanism involved. The cytotoxic activity of extract was determined using MTT assay. The mechanism involved in the cytotoxic effect of extract was then evaluated in terms of apoptosis, and the cell cycle using flow cytometry, mitochondrial membrane potential (MMP) was investigated using the fluorometric method, and expression levels of telomerase and C/EBP homologous protein (CHOP) were investigated using reverse-transcription PCR (RT-PCR). M. rubra extract exhibited moderate selective cytotoxicity on colon cancer cells compared with fibroblast cells. Extract induced cell cycle arrest at the G1 phase and apoptosis via reduced MMP in WiDr cells. Additionally, M. rubra extract significantly repressed telomerase and induced CHOP expressions in WiDr cells. Our results demonstrate that targeting telomerase and endoplasmic reticulum stress represents a promising strategy in colon cancer therapy, and M. rubra may have considerable potential for development as a novel natural product-based anticancer agent.
- MakaleAçık Erişim2021Antibiotic induced biofilm formation of novel multidrug resistant Acinetobacter baumannii ST2121 clone
Çimen, Müberra; Düzgün, Azer Özad
The aim of this study was to identify antimicrobial resistance and virulence factor genes exhibited by multidrug resistant (MDR) Acinetobacter baumannii, to analyze biofilm formation and to investigate clonal subtypes of isolate. Whole genome sequencing was done by Illumina NovaSeq 6,000 platform and multilocus sequence typing (MLST) was performed by Oxford and Pasteur typing schemes. Influence of imipenem and levofloxacin on biofilm formation was investigated in 96-well plates at 3 replicates. The strain was found to carry OXA-23, OXA-51-like, AmpC and TEM-1 beta-lactamases. The sequence of the blaOXA-51-like gene has been identified as a blaOXA-66. According to Pasteur MLST scheme the strain displayed ST2 allelic profile. However, based on Oxford MLST scheme this strain represents the new ST2121, as the gdhB gene has a single allelic mutation namely, the gdhB-227. It was determined that MDR isolate carried bap, basABCDFGHIJ, csuA/BABCDE, bauABCDEF, plcD, pgaABCD, entE, barAB, ompA, abaIR, piT2EAFTE/AUBl, fimADT, cvaC, bfmR, bfmS virulence genes. In our study imipenem induced the highest biofilm formation at a concentration of 32 mg/ml and levofloxacin at a concentration of 16 mg/ml. In conclusion, we detected a new MDR A. baumannii ST2121 clone harboring blaOXA-66 gene that has been reported for the first time in Turkey.
