A proteome map of the pituitary melanotrope cell activated by black‐background adaptation of Xenopus laevis

Upon transfer of Xenopus laevis from a white to a black background, the melanotrope cells in the pituitary pars intermedia secrete α‐melanocyte‐stimulating hormone, which stimulates dispersion of melanin pigment in skin melanophores. This adaptive behavior is under the control of neurotransmitters and neuropeptides of hypothalamic origin. The α‐melanocyte‐stimulating hormone‐producing cells and their hypothalamic control system provide an interesting model to study proteins required for biosynthetic and secretory processes involved in peptide hormone production and for brain–pituitary signaling. We present a 2‐D PAGE‐based proteome map of melanotrope cells from black‐adapted animals, identifying 204 different proteins by MS analysis.     

Cloning and characterization of a functional flavanone-3ß-hydroxylase gene from <Emphasis Type="Italic">Medicago truncatula</Emphasis>

As a key enzyme in the biosynthesis of flavonols, anthocyanidins and proanthocyanidins, flavanone-3ß-hydroxylase (F3H) plays very important roles in plant stress response. A putative flavanone-3ß-hydroxylase gene from Medicago truncatula (MtF3H), a model legume species, was identified from a bio-data analysis platform. It was speculated to be induced by salt stress based on the outcomes of the analysis platform. The complementary DNA (cDNA) consists of 1499 bp with an open reading frame (ORF) of 1098 bp, which encodes a putative protein of 365 amino acids with a molecular weight of about 41.36 kDa and an isoelectric point of 5.60. To measure the catalytic activity of the protein, the MtF3H gene was ligated to pYES2 vector and heterologously expressed in yeast. The recombinant protein converted naringen into dihydrokaempferol and displayed different enzymatic efficiencies with other flavanones, confirming that MtF3H coding a functional flavanone-3ß-hydroxylase. The expression pattern of the MtF3H gene was analyzed by comparative quantitative RT-PCR and a higher level of expression was observed in the roots than was observed in stems and leaves. Furthermore, the expression was induced by salt stress in the roots, and to a greater extent in the stems, but the response of the gene activity to salt stress in the stems was slower in the first 12 h following treatment when compared to the roots.     

Applying double-magnetic induction to measure head-unrestrained gaze shifts: calibration and validation in monkey

The double magnetic induction (DMI) method has successfully been used to record head-unrestrained gaze shifts in human subjects (Bremen et?al., J Neurosci Methods 160:75-84, 2007a, J Neurophysiol, 98:3759-3769, 2007b). This method employs a small golden ring placed on the eye that, when positioned within oscillating magnetic fields, induces orientation-dependent voltages in a pickup coil in front of the eye. Here we develop and test a streamlined calibration routine for use with experimental animals, in particular, with monkeys. The calibration routine requires the animal solely to accurately follow visual targets presented at random locations in the visual field. Animals can readily learn this task. In addition, we use the fact that the pickup coil can be fixed rigidly and reproducibly on implants on the animal's skull. Therefore, accumulation of calibration data leads to increasing accuracy. As a first step, we simulated gaze shifts and the resulting DMI signals. Our simulations showed that the complex DMI signals can be effectively calibrated with the use of random target sequences, which elicit substantial decoupling of eye- and head orientations in a natural way. Subsequently, we tested our paradigm on three macaque monkeys. Our results show that the data for a successful calibration can be collected in a single recording session, in which the monkey makes about 1,500-2,000 goal-directed saccades. We obtained a resolution of 30 arc minutes (measurement range [-60,+60]°). This resolution compares to the fixation resolution of the monkey's oculomotor system, and to the standard scleral search-coil method.     

Dioxo-triazines as a novel series of cathepsin K inhibitors

A novel dioxo-triazine series of cathepsin K inhibitors was identified from HTS. A rapid exploratory programme led to the discovery of potent and selective cathepsin K inhibitors, typified by compound 24 which displayed IC₅₀ values of 17 nM against catK and >10,000 nM in catL, catB and catS assays.     

