Crop identity and memory effects on aboveground arthropods in a long‐term crop rotation experiment

Agricultural landscapes are globally dominated by monocultures under intensive management. This is one of the main reasons for biodiversity loss and insect population decline in many regions all over the world. Agroecosystem biodiversity in these areas can be enhanced by cropping system diversification, such as crop rotations. Yet, long‐term studies on effects of crop rotations on aboveground agrobiodiversity are lacking. We set up a 10‐year long‐term crop rotation experiment in Central Germany and monitored the temporal dynamics of aboveground arthropods over a full cultivation period to investigate influence of current and preceding crop identity and cropping system diversification on activity density, species richness, and community structure. We found that species composition was strongly influenced by currently grown crop although effect on arthropods varied between species groups. Especially, winter oilseed rape strongly affects arthropod community structure. Interestingly, we were also able to show an influence of the preceding crops, indicating an ecological memory effect in the aboveground arthropod community. Our results show that crop identity of both currently and previously grown crops in crop rotations may lead to an increase in arthropod activity density and changes in species composition. Diversified crop rotations including appropriate crops can be an easily implemented tool to increase arthropod biodiversity and biomass at large spatial and temporal scales, particularly in areas dominated by a single crop (e.g., wheat, maize). Our results may help to design optimized crop rotations for large‐scale enhancement of insect biodiversity in agroecosystems.     

XT-II, the second isoform of human peptide-O-xylosyltransferase, displays enzymatic activity

Peptide O-xylosyltransferase (EC 2.4.2.26) is the first enzyme required for the generation of chondroitin and heparan sulfate glycosaminoglycan chains of proteoglycans. Cloning of cDNAs has previously shown that, whereas invertebrates generally have a single xylosyltransferase gene, vertebrate genomes encode two similar proteins, xylosyltransferase I and II (XT-I and XT-II). To date, enzymatic activity has only been demonstrated for the human XT-I, Caenorhabditis SQV-6, and Drosophila OXT isoforms. In the present study, we demonstrate that a soluble form of human XT-II expressed in the xylosyltransferase-deficient pgsA-745 (S745) Chinese hamster ovary cell line is indeed capable of catalyzing the transfer of xylose to a variety of peptide substrates; its enzyme activity was also proven using a Pichia-expressed form of XT-II. Its pH, temperature, and cation dependences are similar to those of XT-I expressed in either mammalian cells or yeast. Our data suggest that XT-I and XT-II are, at least in vitro, functionally identical.     

Radiochromatographic assay of metabolites of the oostatic peptide labeled in different positions of the peptide chain

Reversed-phase high-performance liquid radio-chromatography (radio-HPLC) was set up to detect the time course of labeled degradation product formation of the pentapeptide H-Tyr-Asp-Pro-Ala-Pro-OH (5P), which has oostatic effects in different insect species. The detection limit of the system was in the range of 80-150 Bq. To follow formation of the degradation products, three amino acid residues in 5P were independently tritiated: Tyr1, Pro3 and Pro5. Each of the three tritiated peptides was analyzed after incubation with fresh hemolymph or ovaries of Neobellieria bullata. In the incubation mixture, free terminal amino acids and shortened sequences of 5P were identified. A metabolite of tyrosine represented the only exception; it was finally identified as water using degradation of [3H]Tyr by tyrosinase. Metabolic degradation of [3H]Tyr-5P was found to be considerably quicker than that of H-[3H]Tyr-Asp-Pro-Ala-OH (4P). The degradation of 5P was considerably slower in ovaries in comparison to hemolymph.     

