Cordyla pinnata améliore les propriétés du sol et la productivité des cultures

Dans les systèmes agroforestiers, les cultures sous le couvert des arbres (SC) bénéficient de plus de nutriments, après décomposition et minéralisation des litières, que celles hors de leur couvert (HC). La fertilité des sols et la productivité du mil et de l’arachide ont été évaluées sur des sols prélevés à différentes distances de Cordyla pinnata, une légumineuse arborée qui forme un parc agroforestier au Sénégal. Les analyses de sols ont montré des valeurs plus élevées pour N total, Ca échangeable et CEC sous le couvert de l’espèce. Pour le mil, la hauteur, les biomasses aérienne et racinaire ont également été plus élevées sur les sols SC. Par conséquent, la biomasse totale du mil a fortement augmenté (+ 90%) sur les sols SC. Pour l’arachide, la longueur totale, les biomasses (tiges, feuilles, gousses, racines) ont été supérieures sur les sols SC. Comme pour le mil, la biomasse totale de l’arachide a augmenté (+ 94%) sur les sols SC par rapport au découvert. La plupart des variables des cultures ont été plus élevées sur les sols SC, probablement à cause de leur meilleur statut nutritif. L’introduction des arbres dans les systèmes de production au Sahel pourrait ainsi constituer une bonne stratégie pour améliorer la fertilité des sols et contribuer au développement d’une agriculture durable.Mots clés: Arachide, Fertilité des sols, Mil, Parc agroforestier, Sénéga

Rift Valley fever outbreak, Mauritania, 1998: seroepidemiologic, virologic, entomologic, and zoologic investigations.

A Rift Valley fever outbreak occurred in Mauritania in 1998. Seroepidemiologic and virologic investigation showed active circulation of the Rift Valley fever virus, with 13 strains isolated, and 16% (range 1.5%-38%) immunoglobulin (Ig) M-positivity in sera from 90 humans and 343 animals (sheep, goats, camels, cattle, and donkeys). One human case was fatal

Evolution of malaria mortality and morbidity after the emergence of chloroquine resistance in Niakhar, Senegal

Background: Recently, it has been assumed that resistance of Plasmodium to chloroquine increased malaria mortality. The study aimed to assess the impact of chemoresistance on mortality attributable to malaria in a rural area of Senegal, since the emergence of resistance in 1992, whilst chloroquine was used as first-line treatment of malaria, until the change in national anti-malarial policy in 2003. Methods: The retrospective study took place in the demographic surveillance site (DSS) of Niakhar. Data about malaria morbidity were obtained from health records of three health care facilities, where diagnosis of malaria was based on clinical signs. Source of data concerning malaria mortality were verbal autopsies performed by trained fieldworkers and examined by physicians who identified the probable cause of death. Results: From 1992 to 2004, clinical malaria morbidity represented 39% of total morbidity in health centres. Mean malaria mortality was 2.4 parts per thousand and 10.4 parts per thousand among total population and children younger than five years, respectively, and was highest in the 1992-1995 period. It tended to decline from 1992 to 2003 (Trend test, total population p = 0.03, children 0-4 years p = 0.12 - children 1-4 years p = 0.04 - children 5-9 years p = 0.01). Conclusion: Contrary to what has been observed until 1995, mortality attributable to malaria did not continue to increase dramatically in spite of the growing resistance to chloroquine and its use as first-line treatment until 2003. Malaria morbidity and mortality followed parallel trends and rather fluctuated accordingly to rainfall

COIL: a methodology for evaluating malarial complexity of infection using likelihood from single nucleotide polymorphism data.

