Search results for "Population biology"
showing 10 items of 252 documents
Mortality and demographic recovery in early post-black death epidemics: Role of recent emigrants in medieval Dijon
2020
International audience; Objective and methodsWe analyze the influence of population movement on susceptibility to death and resilience during two epidemics occurring in Dijon soon after the Black Death. Using a specific program designed to propose links between entries in annual tax registers, we define tentative heads of household, the elapsed time since their first registration and their ties with other persons within the city.ResultsDuring the 1400 epidemic heads of household who were registered for 1–3 years die in large numbers, whereas during years without epidemics, their death rate is lower than that of heads of household who were registered longer. Recent registration is an epidemi…
Reference set of Mycobacterium tuberculosis clinical strains: A tool for research and product development
2018
TheMycobacterium tuberculosiscomplex (MTBC) causes tuberculosis (TB) in humans and various other mammals. The human-adapted members of the MTBC comprise seven phylogenetic lineages that differ in their geographical distribution. There is growing evidence that this phylogenetic diversity modulates the outcome of TB infection and disease. For decades, TB research and development has focused on the two canonical MTBC reference strains H37Rv and Erdman, both of which belong to Lineage 4. Relying on only a few laboratory-adapted strains can be misleading as study results might not be directly transferrable to clinical settings where patients are infected with a diverse array of strains, includin…
Mitochondrial DNA Regionalism and Historical Demography in the Extant Populations of Chirocephalus kerkyrensis (Branchiopoda: Anostraca)
2012
BackgroundMediterranean temporary water bodies are important reservoirs of biodiversity and host a unique assemblage of diapausing aquatic invertebrates. These environments are currently vanishing because of increasing human pressure. Chirocephalus kerkyrensis is a fairy shrimp typical of temporary water bodies in Mediterranean plain forests and has undergone a substantial decline in number of populations in recent years due to habitat loss. We assessed patterns of genetic connectivity and phylogeographic history in the seven extant populations of the species from Albania, Corfu Is. (Greece), Southern and Central Italy.Methodology/principal findingsWe analyzed sequence variation at two mito…
MICROBIAL COMMUNITY CHANGES IN TNT SPIKED SOIL BIOREMEDIATION TRIAL USING BIOSTIMULATION, PHYTOREMEDIATION AND BIOAUGMENTATION
2013
Trinitrotoluene (TNT), a commonly used explosive for military and industrial applications, can cause serious environmental pollution. 28-day laboratory pot experiment was carried out applying bioaugmentation using laboratory selected bacterial strains as inoculum, biostimulation with molasses and cabbage leaf extract, and phytoremediation using rye and blue fenugreek to study the effect of these treatments on TNT removal and changes in soil microbial community responsible for contaminant degradation. Chemical analyses revealed significant decreases in TNT concentrations, including reduction of some of the TNT to its amino derivates during the 28-day tests. The combination of bioaugmentation…
Evidence for shifts in the structure and abundance of the microbial community in a long-term PCB-contaminated soil under bioremediation.
2011
International audience; Although the impact of bioremediation of PCB-contaminated sites on the indigenous microbial community is a key question for soil restoration, it remains poorly understood. Therefore, a small-scale bioremediation assay made of (a) a biostimulation treatment with carvone, soya lecithin and xylose and (b) two bioaugmentation treatments, one with a TSZ7 mixed culture and another with a Rhodococcus sp. Z6 pure strain was set up. Changes in the structure of the global soil microbial community and in the abundances of different taxonomic phyla were monitored using ribosomal intergenic spacer analysis (RISA) and real-time PCR. After an 18-month treatment, the structure of th…
Mapping and determinism of soil microbial community distribution across an agricultural landscape.
2015
Article en open access; International audience; Despite the relevance of landscape, regarding the spatial patterning of microbial communities and the relative influence of environmental parameters versus human activities, few investigations have been conducted at this scale. Here, we used a systematic grid to characterize the distribution of soil microbial communities at 278 sites across a monitored agricultural landscape of 13km(2). Molecular microbial biomass was estimated by soil DNA recovery and bacterial diversity by 16S rRNA gene pyrosequencing. Geostatistics provided the first maps of microbial community at this scale and revealed a heterogeneous but spatially structured distribution…
Relationships between soil water repellency and microbial community composition under different plant species in a Mediterranean semiarid forest
2014
Abstract Soil water repellency (SWR) can influence many hydrological soil properties, including water infiltration, uneven moisture distribution or water retention. In the current study we investigated how variable SWR persistence in the field is related to the soil microbial community under different plant species (P. halepensis, Q. rotundifolia, C. albidus and R. officinalis) in a Mediterranean forest. The soil microbial community was determined through phospholipid fatty acids (PLFA). The relationships between microbiological community structure and the soil properties pH, Glomalin Related Soil Protein (GRSP) and soil organic matter (SOM) content were also studied. Different statistical …
Population- and ecosystem-level effects of predation on microbial-feeding nematodes.
2017
We studied the role of nematode predation in the functioning of detrital food webs assembled in microcosms. The microcosms contained defaunated humus and litter materials, a diverse microbial community with bacteria, fungi and protozoa, and a birch (Betula pendula) seedling infected with mycorrhizal fungi. Different levels of top-down control upon microbivorous nematodes were set up by assembling food webs either without predators, or in combinations with a specialist and a non-specialist predatory mite (Mesostigmata). The nematode community was composed of either (1) three species of bacterivorous, or (2) three species of fungivorous nematodes or (3) both groups together. After two growing…
Long-term impact of 19 years' farmyard manure or sewage sludge application on the structure, diversity and density of the protocatechuate-degrading b…
2012
International audience; Impact of long-term biosolids application on soil-living micro-organisms key players of ecosystemic services is scarcely reported. Here, the impact of the 19 year-long application of farmyard manure (FM) and sewage sludge (SS) organic fertilisation regimes on the protocatechuate-degrading bacterial (pca) community was estimated by comparison to a mineral fertilisation regime (U). The structure, diversity and density of the pca community were determined using pcaH, a gene encoding the protocatechuate 3,4-dioxygenase. Ten years after the last application, the structure of the pca community in soils amended with 55100 (100 t/ha/2 years) and to a lesser extent with FM (1…
Aplicação do conceito One Health na área hiperendêmica de fasciolíase humana do Altiplano Boliviano: biologia dos limneídeos, dinâmica populacional, …
2021
Abstract Fascioliasis is a freshwater snail-borne zoonotic disease. The Northern Bolivian Altiplano is a very high altitude endemic area where the highest human prevalences and intensities have been reported. Preventive chemotherapy by treatment campaigns is yearly applied. However, liver fluke infection of cattle, sheep, pigs and donkeys assures endemicity and consequent human infection and re-infection risks. A One Health action has therefore been implemented. Activity concerns lymnaeid vectors and environment diversity. Studies included growth, egg-laying and life span in laboratory-reared lymnaeids. Different habitat types and influencing factors were assessed. All populations proved to…