Sewanee: The University of the South

About: Sewanee: The University of the South is a education organization based out in Sewanee, Tennessee, United States. It is known for research contribution in the topics: Population & Species richness. The organization has 8995 authors who have published 14790 publications receiving 320138 citations. The organization is also known as: Sewanee & The University of the South.

Quantifying uncertainty in estimation of tropical arthropod species richness.

Abstract: There is a bewildering range of estimates for the number of arthropods on Earth. Several measures are based on extrapolation from species specialized to tropical rain forest, each using specific assumptions and justifications. These approaches have not provided any sound measure of uncertainty associated with richness estimates. We present two models that account for parameter uncertainty by replacing point estimates with probability distributions. The models predict medians of 3.7 million and 2.5 million tropical arthropod species globally, with 90% confidence intervals of [2.0, 7.4] million and [1.1, 5.4] million, respectively. Estimates of 30 million or greater are predicted to have <0.00001 probability. Sensitivity analyses identified uncertainty in the proportion of canopy arthropod species that are beetles as the most influential parameter, although uncertainties associated with three other parameters were also important. Using the median estimates suggests that in spite of 250 years of taxonomy and around 855,000 species of arthropods already described, approximately 70% await description.

Moorea producens gen. nov., sp. nov. and Moorea bouillonii comb. nov., tropical marine cyanobacteria rich in bioactive secondary metabolites.

Abstract: The filamentous cyanobacterial genus Moorea gen. nov., described here under the provisions of the International Code of Botanical Nomenclature, is a cosmopolitan pan-tropical group abundant in the marine benthos. Members of the genus Moorea are photosynthetic (containing phycocyanin, phycoerythrin, allophycocyanin and chlorophyll a), but non-diazotrophic (lack heterocysts and nitrogenase reductase genes). The cells (discoid and 25–80 µm wide) are arranged in long filaments (<10 cm in length) and often form extensive mats or blooms in shallow water. The cells are surrounded by thick polysaccharide sheaths covered by a rich diversity of heterotrophic micro-organisms. A distinctive character of this genus is its extraordinarily rich production of bioactive secondary metabolites. This is matched by genomes rich in polyketide synthase and non-ribosomal peptide synthetase biosynthetic genes which are dedicated to secondary metabolism. The encoded natural products are sometimes responsible for harmful algae blooms and, due to morphological resemblance to the genus Lyngbya , this group has often been incorrectly cited in the literature. We here describe two species of the genus Moorea: Moorea producens sp. nov. (type species of the genus) with 3LT as the nomenclature type, and Moorea bouillonii comb. nov. with PNG5-198R as the nomenclature type.

Nomenclatural validation of the genetically revised cyanobacterial genus Dolichospermum (RALFS ex BORNET et FLAHAULT) comb. nova.

Abstract: The traditional cyanobacterial genus Anabaena is heterogeneous, as follows from the modern molecular evaluation. The cluster of planktic Anabaena-morphotypes with gas vesicles in cells must be separated as a unique generic entity from the typical benthic mat-forming species. In the present articles all planktic morphospecies are transferred into the new genus Dolichospermum in agreement with Botanical nomenclatoric rules. The name "Dolichospermum" is based on a taxonomic category of section in starting point publication (B ornet & f la H ault 1888), which is valid for heterocytous cynobacteria.

Survivor reactions to organizational downsizing: Does time ease the pain?

Abstract: The present study used work role transitions theory as a guiding framework for examining changes in survivors' attitudes following an organizational downsizing. A total of 106 managers experiencing a downsizing provided data regarding organizational commitment, turnover intentions, job involvement, role clarity, role overload, satisfaction with top management, and satisfaction with job security at three different times. Although the results generally indicated that downsizing had a significant impact on work attitudes, that the impact varied over time, and that the initial impact was generally negative; different patterns of results among the job attitudes studied were also observed. For example, satisfaction with top management increased across time, while job involvement decreased. Findings also indicated that changes in role clarity, role overload, satisfaction with top management, and satisfaction with job security were significantly related to changes in organizational commitment and turnover intentions. Changes in job involvement also moderated several relationships such that there was a stronger relationship between the independent variable and the outcome variable when job involvement was higher than when job involvement was lower. Theoretical and practical implications of the findings and directions for future research are discussed.

Lipoxidation products as biomarkers of oxidative damage to proteins during lipid peroxidation reactions

Abstract: Oxidative stress is implicated in the pathogenesis of numerous disease processes including diabetes mellitus, atherosclerosis, ischaemia reperfusion injury and rheumatoid arthritis. Chemical modification of amino acids in protein during lipid peroxidation results in the formation of lipoxidation products which may serve as indicators of oxidative stress in vivo. The focus of the studies described here was initially to identify chemical modifications of protein derived exclusively from lipids in order to assess the role of lipid peroxidative damage in the pathogenesis of disease. Malondialdehye (MDA) and 4-hydroxynonenal (HNE) are well characterized oxidation products of polyunsaturated fatty acids on low-density lipoprotein (LDL) and adducts of these compounds have been detected by immunological means in atherosclerotic plaque. Thus, we first developed gas chromatography-mass spectrometry assays for the Schiff base adduct of MDA to lysine, the lysine-MDA-lysine diimine cross-link and the Michael addition product of HNE to lysine. Using these assays, we showed that the concentrations of all three compounds increased significantly in LDL during metal-catalysed oxidation in vitro. The concentration of the advanced glycation end-product N epsilon-(carboxymethyl)lysine (CML) also increased during LDL oxidation, while that of its putative carbohydrate precursor the Amadori compound N epsilon-(1-deoxyfructose-1-yl)lysine did not change, demonstrating that CML is a marker of both glycoxidation and lipoxidation reactions. These results suggest that MDA and HNE adducts to lysine residues should serve as biomarkers of lipid modification resulting from lipid peroxidation reactions, while CML may serve as a biomarker of general oxidative stress resulting from both carbohydrate and lipid oxidation reactions.