Discrimination of wild and cultured european sea bass (Dicentrarchus labrax) using chemical and isotopic analyses

Recent legislation in the European Union (EC/2065/2001) requires that seafood must provide the consumer with information that describes geographical origin and production method. The present studies aimed to establish methods, based on chemical and stable isotopic analysis, that could reliably differentiate between wild and farmed European sea bass (Dicentrarchus labrax). The study measured fatty acid and isotopic compositions (delta13C and delta18O) of total flesh oil, delta15N of the glycerol/choline fraction, and compound-specific analysis of fatty acids (delta13C) by isotope ratio mass spectrometry. The sample set comprised 10 wild and 10 farmed sea bass from England (wild) and Scotland or Greece (farmed). Discrimination was achieved using fatty acid composition with 18:0, 18:2n-6, 20:4n-6, and 22:6n-3 providing the highest contributions for discrimination. Principal component analysis of the data set provided good discrimination between farmed and wild sea bass where factor 1 and factor 2 accounted for 60% of the variation in the data.     

Use of near-infrared spectroscopy for fast fraud detection in seafood: application to the authentication of wild European sea bass (Dicentrarchus labrax)

The possibility of using near-infrared spectroscopy (NIRS) for the authentication of wild European sea bass ( Dicentrarchus labrax ) was investigated in this study. Three different chemometric techniques to process the NIR spectra were developed, and their ability to discriminate between wild and farmed sea bass samples was evaluated. One approach used spectral information to directly build the discrimination model in a latent variable space; the second approach first used wavelets to transform the spectral information and subsequently derived the discrimination model using the transformed spectra; in the third approach a cascaded arrangement was proposed whereby very limited chemical information was first estimated from spectra using a regression model, and this estimated information was then used to build the discrimination model in a latent variable space. All techniques showed that NIRS can be used to reliably discriminate between wild and farmed sea bass, achieving the same classification performance as classification methods that use chemical properties and morphometric traits. However, compared to methods based on chemical analysis, NIRS-based classification methods do not require reagents and are simpler, faster, more economical, and environmentally safer. All proposed techniques indicated that the most predictive spectral regions were those related to the absorbance of groups CH, CH(2), CH(3), and H(2)O, which are related to fat, fatty acids, and water content.     

Structural changes of hake (Merluccius merluccius L.) fillets: effects of freezing and frozen storage.

Structural changes in hake (Merluccius merluccius L.) fillets as affected by freezing method and frozen storage temperature have been studied through Raman spectroscopy and related to changes in texture and functionality. Changes in protein secondary structure were observed due to storage temperature, accompanied by changes in apparent viscosity and shear resistance. Samples at -10 degrees C showed greater structural alteration than at -30 degrees C in terms of increase of beta-sheets at the expense of alpha-helices. An increase of unordered protein structure was found only in samples stored at -10 degrees C. Exposure of buried tryptophan residues was observed at both storage temperatures. The decrease of the deltaCH(2) band upon storage suggested an increase of hydrophobic interactions of aliphatic residues. Except for liquid air frozen fillets, all samples showed a decrease of the nuO-H/nuC-H band ratio compared to the fresh ones, this decrease being higher the harsher the conditions.     

Rheology of sea buckthorn (Hippophae rhamnoides L.) juice.

Juice extracted from sea buckthorn fruits was subjected to dynamic rheological measurements in a controlled stress rheometer. Sea buckthorn juice exhibited wide variations in flow behavior from pseudoplastic to dilitant with increasing temperature. The power law model suitably (r >/= 0.975, P相似文献   

Biological Parameters Towards Polycyclic Aromatic Hydrocarbons Pollution: A Study with Dicentrarchus labrax L. Exposed to the Model Compound Benzo(a)pyrene

