BSE infectivity in jejunum, ileum and ileocaecal junction of incubating cattle

ABSTRACT: To establish bovine spongiform encephalopathy (BSE) public health protection measures it is important to precisely define the cattle tissues considered as specified risk materials (SRM). To date, in pre-clinical BSE infected cattle, no evidence of the BSE agent had been found in the gut outside of the ileal Peyer's Patches. This study was undertaken to determine when and where the pathological prion protein (PrPSc) and/or BSE infectivity can be found in the small intestine of cattle 4 to 6 months of age, orally challenged with BSE. Samples of the jejunum, the ileum and the ileocaecal junction from 46 BSE infected cattle, culled from 1 up to 44 months post infection (mpi) were examined by immunohistochemistry. Samples from cattle 8 mpi to 20 mpi were additionally studied by PTA Western blot, rapid tests, and by mouse (TgbovXV) bioassay. In doing so nearly all of the cattle, from 4 up to 44 mpi, had detectable amounts of PrPSc and/or infectivity in the distal ileum. In the distal ileum clear time-dependent variations were visible concerning the amount of PrPSc, the tissue structures affected, and the cells involved. BSE infectivity was found not only in the ileum and ileocaecal junction but also in the jejunum. The systematic approach of this study provides new data for qualitative and quantitative risk assessments and allows defining bovine SRM more precisely.     

Simultaneous determination and differentiation of glycidyl esters and 3-monochloropropane-1,2-diol (MCPD) esters in different foodstuffs by GC-MS

The aim of this study was the development of a method for the simultaneous determination and differentiation of fatty acid esters of 3-monochloropropane-1,2-diol (3-MCPD esters) and glycidol (glycidyl esters) in different foodstuffs. The esters were isolated from fat-rich food samples using a single extraction step and separated from interfering substances. For differentiation of 3-MCPD esters and glycidyl esters the glycidol moiety was converted into 3-methoxypropane-1,2-diol (3-MPD) by acidic alcoholysis. Subsequent determination was achieved by isotope dilution GC-MS after transesterification using an isotope-labeled 3-MCPD ester as internal standard. During optimization of the procedure, critical parameters affecting simultaneous determination and differentiation of these analytes were investigated. Rapid ester cleavage and derivatization at ambient temperature proved to be essential for the simultaneous determination of these analytes. The method was validated for various fat-rich foodstuffs such as bakery products, sweets, gravy, and soup powders as well as edible fats and oils. LODs of 8 and 15 μg/kg (fat-rich foodstuffs) as well as 50 and 65 μg/kg (edible oils and fats) were obtained for 3-MCPD esters and glycidyl esters, respectively. Recoveries for 3-MCPD esters and glycidyl esters ranged within 98 ± 4 and 88 ± 2% in all tested foodstuffs (0.05-2.5 mg/kg) and within 99 ± 16 and 93 ± 13% for edible oils and fats (0.15-3 mg/kg) over a wide concentration range. These results proved an accurate and differentiated determination of 3-MCPD esters and glycidyl esters with successful application to the fast screening of samples, avoiding tedious and laborious sample preparation.     

Serosurvey for selected viral agents in white rhinoceros (Ceratotherium simum) in Kruger National Park, 2007

One hundred serum samples collected from free-ranging white rhinoceros (Ceratotherium simum) in Kruger National Park (KNP) during the 2007 capture season were selected for measurement of antibody levels to several different vector-borne viral agents. These infectious diseases were chosen to compare with an earlier serosurvey that had been conducted in KNP in rhinos during 1987-1997. Positive antibody titers were found against epizootic hemorrhagic disease (EHD) of deer (8%), Bluetongue (BT) (1%), and Rift Valley fever (RVF) (49%). However, none of the 100 animals tested had detected antibody levels to African horse sickness (AHS). These values were in sharp contrast to those measured in the 1987-1997 survey in KNP white rhinos (AHS 60%, EHD 30%, BT 37%, RVF 0%). Vector-borne viral infection prevalence in white rhinos in the same geographical location appears to vary over time and may be important for monitoring presence of pathogens in an ecosystem.     

