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41.
Fat is commonly added to bakery products to improve eating qualities and extend shelf life. Flour milled from waxy durum grain was incorporated into bread formulations and its effects on crumb softness and loaf volume compared to those of added fat. Low levels of fat (0.1-0.3% of flour weight) softened the bread crumb and increased loaf volume. Most of the softening effects were evident in the crown of the loaves protruding above the tin and a high proportion of the reduction in compression was associated with increased volume. Loaves baked with waxy durum flour were softer than those baked with fat and the softening effects were evident both in the crown of the loaf and at its base where it had been confined within the tin. Waxy durum flour reduces compression independently of increased volume. It is suggested waxy durum flour acts by slowing the migration of water from the gluten phase to the starch phase so maintaining the level of mobile water in the gluten where it acts as a plasticiser. Independent organoleptic assessment of bread quality baked with combinations of waxy durum and fat confirmed the quality enhancing effects of waxy durum flour.  相似文献   
42.
Despite improvement of techniques, semen of 20% of stallions remains unfreezable. Recent studies focused on the impact of reactive oxygen species and oxidant enzymes on semen characteristics. Myeloperoxidase (MPO) is a pro‐oxidant enzyme contained in and released by neutrophils during degranulation or after cell lysis. It is responsible for the formation of hypochlorous acid, a strong oxidant agent, which could damage spermatozoa. The aim of this study was to determine the relation between MPO concentration and characteristics of frozen semen from stallions. Thirty‐five straws from different stallions were analysed. Post‐thawing spermatozoal concentration, and progressive and total motility were determined by Computer‐Assisted Semen Analysis. Freezability was determined according to post‐thawing progressive motility (above or below 15%). Percentage of alive spermatozoa and abnormal forms was determined after Eosin–Nigrosin and Diff‐Quick® staining, respectively. Post‐thawing MPO concentration was measured by enzyme‐linked immunosorbent assay (ELISA). Our study shows that frozen thawed semen contains large amounts of free MPO. We also observed that post‐thawing MPO ELISA assay can be used as an indicator of equine semen freezability. High MPO concentration samples showed lower total and progressive motility. A higher proportion of abnormal head shape associated with acrosome reaction was observed in our late examinations of the high concentration MPO group. Our results show that MPO adversely affects total and progressive motility of equine semen. A negative correlation between normal motile forms and MPO concentration was also observed. The effect of MPO on dead or abnormal forms remains to be precised.  相似文献   
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44.
Sainfoin (Onobrychis viciifolia Scop.) is a perennial forage legume that possesses beneficial properties in the context of sustainable agriculture. In order to initiate a pre-breeding programme, we have assembled a germplasm collection of O. viciifolia from many geographic regions, as well as a collection of Onobrychis species that might be crossed with O. viciifolia to improve its biological and agronomic properties. The objective of this study was to obtain DNA sequences from a representative sample of these accessions in order to characterise their genetic diversity and to assess the robustness of the Onobrychis taxonomy. Because of potential problems with copurification of tannins and polyphenols from Onobrychis leaf tissue, three methods for DNA extraction were assessed and the most appropriate one identified. DNA sequences were obtained for the nuclear internal transcribed spacer region and the trnH-psbA and trnT-trnL intergenic spacers of the chloroplast genome. Neighbour joining trees were constructed and accessions were assigned to operational taxonomic units. The results indicated that there is substantial genetic diversity among Onobrychis species. Redundancies in species nomenclature were identified, as well as possible overlap between some of the sections into which the Onobrychis genus has been divided. A genetic distinction was apparent between O. viciifolia accessions from western Europe and those from eastern Europe and Asia, reflecting a similar division based on agronomic properties. Recognition of these different though related germplasms will be valuable in the design of breeding programmes for the rational improvement of sainfoin as a forage crop for sustainable agriculture.  相似文献   
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Like other influenza A viruses, equine influenza virus undergoes antigenic drift. It is therefore essential that surveillance is carried out to ensure that recommended strains for inclusion in vaccines are kept up to date. Here we report antigenic and genetic characterisation carried out on equine influenza virus strains isolated in North America and Europe over a 2-year period from 2008 to 2009. Nasopharyngeal swabs were taken from equines showing acute clinical signs and submitted to diagnostic laboratories for testing and virus isolation in eggs. The sequence of the HA1 portion of the viral haemagglutinin was determined for each strain. Where possible, sequence was determined directly from swab material as well as from virus isolated in eggs. In Europe, 20 viruses were isolated from 15 sporadic outbreaks and 5 viruses were isolated from North America. All of the European and North American viruses were characterised as members of the Florida sublineage, with similarity to A/eq/Lincolnshire/1/07 (clade 1) or A/eq/Richmond/1/07 (clade 2). Antigenic characterisation by haemagglutination inhibition assay indicated that the two clades could be readily distinguished and there were also at least seven amino acid differences between them. The selection of vaccine strains for 2010 by the expert surveillance panel have taken these differences into account and it is now recommended that representatives of both Florida clade 1 and clade 2 are included in vaccines.  相似文献   
47.
