Detection of nanomolar concentrations of copper(II) with a Tb-quinoline-2-one probe using luminescence quenching or luminescence decay time.

We present a time-resolved (gated) luminescence-based method for determination of Cu2+ ions in microtiterplate format in the nanomolar concentration range using the novel long-lived terbium-[1-methyl-4-hydroxy-3-(N-2-ethyl-5-aminothiadiazolyl-)-carbamoyl-quinoline-2-one] (TbL) complex. The probe works best in Tb:L = 1:2 stoichiometry at neutral pH. The dynamic range is from 10 to 300 nmol L(-1) of Cu2+ and the limit of detection is 4.

Hyperoxia-induced neurodegeneration as a tool to identify neuroprotective genes in Drosophila melanogaster.

Oxidative stress has been reported to be a common underlying mechanism in the pathogenesis of many neurodegenerative disorders such as Alzheimer, Huntington, Creutzfeld-Jakob, and Parkinson disease. Despite the increasing number of articles showing a correlation between oxidative damage and neurodegeneration little is known about the genetic elements that confer protection against the deleterious effects of an oxidative imbalance in neurons. We show that oxygen-induced damage is a direct cause of brain degeneration in Drosophila and establish an experimental setup measuring dopaminergic neuron survival to model oxidative stress-induced neurodegeneration in flies.

Scent of a queen-cuticular hydrocarbons specific for female reproductives in lower termites.

In social insects, it is assumed that signals of the queen inform nestmates about her reproductive status. Thus, workers forego their own reproduction if the queen signals high fertility. In hemimetabolous termites, little is known about reproductive inhibition, but evidence exists for a royal-pair control.

The LIM-homeodomain transcription factor LMX1B regulates expression of NF-kappa B target genes.

LMX1B is a LIM-homeodomain transcription factor essential for development. Putative LMX1B target genes have been identified through mouse gene targeting studies, but their identity as direct LMX1B targets remains hypothetical. We describe here the first molecular characterization of LMX1B target gene regulation.

A dicarboxylate/4-hydroxybutyrate autotrophic carbon assimilation cycle in the hyperthermophilic Archaeum Ignicoccus hospitalis.

Ignicoccus hospitalis is an anaerobic, autotrophic, hyperthermophilic Archaeum that serves as a host for the symbiotic/parasitic Archaeum Nanoarchaeum equitans. It uses a yet unsolved autotrophic CO(2) fixation pathway that starts from acetyl-CoA (CoA), which is reductively carboxylated to pyruvate. Pyruvate is converted to phosphoenol-pyruvate (PEP), from which glucogenesis as well as oxaloacetate formation branch off.

Differences in intermale aggression are accompanied by opposite vasopressin release patterns within the septum in rats bred for low and high anxiety.

Several studies suggest a role for arginine vasopressin (AVP), particularly in the lateral septum, in the regulation of intermale aggression. We used intracerebral microdialysis to monitor the local in vivo AVP release within the mediolateral septum of adult male Wistar rats bred for low (LAB) or high (HAB) anxiety-related behaviour during exposure to the resident-intruder test. LAB residents showed a significantly higher level of aggression than HAB residents, as reflected by more time spent with lateral threat, offensive upright and total aggressive behaviour as well as by more attacks and a shorter attack latency.

Quantum dots - nano-sized probes for the exploration of cellular and intracellular targeting.

Nanoparticles emerged as promising tool in drug targeting, since, after appropriate modification, they are able to deliver their payload to specific sites, like tissues, cells, or even certain cellular organelles. In this context, the delivery of nanoparticles from the circulation into the target cells represents a crucial step. Here, model drug delivery systems such as quantum dots are ideal candidates to elucidate this process in more detail, since they provide outstanding features like a small and uniform size, unique optical properties for most sensitive detection and modifiable surfaces.

Breaking up the correlation between efficacy and toxicity for nonviral gene delivery.

Nonviral nucleic acid delivery to cells and tissues is considered a standard tool in life science research. However, although an ideal delivery system should have high efficacy and minimal toxicity, existing materials fall short, most of them being either too toxic or little effective. We hypothesized that disulfide cross-linked low-molecular-weight (MW) linear poly(ethylene imine) (MW<4.

Mechanistic insights into linear polyethylenimine-mediated gene transfer.

We recently debuted a variety of linear polyethylenimines (LPEIs) with low molecular weight as carriers for gene delivery. The highest transfection efficiency (approximately 44%) was obtained with LPEI 6.6 kDa, while the cytotoxicity remained low (approximately 90% of CHO-K1 cells survived the transfection procedure).

Long-term stable fibrin gels for cartilage engineering.

It is essential that hydrogel scaffold systems maintain long-term shape stability and mechanical integrity for applications in cartilage tissue engineering. Within this study, we aimed at the improvement of a commercially available fibrin gel in order to develop a long-term stable fibrin gel and, subsequently, investigated the suitability of the optimized gel for in vitro cartilage engineering. Only fibrin gels with a final fibrinogen concentration of 25mg/ml or higher, a Ca(2+) concentration of 20mm and a pH between 6.

Low inborn anxiety correlates with high intermale aggression: link to ACTH response and neuronal activation of the hypothalamic paraventricular nucleus.

