107 research outputs found

    Hemicryptophytes plant species as indicator of grassland state in semi-arid region: Case study of W Biosphere Reserve and its surroundings area in Benin (West Africa)

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    In semi-arid region managers are facing rapid degradation of grassland. There is a need to determine indicators to be used to detect early change occurring in the grassland for their sustainable management. Thereof, in this study, we explored the reliability of the use of hemicryptophytes as indicator of grassland state in semi-arid region within W Biosphere Reserve and surrounding areas (Benin). Plots of 10 m X 10 m were installed along a land use gradient (from communal lands to the protected area via the buffer zone) in three vegetation types for plant biomass harvesting and hemicryptophytes traits measurement. The hemicryptophyte density, biovolume, tussock size, contact frequency, contribution to total plant biomass and grassland grazing value were assessed and compared between land uses. Findings showed that hemicryptopyte traits were significantly different with the land use type. Hemicryptophyte biovolume and hemicryptophyte contribution were strongly correlated, respectively, with total biomass production and grazing value. The study highlights the relevance of hemicryptophyte as indicators of grassland state that could be used by grassland managers for grassland monitoring, restoration and sustainable use.Keywords: Grassland monitoring, hemicryptophyte traits, indicators, land us

    Assessment of plant communities' pattern and diversity along a land use gradient in W Biosphere Reserve, Benin Republic

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    Human disturbance on vegetation is an important concern in biodiversity conservation. In this study we assessed how anthropogenic disturbance affected plant communities pattern, diversity, life form and chorotype composition along a land use gradient. Vegetation relevés were performed along a land use gradient (park-buffer zone-communal land) at W Biosphere Reserve in Benin. Non-metric multidimensional scaling (NMS) was used to assess plant communities patterns. Indicator species were determined for each plant community and land use. Plant community diversity, life forms and chorotypes composition were assessed and compared among land uses using one-way analysis of variance. NMS ordination showed a good separation between relevés of the park and those from the communal land while relevés of buffer zone were mixed within the park and communal land relevés. There was no significant difference between species richness among land uses types (F = 0.68; p = 0.529, ANOVA test at a level of significance of 5%). The Pielou evenness for the plant communities was higher in the park (E= 0.69±0.04) and buffer zone (E = 0.61±0.13) than in the communal lands (E = 0.44±0.02) while Shannon index showed no clear pattern along land use gradient. Therophytes abundance was significantly higher in the communal land while hemicryptophytes abundance was significantly higher in the park. Wide-distributed species abundance was significantly higher in the communal land whilst Sudanian species showed significantly higher abundance in the park. We concluded that monitoring of the indicator species of the plant communities and their traits are relevant tools for managers to follow-up changes in plant communities

    Comparison of the global prevalence and trend of human intestinal carriage of ESBL-producing Escherichia coli between healthcare and community settings: a systematic review and meta-analysis

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    Objectives:The widespread intestinal carriage of ESBL-producing Escherichia coli (ESBL E. coli) among both patients and healthy individuals is alarming. However, the global prevalence and trend of this MDR bacterium in healthcare settings remains undetermined. To address this knowledge gap, we performed a comparative meta-analysis of the prevalence in community and healthcare settings.Methods:Our systematic review included 133 articles published between 1 January 2000 and 22 April 2021 and indexed in PubMed, EMBASE or Google Scholar. A random-effects meta-analysis was performed to obtain the global pooled prevalence (community and healthcare settings). Subgroup meta-analyses were performed by grouping studies using the WHO regions and 5 year intervals of the study period.Results:We found that 21.1% (95% CI, 19.1%-23.2%) of inpatients in healthcare settings and 17.6% (95% CI, 15.3%-19.8%) of healthy individuals worldwide carried ESBL E. coli in their intestine. The global carriage rate in healthcare settings increased 3-fold from 7% (95% CI, 3.7%-10.3%) in 2001-05 to 25.7% (95% CI, 19.5%-32.0%) in 2016-20, whereas in community settings it increased 10-fold from 2.6% (95% CI, 1.2%-4.0%) to 26.4% (95% CI, 17.0%-35.9%) over the same period.Conclusions:The global and regional human intestinal ESBL E. coli carriage is increasing in both community and healthcare settings. Carriage rates were generally higher in healthcare than in community settings. Key relevant health organizations should perform surveillance and implement preventive measures to address the spread of ESBL E. coli in both settings

    Positively selected modifications in the pore of TbAQP2 allow pentamidine to enter Trypanosoma brucei

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    Mutations in the Trypanosoma brucei aquaporin AQP2 are associated with resistance to pentamidine and melarsoprol. We show that TbAQP2 but not TbAQP3 was positively selected for increased pore size from a common ancestor aquaporin. We demonstrate that TbAQP2’s unique architecture permits pentamidine permeation through its central pore and show how specific mutations in highly conserved motifs affect drug permeation. Introduction of key TbAQP2 amino acids into TbAQP3 renders the latter permeable to pentamidine. Molecular dynamics demonstrates that permeation by dicationic pentamidine is energetically favourable in TbAQP2, driven by the membrane potential, although aquaporins are normally strictly impermeable for ionic species. We also identify the structural determinants that make pentamidine a permeant although most other diamidine drugs are excluded. Our results have wide-ranging implications for optimising antitrypanosomal drugs and averting cross-resistance. Moreover, these new insights in aquaporin permeation may allow the pharmacological exploitation of other members of this ubiquitous gene family
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