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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.

Zoology: Biodiversity and Toxicology

Mostrando recursos 1 - 20 de 43

  1. Revision of Phaenocora Ehrenberg, 1836 (Rhabditophora, Typhloplanidae, Phaenocorinae) with the description of two new species

    HOUBEN, Albrecht; VAN STEENKISTE, Niels; ARTOIS, Tom
    A morphological and taxonomical account of the taxon Phaenocora is provided. An effort was made to locate and study all available material and, where possible, species are briefly re-described. We also describe two new species: Phaenocora gilberti sp. nov. from Cootes Paradise, Ontario, Canada and Phaenocora aglobulata sp. nov. from Prairie Grove, Alabama, USA. Species recognition is based on a combination of both male and female morphology. A comparison of and discussion on all species is given, resulting in a total of 28 valid species, three species inquirendae, five species dubiae, and one nomen nudum. An identification key is provided.

  2. Renal cells exposed to cadmium in vitro and in vivo: normalizing gene expression data

    RAVINDRAN NAIR, Ambily; SMEETS, Karen; KEUNEN, Els; Lee, Wing-Kee; Thévenod, Frank; VAN KERKHOVE, Emmy; CUYPERS, Ann
    Cadmium (Cd) is a toxic metal with a long half-life in biological systems. This half-life is partly as a result of metallothioneins (MTs), metal-binding proteins with a high affinity for Cd. The high retention properties of the kidneys reside in proximal tubular cells that possess transport mechanisms for Cd-MT uptake, ultimately leading to more Cd accumulation. Researchers have studied MT–metal interactions using various techniques including quantitative real-time PCR (qPCR), an efficient tool for quantifying gene expression. Often a poor choice of reference genes, which is represented by their instability and condition dependency, leads to inefficient normalization of gene expression data...

  3. Glutathione and mitochondria determine acute defense responses and adaptive processes in cadmium-induced oxidative stress and toxicity of the kidney

    Ravindran Nair, Ambily; Lee, Wing-Kee; Smeets, Karen; Swennen, Quirine; Sanchez, Amparo; Thévenod, Frank; Cuypers, Ann
    Cadmium (Cd2+) induces oxidative stress that ultimately defines cell fate and pathology. Mitochondria are the main energy-producing organelles in mammalian cells, but they also have a central role in formation of reactive oxygen species, cell injury, and death signaling. As the kidney is the major target in Cd2+ toxicity, the roles of oxidative signature and mitochondrial function and biogenesis in Cd2+-related stress outcomes were investigated in vitro in cultured rat kidney proximal tubule cells (PTCs) (WKPT-0293 Cl.2) for acute Cd2+ toxicity (1–30 µM, 24 h) and in vivo in Fischer 344 rats for sub-chronic Cd2+ toxicity (1 mg/kg CdCl2 subcutaneously,...

  4. Reliable gene expression analysis by reverse transcription-quantitative PCR: reporting and minimizing the uncertainty in data accuracy.

    REMANS, Tony; KEUNEN, Els; BEX, Geert Jan; SMEETS, Karen; VANGRONSVELD, Jaco; CUYPERS, Ann
    Reverse transcription-quantitative PCR (RT-qPCR) has been widely adopted to measure differences in mRNA levels; however, biological and technical variation strongly affects the accuracy of the reported differences. RT-qPCR specialists have warned that, unless researchers minimize this variability, they may report inaccurate differences and draw incorrect biological conclusions. The Minimum Information for Publication of Quantitative Real-Time PCR Experiments (MIQE) guidelines describe procedures for conducting and reporting RT-qPCR experiments. The MIQE guidelines enable others to judge the reliability of reported results; however, a recent literature survey found low adherence to these guidelines. Additionally, even experiments that use appropriate procedures remain subject to individual variation...

  5. Marine Macrostomorpha (Platyhelminthes, Rhabditophora) from the Algarve (Southern Portugal)

    SCHOCKAERT, Ernest
    Ten species of Macrostomorpha were found in marine environments of the Algarve (Portugal). Six of them were found in the Ria Formosa, a vast intertidal euryhaline lagoon system that dominates the most Eastern coast of the Algarve: two unidentified species of Microstomum Schmidt, 1848, Macrostomum cf. rubrocinctum Ax, 1951 and two unidentified species of Macrostomum Schmidt, 1848, Paromalostomum dubium (de Beauchamps, 1927), Paromalostomum minutum Rieger, 1971 and Cylindromacrostomum faroensis n.sp.. Comparison of this species with C. mediterraneum (Ax, 1955) and the species from Venice, considered to be C. mediterraneum by Rieger (1977), leads to the conclusion that the individuals studied...

