Enhancement of gilthead seabream (Sparus aurata) larval growth by dietary vitamin E in relation to two different levels of essential fatty acids

The objective of this study was to determine the effect of dietary vitamin E on gilthead seabream (Sparus aurata) growth and survival, at two different highly unsaturated fatty acids (HUFAs) levels. Eighteen days old gilthead seabream larvae were fed four formulated experimental diets combining two different dietary levels of HUFAs (M: medium 2.5 + 1.5, DHA + EPA, H: high 5 + 2.5 DHA + EPA g per 100 g) with two different levels of vitamin E (M: medium 540 mg kg^?1, H: high 2900 mg kg^?1): MM, MH, HM, HH (HUFA/vitamin E). After 2‐week feeding trial, the average survival rate was 52.6% and there were no significant differences found among treatments. Increase in vitamin E up to high level markedly improved larval growth, particularly when dietary HUFA levels were lower, suggesting a higher protection value when these fatty acids are more limiting. At medium dietary HUFA levels, increase in vitamin E from medium to high level enhanced larval growth performance in terms of total length. Moreover, increase in vit E enhanced HUFAs content in the larval polar lipids denoting the anti‐oxidative effect of vitamin E.     

High throughput phenotyping for aphid resistance in large plant collections

ABSTRACT: BACKGROUND: Phloem-feeding insects are among the most devastating pests worldwide. They not only cause damage by feeding from the phloem, thereby depleting the plant from photo-assimilates, but also by vectoring viruses. Until now, the main way to prevent such problems is the frequent use of insecticides. Applying resistant varieties would be a more environmental friendly and sustainable solution. For this, resistant sources need to be identified first. Up to now there were no methods suitable for high throughput phenotyping of plant germplasm to identify sources of resistance towards phloem-feeding insects. RESULTS: In this paper we present a high throughput screening system to identify plants with an increased resistance against aphids. Its versatility is demonstrated using an Arabidopsis thaliana activation tag mutant line collection. This system consists of the green peach aphid Myzus persicae (Sulzer) and the circulative virus Turnip yellows virus (TuYV). In an initial screening, with one plant representing one mutant line, 13 virus-free mutant lines were identified by ELISA. Using seeds produced from these lines, the putative candidates were re-evaluated and characterized, resulting in nine lines with increased resistance towards the aphid. CONCLUSIONS: This M. persicae-TuYV screening system is an efficient, reliable and quick procedure to identify among thousands of mutated lines those resistant to aphids. In our study, nine mutant lines with increased resistance against the aphid were selected among 5160 mutant lines in just 5 months by one person. The system can be extended to other phloem-feeding insects and circulative viruses to identify insect resistant sources from several collections, including for example genebanks and artificially prepared mutant collections.     

瘤胃乙酸与丙酸摩尔比例的改变对瘤胃发酵及血液指标的影响

通过向瘤胃灌注乙酸：丙酸：丁酸的摩尔比例分别为75：15：10，65：25：10，55：35：10和45：45：10溶液，并在连续灌注的作用下，以期达到最终改变瘤胃液中乙酸：丙酸：丁酸摩尔比例的目的。研究表明：（1）随着灌注液中丙酸浓度的提高，最终瘤胃液中丙酸的比例增加，乙酸的比例逐渐下降，与对照组差异显著（P＜0.05），丁酸的摩尔比例无论与对照组，还是各处理间均无差异；（2）向瘤胃灌注的VFA溶液提供高于维持能量水平30％以上的能量，使瘤胃中总的VFA浓度、VFA产生速率、丙酸的产生速率及VFA的总产量均显著增加（P＜0.01）；但是对基础混合日粮的干物质（DM）、有机物（OM）、中洗纤维（NDF）、酸洗纤维（ADF）、半纤维素（HCF）等养分的消化率不构成显著影响；（3）当灌注溶液中丙酸所占摩尔比例增加到35％，粪氮和尿氮的排出量显著减少（P＜0.05），从而提高日粮氮的沉积能力。进一步研究表明，当灌注液中丙酸的摩尔比例进一步提高至45％时，血糖浓度及胰岛素的浓度才显著增加（P＜0.05）；但胰岛素与胰高血糖素的比值对于不同的处理或对照组，基本保持稳定。     

Analysis on the Disposal of the Industrial Solid Waste in the Three Gorges Region

The second step of water storage for Three Gorges Reservoir will be executed in Jue,2003. Because there is still a large quantity of industrial solid waste(ISW) dumped on the reservoir bottom where should be cleaned before water storage and wastes should be disposed. After a full investigation and analyze, the total amount of ISW in the Chongqing reservoir area is about 1.66 million tons. According the principles of safe, economical and reliable, this paper describes the ISW's treatment. The ordinary ISW which is harmless and non toxic after identification should be treated on-site, the ISW that exceeds the national standards should be removed and be disposed in the landfill, and the hazardous waste should be removed for disposition or storage.     