Sainfoin (Onobrychis viciifolia Scop.) is a perennial forage legume that possesses beneficial properties in the context of sustainable agriculture. A germplasm collection of O. viciifolia was assembled from many geographic regions, as well as a collection of Onobrychis species that might be crossed with O. viciifolia to improve its biological and agronomic properties. The objective of the present study was to obtain cytological information for a broad range of O. viciifolia varieties and related species, in order to confirm and extend previous findings. The study set was 143 accessions of O. viciifolia as well as 34 accessions of 17 other species from the Onobrychis genus. Three of the O. viciifolia accessions were diploid (2n = 2x = 14) and the remainder tetraploid (2n = 4x = 28). Chromosomes were <5 μm in length. Among the other Onobrychis species, roughly half were found to be diploid and the other half tetraploid, with two species, O. arenaria (Kit.) DC. and O. alba subsp. laconica (Orph. ex Boiss.) Hayek, including a mixture of diploid and tetraploid accessions. The basic number of chromosomes was seven, except for O. aequidentata (Sm.) d’Urv. and O. crista-galli Lam., where it was eight. The 2C value for O. viciifolia was estimated at 2.5 pg. These cytological data will be valuable as part of a pre-breeding programme aimed at the eventual production of improved O. viciifolia varieties for use in sustainable agriculture.  相似文献   
48.
  • ? It is agreed that climate (precipitation and temperature) influences the distribution of plant species. Near the margins of a species’ natural range, climate becomes limiting to physiological processes. There, climate change may be expected to have a significant impact on tree growth and the species’ ranges may be altered.
  • ? In order to assess what influence climate change could exert on the distribution of pine species at their margin, radial growth trends in ring-width chronologies over the last century were analysed. In the French Mediterranean area where climate change is characterized by increased temperature, forest plots were selected along an altitudinal transect on the north-facing slope of the Sainte-Baume mountain (Bouches-du-Rhône, France) where the ranges of Pinus sylvestris and Pinus halepensis overlap.
  • ? Two growth patterns were identified. For P. halepensis, radial growth has increased at all altitudes indicating that climate change has improved growth conditions of this species near the margin of its ecological range. For P. sylvestris, radial growth has increased only at low altitudes and even decreased at high altitudes.
  • ? It must be deduced that the growth changes observed cannot be generalised either at the species level or at the geographical level and must be interpreted with great caution.
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    49.
  • ? Water availability is one of the main factors explaining flora composition and growth in Mediterranean regions, where it may decline with climate change.
  • ? Our goal was to develop a model for forest site assessment in Mediterranean environments, focusing on water availability to assess potential vegetation composition and productivity in any places, whatever their level of disturbance.
  • ? We designed a statistical model, using global climatic and geographic variables, as well as detailed local topographic and edaphic variables, to compute a bioclimatic index for Mediterranean forest environments. This model was calibrated in France with a flora index from 325 old forests. The model explained 80.3% of the flora index variance. The method fills a gap in existing models, bridging scales from the region to forest sites.
  • ? Beyond its theoretical aspect, it was designed to allow practical tools to be derived from it for decision-making and management, such as the assessment of climate change impact on vegetation, and of forest productivity. Its development and adaptation is possible in other Mediterranean regions, and in any region where water is one of the main limiting factors.
  •   相似文献   
    50.
    Natural products as sources for new mechanisms of herbicidal action   总被引:6,自引:0,他引:6  
    New mechanisms of action for herbicides are highly desirable to fight evolution of resistance in weeds, to create or exploit unique market niches, and to cope with new regulatory legislation. Comparison of the known molecular target sites of synthetic herbicides and natural phytotoxins reveals that there is little redundancy. Comparatively little effort has been expended on determination of the sites of action of phytotoxins from natural sources, suggesting that intensive study of these molecules will reveal many more novel mechanisms of action. Examples of natural products that inhibit unexploited steps in the amino acid, nucleic acid, and other biosynthetic pathways are given. AAL-toxin, hydantocidin, and various plant-derived terpenoids are discussed. Strategies and potential pitfalls of using natural products as leads for new herbicide classes are summarized.  相似文献   
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