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  • 1
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Elicitors are molecules known to trigger plant defence responses against pathogens. In a search for new sources of eliciting compounds from marine algae, an extract was prepared from green algae, Ulva spp., and its elicitor activity was established on the model legume, Medicago truncatula. When infiltrated into plant tissues or sprayed onto the leaves, this extract induced the expression of the defence-related marker gene PR10 without provoking necrosis. Spraying a solution at 500 µg mL−1 was sufficient to obtain maximum induction of PR10 after 2 d. Using a cDNA array enriched in genes potentially involved in plant defence, the expression of 152 genes was monitored after one or two consecutive treatments. A broad range of defence-related transcripts was found to be up-regulated, notably genes involved in the biosynthesis of phytoalexins, pathogenesis-related proteins and cell wall proteins. In contrast, the expression of primary metabolism-related genes did not change significantly. Consistent with its effect on defence gene expression, it was found that prior treatment of M. truncatula with the Ulva extract protected the plants against subsequent infection by the pathogenic fungus Colletotrichum trifolii.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1436-6215
    Keywords: Key words Estrone – estrogen – obesity – dietary estrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Notes: Summary Background Estrone is a relatively abundant hormone widely distributed in tissues of animal and plant origin. It is a mild estrogen that induces increases in body weigt in experimental animals. The relative abundance of estrone esters in animal tissues suggests that it may also be found in foods, from which it may alter the mechanisms of body weight control. Aim of the study To measure the total estrone content in food and to determine whether this may affect body weight. Methods In the first part of the study, a method was devised for the measurement of total estrone content in food. This was applied to the analysis of estrone content in a variety of food. Finally, hyperlipidic diets (18.6 MJ/kg) with a total estrone content 0.89 ± 0.21 μmol/kg (control group) and 1.37 ± 0.13 μmol/kg (laced with estrone fatty esters) were given to rats during 15 days, in order to determine the influence of dietary estrone on the body mass. Zucker lean (Fa/?) rats weighting initially 200–215 g were used. The total estrone (essentially as fatty esters) content of food was investigated by combining a dried methanol extraction with saponification and measurement of the free estrone evolved through radioimmunoassay. Result The content of estrone was zero in some vegetables, but significant in fruits, meats, and especially fats, both of plant and animal origin. The application of these analyses to a standard recommended diet for humans may result in intakes of more than 1 μmol of estrone per day, a figure comparable to the estrogen production by women. When rats were exposed to a raised estrone content in a fat-rich diet, they significantly increased their body weights, doubling their rate off growth (1.99 g/day) compared with controls (0.81 g/day), but maintaining their plasma composition and the proportions of lipid, water, and protein in their carcasses. Conclusion The widely distributed estrone esters in food and their relatively high concentrations may result in high free hormone intakes in humans. The continued and massive intake of estrone may enhance tissue deposition and lead to obesity.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1435-1536
    Keywords: Key words Glass transition ; Differential scanning calorimetry ; Temperature-modulated differential scanning calorimetry ; Polystyrene ; Heat capacity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The temperature dependence of the relaxation times of the structural relaxation process of polystyrene is determined by temperature-modulated differential scanning calorimetry (TMDSC) and by conventional differential scanning calorimetry (DSC) in the latter by modelling the experimental heat capacity curves measured in heating scans after different thermal histories. The good agreement between both measuring techniques in the temperature interval just above the glass-transition temperature is a guide for the interpretation of the results of the TMDSC technique in the glass-transition region. In addition, the same model applied to DSC scans is used to simulate the TMDSC experiment and the calculated response is compared with the measured scans.
    Type of Medium: Electronic Resource
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