Nitrogen Application in Winter Wheat Grown in Mediterranean Conditions: Effects on Nitrogen Uptake,Utilization Efficiency,and Soil Nitrogen Deficit

ABSTRACT

Nitrogen (N) is one of the most growth restricting nutrients in cereal grain and represents one of the highest input costs in agricultural systems; therefore, environmental and economic considerations require the effective use of N fertilizer in plant production. This study was conducted for three years to better understand wheat plant response to optimize N fertilizer and how to reduce the risk of ground water pollution.

Two of the most important durum wheat cultivars in Southern Italy and four N fertilization levels (0, 60, 120, and 180 kg N ha^{? 1}, indicated as N0, N60, N120, and N180, respectively) were compared in this experiment. During plant growth, fresh and dry matter, plant nutritional state (SPAD readings and stem nitrate content), and N uptake were determined. At harvest, plant N content, N uptake, grain yield, yield components and quality were determined, allowing the calculation of the pre- and postanthesis N uptake and the N utilization efficiency indices. Furthermore, at the beginning and at the end of each year, soil mineral N was measured to calculate mineral N deficit in the soil.

The results indicated that the treatment with 120 kg N ha^{? 1} of fertilizer ensures a good balance between yield and N utilization. In fact, N180 and N120 showed similar yield (3.01 and 3.07 t ha^{? 1}, respectively) and protein content (13.7 and 13.5 %). Meanwhile, throughout the three-year experiment, N180 presented the highest final mineral N content in the soil at the end of the cropping cycles, increasing the amount of N available for leaching. The N120 treatment showed the same values of N utilization indices as compared to N180, indicating that further doses of N fertilizer did not increase wheat N utilization. Plant N status shows that it is possible to modify the N fertilization to reach its optimum level during plant growth, in accordance with variable weather conditions, and consequently the plants requirements. The mean treatments of the preanthesis N uptake were about 67.5% of the total N uptake, and it was significantly and positively correlated with wheat yield. On the contrary, the postanthesis N uptake showed positive correlation with grain protein content, confirming the importance of late N supply in grains quality. The variation of weather conditions affected winter wheat yield, quality, N utilization and plant N status, but any difference throughout years was found between N180 and N120, confirming that higher N rate did not influence wheat growth, yield, and N uptake.     

Mixed Function Oxidase Activity and Organochlorine Levels in Farmed Sharpsnout Seabream (Diplodus puntazzo) from Two Intensive Aquaculture Facilities

Mixed function oxidase (MFO) activities and organochlorine levels were investigated in liver of farmed sharpsnout seabream bred in two intensive facilities, a sea farm and a land-based farm. The aim of this study is to investigate how different facility locations and breeding conditions might affect fish metabolic capabilities and accumulation of toxic chemicals in farmed sharpsnout seabream. The differences between breeding two or more fish species in the same cage or tank known as polyculture, and monoculture (1 species) were also investigated. The results showed that both facility location (sea and land) as well as breeding systems (polyculture and monoculture) might be responsible for the differences observed in both MFO enzyme activity and organochlorine levels. Significantly higher activities of two metabolizing enzymes such as 7-ethoxyresorufin-O-deethylase (EROD) and benzo(a)pyrene monooxygenase (B(a)PMO) were in fact recorded in land-based farmed fish than in sea farmed ones, and much higher in those from polyculture than in monoculture (p < 0.05). By contrast, the highest levels of dichlorodiphenyldichloroethilene (pp′DDE) and polychlorinated biphenyls (PCBs as Aroclor 1260) were measured in sea-farmed fish, except for hexachlorobenzene (HCB), which gave higher levels in land-based farmed fishes. No significant differences were observed between monoculture and polyculture in p,p′DDE and PCBs levels except for p,p′DDE which was significantly higher in monoculture than in polyculture (p < 0.05) in fish reared in tanks. Finally significantly higher HCB levels were measured in fish reared in monoculture in tanks (p < 0.05) and in polyculture in cages (p < 0.05). The low TEQ values obtained for PCB congeners at liver level indicated no concern for fish health.     

