Novel Redox-Dependent Esterase Activity (EC 3.1.1.2) for DJ-1: Implications for Parkinson’s Disease

Mutations the in human DJ-1 (hDJ-1) gene are associated with early-onset autosomal recessive forms of Parkinson’s disease (PD). hDJ-1/parkinsonism associated deglycase (PARK7) is a cytoprotective multi-functional protein that contains a conserved cysteine-protease domain. Given that cysteine-proteases can act on both amide and ester substrates, we surmised that hDJ-1 possessed cysteine-mediated esterase activity. To test this hypothesis, hDJ-1 was overexpressed, purified and tested for activity towards 4-nitrophenyl acetate (pNPA) as µmol of pNPA hydrolyzed/min/mg·protein (U/mg protein). hDJ-1 showed maximum reaction velocity esterase activity (V_max = 235.10 ± 12.00 U/mg protein), with a sigmoidal fit (S_0.5 = 0.55 ± 0.040 mM) and apparent positive cooperativity (Hill coefficient of 2.05 ± 0.28). A PD-associated mutant of DJ-1 (M26I) lacked activity. Unlike its protease activity which is inactivated by reactive oxygen species (ROS), esterase activity of hDJ-1 is enhanced upon exposure to low concentrations of hydrogen peroxide (<10 µM) and plateaus at elevated concentrations (>100 µM) suggesting that its activity is resistant to oxidative stress. Esterase activity of DJ-1 requires oxidation of catalytic cysteines, as chemically protecting cysteines blocked its activity whereas an oxido-mimetic mutant of DJ-1 (C106D) exhibited robust esterase activity. Molecular docking studies suggest that C106 and L126 within its catalytic site interact with esterase substrates. Overall, our data show that hDJ-1 contains intrinsic redox-sensitive esterase activity that is abolished in a PD-associated mutant form of the hDJ-1 protein.     

Molecular weight (M n) and functionality effects on CUP formation and stability

The formation of colloidal unimolecular polymer (CUP) particles from single polymer strands was investigated as a function of molecular weight. The CUP particle size was correlated with the absolute molecular weight and its distribution. The characteristics of the particles were evaluated with respect to viscosity, acid number, size distribution, and stability. The particle size varied from less than 3 nm to above 8 nm representing polymers with molecular weight in the range of 3000–153,000. Lower molecular weight polymers were found to be unstable. Particle size measurements using dynamic light scattering technique indicated a normal distribution which corresponded to the molecular weight distribution of the copolymer. The statistical distribution of the acid groups in the polymer chains played a significant role in the stability of low molecular weight polymers.     

Oregano: properties, composition and biological activity

The oregano spice includes various plant species. The most common are the genus Origanum, native of Europe, and the Lippia, native of Mexico. Among the species of Origanum. their most important components are the limonene, gamma-cariofilene, rho-cymenene, canfor, linalol, alpha-pinene, carvacrol and thymol. In the genus Lippia, the same compounds can be found. The oregano composition depends on the specie, climate, altitude, time of recollection and the stage of growth. Some of the properties of this plant's extracts are being currently studied due to the growing interest for substituting synthetic additives commonly found in foods. Oregano has a good antioxidant capacity and also presents antimicrobial activity against pathogenic microorganisms like Salmonella typhimurium, Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, among others. These are all characteristics of interest for the food industry because they may enhance the safety and stability of foods. There are also some reports regarding the antimutagenic and anticarcinogenic effect of oregano; representing an alternative for the potential treatment and/or prevention of certain chronic ailments, like cancer.     

Missing information in spoken word recognition: Nonrelased stop consonants.

Cross-modal semantic priming and phoneme monitoring experiments investigated processing of word-final nonreleased stop consonants (e.g., kit may be pronounced /kIt/ or /kI/), which are common phonological variants in American English. Both voiced /d/ and voiceless /t/ segments were presented in release and no-release versions. A cross-modal semantic priming task (Experiment 1) showed comparable priming for /d/ and /t/ versions. A second set of stimuli ending in /s/ were presented as intact, missing /s/, or with a mismatching final segment and showed significant but reduced priming for the latter two conditions. Experiment 2 showed that phoneme monitoring reaction time for release and no-release words and onset mismatching stimuli (derived pseudowords) increased as acoustic-phonetic similarity to the intended word decreased. The results suggest that spoken word recognition does not require special mechanisms for processing no-release variants. Rather, the results can be accounted for by means of existing assumptions concerning probabilistic activation that is based on partial activation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Colloidal Processing of Glass–Ceramics for Laminated Object Manufacturing

