Richardia brasiliensis Collected in Southern-Benin: Phytochemical Screening, Antimicrobial Activity and Toxicity

Aims: The aim of this study is to evaluate the antimicrobial activity of the R. brasiliensis aerial part extracts collected in southern-Benin. Methodology: The phytochemical screening was performed by a differential precipitation staining method. Aqueous and ethanolic extracts were made using conventional method with water and ethanol as solvent. The obtained extracts were used to evaluate their antimicrobial activity on Staphylococcus aureus strains isolated from skin infections and ten reference strains by the solid-medium diffusion method. The minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) were determined by the liquid macro-dilution method. The cytotoxic effect of the extracts was evaluated on Artemia salina larvae obtained by hatching. Results: The phytochemical screening showed a strong presence of tannins, flavonoids, terpenes, steroids and a medium presence of alkaloids, anthocyanins and mucilage’s. The extraction yields vary according to the solvent: water (15.5%) and ethanol (10.30%). The two extracts variously (p<0.001) inhibited the growth of Staphylococcus aureus strains isolated from skin infections and four reference strains (Staphylococcus aureus ATCC29213, Pseudomonas aeruginosa ATCC27853, Proteus mirabilis A24974, Escherichia coli ATCC25922). However, there is no difference (p > 0.05) in inhibition of strains growth between 24h and 48h. The largest diameter (21±0.75 mm) of inhibition with the reference strains was obtained with P. aeruginosa by action of the aqueous extract. Regarding Staphylococcus aureus strains isolated from skin infections, the largest diameter of inhibition is about 19.25±2.75 mm obtained with strains isolated from ulcers. The average mics of 2.81 mg/ml and 2.08 mg/ml were obtained respectively for the aqueous and ethanolic extracts in the presence of the reference strains. The LC50 determination obtained using the regression line is 0.36 mg/ml for the aqueous extract and 1.16 mg/ml for the ethanolic extract. Conclusion: The aqueous extract is more effective because of its action spectrum. This extract can be used for the development of a soap or ointment to fight against skin infections.

LCA and nutritional assessment of southern Benin market vegetable gardening across the production continuum

Purpose The goal of this work is to analyse the environmental impacts across the productive continuum of market gardening in southern Benin, to determine whether significant differences exist amongst the types of production, and to highlight their hotpots suitable to improvement. Moreover, the relative nutritional quality of products from different production system types were compared to determine whether there were differences and to assess them in relation to the associated environmental impacts. Methods LCA and laboratory analyses were performed on a representative sample of systems and products (carrot, cucumber, tomato, lettuce, watermelon). The resulting scores (single scores for LCA and Nutrient Rich Food scores for nutritional quality) were statistically treated to identify the representativeness of their differences across production sites and production types (featuring distinctive production strategies: Conventional — synthetic fertilisers and pesticides, Organic — organic fertilisers and pesticides and “Lean” — limited inputs). Results and discussion Statistically significant differences across environmental scores were found amongst production sites (for carrot, lettuce and all crops) and types (for carrot and all crops). For tomato, produced on all sites, under all production types, the natural and management-driven variability is large enough that no significant differences were found. Impacts are dominated by direct emissions from (over-)fertilisation and by fuel consumption for water pumping. Despite the absence of significant differences amongst production system types regarding the contents of both β-carotene and polyphenols, the nutritional indices suggest at least marginal differences across types regarding the overall nutritional value of carrot and tomato across types. Based on the limited data available, it cannot be stated that such differences are statistically significant. For carrot, there seems to be a correlation between nutritional quality and environmental impacts, with higher nutritional scores associated with lower environmental impacts. For tomato, it does not seem to exist a correlation. Conclusions Significant differences in environmental scores exist amongst the types of production, with the larger impact associated with organic production, whilst that no statistically significant differences on nutritional quality can be demonstrated across types. Overall improvement of these systems would be achieved by less energy-intensive irrigation, organic waste processing platforms to reduce volatilisation losses, knowledge on the fertilising value of organic waste, and agricultural extension services or technical guides on good agricultural practices to reduce over-fertilisation and other negative environmental impacts.

