SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "hsv:(NATURVETENSKAP) hsv:(Biologiska vetenskaper) ;lar1:(lnu)"

Sökning: hsv:(NATURVETENSKAP) hsv:(Biologiska vetenskaper) > Linnéuniversitetet

  • Resultat 1-4 av 4
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Gillman, Anna, et al. (författare)
  • Oseltamivir-Resistant Influenza A (H1N1) Virus Strain with an H274Y Mutation in Neuraminidase Persists without Drug Pressure in Infected Mallards
  • 2015
  • Ingår i: Applied and Environmental Microbiology. - : American Society for Microbiology. - 0099-2240 .- 1098-5336. ; 81:7, s. 2378-2383
  • Tidskriftsartikel (refereegranskat)abstract
    • Influenza A virus (IAV) has its natural reservoir in wild waterfowl and emerging human IAVs often contain gene segments from avian viruses. The active drug metabolite of oseltamivir (oseltamivir carboxylate (OC)), stockpiled as Tamiflu® for influenza pandemic preparedness, is not removed by conventional sewage treatment and has been detected in river water. There, it may there exert evolutionary pressure on avian IAV in waterfowl, resulting in development of resistant viral variants. A resistant avian IAV can circulate among wild birds only if resistance does not restrict viral fitness and if the resistant virus can persist without continuous drug pressure. In this in vivo Mallard (Anas platyrhynchos) study we tested if an OC-resistant avian IAV strain (A(H1N1)/NA-H274Y) could retain resistance while drug pressure was gradually removed. Successively infected Mallards were exposed to decreasing levels of OC, and fecal samples were analyzed for neuraminidase sequence and phenotypic resistance. No reversion to wild-type virus was observed during the experiment, which included 17 days of viral transmission in 10 ducks exposed to OC concentrations below resistance induction levels. We conclude that resistance in avian IAV, induced by OC exposure of the natural host, can persist in absence of the drug. Thus, there is a risk that human pathogenic IAVs that evolve from IAVs circulating among wild birds may contain resistance mutations. An oseltamivir resistant pandemic IAV would be a substantial public health threat. Therefore, our observations underscore the need for prudent oseltamivir use, upgraded sewage treatment and resistance surveillance of IAV in wild birds.
  •  
2.
  • Jönsson, K. Ingemar, 1959-, et al. (författare)
  • Sexual patterns of prebreeding energy reserves in the common frog Rana temporaria along a latitudinal gradient
  • 2009
  • Ingår i: Ecography. - : Wiley-Blackwell. - 0906-7590 .- 1600-0587. ; 32:5, s. 831-839
  • Tidskriftsartikel (refereegranskat)abstract
    • The ability to store energy is an important life history trait for organisms facing long periods without energy income, and in particular for capital breeders such as temperate zone amphibians, which rely on stored energy during reproduction. However, large scale comparative studies of energy stores in populations with different environmental constraints on energy allocation are scarce. We investigated energy storage patterns in spring (after hibernation and before reproduction) in eight common frog (Rana temporaria) populations exposed to different environmental conditions along a 1600 km latitudinal gradient across Scandinavia (range of annual activity period 3-7 months). Analyses of lean body weight (eviscerated body mass), weight of fat bodies, liver weight, and liver fat content, showed that (i) post-hibernation/pre-breeding energy stores increased with increasing latitude in both sexes, (ii) males generally had larger energy reserves than females and (iii) the difference in energy stores between sexes decreased towards the north. Larger energy reserves towards the north can serve as a buffer against less predictable and/or less benign weather conditions during the short activity period, and may also represent a risk-averse tactic connected with a more pronounced iteroparous life history. In females, the continuous and overlapping vitellogenic activity in the north may also demand more reserves in early spring. The general sexual difference could be a consequence of the fact that, at the time of our sampling, females had already invested their energy into reproduction in the given year (i.e. their eggs were already ovulated), while the males' main reproductive activities (e.g. calling, mate searching, sexual competition) occurred later in the season.
  •  
3.
  • Tolf, Conny, et al. (författare)
  • Individual variation in influenza A virus infection histories and long-term immune responses in mallards
  • 2013
  • Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:4, s. e61201-
  • Tidskriftsartikel (refereegranskat)abstract
    • Wild dabbling ducks (genus Anas) are the main reservoir for influenza A virus (IAV) in the Northern Hemisphere. Current understanding of disease dynamics and epidemiology in this virus-host system has primarily been based on populationlevel ,surveillance studies and infection experiments conducted in laboratory settings. Using a combined experimentalnatural approach with wild-strain captive mallards (Anas platyrhynchos), we monitored individual IAV infection histories and immunological responses of 10 birds over the course of 15 months. This is the first detailed study to track natural IAV infection histories over several seasons amongst the same individuals growing from juvenile to adults. The general trends in the infection histories of the monitored birds reflected seasonal variation in prevalence at the population level. However, within the study group there were significant differences between individuals in infection frequency as well as in short and long term anti-IAV antibody response. Further observations included individual variation in the number of infecting virus subtypes, and a strong tendency for long-lasting hemagglutinin-related homosubtypic immunity. Specifically, all infections in the second autumn, except one, were of different subtypes compared to the first autumn. The variation among birds concerning these epidemiologically important traits illustrates the necessity for IAV studies to move from the level of populations to examine individuals in order to further our understanding of IAV disease and epidemiology.
  •  
4.
  • Svensson, Henric, et al. (författare)
  • Acute toxic effects caused by leachate from five different tree species on Artemia Salina and Vibro Fischeri
  • 2012
  • Ingår i: Journal of Biobased Materials and Bioenergy. - : American Scientific Publishers. - 1556-6560 .- 1556-6579. ; 6:2, s. 214-220
  • Tidskriftsartikel (refereegranskat)abstract
    • In this study, leachates resulting from leaching tests carried out with sawdust from five tree species were investigated. The studied species were: Pedunculate oak (Quercus robur), Scots pine (Pinus sylvestris), European larch (Larix decidua), Norway spruce (Picea abies) and European beech (Fagus sylvatica). The analyses included chemical parameters such as pH, TOC and phenolic compounds (reported as total poly-phenols) and acute toxicity on two different organisms, the crustacean Artemia salina and the bacteria Vibro fischeri (Microtox®). There are very high amounts of different phenolic compounds in the leachate, and large differences between tree species. The leachates produced by sawdust and bark of different tree species presented great variation regarding acute toxicity. V. fischeri was more sensitive than A. salina and leachates from pine sawdust and pine bark produced the highest toxicity response from V. fischeri. This study indicates that bark is one component of the tree anatomy that needs to be handled as a potential hazardous material to the aquatic environment. The large variation in toxicity presented by different tree species need to be taken into account when assessing the impacts to surrounding watercourses and constructing wastewater treatment facilities for the wood-based industry such as irrigation water, stormwater runoff from storage areas.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-4 av 4

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy