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    Chemical composition, antimicrobial activities, and molecular docking studies of Turkish propolis ethanol extract
    (Czech Academy Agricultural Sciences, 2023) Ozbey, Gokben; Muz, Mustafa Necati; Tanriverdi, Elif Seren; Erkan, Sultan; Bulut, Niyazi; Otlu, Baris; Zigo, Frantisek
    The purpose of the present study was to investigate the antimicrobial effect of propolis ethanol extract col-lected from the Tarsus district of Mersin province, Kilis province, Yayladagi district of Hatay province in southern Turkiye and Sarkoy district of Tekirdag province of northwestern Turkiye against Escherichia coli (ATCC 25922), Helicobacter pylori (ATCC 43504), Pseudomonas aeruginosa (ATCC 27853), and Staphylococcus aureus (ATCC 29213). Their chemical constituents were detected via liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). They were used in a molecular docking approach to search the interactions between the propolis compounds. A total of 24 phenolic compounds were detected in all samples. 3-4 dimethoxycinnamic acid, caffeic acid and genistein were indicated to be the predominant phenolic compounds in propolis extracts by LC-MS/MS, while rutin was found in the lowest concentra-tion. Phenolic compounds were detected in a high concentration of the propolis samples collected from the Tarsus dis-trict of Mersin province. The broth microdilution method determined minimum inhibition concentration (MIC) values. MIC values ranged from 0.02 to 14 mg center dot mL-1. E. coli and S. aureus examined were as susceptible to the propolis extracts ex-cept for Mersin and Tekirdag propolis samples. The propolis sample collected from the Tarsus district of Mersin province presented the highest antibacterial activity on P aeruginosa with MIC values of 1 mg center dot mL-1. Active substances in propolis were docked to the relevant target proteins (5LMM, 4NX9, 5YHG, and 5FXT) representing E. coli (ATCC 25922), H. py-lori (ATCC 43504), P aeruginosa (ATCC 27853), and S. aureus (ATCC 29213), and with the help of molecular simulation. With this study, we indicated that the ethanol extract of propolis had a stronger antibacterial activity on S. aureus isolates than that of E. coli, H. pylori, and P aeruginosa. Although each component of propolis contributed to the antibacterial activity, the contribution of the vitexin component to the antibacterial activity was found to be quite significant.
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    Investigation for the presence of bacteria and antimicrobial resistance genes in sea snails (Rapana venosa)
    (Inst Rural Health Lublin, Poland, 2023) Ozbey, Gokben; Tanriverdi, Elif Seren; Basusta, Asiye; Lakshmanappa, Yashvanth Shaan; Otlu, Baris; Zigo, Frantisek
    Introduction and Objective. The aims of this study were to search for the presence of bacteria in sea snails (Rapana venosa) by using culturomics and Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and the antibiotic resistance/susceptibility of the sea snails.Materials and method. The anti-microbial susceptibilities of Gram-negative bacteriawas assessed by the Kirby-Bauer disk diffusion method, the presence of the mcr genes (mcr-1 to-5), the major carbapenemase and 13-lactamase resistant genes in Gram-negative bacteria, using mPCR method and 16S rRNA sequence analysis of A. hydrophila isolates.Results. Bacterial growth accounted for 100% and 94.2% in the samples of intestine and meat, respectively, in the snails. The main organisms identified by MALDI-TOF MS were A. salmonicida subsp. salmonicida at 33.7%, followed by Raoultella ornithinolytica at 9.6% (10/104) and Staphylococcus warneri at 7.7% in meat and intestine samples. Aeromonas hydrophila/ punctata (caviae), Aeromonas sobria, Klebsiella aerogenes, Klebsiella oxytoca, Raoultella planticola, Shewanella putrefaciens and Vibrio vulnificus are intrinsic or chromosomally-mediated resistant against ampicillin. No mcr genes (mcr-1 to-5), the major carbapenemase and 13-lactamase resistant genes were found. Aeromonas salmonicida subsp. salmonicida showed very low levofloxacin and meropenem resistance levels at 2.9%. When the sequence was searched in the Blast database, the genome of A. hydrophila/punctata (caviae) isolate showed high similarity with the A. hydrophila sequences. Conclusions. The findings obtained not only provide data about the proportion of bacteria in the gut and meat of the sea snails and their antibiotic resistance/susceptibility, but also show the absence of carbapenemase, colistin, and 13-lactamase resistant genes among bacterial isolates from sea snail gut microbes.
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    Investigation of bacterial pathogens in milk from mastitic dairy cattle by matrix-assisted laser desorption ionization-time of flight mass spectrometry
    (Chulalongkorn Univ, 2022) Ozbey, Gokben; Otlu, Baris; Yakupogullari, Yusuf; Celik, Betul; Tanriverdi, Elif Seren; Kelestemur, Neslihan; Safak, Tarik
    The scope of the present study was to assess the use of Matrix-Assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF) Mass Spectrometry (MS) as a quick technique for the identification of bacterial species in mastitis. In this study, milk samples from each udder quarter from a total of 250 dairy cattle were aseptically collected and tested. The samples were grouped into California Mastitis Test (CMT) positive, CMT negative and clinical mastitis. The samples were streaked on blood agar and the bacterial isolates were analysed using MALDI-TOF MS. Using MALDI-TOF MS, certain species such as Staphylococcus chromogenes (44/188, 23.4%), Aerococcus viridans (40/188, 21.3%) and Staphylococcus haemolyticus (19/188, 10.1%) were identified at a higher proportion in milk samples from cattle that were CMT positive. Moreover, the most common bacteria isolated from CMT negative milk samples were A. viridans (56/161, 34.8%), S. haemolyticus (24/161, 14.9%) and S. chromogenes (17/161, 10.6%). Only one isolate of S. chromogenes (1/4, 25%), A. viridans (1/4, 25%), S. haemolyticus (1/4, 25%) and Enterococcus faecium (1/4, 25%) was detected from milk samples with clinical mastitis using MALDI-TOF MS. There was a concurrence between the MALDI-TOF and biochemical bacterial identification method in 325 of 353 samples (92.06%). This study concludes that MALDI-TOF can be applied for quick determination of bacterial isolates once the bacterial colony has been isolated in milk samples.