Analyses of Interlayer Stresses and Strain Transfer in Smart Laminated Structures

A new model is proposed to analyze the strain/stress transfer relation between host materials and piezoceramic sensors/actuators under bending and axial stress loading. The finite thickness of the adhesive is taken into account. The physical layers of the piezoceramic, adhesive and structure material are further subdivided into thinner layers as fine as necessary in order to improve the accuracy of stress analysis. In each thin layer the in-plane stresses are assumed to vary linearly across the thickness. By satisfying equilibrium equations, constitutive equations and displacement-strain relations, all components of stress, strain and displacement can be expressed as functions of the in-plane forces and the moments of the thin layers. The differential equations governing the in-plane forces and the moments are obtained. Then, this analytical model is used to predict strain transfer from the structure material to the sensor. It is found, both experimentally and theoretically, that the axial strain of the host material is considerably larger than the strain of the sensor, which is directly related to the output voltage. By introducing the so-called strain transfer factor, a relationship between the output voltage of the sensor and the strain of the measured material is derived. The model is used to predict interlayer stress distributions and strain transfer, which are induced by actuator strain. The result was compared with existing experiments and FEM. There is stress concentration between the actuator and adhesive around the edge of the smart structures, which may cause debonding under high stress loading.     

In vitro culture variation of wheat and rye caused by genes affecting plant growth habit in vivo

Summary The influence of genes affecting the plant growth habit in wheat (Rht8 and Ppd1) and rye (ct1 and ct2) on tissue culture response was studied using immature embryos. Whereas the semi-dwarfing gene Rht8 seems to promote only a minor effect, the day-length sensitive allele ppd1 determined a major increase in callus growth and regeneration ability. With regards to their tissue culture efficiency, the four alleles studied could be ranked as follows: ppd1>Rht8>rht8>Ppd1.In contrast to wheat, the GA insensitive semi-dwarfing genes of rye (ct1 and ct2) appear not to influence in vitro response.     

Suitability of Wastes from Olive-Oil Industry for Initial Reclamation of a Pb/Zn Mine Tailing

An incubation experiment was conducted to evaluate the ameliorating role of two organic amendments—olive-mill solid wastes and compost from olive-mill solid wastes- in the ecological reclamation of a lead/Zn-mine tailing collected in southern Spain. Four enzymatic activities (dehydrogenase, β-glucosidase, urease and phosphatase) and soluble and AB-DTPA extractable Pb and Zn and were periodically determined. High concentrations of Pb (5394 mg kg^?1) and Zn (9607 mg kg^?1), mainly in insoluble forms, were recorded in the lead/zinc-mine tailing, as well as very low biochemical activity. Application of the compost from olive-mill solid waste stimulated microbial activity and the biogeochemical cycles into the mine tailing because of the initially increased dehydrogenase, β-glucosidase and urease activities, which tended to decline or remained constant during the incubation period. By contrast, these enzyme activities were scarcely affected by the incorporation of the olive-mill solid wastes because this olive-organic amendment contains extractable polyphenols (36 g kg^?1), which inhibit these enzyme activities. Phosphatase activity was enhanced by the application of both olive-organic amendments, especially when the olive-mill solid waste was added to the mine tailing. Amounts of soluble and AB-DTPA-extractable Pb and Zn in the mine tailing were increased by the application of the olive-mill solid waste, and to a lesser degree, by the compost from this olive waste. This fact could restrict the use of these olive-organic amendements as useful materials in reclamation of lead/zinc-mine tailings. Nevertheless, the increases of available lead and zinc would represent an advantage where Pb/Zn-mine tailings are reclaimed by phytoextraction, effectively reducing the metal pollution in these mining wastes.     

In vitro screening and QTL analysis for drought tolerance in diploid potato

Drought stress is a major abiotic constraint limiting crop production worldwide. Screening for drought tolerance and the traits that enhance drought tolerance is not straightforward in large mapping populations. In this study, we investigated the possibility of screening a mapping population in vitro for PEG-induced water deficit stress and recovery potential. We have measured several shoot and root growth parameters or traits in the C × E diploid potato mapping population. Significant variation was observed for genotype-specific responses to water deficit and recovery potential. Genetic variation and heritability estimates were high to very high for the measured traits depending on growth conditions. In order to identify potato QTLs for drought tolerance and recovery potential an SNP marker-rich integrated linkage map was used. A total of 23 QTLs were detected under control, stress and recovery treatments explaining 10.3–22.4% of the variance for each phenotypic trait. Among these, 10 QTLs were located on chromosome 2. Three QTLs involved in the important trait root to shoot ratio were identified on linkage groups 2, 3 and 8. These loci explained together 41.1% of the variance for this trait, and may be breeding targets for stress tolerance and yield in the field as well. The SNP markers derived from EST sequences underlying these QTLs led to the identification of putative candidate genes for further study in potato. This study constitutes the first knowledge of in vitro screening of a mapping population for drought tolerance in potato.     

Adaptive phenotypic plasticity in response to climate change in a wild bird population

Rapid climate change has been implicated as a cause of evolution in poorly adapted populations. However, phenotypic plasticity provides the potential for organisms to respond rapidly and effectively to environmental change. Using a 47-year population study of the great tit (Parus major) in the United Kingdom, we show that individual adjustment of behavior in response to the environment has enabled the population to track a rapidly changing environment very closely. Individuals were markedly invariant in their response to environmental variation, suggesting that the current response may be fixed in this population. Phenotypic plasticity can thus play a central role in tracking environmental change; understanding the limits of plasticity is an important goal for future research.     

意向性建构原理与读者理论

现象学哲学的“意向性建构”原理的实质意义给与 :主体建构对象就是给与对象意义。这是讲求读者建构 (再创造 )文本意义一路文学理论的哲学基础