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Öğe The Characterization and Beta-Lactam Resistance of Staphylococcal Community Recovered from Raw Bovine Milk(Mdpi, 2023) Sipahi, Nisa; Kaya, Ertugrul; Celik, Cansu; Pinar, OrhanStaphylococci is an opportunistic bacterial population that is permanent in the normal flora of milk and poses a serious threat to animal and human health with some virulence factors and antibiotic-resistance genes. This study was aimed at identifying staphylococcal species isolated from raw milk and to determine hemolysis, biofilm, coagulase activities, and beta-lactam resistance. The raw milk samples were collected from the Duzce (Turkiye) region, and the study data represent a first for this region. The characterization of the bacteria was performed with MALDI-TOF MS and 16S rRNA sequence analysis. The presence of coa, icaB, blaZ, and mecA was investigated with PCR. A nitrocefin chromogenic assay was used for beta-lactamase screening. In this context, 84 staphylococci were isolated from 10 different species, and the dominant species was determined as S. aureus (32.14%). Although 32.14% of all staphylococci were positive for beta hemolysis, the icaB gene was found in 57.14%, coa in 46.42%, mecA in 15.47%, and blaZ in 8.33%. As a result, Staphylococcus spp. strains that were isolated from raw milk in this study contained some virulence factors at a high level, but also contained a relatively low level of beta-lactam resistance genes. However, considering the animal-environment-human interaction, it is considered that the current situation must be monitored constantly in terms of resistance concerns. It must not be forgotten that the development of resistance is in constant change among bacteria.Öğe Corrosion behavior of dual phase 600 and 800 steels in 3.5wt.% NaCl environment(Taylor & Francis Ltd, 2020) Gerengi, Husnu; Sen, Nuri; Uygur, Ilyas; Kaya, ErtugrulDual phase (DP) steels have a great deal of importance in the automotive industry. These steels are used to fabricate structural parts of vehicles with the goal of passenger safety. In this study, the corrosion properties of DP 600 and 800 steel in 3.5wt.% NaCl environment were evaluated using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), and weight loss methods. Although the samples were quite similar to each other in their composition, it was observed that the very small differences changed the corrosion resistance property. For this reason, the calculated charge transfer resistance (R-ct) of the DP-800 in the 3.5wt.% NaCl environment was 51% greater than that of the DP-600 sample. This finding was confirmed by using weight loss, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), and optical profilometer (OP) analysis.Öğe Determination of amatoxin concentration in heat-treated samples of Amanita phalloides by high-performance liquid chromatography: A forensic approach(Elsevier Sci Ltd, 2021) Sharma, Spriha; Aydin, Meryem; Bansal, Gulshan; Kaya, Ertugrul; Singh, Rajinder[Abstract Not Available]Öğe An easy route for preparation of carboxylic acid and urea functional block copolymer as corrosion inhibitor(Taylor & Francis Ltd, 2024) Ince, Ahmet; Koramaz, Ilayda; Kaya, Ertugrul; Karagoz, BunyaminA novel POEGMA-b-(PMEEU-co-PMAA) (poly(oligo(ethylene glycol) methacrylate)-b-poly((methacrylamidoethyl) ethylene urea)-co-poly(methacrylic acid) block copolymer has been synthesized by RAFT polymerization as a corrosion inhibitor. Structural characterization of the block copolymer was done by FTIR, C-13 NMR and H-1 NMR spectroscopic techniques. The carboxylic acid and cyclic urea units on the block copolymer exert a synergistic effect on corrosion inhibition through chelating of the metal ions or adsorption to the metal surface. Corrosion inhibition of SAE 1012 carbon steel in a 1 M HCl medium has been investigated in the presence of 5 mM polymer using both experimental (electrochemical impedance spectroscopy, Tafel polarization (TP), weight loss) and theoretical approaches. Also, SAE 1012 carbon steel surface morphology changes were followed by energy dispersive X-ray spectroscopy and scanning electron microscopy. Electrochemical techniques indicated that the presence of PMEEU-co-PMAA segments of the polymer in the acid solution inhibits corrosion of SAE 1012 carbon steel. The inhibition efficiency of the polymer was found to be about 85%. According to TP studies, PMEEU-co-PMAA segment acts as a mixed type corrosion inhibitor. The adsorption of PMEEU-co-PMAA molecules onto the metal surface follows Langmuir adsorption isotherm. The K-ads value calculated from the equilibrium constant of the adsorption process reflects a strong interaction. SEM and EDAX studies provide evidence of PMEEU-co-PMAA adsorption on the metal surface.