| automated image analysis reveals the dynamic 3-dimensional organization of multi-ciliary arrays. | multi-ciliated cells (mccs) use polarized fields of undulating cilia (ciliary array) to produce fluid flow that is essential for many biological processes. cilia are positioned by microtubule scaffolds called basal bodies (bbs) that are arranged within a spatially complex 3-dimensional geometry (3d). here, we develop a robust and automated computational image analysis routine to quantify 3d bb organization in the ciliate, tetrahymena thermophila. using this routine, we generate the first morphol ... | 2015 | 26700722 |
| multicellular group formation in response to predators in the alga chlorella vulgaris. | a key step in the evolution of multicellular organisms is the formation of cooperative multicellular groups. it has been suggested that predation pressure may promote multicellular group formation in some algae and bacteria, with cells forming groups to lower their chance of being eaten. we use the green alga chlorella vulgaris and the protist tetrahymena thermophila to test whether predation pressure can initiate the formation of colonies. we found that: (1) either predators or just predator ex ... | 2016 | 26663204 |
| [acute toxicity and safety assessment of three typical organic pollutants to two aquatic organisms]. | acute toxic effects of three typical organic pollutants 1 ,2,4-trichlorobenzene (1,2,4-tcb), nitrobenzene and chlorpyrifos were investigated using tetrahymena thermophila and limnodrilus hoffmeisteri as living test organisms under laboratory conditions. the results showed that with the increase of pollutants' concentration and the extension of time, toxicity of the three kinds of pollutants significantly enhanced, and the mortality of two kinds of aquatic organisms also had a rising trend, and a ... | 2015 | 26592043 |
| <mds_ies_db>: a database of ciliate genome rearrangements. | ciliated protists exhibit nuclear dimorphism through the presence of somatic macronuclei (mac) and germline micronuclei (mic). in some ciliates, dna from precursor segments in the mic genome rearranges to form transcriptionally active genes in the mature mac genome, making these ciliates model organisms to study the process of somatic genome rearrangement. similar broad scale, somatic rearrangement events occur in many eukaryotic cells and tumors. the <mds_ies_db> (http://oxytricha.princeton.edu ... | 2016 | 26586804 |
| proteomic analyses of early response of unicellular eukaryotic microorganism tetrahymena thermophila exposed to tio₂ particles. | key biological functions involved in cell survival have been studied to understand the difference between the impact of exposure to tio2 nanoparticles (tio2-nps) and their bulk counterparts (bulk-tio2). by selecting a unicellular eukaryotic model organism and applying proteomic analysis an overview of the possible impact of exposure could be obtained. in this study, we investigated the early response of unicellular eukaryotic protozoan tetrahymena thermophila exposed to tio2-nps or bulk-tio2 par ... | 2016 | 26524663 |
| homology modeling procedures for cytoskeletal proteins of tetrahymena and other ciliated protists. | in recent years there has been an explosive increase in the number of annotated protein sequences available through genome sequencing, as well as an accumulation of published protein structural data based on crystallographic and nmr methods. when taken together with the development of computational methods for the prediction of protein structural and functional properties through homology modeling, an opportunity exists for prediction of properties of cytoskeletal proteins in a suitable model or ... | 2016 | 26498800 |
| using a handheld gene gun for genetic transformation of tetrahymena thermophila. | this chapter describes protocols for using a handheld gene gun to deliver transformation vectors for overexpression of genes or gene replacement in the macronucleus of tetrahymena thermophila. the protocols provide helpful information for preparing tetrahymena for biolistic bombardment, preparation of vector-coated microcarriers, and basic gene gun operating procedures. | 2016 | 26498798 |
| identification, modeling, and characterization studies of tetrahymena thermophila myosin ferm domains suggests a conserved core fold but functional differences. | myosins (myo) define a superfamily of motor proteins which facilitate movement along cytoskeletal actin filaments in an atp-dependent manner. to date, over 30 classes of myosin have been defined that vary in their roles and distribution across different taxa. the multidomain tail of myosin is responsible for the observed functional differences in different myosin classes facilitating differential binding to different cargos. one domain found in this region, the ferm domain, is found in several d ... | 2015 | 26492945 |
| correction: selecting one of several mating types through gene segment joining and deletion in tetrahymena thermophila. | | 2015 | 26488167 |
| signalling in ciliates: long- and short-range signals and molecular determinants for cellular dynamics. | in ciliates, unicellular representatives of the bikont branch of evolution, inter- and intracellular signalling pathways have been analysed mainly in paramecium tetraurelia, paramecium multimicronucleatum and tetrahymena thermophila and in part also in euplotes raikovi. electrophysiology of ciliary activity in paramecium spp. is a most successful example. established signalling mechanisms include plasmalemmal ion channels, recently established intracellular ca2+ -release channels, as well as sig ... | 2017 | 26487631 |
| the nuclear pore complex acts as a master switch for nuclear and cell differentiation. | cell differentiation is associated with the functional differentiation of the nucleus, in which alteration of the expression profiles of transcription factors occurs to destine cell fate. nuclear transport machineries, such as importin-α, have also been reported as critical factors that induce cell differentiation. using various fluorescence live cell imaging methods, including time-lapse imaging, frap analysis and live-cell imaging associated correlative light and electron microscopy (live clem ... | 2017 | 26479399 |
| depletion of ubc9 causes nuclear defects during the vegetative and sexual life cycles in tetrahymena thermophila. | ubc9p is the sole e2-conjugating enzyme for sumoylation, and its proper function is required for regulating key nuclear events such as transcription, dna repair, and mitosis. in tetrahymena thermophila, the genome is separated into a diploid germ line micronucleus (mic) that divides by mitosis and a polyploid somatic macronucleus (mac) that divides amitotically. this unusual nuclear organization provides novel opportunities for the study of sumoylation and ubc9p function. we identified the ubc9 ... | 2015 | 26453653 |
| high resistance of tetrahymena thermophila to paraquat: mitochondrial alterations, oxidative stress and antioxidant genes expression. | | 2016 | 26432532 |
| effects of triclosan and triclocarban on the growth inhibition, cell viability, genotoxicity and multixenobiotic resistance responses of tetrahymena thermophila. | the information about adverse effects of emerging contaminants on aquatic protozoa is very scarce. the growth inhibition effect, cell viability, genotoxicity and multixenobiotic resistance (mxr) responses of two commonly used antimicrobial agents, triclosan (tcs) and triclocarban (tcc) to protozoan tetrahymena thermophila were investigated in this study. the results revealed that tcs and tcc can inhibit the growth of t. thermophila with 24h ec50 values of 1063 and 295μgl(-1), respectively. the i ... | 2015 | 26246462 |
