1. The cellular proteins of Butyrivibrio fibrisolvens, Lactobacillus casei, Megasphaera elsdenii, Selenomonas ruminantium and Streptococcus bovis were labelled by growth in the presence of L-[14C]leucine, and the breakdown of labelled protein was measured in incubations of these bacteria with rumen fluid to which unlabelled 5 mM-L-leucine was added. The rate of protein breakdown was estimated f...

Protistan assemblages of aquatic ecosystems are the focus of extensive research in aquatic ecology. One stimulus for this work has been the long-standing recognition that phototrophic protists (the unicellular algae) constitute a major fraction of the primary productivity within aquatic ecosystems. Another incentive has been the realization that protozoa (heterotrophic protists) play a pivotal ...

The predation of a luminescence-marked strain of Pseudomonas fluorescens by the soil ciliate Colpoda steinii was studied in soil microcosms. Bacterial cells were introduced in either small (neck diameter, <6 (mu)m) or intermediate-sized (neck diameter, 6 to 30 (mu)m) pores in the soil by inoculation at appropriate matric potentials, and ciliates were introduced into large pores (neck diameter, ...

We have previously demonstrated conjugation of Escherichia coli into vacuoles of the protozoal ciliate (Tetrahymena thermophila). This indicated a possible role of ciliates in evoking bacterial quorum sensing, directly connecting bacterial survival via accumulation in the ciliate vacuoles. We therefore assessed if ciliates promoted bacterial autoinducer (AI)-2 accumulation with vacuole formatio...

In Andean lakes a distinctive assemblage of large mixotrophic ciliates (>80 μm), dominated by the peritrich Ophrydium naumanni Pejler and the heterotrich Stentor araucanus Foissner & Wölfl, has been previously reported (Wölfl, 1995; Modenutti, 1997; Queimaliños et al., 1999; Modenutti et al., 2000). These two species have been found only in large, deep ultra-oligotrophic lakes (area >5 km2, Zma...