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Document Server@UHasselt (59.068 recursos)

Repository of the University of Hasselt containing publications in the fields of statistics, computer science, information strategies and material from the Institute for behavioural sciences.

Dept. Chemistry-Biology-Geology (SBG) - Zoology

Mostrando recursos 1 - 20 de 122

  1. The "Falcatae", a new Gondwanan species group of Gieysztoria (Platyhelminthes: Dalyelliidae), with the description of five new species

    VAN STEENKISTE, Niels; TESSENS, Bart; WILLEMS, Wim; Van Mulken, Els; ARTOIS, Tom
    Gieysztoria Ruebush and Hayes, 1939, the most species-rich genus of limnic rhabdocoels (Platyhelminthes: Dalyelliidae), is subdivided into several groups based on stylet morphology. Most taxa are known from the Palearctic and the Neotropics. Very little is known about limnic, free-living flatworms in other tropical and subtropical regions. In this contribution five new species of Gieysztoria are described from India, Australia and South Africa, all former Gondwanan fragments. Gieysztoria garudae n. sp., G. ashokae n. sp. and G. ramayana n. sp. were collected in Goa (India), G. stokesi n. sp. in the Northern Territory (Australia) and G. zuluensis n. sp. in...

  2. How many species in the Southern Ocean? Towards a dynamic inventory of the Antarctic marine species.

    De Broyer, Claude; Danis, Bruno; Allcock, Louise; Angel, Martin V.; Arango, Claudia; Artois, Tom; Barnes, D.; Bartsch, Ilse; Bester, Marthan; Blachowiak-Samolyk, Kasia; Blazewicz, Magda; Bohn, Jens; Brandt, Angelika; Brandao, Simone Nunes; David, Bruno; de Salas, Miguel; Eleaume, Marc; Emig, Christian; Fautin, Daphne; George, Kai-Horst; Gillan, David; Gooday, Andrew; Hopcroft, Russ; Jangoux, Michel; Janussen, Dorte; Koubbi, Philippe; Kouwenberg, Juliana; Kuklinski, Piotr; Ligowski, Ryszard; Lindsay, Dhugal; Linse, Katrin; Longshaw, Matt; Lopez-Gonzalez, Pablo; Martin, Patrick; Munilla, Tomas; Muhlenhardt-Siegel, Ute; Neuhaus, Birger; Norenburg, Jon; Ozouf-Costaz, Catherine; Pakhomov, Evgeny; Perrin, William; Petryashov, Victor; Pena-Cantero, Alvaro; Piatkowski, Uwe; Pierrot-Bults, Annelies; Rocka, Anna; Saiz-Salinas, Jose; Salvini-Plawen, Luitfried; Scarabino, Victor; Schiaparelli, Stefano; Schrodl, Michael; Schwabe, Enrico; Scott, Fiona; Sicinski, Jacek; Siegel, Volker; Smirnov, Igor; Thatje, Sven; Utevsky, Andrei; Vanreusel, Ann; Wiencke, Christian; Woehler, Eric; Zdzitowiecki, Krzysztof; Zeidler, Wolfgang
    The IPY sister-projects CAML and SCAR-MarBIN provided a timely opportunity, a strong collaborative framework and an appropriate momentum to attempt assessing the "Known, Unknown and Unknowable" of Antarctic marine biodiversity. To allow assessing the known biodiversity, SCAR-MarBIN "Register of Antarctic Marine Species (RAMS) was complied and published by a panel of 64 taxonomic experts. Thanks to this outstanding expertise mobilized for the first time, an accurate list of more than 8100 valid species was compiled and up-to-date systematic classification comprising more than 16800 taxon names was established. This taxonomic information is progressively and systematically completed by species occurrence data, provided...

  3. First report of the exotic blue land planarian, Caenoplana coerulea (Platyhelminthes, Geoplanidae), on Menorca (Balearic Islands, Spain)

    Breugelmans, Karin; Quintana Cardona, Josep; ARTOIS, Tom; Jordaens, Kurt; Backeljau, Thierry
    In April 2009 two specimens of a terrestrial flatworm were collected from under a rock in an orchard at Ciutadella de Menorca on the easternmost Balearic island of Menorca (Spain). Their external morphology suggested that both specimens belonged to the invasive blue planarian Caenoplana coerulea, a species which is native to eastern Australia. Sequence data of a fragment of the mitochondrial cytochrome c oxidase subunit I (COI) and of the entire 18S ribosomal RNA confirm its identification. This is one of the first records of the species in Europe where it has only been found in one locality in the...

  4. An epidemiological appraisal of the association between heart rate variability and particulate air pollution: a meta-analysis

    Pieters, Nicky; Plusquin, Michelle; Cox, Bianca; Kicinski, Michal; Vangronsveld, Jaco; Nawrot, Tim S.
    Objective Studies on the association between short-term exposure to ambient air pollution and heart rate variability (HRV) suggest that particulate matter (PM) exposure is associated with reductions in measures of HRV, but there is heterogeneity in the nature and magnitude of this association between studies. The authors performed a meta-analysis to determine how consistent this association is. Data source The authors searched the Pubmed citation database and Web of Knowledge to identify studies on HRV and PM. Study selection Of the epidemiologic studies reviewed, 29 provided sufficient details to be considered. The meta-analysis included 18667 subjects recruited from the population...

  5. New species of Limipolycystis Schilke, 1970 (Rhabdocoela: Kalyptorhynchia: Polycystididae) from the Western Mediterranean

    Artois, Tom; Willems, Wim; Revis, Nathalie; Martens, Paul M.; Schockaert, Ernest
    Five new species of Limipolycystis Schilke, 1970 are described and their morphology is compared to that of the only species known, L. curvitubo Schilke, 1970. L. sicilicula n. sp., L. falx n. sp., L friedae n. sp., L. libra n. sp. and L. wallbergi n. sp. all largely resemble L. curvitubo as to the internal anatomy. They all have a caudally-situated testis and, at least in those species for which good material is available, a seminal receptacle could be seen. This seminal receptacle is tubiform, connecting the bursa with the most proximal part of the oviduct, which is filled with...

  6. Patterns of Diversity in Soft-Bodied Meiofauna: Dispersal Ability and Body Size Matter

    Curini-Galletti, Marco; Artois, Tom; Delogu, Valentina; De Smet, Willem H.; Fontaneto, Diego; Jondelius, Ulf; Leasi, Francesca; Martinez, Alejandro; Meyer-Wachsmuth, Inga; Nilsson, Karin Sara; Tongiorgi, Paolo; Worsaae, Katrine; Todaro, M. Antonio
    Background: Biogeographical and macroecological principles are derived from patterns of distribution in large organisms, whereas microscopic ones have often been considered uninteresting, because of their supposed wide distribution. Here, after reporting the results of an intensive faunistic survey of marine microscopic animals (meiofauna) in Northern Sardinia, we test for the effect of body size, dispersal ability, and habitat features on the patterns of distribution of several groups. Methodology/Principal Findings: As a dataset we use the results of a workshop held at La Maddalena (Sardinia, Italy) in September 2010, aimed at studying selected taxa of soft-bodied meiofauna (Acoela, Annelida, Gastrotricha, Nemertodermatida,...

  7. Placental Mitochondrial DNA Content and Particulate Air Pollution During in Utero Life

    Janssen, Bram; Munters, Elke; Pieters, Nicky; Smeets, Karen; Cox, Bianca; Cuypers, Ann; Fierens, Frans; Penders, Joris; Vangronsveld, Jaco; Gyselaers, Wilfried; Nawrot, Tim S.
    BACKGROUND: Studies emphasize the importance of particulate matter (PM) in the formation of reactive oxygen species and inflammation. We hypothesized that these processes can influence mitochondrial function of the placenta and fetus. OBJECTIVES: We investigated the influence of PM10 exposure during pregnancy on the mitochondrial DNA6content (mtDNA content) of the placenta and umbilical cord blood. METHODS: DNA was extracted from placental tissue (n = 174) and umbilical cord leukocytes (n = 176). Relative mtDNA copy numbers (i.e. mtDNA content) were determined by real6time PCR. Multiple regression models were used to link mtDNA content and in utero exposure to PM10 over...

