Do Implicit Attitudes Predict Actual Voting Behavior Particularly for Undecided Voters?

The prediction of voting behavior of undecided voters poses a challenge to psychologists and pollsters. Recently, researchers argued that implicit attitudes would predict voting behavior particularly for undecided voters whereas explicit attitudes would predict voting behavior particularly for decided voters. We tested this assumption in two studies in two countries with distinct political systems in the context of real political elections. Results revealed that (a) explicit attitudes predicted voting behavior better than implicit attitudes for both decided and undecided voters, and (b) implicit attitudes predicted voting behavior better for decided than undecided voters. We propose that greater elaboration of attitudes produces stronger convergence between implicit and explicit attitudes resulting in better predictive validity of both, and less incremental validity of implicit over explicit attitudes for the prediction of voting behavior. However, greater incremental predictive validity of implicit over explicit attitudes may be associated with less elaboration.     

Hodgkin’s lymphoma RNA-transfected dendritic cells induce cancer/testis antigen-specific immune responses

Cytotoxic T lymphocytes (CTL) can kill Hodgkin's lymphoma (HL) cells, and CTL have been used for the treatment of Epstein-Barr virus (EBV)-positive HL. For patients with EBV-negative HL, this strategy cannot be employed and alternative target structures have to be defined. In order to establish a system for the stimulation of HL-reactive T cells, we used dendritic cells (DC) as antigen-presenting cells for autologous T cells and transfected these DC with RNA from established HL cell lines. After stimulation of peripheral blood mononuclear cells (PBMC) with RNA-transfected DC, we analyzed the reactivity of primed PBMC by interferon gamma enzyme-linked immunospot. Our results suggest the presence of antigens with expression in HL cell lines and recognition of these antigens in combination with DC-derived human leukocyte antigen molecules. By the analysis of Gene Expression Omnibus microarray data sets from HL cell lines and primary HL samples in comparison with testis and other normal tissues, we identified HL-associated cancer testis antigens (CTA) including the preferentially expressed antigen in melanoma (PRAME). After stimulation of PBMC with RNA-transfected DC, we detected PRAME-reactive T cells. PRAME and other HL-associated CTA might be targets for HL-specific immune therapy or for the monitoring of HL-directed immune responses.     

Locally resolved membrane binding affinity of the N-terminus of α-synuclein

α-Synuclein is abundantly present in Lewy bodies, characteristic of Parkinson's disease. Its exact physiological role has yet to be determined, but mitochondrial membrane binding is suspected to be a key aspect of its function. Electron paramagnetic resonance spectroscopy in combination with site-directed spin labeling allowed for a locally resolved analysis of the protein-membrane binding affinity for artificial phospholipid membranes, supported by a study of binding to isolated mitochondria. The data reveal that the binding affinity of the N-terminus is nonuniform.     

Knock-down of Pdcd4 stimulates angiogenesis via up-regulation of angiopoietin-2

The tumor suppressor Pdcd4 is involved in multiple pathways. Considering its biological action conflicting data in the literature exist and, consequently, our own studies point to a cell type specific action of Pdcd4. In the present study, using several Pdcd4 knock down cell lines we succeeded to identify angiopoietin-2 (Ang-2) as a gene up-regulated on the mRNA and protein level. The subsequent enhanced peptide secretion forced wild type Bon-1 cells in a neoplastic direction demonstrated by increased proliferation and colony formation while cell adhesion was decreased. Most likely, the stimulation of Ang-2 is in part mediated by increased activation of AP-1 but different signal transduction pathways may also be involved since we found opposite activation of PI3K/Akt/mTOR and MAPK7ERK pathways (both known to regulate in Ang-2 expression). Ang-2 is a modulator of vascular remodeling. Therefore, we analyzed the effect of supernatants from Pdcd4 knock-down cell lines on endothelial cells. Again, we detected reduced cell adhesion and increased colony formation. Probably, the most impressive effect was described on tube formation in a model for angiogenesis. Tube length and junctions of endothelial cells treated with conditioned medium from Pdcd4 knock-down cells were considerably increased. Both, up-regulation of Ang-2 and down-regulation of Pdcd4 are described for many tumors. However, this is the first study showing a direct impact of Pdcd4 on Ang-2 levels and, thereby, angiogenesis. Our data suggest a completely new mechanism for Pdcd4 to act as a tumor suppressor rendering Pdcd4 an attractive target for new therapeutic strategies in cancer treatment.     

Homeotic Arm-to-Leg Transformation Associated with Genomic Rearrangements at the PITX1 Locus

The study of homeotic-transformation mutants in model organisms such as Drosophila revolutionized the field of developmental biology, but how these mutants relate to human developmental defects remains to be elucidated. Here, we show that Liebenberg syndrome, an autosomal-dominant upper-limb malformation, shows features of a homeotic limb transformation in which the arms have acquired morphological characteristics of a leg. Using high-resolution array comparative genomic hybridization and paired-end whole-genome sequencing, we identified two deletions and a translocation 5′ of PITX1. The structural changes are likely to remove active PITX1 forelimb suppressor and/or insulator elements and thereby move active enhancer elements in the vicinity of the PITX1 regulatory landscape. We generated transgenic mice in which PITX1 was misexpressed under the control of a nearby enhancer and were able to recapitulate the Liebenberg phenotype.     

