Swedish University of Agricultural Sciences

About: Swedish University of Agricultural Sciences is a education organization based out in Uppsala, Sweden. It is known for research contribution in the topics: Population & Soil water. The organization has 13510 authors who have published 35241 publications receiving 1414458 citations. The organization is also known as: Sveriges Lantbruksuniversitet & SLU.

Epistasis and the release of genetic variation during long-term selection.

Abstract: It is an enigma how long-term selection in model organisms and agricultural species can lead to marked phenotypic changes without exhausting genetic variation for the selected trait. Here, we show that the genetic architecture of an apparently major locus for growth in chicken dissects into a genetic network of four interacting loci. The interactions in this radial network mediate a considerably larger selection response than predicted by a single-locus model.

Structure of a cephalosporin synthase

Abstract: Penicillins and cephalosporins are among the most widely used therapeutic agents. These antibiotics are produced from fermentation-derived materials as their chemical synthesis is not commercially viable. Unconventional steps in their biosynthesis are cat

An ecosystem-level perspective of allelopathy

Abstract: Allelopathy is an interference mechanism by which plants release chemicals which affect other plants; while it has often been proposed as a mechanism for influencing plant populations and communities, its acceptance by plant ecologists has been limited because of methodological problems as well as difficulties of relating the results of bioassays used for testing allelopathy to vegetation patterns in the field. Here we argue that the concept of allelopathy is more appropriately applied at the ecosystem-level, rather than the traditional population/community level of resolution. Firstly, we consider the wide ranging effects of secondary metabolites (widely regarded as allelochemicals) on organisms and processes which regulate ecosystem function, including herbivory, decomposition and nutrient mineralization. It is apparent that plants with allelopathic potential against other organisms induce net changes in ecosystem properties, which may in turn impact upon the plant community in the longer term. We then illustrate these concepts using two contrasting examples of how invasive plant species with allelopathic potential may alter ecosystem properties through the production of secondary metabolites, i.e. Carduus nutans (nodding thistle) in New Zealand pastures and Empetrum hermaphroditum (crowberry) in Swedish boreal forests. In both cases the production of secondary metabolites by the invasive species induces important effects on other organisms and key processes, which help determine how the ecosystem functions and ultimately the structure of the plant community. These examples help demonstrate that the concept of allelopathy is most effectively applied at the ecosystem-level of resolution, rather than at the population-level (i.e. plant-plant interference).

Evaluation of antioxidant activities of rosehip ethanol extracts in different test systems

Abstract: Rosehip extracts of 18 samples representing six taxa in the genus Rosa were evaluated for antioxidant activities by use of different test systems. The ferric-reducing antioxidant power (FRAP) and Trolox-equivalent antioxidant capacity (TEAC) of the crude extracts ranged from 983.4 to 2187.1 µmol FRAP g−1 dry matter and from 457.2 to 626.2 µmol TEAC g−1 dry matter. The high antioxidant capacity was related to high contents of phytonutrients. The overall mean of antioxidants was 23.23 mg g−1 total carotenoids and 76.26 mg g−1 total phenolics. The phenolic component made a major contribution to the total antioxidant activities in both assays (overall mean was 90.5% and 75.7%), whereas the ascorbate made a minor contribution (8.6% and 16.9%) and the lipophilic component made an even smaller one (0.9% and 7.3%). However, the lipophilic component was the most effective when the comparison was based on the ratio of antioxidant activity to content of antioxidants. The crude extracts exhibited 50.9% (46.6–60.3%) inhibitory effect against the lipid peroxidation induced by 2,2′-azobis(2,4-dimethylvaleronitrile) (AMVN) and 85.0% (80.1–90.2%) inhibition in 2,2′-azobis(2-amidinopropane)hydrochloride (AAPH) assay at a concentration of 250 µg ml −1. Ascorbate acted as an antioxidant in both peroxy radical-induced lipid peroxidations, but as a pro-oxidant in the metal ion-induced lipid peroxidation. The crude extracts showed a large inhibitory effect in the ferric ion-induced lipid peroxidation and caused 83.7% inhibition at a concentration of 25 µg ml −1 dried rosehip powder. © 2000 Society of Chemical Industry