Composition and antioxidant activity of the essential oils of Xylopia aethiopica (Dun) A. Rich. (Annonaceae) leaves, stem bark, root bark, and fresh and dried fruits, growing in Ghana

The chemical composition of the essential oils obtained from the leaves, the barks of the stem and the root, as well as from the fresh and dried fruits of Xylopia aethiopica, growing in Ghana, was investigated by gas chromatography/mass spectrometry analyses. Kovats indices, mass spectra, and standard compounds were used to identify a total of 93 individual compounds. The monoterpene hydrocarbons formed the main portion in all studied samples. beta-Pinene was predominant in all cases, while trans-m-mentha-1(7),8-diene was the main compound in the essential oils of the leaves and the barks of roots and stems. Their potential antioxidant activity was also investigated and found to be significant in scavenging superoxide anion radical.     

Formation of Damascenone under both commercial and model fermentation conditions

The fermentations, at a commercial winery, of six different grape musts encompassing the varieties Riesling, Chardonnay, Sauvignon blanc, Shiraz, Grenache, and Pinot noir were monitored for damascenone concentration. In every case, the concentration of damascenone increased during fermentation from low or undetectable levels to concentrations of several parts per billion. Further increases in damascenone concentration were observed during barrel aging of three of these wines. Two ketones, megastigma-4,6,7-triene-3,9-dione (4) and 3-hydroxymegastigma-4,6,7-trien-9-one (5), were synthesized and subjected to fermentation conditions using two yeasts, AWRI 796, and AWRI 1537. In the case of the former compound, 4, synthesis confirmed the original, tentative assignment of the structure and confirmed 4 as a natural product, isolated from honey. Both compounds, under the action of both yeasts, produced appreciable amounts of damascenone (1), with ketone 5 and AWRI 796 yeast yielding the highest concentration of 1.     

The formation of wine lactone from grape-derived secondary metabolites

Wine lactone (i.e., 3a,4,5,7a-tetrahydro-3,6-dimethylbenzofuran-2(3H)-one, 1a/1b) was formed hydrolytically at wine pH from both racemic (E)-2,6-dimethyl-6-hydroxyocta-2,7-dienoic acid (3) and the corresponding glucose ester 2a at 45 °C but at room temperature was only formed from the acid 3. The glucose ester does not appear to be a significant precursor for the formation of wine lactone in wine. The slow formation of wine lactone from the free acid 3 indicates that the acid is not likely to be an important precursor to wine lactone in young wines unless present in high concentration (? 1 mg/L), but could be a significant precursor to wine lactone in wine that is several years old. The wine lactone formed in hydrolysates of the (6R)-enantiomer of 3 was partially enriched in the (3S,3aS,7aR)-enantiomer 1a when the hydrolysis was conducted at pH 3.2 and 100 °C in a closed vessel or under simultaneous distillation-extraction (SDE) conditions, and the enantiomeric excess (ee) varied from 5 to 22%. Hydrolysis of (6R)-3 in sealed ampules at 45 °C and at pH 3.0, 3.2, or 3.4 gave near-racemic wine lactone, but when the hydrolyses were conducted at room temperature, the product was enriched in the (3S,3aS,7aR)-enantiomer 1a and the ee was greater at higher pH (up to 60% at pH 3.4).     

Development of high-throughput real-time PCR assays for the identification of insensitive acetylcholinesterase (ace-1) in Anopheles gambiae

Resistance to the organophosphate and carbamate insecticides through insensitivity of the target site enzyme, acetylcholinesterase has recently been reported in Anopheles gambiae populations in West Africa. To date, screening for the mutation (G119S of the ace-1 gene) conferring this insensitivity has employed a simple PCR-RFLP diagnostic. However, this has the disadvantage of requiring digestion of the amplified fragment and subsequent gel electrophoresis of the products. To overcome this, and thus increase throughput and reduce costs, we have developed two assays based on real-time PCR (TaqMan and melt-curve) that represent true ‘closed-tube’ approaches. The two new platforms were compared to PCR-RFLP to genotype over 280 samples. The two new methods compared favourably with PCR-RFLP with the TaqMan assay delivering the greatest specificity and sensitivity of the three approaches. This assay is also cheaper to run than PCR-RFLP and results are obtained in a single step.     