International audienceComplex malaria infections are defined as those containing more than one genetically distinct lineage of Plasmodium parasite. Complexity of infection (COI) is a useful parameter to estimate from patient blood samples because it is associated with clinical outcome, epidemiology and disease transmission rate. This manuscript describes a method for estimating COI using likelihood, called COIL, from a panel of bi-allelic genotyping assays. COIL assumes that distinct parasite lineages in complex infections are unrelated and that genotyped loci do not exhibit significant linkage disequilibrium. Using the population minor allele frequency (MAF) of the genotyped loci, COIL uses the binomial distribution to estimate the likelihood of a COI level given the prevalence of observed monomorphic or polymorphic genotypes within each sample. COIL reliably estimates COI up to a level of three or five with at least 24 or 96 unlinked genotyped loci, respectively, as determined by in silico simulation and empirical validation. Evaluation of COI levels greater than five in patient samples may require a very large collection of genotype data, making sequencing a more cost-effective approach for evaluating COI under conditions when disease transmission is extremely high. Performance of the method is positively correlated with the MAF of the genotyped loci. COI estimates from existing SNP genotype datasets create a more detailed portrait of disease than analyses based simply on the number of polymorphic genotypes observed within samples. The capacity to reliably estimate COI from a genome-wide panel of SNP genotypes provides a potentially more accurate alternative to methods relying on PCR amplification of a small number of loci for estimating COI. This approach will also increase the number of applications of SNP genotype data, providing additional motivation to employ SNP barcodes for studies of disease epidemiology or control measure efficacy. The COIL program is available for download from GitHub, and users may also upload their SNP genotype data to a web interface for simple and efficient determination of sample COI

Trends in malaria morbidity following the introduction of artesunate plus amodiaquine combination in M'lomp village dispensary, south-western Senegal

BACKGROUND: In Thailand, South Africa and Zanzibar, a decrease in malaria morbidity was observed following the introduction of artemisinin-based combination therapy (ACT). In Senegal, therapeutic trials supervised the in vivo efficacy of artesunate plus amodiaquine from 1999 to 2005 at the M'lomp village dispensary. The trends in malaria morbidity in this village were evaluated from 2000 to 2002. METHODS: Each year, between July and December inclusive, fevers treated with antimalarials and slide-proven, uncomplicated malaria cases were collected from dispensary health records. Data were also collected in 1998, just prior to ACT introduction. Pearson's chi square tests and Student tests were used to compare two percentages or two means respectively (alpha = 0.05). RESULTS: Between 1998 and 2002, the total number of fevers treated with antimalarials and their repetitiveness progressively decreased: From 2824 to 945 fevers and from 17.6% to 9.7% (RR1998-2002 = 0.55; [0.44-0.69]; p < 0.0001) respectively. Considering uncomplicated malaria cases only, a decrease was observed in their total number between 2001 and 2002, from 953 to 570 cases. The incidence rate and repetitiveness also decreased. The incidence rate fell from 46.1% in 2001 to 37.5% in 2002 (p < 0.0001) and the repetitiveness decreased from 13.0% in 2000 to 6.6% in 2002 (RR2000-2002 = 0.51; [0.35-0.72]; p = 0.0001). CONCLUSION: The percentage of uncomplicated malaria cases treated with ACT increased, from 18.9% in 2000 to 64.0% in 2002, making it tempting to conclude an impact on malaria morbidity. Nonetheless, the decline in incidence rate of uncomplicated malaria was slight and a lower recorded rainfall was reported in 2002 which could also explain this decline. The context in which ACT is introduced affects the impact on malaria morbidity. In M'lomp, in contrast to studies in Thailand, South Africa and Zanzibar, ACT coverage of malaria cases was low and no vector control measure was deployed. Moreover, the malaria transmission level is higher. In sub-Saharan countries, in order to optimize the impact on malaria morbidity, ACT deployment must be supported, on the one hand, by a strengthening of public health system to ensure a high ACT coverage and, on the other hand, by others measures, such vector control measures

Consumer responses and willingness-to-pay for hibiscus products: A preliminary study

The rise in diseases like obesity and diabetes is a worldwide challenge. The consumption of functional products such as hibiscus, which has been proven to be high in bioactive compounds and dietary fiber, providing it with anticancer, antiaging, anti-inflammatory and satiety properties, should be promoted. In the U.S., promoting the consumption of hibiscus products can be a good approach to increase fiber consumption and to reduce risk of obesity, diabetes, and hypertension. However, information about knowledge of this functional product among consumers is still sparse and increasing consumption requires designing and marketing desired products made from hibiscus. Therefore in this preliminary study, we assessed consumer response to hibiscus products and investigated whether providing information about potential health benefits could impact consumer willingness-to-pay (WTP) for three types of non-alcoholic hibiscus beverages: ready-made tea, bottled juice, and kombucha. Our web-based survey was distributed through QualtricsXM and a convenience sampling method was chosen. Most participants identified themselves as female, 18–34 years old, with a graduate degree. Most participants (81%) had consumed hibiscus products before and 57% had a weekly food budget lower than $60. Overall, tea and juices were the most liked hibiscus beverages, respectively. Although taste and health benefits were ranked as the main reasons to consume hibiscus beverages, additional information about hibiscus health benefits did not significantly affect WTP for these products. Without additional health benefit information, consumer WTP for non-alcoholic hibiscus beverages ranged from$2.9 to $3.60 for kombucha and$4.08–4.97 for Ready-made-tea. This study provides valuable insights that can support future research on hibiscus products and promote the development of novel hibiscus-based foods and beverages that are appealing to the U.S. market

