Is O-1(2) alone sufficient for DNA cleavage? Possible involvement of paramagnetic intermediates

It is proposed that singlet dioxygen reacting with guanosine or deoxyguanosine part of nucleotides does not, by itself, cause DNA cleavage. The strand break originates at the endoperoxide stage whenever this link evolves into a O-centered radical. The O-centered radical is then in a good spatial position to abstract an hydrogen intramolecularly from the ribose or desoxyribose part of the nucleotide. The carbon centered radical thus formed on the sugar part may lead to strand break either by a p-scission mechanism or by an homolytically induced solvolysis. High pH could also induce cleavage after the endoperoxide stage via a base catalyzed ring chain protomerism.

Averting biodiversity collapse in tropical forest protected areas

The rapid disruption of tropical forests probably imperils global biodiversity more than any other contemporary phenomenon(1-3). With deforestation advancing quickly, protected areas are increasingly becoming final refuges for threatened species and natural ecosystem processes. However, many protected areas in the tropics are themselves vulnerable to human encroachment and other environmental stresses(4-9). As pressures mount, it is vital to know whether existing reserves can sustain their biodiversity. A critical constraint in addressing this question has been that data describing a broad array of biodiversity groups have been unavailable for a sufficiently large and representative sample of reserves. Here we present a uniquely comprehensive data set on changes over the past 20 to 30 years in 31 functional groups of species and 21 potential drivers of environmental change, for 60 protected areas stratified across the world's major tropical regions. Our analysis reveals great variation in reserve `health': about half of all reserves have been effective or performed passably, but the rest are experiencing an erosion of biodiversity that is often alarmingly widespread taxonomically and functionally. Habitat disruption, hunting and forest-product exploitation were the strongest predictors of declining reserve health. Crucially, environmental changes immediately outside reserves seemed nearly as important as those inside in determining their ecological fate, with changes inside reserves strongly mirroring those occurring around them. These findings suggest that tropical protected areas are often intimately linked ecologically to their surrounding habitats, and that a failure to stem broad-scale loss and degradation of such habitats could sharply increase the likelihood of serious biodiversity declines.

Intravenous immunoglobulin expands regulatory T cells via induction of cyclooxygenase-2-dependent prostaglandin E2 in human dendritic cells

CD4(+)CD25(+)FoxP3(+) regulatory T cells (Tregs) play a critical role in the maintenance of immune tolerance. Intravenous immunoglobulin (IVIg), a therapeutic preparation of normal pooled human IgG, expands Tregs in various experimental models and in patients. However, the cellular and molecular mechanisms by which IVIg expands Tregs are relatively unknown. As Treg expansion in the periphery requires signaling by antigen-presenting cells such as dendritic cells (DCs) and IVIg has been demonstrated to modulate DC functions, we hypothesized that IVIg induces distinct signaling events in DCs that subsequently mediate Treg expansion. We demonstrate that IVIg expands Tregs via induction of cyclooxygenase (COX)-2-dependent prostaglandin E2 (PGE(2)) in human DCs. However, costimulatory molecules of DCs such as programmed death ligands, OX40 ligand, and inducible T-cell costimulator ligands were not implicated. Inhibition of PGE(2) synthesis by COX-2 inhibitors prevented IVIg-mediated Treg expansion in vitro and significantly diminished IVIg-mediated Treg expansion in vivo and protection from disease in experimental autoimmune encephalomyelitis model. IVIg-mediated COX-2 expression, PGE(2) production, and Treg expansion were mediated in part via interaction of IVIg and F(ab('))(2) fragments of IVIg with DC-specific intercellular adhesion molecule-3-grabbing nonintegrin. Our results thus uncover novel cellular and molecular mechanism by which IVIg expands Tregs.

The adenylyl cyclase Rv2212 modifies the proteome and infectivity of Mycobacterium bovis BCG

All organisms have the capacity to sense and respond to environmental changes. These signals often involve the use of second messengers such as cyclic adenosine monophosphate (cAMP). This second messenger is widely distributed among organisms and coordinates gene expression related with pathogenesis, virulence, and environmental adaptation. Genomic analysis in Mycobacterium tuberculosis has identified 16 adenylyl cyclases (AC) and one phosphodiesterase, which produce and degrade cAMP, respectively. To date, ten AC have been biochemically characterized and only one (Rv0386) has been found to be important during murine infection with M. tuberculosis. Here, we investigated the impact of hsp60-driven Rv2212 gene expression in Mycobacterium bovis Bacillus Calmette-Guerin (BCG) during growth in vitro, and during macrophage and mice infection. We found that hsp60-driven expression of Rv2212 resulted in an increased capacity of replication in murine macrophages but an attenuated phenotype in lungs and spleen when administered intravenously in mice. Furthermore, this strain displayed an altered proteome mainly affecting proteins associated with stress conditions (bfrB, groEL-2, DnaK) that could contribute to the attenuated phenotype observed in mice.

