Antimicrobial activity of polyphenol-rich fractions from Sida alba L. (Malvaceae) against co-trimoxazol-resistant bacteria strains

<p>Abstract</p> <p>Background</p> <p>The increased resistance of microorganisms to the currently used antimicrobials has lead to the evaluation of other agents that might have antimicrobial activity. Medicinal plants are sources of phytochemicals which are able to initiate different biological activities including antimicrobials</p> <p>Materials and methods</p> <p><it>In vitro </it>antibacterial (MIC, MBC and time-kill studies) of polyphenol-rich fractions from <it>Sida alba </it>L. (Malvaceae) was assessed using ten bacteria strains (Gram-negative and Gram-positive).</p> <p>Results</p> <p>All test bacteria were susceptible to the polyphenol-rich fractions. Time-kill results showed that after 5 h exposition there was no viable microorganism in the initial inoculum and the effect of polyphenol-rich fractions was faster on <it>Enterococcus faecalis </it>(Gram-positive bacterium) comparatively to the other bacteria strains.</p> <p>Conclusion</p> <p>The data analysis indicates that the tested of polyphenol-rich fractions has significant effects when compared with the standard antibiotic. These results therefore justify the traditional use of <it>sida alba </it>L., alone or in combination with other herbs to treat bacterial infections.</p

Decline in the seroprevalence of syphilis markers among first-time blood donors in Libreville (Gabon) between 2004 and 2016.

BACKGROUND: Very few studies have been conducted on the seroprevalence of syphilis in Gabon. According to the World Health Organization, the average seroprevalence of syphilis has declined from 5.5 to 1.1% in Central Africa. The aim of this study was to test the hypothesis that syphilis decreased in Gabon between 2004 and 2016 and to identify factors involved in this pattern by testing a large sample of first-time blood donors in the capital Libreville. METHODS: The detection of Treponema pallidum was done using a Rapid Plasma Reagin test (RPR) and confirmed by an ELISA test using the Biorad Syphilis Total Antibody EIA II kit or BioMerieux Trepanostika TP recombinant. Assays were performed by dedicated technicians according to manufacturers' recommendations and following the laboratory standard operating procedures. Test results were manually transferred into the laboratory Excel files and hand-written in the laboratory logbook for syphilis testing. Logistic regression was used to assess the impact of sociodemographic characteristics on syphilis marker seroprevalence in both univariate and multivariable analysis. Odds ratios (OR) and 95% confidence intervals were calculated. RESULTS: The seroprevalence of syphilis markers was 8.4% (95% CI = 7.9-8.9) in 2004 and 2.4% (95% CI = 2.1-2.7) in 2016. The difference was significant [OR = 3.78; 95% CI (3.26-4.38); P < 0.001]. The decrease in syphilis seroprevalence was significant in both women and men and in each age group in univariate analysis. In multivariable analysis, controlling for all sociodemographic factors, the decrease in syphilis seroprevalence from 2004 to 2016 remained significant (OR = 3.29; 95% CI = 2.88-3.88, P < 0.001). The seroprevalence of syphilis decreased significantly in men compared to women and young donors compared to donors aged ≥36 years. CONCLUSIONS: This study shows a significant decline in syphilis seroprevalence in first-time blood donors in Libreville, Gabon. Government actions, including multiple HIV prevention activities, are a likely part of this decline

L'acide parachloromercuribenzenesulfonique : un marqueur possible d'affinite differentielle du transporteur de saccharose chez la feve (Vicia faba L.)

SIGLECNRS T 56623 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Phenotypic plasticity in size of ant-domatia

International audienceAnt-plants produce hollow structures called domatia to host protecting ants. Although size variation in domatia is well documented between related species, intraspecific variation is little explored. The central African ant-plant Barteria dewevrei exibits strong variation in domatium size, giving the opportunity to explore the mechanism underlying variation in a mutualistic trait. We showed that domatium size in Barteria dewevrei varies between sites. We transplanted individual plants between two sites in Gabon where plants have different domatium sizes. Domatium size of transplanted plants changed, revealing that variation in this mutualistic trait is driven by phenotypic plasticity. The two sites differed in their environmental conditions: highland open savanna on sandy soil vs lowland closed tropical rain forest on sandy-loam soil. However, as stomatal density and δ 13 C of leaves did not differ between sites or between branches produced before and after transplantation, we have no cue on the role of abiotic stress (such as light intensity and water availability) in domatium size variation. As the obligate Tetraponera ant symbionts are too large to fit in the small domatia, variation of the mutualistic trait in response to environmental change through phenotypic plasticity may impact this specialized mutualism