A model ensemble approach to determine the humus building efficiency of organic amendments in incubation experiments

Organic amendments are important to sustain soil organic matter (SOM) and soil functions in agricultural soils. Information about the contribution of organic amendments to SOM can be derived from incubation experiments. In this study, data from 72 incubated organic amendments including plant residues, digestates and manure were analysed. The incubation data was compiled from three experimental setups with varying incubation times, soils and incubation temperatures, in which CO₂ release was measured continuously. The analysis of the incubation data was performed with an approach relying on conceptual parts of C-TOOL, CCB, Century, ICBM, RothC and Yasso which are all well-approved first-order carbon models that differ in structure and abstraction level. All models are an approximation of reality, whereby each model differs in understanding of the processes involved in soil carbon dynamics. To accumulate the advantages from each model a model ensemble was performed for each substrate. With the ability of each carbon model to compute the distribution of carbon into specific SOM pools a new approach for evaluating organic amendments in terms of humus building efficiency is presented that, depends on the weighted model fit of each ensemble member. Depending on the organic substrate added to the soil, the time course of CO₂ release in the incubation studies was predicted with different accuracy by the individual model concepts. Averaging the output of the individual models leads to more robust prediction of SOM dynamics. The E_HUM value is easy to interpret and the results are in accordance with the literature.     

Ectopic expression of the serotonin 1c receptor and the triggering of malignant transformation

Neurotransmitter receptors are usually restricted to neuronal cells, but the signaling pathways activated by these receptors are widely distributed in both neural and non-neural cells. The functional consequences of activating a brain-specific neurotransmitter receptor, the serotonin 5HT1c receptor, in the unnatural environment of a fibroblast were examined. Introduction of functional 5HT1c receptors into NIH 3T3 cells results, at high frequency, in the generation of transformed foci. Moreover, the generation and maintenance of transformed foci requires continued activation of the serotonin receptor. In addition, the injection of cells derived from transformed foci into nude mice results in the generation of tumors. The serotonin 5HT1c receptor therefore functions as a protooncogene when expressed in NIH 3T3 fibroblasts.     

Crystal structure of the eukaryotic 40S ribosomal subunit in complex with initiation factor 1

Eukaryotic ribosomes are substantially larger and more complex than their bacterial counterparts. Although their core function is conserved, bacterial and eukaryotic protein synthesis differ considerably at the level of initiation. The eukaryotic small ribosomal subunit (40S) plays a central role in this process; it binds initiation factors that facilitate scanning of messenger RNAs and initiation of protein synthesis. We have determined the crystal structure of the Tetrahymena thermophila 40S ribosomal subunit in complex with eukaryotic initiation factor 1 (eIF1) at a resolution of 3.9 angstroms. The structure reveals the fold of the entire 18S ribosomal RNA and of all ribosomal proteins of the 40S subunit, and defines the interactions with eIF1. It provides insights into the eukaryotic-specific aspects of protein synthesis, including the function of eIF1 as well as signaling and regulation mediated by the ribosomal proteins RACK1 and rpS6e.     

Responding to the challenge of communicable disease in Europe

In the 1960s and 1970s, communicable disease seemed a minor threat, but since then the emergence of new infections and the reemergence of old diseases has provoked a renewed focus on European communicable disease surveillance and control. A "network approach" among European countries has been successful in detecting some international outbreaks, but management and funding aspects remain unresolved. Surveillance outside the European Union has faced new challenges as a result of economic and political change following the collapse of communism. Subsequently, innovative international surveillance schemes are currently being implemented in the countries of Central and Eastern Europe and the former Soviet Union. The challenge for surveillance in Europe is to ensure that it has the capacity to meet both the needs of today and the diseases of the future.     

Helical conformation of alkanes in a hydrophobic cavitand

Alkanes adopt extended conformations in solution that minimize steric interactions and maximize surface area. Folding can reduce the amount of hydrophobic surface exposed to solvent, but sterically unfavorable gauche interactions result. However, we found that the alkyl chains of two common surfactants in aqueous solution adopt helical conformations when bound within a synthetic receptor. The receptor recognizes the helical alkane better than the extended conformation, even though 2 to 3 kilocalories per mole of strain is introduced. The proper filling of space and burial of hydrophobic surface drive the molecular recognition between the receptor and the coiled alkane.     