The phylogenetic relationships of Przevalski's Finch Urocynchramus pylzowi,the most ancient Tibetan endemic passerine known to date

Competing systematic hypotheses have placed the Tibetan endemic Przevalski's Finch Urocynchramus pylzowi either with the Old World buntings (Emberizidae) or with the cardueline finches (Fringillidae, Carduelinae). Recent studies based on limited genetic evidence instead suggest an isolated position within Passeroidea and advocate a separate family, Urocynchramidae, as had been suggested much earlier on the grounds of morphology. We provide a time‐calibrated multi‐locus phylogeny for Passeroidea including Przevalski's Finch based on three mitochondrial markers and three nuclear introns that placed U. pylzowi in a clade together with Estrildidae, Viduidae and Ploceidae. A sister group relationship of U. pylzowi and weavers (Ploceidae) was concordant among three multilocus reconstructions but received only poor support. Divergence time estimates inferred from a fossil/biogeographical molecular dating approach suggested a late Oligocene split of U. pylzowi from its closest relatives at roughly 25 million years ago, making this the oldest known Tibetan endemic passerine. In addition to the molecular data, behavioural peculiarities and egg coloration further strengthen an isolated placement of U. pylzowi.     

Prediction of sequence-dependent and mutational effects on the aggregation of peptides and proteins

We have developed a statistical mechanics algorithm, TANGO, to predict protein aggregation. TANGO is based on the physico-chemical principles of beta-sheet formation, extended by the assumption that the core regions of an aggregate are fully buried. Our algorithm accurately predicts the aggregation of a data set of 179 peptides compiled from the literature as well as of a new set of 71 peptides derived from human disease-related proteins, including prion protein, lysozyme and beta2-microglobulin. TANGO also correctly predicts pathogenic as well as protective mutations of the Alzheimer beta-peptide, human lysozyme and transthyretin, and discriminates between beta-sheet propensity and aggregation. Our results confirm the model of intermolecular beta-sheet formation as a widespread underlying mechanism of protein aggregation. Furthermore, the algorithm opens the door to a fully automated, sequence-based design strategy to improve the aggregation properties of proteins of scientific or industrial interest.     

Long‐distance dispersal in Odonata: Examples from arid Namibia

We report cases of long‐distance dispersal in Odonata, some of which were directly observed by identifying single individuals of riverine species in unsuitable habitat, mostly desert, far distant from reproduction habitats. The shortest possible linear distances of the observation points to reproduction habitats were measured. Furthermore, established populations of riverine species were recorded in artificial lakes in central and southern Namibia far distant from the next regular reproduction sites. Our records demonstrate that single individuals of riverine species were probably covering distances of several hundred kilometres over arid landscape without any intervening possible reproduction habitat. Although it is likely that only small numbers of individuals of the river populations may disperse long distances, relatively recent colonizations of artificial habitats suggest that a few, or even single, dispersing individuals may lead to large‐scale‐range expansions.     

Cartilage tissue engineering: controversy in the effect of oxygen

Articular cartilage lacks the ability to repair itself and consequently defects in this tissue do not heal. Tissue engineering approaches, employing a scaffold material and cartilage producing cells (chondrocytes), hold promise for the treatment of such defects. In these strategies the limitation of nutrients, such as oxygen, during in vitro culture are of major concern and will have implications for proper bioreactor design. We recently demonstrated that oxygen gradients are indeed present within tissue engineered cartilaginous constructs. Interestingly, oxygen, besides being an essential nutrient, is also a controlling agent of developmental processes including cartilage formation. However, the specific role of oxygen in these processes is still obscure despite the recent advances in the field. In particular, the outcome of published investigations is inconsistent regarding the effect of oxygen tension on chondrocytes. Therefore, this article describes the possible roles of oxygen gradients during embryonic cartilage development and reviews the data reported on the effect of oxygen tension on in vitro chondrocyte proliferation and differentiation from a tissue engineering perspective. Furthermore, possible causes for the variance in the data are discussed. Finally, recommendations are included that may reduce the variation, resulting in more reliable and comparable data.