Structural requirements for mutational lutropin/choriogonadotropin receptor activation

Different activation mechanisms of glycoprotein hormone receptors, which are members of the G protein-coupled receptor superfamily, have been proposed. For example, the large ectodomain of glycoprotein hormone receptors may function as an inverse agonist keeping the transmembrane domain in an inactive conformation. To provide support for this hypothesis, we have generated different lutropin/choriogonadotropin receptor (LHR) constructs lacking the ectodomain. Although some ectodomain-deficient LHR constructs were targeted to the cell surface, cAMP levels remained unchanged under basal conditions and agonist application but could be increased by a mutation within the transmembrane domain 6 (D578H). Taking advantage of a constitutive activating mutation (S277N) located in the extracellular domain, we showed that the intact leucine-rich repeat-containing ectodomain is essential for constitutive activation of the LHR by mutation of the hinge region. Our findings support an activation scenario in which agonist binding or mutational alterations expose a structure within the ectodomain, which then activates the transmembrane core.     

Guidelines for consistent reporting of exchanges/to nature within life cycle inventories (LCI)

Data availability and data quality are still critical factors for successful LCA work. The SETAC-Europe LCA Working Group ‘Data Availability and Data Quality’ has therefore focused on ongoing developments toward a common data exchange format, public databases and accepted quality measures to find science-based solutions than can be widely accepted. A necessary prerequisite for the free flow and exchange of life cycle inventory (LCI) data and the comparability of LCIs is the consistent definition, nomenclature, and use of inventory parameters. This is the main subject of the subgroup ‘Recommended List of Exchanges’ that presents its results and findings here:

Glucagon-like peptide 1: evolution of an incretin into a treatment for diabetes

Glucagon-like peptide 1 (GLP-1) is a product of proglucagon that is secreted by specialized intestinal endocrine cells after meals. GLP-1 is insulinotropic and plays a role in the incretin effect, the augmented insulin response observed when glucose is absorbed through the gut. GLP-1 also appears to regulate a number of processes that reduce fluctuations in blood glucose, such as gastric emptying, glucagon secretion, food intake, and possibly glucose production and glucose uptake. These effects, in addition to the stimulation of insulin secretion, suggest a broad role for GLP-1 as a mediator of postprandial glucose homeostasis. Consistent with this role, the most prominent effect of experimental blockade of GLP-1 signaling is an increase in blood glucose. Recent data also suggest that GLP-1 is involved in the regulation of beta-cell mass. Whereas other insulinotropic gastrointestinal hormones are relatively ineffective in stimulating insulin secretion in persons with type 2 diabetes, GLP-1 retains this action and is very effective in lowering blood glucose levels in these patients. There are currently a number of products in development that utilize the GLP-1-signaling system as a mechanism for the treatment of diabetes. These compounds, GLP-1 receptor agonists and agents that retard the metabolism of native GLP-1, have shown promising results in clinical trials. The application of GLP-1 to clinical use fulfills a long-standing interest in adapting endogenous insulinotropic hormones to the treatment of diabetes.     

Ecologically relevant stress resistance: from microarrays and quantitative trait loci to candidate genes — A research plan and preliminary results using<Emphasis Type="Italic">Drosophila</Emphasis> as a model organism and climatic and genetic stress as model stresses

We aim at studying adaptation to genetic and environmental stress and its evolutionary implications at different levels of biological organization. Stress influences cellular processes, individual physiology, genetic variation at the population level, and the process of natural selection. To investigate these highly connected levels of stress effects, it is advisable - if not critical - to integrate approaches from ecology, evolution, physiology, molecular biology and genetics. To investigate the mechanisms of stress resistance, how resistance evolves, and what factors contribute to and constrain its evolution, we use the well-defined model systems ofDrosophila species, representing both cosmopolitan species such asD. melanogaster with a known genome map, and more specialized and ecologically well described species such as the cactophilicD. buzzatii. Various climate-related stresses are used as model stresses including desiccation, starvation, cold and heat. Genetic stress or genetic load is modelled by studying the consequences of inbreeding, the accumulation of (slightly) deleterious mutations, hybridization or the loss of genetic variability. We present here a research plan and preliminary results combining various approaches: molecular techniques such as microarrays, quantitative trait loci (QTL) analyses, quantitative PCR, ELISA or Western blotting are combined with population studies of resistance to climatic and genetic stress in natural populations collected across climatic gradients as well as in selection lines maintained in the laboratory.     

