Advances in characterization of soil clay mineralogy using X‐ray diffraction: from decomposition to profile fitting

Structural characterization of soil clay minerals often remains limited despite their key influence on soil properties. In soils, complex clay parageneses result from the coexistence of clay species with contrasting particle sizes and crystal chemistry and from the profusion of mixed layers with variable compositions. The present study aimed to characterize the mineralogy and crystal chemistry of the <2 μm fraction along a profile typical of soils from Western Europe and North America (Neo Luvisol). X‐ray diffraction (XRD) patterns were interpreted using: (i) the combination of XRD pattern decomposition and indirect identification from peak positions commonly applied in soil science; and (ii) the multi‐specimen method. This latter approach implies direct XRD profile fitting and has recently led to significant improvements in the structural characterization of clay minerals in diagenetic and hydrothermal environments. In contrast to the usual approach, the multi‐specimen method allowed the complete structural characterization of complex clay parageneses encountered in soils together with the quantitative analysis of their mineralogy. Throughout the profile, the clay paragenesis of the studied Neo Luvisol systematically includes discrete smectite, illite and kaolinite in addition to randomly interstratified illite‐smectite and chlorite‐smectite. Structural characteristics of the different clay minerals, including the composition of mixed layers, did not vary significantly with depth and are thus indicative of the parent material. The relative proportion of the <2 μm fraction increased with increasing depth simultaneously with smectite relative proportion. These results are consistent with the leaching process described for Luvisols in the literature.     

Fate of Cry1Ab protein in agricultural systems under slurry management of cows fed genetically modified maize (Zea mays L.) MON810: a quantitative assessment

The objective of the study was to track the fate of recombinant Cry1Ab protein in a liquid manure field trial when feeding GM maize MON810 to dairy cows. A validated ELISA was applied for quantification of Cry1Ab in the agricultural chain from GM maize plants, feed, liquid manure and soil to crops grown on manured fields. Starting with 23.7 μg of Cry1Ab g(-1) dry weight GM maize material, a rapid decline of Cry1Ab levels was observed as 2.6% and 0.9% of Cry1Ab from the GM plant were detected in feed and liquid manure, respectively. Half of this residual Cry1Ab persisted during slurry storage for 25 weeks. After application to experimental fields, final degradation of Cry1Ab to below detectable levels in soil was reported. Cry1Ab exhibited a higher rate of degradation compared to total protein in the agricultural processes. Immunoblotting revealed a degradation of the 65 kDa Cry1Ab into immunoreactive fragments of lower size in all analyzed materials.     

First morphological characterization of 'Candidatus Mycoplasma turicensis' using electron microscopy

At least three haemotropic mycoplasmas have been recognized in cats: Mycoplasma haemofelis (Mhf), 'Candidatus Mycoplasma haemominutum' (CMhm) and 'Candidatus M. turicensis' (CMt). The latter was originally identified in a Swiss pet cat with haemolytic anaemia and shown to be prevalent in domestic cats and wild felids worldwide using molecular methods. So far, there has been no confirmatory morphological evidence of the existence of CMt presumably due to low blood loads during infection while CMhm has only been characterized by light microscopy with discrepant results. This study aimed to provide for the first time electron microscopic characteristics of CMt and CMhm and to compare them to Mhf. Blood samples from cats experimentally infected with CMt, CMhm and Mhf were used to determine copy numbers in blood by real-time PCR and for transmission and scanning electron microscopy. High resolution scanning electron microscopy revealed CMt and CMhm to be discoid-shaped organisms of 0.3 μm in diameter attached to red blood cells (RBCs). In transmission electron microscopy of CMt, an oval organism of about 0.25 μm with several intracellular electron dense structures was identified close to the surface of a RBC. CMhm and CMt exhibited similar morphology to Mhf but had a smaller diameter. This is the first study to provide morphological evidence of CMt thereby confirming its status as a distinct haemoplasma species, and to present electron microscopic features of CMhm.     

Feed or food responsible for the presence of low-level thiouracil in urine of livestock and humans?

In recent years, questions have been raised on the possible semi-endogenous status of the alleged xenobiotic thyreostatic drug thiouracil; thiouracil has been detected in the urine of various animals (livestock and domesticated) at concentrations between 1 and 10 μg L(-1) and also in human urine. Although several studies suggest Brassicaceae-derived feed as potential origin, no traces of thiouracil have been detected in feed so far. Therefore, the aim of this study was to elucidate the origin of thiouracil in the urine of livestock and humans. To this purpose various Brassicaceae feed and food sources (e.g., rapeseed, rapeseed coarse meal, cabbage, cauliflower, broccoli) were investigated for the presence of thiouracil. In addition, the impact of the Brassicaceae-related β-thioglucosidase enzyme was evaluated. This myrosinase enzyme appeared to be crucial, because without its catalyzed hydrolysis no thiouracil could be detected in the various Brassicaceae-derived samples. Therefore, a sample pretreatment with incorporated enzymatic hydrolysis was developed after ensuring the quality performance of the extracted myrosinase mixture with a single-point glucose assay. Upon enzymatic hydrolysis and LC-MS(2) analysis, thiouracil was successfully detected in samples of traditional rapeseed, rapeseed-'00' variety coarse meal (values of erucic acid <2% and glucosinolates <25 μmol g(-1)), and rapeseed cake at 1.5, 1.6, and 0.4 μg kg(-1), respectively. As for the food samples, broccoli and cauliflower displayed thiouracil concentrations of 6.0 and <1.0 μg kg(-1), respectively. To the best of the authors' knowledge this study is the first to report the presence of naturally occurring thiouracil in feed and food samples. Future research should investigate the pathway of thiouracil formation and identify its possible precursors.     

