116 research outputs found
Clinical outcome of skin yaws lesions after treatment with benzathinebenzylpenicillin in a pygmy population in Lobaye, Central African Republic
<p>Abstract</p> <p>Background</p> <p>Yaws is a bacterial skin and bone infectious disease caused by <it>Treponema pallidum pertenue</it>. It is endemic, particularly among pygmies in Central African Republic. To assess the clinical cure rate after treatment with benzathinepenicillin in this population, we conducted a cohort survey of 243 patients in the Lobaye region.</p> <p>Findings and conclusion</p> <p>The rate of healing of lesions after 5 months was 95.9%. This relatively satisfactory level of therapeutic response implies that yaws could be controlled in the Central African Republic. Thus, reinforcement of the management of new cases and of contacts is suggested.</p
Winter weather controls net influx of atmospheric CO2 on the north-west European shelf
Shelf seas play an important role in the global carbon cycle, absorbing atmospheric carbon dioxide (CO2) and exporting carbon (C) to the open ocean and sediments. The magnitude of these processes is poorly constrained, because observations are typically interpolated over multiple years. Here, we used 298500 observations of CO2 fugacity (fCO2) from a single year (2015), to estimate the net influx of atmospheric CO2 as 26.2 ± 4.7 Tg C yr-1 over the open NW European shelf. CO2 influx from the atmosphere was dominated by influx during winter as a consequence of high winds, despite a smaller, thermally-driven, air-sea fCO2 gradient compared to the larger, biologically-driven summer gradient. In order to understand this climate regulation service, we constructed a carbon-budget supplemented by data from the literature, where the NW European shelf is treated as a box with carbon entering and leaving the box. This budget showed that net C-burial was a small sink of 1.3 ± 3.1 Tg C yr-1, while CO2 efflux from estuaries to the atmosphere, removed the majority of river C-inputs. In contrast, the input from the Baltic Sea likely contributes to net export via the continental shelf pump and advection (34.4 ± 6.0 Tg C yr-1)
The Submarine Volcano Eruption off El Hierro Island: Effects on the Scattering Migrant Biota and the Evolution of the Pelagic Communities
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Dengue Virus Infection of Aedes aegypti Requires a Putative Cysteine Rich Venom Protein
Citation: Londono-Renteria, B., Troupin, A., Conway, M. J., Vesely, D., Ledizet, M., Roundy, C. M., . . . Colpitts, T. M. (2015). Dengue Virus Infection of Aedes aegypti Requires a Putative Cysteine Rich Venom Protein. Plos Pathogens, 11(10), 23. doi:10.1371/journal.ppat.1005202Dengue virus (DENV) is a mosquito-borne flavivirus that causes serious human disease and mortality worldwide. There is no specific antiviral therapy or vaccine for DENV infection. Alterations in gene expression during DENV infection of the mosquito and the impact of these changes on virus infection are important events to investigate in hopes of creating new treatments and vaccines. We previously identified 203 genes that were >= 5-fold differentially upregulated during flavivirus infection of the mosquito. Here, we examined the impact of silencing 100 of the most highly upregulated gene targets on DENV infection in its mosquito vector. We identified 20 genes that reduced DENV infection by at least 60% when silenced. We focused on one gene, a putative cysteine rich venom protein (SeqID AAEL000379; CRVP379), whose silencing significantly reduced DENV infection in Aedes aegypti cells. Here, we examine the requirement for CRVP379 during DENV infection of the mosquito and investigate the mechanisms surrounding this phenomenon. We also show that blocking CRVP379 protein with either RNAi or specific antisera inhibits DENV infection in Aedes aegypti. This work identifies a novel mosquito gene target for controlling DENV infection in mosquitoes that may also be used to develop broad preventative and therapeutic measures for multiple flaviviruses
Disease: A Hitherto Unexplored Constraint on the Spread of Dogs (Canis lupus familiaris) in Pre-Columbian South America
Although debate continues, there is agreement that dogs (Canis lupus familiaris) were first domesticated in Eurasia, spreading from there to other parts of the world. However, while that expansion already extended as far as Europe, China, and North America by the early Holocene, dogs spread into (and south of) the tropics only much later. In South America, for example, the earliest well attested instances of their presence do not reach back much beyond 3000 cal. BC, and dogs were still absent from large parts of the continent – Amazonia, the Gran Chaco, and much of the Southern Cone – at European contact. Previous explanations for these patterns have focused on cultural choice, the unsuitability of dogs for hunting certain kinds of tropical forest prey, and otherwise unspecified environmental hazards, while acknowledging that Neotropical lowland forests witness high rates of canine mortality. Building on previous work in Sub-Saharan Africa (Mitchell 2015) and noting that the dog’s closest relatives, the grey wolf (C. lupus) and the coyote (C. latrans), were likewise absent from South and most of Central America in Pre- Columbian times, this paper explores instead the possibility that infectious disease constrained the spread of dogs into Neotropical environments. Four diseases are considered, all likely to be native and/or endemic to South America: canine distemper, canine trypanosomiasis, canine rangeliosis, and canine visceral leishmaniasis caused by infection with Leishmania amazonensis and L. colombiensis. The paper concludes by suggesting ways in which the hypothesis that disease constrained the expansion of dogs into South America can be developed further
Etat actuel des recherches sur la flore et la végétation du Rwanda et du Burundi
THE PRESENT STATE OF RESEARCH ON THE FLORA AND VEGETATION OF RWANDA ANDBURUNDI
At the end of the last century, many explorers, mainly Germans, travelled in Burundi searching for the famous sources of the Nile and the legendary ‘Mountains of the Moon. ’ Apart from the very often accurate descriptions of the vegetation and flora they encountered, one is indebted to them for the rich harvest of specimens collected, many of which were destroyed in the bombing of Berlin in 1944-1945.