Green tapes of Li₂O–ZrO₂–SiO₂–Al₂O₃ (LZSA) parent glass were produced by aqueous tape casting as the starting material for the laminated object manufacturing (LOM) process. The rheological behavior of the powder suspensions in aqueous media, as well as the mechanical properties of the cast tapes, was evaluated. According to ξ potential measurements, the LZSA glass powder particles showed acid surface characteristics and an IEP of around 4 when in aqueous media. The critical volume fraction of solids was about 72 wt% (27 vol%), which hindered the processability of more concentrated slurries. The glass particles also showed an anisometric profile, which contributed to an increase in the interactions between particles during flow. Therefore, the suspensions could not be processed at high solids loadings. Aqueous-based glass suspensions were also characterized by shear thickening after the addition of dispersants. Three slurry compositions were formulated, suitable green tapes were cast, and tapes were successfully laminated by LOM to a gear wheel geometry. A higher tensile strength of the green tapes corresponded to a higher tensile strength of the laminates. Thermal treatment was then applied to the laminates: pyrolysis at 525°C, sintering at 700°C for 1 h, and crystallization at 850°C for 30 min. A 20% volumetric shrinkage was observed, but no surface flaws or inhomogeneous areas were detected. The sintered part maintained the curved edges and internal profile after heat treatment.     

Weight suppression predicts weight gain over treatment but not treatment completion or outcome in bulimia nervosa.

The authors attempted to replicate previous findings that weight suppression is a significant predictor of treatment completion and treatment outcome (M. L. Butryn, M. R. Lowe, D. L. Safer, & W. S. Agras, 2006) and weight gain over treatment (M. R. Lowe, W. Davis, D. Lucks, R. A. Annunziato, & M. L. Butryn, 2006) among women with bulimic disorders. The authors also examined 2 alternative measures of weight variability. Participants were 132 women with bulimia nervosa treated with cognitive-behavioral therapy. Participants who dropped out of treatment did not have significantly higher levels of weight suppression than did treatment completers. Among those who completed treatment, weight suppression did not significantly predict binge eating and purging at post-treatment. Weight suppression did significantly predict weight change and, in particular, weight gain (≥5 kg) over treatment. Alternative measures of weight variability did not significantly predict treatment completion or treatment outcome, but 1 measure significantly predicted weight gain over treatment. In conclusion, the authors failed to replicate the previous finding that weight suppression predicts treatment compliance and treatment outcome, but they did replicate the finding that weight suppression predicts weight gain over treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Factor structure integrity of the Personal Attributes Questionnaire: An English–French comparison.

The Personal Attributes Questionnaire (PAQ) is one of the pre-eminent measures of gender-specific personality characteristics. To evaluate the PAQ'S viability 20 yrs after its creation, the authors assessed the dimensionality and psychometric properties of the original PAQ and a French version using samples of 637 English-speaking and French-speaking university administrators. The structure of the English form of the PAQ was supported for both women and men when the data were submitted to confirmatory analyses. Support was not as convincing for the dimensionality of the French form of the PAQ, however. Some evidence for expected differences in mean Instrumentality and Expressivity scores was found between women and men. Findings support the continued use of the English PAQ as a measure of Instrumental and Expressive personality traits. Further study of the French PAQ is recommended. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Self-evaluation of abilities: Accurate self-assessment versus biased self-enhancement.

In Study 1, 170 volunteers (mean age 24.2 yrs) chose among 8 forms of a cognitive abilities test that varied in their diagnosticity of success, diagnosticity of failure, and difficulty. In accordance with the self-assessment view, test choice was found to be positively related to diagnosticity of success and, to a lesser extent, diagnosticity of failure. Test choice was also dependent on the interaction of diagnosticity and difficulty in a manner that was more consistent with the self-assessment view. In a 2nd study that provided more precise measurement of perceived diagnosticity and expected success, data from 40 undergraduates indicate that the motives for self-assessment and self-enhancement were each reliably related to task preference. Of the two, self-assessment motivation was a stronger determinant of task preference. Results suggest that task choice is governed largely by a concern for accurate self-appraisal and that current models may require revisions that take into account the less-than-accurate appraisal of diagnosticity. (37 ref) (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Utilizing Instructional Consultations to Enhance the Teaching Performance of Engineering Faculty

Although many kinds of data can be used to guide instructional consultations, research comparing the efficacy of such data is scant, especially in engineering. In this study, multiple modes of assessment were used to evaluate the impact of consultations informed by different kinds of data. This study illuminates two key aspects of instructional consultations: (1) their efficacy varies depending on the kind of data used to guide them, with student feedback from a Small Group Instructional Diagnosis (SGID) having the largest positive impact, and (2) the instructional consultant plays a key role in helping both interpret the available data and identify strategies for improvement. These findings suggest three implications for practice: (1) whenever possible, SGID‐based consultations should be offered systematically and proactively for engineering faculty, (2) data for other kinds of consultations should be tailored to the needs of the individual instructor, and (3) instructional consultants should be available to collaborate with faculty to enhance their teaching, thereby building an engineering culture that actively supports teaching and learning.