Stimulatory effects of tannins and cholic acid on tryptic hydrolysis of proteins: Ecological implications

The biochemical basis for considering tannins as digestion inhibitors has been reexamined. Both stimulatory and inhibitory effects of tannins on tryptic hydrolysis are reported. We show how stimulation may result from tannin-induced structural changes in the substrate protein, effectively denaturing it. The surfactant and bile constituent cholic acid also produced similar stimulatory effects. These results have considerable implications for normal digestive physiology as well as for the impact of tannins on argicultural and natural herbivore populations.     

Psychological testing in evaluation of child sexual abuse

In order to assess the utility of psychological testing in evaluating allegations of child sexual abuse, the empirical literature is reviewed in an attempt to answer two questions. First, are there systematic and significant differences on psychological tests between sexually abused and nonabused children? Second, are these differences on psychological testing a direct result of sexual abuse, or are they a result of other coexisting factors that might cause psychological distress? Cognitive measures, personality inventories, symptomatology checklists, and projective tests with sexually abused children are reviewed. While a variety of standardized instruments have been administered to sexually abused children, relatively few have been utilized in empirical studies. Findings have been mixed, with stronger differences between sexually abused and nonabused children generally found on measures completed by parents than on measures administered directly to children. Sexually abused children often fall between nonabused and psychiatric groups. Use of measures specific to sexual abuse is advocated. While psychological tests may currently have limited use in validating suspected sexual abuse, they may be extremely useful in the clinical treatment of the child.     

Changes in catecholamine levels and turnover rates in hypothalamic, vocal control, and auditory nuclei in male zebra finches during development

The catecholamines norepinephrine (NE) and dopamine (DA) have been implicated in the sexual differentiation of brain and behavior and in species-specific learning in several species. To determine if these neurotransmitters might be involved in sexual differentiation of the vocal control system and song learning in male zebra finches, NE and DA levels and turnover rates were quantified in 10 behaviorally relevant brain nuclei [6 vocal control (VCN), 2 auditory (AN), and 2 hypothalamic (HN)] at four critical points during sexual differentiation of the VCN and the period of song learning, 25, 35, 55, and 90 days of age. Some birds were pretreated with alpha-methyl-para-tyrosine (alphaMPT) to allow estimation of NE and DA turnover rates. NE and DA levels in microdissected nuclei were quantified using high-performance liquid chromatography with electrochemical detection. AlphaMPT treatment suppressed catecholamine synthesis just as effectively in juveniles as it does in adults and proved an effective method for estimating NE and DA turnover rates. Patterns of NE and DA function in most VCN and AN over development were quite different from those in HN in which NE and DA function changed gradually and showed no striking peaks. NE turnover rates changed significantly over development in all six VCN [nucleus interfacialis (Nlf), high vocal center (HVC), nucleus robustus of the archistriatum (RA), dorsomedial portion of the intercollicular nucleus (DM), Area X of the parolfactory lobe, and lateral portion of the magnocellular nucleus of the anterior neostriatum (IMAN)]; one AN [nucleus mesencephalicus lateralis pars dorsalis (MLd)], and one HN [preopticus anterior (POA)]. NE levels changed significantly in two VCN (Nlf and Area X). In Nlf, RA, Area X, IMAN, and MLd, NE levels and/or turnover rates showed a striking peak at day 25, which was not seen in HN. Both DA levels and turnover rates changed profoundly over development in 5 of 6 VCN (Nlf, RA, DM, Area X, and IMAN) and both AN (MLd and Field L). These nuclei showed striking peaks in DA levels and turnover rates, primarily on day 35 and/or 55, which then declined profoundly by day 90. This contrasted with the minimal change in DA turnover rates seen in one HN (POA) and the sixth VCN, HVC. In several VCN and AN, NE and DA levels and turnover rates during development reached levels never seen in adult males. Previous research has shown that catecholamine function is heightened in VCN during development compared to surrounding tissues. Our data demonstrate that NE and DA function during development shows pronounced peaks in most VCN not seen in HN. This is interesting because both VCN and HN are hormone sensitive, and both show hormone-modulated NE and DA function in adult males. The timing of these peaks suggests that increased catecholaminergic function may be involved in sexual differentiation of the VCN and song learning in finches.     