  6. Toxicity profiles and solvent-toxicant interference in the planarian Schmidtea mediterranea after dimethylsulfoxide (DMSO) exposure

    STEVENS, An-Sofie; PIROTTE, Nicky; PLUSQUIN, Michelle; Willems, Maxime; NEYENS, Thomas; ARTOIS, Tom; SMEETS, Karen
    To investigate hydrophobic test compounds in toxicological studies, solvents like dimethylsulfoxide (DMSO) are inevitable. However, using these solvents, the interpretation of test compound-induced responses can be biased. DMSO concentration guidelines are available, but are mostly based on acute exposures involving one specific toxicity endpoint. Hence, to avoid solvent–toxicant interference, we use multiple chronic test endpoints for additional interpretation of DMSO concentrations and propose a statistical model to assess possible synergistic, antagonistic or additive effects of test compounds and their solvents. In this study, the effects of both short- (1 day) and long-term (2 weeks) exposures to low DMSO concentrations (up to 1000 µl l−1)...

  7. Two new species of Carcharodorhynchus Meixner, 1938 (Platyhelminthes: Rhabdocoela: Schizorhynchidae) from Brazil and Lanzarote

    REYGEL, Patrick; SCHOCKAERT, Ernest; Janssen, Toon; ARTOIS, Tom
    Two new turbellarian species of the kalyptorhynch taxon Carcharodorhynchus (Rhabdocoela: Schizorhynchidae) are described. C. brasiliensis n. sp. from Brazil differs from its congeners by the fact that only the ventral lip of the slightly asymmetrical proboscis bears denticles, arranged into two rows. It is also characterized by a unique combination of features: 10-12 testes arranged in two rows rostrally from the pharynx, elongated seminal vesicles, and the copulatory organ proper being a short cirrus, the distal tip of which is surrounded by a short sclerotized hood. C. worsaae n. sp. stands unique within the genus in that the male system...

  8. Molecular phylogeny of Kalyptorhynchia (Rhabdocoela, Platyhelminthes) inferred from ribosomal sequence data

    TESSENS, Bart; Janssen, Toon; ARTOIS, Tom
    With 556 species described to date, Kalyptorhynchia includes about one-third of all species of rhabdocoel flatworms. In this study, we present the first molecular phylogenetic analysis of this taxon. The final analysis comprises 110 species. These represent 11 of the 17 known families. The largest family (241 known species), Polycystididae, is represented by nine of 10 subfamilies and 33 of the 58 genera. Sequence data from 18S rDNA and 28S rDNA were analysed using maximum likelihood and Bayesian approaches. Of the two taxa traditionally recognised within Kalyptorhynchia, Eukalyptorhynchia and Schizorhynchia, only Schizorhynchia is monophyletic. All eukalyptorhynch families, except Cicerinidae, are...

  9. Revision of Acrochordonoposthia Reisinger, 1924 (Rhabditophora, Typhloplanidae, Protoplanellinae) with the description of one new species

    HOUBEN, Albrecht; Proesmans, Willem; Bert, Wim; ARTOIS, Tom
    An overview of the morphology, taxonomy and distribution of all known species of the rhabdocoel taxon Acrochordonoposthia is provided. One new species A. vandeputae n. sp. is described from Graz (Austria). This new species can easily be distinguished from its congeners by the morphology of its copulatory organ, which contains a straight cirrus lined with spines. All species of Acrochordonoposthia are compared with one another, and an updated identification key is provided.

  10. A new genus with six new species of Typhlopolycystidinae Evdonin, 1977 (Platyhelminthes, Kalyptorhynchia, Polycystididae)

    SCHOCKAERT, Ernest; Martens, Paul M.; REVIS, Nathalie; Janssen, Toon; WILLEMS, Wim; ARTOIS, Tom
    Five new species of the new taxon Brunetorhynchus n. gen. are described: B. deconincki n. sp., B. microstylis n. sp. and B. complicatus n. sp. are from the Mediterranean, B. canariensis n. sp. is from the Canary Island Lanzarote, B. cannoni n. sp. is from the Australian East coast and one species from the Galapagos, formerly described as Limipolycystis spec., is transferred to the new genus as B. dubius n. sp.. As in Limipolycystis, these species have a single stylet, (accessory stylet type II), an accessory secretion vesicle (type II) and a prostate vesicle (type III) in the male atrium,...

