30 research outputs found

    Ecological Aspects of a Wood Turtle, Glyptemys insculpta, Population at the Northern Limit of its Range in Québec

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    As part of a conservation research initiative, a population of Wood Turtles (Glyptemys insculpta) at the northern limit of its range was studied to ascertain characteristics of its demographics, morphometrics, density, mortality, feeding, and mating activities. Turtles were captured and marked during the activity period in 1996 and 1997. In addition, 20 individuals were radio-tracked weekly. A total of 188 turtles was captured and the size of the population in the study area was estimated at 238 turtles. The estimated population density based on this calculation is 0.44 turtles/ha. This is less than other studies indicating that population densities are greater in southern populations. Turtles from this population were large (carapace length of males=214.5 ± 4.21 mm, females=201.1 ± 10.88 mm) which supports the hypothesis that turtle size is negatively correlated with number of frost free days. The sex ratio was not significantly different from 1:1. Juvenile turtles accounted for 31.4% of the population. Observations of feeding habits support the claim that Wood Turtles are opportunistic omnivores. Of the 35 mating or courtship events observed, 77 % occurred in the fall and half of them between 11:00 and 13:00. Although limb and tail injuries and parasites were observed on many turtles, no dead turtles were observed. This last result, combined with the high rate of recruitment and even sex ratio suggests that this population is stable, making it an ideal population with which to make comparisons with other studies in areas where the species could be in decline

    Identification and functional characterization of small non-coding RNAs in Xanthomonas oryzae pathovar oryzae

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    <p>Abstract</p> <p>Background</p> <p>Small non-coding RNAs (sRNAs) are regarded as important regulators in prokaryotes and play essential roles in diverse cellular processes. <it>Xanthomonas oryzae </it>pathovar <it>oryzae </it>(<it>Xoo</it>) is an important plant pathogenic bacterium which causes serious bacterial blight of rice. However, little is known about the number, genomic distribution and biological functions of sRNAs in <it>Xoo</it>.</p> <p>Results</p> <p>Here, we performed a systematic screen to identify sRNAs in the <it>Xoo </it>strain PXO99. A total of 850 putative non-coding RNA sequences originated from intergenic and gene antisense regions were identified by cloning, of which 63 were also identified as sRNA candidates by computational prediction, thus were considered as <it>Xoo </it>sRNA candidates. Northern blot hybridization confirmed the size and expression of 6 sRNA candidates and other 2 cloned small RNA sequences, which were then added to the sRNA candidate list. We further examined the expression profiles of the eight sRNAs in an <it>hfq </it>deletion mutant and found that two of them showed drastically decreased expression levels, and another exhibited an Hfq-dependent transcript processing pattern. Deletion mutants were obtained for seven of the Northern confirmed sRNAs, but none of them exhibited obvious phenotypes. Comparison of the proteomic differences between three of the ΔsRNA mutants and the wild-type strain by two-dimensional gel electrophoresis (2-DE) analysis showed that these sRNAs are involved in multiple physiological and biochemical processes.</p> <p>Conclusions</p> <p>We experimentally verified eight sRNAs in a genome-wide screen and uncovered three Hfq-dependent sRNAs in <it>Xoo</it>. Proteomics analysis revealed <it>Xoo </it>sRNAs may take part in various metabolic processes. Taken together, this work represents the first comprehensive screen and functional analysis of sRNAs in rice pathogenic bacteria and facilitates future studies on sRNA-mediated regulatory networks in this important phytopathogen.</p

    Carbone des sols en Afrique

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    Les sols sont une ressource essentielle à préserver pour la production d’aliments, de fibres, de biomasse, pour la filtration de l’eau, la préservation de la biodiversité et le stockage du carbone. En tant que réservoirs de carbone, les sols sont par ailleurs appelés à jouer un rôle primordial dans la lutte contre l’augmentation de la concentration de gaz à effet de serre. Ils sont ainsi au centre des objectifs de développement durable (ODD) des Nations unies, notamment les ODD 2 « Faim zéro », 13 « Lutte contre le changement climatique », 15 « Vie terrestre », 12 « Consommation et production responsables » ou encore 1 « Pas de pauvreté ». Cet ouvrage présente un état des lieux des sols africains dans toute leur diversité, mais au-delà, il documente les capacités de stockage de carbone selon les types de sols et leurs usages en Afrique. Il propose également des recommandations autour de l’acquisition et de l’interprétation des données, ainsi que des options pour préserver, voire augmenter les stocks de carbone dans les sols. Tous les chercheurs et acteurs du développement impliqués dans les recherches sur le rôle du carbone des sols sont concernés par cette synthèse collective. Fruit d’une collaboration entre chercheurs africains et européens, ce livre insiste sur la nécessité de prendre en compte la grande variété des contextes agricoles et forestiers africains pour améliorer nos connaissances sur les capacités de stockage de carbone des sols et lutter contre le changement climatique

    The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

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    INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

    A partnership between science and industry for a monitoring of anchovy & sardine in the Bay of Biscay: When fishermen are actors of science

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    Anchovy and sardine are small pelagic species occupying similar geographic areas in the Bay of Biscay (North-East Atlantic). Their biomass is strongly dependent on recruitment, making the annual assessment of TAC (Total Allowable Catch) a risky strategy due to uncertainty in predicting the magnitude of recruitment. Monitoring these resources more often and throughout their life cycle could allow management strategies to be adjusted based on observations which indicate the level of recruitment. In order to achieve a more frequent monitoring, an innovative data collection strategy involving a partnership between fishermen and scientists, was developed in 2009 and 2010 called “pilot sentinel surveys”. This paper details the partnership, the information such a partnership can provide and how it can be useful for adaptively managing such resources. The method was based on short surveys undertaken by commercial vessels several times per year, in two spatially limited “key areas” known to be potential recruitment habitats. Acoustic surveys and fishing operations enabling biological sampling, were combined in each key area. Only one scientist was on board and an ad hoc sampling strategy was adopted during each survey by the Captain–Scientist team depending on the local conditions. This partnership allowed scientists to benefit from fishermen’s experience and therefore adopt a sampling strategy which was optimized in time and space. The sentinel survey data were complemented with data collected during annual spring acoustic surveys carried out by the research vessel (RV) Thalassa. The RV was accompanied by commercial vessels allowing additional fishing operations and acoustic echo interpretation to be performed. This experiment showed that the sentinel observations in limited areas cannot provide reliable abundance indices, but are adequate to provide significant biological information on the seasonal progress of the life cycle of each species, such as growth, timing of in-coming recruitment and migration pattern. In addition, these “pilot sentinel surveys” significantly improved the mutual understanding between fishermen and scientists

    Les marais à poissons du littoral atlantique

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    AutresCe fascicule est destiné à faire connaître l'évolution récente, les enjeux et la gestion des marais à poissons et à mettre en avant le rôle prépondérant des particuliers, des propriétaires et des usagers de ces espaces dans la qualité de ces territoires
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