Compositional turnover and variation in Eemian pollen sequences in Europe

Vegetation History and Archaeobotany - The Eemian interglacial represents a natural experiment on how past vegetation with negligible human impact responded to amplified temperature changes...     

A new alpinumisoflavone derivative from Genista pichisermolliana

The aerial parts of Genista pichisermolliana Valsecchi (Fabaceae), an endemic plant of Sardinia, were extracted in Soxhlet apparatus and purified by several chromatographic methods. The new compound alpinumisoflavone 4′-O-glucopyranoside (6) was isolated together with nineteen flavonoids, p-coumaric methylester and d-pinitol, while no alkaloids were detected. All the chemical structures were elucidated by spectroscopic analysis. Since flavonoids represent the main constituents of this plant, the total flavonoid content was determined according to the Italian Pharmacopoeia IX Ed. method.     

The primordial metabolism: an ancestral interconnection between leucine,arginine, and lysine biosynthesis

Background

It is generally assumed that primordial cells had small genomes with simple genes coding for enzymes able to react with a wide range of chemically related substrates, interconnecting different metabolic routes. New genes coding for enzymes with a narrowed substrate specificity arose by paralogous duplication(s) of ancestral ones and evolutionary divergence. In this way new metabolic pathways were built up by primordial cells. Useful hints to disclose the origin and evolution of ancestral metabolic routes and their interconnections can be obtained by comparing sequences of enzymes involved in the same or different metabolic routes. From this viewpoint, the lysine, arginine, and leucine biosynthetic routes represent very interesting study-models. Some of the lys, arg and leu genes are paralogs; this led to the suggestion that their ancestor genes might interconnect the three pathways. The aim of this work was to trace the evolutionary pathway leading to the appearance of the extant biosynthetic routes and to try to disclose the interrelationships existing between them and other pathways in the early stages of cellular evolution.

Results

The comparative analysis of the genes involved in the biosynthesis of lysine, leucine, and arginine, their phylogenetic distribution and analysis revealed that the extant metabolic "grids" and their interrelationships might be the outcome of a cascade of duplication of ancestral genes that, according to the patchwork hypothesis, coded for unspecific enzymes able to react with a wide range of substrates. These genes belonged to a single common pathway in which the three biosynthetic routes were highly interconnected between them and also to methionine, threonine, and cell wall biosynthesis. A possible evolutionary model leading to the extant metabolic scenarios was also depicted.

Conclusion

The whole body of data obtained in this work suggests that primordial cells synthesized leucine, lysine, and arginine through a single common metabolic pathway, whose genes underwent a set of duplication events, most of which can have predated the appearance of the last common universal ancestor of the three cell domains (Archaea, Bacteria, and Eucaryotes). The model proposes a relative timing for the appearance of the three routes and also suggests a possible evolutionary pathway for the assembly of bacterial cell-wall.

     

A high field NMR study of the products ensuing from konjak glucomannan C(6)-oxidation followed by enzymatic C(5)-epimerization

Konjak glucomannan (KGM) is a water-soluble linear copolymer of (1-->4) linked beta-D-mannopyranosyl and beta-D-glucopyranosyl units. It has been selectively C6-oxidized by a 2,2,6,6-tetramethylpiperidin-1-oxy mediated reaction to obtain the corresponding uronan. Oxidized KGM has been treated with three different C-5 epimerases, AlgE4, AlgE6, and AlgE1, to obtain uronans with a various content of alpha-L-gulopyranuronate residues, namely, KGME4, KGME6, and KGME1. By use of 1D selective and 2D NMR techniques, a full assignment of the high field (600 MHz) NMR spectra of the purified native KGM and of the oxidized and epimerized derivatives has been obtained. Since in the anomeric region of the (1)H NMR spectrum of native KGM, diads sensitivity is present, the glucose-glucose, glucose-mannose, mannose-mannose, and mannose-glucose distribution has been obtained. In the (13)C spectrum of oxidized KGM, due to the presence of triad sensitivity on the C-4 resonance of glucuronic and mannuronic units, a better sequential investigation has been possible. As a result the average length of mannuronic blocks, N(M) is obtained. When AlgE4, AlgE6, and AlgE1 enzymes are used for the epimerization of oxidized KGM, the reaction products differ significantly both in the proportion and in the distribution of the mannuronic and guluronic residues. In epimerized KGM derivatives, a careful deconvolution of (1)H spectra allows the measurement of the degree of epimerization. In the case of KGME1 and KGME6, the average blocks length, N(G), of the guluronic blocks introduced in the polysaccharidic chain with the epimerization has also been calculated. Due to the shortness of mannuronic blocks in the oxidized KGM before the epimerization, N(G) in the epimerized compounds is also very low.     

