Novel Bacterial Production of Two Different Bioactive Forms of Human Stem-Cell Factor

Human stem-cell factor (hSCF) stimulates the survival, proliferation, and differentiation of hematopoietic cells by binding to the c-Kit receptor. Various applications of hSCF require the efficient and reliable production of hSCF. hSCF exists in three forms: as two membrane-spanning proteins hSCF248 and hSCF229 and truncated soluble N-terminal protein hSCF164. hSCF164 is known to be insoluble when expressed in Escherichia coli cytoplasm, requiring a complex refolding procedure. The activity of hSCF248 has never been studied. Here, we investigated novel production methods for recombinant hSCF164 and hSCF248 without the refolding process. To increase the solubility of hSCF164, maltose-binding protein (MBP) and protein disulfide isomerase b’a’ domain (PDIb’a’) tags were attached to the N-terminus of hSCF164. These fusion proteins were overexpressed in soluble form in the Origami 2(DE3) E. coli strain. These solubilization effects were enhanced at a low temperature. His-hSCF248, the poly-His tagged form of hSCF248, was expressed in a highly soluble form without a solubilization tag protein, which was unexpected because His-hSCF248 contains a transmembrane domain. hSCF164 was purified using affinity and ion-exchange chromatography, and His-hSCF248 was purified by ion-exchange and gel filtration chromatography. The purified proteins stimulated the proliferation of TF-1 cells. Interestingly, the EC₅₀ value of His-hSCF248 was 1 pg/mL, 100-fold lower than 9 ng/mL hSCF164. Additionally, His-hSCF248 decreased the doubling time, increased the proportion of S and G2/M stages in the cell cycle, and increased the c-Myc expression at a 1000-fold lower concentration than hSCF164. In conclusion, His-hSCF248 was expressed in a soluble form in E. coli and had stronger activity than hSCF164. The molecular chaperone, MBP, enabled the soluble overexpression of hSCF164.     

Winery grape-residue extract: Effects on quality and sensory attributes of cooked chicken meat

Sensory analysis, instrumental color, pH, and thiobarbituric acid reactive substances (TBARS) were determined on cooked chicken meat with and without grape seed extract during refrigerated storage. The effectiveness of extracts of winery grape residue from the grape varieties ‘Isabel’ and ‘Niagara’ were tested to evaluate their effectiveness at delaying lipid oxidation in cooked chicken meat and stored under refrigeration (4±1°C). The samples were aerobically and vacuum packaged and stored for 14 days. ‘Isabel’ grape extract (IGE) and ‘Niagara’ grape extract (NGE) proved effective at promoting oxidative stability when applied at concentrations of 40 or 60 mg of gallic acid equivalents (GAE)/kg, with results similar to the synthetic antioxidant butylated hydroxytoluene (BHT). The antioxidant efficiency of the extracts was highly dependent on the concentration used. The addition of grape-residue extracts combined with vacuum packaging proved to be a good method for increasing lipid stability in cooked chicken meat stored under refrigeration.     

Mental health services in Louisiana school-based health centers post-Hurricanes Katrina and Rita.

Following Hurricanes Katrina and Rita, Louisiana school-based health centers (SBHCs) were called on to respond to a sharp increase in mental health needs, especially for displaced students coping with grief, loss, trauma, and uncertainty. To assess the impact of the hurricanes on the students and the needs of SBHC mental health providers (MHPs), we surveyed MHPs in each of the SBHCs under the auspices of the Louisiana Department of Health and Hospitals, Office of Public Health. SBHC practitioners from around the state reported that mental health service utilization rose during the 2005-2006 school year, but utilization of services increased most significantly in schools receiving the majority of displaced students. Anxiety and adjustment problems were noted as increasing the most following the hurricanes. A multitude of other conditions was also reported. By the time of this survey in April 2006, the reported prevalence of most symptoms had declined, but all remained above their pre-hurricane levels. Self-reported needs of SBHC MHPs are also discussed in light of the major natural disasters. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Decision style in depression: The contribution of perceived risks versus benefits.