Synthesis and radioiodination of selective ligands for the dopamine D3 receptor subtype

Starting from FAUC 365, a series of iodine substituted heteroaryl carboxamides has been synthesized revealing high affinity and selectivity for the dopamine D3 receptor. Binding data showed a 15-560-fold selectivity for the dopamine D3 over D2. A 2,3-dichloro substitution pattern on the phenylpiperazine moiety led to the highest subtype selectivity, whereas the 2-methoxy substituted compounds showed superior D3 affinity. Suitable precursors were radioiodinated with high radiochemical yields (53-85%) leading to potential imaging agents for the D3 receptor by SPET.     

Synthesis of dimeric acridine derived antivirals

A series of antiviral compounds consisting of an intercalating acridine derived part, a spacer region and a reactive EDTA derived conjugate was synthesized in an easy sequence starting from 1,omega-alkyldiamines. As shown in model screenings, in the presence of ascorbic acid the Fe-complexes of these compounds reduced the phage-titer of MS2-phages by >8 logarithmic decades.     

Animal-free production of ccc-supercoiled plasmids for research and clinical applications

The topological structure of plasmid DNA can be characterized by capillary gel electrophoresis (CGE analysis)-an important tool for quality control and stability assessments in DNA storage or application. Hence, a large-scale manufacturing process was developed that allows the removal of undesired open circular (oc) or linear plasmid topologies, bacterial genomic DNA, RNA, proteins as well as lipopolysaccharides (endotoxins) and results in obtaining supercoiled (covalently closed circular, ccc) plasmid DNA in a pure form without using any animal-derived substances. Using CGE, the development and in-line monitoring for pharmaceutical plasmid production starting from fermentation control throughout the whole manufacturing process including the formulated and filled product can be performed the first time in a way conforming to good manufacturing practices (GMP). Plasmid stability data were obtained from analysis of shear effects influencing the plasmid quality in DNA drug delivery formulation and application (e.g. gene gun or jet injection). The physical stability of plasmid DNA is for the first time evaluated in DNA storage experiments on the level of different plasmid forms.     

Flexible automation of cell culture and tissue engineering tasks

Until now, the predominant use cases of industrial robots have been routine handling tasks in the automotive industry. In biotechnology and tissue engineering, in contrast, only very few tasks have been automated with robots. New developments in robot platform and robot sensor technology, however, make it possible to automate plants that largely depend on human interaction with the production process, e.g., for material and cell culture fluid handling, transportation, operation of equipment, and maintenance. In this paper we present a robot system that lends itself to automating routine tasks in biotechnology but also has the potential to automate other production facilities that are similar in process structure. After motivating the design goals, we describe the system and its operation, illustrate sample runs, and give an assessment of the advantages. We conclude this paper by giving an outlook on possible further developments.     

Dynamic of ligand binding to Drosophila melanogaster ecdysteroid receptor

Ligand binding to ecdysone receptor (EcR) is an autonomous function of the ligand binding domain (LBD) and is not modified by other receptor domains or tags fused to the LBD. Association and dissociation velocity of hormone to EcR was studied in the absence and presence of its main dimerization partner Ultraspiracle (USP). Mutational analysis of the EcR(LBD) revealed that ligand entry and exit is affected differently by the same point mutation, indicating that different pathways are used for association and dissociation of the ligand. Heterodimerization with wild type USP(LBD) increases ligand association to EcR(LBD) about fivefold and reduces dissociation 18-fold. Opposite effects of the same mutation (N626K) on dissociation velocity of ligand in EcR and EcR/USP indicate that not only hormone binding itself, but also the kinetic behaviour of ligand binding is modified by the dimerization partner. A general effect of the point mutations on the 3D architecture seems unlikely due to the highly selective effects on the kinetics of hormone binding.