Molecular characterization of cytotoxic and resistance mechanisms induced by NCX 4040, a novel NO-NSAID, in pancreatic cancer cell lines*

Although non steroidal antiinflammatory drugs (NSAIDs) have been shown to be effective as chemopreventive agents, important side-effects limit their clinical use. A promising novel class of drugs, nitric oxide-donating NSAIDs (NO-NSAIDs), has been found to be more active than classical NSAIDs. This study explored the effect of the NO-donating aspirin derivative, NCX 4040, on three human pancreatic adenocarcinoma cell lines (Capan-2, MIA PaCa-2 and T3M4). NCX 4040 activity was compared with that of NCX 4016 (an NO₂-positional isomer of NCX 4040), SNAP (a standard NO-releasing molecule), NCX 4042 (denitrated analog of NCX 4040), and aspirin. NCX 4040 showed a striking cytocidal activity in all cell lines, already inducing significant percentages of apoptotic cells at 10 μM in Capan-2 cell lines. This study focused on the biological mechanisms of sensitivity and resistance to NCX 4040, highlighting that the cytotoxic action of this drug may be due to the hyperexpression of Bax, its translocation to the mitochondria, the release of Cytochrome C, and the activation of caspases-9 and -3, overall in a p53-independent manner. Moreover, the use of a specific COX-2 inhibitor (NS 398) in the experimental models showed that COX-2 hyperexpression could partially explain the resistance mechanisms to NCX 4040. This study was supported by Istituto Oncologico Romagnolo, Forlì, and by the Italian, Ministry of Health, 2004.     

Characterization of the first eukaryotic cold-adapted patatin-like phospholipase from the psychrophilic Euplotes focardii: Identification of putative determinants of thermal-adaptation by comparison with the homologous protein from the mesophilic Euplotes crassus

The ciliated protozoon Euplotes focardii, originally isolated from the coastal seawaters of Terra Nova Bay in Antarctica, shows a strictly psychrophilic phenotype, including optimal survival and multiplication rates at 4–5 °C. This characteristic makes E. focardii an ideal model species for identifying the molecular bases of cold adaptation in psychrophilic organisms, as well as a suitable source of novel cold-active enzymes for industrial applications. In the current study, we characterized the patatin-like phospholipase from E. focardii (EfPLP), and its enzymatic activity was compared to that of the homologous protein from the mesophilic congeneric species Euplotes crassus (EcPLP). Both EfPLP and EcPLP have consensus motifs conserved in other patatin-like phospholipases.     

Factors Affecting Work Ability in Day and Shift‐Working Nurses

Satisfactory work ability is sustained and promoted by good physical and mental health and by favorable working conditions. This study examined whether favorable and rewarding work‐related factors increased the work ability among European nurses. The study sample was drawn from the Nurses' Early Exit Study and consisted of 7,516 nursing staff from seven European countries working in state‐owned and private hospitals. In all, 10.8% were day, 4.2% were permanent night, 20.9% were shift without night shift, and 64.1% were shift workers with night shifts. Participants were administered a composite questionnaire at baseline (Time 0) and 1 yr later (Time 1). The Work Ability Index (WAI) at Time 1 was used as the outcome measure, while work schedule, sleep, rewards (esteem and career), satisfaction with pay, work involvement and motivation, and satisfaction with working hours at Time 0 were included as potential determinants of work ability. Univariate and multivariate analyses were conducted after adjusting for a number of confounders (i.e., country, age, sex, type of employment, family status, and other job opportunities in the same area). Work schedule was not related to Time 1 changes in WAI. Higher sleep quality and quantity and more favorable psychosocial factors significantly increased work ability levels. Higher sleep quality and quantity did not mediate the effect of work schedule on work ability. No relevant interaction effects on work ability were observed between work schedule and the other factors considered at Time 0. As a whole, sleep and satisfaction with working time were gradually reduced from day work to permanent night work. However, scores on work involvement, motivation, and satisfaction with pay and rewards were the highest in permanent night workers and the lowest in rotating shift workers that included night shifts.