Reliability of pelvimetry is affected by observer experience but not by breed and sex: A cross-sectional study in beef cattle

Pelvis size plays an important role to prevent dystocia in cattle caused by the foeto-maternal disproportion in commonly primiparous females. The reproducibility and repeatability are two important aspects for the reliability of the measurements to use in the selection of cattle for culling. Pelvic measures were taken with a Rice pelvimeter from 224 young cattle (180 females and 44 males) of four beef breeds in South Africa. One experienced and two inexperienced observers each measured pelvic height and width twice. The proportion measurements with a maximum difference of 0.5 cm within animal compared with the first measurement by the experienced observer are around 80% and by the inexperienced observers around 50% for pelvic height and around 60% for pelvic width. Breed and sex do not affect the reliability of pelvimetry by an experienced observer. Under- and overestimation of pelvis size were observed in inexperienced observers, which seems to be unrelated to breed and sex.     

Differentiation between lutein monoester regioisomers and detection of lutein diesters from marigold flowers (Tagetes erecta L.) and several fruits by liquid chromatography-mass spectrometry.

Liquid chromatography-atmospheric pressure chemical ionization mass spectrometry (LC-APCIMS) was employed for the identification of eight lutein monoesters, formed by incomplete enzymatic saponification of lutein diesters of marigold (Tagetes erecta L.) by Candida rugosa lipase. Additionally, the main lutein diesters naturally occurring in marigold oleoresin were chromatographically separated and identified. The LC-MS method allows for characterization of lutein diesters occurring as minor components in several fruits; this was demonstrated by analysis of extracts of cape gooseberry (Physalis peruviana L.), kiwano (Cucumis metuliferus E. Mey. ex Naud.), and pumpkin (Cucurbita pepo L.). The assignment of the regioisomers of lutein monoesters is based on the characteristic fragmentation pattern: the most intense daughter ion generally results from the loss of the substituent (fatty acid or hydroxyl group) bound to the epsilon-ionone ring, yielding an allylic cation. The limit of detection was estimated at 0.5 microg/mL with lutein dimyristate as reference compound. This method provides a useful tool to obtain further insight into the biochemical reactions leading to lutein ester formation in plants.     

Using model scenarios to predict and evaluate forest-management impacts on soil base saturation at landscape level

Silviculture, forest conversion and technical tools of ecosystem management, such as forest liming, display their effects at the landscape level. Therefore their planning and control should take place at the same scale. The primary objective of this work was to assess soil chemical properties and their changes in relationship to ecosystem management, especially forest conversion and forest liming. We calculated scenario models, based on regression analysis, which allow such an examination in the context of understanding landscape processes which can be expected to operate in the sampling region. Stepwise multiple linear regression analysis was used to predict soil chemical attributes (base saturation, pH, C/N content and stock, exchangeable stocks of Ca and Mg) as indicators of site stability or off-site effects of forest ecosystems such as effects on clean drinking water from forested watersheds. Because of space limitations, in this paper only the modelling results of base saturation are presented. Base saturation was used as an integrative example for other soil chemical properties. The transformation of measurements to the regional scale, i.e., the regionalization, was calculated for the forested parts of two test regions in the Black Forest on the basis of measured chemical properties of 90–150 soil profiles per test region. The models have a spatial resolution of 50×50 m, which is a spatial scale relevant for forestry practice and forest management. Topographic variables (e.g., elevation, aspect, slope gradient, and slope length), the stratigraphic classification of the geologic substrate, stand characteristics from forest inventory data, and finally technical information about forest liming were the auxiliary variables (secondary site properties) that provided indirect information about base saturation and were available for the whole forested area of the test regions. Base saturation could be predicted with an accuracy of ~50–70% (in terms of the multiple R²) by using these properties as predictor variables in multiple linear regression analyses. The explained proportion of variance was unexpectedly high considering the high geomorphological heterogeneity of the two test regions. Based upon the regionalization models, it was possible to establish scenarios showing the landscape-related effects on base saturation that may be achieved by forest conversion towards a higher proportion of forests with broad-leaved mixed stands and by forest liming. These scenarios allow the interactions between several influencing factors and management strategies and the impacts on the target variable to be synoptically judged. Thus the presented regionalization models achieve the role of decision support tools for the planning of forest management at the landscape level. They allow an assessment of the environmental effects of forest management strategies in terms of site sustainability or preservation of water resources in forested catchments.     

