Determination of methionine by gas-liquid chromatography: Modifications in its application to legumes and cereals

Peptide-bound methionine when reacted with CNBr releases methyl thiocyanate which is quantitatively measured by gas–liquid chromatography. Seeds of varieties of legume contain γ-glutamyl-S-methylcysteine, which also reacts with CNBr to give methyl thiocyanate, which results in elevated apparent methionine values. An extraction procedure for its removal was developed and applied to many legume varieties. Methionine values agreed with those obtained by ion-exchange chromatography after performic acid oxidation; an exception was Phaseolus mungo (black gram). Samples of Ph. mungo from several sources all contained substantial amounts of free methionine but, as no γ-glutamyl-S-methylcysteine was-present, the need for extraction was eliminated. For the determination of methionine in cereals, conditions were adapted to decrease gel formation in the presence of formic acid and CNBr, and to eliminate interference at the gas chromatography stage. This was achieved by a mild acid hydrolysis prior to CNBr reaction, conditions for which are described.     

The use of Odors at Different Spatial Scales: Comparing Birds with Fish

Salmon travel hundreds of kilometers of open ocean and meandering rivers to return to their natal stream to spawn; procellariiform seabirds soar over thousands of kilometers of the ocean's surface searching for foraging opportunities and accurately return to their nesting islands. These large-scale olfactory-guided behaviors are among the most dramatic examples of animal navigation ever described. At much closer ranges, the sense of smell can be used for behaviors as diverse as tracking prey, nest location, and mate selection. Both fish and birds face similar problems interpreting olfactory information in fluid mediums where odors are dispersed as filamentous patches. Similar to insects, which have served as model organisms for investigating olfactory related behaviors, the few fish and bird species that have been studied tend to use olfactory information in conjunction with other sensory modalities. Similar to insects, fish and birds also employ oscillatory or cross-stream movement as sampling mechanisms. This review compares and contrasts the use of odors by fish and birds over a range of spatial scales that span from thousands of kilometers to less than a meter. In so doing, we identify behavioral similarities and new questions that need to be addressed regarding the olfactory ecology of these diverse groups of organisms.     

Simulation of Nitrous Oxide Emissions from Wheat-cropped Soils using CERES

Estimation of nitrous oxide (N₂O) emissions from arable soils, in relation to crop fertilization, is essential to devise strategies to mitigate the impact of agriculture on global warming. This paper presents the development and test of a N₂O model resulting from the linkage of a dynamic soil-crop simulation model (CERES) with two sub-models of N₂O production and reduction in soils. These sub-models (NOE and NGAS) account for both the nitrification and denitrification pathways. The resulting models (CERES–NOE and CERES–NGAS) were tested against experimental data collected on three contrasting wheat-cropped soils representative of the Beauce agricultural region in France. Although the input variables for the N₂O modules were correctly simulated, CERES–NGAS was over-responsive to soil water content in a Haplic Calcisol, and strongly over-estimated the N₂O fluxes as a result. On the other hand, CERES–NOE predicted correct mean N₂O emission levels for all sites, but failed to simulate the peak fluxes observed in the weeks following fertilizer application in the most N₂O-productive soil. Both models achieved root mean squared errors in the 23–26 g N–N₂O ha⁻¹ day⁻¹ range, significantly higher than the average experimental error on the measurements. On the other hand, their mean deviations were acceptable, being lower than 2.2 g N–N₂O ha⁻¹ day⁻¹, compared with a mean observed flux of 7.9 g N–N₂O ha⁻¹ day⁻¹. Overall, the response of CERES–NOE to soil type was more accurate, but this came at the cost of costly, site-specific characterization on the soils’ biological properties. The development of pedo-transfer functions to infer these parameters from basic soil characteristics appears as a pre-requisite for the use of CERES–NOE on a wider scale.     

Does competition for phosphate supply explain the invasion pattern of Elodea species?

Two invasive aquatic plants, Elodea canadensis and Elodea nuttallii, occurred in north-eastern France. In this study, we examine the influence of phosphorus availability in soft water streams to explain the invasion pattern of exotic species (E. nuttallii and E. canadensis) compared to native plants (Callitriche platycarpa, Ranunculus peltatus). Total phosphorus was measured in these four aquatic macrophytes. Sediment total phosphorus and water-soluble reactive phosphorus were also analysed each season in 2001. Phosphorus content in the two invasive species and in R. peltatus was higher than in C. platycarpa. Elodea species are adapted to the seasonal phosphorus fluctuations as well as R. peltatus and exhibited high phosphorus storage ability. The high fluctuation availability of resources in space or/and time favoured the spread of the invasive plants and confirms the theory of invasibility of Davis et al. [2000. Fluctuating resources in plant communities: a general theory of invasibility. J. Ecol. 88, 528-534]. The eutrophication process increases the invasibility of E. nuttallii's, while inducing competition between E. nuttallii and native macrophyte species.     

