Assessing Farmers' Diverse Preferences and Expectations for Tailoring Food and Nutrition Security Interventions in Southeastern Madagascar.

Background: Severe food and nutrition insecurity persists in Madagascar. The Atsimo Atsinanana region is among the most affected areas due to elevated poverty rates and low levels of resilience to frequent shocks. Implementing food and nutrition security (FNS) interventions could help to improve this situation, but to be effective and sustainable, intervention packages must fit the local context. Objectives: To identify locally suitable options, this study assessed the perceptions of local communities in rural Atsimo Atsinanana toward a range of FNS intervention options. Methods: We held 12 gender-disaggregated workshops with 80 prospective beneficiaries of an FNS project, from inland and coastal parts of the region. Preferences were elicited for 14 potential FNS interventions. Next, through participatory ex ante impact assessment, participants ranked 8 impact criteria and individually estimated expected impacts of all intervention options on these criteria. Results: Overall, participants preferred interventions targeting on-farm crop, vegetable, and livestock production. Income and food self-sufficiency were ranked as the highest intervention priorities. However, intervention preferences differed by gender and geographic location. Whereas preferences for interventions targeting dietary habits were weak across genders, women had relatively stronger preferences for these interventions than men. This shows that collecting gender-disaggregated preferences can enable more gender-sensitive choice of interventions. Preferences also reflected local livelihoods, as more market-oriented coastal sites showed stronger interest in income generation than more subsistence-oriented inland sites. The ex ante impact assessments highlight positive and negative expectations for most interventions, with increased labor burden being the most prominent negative impact overall. Conclusions: The findings suggest that participatory, multidimensional impact assessments before project implementation can support development stakeholders in tailoring intervention packages, considering 1) local and gendered preferences and 2) trade-offs among development objectives.

Endemic malagasy Dalbergia species inhibit quorum sensing in Pseudomonas aeruginosa PAO1.

Various species of the plant genus Dalbergia are traditionally used as medicine for sundry ailments and some of them have been shown recently to quench the virulence of Gram-positive and Gram-negative bacteria. Cell-to-cell communication mechanisms, quorum sensing (QS) in particular, are key regulators of virulence in many pathogenic bacteria. Screening n-hexane extracts of leaves, roots and bark of endemic Malagasy Dalbergia species for their capacity to antagonize QS mechanisms in Pseudomonas aeruginosa PAO1 showed that many reduced the expression of the QS-regulated genes lasB and rhlA. However, only the extract of Dalbergia trichocarpa bark (DTB) showed a significant reduction of QS gene expression without any effect on the aceA gene encoding a QS-independent isocitrate lyase. Further characterization of DTB impact on QS revealed that the QS systems las and rhl are inhibited and that swarming, twitching, biofilm formation and the production of pyocyanin, elastase and proteases are also hampered in the presence of the DTB extract. Importantly, compared with the known QS inhibitor naringenin, the DTB extract showed a stronger negative effect on twitching, biofilm formation and tobramycin resistance. Preliminary structural characterization of these potent biofilm disrupters suggests that they belong to the phytosterols. The strong inhibition of motility and biofilm formation suggests that the DTB extract contains agents disrupting biofilm architecture, which is an important observation in the context of the design of new drugs targeting biofilm-encapsulated pathogens.

Study in vitro of the impact of endophytic bacteria isolated from Centella asiatica on the disease incidence caused by the hemibiotrophic fungus Colletotrichum higginsianum.

Thirty-one endophytic bacteria isolated from healthy leaves of Centella asiatica were screened in vitro for their ability to reduce the growth rate and disease incidence of Colletotrichum higginsianum, a causal agent of anthracnose. Isolates of Cohnella sp., Paenibacillus sp. and Pantoea sp. significantly stimulated the growth rate of C. higginsianum MUCL 44942, while isolates of Achromobacter sp., Acinetobacter sp., Microbacterium sp., Klebsiella sp. and Pseudomonas putida had no influence on this plant pathogen. By contrast, Bacillus subtilis BCA31 and Pseudomonas fluorescens BCA08 caused a marked inhibition of C. higginsianum MUCL 44942 growth by 46 and 82 %, respectively. Cell-free culture filtrates of B. subtilis BCA31 and P. fluorescens BCA08 were found to contain antifungal compounds against C. higginsianum MUCL 44942. Inoculation assays on in vitro-cultured plants of C. asiatica showed that foliar application of B. subtilis BCA31, three days before inoculation with C. higginsianum MUCL 44942, significantly reduced incidence and severity of the disease. The role of endophytic bacteria in maintaining the apparent inactivity of C. higginsianum MUCL 44942 in C. asiatica grown in the wild is discussed.

Comparative analysis of active constituents in Centella asiatica samples from Madagascar: application for ex situ conservation and clonal propagation.

A comparative quantitative analysis of the active triterpenoids in Centella asiatica samples collected in different locations in Madagascar was carried out to evaluate the natural variability in triterpenoid content and to select elite samples for further ex situ germplasm conservation and clonal propagation. The highest asiaticoside content (6.42%) was measured in samples collected in Mangoro region. In vitro propagation of C. asiatica was successfully achieved in hormone-free medium. Although lower asiaticoside content was detected in 8-week-old vitro plants, the Mangoro sample still showed the highest content in this triterpenoid constituent (1.78%). Acetoxycentellynol, a C(15)-polyacetylene, was found to be accumulated up to 18 times more in in vitro plants as compared to plant material collected in situ.