Neslihan Dikbas

Control of Aspergillus flavus with essential oil and methanol extract of Satureja hortensis.

The essential oil and methanol extract of Satureja hortensis were tested for antifungal activity against Aspergillus flavus in vitro on Petri plates and liquid culture, and under storage conditions. The oil showed strong antifungal activity based on the inhibition zone and minimal inhibitory concentration values against the pathogen on Petri plates assays. The very low concentrations of them also reduced wet and dry mycelium weight of pathogen fungus in liquid culture. When the oils at 25, 12.5 and 6.25 microl/mL concentrations were applied to lemon fruits before seven days of pathogen inoculation on storage conditions, the decay on fruits caused by the pathogen could be prevented completely. The results in this study showed that the essential oil of S. hortensis had strong antifungal activity against pathogen fungi tested. So, the essential oil of S. hortensis could be used for management of this pathogen as a potential source of sustainable eco-friendly botanical fungicides.

Antibacterial activities of essential oils and extracts of Turkish Achillea, Satureja and Thymus species against plant pathogenic bacteria

BACKGROUND The aims of this study were to examine the chemical composition of the essential oils and hexane extracts of the aerial parts of Satureja spicigera (C. Koch) Boiss., Thymus fallax Fisch. & CA Mey, Achillea biebersteinii Afan, and Achillea millefolium L. by GC and GC-MS, and to test antibacterial efficacy of essential oils and n-hexane, chloroform, acetone and methanol extracts as an antibacterial and seed disinfectant against 25 agricultural plant pathogens. RESULTS Thymol, carvacrol, p-cymene, thymol methyl ether and gamma-terpinene were the main constituents of S. spicigera and T. fallax oils and hexane extracts. The main components of the oil of Achillea millefolium were 1,8-cineole, delta-cadinol and caryophyllene oxide, whereas the hexane extract of this species contained mainly n-hexacosane, n-tricosane and n-heneicosane. The oils and hexane extracts of S. spicigera and T. fallax exhibited potent antibacterial activity over a broad spectrum against 25 phytopathogenic bacterial strains. Carvacrol and thymol, the major constituents of S. spicigera and T. fallax oils, also showed potent antibacterial effect against the bacteria tested. The oils of Achillea species showed weak antibacterial activity. Our results also revealed that the essential oil of S. spicigera, thymol and carvacrol could be used as potential disinfection agents against seed-borne bacteria. CONCLUSION Our results demonstrate that S. spicigera, T. fallax oils, carvacrol and thymol could become potentials for controlling certain important agricultural plant pathogenic bacteria and seed disinfectant.

Purification, characterization of phytase enzyme from Lactobacillus plantarum bacteria and determination of its kinetic properties

Phytases (myo-inositol hexakisphosphate phosphohydrolase, EC 3.1.3.8) catalyze the release of phosphate from phytates. Many of the cereal grains, legumes and oilseeds store phosphorus in phytate form. Phytases can be produced by plants, animals and microorganisms. However, the ones with microbial origin are the most promising for commercial uses and biotechnological applications. In this study, phytase enzyme isolation from Lactobacillus spp. ATCC strain and its characterization was carried out. Phytase production from bacterial strains was determined by zone production formed around colonies after 48 h of incubation at 30°C in MRS medium. Optimum pH and optimum temperature values of the phytase enzyme that was partially purified by precipitation of ammonium sulphate from Lactobacillus plantarum , extracellularly from bacteria put into liquid culture medium, were measured. Optimum activity of the enzyme derived from L. plantarum bacterium was at 30°C and pH 6.0. It was observed that L. plantarum s extracellular enzyme maintains its 90% of activity at 10-100°C for 120 min. Effects of certain metal ions on activity of phytase enzyme derived from L. plantarum were also investigated. Of these, CuCl 2 , MnCl 2 , CoCl 2 , CaCl 2 and ZnCl 2 decreased enzyme activity significantly. FeCl 2 increased enzyme activity by 121%. Based on these results, the phytase enzyme of L. plantarum is considered suitable for use in many industrial areas, in feed and food industries in particular, due to its thermal stability and resistance to metal ions. Keywords: Purification, characterization, phytase, Lactobacillus plantarum . African Journal of Biotechnology , Vol 13(23) 2373-2378

Influence of Summer Savory Essential Oil (Satureja hortensis) on Decay of Strawberry and Grape

Abstract The essential oil isolated from the aerial parts of wild Turkish Satureja hortensis L. (summer savory) was analyzed by GC-MS, and carvacrol (54.7 %), y-terpinene (20.9 %), p-cymene (12.3 %), a-terpinene (2.0 %), and thymol (2.0 %) were found to be major components of the oil. Post-harvest decay of fruits caused by some fungi is still a most important problem and causes major crop losses during storage and shipment. High relative humidity during storage and marketing conditions accelerate development of fungal disease and decay of the grapes. The six different concentrations of the oil (0.01, 0.02, 0.04, 0.11, 0.22 and 0.45 µL/cm3) were tested for their effectiveness in reducing decay of strawberry and grape fruits at three storage temperature (5, 10 and 20°C). The oil tested reduced decay of strawberry and grape fruits compared to controls, in particularly at low temperatures (5 and 10°C). Decay reducing effect of the oil on strawberry and grape fruits increased with increase in doses of the oil. However, microbial development in the fruits increased with increase in temperature. Nevertheless, the present results showed that S. hortensis essential oil has a significant reducing effect on the decay of strawberry and grape fruits during storage at low temperatures. Therefore, the essential oil of summer savory may be a potential source of alternative fungicides to protect strawberry and grape fruits as well as other stored products from pathogens and saprophytes.