The objective of the present study was to investigate the short-term effects of benzo(a)pyrene (BaP) on juvenile sea bass (Dicentrarchus labrax L.) using a multiparameter approach. At the end of the 96?h of exposure to a range of BaP concentrations (2?C256???g?l^?1) in laboratorial conditions, a suite of biomarkers involved in biotransformation pathways, oxidative stress and damage, neurotransmission and energetic metabolism were analysed. Levels of BaP metabolites in bile and BaP-type compounds in tissues were also included as biomarkers of exposure, and the post-exposure swimming velocity was used as a toxicity endpoint at a higher level of biological organisation. In addition, a time-series experiment on the levels of bile BaP metabolites was also performed. Increased levels of BaP metabolites in bile and BaP-type compounds in liver and brain of exposed fish were found, indicating BaP uptake, metabolisation and distribution by different tissues. BaP induced oxidative stress and damage, but no significant effects on the post-exposure swimming velocity, neurotransmission and energetic pathways were found. An increase in the levels of BaP metabolites in bile over time was also observed, reaching a threshold similar at all the concentrations tested. Overall, this integrative multiparameter study reflecting different biological responses of D. labrax was suitable to assess the effects caused by the short-term exposure to BaP and may be useful in the marine environmental risk assessment of polycyclic aromatic hydrocarbons pollution. The observed toxic effects also highlight the relevance of short-term exposure to relatively high concentrations of chemicals, as can occur in the case of punctual heavy chemical releases, such as oil spills in the marine environment.     

Genetic inheritance analysis of four enzymes in date-palm (Phoenix dactylifera L.)

The genetic inheritance of four date-palm enzymes hasbeen carried out in 29 Tunisian cultivars. Our data provide evidenceof five polymorphic genes involving 12 alleles. It has been assumedthat either Pgm or Shdh are specified by three different alleles,while Got-1, Got-2 and Pgi-2 loci are biallelicgenes. On the other hand, analysis throughout progenies of twocontrolled crosses support significantly these hypothesis. In thewhole, results are in agreement with reports that describeddate-palm isozymes. Nevertheless, we assume that other alleleare involved in Pgm gene. Also, isozymes controlled by Got-2locus are of a dimeric structure. Opportunely, it can be establishedthat the resultant isoenzymes would constitute polymorphic markerssuitable to analyze the genetic diversity in date-palm.     

Mechanical weeding effects on soil structure under field carrots (Daucus carota L.) and beans (Vicia faba L.)

The successful production of organic vegetables relies heavily on mechanical weeding, flame weeding and stale seedbeds. These operations involve repeated passes by tractors. Mechanical weeding also involves regular tillage. This combination of repeated tillage and compaction changes soil structure. We studied these structural changes in two fields of organic carrots and one field of beans in eastern Scotland. Structure was described by measuring soil strength with a vane shear tester and a cone penetrometer, by measuring bulk density and by visual assessment. Under beans, vane shear strength below the growing root zone was highly variable and in some areas was high enough to restrict root growth (>50 kPa). The carrots were grown in beds containing crop rows separated by bare soil. The bare soil was regularly weeded mechanically. The structure of this weeded soil in the top 10 cm layer of a loam eventually became disrupted and compacted enough to deter root growth (vane shear strength of 70 kPa). In addition the topsoil and subsoil in the wheel-tracks between the beds became very compact with little distinguishable structure. This compaction extended to the subsoil and persisted into the next cropping season (cone resistance >3 MPa at 35–50 cm depth). Reduced tillage by discing without ploughing was used to incorporate the straw used to protect the carrots overwinter and prepare the soil for the next crop. The resulting topsoil quality was poor leading to anaerobic growing conditions which restricted growth of the following crop and led to losses of the greenhouse gas nitrous oxide. The greatest threat to soil quality posed by mechanical weeding was subsoil compaction by tractor wheeling.     

Residual nitrogen effects on a succeeding oat (Avena sativa L.) Crop of clover species and ryegrass (Lolium perenne L.) undersown in winter wheat (Triticum aestivum L.)

