Epithelium-associated bacteria in the gastrointestinal tract of Arctic charr (Salvelinus alpinus L.). An electron microscopical study.
OBJECTIVE
The primary aim was to use transmission electron microscopy (TEM) and scanning electron microscopy (SEM) to define the location of epithelium-associated bacteria in the digestive tract of the salmonid fish, Arctic charr (Salvelinus alpinus).


RESULTS
TEM and SEM examination of the gastrointestinal tract demonstrated substantial numbers of ovoid and rod-shaped bacterial cells associated with the microvillous brush borders of enterocytes. Bacteria were found at the tips of microvilli as well as between adjacent microvilli. Endocytosis of bacteria by epithelial cells was observed in two regions (pyloric caeca and midgut).


CONCLUSIONS
Electron microscope examination of the gut is an important tool for evaluating the microbial ecology of the fish digestive tract ecosystem.


CONCLUSIONS
The results of the current study clearly demonstrate that the intestine is involved in bacterial endocytosis.
Ringø
E
E
Department of Arctic Veterinary Medicine, The Norwegian School of Veterinary Science, NO-9292 Tromsø, Norway. einar.ringo@veths.no
Lødemel
J B
JB
Myklebust
R
R
Kaino
T
T
Mayhew
T M
TM
Olsen
R E
RE
D000818:Animals; D001419:Bacteria / Q000648:ultrastructure*; D004064:Digestive System / Q000166:cytology / Q000382:microbiology* / Q000648:ultrastructure; D004705:Endocytosis; D020895:Enterocytes / Q000382:microbiology* / Q000648:ultrastructure*; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D017858:Salmoniformes / Q000382:microbiology*