| conserved arrangements of repeated dna sequences in nontranscribed spacers of ciliate ribosomal rna genes: evidence for molecular coevolution. | we have analyzed the nucleotide sequences of the nontranscribed spacer (nts) and transcription initiation and termination regions of the extrachromosomal rdnas of the ciliated protozoans tetrahymena thermophila and glaucoma chattoni. the sequences surrounding the sites of transcription initiation and termination are highly conserved. the only extensive homologies of the nts regions occur in five sets of dispersed repetitive sequences. type i, ii and iii repeats in the 5' nts are strongly conserv ... | 2014 | 3923439 |
| characterization of two types of histone h2b genes from macronuclei of tetrahymena thermophila. | two histone h2b gene clones were isolated from macronuclei of tetrahymena thermophila. nucleotide sequences of the two clones were highly homologous within the coding region but not in the noncoding region. comparison of the deduced amino acid sequences between the two clones showed three differences in a total of 121 amino acids. each of the two clones contained a taa triplet within the coding region, which appeared to code for a glutamine residue. to demonstrate the existence of histone mrna c ... | 2010 | 3039463 |
| polypeptides during early conjugation in tetrahymena thermophila. | as tetrahymena thermophila cells differentiate from their vegetative life cycle to sexual reproduction, their polypeptide pattern undergoes a series of changes. these changes have been traced in extracellular, cellular, and subcellular compartments. the first alteration is induced by the nutritional shift-down and results in stimulation of at least one ciliary polypeptide and affects a series of polypeptides from other compartments. the second alteration is induced by mixing starved cells of com ... | 2013 | 3956587 |
| sequence structures of two developmentally regulated, alternative dna deletion junctions in tetrahymena thermophila. | deletions of specific dna sequences are known to occur in tetrahymena thermophila as a developmentally regulated process. deletions of a particular region (region m) were previously shown to be of two alternative sizes, 0.6 or 0.9 kilobases (kb) (c.f. austerberry, c.d. allis, and m.-c. yao, proc. natl. acad. sci. usa 81: 7383-7387). in this study, the nucleotide sequences for both deletions were determined. these two deletions share the same right junction, but their left junctions are 0.3 kb ap ... | 2011 | 3221871 |
| induction of acquired thermotolerance in tetrahymena thermophila: effects of protein synthesis inhibitors. | when tetrahymena thermophila cells growing at 30 degrees c are shifted to either 40 or 43 degrees c, the kinetics and extent of induction of heat shock mrnas in both cases are virtually indistinguishable. however, the cells shifted to 40 degrees c show a typical induction of heat shock protein (hsp) synthesis and survive indefinitely (100% after 24 h), whereas those at 43 degrees c show an abortive synthesis of hsps and die (less than 0.01% survivors) within 1 h. cells treated at 30 degrees c wi ... | 2013 | 3837855 |
| the internally located telomeric sequences in the germ-line chromosomes of tetrahymena are at the ends of transposon-like elements. | the germ-line micronuclear genome of the ciliate tetrahymena thermophila contains approximately 10(2) chromosome-internal blocks of tandemly repeated c4a2 sequences (mic c4a2). this repeated sequence is the telomeric sequence in the somatic macronucleus. each of six cloned micc4a2 was found to be adjacent to a conserved 30 bp sequence, which we propose is the terminal inverted repeat of a family of dna elements (the tel-1 family). this 30 bp sequence contains a site for the infrequently cutting ... | 2010 | 3000613 |
| induced resistance to 6-methylpurine and cycloheximide in tetrahymena. ii. variation within vegetative cultures of micronucleate t. thermophila and amicronucleate t. pyriformis. | resistance to 6-methylpurine and cycloheximide has been induced in both the micronucleate species tetrahymena thermophila and the amincronucleate species t. pyriformis. resistance follows only after mutagen treatment and vegetative growth. the frequencies with which resistant variants are induced and the independence of mutagenesis and selection are demonstrated. all evidence is consistent with the hypothesis that macronuclear subunits are assorting in both species during vegetative growth to pr ... | 2002 | 150921 |
| the self-splicing rna of tetrahymena is trapped in a less active conformation by gel purification. | when the circular form of the self-splicing intervening sequence of tetrahymena thermophila was purified by denaturing polyacrylamide gel electrophoresis by standard methods, the rate of its reaction with tetrauridylate decreased 150-fold at 30 degrees c and at least 1000-fold at 0 degrees c. the activity of the self-splicing rna was restored by heating it to high temperature and letting it renature in the presence of mg2+. the rate of reaction of tetrauridylate with the self-splicing rna flanke ... | 1996 | 2271667 |
| catalysis of rna cleavage by the tetrahymena thermophila ribozyme. 1. kinetic description of the reaction of an rna substrate complementary to the active site. | a ribozyme derived from the intervening sequence (ivs) of the tetrahymena preribosomal rna catalyzes a site-specific endonuclease reaction: g2cccucua5 + g in equilibrium with g2cccucu + ga5 (g = guanosine). this reaction is analogous to the first step in self-splicing of the pre-rrna, with the product g2cccucu analogous to the 5'-exon. the following mechanistic conclusions have been derived from pre-steady-state and steady-state kinetic measurements at 50 degrees c and neutral ph in the presence ... | 1996 | 2271645 |
| changes in ornithine decarboxylase activity and polyamine levels during the growth of tetrahymena thermophila cultures. | ornithine decarboxylase activity and polyamine levels were determined at various growth phases of tetrahymena thermophila cultures. enzyme activity and intracellular polyamines increased in exponentially growing cells and peaked just before the stationary phase. putrescine was the predominant polyamine and spermidine and spermine concentrations were low throughout. the increase in putrescine level can be totally accounted for by the enzyme activity detected, provided that there is an ample suppl ... | 2014 | 3995923 |
| a novel sterol desaturase-like protein promoting dealkylation of phytosterols in tetrahymena thermophila. | the gene ttherm_00438800 (des24) from the ciliate tetrahymena thermophila encodes a protein with three conserved histidine clusters, typical of the fatty acid hydroxylase superfamily. despite its high similarity to sterol desaturase-like enzymes, the phylogenetic analysis groups des24p in a separate cluster more related to bacterial than to eukaryotic proteins, suggesting a possible horizontal gene transfer event. a somatic knockout of des24 revealed that the gene encodes a protein, des24p, whic ... | 2011 | 21257793 |
| the genealogic tree of mycobacteria reveals a long-standing sympatric life into free-living protozoa. | free-living protozoa allow horizontal gene transfer with and between the microorganisms that they host. they host mycobacteria for which the sources of transferred genes remain unknown. using blastp, we searched within the genomes of 15 mycobacteria for homologous genes with 34 amoeba-resistant bacteria and the free-living protozoa dictyostelium discoideum. subsequent phylogenetic analysis of these sequences revealed that eight mycobacterial open-reading frames (orfs) were probably acquired via ... | 2012 | 22511965 |
| differential growth of and nanoscale tio₂ accumulation in tetrahymena thermophila by direct feeding versus trophic transfer from pseudomonas aeruginosa. | nanoscale titanium dioxide (tio2) is increasingly used in consumer goods and is entering waste streams, thereby exposing and potentially affecting environmental microbes. protozoans could either take up tio2 directly from water and sediments or acquire tio2 during bactivory (ingestion of bacteria) of tio2-encrusted bacteria. here, the route of exposure of the ciliated protozoan tetrahymena thermophila to tio2 was varied and the growth of, and uptake and accumulation of tio2 by, t. thermophila we ... | 2013 | 23851096 |
| identification of aeromonas hydrophila genes preferentially expressed after phagocytosis by tetrahymena and involvement of methionine sulfoxide reductases. | free-living protozoa affect the survival and virulence evolution of pathogens in the environment. in this study, we explored the fate of aeromonas hydrophila when co-cultured with the bacteriovorous ciliate tetrahymena thermophila and investigated bacterial gene expression associated with the co-culture. virulent a. hydrophila strains were found to have ability to evade digestion in the vacuoles of this protozoan. in a. hydrophila, a total of 116 genes were identified as up-regulated following c ... | 2016 | 28083518 |
| a comparison of the crystal structures of eukaryotic and bacterial ssu ribosomal rnas reveals common structural features in the hypervariable regions. | while the majority of the ribosomal rna structure is conserved in the three major domains of life--archaea, bacteria, and eukaryotes, specific regions of the rrna structure are unique to at least one of these three primary forms of life. in particular, the comparative secondary structure for the eukaryotic ssu rrna contains several regions that are different from the analogous regions in the bacteria. our detailed analysis of two recently determined eukaryotic 40s ribosomal crystal structures, t ... | 2012 | 22693601 |
| the structure and function of the eukaryotic ribosome. | structures of the bacterial ribosome have provided a framework for understanding universal mechanisms of protein synthesis. however, the eukaryotic ribosome is much larger than it is in bacteria, and its activity is fundamentally different in many key ways. recent cryo-electron microscopy reconstructions and x-ray crystal structures of eukaryotic ribosomes and ribosomal subunits now provide an unprecedented opportunity to explore mechanisms of eukaryotic translation and its regulation in atomic ... | 2012 | 22550233 |
| structure of the 40s ribosomal subunit of plasmodium falciparum by homology and de novo modeling. | generation of three dimensional structures of macromolecules using in silico structural modeling technologies such as homology and de novo modeling has improved dramatically and increased the speed by which tertiary structures of organisms can be generated. this is especially the case if a homologous crystal structure is already available. high-resolution structures can be rapidly created using only their sequence information as input, a process that has the potential to increase the speed of sc ... | 2016 | 28119814 |
| application of a battery of biotests for the determination of leachate toxicity to bacteria and invertebrates from sewage sludge-amended soil. | the objective of the study was to determine the leachates toxicity from sewage sludge-amended soils (sandy and loamy). samples originated from a plot experiment realized over a period of 29 months. two types of soil were fertilized with sewage sludges at the dose of 3 % (90 t/ha). soil samples were taken after 0, 7, 17, and 29 months from the application of sewage sludges. leachates were obtained according to the en 12457-2 protocol. the following commercial tests were applied for the estimation ... | 2012 | 23132406 |
| environmental fluctuations restrict eco-evolutionary dynamics in predator-prey system. | environmental fluctuations, species interactions and rapid evolution are all predicted to affect community structure and their temporal dynamics. although the effects of the abiotic environment and prey evolution on ecological community dynamics have been studied separately, these factors can also have interactive effects. here we used bacteria-ciliate microcosm experiments to test for eco-evolutionary dynamics in fluctuating environments. specifically, we followed population dynamics and a prey ... | 2015 | 25994670 |
| protist predation can select for bacteria with lowered susceptibility to infection by lytic phages. | consumer-resource interactions constitute one of the most common types of interspecific antagonistic interaction. in natural communities, complex species interactions are likely to affect the outcomes of reciprocal co-evolution between consumers and their resource species. individuals face multiple enemies simultaneously, and consequently they need to adapt to several different types of enemy pressures. in this study, we assessed how protist predation affects the susceptibility of bacterial popu ... | 2015 | 25947228 |
| complete sequence of the mitochondrial genome of tetrahymena thermophila and comparative methods for identifying highly divergent genes. | the complete sequence of the mitochondrial genome of tetrahymena thermophila has been determined and compared with the mitochondrial genome of tetrahymena pyriformis. the sequence similarity clearly indicates homology of the entire t.thermophila and t.pyriformis mitochondrial genomes. the t.thermophila genome is very compact, most of the intergenic regions are short (only three are longer than 63 bp) and comprise only 3.8% of the genome. the nad9 gene is tandemly duplicated in t.thermophila. lon ... | 2003 | 12626709 |
| biotests and biosensors for ecotoxicology of metal oxide nanoparticles: a minireview. | nanotechnologies have become a significant priority worldwide. several manufactured nanoparticles - particles with one dimension less than 100 nm - are increasingly used in consumer products. at nanosize range, the properties of materials differ substantially from bulk materials of the same composition, mostly due to the increased specific surface area and reactivity, which may lead to increased bioavailability and toxicity. thus, for the assessment of sustainability of nanotechnologies, hazards ... | 2008 | 27873807 |
| whole genome sequencing identifies a novel factor required for secretory granule maturation in tetrahymena thermophila. | unbiased genetic approaches have a unique ability to identify novel genes associated with specific biological pathways. thanks to next generation sequencing, forward genetic strategies can be expanded to a wider range of model organisms. the formation of secretory granules, called mucocysts, in the ciliate tetrahymena thermophila relies, in part, on ancestral lysosomal sorting machinery, but is also likely to involve novel factors. in prior work, multiple strains with defects in mucocyst biogene ... | 2016 | 27317773 |
| entry and killing of tetrahymena thermophila by bacterially produced shiga toxin. | phage-encoded shiga toxin (stx) acts as a bacterial defense against the eukaryotic predator tetrahymena thermophila. it is unknown how stx enters tetrahymena protozoa or how it kills them. tetrahymena protozoa are phagocytotic; hence, stx could gain entry to the cytoplasm through the oral apparatus or via endocytosis. we find that stx2 can kill t. thermophila protozoa that lack an oral apparatus, indicating that stx2 can enter these cells via endocytosis. as opposed to the lack of effect on mamm ... | 2012 | 23269826 |
| coincidental loss of bacterial virulence in multi-enemy microbial communities. | the coincidental virulence evolution hypothesis suggests that outside-host selection, such as predation, parasitism and resource competition can indirectly affect the virulence of environmentally-growing bacterial pathogens. while there are some examples of coincidental environmental selection for virulence, it is also possible that the resource acquisition and enemy defence is selecting against it. to test these ideas we conducted an evolutionary experiment by exposing the opportunistic pathoge ... | 2014 | 25365586 |
