| evolutionary dynamics of a conserved sequence motif in the ribosomal genes of the ciliate paramecium. | in protozoa, the identification of preserved motifs by comparative genomics is often impeded by difficulties to generate reliable alignments for non-coding sequences. moreover, the evolutionary dynamics of regulatory elements in 3' untranslated regions (both in protozoa and metazoa) remains a virtually unexplored issue. | 2010 | 20441586 |
| a small family of elements with long inverted repeats is located near sites of developmentally regulated dna rearrangement in tetrahymena thermophila. | extensive dna rearrangement occurs during the development of the somatic macronucleus from the germ line micronucleus in ciliated protozoans. the micronuclear junctions and the macronuclear product of a developmentally regulated dna rearrangement in tetrahymena thermophila, tlr1, have been cloned. the intrachromosomal rearrangement joins sequences that are separated by more than 13 kb in the micronucleus with the elimination of moderately repeated micronucleus-specific dna sequences. there is a ... | 1994 | 8065327 |
| phylogenomic analysis of integral diiron membrane histidine motif-containing enzymes in ciliates provides insights into their function and evolutionary relationships. | the integral membrane histidine motif-containing enzymes (imhme) are a class of binuclear non-heme iron proteins widely distributed among prokaryotes and eukaryotes. they are characterized by a conserved tripartite motif consisting of eight to ten histidine residues. their known function is the activation of the dioxygen moiety to serve as efficient catalysts for reactions of hydroxylation, desaturation or reduction. to date most studies on imhme were carried out in metazoan, phototrophic or par ... | 2017 | 28559213 |
| a comparative in-silico analysis of autophagy proteins in ciliates. | autophagy serves as a turnover mechanism for the recycling of redundant and/or damaged macromolecules present in eukaryotic cells to re-use them under starvation conditions via a double-membrane structure known as autophagosome. a set of eukaryotic genes called autophagy-related genes (atgs) orchestrate this highly elaborative process. the existence of these genes and the role they play in different eukaryotes are well-characterized. however, little is known of their role in some eukaryotes such ... | 2017 | 28123910 |
| two in vitro methods for screening potential parasiticides against ichthyophthirius multifiliis using tetrahymena thermophila. | ichthyophthirius multifiliis (ich) is a ciliate parasite that infects many species of freshwater fishes worldwide and causes heavy economic losses in aquaculture. currently, parasiticides for controlling this parasite are limited, and few pond-practical chemical therapies exist. hence, the search for new parasiticides is urgently needed. one challenge confronting the screening of potential parasiticides is the difficulty in raising enough parasite for efficacy testing as ich is an obligate paras ... | 2016 | 25857201 |
| molecular genetic diversity and characterization of conjugation genes in the fish parasite ichthyophthirius multifiliis. | ichthyophthirius multifiliis is the etiologic agent of "white spot", a commercially important disease of freshwater fish. as a parasitic ciliate, i. multifiliis infects numerous host species across a broad geographic range. although ichthyophthirius outbreaks are difficult to control, recent sequencing of the i. multifiliis genome has revealed a number of potential metabolic pathways for therapeutic intervention, along with likely vaccine targets for disease prevention. nonetheless, major gaps e ... | 2015 | 25743182 |
| comparative genomic analysis of integral membrane transport proteins in ciliates. | integral membrane transport proteins homologous to those found in the transporter classification database (tcdb; www.tcdb.org) were identified and bioinformatically characterized by transporter class, family, and substrate specificity in three ciliates, paramecium tetraurelia (para), tetrahymena thermophila (tetra), and ichthyophthirius multifiliis (ich). in these three organisms, 1,326 of 39,600 proteins (3.4%), 1,017 of 24,800 proteins (4.2%), and 504 out of 8,100 proteins (6.2%) integral memb ... | 2015 | 25099884 |
| meiosis gene inventory of four ciliates reveals the prevalence of a synaptonemal complex-independent crossover pathway. | to establish which meiosis genes are present in ciliates, and to look for clues as to which recombination pathways may be treaded by them, four genomes were inventoried for 11 meiosis-specific and 40 meiosis-related genes. we found that the set of meiosis genes shared by tetrahymena thermophila, paramecium tetraurelia, ichthyophthirius multifiliis, and oxytricha trifallax is consistent with the prevalence of a mus81-dependent class ii crossover pathway that is considered secondary in most model ... | 2014 | 24336924 |
| molecular and functional evolution of tetrahymena metallothioneins: new insights into the gene family of tetrahymena thermophila. | a new metallothionein (mtt-5) gene isoform has been cloned and characterized from the ciliate tetrahymena thermophila. its amino acid sequence shows only limited similarity with other tetrahymena mts. to investigate the transcriptional activity of this gene toward heavy metals (cd, cu, zn), mrna levels were evaluated by real-time quantitative pcr. results show that the three metals induce different mtt-5-mrna levels, cd treatment eliciting the most effective induction in the first 30 min. phylog ... | 2007 | 17208053 |
| some but not all tetrahymena species destroy monolayer cultures of cells from a wide range of tissues and species. | the activities of tetrahymena corlissi, tetrahymena thermophila, and tetrahymena canadensis were studied in coculture with cell lines of insects, fish, amphibians, and mammals. these ciliates remained viable regardless of the animal cell line partner. all three species could engulf animal cells in suspension. however, if the animal cells were monolayer cultures, the monolayers were obliterated by t. corlissi and t. thermophila. both fibroblast and epithelial monolayers were destroyed but the des ... | 2017 | 25733238 |