Antibodies to soluble liver antigen and α-enolase in patients with autoimmune hepatitis

BACKGROUND: Antibodies to a cytosolic soluble liver antigen (SLA) are specifically detected in patients with autoimmune hepatitis (AIH). The target of anti-SLA has been identified as a ~50 kDa UGA serine tRNA-associated protein complex (tRNP(Ser)Sec), through the screening of cDNA libraries. A recent report questioned the identity of tRNP(Ser)Sec as the real SLA antigen. The latter study identified alpha-enolase as a major anti-SLA target, through proteomic analysis. METHODS: In an attempt to explain the observed discrepancy we have investigated reactivity of SLA positive sera against alpha-enolase and tRNP(Ser)Sec using rat and primate liver homogenate and the recombinant antigens. Thirty-three serum samples, 11 from SLA-positive patients and 22 from SLA negative controls were investigated. SLA antibodies were detected by an inhibition ELISA and confirmed by immunoblot using human liver homogenate. Autoantibody reactivity was further evaluated using preparations of primate and rat liver homogenates. Anti-alpha-enolase antibody reactivity has been tested by immunoblot using recombinant alpha-enolase. An affinity purified goat polyclonal anti-alpha-enolase IgG antibody was used as reference serum sample. Anti-tRNP(Ser)Sec antibody reactivity was detected by ELISA or dot blot using recombinant tRNP(Ser)Sec antigen. RESULTS AND DISCUSSION: The affinity purified IgG antibody directed to human alpha-enolase gave a band of approximately 48 kDa in both human and rat liver homogenates. A high titre anti-tRNP(Ser)Sec antibody serum gave a single band of ~50 kDa in both liver preparations. All but one anti-SLA antibody positive sera reacted with a ~50 kDa but none immunofixed a 48 kDa band. All anti-SLA antibody positive sera reacted strongly with the recombinant full length tRNP(Ser)Sec protein. None of the anti-SLA negative sera reacted with tRNP(Ser)Sec. Anti-SLA positive, and anti-SLA negative sera reacted equally against recombinant alpha-enolase by immunoblot. Pre-incubation of anti-SLA positive sera with tRNP(Ser)Sec completely abolished the 50 kDa band. The findings of the present study indicate that alpha-enolase and tRNP(Ser)Sec are both expressed in primate and rat liver and have a respective MW of 48 and 50 kDa. They also show that anti-tRNP(Ser)Sec - but not anti-alpha-enolase - correlates with anti-SLA antibody reactivity. CONCLUSION: Our findings indicate that tRNP(Ser)Sec is the most likely target of anti-SLA.     

Immunoproteomic analysis of the protective response obtained with subunit and commercial vaccines against Glässer's disease in pigs

An immunoproteomic analysis of the protective response of subunit and commercial vaccines in colostrum-deprived pigs against Glässer's disease was carried out. A mixture of proteins with affinity to porcine transferrin (PAPT) from Haemophilus parasuis Nagasaki strain (serovar 5) was inoculated intramuscularly (PAPT_M) and intratracheally (PAPT_Cp), along with a commercial bacterin. PAPT were separated using 2 dimensional electrophoresis (2DE) gels and with them, 2DE Western blots were carried out. A total of 17 spots were identified as positive with sera of pigs from any of the three vaccinated groups, the highest number of immunoreactive proteins being detected in those having received PAPT_Cp. Among them, six proteins (FKBP-type peptidyl-prolyl cis-trans isomerase, neuraminidase exo-α-sialidase, xanthine-guanine phosphoribosyl transferase, CMP-N-acetylneuraminic acid synthetase, phenylalanyl-tRNA synthetase and glyceraldehyde 3-phosphate dehydrogenase) were found to be novel immunogens in H. parasuis. These proteins showed a high potential as candidates in future subunit vaccines against Glässer's disease. The three experimental groups developed specific systemic total IgG (IgGt), IgG1, IgG2 and IgM antibodies after immunizations. In addition, those receiving PAPT_Cp yielded a serum IgA response.     