| a parallel g quadruplex-binding protein regulates the boundaries of dna elimination events of tetrahymena thermophila. | guanine (g)-rich dna readily forms four-stranded quadruplexes in vitro, but evidence for their participation in genome regulation is limited. we have identified a quadruplex-binding protein, lia3, that controls the boundaries of germline-limited, internal eliminated sequences (iess) of tetrahymena thermophila. differentiation of this ciliate's somatic genome requires excision of thousands of iess, targeted for removal by small-rna-directed heterochromatin formation. in cells lacking lia3 (δlia3) ... | 2016 | 26950070 |
| mtnbd is a multifunctional fusion enzyme in the methionine salvage pathway of tetrahymena thermophila. | to recycle reduced sulfur to methionine in the methionine salvage pathway (msp), 5-methylthioribulose-1-phosphate is converted to 2-keto-4-methylthiobutyrate, the methionine precursor, by four steps; dehydratase, enolase, phosphatase, and dioxygenase reactions (catalyzed by mtnb, mtnw, mtnx and mtnd, respectively, in bacillus subtilis). it has been proposed that the mtnbd fusion enzyme in tetrahymena thermophila catalyzes four sequential reactions from the dehydratase to dioxygenase steps, based ... | 2013 | 23840871 |
| genome-wide identification and evolution of atp-binding cassette transporters in the ciliate tetrahymena thermophila: a case of functional divergence in a multigene family. | in eukaryotes, abc transporters that utilize the energy of atp hydrolysis to expel cellular substrates into the environment are responsible for most of the efflux from cells. many members of the superfamily of abc transporters have been linked with resistance to multiple drugs or toxins. owing to their medical and toxicological importance, members of the abc superfamily have been studied in several model organisms and warrant examination in newly sequenced genomes. | 2010 | 20977778 |
| gef1 is a ciliary sec7 gef of tetrahymena thermophila. | ciliary guanine nucleotide exchange factors (gefs) potentially activate g proteins in intraflagellar transport (ift) cargo release. several classes of gefs have been localized to cilia or basal bodies and shown to be functionally important in the prevention of ciliopathies, but ciliary arl-type sec 7 related gefs have not been well characterized. nair et al. [ 1999] identified a paramecium ciliary sec7 gef, psec7. in tetrahymena, gef1p (gef1), tentatively identified by psec7 antibody, possesses ... | 0 | 19267341 |
| microarray analyses of gene expression during the tetrahymena thermophila life cycle. | the model eukaryote, tetrahymena thermophila, is the first ciliated protozoan whose genome has been sequenced, enabling genome-wide analysis of gene expression. | 2009 | 19204800 |
| transcriptome analysis of the model protozoan, tetrahymena thermophila, using deep rna sequencing. | the ciliated protozoan tetrahymena thermophila is a well-studied single-celled eukaryote model organism for cellular and molecular biology. however, the lack of extensive t. thermophila cdna libraries or a large expressed sequence tag (est) database limited the quality of the original genome annotation. | 2012 | 22347391 |
| highly divergent mitochondrial atp synthase complexes in tetrahymena thermophila. | the f-type atp synthase complex is a rotary nano-motor driven by proton motive force to synthesize atp. its f(1) sector catalyzes atp synthesis, whereas the f(o) sector conducts the protons and provides a stator for the rotary action of the complex. components of both f(1) and f(o) sectors are highly conserved across prokaryotes and eukaryotes. therefore, it was a surprise that genes encoding the a and b subunits as well as other components of the f(o) sector were undetectable in the sequenced g ... | 2010 | 20644710 |
| top-down effects of a lytic bacteriophage and protozoa on bacteria in aqueous and biofilm phases. | lytic bacteriophages and protozoan predators are the major causes of bacterial mortality in natural microbial communities, which also makes them potential candidates for biological control of bacterial pathogens. however, little is known about the relative impact of bacteriophages and protozoa on the dynamics of bacterial biomass in aqueous and biofilm phases. here, we studied the temporal and spatial dynamics of bacterial biomass in a microcosm experiment where opportunistic pathogenic bacteria ... | 2014 | 25512841 |
| tetrahymena: an alternative model host for evaluating virulence of aeromonas strains. | an easier assessment model would be helpful for high-throughput screening of aeromonas virulence. the previous study indicated the potential of tetrahymena as a permissive model to examine virulence of aeromonas hydrophila. here our aim was to assess virulence of aeromonas spp. using two model hosts, a zebrafish assay and tetrahymena-aeromonas co-culture, and to examine whether data from the tetrahymena thermophila model reflects infections in the well-established animal model. first, virulence ... | 2012 | 23145022 |
| the relative importance of competition and predation in environment characterized by resource pulses--an experimental test with a microbial community. | resource availability and predation are believed to affect community dynamics and composition. although the effects of resource availability and predation on prey communities are usually studied in isolation, these factors can also have interactive effects, especially since the outcome of competition under shared predation is expected to depend on resource availability. however, there are few experimental studies that test the interactive roles of resources and predation on dynamics of more comp ... | 2013 | 24139511 |
| structure-function studies link class ii viral fusogens with the ancestral gamete fusion protein hap2. | the conserved transmembrane protein, hap2/gcs1, has been linked to fertility in a wide range of taxa and is hypothesized to be an ancient gamete fusogen. using template-based structural homology modeling, we now show that the ectodomain of hap2 orthologs from tetrahymena thermophila and other species adopt a protein fold remarkably similar to the dengue virus e glycoprotein and related class ii viral fusogens. to test the functional significance of this predicted structure, we developed a flow-c ... | 2017 | 28238660 |
| non-conventional expression systems for the production of vaccine proteins and immunotherapeutic molecules. | the increasing demand for recombinant vaccine antigens or immunotherapeutic molecules calls into question the universality of current protein expression systems. vaccine production can require relatively low amounts of expressed materials, but represents an extremely diverse category consisting of different target antigens with marked structural differences. in contrast, monoclonal antibodies, by definition share key molecular characteristics and require a production system capable of very large ... | 2016 | 27905833 |
| protozoal ciliate promotes bacterial autoinducer-2 accumulation in mixed culture with escherichia coli. | 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 formation, which controls quorum sensing. e. coli ai-2 accumulation was significantly enhanced in the supernata ... | 2015 | 26582290 |