| secretion of polypeptide crystals from tetrahymena thermophila secretory organelles (mucocysts) depends on processing by a cysteine cathepsin, cth4p. | in many organisms, sophisticated mechanisms facilitate release of peptides in response to extracellular stimuli. in the ciliate tetrahymena thermophila, efficient peptide secretion depends on specialized vesicles called mucocysts that contain dense crystalline cores that expand rapidly during exocytosis. core assembly depends of endoproteolytic cleavage of mucocyst proproteins by an aspartyl protease, cathepsin 3 (cth3). here, we show that a second enzyme identified by expression profiling, cth4 ... | 2015 | 26092918 |
| effects of tris(1,3-dichloro-2-propyl) phosphate (tdcpp) in tetrahymena thermophila: targeting the ribosome. | tris(1,3-dichloro-2-propyl) phosphate (tdcpp) has been frequently detected in the environment, and exposure to tdcpp appears widespread. it has been implicated to cause toxicity in vertebrates, but its potential to affect lower-trophic-level species remains unknown. in the present study, the ciliated protozoan, tetrahymena thermophila, was used as a model to evaluate toxic effects of tdcpp and explore molecular mechanisms by integrating phenotypic observation, rna-seq and transmission electron m ... | 2015 | 25994279 |
| molecular polymorphism in the mta and mtb mating type genes of tetrahymena thermophila and related asexual species. | each of the seven mating types of tetrahymena thermophila is determined by a pair of large genes, mta and mtb, whose expression peaks at early conjugation. each protein consists of a mating-type specific domain and a common transmembrane domain. to assess variation in natural populations, regions of both domains from wild isolates expressing mating types v and vii were analyzed. corresponding regions of amicronucleates incapable of mating also were examined. mta and mtb showed high haplotype div ... | 2015 | 25973525 |
| social information from immigrants: multiple immigrant-based sources of information for dispersal decisions in a ciliate. | 1. dispersal is increasingly recognized as being an informed process, based on information organisms obtain about the landscape. while local conditions are often found to drive dispersal decisions, local context is not always a reliable predictor of conditions in neighbouring patches, making the use of local information potentially useless or even maladaptive. in this case, using social information gathered by immigrants might allow adjusting dispersal decisions without paying the costs of prosp ... | 2015 | 25902764 |
| efficient expression of codon-adapted affinity tagged super folder green fluorescent protein for synchronous protein localization and affinity purification studies in tetrahymena thermophila. | a superior green fluorescent protein (gfp) mutant, known as superfolder gfp (sfgfp), is more soluble, faster folding, and is the brightest of the known gfp mutants. this study aimed to create a codon-adapted sfgfp tag (ttsfgfp) for simultaneous protein localization and affinity purification in tetrahymena thermophila. | 2015 | 25887423 |
| identification of neutral and acidic deoxyribonuclease activities in tetrahymena thermophila life stages. | deoxyribonucleases (dnases) play a major role in apoptotic dna fragmentation/degradation, and apoptotic-like dna degradation is also observed during conjugation of the ciliate tetrahymena thermophila; however, the characteristics of neutral and acidic dnases are still undefined in its life stages. here, we report the biochemical characterization of dnase activities displayed in three different tetrahymena life stages in a comparative manner. maximum dnase activity of tetrahymena was observed und ... | 2015 | 25855143 |
| tetrahymena expresses more than a hundred proteins with lipid-binding morn motifs that can differ in their subcellular localisations. | proteins with membrane occupation and recognition nexus (morn) motifs are associated with cell fission in apicomplexan parasites, chloroplast division in arabidopsis and the motility of sperm cells. we found that ciliates are among those that encode the largest variety of morn proteins. tetrahymena thermophila expresses 129 morn protein-encoding genes, some of which are specifically up-regulated during conjugation. a lipid-binding assay underpins the assumption that the predominant function of m ... | 2015 | 25847055 |
| total internal reflection fluorescence microscopy of intraflagellar transport in tetrahymena thermophila. | live imaging has become a powerful tool in studies of ciliary proteins. tetrahymena thermophila is an established ciliated model with well-developed genetic and biochemical approaches, but its large size, complex shape, and the large number of short and overlapping cilia, have made live imaging of ciliary proteins challenging. here we describe a method that combines paralysis of cilia by nickel ions and total internal reflection microscopy for live imaging of fluorescent proteins inside cilia of ... | 2015 | 25837403 |
| the unique n-terminal insert in the ribosomal protein, phosphoprotein p0, of tetrahymena thermophila: bioinformatic evidence for an interaction with 26s rrna. | phosphoprotein p0 (p0) is part of the stalk complex of the eukaryotic large ribosomal subunit necessary for recruiting elongation factors. while the p0 sequence is highly conserved, our group noted a 15-16 residue insert exclusive to the p0s of ciliated protists, including tetrahymena thermophila. we hypothesized that this insert may have a function unique in ciliated protists, such as stalk regulation via phosphorylation of the insert. almost no mention of this insert exists in the literature, ... | 2015 | 25820769 |
| hints for metal-preference protein sequence determinants: different metal binding features of the five tetrahymena thermophila metallothioneins. | the metal binding preference of metallothioneins (mts) groups them in two extreme subsets, the zn/cd- and the cu-thioneins. ciliates harbor the largest mt gene/protein family reported so far, including 5 paralogs that exhibit relatively low sequence similarity, excepting mtt2 and mtt4. in tetrahymena thermophila, three mts (mtt1, mtt3 and mtt5) were considered cd-thioneins and two (mtt2 and mtt4) cu-thioneins, according to gene expression inducibility and phylogenetic analysis. in this study, th ... | 2015 | 25798065 |
| effect of melamine toxicity on tetrahymena thermophila proliferation and metallothionein expression. | melamine is a raw material in the chemical industry. because of its high nitrogen content, melamine has been utilized by unscrupulous businessmen as a food additive to enhance the indices of protein content in food and feed testing. tetrahymena has long been used as an excellent model organism in toxicological studies. the purpose of the present study was to determine the effect of melamine on tetrahymena. in the present study, the effects of melamine on the proliferation and mating rate of tetr ... | 2015 | 25720813 |
| cu,zn superoxide dismutases from tetrahymena thermophila: molecular evolution and gene expression of the first line of antioxidant defenses. | in the present study, we describe the molecular and functional characterization of two cu,zn superoxide dismutase (sod) genes, named tt-sod1a and tt-sod1b from tetrahymena thermophila, a free-living ciliated protozoan widely used as model organism in biological research. the cdnas and the putative amino acid sequences were compared with cu,zn sods from other alveolata. the primary sequences of t. thermophila cu,zn sods are unusually long if compared to orthologous proteins, but the catalytically ... | 2015 | 25681687 |
