Highly Stable Plasmonic Nanostructures on a Nickel-Sputtered Glass and Polymeric Optical Fiber Sensors

Plasmonics - This study shows development of highly sensitive and stable localized surface plasmon resonance (LSPR)-active U-bent glass and polymeric optical fiber (GOF and POF) sensor probes by a...     

Trophic control of lung development by sympathetic neurons: effects of neonatal sympathectomy with 6-hydroxydopamine

The onset of peripheral sympathetic neuronal function is thought to provide trophic regulatory signals for development of adrenergic target tissues. In the current study, we examined the effects on lung development of neonatal sympathectomy with 6-hydroxydopamine. The completeness of the lesion and effectiveness in reducing sympathetic input to the tissue were confirmed by direct measurement of norepinephrine levels and turnover. Despite the denervation, no evidence of beta-receptor up-regulation was found; in fact, receptor binding sites tended to be reduced throughout development. The cyclic AMP response to isoproterenol challenge was initially suppressed in the lesioned animals, but became supersensitive even in the face of reduced receptor binding capabilities. Evidence was also obtained for ontogenetic abnormalities in the ornithine decarboxylase/polyamine system, which is partially controlled by beta-adrenergic input and which regulates macromolecule synthesis in replicating and differentiating cells. Eventually, the alterations were reflected in aberrant developmental patterns of DNA, RNA and protein in the lung. These results indicate that sympathetic neurons influence the biochemical development of the lung and may serve to program permanently the relationships among receptor sites, receptor coupling to cellular function, and control of cell maturation.     

Improving consensus structure by eliminating averaging artifacts

Background  

Common structural biology methods (i.e., NMR and molecular dynamics) often produce ensembles of molecular structures. Consequently, averaging of 3D coordinates of molecular structures (proteins and RNA) is a frequent approach to obtain a consensus structure that is representative of the ensemble. However, when the structures are averaged, artifacts can result in unrealistic local geometries, including unphysical bond lengths and angles.     

Differentiation of Gram-Negative Bacterial Aerosol Exposure Using Detected Markers in Bronchial-Alveolar Lavage Fluid

The identification of biosignatures of aerosol exposure to pathogens has the potential to provide useful diagnostic information. In particular, markers of exposure to different types of respiratory pathogens may yield diverse sets of markers that can be used to differentiate exposure. We examine a mouse model of aerosol exposure to known Gram negative bacterial pathogens, Francisella tularensis novicida and Pseudomonas aeruginosa. Mice were subjected to either a pathogen or control exposure and bronchial alveolar lavage fluid (BALF) was collected at four and twenty four hours post exposure. Small protein and peptide markers within the BALF were detected by matrix assisted laser desorption/ionization (MALDI) mass spectrometry (MS) and analyzed using both exploratory and predictive data analysis methods; principle component analysis and degree of association. The markers detected were successfully used to accurately identify the four hour exposed samples from the control samples. This report demonstrates the potential for small protein and peptide marker profiles to identify aerosol exposure in a short post-exposure time frame.     

The effect of growth medium on B. anthracis Sterne spore carbohydrate content

The expressed characteristics of biothreat agents may be impacted by variations in the culture environment, including growth medium formulation. The carbohydrate composition of B. anthracis spores has been well studied, particularly for the exosporium, which is the outermost spore structure. The carbohydrate composition of the exosporium has been demonstrated to be distinct from the vegetative form containing unique monosaccharides. We have investigated the carbohydrate composition of B. anthracis Sterne spores produced using four different medium types formulated with different sources of medium components. The amount of rhamnose, 3-O-methyl rhamnose and galactosamine was found to vary significantly between spores cultured using different medium formulations. The relative abundance of these monosaccharides compared to other monosaccharides such as mannosamine was also found to vary with medium type. Specific medium components were also found to impact the carbohydrate profile. Xylose has not been previously described in B. anthracis spores but was detected at low levels in two media. This may represent residual material from the brewery yeast extract used to formulate these two media. These results illustrate the utility of this method to capture the impact of growth medium on carbohydrate variation in spores. Detecting carbohydrate profiles in B. anthracis evidentiary material may provide useful forensic information on the growth medium used for sporulation.     

