Hapten Design for Antibody-Catalyzed Decarboxylation and Ring-Opening Reactions of Benzisoxazoles

Three benzisoxazole haptens designed to elicit antibody binding sites with widely differing polarity have been synthesized and used to induce antibodies in mice. Monoclonal antibodies were prepared using hybridoma technology, and screened for catalysis of the ring-opening isomerization and/or decarboxylation of a series of related benzisoxazoles and their 3-carboxy-derivatives. No catalysis of decarboxylation was observed, but 4 of a total of 47 antibodies obtained against the three haptens catalyzed the isomerization process. Of 12 antibodies raised against the 3-acetylbenzisoxazole structure 5 none was catalytically active; but one of 24 raised against a 3-isopropenylbenzisoxazole 6 increased the rate of ring-opening of 6-nitrobenzisoxazole, and 5 of 11 antibodies raised against a benzisoxazole 7 with a 3-amidinium group were moderately active against either 6-nitro or 6-acylaminobenzisoxazoles. Competitive binding studies suggest that at least some of the antibodies induced by the isopropenyl hapten do possess a recognizably hydrophobic binding site.     

Fibrils of γ-Oryzanol + β-Sitosterol in Edible Oil Organogels

Mixtures of γ-oryzanol and β-sitosterol are able to form transparent organogels in edible oils. Small-angle X-ray scattering was used to elucidate the microstructure of the building blocks of these organogels in sunflower oil. It was found that the plant sterol(ester)s form hollow tubes with a diameter of 7.2 ± 0.1 nm. Tubes prepared with γ-oryzanol-rich structurant show the least bundle aggregation, and can be supercooled during formation most easily. The tubes melt at elevated temperatures, in agreement with the loss of structuring capacity as observed in earlier experiments.     

Effects of Quantitative Variation in Allelochemicals in <Emphasis Type="Italic">Plantago lanceolata</Emphasis> on Development of a Generalist and a Specialist Herbivore and their Endoparasitoids

Studies in crop species show that the effect of plant allelochemicals is not necessarily restricted to herbivores, but can extend to (positive as well as negative) effects on performance at higher trophic levels, including the predators and parasitoids of herbivores. We examined how quantitative variation in allelochemicals (iridoid glycosides) in ribwort plantain, Plantago lanceolata, affects the development of a specialist and a generalist herbivore and their respective specialist and generalist endoparasitoids. Plants were grown from two selection lines that differed ca. 5-fold in the concentration of leaf iridoid glycosides. Development time of the specialist herbivore, Melitaea cinxia, and its solitary endoparasitoid, Hyposoter horticola, proceeded most rapidly when reared on the high iridoid line, whereas pupal mass in M. cinxia and adult mass in H. horticola were unaffected by plant line. Cotesia melitaearum, a gregarious endoparasitoid of M. cinxia, performed equally well on hosts feeding on the two lines of P. lanceolata. In contrast, the pupal mass of the generalist herbivore, Spodoptera exigua, and the emerging adult mass of its solitary endoparasitoid, C. marginiventris, were significantly lower when reared on the high line, whereas development time was unaffected. The results are discussed with regards to (1) differences between specialist and generalist herbivores and their natural enemies to quantitative variation in plant secondary chemistry, and (2) potentially differing selection pressures on plant defense.     

Constrained tGAP for generalization between scales: The case of Dutch topographic data

This article presents the results of integrating large- and medium-scale data into a unified data structure. This structure can be used as a single non-redundant representation for the input data, which can be queried at any arbitrary scale between the source scales. The solution is based on the constrained topological Generalized Area Partition (tGAP), which stores the results of a generalization process applied to the large-scale dataset, and is controlled by the objects of the medium-scale dataset, which act as constraints on the large-scale objects. The result contains the accurate geometry of the large-scale objects enriched with the generalization knowledge of the medium-scale data, stored as references in the constraint tGAP structure. The advantage of this constrained approach over the original tGAP is the higher quality of the aggregated maps. The idea was implemented with real topographic datasets from The Netherlands for the large- (1:1000) and medium-scale (1:10,000) data. The approach is expected to be equally valid for any categorical map and for other scales as well.     

Crystal packing of a homologous series β′-stable triacylglycerols

From a homologous series of C _nC_n+2C_n (n = even) triacylglycerols which are β′-stable, Guinier X-ray powder diffraction photographs were used to determine cell parameters and space groups. The powder diffraction patterns are consistent with a pseudo-orthorhombic unit cell with space group lc2a. Only one axis is changing as a function of chain lengthening. The experimental results were used to propose a β′-crystal packing for triacylglycerols. In contrast to earlier proposed β′-crystal structures, the acyl chains of this structure are not tilted with respect to the methyl-end group plane. Furthermore, with only one molecule in the asymmetric unit, overall orthogonal chain packing is obtained when the intramolecular acyl zigzag planes are parallel.     

Sphingosine Kinase Interacting Protein is an A‐Kinase Anchoring Protein Specific for Type I cAMP‐Dependent Protein Kinase

The compartmentalization of kinases and phosphatases plays an important role in the specificity of second‐messenger‐mediated signaling events. Localization of the cAMP‐dependent protein kinase is mediated by interaction of its regulatory subunit (PKA‐R) with the versatile family of A‐kinase‐anchoring proteins (AKAPs). Most AKAPs bind avidly to PKA‐RII, while some have dual specificity for both PKA‐RI and PKA‐RII; however, no mammalian PKA‐RI‐specific AKAPs have thus far been assigned. This has mainly been attributed to the observation that PKA‐RI is more cytosolic than the more heavily compartmentalized PKA‐RII. Chemical proteomics screens of the cAMP interactome in mammalian heart tissue recently identified sphingosine kinase type 1‐interacting protein (SKIP, SPHKAP) as a putative novel AKAP. Biochemical characterization now shows that SPHKAP can be considered as the first mammalian AKAP that preferentially binds to PKA‐RIα. Recombinant human SPHKAP functions as an RI‐specific AKAP that utilizes the characteristic AKAP amphipathic helix for interaction. Further chemical proteomic screening utilizing differential binding characteristics of specific cAMP resins confirms SPHKAPs endogenous specificity for PKA‐RI directly in mammalian heart and spleen tissue. Immunolocalization studies revealed that recombinant SPHKAP is expressed in the cytoplasm, where PKA‐RIα also mainly resides. Alignment of SPHKAPs' amphipathic helix with peptide models of PKA‐RI‐ or PKA‐RII‐specific anchoring domains shows that it has largely only PKA‐RIα characteristics. Being the first mammalian PKA‐RI‐specific AKAP with cytosolic localization, SPHKAP is a very promising model for studying the function of the less explored cytosolic PKA‐RI signaling nodes.     

Reliability and effectiveness of clickthrough data for automatic image annotation

Automatic image annotation using supervised learning is performed by concept classifiers trained on labelled example images. This work proposes the use of clickthrough data collected from search logs as a source for the automatic generation of concept training data, thus avoiding the expensive manual annotation effort. We investigate and evaluate this approach using a collection of 97,628 photographic images. The results indicate that the contribution of search log based training data is positive despite their inherent noise; in particular, the combination of manual and automatically generated training data outperforms the use of manual data alone. It is therefore possible to use clickthrough data to perform large-scale image annotation with little manual annotation effort or, depending on performance, using only the automatically generated training data. An extensive presentation of the experimental results and the accompanying data can be accessed at .