Long-term effects of Macroternies termites, herbivores and annual early fire on woody undergrowth community in Sudanian woodland, Burkina Faso

Termites, herbivores and fire are recognized as major guilds that structure woody plant communities in African savanna and woodland ecosystems. An understanding of their interaction is crucial to design appropriate management regimes. The aim of this study was to evaluate the long-term impacts of herbivore, fire and termite activities on regeneration of trees. Permanent experimental quadrats were established in 1992 in the Sudanian woodland of Burkina Faso subjected to grazing by livestock and annual early fire and the control. Within the treatment quadrats, an inventory of the woody undergrowth community was conducted on termitaria occupied by Macrotermes subhyalinus, extended termitosphere (within 5 m radius from the mound base) and adjacent area (beyond 5 m from the mound base). Hierarchical analysis was performed to determine significant differences in species richness, abundance and diversity indices among vegetation patches within fire and herbivory treatments. Grazed quadrats had significantly (P < 0.001) more species and stem density of woody undergrowth than non-grazed quadrats but maintained similar level of species richness and stem density of woody undergrowth on termitaria. There were not significant differences (P>0.05) in species richness and stem density between burnt and unburnt quadrats. Termitaria supported a highly diverse woody undergrowth with higher stem density than either the extended termitosphere or rest of quadrats. The density of woody undergrowth was significantly related with mature trees of selected species on termitaria (R-2 = 0.593; P<0.001) than that on the extended termitosphere (R-2 = 0.333; P<0.001) and adjacent area (R-2 = 0.197; P<0.001). It can be concluded that termites facilitate the regeneration of woody species while grazing and annual early fire play a minor role in the regeneration of woody species. The current policy that prohibits grazing should be revised to accommodate the interests of livestock herders. (C) 2014 Elsevier GmbH. All rights reserved.

Morphological and functional characterisation of the burrow systems of six earthworm species (Lumbricidae)

Earthworm burrow systems are generally described based on postulated behaviours associated with the three ecological types. In this study, we used X-ray tomography to obtain 3D information on the burrowing behaviour of six very common anecic (Aporrectodea nocturna and Lumbricus terrestris) and endogeic (Aporrectodea rosea, Allolobophora chlorotica, Aporrectodea caliginosa, Aporrectodea icterica) earthworm species, introduced into repacked soil cores for 6 weeks. A simple water infiltration test, the Beerkan method, was also used to assess some functional properties of these burrow systems. Endogeic worms make larger burrow systems, which are more highly branched, less continuous and of smaller diameter, than those of anecic worms. Among the anecic species, L. terrestris burrow systems are shorter (9.2 vs 21.2 m) with a higher number (14.5 vs 23.5) of less branched burrows (12.2 vs 20.2 branches m(-1)), which are also wider (7.78 vs 5.16 mm) than those of A. nocturna. In comparison, the burrow systems made by endogeic species appeared similar to each other. However, A. rosea burrows were short and narrow, whereas A. icterica had a longer burrow system (15.7 m), more intense bioturbation intensity (refilled macropores or soil lateral compaction around them) and thus a greater number of burrows. Regarding water infiltration, anecic burrow systems were far more efficient due to open burrows linking the top and bottom of the cores. For endogeic species, we observed a linear relationship between burrow length and the water infiltration rate (R (2) = 0.49, p < 0.01). Overall, the three main characteristics significantly influencing water infiltration were burrow length, burrow number and bioturbation volume. This last characteristic highlighted the effect of burrow refilling by casts.

In Situ NMR Insights into the Electrochemical Reaction of Cu3P Electrodes in Lithium Batteries

This study reports a multinuclei in situ (real-time) NMR spectroscopic characterization of the electrochemical reactions of a negative Cu3P electrode toward lithium. Taking advantage of the different nuclear spin characteristics, we have obtained real-time P-31 and Li-7 NMR data for a comprehensive understanding of the electrochemical mechanism during the discharge and charge processes of a lithium battery. The large NMR chemical shift span of P-31 facilitates the observation of the chemical evolutions of different lithiated and delithiated LixCu3-xP phases, whereas the quadrupolar line features in Li-7 enable identification of asymmetric Li sites. These combined NMR data offer an unambiguous identification of four distinct LixCu3-xP phases, Cu3P, Li0.2Cu2.8P, Li2CuP, and. Li3P, and the characterization of their involvement in the electrochemical reactions. The NMR data led us to propose a delithiation process involving the intercalation of metallic Cu-0 atomic aggregates into the Li2CuP structure to form a Cu-0-Li2-xCu1-xP phase. This process might be responsible for the poor capacity retention in Cu3P lithium batteries when cycled to a low voltage.

