409 research outputs found

    Hydrographic conditions and size-fractionated mesoplankton distribution in the Bay of Biscay shelf during spring

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    A general description of the hydrography and the distribution of size-fractionated mesoplankton bio-volume in the Bay of Biscay shelf (from 41° up to 47° 30’ N) during spring (April-May) 2005 is presented. Different hydrographic features, such as the Iberian Poleward Current, continental inputs and associated river plumes, thermohaline fronts or the progression of the seasonal thermocline, were noticeable. Mesoplankton biomass was generally low, except in a narrow coastal fringe along the Spanish shelf and in a relatively extensive area in the inner part of the French shelf, where the seasonal thermocline was already established. The size-structure of the mesoplankton community presented a patchy distribution and significant differences between the surface and sub-surface layers of the water column. The size-fractionated distribution of mesoplankton is discussed in the frame of the observed hydrographic structures.SARDYN EU-project (QLRT-2001-00818

    Abundant mesopelagic fauna at oceanic high latitudes

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    The application of predictive modelling for determining bio-environmental factors affecting the distribution of blackflies (Diptera: Simuliidae) in the Gilgel Gibe watershed in Southwest Ethiopia

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    Blackflies are important macroinvertebrate groups from a public health as well as ecological point of view. Determining the biological and environmental factors favouring or inhibiting the existence of blackflies could facilitate biomonitoring of rivers as well as control of disease vectors. The combined use of different predictive modelling techniques is known to improve identification of presence/absence and abundance of taxa in a given habitat. This approach enables better identification of the suitable habitat conditions or environmental constraints of a given taxon. Simuliidae larvae are important biological indicators as they are abundant in tropical aquatic ecosystems. Some of the blackfly groups are also important disease vectors in poor tropical countries. Our investigations aim to establish a combination of models able to identify the environmental factors and macroinvertebrate organisms that are favourable or inhibiting blackfly larvae existence in aquatic ecosystems. The models developed using macroinvertebrate predictors showed better performance than those based on environmental predictors. The identified environmental and macroinvertebrate parameters can be used to determine the distribution of blackflies, which in turn can help control river blindness in endemic tropical places. Through a combination of modelling techniques, a reliable method has been developed that explains environmental and biological relationships with the target organism, and, thus, can serve as a decision support tool for ecological management strategies

    LifeCLEF: Multimedia Life Species Identification

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    EMR co-located with ACM International Conference on Multimedia Retrieval (ICMR)International audienceBuilding accurate knowledge of the identity, the geographicdistribution and the evolution of living species is essentialfor a sustainable development of humanity as well as forbiodiversity conservation. In this context, using multimediaidentication tools is considered as one of the most promisingsolution to help bridging the taxonomic gap. With therecent advances in digital devices/equipment, network bandwidthand information storage capacities, the production ofmultimedia big data has indeed become an easy task. In parallel,the emergence of citizen sciences and social networkingtools has fostered the creation of large and structured communitiesof nature observers (e.g. eBird, Xeno-canto, TelaBotanica, etc.) that have started to produce outstandingcollections of multimedia records. Unfortunately, the performanceof the state-of-the-art multimedia analysis techniqueson such data is still not well understood and is far fromreaching the real world's requirements in terms of identi-cation tools. The LifeCLEF lab proposes to evaluate thesechallenges around 3 tasks related to multimedia informationretrieval and ne-grained classication problems in 3 livingworlds. Each task is based on large and real-world data andthe measured challenges are dened in collaboration withbiologists and environmental stakeholders in order to reflect realistic usage scenarios

    CCN3: a key growth regulator in Chronic Myeloid Leukaemia

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    Chronic Myeloid Leukaemia (CML) is characterized by expression of the constitutively active Bcr-Abl tyrosine kinase. We have shown previously that the negative growth regulator, CCN3, is down-regulated as a result of Bcr-Abl kinase activity and that CCN3 has a reciprocal relationship of expression with BCR-ABL. We now show that CCN3 confers growth regulation in CML cells by causing growth inhibition and regaining sensitivity to the induction of apoptosis. The mode of CCN3 induced growth regulation was investigated in K562 CML cells using gene transfection and treatment with recombinant CCN3. Both strategies showed CCN3 regulated CML cell growth by reducing colony formation capacity, increasing apoptosis and reducing ERK phosphorylation. K562 cells stably transfected to express CCN3 showed enhanced apoptosis in response to treatment with the tyrosine kinase inhibitor, imatinib. Whilst CCN3 expression was low or undetectable in CML stem cells, primary CD34+ CML progenitors were responsive to treatment with recombinant CCN3. This study shows that CCN3 is an important growth regulator in haematopoiesis, abrogation of CCN3 expression enhances BCR-ABL dependent leukaemogenesis. CCN3 restores growth regulation, regains sensitivity to the induction of apoptosis and enhances imatinib cell kill in CML cells. CCN3 may provide an additional therapeutic strategy in the management of CML

    NOV story: the way to CCN3

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    The principal aim of this historical review- the first in a new series- is to present the basic concepts that led to the discovery of NOV and to show how our ideas evolved regarding the role and functions of this new class of proteins. It should prove particularly useful to the new comers and to students who are engaged in this exciting field. It is also a good opportunity to acknowledge the input of those who participated in the development of this scientific endeavou

    An AFM study of solid-phase bilayers of unsaturated PC lipids and the lateral distribution of the transmembrane model peptide WALP23 in these bilayers

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    An altered lipid packing can have a large influence on the properties of the membrane and the lateral distribution of proteins and/or peptides that are associated with the bilayer. Here, it is shown by contact-mode atomic force microscopy that the surface topography of solid-phase bilayers of PC lipids with an unsaturated cis bond in their acyl chains shows surfaces with a large number of line-type packing defects, in contrast to the much smoother surfaces observed for saturated PC lipids. Di-n:1-PC (n = 20, 22, 24) and (16:0,18:1)-PC (POPC) were used. Next, the influence of an altered lipid environment on the lateral distribution of the single α-helical model peptide WALP23 was studied by incorporating the peptide in the bilayers of di-n:1-PC (n = 20, 22, 24) and (16:0,18:1)-PC unsaturated lipids. The presence of WALP23 leads to an increase in the number of packing defects but does not lead to the formation of the striated domains that were previously observed in bilayers of saturated PC lipids and WALP. This is ascribed to the less efficient lateral lipid packing of the unsaturated lipids, while the increase in packing defects is probably an indirect effect of the peptide. Finally, the fact that an altered lipid packing affects the distribution of WALP23 is also confirmed in an additional experiment where the solvent TFE (2,2,2-trifluorethanol) is added to bilayers of di-16:0-PC/WALP23. At 3.5 vol% TFE, the previous striated ordering of the peptide is abolished and replaced by loose lines

    Operational continental-scale land cover mapping of Australia using the Open Data Cube

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    To comprehensively support national and international initiatives for sustainable development, land cover products need to be reliably and routinely generated within operational frameworks. Coupled with consistent semantics and taxonomies, ensuring confidence in mapping land cover for multiple time periods, facilitates informed decision-making at scales appropriate to multiple policy domains. The United Nations Food and Agriculture Organisation (FAO) Land Cover Classification System (LCCS) provides a taxonomy that comparable at different scales, level of detail and geographic location. The Open Data Cube (ODC) initiative offers a framework for operational continental scale land cover mapping using analysis-ready Earth Observation data. This study utilised the FAO LCCS framework and the Landsat sensor data through Digital Earth Australia (DEA; Australia’s ODC instance) to generate consistent and continent-wide land cover mapping (DEA Land Cover) of the Australian continent. DEA Land Cover provides annual maps from 1988 to 2020 at 25 m resolution. Output maps were validated with ∼12,000 independent validation points, giving an overall map accuracy of 80%. DEA Land Cover provides Australia with a nationally consistent picture of land cover, with an open-source software package using readily available global coverage data and demonstrates a pathway of adoption for national implementations across the worl

    Characterization of the Prokaryotic Sodium Channel NavSp Pore with a Microfluidic Bilayer Platform

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    This paper describes the use of a newly-developed micro-chip bilayer platform to examine the electrophysiological properties of the prokaryotic voltage-gated sodium channel pore (NavSp) from Silicibacter pomeroyi. The platform allows up to 6 bilayers to be analysed simultaneously. Proteoliposomes were incorporated into suspended lipid bilayers formed within the microfluidic bilayer chips. The chips provide access to bilayers from either side, enabling the fast and controlled titration of compounds. Dose-dependent modulation of the opening probability by the channel blocking drug nifedipine was measured and its IC50 determined
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