Use of Sulfur to Control pH in Composts Derived from Olive Processing By-products

Two composts were prepared from olive press cake (OPC) repeatedly turned and moistened with either olive mill wastewater (OPC+OMW) or water (OPC+W). When phytotoxicity was drastically reduced and the pH of the composts had reached 8.6 and 7.55 respectively, elemental sulfur was added at 0.9% of dry weight to the OPC+OMW compost and at five different doses (0.1 – 1.0% of dry wt) to the OPC+W compost. During the following six months, an exponential pH decline was observed in both compost materials. The pH reached a final value of 5.8 in the OPC+OMW compost whereas a pH decline related to the amount of added sulfur was observed in the OPC+W compost (final values from 6.8 to 4.3). Over 80% of the pH decline occurred during the first two months following the sulfur addition. Sulfur was applied following the stabilization of the material in the case of OPC+W. No phytotoxic effects of the final products were observed at sulfur application doses up to 0.5% of dry compost weight, but a significant germination index reduction was observed at the 1% dose, probably related to the increased conductivity of the compost leachate. Sulfur was applied before stabilization of the compost material, in the case of OPC+OMW, to also investigate the effects of sulfur addition on the composting process. A thermophilic phase similar to that observed after the last OMW application exceeding 50°C followed, and no effects on microbial activity profiles of the compost were observed. The results indicate that small amounts of elemental sulfur may efficiently control high pH values in the final compost products and could be safely applied at late composting stages or after composting. This may broaden the utilization of these composts in potting media and alkaline soils.     

Chronotypology and melatonin alterations in minimal hepatic encephalopathy

Background  

"Minimal (subclinical) hepatic encephalopathy" is a term that describes impairment of every day life activities in cirrhosis patients without clinical neurologic abnormalities. Melatonin diurnal pattern disruption and metabolic changes due to liver insufficiency can affect the human biologic clock. Our study was conducted to measure plasma melatonin levels in an attempt to correlate plasma melatonin abnormalities with liver insufficiency severity, and describe chronotypology in cirrhosis patients with minimal encephalopathy.     

Repeated application of diluted olive mill wastewater induces changes in the structure of the soil microbial community

Repeated application of diluted olive mill wastewater (OMW) is a common disposal method which allows the application of large amounts of OMW and improves the organic matter and nutrient status of Mediterranean soils. However, there is lack of information regarding the effects of this practice on the soil microbial community. A study was carried out to investigate these effects on the structure of the bacterial and fungal community of a loamy sand (LS) and a sandy loam (SL) soil, using denaturating gradient gel electrophoresis (DGGE) fingerprinting. OMW was daily applied as aqueous solutions of 0, 2 and 4%, in the presence or absence of nitrogen fertilization, for a three-month period. Multivariate analysis of the DGGE profiles showed that OMW applications resulted in marked changes in the fungal community in both soils, while nitrogen fertilization diminished these effects. Small effects were evident for the bacteria only in the LS soil and this was attributed to the higher availability of OMW-derived phenolics in this soil which resulted in a direct impact on bacteria. Nitrogen fertilization alleviated the effects of OMW on the bacterial community. We suggest that the impact of OMW on the structure of the soil microbial communities was mostly a result of its indirect effect on the soil nutritional status, which becomes enriched in organic substrates and poor in available nitrogen.     

Cytogenetic effects of grape extracts (Vitis vinifera) and polyphenols on mitomycin C-induced sister chromatid exchanges (SCEs) in human blood lymphocytes

In the present study, the effects of extracts and polyphenol-rich fractions as well as monomer polyphenols identified in them, from both red and white grapes, on mitomycin C (MMC) induced sister chromatid exchanges (SCEs) in human peripheral blood lymphocytes were investigated. The grape extracts and two of the three polyphenol-rich fractions promoted MMC-induced SCEs at concentrations from 75 to 300 microg/mL. However, none of the extracts or fractions alone induced SCEs. Thus, these results suggest caution especially with regard to the use of grape extracts as dietary supplements. On the other hand, the fact that these extracts were not genotoxic alone may indicate a selective activity against genetically damaged cells. This is the first study regarding the clastogenic effects of grape extracts in human cells. Moreover, from the tested polyphenols, caffeic acid, gallic acid, and rutin hydrate enhanced MMC-induced clastogenicity, whereas ferulic acid, protocatechuic acid, (+)-catechin, (-)-epicatechin, and trans-resveratrol had no effect at concentrations between 5 and 100 microM. The differences in the chemical structures of the tested polyphenols may account for their differential effects on MMC clastogenicity.     

Adaptation,Agronomic Potential,and Current Perspectives of Quinoa Under Mediterranean Conditions: Case Studies from the Lowlands of Central Greece