Paraoxonase-2 and paraoxonase-3: comparison of mRNA expressions in the placentae of unexplained intrauterine growth restricted and noncomplicated pregnancies

Abstract Objective: Recent evidence suggests that oxidative stress is involved in the pathophysiology of many human diseases. It has been demonstrated that oxidative stress is associated with intrauterine growth restriction (IUGR), and the depletion of placental antioxidant systems has been suggested as a key factor in this disease. Our aims were to explore the possible role of antioxidant paraoxonase-2 (PON2) and paraoxonase-3 (PON3) in the pathophysiology of unexplained IUGR. Methods: We have studied the expression of mRNA for PON2, PON3 in placental tissues by using RT-qPCR. Two groups, consisting of normal (n = 18) and unexplained IUGR pregnancies (n = 20) were compared. Results: Our results demonstrated that there were no significant differences in the mRNA expressions of PON2, PON3 between the two groups (p = 0.28, p = 0.90, respectively). PON2 and PON3 were down-regulated in IUGR. Antenatal steroid therapy had no effect on the expression mRNA in placentae of unexplained IUGR pregnancies compared to non-treated group. Conclusions: These results suggest that PON2, PON3 mRNA levels were not changed significantly in placentae of IUGR when compared to normal pregnant women.

Phytase from Weissella halotolerans: purification, partial characterisation and the effect of some metals

ABSTRACT In the study, phytase was purified in three simple steps comprising ammonium sulphate precipitation, anion exchange and gel filtration chromatography from Weissella halotolerans. The enzyme was obtained with a specific activity of 227.73 EU/mg and 6.52% recovery. The molecular mass of the enzyme was determined to be 41.52 kDa. The optimum pH and temperature for the enzyme were 6.0 and 50°C, respectively. Furthermore, the effects of metal ions on the enzyme were investigated. Ag+, Zn2+, Cr2+ and Fe2+ ions inhibited phytase by 21.86, 25.63, 32.82 and 90.43%, respectively, whereas Co2+, Cu2+, Pb2+, Cd2+ ve Mn2+ ions increased the enzyme activity.

Low transcriptional activity of PON2 in recurrent abortion: A novel therapeutic agent?

OBJECTIVE Oxidative stress has been reported to be associated with various pregnancy complications and to play key roles in many of them. An inadequate level of antioxidant defense may eventually lead to an early pregnancy loss. There is a lack of information about the roles of the PON2 and PON3 enzymes in the etiology of the cases of unexplained recurrent abortus. The aim of our study is to determine and present the data regarding the roles of these enzymes for the first time. MATERIALS AND METHODS We measured the transcriptional levels of the PON2 and PON3 enzymes in the curettage materials obtained from the patients with unexplained recurrent abortus (n=25) and compared the results with those measured in the abortus materials from healthy pregnant women (n=50) who had undergone a voluntary abortion. The transcriptional activities of PON2 and PON3 enzymes were measured through quantification of their respective mRNAs by RT-qPCR assay. For each gene, 2-ΔCt replication values of the control and the patient groups were compared using the Students t-test, and the p values were calculated thereafter. Fold-changes in the enzyme transcription levels were interpreted as up- or down-regulation. RESULTS PON2 mRNA expressions were found to be highly decreased in the patient group (p=0.000002). PON3 transcription, when compared to the healthy pregnant women, was found to be down-regulated in the patient group; however, the difference was not statistically significant (p=0.69). CONCLUSIONS In this study, we evaluated the expressional regulation of the PON2 and PON3 enzymes in unexplained recurrent abortus. Our results demonstrate for the first time that the expressions of PON2 and PON3 are down-regulated in the abortion specimens of the patients with recurrent miscarriage. Although both enzymes had low expression levels, the decrease in the transcriptional activity of PON2 revealed a high statistical significance. According to these results, it is rational to speculate that PON2 may be a novel therapeutic agent in the management of the cases with unexplained recurrent abortion.

Effect of essential oil of Origanum rotundifolium on some plant pathogenic bacteria, seed germination and plant growth of tomato

The aim of this study is to determine effect of Origanum rotundifolium’s essential oil on some plant pathogenic bacterias, seed germination and plant growth of tomato. Xanthomonas axanopodis pv. vesicatoria strain (Xcv-761) and Clavibacter michiganensis ssp. michiganensis strain (Cmm) inoculated to tomato seed. The seeds were tested for germination in vitro and disease severity and some plant growth parameters in vivo. In vitro assay, maximum seed germination was observed at 62,5 µl/ml essential oil treatment in seeds inoculated with Xcv-761 and at 62,5 µl/ml essential oil and streptomycin treatment in seeds inoculated with Cmm. The least infected cotiledon number was observed at 500 µg/ml streptomycin treatment in seeds inoculated with Cmm. In vivo assay, maximum seed germination was observed at 250 µl/ml essential oil teratment in tomato inoculated with Cmm. Lowest disease severity, is seen in the CMM infected seeds with 250 µl/ml essential oil application these results were statistically significant wh...