Let the light be a guide: Chromophore communication in metal-organic frameworks

The photonic characteristics of chromophore-containing metal-organic frameworks(MOFs)have led to extensive photophysical studies in an effort to capitalize on the potency of precisely controlled chromophore ensembles.Several examples have laid the foundation that demonstrates how photophysical properties of chromophores can be manipulated by tuning their communications(interactions)through integration within a MOF matrix.The main focus of this review is on harnessing the versatile MOF platform to accentuate the photophysical properties of integrated chromophores.In particular,this review will highlight chromophore dynamics that enhance,alter,or tune the photoluminescence response of single-and multi-chromophore-containing scaffolds,as well as alignment-guided anisotropic fluorescence.Building upon this groundwork,utilization of a hybrid crystalline motif can induce preferential orientation of chromophores resulting in enhanced communication and tailored behavior compared to randomly oriented emissive molecules.Moreover,frameworks that produce upconverted emission via sensitized triplet-triplet annihilation(sTTA),excited-state absorption(ESA),energy transfer upconversion(ETU),multi-photon absorption(MPA),or second-harmonic generation(SHG)can invoke dynamic control of material properties using photochromic linkers and will be discussed herein with a focus on the effects of chromophore alignment.Integration within a framework is a vehicle tofuse chromophores into solid-state platforms,opening an avenue for chromophore utilization in applications such as portable electronics that require solids or thin films.For those reasons,the design of chromophore-containing MOFs with desirable properties that rely on the alignment and communication of hundreds of chromophores within a single platform is a pressing demand for the development of futuristic technologies.     

Attitudes toward life and death in suicidal, normal, and chronically ill children: An extended replication.

Evaluated the attitudes toward life and death held by 23 6–12 yr old suicidal children, 28 6–22 yr old chronically ill children, and 33 6–22 yr old normal children by examining 4 attitudes toward life and death: attraction to life, repulsion by life, attraction to death, and repulsion by death. The measurement of the intensities of these attitudes was obtained by means of the Ss' quantitative responses to questions that followed fairy tale stories. Each of the stories represented 1 of the 4 attitudes. Parallel forms of the test were administered in a time interval of 6 wks. ANOVA showed that the 4 attitudes were distinguishable from each other. The response profiles of suicidal Ss showed significantly lower repulsion by death than those of normal Ss. Chronically ill Ss presented the highest degree of repulsion by life and scored higher than normal Ss on attraction to death. On repulsion by death, they scored higher than suicidal Ss but lower than normal children. All Ss scored well on attraction to life. Findings document the construct validity of the theoretical model. (13 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

New generation of amino coumarin methyl sulfonate-based fluorogenic substrates for amidase assays in droplet-based microfluidic applications

Droplet-based microfluidics is a powerful tool for biology and chemistry as it allows the production and the manipulation of picoliter-size droplets acting as individual reactors. In this format, high-sensitivity assays are typically based on fluorescence, so fluorophore exchange between droplets must be avoided. Fluorogenic substrates based on the coumarin leaving group are widely used to measure a variety of enzymatic activities, but their application in droplet-based microfluidic systems is severely impaired by the fast transport of the fluorescent product between compartments. Here we report the synthesis of new amidase fluorogenic substrates based on 7-aminocoumarin-4-methanesulfonic acid (ACMS), a highly water-soluble dye, and their suitability for droplet-based microfluidics applications. Both substrate and product had the required spectral characteristics and remained confined in droplets from hours to days. As a model experiment, a phenylacetylated ACMS was synthesized and used as a fluorogenic substrate of Escherichia coli penicillin G acylase. Kinetic parameters (k(cat) and K(M)) measured in bulk and in droplets on-chip were very similar, demonstrating the suitability of this synthesis strategy to produce a variety of ACMS-based substrates for assaying amidase activities both in microtiter plate and droplet-based microfluidic formats.     

Social regulation of serotonin in the auditory midbrain.

The neuromodulator serotonin regulates auditory processing and can increase within minutes in response to stimuli like broadband noise as well as nonauditory stressors. Little is known about the serotonergic response in the auditory system to more natural stimuli such as social interactions. Using carbon-fiber voltammetry, we measured extracellular serotonin in the auditory midbrain of resident male mice during encounters with a male intruder. Serotonin increased in the inferior colliculus (IC) over the course of a 15 minute interaction, but not when mice were separated with a perforated barrier. Several behaviors, including the amount of immobility and anogenital investigation performed by the resident, were correlated with the serotonergic response. Multiple intrinsic factors associated with individual mice also correlated with the serotonergic response. One of these was age: older mice had smaller serotonergic responses to the social interaction. In a second interaction, individual identity predicted serotonergic responses that were highly consistent with those in the first interaction, even when mice were paired with different intruders. Serotonin was also significantly elevated in the second social interaction relative to the first, suggesting a role for social experience. These findings show that during social interaction, serotonin in the IC is influenced by extrinsic factors such as the directness of social interaction and intrinsic factors including age, individual identity, and experience. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Depression self-rating scale: Utility with child psychiatric inpatients.

Assessed the validity of a depression self-rating scale (DSRS) with 22 female and 60 male (mean age 10.76 yrs) consecutively admitted psychiatric inpatients by determining the extent to which DSRS scores discriminated depressed from nondepressed Ss. Results indicate that DSRS scores significantly discriminated between Ss who had been independently diagnosed as meeting DSM-III criteria for depressive and nondepressive disorders. Cutting scores were generated for the DSRS, producing overall rates of correct classifications ranging from 66 to 77%, with few false positive errors. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Distributed and collaborative visualization of large data sets using high-speed networks

We describe an architecture for distributed collaborative visualization that integrates video conferencing, distributed data management and grid technologies as well as tangible interaction devices for visualization. High-speed, low-latency optical networks support high-quality collaborative interaction and remote visualization of large data.