Influence of a joining helix on the BLUF domain of the YcgF photoreceptor from Escherichia coli

BLUF-domain-comprising photoreceptors sense blue light by utilizing FAD as a chromophore. The ycgF gene product of Escherichia coli is composed of a N-terminal BLUF domain and a C-terminal EAL domain, with the latter postulated to catalyze c-di-GMP hydrolysis. The linkage between these two domains involves a predominantly helical segment. Its role on the function of the YcgF photoreceptor domain was examined by characterizing BLUF domains with and without this segment and reconstituting them with either FAD, FMN or riboflavin. The stability of the light-adapted state of the YcgF BLUF domain depends on the presence of this joining, helical segment and the adenosine diphosphate moiety of FAD. In contrast to other BLUF domains, two-dimensional (1)H,(15)N and one-dimensional (1)H NMR spectra of isotope-labeled YcgF-(1-137) revealed large conformational changes during reversion from the light- to the dark-adapted state. Based on these results the function of the joining helix in YcgF during signal transfer and the role of the BLUF domain in regulating c-di-GMP levels is discussed.     

Distinguishing anxiety and depression: Reexamination of the reconstructed Hamilton scales.

The discriminant validities of the original and the reconstructed Hamilton anxiety and depression scales (J. H. Riskind et al, 1987) were compared in patients who had principal Diagnostic and Statistical Manual of Mental Disorders-III—Revised (DSM-III—R) anxiety disorders with or without 1 or more comorbid mood disorders. The reconstructed anxiety and depression scales had better discriminant validity (scale intercorrelation?=?.61) than the original scales did (r?=?.78). However, the reconstructed scales shared considerable variance (about 37%), which was significantly higher than the shared variance (about 2%) reported by Riskind et al. Discriminant analyses showed that the reconstructed scales did not distinguish anxiety patients with comorbid mood disorders from those without comorbid mood disorders better than the original scales did. However, the reconstructed scales eliminate item overlap, an obvious source of artifactual correlations between scores on the Hamilton anxiety and depression scales. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A computational approach to modeling commodity markets

We build an agent based computational framework to study large commodity markets. A detailed representation of the consumers, producers and the market is used to study the micro level behavior of the market and its participants. The user can control players’ preferences, their strategies, assumptions of the model, its initial conditions, market elements and trading mechanisms. The first part of the paper describes the computational framework and its three main modules. The later part describes a case study that examines the decentralized market in detail, specifically the computational options available for matching the buyers and suppliers in a synthetic market. The study illustrates the sensitivity of the outcome of various economic variables, such as clearing price, quantity, profits and social welfare, to different matching schemes in a bilateral computational setting. Based on seven different matching orders for the buyers and suppliers, our study shows that the results can vary dramatically for different pairing orders.     

Development of sex-differentiated preferences during late childhood and adolescence.

Examined factors influencing sex-differentiated responses to selected interests and interpersonal traits by young people in 3 age groups: 516 in late childhood (Grades 4–6), 398 in early adolescence (Grades 7–9), and 337 in late adolescence (Grades 10–12). There was limited evidence for same-sex bias during late childhood, varying by sex and race in its pervasiveness or clarity. Interpersonal traits were not generally sex stereotyped. Several interests were sex stereotyped during adolescence, but not those most directly related to academic learning. In general, interests were more strongly sex stereotyped by boys than by girls. Greater cognitive maturity generally attenuated sex stereotyping of interests. Certain developmental trends differed by sex and/or by race, and socioeconomic background (parents" education) influenced developmental trends among Blacks but not among Whites. (37 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modifying the adsorption behavior of polyamidoamine dendrimers at silica surfaces investigated by total internal reflection fluorescence correlation spectroscopy

Polyamidoamine (PAMAM) dendrimers were modified and tested for use as solution-phase diffusion probes in silica nanostructures. In order for the successful application of dendrimers as solution-phase probes, their interactions with silica surfaces must be understood and controlled, so that the motion of the probe is not influenced by adsorption. Adsorption/desorption kinetics of PAMAM dendrimers and their diffusion in solution near silica surfaces were investigated with total internal reflection fluorescence correlation spectroscopy (TIR-FCS). Dendrimers of generations 3, 5, and 7 were dye-labeled with carboxyrhodamine 6G. Because PAMAM dendrimers are positively charged in solution (having primary amines as end groups), significant adsorption of these molecules to the negatively charged silica surface was observed. Adsorption/desorption rates and the equilibrium constant for adsorption were determined by fitting the autocorrelation functions to a kinetic model. The desorption rate decreases and the absorption equilibrium constant increases with higher dendrimer generation. To reduce the adsorption of these probes to silica surfaces, the labeled dendrimers were reacted with succinic anhydride, converting the primary amine end groups to negatively charged carboxylic acid groups. These carboxylated dendrimers did not detectably adsorb to silica from aqueous solution. TIR-FCS was used to determine their free-solution diffusion constants near silica surfaces, and the corresponding hydrodynamic radii compare favorably with values reported from forced Rayleigh scattering measurements.     