| species of tetrahymena identical by small subunit rrna gene sequences are discriminated by mitochondrial cytochrome c oxidase i gene sequences. | the mitochondrial cytochrome c oxidase 1 (co1) genes of two isolates of each of the seven mating types of tetrahymena thermophila were sequenced and found to differ by < 1% in nucleotide sequence and to be identical by putative protein sequence. as this gene was highly conserved in this species, the co1 gene sequence was determined for four pairs of tetrahymena species identical in their small subunit rrna gene sequences. the following pairs of species showed from 1% to 12% divergence at the nuc ... | 2006 | 16968457 |
| barcoding tetrahymena: discriminating species and identifying unknowns using the cytochrome c oxidase subunit i (cox-1) barcode. | dna barcoding using the mitochondrial cytochromecoxidase subunit i (cox-1) gene has recently gained popularity as a tool for species identification of a variety of taxa. the primary objective of our research was to explore the efficacy of using cox-1 barcoding for species identification within the genustetrahymena. we first increased intraspecific sampling fortetrahymena canadensis, tetrahymena hegewischi, tetrahymena pyriformis, tetrahymena rostrata, tetrahymena thermophila, and tetrahymena tro ... | 2011 | 20708435 |
| extensive changes in the locations and sequence content of developmentally deleted dna between tetrahymena thermophila and its closest relative, t. malaccensis. | tetrahymena thermophila has two different types of nuclei in a single cell. the development of the transcriptionally active macronucleus from a transcriptionally inert micronucleus is accompanied by the elimination of numerous dna segments, called deletion elements or internally eliminated sequences (iess). to try to distinguish between alternative modes for the generation of iess during evolution, dna sequences at three loci that contain iess in t. thermophila were examined in tetrahymena malac ... | 2007 | 17300523 |
| identification, cloning and sequencing of a novel stress inducible metallothionein gene from locally isolated tetrahymena tropicalis lahorensis. | a novel cadmium inducible metallothionein (tmcd1) gene has been identified and sequenced from the locally isolated ciliate, tetrahymena tropicalis lahorensis from industrial effluents. the tmcd1 gene encodes 471 nucleotides, with tga as the stop codon and taa coding for glutamine. this new gene is quite different from the previously reported mt genes in tetrahymena pyriformis and tetrahymena pigmentosa. however, it shows 78% homology with four different cd-mt genes reported from tetrahymena ther ... | 2007 | 17949926 |
| cloning and characterization of a new multi-stress inducible metallothionein gene in tetrahymena pyriformis. | a new multi-stress-inducible metallothionein (mt) gene isoform has been cloned and characterized from the ciliate tetrahymena pyriformis. both the 5'- and 3'-ut regions of the tp-mt2 gene are very different from the previously reported tp-mt1 isoform in this organism and from other described mt genes in tetrahymena pigmentosa and tetrahymena thermophila. the putative protein sequence of tp-mt2 contains cysteine clusters with characteristics of the typical tetrahymena cd-inducible mt genes. howev ... | 2006 | 16621695 |
| genetic instability in the mating type system of tetrahymena pigmentosa. | selfing clones of tetrahymena pigmentosa show several interesting genetic features, and provide some insight into the mechanisms of mating type (mt) determination. they differ significantly from those of tetrahymena thermophila. they are distributed nonrandomly in crosses. their rates of stabilization are highly variable, but most are much lower than those reported for t. thermophila. a number of subclones derived from nearly all the selfers have maintained stable mts in culture for several year ... | 1987 | 3692137 |
| localization of transcribed regions on extrachromosomal ribosomal rna genes of tetrahymena thermophila by r-loop mapping. | r-loop hybridization and electron microscopy were used to map the rna transcription products of the extrachromosomal rrna genes of tetrahymena thermophila. the mature 17s and 26s rrnas and the nuclear 35s pre-rrna and pre-26s rrna were located with a precision of approximately 100 base pairs. a 370-base pair intervening sequence was found in the 26s coding region. it has the same size and relative location as that found in tetrahymena pigmentosa [wild, m.a. & gall, j.g. (1979) cell 16, 565-573]. ... | 1979 | 291921 |
| the fate of multilamellar bodies produced and secreted by dictyostelium discoideum amoebae. | the amoeba dictyostelium discoideum produces and secretes multilamellar bodies (mlbs) mainly composed of amoebal membranes upon digestion of bacteria. after their secretion, the fate of these mlbs remains unknown. the aim of this study was to determine if protozoa can internalize and digest secreted d. discoideum mlbs. our results showed that mlbs were ingested by naive axenic d. discoideum cells (i. e. cells not exposed to bacteria and consequently not producing mlbs). only a small fraction of ... | 2017 | 29107380 |
| amitotic chromosome loss predicts distinct patterns of senescence and non-senescence in ciliates. | over time and repeated asexual divisions, many ciliate species display the characteristics of senescence, reduced fecundity and increased mortality. their only path to recovery is sexual conjugation or autogamy. while more traditional models of cellular aging have been proposed, one of the most accepted explanations relies on the faulty mechanism by which ciliates duplicate their somatic nucleus, a process referred to as amitosis. amitosis involves the random segregation of chromosomes with no c ... | 2015 | 25840368 |
| the effects of supraoptimal temperatures on population growth and cortical patterning in tetrahymena pyriformis and tetrahymena thermophila: a comparison. | in this investigation, we compare the multiplication rates and morphogenetic responses of the two most studied tetrahymena species, t. pyriformis and t. thermophila, at supraoptimal temperatures. although the upper temperature limits differ greatly in the two species, the pattern of growth responses to high temperature is for the most part similar, with some differences in detail. the transient recovery of cell division at the highest temperature that allows cell division, characteristic of t. p ... | 2006 | 12095101 |
| conserved cis- and trans-acting determinants for replication initiation and regulation of replication fork movement in tetrahymenid species. | the rdna minichromosomes of tetrahymena thermophila and tetrahymena pyriformis share a high degree of sequence similarity and structural organization. the t.thermophila 5' non-transcribed spacer (5' nts) is sufficient for replication and contains three repeated sequence elements that are conserved in t.pyriformis , including type i elements, the only known determinant for replication control. to assess the role of conserved sequences in replication control, structural and functional studies were ... | 1998 | 9753731 |
| cloning and characterization of the major histone h2a genes completes the cloning and sequencing of known histone genes of tetrahymena thermophila. | a truncated cdna clone encoding tetrahymena thermophila histone h2a2 was isolated using synthetic degenerate oligonucleotide probes derived from h2a protein sequences of tetrahymena pyriformis. the cdna clone was used as a homologous probe to isolate a truncated genomic clone encoding h2a1. the remaining regions of the genes for h2a1 (hta1) and h2a2 (hta2) were then isolated using inverse pcr on circularized genomic dna fragments. these partial clones were assembled into intact hta1 and hta2 clo ... | 1996 | 8760889 |
| comparison of axonemal proteins from two kinds of tetrahymena. i. different characteristics of dyneins in heat stability. | tetrahymena thermophila could still swim after incubation of the cell body at 40 degrees c for 30 min, whereas tetrahymena pyriformis did not show any motility after the treatment. turbidity measurements revealed that axonemes of t. pyriformis lost atp-dependent sliding activity by the heat treatment, whereas those of t. thermophilia still had the activity under the same conditions. in connection with this difference in susceptibility to high temperature, the biochemical characteristics of dynei ... | 1995 | 8590385 |
| developmental dna rearrangements and micronucleus-specific sequences in five species within the tetrahymena pyriformis species complex. | in tetrahymena thermophila, the development of a transcriptionally active macronucleus from a transcriptionally inert micronucleus includes the elimination of many segments of dna, the bulk of which belong to repetitive sequence families. two approaches were used to study the interspecies variations in developmentally eliminated dna segments. first, the occurrence of restriction fragments crosshybridizing to developmentally eliminated dna segments isolated from t. thermophila was examined in oth ... | 1995 | 8582637 |
| okadaic acid promotes cell division in synchronized tetrahymena pyriformis and in the cell division-arrested (cdaa1) temperature-sensitive mutant of t. thermophila. | 1. okadaic acid (oa) at 0.5 to 1 microm accelerated the onset and completion of division in heat-synchronized tetrahymena pyriformis, especially where cells had been transiently delayed in the presence of dimethyl sulfoxide (dmso). 2. the cell division-arrested mutant, cdaa1, of tetrahymena thermophila ceased dividing after being shifted from the permissive temperature of 22 degrees c to the restrictive temperature of 37 degrees c, but continued to grow without forming fission furrows, resulting ... | 1994 | 8005101 |
| calmodulin cdnas from two species of tetrahymena. | we describe the isolation and characterization of cdnas encoding calmodulins of tetrahymena thermophila and tetrahymena pyriformis. it reveals that the deduced amino acid sequences of both calmodulins are precisely the same. | 1992 | 1339295 |
| in vitro transcription in isolated nucleoli of tetrahymena pyriformis. | an in vitro transcription system was established using extrachromosomal nucleoli from tetrahymena pyriformis macronuclei as a template. ribosomal precursor rna (pre-rrna) and nascent pre-rrna chains were removed from isolated nucleoli by treatment with rnase t1 and sarkosyl. nucleoli were then incubated in a rna synthetic cocktail containing a cellular extract from tetrahymena thermophila. the transcription product was examined for the presence of transcripts from t. pyriformis ribosomal dna (rd ... | 1992 | 1379895 |
| the major pterin in tetrahymena pyriformis is 6-(d-threo-1,2,3-trihydroxypropyl)-pterin (d-monapterin) and not 6-(l-threo-1,2-dihydroxypropyl)-pterin (ciliapterin). | the major pterin in tetrahymena pyriformis, strain w, earlier suggested to be l-threo-biopterin and named ciliapterin [1] is now identified as d-threo-neopterin (d-monapterin). this is the first example of a natural d-monapterin. this compound was characterized by its chromatographic behavior, its fluorescence properties and by its oxidation product with alkaline permanganate. the final identification was obtained by comparison with an authentic material using an exchange ligand chromatography m ... | 1991 | 1782220 |
| cadmium-thionein in tetrahymena thermophila and tetrahymena pyriformis. | the treatment of tetrahymena thermophila with cadmium causes a reduction in growth rate according to dose; almost all the metal is accumulated in the cytosol where the zn content is also increased threefold. bio-gel and water 160 (hplc) column chromatography show that cd and zn are bound to a protein with an ultraviolet (uv) spectrum that appears to be similar to that of cd-metallothioneins isolated by higher organisms, but its molecular weight is greater: about 28 000 d, comparable to that of m ... | 1990 | 23196192 |
| taxon-dependence of receptor level cell-to-cell communication in tetrahymena: possible explanation for the transmission of hormonal imprinting. | insulin treatment induced in tetrahymena pyriformis a positive hormonal imprinting, and in tetrahymena thermophila a negative imprinting, resulting in increased and decreased binding capacity, respectively, at re-exposure to the hormone. the imprinting, or the information associated with it, is transferred by the nutrient medium of the insulin-treated cells to those not treated. the issue of transfer depends on the nature of the receiver taxon, leading always to a positive imprinting in tetrahym ... | 1987 | 2824132 |
| the effect of temperature on glyceryl ethers in tetrahymena pyriformis w. | the effect of temperature on the ether content of the glycerophospholipids of tetrahymena pyriformis w was examined. the only ether detected was 1-o-hexadecyl glycerol (alpha-chimyl alcohol). the data provide evidence that the class 1-o-alkyl-2-acyl-sn-glycero-3-(2-aminoethyl)-phosphate (1-alkyl pse), in addition to the previously reported 1-o-alkyl-2-acyl-sn-glycero-3-(2-aminoethyl)-phosphonate (1-alkyl pne) and 1-o-alkyl-2-acyl-sn-glycero-3-phosphorylcholine (1-alkyl pc), exists in this ciliat ... | 1982 | 6819334 |
| nuclease sensitivity of chromatin containing active genes: kinetic analyses utilizing continuous elution of digestion products from an ultrafiltration cell. | methods have been developed to analyze the kinetics of digestion of chromatin by nucleases. radioactively labeled nuclei were incubated with enzyme in an ultrafiltration apparatus and digestion rates of different chromatin samples were computed employing a least-squares curve fitting technique to fit the data to zero-order and/or first-order kinetic models. these methods allow detailed kinetic analyses on small amounts of chromatin. two biological systems were studied. 1) tetrahymena thermophila ... | 1981 | 6273809 |
| replication of the extrachromosomal ribosomal rna genes of tetrahymena thermophilia. | cultures of tetrahymena thermophila were deprived of nutrients and later refed with enriched medium to obtain partial synchrony of dna replication. preferential replication of the extrachromosomal, macronuclear ribosomal rna genes (rdna) was found to occur at 40-80 min after refeeding. the rdna accounted for one half of the label incorporated into cellular dna during this period. electron microscopy of the purified rdna showed 1% replicative intermediates. their structure was that expected for b ... | 1981 | 7279667 |
| evidence for chromosomal macronuclear substructures in tetrahymena. | under the growth conditions employed, the g1 macronucleus of tetrahymena pyriformis hsm contains 7.4 × 10(-12) g dna, the g2 micronucleus 0.42 × 10(-12) g. dna content from the tetrahymena thermophila macronucleus did not significantly differ from that of hsm, but the micronucleus contained about twice as much dna as the micronucleus of the hsm cells. the t. thermophila macronucleus contained on average enough dna for ˜ 35 haploid micronuclear copies. a new spreading technic allowed separation o ... | 1979 | 26306339 |
| exploration of the germline genome of the ciliate chilodonella uncinata through single-cell omics (transcriptomics and genomics). | separate germline and somatic genomes are found in numerous lineages across the eukaryotic tree of life, often separated into distinct tissues (e.g., in plants, animals, and fungi) or distinct nuclei sharing a common cytoplasm (e.g., in ciliates and some foraminifera). in ciliates, germline-limited (i.e., micronuclear-specific) dna is eliminated during the development of a new somatic (i.e., macronuclear) genome in a process that is tightly linked to large-scale genome rearrangements, such as de ... | 2018 | 29317511 |
| label-free imaging of nanoparticle uptake competition in single cells by hyperspectral stimulated raman scattering. | imaging and quantification of nanoparticles in single cells in their most natural condition are expected to facilitate the biotechnological applications of nanoparticles and allow for better assessment of their biosafety risks. however, current imaging modalities either require tedious sample preparation or only apply to nanoparticles with specific physicochemical characteristics. here, the emerging hyperspectral stimulated raman scattering (srs) microscopy, as a label-free and nondestructive im ... | 2017 | 29283225 |
| bioaccumulation of 14c-labeled graphene in an aquatic food chain through direct uptake or trophic transfer. | the growing applications of graphene materials warrant a careful evaluation of their environmental fate in aquatic food webs. escherichia coli (bacteria), tetrahymena thermophila (protozoa), daphnia magna (zooplankton), and danio rerio (vertebrate) were used to build aquatic food chains to investigate the waterborne uptake and trophic transfer of 14c-labeled graphene. body burden factor (bbf) and trophic transfer factor (ttf) were analyzed for each organism and food chain to assess the bioaccumu ... | 2018 | 29265813 |
| elemental sulfur reduction to h2s by tetrahymena thermophila. | eukaryotic nucleocytoplasm is believed to be descended from ancient archaea that respired on elemental sulfur. if so, a vestige of sulfur reduction might persist in modern eukaryotic cells. that was tested in tetrahymena thermophila, chosen as a model organism. when oxygenated, the cells consumed h2s rapidly, but when made anoxic they produced h2s mostly by amino acid catabolism. that could be inhibited by adding aminooxyacetic acid, and then h2s production from elemental sulfur became more evid ... | 2017 | 29248819 |
| condensins promote chromosome individualization and segregation during mitosis, meiosis, and amitosis in tetrahymena thermophila. | condensin is a protein complex with diverse functions in chromatin packaging and chromosome condensation and segregation. we studied condensin in the evolutionarily distant protist model tetrahymena, which features non-canonical nuclear organization and divisions. in tetrahymena, the germline and soma are partitioned into two different nuclei within a single cell. consistent with their functional specializations in sexual reproduction and gene expression, condensins of the germline nucleus and t ... | 2017 | 29237819 |
| small phosphatidate phosphatase (ttpah2) of tetrahymena complements respiratory function and not membrane biogenesis function of yeast pah1. | phosphatidate phosphatases (pah) play a central role in lipid metabolism and intracellular signaling. herein, we report the presence of a low-molecular-weight pah homolog in the single-celled ciliate tetrahymena thermophila. in vitro phosphatase assay showed that ttpah2 belongs to the magnesium-dependent phosphatidate phosphatase (pap1) family. loss of function of ttpah2 did not affect the growth of tetrahymena. unlike other known pah homologs, ttpah2 did not regulate lipid droplet number and er ... | 2017 | 29229879 |
| extreme metal adapted, knockout and knockdown strains reveal a coordinated gene expression among different tetrahymena thermophila metallothionein isoforms. | metallothioneins (mt) constitute a superfamily of small cytosolic proteins that are able to bind metal cations through numerous cysteine (cys) residues. like other organisms the ciliate tetrahymena thermophila presents several mt isoforms, which have been classified into two subfamilies (cd- and cu-metallothioneins). the main aim of this study was to examine the specific functions and transcriptional regulation of the five mt isoforms present in t. thermophila, by using several strains of this c ... | 2017 | 29206858 |
