Browsing by Author "Ay, Mustafa"

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Antibiotic resistance and virulence genes in enterococcus species isolated from raw and processed seafood
(Springer India, 2021-12-01) Cardak, Mine; Ay, Mustafa; Karaalioglu, Onur; Erol, Ozlem; Bagci, Ufuk; Ozmen Togay, Sine; ÖZMEN TOĞAY, SİNE; Bursa Uludağ Üniversitesi/Ziraat Fakültesi.; IZQ-1342-2023; V-5408-2017; AAC-2693-2021; JFA-0267-2023
This study evaluated the antibiotic resistance characteristics and virulence genes of enterococci isolated from raw and processed seafood sold in the Marmara Region, Turkey. In this context, the enterococcal load was determined as between 1.0 and 2.5 log CFU/g in 39 of a total of 397 samples. It was determined that 117 strains isolated from the samples belonged to Enterococcus gallinarum, E. casseliflavus, E. durans, E. faecium, and E. faecalis species. Erythromycin, tetracycline, streptomycin, and gentamicin resistance was observed, whereas the tetM, ermB, aac(6')-aph(2'')-la genes were found in a majority of the isolates. It was also determined that the isolates carried the agg2 and gelE virulence genes. When all these results are evaluated, the presence of these isolates in aquatic products may pose a risk in terms of food safety and public health.
Antimicrobial activity potential of enterococcus spp. isolated from some traditional Turkish cheeses
(Kafkas Üniversitesi, 2016-04-19) Ay, Mustafa; Altunatmaz, Sema Sandıkcı; Aksu, Filiz Yılmaz; Tınaztepe, Özlem Erol; Issa, Ghassan; Büyükünal, Serkan Kemal; Togay, Sine Özmen; Uludağ Üniversitesi/Ziraat Fakültesi/Gıda Mühendisliği Bölümü.; 36468917400
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.
Asit boyarmaddenin (β-naftoloranj) elektrik alanında sentezi
(Uludağ Üniversitesi, 1995) Ay, Mustafa; Çetin, Mehmet; Uludağ Üniversitesi/Fen Bilimleri Enstitüsü/Kimya Anabilim Dalı.
Çalışmamızın ilk kesiminde β-Naftol Oranj klasik yöntemde ve farklı çözgenlerde (su, alkol) ve çözgenin (su, alkol) farklı miktarlarında sentezlendi. Sonra bu işlemlere dışarıdan 10 kV’luk potansiyel uygulandı. Tekrar dış potansiyel reaksiyonun ara kademelerinde uygulandı. Reaksiyon ürünlerinin değişim miktarları yüzde verim hesablarından izlenmiştir. Sonra bu değişimler basit bir yaklaşımla Aktivasyon enerjisine bağlı olarak hesaplanmıştır.
Investigation of antimicrobial activity and entA and entB genes in Enterococcus faecium and Enterococcus faecalis strains isolated from naturally fermented Turkish white cheeses
(Korean Society Food Science & Technology-Kosfost, 2016-08-16) Ay, Mustafa; Güneşer, Onur; Yüceer, Yonca Karagül; Toğay, Sine Özmen; Uludağ Üniversitesi/Ziraat Fakültesi/Gıda Mühendisliği Bölümü.; AAC-6337-2021; 36468917400
In this research, the antagonistic effects of Enterococcus faecalis and E. faecium bacteria isolated from naturally fermented Turkish white cheeses, produced without starter culture, against Listeria monocytogenes, L. innocua, L. ivanovii, Staphylococcus aureus, and E. faecalis were evaluated. The presence of entA and entB genes was also detected in the isolates, which had antimicrobial activity. Total 71 strains of E. faecalis and 7 strains of E. faecium were tested; 20 of E. faecalis and none of E. faecium strains showed antimicrobial activity against the tested bacteria using agar spot method. Among E. faecalis strains, which had antimicrobial activity, three strains contained both entA and entB genes, two strains carried only entA gene, and five strains had only entB gene. These cheese-sourced enterococcal strains or their enterocins should be considered to be used for food preservation especially in the dairy industry.
Probiotic characteristics of bacteriocin-producing Enterococcus faecium strains isolated from human milk and colostrum
(Springer, 2019-11) Bağcı, Ufuk; Temiz, Ayhan; Ay, Mustafa; Togay, Sine Ozmen; Bursa Uludağ Üniversitesi/Ziraat Fakültesi/Gıda Mühendisliği/Gıda Bilimleri Bölümü.; AAC-6337-2021; 36468917400
As potential probiotic traits of human milk-isolated bacteria have increasingly been recognized, this study aimed to evaluate the probiotic properties of bacteriocin-producing Enterococcus faecium strains isolated from human milk and colostrum. Among 118 human milk- and colostrum-isolated lactic cocci, only 29 were identified as Enterococcus. Of these, only four Enterococcus faecium isolates exhibited bacteriocigenic activity against several pathogenic Gram-positive bacteria, including Listeria monocytogenes. These isolates exhibited high acid (up to pH 3.0) and bile tolerance (0.5% oxgall) in simulated gastrointestinal conditions, demonstrating their ability to survive through the upper gastrointestinal tract. All of the E. faecium strains were shown to be sensitive to most of the antibiotics including vancomycin, tetracycline, rifampicin, and erythromycin, while they were resistant to kanamycin and chloramphenicol. None of the strains showed any virulence (gelE, agg2, clyA, clyB, clyM) and antibiotic resistance genes (vanA, vanB, ermB, tetM, and aac(6')-le-aph(2 '')-la). In addition, all the strains were able to assimilate cholesterol, ranging between 25.2-64.1% and they exhibited variable adherence (19-36%) to Caco-2 cells. Based on the overall results of this in vitro study, four of the E. faecium strains isolated from human milk and colostrum can be considered as promising probiotic candidates; however, further in vivo evaluations are required.
Regio- and diastereoselective 1,3-dipolar cycloaddition of imidazoline 3-oxides to styrene
(Pergamon-Elsevier Science, 1998-03-01) Coşkun, Necdet; Ay, Mustafa; Uludağ Üniversitesi/Fen Edebiyat Fakültesi/Kimya Bölümü.
Delta(3)-Imidazoline 3-oxides (1) underwent regio- and diastereoselective cycloaddition with styrene to give perhydroimidazo[1,5-b]isoxazoles (3). Thermally induced retro cycloaddition of compounds (3) was demonstrated.