Characterization of glycolytic metabolism and ion transport of Candida albicans

The main energetic pathways, fermentation and respiration, and the general ion transport properties of Candida albicans were studied. Compared to Saccharomyces cerevisiae, we found that in C. albicans: (a) the cell mass yield when grown in YPD was significantly larger; (b) it required longer times to be starved of endogenous substrates; (c) ethanol production was lower but significant; (d) respiration was also lower; (e) it showed a small activity of an alternative oxidase; (f) fermentation and oxidative phosphorylation seemed to compete for both ADP and NADH; and (g) NADH levels were lower. Regarding ion transport and compared to S. cerevisiae: (a) the general mechanism was similar, with a plasma membrane H⁺‐ATPase that generates both a plasma membrane ΔpH and a ΔΨ, the latter being responsible for driving K⁺ inside; (b) its acidification capacity is slightly smaller and less sensitive to activation by high pH; and (c) the presence of K⁺ results in a large activation of both respiration and fermentation, most probably due to the energy required in the process. ADP produced by H⁺‐ATPase stimulation by high pH or the addition of K⁺ at low pH results in the increase of both respiration and fermentation. Copyright © 2012 John Wiley & Sons, Ltd.     

Cationic Hybrid Hydrogels from Amino‐Acid‐Based Poly(ester amide): Fabrication,Characterization, and Biological Properties

A family of biodegradable, biocompatible, water soluble cationic polymer precursor, arginine‐based unsaturated poly (ester amide) (Arg‐UPEA), is reported. Its incorporation into conventional Pluronic diacrylate (Pluronic‐DA) to form hybrid hydrogels for a significant improvement of the biological performance of current synthetic hydrogels is shown. The gel fraction (G_f), equilibrium swelling ratio (Q_eq), compressive modulus, and interior morphology of the hybrid hydrogels as well as their interactions with human fibroblasts and bovine endothelial cells are fully investigated. It is found that the incorporation of Arg‐UPEA into Pluronic‐DA hydrogels significantly changes their Q_eq, mechanical strength, and interior morphology. The structure–property relationship of the newly fabricated hybrid hydrogels is studied in terms of the chemical structure of the Arg‐UPEA precursor, i.e., the number of methylene groups in the Arg‐UPEA repeating unit. The results indicate that increasing methylene groups in the Arg‐UPEA repeating unit increases Q_eq and decreases the compressive modulus of hydrogels. When compared with a pure Pluronic hydrogel, the cationic Arg‐UPEAs/Pluronic hybrid hydrogels greatly improve the attachment and proliferation of human fibroblasts on hydrogel surfaces. A bovine aortic endothelial cells (BAEC) viability test in the interior of the hydrogels shows that the positively charged hybrid hydrogels can significantly improve the viability of the encapsulated endothelial cell over a 2 week study period when compared with a pure Pluronic hydrogel.     

Scorodite dissolution kinetics: implications for arsenic release

We have measured the rate of scorodite (FeAsO4.2H2O) dissolution over an environmentally relevant range of pH and temperature conditions. Dissolution rates, calculated using arsenic (As) as the reaction progress variable, were slowest at pH 3 and increased with both decreasing and increasing pH. Comparison of the pH-dependence of the dissolution rates with a scorodite stability diagram suggests that our measurements of dissolution rate at pH 2 reflect congruent dissolution, and those at and above pH 3 reflect incongruent dissolution. Because As was used as the reaction progress variable, and recognizing that As may adsorb to iron hydroxides during incongruent dissolution of scorodite, the derived rates may be underestimated. The pH and temperature dependence of scorodite dissolution rates determined in these experiments have implications for the stability of scorodite at field sites and also for the potential use of scorodite to sequester As. Although scorodite dissolution is slow, it can be enhanced by up to a half order of magnitude by increases in pH and temperature.     

Grapefruit juice and its furocoumarins inhibits autoinducer signaling and biofilm formation in bacteria

Cell-to-cell communications in bacteria mediated by small diffusible molecules termed as autoinducers (AI) are known to influence gene expression and pathogenicity. Oligopeptides and N-acylhomoserine lactones (AHL) are major AI molecules involved in intra-specific communication in gram-positive and gram-negative bacteria respectively, whereas boronated-diester molecules (AI-2) are involved in inter-specific communication among both gram-positive and gram-negative bacteria. Naturally occurring furocoumarins from grapefruit showed >95% inhibition of AI-1 and AI-2 activities based on the Vibrio harveyi based autoinducer bioassay. Grapefruit juice and furocoumarins also inhibited biofilm formation by Escherichia coli O157:H7, Salmonella typhimurium and Pseudomonas aeruginosa. These results suggest that grape fruit juice and furocoumarins could serve as a source to develop bacterial intervention strategies targeting microbial cell signaling processes.     