Öğe Effect of Chemical Treatment on the Corrosion Behavior of Mg-2Zn-1Mn (ZM21) Magnesium Alloy(Springer, 2024) Kaya, Ertugrul; Gerengi, Husnu; Cabrini, MarinaMagnesium alloys have gained interest as biomedical implant materials in dental and orthopedic applications due to their biodegradability and similarities to human bones. However, their high rate of degradation in physiological systems poses a significant challenge for their use. To address this issue, chemical modification is being explored to improve the corrosion resistance of magnesium and its alloys. In this study, they investigated the effects of chemical modification using NaOH and H2O2 on the bioactivity and corrosion resistance of a Mg-2Zn-1Mn (ZM21) magnesium alloy in simulated body fluid (SBF) using advanced techniques such as dynamic electrochemical impedance spectroscopy (dynamic EIS), electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), atomic force microscopy, and x-ray diffraction (XRD). Results obtained using DEIS measurements after 30 hours showed that the charge transfer resistance of the untreated ZM21 alloy was 229.4, 1226.8 omega cm(2) for the NaOH-treated surface, and 1066.3 omega cm(2) for the H2O2-treated surface. The study found that NaOH is more effective than H2O2 in improving the corrosion resistance of the ZM21 magnesium alloy in simulated body fluid. Additionally, the mechanism of corrosion for both untreated and treated samples in the corrosive environment was investigated and discussed in the study.Öğe First Report of a Neotropical Agaric (Lepiota spiculata, Agaricales, Basidiomycota) Containing Lethal alpha-Amanitin at Toxicologically Relevant Levels(Frontiers Media Sa, 2020) Angelini, Claudio; Vizzini, Alfredo; Justo, Alfredo; Bizzi, Alberto; Davoli, Paolo; Kaya, ErtugrulA recent collection ofLepiota spiculatafrom the Dominican Republic is presented here. Macro- and micromorphological features ofL. spiculataare described in detail, and its evolutionary (phylogenetic) position withinLepiotasect.Ovisporae, in the subincarnata/brunneoincarnata clade, is assessed on the basis of a combined nrLSU + nrITS +rpb2+tef1analysis. Additionally, high levels of deadly amatoxins were detected and quantified inL. spiculatafor the first time by HPLC analysis; in particular, alpha-amanitin was found at concentrations up to approximately 4 mg/g dry weight, which renderL. spiculataa potentially lethal mushroom, if ingested.Öğe Gene expression profiles for apoptotic and necrotic pathways during Amanita phalloides intoxication in mice(Istanbul Univ, Fac Pharmacy, 2022) Karahan, Selim; Atli, Zehra; Kaya, Ertugrul; Ozdemir, Feride; Boga, Mehmet; Izgi, SevcanBackground and Aims: Amanita phalloides is the deadliest toxic mushroom in the world and causes death from acute liver failure. alpha-amanitin (alpha-AMA), the most potent toxin, inhibits RNA polymerase II in hepatocytes, stops protein synthesis, and causes hepatotoxicity. However, the information about the mechanisms underlying hepatotoxicity caused by alpha-AMA is quite inadequate. This study aims to reveal the complex necrotic and apoptotic mechanisms occurring in mouse hepatocytes de-pending on A. phalloides exposure time in vivo.Methods: BALB-c male mice were divided into 5 groups (n=7): control, alpha-AMA-2, alpha-AMA-12, alpha-AMA-72, and alpha-AMA-96 groups. A poisoning model was created by oral administration of A. phalloides mushroom extract containing 10 mg/kg of alpha-AMA to mice and they were sacrificed after 2, 12, 72, and 96 h. Then, TNF-alpha, Bax, caspase-3, and Bcl-2 gene expression levels in liver tissues were examined by the RT-qPCR method. Time-dependent damage to liver tissues was also evaluated histopathologically.Results: RT-qPCR results showed that proinflammatory cytokine TNF-alpha mRNA expression levels increased in mouse liver tissues at 2 and 12 h afterA. phalloides administration compared among the groups. BaxmRNA expression levels increased in the 12 and 72 h afterA. phalloides ingestion. It was observed that caspase-3 mRNA expression levels increased in the 72 and 96 h groups compared among the groups, while Bcl-2 mRNA expression levels decreased in the 72 and 96 h groups.Conclusion: Our findings showed that necrotic mechanisms develop in the early period afterA. phalloides mushroom poison-ing, and then apoptotic mechanisms are effective. In conclusion, understanding the mechanisms of A. phalloides-induced hepatotoxicity will provide important information for new treatment strategies to be developed.