Automatic adjustment of harrowing intensity in cereals using digital image analysis

Precision farming technologies were implemented into a commercial harrow to increase selectivity of weed harrowing in spring cereals. Digital cameras were mounted before and after the harrow measuring crop cover. Crop soil cover (CSC) was computed out of these two images. Eight field experiments were carried out in spring cereals. Mode of harrowing intensity was changed in four experiments by speed, number of passes and tine angle. Each mode was varied in five intensities. In four experiments, only intensity of harrowing was changed. Weed control efficacy (WCE) and CSC were measured immediately after harrowing. Crop recovery was assessed 14 days after harrowing. Modes of intensity were not significantly different. However, intensity had significant effects on WCE and CSC. Cereals recovered from 10% CSC, and selectivity was in the constant range at 10% CSC. Therefore, 10% CSC was the threshold for the decision algorithm. If the actual CSC was below 10% CSC, intensity was increased. If the actual CSC was higher than 10%, intensity was decreased. Image analysis, decision support system and automatic control of harrowing intensity by hydraulic adjustment of tine angle were installed on a controller mounted on the harrow. The new system was tested in an additional field study. Threshold values for CSC were set at 10%, 30% and 60%. Automatic tine angle adjustment precisely realised the three different CSC values with variations of 1.5% to 3%. This development contributes to selective weed control and supports farmers during harrowing.     

Utility of Metabolomics toward Assessing the Metabolic Basis of Quality Traits in Apple Fruit with an Emphasis on Antioxidants

A gas chromatography-mass spectrometry approach was employed to evaluate the use of metabolite patterns to differentiate fruit from six commercially grown apple cultivars harvested in 2008. Principal component analysis (PCA) of apple fruit peel and flesh data indicated that individual cultivar replicates clustered together and were separated from all other cultivar samples. An independent metabolomics investigation with fruit harvested in 2003 confirmed the separate clustering of fruit from different cultivars. Further evidence for cultivar separation was obtained using a hierarchical clustering analysis. An evaluation of PCA component loadings revealed specific metabolite classes that contributed the most to each principal component, whereas a correlation analysis demonstrated that specific metabolites correlate directly with quality traits such as antioxidant activity, total phenolics, and total anthocyanins, which are important parameters in the selection of breeding germplasm. These data sets lay the foundation for elucidating the metabolic basis of commercially important fruit quality traits.     

Physical properties of a Luvisol for different long‐term fertilization treatments: II. Microscale behavior and its relation to the mesoscale

We determined the impact of different fertilization, namely organic vs. mineral fertilization, on the mesoscale parameter cyclic compressibility as well as on rheology of soil samples as a microscale parameter and how these parameters are related. Therefore, undisturbed samples were taken from a long‐term fertilization trial at the Dikop farm near Bonn (Germany) and tested for their mechanical and hydraulic properties. This paper examines the sensitivity of the soil towards cyclic loading (mesoscale) and oscillatory shearing at the microscale by means of an amplitude sweep test and the resulting parameter maximum shear stress. Fertilization increased cyclic compressibility and thus revealed structural weakness of fertilized soil samples, so did shear stress at the microscale. The main reason for this was a decrease in bulk density in the wake of fertilization. However, within the range of fertilized soil samples, the soil structure became less susceptible towards cyclic loading and oscillatory shearing, respectively, the more organic matter the soil contained (equivalent to the fertilization level). This was assumedly caused by enhanced cementation due to organic substances that could partly substitute the direct grain–grain contacts generally contributing to soil strength. The similar behavior of cyclic compressibility and maximum shear stress enabled a first approach to relate soil mechanical parameters at the microscale to those at the mesoscale.     

Application of ultrasound to disperse soil aggregates of high mechanical stability

Questions remain about the exact ultrasonic energy level that is required to effectively disperse soil aggregates and to what extent this is accompanied by physical damage to individual soil particles. We found maximum aggregate dispersion at energy levels of 1500 J cm^–3 and no evidence for the disintegration of particles < 20 μm even at that energy level. Our findings suggest that sonication at energies much greater than those applied conventionally can disperse aggregates of high mechanical stability.     