Antifungal activity of Mexican oregano (Lippia berlandieri Shauer)

Antifungal and sensorial properties of spices have been recognized for years. The antifungal compounds are products of the plant's secondary metabolism, and the action of those compounds could be used to inhibit the growth of spoilage and pathogenic microorganisms in food. Mexican oregano (Lippia berlandieri) grows wildly in the desert zone of Mexico and is usually added to regional foods. The goal of this study was to evaluate the antifungal activity of Mexican oregano versus food-contaminant fungi. Fungi were isolated from spoiled fruit and vegetables and identified according to morphological characteristics. The antifungal activity of oregano was evaluated by radial growth measurement on potato dextrose agar added with dried oregano (0.25 to 4.0%). The essential oil antifungal activity of oregano was also evaluated by the diffusion well test. Twenty-one fungal strains were isolated, which included Penicillium, Geotrichum, Aspergillus, and Bipolaris. In seven of the 21 strains, no inhibitory effect was observed at either concentration of oregano. An increase in growth at the lower or higher concentrations of oregano, when compared to the control, was observed in two fungal strains; in 12 strains, a strong inhibitory effect of oregano was evident. The oregano essential oil was inhibitory to all fungal strains, but there were differences in the extent of the effect. Although the antifungal effect of oregano is strongly established, there was a differential effect with the fungal strains studied. Besides pathogenic fungi and bacteria, microbial spoilage flora should be considered when the addition of spices for food preservation is proposed.     

Die Beurteilung von Flu?wasser auf Grund der Bestimmung von Permanganatverbrauch und Chlorzahl

Ohne Zusammenfassungbedeutet mit Abbildungen.     

Thematic Apperception Test method for the differentiation of families of schizophrenics, delinquents, and "normals."

Assessed the dimension of Parent * Child interactional behavior from 240 TAT stories told by parents of 10 schizophrenics, 10 delinquents, and 10 "normals." A modified content analysis was applied to stories dealing with parent-child plots. Common underlying factors contributing to similar story qualities were abstracted into higher order classes of story behavior. 3 modal behavior categories were defined: personally involved, child-centered, flexible interactions (A), impersonally involved, superficial interactions (B), and overinvolved, parent-centered interactions (C). Blind rating of the stories by Categories A, B, and C significantly and reliably differentiated the 3 parental groups. Blind rating of a separate series of TAT stories told by 20 mothers of schizophrenic children and 20 mothers of normal children using the National Institute of Mental Health method significantly differentiated the 2 parental groups. Processes that may have determined the different patterns of narrated Parent-Child interactions are considered. (22 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parent-child relationships as systems of support or risk for adolescent suicidality.

This study examined a process model of predicting adolescent suicidality. Adolescent emotional distress was hypothesized to mediate the relationship between parental behaviors and subsequent adolescent suicidality. The parental behaviors studied included parental warmth and parental hostility. A sample of 451 families from rural Iowa participated in this longitudinal study, which included both observational and self-report data. Models were tested with structural equation modeling. Adolescent emotional distress was found to be a mediating variable between paternal warmth and adolescent suicidality. Results indicated that maternal warmth predicted adolescent suicidality but not emotional distress. Parental hostility did not predict either latent variable. Clinical implications are provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Learning mathematics from procedural instruction: Externally imposed goals influence what is learned.

Do externally imposed achievement goals influence what children learn from procedural instruction? Third- and 4th-grade children's goals were manipulated toward either learning or performance. All children were then taught a procedure for solving mathematical equivalence problems (e.g., a?+?b?+?c?=?a?+?_). Children who were given learning goals were initially more likely to gain conceptual knowledge from the procedural lesson than were children who were given performance goals. After a 2-week period, however, children who were given performance goals exhibited the same conceptual gains as children who were given learning goals. Both initially and after the 2-week period, children who were given either goal were more likely to extend their knowledge beyond the taught procedure than were children who were not given goals. External sources such as teachers and parents may have the potential to foster children's learning by shaping children's goals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)