Upscaling spatio‐temporal patterns of cation fluxes in acid forest soils

One main problem with current research on spatio‐temporal modeling of ion fluxes in forest soils is the separation of space and time effects in the soil‐monitoring concept. This article describes an approach to overcome this weakness. Time trends of point information on soil‐solution data (base‐cation concentrations and fluxes) are scaled by linking them to soil‐chemical data which is available in higher spatial resolution and can be upscaled to an area base. This approach is based on a combined evaluation of bulk soil and soil‐solution data using both statistical and process‐oriented methods. Multiple‐linear‐regression analyses coupled with geostatistics were developed to predict spatial patterns of exchangeable cation percentages. In a second step, empirical ion‐distribution coefficients were adapted according to Gapon using data of suction‐cup plots and bulk‐soil samples. Seasonally adjusted time‐series data of soil‐solution chemistry were then connected with the maps of the predicted exchangeable‐cation percentages by means of the Gapon equations. This evaluation step provided both time‐ and space‐dependent maps of cation concentrations in the soil solution. Finally, using the results of a water‐budget model it was possible to derive spatio‐temporal patterns of soil cation fluxes. Methodological limitations and the results of verification processes are discussed. The methods described can only be used in acidic soils and should not be used in soil layers rich in humus, since adsorption to C compounds differs from adsorption to clay minerals. The time increments of the models should be not shorter than yearly in order to suppress annual periodicity. Although the Gapon equations were not based on laboratory‐determined exchange solutions at quasi‐equilibrium, but rather on field data from the suction‐cup technique, the exchangeable‐cation percentages showed steady functions of selectivity coefficients. The methods tested at a watershed scale may be flexible enough to be applied at other scales as well.     

Der Einfluß von Dieselkraftstoff auf die Aggregatstabilität,den Plastizitätsindex und das Scherverhalten unterschiedlicher Bodenmaterialien

The effect of Diesel fuel on stability of aggregates, plasticity index and shear strength of two soil materials The influence of Diesel fuel contamination on mechanical properties of soil are investigated with regard to the retreatment of materials after a cleaning process. Following aspects are examined in laboratory tests: waterstability of aggregates, plasticity index and shear strength parameter. The used soil materials are mixed samples of a Luvisol (=Bt) and a tidal influenced alluvial clay sediment of a Gley (=Klei). The aggregate stability of Bt material is rising at increasing Diesel fuel contaminations due to a hydrophob effect on the surfaces of the aggregates. This influence cannot be shown for clay material. On the other hand the plasticity index shows a decrease for low Diesel fuel contaminations, because the Diesel fuel acts directly to the particle surfaces. At increasing contaminations these effects are overlayed by increasing viscosity and shear strength of water and Diesel fuel phases or emulsions. The increase in stability of aggregates is not evident in a shear box test. The Diesel fuel shows no influence to angle of internal friction for both investigated materials. On the other hand there is an effect to the cohesion. This phenomenon could be explicated with above mentioned increase in cohesion due to an increase in shear strength and viscosity of a two phase system.     

Identification and quantification of astaxanthin esters in shrimp (Pandalus borealis) and in a microalga (Haematococcus pluvialis) by liquid chromatography-mass spectrometry using negative ion atmospheric pressure chemical ionization