Repellent activity of plant-derived compounds against Amblyomma cajennense (Acari: Ixodidae) nymphs

Repellence responses of Amblyomma cajennense nymphs to callicarpenal, intermedeol, Hyptis suaveolens essential oil, extract of Melia azedarach, Cymbopogon nardus, Spiranthera odoratissima, Chenopodium ambrosioides, Ageratum conyzoides, Mentha pulegium, Ruta graveolens, and Memora nodosa were studied. Among these the extract of C. nardus stood out because of the long-lasting repellence, maintaining, in the highest concentration, 35 h of protection against 90% of the nymphs. The essential oil of H. suaveolens and the extracts of C. ambrosioides and A. conyzoides showed good repellence index (66%) when applied in high concentrations. However, greater protection could be obtained at higher concentrations but with a shorter repellence time. Callicarpenal, intermedeol, extract of M. Pulegium, and M. nodosa leaves showed moderate repellence in high concentrations. Extracts from M. azedarach, R. graveolens, S. odoratissima, and M. nodosa roots showed little or no repellent effect. These results show that some plant extracts may represent a promising alternative in the control of infestations by A. cajennense.     

Tests for outdoor window profiles: 90° mortise tenon corner joints strength assessment

The research focuses on the assessment of the performances of glued laminated wood corner joints for outdoor window profiles applications, proposing a methodology to appreciate the strength of 90° tenon mortise corner joints. The rationale relies on the potential damage (i.e. breaking of the frame) that can be caused by poor glueing processes and/or typology of adhesives. There is a number of standards for assessment of wood-adhesive bonds for outdoor windows; however, there is a lack of specific standards related to glueing assessment for outdoor wood frames, which can take into account all the factors influencing the glueing quality. The proposed methodology was tested on red oak window profiles. A commercially available polyvinyl acetate-based adhesive was used for corner joints. Bending strength of 90° tenon mortise corner joints was measured and compared with maximum admissible loads on the frame to limit its deformations within admissible ranges. The test results show that the 90° tenon mortise corner joints strength exceeds the admissible load to preserve the functionality of the frame. In order to appreciate the influence of conditioning processes on adhesion, shear strength tests of the flatwise glued joint samples (bond lines of lamellae) were carried out after different conditioning processes.     

Evaluation of an open portable chamber system for measuring cover crop water use in a vineyard and comparison with a mini-lysimeter approach

Cover crops are largely used in viticultural areas because of the many positive agronomic and environmental benefits they provide. However, there is insufficient data describing the amount of water they use. A portable chamber used as an open measurement system and its suitability to measure the cover crop evapotranspiration (E) in a vineyard are described in this study. The performance of the chamber was tested by a calibration experiment (R² = 0.97). The lowest air flow rate used (9.2 l s⁻¹) was found to be suitable to limit the chamber from overheating beyond 3.1 K above the outside temperature. Furthermore, an experiment was designed to compare the daily cover crop (Festuca arundinacea var. barfelix) water use measured by the chamber system with measurements using a mini-lysimeter (ML) method and with estimates using the FAO-56 PM equation (Eo). The experiment was carried out in one inter row of a vineyard over the course of 4 days following an irrigation event. Although the field experiment was limited to 4 days, the results obtained together with the calibration trials support the possibility of the chamber being a useful tool for measuring the cover crop E. The ability of the MLs to represent the water use of the cover crop in the rest of the vineyard was limited to the first two days of the experiment, after which time the soil water content inside the containers was significantly (p = 0.007, p = 0.03) lower than in the surrounding field.     

Concentration of Bioactive Compounds from Elderberry (<Emphasis Type="Italic">Sambucus nigra</Emphasis> L.) Juice by Nanofiltration Membranes

For the first time the chemical profile, physico-chemical parameters, inhibition of carbohydrate hydrolysing enzymes associated with type 2 diabetes, and radical scavenging properties of Sambucus nigra L. (elderberry) juice treated by nanofiltration (NF) were investigated. Three commercial NF membranes with different molecular weight cut-off (MWCO) (400 and 1000 Da) and polymeric material (composite fluoro-polymer and polyethersulphone) were tested. According to HPLC analyses, most part of bioactive compounds were retained by the NF membranes producing a retentate fraction of interest for the production of functional foods. The NP030 membrane, a polyethersulphone membrane with a MWCO of 400 Da, exhibited the highest rejection towards phenolic compounds when compared with the other selected membranes. Accordingly, the produced retentate fractions exhibited the highest radical scavenging activity.