| enantioselective transformation of fluoxetine in water and its ecotoxicological relevance. | european legislation focusing on water quality is expected to broaden to encompass several pharmaceuticals as priority hazardous substances. this manuscript aims to challenge current regulatory approaches that do not recognize stereochemistry of chiral pharmaceuticals by testing the hypothesis that environmental transformation and effects of chiral pharmaceuticals are stereoselective. our experiments revealed that, while degradation of chiral fluoxetine (fl) in river water occurs via non-enantio ... | 2017 | 29150682 |
| the co-regulation data harvester: automating gene annotation starting from a transcriptome database. | identifying co-regulated genes provides a useful approach for defining pathway-specific machinery in an organism. to be efficient, this approach relies on thorough genome annotation, a process much slower than genome sequencing per se. tetrahymena thermophila, a unicellular eukaryote, has been a useful model organism and has a fully sequenced but sparsely annotated genome. one important resource for studying this organism has been an online transcriptomic database. we have developed an automated ... | 2017 | 29104906 |
| micronucleus-specific histone h1 is required for micronuclear chromosome integrity in tetrahymena thermophila. | histone h1 molecules play a key role in establishing and maintaining higher order chromatin structures. they can bind to linker dna entering and exiting the nucleosome and regulate transcriptional activity. tetrahymena thermophila has two histone h1, namely, macronuclear histone h1 and micronuclear histone h1 (mlh1). mlh1 is specifically localized at micronuclei during growth and starvation stages. moreover, mlh1 is localized around micronuclei and forms a specific structure during the conjugati ... | 2017 | 29095884 |
| functional analysis of metallothionein mtt5 from tetrahymena thermophila. | metallothioneins (mts) constitute a superfamily of cysteine-rich proteins that bind heavy-metal ions by metal-thiolate clusters. five mt genes from tetrahymena thermophila was subdivided into 7a (mtt1, mtt3, and mtt5) and 7b (mtt2 and mtt4) subfamilies. in the study, mtt5 was knocked out in tetrahymena. the mutant cells were sensitive to cd2+ and pb2+ but poorly sensitive to cu+ . in the mtt5 knockout cells, the expression levels of mtt1 and mtt3 were significantly up-regulated under cd2+ and pb ... | 2017 | 29091311 |
| n6-adenine dna methylation is associated with the linker dna of h2a.z-containing well-positioned nucleosomes in pol ii-transcribed genes in tetrahymena. | dna n6-methyladenine (6ma) is newly rediscovered as a potential epigenetic mark across a more diverse range of eukaryotes than previously realized. as a unicellular model organism, tetrahymena thermophila is among the first eukaryotes reported to contain 6ma modification. however, lack of comprehensive information about 6ma distribution hinders further investigations into its function and regulatory mechanism. in this study, we provide the first genome-wide, base pair-resolution map of 6ma in te ... | 2017 | 29036602 |
| whats, hows and whys of programmed dna elimination in tetrahymena. | programmed genome rearrangements in ciliates provide fascinating examples of flexible epigenetic genome regulations and important insights into the interaction between transposable elements (tes) and host genomes. dna elimination in tetrahymena thermophila removes approximately 12 000 internal eliminated sequences (iess), which correspond to one-third of the genome, when the somatic macronucleus (mac) differentiates from the germline micronucleus (mic). more than half of the iess, many of which ... | 2017 | 29021213 |
| evolutionary contribution to coexistence of competitors in microbial food webs. | the theory of species coexistence is a key concept in ecology that has received much attention. the role of rapid evolution for determining species coexistence is still poorly understood although evolutionary change on ecological time-scales has the potential to change almost any ecological process. the influence of evolution on coexistence can be especially pronounced in microbial communities where organisms often have large population sizes and short generation times. previous work on coexiste ... | 2017 | 29021178 |
| evolution of density-dependent movement during experimental range expansions. | range expansions and biological invasions are prime examples of transient processes that are likely impacted by rapid evolutionary changes. as a spatial process, range expansions are driven by dispersal and movement behaviour. although it is widely accepted that dispersal and movement may be context-dependent, for instance density-dependent, and best represented by reaction norms, the evolution of density-dependent movement during range expansions has received little experimental attention. we t ... | 2017 | 28977712 |
| an evolutionarily conserved phosphatidate phosphatase maintains lipid droplet number and endoplasmic reticulum morphology but not nuclear morphology. | phosphatidic acid phosphatases are involved in the biosynthesis of phospholipids and triacylglycerol, and also act as transcriptional regulators. studies to ascertain their role in lipid metabolism and membrane biogenesis are restricted to opisthokonta and archaeplastida. here, we report the role of phosphatidate phosphatase (pah) in tetrahymena thermophila, belonging to the alveolata clade. we identified two pah homologs in tetrahymena, ttpah1 and ttpah2 loss of function of ttpah1 results in re ... | 2017 | 28954739 |
| a germline-limited piggybac transposase gene is required for precise excision in tetrahymena genome rearrangement. | developmentally programmed genome rearrangement accompanies differentiation of the silent germline micronucleus into the transcriptionally active somatic macronucleus in the ciliated protozoan tetrahymena thermophila. internal eliminated sequences (ies) are excised, followed by rejoining of mac-destined sequences, while fragmentation occurs at conserved chromosome breakage sequences, generating macronuclear chromosomes. some macronuclear chromosomes, referred to as non-maintained chromosomes (nm ... | 2017 | 28934495 |
| uptake of cholesterol by tetrahymena thermophila is mainly due to phagocytosis. | | 2017 | 28916309 |
| a comparative study of genome organization and epigenetic mechanisms in model ciliates, with an emphasis on tetrahymena, paramecium and oxytricha. | as a group of unicellular eukaryotes, ciliates offer a unique system to explore epigenetic regulation, mostly due to their nuclear dualism. ciliates launched a successful radiation after their early evolutionary branching, therefore harboring an unexpectedly rich pool of diverse biological functions and mechanisms. in this review, we compare distinct features of different ciliates in mating type determination, genome organization, dna methylation, and removal of internal eliminated sequences (ie ... | 2017 | 28735853 |
