Primary structure of apolipophorin-III from the greater wax moth,Galleria mellonella

The complete amino acid sequence of apolipophorin-III (apoLp-III), a lipid-binding hemolymph protein from the greater wax moth,Galleria mellonella, was determined by protein sequencing. The mature protein consists of 163 amino acid residues forming a protein of 18,075.5 Da. Its sequence is similar to apoLp-III from other Lepidopteran species, but remarkably different from the apoLp-IIIs of insects from other orders. As shown by mass spectrometric analysis, the protein carries no modifications. Thus, all of its known physiological functions, including its recently discovered immune response-stimulating activity, must reside in the protein itself.     

Past Experiences Affect Interaction Patterns Among Foragers and Hive-Mates in Honeybees

Social insect colonies face the challenge of adjusting the behavior of individuals performing various tasks to a changing environment. It has been shown in several species that characteristics of interaction patterns between nestmates provide social information that allows individuals to adjust their behavior in adaptive ways. A well-studied example is the modulation of recruitment by dancing in honeybees ( Apis mellifera ) in response to the time, the foragers have to search for unloading partners and the number of unloading bees. Here we tested if experiences that hive bees acquired during past social interactions affect interactions with the incoming foragers. Bees returning with food containing a floral scent that was familiar to the hive bees from previous interactions had more food receivers during unloading and more followers during dancing displays compared with foragers returning with food containing a novel scent or unscented food. We also confirm that the number of receivers during food unloading is positively related to the motivation to dance immediately after unloading. Our results show that prior social experiences affect the ways in which individuals interact in the context of honeybee nectar collection and, therefore, how learning in hive bees contributes to the organization of this collective task.     

Lack of evidence from studies of soluble protein fragments that Knops blood group polymorphisms in complement receptor-type 1 are driven by malaria

Complement receptor-type 1 (CR1, CD35) is the immune-adherence receptor, a complement regulator, and an erythroid receptor for Plasmodium falciparum during merozoite invasion and subsequent rosette formation involving parasitized and non-infected erythrocytes. The non-uniform geographical distribution of Knops blood group CR1 alleles Sl1/2 and McC^a/b may result from selective pressures exerted by differential exposure to infectious hazards. Here, four variant short recombinant versions of CR1 were produced and analyzed, focusing on complement control protein modules (CCPs) 15–25 of its ectodomain. These eleven modules encompass a region (CCPs 15–17) key to rosetting, opsonin recognition and complement regulation, as well as the Knops blood group polymorphisms in CCPs 24–25. All four CR1 15–25 variants were monomeric and had similar axial ratios. Modules 21 and 22, despite their double-length inter-modular linker, did not lie side-by-side so as to stabilize a bent-back architecture that would facilitate cooperation between key functional modules and Knops blood group antigens. Indeed, the four CR1 15–25 variants had virtually indistinguishable affinities for immobilized complement fragments C3b (K _D = 0.8–1.1 µM) and C4b (K _D = 5.0–5.3 µM). They were all equally good co-factors for factor I-catalysed cleavage of C3b and C4b, and they bound equally within a narrow affinity range, to immobilized C1q. No differences between the variants were observed in assays for inhibition of erythrocyte invasion by P. falciparum or for rosette disruption. Neither differences in complement-regulatory functionality, nor interactions with P. falciparum proteins tested here, appear to have driven the non-uniform geographic distribution of these alleles.     

Semiquantitative analysis of ECM molecules in the different cartilage layers in early and advanced osteoarthritis of the knee joint

The study was conducted to examine the expression of collagen type I and II in the different cartilage layers in relation to other ECM molecules during the progression of early osteoarthritic degeneration in human articular cartilage (AC). Quantitative real-time (RT)-PCR and colorimetrical techniques were used for calibration of Photoshop-based image analysis in detecting such lesions. Immunohistochemistry and histology were performed with 40 cartilage tissue samples showing mild (ICRS grade 1b) respectively moderate/advanced (ICRS grade 3a or 3b) (20 each) osteoarthritis compared with 15 healthy biopsies. Furthermore, we quantified our results on the gene expression of collagen type I and II and aggrecan with the help of real-time (RT)-PCR. Proteoglycan content was measured colorimetrically. The digitized images of histology and immunohistochemistry stains were analyzed with Photoshop software. T-test and Spearman correlation analysis were used for statistical analysis. In the earliest stages of AC deterioration the loss of collagen type II was associated with the appearance of collagen type I, shown by increasing amounts of collagen type I mRNA. During subsequent stages, a progressive loss of structural integrity was associated with increasing deposition of collagen type I as part of a natural healing response. A decrease of collagen type II is visible especially in the upper fibrillated area of the advanced osteoarthritic samples, which then leads to an overall decrease. Analysis of proteoglycan showed losses of the overall content and a loss of the classical zonal formation. Correlation analysis of the proteoglycan Photoshop measurements with the RT-PCR revealed strong correlation for Safranin O and collagen type I, medium for collagen type II, alcian blue and glycoprotein but weak correlation with PCR aggrecan results. Photoshop based image analysis might become a valuable supplement for well known histopathological grading systems of lesioned articular cartilage. The evidence of collagen type I production early in the OA disease process coupled with the ability of chondrocytes to up-regulate collagen type II production suggests that therapeutic agents that suppress collagen type I production and increase collagen type II production may enable chondrocytes to generate a more effective repair response.     