Biological and molecular characterization of field isolates of <Emphasis Type="Italic">Alternaria alternata</Emphasis> with single or double resistance to respiratory complex II and III inhibitors

Field isolates of Alternaria alternata collected from tomato processors were characterized for sensitivity to respiration inhibitors using in vitro mycelial growth assays. Pyraclostrobin (QoI), boscalid, fluopyram and isopyrazam (SDHIs) mean EC₅₀ values were 0.32, 1.43, 2.21, and 3.53 μg/ml respectively. Of the 42 isolates, 36 were sensitive to all respiration inhibiting fungicides tested whereas three isolates were less sensitive to boscalid, one to pyraclostrobin and two were simultaneously resistant to both inhibitors and isopyrazam. Correlation analysis between fungicide sensitivities revealed a positive cross-resistance between pyraclostrobin and tebuconazole, and between cyprodinil and mancozeb. There was no cross-resistance between QoIs, SHDIs or any other mode of action. Sequencing of the QoI and SDHI targets revealed the G143A cytochrome b resistance mutation in all pyraclostrobin-resistant isolates while analysis of the succinate dehydrogenase coding gene revealed point mutations in two of three of the gene subunits analyzed in boscalid-resistant isolates. Specifically, two isolates carried the H277Y and three the H133Q resistance mutations located in the sdhB and sdhD subunits of the respiration complex II, respectively. Isolates bearing the H277Y mutation also carried the G143A cytochrome b resistance mutation. Boscalid and pyraclostrobin-resistant isolates exhibited greater pathogenicity and sporulation compared to sensitive isolates, respectively. Isolates with cross-resistance exhibited greater pathogenicity and sporulation but slower mycelial growth compared to sensitive isolates. This is the first report of field isolates of A. alternata with single or double resistance to QoIs and SDHIs in Greece and should be considered in planning and implementing effective anti-resistance strategies.     

Rationalizing the formation of damascenone: synthesis and hydrolysis of damascenone precursors and their analogues, in both aglycone and glycoconjugate forms

Storage of megastigma-4,6,7-trien-3,9-diol (5), and megastigma-3,4-dien-7-yn-9-ol (6) in aqueous ethanol solution at pH 3.0 and 3.2 gave exclusively damascenone (1) and damascenone adducts at room temperature. The diol (5) had half-lives for the conversion of 32 and 48 h at pH 3.0 and pH 3.2, respectively. The acetylenic alcohol (6) had half-lives of 40 and 65 h at the same pH levels. In order to study the reactivity of the C-9 hydroxyl function in 5 and in the previously investigated allenic triol 2, two model compounds, megastigma-4,6,7-trien-9-ol (7) and megastigma-6,7-dien-9-ol (8) were synthesized. No 1,3-transposition of oxygen to form analogues of damascenone was observed when 7 and 8 were subjected to mild acidic conditions. Such transposition takes place only with highly conjugated acetylenic precursors such as 6 or tertiary allenic alcohols such as 2. The placement of glucose at C-3 of 5 and at C-9 of 6 gave the glycosides 9 and 10, respectively. The effect of such glucoconjugation was to increase the observed half-lives by a factor of only 1.6-1.7 for the allenic glucoside 9, and by 2.1-2.2 for the acetylenic glucoside 10. These studies indicate that the effect of glycosylation on damascenone formation is probably not important on the time scale of wine making and maturation.     

How potassium deficiency alters flower bud retention on cotton (Gossypium hirsutum L.)

Potassium (K) is fundamental for plant growth and development but despite the increased quantities of fertilizers applied, incidents of K deficiency are commonly observed. The objective of this study was to record the effects of K deficiency during cotton’s (Gossypium hirsutum L.) early reproductive stage on carbohydrate content and metabolism, total antioxidant capacity and oxidative damage of cotton flower buds as well as the physiology of the leaf, subtending to the flower buds. Growth chamber experiments were conducted using cotton cultivar DP0912 and treatments consisted of normal K and deficient K fertilization for the duration of the experiment. Potassium deficiency resulted in significant oxidative damage in the cotton flower buds, despite the substantial increase in their total antioxidant capacity. Sucrose metabolism of the flower buds was markedly affected resulting in significant reductions in all non-structural carbohydrate concentrations. Furthermore, K deficiency disturbed leaf physiology leading to increased membrane damage, decreases in chlorophyll and carotenoid content and ultimately leaf photosynthetic rates. Concomitant increases in specific leaf weight under K deficient conditions indicated reductions in photoassimilate translocation, which in conjunction with the disruptions observed in flower bud sucrose metabolism, due to the insufficient antioxidant response, resulted in significant decreases in flower bud retention.     