The aim of the present investigation was to study the effect of white clover (var. Milka and Donna), red clover (var. Fanny) and ryegrass (var. Tove) undersown in winter wheat on a succeeding oat crop. Under the climatic conditions prevailing in Sweden, growing a catch crop after winter cereals is of particular interest because the latter are usually followed by a spring sown crop, leaving the ground bare during autumn and winter. Field trials were carried out during three growing seasons in an integrated farming system and for one year in an organic farming system. Competition from the dense wheat crop in the integrated farming system had a negative effect on the undersown species, and at harvest of the wheat they showed quite poor growth in all three years, with nitrogen contents under 5 kg ha^?1. No significant yield increase was measured without added nitrogen when the averages for all three years were calculated. On average, the grain yields were improved by 750 kg ha^?1 (14% moisture content) for the treatments with undersown clover for all three years when 90 kg N ha^?1 were added. The experiment within the organic system showed a different pattern with a better development of the undersown clover species, with nitrogen contents approximately 25 kg ha^?1 and an improvement in oat grain yield, from around 2?000 kg ha^?1 for the control to almost 3?500 kg ha^?1 with clover undersown the previous year.     

Changes in antioxidant effects and their relationship to phytonutrients in fruits of sea buckthorn (Hippophae rhamnoides L.) during maturation

Different fractions of sea buckthorn fruits were investigated for antioxidant activity and its relationship to different phytonutrients. Capacity to scavenge radicals of the crude extract, like the phenolic and ascorbate extracts, decreased significantly with increased maturation. The changes were strongly correlated with the content of total phenolics and ascorbic acid. Antioxidant capacity of the lipophilic extract increased significantly and corresponded to the increase in total carotenoids. The phenolic fractions made a major contribution to the total antioxidant capacity due to the high content of total phenolics. The lipophilic fractions were most effective if the comparison was based on the ratio between antioxidant capacity and content of antioxidants. The crude extract of fruits showed the highest inhibitory effect in both 2,2-azobis(2,4-dimethylvaleronitrile) (AMVN) and ascorbate-iron induced lipid peroxidations. The aqueous and ascorbate-free extracts showed higher inhibition in the AMVN assay, but lower inhibition in ascorbate-iron induced peroxidation, than the lipophilic extract.     

Impact of UV-C irradiation on the cell wall-degrading enzymes during ripening of tomato (Lycopersicon esculentum L.) fruit

The effect of a hormic dose of UV-C (254 nm) on changes in fruit firmness and cell wall-degrading enzyme (CWDE) activity was determined using tomato fruit. Throughout the storage period, a decrease in firmness was jointly observed with an increase of the CWDE (polygalacturonase, pectin methyl esterase, cellulase, xylanase, beta-D-galactosidase, and protease) activity for all treatments, suggesting the involvement of these enzymes in the ripening process. However, the enhancement in the activity of the CWDE was significantly less in fruit subjected to the hormic dose of UV-C. This reduction may explain why irradiated fruit were firmer than control and consequently may explain how UV-C could delay the ripening and senescence process. We suggest that the CWDE are one of the targets of the UV-C, and by this action, irradiation contributed to a delay of the cell wall degradation and consequently retarded softening of the tomato fruit tissues.     

Tocopherols and tocotrienols in sea buckthorn (Hippophae rhamnoides L.) berries during ripening

Sea buckthorn berries ( Hippophae rhamnoides L.) are used in foods, cosmetics, and pharmaceutical products. They are of particular interest for their high content of healthy phytochemicals, including vitamin E-related compounds (tocopherols and tocotrienols). This study investigated the content of tocopherols and tocotrienols during ripening in berries from four cultivars of sea buckthorn over a three-year period. The results showed large variations in tocopherols and tocotrienols depending on harvest date, cultivar, and year. Levels of alpha-tocopherol were higher early in the ripening period, while at later dates, delta-tocopherol levels increased. Great differences in amounts and composition of tocopherols and tocotrienols were observed between cultivars. Tocopherol levels were positively correlated with daily temperature, but this trend varied between years. Variations in tocopherols and tocotrienol levels in sea buckthorn berries due to cultivar, year, and ripening stage should therefore be considered in the production of nutritional products.     