Applications of field-flow fractionation in proteomics: presence and future

Field-flow fractionation (FFF) represents a group of elution separation methods where external force fields act perpendicularly on analytes in a carrier liquid flows with nonuniform velocity profiles. It is an elution separation method that enables to separate analytes in relatively short times and collect fractions for further characterization or for investigation of their properties. Other advantages of FFF are small consumption of samples and gentle experimental conditions. These make FFF uniquely qualified for separation and purification of biological samples. The most promising are applications of different variants of flow FFF utilizing a cross flow through membrane channel walls to separate proteins. The separation is based on differences in protein diffusion coefficients, which allows calculating the size of macromolecules. Other FFF techniques (e.g., electrical, isoelectric, and sedimentation FFF) were also used for separation of biomolecules. FFF appears to be not only promising rapid technique for protein separation but it offers some other advantages in sample preparation, especially, focusing (hyperlayer) FFF techniques that enable preparation of homogeneous fractions of cells. Selected applications of FFF to protein analysis are described and future trends in application of FFF to proteomics are discussed.     

Inhibition of TGF-beta2 with AP 12009 in recurrent malignant gliomas: from preclinical to phase I/II studies

Transforming growth factor-beta2 (TGF-beta2) is known to suppress the immune response to cancer cells and plays a pivotal role in tumor progression by regulating key mechanisms including proliferation, metastasis, and angiogenesis. For targeted protein suppression the TGF-beta2-specific antisense oligodeoxynucleotide AP 12009 was developed. In vitro experiments have been performed to prove specificity and efficacy of the TGF-beta2 inhibitor AP 12009 employing patient-derived malignant glioma cells as well as peripheral blood mononuclear cells (PBMCs) from patients. Clinically, the antisense compound AP 12009 was assessed in three Phase I/II-studies for the treatment of patients with recurrent or refractory malignant (high-grade) glioma WHO grade III or IV. Although the study was not primarily designed as an efficacy evaluation, prolonged survival compared to literature data and response data were observed, which are very rarely seen in this tumor indication. Two patients experienced long-lasting complete tumor remissions. These results implicate targeted TGF-beta2-suppression using AP 12009 as a promising novel approach for malignant gliomas and other highly aggressive, TGF-beta-2-overexpressing tumors.     

A new rodent species of the genus Mus (Rodentia: Muridae) confirms the biogeographical uniqueness of the isolated forests of southern Ethiopia

Organisms Diversity & Evolution - The Ethiopian highlands represent the largest part of the Eastern Afromontane Biodiversity Hotspot (EAMBH). Their fauna and flora are largely unique....     

Ecological Succession of a Relict Central European Peat Bog and Variability of Its Insect Biodiversity

The isolated habitat of the ervené Blato bog (South Bohemia, Czech Republic) and its relict insect fauna have been the subject of long-term monitoring. The species composition and abundance of Lepidoptera (light traps) and Coleoptera (pitfall traps) were monitored for 4 years (1994–1997) simultaneously on two sites – in the edaphic climax pine forest and in wetland successional habitats. The method of statistical evaluation by RDA and CCA ordination, representing the habitat preference of species of Coleoptera (Carabidae only) and Lepidoptera (all nocturnal phototactic taxa) between the edaphic climax forest and succession stages, was used. All categories of the peatland taxa (tyrphobiontic, tyrphophilous and tyrphoneutral species) were analysed. Ten highly stenotopic tyrphobiontic species and 23 tyrphophilous species of Lepidoptera (out of 487) were most characteristic of the bog habitat. Only two tyrphophilous carabid species (out of 20) were characteristic of the bog. The most important relict species (tyrphobionts) of Lepidoptera are most diverse and abundant within the successional habitats and in the open wet forest. The relict fauna of the closed climax pine forest is much less diverse and composed mostly of abundant tyrphophilous and tyrphoneutral forest species. Preservation or restoration of sufficiently constant hydrological conditions, which prevents formation of the closed forest, is the basic management for habitat conservation of all relict tyrphobiontic species of the ervené Blato bog and similar peat land habitat islands. The peat bog is a unified complex system of specific diverse and relict taxa. The most specific taxa are tyrphobiontic Lepidoptera, but a number of other vulnerable tyrphophilous and tyrphoneutral insects are associated with the peat bog as well.