Phenols of virgin olive oil protects nuclear DNA against oxidative damage in HeLa cells

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

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

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

Antimicrobial activity potential of enterococcus spp. isolated from some traditional Turkish cheeses [Bazı geleneksel Türk peynirlerinden ızole edilen enterococcus spp.’nin antimikrobiyal aktivite potansiyeli]

Enterococci can produce enterocins which have antimicrobial activity against Gram-positive and also Gram-negative pathogenic, toxigenic and food-spoilage bacteria. The aim of this study was to determine the antimicrobial activity of Enterococcus spp. isolated from traditional Turkish cheeses such as Kashar, Manyas, Sepet, Kelle, Mihalic, Tulum. The isolates were tested against Listeria monocytogenes, Listeria innocua, Listeria ivanovii, Staphylococcus aureus and Enterococcus faecalis and also detected the presence of entA and entB genes of these isolates. Total 66 of enterococcal isolates were obtained from 34 of cheese samples and 25 of these isolates showed antimicrobial activity against tested reference bacteria by using agar spotting method. Also it was determined most of Enterococcus spp. carried enterocin encoding entA and entB genes. We concluded that these isolates or their enterocins may have a potential for food preservation, however they should be evaluated in terms of food safety. © 2016, Veteriner Fakultesi Dergisi. All rights reserved