| human cst prefers g-rich but not necessarily telomeric sequences. | the human cst (ctc1-stn1-ten1) heterotrimeric complex plays roles in both telomere maintenance and dna replication through its ability to interact with single-stranded dna (ssdna) of a variety of sequences. the precise sequence specificity required to execute these functions is unknown. telomere-binding proteins have been shown to specifically recognize key telomeric sequence motifs within ssdna while accommodating nonspecifically recognized sequences through conformationally plastic interfaces. ... | 2017 | 28726394 |
| diversification of hp1-like chromo domain proteins in tetrahymena thermophila. | proteins that possess a chromo domain are well-known for their roles in heterochromatin assembly and maintenance. the heterochromatin protein 1 (hp1) family, with a chromo domain and carboxy-terminal chromo shadow domain, targets heterochromatin through interaction with histone h3 methylated on lysine 9 (h3k9me2/3). the structural and functional diversity of these proteins observed in both fission yeast and metazoans correlate with chromatin specialization. to expand these studies, we examined c ... | 2018 | 28692189 |
| behavioral effects of a chemorepellent receptor knockout mutation in tetrahymena thermophila. | a conditioned supernatant from tetrahymena thermophila contains a powerful chemorepellent for wild-type cells, and a gene called g37 is required for this response. this is the first genomic identification of a chemorepellent receptor in any eukaryotic unicellular organism. this conditioned supernatant factor (csf) is small (<1 kda), and its repellent effect is resistant to boiling, protease treatment, and nuclease digestion. external bapta eliminated the csf response, suggesting that ca2+ entry ... | 2017 | 28685161 |
| post-meiotic dna double-strand breaks occur in tetrahymena, and require topoisomerase ii and spo11. | based on observations of markers for dna lesions, such as phosphorylated histone h2ax (γh2ax) and open dna ends, it has been suggested that post-meiotic dna double-strand breaks (pm-dsbs) enable chromatin remodeling during animal spermiogenesis. however, the existence of pm-dsbs is unconfirmed, and the mechanism responsible for their formation is unclear. here, we report the first direct observation of programmed pm-dsbs via the electrophoretic separation of dsb-generated dna fragments in the ci ... | 2017 | 28621664 |
| ift trains in different stages of assembly queue at the ciliary base for consecutive release into the cilium. | intraflagellar transport (ift) trains, multimegadalton assemblies of ift proteins and motors, traffic proteins in cilia. to study how trains assemble, we employed fluorescence protein-tagged ift proteins in chlamydomonas reinhardtii. ift-a and motor proteins are recruited from the cell body to the basal body pool, assembled into trains, move through the cilium, and disperse back into the cell body. in contrast to this 'open' system, ift-b proteins from retrograde trains reenter the pool and a po ... | 2017 | 28562242 |
| identification of the zinc, copper and cadmium metalloproteome of the protozoon tetrahymena thermophila by systematic bioinformatics. | tetrahymena thermophila (t. thermophila) is a ciliated protozoon that can detect freshwater pollution by heavy metals ("whole-cell biosensor"). this work employed a systematic bioinformatics approach to predict and analyze the metalloproteome of t. thermophila for the essential zn, cu and the non-essential cd. 3784 metal-binding proteins were identified compared to the 456 annotated so far in uniprot. the localization, functional classification, and the functionally enriched network of the newly ... | 2017 | 28478602 |
| the hippo pathway maintains the equatorial division plane in the ciliate tetrahymena. | the mechanisms that govern pattern formation within the cell are poorly understood. ciliates carry on their surface an elaborate pattern of cortical organelles that are arranged along the anteroposterior and circumferential axes by largely unknown mechanisms. ciliates divide by tandem duplication: the cortex of the predivision cell is remodeled into two similarly sized and complete daughters. in the conditional cdai-1 mutant of tetrahymena thermophila, the division plane migrates from its initia ... | 2017 | 28413159 |
| nonsense-mediated mrna decay in tetrahymena is ejc independent and requires a protozoa-specific nuclease. | nonsense-mediated mrna decay (nmd) is essential for removing premature termination codon-containing transcripts from cells. studying the nmd pathway in model organisms can help to elucidate the nmd mechanism in humans and improve our understanding of how this biologically important process has evolved. ciliates are among the earliest branching eukaryotes; their nmd mechanism is poorly understood and may be primordial. we demonstrate that highly conserved upf proteins (upf1a, upf2 and upf3) are i ... | 2017 | 28402567 |
| compositionally distinct nuclear pore complexes of functionally distinct dimorphic nuclei in the ciliate tetrahymena. | the nuclear pore complex (npc), a gateway for nucleocytoplasmic trafficking, is composed of ∼30 different proteins called nucleoporins. it remains unknown whether the npcs within a species are homogeneous or vary depending on the cell type or physiological condition. here, we present evidence for compositionally distinct npcs that form within a single cell in a binucleated ciliate. in tetrahymena thermophila, each cell contains both a transcriptionally active macronucleus (mac) and a germline mi ... | 2017 | 28386019 |
| an endosomal syntaxin and the ap-3 complex are required for formation and maturation of candidate lysosome-related secretory organelles (mucocysts) in tetrahymena thermophila. | the ciliate tetrahymena thermophila synthesizes large secretory vesicles called mucocysts. mucocyst biosynthesis shares features with dense core granules (dcgs) in animal cells, including proteolytic processing of cargo proteins during maturation. however, other molecular features have suggested relatedness to lysosome-related organelles (lros). lros, which include diverse organelles in animals, are formed via convergence of secretory and endocytic trafficking. here we analyzed tetrahymena synta ... | 2017 | 28381425 |