Sequence-Based Association and Selection Scans Identify Drug Resistance Loci in the Plasmodium Falciparum Malaria Parasite

Through rapid genetic adaptation and natural selection, the Plasmodium falciparum parasite—the deadliest of those that cause malaria—is able to develop resistance to antimalarial drugs, thwarting present efforts to control it. Genome-wide association studies (GWAS) provide a critical hypothesis-generating tool for understanding how this occurs. However, in P. falciparum, the limited amount of linkage disequilibrium hinders the power of traditional array-based GWAS. Here, we demonstrate the feasibility and power improvements gained by using whole-genome sequencing for association studies. We analyzed data from 45 Senegalese parasites and identified genetic changes associated with the parasites’ in vitro response to 12 different antimalarials. To further increase statistical power, we adapted a common test for natural selection, XP-EHH (cross-population extended haplotype homozygosity), and used it to identify genomic regions associated with resistance to drugs. Using this sequence-based approach and the combination of association and selection-based tests, we detected several loci associated with drug resistance. These loci included the previously known signals at pfcrt, dhfr, and pfmdr1, as well as many genes not previously implicated in drug-resistance roles, including genes in the ubiquitination pathway. Based on the success of the analysis presented in this study, and on the demonstrated shortcomings of array-based approaches, we argue for a complete transition to sequence-based GWAS for small, low linkage-disequilibrium genomes like that of P. falciparum.Molecular and Cellular BiologyOrganismic and Evolutionary Biolog

