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31.
Emmanuel Amoah Boakye Aster Gebrekirstos Dibi N’da Hyppolite Victor Rex Barnes François N. Kouamé Daouda Kone Stefan Porembski Achim Bräuning 《Trees - Structure and Function》2016,30(5):1695-1709
Key message
The paper demonstrates the prospects and applications of dendrochronology for understanding climate change effects on riparian forests in the savanna landscape.Abstract
Riparian trees in savannas have a potential for dendro-climatic studies, but have been neglected hitherto. We examined ring-width series of Afzelia africana (evergreen) and Anogeissus leiocarpus (deciduous) to study the influence of climatic factors on the growth of riparian trees in the humid (HS) and dry (DS) savanna zones of the Volta basin in Ghana. A total of 31 stem discs belonging to A. africana and A. leiocarpus were selected from HS and DS to establish species-specific local chronologies of tree growth. Each individual of A. africana and A. leiocarpus from the two savanna sites showed distinct growth rings. Cross-dating of individual tree-ring patterns was successful using standard dendrochronological techniques. The mean annual growth rates of A. africana in the HS (1.38 ± 0.09) and DS (1.34 ± 0.08) were not statistically different. Furthermore, mean annual growth rate of A. leiocarpus in the DS (3.75 ± 0.27) was higher than in the HS (2.83 ± 0.16) suggesting that species in drier environment can have higher growth rates when sufficient soil moisture is available. The growth rates of both species at the same sites were different, which might indicate different water use strategies. High correlations of individual tree-ring series of A. africana and A. leiocarpus trees at HS and DS suggest a strong climatic forcing controlled by the seasonal movement of the inter-tropical convergence zone. The annual growth of A. africana and A. leiocarpus at both the HS and DS was significantly correlated with local temperature and precipitation. The negative correlations of the growth of the two tree species to global sea surface temperatures were however, indications that the growth of riparian forests can be impacted during El Niño-Southern Oscillation years. The result of our study shows that riparian trees in the humid and dry savanna zones of West Africa can be successfully used for dendrochronological studies.32.
Pierre Walet N'Guessan Ahoua Yapi Franois Kouam N'Guessan Norbert N'Dri Kouam Christiane Nathalie Gouamen Romain Aka Aka Klotioloma Coulibaly Mathias Gnion Tahi Boak Kon Emmanuel Koffi Kassin Evelyne Marise Assi Brigitte Honorine Sahin Boguinard Guiraud Alain Acka Jacques Kotaix 《Journal of Applied Entomology》2019,143(10):1065-1071
From 2013 to 2018, surveys were conducted in counties not previously surveyed in order to determine species of mealybugs present in the cocoa orchard in Côte d'Ivoire as well as their abundance according to the age of cocoa trees. Immature and mature cocoa trees were inspected to hand‐height in 5 and 29 counties infected with Cacao swollen shoot virus (CSSV). In each cocoa farm, mealybugs were searched for on fruits, leaves, flowers, twigs and trunks. Mealybug species were identified, and colonies were counted. Five mealybug species were identified on immature cocoa trees: Ferrisia virgata, Formicococcus njalensis, Planococcus citri, Planococcus kenyae and Pseudococcus longispinus. In addition to these species, four species, Dysmicoccus brevipes, Maconellicoccus hirsutus, Phenacoccus hargreavesi and Pseudococcus jackbeardsleyi were identified on mature cocoa trees. On immature cocoa trees, Fo. Njalensis, Pl. citri and Ps. longispinus comprised were, respectively, 35%, 33% and 19% of colonies, respectively. On mature cocoa trees, Fo. Njalensis and Pl. citri comprised 63.2% and 21.0%, and others species 15.8%. Nevertheless, the abundance of mealybug species varied according to the age of cocoa trees. The preferred organs of mealybugs were pods (74.1%) followed by twigs (13.4%) and flowers (7.4%). Previously, the mealybug Paracoccus burnerae (Brain) was found on Theobroma cacao, which is the first record for this species in Côte d'Ivoire and on this host‐plant. 相似文献
33.