| tetrahymena phagocytic vesicles as ecological micro-niches of phage transfer. | the microbial communities in natural environments such as soil, pond water, or animal rumens are composed of a diverse mixture of bacteria and protozoa including ciliates or flagellates. in such microbiomes, a major source of bacterial mortality is grazing by phagocytic protists. many protists are omnivorous heterotrophs, feeding on a range of different bacterial species. due to this indiscriminate feeding, different bacterial species can assemble together in the same phagocytic vesicles where t ... | 2017 | 28334205 |
| mechanisms of toxic action of silver nanoparticles in the protozoan tetrahymena thermophila: from gene expression to phenotypic events. | silver nanoparticles (agnps) are highly toxic to aquatic organisms, however, there is no consensus whether the toxicity is caused solely by released ag-ions or also by reactive oxygen species (ros). here, the effects of protein-coated agnps (14.6 nm, collargol) were studied on viability, oxidative stress and gene expression levels in wild type strains (cu427 and cu428) of ciliate tetrahymena thermophila. viability-based 24 h ec50 values of agnps were relatively high and significantly different f ... | 2017 | 28318795 |
| n6-methyladenine dna modification in the unicellular eukaryotic organism tetrahymena thermophila. | n6-methyladenine dna (6ma) modification exists in both prokaryotes and eukaryotes in which it plays a crucial role in regulating numerous biological processes. in prokaryotes, 6ma is a marker to distinguish self from foreign dna. its role in eukaryotes, however, remains elusive. ciliates were among the first eukaryotes reported to contain 6ma. in the model organism t. thermophila, cellular localization and features of 6ma have been extensively studied, especially in ribosomal dna (rdna) molecule ... | 2017 | 28135687 |
| the piggybac transposon-derived genes tpb1 and tpb6 mediate essential transposon-like excision during the developmental rearrangement of key genes in tetrahymena thermophila. | ciliated protozoans perform extreme forms of programmed somatic dna rearrangement during development. the model ciliate tetrahymena thermophila removes 34% of its germline micronuclear genome from somatic macronuclei by excising thousands of internal eliminated sequences (iess), a process that shares features with transposon excision. indeed, piggybac transposon-derived genes are necessary for genome-wide ies excision in both tetrahymena (tpb2 [tetrahymena piggybac-like 2] and lia5) and parameci ... | 2016 | 28087716 |
| one genome's junk is another's garbage. | experiments on a single-celled ciliate reveal how mobile genetic elements can shape a genome, even one which is not transcriptionally active. | 2016 | 28008854 |
| heterochromatin aggregation during dna elimination in tetrahymena is facilitated by a prion-like protein. | regulated aggregations of prion and prion-like proteins play physiological roles in various biological processes. however, their structural roles in the nucleus are poorly understood. here, we show that the prion-like protein jub6p is involved in the regulation of chromatin structure in the ciliated protozoan tetrahymena thermophila jub6p forms sodium dodecyl sulfate (sds)-resistant aggregates when it is ectopically expressed in vegetative cells and binds to rna in vitro jub6p is a heterochromat ... | 2017 | 27909245 |
| shared subunits of tetrahymena telomerase holoenzyme and replication protein a have different functions in different cellular complexes. | in most eukaryotes, telomere maintenance relies on telomeric repeat synthesis by a reverse transcriptase named telomerase. to synthesize telomeric repeats, the catalytic subunit telomerase reverse transcriptase (tert) uses the rna subunit (ter) as a template. in the ciliate tetrahymena thermophila, the telomerase holoenzyme consists of ter, tert, and eight additional proteins, including the telomeric repeat single-stranded dna-binding protein teb1 and its heterotrimer partners teb2 and teb3. teb ... | 2017 | 27895115 |
| structure of the germline genome of tetrahymena thermophila and relationship to the massively rearranged somatic genome. | the germline genome of the binucleated ciliate tetrahymena thermophila undergoes programmed chromosome breakage and massive dna elimination to generate the somatic genome. here, we present a complete sequence assembly of the germline genome and analyze multiple features of its structure and its relationship to the somatic genome, shedding light on the mechanisms of genome rearrangement as well as the evolutionary history of this remarkable germline/soma differentiation. our results strengthen th ... | 2016 | 27892853 |
| e2fl1 is a meiosis-specific transcription factor in the protist tetrahymena thermophila. | members of the e2f family of transcription factors have been reported to regulate the expression of genes involved in cell cycle control, dna replication, and dna repair in multicellular eukaryotes. here, e2fl1, a meiosis-specific e2f transcription factor gene, was identified in the model ciliate tetrahymena thermophila. loss of this gene resulted in meiotic arrest prior to anaphase i. the cytological experiments revealed that the meiotic homologous pairing was not affected in the absence of e2f ... | 2017 | 27892792 |
| in vivo synthesis of nano-selenium by tetrahymena thermophila sb210. | nano-selenium has a great potential to be used in chemical, biological, medical and environmental fields. biological methods for nano-selenium synthesis have attracted wide interests, because they can be operated at ambient temperature and pressure without complicated equipments. in this work, a protozoa, tetrahymena thermophila (t. thermophila) sb210, was used to in vivo synthesize nano-selenium. the biosynthesized nano-selenium was characterized using transmission electron microscopy, energy d ... | 2016 | 27866614 |
| programmed minichromosome elimination as a mechanism for somatic genome reduction in tetrahymena thermophila. | the maintenance of chromosome integrity is crucial for genetic stability. however, programmed chromosome fragmentations are known to occur in many organisms, and in the ciliate tetrahymena the five germline chromosomes are fragmented into hundreds of minichromosomes during somatic nuclear differentiation. here, we showed that there are different fates of these minichromosomes after chromosome breakage. among the 326 somatic minichromosomes identified using genomic data, 50 are selectively elimin ... | 2016 | 27806059 |