Repeated maternal separation in the neonatal rat: cellular mechanisms contributing to brain growth sparing.

Separation of neonates from their dam has been shown to evoke acutely a variety of biochemical responses, typified by depression of ornithine decarboxylase (ODC) activity. In the current study where rat pups were removed from their nursing dams for 6 h, ODC activities in the liver, heart, kidney and lung were markedly suppressed, but the enzyme in the brain was not altered during the early postnatal ages. These data suggest that the brain was protected from maternal separation insults, a homeostatic response mediated in part, by an increase of circulating corticosterone and glycogen mobilization from peripheral tissues, particularly the liver. In addition, we examined whether these responses were extended to pups who were subject to repeated episodes of maternal deprivation, and whether this stress paradigm might be associated with corresponding changes of cellular growth and maturation. Pups were removed from their dams for 6 h daily beginning at 4 days of age until weaning at 21 days. Plasma corticosterone levels of the deprived pups were elevated significantly at the end of each stress episode but returned to basal (control) levels subsequently. The repeating stress paradigm did not influence the magnitude of this hormonal response at the ensuing ages. Consistent with findings observed in the single episodes of stress, ODC activities in the peripheral tissues were significantly depressed in pups subject to repeated maternal deprivation, but the enzyme appeared to recover to control levels 18 h after each insult. In contrast, brain ODC activity did not exhibit any change throughout the period examined. Moreover, while ontogenetic gains of DNA and protein in the peripheral tissues of the deprived rats lagged slightly but consistently behind those of controls, these macromolecules in the brain were not affected appreciably. These results thus suggest that brain growth was, by and large, spared from insults associated with repeated maternal separation; but this stressful paradigm did produce marked, though reversible biochemical and physiological responses in the peripheral tissues of neonates, which cumulatively led to a lag of cellular development.     

A microfluidic competitive immuno-aggregation assay for high sensitivity cell secretome detection

We report a high-sensitivity cell secretome detection method using competitive immuno-aggregation and a micro-Coulter counter. A target cell secretome protein competes with anti-biotin-coated microparticles (MPs) to bind with a biotinylated antibody (Ab), causing decreased aggregation of the functionalized MPs and formation of a mixture of MPs and aggregates. In comparison, without the target cell secretome protein, more microparticles are functionalized, and more aggregates are formed. Thus, a decrease in the average volume of functionalized microparticles/aggregates indicates an increase in cell secretome concentration. This volume change is measured by the micro-Coulter counter, which is used to quantitatively estimate the cell secretome concentration. Vascular endothelial growth factor (VEGF), one of the key cell secretome proteins that regulate angiogenesis and vascular permeabilization, was used as the target protein to demonstrate the sensing principle. A standard calibration curve was generated by testing samples with various VEGF concentrations. A detection range from 0.01 ng/mL to 100.00 ng/mL was achieved. We further demonstrated the quantification of VEGF concentration in exogenous samples collected from the secretome of human mesenchymal stem cells (hMSCs) at different incubation times. The results from the assay agree well with the results of a parallel enzyme-linked immunoabsorbent assay (ELISA) test, indicating the specificity and reliability of the competitive immuno-aggregation assay. With its simple structure and easy sample preparation, this assay not only enables high sensitivity detection of VEGF but also can be readily extended to other types of cell secretome analysis as long as the specific Ab is known.     

Dimensions of global population projections: what do we know about future population trends and structures?

The total size of the world population is likely to increase from its current 7 billion to 8–10 billion by 2050. This uncertainty is because of unknown future fertility and mortality trends in different parts of the world. But the young age structure of the population and the fact that in much of Africa and Western Asia, fertility is still very high makes an increase by at least one more billion almost certain. Virtually, all the increase will happen in the developing world. For the second half of the century, population stabilization and the onset of a decline are likely. In addition to the future size of the population, its distribution by age, sex, level of educational attainment and place of residence are of specific importance for studying future food security. The paper provides a detailed discussion of different relevant dimensions in population projections and an evaluation of the methods and assumptions used in current global population projections and in particular those produced by the United Nations and by IIASA.