Fungus-specific microsatellite primers of lichens: application for the assessment of genetic variation on different spatial scales in Lobaria pulmonaria

We isolated 12 microsatellite loci for the epiphytic lichen-forming ascomycete Lobaria pulmonaria and studied their patterns of variation within and among populations from Canada and Switzerland. Even though several microsatellites exhibited high levels of variability at different spatial scales, we did not find any evidence for intrathalline variation. Most of the genetic variation was attributed to differences among individuals within populations. High genetic variation was also detected among L. pulmonaria samples taken from individual trees, suggesting that either multiple colonization events had occurred or that local recombination is frequent. The geographically structured distribution of alleles from several microsatellites indicated that L. pulmonaria from Canada and Switzerland represent two distinct evolutionary lineages. The potential to identify multiple alleles, and their transferability to closely related species, make microsatellites an ideal tool to study dispersal, population differentiation, and microevolution in lichens.     

Molecular phylogeny of songbirds (Aves: Passeriformes) and the relative utility of common nuclear marker loci

While the monophyly of the largest avian order Passeriformes as well as its suborders suboscines (Tyranni) and oscines (Passeri) is well established, lower phylogenetic relationships of this fast radiated taxon have been a continuous matter of debate, especially within the suborder oscines. Many studies analyzing phylogenetic relationships of the Passeriformes using molecular markers have been published, which led to a better resolved phylogeny. Conflicting hypotheses and still remaining uncertainties, especially within the Passerida, have repeatedly stimulated further research with additional new markers. In the present study we used a combination of established molecular markers (RAG‐1, RAG‐2, c‐myc) and the recently introduced ZENK. We accomplished phylogenetic analyses using maximum parsimony, maximum likelihood and Bayesian inference, both separately for all genes and simultaneously. To assess the phylogenetic utility of the different genes in avian systematics we analyzed the influence of each data partition on the phylogenetic tree yielded by the combined approach using partitioned Bremer support. Compared with the other single gene analyses, the ZENK trees exhibited by far the best resolution and showed the lowest amount of homoplasy. Our data indicate that this gene is—at least in passerines—suitable for inference of even old taxonomic splits. Our combined analysis yields well‐supported phylogenetic hypotheses for passerine phylogeny and apart from corroborating recently proposed hypotheses on phylogenetic relationships in the Passeriformes we provide evidence for some new hypotheses. The subdivision of the Passerida into three superfamilies, Sylvioidea, Passeroidea and Muscicapoidea, the first as sister to the two latter groups is strongly supported. We found evidence for a split between Paridae and the remaining Sylvioidea. © The Willi Hennig Society 2007.     

Activation Energies from Transition Path Sampling Simulations

We derive an new expression for the calculation of activation energies within the framework of transition path sampling. Using this expression one can determine activation energies without knowledge of the reaction mechanism, which is often unavailable for processes occurring in complex systems. Since in this method activation energies are calculated directly from path averages, no computationally expensive calculation of reaction rate constants is necessary. As an illustrative example, we determine the activation energy for the isomerization of a model diatomic immersed in a bath of repulsive soft particles.     

Endohexosaminidase-catalysed glycosylation with oxazoline donors: effects of organic co-solvent and pH on reactions catalysed by Endo A and Endo M

The synthetic efficiency of endohexosaminidase-catalysed glycosylation reactions using N-glycan oxazolines as donors was investigated as two reaction parameters were varied. Both the addition of quantities of an organic co-solvent and modulation of reaction pH between 6.5 and 8.0 were found to have different effects on reactions catalysed by either Endo A (and two available mutants) or Endo M, indicating subtle differences between these two family GH85 enzymes. Fine tuning of reaction pH, or the addition of quantities of an organic co-solvent, resulted in beneficial increases in achievable synthetic efficiency by effecting a reduction in the rate of competitive hydrolytic processes.