Monitoring the benzene contents in soft drinks using headspace gas chromatography-mass spectrometry: a survey of the situation on the belgian market

Whenever benzoic acid is combined with ascorbic acid in acidic beverages such as soft drinks, benzene can be formed. To determine the current situation on the Belgian market, a headspace gas chromatographic-mass spectrometric method was developed, which needs little to no sample preparation. This method was then used to analyze 134 soft drinks sampled on the Belgian market by the Federal Agency for the Safety of the Food Chain. Thirty-three percent of the samples contained no detectable benzene, whereas the majority of the samples (47%) contained trace amounts below the limit of quantification of the method (0.3 microg L (-1)). Ten samples were above the European limit for benzene in drinking water of 1 microg L (-1), and one sample had a concentration of 10.98 microg L (-1), thereby exceeding the action limit for benzene in soft drinks of 10 microg L (-1) discussed at the Standing Committee on the Food Chain and Animal Health of the European Commission. Statistical analyses revealed that besides benzoic acid, ascorbic acid, and acidity regulators, the packing may also play an important role in benzene formation.     

Mapping quantitative trait loci conferring blast resistance in upland indica rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.)

A genetic analysis of blast resistance in upland rice variety is very crucial. In this study, we performed a linkage mapping of quantitative trait loci (QTLs) for blast resistance using an advanced backcross population from a cross between Way Rarem (susceptible indica variety) and Oryzica Llanos 5 (durable resistant indica variety). A transgressive segregation was observed in the advanced backcross population of Way Rarem//Oryzica Llanos 5. A total of 16 QTLs have been identified along chromosomes 1, 3, 5, 6, 7, 8, 9, and 11 against eight blast pathogen isolates. Each QTL accounted from 11.31 to 45.11% of the variation in blast resistance. Most QTLs showed race specificity, demonstrating the small effect of such QTLs. Unexpectedly, several superior blast resistance alleles were contributed by Way Rarem, the susceptible-recurrent parent. Among eight candidate defense response genes detected in several loci, a single gene (oxalate oxidase) present on chromosome 3 was found to be associated with blast resistance in upland indica rice. Ultimately, these advanced backcross lines with resistance to blast tagged by markers might be useful for pyramiding blast resistance alleles in upland rice.     

Mass spectrometric fingerprints of seed protein for defining Lupinus spp. relationships

The Lupinus genus consists of 200–600 species with diversified morphological and biochemical characteristics that provide scope for increasing the value of protein attributes in commercial lupin species through genetic improvement. This study characterised protein polymorphism among 33 selected lupin genotypes representing 19 species from Old World and New World using Matrix-Assisted Laser Desorption Ionization Time-Of-Flight (MALDI-TOF) mass spectrometry with the aim of developing a high throughput screen for assessing variation among samples within a genetic resource. MALDI-TOF mass spectrometry analysis recognized 630 polymorphic protein mass peaks. A total of 19 protein mass peaks were identified as species specific and 23 were recognized to be generally common (observed in more than 10 species). A set of 111 rare protein mass peaks common to 2–3 species were identified to uniquely distinguish the respective species in combination with the species specific mass peaks. Overall, the seed protein profiles showed extensive diversity among the species analysed. Phylogenic analysis based on the protein mass peaks clustered the Old World smooth and rough-seeded and New World lupin species separately, in broad agreement with clustering based on morphological characters, life history, cytogenetics, DNA polymorphism and electrophoreses of seed proteins. Two New World lupin species, L. mutabilis Lindl. and L. succulentus Douglas ex K. Koch were grouped into the smooth-seeded Old World group.     

