Descriptions of a new species of Physa from the Pleistocene of Florida

http://deepblue.lib.umich.edu/bitstream/2027.42/56603/1/OP164.pd

Localization of sterols and oxysterols in mouse brain reveals distinct spatial cholesterol metabolism

Dysregulated cholesterol metabolism is implicated in a number of neurological disorders. Many sterols, including cholesterol and its precursors and metabolites, are biologically active and important for proper brain function. However, spatial cholesterol metabolism in brain and the resulting sterol distributions are poorly defined. To better understand cholesterol metabolism in situ across the complex functional regions of brain, we have developed on-tissue enzyme-assisted derivatization in combination with microliquid extraction for surface analysis and liquid chromatography-mass spectrometry to locate sterols in tissue slices (10 µm) of mouse brain. The method provides sterolomic analysis at 400-µm spot diameter with a limit of quantification of 0.01 ng/mm2. It overcomes the limitations of previous mass spectrometry imaging techniques in analysis of low-abundance and difficult-to-ionize sterol molecules, allowing isomer differentiation and structure identification. Here we demonstrate the spatial distribution and quantification of multiple sterols involved in cholesterol metabolic pathways in wild-type and cholesterol 24S-hydroxylase knockout mouse brain. The technology described provides a powerful tool for future studies of spatial cholesterol metabolism in healthy and diseased tissues

Mass spectrometry imaging of cassette-dosed drugs for higher throughput pharmacokinetic and biodistribution analysis

Cassette dosing of compounds for preclinical drug plasma pharmacokinetic analysis has been shown to be a powerful strategy within the pharmaceutical industry for increasing throughput while decreasing the number of animals used. Presented here for the first time is data on the application of a cassette dosing strategy for label-free tissue distribution studies. The aim of the study was to image the spatial distribution of eight nonproprietary drugs (haloperidol, bufuralol, midazolam, clozapine, terfenadine, erlotinib, olanzapine, and moxifloxacin) in multiple tissues after oral and intravenous cassette dosing (four compounds per dose route). An array of mass spectrometry imaging technologies, including matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI MSI), liquid extraction surface analysis tandem mass spectrometry (LESA-MS/MS), and desorption electrospray ionization mass spectrometry (DESI-MS) was used. Tissue analysis following intravenous and oral administration of discretely and cassette-dosed compounds demonstrated similar relative abundances across a range of tissues indicating that a cassette dosing approach was applicable. MALDI MSI was unsuccessful in detecting all of the target compounds; therefore, DESI MSI, a complementary mass spectrometry imaging technique, was used to detect additional target compounds. In addition, by adapting technology used for tissue profiling (LESA-MS/MS) low spatial resolution mass spectrometry imaging (∼1 mm) was possible for all targets across all tissues. This study exemplifies the power of multiplatform MSI analysis within a pharmaceutical research and development (R&D) environment. Furthermore, we have illustrated that the cassette dosing approach can be readily applied to provide combined, label-free pharmacokinetic and drug distribution data at an early stage of the drug discovery/development process while minimizing animal usage

Characterization of an Aggregated Three-Dimensional Cell Culture Model by Multimodal Mass Spectrometry Imaging

Mass spectrometry imaging (MSI) is an established analytical tool capable of defining and understanding complex tissues by determining the spatial distribution of biological molecules. Three-dimensional (3D) cell culture models mimic the pathophysiological environment of in vivo tumors and are rapidly emerging as a valuable research tool. Here, multimodal MSI techniques were employed to characterize a novel aggregated 3D lung adenocarcinoma model, developed by the group to mimic the in vivo tissue. Regions of tumor heterogeneity and the hypoxic microenvironment were observed based on the spatial distribution of a variety of endogenous molecules. Desorption electrospray ionization (DESI)-MSI defined regions of a hypoxic core and a proliferative outer layer from metabolite distribution. Targeted metabolites (e.g., lactate, glutamine, and citrate) were mapped to pathways of glycolysis and the TCA cycle demonstrating tumor metabolic behavior. The first application of imaging mass cytometry (IMC) with 3D cell culture enabled single-cell phenotyping at 1 μm spatial resolution. Protein markers of proliferation (Ki-67) and hypoxia (glucose transporter 1) defined metabolic signaling in the aggregoid model, which complemented the metabolite data. Laser ablation inductively coupled plasma (LA-ICP)-MSI analysis localized endogenous elements including magnesium and copper, further differentiating the hypoxia gradient and validating the protein expression. Obtaining a large amount of molecular information on a complementary nature enabled an in-depth understanding of the biological processes within the novel tumor model. Combining powerful imaging techniques to characterize the aggregated 3D culture highlighted a future methodology with potential applications in cancer research and drug development

Satisfaction with Life Scale among adolescents and young adults in Portugal: extending evidence of construct validity

The paper presents three empirical studies designed to extend the test of the construct validity of the Satisfaction With Life Scale (SWLS) among Portuguese students. In the first study, the responses of 461 elementary and secondary education students were submitted to a principal component analysis. A solution of one single factor was chosen, accounting for 55.7 % of the total variance, with Cronbach alpha coefficient and inter-item correlation above .70 and .20, respectively. The second study used a sample of 317 undergraduate students and registered a similar factor solution for SWLS (/pq = 0.99), which accounted for 65.6 % of the total variance (Cronbach alpha .89 and inter-item correlation above .20). A test–retest analysis registered coefficients of .70 (T2) and .77 (T3) and no significant statistically differences between T2, T3 and T1. The third study used a sample of 107 foster care youths from elementary and secondary education. Confirmatory factor analysis results indicate adequate fit indexes for the one-factor solution (v2/df = 2.70, GFI = .96, CFI = .96), which showed convergent validity, reliability and homogeneity. In conclusion, there is psychometric evidence for the one-factor structure of the SWLS in Portugal.FCTCOMPET

Dimensionality and measurement invariance in the Satisfaction with Life Scale in Norway

Purpose Results from previous studies examining the dimensionality and factorial invariance of the Satisfaction with Life Scale (SWLS) are inconsistent and often based on small samples. This study examines the factorial structure and factorial invariance of the SWLS in a Norwegian sample. Methods Confirmatory factor analysis (AMOS) was conducted to explore dimensionality and test for measurement invariance in factor structure, factor loadings, intercepts, and residual variance across gender and four age groups in a large (N = 4,984), nationally representative sample of Norwegian men and women (15–79 years). Results The data supported a modified unidimensional structure. Factor loadings could be constrained to equality between the sexes, indicating metric invariance between genders. Further testing indicated invariance also at the strong and strict levels, thus allowing analyses involving group means. The SWLS was shown to be sensitive to age, however, at the strong and strict levels of invariance testing. Conclusion In conclusion, the results in this Norwegian study seem to confirm that a unidimensional structure is acceptable, but that a modified single-factor model with correlations between error terms of items 4 and 5 is preferred. Additionally, comparisons may be made between the genders. Caution must be exerted when comparing age groups

Visualizing Cholesterol in the Brain by On-Tissue Derivatization and Quantitative Mass Spectrometry Imaging.

Despite being a critical molecule in the brain, mass spectrometry imaging (MSI) of cholesterol has been under-reported compared to other lipids due to the difficulty in ionizing the sterol molecule. In the present work, we have employed an on-tissue enzyme-assisted derivatization strategy to improve detection of cholesterol in brain tissue sections. We report distribution and levels of cholesterol across specific structures of the mouse brain, in a model of Niemann-Pick type C1 disease, and during brain development. MSI revealed that in the adult mouse, cholesterol is the highest in the pons and medulla and how its distribution changes during development. Cholesterol was significantly reduced in the corpus callosum and other brain regions in the Npc1 null mouse, confirming hypomyelination at the molecular level. Our study demonstrates the potential of MSI to the study of sterols in neuroscience

Extensive microbial and functional diversity within the chicken cecal microbiome

Chickens are major source of food and protein worldwide. Feed conversion and the health of chickens relies on the largely unexplored complex microbial community that inhabits the chicken gut, including the ceca. We have carried out deep microbial community profiling of the microbiota in twenty cecal samples via 16S rRNA gene sequences and an in-depth metagenomics analysis of a single cecal microbiota. We recovered 699 phylotypes, over half of which appear to represent previously unknown species. We obtained 648,251 environmental gene tags (EGTs), the majority of which represent new species. These were binned into over two-dozen draft genomes, which included Campylobacter jejuni and Helicobacter pullorum. We found numerous polysaccharide- and oligosaccharide-degrading enzymes encoding within the metagenome, some of which appeared to be part of polysaccharide utilization systems with genetic evidence for the co-ordination of polysaccharide degradation with sugar transport and utilization. The cecal metagenome encodes several fermentation pathways leading to the production of short-chain fatty acids, including some with novel features. We found a dozen uptake hydrogenases encoded in the metagenome and speculate that these provide major hydrogen sinks within this microbial community and might explain the high abundance of several genera within this microbiome, including Campylobacter, Helicobacter and Megamonas