Lise Ovreås | PubMed Health

PubMed2006

Microbial biogeography: putting microorganisms on the map.

We review the biogeography of microorganisms in light of the biogeography of macroorganisms. A large body of research supports the idea that free-living microbial taxa exhibit biogeographic patterns. Current evidence confirms that, as proposed by the Baas-Becking hypothesis, 'the environment selects' and is, in part, responsible for spatial variation in microbial diversity. However, recent studies also dispute the idea that 'everything is everywhere'. We also consider how the processes that generate and maintain biogeographic patterns in macroorganisms could operate in the microbial world.

Archaea↗

PubMed2004

Phylogenetic analysis of bacterial communities associated with larvae of the Atlantic halibut propose succession from a uniform normal flora.

Halibut, the largest of all flatfishes is a valuable species with a great potential for aquaculture. Bacteria play an important role in regulating the health of the early life stages. The present article is the first broad-range molecular analysis of bacterial communities in larvae of the Atlantic halibut (Hippoglossus hippoglossus). DNA was extracted from larvae, water and silo biofilm from hatcheries in Norway, Scotland, Iceland and Canada. Eubacterial 16S rRNA gene fragments were amplified by polymerase chain reaction (PCR) with broad-range primers. Sequences spanning the hyper variable V3 region representing individual bacterial species were separated into community profiles by denaturing gradient gel electrophoresis (DGGE). The profiles revealed simple communities after hatching and bacterial succession following growth. Sequencing and phylogenetic analysis of excised DGGE bands suggested aerobic heterotrophs related to groups of Pseudomonas, Janthinobacterium and possibly Marinomonas to be the primary colonisers of the larvae. After onset of feeding, fermentative species (Vibrio) were detected as well. Comparative analysis of bacterial communities from different geographical regions indicated that larvae of the Atlantic halibut possess a distinct and specific normal flora.

Animals↗