Coulibaly MB Lobo NF Fitzpatrick MC Kern M Grushko O Thaner DV Traoré SF Collins FH Besansky NJ 《PloS one》2007,2(9):e849
The malaria vector Anopheles gambiae maintains high levels of inversion polymorphism that facilitate its exploitation of diverse ecological settings across tropical Africa. Molecular characterization of inversion breakpoints is a first step toward understanding the processes that generate and maintain inversions. Here we focused on inversion 2Rj because of its association with the assortatively mating Bamako chromosomal form of An. gambiae, whose distinctive breeding sites are rock pools beside the Niger River in Mali and Guinea. Sequence and computational analysis of 2Rj revealed the same 14.6 kb insertion between both breakpoints, which occurred near but not within predicted genes. Each insertion consists of 5.3 kb terminal inverted repeat arms separated by a 4 kb spacer. The insertions lack coding capacity, and are comprised of degraded remnants of repetitive sequences including class I and II transposable elements. Because of their large size and patchwork composition, and as no other instances of these insertions were identified in the An. gambiae genome, they do not appear to be transposable elements. The 14.6 kb modules inserted at both 2Rj breakpoint junctions represent low copy repeats (LCRs, also called segmental duplications) that are strongly implicated in the recent (approximately 0.4N(e) generations) origin of 2Rj. The LCRs contribute to further genome instability, as demonstrated by an imprecise excision event at the proximal breakpoint of 2Rj in field isolates. 相似文献
34.
Natalya Lukoyanova Stephanie C. Kondos Irene Farabella Ruby H. P. Law Cyril F. Reboul Tom T. Caradoc-Davies Bradley A. Spicer Oded Kleifeld Daouda A. K. Traore Susan M. Ekkel Ilia Voskoboinik Joseph A. Trapani Tamas Hatfaludi Katherine Oliver Eileen M. Hotze Rodney K. Tweten James C. Whisstock Maya Topf Helen R. Saibil Michelle A. Dunstone 《PLoS biology》2015,13(2)
Membrane attack complex/perforin-like (MACPF) proteins comprise the largest superfamily of pore-forming proteins, playing crucial roles in immunity and pathogenesis. Soluble monomers assemble into large transmembrane pores via conformational transitions that remain to be structurally and mechanistically characterised. Here we present an 11 Å resolution cryo-electron microscopy (cryo-EM) structure of the two-part, fungal toxin Pleurotolysin (Ply), together with crystal structures of both components (the lipid binding PlyA protein and the pore-forming MACPF component PlyB). These data reveal a 13-fold pore 80 Å in diameter and 100 Å in height, with each subunit comprised of a PlyB molecule atop a membrane bound dimer of PlyA. The resolution of the EM map, together with biophysical and computational experiments, allowed confident assignment of subdomains in a MACPF pore assembly. The major conformational changes in PlyB are a ∼70° opening of the bent and distorted central β-sheet of the MACPF domain, accompanied by extrusion and refolding of two α-helical regions into transmembrane β-hairpins (TMH1 and TMH2). We determined the structures of three different disulphide bond-trapped prepore intermediates. Analysis of these data by molecular modelling and flexible fitting allows us to generate a potential trajectory of β-sheet unbending. The results suggest that MACPF conformational change is triggered through disruption of the interface between a conserved helix-turn-helix motif and the top of TMH2. Following their release we propose that the transmembrane regions assemble into β-hairpins via top down zippering of backbone hydrogen bonds to form the membrane-inserted β-barrel. The intermediate structures of the MACPF domain during refolding into the β-barrel pore establish a structural paradigm for the transition from soluble monomer to pore, which may be conserved across the whole superfamily. The TMH2 region is critical for the release of both TMH clusters, suggesting why this region is targeted by endogenous inhibitors of MACPF function. 相似文献
35.
36.