| expression and functional characterization of a c-7 cholesterol desaturase from tetrahymena thermophila in an insect cell line. | tetrahymena thermophila transforms exogenous cholesterol into pro-vitamin d3 (7-dehydrocholesterol) with remarkable efficiency in a one-step reaction carried out by a c-7 cholesterol desaturase. the enzyme des7 is encoded by the gene ttherm_00310640, identified with rnai and gene knock-out experiments, but has not yet been heterologously expressed actively in any organism. a model derived from its amino acid sequence classified des7p as a rieske-type oxygenase with transmembrane localization. th ... | 2015 | 25681633 |
| dynamic change of cellular localization of microtubule-organizing center during conjugation of ciliate tetrahymena thermophila. | to obtain a comprehensive picture of microtubule dynamics during conjugation, the mode of sexual reproduction in ciliates, we combined indirect immunofluorescence and three-dimensional imaging using confocal laser-scanning microscope to visualize the cellular localization of dna, microtubules, and γ-tubulin, the main component of the microtubule-organizing center in mating tetrahymena cells. as the conjugational stages proceeded, the distribution of γ-tubulin changed drastically and microtubules ... | 2015 | 25660693 |
| the microbiotest battery as an important component in the assessment of snowmelt toxicity in urban watercourses--preliminary studies. | the aim of the study was to use a battery of biotests composed of producers (selenastrum capricornutum, sorghum saccharatum, lepidium sativum, and sinapis alba), consumers (thamnocephalus platyurus), and decomposers (tetrahymena thermophila) to evaluate the toxicity of snowmelt and winter storm water samples. the toxicity of the samples collected in the winter period december to february (2010-2011), in one of the largest agglomerations in poland, the city of lodz, was compared to that of storm ... | 2015 | 25626567 |
| role of the cytosolic heat shock protein 70 ssa5 in the ciliate protozoan tetrahymena thermophila. | heat shock protein 70 (hsp70) is a member of a family of conserved chaperone proteins whose function is well investigated in many model organisms. here we focus on an hsp70 called ssa5 in the ciliate protozoan tetrahymena thermophila, and reveal that its translation is heat inducible as for general hsps. moreover, the protein is abundantly expressed in the cytoplasm during sexual reproduction (conjugation) as well as in response to heat-stress. knocking out of ssa5 (δssa5) does not affect the su ... | 2015 | 25586926 |
| potential genotoxicity and risk assessment of a chlorinated flame retardant, dechlorane plus. | dechlorane plus (dp) is a chlorinated flame retardants that is globally ubiquitous. it is a potentially persistent organic pollutant (pops) and an environmental toxin. however, the toxicity data is still limited and cannot provide a comprehensive environmental ecological risk assessment for dp. in this study, luminous bacteria, vicia faba and tetrahymena thermophila were chosen as testing organisms to investigate the acute toxicity and mutagenicity of dp. the concentration gradient of dp used in ... | 2015 | 25585867 |
| comparative cytotoxicity and accumulation of roxarsone and its photodegradates in freshwater protozoan tetrahymenathermophila. | roxarsone (rox) remains to be as an organoarsenical feed additive used widely in developing countries. however, most of the rox is excreted unchanged in manure, which could be readily photodegraded into inorganic arsenic derivatives. in this study, the comparative cytotoxicity and arsenic accumulation were evaluated after the exposure of tetrahymenathermophila (t. thermophila) cell model to rox and its photodegradates. the cytotoxic effects were estimated according to the relevant cell growth cu ... | 2015 | 25577319 |
| the toxicity of binary mixture of cu (ii) ion and phenols on tetrahymena thermophila. | the toxicity of binary mixture of cu(2+) and phenols (phenol; o-nitrophenol; m-nitrophenol; p-nitrophenol) was evaluated using tetrahymena thermophila as the model organism, by microcalorimetry, optical density, field emission scanning electron microscope (fesem) and attenuated total reflection-fourier transform infrared spectroscopy (atr-ftir). the growth curves and metabolic properties of tetrahymena exposed to cu(2+) and phenols were monitored by microcalorimetry. binary mixture toxicity chan ... | 2015 | 25540853 |
| disap-dependent striated fiber elongation is required to organize ciliary arrays. | cilia-organizing basal bodies (bbs) are microtubule scaffolds that are visibly asymmetrical because they have attached auxiliary structures, such as striated fibers. in multiciliated cells, bb orientation aligns to ensure coherent ciliary beating, but the mechanisms that maintain bb orientation are unclear. for the first time in tetrahymena thermophila, we use comparative whole-genome sequencing to identify the mutation in the bb disorientation mutant disa-1. disa-1 abolishes the localization of ... | 2014 | 25533842 |
| sumoylation is developmentally regulated and required for cell pairing during conjugation in tetrahymena thermophila. | the covalent attachment of small ubiquitin-like modifier (sumo) to target proteins regulates numerous nuclear events in eukaryotes, including transcription, mitosis and meiosis, and dna repair. despite extensive interest in nuclear pathways within the field of ciliate molecular biology, there have been no investigations of the sumo pathway in tetrahymena. the developmental program of sexual reproduction of this organism includes cell pairing, micronuclear meiosis, and the formation of a new soma ... | 2015 | 25527524 |
| in silico identification and characterization of the mapk family members of unicellular model eukaryote tetrahymena thermophila. | the biological function and evolutionary diversity of the mitogen-activated protein kinase (mapk) family have mostly been studied in fungi, animals and plants, with very limited information from lower eukaryotes. this study aimed to describe the mapks of unicellular tetrahymena thermophila. eight members of the t. thermophila mapk (ttmpk) gene family, in addition to previously reported ttmpk1, ttmpk2 and ttmpk3, were identified bioinformatically using a t. thermophila genome database. phylogenet ... | 2014 | 25286252 |
| [toxicity of three chlorophenols to protozoa tetrahymena thermophila]. | using tetrahymena thermophila as the indication organism, the single acute toxicity and genotoxicity induced by 2,4-dichlorophenol (2,4-dcp), 2,4,6-trichlorophenol (2,4,6-tcp) and pentachlorophenol (pcp) were determined. the results showed that the 24, 48, 72 and 96-hour ec50 values of 3 individual cps to t. thermophila were 3.69, 3.54, 3.02, 2.34 mg x l(-1); 3.23, 2.83, 2.56, 1.97 mg x l(-1) and 0.63, 0.45, 0.34, 0.28 mg x l(-1), respectively, which revealed that the acute toxicity of cps incre ... | 2014 | 25244865 |
| mutational robustness of morphological traits in the ciliate tetrahymena thermophila. | ciliate nuclear architecture, in particular the sequestration of a transcriptionally silent germline genome, allows for the accumulation of mutations that are "hidden" from selection during many rounds of asexual reproduction. after sexual conjugation, these mutations are expressed, potentially resulting in highly variable phenotypes. morphological traits are widely used in ciliate taxonomy, however, the extent to which the values of these traits are robust to change in the face of mutation rema ... | 2017 | 25227613 |
