<abstract xmlns="http://www.w3.org/1999/xhtml"><p>Two short-term (24 h and 48 h) microcosm experiments using natural waters from three eutrophic lakes (Masurian Lake District, Poland) were performed to assess the impact of eukaryotic inhibitors (a combination of cycloheximide and colchicine) on the abundance of nanoflagellates and small ciliates in the &lt;15 µm fraction. The results showed that eukaryotic inhibitors were not completely effective against either group of protists; however, they reduced their numbers considerably. At 24 h of the experiment, 41, 15, and 7% of nanoflagellate and 48, 23, and 3% of ciliate abundances were not lysed, depending on the lake from which water was taken. However, after 48 h of incubation, only below 7% of nanoflagellates and 33, 40, and 17% of ciliates were present in the treatments with inhibitors. Our results suggest that inhibitors may indirectly change bacterial growth and activity, but they do not definitively inhibit these processes. It was concluded that eukaryotic inhibitors are more effective against small nanoflagellates than larger nanoflagellates and ciliates. Concentrations of inhibitors higher than 200 and 100 mg l<sup>−1</sup> for cycloheximide and colchicine, respectively, and an incubation time longer than 24 h also seemed to be more appropriate to achieve the complete inhibition of protists.</p></abstract>

Two short-term (24 h and 48 h) microcosm experiments using natural waters from three eutrophic lakes (Masurian Lake District, Poland) were performed to assess the impact of eukaryotic inhibitors (a combination of cycloheximide and colchicine) on the abundance of nanoflagellates and small ciliates in the <15 µm fraction. The results showed that eukaryotic inhibitors were not completely effective against either group of protists; however, they reduced their numbers considerably. At 24 h of the experiment, 41, 15, and 7% of nanoflagellate and 48, 23, and 3% of ciliate abundances were not lysed, depending on the lake from which water was taken. However, after 48 h of incubation, only below 7% of nanoflagellates and 33, 40, and 17% of ciliates were present in the treatments with inhibitors. Our results suggest that inhibitors may indirectly change bacterial growth and activity, but they do not definitively inhibit these processes. It was concluded that eukaryotic inhibitors are more effective against small nanoflagellates than larger nanoflagellates and ciliates. Concentrations of inhibitors higher than 200 and 100 mg l−1 for cycloheximide and colchicine, respectively, and an incubation time longer than 24 h also seemed to be more appropriate to achieve the complete inhibition of protists.

Changes in protistan abundance and bacterial activity in response to the addition of eukaryotic inhibitors to natural lake water

Department of Microbial Ecology and Environmental Biotechnology, Faculty of Biology

Fisheries & Aquatic Life

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Two short-term (24 h and 48 h) microcosm experiments using natural waters from three eutrophic lakes (Masurian Lake District, Poland) were performed to assess...

Changes in protistan abundance and bacterial activity in response to the addition of eukaryotic inhibitors to natural lake water

Published Online: Jul 27, 2020

Page range: 52 - 61

Received: Feb 05, 2020

Accepted: Mar 31, 2020

DOI: https://doi.org/10.2478/aopf-2020-0008

Keywords
Bacterial activity, Ciliates, Eukaryotic inhibitors, Eutrophic lakes, Nanoflagellates

© 2020 Krystyna Kalinowska et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Changes in protistan abundance and bacterial activity in response to the addition of eukaryotic inhibitors to natural lake water

Published Online: Jul 27, 2020

Page range: 52 - 61

Received: Feb 05, 2020

Accepted: Mar 31, 2020

DOI: https://doi.org/10.2478/aopf-2020-0008

KeywordsBacterial activity, Ciliates, Eukaryotic inhibitors, Eutrophic lakes, Nanoflagellates

© 2020 Krystyna Kalinowska et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
Bacterial activity, Ciliates, Eukaryotic inhibitors, Eutrophic lakes, Nanoflagellates