Influence of paddy rice terraces on soil erosion of a small watershed in a hilly area of Northern Vietnam

Soil erosion is the main cause of soil degradation in northern Vietnam. In this study, soil erosion was measured in 2 m² field plots, a 19.1-ha sub-watershed, and a 248.9-ha main watershed in Tam Quan commune, Tam Duong district, northern Vietnam during 2 years, i.e., 2004–2005. The main watershed includes lowland paddy fields, and is representative for watersheds in the northern Vietnamese landscape. Soil erosion was measured for eight events, at all the three scales to increase our understanding of erosional processes and to assess the effects of paddy fields within the main watershed. The results show that total discharge and sediment yield in both sub-watershed and main watershed were much lower than those in the field plots. Total discharge per unit area in the main watershed was higher than in the sub-watershed, because during the growing season, the paddies are filled with water and any rainfall on them therefore becomes runoff. Sediment yield in the main watershed fluctuated, depending on the soil erosion contribution from many sub-watersheds. Annual rainfalls in 2004 and 2005 were 1,172 and 1,560 mm, respectively, resulting in corresponding total discharges of 54 and 332 mm and total soil losses of 163 and 1,722 kg ha^?1 year^?1. High runoff volumes occurred in July, August, and September, but April, June, the last 10 days of September and October, were the susceptible periods for soil erosion in the study area because of low plant cover and many agricultural activities during these periods.     

Production of Ochratoxin A by Aspergillus Ochraceus

The effects of growth conditions, trace metals, carbon and nitrogen source on ochratoxin A (OTA) production by Aspergillus ochraceus NRRL 3174 were investigated in submerged liquid culture medium. No correlation between biomass production and OTA synthesis was observed. OTA production depended on the initial pH and was influenced by changing the pH of the culture medium. This effect was not due to differences in the availability of metal ions. At pH 6.5, 0.2 mg l^?1 Zn increased biomass and OTA production by 50%. Fe at 0.12 mg l^?1 resulted in a 40% decrease in the amount of OTA/biomass although the quantity of biomass was not affected. Amounts of OTA produced per biomass increased with decreasing glucose concentrations. Lactose triggered the highest amounts of OTA/biomass despite low yields of biomass. NO₃ ^? stimulated the amount of OTA/biomass by 25% and NH₄ ⁺ reduced the amount of OTA/biomass by 25% compared with NH₄NO₃ as nitrogen source.     

Production and phenology of the fruit shrub Eugenia stipitata in agroforestry systems in Costa Rica

Arazá (Eugenia stipitata), a fruit shrub originating from Western Amazonia, was evaluated growing in association with timber shade trees (Acacia mangium or Cordia alliodora) or with plantain (Musa sp.) as a potential commercial species for the tropical moist lowlands of Talamanca, Costa Rica. Height and crown width of the four-year-old shrubs varied between 2.7–2.8 m and 2.9–3.1 m, respectively. Flowering was positively correlated with initial fruit formation 1 month later and initial fruit formation with fully developed fruits a subsequent month after that. Three to four-year-old plants produced 20.0, 20.0, and 24.5 t ha⁻¹ yr⁻¹ (fresh fruits) in associations with A. mangium, C. alliodora and plantain, respectively, with higher production in rainy months. Fruit production in later years under C. alliodora (six to eight-year-old shrubs) was 26.5 t ha⁻¹ yr⁻¹. Where markets exist for E. stipitata fruit, the association can be recommended for tropical humid lowlands of Central America.     

Transpiration of Arabica Coffee and Associated Shade Tree Species in Sub-optimal, Low-altitude Conditions of Costa Rica

Sap flows of coffee (Coffea arabica L. cv ‘Costa Rica 95’) and associated timber trees (Eucalyptus deglupta or Terminalia ivorensis) or leguminous tree (Erythrina poeppigiana) were measured simultaneously during 12 months in 4-year-old coffee agroforestry systems in sub-optimal ecological conditions of Costa Rica. In the wet period, coffee and shade tree transpiration followed the daily patterns of photosynthetic photon flux density (PPFD) and reference evapotranspiration (ETo) while their transpiration was restricted at higher air VPD values (>1.5 kPa) registered during the dry period. Coffee transpired more per unit leaf area in full sun than under shade, an indication of higher environmental coffee stress in non shaded conditions. Nonetheless, coffee daily water consumption per hectare was generally higher under shade than in full sun due higher vegetative growth of shade-grown coffee plants. Minimum and maximum daily transpiration were 0.74 and 4.08 mm for coffee, 0.35 and 1.06 mm for E. deglupta, 0.70 and 2.10 mm for T. ivorensis and 0.13 and 0.79 mm for E. poeppigiana. Estimation of the annual combined water transpiration by coffee and shade trees was 20–250% higher than that of coffee grown in full sun. Nevertheless, there was no evidence that water use by associated trees decreased soil water availability for coffee and hence limited coffee transpiration in the dry season due to its relatively short length (3 months) and the high annual rainfall (over 3100 mm). In the sub-optimal, low altitude conditions of this experiment, E. deglupta was the optimum shade species as it maintained a more constant shade level throughout the year and ensured a better protection to coffee underneath than T. ivorensis and E. poeppigiana which underwent a complete defoliation during the adverse meteorological conditions of the dry period.     