| methylation of histone h3k23 blocks dna damage in pericentric heterochromatin during meiosis. | despite the well-established role of heterochromatin in protecting chromosomal integrity during meiosis and mitosis, the contribution and extent of heterochromatic histone posttranslational modifications (ptms) remain poorly defined. here, we gained novel functional insight about heterochromatic ptms by analyzing histone h3 purified from the heterochromatic germline micronucleus of the model organism tetrahymena thermophila. mass spectrometric sequencing of micronuclear h3 identified h3k23 trime ... | 2014 | 25161194 |
| function of the male-gamete-specific fusion protein hap2 in a seven-sexed ciliate. | hap2, a male-gamete-specific protein conserved across vast evolutionary distances, has garnered considerable attention as a potential membrane fusogen required for fertilization in taxa ranging from protozoa and green algae to flowering plants and invertebrate animals [1-6]. however, its presence in tetrahymena thermophila, a ciliated protozoan with seven sexes or mating types that bypasses the production of male gametes, raises interesting questions regarding the evolutionary origins of gamete- ... | 2014 | 25155508 |
| genome-wide prediction of the polymorphic ser gene family in tetrahymena thermophila based on motif analysis. | even though antigenic variation is employed among parasitic protozoa for host immune evasion, tetrahymena thermophila, a free-living ciliate, can also change its surface protein antigens. these cysteine-rich glycosylphosphatidylinositol (gpi)-linked surface proteins are encoded by a family of polymorphic ser genes. despite the availability of t. thermophila genome, a comprehensive analysis of the ser family is limited by its high degree of polymorphism. in order to overcome this problem, a new a ... | 2014 | 25133747 |
| membrane dynamics at the nuclear exchange junction during early mating (one to four hours) in the ciliate tetrahymena thermophila. | using serial-section transmission electron microscopy and three-dimensional (3d) electron tomography, we characterized membrane dynamics that accompany the construction of a nuclear exchange junction between mating cells in the ciliate tetrahymena thermophila. our methods revealed a number of previously unknown features. (i) membrane fusion is initiated by the extension of hundreds of 50-nm-diameter protrusions from the plasma membrane. these protrusions extend from both mating cells across the ... | 2015 | 25107923 |
| lia4 encodes a chromoshadow domain protein required for genomewide dna rearrangements in tetrahymena thermophila. | extensive dna elimination occurs as part of macronuclear differentiation during tetrahymena sexual reproduction. the identification of sequences to excise is guided by a specialized rna interference (rnai) machinery that targets the methylation of histone h3 lysine 9 (k9) and k27 on chromatin associated with these internal eliminated sequences (iess). this modified chromatin is reorganized into heterochromatic subnuclear foci, which is a hallmark of their subsequent elimination. here, we demonst ... | 2014 | 25084866 |
| potential of hyperspectral imaging microscopy for semi-quantitative analysis of nanoparticle uptake by protozoa. | hyperspectral imaging with enhanced darkfield microscopy (hsi-m) possesses unique advantages in its simplicity and non-invasiveness. in consideration of the urgent need for profound knowledge on the behavior and effects of engineered nanoparticles (nps), here, we determined the capability of hsi-m for examining cellular uptake of different metal-based nps, including nanosized metals (silver and gold, both citrate stabilized), metal oxides (copper oxide and titanium dioxide), and cdse/zns core/sh ... | 2014 | 25000358 |
| an aspartyl cathepsin, cth3, is essential for proprotein processing during secretory granule maturation in tetrahymena thermophila. | in tetrahymena thermophila, peptides secreted via dense-core granules, called mucocysts, are generated by proprotein processing. we used expression profiling to identify candidate processing enzymes, which localized as cyan fluorescent protein fusions to mucocysts. of note, the aspartyl cathepsin cth3p plays a key role in mucocyst-based secretion, since knockdown of this gene blocked proteolytic maturation of the entire set of mucocyst proproteins and dramatically reduced mucocyst accumulation. ... | 2014 | 24943840 |
| tio2 nanoparticles act as a carrier of cd bioaccumulation in the ciliate tetrahymena thermophila. | when nanoparticles can enter a unicellular organism directly, how may they affect the bioaccumulation and toxicity of other pollutants already present in the environment? to answer this question, we conducted experiments with a protozoan tetrahymena thermophila. the well-dispersed polyacrylate-coated tio2 nanoparticles (paa-tio2-nps) were used as a representative nanomaterial, and cd as a conventional pollutant. we found that paa-tio2-nps could get into tetrahymena cells directly. such internali ... | 2014 | 24912115 |
| abandoning sex: multiple origins of asexuality in the ciliate tetrahymena. | by segregating somatic and germinal functions into large, compound macronuclei and small diploid micronuclei, respectively, ciliates can explore sexuality in ways other eukaryotes cannot. sex, for instance, is not for reproduction but for nuclear replacement in the two cells temporarily joined in conjugation. with equal contributions from both conjugants, there is no cost of sex which theory predicts should favor asexuality. yet ciliate asexuality is rare. the exceptional tetrahymena has abandon ... | 2014 | 24885485 |
| delineating cellular interactions between ciliates and fish by co-culturing tetrahymena thermophila with fish cells. | although several species of tetrahymena are often described as histophagous and opportunistic pathogens of fish, little is known about ciliate/fish cell interactions, but one approach for studying these is in vitro with cell lines. in this study, t. thermophila, b1975 (wild type) and np1 (temperature sensitive mutant for phagocytosis) were cultured on monolayers of 3 fish epithelial cell lines, chse-214, rtgill-w1, and zeb2j, and the rabbit kidney epithelial cell line, rk-13. generally the cilia ... | 2014 | 24801100 |
| conservation of major and minor jelly-roll capsid proteins in polinton (maverick) transposons suggests that they are bona fide viruses. | polintons (also known as mavericks) and tlr elements of tetrahymena thermophila represent two families of large dna transposons widespread in eukaryotes. here, we show that both polintons and tlr elements encode two key virion proteins, the major capsid protein with the double jelly-roll fold and the minor capsid protein, known as the penton, with the single jelly-roll topology. this observation along with the previously noted conservation of the genes for viral genome packaging atpase and adeno ... | 2014 | 24773695 |
| dispersal propensity in tetrahymena thermophila ciliates - a reaction norm perspective. | dispersal and phenotypic plasticity are two main ways for species to deal with rapid changes of their environments. understanding how genotypes (g), environments (e), and their interaction (genotype and environment; g × e) each affects dispersal propensity is therefore instrumental for predicting the ecological and evolutionary responses of species under global change. here we used an actively dispersing ciliate to quantify the contributions of g, e, and g × e on dispersal propensity, exposing 4 ... | 2014 | 24749831 |
