Rapid shift from denitrification to nitrification in soil after biogas residue application as indicated by nitrous oxide isotopomers

Nitrous oxide (N₂O) is one of the major greenhouse gases emitted from soils, where it is mainly produced by nitrification and denitrification. It is well known that rates of N₂O release from soils are mainly determined by the availability of substrates and oxygen, but N₂O source apportioning, highly needed to advance N₂O mitigation strategies, still remains challenging. In this study, using an automated soil incubation system, the N₂O site preference, i.e. the intramolecular ¹⁵N distribution, was analyzed to evaluate the progression in N₂O source processes following organic soil amendment. Biogas fermentation residue (BGR; originating from food waste fermentation) was applied to repacked grassland soil cores and compared to ammonium sulfate (AS) application, both at rates equivalent to 160 kg NH₄⁺-N ha⁻¹, and to unamended soil (control). The soil cores were incubated in a helium-oxygen atmosphere with 20 kPa O₂ for 43 days at 80% water-filled pore space. 43-day cumulative N₂O emissions were highest with BGR treated soil accounting for about 1.68 kg N₂O-N ha⁻¹ while application of AS caused much lower fluxes of c. 0.23 kg N₂O-N ha⁻¹. Also, after BGR application, carbon dioxide (CO₂) fluxes showed a pronounced initial peak with steep decline until day 21 whereas with ammonium addition they remained at the background level. N₂O dual isotope and isotopomer analysis of gas samples collected from BGR treated soil indicated bacterial denitrification to be the main N₂O generating process during the first three weeks when high CO₂ fluxes signified high carbon availability. In contrast, in the second half after all added labile carbon substrates had been consumed, nitrification, i.e. the generation of N₂O via oxidation of hydroxylamine, gained in importance reaching roughly the same N₂O production rate compared to bacterial denitrification as indicated by N₂O SP. Overall in this study, bacterial denitrification seemed to be the main N₂O forming process after application of biogas residues and fluxes were mainly driven by available organic carbon.     

Effect of synthetic nano-hydroxyapatite as an alternative phosphorus source on growth and phosphorus nutrition of lettuce (Lactuca sativa L.) plant

Phosphorus (P) is one of the least available mineral nutrients to the plants in calcareous and alkaline soils. In this study, we investigated the synthesis, characterization and use of synthetic nano-hydroxyapatite (NHA), P uptake by plants as well as its residual effects. Soluble P source (H₃PO₄) was also included as treatment for comparison. NHA prepared by wet chemical techniques, characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and elemental dispersive X-ray (EDX) analysis. NHA and H₃PO₄ were applied at a rate of 200 mg kg^?1 to find out their effects on phosphorus nutrition and growth of lettuce on the low and high calcareous soil. In addition to this, residual effects of NHA and H₃PO₄ were also determined for lettuce plants grown after first lettuce plants in the both soil. Dry weights of the first and second lettuce plants grown in low and high calcareous soil were significantly increased by applied phosphorus regardless of the source. NHA seems to be more effective than that of ordinary phosphorus source (H₃PO₄-P) on growth and P concentration of the lettuce plants. The promising results of this study needs to be supported with long term field studies regarding the uptake, translocation and interactions of nano-P with the other elements.     

A comparative study on the prevalence of Theileria equi and Babesia caballi infections in horse sub-populations in Turkey

Blood and serum samples were taken from 481 horses, from a stud farm or a racecourse, and tested by microscopic examination of blood smears and cELISA for Theileria equi (T. equi) and Babesia caballi (B. caballi) infections. At the time of sampling, animals were also examined for tick infestations and clinical disease, which were not observed in any of the sampled horses. During the microscopic examination of thin blood smears, parasites were detected in the three horses from the racecourse. Overall seroprevalence of infection was detected as 18.50% (89 of 481 horses) by cELISA, with T. equi being significantly more prevalent than B. caballi. Of the 481 blood samples, 78 (16.21%) were serologically positive for T. equi and 4 (0.83%) were serologically positive for B. caballi. In addition, 7 (1.46%) samples were positive for both T. equi and B. caballi antibodies. Seropositivity rates in the racecourse horses were higher than those determined in the stud farm horses. The rates for T. equi, B. caballi and both species were 13.39, 0.52 and 0% in the horses from the stud farm and 27, 2 and 7% in the racecourse horses, respectively. These results indicate that equine piroplasmosis is more common in racehorses than studhorses and therefore it might be a serious concern in horses that participate to international races.     

