The Nicastrin ectodomain adopts a highly thermostable structure

Nicastrin is a type I transmembrane glycoprotein, which is part of the high molecular weight gamma-secretase complex. gamma-Secretase is one of the key players associated with the generation of Alzheimer's disease pathology, since it liberates the neurotoxic amyloid beta-peptide. Four proteins Nicastrin, anterior pharynx-defective-1 (Aph-1), presenilin enhancer-2 (Pen-2) and Presenilin are essential to form the active gamma-secretase complex. Recently it has been shown, that Nicastrin has a key function in stabilizing the mature gamma-secretase complex and may also be involved in substrate recognition. So far no structural data for the Nicastrin ectodomain or any other gamma-secretase component are available. We therefore used Circular Dichroism (CD) spectroscopy to demonstrate that Nicastrin, similar to its homologues, the Streptomyces griseus aminopeptidase (SGAP) and the transferrin receptor (TfR), adopts a thermostable secondary structure. Furthermore, the Nicastrin ectodomain has an exceptionally high propensity to refold after thermal denaturation. These findings provide evidence to further support the hypothesis that Nicastrin may share evolutionary conserved properties with the aminopeptidase and the transferrin receptor family

Ein Plädoyer für Dienstleistungspolitik: Analysen, Strategien und Beispiele für Beschäftigung durch Innovation im Tertiären Sektor

Die Autoren versuchen zu begründen, warum zur Realisierung der Potentiale des Dienstleistungssektors politischer Handlungsbedarf besteht und Ziele einer Handlungsstrategie und das zu ihrer Umsetzung erforderliche Instrumentarium zu entwickeln. Dies erfolgt in einem ersten Schritt für den Dienstleistungsbereich insgesamt und in einem zweiten Schritt exemplarisch für eine Dienstleistungsbranche - und zwar für die Versicherungswirtschaft. Die Versicherungswirtschaft steht aus verschiedenen Gründen vor Strukturbrüchen und weist darum wie gezeigt wird - einen spezifischen Handlungsbedarf auf. (IAB2

Monozygotic twins discordant for constitutive BRCA1 promoter methylation, childhood cancer and secondary cancer

We describe monozygotic twins discordant for childhood leukemia and secondary thyroid carcinoma. We used bisulfite pyrosequencing to compare the constitutive promoter methylation of BRCA1 and several other tumor suppressor genes in primary fibroblasts. The affected twin displayed an increased BRCA1 methylation (12%), compared with her sister (3%). Subsequent bisulfite plasmid sequencing demonstrated that 13% (6 of 47) BRCA1 alleles were fully methylated in the affected twin, whereas her sister displayed only single CpG errors without functional implications. This between-twin methylation difference was also found in irradiated fibroblasts and untreated saliva cells. The BRCA1 epimutation may have originated by an early somatic event in the affected twin: approximately 25% of her body cells derived from different embryonic cell lineages carry one epigenetically inactivated BRCA1 allele. This epimutation was associated with reduced basal protein levels and a higher induction of BRCA1 after DNA damage. In addition, we performed a genome-wide microarray analysis of both sisters and found several copy number variations, i.e., heterozygous deletion and reduced expression of the RSPO3 gene in the affected twin. This monozygotic twin pair represents an impressive example of epigenetic somatic mosaicism, suggesting a role for constitutive epimutations, maybe along with de novo genetic alterations in recurrent tumor development

Early Influences of Nutrition on Postnatal Growth

Health and nutrition modulate postnatal growth. The availability ofamino acids and energy, and insulin and insulin-like growth factor-I(IGF-I) regulates early growth through the mTOR pathway. Amino acids andglucose also stimulate the secretion of IGF-I and insulin. Postnatalgrowth induces lasting, programming effects on later body size andadiposity in animals and in human observational studies. Rapid weightgain in infancy and the first 2 years was shown to predict increasedobesity risk in childhood and adulthood. Breastfeeding leads to lesserhigh weight gain in infancy and reduces obesity risk in later life byabout 20%, presumably partly due to the lower protein supply with humanmilk than conventional infant formula. In a large randomized clinicaltrial, we tested the hypothesis that reduced infant formula proteincontents lower insulin-releasing amino acid concentrations and therebydecrease circulating insulin and IGF-I levels, resulting in lesser earlyweight gain and reduced later obesity risk (the ‘Early ProteinHypothesis’). The results demonstrate that lowered protein in infantformula induces similar - but not equal - metabolic and endocrineresponses and normalizes weight and BMI relative to breastfed controlsat the age of 2 years. The results available should lead to enhancedefforts to actively promote, protect and support breastfeeding. Forinfants that are not breastfed or not fully breastfed, the use of infantformulas with lower protein contents but high protein quality appearspreferable. Cows’ milk as a drink provides high protein intake andshould be avoided in infancy

Early Influences of Nutrition on Postnatal Growth

Health and nutrition modulate postnatal growth. The availability ofamino acids and energy, and insulin and insulin-like growth factor-I(IGF-I) regulates early growth through the mTOR pathway. Amino acids andglucose also stimulate the secretion of IGF-I and insulin. Postnatalgrowth induces lasting, programming effects on later body size andadiposity in animals and in human observational studies. Rapid weightgain in infancy and the first 2 years was shown to predict increasedobesity risk in childhood and adulthood. Breastfeeding leads to lesserhigh weight gain in infancy and reduces obesity risk in later life byabout 20%, presumably partly due to the lower protein supply with humanmilk than conventional infant formula. In a large randomized clinicaltrial, we tested the hypothesis that reduced infant formula proteincontents lower insulin-releasing amino acid concentrations and therebydecrease circulating insulin and IGF-I levels, resulting in lesser earlyweight gain and reduced later obesity risk (the ‘Early ProteinHypothesis’). The results demonstrate that lowered protein in infantformula induces similar - but not equal - metabolic and endocrineresponses and normalizes weight and BMI relative to breastfed controlsat the age of 2 years. The results available should lead to enhancedefforts to actively promote, protect and support breastfeeding. Forinfants that are not breastfed or not fully breastfed, the use of infantformulas with lower protein contents but high protein quality appearspreferable. Cows’ milk as a drink provides high protein intake andshould be avoided in infancy

