Abstract
Ligh emitted by the bioluminescent bacterium, Xenorhabdus luminescens (isolated from a nematode host), can be measured to monitor reductions of these bacteria in the presence of phagotrophs. X. luminescens is relatively large (0.6 ¢ 3 μm), but comparable in size to many cyanobacteria. We used the light emission method to examine phagotroph feeding on X. luminescens using uni-specific cultures of two chrysomonads, Ochromonas sp. and Spulemma sp. From light decay rates in control and experimental vials, we computed an apparent filtration rate (FR); then, for a concentration (C) of 1 · 106 bacteria ml-1, we estimated capture rate (CR) as FR · C. The Ochromonas sp. did not ingest the bacterium. The maximum estimated FR for Spumella, observed at 6.0 · 103 flagellates ml-1 (medium density), was 0.37 ml h-1, for a volume-specific clearance rate (FR/cell volume) of 7.9 · 105 h-1 and a CR of 62 bacteria · flagellate-1 h-1. Video microscopy indicated these were accurate estimates of capture rates. Microscopic counts were used to monitor growth of a flagellate, Spumella sp., on X. luminescens as the sole food supply. The flagellate doulbed in number every 3.2, while consuming bacteria at a rate of 23 bacteria flagellate-1 h-1. The Spumella grazed the bacteria to a minimum of 5 · 105 cells ml-1, a concentration comparable to observed field densities of other bacteria.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 31-39 |
| Number of pages | 9 |
| Journal | FEMS Microbiology Letters |
| Volume | 73 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 1990 |
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All Science Journal Classification (ASJC) codes
- Microbiology
- Molecular Biology
- Genetics
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Use of biolumescent bacteria, Xenorhabdus luminescens, to measure predation on bacteria by freshwater microflagellates. / Seale, Dianne B.; Boraas, Martin E.; Holen, Dale; Nealson, Kenneth H.
In: FEMS Microbiology Letters, Vol. 73, No. 1, 01.1990, p. 31-39.Research output: Contribution to journal › Article
TY - JOUR
T1 - Use of biolumescent bacteria, Xenorhabdus luminescens, to measure predation on bacteria by freshwater microflagellates
AU - Seale, Dianne B.
AU - Boraas, Martin E.
AU - Holen, Dale
AU - Nealson, Kenneth H.
PY - 1990/1
Y1 - 1990/1
N2 - Ligh emitted by the bioluminescent bacterium, Xenorhabdus luminescens (isolated from a nematode host), can be measured to monitor reductions of these bacteria in the presence of phagotrophs. X. luminescens is relatively large (0.6 ¢ 3 μm), but comparable in size to many cyanobacteria. We used the light emission method to examine phagotroph feeding on X. luminescens using uni-specific cultures of two chrysomonads, Ochromonas sp. and Spulemma sp. From light decay rates in control and experimental vials, we computed an apparent filtration rate (FR); then, for a concentration (C) of 1 · 106 bacteria ml-1, we estimated capture rate (CR) as FR · C. The Ochromonas sp. did not ingest the bacterium. The maximum estimated FR for Spumella, observed at 6.0 · 103 flagellates ml-1 (medium density), was 0.37 ml h-1, for a volume-specific clearance rate (FR/cell volume) of 7.9 · 105 h-1 and a CR of 62 bacteria · flagellate-1 h-1. Video microscopy indicated these were accurate estimates of capture rates. Microscopic counts were used to monitor growth of a flagellate, Spumella sp., on X. luminescens as the sole food supply. The flagellate doulbed in number every 3.2, while consuming bacteria at a rate of 23 bacteria flagellate-1 h-1. The Spumella grazed the bacteria to a minimum of 5 · 105 cells ml-1, a concentration comparable to observed field densities of other bacteria.
AB - Ligh emitted by the bioluminescent bacterium, Xenorhabdus luminescens (isolated from a nematode host), can be measured to monitor reductions of these bacteria in the presence of phagotrophs. X. luminescens is relatively large (0.6 ¢ 3 μm), but comparable in size to many cyanobacteria. We used the light emission method to examine phagotroph feeding on X. luminescens using uni-specific cultures of two chrysomonads, Ochromonas sp. and Spulemma sp. From light decay rates in control and experimental vials, we computed an apparent filtration rate (FR); then, for a concentration (C) of 1 · 106 bacteria ml-1, we estimated capture rate (CR) as FR · C. The Ochromonas sp. did not ingest the bacterium. The maximum estimated FR for Spumella, observed at 6.0 · 103 flagellates ml-1 (medium density), was 0.37 ml h-1, for a volume-specific clearance rate (FR/cell volume) of 7.9 · 105 h-1 and a CR of 62 bacteria · flagellate-1 h-1. Video microscopy indicated these were accurate estimates of capture rates. Microscopic counts were used to monitor growth of a flagellate, Spumella sp., on X. luminescens as the sole food supply. The flagellate doulbed in number every 3.2, while consuming bacteria at a rate of 23 bacteria flagellate-1 h-1. The Spumella grazed the bacteria to a minimum of 5 · 105 cells ml-1, a concentration comparable to observed field densities of other bacteria.
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U2 - 10.1016/0378-1097(90)90721-2
DO - 10.1016/0378-1097(90)90721-2
M3 - Article
AN - SCOPUS:0025198334
VL - 73
SP - 31
EP - 39
JO - FEMS Microbiology Letters
JF - FEMS Microbiology Letters
SN - 0378-1097
IS - 1
ER -