Öğe Investigation of Total Phenolic Content of Tilia dasystyla and Polygonatum orientale Desf Extracts and Their Cytotoxic Effect on the Osteogenic Sarcoma (Saos-2) Cancer Cell Line(Kowsar Publ, 2020) Zarringhalami, Roshanak; Hanachi, Parichehr; Kaya, Ertugrul; Agan, Aydan Fulden; Agan, Kagan; Donmez, MertBackground: Osteosarcoma; is one of the most common malignant tumors. Nowadays, because of the many side effects of cancer drugs, the usage of herbal medicine which can inhibit or eliminate cancer cells by their antioxidant compounds is increased. Objectives: In the present study anticancer effect of Tilia dasystyla and Polygonatum orientale Desf different extracts on osteogenic sarcoma (Saos-2) cancer cell line was investigated and their polyphenolic compounds were identified by liquid chromatography-mass spectrometry (LC-MS) analysis. The cytotoxic effect of these extracts on Saos-2 cell line and identification of their phenolic compounds have not been reported so far. Methods: Cancer cell lines were provided from Department of Biological Sciences, Bursa University, Turkey. Different concentrations of the methanol, ethanol, and diluted water extracts (0.5 - 5 mg/mL) were tested on Saos-2 cell line. After 24, 48, and 72 hours, the cell viability was evaluated using 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. For the investigation of total phenolic compounds of T. dasystyla and P. orientale Desf extracts LC-MS method was applied. Results: According to the results diluted water extracts on the Saos-2 cancer cell line showed more cytotoxic effect than other solvents. The lowest IC50 value was 0.58 +/- 0.01 mg/mL within 72 hours belonged to T. dasystyla water extract. Conclusions: Tilia dasystyla and Polygonatum orientale Desf extracts contain some polyphenolic compounds which showed cytotoxic effect on Saos-2 cancer cell line. The full potential of these herbal extracts is yet to be realized by further studies on animal models and subsequent trials.Öğe Synthesis and anticorrosion studies of 4-[(2-nitroacetophenonylidene)-amino]-antipyrine on SAE 1012 carbon steel in 15 wt.% HCl solution(Taylor & Francis Ltd, 2020) Gerengi, Husnu; Cakmak, Resit; Dag, Besir; Solomon, Moses M.; Tuysuz, Hatice Aslihan Akbal; Kaya, ErtugrulA novel corrosion inhibitor, ((E)-1,5-dimethyl-4-((1-(3-nitrophenyl)ethylidene)amino)-2-phenyl-1,2-dihydro-3H-pyrazol-3-one) (DNPP) was synthesized in high yield by the condensation reaction of 4-aminoantipyrine with 2-nitroacetphenone derived from acetophenone as a starting material and characterized by FT-IR,H-1, and(13)C NMR techniques. DNPP was tested against the corrosion of SAE 1012 carbon steel in 15 wt.% HCl solution using electrochemical and surface characterization techniques. Results obtained show that DNPP is effective in retarding the corrosion of SAE 1012 carbon steel. With 4 mM of DNPP, the charge transfer resistance of SAE 1012 in 15 wt.% HCl solution is raised from 17.42 to 140.50 ohm cm(2)and the substrate surface is protected by 87%. The inhibition is through adsorption mechanism (mixed-adsorption type) and has been confirmed by SEM and EDAX results. Potentiodynamic polarization results reveal that DNPP acted as a mixed-type corrosion inhibitor. DNPP is a promising candidate for the formulation of an inhibitor cocktail for the strong acid environment.Öğe Toxin components and toxicological importance of Galerina marginata from Turkey(Pergamon-Elsevier Science Ltd, 2020) Akata, Ilgaz; Yilmaz, Ismail; Kaya, Ertugrul; Coskun, Nuri Cenk; Donmez, MertAmatoxins, most of which are hepatotoxic, can cause fatal intoxication. While mushrooms in the amatoxin-containing Galerina genus are rare, they can poison humans and animals worldwide. Few studies have profiled the toxicity of Galerina marginata. In addition, many studies indicate that macrofungi can have different characteristics in different regions. In this study, the quantities of toxins present in G. marginata from different provinces in Turkey were analysed using reversed-phase high-performance liquid chromatography with ultraviolet detection (RP-HPLC-UV) and liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). G. marginata samples were collected from three different regions of Turkey. The taxonomic categorization of mushrooms was based on their micro- and macroscopic characteristics. The presence of toxins alpha-amanitin (AA), beta-amanitin (BA), gamma-amanitin (GA), phalloidin (PHD) and phallacidin (PHC) quantities were measured using RP-HPLC-UV and then were confirmed using LC-ESI-MS/MS. BA levels were higher than AA levels in G. marginata mushrooms collected from all three regions. Moreover, the levels of GA were below the detection limit and no phallotoxins were detected. This is the first study to identify and test the toxicity of G. marginata collected from three different regions of Turkey using RP-HPLC-UV. This is also the first study to confirm the UV absorption of amatoxins in G. marginata using LC-ESI-MS/MS, which is a far more sensitive process. More studies evaluating the toxicity of G. marginata in other geographic regions of the world are needed.
