Eutrophication as an impact category

State of the art and research needs for the impact category eutrophication are discussed. Eutrophication is a difficult impact category because it includes emissions to both air and water — both subject to different environmental mechanisms — as well as impacts occurring in different types of terrestrial and aquatic ecosystems. The possible fate processes are complex and include transportation between different ecosystems. In some recent approaches, transportation modelling of air emissions has been included. However, in general, the used characterisation methods do not integrate fate modelling, which is a limitation. The definition of the impact indicator needs further research, too. The inclusion of other nutrients than those typically considered should also be investigated.     

Künstliche Luzerneheubereitungsverfahren in Ungarn

Abstract

An experiment was performed with Rumen Simulation Technique (Rusitec) in which the fermentation of mixed ration of hay (12.8 g/d) and wheat bran (3.2 g/d) was compared with the fermentation of the same diet supplemented with 2.5 and 10 mg monensin. The duration of the experiment was 12 days. During the first six days the fermentation conditions in Rusitec were stabilised. The end products of fermentation and indices of protein synthesis were determined. The energy efficiency of volatile fatty acids (VFA), proportion of fermented hexose energy on VFA energy and on energy of bacterial matter were increased in the presence of monensin. The proportion of fermented hexose energy in methane energy was decreased. Utilization of glucose and production of adenosintriphosphate were not affected. The balance of metabolic H₂ was reduced and this was manifested in decreasing production, utilization and recovery of metabolic H₂. Microbial efficiency expressed per mol ATP (g/mol) was increased by monensin from 7.8 to 12.6. The indices of protein synthesis — protein conversion ratio, degradability of protein and microbial protein synthesis efficiency were increased and non protein utilization ratio decreased in the presence of monensin.

Es wurde ein Versuch nach der Pansensimulationsmethode durchge-führt, in dem die Fermentierung einer gemischten Ration aus Heu (12,8 g/d) und Weizenkleie (3,2 g/d) mit der Fermentierung der gleichen Ration unter Zusatz von 2, 5 und 10 mg Monensin/d verglichen wurde. Die Dauer des Versuchs betrug 12 Tage, wovon die ersten sechs Tage der Stabilisierung der Fermentierungsbedingungen im Rusitec-System dienten.

Es wurden die Endprodukte der Fermentierung und die Kennziffern der Proteinsynthese bestimmt. Die Energieausbeute an Flüchtigen Fettsäuren (FFS), der Energieanteil fermentierter Hexose an der FFS-Energie und der Energie an Bakterienmasse erhöhten sich bei Zusatz von Monensin. Der Energieanteil fermentierter Hexose an der Methanenergie verringerte sich. Die Ausnutzung von Glukose und die Produktion von Adenosintriphosphat waren unbeeinflußt. Die Bilanz von metabolischem H₂ war verringert, was sich im Absinken der Production, der Nutzung und der Wiederauffindung von metabolischem H₂ zeigte. Die mikrobielle Wirksamkeit pro mol ATP (g/mol) erhöhte sich durch Monensin von 7,8 auf 12,6. Die Kennziffern der Proteinsynthese, die Proteinkonversionsrate, die Abbaubarkeit von Protein und die mikrobielle Proteinsynthesewirksamkeit erhöhten sich und die NPN-Nutzungsrate verringerte sich in Gegenwart von Monensin.     

Seasonal dispersal of pests: one surge or two?

Many agricultural pest species occur in seasonal metapopulations with a period of asexual reproduction. We use evolutionary theory to predict timing of dispersal for such species, and identify four sequential phases: no dispersal, dispersal from initially occupied patches, dispersal from later colonized patches, and no dispersal. The third type of phase occurs only when reproductive rates are relatively high; we speculate that this could explain why among aphids there can be either one or two waves of dispersal during a season, depending on the species. Our model also explains other features of aphid biology, including a summer crash in colony size, and a decline in the number of colonies towards the end of each reproductive season. The presence of an additional surge of dispersal becomes more likely as season length increases, and does not require further evolution. This could have profound implications for pest management during future climatic warming.     

Biosynthesis and Genetic Engineering of Lignin

Lignin, a complex heteropolymer of cinnamyl alcohols, is, second to cellulose, the most abundant biopolymer on Earth. Lignification has played a determining role in the adaptation of plants to terrestrial life. As all extracellular polymers, lignin confers rheological properties to plant tissues and participates probably in many other functions in cell and tissue physiology orin cell-to-cell communication. Economically, lignin is very important because it determines wood quality and it affects the pulp and paper-making processes as well as the digestibility of forage crops. For all these reasons the lignin biosynthesis pathway has been the subject of many studies. At present, most genes encoding the enzymes involved in the biosynthesis of lignin have been cloned and characterized. Various recent studies report on the alteration of the expression of these genes by genetic engineering, yielding plants with modified lignin. In addition, several mutants have been analyzed with changes in lignin content or lignin composition resulting in altered properties. Thanks to these studies, progress in the knowledge of the lignin biosynthesis pathway has been obtained. It is now clear that the pathway is more complex than initially thought and there is evidence for alternative pathways. A fine manipulation of the lignin content and/or composition in plants is now achievable and could have important economical and environmental benefits.     