The present study investigated the contribution of cognitive and social factors to the decision style of depressed persons. During two sessions (Times 1 and 2), depressed and nondepressed college students were asked to imagine themselves making decisions about common life situations that afforded potential benefits but that also entailed potential risks. The decision scenarios varied in content. For each situation, subjects evaluated several potential risks and benefits and indicated what decisions they would make. In both sessions and for all types of decision scenarios, the depressed assigned greater weight to risks than did the nondepressed. Furthermore, for decisions about initiating social contact and establishing intimacy, the depressed expressed a greater reluctance to take the target action than did the nondepressed, and their perceptions of risks appeared to influence their estimated decisions more strongly. The Time 2 study also revealed that most of these differences applied equally when individuals were thinking about themselves or another person. However, risk perceptions were found to contribute more to the decision style of the depressed, relative to the nondepressed, only when their thoughts were focused on themselves and not when their thoughts were focused on another person. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synthesis and structural characteristics of highly graphitized carbon nanofibers produced from the catalytic decomposition of ethylene: Influence of the active metal (Co, Ni, Fe) and the zeolite type support

In order to study the influence of the metal phase in the carbon yield and structural characteristics of carbon nanofibers (CNFs) synthesized by CVD over supported catalysts, different catalysts were prepared using iron, cobalt and nickel as active metal and zeolites Y and mordenite as support. The results showed that the metal precursor produced a great influence on the catalytic activity, fact that could be explained in according to the different solubility of carbon in the metals or in the differences in the diffusion and segregation of carbon through the metal particles. Characterization data of the solid carbon products revealed unique structures and textural properties as well as crystalline conditions on function of metal used. Additionally, support-metal interaction was evaluated, where experiments with similar nickel load over Y and mordenite zeolites were carried out, finding higher carbon yields and more ordered structures when Y zeolite was used.     

Organic acids composition of Cydonia oblonga Miller leaf

Organic acid profiles of 36 Cydonia oblonga Miller leaf samples, from three different geographical origins of northern (Bragança and Carrazeda de Ansiães) and central Portugal (Covilhã), harvested in three collection months (June, August and October of 2006), were determined by HPLC/UV (214 nm). Quince leaves presented a common organic acid profile, composed of six constituents: oxalic, citric, malic, quinic, shikimic and fumaric acids. C. oblonga leaves total organic acid content varied from 1.6 to 25.8 g/kg dry matter (mean value of 10.5 g/kg dry matter). Quinic acid was the major compound (72.2%), followed by citric acid (13.6%).     

Mating behavior of the golden-orb-weaving spider, Nephila clavipes: I. Female receptivity and male courtship.

Observed 112 marked, free-moving female golden-orb-weaving spiders and the 161 males inhabiting their webs to determine factors that influence the likelihood of female sexual receptivity. Females were observed mating during a 2-day period after the final molt and later in adulthood when they fed. Results show that copulation differed at these times, with the most clearly defined and prolonged matings occurring during the 2-day period after the final molt. Juvenile females copulated only a few times for a few seconds. Various explanations for multiple matings are discussed, and it is suggested that females are situationally receptive throughout their adulthood because they cannot be assured that males will be present during the final molt period. Juvenile and adult females preyed on males but did so infrequently. Several of the instances of predation occurred within a few days after the final molt, suggesting that predation is caused by male persistence in attempting to copulate. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synthesis and rheological properties of an associative star polymer in aqueous solutions

Rheological properties of aqueous solutions and hydrogels formed by an amphiphilic star block copolymer, poly(acrylic acid)-block-polystyrene (PAA₅₄-b-PS₆)₄, were investigated as a function of the polymer concentration (C_p), temperature, and added salt concentration. The water-soluble polymer synthesised by atom transfer radical polymerization (ATRP) was found to form hydrogels at room temperature at polymer concentrations, C_p, over 22 g/L due to the interpolymer hydrophobic association of the PS blocks. Increasing C_p leads to stronger elastic networks at room temperature that show a gel-to-solution transition with increasing temperature. Increase of ionic strength decreases the moduli compared with the pure hydrogel but did not affect the gel-sol transition temperature significantly. Small-angle X-ray experiments showed two distinct scattering correlation peaks for samples above the gelling C_p, which indicates the aggregates formed due to hydrophobic association. Upon heating the intensity of the scattering correlation peaks was found to decrease indicating the loss of the network structure due to thermal motion.