Intraobserver and interobserver repeatability of ocular biometric measurements obtained by means of B-mode ultrasonography in dogs

OBJECTIVE: To assess intra- and interobserver repeatability of ocular biometric measurements obtained by means of high-resolution B-mode ultrasonography in dogs. Animals-6 Beagles without ocular abnormalities. PROCEDURES: B-mode ultrasonography was performed bilaterally with a 10.5-MHz broadband compact linear array transducer. All measurements were made on 2 different occasions by 2 observers. The Bland-Altman method was used to assess agreement between measurements obtained by the 2 observers and between the 2 sets of measurements obtained by each observer. RESULTS: Intra- and interobserver repeatability was highest for larger measurements, such as depth of the eye and depth of the anterior chamber. When repeatability was examined, bias was significantly different from 0 for only a few measurements, but the percentage difference between observations was as high as 180% for some measurements. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that most measurements of intraocular distances and structures obtained by means of high-resolution B-mode ultrasonography have acceptable intra- and interobserver repeatability. However, the percentage difference between observations can be high for smaller measurements.     

Inheritance of rol-genes from Agrobacterium rhizogenes through two generations in Kalancho?

Transformation of Kalancho? blossfeldiana ‘Molly’ using the naturally occurring bacterium Agrobacterium rhizogenes is a non-GMO strategy to breed compact plants. In the present study, crosses resembling a commercial breeding strategy were made to determine if the improved ornamental quality observed in the T1 generation was inherited to the offspring. F1 lines were produced by crossing the commercial Kalancho? cultivar ‘Sarah’ with a selected T1 line. Subsequently, F2 populations were produced by self-pollination of individual selected lines. The rol-genes were inherited to the progeny and the presence of rol-genes was confirmed in all F1 and many F2 plant lines exhibiting dwarfism. Screening of F1 and F2 plants showed that the rol-genes were inherited together. Besides decreased plant height, several F1 and F2 lines containing rol-genes exhibited changes in plant diameter, number of branches, flower diameter and time to first open flower and duration of flowering compared to the WT ‘Molly’. Furthermore, increased ethylene tolerance was observed in several lines containing rol-genes compared to the WT ‘Sarah’. Screening of three selected F2 populations derived from self-pollination of F1 lines containing rol-genes indicated a shift in distribution towards a lower mean plant height within the entire plant population compared to a control population of plants without rol-genes. Moreover, one of these F2 populations also exhibited earlier flowering compared to the control population. Compact potted plants and lines without delayed flowering and with improved ethylene tolerance were obtained and are valuable in commercial breeding programmes without using recombinant DNA technology.     

Water-mediated proton hopping on an iron oxide surface

The diffusion of hydrogen atoms across solid oxide surfaces is often assumed to be accelerated by the presence of water molecules. Here we present a high-resolution, high-speed scanning tunneling microscopy (STM) study of the diffusion of H atoms on an FeO thin film. STM movies directly reveal a water-mediated hydrogen diffusion mechanism on the oxide surface at temperatures between 100 and 300 kelvin. Density functional theory calculations and isotope-exchange experiments confirm the STM observations, and a proton-transfer mechanism that proceeds via an H(3)O(+)-like transition state is revealed. This mechanism differs from that observed previously for rutile TiO(2)(110), where water dissociation is a key step in proton diffusion.     

Development and characterization of mouse monoclonal antibodies reactive with chicken CD83

This study was carried out to develop and characterize mouse monoclonal antibodies (mAbs) against chicken CD83 (chCD83), a membrane-bound glycoprotein belonging to the immunoglobulin superfamily that is primarily expressed on mature dendritic cells (DCs). A recombinant chCD83/IgG4 fusion protein containing the extracellular region of chCD83 was expressed in Chinese Hamster Ovary (CHO) cells and isolated from the spent cell culture medium by protein G affinity chromatography. The extracellular region of the chCD83 protein was purified and used to immunize mice. A cell fusion was performed, from which 342 hybridomas were screened for mAbs to chCD83. Two mAbs, chCD83-159 and chCD83-227, stained the greatest percentage of chCD83-transfected CHO cells and were selected for further characterization. By flow cytometry, both mAbs reacted with a chicken macrophage cell line, HD11. Both mAbs also recognized a single 53 kDa protein on Western blots of lysates from lipopolysaccharide-stimulated spleen mononuclear cells or unstimulated HD11 cells. Immunostaining of chicken secondary lymphoid organs identified chCD83(+) cells with morphologic and subtissue localization properties comparable to mammalian DCs. In vitro stimulation of spleen mononuclear cells with concanavalin A (Con A) decreased the percentage of chCD83(+) cells compared with cells treated with medium alone. Interestingly, spleen cells treated with Con A in the presence of chCD83-227 mAb exhibited decreased percentage of MHCII(+) cells compared with cells treated with an isotype-matched negative control mAb. These chCD83 mAbs may be useful for future investigations of chicken immune cell maturation and mechanisms of action.     

The landscape matrix modifies the effect of habitat fragmentation in grassland butterflies

The landscape matrix is suggested to influence the effect of habitat fragmentation on species richness, but the generality of this prediction has not been tested. Here, we used data from 10 independent studies on butterfly species richness, where the matrix surrounding grassland patches was dominated by either forest or arable land to test if matrix land use influenced the response of species richness to patch area and connectivity. To account for the possibility that some of the observed species use the matrix as their main or complementary habitat, we analysed the effects on total species richness and on the richness of grassland specialist and non-specialist (generalists and specialists on other habitat types) butterflies separately. Specialists and non-specialists were defined separately for each dataset. Total species richness and the richness of grassland specialist butterflies were positively related to patch area and forest cover in the matrix, and negatively to patch isolation. The strength of the species-area relationship was modified by matrix land use and had a slope that decreased with increasing forest cover in the matrix. Potential mechanisms for the weaker effect of grassland fragmentation in forest-dominated landscapes are (1) that the forest matrix is more heterogeneous and contains more resources, (2) that small grassland patches in a matrix dominated by arable land suffer more from negative edge effects or (3) that the arable matrix constitutes a stronger barrier to dispersal between populations. Regardless of the mechanisms, our results show that there are general effects of matrix land use across landscapes and regions, and that landscape management that increases matrix quality can be a complement to habitat restoration and re-creation in fragmented landscapes.     