Determination of the relationship between serum anti‐Müllerian hormone level and superovulatory response in Simmental cows

The most significant focal points of the embryo transfer technology are as follows: the selection of donors, the response of the selected donor to the superovulation protocol and the obtained number of the transferable embryos. For this purpose, it is suggested that donor selection can be done by anti‐Müllerian hormone (AMH) levels, and embryo production is evaluated. AMH is secreted by the granulosa cells of primordial, pre‐antral and antral follicles below 4 mm in the ovary, independent of FSH. Therefore, the aim of this study was to investigate the relationship between serum AMH levels and the number of corpus luteum (CL), total embryos and transferable embryos that were shaped after a uniform superovulation protocol. For this reason, 48 Simmental cows, which were located at General Directory of Agricultural Enterprises (region, province, etc. instead of the general directorate), were used as donors for the embryo transfer. Blood samples were taken at random, regardless of the stage of animal's sexual cycle. AMH levels were measured by enzyme‐linked fluorescent assay (ELFA) method of the miniVIDAS^® (bioMérieux SA) using AMH Bovine Test Kit. According to the statistical analyses of the obtained data, AMH levels were positively correlated with CL and total embryos (p < .05). No significant correlations between AMH and transferable embryos were approved (p > .05). It was also determined that each 200 pg/ml increase in serum AMH level resulted in one increase in CL number. Overall, considering the positive correlation between AMH level and the obtained number of CL and total embryos after a superovulation treatment, it was concluded that measuring blood AMH level prior to any further costly implementation may be an effective method in donor selection.     

Vegetative compatibility and pathogenicity of <Emphasis Type="Italic">Verticillium dahliae</Emphasis> isolates from chrysanthemum in Turkey

A collection of 30 strains of Verticillium dahliae, recovered during 2004–2006 from 12 cultivars of chrysanthemum (Chrysanthemum morifolium) in five districts of İzmir province in Turkey, was assigned to vegetative compatibility groups (VCGs) based on pairings of complementary nitrate-nonutilizing (nit) mutants induced on a chlorate-containing medium. Of these strains, nine were assigned to VCG1, seven to VCG2A, 11 toVCG2B and one to VCG4B. The remaining two strains could not be tested for vegetative compatibility because of their inability to yield nit mutants. Pathogenicity tests conducted by the root-dip method, demonstrated that wilt of chrysanthemum in Turkey is caused by V. dahliae, and most strains in VCG1 were significantly more aggressive to chrysanthemum than those in VCGs 2 and 4B. This is the first known study in the world of the VCGs of V. dahliae isolates from chrysanthemum.     

Screening for resistance of Turkish olive cultivars and clonal rootstocks to Verticillium wilt

Verticillium wilt resistance of 77 olive cultivars including 71 domestic and six foreign ones, and four clonal rootstocks available in the olive gene bank, were tested using a highly virulent isolate (D pathotype) of Verticillium dahliae. The pathogen was stem-inoculated into the own-rooted saplings. Most cultivars and rootstocks were found to be extremely susceptible to the disease. ‘Sinop No. 1’, ‘E?riburun Nizip’, ‘Erkence’, ‘E?riburun Tatayn’, ‘Girit Zeytini’ and ‘Marantelli’ were highly resistant, as their disease severities did not exceed 10%. Additionally, 11 domestic cultivars (‘Sar? Habe?i’, ‘Ya?l?k Çelebi’, ‘Zoncuk’, ‘Dilmit’, ‘?am’, ‘Hurma Karaca’, ‘Erdek Ya?l?k’, ‘Melkabaz?’, ‘Yün Çelebi’, ‘Kan Çelebi’ and ‘Siyah Salamural?k’), two foreign cultivars (‘Arbequina’ and ‘Frantoio’) and one wild clonal rootstock (‘D36’) were found to be resistant, with disease severities less than 30%. On the other hand, the moderately susceptible group comprised ten domestic cultivars (‘Ak Zeytin’, ‘Ya? Çelebi’, ‘Saurani’, ‘Butko’, ‘Gemlik’, ‘Otur’, ‘Ya? Zeytini’, ‘Belluti’, ‘Sinop No. 2’ and ‘Samanl?’), three foreign cultivars (‘Leccino’, ‘Chemlali’ and ‘Ascolana’) and one wild clonal rootstock (‘D9’). The number of cultivars within highly resistant and resistant groups was 17 out of the 71 domestic cultivars from all regions (four from Aegean, seven from southeastern Anatolia, two from Black Sea and three from Marmara).     

