Effect of protistan grazing on the frequency of dividing cells in bacterioplankton assemblages

Article Abstract:

Bacteriovorous protists are found to control bacterioplankton populations, partly by preferentially feeding on dividing cells. This may explain the persistence of slow-growing cells in bacterioplankton assemblages. The ungrazed populations were larger and the frequency of dividing cells was higher, with increases in this parameter usually preceding increases in biovolume. The grazed populations were characterized by lower total biomasses, lower frequencies of dividing cells and smaller average cell sizes compared with those in nongrazed assemblages.

author: Sherr, Barry F., Sherr, Evelyn B., McDaniel, Julie
Plankton research

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Bacterivory rate estimates and fraction of active bacterivores in natural protist assemblages from aquatic systems

Article Abstract:

An investigation of the fraction of protists in natural assemblages which are actually involved in bacterivory during a particular time period hasindicated that a substantial fraction of the heterotrophic nanoflagellates in natural assemblages might not be feeding on bacteria during a given time period. A new portocol for estimating ingestion rates by natural assemblages of protists that may simplify the cumbersome task of counting ingested labeled bacterial surrogates in protist grazers is proposed.

author: Gonzalez, Juan M.
Physiological aspects, Bacteria, Biotic communities

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Fully automatic determination of soil bacterium numbers, cell volumes, and frequencies of dividing cells by confocal laser scanning microscopy and image analysis

Article Abstract:

An image analysis system facilitates the fully automatic determination of cell number, widths, lengths and volumes of bacteria in soil smears. Use of confocal laser scanning microscope helps surmount the problem of the thickness of the soil smear. The image analysis system helps evaluate the number of cell in agglomerates and the frequency of dividing cells.

author: Shepherd, John, Bloem, Jaap, Veninga, Meint
Observations, Soil microbiology, Cell research, Cytological research

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subjects list: Research, Analysis, Protista, Protists
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