Quinoa was cultivated for 7000 years by indigenous people of the Andes, but in recent decades it is gaining international attention because of its tolerance to abiotic stresses, the wide genetic variability, and its high nutritional value. Greece was among the European countries and in the Mediterranean basin, the first European country, which since 1995 was involved in the “American and European Test of Quinoa” organized by the Food and Agriculture Organization and the Quinoa Project “CIP-DANIDA.” The experiments (1995–2004) were conducted in the lowlands of Central Greece (Larissa region). The first experiments focused on the adaptation of quinoa varieties to warm and dry climatic conditions and to the effect of plant density on seed yield (SY). Drought, low relative humidity, high temperatures (>32 °C), and long days (during anthesis) were considered unfavorable for seed production. Moreover, crusting and drying up of the soil surface had a negative effect on the proportion (60–70%) of emerged seedlings. The best sowing density is considered to be 25 plants m^?2. Considering the effect of sowing date on SY and quality, it was found that early sowing in March is more suitable (in areas where frost avoidance is ensured), whereas latest (May) sowing was unsuitable and resulted in poor germination. The evaluation of 25 quinoa varieties showed that only 8 (six European and two Latin American) varieties produced seeds, whereas the rest 17 produced only panicles and flowers. Dry matter quality of the produced stems was analyzed for protein and fiber content. Dry stems of the plants remained after seed harvest contained high percentage of fibers (45%). The eight most promising varieties were also evaluated for their yielding potential and their seed composition under contrasting soil properties. Compared to neutral soil conditions, SY in the saline–sodic soil was decreased up to 45%. Mineral and protein content in seeds was higher in the varieties originated from Latin America. SY for some varieties exceeded 1000–1500 kg ha^?1, and seeds were rich in protein (15–18.5%) and minerals content. On a breeding program started in 2002, 23 families have been created using mass selection procedures for the creation of new varieties from plants survived in the saline–sodic soils. These selections had to be evaluated in dense sowing in typical SY experiments, but experimentation was discontinued in the absence of financial support. Farmers’ knowledge gaps on cultivation techniques, the distances from the European markets, and the absence of incentives are probably considered the major obstacles to date for crop’s expansion in Greece. Research should focus on the evaluation of promising genetic material in different agroecological zones including higher altitudes.

Abbreviations: AETQ, American and European Test of Quinoa; FAO, Food and Agriculture Organization; SY, seed yield; a.s.l., above sea level; N, neutral soil; S-S. saline–sodic soil; B, branched plant types; UN-B, unbranched plant types.     

Selection and Screening of Endorhizosphere Bacteria from Solarized Soils as Biocontrol Agents Against Verticillium dahliae of Solanaceous Hosts

Verticillium dahliae antagonistic endorhizosphere bacteria were selected from root tips of tomato plants grown in solarized soils. Fifty-three out of the 435 selected bacterial isolates were found to be antagonistic against V. dahliae and several other soilborne pathogens in dual cultures. Significant biocontrol activity against V. dahliae in glasshouse trials was demonstrated in three of 18 evaluated antagonistic isolates, provisionally identified as Bacillus sp. Although fluorescent pseudomonads were also isolated from root tips of tomato plants, none of the tested isolates exercised any significant antagonistic activity against V. dahliae in dual cultures. So these isolates were not tested in glasshouse trials in this study. Finally, two of the most effective bacterial isolates, designated as K-165 and 5-127, were shown to be rhizosphere colonizers, very efficient in inhibiting mycelial growth of V. dahliae in dual cultures and successfully controlling Verticillium wilt of solanaceous hosts. In glasshouse experiments, root dipping or soil drenching of eggplants with bacterial suspension of 10⁷cfu ml^–1 resulted in reduced disease severity expressed as percentage of diseased leaves (40–70%) compared to the untreated controls under high V. dahliae inoculum level (40 microsclerotia g^–1 soil). In heavily Verticillium infested potato fields, experiments with potato seeds dusted with a bacterial talc formulation (10⁸cfu g^–1 formulation), showed a significant reduction in symptom development expressed as percentage of diseased potato plants and a 25% increase in yield over the untreated controls. As for their effectiveness in increasing plant height, both bacterial isolates K-165 and 5-127 produced indolebutyric, indolepyruvic and indole propionic acids. Both antagonists are considered as plant growth promoting rhizobacteria bacteria since significantly increased the height of treated plants compared with the untreated controls. Chitinolytic activity test showed that both isolates were able to produce chitinase. Testing rhizospheric and endophytic activity of the antagonists it was shown that although the bacteria are rhizosphere inhabitants they also preferentially colonize the endorhizosphere of tomatoes and eggplants. Fatty acid analysis showed that isolate K-165 could belong to Paenibacillus alvei while 5-127 to Bacillus amiloliquefaciens.     

The effect of a natural feed additive (Macleaya cordata), containing sanguinarine,on the performance and health status of weaning pigs

The aim of this study was to investigate the efficacy of Sangrovit^®, a plant‐derived feed additive, given throughout the nursery stage via feed at 15 ppm and 50 ppm, on the health status and performance of weaners against negative controls. In a 900‐sow farrow‐to‐finish farm, a total of 864 piglets were divided into three groups: (i) negative controls (NC); (ii) Sang 15: same feed as NCs, plus 15 g Sangrovit^® /t of feed; (iii) Sang 50: same feed as NCs plus 50 g Sangrovit^® /t of feed. The results indicated that administration of 50 ppm^‐Sangrovit^® had the most beneficial effects on growth performance in weaning pigs. Specifically there was increase of body weight and average daily gain, as well as reduction of feed conversion ratio. Blood analysis from the Sang groups and especially the Sang 50 group revealed low values of haptoglobin and serum amyloid A.     

Physiological responses associated to substrate water availability of Rosa ‘Eurored’ plants grown in soilless greenhouse conditions

The aim of the present study was to provide a better insight into the adaptive processes to water deficit of Rosa hybrid plants grown in soilless cultivation. Rose plants were grown in a greenhouse under two water regimes, corresponding to 100% and 67% of the irrigation needs. Watering was stopped for 0, 72, and 96 h (dry-down period) and photosynthetic parameters, water relations, chlorophyll fluorescence, carbohydrate and ion content were determined.