Startsida
Hjälp
Sök i LIBRIS databas

     

 

Sökning: onr:20402191 > Environmental facto...

Environmental factors selecting for predation resistant and potentially pathogenic bacteria in aquatic environments [Elektronisk resurs] / Peter Mathisen

Mathisen, Peter, 1979- (författare)
Andersson, Agneta (preses)
Thelaus, Johanna (preses)
Forsman, Mats (preses)
Sjöstedt, Anders (preses)
Thingstad, Tron Frede (opponent)
Umeå universitet. Institutionen för ekologi, miljö och geovetenskap (utgivare)
Alternativt namn: Institutionen för ekologi, miljö och geovetenskap, Umeå universitet
Alternativt namn: Institutionen för EMG
Alternativt namn: Engelska: Umeå University. Department of Ecology and Environmental Science
Umeå : Umeå Universitet, 2017
Engelska 28 s.
Läs hela texten (Fritt tillgänglig via Umeå universitet)
Läs hela texten (Fritt tillgänglig via Umeå universitet)
  • E-bokAvhandling(Diss. (sammanfattning) Umeå : Umeå universitet, 2017)
Sammanfattning Ämnesord
Stäng  
  • The long history of co-existence of bacteria and their protozoan predators in aquatic environments has led to evolution of protozoa resistant bacteria (PRB). Many of these bacteria are also pathogenic to humans. However, the ecological drivers determining the occurrence of different types of PRB in aquatic environments, and the eco-evolutionary link between bacterial adaptation and the resulting implications for mammalian hosts are poorly known. This thesis examines the impact of nutrients and predation on PRB, as well as the ecological and evolutionary connection between their life in aquatic environments and mammalian hosts. In the first study seven bacterial isolates from the Baltic Sea were investigated for their plasticity of adaptation to predation. The response to predation showed large variation where some bacteria rapidly developed a degree of grazing resistance when exposed to predators. The rapid adaptation observed may result in bacterial communities being resilient or resistant to predation, and thus rapid adaptation may be a structuring force in the food web. With the aim to elucidate the link between occurrence of PRB and environmental conditions, a field study and a laboratory experiment were performed. In both studies three PRB genera were found: Mycobacterium , Pseudomonas and Rickettsia . PRB were found both in oligotrophic and eutrophic waters, indicating that waters of all nutrient states can harbor pathogenic bacteria. However, the ecological strategy of the PRB varied depending on environmental nutrient level and disturbance. Using an advanced bioinformatic analysis, it was shown that ecotypes within the same PRB genus can be linked to specific environmental conditions or the presence of specific protozoa, cyanobacteria or phytoplankton taxa. These environmental conditions or specific plankton taxa could potentially act as indicators for occurrence of PRB. Finally, using four mutants (with specific protein deletions) of the pathogenic and predation resistant Francisella tularensis ssp. holarctica , I found evidence of an eco-evolutionary connection between the bacterium´s life in aquatic and mammalian hosts (aquatic amoeba Acanthamoeba castellanii and a murine macrophage).  To a large extent F. t. holarctica use similar mechanisms to persist predation by protozoa and to resist degradation by mammal macrophages. To summarize I found a link between predation resistant bacteria in aquatic environments and bacteria that are pathogenic to mammals. Further, I showed that different environmental conditions rapidly selects for PRB with either intracellular or extracellular lifestyles. This thesis provides insights regarding environmental conditions and biomarkers that can be used for assessment of aquatic environments at risk for spreading pathogenic bacteria.   

Ämnesord

Ecology  (hsv)
Ekologi  (hsv)
Bakterier  (sao)
Protozoer  (sao)
Predation  (sao)
Övergödning  (sao)
Predation (Biology)  (LCSH)
Bacteria  (LCSH)
Eutrophication  (LCSH)

Indexterm och SAB-rubrik

Eutrophication
productivity
predation pressure
predation-resistant bacteria
pathogens
Francisella tularensis
adaptation
biomarker
oligotyping

Klassifikation

579.317 (DDC)
Ueca (kssb/8 (machine generated))
Inställningar Hjälp

Titeln finns på 1 bibliotek. 

Bibliotek i norra Sverige (1)

Ange som favorit
Om LIBRIS
Sekretess
Blogg
Hjälp
Fel i posten?
Kontakt
Teknik och format
Sök utifrån
Sökrutor
Plug-ins
Bookmarklet
Anpassa
Textstorlek
Kontrast
Vyer
LIBRIS söktjänster
SwePub
Sondera
Uppsök

Copyright © LIBRIS - Nationella bibliotekssystem

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy