Porcine CD8αdim/-NKp46high NK cells are in a highly activated state

Natural Killer (NK) cells play a crucial role in the early phase of immune responses against various pathogens. In swine so far only little information about this lymphocyte population exists. Phenotypical analyses with newly developed monoclonal antibodies (mAbs) against porcine NKp46 recently revealed that in blood NKp46^- and NKp46⁺ cells with NK phenotype exist with comparable cytotoxic properties. In spleen a third NKp46-defined population with NK phenotype was observed that was characterised by a low to negative CD8α and increased NKp46 expression. In the current study it is shown that this NKp46^high phenotype was correlated with an increased expression of CD16 and CD27 compared to the CD8α⁺NKp46^- and NKp46⁺ NK-cell subsets in spleen and blood. Additionally NKp46^high NK cells expressed elevated levels of the chemokine receptor CXCR3 on mRNA level. Functional analyses revealed that splenic NKp46^high NK cells produced much higher levels of Interferon-γ and Tumor Necrosis Factor-α upon stimulation with cytokines or phorbol-12-myristate-13-acetate/Ionomycin compared to the other two subsets. Furthermore, cross-linking of NKp46 by NKp46-specific mAbs led to a superior CD107a expression in the NKp46^high NK cells, thus indicating a higher cytolytic capacity of this subset. Therefore porcine splenic NKp46^high NK cells represent a highly activated subset of NK cells and may play a profound role in the immune surveillance of this organ.     

Nitrat-Verlagerung in Auenböden unter organischer und konventioneller Bewirtschaftung — Meßergebnisse,Modellierungen und Bilanzen

Nitrate transport in soils of a river flood plain under organic and conventional farming — analytical results, modeling and balances Over a period of two years the transport of nitrate was investigated in Fluvi-Eutric Cambisols of a river flood plain of the Rhine tributary Sieg (Nordrhein-Westfalen, Germany). The soils were cultivated according to organic and conventional farming systems. Time series of NO₃ concentrations in soil solutions sampled by ceramic cups down to a depth of 180 cm are given. The interpretation of the results was possible by model calculations using the model DELPHI, which had been calibrated before by tracer experiments. N-mineralization and N-leaching were quantified. For different crop residues reaction coefficients for the mineralization of the easily decomposed organic material were calculated. They were extremely high for bean residues (19.0 × 10¹²) × exp (-9800/T) and mustard-vetch residues (12.0 × 10¹² × exp (-9800/T). The lowest reaction coefficient of 3.0 × 10¹² × exp (-9800/T) was calculated for the decomposition process during winter time. For the two farming systems a detailed N-balance was calculated. It is shown that under conventional farming over a time period of two years 199 kg N/ha were leached. Within the same period 53 kg N/ha were leached under organic farming. These differences depend in part on different crop rotation. Especially intercropping on the organically cultivated plots reduced the leaching of nitrate.     

Excretion of loline alkaloids in urine and faeces of sheep dosed with meadow fescue (Festuca pratensis) seed containing high concentrations of loline alkaloids

Abstract

AIM: To determine the effect of oral dosing of sheep with loline alkaloids on their excretion in urine and faeces, and to monitor for any toxic effects.

METHODS: In Experiment 1, six 9-month-old ewe lambs were given a single oral dose of loline alkaloids (52 mg/kg bodyweight (BW); acute exposure) as a suspension of ground meadow fescue (Festuca pratensis) seed in water. In Experiment 2, on six consecutive days, six ewe lambs were given three doses of loline (68 mg/kg BW/day; chronic exposure). Blood was collected at variable intervals up to 72 h in Experiment 1, and up to 8 days in Experiment 2, for haematology and measurement of alkaline phosphatase, aspartate aminotransaminase, creatine kinase and γ-glutamyl transferase in plasma. Urine and faecal samples were collected at similar times for measurement of creatinine in urine and loline alkaloid analysis. A post mortem with histopathology was carried out on two animals at the end of each experiment.

RESULTS: The loline alkaloids, N-acetyl norloline, N-formyl loline, N-acetyl loline, N-methyl loline and loline base were detected in urine within 15 minutes after the single dosing. N-formyl loline and loline base were the predominant metabolites in urine in both experiments. The total quantity of lolines excreted in both urine and faeces was 10% and 4% of the amount dosed in Experiments 1 and 2, respectively. In both experiments, the clinical chemistry parameters in blood and urine were within normal ranges. Post-mortem and histopathological examination did not show any abnormalities.

CONCLUSIONS: This is the first report of loline alkaloid profiles in both urine and faeces of sheep. The appearance of loline alkaloids and the loline base in urine within 15 minutes suggests rapid uptake, metabolism and excretion. Loline alkaloids were non-toxic to sheep at the concentrations they are exposed to under New Zealand grazing conditions. The low recovery of loline alkaloids in urine and faeces in the absence of toxicity signs suggests lolines are extensively metabolised; probably to forms other than N-formyl loline, N-methyl loline, N-acetyl loline, N-acetyl norloline, and loline base in the digestive tract of sheep prior to absorption, and/or in the liver or other tissues following absorption.     

Coloured potatoes (Solanum Tuberosum L.) – Anthocyanin Content and Tuber Quality

Anthocyanins gain more and more importance as natural colourants. Besides many other plant species, coloured potatoes could serve as a potential source. Therefore, 27 potato cultivars and four breeding clones of different origin were analysed for their anthocyanin contents in fresh weight (fw). On average the highest amounts of anthocyanins were found in the skin (0.65 g kg⁻¹ fw) of potatoes. The corresponding values of samples taken from whole tubers (0.31 kg⁻¹ fw) and flesh (0.22 kg⁻¹ fw) were significantly lower (p<0.03). The analysis revealed considerable differences in the amounts of anthocyanins between the 31 cultivars/breeding clones. Among them ȁ8Peru Purpleȁ9 revealed the highest anthocyanin content in the skin with 2.96 g kg⁻¹ fw. A similar high value was reached by ȁ8Violettfleischigeȁ9 and clone 1.81.202–92 N. Also for the other two types of samples, flesh and whole tubers, these three genotypes exhibited the highest level of anthocyanins. Interestingly, different rates of nitrogen fertilization at 100 and 200 kg ha⁻¹ had no significant effect on the pigment content of potatoes. The same was observed with respect to the year or the location of plant growth. There were also no significant changes in the anthocyanin contents of tubers during storage for 135 days. In dry matter, starch and protein contents the coloured potato cultivars/breeding clones were comparable with traditional cultivars. Further tests have shown that the glycoalkaloids were mainly localized in the skin of coloured potatoes.     

Solar wind origin in coronal funnels

The origin of the solar wind in solar coronal holes has long been unclear. We establish that the solar wind starts flowing out of the corona at heights above the photosphere between 5 megameters and 20 megameters in magnetic funnels. This result is obtained by a correlation of the Doppler-velocity and radiance maps of spectral lines emitted by various ions with the force-free magnetic field as extrapolated from photospheric magnetograms to different altitudes. Specifically, we find that Ne7+ ions mostly radiate around 20 megameters, where they have outflow speeds of about 10 kilometers per second, whereas C3+ ions with no average flow speed mainly radiate around 5 megameters. Based on these results, a model for understanding the solar wind origin is suggested.     

Nutritive value of ensiled maize stover from nine different varieties harvested at three different stages of maturity

Nutrient composition and digestibility of stover contribute markedly to the nutritive value of forage maize in cattle feeding. Low stover digestibility limits the quality of whole plant maize silage (WPMS) and should therefore be prevented by optimizing management of WPMS production. A project was carried out to analyse nutrient composition and ruminal nutrient degradability of ensiled stover of nine different current maize varieties, which were planted in 3 years and harvested at three maturity stages (50, 55 and 60% ear dry‐matter [DM] content). Variety and harvest date had a significant impact (p < 0.05) on crude protein (CP) and metabolizable energy content, whereas fibre content and non‐fibre components were not affected by these factors. In contrast, the potential and effective degradability (ED) of organic matter (OM), CP and neutral detergent fibre (NDF) were significantly influenced by variety and harvest date. The ED5 (ED at 5% per hour passage rate) of different varieties ranged from 22.9% to 29.3% for OM, from 66.2% to 71.4% for CP and from 17.3% to 20.5% for NDF. The ED5 of OM, CP and NDF declined significantly by 4.1%, 2.5% and 2.1% units between the second and third maturity stage. Almost all investigated parameters were significantly influenced by year. Significant differences between varieties indicate that there is a potential for improvement of stover degradability through breeding. Harvest ear DM content should not exceed 55%, because nutritive value of ensiled stover declines significantly beyond this value, which could negatively affect WPMS quality in cattle feeding.