  8. Physiological and molecular characterisation of cadmium stress in Schmidtea mediterranea

    Plusquin, Michelle; Stevens, An-Sofie; Van Belleghem, Frank; Degheselle, Olivier; Van Roten, Andromeda; Vroonen, Jessica; Blust, Ronny; Cuypers, Ann; Artois, Tom; Smeets, Karen
    The planarian Schmidtea mediterranea is a well-studied model organism for developmental research, because of its stem cell system. This characteristic also provides a unique opportunity to study stress management and the effect of stress on stem cells. In this study, we characterised the stress signature at different levels of biological organization. The carcinogenic metal cadmium was used as a model chemical stressor. We focused on stem cell activity and its interaction with other known stress parameters. Here, we have found that S. mediterranea is able to cope with high internal levels of cadmium. At endpoints such as size and mobility,...

  9. De fotosynthese anders bekeken

    Guedens, Wanda; Reygel, Patrick; Asperges, Michel
    Fotosynthese-experimenten in het secundair onderwijs bleven tot nog toe beperkt tot het afdekken van Pelargoniumbladeren met aluminiumfolie en het ‘bellenexperiment’ met waterpest (Elodea canadensis)1. Het practicum ‘Microscopische waarnemingen van de fotosynthese’ laat echter toe de vorming van zuurstofgas en zetmeel op microscopische schaal te zien en bovendien wordt de kennis over (bio)chemie en biologie hierbij op een zeer hoog niveau van integreren gebracht.

  10. Liver X receptors regulate cholesterol homeostasis in oligodendrocytes

    NELISSEN, Katherine; Mulder, Monique; SMETS, Ilse; TIMMERMANS, Silke; SMEETS, Karen; AMELOOT, Marcel; Hendriks, Jerome J. A.
    Cholesterol synthesis and transport in oligodendrocytes are essential for optimal myelination and remyelination in pathological conditions such as multiple sclerosis. However, little is known about cholesterol homeostasis in the myelin-forming oligodendrocytes. Liver X receptors (LXRs) are nuclear oxysterol receptors that regulate genes involved in cholesterol homeostasis and may therefore play an important role in de- and remyelination. We investigated whether LXRs regulate cholesterol homeostasis in oligodendrocytes. mRNA expression of genes encoding LXR-alpha and LXR-beta and their target genes (ABCA1, ABCG1, ABCG4, apoE, and LDLR) was detected in oligodendrocytes derived from both neonatal and adult rats using quantitative real-time PCR. The...

  11. Reference genes for qPCR assays in toxic metal and salinity stress in two flatworm model organisms

    PLUSQUIN, Michelle; DEGHESELLE, Olivier; CUYPERS, Ann; GEERDENS, Ellen; VAN ROTEN, Andromeda; ARTOIS, Tom; SMEETS, Karen
    The flatworm species Schmidtea mediterranea and Macrostomum lignano have become new and innovative model organisms in stem cell, regeneration and tissue homeostasis research. Because of their unique stem cell system, (lab) technical advantages and their phylogenetic position within the Metazoa, they are also ideal candidate model organisms for toxicity assays. As stress and biomarker screenings are often performed at the transcriptional level, the aim of this study was to establish a set of reference genes for qPCR experiments for these two model organisms in different stress situations. We examined the transcriptional stability of nine potential reference genes (actb, tubb, ck2, cox4, cys, rpl13, gapdh, gm2ap, plscr1) to assess those that...

  12. Vakdidactiek: Seminarie practica en demonstraties biologie en natuurwetenschappen

    Reygel, Patrick; Asperges, Michel; Guedens, Wanda
    Deze bijdrage bevat materiaal voor de organisatie van een uitgebreid seminarie in het domein van de vakdidactiek van de Biologie/Natuurwetenschappen. De beschreven workshop en alle experimenten werden in de loop van meerdere jaren getest en gebruikt in een academische lerarenopleiding in het kader van het opleidingsonderdeel Vakdidactiek Biologie/Chemie aan de UHasselt. Het seminarie of een selectie ervan kan ook gebruikt worden in professionele bacheloropleidingen en mits tekstaanpassingen in het Secundair Onderwijs en dit zowel binnen het meeruren pakket Biologie als Natuurwetenschappen.

  13. Onderwijsmethoden en methodische werkvormen geschikt voor lessen biologie en natuurwetenschappen

    Asperges, Michel; Guedens, Wanda; Reygel, Patrick
    Vakdidactiek en -methodiek zijn bij vakleerkrachten niet erg in trek. Het is zelfs moeilijk om recente vakliteratuur voor Vlaanderen over dit onderwerp te vinden. Rond het jaar 1974 startten, op aandringen van Rijksinspectrice Dr. M. De Ridder en zuster Dr. M. Van Dijck, enkele docenten uit het toenmalige regentaat biologie netoverstijgende vergaderingen rond een mogelijke cursus didactiek en methodologie biologie. Dit zou in 1979 resulteren in een handboek. Vooral Deconinck W. (Asperges M. e.a., 1979) werkte inspirerend. Biologie als schoolvak zou van een louter kennisvak - gericht op het kunnen reproduceren van weetjes - veranderen in een wetenschappelijk verantwoord vak...

  14. De fotosynthese anders bekeken

    Guedens, Wanda; Reygel, Patrick; Asperges, Michel
    Fotosynthese-experimenten in het secundair onderwijs bleven tot nog toe beperkt tot het afdekken van pelargoniumbladeren met aluminiumfolie en het ‘bellenexperiment’ met waterpest (Elodea canadensis). Het practicum microscopische waarnemingen van de fotosynthese laat echter toe de vorming van zuurstofgas en zetmeel op microscopische schaal te zien en bovendien wordt de kennis over (bio)chemie en biologie hierbij op een zeer hoog niveau van integreren gebracht.

  15. Contrasting colonization and plant growth promoting capacity between wild type and a gfp-derative of the endophyte Pseudomonas putida W619 in hybrid poplar

    Weyens, Nele; Boulet, Jana; Adriaensen, Kristin; Timmermans, Jean-Pierre; Prinsen, Els; Van Oevelen, Sandra; D'Haen, Jan; Smeets, Karen; Van Der Lelie, Daniel; Taghavi, Safiyh; Vangronsveld, Jaco
    Abstract This study aims to investigate the colonization of poplar by the endophyte Pseudomonas putida W619 and its capacity to promote plant growth. Poplar cuttings were inoculated with P. putida W619 (wild-type or gfp-labelled). The colonization of both strains was investigated and morphological, physiological and biochemical parameters were analyzed to evaluate plant growth promotion. Inoculation with P. putida W619 (wild-type) resulted in remarkable growth promotion, decreased activities of antioxidative defence related enzymes, and reduced stomatal resistance, all indicative of improved plant health and growth in comparison with the noninoculated cuttings. In contrast, inoculation with gfplabelled P. putida W619 did not promote growth; it even had a negative effect on plant...