Dynamics of organophosphate and carbamate resistance in Anopheles gambiae s. l. populations from south and north Benin, West Africa

The current study was aimed to investigate on dynamics of propoxur resistance in Anopheles gambiae s.l. populations from N’ dali district in northern Benin (West Africa) and also to investigate on dynamics of malathion resistance in Anopheles gambiae s. l. populations from Toffo district in southern Benin. Larvae and pupae of Anopheles gambiae s. l . mosquitoes were collected from the breeding sites in Borgou and Atlantic departments in 2015 and 2019. WHO susceptibility tests were conducted on unfed female mosquitoes aged 2-5 days old. WHO bioassays were performed with impregnated papers with propoxur 0.1% and with malathion 5%. PCR techniques were used to detect species and Ace-1 mutations in 2015. Anopheles gambiae s. l. populations from N’dali were resistant to propoxur in 2015 and were still remained resistant to this product in 2019. Regarding Anopheles gambiae s. l. populations from Toffo, they were susceptible to malathion in 2015 whereas the malathion resistance status of these mosquitoes requires further investigation in 2019. PCR revealed that all specimens tested were Anopheles gambiae s. s. The presence of Ace-1R at very low frequency (0.01) was observed in Anopheles gambiae s. l. populations from both districts. This study shows that propoxur resistance detected in An. gambiae s. l. populations from N’ dali needs to be monitored for insecticide resistance in this area.

Evaluation of the Microbiological Quality of Soy Cheeses Sold at the Dantokpa Market in the Municipality of Cotonou in Benin

The objective of this study is to contribute to improving the health quality of soy cheese produced and sold in Benin, through the evaluation of the microbiological quality of samples taken at the Dantokpa market in southern Benin. Samples were taken from the women producers and sellers of this cheese in this market. A total of two hundred and forty (240) samples were collected from five producer-sellers. The cheese samples were sent under suitable conditions to the laboratory where various microbiological analyzes were performed. The results revealed that salmonella, sulfite-reducing anaerobic bacteria (SRA), Escherichia coli and Staphylococcus aureus were absent in all samples. In contrast, aerobic mesophilic bacteria and total coliforms were present at loads above the limit values ​​established for food intended for human consumption. The microbiological quality of the products analyzed was generally unsatisfactory. Consequently, it is necessary to put in place a policy to raise awareness among producers-sellers of the markets on hygiene rules in order to guarantee the safety of consumers.

Evaluation of the Distribution of Shrimp Species Found in Southern Benin Through the Lake Nokoué-ocean Complex

BackgroundThe export of shrimp to the European Union was one of the mainstays of the Beninese economy. It is an income-generating activity for the populations living along lake Nokoué. The lack of a fisheries management strategy has caused a drastic decline in shrimp production in lake Nokoué since 2003. To remedy this problem, it is necessary to hypothesize on their spatio-temporal dynamics in the lake Nokoué-Cotonou channel complex. This is investigated by combining a literature review on their life cycles and habitat suitability with spatio-temporal evolution of salinity obtained from in-situ observations.ResultsThe literature review recognizes the presence in southern Benin of species of the genus Macrobrachium, Atya and Desmocaris (seven, two and one respectively) and five species of marine shrimps belonging to three genera: the genus Penaeus, the genus Holthuispenaeopsis and the genus Parapenaeus. From information on the ecology and physical environment it is shown that adults of the species of the genus Macrobrachium and genus Atya have a favorable environment in lake Nokoué from August to November, their larvae must remain in the lake from December to June to ensure their survival. The species of the genus Desmocaris, which carry out their entire life cycle in fresh water, can stay in lake Nokoué from August to November. The species of the genus Penaeus can find a favorable environment in lake Nokoué from December to June but their larvae can only survive in the sea. Finally, the species of the genus Holthuispenaeopsis and Parapenaeus spend their entire life cycle at sea.ConclusionsThis work allows understanding contrasted life cycles of shrimp’s genera Macrobrachium and Atya compared to Penaeus in a complex ecosystem characterized by strong saline variation. This research allows to predict the presence or absence of shrimp’s genera Macrobrachium, Atya, Desmocaris and Penaeus in a lake system, on the basis of salinity distribution, for a sustainable management of their exploitation.

