Yazar "Erol, Ozlem" seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • [ X ]
    Öğe
    Distribution of antibiotic resistance and the presence of vancomycin-resistance genes (vanA and vanB) in Enterobacteriaceae isolated from the Sea of Marmara, the Canakkale Strait and the Istanbul Strait, Turkey
    (Walter De Gruyter Gmbh, 2016) Cardak, Mine; Altug, Gulsen; Ay, Mustafa; Erol, Ozlem
    We investigated the frequency of antibiotic resistance of Enterobacteriaceae and the presence of vancomyc-in-resistance genes in samples taken from the Sea of Marmara, and the Istanbul and Canakkale Straits, Turkey. Different colony -forming bacteria were isolated and identified with the VITEK 2 Compact 30 system. The antibiotic resistance of the isolates was determined by the disc diffusion method. The isolates were tested against amoxicilin, ampicillin, aztreonam, ceftazidime, cefotaxime, cefuroxime, ofloxacin, vancomycin, tetracycline, kanamycin and gentamycin. The presence of vancomyctn-resistance genes (vanA and vanB) was also investigated. The level of Enterobucteriaceue species was higher in the Sea of Marmara than in the Istanbul Strait and the Canakkale Strait. Isolates showing resistance to the greatest number of antibiotics were identified from E. colt isolates. The resistance of the selected bacterial isolates were as follows: kanamycin (82%), vancomycin (78%) and ampicillin (60%). Some intermediately vancomycin-resistant Enterobacteriaceae isolates had the vanA gene. This study provides evidence of widespread bacterial resistance to clinically relevant antibiotics in marine environments. It also contributes to the knowledge on the distribution of antibiotic resistance among Enterobacteriaceae and indicates the importance of control measures in domestic water treatment.
  • [ X ]
    Öğe
    Phenols of virgin olive oil protects nuclear DNA against oxidative damage in HeLa cells
    (Pergamon-Elsevier Science Ltd, 2012) Erol, Ozlem; Arda, Nazli; Erdem, Gunnhan
    Oxidative DNA damage is an inescapable consequence for cells constantly exposed to oxidative stress derived from normal metabolic processes and from environmental factors. Phenolic compounds, which have strong antioxidant activity, prevent DNA damage by protecting the cells against harmful effects of oxidative stress. In this study, the effect of virgin olive oil phenolic extract (OOPE) was investigated on H2O2-induced mitochondrial DNA (mtDNA) and nuclear DNA (nDNA) damage in HeLa cells. DNA damage was assessed in mitochondria and two nuclear regions by using quantitative PCR (QPCR) assay. The cells were pre-treated with non-cytotoxic doses of OOPE for 4 h, and DNA damage was determined. OOPE alone does not change the steady-state level of DNA damage. The oxidative stress generated with 750 mu M H2O2 caused two times greater damages in mtDNA compared to nDNA, which included the nonexpressed beta-globin region (1.507 +/- 0.110 lesions/10 kb) and the expressed APEX1 gene (1.623 +/- 0.243 lesions/10 kb) with respect to the control region. When cells were preincubated with OOPE for 4 h, nDNA damage under stress condition was completely inhibited; however, mtDNA damage was not affected by this procedure. These results suggest that OOPE has a protective effect against nDNA damage in HeLa cells. (C) 2012 Elsevier Ltd. All rights reserved.
  • [ X ]
    Öğe
    Viscum album L. Extracts Protects HeLa Cells against Nuclear and Mitochondrial DNA Damage
    (Hindawi Ltd, 2012) Onay-Ucar, Evren; Erol, Ozlem; Kandemir, Basak; Mertoglu, Elif; Karagoz, Ali; Arda, Nazli
    Viscum album L. is a semiparasitic plant grown on trees and widely used for the treatment of many diseases in traditional and complementary therapy. It is well known that some activities of Viscum album extracts are varied depending on the host trees, such as antioxidant, apoptosis-inducing, anticancer activities of the plant. The aim of the present study is to examine the comparative effects of methanolic extracts of V. album grown on three different host trees (locust tree, lime tree, and hedge maple tree) on H2O2-induced DNA damage in HeLa cells. Oxidative damage in mitochondrial DNA and two nuclear regions was assessed by QPCR assay. The cells were pretreated with methanolic extracts (10 mu g/mL) for 48 h, followed by the treatment with 750 mu M H2O2 for 1 hour. DNA damage was significantly induced by H2O2 while it was inhibited by V. album extracts. All extracts completely protected against nuclear DNA damage. While the extract from lime tree or white locust tree entirely inhibited mitochondrial DNA damage, that from hedge maple tree inhibited by only 50%. These results suggest that methanolic extracts of V. album can prevent oxidative DNA damage, and the activity is dependent on the host tree.