Estimating the Local Value of Non-Timber Forest Products to Pendjari Biosphere Reserve Dwellers in Benin 总被引:1,自引:0,他引:1
Fifanou G. Vodouhê Ousmane Coulibaly Charlotte Greene Brice Sinsin 《Economic botany》2009,63(4):397-412
Estimating the Local Value of Non-Timber Forest Products to Pendjari Biosphere Reserve Dwellers in Benin. This paper uses an indices method based on participant ranking of species to quantify use–values of Non-Timber Forest Products
(NTFPs) and the socio-economic factors that influence these values for people living around the Pendjari Biosphere Reserve
in Benin. There were 76 species identified that had a high index value to people. The 10 most valued species were Parkia biglobosa, Adansonia digitata, Vitellaria paradoxa, Tamarindus indica, Lannea microcarpa, Vitex doniana, Hibiscus asper, Melochia corchorifolia, Khaya senegalensis, and Diospyros mespiliformis. Species values were influenced by the vegetative form of the species as well as by the gender of a participant and his/her
affiliation to the ethnic group. The study also illustrates that women had a preference for NTFP species with high commercial
and nutritional values, while men preferred plants that provide construction material and medicine. Moreover, the ethnic group
that historically had more contact and interaction with the vegetation valued NTFPs more than any other group. The difference
in value attributed to species by people was also driven by the vertical transmission of ethnobotanical knowledge in the study
area. For long-term biodiversity conservation, it will be useful to involve the needs of all of the local communities in the
design of a management plan and focus attention on the most important species. 相似文献
37.
Boubacar Coulibaly Augustin Zoungrana Frank P. Mockenhaupt R. Heiner Schirmer Christina Klose Ulrich Mansmann Peter E. Meissner Olaf Müller 《PloS one》2009,4(5)
Background
With the availability of new preventive and curative interventions, global malaria control has been strengthened significantly in recent years. Drugs effective in reducing malaria gametocytaemia might contribute to local elimination and possible long-term eradication. We here report on the effects of methylene blue (MB)-based malaria combination therapy on gametocytaemia during a randomised-controlled trial in Burkina Faso.Methods
An open-label randomised controlled phase II study in 180 children aged 6–10 years with uncomplicated falciparum malaria was conducted in Nouna, north-western Burkina Faso. Children were randomised to MB–artesunate (AS), MB–amodiaquine (AQ), and AS-AQ (local standard of care). Overall follow-up was for 28 days, follow-up for gametocytaemia was for 14 days.Findings
The treatment groups were similar in baseline characteristics and there was only one loss to follow-up. Compared to AS-AQ, both MB-containing regimens were associated with significantly reduced gametocyte carrier rates during follow-up days 3, 7, and 14. This effect was seen both in patients with and without P. falciparum gametocytaemia at baseline.Interpretation
MB reveals pronounced gametocytocidal activity which appears to act against both existing and developing P. falciparum gametocytes. MB-based combination therapy thus has the potential to reduce transmission of P. falciparum malaria in endemic regions, which has important implications for future elimination and eradication strategies.Trial Registration
ClinicalTrials.gov NCT00354380相似文献38.
Archie C. A. Clements Elisa Bosqué-Oliva Moussa Sacko Aly Landouré Robert Dembélé Mamadou Traoré Godefroy Coulibaly Albis F. Gabrielli Alan Fenwick Simon Brooker 《PLoS neglected tropical diseases》2009,3(5)
Background
We investigated changes in the spatial distribution of schistosomiasis in Mali following a decade of donor-funded control and a further 12 years without control.Methodology/Principal Findings
National pre-intervention cross-sectional schistosomiasis surveys were conducted in Mali in 1984–1989 (in communities) and again in 2004–2006 (in schools). Bayesian geostatistical models were built separately for each time period and on the datasets combined across time periods. In the former, data from one period were used to predict prevalence of schistosome infections for the other period, and in the latter, the models were used to determine whether spatial autocorrelation and covariate effects were consistent across periods. Schistosoma haematobium prevalence was 25.7% in 1984–1989 and 38.3% in 2004–2006; S. mansoni prevalence was 7.4% in 1984–1989 and 6.7% in 2004–2006 (note the models showed no significant difference in mean prevalence of either infection between time periods). Prevalence of both infections showed a focal spatial pattern and negative associations with distance from perennial waterbodies, which was consistent across time periods. Spatial models developed using 1984–1989 data were able to predict the distributions of both schistosome species in 2004–2006 (area under the receiver operating characteristic curve was typically >0.7) and vice versa.Conclusions/Significance
A decade after the apparently successful conclusion of a donor-funded schistosomiasis control programme from 1982–1992, national prevalence of schistosomiasis had rebounded to pre-intervention levels. Clusters of schistosome infections occurred in generally the same areas accross time periods, although the precise locations varied. To achieve long-term control, it is essential to plan for sustainability of ongoing interventions, including stengthening endemic country health systems. 相似文献39.