Ectogenic Meromixis of Lake Hallst?ttersee, Austria Induced by Waste Water Intrusions from Salt Mining

Lake Hallstättersee is a holomictic alpine lake, which is influenced by salt mining since the middle Bronze Age. Beside the constant saline waste water load, two massive brine spills loaded the lake with additional 16,900 tons sodium chloride (??10,250 tons Cl^?) from 1977 to 1979 and 3,000 tons salt (??1,820 tons Cl^?) in 2005. The effect of waste water intrusions from salt mining on stratification of Lake Hallstättersee was analysed over a period of 40 years. Water density, dissolved oxygen and total phosphorus (TP) concentrations were measured and an exponential model was fitted to describe the wash-out of chloride from Lake Hallstättersee after the brine spills. Furthermore, the time required returning to holomixis and steady chloride content after the second brine spill was estimated. During the whole sampling period the minimum and maximum volume-weighted annual mean chloride concentrations were 23.58 mg/L in 1979 and 3.19 mg/L in 1998. However, the mixing regime of Lake Hallstättersee, as well as the chloride concentrations, varied considerably and exhibited three holomictic and three meromictic periods between 1970 and 2009. Holomictic periods were observed when the yearly density gradient was below 0.06 kg/m³, deepwater oxygen in spring above 4 mg/L and consequently declining TP concentration in the deepest water layer below 60 mg/m³, otherwise meromictic periods were observed. Our study showed that Hallstättersee was 13 years ectogenic meromictic and 27 years holomictic during the study period.     

Nitrogen yield and nitrogen fixation of winter faba beans

Introducing autumn-sown legumes into Central European farming systems could be beneficial for addressing two challenges for European agriculture, i.e., the substantial deficit of protein sources for livestock and expected changes in agroclimatic conditions. Therefore, a two-year field experiment was conucted under Pannonian climate conditions in eastern Austria to assess nitrogen (N) yield and N fixation of several winter faba bean varieties from different European countries as compared to a spring faba bean. Winter wheat was used as a reference crop for estimating atmospheric N fixation. Winter faba beans were susceptible to frost damage especially in the harder of the two winters. Winter faba bean varieties could not achieve a higher grain yield and a higher grain N yield than the spring faba bean but had a higher grain N concentration (except for one variety). Grain yield and grain N yield of faba beans were severely impaired by drought in one year (with a mean of varieties of 8.3 g N m^?2, winter wheat: 6.4 g N m^?2); in the other year, grain N yield of faba beans considerably surpassed that of winter wheat (with a mean of varieties of 21.5 g N m^?2, winter wheat: 8.8 g N m^?2). After harvest, faba beans left higher nitrate residues in the soil, especially in the subsoil, and higher amounts of N in above-ground residues compared to winter wheat. Faba beans showed high N fixation under optimum conditions (with a mean of varieties of 21.9 g N m^?2) whereas drought considerably impaired N fixation (with a mean of varieties of 6.3 g N m^?2; with no differences between autumn- and spring-sown faba beans). In conclusion, growing winter faba bean varieties in eastern Austria did not result in higher grain yield, grain N yield, and N fixation compared to growing a spring faba bean.     

CT FEATURES OF ALVEOLITIS AND SINUSITIS IN HORSES

Sinusitis is a common disorder in horses and may result from trauma, dental diseases, or space-occupying lesions. Radiography can only provide a limited amount of information. Computed tomography (CT) has been documented as an alternative imaging method. Eighteen horses (mostly Warmblood) with signs of chronic sinusitis were examined preoperatively with CT to assist in diagnosis of the underlying cause. There was a group of common CT features in horses with dental disease and sinusitis. The first molar was the most frequently affected maxillary cheek tooth. Hypoattenuation of the cementum, destruction of the enamel, and filling of the infundibular cavity with gas were the most frequent CT findings associated with caries. Gas bubbles within the bulging root area or fragmentation of the root in combination with swelling of the adjacent sinus lining were the most important CT features of dental decay. CT findings associated with sinusitis included excessive thickening of the respiratory epithelium in the rostral maxillary sinus; the caudal maxillary sinus was less often involved. The infraorbital canal, the nasomaxillary duct, and the frontomaxillary aperture were usually involved. The maxillary bone, however, especially the facial crest, was involved in nearly every horse, being characterized by endosteal sclerosis, thickening, periosteal reaction, and deformation leading to facial swelling in chronic infections. CT images allowed identification of involvement of individual teeth more clearly to reveal the diseased one for treatment. Three-dimensional imaging allowed improved understanding of the extent and severity of the pathologic change.     

Equine odontoclastic tooth resorption and hypercementosis

A poorly described, painful disorder of incisor and canine teeth, variably causing periodontitis, with resorptive or proliferative changes of the calcified dental tissues, has recently been documented in aged horses. No plausible aetiopathogenesis for this syndrome has been recorded. Eighteen diseased teeth from eight horses were examined grossly and microscopically and showed the presence of odontoclastic cells by tartrate resistant acid phosphatase (TRAP) staining. A chronological sequence of odontoclastic resorption followed by hypercementosis was demonstrated and, consequently, the term equine odontoclastic tooth resorption and hypercementosis (EOTRH) is proposed for this disorder. EOTRH shares many features with similar dental syndromes described in humans and cats. An aetiological hypothesis proposes mechanical stress of the periodontal ligament as the initiating factor.