Ansätze zur nachhaltigen Sicherung der botanischen Artenvielfalt auf Schutzäckern – eine Aufgabe für Biobetriebe?

Der drastische Artenrückgang unter den Ackerwildkräutern war Anlass zur Suche nach neuen Schutzkonzepten. Das Projekt „Errichtung eines bundesweiten Schutzgebietsnetzes für Ackerwildkräuter“ verfolgt das Ziel, ein nachhaltiges Schutzgebiets-Netzwerk zum Erhalt bedrohter Segetalarten in Deutschland zu konzipieren und umzusetzen. Eine Anzahl von mindestens 100 geeigneten Ackerstandorten („100 Äcker für die Vielfalt“) soll für eine „dauerhafte Sicherung“ selten gewordener Ackerwildkräuter unter Schutz gestellt werden und ihre spezielle, auf den Erhalt und Förderung der entsprechenden Arten ausgerichtete Bewirtschaftung langfristig sichergestellt werden. Ökologisch bewirtschaftete Felder sind dazu besonders geeignet. Das innovative Beispiel eines ökologisch wirtschaftenden Landwirts wird vorgestellt. Die Herausforderung ist die Sicherstellung des langfristigen Schutzes durch vertragliche Vereinbarungen

Exploring the potential of dialogical and trialogical systems in language learning: Web 1.0 and Web 2.0 applications in FL writing proficiency courses

The socio-constructivist approach has made a significant contribution to computer assisted language learning through its focus on peer collaboration and negotiation of meaning. The present paper shows how these insights can be applied to foster advanced foreign language (FL) writing skills. Based on our experience with FL writing proficiency courses in Flemish higher education, we discuss two practical applications of virtual learning environments (VLEs); the first may be described as “dialogical”, the second as “trialogical”, with wikis being the collaboratively created objects. Both types turn out to be useful in order to promote a closer integration of private and educational communication in the lives of “digital natives” studying a foreign language. Our first project involved e-mail tandem partnerships between Flemish majors of FL German and a group of L1 German peers taking a course on teaching German as a FL. The collaboration consisted mainly of the German group´s feedback on the Flemish students´ texts (descriptive, deliberative, persuasive). Communication was conducted both via a VLE and e-mail. The Flemish students documented the collaboration process, drafts and final versions of their texts in a portfolio. Problems encountered had to do with the difference in term dates between the two institutions, with a lack of teaching experience on the part of the German students, and with the fact that they did not know the Ghent students' L1, Dutch (making it difficult to diagnose L1 interference in the latter's errors); intercultural misunderstandings also occurred, caused by differing interpretations of irony. Our second project consisted in the joint creation of German FL wikis within groups of Flemish bachelor students. They collaboratively created wikis on recent “Words of the Year” of German-speaking countries, keeping in mind their peers' background knowledge. Besides peer-collaboration, peer-revision also played an important role, as the groups provided mutual feedback on their wiki´s. In our paper we present samples of wiki pages and peer feedback, and highlight some conclusions concerning the (rather divergent) appreciation of the project by the students as expressed in a post-hoc questionnaire. Both our applications demonstrate how the computer literacy acquired in private communication can be integrated into the teaching of FL writing in different ways. An obvious strength of the trialogical approach is that it allows teachers and learners to focus on writing processes. Since wikis also enable researchers to track the creation process, they can lead to new insights into the FL writing process and the negotiation involved in collaborative writing in general. On the other hand, applying Web 2.0 projects in higher education also implies new challenges to the institutional framework, from hard- and software through teacher training to curricula flexibility

Conjugates of lytic peptides and LHRH or βCG target and cause necrosis of prostate cancers and metastases

In a series of in vivo and in vitro experiments, it was shown that membrane disrupting lytic peptides (Hecate, Phor14, or Phor21) conjugated to a 15 amino acid segment of the β chain of CG or to LHRH were able to target and destroy hormone dependent and independent human prostate cancer xenografts in nude mice. In vitro sensitivity of the cells to the drugs was directly related to LH/CG receptor expression, and pretreatment in vitro or in vivo with estrogens or FSH to enhance LH/CG receptor expression capacity and increased sensitivity to the drugs. Administration of unconjugated Hecate and LHRH was ineffective. Most importantly, all of the lytic peptide-βCG conjugates tested were highly effective in destroying prostate cancer metastatic cells in lymph nodes, bones and lungs. © 2007 Elsevier Ireland Ltd. All rights reserved

Destruction of breast cancers and their metastases by lytic peptide conjugates in vitro and in vivo