  11. Problematic barcoding in flatworms: A case-study on monogeneans and rhabdocoels (Platyhelminthes)

    Vanhove, Maarten P. M.; TESSENS, Bart; Schoelinck, Charlotte; Jondelius, Ulf; Littlewood, D. Tim J.; ARTOIS, Tom; Huyse, Tine
    Some taxonomic groups are less amenable to mitochondrial DNA barcoding than others. Due to the paucity of molecular information of understudied groups and the huge molecular diversity within flatworms, primer design has been hampered. Indeed, all attempts to develop universal flatworm-specific COI markers have failed so far. We demonstrate how high molecular variability and contamination problems limit the possibilities for barcoding using standard COI-based protocols in flatworms. As a consequence, molecular identification methods often rely on other widely applicable markers. In the case of Monogenea, a very diverse group of platyhelminth parasites, and Rhabdocoela, representing one-fourth of all free-living flatworm...



  13. The need for transparency and good practices in the qPCR literature

    Bustin, Stephen A.; Benes, Vladimir; Garson, Jeremy; Hellemans, Jan; Huggett, Jim; Kubista, Mikael; Mueller, Reinhold; Nolan, Tania; Pfaffl, Michael W.; Shipley, Gregory; Wittwer, Carl T.; Schjerling, Peter; Day, Philip J.; Abreu, Monica; Aguado, Begona; Beaulieu, Jean-Francois; Beckers, Anneleen; Bogaert, Sara; Browne, John A.; Carrasco-Ramiro, Fernando; Ceelen, Liesbeth; Ciborowski, Kate; Cornillie, Pieter; Coulon, Stephanie; CUYPERS, Ann; De Brouwer, Sara; De Ceuninck, Leentje; De Craene, Jurgen; De Naeyer, Helene; De Spiegelaere, Ward; Deckers, Kato; Dheedene, Annelies; Durinck, Kaat; Ferreira-Teixeira, Margarida; Fieuw, Annelies; Gallup, Jack M.; Gonzalo-Flores, Sandra; Goossens, Karen; Heindryckx, Femke; Herring, Elizabeth; Hoenicka, Hans; Icardi, Laura; Jaggi, Rolf; Javad, Farzad; Karampelias, Michael; Kibenge, Frederick; Kibenge, Molly; Kumps, Candy; Lambertz, Irina; Lammens, Tim; Markey, Amelia; Messiaen, Peter; Mets, Evelien; Morais, Sofia; Mudarra-Rubio, Alberto; Nakiwala, Justine; Nelis, Hilde; Olsvik, Pal A.; Perez-Novo, Claudina; PLUSQUIN, Michelle; REMANS, Tony; Rihani, Ali; Rodrigues-Santos, Paulo; Rondou, Pieter; Sanders, Rebecca; Schmidt-Bleek, Katharina; Skovgaard, Kerstin; SMEETS, Karen; Tabera, Laura; Toegel, Stefan; Van Acker, Tim; Van den Broeck, Wim; Van der Meulen, Joni; Van Gele, Mireille; Van Peer, Gert; Van Poucke, Mario; Van Roy, Nadine; Vergult, Sarah; Wauman, Joris; Tshuikina-Wiklander, Marina; Willems, Erik; Zaccara, Sara; Zeka, Fjoralba; Vandesompele, Jo
    Two surveys of over 1,700 publications whose authors use quantitative real-time PCR (qPCR) reveal a lack of transparent and comprehensive reporting of essential technical information. Reporting standards are significantly improved in publications that cite the Minimum Information for Publication of Quantitative Real-Time PCR Experiments (MIQE) guidelines, although such publications are still vastly outnumbered by those that do not.

  14. Decreased Mitochondrial DNA Content in Association with Exposure to Polycyclic Aromatic Hydrocarbons in House Dust during Wintertime: From a Population Enquiry to Cell Culture

    PIETERS, Nicky; Koppen, Gudrun; SMEETS, Karen; Napierska, Dorota; PLUSQUIN, Michelle; De Prins, Sofie; Van de Weghe, Hendrik; Nelen, Vera; COX, Bianca; CUYPERS, Ann; Hoet, Peter; Schoeters, Greet; NAWROT, Tim
    Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental pollutants that are formed in combustion processes. At the cellular level, exposure to PAHs causes oxidative stress and/or some of it congeners bind to DNA, which may interact with mitochondrial function. However, the influence of these pollutants on mitochondrial DNA (mtDNA) content remains largely unknown. We determined whether indoor exposure to PAHs is associated with mitochondrial damage as represented by blood mtDNA content. Blood mtDNA content (ratio mitochondrial/nuclear DNA copy number) was determined by real-time qPCR in 46 persons, both in winter and summer. Indoor PAH exposure was estimated by measuring PAHs in...