A modular PIP2 binding site as a determinant of capsaicin receptor sensitivity

The capsaicin receptor (TRPV1), a heat-activated ion channel of the pain pathway, is sensitized by phosphatidylinositol-4,5-bisphosphate (PIP2) hydrolysis after phospholipase C activation. We identify a site within the C-terminal domain of TRPV1 that is required for PIP2-mediated inhibition of channel gating. Mutations that weaken PIP2-TRPV1 interaction reduce thresholds for chemical or thermal stimuli, whereas TRPV1 channels in which this region is replaced with a lipid-binding domain from PIP2-activated potassium channels remain inhibited by PIP2. The PIP2-interaction domain therefore serves as a critical determinant of thermal threshold and dynamic sensitivity range, tuning TRPV1, and thus the sensory neuron, to appropriately detect heat under normal or pathophysiological conditions.     

Apoptosis and necrosis of blood and milk polymorphonuclear leukocytes in early and midlactating healthy cows.

Increased milk somatic cell counts (SCC) are used as an indicator for bovine mastitis. During mastitis, polymorphonuclear leukocytes (PMN) become the predominant cell type. Shortly after parturition, the severity of mastitis is increased and several PMN functions are downregulated. Apoptotic and necrotic processes of PMN could influence SCC and PMN functions. In this study, the percentages of apoptotic and necrotic PMN in blood and milk from early and midlactating healthy cows were compared. Apoptosis and necrosis of PMN were quantified using a dual-color flow cytometric procedure with fluorescein labeled annexin-V (green) and propidium iodide (red). Using this technique three different subpopulations of bovine PMN could be detected: apoptotic cells (high intensive green fluorescence), necrotic cells (high intensive green and high intensive red fluorescence) and viable cells (low intensive green and low intensive red fluorescence). Following a 4 h incubation of blood from both groups of cows at 37 degrees C to induce apoptosis, the mean percentage of apoptotic blood PMN was significantly higher (P < 0.01) in early lactating cows (15.1%, n = 9) compared with midlactating cows (5.3%, n = 10). The mean percentage of necrotic PMN remained lower than 5% in all cows. In contrast to blood, no significant difference was found between the percentage of apoptotic PMN in milk from early (41.2%, n = 7) and midlactating cows (34.0%, n = 8). The percentage of necrotic PMN in milk from early lactating cows (25.9%, n = 7) was significantly higher than that in midlactating cows (14.2%, n = 8) (P < 0.05). Higher percentages of apoptotic as well as necrotic PMN were consistently found in milk compared to blood in all cows. From these results, it can be concluded that spontaneously induced apoptosis was higher in blood PMN from early lactating cows than in blood PMN from midlactating cows. The higher percentage of necrotic milk PMN in early lactating cows than in midlactating cows could be explained by the induction of secondary necrosis.     

Isolation of bovine lymphocytes for beta 2-adrenoceptor determination by means of the radioligand technique: some practical implications

The present investigation was undertaken to demonstrate saturable beta 2-adrenoceptor binding sites on cell membranes of bovine lymphocytes by means of the non-selective antagonist (3H)dihydroalprenolol. Although the classical density gradient centrifugation technique was used as described for the isolation of these cells from human blood, striking differences in binding characteristics were observed. It is suggested that differences in physical properties of blood might be responsible for these phenomena. Since receptor density and affinity of beta 2-adrenoceptors in lymphocytes are used in human medicine (and will be in the future in veterinary medicine) for correlation with several physiological and pathophysiological conditions, attention is drawn to the effect of dilution of blood during the preparation of these cells; in lactating cows, the best results were obtained with the dilution 1:0.5.     

Action of epinephrine on the function of the teat sphincter in the lactating cow

Under continuous IV infusion of oxytocin, milk leakage was elicited in 6 lactating cows with full udders by induction of a vacuum (-30 cm of water) around 1 mammary papilla (teat) with a plethysmographic apparatus. The volumes of milk loss were measured every minute. Epinephrine injected either into the jugular vein (20, 100, and 500 micrograms) or into the external pudic artery (1.5, 7.5, and 37.5 micrograms) induced an increase in milk leakage in 5 cows. This effect could be antagonized by the beta-blocking agent sotalol hydrochloride (0.5 to 4 mg) injected into the external pudic artery. In 1 cow, however, epinephrine given intra-arterially exerted a biphasic effect, small doses inducing stimulation, and large doses evoking inhibition of milk loss. The stimulating effects were blocked by sotalol (2 mg). The inhibiting effects were antagonized by the alpha-blocking agent prazosin (2 mg).