In a series of in vivo and in vitro experiments, the concept has been established that breast cancer cells that express LH/CG or LHRH receptors can be targeted and destroyed by constructs consisting of a lytic peptide moiety and a 15-amino acid segment of the β-chain of CG or by an LHRH lytic peptide conjugate. Data obtained in vitro established the validity of this concept, showed the specificities of the Hecate-βCG, and Phor14 and Phor21-βCG conjugates in killing cells that express functional LH/CG receptors and proved that the LH/CG receptor capacity is directly related to the compound\u27s specificity. In in vivo experiments, Hecate-βCG, Phor14-βCG, and Phor21-βCG(ala) each caused highly significant reductions of tumor volume and tumor burden in nude mice bearing breast cancer xenografts; Hecate and Phor21 alone or conjugated with non-specific peptides were not effective. Most importantly, the lytic peptide conjugates were all highly effective in targeting and destroying disseminated breast cancer metastases in lymph nodes, bones, lungs and other organs. © 2006 Elsevier Ireland Ltd. All rights reserved

Membrane disrupting lytic peptide conjugates destroy hormone dependent and independent breast cancer cells in vitro and in vivo

We have prepared conjugates of a membrane disrupting lytic peptide (hecate) and a 15-amino acid segment of the β-chain of CG and hecate and the decapeptide, luteinizing hormone releasing hormone (LHRH). We have tested the concept that these conjugates will target breast cancer cells expressing LH/CG or LHRH receptors. In previous studies, we were able to destroy prostate cancers in vitro and in vivo with lytic peptide conjugates [1]. Hecate, hecate-βCG and LHRH-hecate were added to cultures of the human breast cancer cell lines MCF-7 and MDA-MB-435S. Hecate and its conjugates showed concentration dependent toxicity to both cell lines. The lytic peptide alone showed similar EC50 values for both cell lines; however, there was a significant difference between the EC50 values when the conjugates were tested. The hormone dependent MCF-7 cell line was less sensitive to the βCG conjugate than to the LHRH conjugate; the reverse was found for the hormone independent MDA-MB-435S cells. Removal of steroids decreased the sensitivity of MCF-7 cells to both lytic peptide conjugates and this sensitivity could be restored by adding estradiol. Activation of protein kinase C further increased the sensitivity to the drug. MDA-MB-435S xenografts were established in intact female athymic nude mice, which were treated once a week for 3 weeks with hecate-βCG via the lateral tail vein. The ability of hecate-βCG to destroy xenografts of human breast cancer cells (MDA-MB-435S) in nude mice was demonstrated for the first time. We conclude that hecate-βCG and LHRH-hecate conjugates could serve as useful drugs for the treatment of breast cancer

Effects of a lytic peptide conjugated to β hCG on ovarian cancer: Studies in vitro and in vivo

Objective. The aim of this study was to determine the in vitro and in vivo effects of the lytic peptide, hecate, alone and conjugated to a 15-amino-acid fragment of the β-chain of hCG (hecate-β hCG) on the ovarian carcinoma cell line NIH: OVCAR-3 and determine the expression of luteinizing hormone (LH)/human chorionic gonadotropin (hCG) receptors in cell cultures and tumor tissues. Methods. For in vitro studies, hecate or hecate-β hCG was added to cultures of ovarian cancer cells in the presence or absence of estradiol or follicle stimulating hormone. The cytotoxicity of lytic peptides was measured by trypan blue exclusion and lactate dehydrogenase release. For in vivo studies, OVCAR-3 xenografts were established in female athymic nude mice which were then treated once per week for 3 weeks with hecate or hecate-β hCG via the lateral tail vein. An immunohistochemical method was used to analyze the expression of LH/hCG receptor in tumor and culture cells. Results. In in vitro studies, both hecate-β hCG and hecate destroyed ovarian cancer cells (NIH: OVCAR-3) in a dose-dependent manner. Removal of steroids from the culture medium reduced the sensitivity of the OVCAR-3 cell line to the hecate-β hCG in a reversible manner. In in vivo studies, the average tumor volume and tumor burden in lytic peptide treated animals were reduced. In the groups of animals treated by hecate, hecate-β hCG, and estradiol + hecate-β hCG, tumor volumes after treatment expressed as a percentage of increase (197.4 ± 21.72, 199.0 ± 18.57, and 193.8 ± 22.94%, respectively) were reduced, compared to control (263.0 ± 21.72%) animals (P \u3c 0.05). Immunocytochemical studies revealed the expression of LH/hCG receptor protein in the OVCAR-3 cells and tumor tissues. Conclusion. Hecate-β hCG is a putative candidate for treating ovarian cancer. © 2002 Elsevier Science (USA)