Fabiano Oliveira Seydou Doumbia Jennifer M. Anderson Ousmane Faye Souleymane S. Diarra Pierre Traoré Moumine Cisse Guimba Camara Koureissi Tall Cheick A. Coulibaly Sibiry Samake Ibrahim Sissoko Bourama Traoré Daouda Diallo Somita Keita Rick M. Fairhurst Jesus G. Valenzuela Shaden Kamhawi 《PLoS neglected tropical diseases》2009,3(12)
Apart from a single report, the last publication of cutaneous leishmaniasis (CL) in Mali dates back more than 20 years. The absence of information on the current status of CL in Mali led us to conduct a cohort study in Kemena and Sougoula, two villages in Central Mali from which cases of CL have been recently diagnosed by Mali''s reference dermatology center in Bamako. In May 2006, we determined the baseline prevalence of Leishmania infection in the two villages using the leishmanin skin test (LST). LST-negative individuals were then re-tested over two consecutive years to estimate the annual incidence of Leishmania infection. The prevalence of Leishmania infection was significantly higher in Kemena than in Sougoula (45.4% vs. 19.9%; OR: 3.36, CI: 2.66–4.18). The annual incidence of Leishmania infection was also significantly higher in Kemena (18.5% and 17% for 2007 and 2008, respectively) than in Sougoula (5.7% for both years). These data demonstrate that the risk of Leishmania infection was stable in both villages and confirm the initial observation of a significantly higher risk of infection in Kemena (OR: 3.78; CI: 2.45–6.18 in 2007; and OR: 3.36; CI: 1.95–5.8 in 2008; P<0.005). The absence of spatial clustering of LST-positive individuals in both villages indicated that transmission may be occurring anywhere within the villages. Although Kemena and Sougoula are only 5 km apart and share epidemiologic characteristics such as stable transmission and random distribution of LST-positive individuals, they differ markedly in the prevalence and annual incidence of Leishmania infection. Here we establish ongoing transmission of Leishmania in Kemena and Sougoula, Central Mali, and are currently investigating the underlying factors that may be responsible for the discrepant infection rates we observed between them.
Trial Registration
ClinicalTrials.gov NCT00344084相似文献40.
Caird Rexroad Roger Vallejo Issa Coulibaly Charlene Couch Amber Garber Mark Westerman Craig Sullivan 《Conservation Genetics》2006,7(6):971-982
Striped bass (Morone saxatilis) is economically important in the US due to its value as an aquaculture species and in supporting commercial and recreational fisheries, especially those off the Atlantic coast and in the Gulf of Mexico. Modern strategies for managing fishery populations and aquaculture broodstocks employ the use of molecular genetic markers to identify individuals, assign parentage, and characterize population genetic structure and levels of inbreeding and migration. As part of a collaborative effort to utilize molecular genetic technologies in striped bass breeding programs we generated microsatellite markers for use in population genetic studies, broodstock selection and management strategies, and the construction of a genetic map. We developed 345 new microsatellite markers for striped bass, a subset (n=71) of which was characterized by genotyping samples from two striped bass broodstock populations to evaluate marker polymorphism, percent heterozygosity, Hardy–Weinberg equilibrium (HWE), linkage disequilibrium (LD) and utility for population genetic studies. 相似文献