Dynamics of anthocyanin and flavonol profiles in the ‘Crimson Seedless’ grape berry skin during development and ripening

‘Crimson Seedless’ grapes (Vitis vinifera L.) do not develop adequate berry colour in different parts of the world including Australia and USA leading to serious economic losses to the growers. In the present study, various anthocyanins and flavonols were identified in the skin of the ‘Crimson Seedless’ grape berries using LC/PDA/ESI-MS and their changes in the berry skin during development and ripening of ‘Crimson Seedless’ grape berries were investigated during 2005–2006 and 2006–2007. Eleven anthocyanins and two flavonols were identified in the berry skin using LC/PDA/ESI-MS. Of the anthocyanins identified, four anthocyanins including cyanidin 3-O-(6″-O-acetyl)-glucoside, peonidin 3-O-(6″-O-acetyl)-glucoside, malvidin 3-O-(6″-O-acetyl)-glucoside and malvidin 3-O-(6″-O-coumaroyl)-glucoside were not reported earlier. During both the years, the concentration of the 3-O-glucosides of delphinidin, petunidin, peonidin, and malvidin as well as the acetyl and coumaroyl esters of the 3-O-glucosides of cyanidin, peonidin, and malvidin in the berry skin increased during berry development and ripening. During 2006–2007, the concentration of cyanidin 3-O-glucoside in the berry skin increased during the early stages of berry ripening and subsequently declined till harvest while in 2005–2006, the concentration increased during the initial phase of berry ripening and remained relatively stable thereafter till harvest. The concentration of total anthocyanins in the berry skin was higher during 2006–2007 as compared to 2005–2006. During both years, the concentration of quercetin 3-O-glucoside in the berry skin increased during berry development and ripening while the concentration of quercetin 3-O-glucuronide in the berry skin decreased during the same period. To the best of our knowledge, this is the first report on the evolution of different anthocyanins and flavonols in the ‘Crimson Seedless’ berry skin during berry development and ripening.     

Carbon dioxide assimilation by virus-free sugarcane plants and by plants which were infected by Sugarcane Yellow Leaf Virus

Infection of sugarcane by Sugarcane Yellow Leaf Virus (SCYLV) remains mostly asymptomatic. The assimilation rates and the water relations parameters were measured to test whether the plants are already inflicted by the infection. The assimilation rate and the stomatal conductance were 10–30% higher in virus-free plants than in infected plants. The observed differences were significant in young potted plants, not in older field plants. Virus-free leaves had a higher bundle sheath leakiness and a lower ¹³C discrimination rate than infected leaves. The water relations parameters of SCYLV-infected asymptomatic plants showed resemblance to those of salinity- and drought-stressed plants.     

Indicator development in sustainability impact assessment: balancing theory and practice

In this article, the development and operationalisation of forestry-wood chain indicators within the frame of sustainability impact assessment are discussed. The analytical framework follows a distinction between indicator definition and selection in a first phase, and a second operational phase of indicator application in terms of interconnecting material flows, calculation of chain performance and utilisation within evaluation components. A clear boundary drawing effort in terms of the development of indicator definitions, related subclasses, and measurement units as well as the creation of conversion factors between indicator values and individual chain stages supports this. Economic, social and environmental indicators have to respond to data collection needs on individual process levels (that correspond to sub-divisions of the forestry-wood chain). For the usage of indicators within evaluation tools, a functional hierarchy has to be provided that supports clear preference elicitation as well as information on related externalities. In total, this paper aims at demonstrating an enhanced spectrum in the use of sustainability indicators, and the challenges that arise from a developing and applying multi-functional indicators in sustainability impact assessment.     

Acrylamide formation mechanism in heated foods

Recent findings of a potential human carcinogen, acrylamide, in foods have focused research on the possible mechanisms of formation. We present a mechanism for the formation of acrylamide from the reaction of the amino acid asparagine and a carbonyl-containing compound at typical cooking temperatures. The mechanism involves formation of a Schiff base followed by decarboxylation and elimination of either ammonia or a substituted imine under heat to yield acrylamide. Isotope substitution studies and mass spectrometric analysis of heated model systems confirm the presence of key reaction intermediates. Further confirmation of this mechanism is accomplished through selective removal of asparagine with asparaginase that results in a reduced level of acrylamide in a selected heated food.     

Enzyme immunoassay for tenuazonic acid in apple and tomato products

The Alternaria mycotoxin tenuazonic acid was derivatized with succinic anhydride and conjugated to keyhole limpet hemocyanin (KLH) and to horseradish peroxidase (HRP), respectively. The KLH conjugate was used to produce polyclonal antibodies in rabbits. A competitive direct enzyme immunoassay (EIA) for tenuazonic acid was established, which was moderately sensitive for tenuazonic acid [50% inhibition concentration (IC(50)): 320 ± 130 ng/mL] but strongly reacted with tenuazonic acid acetate (IC(50): 23.3 ± 7.5 ng/mL). Therefore, an optimized EIA protocol was established, which employed acetylation of standard and sample extract solutions. The mean standard curve detection limit (IC(30)) for tenuazonic acid acetate was 5.4 ± 2.0 ng/mL, enabling detection limits for tenuazonic acid in apple and tomato products of 25-50 ng/g (150 ng/g in tomato paste). Recoveries in a concentration range of 50-2000 ng/g were 60-130% in apple juice and tomato juice and 40-150% in other tomato products. Tenuazonic acid was detected in apple juice and tomato products from German retail shops at levels of 50-200 ng/g. In conclusion, this novel EIA for tenuazonic acid could be useful within a screening program for Alternaria mycotoxins in food.     