| differentiation of a free-living alga into forms with ecto- and endosymbiotic associations with heterotrophic organisms in a 5-year microcosm culture. | the ecological mechanisms underlying the diversification of autotrophic species into endosymbiotic lifestyles and the ways in which the evolution of endosymbiotic species is ecologically and evolutionarily affected by sister lineages/lines that are adapted to extra-host environments remain unclear. in this paper, we investigated a differentiation process of algal species in which an endosymbiotic type was differentiated phenotypically from a free-living ancestral clone, by using an experimental ... | 2015 | 25816767 |
| cloning, expression and characterization of a gene encoding mitogen activated protein kinase 2 (mpk2) from tetrahymena thermophila. | environmental effects and mitogens determine cell phenotype in eukaryotes mainly through mapk pathways. however, mapk signaling pathways in t. thermophila have not been studied comprehensively. this study aims to express recombinant mpk2, a mapk from t. thermophila, in e. coli to characterize its kinase activity. mpk2 was cloned by rt-pcr using degenerate oligonucleotide primers and race method. the full-length cdna of the mpk2 gene is 1705bp that includes 1281bp orf coding for a putative protei ... | 2014 | 24858074 |
| trans-splicing with the group i intron ribozyme from azoarcus. | group i introns are ribozymes (catalytic rnas) that excise themselves from rna primary transcripts by catalyzing two successive transesterification reactions. these cis-splicing ribozymes can be converted into trans-splicing ribozymes, which can modify the sequence of a separate substrate rna, both in vitro and in vivo. previous work on trans-splicing ribozymes has mostly focused on the 16s rrna group i intron ribozyme from tetrahymena thermophila. here, we test the trans-splicing potential of t ... | 2014 | 24344321 |
| physiological changes of a green alga (micractinium sp.) involved in an early-stage of association with tetrahymena thermophila during 5-year microcosm culture. | endosymbioses between phototrophic algae and heterotrophic organisms are an important symbiotic association in that this association connects photo- and heterotrophic metabolism, and therefore, affects energy/matter pathways and cycling in the ecosystem. however, little is known about the early processes of evolution of an endosymbiotic association between previously non-associated organisms. in previous studies, we analyzed an early process of the evolution of an endosymbiotic association betwe ... | 2013 | 24035831 |
| exploitation or cooperation? evolution of a host (ciliate)-benefiting alga in a long-term experimental microcosm culture. | controversy persists as to whether the acquisition of beneficial metabolic functions via endosymbiosis can occur suddenly on an evolutionary time scale. in this study, an early stage of endosymbiotic associations, which evolved from previously unassociated auto (photo)- and heterotrophic unicellular organisms was analyzed using an experimental ecosystem model, called cet microcosm. this ecosystem model was composed of a green alga (micractinium sp.; formerly described as chlorella vulgaris), a b ... | 2013 | 23756173 |
| determining rna three-dimensional structures using low-resolution data. | knowing the 3-d structure of an rna is fundamental to understand its biological function. nowadays x-ray crystallography and nmr spectroscopy are systematically applied to newly discovered rnas. however, the application of these high-resolution techniques is not always possible, and thus scientists must turn to lower resolution alternatives. here, we introduce a pipeline to systematically generate atomic resolution 3-d structures that are consistent with low-resolution data sets. we compare and ... | 2012 | 22387042 |
| carbon nanotube compared with carbon black: effects on bacterial survival against grazing by ciliates and antimicrobial treatments. | the ingestion and digestion of escherichia coli by the ciliated protozoan, tetrahymena thermophila, was investigated after an initial exposure to either water-soluble single-walled carbon nanotubes (swnt) or to carbon black (cb). both swnt and cb were internalised and visible in food vacuoles of ciliates. when presented with e. coli expressing green-fluorescent protein (gfp), these ciliates internalised bacteria as well. however, ciliates that had first internalised swnt but not cb subsequently ... | 2013 | 22313189 |
| identification and metabolic characterization of the zea mays mitochondrial homolog of the escherichia coli groel protein. | we have characterized an abundant mitochondrial protein from zea mays and have shown it to be structurally and metabolically indistinguishable from a previously described tetrahymena thermophila and saccharomyces cerevisiae mitochondrial protein, referred to as hsp60, which is homologous to the groel protein of escherichia coli. this z. mays protein, which we also refer to as hsp60, was found to be antigenically quite distinct from the chloroplast rubisco-binding protein, another groel homolog. ... | 1989 | 24271194 |
| compensatory mutations demonstrate that p8 and p6 are rna secondary structure elements important for processing of a group i intron. | compensatory mutations have been constructed which demonstrate that p8 and p6, two of nine proposed base-pairing interactions characteristic of group i introns, exist within the folded structure of the tetrahymena thermophila rrna intervening sequence, and that these secondary structure elements are important for splicing in e. coli and self-splicing in vitro. two-base mutations in the 5' and 3' segments of p8 are predicted to disrupt p8 and a strong splicing-defective phenotype is observed in e ... | 1989 | 2915927 |
| fluctuating temperature leads to evolution of thermal generalism and preadaptation to novel environments. | environmental fluctuations can select for generalism, which is also hypothesized to increase organisms' ability to invade novel environments. here, we show that across a range of temperatures, opportunistic bacterial pathogen serratia marcescens that evolved in fluctuating temperature (daily variation between 24°c and 38°c, mean 31°c) outperforms the strains that evolved in constant temperature (31°c). the growth advantage was also evident in novel environments in the presence of parasitic virus ... | 2013 | 24094344 |
| separation of bacteria, protozoa and carbon nanotubes by density gradient centrifugation. | sustainable production and use of carbon nanotube (cnt)-enabled materials require efficient assessment of cnt environmental hazards, including the potential for cnt bioaccumulation and biomagnification in environmental receptors. microbes, as abundant organisms responsible for nutrient cycling in soil and water, are important ecological receptors for studying the effects of cnts. quantification of cnt association with microbial cells requires efficient separation of cnt-associated cells from ind ... | 2016 | 27917301 |
| bioaccumulation of multiwall carbon nanotubes in tetrahymena thermophila by direct feeding or trophic transfer. | consumer goods contain multiwall carbon nanotubes (mwcnts) that could be released during product life cycles into the environment, where their effects are uncertain. here, we assessed mwcnt bioaccumulation in the protozoan tetrahymena thermophila via trophic transfer from bacterial prey (pseudomonas aeruginosa) versus direct uptake from growth media. the experiments were conducted using (14)c-labeled mwcnt ((14)c-mwcnt) doses at or below 1 mg/l, which proved subtoxic since there were no adverse ... | 2016 | 27398725 |
| separation of bacteria, protozoa and carbon nanotubes by density gradient centrifugation. | sustainable production and use of carbon nanotube (cnt)-enabled materials require efficient assessment of cnt environmental hazards, including the potential for cnt bioaccumulation and biomagnification in environmental receptors. microbes, as abundant organisms responsible for nutrient cycling in soil and water, are important ecological receptors for studying the effects of cnts. quantification of cnt association with microbial cells requires efficient separation of cnt-associated cells from ind ... | 2016 | 28335309 |