Immunoassay-based proteome profiling of 24 pancreatic cancer cell lines

Pancreatic ductal adenocarcinoma is one of the most deadly forms of cancers, with a mortality that is almost identical to incidence. The inability to predict, detect or diagnose the disease early and its resistance to all current treatment modalities but surgery are the prime challenges to changing the devastating prognosis. Also, relatively little is known about pancreatic carcinogenesis. In order to better understand relevant aspects of pathophysiology, differentiation, and transformation, we analysed the cellular proteomes of 24 pancreatic cancer cell lines and two controls using an antibody microarray that targets 741 cancer-related proteins. In this analysis, 72 distinct disease marker proteins were identified that had not been described before. Additionally, categorizing cancer cells in accordance to their original location (primary tumour, liver metastases, or ascites) was made possible. A comparison of the cells' degree of differentiation (well, moderately, or poorly differentiated) resulted in unique marker sets of high relevance. Last, 187 proteins were differentially expressed in primary versus metastatic cancer cells, of which the majority is functionally related to cellular movement.     

Phylogeny of the Trilobite Subgenus Acanthopyge (Lobopyge)

Cladistic analysis of the trilobite subgenus Acanthopyge (Lobopyge) has not been previously attempted, apart from an inferred phylogeny of the Lichida by Thomas and Holloway (1988, Philos. Trans. R. Soc. London B Biol. Sci. 321, 179–262). Results of two separate analyses with variable taxonomic sampling show a possible cosmopolitan affinity for Australian Devonian species of A. (Lobopyge) and corroborate the placement of A. (Lobopyge) rohri in A. (Lobopyge) . Benelopyge is a junior subjective synonym of A. (Lobopyge) .     

Neph-Nephrin proteins bind the Par3-Par6-atypical protein kinase C (aPKC) complex to regulate podocyte cell polarity

The kidney filter represents a unique assembly of podocyte epithelial cells that tightly enwrap the glomerular capillaries with their foot processes and the interposed slit diaphragm. So far, very little is known about the guidance cues and polarity signals required to regulate proper development and maintenance of the glomerular filtration barrier. We now identify Par3, Par6, and atypical protein kinase C (aPKC) polarity proteins as novel Neph1-Nephrin-associated proteins. The interaction was mediated through the PDZ domain of Par3 and conserved carboxyl terminal residues in Neph1 and Nephrin. Par3, Par6, and aPKC localized to the slit diaphragm as shown in immunofluorescence and immunoelectron microscopy. Consistent with a critical role for aPKC activity in podocytes, inhibition of glomerular aPKC activity with a pseudosubstrate inhibitor resulted in a loss of regular podocyte foot process architecture. These data provide an important link between cell recognition mediated through the Neph1-Nephrin complex and Par-dependent polarity signaling and suggest that this molecular interaction is essential for establishing the three-dimensional architecture of podocytes at the kidney filtration barrier.     