Matrix-isolation FTIR study of azidoacetone and azidoacetonitrile

Azidoacetonitrile (N₃CH₂CN) and azidoacetone (N₃CH₂COCH₃) were studied by matrix-isolation FTIR spectroscopy in solid neon, argon and nitrogen. The IR spectra calculated using the density fuctional theoretical method are discussed in comparison with the experimental data. Significant broadening of the recorded azide bands indicate an awkward fit of these compounds into the solid environment. The strongest absorption is observed for both compounds in the regions of asymmetric and symmetric stretches of the N₃ azide group. Strong band splittings in the N₃ asymmetric stretch region can be most likely explained by very strong Fermi resonances with the CN stretch and combinations and overtones of the numerous lower frequency vibrational modes

Real-Time Cytotoxicity Assay for Rapid and Sensitive Detection of Ricin from Complex Matrices

BACKGROUND: In the context of a potential bioterrorist attack sensitive and fast detection of functionally active toxins such as ricin from complex matrices is necessary to be able to start timely countermeasures. One of the functional detection methods currently available for ricin is the endpoint cytotoxicity assay, which suffers from a number of technical deficits. METHODOLOGY/FINDINGS: This work describes a novel online cytotoxicity assay for the detection of active ricin and Ricinus communis agglutinin, that is based on a real-time cell electronic sensing system and impedance measurement. Characteristic growth parameters of Vero cells were monitored online and used as standardized viability control. Upon incubation with toxin the cell status and the cytotoxic effect were visualized using a characteristic cell index-time profile. For ricin, tested in concentrations of 0.06 ng/mL or above, a concentration-dependent decrease of cell index correlating with cytotoxicity was recorded between 3.5 h and 60 h. For ricin, sensitive detection was determined after 24 h, with an IC50 of 0.4 ng/mL (for agglutinin, an IC50 of 30 ng/mL was observed). Using functionally blocking antibodies, the specificity for ricin and agglutinin was shown. For detection from complex matrices, ricin was spiked into several food matrices, and an IC50 ranging from 5.6 to 200 ng/mL was observed. Additionally, the assay proved to be useful in detecting active ricin in environmental sample materials, as shown for organic fertilizer containing R. communis material. CONCLUSIONS/SIGNIFICANCE: The cell-electrode impedance measurement provides a sensitive online detection method for biologically active cytotoxins such as ricin. As the cell status is monitored online, the assay can be standardized more efficiently than previous approaches based on endpoint measurement. More importantly, the real-time cytotoxicity assay provides a fast and easy tool to detect active ricin in complex sample matrices

Estrogen Receptor β-Selective Agonists Stimulate Calcium Oscillations in Human and Mouse Embryonic Stem Cell-Derived Neurons

Estrogens are used extensively to treat hot flashes in menopausal women. Some of the beneficial effects of estrogens in hormone therapy on the brain might be due to nongenomic effects in neurons such as the rapid stimulation of calcium oscillations. Most studies have examined the nongenomic effects of estrogen receptors (ER) in primary neurons or brain slices from the rodent brain. However, these cells can not be maintained continuously in culture because neurons are post-mitotic. Neurons derived from embryonic stem cells could be a potential continuous, cell-based model to study nongenomic actions of estrogens in neurons if they are responsive to estrogens after differentiation. In this study ER-subtype specific estrogens were used to examine the role of ERα and ERβ on calcium oscillations in neurons derived from human (hES) and mouse embryonic stem cells. Unlike the undifferentiated hES cells the differentiated cells expressed neuronal markers, ERβ, but not ERα. The non-selective ER agonist 17β-estradiol (E2) rapidly increased [Ca2+]i oscillations and synchronizations within a few minutes. No change in calcium oscillations was observed with the selective ERα agonist 4,4′,4″-(4-Propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol (PPT). In contrast, the selective ERβ agonists, 2,3-bis(4-Hydroxyphenyl)-propionitrile (DPN), MF101, and 2-(3-fluoro-4-hydroxyphenyl)-7-vinyl-1,3 benzoxazol-5-ol (ERB-041; WAY-202041) stimulated calcium oscillations similar to E2. The ERβ agonists also increased calcium oscillations and phosphorylated PKC, AKT and ERK1/2 in neurons derived from mouse ES cells, which was inhibited by nifedipine demonstrating that ERβ activates L-type voltage gated calcium channels to regulate neuronal activity. Our results demonstrate that ERβ signaling regulates nongenomic pathways in neurons derived from ES cells, and suggest that these cells might be useful to study the nongenomic mechanisms of estrogenic compounds

Determination of nutrient salts by automatic methods both in seawater and brackish water: the phosphate blank

9 páginas, 2 tablas, 2 figurasThe main inconvenience in determining nutrients in seawater by automatic methods is simply solved: the preparation of a suitable blank which corrects the effect of the refractive index change on the recorded signal. Two procedures are proposed, one physical (a simple equation to estimate the effect) and the other chemical (removal of the dissolved phosphorus with ferric hydroxide).Support for this work came from CICYT (MAR88-0245 project) and Conselleria de Pesca de la Xunta de GaliciaPeer reviewe