| uptake, localization and clearance of quantum dots in ciliated protozoa tetrahymena thermophila. | protozoa as phagocytizing cells have been shown to integrate engineered nanoparticles (nps), while the mechanism, dynamics and extent of such uptake are unclear. here our fluorescence microscopy data showed that cdse/zns quantum dots (qds) with primary size of 12 nm were readily phagocytized into the food vacuoles of tetrahymena thermophila in a time- and dose-dependent manner. twenty hours after the exposure to qds in sublethal concentration the clearance of the qds from the cells was incomplet ... | 2014 | 24727587 |
| tetrahymena thermophila: a divergent perspective on membrane traffic. | tetrahymena thermophila, a member of the ciliates, represents a class of organisms distantly related from commonly used model organisms in cell biology, and thus offers an opportunity to explore potentially novel mechanisms and their evolution. ciliates, like all eukaryotes, possess a complex network of organelles that facilitate both macromolecular uptake and secretion. the underlying endocytic and exocytic pathways are key mediators of a cell's interaction with its environment, and may therefo ... | 2014 | 24634411 |
| a p450 gene associated with robust resistance to ddt in ciliated protozoan, tetrahymena thermophila by efficient degradation. | analysis of metabolic mechanisms of dichlorodiphenyltrichloroethane (ddt) accumulation and degradation in microorganisms, which could be used to reduce its hazard to higher organisms at the higher in the food chain, have not been investigated. robust resistance to ddt (grows well in 256 mg/l ddt) and a surprising ability to degrade ddt (more than 70% ddt within 4h) were found in the ciliated protozoan tetrahymena thermophila. a p450 gene (cyp5013c2) was found to respond specifically to ddt treat ... | 2014 | 24607688 |
| immediate dissemination of student discoveries to a model organism database enhances classroom-based research experiences. | use of inquiry-based research modules in the classroom has soared over recent years, largely in response to national calls for teaching that provides experience with scientific processes and methodologies. to increase the visibility of in-class studies among interested researchers and to strengthen their impact on student learning, we have extended the typical model of inquiry-based labs to include a means for targeted dissemination of student-generated discoveries. this initiative required: 1) ... | 2014 | 24591511 |
| mapping the kinetic barriers of a large rna molecule's folding landscape. | the folding of linear polymers into discrete three-dimensional structures is often required for biological function. the formation of long-lived intermediates is a hallmark of the folding of large rna molecules due to the ruggedness of their energy landscapes. the precise thermodynamic nature of the barriers (whether enthalpic or entropic) that leads to intermediate formation is still poorly characterized in large structured rna molecules. a classic approach to analyzing kinetic barriers are tem ... | 2014 | 24586236 |
| progress in structural studies of telomerase. | telomerase is the ribonucleoprotein (rnp) reverse transcriptase responsible for synthesizing the 3' ends of linear chromosomes. it plays critical roles in tumorigenesis, cellular aging, and stem cell renewal. the past two years have seen exciting progress in determining telomerase holoenzyme architecture and the structural basis of telomerase activity. notably, the first electron microscopy structures of telomerase were reported, of the tetrahymena thermophila telomerase holoenzyme and a human t ... | 2014 | 24508601 |
| a novel malaria vaccine candidate antigen expressed in tetrahymena thermophila. | development of effective malaria vaccines is hampered by the problem of producing correctly folded plasmodium proteins for use as vaccine components. we have investigated the use of a novel ciliate expression system, tetrahymena thermophila, as a p. falciparum vaccine antigen platform. a synthetic vaccine antigen composed of n-terminal and c-terminal regions of merozoite surface protein-1 (msp-1) was expressed in tetrahymena thermophila. the recombinant antigen was secreted into the culture medi ... | 2014 | 24489871 |
| functional gfp-metallothionein fusion protein from tetrahymena thermophila: a potential whole-cell biosensor for monitoring heavy metal pollution and a cell model to study metallothionein overproduction effects. | the significance of metal(oid)s as environmental pollutants has made them a priority in ecotoxicology, with the aim of minimizing exposure to animals or humans. therefore, it is necessary to develop sensitive and inexpensive methods that can efficiently detect and monitor these pollutants in the environment. conventional analytical techniques suffer from the disadvantages of high cost and complexity. alternatively, prokaryotic or eukaryotic whole-cell biosensors (wcb) are one of the newest molec ... | 2014 | 24430977 |
| a novel mitochondrial nuclease-associated protein: a major executor of the programmed nuclear death in tetrahymena thermophila. | programmed nuclear death (pnd) in the ciliate tetrahymena is an apoptosis-like phenomenon that occurs in a restricted space of cytoplasm during conjugation. in the process, only the parental macronucleus is selectively eliminated from the progeny cytoplasm, in conjunction with differentiation of new macronuclei for the next generation. for the last decade, mitochondria have been elucidated to be a crucial executioner like apoptosis: apoptosis-inducing factor and yet-unidentified nucleases locali ... | 2014 | 24392831 |
| quantitative proteomics reveals histone modifications in crosstalk with h3 lysine 27 methylation. | methylation at histone h3 lysine 27 (h3k27me) is an evolutionarily conserved epigenetic mark associated with transcriptional repression and replication elongation. we have previously shown that in tetrahymena thermophila, a unicellular eukaryote, the histone methyltransferases (hmts) txr1 and ezl2 are primarily responsible for h3k27 mono-methylation (h3k27me1) and di-/tri-methylation (h3k27me2/3), respectively. using (15)n metabolically labeled histones as the internal reference, we quantified g ... | 2014 | 24382802 |
| mutations in pdd1 reveal distinct requirements for its chromodomain and chromoshadow domain in directing histone methylation and heterochromatin elimination. | pdd1, a specialized hp1-like protein, is required for genome-wide dna rearrangements that restructure a previously silent germ line genome into an active somatic genome during macronuclear differentiation of tetrahymena thermophila. we deleted or otherwise mutated conserved regions of the protein to investigate how its different domains promote the excision of thousands of internal eliminated sequences (iess). previous studies revealed that pdd1 contributes to recognition of ies loci after they ... | 2014 | 24297443 |
| the 3' overhangs at tetrahymena thermophila telomeres are packaged by four proteins, pot1a, tpt1, pat1, and pat2. | although studies with the ciliate tetrahymena thermophila have played a central role in advancing our understanding of telomere biology and telomerase mechanisms and composition, the full complement of tetrahymena telomere proteins has not yet been identified. previously, we demonstrated that in tetrahymena, the telomeric 3' overhang is protected by a three-protein complex composed of pot1a, tpt1, and pat1. here we show that tpt1 and pat1 associate with a fourth protein, pat2 (pot1 associated te ... | 2014 | 24297442 |
| identification of dopamine receptor in tetrahymena thermophila by fluorescent ligands. | two types dopamine receptor present in the cell membrane of vertebrates. but in this study d1 receptor was identified in the invertebrate ciliates protozoan, tetrahymena thermophila by use of fluorescent ligands. d1 specific agonist skf-38393 binds specifically to tetrahymena. the specific binding of skf-38393 was encountered by equimolar addition of d1 antagonist thus showed no binding of ligands. in addition, it was also proved that the d1 specific agonist did not cross bind with the d2 type r ... | 2012 | 24261116 |