PATOGENICIDADE DE ESPÉCIES DE Macrophomina COLETADAS DE PLANTAS DANINHAS EM FEIJÃO-CAUPI

[PT] A podridão de carvão causada por Macrophomina phaseolina é uma das principais doenças do feijão-caupi, causando perdas substanciais para os produtores. Na região semiárida do Brasil, o feijão-caupi é uma das alternativas utilizadas para rotação de culturas durante a entressafra do melão. Isso favorece a multiplicação de Macrophomina, uma vez que ambas as culturas são hospedeiras desse patógeno. O objetivo deste estudo foi verificar a patogenicidade em caupi de Macrophomina phaseolina e M. pseudophaseolina em caupi. Isolados de Macrophomina spp. obtidos das raízes de Trianthema portulacastrum e Boerhavia diffusa, espécies de plantas daninhas prevalentes em áreas de produção de melão no Nordeste brasileiro foram utilizadas neste estudo. O experimento foi realizado em casa de vegetação. Plantas de feijão-caupi 'Paulistinha' foram inoculados com 30 isolados de M. phaseolina, 30 isolados de M. pseudophaseolina e um isolado de referência de M. phaseolina obtido de raízes de feijão-caupi. Todos os isolados de Macrophomina foram patogênicos ao feijão-caupi, não havendo diferenças estatísticas entre as duas espécies de Macrophomina em relação à incidência e severidade da doença. Além disso, 65,2 e 100,0% dos isolados de M. phaseolina, e 56,2 e 92,8% dos isolados de M. pseudophaseolina, obtidos de T. portulacastrum e B. diffusa, respectivamente, foram tão severos ao feijão-caupi quanto o isolado de referência. Esses resultados enfatizam a necessidade de estabelecer práticas de manejo visando o controle de T. portucalastrum e B. diffusa nas áreas de produção de feijão-caupi, pois podem atuar como fontes de inóculo e sobrevivência para Macrophomina spp.[EN] Charcoal rot caused by Macrophomina phaseolina is a major cowpea disease causing substantial losses to growers. In the semi-arid region of Brazil, cowpea is one of the most widely used alternatives for crop rotation during the off-season of melon. This favors Macrophomina multiplication because both crops are hosts of this pathogen. The objective of this study was to verify the pathogenicity of Macrophomina phaseolina and M. pseudophaseolina on cowpea. The Macrophomina spp. isolates used were obtained from the roots of Trianthema portulacastrum and Boerhavia diffusa, weed species prevalent in melon production areas in North-east Brazilian The experiment was carried out in a greenhouse. Cowpea plants cv. Paulistinha' were inoculated with 30 M. phaseolina isolates, 30 M. pseudophaseolina isolates and a reference isolate of H. phaseolina obtained from cowpea roots. All Macrophomina isolates were able to cause disease on cowpea and there were no statistical differences between both Macrophomina species regarding disease incidence and severity. Moreover, 65.2 and 100.0% of the M. phaseolina isolates, and 56.2 and 92.8% of the M. pseudophaseolina isolates, obtained from T. portulacastrum and B. diffusa, respectively, were as severe to cowpea as the M. phaseolina reference isolate from cowpea. These results emphasize the need to establish management practices aiming to control T. portucalastrum and B. diffusa from cowpea production areas, as they can act as potential sources of inoculum and survival for Macrophomina spp.This study was partially financed by the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior -Brazil (CAPES) -Finance Code 001 and by the Conselho Nacional de desenvolvimento Cientifico e Tecnologico (CNPq).Sales Jr., R.; Nogueira, A.; Mitsa Paiva Negreiros, A.; Rodrigues, T.; De Queiroz, M.; Armengol Fortí, J. (2020). PATHOGENICITY OF Macrophomina SPECIES COLLECTED FROM WEEDS IN COWPEA. Revista Caatinga. 33(2):395-401. https://doi.org/10.1590/1983-21252020v33n212rcS395401332Ambrósio, M. M. Q., Dantas, A. C. A., Martínez-Perez, E., Medeiros, A. C., Nunes, G. H. S., & Picó, M. B. (2015). Screening a variable germplasm collection of Cucumis melo L. for seedling resistance to Macrophomina phaseolina. Euphytica, 206(2), 287-300. doi:10.1007/s10681-015-1452-xFreitas, F. C. L., Medeiros, V. F. L. P., Grangeiro, L. C., Silva, M. G. O., Nascimento, P. G. M. L., & Nunes, G. H. (2009). Interferência de plantas daninhas na cultura do feijão-caupi. Planta Daninha, 27(2), 241-247. doi:10.1590/s0100-83582009000200005Gomes-Silva, F., Almeida, C. M. A., Silva, A. G., Leão, M. P. C., Silva, K. P., Oliveira, L. G., … Lima, V. L. M. (2017). Genetic Diversity of Isolates of Macrophomina phaseolina Associated with Cowpea from Brazil Semi-Arid Region. Journal of Agricultural Science, 9(11), 112. doi:10.5539/jas.v9n11p112Gupta, G. K., Sharma, S. K., & Ramteke, R. (2012). Biology, Epidemiology and Management of the Pathogenic Fungus Macrophomina phaseolina (Tassi) Goid with Special Reference to Charcoal Rot of Soybean (Glycine max (L.) Merrill). Journal of Phytopathology, 160(4), 167-180. doi:10.1111/j.1439-0434.2012.01884.xKaur, S., Dhillon, G. S., Brar, S. K., Vallad, G. E., Chand, R., & Chauhan, V. B. (2012). Emerging phytopathogenMacrophomina phaseolina: biology, economic importance and current diagnostic trends. Critical Reviews in Microbiology, 38(2), 136-151. doi:10.3109/1040841x.2011.640977Machado, A. R., Pinho, D. B., Soares, D. J., Gomes, A. A. M., & Pereira, O. L. (2018). Bayesian analyses of five gene regions reveal a new phylogenetic species of Macrophomina associated with charcoal rot on oilseed crops in Brazil. European Journal of Plant Pathology, 153(1), 89-100. doi:10.1007/s10658-018-1545-1Mbaye, N., Mame, P. S., Ndiaga, C., & Ibrahima, N. (2015). Is the recently described Macrophomina pseudophaseolina pathogenically different from Macrophomina phaseolina? African Journal of Microbiology Research, 9(45), 2232-2238. doi:10.5897/ajmr2015.7742Negreiros, A. M. P., Sales Júnior, R., León, M., Melo, N. J., Michereff, S. J., Ambrósio, M. M., … Armengol, J. (2019). Identification and pathogenicity of Macrophomina species collected from weeds in melon fields in Northeastern Brazil. Journal of Phytopathology, 167(6), 326-337. doi:10.1111/jph.12801Negreiros, A. M. P., Júnior, R. S., Rodrigues, A. P. M. S., León, M., & Armengol, J. (2019). Prevalent weeds collected from cucurbit fields in Northeastern Brazil reveal new species diversity in the genusMonosporascus. Annals of Applied Biology, 174(3), 349-363. doi:10.1111/aab.12493Ramos, H. M. M., Bastos, E. A., Andrade Júnior, A. S. de, & Marouelli, W. A. (2012). Estratégias ótimas de irrigação do feijão‑caupi para produção de grãos verdes. Pesquisa Agropecuária Brasileira, 47(4), 576-583. doi:10.1590/s0100-204x2012000400014Reis, E. M., Boaretto, C., & Danelli, A. L. D. (2014). Macrophomina phaseolina: density and longevity of microsclerotia in soybean root tissues and free on the soil, and competitive saprophytic ability. Summa Phytopathologica, 40(2), 128-133. doi:10.1590/0100-5405/1921Rocha, M. de M., Carvalho, K. J. M. de, Freire Filho, F. R., Lopes, Â. C. de A., Gomes, R. L. F., & Sousa, I. da S. (2009). Controle genético do comprimento do pedúnculo em feijão-caupi. Pesquisa Agropecuária Brasileira, 44(3), 270-275. doi:10.1590/s0100-204x2009000300008Sales Junior, R., Oliveira, O. F. de, Medeiros, É. V. de, Guimarães, I. M., Correia, K. C., & Michereff, S. J. (2012). Ervas daninhas como hospedeiras alternativas de patógenos causadores do colapso do meloeiro. Revista Ciência Agronômica, 43(1), 195-198. doi:10.1590/s1806-66902012000100024Sales Júnior, R., Rodrigues, A. P. M. dos S., Negreiros, A. M. P., Ambrósio, M. M. de Q., Barboza, H. da S., & Beltrán, R. (2019). WEEDS AS POTENTIAL HOSTS FOR FUNGAL ROOT PATHOGENS OF WATERMELON. Revista Caatinga, 32(1), 1-6. doi:10.1590/1983-21252019v32n101rcFrancisco, de A. S. e S., & Carlos, A. V. de A. (2016). The Assistat Software Version 7.7 and its use in the analysis of experimental data. African Journal of Agricultural Research, 11(39), 3733-3740. doi:10.5897/ajar2016.11522Silva, M. G. O. da, Freitas, F. C. L. de, Negreiros, M. Z. de, Mesquita, H. C. de, Santana, F. A. O. de, & Lima, M. F. P. de. (2013). Manejo de plantas daninhas na cultura da melancia nos sistemas de plantio direto e convencional. Horticultura Brasileira, 31(3), 494-499. doi:10.1590/s0102-05362013000300025Zhao, L., Cai, J., He, W., & Zhang, Y. (2019). Macrophomina vaccinii sp. nov. causing blueberry stem blight in China. MycoKeys, 55, 1-14. doi:10.3897/mycokeys.55.3501