Negative ion liquid chromatography-atmospheric pressure chemical ionization mass spectrometry [negative ion LC-(APCI)MS] was used for the identification of astaxanthin esters in extracts of commercial shrimp (Pandalus borealis) and dried microalga (Haematococcus pluvialis) samples. A cleanup step using a normal phase solid phase extraction (SPE) cartridge was applied prior to analysis. Recovery experiments with astaxanthin oleate as model compound proved the applicability of this step (98.5 +/- 7.6%; n = 4). The assignment of astaxanthin esters in negative ion LC-(APCI)MS was based on the detection of the molecular ion (M*-) and the formation of characteristic fragment ions, resulting from the loss of one or two fatty acids. Quantification of individual astaxanthin esters was performed using an astaxanthin calibration curve, which was found to be linear over the required range (1-51 micromol/L; r2 = 0.9996). Detection limits, based on the intensity of M*-, a signal-to-noise ratio of 3:1, and an injection volume of 20 microL, were estimated to be 0.05 microg/mL (free astaxanthin), 0.28 microg/mL (astaxanthin-C16:0), and 0.78 microg/mL (astaxanthin-C16:0/C16:0), respectively. This LC-(APCI)MS method allows for the first time the characterization of native astaxanthin esters in P. borealis and H. pluvialis without using time-consuming isolation steps with subsequent gas chromatographic analyses of fatty acid methyl esters. The results suggest that the pattern of astaxanthin-bound polyunsaturated fatty acids of P. borealis does not reflect the respective fatty acid pattern found in triacylglycerides. Application of the presented LC-(APCI)MS technique in common astaxanthin ester analysis will forestall erroneous xanthophyll ester assignment in natural sources.     

Carotenoids and carotenoid esters in potatoes (Solanum tuberosum L.): new insights into an ancient vegetable

The carotenoid pattern of four yellow- and four white-fleshed potato cultivars (Solanum tuberosum L.), common on the German market, was investigated using HPLC and LC(APCI)-MS for identification and quantification of carotenoids. In each case, the carotenoid pattern was dominated by violaxanthin, antheraxanthin, lutein, and zeaxanthin, which were present in different ratios, whereas neoxanthin, beta-cryptoxanthin, and beta,beta-carotene generally are only minor constituents. In contrast to literature data, antheraxanthin was found to be the only carotenoid epoxide present in native extracts. The total concentration of the four main carotenoids reached 175 microg/100 g, whereas the sum of carotenoid esters accounted for 41-131 microg/100 g. Therefore, carotenoid esters are regarded as quantitatively significant compounds in potatoes. For LC(APCI)-MS analyses of carotenoid esters, a two-stage cleanup procedure was developed, involving column chromatography on silica gel and enzymatic cleavage of residual triacylglycerides by lipases. This facilitated the direct identification of several potato carotenoid esters without previous isolation of the compounds. Although the unequivocal identification of all parent carotenoids was not possible, the cleanup procedure proved to be highly efficient for LC(APCI)-MS analyses of very low amounts of carotenoid esters.     

A food-grade system for inducible gene expression in Lactobacillus plantarum using an alanine racemase-encoding selection marker

Food-grade gene expression systems for lactic acid bacteria are useful for applications in the food industry. We describe a new food-grade host/vector system for Lactobacillus plantarum based on pSIP expression vectors and the use of the homologous alanine racemase gene (alr) as selection marker. A new series of expression vectors were constructed by exchanging the erythromycin resistance gene (erm) in pSIP vectors by the L. plantarum WCFS1 alr gene. The vectors were applied for the overexpression of β-galactosidase genes from L. reuteri L103 and L. plantarum WCFS1 in an alr deletion mutant of L. plantarum WCFS1. The expression levels obtained in this way, i.e. without the use of antibiotics, were comparable to the levels obtained with the conventional system based on selection for erythromycin resistance. The new system is suitable for the production of ingredients and additives for the food industry.     

Identification and quantification of zeaxanthin esters in plants using liquid chromatography-mass spectrometry

It has been suggested that lutein and zeaxanthin may decrease the risk for age-related macular degeneration. Surprisingly, oleoresins rich in zeaxanthin are not yet available on the market. Several authors have reported enhanced stability of esterified xanthophylls, so plants containing zeaxanthin esters were investigated to establish valuable sources for the production of durable oleoresins. Liquid chromatography-atmospheric pressure chemical ionization mass spectrometry [LC-(APCI)MS] was used to unequivocally identify zeaxanthin esters of a standard mixture and in several plant extracts. Zeaxanthin esters were quantified on the basis of their respective molecular masses using zeaxanthin for calibration; total zeaxanthin was determined after saponification of aliquots of the extracts. Thus, dried wolfberries (Lycium barbarum), Chinese lanterns (Physalis alkekengi), orange pepper (Capsicum annuum), and sea buckthorn (Hippophae rhamnoides) proved to be valuable zeaxanthin ester sources. The present LC-MS method allows for an even more detailed analysis of zeaxanthin esters than reported previously.