Electronic Resource
Oxford, UK
:
Blackwell Publishing Ltd
FEMS microbiology ecology
25 (1998), S. 0
ISSN:
1574-6941
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
Bacterivorous protozoa secrete glucosaminidase enzymes which digest peptidoglycans in bacterial cell walls. Phagotrophic protozoa store digestive enzymes in lysosomes before release into food vacuoles where digestion takes place initially at acidic pH. The quantity of glucosaminidase can be assayed by measuring the rate of formation of the fluorescent product 4-methylumbelliferone by cleavage of 4-methylumbelliferyl-n-acetyl-β-d-glucosaminide. Flagellate and ciliate cells lysed with detergent possessed glucosaminidase activity which remained steady over at least 24 h. The enzyme activity increased in direct proportion to the biomass for each species tested, although the level of activity varied in different species in a way that probably relates to the ecological strategy of the species. Heterotrophic nanoplankton sampled at eight stations in waters of widely different trophic status along an Atlantic Meridional Transect showed a very strong correlation between glucosaminidase activity and estimated biomass. We conclude that this calibrated glucosaminidase assay can provide a quick and effective method of estimating the biomass of heterotrophic nanoplankton.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1574-6941.1998.tb00463.x
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