| phages can constrain protist predation-driven attenuation of pseudomonas aeruginosa virulence in multienemy communities. | the coincidental theory of virulence predicts that bacterial pathogenicity could be a by-product of selection by natural enemies in environmental reservoirs. however, current results are ambiguous and the simultaneous impact of multiple ubiquitous enemies, protists and phages on virulence evolution has not been investigated previously. here we tested experimentally how tetrahymena thermophila protist predation and pnm phage parasitism (bacteria-specific virus) alone and together affect the evolu ... | 2014 | 24671085 |
| pseudomonas aeruginosa adaptation to lungs of cystic fibrosis patients leads to lowered resistance to phage and protist enemies. | pathogenic life styles can lead to highly specialized interactions with host species, potentially resulting in fitness trade-offs in other ecological contexts. here we studied how adaptation of the environmentally transmitted bacterial pathogen, pseudomonas aeruginosa, to cystic fibrosis (cf) patients affects its survival in the presence of natural phage (14/1, φkz, pnm and pt7) and protist (tetrahymena thermophila and acanthamoebae polyphaga) enemies. we found that most of the bacteria isolated ... | 2013 | 24069407 |
| rapid prey evolution can alter the structure of predator-prey communities. | although microevolution has been shown to play an important role in pairwise antagonistic species interactions, its importance in more complex communities has received little attention. here, we used two pseudomonas fluorescens prey bacterial strains (sbw25 and f113) and tetrahymena thermophila protist predator to study how rapid evolution affects the structuring of predator-prey communities. both bacterial strains coexisted in the absence of predation, and f113 was competitively excluded in the ... | 2014 | 24372926 |
| continuous ozonation treatment of ofloxacin: transformation products, water matrix effect and aquatic toxicity. | the continuous ozonation of the antibiotic ofloxacin (ofx) has been performed using a synthetic water matrix and in a sewage treatment plant (stp) effluent. the aim was to study the effect of the water matrix on the ozonation with particular emphasis on the aquatic toxicity of treated water. ofx was completely removed in both water matrices, although the amount of ozone consumed for its depletion was strongly matrix-dependent. the extent of mineralization was limited and a number of intermediate ... | 2015 | 25796038 |
| personal care product preservatives: risk assessment and mixture toxicities with an industrial wastewater. | the aquatic toxicity of eight preservatives frequently used in personal care products (pcps) (iodopropynyl butylcarbamate, bronopol, diazolidinyl urea, benzalkonium chloride, zinc pyrithione, propylparaben, triclosan and a mixture of methylchloroisothiazolinone and methylisothiazolinone) was assessed by means of two different approaches: a battery of bioassays composed of single species tests of bacteria (vibrio fischeri and pseudomonas putida) and protozoa (tetrahymena thermophila), and a whole ... | 2015 | 25585550 |
| sfr1, a tetrahymena thermophila sfi1 repeat protein, modulates the production of cortical row basal bodies. | basal bodies are essential microtubule-based structures that template, anchor, and orient cilia at the cell surface. cilia act primarily in the generation of directional fluid flow and sensory reception, both of which are utilized for a broad spectrum of cellular processes. although basal bodies contribute to vital cell functions, the molecular contributors of their assembly and maintenance are poorly understood. previous studies of the ciliate tetrahymena thermophila revealed important roles fo ... | 2017 | 27904881 |
| phosphorylation-dependent targeting of tetrahymena hp1 to condensed chromatin. | the evolutionarily conserved proteins related to heterochromatin protein 1 (hp1), originally described in drosophila, are well known for their roles in heterochromatin assembly and gene silencing. targeting of hp1 proteins to specific chromatin locales is mediated, at least in part, by the hp1 chromodomain, which binds to histone h3 methylated at lysine 9 that marks condensed regions of the genome. mechanisms that regulate hp1 targeting are emerging from studies with yeast and metazoans and poin ... | 2017 | 27579368 |
| cdk3, a conjugation-specific cyclin-dependent kinase, is essential for the initiation of meiosis in tetrahymena thermophila. | meiosis is an important process in sexual reproduction. meiosis initiation has been found to be highly diverse among species. in yeast, it has been established that cyclin-dependent kinases (cdks) and cyclins are essential components in the meiosis initiation pathway. in this study, we identified 4 cdks in the model ciliate, tetrahymena thermophila, and we found one of them, cdk3, which is specifically expressed during early conjugation, to be essential for meiosis initiation. cdk3 deletion led ... | 2016 | 27420775 |
| dna-guided establishment of nucleosome patterns within coding regions of a eukaryotic genome. | a conserved hallmark of eukaryotic chromatin architecture is the distinctive array of well-positioned nucleosomes downstream from transcription start sites (tss). recent studies indicate that trans-acting factors establish this stereotypical array. here, we present the first genome-wide in vitro and in vivo nucleosome maps for the ciliate tetrahymena thermophila. in contrast with previous studies in yeast, we find that the stereotypical nucleosome array is preserved in the in vitro reconstituted ... | 2015 | 26330564 |
| checkpoint activation of an unconventional dna replication program in tetrahymena. | the intra-s phase checkpoint kinase of metazoa and yeast, atr/mec1, protects chromosomes from dna damage and replication stress by phosphorylating subunits of the replicative helicase, mcm2-7. here we describe an unprecedented atr-dependent pathway in tetrahymena thermophila in which the essential pre-replicative complex proteins, orc1p, orc2p and mcm6p are degraded in hydroxyurea-treated s phase cells. chromosomes undergo global changes during hu-arrest, including phosphorylation of histone h2a ... | 2015 | 26218270 |
| different polyamine pathways from bacteria have replaced eukaryotic spermidine biosynthesis in ciliates tetrahymena thermophila and paramecium tetaurelia. | the polyamine spermidine is absolutely required for growth and cell proliferation in eukaryotes, due to its role in post-translational modification of essential translation elongation factor eif5a, mediated by deoxyhypusine synthase. we have found that free-living ciliates tetrahymena and paramecium lost the eukaryotic genes encoding spermidine biosynthesis: s-adenosylmethionine decarboxylase (adometdc) and spermidine synthase (spdsyn). in tetrahymena, they were replaced by a gene encoding a fus ... | 2015 | 25994085 |
| heavy metal whole-cell biosensors using eukaryotic microorganisms: an updated critical review. | this review analyzes the advantages and disadvantages of using eukaryotic microorganisms to design whole-cell biosensors (wcbs) for monitoring environmental heavy metal pollution in soil or aquatic habitats. basic considerations for designing a eukaryotic wcb are also shown. a comparative analysis of the promoter genes used to design wcbs is carried out, and the sensitivity and reproducibility of the main reporter genes used is also reviewed. three main eukaryotic taxonomic groups are considered ... | 2015 | 25750637 |
