In this study, the antimicrobial activity of a bacteriocin produced by Enterococcus faecalis KT11, isolated from traditional Kargı Tulum cheese, was determined, and bacteriocin KT11 was partially characterized. The results showed that bacteriocin KT11 was antagonistically effective against various Gram-positive and Gram-negative test bacteria, including vancomycin- and/or methicillin-resistant bacteria. The activity of bacteriocin KT11 was completely abolished after treatment with proteolytic enzymes (proteinase K, α-chymotrypsin, protease and trypsin), which demonstrates the proteinaceous nature of this bacteriocin. Additionally, bacteriocin KT11 remained stable at pH values ranging from 2 to 11 and after autoclaving at 121℃ for 30 min. In addition, the activity of bacteriocin KT11 was stable after treatment with several surfactants (EDTA, SDS, Triton X-100, Tween 80 and urea) and organic solvents (chloroform, propanol, methanol, ethyl alcohol, acetone, hexane and ethyl ether). Cell-free supernatant of E. faecalis KT11 was subjected to ammonium sulfate precipitation and then desalted by using a 3.5-kDa cut-off dialysis membrane. The bacteriocin activity was determined to be 711 AU/mL in the dialysate. After tricine-SDS-PAGE analysis, one peptide band, which had a molecular weight of ~3.5 kDa, exhibited antimicrobial activity. Because the bacteriocin KT11, isolated from E. faecalis KT11, exhibits a broad antimicrobial spectrum, heat stability and stability over a wide pH range, this bacteriocin can be used as a potential bio-preservative in foods. Additionally, bacteriocin KT11 alone or in combination with conventional antibiotics may provide a therapeutic option for the treatment of multidrug-resistant clinical pathogens after further in vivo studies.

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In this study, the essential oil compositions and antimicrobial and anticholinesterase activities of three Turkish endemic Salvia species were investigated. The gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) analysis of the essential oils obtained from Salvia dicroantha, Salvia verticillata subsp. amasiaca, and Salvia wiedemannii showed that the major constituents were caryophyllene oxide (22.4%), Germacrene D (36.6%), and α-pinene (36.2%), respectively. All essential oils exhibited antimicrobial activity against tested Gram-positive and Gramnegative bacteria, and test yeast strains. The minimum inhibitory concentrations (MICs) of oils ranged from 12.5 to 50.0 µl/ml. Additionally, essential oils were more active than standard antifungals, inhibiting test strains of yeasts such as Candida albicans, Candida glabrata, and Saccharomyces cerevisiae. At 400 µM concentration, the essential oil of S. wiedemannii had moderate acetylcholinesterase (55.95±2.01%), and butyrylcholinesterase (50.97±3.12%) inhibitory activity, while other two species no activity against both enzymes.

Ethics approval (IRB/IACUC) (This field may be published.) This manuscript does not require IRB/IACUC approval because there are no human and animal participants.