E. Ringo et al., Epithelium-associated bacteria in the gastrointestinal tract of Arctic charr (Salvelinus alpinus L.). An electron microscopical study, J APPL MICR, 90(2), 2001, pp. 294-300
Aims: The primary aim tvas to use transmission electron microscopy (TEM) an
d scanning electron microscopy (SEM) to define the location of epithelium-a
ssociated bacteria in the digestive tract: of the salmonid fish, Arctic cha
rr (Salvelinus alpinus).
Methods and Results: TEM and SEN examination of the gastrointestinal tract
demonstrated substantial numbers of ovoid and rod-shaped bacterial cells as
sociated with the microvillous brush borders of enterocytes. Bacteria were
found at the tips of microvilli as well as between adjacent microvilli. End
ocytosis of bacteria by epithelial cells was observed in two regions (pylor
ic caeca and midgut).
Conclusions: Electron microscope examination of the gut is an important too
l for evaluating the microbial ecology of the fish digestive tract ecosyste
m.
Significance and Impact of the Study: The results of the current study clea
rly demonstrate that the intestine is involved in bacterial endocytosis.