The Xanthophyll Carotenoid Lutein Reduces the Invasive Potential of Pseudomonas aeruginosa and Increases Its Susceptibility to Tobramycin.

peer reviewedRecently, the xanthophyll carotenoid lutein has been qualified as a potential quorum sensing (QS) and biofilm inhibitor against Pseudomonas aeruginosa. To address the potential of this xanthophyll compound as a relevant antivirulence agent, we investigated in depth its impact on the invasion capabilities and aggressiveness of P. aeruginosa PAO1, which rely on the bacterial ability to build and maintain protective barriers, use different types of motilities and release myriad virulence factors, leading to host cell and tissue damages. Our data, obtained on the PAO1 strain, indicate that all-trans lutein (Lut; 22 µM) disrupts biofilm formation and disorganizes established biofilm structure without affecting bacterial viability, while improving the bactericidal activity of tobramycin against biofilm-encapsulated PAO1 cells. Furthermore, this xanthophyll affects PAO1 twitching and swarming motilities while reducing the production of the extracellular virulence factors pyocyanin, elastase and rhamnolipids as well as the expression of the QS-regulated lasB and rhlA genes without inhibiting the QS-independent aceA gene. Interestingly, the expression of the QS regulators rhlR/I and lasR/I is significantly reduced as well as that of the global virulence factor regulator vfr, which is suggested to be a major target of Lut. Finally, an oxidative metabolite of Lut, 3'-dehydrolutein, induces a similar inhibition phenotype. Taken together, lutein-type compounds represent potential agents to control the invasive ability and antibiotic resistance of P. aeruginosa.3. Good health and well-bein

Qualité sanitaire et nutritionnelle du cresson et autres légumes-feuilles approvisionnant Antananarivo (Madagascar): diagnostics et conditions de leurs améliorations techniques, socio-économiques et institutionnelles, de la consommation à la production

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Fruit and honey litchi production: activity with positive externalities

International audienc

Consumers' Perception of Watercress Quality in Antananarivo: Process of quality "Watercress Chain"

International audienceWell-known for its high content on vitamin A, watercress is part of the greens widely consumed in the capital city of Madagascar and appreciated by the population. We can find two kinds of watercress' cultivation: the first one is grown in clear water in suburban area; the cultivation on terraces allows the water to be renewed regularly. The second one is located in poluted area with wastewater. Although the consumers concern about the production chain, the market remains stable. In fact, Qualisann project (Quality, Health and Nutrition), led by a multidisciplinary team from different universities, worked to ensure the quality of watercress and to evaluate risks for consumers and producers. This reserach suggests "How do consumers perceive the quality of the watercress and how to ensure the quality process by identifying the actors in the filiere and their role". A survey was conducted to understand consumers' perception of watercress quality, and the knowledge of the watercress plantation and the propensity to pay the quality of the watercress. A qualitative survey of 50 people was followed by a quantitative survey of 1,024 households. They provide the different quality criteria, the source of uncertainty of the quality and the actions from the consumers to face risks. Consumers adopt measures to prevent risks by washing and cooking before consumption. The study shows that consumers are responsible of their food safety. Their knowhow would be a significant contribution to deal with food healthiness. To increase 2 the efficiency of risk regulation, public information should be reinforced to limit asymmetric information

Consumers' Perception of Watercress Quality in Antananarivo: Process of quality "Watercress Chain"

International audienceWell-known for its high content on vitamin A, watercress is part of the greens widely consumed in the capital city of Madagascar and appreciated by the population. We can find two kinds of watercress' cultivation: the first one is grown in clear water in suburban area; the cultivation on terraces allows the water to be renewed regularly. The second one is located in poluted area with wastewater. Although the consumers concern about the production chain, the market remains stable. In fact, Qualisann project (Quality, Health and Nutrition), led by a multidisciplinary team from different universities, worked to ensure the quality of watercress and to evaluate risks for consumers and producers. This reserach suggests "How do consumers perceive the quality of the watercress and how to ensure the quality process by identifying the actors in the filiere and their role". A survey was conducted to understand consumers' perception of watercress quality, and the knowledge of the watercress plantation and the propensity to pay the quality of the watercress. A qualitative survey of 50 people was followed by a quantitative survey of 1,024 households. They provide the different quality criteria, the source of uncertainty of the quality and the actions from the consumers to face risks. Consumers adopt measures to prevent risks by washing and cooking before consumption. The study shows that consumers are responsible of their food safety. Their knowhow would be a significant contribution to deal with food healthiness. To increase 2 the efficiency of risk regulation, public information should be reinforced to limit asymmetric information

Yields and Quality of Italian Ryegrass (Lolium multiflorum) and Common Vetch (Vicia sativa) Grown in Monocultures and Mixed Cultures under Irrigated Conditions in the Highlands of Madagascar

A field experiment was conducted under irrigated conditions in the highlands of Madagascar to assess the potential of intercropping Italian ryegrass with common vetch for improving yield and quality of forage. Seed proportions studied were ryegrass-vetch 100:0; 0:100; 50:33; 50:50; 50:66; 75:33 and 75:66. Mixtures were sown in alternate rows and the sowing rates of pure stands of ryegrass and vetch were 20 and 60 kg per hectare, respectively. The results showed that all mixtures achieved yield advantage over pure stands with the highest land equivalent ratio value for dry matter yield obtained from the mixture of 75:66 (1.47) followed by 50:50 (1.35). Slight increase of crude protein content and protein digested in the small intestine when rumen-fermentable nitrogen is limiting (PDIN) content were obtained from mixtures compared with pure stand of ryegrass. Vetch rate in dry matter yield of mixtures increased with the increase of vetch seed proportion and ranged from 31 to 44%. Agressivity and competitive ratio indices showed that ryegrass was slightly competitive than vetch. Intercropping Italian ryegrass with common vetch at the seed proportions of 75:66 or 50:50 could be a more sustainable alternative cropping to alleviate dry season feed shortages of dairy livestock in the highlands of Madagascar

Malagasy traditional treatments for food crops: A tool to control potato bacterial diseases?

The control and treatment of food crops bacterial diseases remain problematic due to a scarcity of effective phytotreatments. As traditional agricultural practices may represent an attractive venue to explore new treatments, Malagasy traditional practices were investigated for their effectiveness on potato plants. A survey was conducted among Malagasy farmers to collect information on diseases observed on potato crops and on traditional disease control practices. Twelve treatments against potato bacterial diseases were tested on two potato varieties, in experimental plots naturally infected by bacterial wilt disease. The information collected from 52 farmers (i) showed that leaf spots and bacterial wilt disease are the most frequently identified threats for potato crops; and (ii) allowed to identify 12 traditional treatments among which five exhibited protective properties on potato bacterial wilt disease. Moreover, one recipe (R07) was effective on the two potato varieties after two applications per week for 10 weeks, with 50% and 72% effectiveness rate, respectively. Valorization of traditional practices may provide an effective, safe, economic and standardized phytotreatment against potato bacterial wilt disease.SCOPUS: ar.jinfo:eu-repo/semantics/inPres