Lysine Succinylation of VBS Contributes to Sclerotia Development and Aflatoxin Biosynthesis in Aspergillus flavus

Aspergillus flavus is a common saprophytic and pathogenic fungus, and its secondary metabolic pathways are one of the most highly characterized owing to its aflatoxin (AF) metabolite affecting global economic crops and human health. Different natural environments can cause significant variations in AF synthesis. Succinylation was recently identified as one of the most critical regulatory post-translational modifications affecting metabolic pathways. It is primarily reported in human cells and bacteria with few studies on fungi. Proteomic quantification of lysine succinylation (Ksuc) exploring its potential involvement in secondary metabolism regulation (including AF production) has not been performed under natural conditions in A. flavus. In this study, a quantification method was performed based on tandem mass tag labeling and antibody-based affinity enrichment of succinylated peptides via high accuracy nano-liquid chromatography with tandem mass spectrometry to explore the succinylation mechanism affecting the pathogenicity of naturally isolated A. flavus strains with varying toxin production. Altogether, 1240 Ksuc sites in 768 proteins were identified with 1103 sites in 685 proteins quantified. Comparing succinylated protein levels between high and low AF-producing A. flavus strains, bioinformatics analysis indicated that most succinylated proteins located in the AF biosynthetic pathway were downregulated, which directly affected AF synthesis. Versicolorin B synthase is a key catalytic enzyme for heterochrome B synthesis during AF synthesis. Site-directed mutagenesis and biochemical studies revealed that versicolorin B synthase succinylation is an important regulatory mechanism affecting sclerotia development and AF biosynthesis in A. flavus. In summary, our quantitative study of the lysine succinylome in high/low AF-producing strains revealed the role of Ksuc in regulating AF biosynthesis. We revealed novel insights into the metabolism of AF biosynthesis using naturally isolated A. flavus strains and identified a rich source of metabolism-related enzymes regulated by succinylation.     

A global synthesis of the effects of diversified farming systems on arthropod diversity within fields and across agricultural landscapes

Agricultural intensification is a leading cause of global biodiversity loss, which can reduce the provisioning of ecosystem services in managed ecosystems. Organic farming and plant diversification are farm management schemes that may mitigate potential ecological harm by increasing species richness and boosting related ecosystem services to agroecosystems. What remains unclear is the extent to which farm management schemes affect biodiversity components other than species richness, and whether impacts differ across spatial scales and landscape contexts. Using a global metadataset, we quantified the effects of organic farming and plant diversification on abundance, local diversity (communities within fields), and regional diversity (communities across fields) of arthropod pollinators, predators, herbivores, and detritivores. Both organic farming and higher in‐field plant diversity enhanced arthropod abundance, particularly for rare taxa. This resulted in increased richness but decreased evenness. While these responses were stronger at local relative to regional scales, richness and abundance increased at both scales, and richness on farms embedded in complex relative to simple landscapes. Overall, both organic farming and in‐field plant diversification exerted the strongest effects on pollinators and predators, suggesting these management schemes can facilitate ecosystem service providers without augmenting herbivore (pest) populations. Our results suggest that organic farming and plant diversification promote diverse arthropod metacommunities that may provide temporal and spatial stability of ecosystem service provisioning. Conserving diverse plant and arthropod communities in farming systems therefore requires sustainable practices that operate both within fields and across landscapes.     

Increased production of low molecular weight recombinant proteins in Escherichia coli.

A general method for obtaining high-level production of low molecular weight proteins in Escherichia coli is described. This method is based on the use of a novel Met-Xaa-protein construction which is formed by insertion of a single amino acid residue (preferably Arginine or Lysine) between the N-terminal methionine and the protein of interest. The utility of this method is illustrated by examples for achieving high-level production of human insulin-like growth factor-1, human proinsulin, and their analogs. Furthermore, highly produced insulin-like growth factor-1 derivatives and human proinsulin analogs are converted to their natural sequences by removal of dipeptides with cathepsin C.     

The impacts of agricultural payments on groundwater quality: Spatial analysis on the case of Slovenia

The European Common Agricultural Policy still follows its primary goals, i.e. quality food at affordable prices and a decent standard of living for farmers, fifty years after its adoption. Moreover, this policy adapts to the changing needs of society and the new challenges, mostly preservation of the environment, nature and biodiversity in rural areas. Although the Common Agricultural Policy receives the largest share of European budget, the funds are decreasing over time, especially direct payments, which aim to provide basic income support to farmers in the European Union. On the other hand, agri-environmental payments are gaining importance. Policy decision-makers should be interested in the question of impacts of growing eco-conditionality of agricultural spending. New insights would help them to be successful in achieving the goals of sustainable agriculture. The purpose of this paper is to estimate the impacts of production support payments and rural development payments on the quality of groundwater. We use the small EU country Slovenia as an example. The baseline indicators are the level of nitrates and pesticides in groundwater, while the impacts were estimated using spatial error model. The results show that direct payments, coupled subsidies and investment grants raise the level of pesticides in groundwater, but do not have any statistically significant impact on the level of nitrates in groundwater. Furthermore, we did not find any statistically significant effects of agri-environmental payments on decrease of groundwater pollution with nitrates. However, our findings revealed that agri-environmental payments are effective in reducing pesticides in groundwater, although only to a limited extent. These results imply a problem of insufficient targeting of agri-environmental measures on the one hand, and suggest that greening of direct payments is necessary and entirely justified.     

Is maximum sustainable yield independent of body size for mammals (and others)?

Summary Provided carrying capacity (K) for non-primate mammals scales with the –0.75 power of adult body weight (W), MSY (in weight) should be approximately one-sixth ofC, whereC is defined byK =CW ^–0.75.