Evaluation of the Sub-lethal Toxicity of Bleached Kraft Pulp Mill Effluent to Carassius auratus and Dicentrarchus labrax

The effluents from bleached Kraft pulp mill (BKME) and paper industry are toxic to different aquatic organisms being an important source of contamination to aquatic environments due to the presence of several chemicals produced during the production of Kraft pulp. The main objective of the present study was to evaluate the exposure effects of a secondary-treated BKME in two different species of fish: Carassius auratus and Dicentrarchus labrax. Both species were exposed to different concentrations of secondary-treated effluent (1%, 10%, 25%, 50%, 100%) in semi-static tests under controlled laboratory conditions. At the end of the experimental period (21 days), samples of livers were collected for CYP1A determination and histopathological evaluation. The results show significant changes (p?<?0.05) of CYP1A induction in carp exposed to 50% and in sea bass exposed to 25% of the effluent. Histopathological alterations were also observed according to the different concentrations of the tested effluent suggesting that tested BKME cause damage to exposed organisms.     

Phytosterols in sea buckthorn (Hippopha? rhamnoides L.) berries: identification and effects of different origins and harvesting times.

Sterols in seeds, pulp/peel fractions, and whole berries of sea buckthorn (Hippopha? rhamnoides L.) samples belonging to two major subspecies (sinensis and rhamnoides) from Finland and China were analyzed as TMS derivatives by gas chromatography-mass spectrometry after saponification of the oils. The total sterol contents in the seeds, the fresh pulp/peel, and the whole berries were 1200-1800, 240-400, and 340-520 mg/kg, respectively. The corresponding values in the extracted oils were 12-23, 10-29, and 13-33 g/kg. Sitosterol constituted 57-76 and 61-83%, respectively, of the seed and pulp/peel sterols. The sterol content and composition showed little variation between subspecies and collection sites. Different harvesting dates showed significant effects on the levels of some sterols both in the seeds and in the pulp/peel. The sterol profiles obtained are useful for characterizing sea buckthorn and detecting adulterations of the valuable oils. The information provided by the present investigation is also important for further chemical investigation of sea buckthorn sterols and industrial utilization of the berries as a raw material of functional foods.     

Ozone and drought stress — Interactive effects on the growth and physiology of Norway spruce (Picea abies (L.) Karst.)

Young trees of Norway spruce (Picea abies (L.) Karst.) were grown in 120 litre pots under two different ozone levels in open-top chambers for three seasons, 1992–1994. The ozone treatments were charcoal filtered air (CF, average 24 h seasonal mean 6.5 ppb) and non-filtered air with extra ozone aiming to track 1.5 times ambient (NF+, average seasonal mean 34 ppb). In addition, half of the spruce trees in Aug – Sep each season recieved a drought period of between five and seven weeks. The remaining half were kept well-watered. The soil water content, the needle water potentials, and the gas exchange as well as the chamber micro climate were measured before, during and after the drought period. Furthermore, the growth of the trees was measured as biomass increase. During the 1993 drought period, where the trees experienced a moderate drought stress, the trees grown in NF+ consumed soil water faster and showed a higher needle conductance compared to CF. However, no negative effects were found on needle water potential or growth. During the more severe 1994 drought stress period we did not find any differences between the two ozone treatments in soil water consumption, needle conductance or needle water potential. There was a significant negative effect of the high ozone treatment on tree biomass of the well-watered trees. Total plant biomass was reduced 18 % and stem biomass was reduced as much as 28 %. The negative effect of ozone on tree biomass was much smaller for the droughted trees.     

CO2-Enrichment effects on eelgrass (Zostera marina L.) and bull kelp (Nereocystis luetkeana (mert.) P & R.)

