Electron microscopical and bacteriological studies on epithelium-associated bacteria in the pyloric caeca of murrel, Channa punctatus (Bloch)

Abstract

Scanning and transmission electron microscopy (SEM and TEM) were used to define the location of epithelium-associated bacteria in the pyloric caeca of the air-breathing fish, murrel (Channa punctatus). SEM of pyloric caeca revealed substantial association of coccoid bacterial cells on the apices and between microvilli of enterocytes. Endocytosis of bacteria by enterocytes was clearly visible in the pyloric caeca by TEM. Five isolated bacterial strains were evaluated for extracellular protease, amylase and cellulase production quantitatively. Out of five isolated bacterial strains, CPC2 exhibited the highest protease, amylase and cellulase activities. The most promising enzyme-producing adherent bacterial strain, CPC2 was identified as Staphylococcus haemolyticus (Accession No. JX656750) by 16S rRNA gene sequence analysis.