Public purchases and private preferences: Challenges for analyzing public open space acquisitions

The traditional hedonic model uses market purchases to estimate implicit prices. Hedonic models composed of only public land purchases violate key assumptions of hedonic model theory. The resulting implicit prices cannot be interpreted as the purchasing agency's maximum willingness to pay. The problems are illustrated using a hedonic model of public land purchases in the Town of Brookhaven, on Long Island, New York, USA. The model reveals negative elasticities for attributes for which the agency has stated positive preferences. For example, the presence of unique glacial landforms (a positive attribute) was associated with a 97% increase in property cost. However, if purchasing the open space property prevented development that is incompatible with existing land uses (also a positive attribute), the property cost decreased by 69%. The results confirm that elasticities and implicit prices derived from open space “public hedonic models” should be interpreted in the context of the broader market for land, not as the agency's willingness to pay. The work has implications for open space preservation policies in urbanizing regions.     

REVIEW: Rye Arabinoxylans: Molecular Structure,Physicochemical Properties and Physiological Effects in the Gastrointestinal Tract

Arabinoxylans (AX) are the main dietary fiber (DF) polysaccharides in rye where they represent ≈55% of the total polysaccharides. Rye AX consist of a backbone of (1→4)‐β‐d ‐xylopyranosyl residues (X) mainly substituted with α‐l ‐arabinofuranosyl residues (A) to varying degrees at the O‐2 position, the O‐3 position, or both. The A/X ratio of total AX is 0.49–0.82 and extractable AX ratio is 0.34–0.85 in different studies. AX also contain small amounts of ferulate residues bound to arabinose as esters at its O‐5 position. The weight average molecular weight varies from 40,000 to 900,000 with an average of ≈200,000. AX influence physiology in different segments of the gastrointestinal tract. The complex molecular structure of rye AX makes them resistant against microbial modification in the small intestine; consequently, rye AX have a much higher influence on the viscosity in the small intestinal digesta than does β‐glucan from oats and barley. In spite of that, it has not been possible in studies with AX‐rich foods such as bread to demonstrate a significant effect on the postprandial glucose response, however, a significantly reduced insulin response has been seen. Nevertheless, addition of 6 g and 12 g of AX‐rich wheat fiber to a breakfast meal has significantly lowered postprandial glucose and insulin response. Studies with hypercholesterolemic pigs fed rye buns rich in AX have resulted in dramatic reductions in plasma total and LDL cholesterol, whereas a gender difference was seen in studies on the effect of AX on plasma lipids in humans. Only certain species of bacteria from the human gut produce the enzymes needed for the degradation of AX. Nevertheless, wheat AX stimulate prebiotic bacteria presumably brought about by cross feeding of lactobacilli and bifidobacteria with degradation products from versatile carbohydrate‐degrading bacteria. Soluble AX are readily fermented in the large intestine, the majority is broken down between the ileum and the cecum. AX, characterized by a low degree of substitution and virtually no doubly substituted xylose, are slowly degraded at more distal locations. The remaining AX, characterized by a high degree of substitution, are not degraded at all. Although the fermentation pattern of AX may vary in different experimental models, in vitro fermentation studies and in vivo intervention studies with animals and humans point to AX as substrates that enhance the formation of butyrate in the large intestine.     

Root-released organic acids and phosphorus uptake of two barley cultivars in laboratory and field experiments

A major portion of phosphorus (P) applied as fertilizers is bound in soils as P compounds of variable adsorption strength, reducing the effectiveness of P fertilization. Plant genotypes equipped with mechanisms for utilizing the adsorbed P more efficiently can, therefore, enhance the effectiveness of P fertilization. Such genotypes will also enrich plant gene pools for further analysis and upgrading of P efficiency by selection and breeding. We studied the variation and the mechanisms of P uptake of two winter barley (Hordeum vulgare L.) cultivars Marinka and Sonate (parents of existing 200 haploid progeny lines), by laboratory and field experiments. After cultivation in nutrient solution for 21 days, Marinka produced more roots than Sonate, but similar amounts of dry shoots of lower P content (Marinka 3.4±0.4 mg g⁻¹, Sonate 4.9±0.6 mg g⁻¹). The total P uptake per plant did not differ between the cultivars. Marinka retained more P in roots as indicated by the higher concentration of P in the roots (Marinka 3.9±0.3 mg g⁻¹ and Sonate 3.0±0.4 mg g⁻¹). In sterile nutrient solution culture, the cultivars differed mainly in release of organic acids from the roots, with Marinka releasing three times more citric acid and nearly two times more acetic acid than Sonate. The cultivars had similar root hair lengths and they did not differ (P>0.05) in depletion of available soil P fraction (extracted with 0.5 M NaHCO₃) in the rhizosphere. Marinka absorbed nearly twice as much P from the strongly adsorbed soil P fraction (extracted with 0.1M NaOH). Also under field conditions, Marinka absorbed more P and produced more shoot dry matter. The higher P uptake by Marinka than Sonate can be attributed to its ability to acquire P from strongly adsorbed soil P by releasing more organic acids, especially citric acid, from its roots.