Volatile fractions from three cultivars of Olea europaea L. collected in two different seasons

The chemical composition of the volatile fractions from leaves of three Olea europaea L. cultivars (Leccino, Frantoio, and Cipressino) harvested at two different times of the year were examined by GC and GC-MS. The results showed a high content of aliphatic aldehydes in the three cultivars during both harvesting periods and an increase of (E)-2-hexenal (an aldehyde with high antimicrobial properties) percentage from July to November.     

C and N in soil organic matter density fractions under elevated atmospheric CO2: Turnover vs. stabilization

Turnover of C and N in an arable soil under Free Air Carbon Dioxide (FACE) experiment was studied by the use of ¹³C natural abundance and ¹⁵N-labeled fertilizers. Wheat was kept four growing seasons under ambient and elevated CO₂ concentrations and fertilized for three growing seasons. Density fractionation of soil organic matter (SOM) allowed to track ¹³C and ¹⁵N in free particulate organic matter (fPOM; <1.6 g cm⁻³), particulate organic matter occluded within aggregates with two densities (oPOM 1.6, oPOM 1.6-2.0 g cm⁻³), and in mineral-associated organic matter (>2.0 g cm⁻³) fractions. Elevated CO₂ and N fertilization did not significantly affect C and N contents in the bulk soil. Calculated mean residence time (MRT) of C and N revealed the qualitative differences of SOM density fractions: (i) the shortest MRT_C and MRT_N in fPOM confirmed high availability of this fraction to decomposition. Larger C/N ratio of fPOM under elevated vs. ambient CO₂ indicated an increasing recalcitrance of FACE-derived plant residues. (ii) There was no difference in MRT of C and N between lighter and heavier oPOMs probably due to short turnover time of soil aggregates which led to oPOM mixing. The increase of MRT_C and MRT_N in both oPOMs during the experiment confirmed the progressive degradation of organic material within aggregates. (iii) Constant turnover rates of C in the mineral fraction neither confirmed nor rejected the assumed stabilization of SOM to take place in the mineral fraction. Moreover, a trend of decreasing of C and N amounts in the Min fraction throughout the experiment was especially pronounced for C under elevated CO₂. Hence, along with the progressive increase of C_FACE in the Min fraction the overall losses of C under elevated CO₂ may occur at the expense of older “pre-FACE” C.     

An analysis of agricultural sustainability of cropping systems in arable and dairy farms in an intensively cultivated plain

In Lombardy region (northern Italy) agricultural systems are mostly based on cereals and forage crops, and are normally intensively cultivated. To monitor and analyse the most important agri-environmental issue of this area (water pollution by nitrates and plant protection products, non-renewable fossil energy exploitation, weed dynamics), we conducted an integrated agronomic, environmental and economic assessment of arable and dairy farming using indicators.The structural and management data about farming and cropping systems were collected by periodic interviews over a 3-year period in seven (three arable and four dairy) representative farms.The nitrogen surplus calculated at field scale ranged from low (27 kg N ha^?1) to high (339 kg N ha^?1) values, depending by the amount of chemical and organic fertilisers applied. Fossil inputs ranged from 11.2 to 46.0 GJ ha^?1; the highest values were due to the high use of machinery and chemical inputs. The efficiency factor in energy transformation (an indicator of the dependence of food and feed production on non-renewable energy) ranged from 5.0 to 12.2. Large variability was also observed for economic performance (gross margin; from -364 to 1078 € ha^?1). The lowest values were observed where the total costs of production (fixed and variable) were elevated. The simplification of cropping systems was responsible for a high probability of weed populations development. The values of Load Index, an indicator describing the potential toxicity of plant protection products on non-target organisms, showed an elevated use of active substances due to the dominance of maize.The indicator-based assessment, founded on a relatively simple data collection procedure, described crop management by combining different aspects into few quantities and highlighted its critical environmental issues. The work represents a starting point for improving cropping system management in the study area; the same procedure could be re-applied if data about improved management scenarios were available.     

