The fluorescently labeled algae (FLA) technique using a vital green fluorescent stain CMFDA (5-chloromethylfluorescein diacetate) was applied to investigate the feedlng activities of a field ciliate assemblage on a harmful alga, Heterocapsa circularisquama. Using epifluorescence under interference blue-light excitahon improved the h t a t i o n s noted in the original protocol (Li et al. 1996; ...

Several models for specific excision of micronucleus-specific DNA sequences during macronuclear development in ciliates exist. While the template-guided recombination model suggests recombination events resulting in specific DNA excision and reordering of macronucleus-destined sequences (MDS) guided by a template, there is evidence that an RNA interference-related mechanism is involved in DNA e...

I . Two pairs of Friesian steers were changed from ad lib. to restricted intake of a pelleted barley diet and were maintained on this latter intake for periods of 18 or 25 weeks. The restricted level of intake was 70 g/kg0-73 and was adjusted weekly according to individual live weights. The daily allowance was given in three equal feeds during day-time. 2. After an initial period of 9 weeks on ...

Molecular trees and geochemical markers suggest the divergence of dinoflagellates as early eukaryotes (~650 million years ago), but traditional fossil record cysts (dinocysts) starts during Triassic (~230 ago). A re-evaluation pre-Triassic shows that many acritarchs (microfossils uncertain affinities) are dinocysts representing “missing” evidence. Traditional diagnostic criteria for dinocysts, ...

BACKGROUND Parasite peptidases have been actively studied as vaccine candidates or drug targets for prevention or treatment of parasitic diseases because of their important roles for survival and/or invasion in the host. Like other parasites, the facultative histophagous ciliate Miamiensis avidus would possess peptidases that are closely associated with the invasion into the host tissue and sur...

The annually recurrent spring phytoplankton blooms in freshwater lakes initiate pronounced successions of planktonic ciliate species. Although there is considerable knowledge on the taxonomic diversity of these ciliates, their species-specific interactions with other microorganisms are still not well understood. Here we present the succession patterns of 20 morphotypes of ciliates during spring...

The ability of a ciliate to inactivate bacteriophage was studied because these viruses are known to influence the size and diversity of bacterial populations, which affect nutrient cycling in natural waters and effluent quality in sewage treatment, and because ciliates are ubiquitous in aquatic environments, including sewage treatment plants. Tetrahymena thermophila was used as a representative...

Ciliated protists rearrange their genomes dramatically during nuclear development via chromosome fragmentation and DNA deletion to produce a trimmer and highly reorganized somatic genome. The deleted portion of the genome includes potentially active transposons or transposon-like sequences that reside in the germline. Three independent studies recently showed that transposase proteins of the DD...

In aquatic ecosystems, bacteria are controlled by several organisms in the food chain, such as protozoa, that use them as food source. This study aimed to quantify the ingestion and clearance rates of bacteria by ciliates and heterotrophic nanoflagellates (HNF) in a subtropical freshwater reservoir (Monjolinho reservoir - São Carlos - Brazil) during one year period, in order to verify their imp...

Factors controlling the community composition of marine heterotrophic prokaryotes include organic-C, mineral nutrients, predation, and viral lysis. Two mesocosm experiments, performed at an Arctic location and bottom-up manipulated with organic-C, had very different results in community composition for both prokaryotes and viruses. Previously, we showed how a simple mathematical model could rep...