| genome-wide analysis of the phosphoinositide kinome from two ciliates reveals novel evolutionary links for phosphoinositide kinases in eukaryotic cells. | the complexity of phosphoinositide signaling in higher eukaryotes is partly due to expansion of specific families and types of phosphoinositide kinases (piks) that can generate all phosphoinositides via multiple routes. this is particularly evident in the pi3ks and pipks, and it is considered an evolutionary trait associated with metazoan diversification. yet, there are limited comprehensive studies on the pik repertoire of free living unicellular organisms. | 2013 | 24244373 |
| phosphoproteomic analysis of protein phosphorylation networks in tetrahymena thermophila, a model single-celled organism. | tetrahymena thermophila is a widely used unicellular eukaryotic model organism in biological research and contains more than 1000 protein kinases and phosphatases with specificity for ser/thr/tyr residues. however, only a few dozen phosphorylation sites in t. thermophila are known, presenting a major obstacle to further understanding of the regulatory roles of reversible phosphorylation in this organism. in this study, we used high-accuracy mass-spectrometry-based proteomics to conduct global an ... | 2014 | 24200585 |
| genetic background alters dominance relationships between mat alleles in the ciliate tetrahymena thermophila. | the pattern of inheritance and mechanism of sex determination can have important evolutionary consequences. we studied probabilistic sex determination in the ciliate tetrahymena thermophila, which was previously shown to cause evolution of skewed sex ratios. we find that the genetic background alters the sex determination patterns of mat alleles in heterozygotes and that allelic interaction can differentially influence the expression probability of the 7 sexes. we quantify the dominance relation ... | 2013 | 24190504 |
| lysosomal sorting receptors are essential for secretory granule biogenesis in tetrahymena. | secretory granules, such as neuronal dense core vesicles, are specialized for storing cargo at high concentration and releasing it via regulated exocytosis in response to extracellular stimuli. here, we used expression profiling to identify new components of the machinery for sorting proteins into mucocysts, secretory granule-like vesicles in the ciliate tetrahymena thermophila. we show that assembly of mucocysts depends on proteins classically associated with lysosome biogenesis. in particular, ... | 2013 | 24189272 |
| puromycin resistance gene as an effective selection marker for ciliate tetrahymena. | a puromycin-n-acetyltransferase gene (pac) is widely used as a selection marker for eukaryotic gene manipulation. however, it has never been utilized for molecular studies in the ciliate tetrahymena thermophila, in spite of the limited number of selection markers available for this organism. to utilize pac as a maker gene for t. thermophila, the nucleotide sequence of the pac gene was altered to accord with the most preferred codon-usage in t. thermophila. this codon-optimized pac gene expressed ... | 2014 | 24185080 |
| effects of four commonly used uv filters on the growth, cell viability and oxidative stress responses of the tetrahymena thermophila. | uv filters are increasingly used in sunscreens and other personal care products. although their residues have been widely identified in aquatic environment, little is known about the influences of uv filters to protozoan. the growth inhibition effects, cell viability and oxidative stress responses of four commonly used uv filters, 2-ethylhexyl 4-methoxycinnamate (ehmc), benzophenone-3 (bp-3), 4-methyl-benzylidene camphor (4-mbc) and octocrylene (oc), to protozoan tetrahymena thermophila were inv ... | 2013 | 24129001 |
| lia5 is required for nuclear reorganization and programmed dna rearrangements occurring during tetrahymena macronuclear differentiation. | during macronuclear differentiation of the ciliate tetrahymena thermophila, genome-wide dna rearrangements eliminate nearly 50 mbp of germline derived dna, creating a streamlined somatic genome. the transposon-like and other repetitive sequences to be eliminated are identified using a pirna pathway and packaged as heterochromatin prior to their removal. in this study, we show that lia5, which encodes a zinc-finger protein likely of transposon origin, is required for both chromosome fragmentation ... | 2013 | 24069402 |
| a motif in the vertebrate telomerase n-terminal linker of tert contributes to rna binding and telomerase activity and processivity. | telomerase is a ribonucleoprotein reverse transcriptase that replicates the ends of chromosomes, thus maintaining genome stability. telomerase ribonucleoprotein assembly is primarily mediated by the rna binding domain (trbd) of the enzyme. here we present the high-resolution trbd structure of the vertebrate, takifugu rubripes (trtrbd). the structure shows that with the exception of the n-terminal linker, the trtrbd is conserved with the tribolium castaneum and tetrahymena thermophila trbds, sugg ... | 2013 | 24055314 |
| transposon domestication versus mutualism in ciliate genome rearrangements. | 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 dde/ddd superfamily are indispensible for dna processing in three distantly related ciliates. in the spir ... | 2013 | 23935529 |
| accumulation of spontaneous mutations in the ciliate tetrahymena thermophila. | knowledge of the rate and fitness effects of mutations is essential for understanding the process of evolution. mutations are inherently difficult to study because they are rare and are frequently eliminated by natural selection. in the ciliate tetrahymena thermophila, mutations can accumulate in the germline genome without being exposed to selection. we have conducted a mutation accumulation (ma) experiment in this species. assuming that all mutations are deleterious and have the same effect, w ... | 2013 | 23934880 |
| impaired replication elongation in tetrahymena mutants deficient in histone h3 lys 27 monomethylation. | replication of nuclear dna occurs in the context of chromatin and is influenced by histone modifications. in the ciliate tetrahymena thermophila, we identified txr1, encoding a histone methyltransferase. txr1 deletion resulted in severe dna replication stress, manifested by the accumulation of ssdna, production of aberrant replication intermediates, and activation of robust dna damage responses. paired-end illumina sequencing of ssdna revealed intergenic regions, including replication origins, a ... | 2013 | 23884606 |
| the crystal structure of the eukaryotic 40s ribosomal subunit in complex with eif1 and eif1a. | eukaryotic translation initiation factors (eifs) 1a and 1 are central players in the complex process of start-codon recognition. to improve mechanistic understanding of this process, we determined the crystal structure of the 40s ribosomal subunit in complex with eif1a and eif1 from tetrahymena thermophila at a resolution of 3.7 å. it reveals the positions of the two factors on the 40s and the conformational changes that accompany their binding. | 2013 | 23851459 |
