Yazar "Uyar, F" seçeneğine göre listele

Listeleniyor 1 - 8 / 8
  • [ X ]
    Öğe
    Antimicrobial activities of some thyme (Thymus, Staureja, Origanum and Thymbra) species against important plant pathogens
    (Mrs Pushpa Agarwal, 2006) Kizil, S; Uyar, F
    Different types of plants are used as thyme, such as Tyhmbra, Origanum, Satureja, Thymus and Coridathymus in various regions of the world. In the present study, essential oil components of Thymus kotschyanus, Satureja hortensis, Origanum onites and Thymbra spicata were determined by GC and antimicrobial and antifungal activities of essential oils of these plants against four plant pathogens were evaluated at concentrations of 5, 10 and 15 mu g and incubation times of 24, 48 and 72 It. ne major components of the essential oils determined by GC were thymol (41.6%) in Thymus kotschyanus, carvacrol in Origanum onites (40.7%), Satureja hortensis (20.6%) and Thymbra spicata (81%). Aqueous and hexane extracts of each plant were tested for their antibacterial activity by using agar disk diffusion method. The results indicated that all essential oils exhibit antibacterial activity against Clavibacter michiganensis subsp. michiganensis, Pseduomonas syringae pv. tomato and Macrophomina phaseoli, except Xanthomonas campestris pv. malvacearum. In addition, it has been observed that gram +ve bacteria are more sensitive than gram -ve bacteria.
  • [ X ]
    Öğe
    A comparative study of bioassays based on enzyme biosynthesis in Escherichia coli and Bacillus subtilis exposed to heavy metals and organic pesticides
    (Elsevier Science Inc, 2003) Guven, K; Togrul, S; Uyar, F; Ozant, S; De Pomerai, DI
    Two enzyme assays, namely beta-galactosidase in Escherichia coli (E.C.3.2.1.23) and alpha-amylase in Bacillus subtilis (E.C.3.2.1.1), were compared following exposure to various concentrations of heavy metals and organic pesticides. It was shown that alpha-amylase biosynthesis in the Gram-positive bacteria was more sensitive to heavy metals, particularly to mercury as low as 0.1 ppm, compared to beta-galactosidase in the Gram-negative bacteria. The results of organic pesticide treatment were more clear-cm when comparing both assays. Alpha-amylase test system can detect the inhibition by the organometallic fungicides Maneb and Mancozeb at as low as 0.1 ppm, while no inhibition with beta-galactosidase system up to as high as 100 ppm. The effect of organic insecticide endosulfan on alpha-amylase was also seen at very low concentrations (0.048 ppm). The electrophoretic analysis also revealed the inhibition of enzyme biosynthesis at the tested toxicant concentrations. (C) 2003 Elsevier Science Inc. All rights reserved.
  • [ X ]
    Öğe
    Effect of bovine serum albumine on production of alpha-amylase and amylase thermostability in Bacillus subtilis
    (Mbr Press Inc, 1997) Otludil, B; Ensari, NY; Aguloglu, S; Uyar, F
    Thermal stability of alpha-amylase from Bacillus subtilis isolated from thermal Cermik hot spring was studied. alpha-amylase was purified from media with and without bovine serum albumen (BSA). The enzyme was stable at 68 degrees C when purified from media with different concentrations of BSA;however,it was observed to be stable at 75 degrees C when interacted with different concentrations of BSA. B. subtilis was grown in different concentrations of BSA. The best bacterial growth was identified to be in the medium with 180 mu g/ml BSA. Production of alpha-amylase and proteases was induced in presence of 180-240 mu g/ml BSA.
  • [ X ]
    Öğe
    Effect of nonionizing radiation on plasmid DNA of E.coli puc9
    (Mbr Press Inc, 1999) Dasdag, S; Celik, MS; Uyar, F; Akdag, MZ; Sert, C; Ensari, Y
    The present experiment was carried out to investigate whether 9450 MHz and 2450 MHz microwave exposure (MW) affect to the plasmid DNA of Escherichia coli puc 9 or not. Suspensions of E.coli puc 9 were exposed to microwave radiation at 2450 MHz (55,110,165,220 and 275 W for 30 and 60 second) and 9450 MHz (2.65mW/cm(2) for 10,20,40 and 60 minutes). However, plasmid DNA of E.coli puc 9 were also exposed to 9450 MHz (10,20,40 and 60 minutes) and 2450 MHz (55,110,165,220 and 275 W for 30 and 60 second) Microwave. After exposures of E.coli puc 9, the plasmid DNA were isolated and evaluated by AGE assay. We found that amount of plasmid DNA was not changed in 9450 MHz and 2450 MHz MW exposure. The difference of temperatures between before and after 2450 MHz MW exposures were found to be significant (P<0.01). It was concluded that E.coli puc 9 plasmid DNA was not affected by 9450 MHz and 2450 MHz Microwave radiation.