Aggression constitutes a central problem in several psychopathologies, including anxiety and depression disorders and antisocial behaviors. In particular, the activity of the hypothalamic-pituitary-adrenocortical (HPA) axis has been associated with aggression-related disorders. The present study assessed whether genetically determined levels of anxiety-related behavior influence the level of intermale aggression and whether this is associated with differences in neuroendocrine responsiveness and neuronal activation in the brain.

Pir proteins of Saccharomyces cerevisiae are attached to beta-1,3-glucan by a new protein-carbohydrate linkage.

A family of covalently linked cell wall proteins of Saccharomyces cerevisiae, called Pir proteins, are characterized by up to 10 conserved repeating units. Ccw5/Pir4p contains only one complete repeating sequence and its deletion caused a release of the protein into the medium. The exchange of each of three glutamines (Gln69, Gln74, Gln76) as well as one aspartic acid (Asp72) within the repeating unit leads to a loss of the protein from the cell wall.

Gene delivery with low molecular weight linear polyethylenimines.

Background: Linear polyethylenimine (LPEI) with a molecular weight (MW) of 22 kDa has been described as having a superior ability to induce gene transfer compared to its branched form. However, the transfection efficiency of the polymer cannot be enhanced beyond a certain limit due to cytotoxicity. We explored the potential of utilizing LPEIs with MWs ranging from 1.

Mediating specific cell adhesion to low-adhesive diblock copolymers by instant modification with cyclic RGD peptides.

One promising strategy to control the interactions between biomaterial surfaces and attaching cells involves the covalent grafting of adhesion peptides to polymers on which protein adsorption, which mediates unspecific cell adhesion, is essentially suppressed. This study demonstrates a surface modification concept for the covalent anchoring of RGD peptides to reactive diblock copolymers based on monoamine poly(ethylene glycol)-block-poly(D,L-lactic acid) (H(2)N-PEG-PLA). Films of both the amine-reactive (ST-NH-PEG(2)PLA(20)) and the thiol-reactive derivative (MP-NH-PEG(2)PLA(40)) were modified with cyclic alphavbeta3/alphavbeta5 integrin subtype specific RGD peptides simply by incubation of the films with buffered solutions of the peptides.

Basic fibroblast growth factor enhances PPARgamma ligand-induced adipogenesis of mesenchymal stem cells.

Mesenchymal stem cells (MSCs) are capable of differentiating into a variety of lineages, including bone, cartilage, or fat, depending on the inducing stimuli and specific growth and differentiation factors. It is widely acknowledged that basic fibroblast growth factor (bFGF) modulates chondrogenic and osteogenic differentiation of MSCs, but thorough investigations of its effects on adipogenic differentiation are lacking. In this study, we demonstrate on the cellular and molecular level that supplementation of bFGF in different phases of cell culture leads to a strong enhancement of adipogenesis of MSCs, as induced by an adipogenic hormonal cocktail.

Polyplexes of polyethylenimine and per-N-methylated polyethylenimine-cytotoxicity and transfection efficiency.

For non-viral gene delivery, the carriers for DNA transfer into cells must be vastly improved. The branched cationic polymer polyethylenimine has been described as an efficient gene carrier. However, polyethylenimine was demonstrated to mediate substantial cytotoxicity.

The Drosophila carbonyl reductase sniffer prevents oxidative stress-induced neurodegeneration.

A growing body of evidence suggests that oxidative stress is a common underlying mechanism in the pathogenesis of neurodegenerative disorders such as Alzheimer's, Huntington's, Creutzfeld-Jakob and Parkinson's diseases. Despite the increasing number of reports finding a causal relation between oxidative stress and neurodegeneration, little is known about the genetic elements that confer protection against the deleterious effects of oxidation in neurons. We have isolated and characterized the Drosophila melanogaster gene sniffer, whose function is essential for preventing age-related neurodegeneration.

Does she smell like a queen? Chemoreception of a cuticular hydrocarbon signal in the ant Pachycondyla inversa.

Primitive ant societies, with their relatively simple social structure, provide an opportunity to explore the evolution of chemical communication, in particular of mechanisms underlying within-colony discrimination. In the same colony, slight differences in individual odours can be the basis for discrimination between different castes, classes of age and social status. There is some evidence from correlative studies that such inter-individual variation is associated with differences in reproductive status, but direct proof that certain chemical compounds are detected and recognized by ants is still lacking.

Towards biomimetic scaffolds: anhydrous scaffold fabrication from biodegradable amine-reactive diblock copolymers.

The development of biomimetic materials and their processing into three-dimensional cell carrying scaffolds is one promising tissue engineering strategy to improve cell adhesion, growth and differentiation on polymeric constructs developing mature and viable tissue. This study was concerned with the fabrication of scaffolds made from amine-reactive diblock copolymers, N-succinimidyl tartrate monoamine poly(ethylene glycol)-block-poly(D,L-lactic acid), which are able to suppress unspecific protein adsorption and to covalently bind proteins or peptides. An appropriate technique for their processing had to be both anhydrous, to avoid hydrolysis of the active ester, and suitable for the generation of interconnected porous structures.

Source-sink regulation by sugar and stress.

The regulation of carbon partitioning between source and sink tissues in higher plants is not only important for plant growth and development, but insight into the underlying regulatory mechanism is also a prerequisite to modulating assimilate partitioning in transgenic plants. Hexoses, as well as sucrose, have been recognised as important signal molecules in source-sink regulation. Components of the underlying signal transduction pathways have been identified and parallels, as well as distinct differences, to known pathways in yeast and animals have become apparent.