| a conserved motif in tetrahymena thermophila telomerase reverse transcriptase is proximal to the rna template and is essential for boundary definition. | the ends of linear chromosomes are extended by telomerase, a ribonucleoprotein complex minimally consisting of a protein subunit called telomerase reverse transcriptase (tert) and the telomerase rna (ter). tert functions by reverse transcribing a short template region of ter into telomeric dna. proper assembly of tert and ter is essential for telomerase activity; however, a detailed understanding of how tert interacts with ter is lacking. previous studies have identified an rna binding domain (r ... | 2013 | 23760279 |
| nociceptin signaling involves a calcium-based depolarization in tetrahymena thermophila. | tetrahymena thermophila are free-living, ciliated eukaryotes. their behavioral response to stimuli is well characterized and easily observable, since cells swim toward chemoattractants and avoid chemorepellents. chemoattractant responses involve increased swim speed or a decreased change in swim direction, while chemorepellent signaling involves ciliary reversal, which causes the organism to jerk back and forth, swim in small circles, or spin in an attempt to get away from the repellent. many fo ... | 2013 | 23737806 |
| adf/cofilin is not essential but is critically important for actin activities during phagocytosis in tetrahymena thermophila. | adf/cofilin is a highly conserved actin-modulating protein. reorganization of the actin cytoskeleton in vivo through severing and depolymerizing of f-actin by this protein is essential for various cellular events, such as endocytosis, phagocytosis, cytokinesis, and cell migration. we show that in the ciliate tetrahymena thermophila, the adf/cofilin homologue adf73p associates with actin on nascent food vacuoles. overexpression of adf73p disrupted the proper localization of actin and inhibited th ... | 2013 | 23729382 |
| ε-tubulin is essential in tetrahymena thermophila for the assembly and stability of basal bodies. | basal bodies and centrioles are conserved microtubule-based organelles the improper assembly of which leads to a number of diseases, including ciliopathies and cancer. tubulin family members are conserved components of these structures that are integral to their proper formation and function. we have identified the ε-tubulin gene in tetrahymena thermophila and detected the protein, through fluorescence of a tagged allele, to basal bodies. immunoelectron microscopy has shown that ε-tubulin locali ... | 2013 | 23704354 |
| localization and functional analysis of hmgb3p, a novel protein containing high-mobility-group-box domain from tetrahymena thermophila. | the high-mobility-group (hmg)-box domain represents a very versatile protein domain that mediates the dna-binding of non-sequence-specific and sequence-specific proteins. hmg-box proteins are involved in various nuclear functions, including modulating chromatin structure and genomic stability. in this study, we identified the gene hmgb3 in tetrahymena thermophila. the predicted hmgb3p contained a single hmg-box, an sk-rich-repeat domain and a neutral phosphorylated c-terminal. hmgb3 was expresse ... | 2013 | 23685281 |
| characterization of ttalv2, an essential charged repeat motif protein of the tetrahymena thermophila membrane skeleton. | alveolins are a recently described class of proteins common to all members of the superphylum alveolata that are characterized by conserved charged repeat motifs (crms) but whose exact function remains unknown. we have analyzed the smaller of the two alveolins of tetrahymena thermophila, ttalv2. the protein localizes to dispersed, broken patches arranged between the rows of the longitudinal microtubules. macronuclear knockdown of ttalv2 leads to multinuclear cells with no apparent cell polarity ... | 2013 | 23606287 |
| the sterol-c7 desaturase from the ciliate tetrahymena thermophila is a rieske oxygenase, which is highly conserved in animals. | the ciliate tetrahymena thermophila incorporates sterols from its environment that desaturates at positions c5(6), c7(8), and c22(23). phytosterols are additionally modified by removal of the ethyl group at carbon 24 (c24). the enzymes involved are oxygen-, nad(p)h-, and cytochrome b5 dependent, reason why they were classified as members of the hydroxylases/desaturases superfamily. the ciliate's genome revealed the presence of seven putative sterol desaturases belonging to this family, two of wh ... | 2013 | 23603937 |
| phlp2 is essential and plays a role in ciliogenesis and microtubule assembly in tetrahymena thermophila. | recent studies have implicated the phosducin-like protein-2 (phlp2) in regulation of cct, a chaperonin whose activity is essential for folding of tubulin and actin. however, the exact molecular function of phlp2 is unclear. here we investigate the significance of phlp2 in a ciliated unicellular model, tetrahymena thermophila, by deleting its single homolog, phlp2p. cells lacking phlp2p became larger and died within 96 h. overexpressed phlp2p-ha localized to cilia, basal bodies, and cytosol witho ... | 2013 | 23588994 |
| a single cohesin complex performs mitotic and meiotic functions in the protist tetrahymena. | the cohesion of sister chromatids in the interval between chromosome replication and anaphase is important for preventing the precocious separation, and hence nondisjunction, of chromatids. cohesion is accomplished by a ring-shaped protein complex, cohesin; and its release at anaphase occurs when separase cleaves the complex's α-kleisin subunit. cohesin has additional roles in facilitating dna damage repair from the sister chromatid and in regulating gene expression. we tested the universality o ... | 2013 | 23555314 |
| selecting one of several mating types through gene segment joining and deletion in tetrahymena thermophila. | the unicellular eukaryote tetrahymena thermophila has seven mating types. cells can mate only when they recognize cells of a different mating type as non-self. as a ciliate, tetrahymena separates its germline and soma into two nuclei. during growth the somatic nucleus is responsible for all gene transcription while the germline nucleus remains silent. during mating, a new somatic nucleus is differentiated from a germline nucleus and mating type is decided by a stochastic process. we report here ... | 2013 | 23555191 |
| the architecture of tetrahymena telomerase holoenzyme. | telomerase adds telomeric repeats to chromosome ends using an internal rna template and a specialized telomerase reverse transcriptase (tert), thereby maintaining genome integrity. little is known about the physical relationships among protein and rna subunits within a biologically functional holoenzyme. here we describe the architecture of tetrahymena thermophila telomerase holoenzyme determined by electron microscopy. six of the seven proteins and the tert-binding regions of telomerase rna (te ... | 2013 | 23552895 |
| discovery and functional evaluation of ciliary proteins in tetrahymena thermophila. | the ciliate tetrahymena thermophila is an excellent model system for the discovery and functional studies of ciliary proteins. the power of the model is based on the ease with which cilia can be purified in large quantities for fractionation and proteomic identification, and the ability to knock out any gene by homologous dna recombination. here, we include methods used by our laboratories for isolation and fractionation of cilia, in vivo tagging and localization of ciliary proteins, and the eva ... | 2013 | 23522474 |
| tetrahymena functional genomics database (tetrafgd): an integrated resource for tetrahymena functional genomics. | the ciliated protozoan tetrahymena thermophila is a useful unicellular model organism for studies of eukaryotic cellular and molecular biology. researches on t. thermophila have contributed to a series of remarkable basic biological principles. after the macronuclear genome was sequenced, substantial progress has been made in functional genomics research on t. thermophila, including genome-wide microarray analysis of the t. thermophila life cycle, a t. thermophila gene network analysis based on ... | 2013 | 23482072 |