Elastase Digests: New Ammunition for Shotgun Membrane Proteomics

Despite many advances in membrane proteomics during the last decade the fundamental problem of accessing the transmembrane regions itself has only been addressed to some extent. The present study establishes a method for the nano-LC-based analysis of complex membrane proteomes on the basis of a methanolic porcine pancreatic elastase digest to increase transmembrane coverage. Halobacterium salinarium purple and Corynebacterium glutamicum membranes were successfully analyzed by using the new protocol. We demonstrated that elastase digests yield a large proportion of transmembrane peptides, facilitating membrane protein identification. The potential for characterization of a membrane protein through full sequence coverage using elastase is there but is restricted to the higher abundance protein components. Compatibility of the work flow with the two most common mass spectrometric ionization techniques, ESI and MALDI, was shown. Currently better results are obtained using ESI mainly because of the low response of MALDI for strictly neutral peptides. New findings concerning elastase specificity in complex protein mixtures reveal a new prospect beyond the application in shotgun experiments. Furthermore peptide mass fingerprinting with less specific enzymes might be done in the near future but requires an adaptation of current search algorithms to the new proteases.Upon the introduction of modern mass spectrometric ionization techniques, such as MALDI (1) and ESI (2), extremely powerful and valuable tools were given to researchers for the identification and characterization of proteins. Nevertheless the intricate analysis of membrane subproteomes still represents one of the major challenges despite the amount of “success” reported in the literature. Until now, there was no general protocol available to address membrane proteomes as a whole, demonstrating their degree of difficulty and complexity.During the past years, two different strategies in proteome analysis have evolved: the more widespread bottom-up and top-down proteomics. The latter approach has been shown to provide access to the transmembranal regions of membrane proteins and has the power to characterize complete protein primary structures including labile covalent modifications (3, 4). Nevertheless there are limitations due to sample complexity, emphasizing the need for a liquid chromatographic separation on the protein level, which is comparable to LC peptide separation. Therefore, the bottom-up variant is the most commonly used method for the proteomics analysis of complex membrane samples. Improvements in the bottom-up work flow were achieved by adapting sample cleanup and prefractionation processes (5–10) and subsequently by the development of modified and optimized separation techniques. The two main work flows, the gel-based approach mainly carried out with 2D¹ SDS-PAGE (11, 12) and the shotgun identification of proteolytically digested protein mixtures and their multidimensional separation via liquid chromatography (13), had to be adapted. The separation of proteins via classical 2D SDS-PAGE is only possible up to a GRAVY score of ∼0.4 (14, 15). Despite lacking the separation power of the IEF-SDS-PAGE system, derived techniques like the doubled SDS- (16) and 16-benzyldimethyl-n-hexadecylammonium chloride/SDS-PAGE (17) represent an improvement for hydrophobic proteins. Advances in the nLC separation of hydrophobic peptides, e.g. the separation at elevated temperatures (18) and the use of LC-compatible detergents (19), yielded significant success. When combining both prominent separation techniques, the one-dimensional SDS-LC analysis proved to be more effective than 2D PAGE as well (20, 21).One of the remaining steps still offering room for improvements is the proteolytic procedure. The original multidimensional protein identification technique using trypsin has been successfully improved by the application of proteinase K under high pH conditions, yielding an increased number of membrane protein identifications (22). Further modification of this method by recleaving the isolated membranous parts with cyanogen bromide increased the accessibility to membrane-spanning peptides (18).Despite the suitability of proteinase K for the shotgun analysis of membrane proteomes, trypsin is the prevalent enzyme choice in most current proteomics approaches because of its very specific cleavage behavior. Calculations have implied that alternative proteases are preferentially suited for the analysis of membrane proteomes (23). Proteases other than trypsin have been utilized only to a small degree and mostly for the targeted analysis of protein complexes. Pepsin, for example, was used for the characterization of an aquaporin (24), and elastase and subtilisin were used as proteases in a triple digest approach of protein complexes and lens tissue (25). Further improvements in the accessibility of the membrane proteome have been shown for tryptic (26, 27) and tryptic/chymotryptic (28) digests by performing the proteolytic treatment in the presence of methanol.During membrane proteomics method development, purple membranes from Halobacterium sp. NRC-1, consisting to a large extent of the H⁺-ATPase bacteriorhodopsin, have widely been used as reference in a variety of cases. Full BR sequence coverage has been reported by several publications using different techniques (27, 29). Such exorbitant sequence coverage amounts are only achievable for the most abundant proteins within a complex mixture. The identification of less expressed proteins, which certainly are more in the researcher''s interest, occurs via lower peptide numbers (27).Generally the basic tryptic cleavage sites are predominantly located in the loops facing the cytoplasm and to a lesser extent in the extracellular or periplasmic loops but are very scarce within the transmembrane helix stretches. This mostly limits the potential tryptic fragments to loop components and larger peptides containing at least one TM helix. The use of another protease, preferentially cleaving after neutral aliphatic residues, should not succumb to this lack of cleavage sites.One of the previously mentioned proteases, porcine pancreatic elastase, was reported to possess potential cleavage specificity at the carboxyl-terminal side of small neutral amino acids (30). It has been used previously for the examination of single protein phosphorylations (31) but was described not to be suited for the cleavage of complex membrane-containing samples because of a supposedly limited activity when applied to them (22). Despite this finding, elastase has been successfully utilized in a mass spectrometric analysis as early as 1974 when it was regarded as an ideal protease for future mass spectrometric studies (32). At the same time, most of the experiments to characterize elastase by analyzing its S₁ pocket (for nomenclature, see Ref. 33) binding capabilities (34) as well as cleavage preferences of ester and protein substrates (35–39) were performed.Based on previous research concerning elastase, we set up an nLC-based membrane proteomics analysis. This large data set was used to characterize the protease behavior of elastase and the physicochemical properties of the detected peptides. The PM model was used to establish a method to analyze more complex Corynebacterium glutamicum membranes, which have been analyzed previously using different 2D techniques (7, 28). We demonstrated that a combination of elastase and methanol is particularly suitable for an nLC-based membrane proteome analysis and results in a significantly increased number of TM peptides. Additionally the promising PMF application of elastase digests is discussed.     

Reproductive tactics under severe egg predation: an eider’s dilemma

Parental defence against predators may increase offspring survival but entail other costs. Egg predation is frequent early in the laying sequence of the common eider, which differs in this and in several other ways from most other waterfowl. We test the hypothesis that permanent presence at the nest from the second or third egg is an adaptation for reducing egg predation in eiders. Two other alternative hypotheses for lower predation at later nest stages are early predation loss of the most vulnerable nests and seasonal decrease in predation risk. Analyses of predation rates at the one-egg and later stages refute these two alternatives. Early nest attendance by eider females is estimated to increase clutch survival by about 20% in four-egg and 35% in five-egg clutches, albeit probably at a cost of smaller clutch size.