Estimation of the effect of <Emphasis Type="Italic">Tomato spotted wilt virus</Emphasis> (TSWV) infection on some yield components of tomato

The effects of Tomato spotted wilt virus (TSWV) on yield and quality of tomato fruits were studied from May through November of 2004 at the Experimental Field of the Agricultural Faculty of Ondokuz Mayis University, in Samsun province, Turkey. TSWV caused 42.1% and 95.5% reduction in yield and marketable value of tomato, respectively. TSWV infection in tomato crop caused significant (P < 0.05) reductions in weight, total number, width and length of the fruits in infected plants. Reductions in yield-contributing parameters were 26.61% in weight, 20.18% in number, 10.94% in width and 11.93% in length of fruits. It is difficult to estimate the actual yield loss and influence levels of TSWV in the field. Economic data are scarce, but in the present study it was estimated that the yield loss due to TSWV in tomatoes was approximately $0.9 million in Samsun, Turkey.     

Degradation of chlorophenoxyacid herbicides in aqueous media,using a novel electrochemical method†

The degradation of five chlorophenoxyacid herbicides has been studied using an electrochemical method based on the Fenton reaction (simultaneous reduction of dioxygen and ferric ions). The method consists of electrosynthesizing OH^· radicals, which react rapidly with chlorophenoxyacids in aqueous media. HPLC and GC-MS analysis show the formation of polyhydroxyphenols and quinones in a first step, and the complete destruction of the aromatic nucleus upon exhaustive electrolysis. This offers a possible way for the depollution of natural waters containing chlorophenoxyacid pesticide residues. © 1999 Society of Chemical Industry.     

Effects of vitamin E and selenium on tissue bio-element status in organophosphate toxicity of rats

The present study was designed to investigate the effects of vitamin E (vit E), selenium (Se) and vit E + Se against organophosphate (OP) toxicity in tissues’ trace and major element levels and erythrocyte antioxidant enzyme activities of rats. Trace and major element concentrations in the tissues were measured by inductively coupled plasma-optical emission spectroscopy. Erythrocyte antioxidant enzyme activities were studied by using spectrophotometer. Antioxidant enzyme activities such as superoxide dismutase, glutathione peroxidase and catalase increased in the fenthion-treated groups (control) more than that of sham group subjects. Heart and pectoral muscle tissue Se and Zn concentrations in the control group were higher than sham group. However, jejunum, kidney, liver and pancreas Se and Zn concentrations in the control group were found to be lower than those in the sham group. The Mn concentrations in the all of the tissues were lower in the control group when compared with the sham group. Brain, heart, jejunum, kidney and pancreas Fe concentrations and heart, jejunum, liver, pectoral muscle and pancreas Cu concentrations were found to be lower in the control group. The treatment of vit E, Se and vit E + Se were increased bio-element levels in the many tissue. In conclusion, the results of the present study demonstrate that the tissue trace and major element concentrations and enzymatic antioxidant system were significantly affected OP toxicity. Furthermore, we have shown an association between bio-elements and antioxidant enzymes in OP toxicity. In addition, administration of vit E, Se and vit E + Se might regulate some trace and major element levels in the many tissues.     

Protective effects of caffeic acid phenethyl ester on rotenone-induced myocardial oxidative injury

Rotenone, an insecticide, causes toxicity through inhibition of mitochondrial electron transport chain at complex I and oxidative injury to the tissues. The aim of the present study was to determine in vivo effects of rotenone on myocardium and cardio-protective effects of caffeic acid phenethyl ester (CAPE), an antioxidant agent, against rotenone toxicity in rats. The rats were divided into three groups: untreated control, rotenone (2.5 mg/kg/day for 60 days, i.p.) and rotenone + CAPE groups. CAPE was administrated i.p. 10 μmol/kg/day for 62 days started two days before first dose rotenone injection. The malondialdehyde, nitric oxide levels and xanthine oxidase activity of rotenone group was significantly higher than control and rotenone + CAPE groups (p < 0.05). However, catalase activity in the rotenone group was decreased in comparison with the other groups (p < 0.05). The superoxide dismutase activity of rotenone group was insignificantly decreased compared to the others. In conclusion, rotenone caused lipid peroxidation in myocardial tissue and CAPE treatment prevented this rotenone-induced lipid peroxidation in rats. CAPE might be a cardio-protective agent against myocardial toxicities.