I investigated the effect of CO₂-enrichment on productivity of two aquatic plant species [Zostera marina L., Nereocystis luetkeana (Mert.) P. & R.] that form significant components of coastal ecosystems in the Pacific Northwest. Short-term (i.e., 2-hr) experiments showed that doubling CO₂ resulted in up to a 2.5-fold increase in Zostera net apparent productivity (NAP). Nereocystis NAP was increased 2.2 – 2.8 fold. In experiments involving seven enrichment treatments, NAP increased with increasing CO₂ between ambient (1.0×) and 2.5× CO₂ in both Zostera and Nereocystis. Nereocystis and Zostera NAP was lowest at highest (i.e., 5×) CO₂ concentrations. In growth experiments, mean growth rate of Zostera increased with increasing CO₂ during one of the two trials. I conclude that increasing CO₂ in the surface waters of the coastal ocean would predictably result in increased NAP of these two species. These results supplement limited published data showing that shallow estuarine and marine systems are vulnerable to increased carbon dioxide.     

向日葵对土壤中铜的积累作用研究

温室内不同Cu浓度添加土壤的向日葵盆栽试验表明,向日葵植株的部分生物学性状如地上部干物质量、地下部干物质量、最大单叶面积随土壤中Cu浓度的增加而降低,土壤中添加20mg/kgCu对向日葵根部生长抑制作用最大,而植物高度在添加100mg/kgCu浓度时最高。且不同Cu浓度处理下向日葵对Cu的积累能力不同,但植物各部分Cu含量均随土壤中添加Cu浓度的增加而增加,但在100mg/kgCu浓度处理下,向日葵对Cu的积累主要集中在根部,地上部分Cu含量很低,在200mg/kgCu浓度处理下,向日葵叶中Cu含量超过根部,达857±297mg/kg干重,Cu积累的叶根比达1.27,说明当土壤Cu浓度较高时,Cu在向日葵地上部有较高的Cu积累,集中收获植株地上部分,可移出土壤中的过多有效铜,但生长受到抑制。使用向日葵修复高浓度Cu污染土壤时,还需考虑采用其他手段接种根际微生物、转基因、设施农业环境工程技术等来增加其生物产量。     

Regulatory effects of sulfur on oilseed rape (Brassica napus L.) response to selenite

Selenite is a form of selenium (Se) commonly found in Se-excessive soils. To regulate the Se content in plants in high-Se areas, a potted soil experiment was performed on oilseed rape (Brassica napus L.) to evaluate the effects of varied amounts of sulfur (S) on the biomass, accumulation and distribution of Se in B. napus under the conditions of different amounts of Se in the soil. The results showed that the seedlings of B. napus were more sensitive to Se than the mature plants were. The addition of S significantly alleviated the growth inhibition in seedlings and facilitated the growth of mature plants under higher Se (15 mg kg^?1) conditions. S treatment significantly decreased soil pH within the range of 0.22–0.60. An appropriate moderate amount (150 mg kg^?1) of S exerted the strongest inhibition on Se concentration and accumulation in B. napus at the seedling stage, but a higher amount (300 mg kg^?1) of S led to a more significant decrease in the mature plants under higher Se conditions, with the maximum reduction in various parts of B. napus reaching 51.3–60.9% and 42.5–53.4%, respectively. The application of S only affected the uptake of Se, and not the translocation of Se; the accumulation of Se in B. napus follows the sequence of pod ≈ stem > rapeseed > root, and the distribution ratio is approximately 1.00:0.97:0.69:0.49. Overall, the application of S alleviated the inhibitory effect on growth caused by excessive Se by reducing the Se concentration in B. napus and facilitating its growth, suggesting that S treatment is a suitable and highly cost-effective method to regulate the content of Se in B. napus.     