El lenguaje místico en Santa Catalina de Siena

Resumen: El lenguaje místico posee características propias, una de ellas es la inefabilidad. En este artículo la autora, basándose en los conceptos elaborados por M. De Certeau, analiza en primer lugar los rasgos que posee este lenguaje en la obra de Santa Catalina de Siena. En segundo lugar el artículo explora la matriz epistolar que posee Il Dialogo della Divina Provvidenza, la obra más importante de la santa. Aquí se observa de qué manera una gramática hablada conserva las entonaciones propias de la meditación que le da origen. Teniendo su origen en una carta Il Dialogo no sólo manifiesta el lenguaje oral usado en su época sino su estatuto privado y público a la vez.

Teología, 2008, Tomo XLV nº 97 (número completo)

Nota del Director -- Breve exposición de la hermenéutica analógica / Mauricio Beuchot -- ¿Fin de la antropología alma-cuerpo? / Lucio Florio -- Michel de Certeau : recorridos por el "creer" y sus constelaciones contemporáneas / Marcelo González -- Justicia, caridad y solidaridad en la DSI / Gustavo Irrazábal -- "Las palabras del Grito" / Hugo Rodolfo Safa -- Grupo de estudio bíblico judío cristiano / Víctor M. Fernández -- Una aproximación al acompañamiento espiritual en San Juan de la Cruz -- El lenguaje de la vida en la estética hildegardiana / Cecilia Inés Avenatti de Palumbo -- Reflexiones sobre la experiencia religiosa durante la crisis de identidad de la adolescencia / Julio V. Maffei -- Catalina de Siena : su teología hecha biografía / Gabriela María Di Renzo -- Espiritualidad sanante : salud y espiritualidad en Anselm Grün / Mónica Cristina Ukaski -- El legado póstumo de José Carlos Barcellos / Alberto Toutin -- Notas bibliográficas

Prudentia Iuris, 2008, n° 64-65 (número completo)

Presentación -- Parte I -- Breve relato sobre el Anticristo / Vladimir Soloiev -- Las enseñanzas de la iconografía / Marisa Mosto -- ¿Cómo se hace un ícono? / María Bargalló -- Michel Villey: Destructor de ídolos, creador de íconos / Carlos Raúl Sanz -- La racionalidad al rescate de la Naturaleza y la Ley Natural / María Celestina Donadío Maggi de Gandolfi -- Part II -- El cuadragésimo aniversario de la reforma del Código Civil (ley 17.711) /Carlos Raúl Sanz -- Parte III -- Segundo Encuentro Interuniversitario de Derecho de Familia. Controversias Jurídicas Actuales. Facultad de Derecho de la Pontificia Universidad Católica Argentina. Buenos Aires, 4 de junio de 2008 -- Los principios ético-jurídicos del vínculo paterno-filial y familiar por adopción / Catalina Elsa Arias de Ronchietto -- Democratización de la familia y su incidencia en los vínculos jurídico-familiares / Ursula C. Basset -- El derecho del niño a la familia / Julio César Capparelli -- La filiación y sus controversias jurídicas modernas. Un asunto inquietante / Ursula C. Basset -- Impugnación de la paternidad matrimonial. La exclusión de la madre y del pretenso padre biológico / Jorge Oscar Perrino -- Parte IV -- Derecho y retórica. Una aproximación desde la academia estadounidense / Valentín Thury Cornejo -- Notas sobre la asistencia social / José Benjamín Gomez Paz -- La Justicia y el derecho en el pensamiento del Santo Tomás de Aquino y Hans Kelsen / Alberto Silvio Pestalardo -- San Agustín, Dante y la Globalización. Una invitación a la reflexión sobre la globalización y la laicidad / Carlos A. Gabriel Maino -- La esclavitud en la doctrina Aristotélica-Tomista / Sebastián Pierpaulli -- Hegel y la evangelización de la cultura / María Fernanda Balmaseda Cinquina -- Parte V -- Comentarios Bibliográficos -- Parte VI -- Las Enseñanzas del Papa S.S. Benedicto XVI -- Parte VII -- Documentos