Savoirs techniques locaux, sources d'innovations ? Production de savoirs actionnables dans une démarche de recherche action en partenariat

International audienceFace aux défis auxquels l'Afrique de l'Ouest est confrontée pour son développement, les savoirs techniques locaux peuvent-ils être des sources de connaissance pour l'innovation ? Traditionnellement, les pratiques d'un groupe social sont réglées sur un long terme par les savoirs locaux jusqu'à l'avènement de problèmes inhabituels. Dans chaque nouvelle situation problématique, le retour à la maîtrise technique passe par l'acquisition de nouveaux savoirs et l'apprentissage de nouvelles pratiques, le tout s'inscrivant dans un processus d'innovation. Les démarches de recherche action en partenariat, visant à résoudre les problèmes vécus par les acteurs de terrain, requièrent la production de références actionnable. Dans ce cadre, les savoirs techniques locaux peuvent favoriser l'innovation s'ils sont réellement pris en compte. Nous proposons que dans les diagnostics, ils soient intégrés dans l'analyse des pratiques et de leurs fondements, et que dans la mise en œuvre des solutions et la conception des innovations, ils soient coalisés aux savoirs exogènes mobilisés. Cette thèse sera illustrée par des travaux de recherche en partenariat conduits, dans les villages de Koumbia et de Waly (ouest du Burkina Faso) visant la conception et la mise en œuvre d'innovations sur les pratiques de conduite des troupeaux au pâturage (élaboration de nouvelles règles) et de gestion de la fertilité des sols avec des fumures organiques (diversification et amélioration de la production)

A case report of a giant fallopian tube leiomyoma mimicking a mesenteric tumor.

Leiomyomas are benign tumors usually found in the uterus although other organs such as the vagina and the ovaries can be involved. The most common etiology of tubal disorders is infection, but tubal leiomyomas remain a rare possibility. We hereby present a case-report of fallopian tube leiomyoma undiagnosed preoperatively despite the technological progress in radiologic imaging. The diagnosis was only made at laparotomy. In this case report, diagnostic measures and the difficulties encountered are discussed.KEY WORDS: Abdominal mass- Fallopian tube fibroid - Diagnosis

Antiplasmodial activity of some phenolic compounds from Cameroonians Allanblackia

Background: Plasmodium falciparum, one of the causative agents of malaria, has high adaptability through mutation and is resistant to many types of anti-malarial drugs. This study presents an in vitro  assessment of the antiplasmodial activity of some phenolic compounds isolated from plants of the genus Allanblackia.Methods: Tests were performed on well plates filled with a fixed parasitized erythrocytes volume. Compounds to be tested were then added in wells. After incubation, tritiated hypoxanthine is added and the plates were returned to the incubator. After thawing, the nucleic acids are collected. Inhibitory Concentration 50 (IC50) was determined by linear interpolation.Results: From Allanblackia floribunda, have been isolated and characterized 1,7-dihydroxyxanthone 1, macluraxanthone 4, morelloflavone 9, Volkensiflavone 10 and morelloflavone 7-O-glucoside 11; from Allanblackia monticola, α-mangosine 2, rubraxanthone 3, allaxanthone C 5, norcowanine 6 , tovophiline A 7, allaxanthone B 8 and from Allanblackia gabonensis, 1,7-dihydroxyxanthone 1. Six of them were  evaluated for their antimalarial properties. The most active compound, macluraxanthone, presented a  very interesting activity, with an IC50 of 0.36 and 0.27 μg/mL with the F32 and FcM29 strains  respectively.Conclusion: This work confirms that species of Allanblackia genus are medicinally important plants containing many biologically active compounds that can be used effectively as antiplasmodial.Key words: Guttiferaceae, Allanblackia, Phenolic compounds, Antiplasmodial activit

Seasonal polyphenism in Bicyclus dorothea (Lepidoptera: Nymphalidae) across different habitats in Cameroon

Open Access Article; Published online: 14 Sept 2018Many organisms exhibit changes in phenotypic traits as a response to seasonal environmental variation. We investigated the role of habitat in generating seasonal polyphenism in different populations of the light bush brown butterfly Bicyclus dorothea (Cramer, 1779) (Lepidoptera: Nymphalidae) in Cameroon. Butterflies were caught during the wet and dry seasons across four localities representing two distinct habitats, namely forest and ecotone (forest–savanna transition zone) over a 2-yr period (2015–2016). We found distinct variation in the wing pattern characteristics of butterflies in response to seasonality and habitat. Specifically we observed that: 1) all wing characters are not seasonally plastic in B. dorothea; 2) populations from ecotone tend to be more variable, with individuals exhibiting wings with large spots during the wet season and very reduced spots in the dry season while in forest populations, individuals exhibit wings with large spots during the wet season, but in the dry season, spots are not as greatly reduced as their ecotone counterparts; 3) this polyphenism in B. dorothea alternated consistently during the wet and dry seasons over the 2 yr of sampling. Bicyclus species have become a textbook example of seasonal polyphenism while this study extends this model system to the unique forest–ecotone gradient of Central Africa and demonstrates the complexity of seasonal forms in different habitats

