Petrological Insights into Shifts in Eruptive Styles at Volcán Llaima (Chile)

Tephra and lava pairs from two summit eruptions (ad 2008 and 1957) and a flank fissure eruption (∼ ad 1850) are compared in terms of textures, phenocryst contents, and mineral zoning patterns to shed light on processes responsible for the shifts in eruption style during typical eruptive episodes at Volcán Llaima (Andean Southern Volcanic Zone, Chile). The mineralogy and whole-rock compositions of tephra and lavas are similar within eruptive episodes, suggesting a common magma reservoir for Strombolian paroxysms and lava effusion. The zoning profiles and textures of plagioclase record successive and discrete intrusions of volatile-rich mafic magma accompanied by mixing of these recharge magmas with the resident basaltic-andesitic crystal mushes that are commonly present at shallow levels in the Llaima system. Each recharge event destabilizes the plagioclase in equilibrium with the resident crystal mush melt and stabilizes relatively An-rich plagioclase, as is recorded by the numerous resorption zones. Lavas typically have ∼15-20 vol. % more phenocrysts than the tephra. Differences in plagioclase and olivine textures and zoning, combined with different phenocryst contents, indicate that a greater volume fraction of recharge magma is present in the explosively erupted magma than in subsequent effusively erupted magma. We propose that Strombolian paroxysms at Volcán Llaima are triggered by interactions with large volume fractions of recharge magma, which decrease the bulk viscosity and increase the volatile contents of the erupted magmas, leading to the conditions required for the fragmentation of basaltic-andesite. Lava effusion ensues from reduced interactions with the recharge magma, after it has partially degassed and crystallized, thereby impeding rapid ascent. This process could be operating at other steady-state basaltic volcanoes, wherein shallow reservoirs are periodically refilled by fresh, volatile-rich magma

Ribose 2′-O-methylation provides a molecular signature for the distinction of self and non-self mRNA dependent on the RNA sensor Mda5

The 5'-cap-structures of higher eukaryote mRNAs are ribose 2'-O-methylated. Likewise, a number of viruses replicating in the cytoplasm of eukayotes have evolved 2'-O-methyltransferases to modify autonomously their mRNAs. However, a defined biological role of mRNA 2'-O-methylation remains elusive. Here we show that viral mRNA 2'-O-methylation is critically involved in subversion of type-I-interferon (IFN-I) induction. We demonstrate that human and murine coronavirus 2'-O-methyltransferase mutants induce increased IFN-I expression, and are highly IFN-I sensitive. Importantly, IFN-I induction by 2'-O-methyltransferase-deficient viruses is dependent on the cytoplasmic RNA sensor melanoma differentiation-associated gene 5 (MDA5). This link between MDA5-mediated sensing of viral RNA and mRNA 2'-O-methylation suggests that RNA modifications, such as 2'-O-methylation, provide a molecular signature for the discrimination of self and non-self mRNA

Mapping co-benefits for carbon storage and biodiversity to inform conservation policy and action

International audienceIntegrated high-resolution maps of carbon stocks and biodiversity that identify areas of potential co-benefits for climate change mitigation and biodiversity conservation can help facilitate the implementation of global climate and biodiversity commitments at local levels. However, the multi-dimensional nature of biodiversity presents a major challenge for understanding, mapping and communicating where and how biodiversity benefits coincide with climate benefits. A new integrated approach to biodiversity is therefore needed. Here, we (a) present a new high-resolution map of global above- and below-ground carbon stored in biomass and soil, (b) quantify biodiversity values using two complementary indices (BIp and BIr) representing proactive and reactive approaches to conservation, and (c) examine patterns of carbon–biodiversity overlap by identifying 'hotspots' (20% highest values for both aspects). Our indices integrate local diversity and ecosystem intactness, as well as regional ecosystem intactness across the broader area supporting a similar natural assemblage of species to the location of interest. The western Amazon Basin, Central Africa and Southeast Asia capture the last strongholds of highest local biodiversity and ecosystem intactness worldwide, while the last refuges for unique biological communities whose habitats have been greatly reduced are mostly found in the tropical Andes and central Sundaland. There is 38 and 5% overlap in carbon and biodiversity hotspots, for proactive and reactive conservation, respectively. Alarmingly, only around 12 and 21% of these proactive and reactive hotspot areas, respectively, are formally protected. This highlights that a coupled approach is urgently needed to help achieve both climate and biodiversity global targets. This would involve (1) restoring and conserving unprotected, degraded ecosystems, particularly in the Neotropics and Indomalaya, and (2) retaining the remaining strongholds of intactnes

Down-regulation of frizzled-7 expression decreases survival, invasion and metastatic capabilities of colon cancer cells

BackgroundThe canonical Wnt signalling pathway is activated in most sporadic colorectal cancers (CRCs). We previously reported that FZD7 functions as a receptor for the canonical Wnt signalling pathway in colon cancer cells.Methods and resultsIn this study, we examined the function of FZD7 in survival, invasion and metastatic capabilities of colon cancer cells. FZD7_siRNA transfection decreased cell viability of HT-29 and HCT-116 colon cancer cells. Expression of c-Jun, phosphorylation of JNK and c-Jun, and activation of RhoA were suppressed after FZD7_siRNA transfection into HCT-116 cells. In vitro invasion activity and Wnt target gene expression were also reduced in HCT-116 cells transfected with FZD7_siRNA. Liver metastasis of stable FZD7_siRNA HCT-116 cell transfectants in scid mice was decreased to 40-50% compared to controls. The mRNA levels of FZD7 in 135 primary CRC tissues were examined by real-time PCR. FZD7 mRNA levels were significantly higher in stage II, III or IV tumours than in non-tumour tissues (P<0.005), and overall survival was shorter in those patients with higher FZD7 expression (P<0.001).ConclusionThese data suggest that FZD7 may be involved in enhancement of survival, invasion and metastatic capabilities of colon cancer cells through non-canonical Wnt signalling pathways as well as the canonical pathway

Notulae to the Italian alien vascular flora: 7

In this contribution, new data concerning the distribution of vascular flora alien to Italy are presented. It includes new records, confirmations, and status changes for Italy or for Italian administrative regions of taxa in the genera Abies, Actinidia, Alooe, Amaryllis, Anredera, Arctotheca, Bidens, Cardiospermum, Celosia, Commelina, Cotoneaster, Cyclamen, Eclipta, Euphorbia, Grevillea, Hedera, Hibiscus, Impatiens, Juglans, Kalanchoe, Koelreuteria, Lindernia, Melinis, Myriophyllum, Nandina, Nicotiana, Oenothera, Oxalis, Parthenocissus, Phoenix, Phyllanthus, Physalis, Plumbago, Pteris, Quercus, Setaria, Symphytum, Tagetes, and Washingtonia. Nomenclatural and distribution updates, published elsewhere are provided as Suppl. material 1

e-Pilly TROP Maladies infectieuses tropicales

L’e-Pilly TROP est un ouvrage d’infectiologie tropicale destiné aux médecins et aux étudiants en médecine des pays francophones du Sud. La prise en compte des différents niveaux de la pyramide sanitaire dans ces pays le rend aussi accessible aux infirmiers des centres de santé communautaires urbains et des structures de santé intermédiaires des zones rurales. Par définition, les Pays En Développement accroissant progressivement leurs capacités de diagnostic biologique et de traitement, les outils de prise en charge correspondent aux moyens des niveaux périphériques comme à ceux des niveaux hospitaliers de référence