Voltammetric assay for the aging of beer

A new method for the evaluation of beer aging, based on a voltammetric analysis of beer distillates, is described. By measuring the current of both acetaldehyde and sulfite voltammetric peaks it is possible to distinguish between fresh, naturally aged, and artificially aged beers. The results obtained for the ratio of acetaldehyde and SO(2) currents correlate well with those given by an expert sensory panel. The kinetics of the combining reaction of sulfite with acetaldehyde was followed for different acetaldehyde/SO(2) molar ratios by using a programmed voltammetric procedure. The formation of an acetaldehyde-sulfite adduct is rapid, and the reaction equilibrium is reached after 30 min, which is in accordance with the results previously obtained by other methods. This voltammetric-based approach seems to be a new attractive tool for detecting chemical equilibria of the addition of sulfite to carbonyls in beer model systems.     

Effect of Astaxanthin on Human Sperm Capacitation

In order to be able to fertilize oocytes, human sperm must undergo a series of morphological and structural alterations, known as capacitation. It has been shown that the production of endogenous sperm reactive oxygen species (ROS) plays a key role in causing cells to undergo a massive acrosome reaction (AR). Astaxanthin (Asta), a photo-protective red pigment belonging to the carotenoid family, is recognized as having anti-oxidant, anti-cancer, anti-diabetic and anti-inflammatory properties and is present in many dietary supplements. This study evaluates the effect of Asta in a capacitating buffer which induces low ROS production and low percentages of acrosome-reacted cells (ARC). Sperm cells were incubated in the presence or absence of increasing concentrations of Asta or diamide (Diam) and analyzed for their ROS production, Tyr-phosphorylation (Tyr-P) pattern and percentages of ARC and non-viable cells (NVC). Results show that Asta ameliorated both sperm head Tyr-P and ARC values without affecting the ROS generation curve, whereas Diam succeeded in enhancing the Tyr-P level but only of the flagellum without increasing ARC values. It is suggested that Asta can be inserted in the membrane and therefore create capacitation-like membrane alteration which allow Tyr-P of the head. Once this has occurred, AR can take place and involves a higher numbers of cells.     

Baseline sensitivity of Monilia yunnanensis to the DMI fungicides tebuconazole and triadimefon

Monilia yunnanensis was recently identified as a new species causing brown rot of peach in China. Sterol 14α-demethylase inhibitors (DMIs) continue to be important in the management of brown rot of Monilinia spp. worldwide. Tebuconazole and triadimefon are two kinds of DMI fungicides that may be used for brown rot control in China. To establish the baseline sensitivity of M. yunnanensis to these two DMI fungicides, 203 M. yunnanensis single spore isolates were collected. Measurements of sensitivity to the two fungicides were based on inhibition of mycelial growth. For both fungicides, the sensitivity distribution was a unimodal curve, with an EC₅₀ range (the effective concentration to inhibit mycelial growth by 50 %) of 0.0001–0.0644 μg/ml for tebuconazole and 0.2311–1.7477 μg/ml for triadimefon. The M. yunnanensis isolates were obtained from orchards where DMI fungicides have not been used for peach brown rot control, thus the fungicide sensitivity distribution established in this study can be considered as the baseline for monitoring the resistance development in M. yunnanensis once the DMI fungicides are used to control peach brown rot.     

Competition between Ascorbate and Glutathione for the Oxidized Form of Methylated Quercetin Metabolites and Analogues: Tamarixetin, 4'O-Methylquercetin, Has the Lowest Thiol Reactivity

Quercetin (Q) is a bioactive compound with excellent antioxidant activity. However, the thiol reactivity of its oxidation product (oxQ) forms a disadvantage. The aim of the present study was to decrease this thiol toxicity. We found that methylated Q metabolites displayed lower thiol reactivity than Q. The most effective was tamarixetin, 4'O-methylquercetin (4'MQ), that has a corresponding oxidation product (ox4'MQ) with thiol reactivity 350 times lower than oxQ. The endogenous metabolism of Q to 4'MQ might be a physiological way to safely benefit from the antioxidant potential of Q in vivo. Our results were explained with Pearson's HSAB concept and corroborated by quantum molecular calculations that revealed a strong correlation between the relative thiol reactivity and the lowest unoccupied molecular orbital (LUMO). The polarity of the molecule and the π-π interaction between the AC- and the B-ring appeared to determine the LUMO and the thiol reactivity of the oxidation product.     

