CULTURABLE PROTEOLYTIC BACTERIA AND THE ACTIVITY OF LEUCINE AMINOPEPTIDASE IN RIVER ECOSYSTEM

摘要

The study determined the numbers and distribution of culturable heterotrophic and proteolytic bacteria and the level of leucine aminopeptidase activity in the water of the Slupia River within the town of Slupsk (Northern Poland). River Slupia is 138.6 km long and flowing into the Baltic Sea. The average water discharge of the river is 15.5 m~as13nd its~ slope is() abou-t 1.3% which gives it a mountainous character. The numbers of culturable heterotrophic bacteria was determined on iron-peptone agar (IPA) medium and the numbers of culturable proteolytic bacteria was assayed in IPA medium enriched with gelatin. Potential leucine aminopeptidase activity was carried out with the use of fluorescently labelled model substrate MCA-leucine. The numbers of heterotrophic bacteria ranged between 0.33 to 183.0 × 10~ 3 cell (maximum in spring, minimum in winter); the abundance of culturable proteolytic bacteria ranged 0.50 to 31.8 × 10~3 cells cm~(-3) and the maximum was noted in spring, the lowest in summer. The activity of extracellular leucine aminopeptidase ranged from 2.34 to 6.87 μM MCA dm~(-3) h~(-1) and the h)ighest value was noted in spring while the lowest were noted in winter and summer. The values of bacteriological parameters and of leucine aminopepidase activity tended to be higher below the sewage treatment plant. The bacteriological parameters for River Slupia were compared with the relevant data for other river ecosystems.