  15. Brachyrhynchoides nom. nov Artois & Schockaert, 2013: A replaced name for Brachyrhynchus Artois & Schockaert, 2013

    ARTOIS, Tom; WILLEMS, Wim; REYGEL, Patrick; SCHOCKAERT, Ernest

  16. The role of the kinase OXI1 in cadmium- and copper-induced molecular responses in Arabidopsis thaliana

    Smeets, Karen; Opdenakker, Kelly; Remans, Tony; Forzani, Celine; Hirt, Heribert; Vangronsveld, Jaco; Cuypers, Ann
    The hypothesis that mitogen-activated protein kinase (MAPK) signalling is important in plant defences against metal stress has become accepted in recent years. To test the role of oxidative signal-inducible kinase (OXI1) in metal-induced oxidative signalling, the responses of oxi1 knockout lines to environmentally realistic cadmium (Cd) and copper (Cu) concentrations were compared with those of wild-type plants. A relationship between OXI1 and the activation of lipoxygenases and other initiators of oxylipin production was observed under these stress conditions, suggesting that lipoxygenase-1 may be a downstream component of OXI1 signalling. Metal-specific differences in OXI1 action were observed. For example, OXI1 was...

  17. A Comprehensive Molecular Phylogeny of Dalytyphloplanida (Platyhelminthes: Rhabdocoela) Reveals Multiple Escapes from the Marine Environment and Origins of Symbiotic Relationships

    Van Steenkiste, Niels; Tessens, Bart; Willems, Wim; Backeljau, Thierry; Jondelius, Ulf; Artois, Tom
    In this study we elaborate the phylogeny of Dalytyphloplanida based on complete 18S rDNA (156 sequences) and partial 28S rDNA (125 sequences), using a Maximum Likelihood and a Bayesian Inference approach, in order to investigate the origin of a limnic or limnoterrestrial and of a symbiotic lifestyle in this large group of rhabditophoran flatworms. The results of our phylogenetic analyses and ancestral state reconstructions indicate that dalytyphloplanids have their origin in the marine environment and that there was one highly successful invasion of the freshwater environment, leading to a large radiation of limnic and limnoterrestrial dalytyphloplanids. This monophyletic freshwater clade,...

  18. Cadmium-Induced Pathologies: Where Is the Oxidative Balance Lost (or Not)?

    Over the years, anthropogenic factors have led to cadmium (Cd) accumulation in the environment causing various health problems in humans. Although Cd is not a Fenton-like metal, it induces oxidative stress in various animal models via indirect mechanisms. The degree of Cd-induced oxidative stress depends on the dose, duration and frequency of Cd exposure. Also the presence or absence of serum in experimental conditions, type of cells and their antioxidant capacity, as well as the speciation of Cd are important determinants. At the cellular level, the Cd-induced oxidative stress either leads to oxidative damage or activates signal transduction pathways to...

  19. Brachyrhynchus n. gen. n. sp., a new genus of Polycystididae Graff, 1905 (Rhabdocoela: Kalyptorhynchia), with the description of three new species from the Mediterranean and the Indian Ocean

    Artois, Tom; Willems, Wim; Reygel, Patrick; Schockaert, Ernest
    Three new species of Polycystididae are described: Brachyrhynchus triplostylis n. gen. n. sp., B. acutus n. sp. and B. oosterlyncki n. sp. They are the first species of Polycystididae to be described with a second, single-walled accessory stylet connected to a small glandular vesicle in the male system. The three species can be distinguished from each other by the detailed morphology and the relative lengths of the three stylets in the male system. The relationships of these species with other representatives of Polycystididae are discussed.

  20. Placental DNA hypomethylation in assiociation with particulate air pollution in early life

    Janssen, Bram G.; Godderis, Lode; Pieters, Nicky; Poels, Katrien; Kicinski, Michal; Cuypers, Ann; Fierens, Frans; Penders, Joris; Plusquin, Michelle; Gyselaers, Wilfried; Nawrot, Tim S.
    Background There is evidence that altered DNA methylation is an important epigenetic mechanism in prenatal programming and that developmental periods are sensitive to environmental stressors. We hypothesized that exposure to fine particles (PM2.5) during pregnancy could influence DNA methylation patterns of the placenta. Methods In the ENVIRONAGE birth cohort, levels of 5’-methyl-deoxycytidine (5-mdC) and deoxycytidine (dC) were quantified in placental DNA from 240 newborns. Multiple regression models were used to study placental global DNA methylation and in utero exposure to PM2.5 over various time windows during pregnancy. Results PM2.5 exposure during pregnancy averaged (25th-75th percentile) 17.4 (15.4-19.3) μg/m3. Placental global DNA methylation was inversely associated...

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