When, in 1919, Burundi was placed under Belgian mandate, Belgian botanists took over the work and collected numerous specimens in the country. Their expeditions were organized from Zaire and were often of short duration, with the result that in 1965 there was still no systematic exploration of the country and in 1964 AETFAT classified Burundi as one of the lesser known areas in Africa.
Systematic exploration of the country began in 1965 with J. Lewalle. Apart from the publication of an excellent work on the stratification of the vegetation, he collected more than 6 500 numbers of herbarium specimens, several of which represented new species. He worked in Burundi until 1972.
From 1970 to 1980, Reekmans collected more than 9 500 specimens for the herbarium, mainly in the areas that were not intensively explored previously. He has published several works in connection with the phenology o f species and vegetation association of western Burundi.
Many botanists invited by Lewalle and Reekmans, have had the opportunity to explore the country and to collect specimens of special groups.
At present, it can be said that, except for a very small area of the country (otherwise well known in Rwanda where several studies have been made) the flora of Burundi is now well known. Phytogeographical limits are well established and the publication of a vegetation map is due in the near future. A catalogue of the country’s flora is also to be published shortly.
Apart from these ‘scientific’ results, botanical studies in Burundi have also had the result of awakening the authorities to the ‘value’ of their natural heritage — to such an extent that in March 1980 a National Institute of Nature Conserx’ation was created. Its first aim will be to ensure the establishment of natural parks and several natural reserves in which some very interesting species will be preserved
Data from: Genetic evidence for a Janzen-Connell recruitment pattern in reproductive offspring of Pinus halepensis trees.
Effective seed dispersal, combining both dispersal and post-dispersal (establishment) processes, determines population dynamics and colonization ability in plants. According to the Janzen-Connell (JC) model, high mortality near the mother plant shifts the offspring establishment distribution farther away from the mother plant relative to the seed dispersal distribution. Yet, extending this prediction to the distribution of mature (reproductive) offspring remains a challenge for long-living plants. To address this challenge we selected an isolated natural Aleppo pine (Pinus halepensis) population in Mt. Pithulim (Israel), expanded from five ancestor trees in the beginning of the 20th century into ~2000 trees today. Using nine microsatellite markers, we assigned parents to trees established during the early stages of population expansion. To elucidate the effect of the distance from mother plant on post-dispersal survival, we compared the effective seed dispersal kernel, constructed based on the distribution of mother-offspring distances, to the seed dispersal kernel, computed based on simulations of a mechanistic wind dispersal model. We found that the mode of the effective dispersal kernel is shifted farther away than the mode of the seed dispersal kernel, reflecting increased survival with increasing distance from the mother plant. The parentage analysis demonstrated a highly skewed reproductive success and a strong directionality in effective dispersal corresponding to the wind regime. We thus provide the first evidence that JC effects act also on offspring that become reproductive and persisted as adults for many decades, a key requirement in assessing the role of post-dispersal processes in shaping population and community dynamics
Combined use of glider, radar and altimetry data to study a coastal current in the western Mediterranean Sea
Trabajo presentado en la Assembly of the European Geophysical Society, celebrada en Viena, Austria, del 27 de abril al 2 de mayo de 2014Peer Reviewe
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