Serological, molecular and phylogenetic analysis of Rice Yellow Mottle Virus (RYMV) isolates collected in Southern-Benin

The rice yellow mottle is the best known viral disease of rice in Africa. It causes significant economic losses in farmer’s fields. The serological properties of Rice Yellow Mottle Virus (RYMV) isolates, collected in Southern Benin, were assessed by immunological tests with polyclonal and monoclonal antibodies (Pabs and MAbs). The isolates CP (Capsid protein) portions, obtained by RT-PCR, were sequenced and their amino-acids sequences were analyzed and used for phylogenetic analysis. Three different RYMV pathogenic groups, including three resistance breaking (RB) isolates (Be20, Be21 and Be27) which over came allele rymv1-5gene, were identified. Two serotypes Ser1/strain S1 and Ser2/ strain S2 were also distinguished. The molecular properties of the isolates CP gene and the phylogenetic characteristics indicated that the Southern Benin RYMV strain is heterogeneous. The strain S1-Benin linked to the West Central African lineage(S1-WCA) is related to strain from Togo and Niger, whereas, the strain S2 Benin is the stumps of the West African lineage (S1-WA) and is related to Mali, Burkina Faso and Ivory Coast RYMV strains. These results reported the virus pathogenicity level and showed the relationships between RYMV strains in all Dahomey gap countries and in West and Central Africa. Keywords: serotypes, RYMV strains, RB isolates and phylogenetic analysis

Dynamics of organophosphate and carbamate resistance in Anopheles gambiae s. l. populations from south and north Benin, West Africa

The current study was aimed to investigate on dynamics of propoxur resistance in Anopheles gambiae s.l. populations from N’ dali district in northern Benin (West Africa) and also to investigate on dynamics of malathion resistance in Anopheles gambiae s. l. populations from Toffo district in southern Benin. Larvae and pupae of Anopheles gambiae s. l . mosquitoes were collected from the breeding sites in Borgou and Atlantic departments in 2015 and 2019. WHO susceptibility tests were conducted on unfed female mosquitoes aged 2-5 days old. WHO bioassays were performed with impregnated papers with propoxur 0.1% and with malathion 5%. PCR techniques were used to detect species and Ace-1 mutations in 2015. Anopheles gambiae s. l. populations from N’dali were resistant to propoxur in 2015 and were still remained resistant to this product in 2019. Regarding Anopheles gambiae s. l. populations from Toffo, they were susceptible to malathion in 2015 whereas the malathion resistance status of these mosquitoes requires further investigation in 2019. PCR revealed that all specimens tested were Anopheles gambiae s. s. The presence of Ace-1R at very low frequency (0.01) was observed in Anopheles gambiae s. l. populations from both districts. This study shows that propoxur resistance detected in An. gambiae s. l. populations from N’ dali needs to be monitored for insecticide resistance in this area.

Optimization of Biogas Production by Co-Digestion of Organic Waste (Cow Dung and Water Hyacinth)

The objective of this work is to determine the co-digestion ratio of water hyacinth and cow dung for the optimization of biogas production at Sô Ava, a lake city of Southern Benin. To achieve these ratios, we suppose that the water hyacinth has a high gas yield and cow dung ensures stability in the biodigester because it brings fresh bacteria and has a strong buffering capacity (maintenance of a stable pH). For 45 days, we have introduced a mixture of water hyacinth and cow dung in 5 mini-biodigesters of 10 liters each: digester no1 (100% of cow dung); digester no2 (100% of the water hyacinth); digester n° 3 (50% of the water hyacinth and 50% of the cow dung); digester no4 (75% of cow dung and 25% of water hyacinth); digester no5 (75% of the water hyacinth and 25% of the cow dung). The measurements of the pH, temperature and the proportion of gas (CH4, CO2, O2 and H2S) in the mini-biodigesters was done. The measurements show that the digester n° 5 produces the highest capacity of 15.24L of biogas with 70% of methane while the digester n °2 has the lowest capacity 5.47L of biogas with 58% methane. These results show that the yield of biogas produced is greater when using the mixture of the substrate with the ratio of 75% of water hyacinth and 25% of cow dung. This result encourages the energy recovery from water hyacinth, once considered as a seasonal plague which hinders navigation of local boat in the lake.