West Nile virus genome with glycosylated envelope protein and deletion of alpha helixes 1, 2 and 4 in the capsid gene is non-infectious and efficiently secretes sub-viral particles

Flavivirus genomes with deletions in the capsid (C) gene are attractive vaccine candidates, as they secrete highly immunogenic subviral particles (SVPs) without generating infectious virus. Here, we report that cytomegalovirus promoter-driven cDNA of West Nile virus Kunjin (KUNV) containing a glycosylation motif in the envelope (E) gene and a combined deletion of alpha helices 1, 2, and 4 in C produces significantly more SVPs than KUNV cDNAs with nonglycosylated E and various other deletions in C

Electromagnetic and geochemical methods applied to investigations of hydrothermal/volcanic unrests: Examples of Taal (Philippines) and Miyake-jima (Japan) volcanoes

Magnetic, -electric and -electromagnetic phenomena (EM) are almost always observed on volcanoes before and during volcanic eruptions, if EM methods are well-designed and applied on the field. But unfortunately these methods are, most often, still used independently. They also do not benefit of dense inter-correlated networks which should allow more accurate results and fine modelling of the volcanic activity. On volcanoes which display hydrothermal/magmatic unrests, EM methods can be combined with geochemical (GC) methods. The integration of these methods allows us to image in detail hydrothermal systems, to find out possible scenarios of volcanic unrest, and to monitor the on-going activity with some knowledge on the sources of heat, gas and fluid transfers. The objectives of this paper is (1) to outline the appearance and the characteristics of EM signals before an eruptive event when multi-EM methods are applied on the field, (2) to sketch out the complementary between EM and GC methods when these methods are jointly applied on volcanic/hydrothermal systems. Two case studies are given in the paper. On Miyake-jima volcano in Japan integrated EM methods started in 1995. Although the seismicity only appeared 13 days before the July 8, 2000 collapse of the summit, changes in the magnetic field, electrical resistivity and electric potential have progressively appeared after 1996. Based on geophysical observations and on continuous magnetotelluric soundings, a synthesis of the EM observations allows proposing a coherent model of the volcano unrest. The second case study is Taal volcano in Philippines on which sporadic, but sometimes intense, seismic crises are observed since 1992. A strong and large scale hydrothermal system stands on the volcano and is periodically re-activated. Commonly applied since 2005, combined EM and GC methods give an accurate description of the hydrothermal activity and heat discharge. EM methods, as magnetic and self-potential, map the hydrothermal system and locate the source of thermal and fluid transfers at depth, while soil degassing and thermal imageries clearly point out the location of the most active areas where thermal discharges take place. GC methods also specify the origin of the gas and fluids escaping from faults, fumaroles, and geothermal areas. Between 2005 and 2007, no large change in the hydrothermal activity took place, in spite of sporadic seismic swarms and surface activities which could lead to sudden phreatic explosions. The heat discharge of the volcano is estimated and monitored with time, based on repeated surveys. Such combined EM and GC methods are now integrated in the monitoring of the slow unrest of the volcano. © 2008 Elsevier Ltd. All rights reserved.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Atmosphere-land surface interactions and their influence on extreme rainfall and potential abrupt climate change over southern Africa

In a changing climate, changes in rainfall variability and, in particular, extreme rainfall events are likely to be highly significant for environmentally vulnerable regions such as southern Africa. It is generally accepted that sea-surface temperatures play an important role in modulating rainfall variability, thus the majority work to date has focused on these mechanisms. However past research suggests that land surface processes are also critical for rainfall variability. In particular, work has suggested that the atmosphere-land surface feedback has been important for past abrupt climate changes, such as those which occurred over the Sahara during the mid-Holocene or, more recently, the prolonged Sahelian drought. Therefore the primary aim of this work is to undertake idealised experiments using both a regional and global climate model, to test the sensitivity of rainfall variability to land surface changes over a location where such abrupt climate changes are projected to occur in the future, namely southern Africa. In one experiment, the desert conditions currently observed over southwestern Africa were extended to cover the entire subcontinent. This is based on past research which suggests a remobilisation of sand dune activity and spatial extent under various scenarios of future anthropogenic global warming. In the second experiment, savanna conditions were imposed over all of southern Africa, representing an increase in vegetation for most areas except the equatorial regions. The results suggest that a decrease in rainfall occurs in the desert run, up to 27% of total rainfall in the regional model (relative to the control), due to a reduction in available moisture, less evaporation, less vertical uplift and therefore higher near surface pressure. This result is consistent across both the regional and global model experiments. Conversely an increase in rainfall occurs in the savanna run, because of an increase in available moisture giving an increase in latent heat and therefore surface temperature, increasing vertical uplift and lowering near surface pressure. These experiments, however, are only preliminary, and form the first stage of a wider study into how the atmosphere-land surface feedback influences rainfall extremes over southern Africa in the past (when surface i.e. vegetation conditions were very different) and in the future under various scenarios of future climate change. Future work will examine how other climate models simulate the atmosphere-land surface feedback, using more realistic vegetation types based on past and future surface conditions

Arboviruses of Oceania

Arboviruses present an ongoing challenge to Oceanic nations. Viruses including Ross River, Barmah Forest and Murray Valley encephalitis are endemic to the region and are responsible for occasional outbreaks. Recent epidemics of chikungunya, Zika and dengue viruses across many nations demonstrate the vulnerability of this region to globally emergent arboviruses. In addition to global disease trends, the emergence of these viruses is largely driven by human influences such as water and waste management, air travel and land use. Limited public health resources and infrastructure, dispersed populations and the complexity of arbovirus ecologies complicate mitigation and management strategies in the Western Pacific. A regional collaborative approach augments the surveillance and response capability of individual nations, but the challenge of managing arbovirus risk with limited resources remains. In the absence of specific disease treatments and feasible vaccination solutions, mosquito control and personal protective measures are the mainstay of management programmes, albeit with variable success. In the long term, the development and integration of novel surveillance, diagnostic and mosquito control technologies will improve the capacity to prevent and respond to arbovirus threats