| developmental regulation of the tetrahymena thermophila origin recognition complex. | the tetrahymena thermophila dna replication machinery faces unique demands due to the compartmentalization of two functionally distinct nuclei within a single cytoplasm, and complex developmental program. here we present evidence for programmed changes in orc and mcm abundance that are not consistent with conventional models for dna replication. as a starting point, we show that orc dosage is critical during the vegetative cell cycle and development. a moderate reduction in orc1p induces genome ... | 2015 | 25569357 |
| direct single-stranded dna binding by teb1 mediates the recruitment of tetrahymena thermophila telomerase to telomeres. | the eukaryotic reverse transcriptase telomerase copies its internal rna template to synthesize telomeric dna repeats at chromosome ends in balance with sequence loss during cell proliferation. previous work has established several factors involved in telomerase recruitment to telomeres in yeast and mammalian cells; however, it remains unclear what determines the association of telomerase with telomeres in other organisms. here we investigate the cell cycle dependence of telomere binding by each ... | 2014 | 25225329 |
| off-target effects of the septin drug forchlorfenuron on nonplant eukaryotes. | the septins are a family of gtp-binding proteins that form cytoskeletal filaments. septins are highly conserved and evolutionarily ancient but are absent from land plants. the synthetic plant cytokinin forchlorfenuron (fcf) was shown previously to inhibit budding yeast cell division and induce ectopic septin structures (m. iwase, s. okada, t. oguchi, and a. toh-e, genes genet. syst. 79:199-206, 2004, http://dx.doi.org/10.1266/ggs.79.199). subsequent studies in a wide range of eukaryotes have con ... | 2014 | 25217460 |
| msh4 and msh5 function in sc-independent chiasma formation during the streamlined meiosis of tetrahymena. | zmm proteins have been defined in budding yeast as factors that are collectively involved in the formation of interfering crossovers (cos) and synaptonemal complexes (scs), and they are a hallmark of the predominant meiotic recombination pathway of most organisms. in addition to this so-called class i co pathway, a minority of crossovers are formed by a class ii pathway, which involves the mus81-mms4 endonuclease complex. this is the only co pathway in the sc-less meiosis of the fission yeast. z ... | 2014 | 25217051 |
| the bifunctional protein ttfarat from tetrahymena thermophila catalyzes the formation of both precursors required to initiate ether lipid biosynthesis. | the biosynthesis of ether lipids and wax esters requires as precursors fatty alcohols, which are synthesized by fatty acyl reductases (fars). the presence of ether glycerolipids as well as branched wax esters has been reported in several free-living ciliate protozoa. in the genome of tetrahymena thermophila, the only orf sharing similarities with fars is fused to an acyltransferase-like domain, whereas, in most other organisms, fars are monofunctional proteins of similar size and domain structur ... | 2014 | 24917677 |
| a microfluidic-enabled mechanical microcompressor for the immobilization of live single- and multi-cellular specimens. | a microcompressor is a precision mechanical device that flattens and immobilizes living cells and small organisms for optical microscopy, allowing enhanced visualization of sub-cellular structures and organelles. we have developed an easily fabricated device, which can be equipped with microfluidics, permitting the addition of media or chemicals during observation. this device can be used on both upright and inverted microscopes. the apparatus permits micrometer precision flattening for nondestr ... | 2014 | 24444078 |
| role of class iii phosphatidylinositol 3-kinase during programmed nuclear death of tetrahymena thermophila. | programmed nuclear death (pnd) in the ciliate protozoan tetrahymena thermophila is a novel type of autophagy that occurs during conjugation, in which only the parental somatic macronucleus is destined to die and is then eliminated from the progeny cytoplasm. other coexisting nuclei, however, such as new micro- and macronuclei are unaffected. pnd starts with condensation in the nucleus followed by apoptotic dna fragmentation, lysosomal acidification, and final resorption. because of the peculiari ... | 2014 | 24280724 |
| conserved asf1-importin β physical interaction in growth and sexual development in the ciliate tetrahymena thermophila. | how the eukaryotic cell specifies distinct chromatin domains is a central problem in molecular biology. the ciliate protozoan tetrahymena thermophila features a separation of structurally and functionally distinct germ-line and somatic chromatin into two distinct nuclei, the micronucleus (mic) and macronucleus (mac) respectively. to address questions about how distinct chromatin states are assembled in the mac and mic, we have initiated studies to define protein-protein interactions for t. therm ... | 2013 | 24120531 |
| survival and growth of tetrahymena thermophila in media that are conventionally used for piscine and mammalian cells. | the transfer of tetrahymena thermophila from normosmotic solutions (~20-80 mosm/kg h(2)o) to hyperosmotic solutions (> 290 mosm/kg h(2)o) was investigated. during the first 24 h of transfer from proteose peptone yeast extract (ppye) to either 10 mm hepes or ppye with added nacl to give ~300 mosm/kg h(2)o, most ciliates died in hepes but survived in ppye. supplementing hyperosmotic hepes or ppye with fetal bovine serum (fbs) enhanced survival. when ciliates were transferred from ppye to a basal m ... | 2014 | 24118275 |
| nucleophagy at a glance. | under certain circumstances, the removal of damaged or non-essential parts of the nucleus, or even an entire nucleus, is crucial in order to promote cell longevity and enable proper function. a selective form of autophagy, known as nucleophagy, can be used to accomplish the degradation of nucleus-derived material. in this cell science at a glance article and the accompanying poster, we summarize the similarities and differences between the divergent modes of nucleophagy that have been described ... | 2013 | 24013549 |
| monoclonal antibodies recognize gly-leu-phe-gly repeat of nucleoporin nup98 of tetrahymena, yeasts, and humans. | nucleoporin nup98, an essential component of the nuclear pore complex, has multifunctional roles in nuclear functions including transcriptional regulation and nucleocytoplasmic transport. these functions mostly depend on a gly-leu-phe-gly (glfg) sequence appearing repetitively in the n-terminal region of nup98. as the glfg sequence is well conserved among nup98s from a wide variety of species including humans, yeasts, and ciliates such as tetrahymena thermophila, a specific antibody that recogni ... | 2013 | 23607342 |
| cytochrome b₅ coexpression increases tetrahymena thermophila δ6 fatty acid desaturase activity in saccharomyces cerevisiae. | very-long-chain polyunsaturated fatty acids such as arachidonic, eicosapentaenoic, and docosahexaenoic acids, are important to the physiology of many microorganisms and metazoans and are vital to human development and health. the production of these and related fatty acids depends on δ6 desaturases, the final components of an electron transfer chain that introduces double bonds into 18-carbon fatty acid chains. when a δ6 desaturase identified from the ciliated protist tetrahymena thermophila was ... | 2013 | 23584993 |