  • [ X ]
    Öğe
    Production and optimization of process parameters for alkaline protease production by a newly isolated Bacillus sp under solid state fermentation
    (Elsevier Sci Ltd, 2004) Uyar, F; Baysal, Z
    Production of alkaline protease employing the laboratory isolate, Bacillus sp. under solid state fermentation (SSF) was optimized. The effect of wheat bran and lentil husk was examined. Wheat bran showed highest enzyme production. The appropriate incubation time, inoculum size, moisture level and buffer solution level were determined. Maximum yields of 429.041 and 168.640 U g(-1) were achieved by employing wheat bran and lentil husk as substrates in 0.1 M carbonate/bicarbonate buffer at pH 10 with 30 and 40% initial moisture level at 24 h. Inoculum size and buffer solution level were found to be 20 and 25% and 0.5:1 for wheat bran and lentil husk, respectively. (C) 2003 Elsevier Ltd. All rights reserved.
  • [ X ]
    Öğe
    Production of a-amylase by thermotolerant Bacillus subtilis in the presence of some carbon, nitrogen containing compounds and surfactants
    (Inst Microbiologia, 2003) Baysal, Z; Uyar, F; Aytekin, Ç
    The effect of some carbon, nitrogen sources and surfactants on the alpha-amylase production of Bacillus subtilis isolated from hot-spring water was investigated. Galactose, glucose, xylose, sucrose. fructose or corn starch were used as a carbon sources for production of alpha-amylase. Methionine, glycine, aspartic acid, lysine, (NH4)(2)SO4, NH4Cl, (NH4)(2)S2O8 and NH4NO3 were used as a organic and inorganic nitrogen sources, respectively. The higher alpha-amylase production was determined in corn starch, Sucrose, fructose and galactose compared to other sugars and with lysine and methionine than compared with other organic nitrogen sources. Nitrate and aspartic acid are clearly not as good a nitrogen Source for alpha-amylase production. When Triton X 100, sodium dodecyl Sulphate (SDS) and Tween 40 were employed in growth medium, although bacterial growth was found high, enzyme production was not detectable. Soluble starch and yeast extract were used in order to evaluate the influence of the medium composition on the alpha-amylase production instead of sole carbon and nitrogen Sources. Maximum enzyme production was found in 3.5 % and 1.5% soluble starch and yeast extract growth media, respectively.
  • [ X ]
    Öğe
    Purification and some characterization of an extracellular ?-amylase from a thermotolerant Bacillus subtilis
    (Springer, 2003) Uyar, F; Baysal, Z; Dogru, M
    Extracellular alpha-amylase from Bacillus subtilis was purified by ion-exchange chromatography and gel filtration. The molecular weight was determined to be 48.000. Various metal ions inhibited alpha-amylase activity even at low concentrations (5 mM). Ca2+, Ba2+, m,(2+) and Ni2+ were mild inhibitors, whereas Zn2+, Fe2+, Pb2+, H2+ Mg2+, Cd2+ and Cu2+ were potent inhibitors. The activity of the enzyme was reduced by Ca2+ at high concentrations but increased at 2.5 mM. Ethylenediaminetetraacedicacid (EDTA) also affected the enzyme activity even when compared with Ca2+ ions at low concentrations. Calcium and EDTA showed dose-dependent inhibition. Different enzyme solution containing Ca2+, Ba2+ and Mg2+ (2.5 mM and 10 mM) was added 2.5 mM EDTA and enzyme activity increased at 10 mM metal ions concentrations. The K-m and V-max values for alpha-amylase were found to be 2.2 x 10(-4) g mL(-1) and 0.020 U mL(-1), 2.91 x 10(-4) g mL(-1) and 0.016 U mL(-1), 4.04 x 10(-4) g mL(-1) and 0.021 U mL(-1) for starch, amylose and glycogen. respectively.
  • [ X ]
    Öğe
    Solid state fermentation for production of ?-amylase by a thermotolerant Bacillus subtilis from hot-spring water
    (Elsevier Sci Ltd, 2003) Baysal, Z; Uyar, F; Aytekin, C
    The production of extracellular a-amylase by thermotolerant Bacillus subtilis was studied in solid state fermentation (SSF). The effect of wheat bran (WB) and rice husk (RH) was examined. The appropriate incubation period, moisture level, particle size and inoculum concentration was determined. Maximum yields of 159,520 and 21,760 U g(-1) were achieved by employing WB and RH as substrates in 0.1 M phosphate buffer at pH 7 with 30% initial moisture content at 24 and 48 h. Particle size and inoculum concentration were found to be 1000 pm, 20% and 500 mum, 15% for WB and RH, respectively. Enzyme yield was 7.3-fold higher with WB medium compared with RH. (C) 2002 Elsevier Science Ltd. All rights reserved.