Elimination of Sugarcane yellow leaf virus from infected sugarcane plants by meristem tip culture visualized by tissue blot immunoassay

Sugarcane yellow leaf virus (SCYLV), a member of the Luteoviridae , is implicated in the sugarcane disease known as yellow leaf syndrome (YLS), which is characterized by yellowing of the leaf midrib followed by leaf necrosis and possible growth suppression. YLS is distributed worldwide and susceptible cultivars are commonly infected with SCYLV. However, not all cultivars infected with SCYLV show symptoms of YLS and some cultivars that show symptoms do so sporadically. Since it is difficult to obtain virus-free plants of susceptible cultivars, it has not been possible to study the factors involved in SCYLV infection nor the effects of infection on plant growth and yield. A tissue blot immunoassay was used to visualize in vivo presence of the virus so that virus-infected and virus-free plants could be distinguished. Meristem tip cultures were used to produce virus-free plantings of six SCYLV-susceptible sugarcane cultivars. Nearly all of the regenerated sugarcane lines remained virus-free over a period of up to 4 years, whether grown in isolated fields or in the glasshouse. Experimental re-infection of the virus-free plants by viruliferous aphids demonstrated that meristem tip culture did not affect susceptibility of sugarcane to SCYLV. Improved diagnosis and production of virus-free plants of SCYLV-susceptible cultivars will facilitate research to quantify the effect of the virus on yield and to analyse the processes involved in disease development.     

Solubilization of iron and calcium phosphates by soil fungi isolated from coffee plantations

Almost 900 fungal isolates were obtained from eight coffee plantations in Colombia and Mexico. Of these, 76 isolates showed activity to solubilize Ca₃(PO₄)₂ (PCa) and FePO₄·H₂O (PFe), which had been added to agar in a plate test. Generally, PCa was better solubilized than PFe. Colombian isolates were generally somewhat less effective than Mexican isolates. The two most effective isolates from each country with apparent highest PFe, solubilization potential were selected and cultivated in liquid medium containing PFe, which is more prevalent in tropical soils. The pH value, solubilized P in the medium and P uptake in fungal biomass were determined. After 24 days, Cylindrocarpon didymum and C. obtusisporum (both from Colombia) had solubilized 9.9 and 6.4 mg PO₄ ^3--P L^?1 and took up 8.6 and 11.6 mg P in biomass. Penicillium janthinellum and Paecilomyces marquandii (both from Mexico) solubilized 7.0 and 1.9 mg PO₄ ^3--P L^?1 and took up 11.3 and 17.3 mg P in biomass. The potential practical use of the four fungal isolates for different strategies in making more P available for coffee growth is discussed.     

Landbau und treibhauseffekt‐quellen und senken für CO2 bei unterschiedlicher landbewirtschaftung

Die Ergebnisse der Müncheberger Dauerversuche sind eine geeignete Datenbasis zur Bewertung der CO₂‐Senke im Landbau (produzierter Gesamtertrag und Akkumulation von organischer Bodensubstanz) sowie der CO₂‐Quelle (Verlust an organischer Bodensubstanz und Einsatz fossiler Energie). Durch diese Parameter sind wesentliche Größen für die Quantifizierung des C‐ bzw. CO₂‐Haushaltes gegeben. Sie sind Indikatoren für den Vergleich unterschiedlicher Bewirtschaftungsintensitäten und charakterisieren die Umweltverträglichkeit der Pflanzenproduktion.

Ein reduzierter Faktoreinsatz kann die CO₂‐Emission im Vorleistungsbereich der Landwirtschaft nur dann mindern, wenn dieser geringere Faktoreinsatz nicht mit deutlich geringerem Energiegewinn (CO₂‐Bindung im Ernteertrag) verbunden ist.

Ziel landwirtschaftlicher Bodennutzung ist es u.a., die Erhaltung standorttypischer C‐Gehalte im Boden zu gewährleisten. Langfristig kann durch kombinierte organischmineralische Düngung sowie konservierende Bodenbearbeitungsverfahren auf sandigen Böden eine Erhöhung des C‐Pools im Boden um ca. 10% erreicht werden.

Die CO₂‐Emissionen im Vorleistungsbereich der Landwirtschaft sollten auf sandigen Ackerstandorten 9 bis 10% der in der Biomasse gespeicherten CO₂‐Menge nicht übersteigen.