| 1. |
- Dinasquet, Julie, et al.
(författare)
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Cascading effects of the ctenophore Mnemiopsis leidyi on the planktonic food web in a nutrient-limited estuarine system
- 2012
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Ingår i: Marine Ecology Progress Serie. - : Inter-Research Science Center. - 0171-8630 .- 1616-1599. ; 460, s. 49-61
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Tidskriftsartikel (refereegranskat)abstract
- Increasing biomasses of gelatinous zooplankton presumably have major implications for the structure and function of marine food webs at large; however, current data on lower trophic levels are scarce, as most studies have focused on the immediate effects on zooplankton and fish larvae only. We examined the short-term impact of larvae and adults of the invasive ctenophore Mnemiopsis leidyi on a summer planktonic food web in the estuarine southern Baltic Sea, with special emphasis on the microbial loop. Grazing by M. leidyi reduced the mesozooplankton biomass, followed by increased dinoflagellate biomass in treatments with M. leidyi. While chlorophyll a increased most in the treatments with M. leidyi, small phytoplankton and ciliates decreased in all treatments. M. leidyi had a slight effect on bacterial abundance, but not on bacterial production, ectoenzymatic activities, or community composition. Undetectable levels of phosphate and a gradual accumulation of dissolved organic carbon during the experiment suggested a malfunctioning microbial loop scenario. The experiment shows that direct and indirect short-term effects of M. leidyi on the estuarine food web are limited to higher trophic levels and indicates that top-down and bottom-up consequences of M. leidyi expansions on the microbial loop will likely depend on local nutrient conditions.
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| 2. |
- Fjeldsoe-Nielsen, H, et al.
(författare)
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Phenotypic and genotypic characterization of prolyliminopeptidase-negative Neisseria gonorrhoeae isolates in Denmark.
- 2005
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Ingår i: European Journal of Clinical Microbiology and Infectious Diseases. - : Springer Science and Business Media LLC. - 0934-9723 .- 1435-4373. ; 24:4, s. 280-283
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Tidskriftsartikel (refereegranskat)abstract
- In the study presented here 26 recent Danish clinical isolates of prolyliminopeptidase (PIP)-negative Neisseria gonorrhoeae were phenotypically and genotypically characterized to investigate whether one or more PIP-negative strains are circulating in the Danish community. The profiles of these isolates were compared with those of three isolates from a recent outbreak of PIP-negative N. gonorrhoeae infection in the UK. Twenty-five of the Danish isolates and all three UK isolates had similar antibiograms and were designated serovar IB-4. Genotypic characterization by pulsed-field gel electrophoresis, porB1b gene sequencing, and opa-typing revealed that these isolates were indistinguishable or closely related. The results indicate that at least one PIP-negative N. gonorrhoeae strain is currently circulating in the Danish community, and this strain is indistinguishable from the one that caused an outbreak in the UK.
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| 3. |
- Gambill, M., et al.
(författare)
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Effects of temperature on the feeding and growth of the larvae of the invasive ctenophore Mnemiopsis leidyi
- 2015
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Ingår i: Journal of Plankton Research. - : Oxford University Press (OUP). - 0142-7873 .- 1464-3774. ; 37:5, s. 1001-1005
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Tidskriftsartikel (refereegranskat)abstract
- Carbon-specific prey clearance and ingestion rates of 1.5-mm tentaculate larvae of the ctenophore Mnemiopsis leidyi increased linearly between 6 and 25 degrees C but declined between 25 and 30 degrees C. Both absolute (length) and carbon-specific growth rate increased linearly with increasing temperature. The latter was 0.87 d(-1) at 25 degrees C. Extremely low or negative growth rates observed at 6 and 30 degrees C help define the thermal limits to population growth of this successful biological invader.
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| 4. |
- Midgley, S, et al.
(författare)
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Human group A rotavirus infections in children in Denmark; detection of reassortant G9 strains and zoonotic P[14] strains.
- 2014
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Ingår i: Infection, Genetics and Evolution. - : Elsevier BV. - 1567-7257 .- 1567-1348. ; 27, s. 114-120
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Tidskriftsartikel (refereegranskat)abstract
- One of the leading causes of severe childhood gastroenteritis are group A rotaviruses, and they have been found to be associated with ∼40% of the annual gastroenteritis-associated hospitalizations in young Danish children <5years of age (Fischer et al., 2011). In this study, we investigated the diversity of rotavirus strains circulating among young children <5years of age, presenting with gastroenteritis disease either at the general practitioner or in the hospital, during the period 2009-2013. A total of 831 rotavirus positive stool samples were genotyped in the study period, and the majority of samples (74%) were from hospitalized children. G and P genotypes were successfully determined for 826 of samples, with G1P[8] being the most commonly detected genotype. Detection of G1 showed a decreasing trend over time, and an inverse trend was seen for the emerging G9P. The common human genotypes (G1/G3/G4/G9P[8] and G2P[4]) were detected in the majority of samples (n=733, 88.2%). Rare genotype combinations such as G6P[14] were detected in <1% of samples. Rare genotype strains and strains which failed to amplify in genotyping RT-PCR were subjected to genetic characterization by sequencing one or all of the following genes; VP7, VP4, VP6 and NSP4. Sequences of sufficient length and quality were available for all 4 genes for 28 strains. Phylogenetic analysis revealed that reassortant G9P[4] strains circulated with 3 different genotype combinations. As rotavirus vaccines are not widely used in Denmark or its neighboring countries, the diversity of rotavirus strains identified in this study most likely reflects naturally occurring selection pressures and viral evolution.
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