| sfr13, a member of a large family of asymmetrically localized sfi1-repeat proteins, is important for basal body separation and stability in tetrahymena thermophila. | directed fluid flow, which is achieved by the coordinated beating of motile cilia, is required for processes as diverse as cellular swimming, developmental patterning and mucus clearance. cilia are nucleated, anchored and aligned at the plasma membrane by basal bodies, which are cylindrical microtubule-based structures with ninefold radial symmetry. in the unicellular ciliate tetrahymena thermophila, two centrin family members associated with the basal body are important for both basal body orga ... | 2013 | 23426847 |
| the cytochrome b5 dependent c-5(6) sterol desaturase des5a from the endoplasmic reticulum of tetrahymena thermophila complements ergosterol biosynthesis mutants in saccharomyces cerevisiae. | tetrahymena thermophila is a free-living ciliate with no exogenous sterol requirement. however, it can perform several modifications on externally added sterols including desaturation at c5(6), c7(8), and c22(23). sterol desaturases in tetrahymena are microsomal enzymes that require cyt b(5), cyt b(5) reductase, oxygen, and reduced nad(p)h for their activity, and some of the genes encoding these functions have recently been identified. the des5a gene encodes a c-5(6) sterol desaturase, as shown ... | 2012 | 22982564 |
| the nonhistone, n-terminal tail of an essential, chimeric h2a variant regulates mitotic h3-s10 dephosphorylation. | h2a.y is an essential, divergent tetrahymena thermophila histone variant. it has a long nonhistone n terminus that contains leucine-rich repeats (lrr) and an lrr cap domain with similarity to sds22p, a regulator of yeast protein phosphatase 1 (pp1) activity in the nucleus. in growing cells, h2a.y is incorporated into micronuclei only during s phase, which occurs immediately after micronuclear mitosis. depletion of h2a.y causes prolonged retention of mitosis-associated histone h3-s10 phosphorylat ... | 2012 | 22426537 |
| conjugation is necessary for a bacterial plasmid to survive under protozoan predation. | horizontal gene transfer by conjugative plasmids plays a critical role in the evolution of antibiotic resistance. interactions between bacteria and other organisms can affect the persistence and spread of conjugative plasmids. here we show that protozoan predation increased the persistence and spread of the antibiotic resistance plasmid rp4 in populations of the opportunist bacterial pathogen serratia marcescens. a conjugation-defective mutant plasmid was unable to survive under predation, sugge ... | 2016 | 26843557 |
| life history trade-offs and relaxed selection can decrease bacterial virulence in environmental reservoirs. | pathogen virulence is usually thought to evolve in reciprocal selection with the host. while this might be true for obligate pathogens, the life histories of opportunistic pathogens typically alternate between within-host and outside-host environments during the infection-transmission cycle. as a result, opportunistic pathogens are likely to experience conflicting selection pressures across different environments, and this could affect their virulence through life-history trait correlations. we ... | 2012 | 22937098 |
| developmental regulation of gene expression in tetrahymena. | the onset of gene expression in tetrahymena thermophila during macronuclear differentiation was investigated by assay of galactokinase in conjugating deoxygalactose-resistant heterokaryons. our results distinguish three successive states of galactokinase gene expression for cells developing a new macronucleus: stage 0, refractory to induction; stage 1, inducible by refeeding; and stage 2, induced. the refractory period ends at 12 to 13 hr after the onset of conjugation; this corresponds to the t ... | 1986 | 3732608 |
| rapid and sensitive assays for phagosomal acidification in paramecium and tetrahymena. | biochemical and cytochemical procedures were developed to measure the rate of phagosomal acidification for phagosomal ph ranging from 5 to 2.5. these assays were based on the ph-dependent inactivation with time of horseradish peroxidase (hrp) activity, a result attributable to the dissociation of this enzyme to a colorless protein and ferriprotoporphyrin in acidic solutions. when preincubated in buffers of varying ph, the rate of hrp inactivation followed a sigmoid curve, with the highest rate o ... | 1985 | 4043094 |
| chorein, the protein responsible for chorea-acanthocytosis, interacts with β-adducin and β-actin. | chorea-acanthocytosis (chac) is an autosomal, recessive hereditary disease characterized by striatal neurodegeneration and acanthocytosis, and caused by loss of function mutations in the vacuolar protein sorting 13 homolog a (vps13a) gene. vps13a encodes chorein whose physiological function at the molecular level is poorly understood. in this study, we show that chorein interacts with β-adducin and β-actin. we first compare protein expression in human erythrocyte membranes using proteomic analys ... | 2013 | 24129186 |
| pgbd5: a neural-specific intron-containing piggybac transposase domesticated over 500 million years ago and conserved from cephalochordates to humans. | piggybac domain (pgbd) transposons are found in organisms ranging from fungi to humans. three domesticated piggybac elements have been described. in the ciliates paramecium tetraurelia and tetrahymena thermophila, homologs known as piggymacs excise internal eliminated sequences from germline micronuclear dna during regeneration of the new somatic macronucleus. in primates, a pgbd3 element inserted into the cockayne syndrome group b (csb) gene over 43 mya serves as an alternative 3' terminal exon ... | 2013 | 24180413 |
| thymidine kinase from tetrahymena thermophila. purification and immunological analysis. | thymidine kinase is an enzyme involved in dna precursor metabolism and dna replication. the synthesis of this enzyme is highly regulated during the cell cycle and the activity of the enzyme is also regulated by feedback inhibition. genes encoding thymidine kinase have been extremely useful as selectable markers for introducing dna into a number of cells. in order to study cell cycle regulation of thymidine kinase, the gene which encodes this enzyme, as well as aspects of dna replication in the c ... | 1991 | 1991476 |
| an interlaboratory comparison of nanosilver characterisation and hazard identification: harmonising techniques for high quality data. | within the fp7 eu project nanovalid a consortium of six partners jointly investigated the hazard of silver nanoparticles (agnps) paying special attention to methodical aspects that are important for providing high-quality ecotoxicity data. laboratories were supplied with the same original stock dispersion of agnps. all partners applied a harmonised procedure for storage and preparation of toxicity test suspensions. altogether ten different toxicity assays with a range of environmentally relevant ... | 2016 | 26638016 |
| multigenerational effects of tris(1,3-dichloro-2-propyl) phosphate on the free-living ciliate protozoa tetrahymena thermophila exposed to environmentally relevant concentrations and after subsequent recovery. | tris(1,3-dichloro-2-propyl) phosphate (tdcipp) is considered a re-emerging environmental pollutant, and exposure to environmentally relevant concentrations has been shown to cause individual developmental toxicity in zebrafish and the water flea (daphnia magna). however, multigenerational effects during exposure to tdcipp and after subsequent recovery were unknown. in the present study, individuals of a model aquatic organism, the ciliated protozoan, t. thermophila were exposed to environmentall ... | 2016 | 27552037 |
| ecotoxicity evaluation of a wwtp effluent treated by solar photo-fenton at neutral ph in a raceway pond reactor. | some pollutants can be resistant to wastewater treatment, hence becoming a risk to aquatic and terrestrial biota even at the very low concentrations (ng l(-1)-μg l(-1)) they are commonly found at. tertiary treatments are used for micropollutant removal but little is known about the ecotoxicity of the treated effluent. in this study, a municipal secondary effluent was treated by a solar photo-fenton reactor at initial neutral ph in a raceway pond reactor, and ecotoxicity was evaluated before and ... | 2017 | 27335017 |
