Publications by authors named "Weibel B"

Contextualizing evolutionary history and identifying genomic features of an insect that might contribute to its pest status is important in developing early detection and control tactics. In order to understand the evolution of pestiferousness, which we define as the accumulation of traits that contribute to an insect population's success in an agroecosystem, we tested the importance of known genomic properties associated with rapid adaptation in the Colorado potato beetle (CPB), Leptinotarsa decemlineata Say. Within the leaf beetle genus Leptinotarsa, only CPB, and a few populations therein, has risen to pest status on cultivated nightshades, Solanum.

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In Europe, several species of bats, owls and kestrels exemplify highly urbanised, flying vertebrates, which may get close to humans or domestic animals. Bat droppings and bird pellets may have epidemiological, as well as diagnostic significance from the point of view of pathogens. In this work 221 bat faecal and 118 bird pellet samples were screened for a broad range of vector-borne bacteria using PCR-based methods.

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A reverse line blot (RLB) hybridization assay was adapted and applied for equine blood samples collected at the animal hospital of the University of Zurich to determine the presence of piroplasms in horses in Switzerland. A total of 100 equine blood samples were included in the study. The V4 hypervariable region of the 18S rRNA gene was amplified by polymerase chain reaction and analyzed using the RLB assay.

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Ecosystems provide life-sustaining services upon which human civilization depends, but their degradation largely continues unabated. Spatially explicit information on ecosystem services (ES) provision is required to better guide decision making, particularly for mountain systems, which are characterized by vertical gradients and isolation with high topographic complexity, making them particularly sensitive to global change. But while spatially explicit ES quantification and valuation allows the identification of areas of abundant or limited supply of and demand for ES, the accuracy and usefulness of the information varies considerably depending on the scale and methods used.

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In 2010, a multidisciplinary team within the clinical haematology and cellular therapy department of Amiens general hospital set up a project to optimise the care of patients suffering from lymphoma. The setting up of nurse diagnosis announcement consultations, telephone consultations, new clinical nursing practices, in collaboration with the medical teams, integrates new nursing roles in advanced practices in oncology.

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The oncogenic gammaretrovirus Feline leukemia virus (FeLV) has been the leading cause of death among domestic cats until the introduction of efficient diagnostics and vaccines in the late 1980s. So far, no efficient treatment for viremic animals is available. Hence, use of the FeLV model to evaluate antiretroviral therapies applied to HIV is a timely task.

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Objectives: To identify patient-related risk factors of infection and ways of transmission of extended-spectrum betalactamase (ESBL) producing Serratia marcescens in the paediatric intensive care unit (PICU) of Amiens university hospital (France) between June and July 2002.

Methods: Five cases (four pulmonary infected and one stool contaminated symptom-free neonates) and 35 controls, admitted in the PICU, are included. S.

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Mutations in the TP53 tumor suppressor gene are the most common alteration in cancer, and human primary liver cancers related to previous dietary exposure to the mycotoxin aflatoxin B1 (AFB1) exhibit a specific hot spot mutation at TP53 codon 249. We have asked whether the 249 hot spot is related to a particular susceptibility to AFB1 of this TP53 region or whether it is related to a phenotype of the 249S p53 mutant protein. This was addressed by constructing a metabolically competent variant of Saccharomyces cerevisiae strain yIG397 expressing human cytochrome P450 1A2 and P450-reductase and isolating AFB1-induced mutants that failed to express the genomic ADE2 reporter gene.

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Heterocyclic aromatic amines (HAs) represent a class of potent bacterial mutagens and rodent carcinogens which gain their biological activity upon metabolic conversion by phase I and phase II enzymes. Subsequent to cytochrome P450 (CYP)-dependent hydroxylation, mainly catalyzed by CYP1A2, acetylation mediated by the activity of N-acetyltransferase, NAT2, produces the ultimate electrophilic product that may react with DNA. In addition to point mutations observed in HA-exposed cells as genotoxic endpoint in vitro, loss of heterozygosity (LOH) has often been identified in HA-related rodent tumors as another endpoint in vivo.

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Ethyl carbamate is a known carcinogen occurring in fermented food and beverages and is therefore of interest for food safety assurance. We studied the genotoxicity of ethyl carbamate in Salmonella typhimurium, in Saccharomyces cerevisiae and in human lymphoblastoid TK6 cells. In absence of cytochrome P450 enzymes, no ethyl carbamate-mediated genotoxicity was observed in any of the three test systems in the non-cytotoxic range.

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The potent liver carcinogen aflatoxin B1 (AFB1) is metabolized by cytochrome P450 to the mutagenic epoxide. We have observed that activated AFB1 also strongly induced mitotic recombination in the yeast Saccharomyces cerevisiae. To compare the recombinogenicity of AFB1 to its mutagenicity, three metabolically competent S.

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The somatic mutation and recombination test (SMART) in Drosophila melanogaster allows screening of chemicals for genotoxicity in a multicellular organism. In order to correlate data obtained in the SMART with those from genotoxicity tests in rodents, it is important to learn more on the variety of drug-metabolizing enzymes present in this insect and to identify their substrate specificities. In this study we have concentrated on the phase I enzyme cytochrome P450 6A2, which is the first cytochrome P450 cloned from Drosophila.

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The mutagenic activities of aristolochic acid I (AAI) and II (AAII), the two main components of aristolochic acid (AA), were tested for mutagenicity in vivo in a subcutaneous granulation tissue in rats and in vitro in the corresponding freshly isolated and cultured target cells. In vivo at equimolar dose, AAI induced 16 times more 6-thioguanine resistant cells than AAII. Oxygen tension in vitro was adjusted to that found in vivo: in the subcutaneous connective tissue, the pO2 was determined to be 40 +/- 9 mm Hg, which corresponds in vitro to an O2 concentration of 5% in the incubator atmosphere.

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The mutagenic activity of the natural plant product aristolochic acid (AA) was tested in the Granuloma Pouch Assay, which detects gene mutations induced in a subcutaneous granuloma tissue of rats. After direct exposure of the target tissue, AA induced high frequencies of mutants at a relatively low cytostatic/cytotoxic level. AA was more potent that N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) at equimolar doses.

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BrdU tablets were implanted subcutaneously in rats, and BrdU concentrations were determined in the serum. Within 5 hr peak concentrations of 10 micrograms BrdU/ml blood were reached. The influence of BrdU in vivo on cell cycling, DNA synthesis, spontaneous sister chromatid exchange (SCE) frequencies, and gene-mutation frequencies (6-TGr) was determined in freshly isolated cells from a subcutaneous granulation tissue.

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SCEs were induced, in vivo, in cells of a rapidly proliferating subcutaneous granulation tissue, initiated by the formation of a subcutaneous air pouch, on the backs of adult male rats (Granuloma Pouch Assay). 2 days after pouch formation the test compounds were applied, and 24 h later the granulation tissue was excised and dissociated into single cells. Isolated cells were cultured in vitro in media containing BrdU, and SCEs were determined within 24-48 h.

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