Using ecological forest site mapping for long-term habitat suitability assessments in wildlife conservation—Demonstrated for capercaillie (Tetrao urogallus)

Although key factors for vegetation composition and structure, site and soil condition have received little attention as predictors of habitat suitability in wildlife ecology to date. Using the example of capercaillie (Tetrao urogallus), an indicator species for open, well-structured forest habitats, we evaluated the potential use of ecological forest site mapping for the identification of areas where the preferred vegetation structures are supported by the prevailing soil conditions. These are sites that we, therefore, expected to be of long-term relevance to the species.     

Cloning and characterization of a novel low molecular weight glutenin subunit gene at the Glu-A3 locus from wild emmer wheat (Triticum turgidum L. var. dicoccoides)

Amplification of the coding region, and upstream and downstream sequences of a low-molecular-weight glutenin subunits (LMW-GS) gene from wild emmer wheat (Triticum turgidum L. var. dicoccoides, 2n = 4x = 28, AABB) accession TD22 was carried out using designed allele-specific PCR (AS-PCR) primers. The complete 1,176 bp sequence of a novel LMW-i type subunit gene at the Glu-A3 locus, named LMW-TD22, is described. Analysis of the nucleotide and deduced amino acid sequences showed that this gene possessed striking characteristics although its molecular structure was generally similar to those of previously reported i-type LMW-GS genes that were isolated from common wheat and related species. The deduced amino acid sequence of LMW-TD22 gene contained 390 amino acid residues with the predicted molecular weight being 43,009.3 Da, which appeared to be the longest gene among the cloned LMW-i type genes from bread wheat and related species. The distinct feature of LMW-TD22 was two long polyglutamine stretches of 12 and 17 glutamines occurring in the repetitive and C-terminal domains as well as a cysteine residue present in the seventh amino acid residue of the signal peptide. These polyglutamine repeats are believed to improve the structure of gluten polymer and increase the strength of dough formed from the polymer. In addition, the putative 44 k subunit encoded by LMW-TD22 was verified by N-terminal microsequencing, gel electrophoresis and matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) analysis. Certain types of post-translational modifications, such as phosphorylation and glycosylation, may be associated with this LMW-i type subunit. A. Wang and Y. Xiao made equal contribution to the research as the first author.     

Fine-root dynamics of coffee in association with two shade trees in Costa Rica

Fine-root dynamics (diameter < 2.0 mm) were studied on-farm in associations of Coffea arabica with Eucalyptus deglupta or Terminalia ivorensis and in a pseudo-chronosequence of C. arabica-E. deglupta associations (two, three, four and five years old). Coffee plants were submitted to two fertilisation types. Cores were taken in the 0–40 cm soil profile two years after out-planting and subsequently in the following year in depth layers 0–10 and 10–20 cm, during and at the end of the rainy season, and during the dry season. Fine root density of coffee and timber shade trees was greater in the coffee fertilisation strip as compared to unfertilised areas close to the plants or in the inter-rows. Coffee fine roots were more evenly distributed in the topsoil (0–20 cm) whereas tree fine roots were mostly found in the first 10 cm. Although the two tree species had approximately the same fine root length density, lower coffee / tree fine root length density ratios in T. ivorensis suggest that this shade tree is potentially a stronger competitor with coffee than E. deglupta. Coffee and tree fine root length density for 0–10 cm measured during the rainy season increased progressively from two to five-year-aged associations and coffee fine root length density increased relatively more than E. deglupta fine root length density in the four and five-year-aged plantations suggesting that contrary to expectations, coffee fine roots were displacing tree fine roots.