Assessment of allelopathic effects of residues of Flaveria bidentis (L.) Kuntze on wheat seedlings

Flaveria bidentis (L.) Kuntze, an invasive plant, poses a serious threat to the structure and function of the native ecosystem in Hebei Provience, China. However, little is known about the allelopathic activity of the residues of this plant species. In this study, the impact of the phytotoxicity of unburnt (UR) and burnt (BR) residues of the exotic invasive weed on the growth of wheat (Triticum aestivvm L.) was assessed. Extracts prepared from both UR and BR reduced the shoot length, root length and dry weight of wheat significantly compared with the control, thereby indicating the presence of some water-soluble allelochemicals in F. bidentis residues. Growth studies conducted in soil amended with UR and BR extracts or residues also revealed phytotoxic effects towards wheat. A significant amount of phenolics was detected in the residue extracts and in residue-incorporated soil. The phenolic content rose with increasing residue concentration, thereby showing their direct involvement in the observed growth inhibition. The inhibition of wheat growth by the burnt residue and its water extracts was similar to that of unburnt residue, so burning it is not a good way to eliminate the allelopathic effects of the residue of F. bidentis on native plants.     

Climate effects on anthocyanin accumulation and composition in the pomegranate (Punica granatum L.) fruit arils

Worldwide pomegranate (Punica granatum L.) production has expanded greatly due to recent evidence on the fruit health attributes. The fruit's unique red color, conferred by anthocyanins, is an imperative sensory quality. Climate effects on the fruit's internal color were reported earlier. The present study investigated the influence of a wide range of temperature regimes (～7-40 °C) on pomegranates' aril anthocyanins. The study included two deciduous and two evergreen accessions as well as desert and Mediterranean orchards. RP-HPLC analysis of the arils' anthocyanins revealed mono- and diglucosylated delphinidins and cyanidins as the major anthocyanins and pelargonidins as minor components. Anthocyanin accumulation changed inversely to the season's temperatures. Cyanidins were generally more abundant but delphinidin accumulation was enhanced in cooler season. Monoglucosylated anthocyanins prevailed at cooler temperatures and subsided during seasonal warming with a concomitant increase in diglucoside proportion. The findings can benefit breeding and agricultural efforts to enhance pomegranate quality, especially in the face of "global warming".     

Alien cytoplasm effects on phytosiderophore release in two spring wheats (Triticum aestivum L.)

Iron (Fe) deficiency is a difficult nutrient problem particularly in crop plants grown on calcareous soils. Recently, phytosiderophore (PS) release has been linked to the ability of graminaceous species and genotypes to withstand Fe-deficiency chlorosis. So enhancing PS release is a critical step to improve iron efficiency of plants grown on iron stressed soils. The effects of alien cytoplasm on PS release in spring wheat were studied by analyzing PS release from twenty wheat genotypes, including two spring wheat 881 and 352-35, and their 18 alloplasmic lines with the participation of cytoplasms from the Aegilops and Triticum species. Different genotypes were grown in iron sufficient and deficient nutrient solution under controlled environmental conditions. PS release rates were determined at two or three days intervals after onset of iron deficiency symptoms by the measurement of iron mobilizing capacity of root exudates from freshly precipitated Fe^III hydroxide. High amounts of phytosiderophores were released from roots of all wheat genotypes without iron supplied, and the amount progressively increased with the development of iron deficiency chlorosis. The results revealed that (1) the release rate of phytosiderophores from roots of common wheat could be considerably influenced by alien cytoplasms. Some alien cytoplasms exerted positive effects, some ones did negative effects, and the other ones had no significant effects. (2) the same alien cytoplasm could affect similarly or oppositely the phytosiderophores release from different wheat. (3) some alien cytoplasms, such as Chinese Spring, Ae. speltoides Tausch and Ae. cylindrica Host showed promising and potential in improving the rate of phytosiderophore release in common wheat. These cytoplasms which showed the desired effect should be given priority in interspecific and intergeneric hybridization to develop and reconstruct the needed wheat cultivars.