Investigation of water environments in a C18 bonded silica phase using 1H magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy.

High resolution 1H magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectra have been obtained on typical C18 bonded silicas used in chromatographic solid-phase extraction separations. It has been shown for the first time that water molecules distributed in distinct physico-chemical environments within the chromatographic system can be detected directly using a simple 1H MAS NMR measurement. The resonances assigned to water protons in differing physico-chemical environments have distinct chemical shifts, line widths, relaxation times (T1 and T2) and also exhibit temperature dependent coalescence behaviour. This novel MAS approach may lead to a better understanding of the environments of other analytes in mixtures during such separations.

Pattern recognition analysis of endogenous cell metabolites for high throughput mode of action identification: removing the postscreening dilemma associated with whole-organism high throughput screening.

Although whole-organism HTS can give clear indications of in vivo activity, typically few clues are given as to the mechanism of action (MOA), and determining the MOA for large numbers of active compounds can be costly and complex-an alternative approach is required. This report demonstrates that it is possible to conduct relatively high throughput MOA characterization of HTS hits utilizing a single sample preparation and analytical method. By monitoring a wide range of endogenous cellular metabolites via (1)H nuclear magnetic resonance spectroscopy, the MOA of herbicides can be predicted using computational methods to compare the metabolite perturbation patterns. Herbicides that induce a characteristic pattern of metabolic perturbation in maize include inhibitors of acetolactate synthase, acetyl co-enzyme A carboxylase, protoporphyrinogen oxidase, 5-enolpyruvylshikimate-3-phosphate synthase, and phytoene desaturase. In soya, photosystem II inhibitors can also be detected, further demonstrating that this method is not limited to inhibitors of enzymes that directly act upon endogenous metabolites, or a single species. The methods, including data analysis, can be readily automated, enabling relatively high throughput MOA elucidation of whole-organism screen hits. Additionally, for compounds with a novel MOA, this approach may lead to MOA identification faster than traditional methods. It is envisaged that application of these data analysis methods to other data types-for example, transcription (mRNA) or translation (protein) profiles-is likely to permit higher throughput with smaller sample requirements, along with ability to discriminate MOAs that are not adequately discriminated based upon endogenous metabolite profiles.

Mass spectrometrically detected directly coupled high performance liquid chromatography/nuclear magnetic resonance spectroscopy/mass spectrometry for the identification of xenobiotic metabolites in maize plants.

Reconstructed ion chromatograms have been used to identify relevant high performance liquid chromatography (HPLC) peaks in a directly coupled high performance liquid chromatography/nuclear magnetic resonance spectroscopy/mass spectrometry (HPLC/NMR/MS) experiment. This has been applied to a study of the metabolism of a model compound, 5-nitropyridone (2-hydroxy-5-nitropyridine), in maize plants grown hydroponically. By monitoring the on-flow reconstructed ion chromatogram corresponding to the 5-nitropyridone fragment at m/z 143, and additional molecular ions corresponding to metabolites identified as products from similar compounds, relevant peaks were identified rapidly for subsequent stopped-flow 1H NMR spectroscopic analysis. The combination of coupled HPLC/NMR/MS enabled the direct identification of three metabolites, namely the N-glucoside, N-malonylglucoside, and O-malonylglucoside. This work demonstrates the power of HPLC/NMR/MS for the structural elucidation of xenobiotic metabolites in complex biological matrices (such as plant material) with minimal sample preparation. In particular, using mass spectrometry for the initial identification of relevant HPLC peaks allows the analysis of complex samples without the necessity for other spectroscopic markers, such as 19F NMR signal for fluorinated compounds or UV spectroscopy for molecules with strong UV chromophores.

Application of directly coupled HPLC-NMR-MS/MS to the identification of metabolites of 5-trifluoromethylpyridone (2-hydroxy-5-trifluoromethylpyridine) in hydroponically grown plants.

Directly coupled HPLC-NMR-MS was used to characterize two major metabolites of 5-trifluoromethylpyridone (2-hydroxy-5-trifluoromethylpyridine), a model compound for herbicides, after it had been dosed into hydroponically grown maize plants. The combination of NMR and MS data allowed the identification of both of these metabolites, namely, the N-glucoside and O-malonylglucoside conjugates of the parent pyridone. This work demonstrates the efficiency and the potential application of HPLC-NMR-MS to the investigation of the metabolism of agrochemicals. The work also indicates that combination of the use of hydroponically grown plants and directly coupled HPLC-NMR-MS allows rapid identification of metabolites with little sample preparation.

Differences in depression and self-esteem reported by learning disabled and behavior disordered middle school students.

Although generalizations from research are helpful in guiding problem identification and interventions in a school setting, characteristics of specific groups must not be overlooked if all students are to be served effectively. Differences in the areas of self-reported self-esteem and depression are frequently pertinent to decisions and recommendations educational professionals are called on to make. The current study examined differences in the level of self-reported self-esteem and depression between learning disabled and behavior disordered middle school students. Sixty-one participants completed the Coopersmith Self-Esteem Inventory (CSEI) and the Children's Depression Inventory (CDI). Similarities and differences between learning disabled and behavior disordered students were identified.

An investigation of the relationship between color choice and depression measured by the Beck Depression Inventory.

The relationship between self-reported depression and color preference was investigated. It was proposed that a cognitive schema would be activated affecting negatively that part of the environment selected for cognitive preference. When requested to select a series of preferred colors, the 72 undergraduates scoring above 10 on the Beck Depression Inventory tended to choose black or brown. It is believed that internal schema represented in 3 questions may be reflected in color choice(s).