Advertisement

Limnology

, Volume 3, Issue 1, pp 47–50 | Cite as

A new method using enhanced green fluorescent protein (EGFP) to determine grazing rate on live bacterial cells by protists

  • N. Ishii
  • H. Takeda
  • M. Doi
  • S. Fuma
  • K. Miyamoto
  • K. Yanagisawa
  • Z. Kawabata
NOTE

Abstract

A new method was developed for estimating the grazing rate of live bacteria by protists. Bacterial cells (Escherichia coli bearing plasmid pEGFP) expressing enhanced green fluorescent protein (EGFP) were used as a live bacterial tracer. Ciliates (Tetrahymena thermophila) were fed with EGFP-tagged bacterial cells, and the individual cells taken up by the ciliates were detected by epifluorescence microscopy. The EGFP fluorescence was stable during the storage of samples fixed with glutaraldehyde. Comparison of clearance rates based on the uptake of EGFP-tagged live cells and fluorescently-labeled heat-killed cells suggested that the use of heat-killed cells underestimates the clearance rates. We suggest that EGFP-tagged bacteria are a useful tracer for determining protist bacterivory in culture and aquatic environments.

Key words Grazing Live bacteria Green fluorescent protein 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Copyright information

© The Japanese Society of Limnology 2002

Authors and Affiliations

  • N. Ishii
    • 1
  • H. Takeda
    • 2
  • M. Doi
    • 2
  • S. Fuma
    • 2
  • K. Miyamoto
    • 2
  • K. Yanagisawa
    • 2
  • Z. Kawabata
    • 3
  1. 1.National Institute of Radiological Sciences, Environmental and Toxicological Sciences Research Group, Model Ecosystem Studies, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan Tel. +81-43-206-3156; Fax +81-45-251-4853 e-mail: nobu@nirs.go.jpJP
  2. 2.Environmental and Toxicological Sciences Research Group, National Institute of Radiological Sciences, Chiba, JapanJP
  3. 3.Center for Ecological Research, Kyoto University, Otsu, JapanJP

Personalised recommendations