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.

Receptor binding studies disclose a novel class of high-affinity inhibitors of the Escherichia coli FimH adhesin

Abstract: Summary Mannose-binding type 1 pili are important virulence factors for the establishment of Escherichia coli uri- nary tract infections (UTIs). These infections are initi- ated by adhesion of uropathogenic E. coli to uroplakin receptors in the uroepithelium via the FimH adhesin located at the tips of type 1 pili. Blocking of bacterial adhesion is able to prevent infection. Here, we pro- vide for the first time binding data of the molecular events underlying type 1 fimbrial adherence, by crys- tallographic analyses of the FimH receptor binding domains from a uropathogenic and a K-12 strain, and affinity measurements with mannose, common mono- and disaccharides, and a series of alkyl and aryl man- nosides. Our results illustrate that the lectin domain of the FimH adhesin is a stable and functional entity and that an exogenous butyl a a a - D -mannoside, bound in the crystal structures, exhibits a significantly better affinity for FimH (K d = 0.15 m m m M) than mannose (K d = 2.3 m M). Exploration of the binding affinities of a - D -mannosides with longer alkyl tails revealed affin- ities up to 5 nM. Aryl mannosides and fructose can also bind with high affinities to the FimH lectin domain, with a 100-fold improvement and 15-fold reduction in affinity, respectively, compared with mannose. Taken together, these relative FimH affini- ties correlate exceptionally well with the relative con- centrations of the same glycans needed for the inhibition of adherence of type 1 piliated E. coli . We foresee that our findings will spark new ideas and initiatives for the development of UTI vaccines and anti-adhesive drugs to prevent anticipated and recur- rent UTIs.

Ecology of Denitrifying Prokaryotes in Agricultural Soil

Abstract: Denitrification is a microbial respiratory process during which soluble nitrogen oxides are used as an alternative electron acceptor when oxygen is limiting. It results in considerable loss of nitrogen, which is the most limiting nutrient for crop production in agriculture. Denitrification is also of environmental concern, since it is the main biological process responsible for emissions of nitrous oxide, one of the six greenhouse gases considered by the Kyoto protocol. In addition to natural variations, agroecosystems are characterized by the use of numerous practices, such as fertilization and pesticide application, which can influence denitrification rates. This has been widely documented in the literature, illustrating the complexity of the underlying mechanisms regulating this process. In the last decade, however, application of molecular biology approaches has given the opportunity to look behind denitrification rates and to describe genes, transcripts, and enzymes responsible for the process. In order to reduce denitrification in arable soil, it is important to understand how different factors influence denitrification and how the denitrifier community structure is related to in situ activity. This chapter focuses on the impact of natural events as well as agricultural practices on denitrifying microorganisms.

The underappreciated potential of peatlands in global climate change mitigation strategies.

Abstract: Soil carbon sequestration and avoidable emissions through peatland restoration are both strategies to tackle climate change. Here we compare their potential and environmental costs regarding nitrogen and land demand. In the event that no further areas are exploited, drained peatlands will cumulatively release 80.8 Gt carbon and 2.3 Gt nitrogen. This corresponds to a contemporary annual greenhouse gas emission of 1.91 (0.31–3.38) Gt CO2-eq. that could be saved with peatland restoration. Soil carbon sequestration on all agricultural land has comparable mitigation potential. However, additional nitrogen is needed to build up a similar carbon pool in organic matter of mineral soils, equivalent to 30–80% of the global fertilizer nitrogen application annually. Restoring peatlands is 3.4 times less nitrogen costly and involves a much smaller land area demand than mineral soil carbon sequestration, calling for a stronger consideration of peatland rehabilitation as a mitigation measure.

How understanding aboveground–belowground linkages can assist restoration ecology

Abstract: The topic of aboveground–belowground linkages has seen much recent activity, resulting in several conceptual advances regarding plant–soil feedbacks, multitrophic interactions, and how organisms drive ecosystem processes. Although restoration ecology has been rapidly evolving as a scientific discipline, the principles that have developed regarding aboveground–belowground linkages have yet to be thoroughly integrated into it. In this review, we conceptually integrate the role of aboveground–belowground linkages with the principles of restoration ecology through a framework that transcends multiple levels of ecological organization, and illustrate its application through three examples: restoration of abandoned land, reversal of biological invasions, and restoration of natural disturbances. We conclude that this integration can greatly assist restoration ecology, through aiding identification of effective invention practices and prediction of ecosystem recovery.

The C:N:P stoichiometry of autotrophs: Theory and observations

Abstract: Evolution has set biochemical constraints on the chemical composition of living organisms. These constraints seem to lead to increases in N : C and P : C ratios with increasing relative growth rate for all types of organisms. The N : P ratio also seems to decrease with relative growth rate for heterotrophs whereas autotrophs may show a more complex behaviour. Here I will show that, from biochemical considerations, N : C should increase linearly and P : C quadratically with relative growth rate in autotrophs with the consequence that N : P increases at low relative growth rates, passes a maximum and then decreases at high relative growth rates. These predictions are verified against observations for a freshwater alga (Selenastrum minutum) and a tree seedling (Betula pendula). Changes in temperature, light or other factors that affect the growth rate of autotrophs interact with nutrient supply in such a way that there are no simple rules for as to how N : P will change.