99 research outputs found

    Functional and Taxonomic Diversity of Collembola as Complementary Tools to Assess Land Use Effects on Soils Biodiversity

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    Collembola have been proposed for several decades as a good model organisms to survey soil biodiversity; but most of the studies focused on taxonomic endpoints. The main objectives of this study are to compare the effects of the different land uses, including urban and industrial land uses, while using both collembolan functional and taxonomic biodiversity approaches. We collected data on 3,056 samples of Collembola communities across 758 sites in various land uses throughout France. The types of land use considered included all types of human activity from forestry to urban, industrial, traffic, mining and military areas, agricultural grassland, arable land, vineyards and urban vegetable gardens. In order to study functional and taxonomic biodiversity, we used community-weighted means, functional indices, species richness and density. When looking at collembolan functional diversity, urban and industrial soils appear clearly less diversified than when considering the taxonomic diversity. We suspect here a functional homogenization effect commonly reported in the literature for various organisms in urban ecosystems. Our study provides range of values for different taxonomic and functional indices of Collembola communities in a wide land use classification across France

    Shedding Light on Vampires: The Phylogeny of Vampyrellid Amoebae Revisited

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    With the advent of molecular phylogenetic techniques the polyphyly of naked filose amoebae has been proven. They are interspersed in several supergroups of eukaryotes and most of them already found their place within the tree of life. Although the ‘vampire amoebae’ have attracted interest since the middle of the 19th century, the phylogenetic position and even the monophyly of this traditional group are still uncertain. In this study clonal co-cultures of eight algivorous vampyrellid amoebae and the respective food algae were established. Culture material was characterized morphologically and a molecular phylogeny was inferred using SSU rDNA sequence comparisons. We found that the limnetic, algivorous vampyrellid amoebae investigated in this study belong to a major clade within the Endomyxa Cavalier-Smith, 2002 (Cercozoa), grouping together with a few soil-dwelling taxa. They split into two robust clades, one containing species of the genus Vampyrella Cienkowski, 1865, the other containing the genus Leptophrys Hertwig & Lesser, 1874, together with terrestrial members. Supported by morphological data these clades are designated as the two families Vampyrellidae Zopf, 1885, and Leptophryidae fam. nov. Furthermore the order Vampyrellida West, 1901 was revised and now corresponds to the major vampyrellid clade within the Endomyxa, comprising the Vampyrellidae and Leptophryidae as well as several environmental sequences. In the light of the presented phylogenetic analyses morphological and ecological aspects, the feeding strategy and nutritional specialization within the vampyrellid amoebae are discussed

    The anterolateral ligament of the knee: unwrapping the enigma. Anatomical study and comparison to previous reports.

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    It has been suggested that the anterolateral ligament (ALL) of the knee may have importance in limiting rotational instability, and reconstruction may prevent a continued pivot-shift following anterior cruciate ligament surgery. However, the anatomy of this ligament has not been consistently reported in recent publications. We describe our experience of cadaveric dissection with reference to other published work.This article is freely available via Open Access. Click on the 'Additional Link' above to access the full-text from the publisher's site.Published (Open Access

    The anterolateral complex of the knee: results from the International ALC Consensus Group Meeting

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    The structure and function of the anterolateral complex (ALC) of the knee has created much controversy since the 're-discovery' of the anterolateral ligament (ALL) and its proposed role in aiding control of anterolateral rotatory laxity in the anterior cruciate ligament (ACL) injured knee. A group of surgeons and researchers prominent in the field gathered to produce consensus as to the anatomy and biomechanical properties of the ALC. The evidence for and against utilisation of ALC reconstruction was also discussed, generating a number of consensus statements by following a modified Delphi process. Key points include that the ALC consists of the superficial and deep aspects of the iliotibial tract with its Kaplan fibre attachments on the distal femur, along with the ALL, a capsular structure within the anterolateral capsule. A number of structures attach to the area of the Segond fracture including the capsule-osseous layer of the iliotibial band, the ALL and the anterior arm of the short head of biceps, and hence it is not clear which is responsible for this lesion. The ALC functions to provide anterolateral rotatory stability as a secondary stabiliser to the ACL. Whilst biomechanical studies have shown that these structures play an important role in controlling stability at the time of ACL reconstruction, the optimal surgical procedure has not yet been defined clinically. Concern remains that these procedures may cause constraint of motion, yet no clinical studies have demonstrated an increased risk of osteoarthritis development. Furthermore, clinical evidence is currently lacking to support clear indications for lateral extra-articular procedures as an augmentation to ACL reconstruction. The resulting statements and scientific rationale aim to inform readers on the most current thinking and identify areas of needed basic science and clinical research to help improve patient outcomes following ACL injury and subsequent reconstruction. Level of evidence V

    Étude comparative du pouvoir pathogĂšne expĂ©rimental de souches d’

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    Nous avons recherchĂ© la pathogĂ©nicitĂ© sur la souris aprĂšs instillation nasale de 8 souches d’Acanthamoeba isolĂ©es de piscines. La souche Al d’Acanthamoeba culbertsoni a Ă©tĂ© aussi testĂ©e comme souche pathogĂšne de rĂ©fĂ©rence.La virulence est Ă©valuĂ©e par un essai de dĂ©termination des D.L. 50 pour chaque souche aprĂšs Ă©tude de la variation de la mortalitĂ© observĂ©e (transformation probit) en fonction de la dose instillĂ©e.On constate que la majoritĂ© des souches du genre Acanthamoeba (6 sur 8) isolĂ©es Ă  partir du milieu extĂ©rieur (piscines) sont capables de provoquer la mort d’un certain pourcentage de souris aprĂšs instillation nasale. Mais la pathogĂ©nicitĂ© potentielle ainsi rĂ©vĂ©lĂ©e varie dans de grandes proportions (D.L. 50 comprises entre 4.102 et 4.105) d’une souche d’Acanthamoeba Ă  une autre.Enfin, il ne semble pas exister chez les Acanthamoeba de corrĂ©lation entre le pouvoir pathogĂšne observĂ© et l’appartenance Ă  une espĂšce dĂ©terminĂ©e

    Étude sur la prĂ©sence d’« amibes libres » dans les eaux des piscines lyonnaises

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    PrĂšs de 90 % des 44 prĂ©lĂšvements d’eau effectuĂ©s dans 9 piscines lyonnaises renfermaient des amibes. A partir de ceux-ci, 85 souches ont pu ĂȘtre sĂ©parĂ©es. MalgrĂ© l’extrĂȘme diversitĂ© des espĂšces rencontrĂ©es, les souches appartenant aux genres Acanthamoeba et Hartmannella prĂ©dominent. En revanche le genre Naegleria paraĂźt exceptionnel : il n’a pu ĂȘtre isolĂ© qu’une seule fois directement Ă  partir de l’eau des bassins
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