| stalking the wild tetrahymena. | we live on a microbial planet. microorganisms dominate in terms of numbers of lineages, numbers of organisms, biomass and evolutionary innovations. yet much remains to be learned about our microbial neighbours. we have gotten to know a few species that have been transformed into 'laboratory rats' (i.e. model organisms), but even here our understanding of the natural history of these lineages remains inadequate as there are few data from populations living in natural habitats. zufall et al. (2013 ... | 2013 | 23476937 |
| quantification of histone modifications using ¹⁵n metabolic labeling. | mass spectrometry has made major contributions to recent discoveries in the field of epigenetics, particularly in the characterization of the myriad post-translational modifications (ptms) of histones which are technically challenging to analyze. these new developments have further aroused great interest in development of robust, new mass spectrometric methods to quantitatively study the dynamics of histone modifications. this review covers quantitative analysis of histone ptms and discuss an ¹⁵ ... | 2013 | 23454290 |
| insights into diseases of human telomerase from dynamical modeling. | mutations in the telomerase complex disrupt either nucleic acid binding or catalysis, and are the cause of numerous human diseases. despite its importance, the structure of the human telomerase complex has not been observed crystallographically, nor are its dynamics understood in detail. fragments of this complex from tetrahymena thermophila and tribolium castaneum have been crystallized. biochemical probes provide important insight into dynamics. in this work we summarize evidence that the t. c ... | 2013 | 23424125 |
| xrrm: a new class of rrm found in the telomerase la family protein p65. | genuine la and la-related proteins group 7 (larp7) bind to the non-coding rnas transcribed by rna polymerase iii (rnapiii), which end in uuu-3'oh. the la motif and rrm1 of these proteins (the la module) cooperate to bind the uuu-3'oh, protecting the rna from degradation, while other domains may be important for rna folding or other functions. among the rnapiii transcripts is ciliate telomerase rna (ter). p65, a member of the larp7 family, is an integral tetrahymena thermophila telomerase holoenz ... | 2013 | 23328630 |
| extracellular conversion of silver ions into silver nanoparticles by protozoan tetrahymena thermophila. | in the current study, cell-free exudates of the ciliated protozoan tetrahymena thermophila were shown to progressively convert silver nitrate to silver nanoparticles (ag nps) under illumination at ambient temperature. the formation of ag nps in the reaction mixture was evidenced by gradual colour changes, appearance of a specific absorbance peak (420–450 nm) and visualization using scanning electron microscopy coupled to an energy-dispersive x-ray spectrometer. after 2 h of incubation the mean h ... | 2013 | 24592441 |
| the zinc finger protein zfr1p is localized specifically to conjugation junction and required for sexual development in tetrahymena thermophila. | conjugation in tetrahymena thermophila involves a developmental program consisting of three prezygotic nuclear divisions, pronuclear exchange and fusion, and postzygotic and exconjugant stages. the conjugation junction structure appears during the initiation of conjugation development, and disappears during the exconjugant stage. many structural and functional proteins are involved in the establishment and maintenance of the junction structure in t. thermophila. in the present study, a zinc fing ... | 2012 | 23251712 |
| quantitative proteomics reveals that the specific methyltransferases txr1p and ezl2p differentially affect the mono-, di- and trimethylation states of histone h3 lysine 27 (h3k27). | nuclear dna in eukaryotic cells is assembled into the hierarchical chromatin structure via a process that is dynamically affected by the combinatorial set of post-translational modifications (ptms) of histones in a dynamic manner responsive to physiological and environmental changes. the precise quantification of these complex modifications is challenging. here we present a robust ms-based quantitative proteomics method for studying histone ptms using (15)n metabolically labeled histones as the ... | 2013 | 23150054 |
| restricted distribution and limited gene flow in the model ciliate tetrahymena thermophila. | the biogeography of microbial eukaryotes has long been debated, but few phylogeographic data have been available to assess whether protists tend to have ubiquitous or endemic distributions. we addressed this issue in the ciliate tetrahymena thermophila, a highly successful model system in cell and molecular biology. we found that this species has a distribution that is restricted to the eastern united states, with high diversity in the northeast and low diversity across the rest of its distribut ... | 2013 | 23094694 |
| the two human centrin homologues have similar but distinct functions at tetrahymena basal bodies. | centrins are a ubiquitous family of small ca(2+)-binding proteins found at basal bodies that are placed into two groups based on sequence similarity to the human centrins 2 and 3. analyses of basal body composition in different species suggest that they contain a centrin isoform from each group. we used the ciliate protist tetrahymena thermophila to gain a better understanding of the functions of the two centrin groups and to determine their potential redundancy. we have previously shown that th ... | 2012 | 23087207 |
| a tetrahymena piwi bound to mature trna 3' fragments activates the exonuclease xrn2 for rna processing in the nucleus. | emerging evidence suggests that argonaute (ago)/piwi proteins have diverse functions in the nucleus and cytoplasm, but the molecular mechanisms employed in the nucleus remain poorly defined. the tetrahymena thermophila ago/piwi protein twi12 is essential for growth and functions in the nucleus. twi12-bound small rnas (srnas) are 3' trna fragments that contain modified bases and thus are attenuated for base pairing to targets. we show that twi12 assembles an unexpected complex with the nuclear ex ... | 2012 | 23084833 |
| is evolution of mating preferences inevitable? random mating in the multisex system of tetrahymena thermophila. | ciliate mating systems are highly diversified, providing unique opportunities to study sexual differentiation and its implications for mating dynamics. many species of ciliates have multiple (>2) sexes. more sexes may mean more choice and an opportunity for evolution of preferential mating. we asked if the multiple sexes of the ciliate tetrahymena thermophila mate preferentially among each other. we quantified pairing frequencies among four sexes of t. thermophila using experiments that allowed ... | 2012 | 23056994 |
| hydrodynamic trapping of tetrahymena thermophila for the long-term monitoring of cell behaviors. | microfluidic trapping technology has been widely applied for single-cell observation in order to reveal characteristic cell behaviors. however, this strategy has yet to be tested for monitoring highly motile cells, which are often biologically important. in this paper, we seek the conditions that enable effective and long-term trapping of a prominent model ciliate tetrahymena thermophila within a hydrodynamic microfluidic device. although motility and flexibility of t. thermophila make it diffic ... | 2012 | 22825740 |