| application of simple and low-cost toxicity tests for ecotoxicological assessment of industrial wastewaters. | the objective of this study was to identify and to apply appropriate biotests having the advantages of being highly sensitive, easy to run, relatively inexpensive and able to substitute fish toxicity tests due to ethical reasons of animal welfare. to perform an ecotoxicological assessment of industrial wastewaters, different microbiotests were conducted to substitute the fish toxicity test with lebistes reticulatus through vibrio fischeri, thamnocephalus platyurus, daphnia magna, lemna minor and ... | 2015 | 25951939 |
| biochar properties regarding to contaminants content and ecotoxicological assessment. | the objective of the study was the determination of the content of contaminants and toxicity of four different biochars. the properties of the biochars, content of trace metals and polycyclic aromatic hydrocarbons (16 pahs) were determined. toxicological estimation of the biochars was performed on the basis of a battery of biotests with plants (lepidium sativum), bacteria (vibrio fischeri and 11 different strains from mara), alga (selenastrum capricornutum), protozoa (tetrahymena thermophila) an ... | 2013 | 23792930 |
| ecotoxicity of nanoparticles of cuo and zno in natural water. | the acute toxicity of cuo and zno nanoparticles in artificial freshwater (afw) and in natural waters to crustaceans daphnia magna and thamnocephalus platyurus and protozoan tetrahymena thermophila was compared. the l(e)c(50) values of nanocuo for both crustaceans in natural water ranged from 90 to 224 mg cu/l and were about 10-fold lower than l(e)c(50) values of bulk cuo. in all test media, the l(e)c(50) values for both bulk and nanozno (1.1-16 mg zn/l) were considerably lower than those of nano ... | 2010 | 19800155 |
| use of toxicity assays for enantiomeric discrimination of pharmaceutical substances. | toxicity assays are commonly used as general indicators of environmental water pollution. in the study described here, selected toxicity tests have been used to evaluate the different toxicity levels of enantiomers of different pharmaceutical drugs that can be found as potential contaminants in water environments. isomers of dopa, fluoxetine, and atenolol were tested with three aquatic organisms corresponding to different trophic levels: daphnia magna (a crustacean), pseudokirchneriella subcapit ... | 2009 | 18989896 |
| variability in secondary structure of 18s ribosomal rna as topological marker for identification of paramecium species. | besides cytological and molecular applications, paramecium is being used in water quality assessment and for determination of saprobic levels. an unambiguous identification of these unicellular eukaryotes is not only essential, but its ecological diversity must also be explored in the local environment. 18srrna genes of all the strains of paramecium species isolated from waste water were amplified, cloned and sequenced. phylogenetic comparison of the nucleotide sequences of these strains with 23 ... | 2014 | 25043709 |
| regions of variant histone his2avd required for drosophila development. | one way in which a distinct chromosomal domain could be established to carry out a specialized function is by the localized incorporation of specific histone variants into nucleosomes. h2az, one such variant of the histone protein h2a, is required for the survival of drosophila melanogaster, tetrahymena thermophila and mice (r. faast et al., in preparation). to search for the unique features of drosophila h2az (his2avd, also referred to as h2avd) that are required for its essential function, we ... | 1999 | 10385122 |
| the green tetrahymena utriculariae n. sp. (ciliophora, oligohymenophorea) with its endosymbiotic algae (micractinium sp.), living in traps of a carnivorous aquatic plant. | the genus tetrahymena (ciliophora, oligohymenophorea) probably represents the best studied ciliate genus. at present, more than forty species have been described. all are colorless, i.e. they do not harbor symbiotic algae, and as aerobes they need at least microaerobic habitats. here, we present the morphological and molecular description of the first green representative, tetrahymena utriculariae n. sp., living in symbiosis with endosymbiotic algae identified as micractinium sp. (chlorophyta). ... | 2016 | 27613221 |
| the effects of resource enrichment, dispersal, and predation on local and metacommunity structure. | community structure is the observable outcome of numerous processes. we conducted a laboratory experiment using a microbial model system to disentangle effects of nutrient enrichment, dispersal, and predation on prey species richness and predator abundance at local and metacommunity scales. prey species included: chilomonas sp., colpidium striatum, colpoda cucullus, paramecium tetraurelia, p. caudatum, philodina sp., spirostomum sp., tetrahymena thermophila, and uronema sp., and stentor coeruleu ... | 2006 | 16639564 |
| guanosine binds to the tetrahymena ribozyme in more than one step, and its 2'-oh and the nonbridging pro-sp phosphoryl oxygen at the cleavage site are required for productive docking. | the dynamics of binding of various guanosine, or g, substrates to the tetrahymena thermophila l-21 scai ribozyme have been investigated by fluorescence-detected stopped-flow experiments. upon rapid mixing of various g substrates with a preformed complex of the ribozyme and the fluorescent 5' splice site analogue ccucuepsilona, fluorescence transients that provide rates for binding of g substrates and the rate-limiting step for transesterification are observed. the measured apparent bimolecular r ... | 1997 | 9376352 |
| toxicity of nine (doped) rare earth metal oxides and respective individual metals to aquatic microorganisms vibrio fischeri and tetrahymena thermophila. | despite the increasing use of rare earth elements (rees) and oxides (reos) in various technologies, the information on their ecotoxicological hazard is scarce. here, the effects of la(3+), ce(3+), pr(3+), nd(3+), gd(3+), ceo₂, and eight doped reos to marine bacteria vibrio fischeri and freshwater protozoa tetrahymena thermophila were studied in parallel with reo dopant metals (co(2+), fe(3+), mn(2+), ni(2+), sr(2+)). the highest concentrations of reos tested were 100 mg/l with protozoa in deioni ... | 2017 | 28773114 |
| yeast and other lower eukaryotic organisms for studies of vps13 proteins in health and disease. | human vps13 proteins are associated with several diseases, including the neurodegenerative disorder chorea-acanthocytosis (chac), yet the biology of these proteins is still poorly understood. studies in saccharomyces cerevisiae, dictyostelium discoideum, tetrahymena thermophila and drosophila melanogaster point to the involvement of vps13 in cytoskeleton organization, vesicular trafficking, autophagy, phagocytosis, endocytosis, proteostasis, sporulation and mitochondrial functioning. recent find ... | 2017 | 28846184 |
| inhibition of the rumen ciliate entodinium caudatum by antibiotics. | axenic cultures of free-living aerobic ciliates, such as tetrahymena thermophila and paramecium aurelia, have been established and routinely used in laboratory research, greatly facilitating, or enabling characterization of their metabolism, physiology, and ecology. ruminal protozoa are anaerobic ciliates, and they play important roles in feed digestion and fermentation. although, repeatedly attempted, no laboratory-maintainable axenic culture of ruminal ciliates has been established. when axeni ... | 2017 | 28702015 |