Effect of soluble fiber on the physicochemical properties of cactus pear (Opuntia ficus indica) encapsulated using spray drying

The effects of red cactus pear encapsulation using spray drying with soluble fiber were evaluated. Cactus pear juice was mixed with 15, 22.5, or 30% soluble fiber and dried at 160, 180, or 200°C. Juice showed high levels of polyphenols, quercetin, kaempferol, isoharmetin, betacyanins, betaxanthins, and a high antioxidant activity. Increased soluble fiber amounts significantly (p<0.05) increased the pH, aw, water solubility index (WSI), L*, and b* values. Levels of polyphenols and betacyanins decreased significantly (p<0.05) as the soluble fiber content and the drying temperature increased, respectively. Encapsulation at 160°C and 22.5% of soluble fiber yielded good physical properties and high bioactive compounds. Microscopic analysis showed spherically shaped capsules, the shape was affected by the concentration of added soluble fiber. Low soluble fiber concentrations were associated with more collapsed capsules. Soluble fiber for encapsulating cactus pear resulted in a powder with good properties that can be used as a food ingredient.     

Wheat bread enrichment with hard-to-cook bean extruded flours: nutritional and acceptance evaluation

This study describes the enrichment of wheat bread with hard-to-cook black bean (BBEF) and cowpea (CEF) extruded flours. Breads containing 10% BBEF and 10% CEF presented increase of, respectively, 9% and 10% in protein content. In addition the fiber content was 2.6 higher in 10% BBEF bread and 2.2 higher in 10% CEF bread in comparison with standard bread. Despite protein and fiber increasing, the energetic value of substituted breads remained unchanged. An increase in the substitution to 15% resulted in decrease of specific volume and density of the breads. Results of sensory analysis to 10% BBEF bread presented overall appearance scores higher than standard bread and overall flavor acceptance very similar to standard. A total of 10% CEF bread presented similar appearance to those standard bread and 73% overall flavor acceptance. It is interesting to point out that distribution of 10% CEF bread overall flavor scores showed 3 distinct levels of consumer's sensibility. Practical Application: Breads enriched with extruded bean flours presented fiber and protein content improved and a very good consumer's acceptance. These results indicate that extruded bean flours constitute ingredients nutritionally and economically viable for technological application in breads elaboration, conferring improvement of nutritional characteristics without changing sensory attributes.     

Influence of sterilization methods on cell behavior and functionality of osteoblasts cultured on TiO2 nanotubes

We investigated the adhesion, proliferation and osteogenic functionality of osteoblasts cultured on titanium dioxide (TiO₂) nanotubes in response to different sterilization methods (dry autoclaving vs. wet autoclaving). We prepared various sizes (30–100 nm diameter) of TiO₂ nanotubes on titanium substrates by anodization, sterilized nanotubes by different conditions, and seeded osteoblast cells onto the nanotube surfaces with two different cell seeding densities (10,000 vs. 50,000 cells/well in 12-culture well). The result of this study indicates that the adhesion, proliferation and alkaline phosphatase activity of osteoblasts cultured on only the larger 70 and 100 nm TiO₂ nanotube arrays were dramatically changed by the different sterilization conditions at a low cell seeding density. However, with a higher cell seeding density (50,000 cells/well in 12-cell culture well), the results revealed no significant difference among altered nanotube geometry, 30–100 nm diameters, nor sterilization methods. Next, it was revealed that the nanofeatures of proteins adhered on nanotubular TiO₂ morphology are altered by the sterilization method. It was determined that this protein adhesion effect, in combination with the cell density of osteoblasts seeded onto such TiO₂ nanotube surfaces, has profound effects on cell behavior. This study clearly shows that these are some of the important in vitro culture factors that need to be taken into consideration, as well as TiO₂ nanotube diameters which play an important role in the improvement of cell behavior and functionality.     

Expression of DNA Methyltransferase 3B Isoforms Is Associated with DNA Satellite 2 Hypomethylation and Clinical Prognosis in Advanced High-Grade Serous Ovarian Carcinoma

Alterations in DNA methylation are critical for the carcinogenesis of ovarian tumors, especially ovarian carcinoma (OC). DNMT3B, a de novo DNA methyltransferase (DNMT), encodes for fifteen spliced protein products or isoforms. DNMT3B isoforms lack exons for the catalytic domain, with functional consequences on catalytic activity. Abnormal expression of DNMT3B isoforms is frequently observed in several types of cancer, such as breast, lung, kidney, gastric, liver, skin, leukemia, and sarcoma. However, the expression patterns and consequences of DNMT3B isoforms in OC are unknown. In this study, we analyzed each DNMT and DNMT3B isoforms expression by qPCR in 63 OC samples and their association with disease-free survival (DFS), overall survival (OS), and tumor progression. We included OC patients with the main histological subtypes of EOC and patients in all the disease stages and found that DNMTs were overexpressed in advanced stages (p-value < 0.05) and high-grade OC (p-value < 0.05). Remarkably, we found DNMT3B1 overexpression in advanced stages (p-value = 0.0251) and high-grade serous ovarian carcinoma (HGSOC) (p-value = 0.0313), and DNMT3B3 was overexpressed in advanced stages (p-value = 0.0098) and high-grade (p-value = 0.0004) serous ovarian carcinoma (SOC). Finally, we observed that overexpression of DNMT3B isoforms was associated with poor prognosis in OC and SOC. DNMT3B3 was also associated with FDS (p-value = 0.017) and OS (p-value = 0.038) in SOC patients. In addition, the ovarian carcinoma cell lines OVCAR3 and SKOV3 also overexpress DNMT3B3. Interestingly, exogenous overexpression of DNMT3B3 in OVCAR3 causes demethylation of satellite 2 sequences in the pericentromeric region. In summary, our results suggest that DNMT3B3 expression is altered in OC.