Identification and Functional Validation of the Novel Antimalarial Resistance Locus PF10_0355 in Plasmodium falciparum

The Plasmodium falciparum parasite's ability to adapt to environmental pressures, such as the human immune system and antimalarial drugs, makes malaria an enduring burden to public health. Understanding the genetic basis of these adaptations is critical to intervening successfully against malaria. To that end, we created a high-density genotyping array that assays over 17,000 single nucleotide polymorphisms (~1 SNP/kb), and applied it to 57 culture-adapted parasites from three continents. We characterized genome-wide genetic diversity within and between populations and identified numerous loci with signals of natural selection, suggesting their role in recent adaptation. In addition, we performed a genome-wide association study (GWAS), searching for loci correlated with resistance to thirteen antimalarials; we detected both known and novel resistance loci, including a new halofantrine resistance locus, PF10_0355. Through functional testing we demonstrated that PF10_0355 overexpression decreases sensitivity to halofantrine, mefloquine, and lumefantrine, but not to structurally unrelated antimalarials, and that increased gene copy number mediates resistance. Our GWAS and follow-on functional validation demonstrate the potential of genome-wide studies to elucidate functionally important loci in the malaria parasite genome.Bill & Melinda Gates FoundationEllison Medical FoundationExxon Mobil FoundationFogarty International CenterNational Institute of Allergy and Infectious Diseases (U.S.)Burroughs Wellcome FundDavid & Lucile Packard FoundationNational Science Foundation (U.S.). Graduate Research Fellowship Progra