Local adaptation in thermal tolerance for a tropical butterfly across ecotone and rainforest habitats

Open Access Journal; Published online: 01 Apr 2021Thermal adaptation to habitat variability can determine species vulnerability to environmental change. For example, physiological tolerance to naturally low thermal variation in tropical forests species may alter their vulnerability to climate change impacts, compared with open habitat species. However, the extent to which habitat-specific differences in tolerance derive from within-generation versus across-generation ecological or evolutionary processes are not well characterized. Here we studied thermal tolerance limits of a Central African butterfly (Bicyclus dorothea) across two habitats in Cameroon: a thermally stable tropical forest and the more variable ecotone between rainforest and savanna. Second generation individuals originating from the ecotone, reared under conditions common to both populations, exhibited higher upper thermal limits (CTmax) than individuals originating from forest (∼3°C greater). Lower thermal limits (CTmin) were also slightly lower for the ecotone populations (∼1°C). Our results are suggestive of local adaptation driving habitat-specific differences in thermal tolerance (especially CTmax) that hold across generations. Such habitat-specific thermal limits may be widespread for tropical ectotherms and could affect species vulnerability to environmental change. However, microclimate and within-generation developmental processes (e.g. plasticity) will mediate these differences, and determining the fitness consequences of thermal variation for ecotone and rainforest species will require continued study of both within-generation and across-generation eco-evolutionary processes

The Floor Stiffness Effect on Vulnerability Assessments and Intervention Designs of Historic Buildings: the Case Study of the “Procuratie Vecchie” in Venice, Italy

In the Italian seismic scenario, and beyond, interventions on existing buildings focused on the evaluation and reduction of seismic risk of cultural heritage have gained more and more importance in the engineering field. Therefore, for the designer it becomes increasingly useful to have a methodology that allows to carry out, in the study of an existing structure behavior, the vulnerability assessment of both the actual state and the design state, evaluating the adequacy of potential intervention of seismic improvement. In this paper some phases of this methodology are presented in the context of the restoration work started in November 2017, and currently in progress, of the historical building of Procuratie Vecchie in Piazza San Marco in Venice, with particular focus on the consolidation intervention of the timber floors which satisfy the conservation requirements imposed by the Superintendence of Venice. Actually, the influence of floor diaphragms on structural behavior of existing masonry building subjected to seismic action is critically discussed with particular reference to the effects of in-plane stiffness of floors on the seismic distribution of forces on lateral walls and on the out–of–plane mechanism of the walls

Computational design of cyclic peptides for the customized oriented immobilization of globular proteins

The oriented immobilization of proteins, key for the development of novel responsive biomaterials, relies on the availability of effective probes. These are generally provided by standard approaches based on in vivo maturation and in vitro selection of antibodies and/or aptamers. These techniques can suffer technical problems when a non-immunogenic epitope needs to be targeted. Here we propose a strategy to circumvent this issue by in silico design. In our method molecular binders, in the form of cyclic peptides, are computationally evolved by stochastically exploring their sequence and structure space to identify high-affinity peptides for a chosen epitope of a target globular protein: here a solvent-exposed site of β2-microglobulin (β2m). Designed sequences were screened by explicit solvent molecular dynamics simulations (MD) followed by experimental validation. Five candidates gave dose-response surface plasmon resonance signals with dissociation constants in the micromolar range. One of them was further analyzed by means of isothermal titration calorimetry, nuclear magnetic resonance, and 250 ns of MD. Atomic-force microscopy imaging showed that this peptide is able to immobilize β2m on a gold surface. In short, we have shown by a variety of experimental techniques that it is possible to capture a protein through an epitope of choice by computational design

Maximum entropy modeling of giant pangolin Smutsia gigantea (Illiger, 1815) habitat suitability in a protected forest-savannah transition area of central Cameroon

Across the planet, biodiversity is facing ever-growing threats including habitat loss, climate change, overexploitation, and pollution. Pangolins of the order Pholidota are the only scaly mammal species worldwide and are considered the most trafficked wild mammals in the world, being widely exploited for their meat and scales. The giant pangolin (Smutsia gigantea, GP) is one of the least studied species of this order, with little being known about their response to environmental and anthropogenic variables, as well as their distribution patterns in forest-savannah transition areas. Our study aimed to increase ecological knowledge about GP by investigating the environmental factors associated with the distribution of suitable habitat for GP within a protected forest/savannah transition area of Cameroon. Using data on the locations of GP resting burrows collected using line transects and employing a maximum entropy (MaxEnt) modelling approach, we explored GP habitat suitability within a forest-savannah transition area of Cameroon. Our model revealed a good level of accuracy based on the average test area under the Receiver Operator Curve metric. The jackknife test found that Euclidian distance to the national park’s boundaries, normalized difference vegetation index, elevation, and distance to river were the most important predictors determining the distribution of GP burrows. Areas predicted to be suitable for GP burrows were patchily distributed within dense forests, ecotone and savannah, with 19.24% of the study area being suitable and 1% very suitable. Overall, our study shows the possible importance of habitat suitability modeling for understanding GP distribution, as well as planning and prioritising their conservation actions