MAGNETIC RESONANCE IMAGING FEATURES OF SINONASAL DISORDERS IN HORSES

Diseases of paranasal sinuses and nasal passages in horses can be a diagnostic challenge because of the complex anatomy of the head and limitations of many diagnostic modalities. Our hypothesis was that magnetic resonance (MR) imaging would provide excellent anatomical detail and soft tissue resolution, and would be accurate in the diagnosis of diseases of the paranasal sinuses and nasal passages in horses. Fourteen horses were imaged. Inclusion criteria were lesions located to the sinuses or nasal passages that underwent MR imaging and subsequent surgical intervention and/or histopathologic examination. A low field, 0.3 tesla open magnet was used. Sequences in the standard protocol were fast spin echo T2 sagittal and transverse, spin echo T1 transverse, short‐tau inversion recovery (STIR) dorsal, gradient echo 3D T1 MPR dorsal (plain and contrast enhanced), spin echo T1 fatsat (contrast enhanced). Mean scan time to complete the examination was 53 min (range 39–99 min). Lesions identified were primary or secondary sinusitis (six horses), paranasal sinus cyst (four horses), progressive ethmoid hematoma (two horses), and neoplasia (two horses). The most useful sequences were fast spin echo T2 transverse and sagittal, STIR dorsal and FE3D MPR (survey and contrast enhanced). Fluid accumulation, mucosal thickening, presence of encapsulated contents, bone deformation, and thickening were common findings observed in MR imaging. In selected horses, magnetic resonance imaging is a useful tool in diagnosing lesions of the paranasal sinuses and nasal passages.     

Complementary studies detecting classical bovine spongiform encephalopathy infectivity in jejunum,ileum and ileocaecal junction in incubating cattle

Recently we have described the distribution of bovine spongiform encephalopathy (BSE) infectivity and/or PrP^Sc in Peyer’s patches (PP) of the small intestine of orally BSE infected cattle. In this follow-up study additional jejunal and ileal PP’s and ileocaecal-junction tissue samples from 1, 4, and 24 months post infection (mpi) were examined by mouse (Tgbov XV) bioassay. Infectivity was demonstrated in ileal PP’s 4 mpi and the distribution/extent of infectivity at 24 mpi was comparable to those seen at earlier time points, revealing no indication for a decline/clearance. These data are relevant for the definition of Specified Risk Materials in the context of the TSE legislation worldwide.     

Drones for butterfly conservation: larval habitat assessment with an unmanned aerial vehicle

Context

Evidence-based nature conservation focuses on ecological facts and the incorporation of knowledge on the ecology of species, including its entire life cycle. In butterflies, imagos and its larvae often demand specific and diverging micro-habitat structures and resources. In consequence, ecological requirements of the imaginal and pre-imaginal stage have to be taken into consideration to conduct effective conservation management.

Objective

Here we analyse ecological pre-requisites of imagos and larvae for two lycaenid butterfly species, the common blue Polyommatus icarus and the adonis blue Polyommatus bellargus. Both butterfly species occur in calcareous grasslands and mainly depend on two plant species at our study site, the horseshoe vetch Hippocrepis comosa and bird’s-foot trefoil Lotus corniculatus. These plant species serve as nectar sources and larval host plants for the two butterfly species.

Methods

First, we assessed the occurrence of imagines and larvae of the two butterfly species and recorded various micro-habitat characteristics, like the number of flower buds of the two main host plants, the surrounding vegetation height, percentage of bare soil, availability of shadow, and the distance to and geographic direction of thickets at respective sites. In a second step we took high resolution aerial pictures from our study area using an unmanned aerial vehicle (drone). Based on these aerial pictures and the information on the larvae´s habitat preference from our field observations, we trained a habitat suitability model to identify micro-habitat structures suitable for larvae of the two butterfly species.

Results

We found that abundance of imagos is positively correlated with flower bud density of the two host plants. Low vegetation height and high proportion of bare soil (but not flower bud density) positively influence egg oviposition. The calculated habitat suitability models predict the occurrence of high quality larval habitats with high prediction power (AUC = 0.72).

Conclusions

This combined data set consisting of field observations, high resolution aerial pictures taken from an unmanned aerial vehicle, and models underline that (1) species with complex life cycles may request more than one habitat niche, depending its stage of development, and (2) high resolution aerial pictures taken from drones provide valuable background data to generate habitat suitability models—even on a micro scale but covering larger parts of a landscape.