New Generations: Sequencing Machines and Their Computational Challenges

New generation sequencing systems are changing how molecular biology is practiced. The widely promoted ＄1000 genome will be a reality with attendant changes for healthcare, including personalized medicine. More broadly the genomes of many new organisms with large samplings from populations will be commonplace. What is less appreciated is the explosive demands on computation, both for CPU cycles and storage as well as the need for new computational methods. In this article we will survey some of these develo...     

Quantification of polycyclic aromatic hydrocarbons in the NIST standard reference material (SRM1649A) urban dust using thermal desorption GC/MS

A thermal desorption GC/MS technique has been developed for the quantification of polycyclic aromatic hydrocarbons (PAHs) in airborne particulate matter using the NIST Standard Reference Material (SRM1649a) Urban Dust. The technique was developed using standard linearity tests in order to establish optimum sample weights and optimum desorption and chromatographic parameters. This direct analysis technique eliminates the use of solvents in the sample preparation (reducing volatile component losses) and also significantly reduces the sample preparation time (no extraction procedure). The technique has been shown to give linearity in terms of the overall TIC response as well as for a prominent series of n-alkanes (C20-C33) and 10 NIST priority PAHs, 8 of which have been quantified. The technique is reported to be uniquely sensitive (PAH concentrations 2-6 mg kg(-1)) and reproducible (MW = 178-228 SD < or =0.228 mg kg(-1), < or =7%; MW = 252 SD < or =0.922 mg kg(-1), < or =33%) over the range of sample weights (1-5 mg). Such sample weights illustrate that the technique can be equally applied to the analysis of airborne particulate samples collected over short time periods (24-48 h) using only commonly used low-volume collection devices.     

Maximum entropy angular response patterns of microwave transhorizon signals

The maximum entropy method (MEM) is applied in the computation of angular response patterns based on amplitude and phase measurements from a 12-element vertical array receiving transhorizon microwave signals. The patterns are compared with those obtained using conventional Fourier transform techniques (FTT). The MEM patterns exhibit higher resolution and lower sidelobes, revealing in some cases features not seen in the FTT patterns.     

Marketing quality differentiated power

A panel discussion sponsored by the Marketing Task Force of the Demand Side Subcommittee is summarized. The panel discussed customers' growing needs for electrical services with different levels of quality and utilities' response to this change in the market. Panel members included a consumer, technical experts, and marketing experts. The discussion is particularly important to utility personnel and marketing professionals interested in marketing solutions to power quality problems     

Cellular oxygenation of 12-hydroxyeicosatetraenoic acid and 15-hydroxyeicosatetraenoic acid by 5-lipoxygenase is stimulated by 5-lipoxygenase-activating protein

It has been proposed that 5-lipoxygenase (5-LO)-activating protein (FLAP) is an arachidonate transfer protein for leukotriene biosynthesis. Using the Spodoptera frugiperda (Sf9) insect cells, we demonstrate that FLAP causes a large stimulation (190-fold) of the conversion of 12(S)-hydroxyeicosatetraenoic acid (12(S)-HETE) to 5, 12-diHETE when co-expressed with 5-lipoxygenase. We also demonstrate that FLAP can stimulate (2-2.5-fold) the oxygenation of 15(S)-HETE by 5-LO to 5,15-diHETE. The stimulation of both 12(S)-HETE and 15(S)-HETE oxygenation by 5-LO is completely inhibitable by the FLAP inhibitor, MK-886. In order to determine which residues of FLAP are important for 12(S)-HETE and arachidonic acid utilization by 5-LO, various mutants of FLAP were co-expressed with 5-LO in Sf9 cells. The FLAP deletion mutants del 37-53, del 52-58, del 106-108, and del 148-161 and the point mutant D62N were analyzed. The D62N mutation, which reduces the binding of indole inhibitors to FLAP, had no effect on the stimulation of substrate utilization by 5-LO. In contrast to wild type FLAP, the mutant proteins del 37-53, del 106-108, and del 148-161 failed to stimulate 12(S)-HETE and arachidonic acid utilization by 5-LO. Only one of the latter three mutations (del 37-53) has been shown to abolish the binding of indole inhibitors to FLAP. These results suggest that the lipid binding site of FLAP overlaps the inhibitor binding site and occupies several regions of the protein not essential for inhibitor binding. Because FLAP can stimulate the utilization of 12(S)-HETE, 15(S)-HETE, and arachidonic acid by 5-LO, FLAP may also function as a more general lipid carrier protein for the biosynthesis of multiple oxygenation products of arachidonic acid in addition to its role in leukotriene biosynthesis.