Open AccessAssimilation efficiency of Vibrio bacterial protein biomass by the flagellate Pteridomonas : Assessment using flow cytometric sorting
Author(s) -
Zubkov Mikhail V.,
Sleigh Michael A.
Publication year - 2005
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1016/j.femsec.2005.04.001
Subject(s) - flagellate , biology , assimilation (phonology) , vibrio , biomass (ecology) , microbiology and biotechnology , bacteria , heterotroph , bacteriology , biochemistry , botany , ecology , linguistics , philosophy , genetics
A flow cytometric sorting technique for direct determination of bacterial biomass assimilation by phagotrophic flagellates was developed and tested in laboratory culture experiments. Living Vibrio bacteria were quantitatively pulse‐chase labelled with [ 35 S]methionine tracer and fed to Pteridomonas flagellates. Flow sorting revealed that the isotopically labelled material is in either bacterial prey or flagellate predators and the egested bacterial debris contained negligible amounts of tracer. These experimental results confirm an earlier hypothesis that flagellates release metabolised bacterial proteins primarily in a dissolved form. The assimilation efficiency of the Vibrio protein biomass by Pteridomonas was low, only about 20%, independently of the amount of consumed bacterial biomass, confirming our earlier indirect estimates. Additionally, against expectations that cells decrease their metabolic activity whilst preparing for and engaged in division, we found that the precursor uptake rates by flow sorted bacterial cells at the S + G 2 cell cycle stages were constantly 1.5 times higher than those of cells at the G 1 stage.