Detection of Leishmania RNA virus in Leishmania parasites.

BACKGROUND Patients suffering from cutaneous leishmaniasis (CL) caused by New World Leishmania (Viannia) species are at high risk of developing mucosal (ML) or disseminated cutaneous leishmaniasis (DCL). After the formation of a primary skin lesion at the site of the bite by a Leishmania-infected sand fly, the infection can disseminate to form secondary lesions. This metastatic phenotype causes significant morbidity and is often associated with a hyper-inflammatory immune response leading to the destruction of nasopharyngeal tissues in ML, and appearance of nodules or numerous ulcerated skin lesions in DCL. Recently, we connected this aggressive phenotype to the presence of Leishmania RNA virus (LRV) in strains of L. guyanensis, showing that LRV is responsible for elevated parasitaemia, destructive hyper-inflammation and an overall exacerbation of the disease. Further studies of this relationship and the distribution of LRVs in other Leishmania strains and species would benefit from improved methods of viral detection and quantitation, especially ones not dependent on prior knowledge of the viral sequence as LRVs show significant evolutionary divergence. METHODOLOGY/PRINCIPAL FINDINGS This study reports various techniques, among which, the use of an anti-dsRNA monoclonal antibody (J2) stands out for its specific and quantitative recognition of dsRNA in a sequence-independent fashion. Applications of J2 include immunofluorescence, ELISA and dot blot: techniques complementing an arsenal of other detection tools, such as nucleic acid purification and quantitative real-time-PCR. We evaluate each method as well as demonstrate a successful LRV detection by the J2 antibody in several parasite strains, a freshly isolated patient sample and lesion biopsies of infected mice. CONCLUSIONS/SIGNIFICANCE We propose that refinements of these methods could be transferred to the field for use as a diagnostic tool in detecting the presence of LRV, and potentially assessing the LRV-related risk of complications in cutaneous leishmaniasis.

El bebé y el agua de la bañera o ¿aún contra la literatura? (in/comodidades de las nuevas agendas)

La instalación de los estudios culturales como práctica dominante en diversas zonas del mundo universitario ha traído como consecuencia la suspensión o incluso el olvido de proyectos que en los años 70 y 80 constituyeron una ruptura epistemológica respecto de la tradición de la crítica literaria latinoamericana. Tendencias del culturalismo actual -la crítica genealógica, los estudios subalternos- han cuestionado de tal modo la literatura como objeto de estudio que propician su desaparición de las nuevas agendas críticas. La revisión de algunos problemas que surgen de tal deseo se hará a partir de un par de textos de Alberto Moreiras y John Beverley.

El bebé y el agua de la bañera o ¿aún contra la literatura? (in/comodidades de las nuevas agendas)

La instalación de los estudios culturales como práctica dominante en diversas zonas del mundo universitario ha traído como consecuencia la suspensión o incluso el olvido de proyectos que en los años 70 y 80 constituyeron una ruptura epistemológica respecto de la tradición de la crítica literaria latinoamericana. Tendencias del culturalismo actual -la crítica genealógica, los estudios subalternos- han cuestionado de tal modo la literatura como objeto de estudio que propician su desaparición de las nuevas agendas críticas. La revisión de algunos problemas que surgen de tal deseo se hará a partir de un par de textos de Alberto Moreiras y John Beverley.

EPICA Dome C Ice Core 800KYr deuterium data and temperature estimates

A high-resolution deuterium profile is now available along the entire European Project for Ice Coring in Antarctica Dome C ice core, extending this climate record back to marine isotope stage 20.2, ~800,000 years ago. Experiments performed with an atmospheric general circulation model including water isotopes support its temperature interpretation. We assessed the general correspondence between Dansgaard-Oeschger events and their smoothed Antarctic counterparts for this Dome C record, which reveals the presence of such features with similar amplitudes during previous glacial periods. We suggest that the interplay between obliquity and precession accounts for the variable intensity of interglacial periods in ice core records. Temperature was estimated after correction for sea-water isotopic composition (Bintanja et al, 2005) and for ice sheet elevation (Parrenin et al, 2007) on EDC3 age scale (Parrenin et al, 2007).

El bebé y el agua de la bañera o ¿aún contra la literatura? (in/comodidades de las nuevas agendas)

La instalación de los estudios culturales como práctica dominante en diversas zonas del mundo universitario ha traído como consecuencia la suspensión o incluso el olvido de proyectos que en los años 70 y 80 constituyeron una ruptura epistemológica respecto de la tradición de la crítica literaria latinoamericana. Tendencias del culturalismo actual -la crítica genealógica, los estudios subalternos- han cuestionado de tal modo la literatura como objeto de estudio que propician su desaparición de las nuevas agendas críticas. La revisión de algunos problemas que surgen de tal deseo se hará a partir de un par de textos de Alberto Moreiras y John Beverley.

Nd concentrations and isotopic composition in the western Mediterranean Sea

The concentration and isotopic composition of Nd in water and particles collected in the western Mediterranean Sea are studied by two complementary approaches. The first examines local vertical profiles and time series; the second considers the global Nd budget of the whole western Mediterranean Sea. These two approaches are used to quantify the Nd inputs and the dissolved/particulate exchange processes in the water column. Two profiles of Nd in seawater in the Ligurian Sea taken in May and October 1992 show an average epsilon-Nd(0) = -9.6 ± 0.5. Seawater from the Strait of Sicily, representative of the eastern waters flowing into the western basin, is more radiogenic [epsilon-Nd(0) = -7.7 ± 0.6]. Profiles of particulate matter collected in sediment traps in coastal (Gulf of Lions) and offshore (Ligurian Sea) environments are also shown. Particles are enriched in Nd and are more radiogenic near the coast than offshore. Measurements of Nd concentration and epsilon-Nd(0) of external sources to the western Mediterranean Sea compared with the literature data demonstrate that particulate flux of atmospheric Saharan origin are more rich ([Nd] = 38 ± 10 µg/g) and less radiogenic [epsilon-Nd(0) = -13.0 ± 1.0] than riverine particulate discharge ([Nd] = 21.5 ± 4.4 µg/g; epsilon-Nd(0) = -10.1 ± 0.5), allowing to trace Nd particulate inputs in the water column. Nd atmospheric flux appears to be the major source into the whole western basin, although lateral advection of riverine material is the prevailing process in the coastal environment. Offshore, the vertical propagation of an important Saharan dust event has been recorded for two months in sediment traps at 80, 200 and 1000 m. The evolution of the resulting negative epsilon-Nd(0) peak along depth and time shows that the particles reach 200 m on a time scale of one week. For the first time, the Nd budget in the western Mediterranean basin is constrained by both concentrations and isotopic compositions measured in particles and seawater. Surface budget requires a remobilization of 30 ± 20% of particulate Nd input. In deep water, dissolved Nd concentrations are balanced by a scavenging of 10 ± 20% of the sinking particulate flux. On the other hand, the deep isotopic compositions suggest an exchange between 30 ± 20% of the sinking particles and the deep waters. The hypothesis of a non-stationary regime for the surface waters in the Ligurian Sea is also considered.