Business model for developing strategies of forest cooperatives. Evidence from an emerging business environment in Greece

ABSTRACT

Forest cooperatives are essentially a form of entrepreneurship. However, they are confronted by various problems and they cannot pay enough attention to value creation. The aim of this paper is twofold: (a) the identification of the structural factors supporting the function of Greek forest cooperatives and the exploration of the possibilities of applying business model innovation to them; (b) the investigation of how the development of an integrated business model can help cooperatives stay ahead in the innovation game, while securing sustainability. By applying business modeling procedures to the forest cooperatives of the Region of Thessaly (Greece) this paper presents, the implementation of innovative development strategy, within the current legislative framework. Results show that the business model approach gives them the ability to develop a shared vision for value creation and delivering through the establishment of a framework related to sustainable forest management based on creation of bonds for achieving a win-win strategy, satisfying the increasing needs for innovative forest-based products, which constitutes a challenge for the sustainable management of forests. We argue that this is the first time this approach has been made regarding forest cooperatives in Greece in relation to the emerging parameters of the general business environment.     

Drought‐induced osmotic adjustment and changes in carbohydrate distribution in leaves and flowers of cotton (Gossypium hirsutum L.)

Research has indicated osmotic adjustment as a mechanism by which leaves and roots of cotton plants overcome a drought period. However, the relevance of this mechanism in reproductive tissues of modern cultivars under drought has not been fully investigated. The objectives of this study were to measure osmoregulation and carbohydrate balance in reproductive tissues and their subtending leaves grown under water‐deficit conditions. Two cotton cultivars were grown under controlled environment and field conditions. Plants were exposed to water‐deficit stress at peak flowering, approximately 70 days after planting. Measurements included stomatal conductance, proline concentration, soluble carbohydrates and starch concentration, and water potential components. Stomatal conductance of drought‐stressed plants was significantly lower compared to control, while osmotic adjustment occurred in reproductive tissues and their subtending leaves by different primary mechanisms. Pistils accumulated higher sucrose levels, maintaining cell turgor in plants exposed to drought at similar levels to those in well‐watered plants. However, subtending leaves lowered osmotic potential and maintained cell turgor by accumulating more proline. Soluble carbohydrates and starch concentration in leaves were more affected by drought than those of floral tissues, with corresponding reduction in dry matter, suggesting that flowers are more buffered from water‐deficit conditions than the adjacent leaves.     

Effects of transporting and processing Sauvignon blanc grapes on 3-mercaptohexan-1-ol precursor concentrations

The effects of different processing treatments on thiol precursor concentrations have been investigated through studies involving transportation of machine-harvested Sauvignon blanc fruit and assessment of different applications of antioxidants, along with juice preparation and enzyme inhibition experiments. The influence these trials had on 3-S-cysteinylhexan-1-ol (Cys-3-MH) and 3-S-glutathionylhexan-1-ol (Glut-3-MH) concentrations in juices is discussed. Very interesting findings included the large increase in precursor concentrations after transportation, particularly for Cys-3-MH, and the limited formation of Glut-3-MH when grape proteins were precipitated during processing. The various results provided information about the ability to modulate precursor concentrations depending on the processing technique employed. Additionally, a conjugated aldehyde, which is the obvious missing link between the reaction of (E)-2-hexenal and glutathione in the formation of Glut-3-MH, has been tentatively identified for the first time. Deuterium-labeled 3-S-glutathionylhexanal (Glut-3-MHAl) was produced through the addition of labeled (E)-2-hexenal to grapes, followed by grape crushing, and detected in the juice by HPLC-MS/MS, along with the corresponding labeled Glut-3-MH.