Natural infection with two genotypes of Cryptosporidium in red squirrels (Sciurus vulgaris) in Italy

We investigated the genotypes of Cryptosporidium infecting red squirrels (Sciurus vulgaris L.) in two areas of the Western Alps in Italy. Examination of 141 faecal samples from 70 red squirrels revealed oocysts of Cryptosporidium in 17 animals (24.3%). Based on 18S rRNA gene sequencing, two genotypes of Cryptosporidium species were found: 15 squirrels were positive for the Cryptosporidium ferret genotype and 2 for the Cryptosporidium chipmunk genotype I. The occurrence and intensity of Cryptosporidium infection did not differ between the study areas or sex. More than 85% of the positive animals were adults; however no difference was found between Cryptosporidium infection in the juvenile and adult age groups. Oocysts of the Cryptosporidium ferret genotype measured 5.5 +/- 0.3 x 5.2 +/- 0.2 microm (shape index 1.06) and the Cryptosporidium chipmunk genotype I 5.8 +/- 0.3 x 5.4 +/- 0.3 microm (shape index 1.07). Neonatal and adult CD1 and BABL/c mice inoculated with 1 x 10(3) fresh oocysts of both genotypes did not produce detectable infection.     

Adaptation to fungicides in Monilinia fructicola isolates with different fungicide resistance phenotypes

The ability to develop fungicide resistance was assessed in Monilinia fructicola isolates with different fungicide sensitivity phenotypes by adapting mycelium and conidia to increasing concentrations of selective fungicides and UV mutagenesis. Results showed that adaptation to Quinone outside inhibitor (QoI) fungicide azoxystrobin and sterol demethylation inhibitor (DMI) fungicide propiconazole was more effective in conidial-transfer experiments compared to mycelial-transfer experiments. DMI-resistant (DMI-R) isolates adapted to significantly higher doses of azoxystrobin in both, mycelial- and conidial-transfer experiments compared to benzimidazole-resistant (BZI-R) and sensitive (S) isolates. Adaptation to propiconazole in conidial-transfer experiments was accelerated in BZI-R isolates when a stable, nonlethal dose of 50 microg/ml thiophanate-methyl was added to the selection medium. One of two azoxystrobin-resistant mutants from DMI-R isolates did not show any fitness penalties; the other isolate expired before further tests could be carried out. The viable mutant caused larger lesions on detached peach fruit sprayed with azoxystrobin compared to the parental isolate. The azoxystrobin sensitivity of the viable mutant returned to baseline levels after the mutant was transferred to unamended medium. However, azoxystrobin resistance recovered quicker in the mutant compared to the corresponding parental isolate after renewed subculturing on medium amended with 0.2 and 1 microg/ml azoxystrobin; only the mutant but not the parental isolate was able to adapt to 5 microg/ml azoxystrobin. In UV mutagenesis experiments, the DMI-R isolates produced significantly more mutants compared to S isolates. All of the UV-induced mutants showed stable fungicide resistance with little fitness penalty. This study indicates the potential for QoI fungicide resistance development in M. fructicola in the absence of a mutagen and provides evidence for increased mutability and predisposition to accelerated adaptation to azoxystrobin in M. fructicola isolates resistant to DMI fungicides.     

Seasonal variation of red clover (Trifolium pratense L., Fabaceae) isoflavones and estrogenic activity

Red clover (Trifolium pratense L., Fabaceae) dietary supplements are currently used to treat menopausal symptoms because of their high content of the mildly estrogenic isoflavones daidzein, genistein, formononetin, and biochanin A. These compounds are estrogenic in vitro and in vivo, but little information exists on the best time to harvest red clover fields to maximize content of the isoflavones and thus make an optimal product. Samples of cultivated red clover above-ground parts and flower heads were collected in parallel over one growing season in northeastern Illinois. Generally, autohydrolytic extracts of above-ground parts contained more isoflavones and had more estrogenic activity in Ishikawa endometrial cells as compared with extracts of flower heads. Daidzein and genistein contents peaked around June to July, while formononetin and biochanin A contents peaked in early September. Flower head and total above-ground parts extracts exhibited differential estrogenic activity in an Ishikawa (endometrial) cell-based alkaline phosphatase induction assay, whereas nondifferential activity was observed for most extracts tested in an MCF-7 (breast) cell proliferation assay when tested at the same final concentrations. Ishikawa assay results could be mapped onto the extracts' content of individual isoflavones, but MCF-7 results did not show such a pattern. These results suggest that significant metabolism of isoflavones may occur in MCF-7 cells but not in Ishikawa cells; therefore, caution is advised in the choice of bioassay used for the biological standardization of botanical dietary supplements.