  16. Short rotation coppice culture of willows and poplars as energy crops on metal contaminated agricultural soils

    Ruttens, Ann; Boulet, Jana; Weyens, Nele; Smeets, Karen; Adriaensen, Kristin; Meers, Erik; Van Slycken, Stijn; Tack, F.; Meiresonne, Linda; Thewys, Theo; Witters, Nele; Carleer, Robert; Dupae, Joke; Vangronsveld, Jaco
    Phytoremediation, more precisely phytoextraction, has been placed forward as an environmental friendly remediation technique, that can gradually reduce increased soil metal concentrations, in particular the bioavailable fractions. The aim of this study was to investigate the possibilities of growing willows and poplars under short rotation coppice (SRC) on an acid, poor, sandy metal contaminated soil, to combine in this way soil remediation by phytoextraction on one hand, and production of biomass for energy purposes on the other. Above ground biomass productivities were low for poplars to moderate for willows, which was not surprising, taking into account the soil conditions that...

  17. Decreased placental mitochondrial DNA-content in response to air pollution during in utero life

    Janssen, Bram; Pieters, Nicky; Munters, Elke; Smeets, Karen; Cuypers, Ann; Penders, Joris; Vangronsveld, Jaco; Gyselaers, Wilfried; Nawrot, Tim
    Recent studies have emphasized the importance of PM, and its associated metal components, in the formation of reactive oxygen species (ROS) and inflammation. Mitochondria are the major intracellular sources and primary targets of ROS. Mitochondrial DNA (mtDNA) is particularly vulnerable to ROS-induced damage, resulting in a higher mutation rate that impacts mitochondrial function. Given its multiple essential roles in metabolic pathways, mitochondrial dysfunction (i.e. change in mtDNA-content) is important in fetal development. In utero exposure to environmental factors may influence mitochondrial function which may comprise a mechanism of earlier onset of multifactorial disease such as cardiovascular disease in later life1.

  18. Spermatogenesis and the structure of the testes in Nemertodermatida

    Boone, Mieke; Bert, Wim; Claeys, Myriam; Houthoofd, Wouter; Artois, Tom
    The ultrastructure of the testes in two representatives of the enigmatic taxon Nemertodermatida was studied using transmission electron microscopy. Nemertoderma westbladi has paired testes, which are delineated by lining cells. Within each testis, different follicles, each surrounded by a membrane-like structure, are found. Flagellophora apelti has genuinely follicular testes, consisting of several follicles, each containing a certain stage of spermatogenesis. As the gametes are not enclosed by a structure that can be called a true gonad, the structure of the testes differs from most bilaterian animals, but resembles the organization of gametogenic areas of ctenophores. Each stage of spermatogenesis in...

  19. First record of Nemertodermatida from Belgian marine waters

    Boone, Mieke; HOUTHOOFD, Wouter; Bert, Wim; ARTOIS, Tom
    This research was funded by an aspirant grant to MB provided by the Research Foundation Flanders (FWO). The authors kindly thank the Flemish Marine Institute (VLIZ), especially Andre Cattrijse, for the use of the research vessel "Zeeleeuw", and would like to acknowledge the help of Nathalie De Hauwere (VLIZ) with the map of the sampling points. The sampling campaigns fit within project G.08.208 financed by the Research Foundation-Flanders (FWO-Vlaanderen).

  20. Freshwater Dalyelliidae from the Nearctic (Platyhelminthes, Rhabdocoela): new taxa and records from Ontario, Canada and Michigan and Alabama, USA

    VAN STEENKISTE, Niels; Gobert, Stefan; Davison, Paul; Kolasa, Jurek; ARTOIS, Tom
    Nine taxa of Dalyelliidae Graff, 1908 collected from limnic habitats in Ontario, Canada and Michigan and Alabama, USA are discussed. Two taxa are new to science. Pseudodalyellia alabamensis n. gen. n. sp. has a unique combination of characters (Microdalyellia-type stylet with two proximal heteromorphic axes of different size and two distal axes with long spines flanking a central spiny plate, uterus without uterine sphincter, glandular protrusion in male atrium) and is therefore placed in a new genus. Gieysztoria choctaw n. sp. is strikingly similar to the Amazonian G. chiqchi Damborenea et al., 2005 but differs by having 13 symmetrically arranged,...

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