| regulation of katanin activity in the ciliate tetrahymena thermophila. | katanin is a microtubule severing protein that functions as a heterodimer composed of an aaa domain catalytic subunit, p60, and a regulatory subunit, a wd40 repeat protein, p80. katanin-dependent severing of microtubules is important for proper execution of key cellular activities including cell division, migration, and differentiation. published data obtained in caenorhabditis elegans, xenopus and mammals indicate that katanin is regulated at multiple levels including transcription, posttransla ... | 2017 | 27726198 |
| an evolutionary balance: conservation vs innovation in ciliate membrane trafficking. | as most of eukaryotic diversity lies in single-celled protists, they represent unique opportunities to ask questions about the balance of conservation and innovation in cell biological features. among free-living protists the ciliates offer ease of culturing, a rich array of experimental approaches, and versatile molecular tools, particularly in tetrahymena thermophila and paramecium tetraurelia. these attributes have been exploited by researchers to analyze a wealth of cellular structures in th ... | 2017 | 27696651 |
| antibody production using a ciliate generates unusual antibody glycoforms displaying enhanced cell-killing activity. | antibody glycosylation is a key parameter in the optimization of antibody therapeutics. here, we describe the production of the anti-cancer monoclonal antibody rituximab in the unicellular ciliate, tetrahymena thermophila. the resulting antibody demonstrated enhanced antibody-dependent cell-mediated cytotoxicity, which we attribute to unusual n-linked glycosylation. detailed chromatographic and mass spectrometric analysis revealed afucosylated, oligomannose-type glycans, which, as a whole, displ ... | 2017 | 27594301 |
| histone methyltransferase txr1 is required for both h3 and h3.3 lysine 27 methylation in the well-known ciliated protist tetrahymena thermophila. | dna replication elongation is tightly controlled by histone-modifying enzymes. our previous studies showed that the histone methytransferase txr1 (tetrahymena trithorax related protein 1) specifically catalyzes h3k27 monomethylation and affects dna replication elongation in tetrahymena thermophila. in this study, we investigated whether txr1 has a substrate preference to the canonical h3 over the replacement variant h3.3. we demonstrated by histone mutagenesis that k27q mutation in h3.3 further ... | 2017 | 27761696 |
| solution nmr structures of the c-domain of tetrahymena cytoskeletal protein tcb2 reveal distinct calcium-induced structural rearrangements. | tcb2 is a calcium-binding protein that localizes to the membrane-associated skeleton of the ciliated protozoan tetrahymena thermophila with hypothesized roles in ciliary movement, cell cortex signaling, and pronuclear exchange. tcb2 has also been implicated in a unique calcium-triggered, atp-independent type of contractility exhibited by filamentous networks isolated from the tetrahymena cytoskeleton. to gain insight into tcb2's structure-function relationship and contractile properties, we dete ... | 2016 | 27488393 |
| hlarp7 c-terminal domain contains an xrrm that binds the 3' hairpin of 7sk rna. | the 7sk small nuclear ribonucleoprotein (snrnp) sequesters and inactivates the positive transcription elongation factor b (p-tefb), an essential eukaryotic mrna transcription factor. the human la-related protein group 7 (hlarp7) is a constitutive component of the 7sk snrnp and localizes to the 3' terminus of the 7sk long noncoding rna. hlarp7, and in particular its c-terminal domain (ctd), is essential for 7sk rna stability and assembly with p-tefb. the hlarp7 n-terminal la module binds and prot ... | 2016 | 27679474 |
| introducing the concept of biocatalysis in the classroom: the conversion of cholesterol to provitamin d3. | biocatalysis is a fundamental concept in biotechnology. the topic integrates knowledge of several disciplines; therefore, it was included in the course "design and optimization of biological systems" which is offered in the biochemistry curricula. we selected the ciliate tetrahymena as an example of a eukaryotic system with potential for the biotransformation of sterol metabolites of industrial interest; in particular, we focused on the conversion of cholesterol to provitamin d3. the students wo ... | 2017 | 27666582 |
| low base-substitution mutation rate in the germline genome of the ciliate tetrahymena thermophil. | mutation is the ultimate source of all genetic variation and is, therefore, central to evolutionary change. previous work on paramecium tetraurelia found an unusually low germline base-substitution mutation rate in this ciliate. here, we tested the generality of this result among ciliates using tetrahymena thermophila. we sequenced the genomes of 10 lines of t. thermophila that had each undergone approximately 1,000 generations of mutation accumulation (ma). we applied an existing mutation-calli ... | 2016 | 27635054 |
| kinesin-14 is important for chromosome segregation during mitosis and meiosis in the ciliate tetrahymena thermophila. | ciliates such as tetrahymena thermophila have two distinct nuclei within one cell: the micronucleus that undergoes mitosis and meiosis and the macronucleus that undergoes amitosis, a type of nuclear division that does not involve a bipolar spindle, but still relies on intranuclear microtubules. ciliates provide an opportunity for the discovery of factors that specifically contribute to chromosome segregation based on a bipolar spindle, by identification of factors that affect the micronuclear bu ... | 2017 | 27595611 |
| enzymatic and chemical mapping of nucleosome distribution in purified micro- and macronuclei of the ciliated model organism, tetrahymena thermophila. | genomic distribution of the nucleosome, the basic unit of chromatin, contains important epigenetic information. to map nucleosome distribution in structurally and functionally differentiated micronucleus (mic) and macronucleus (mac) of the ciliate tetrahymena thermophila, we have purified mic and mac and performed micrococcal nuclease (mnase) digestion as well as hydroxyl radical cleavage. different factors that may affect mnase digestion were examined, to optimize mono-nucleosome production. mo ... | 2016 | 27568393 |
| novel ciliate lipases for enzyme replacement during exocrine pancreatic insufficiency. | exocrine pancreatic insufficiency caused by inflammation or pancreatic tumors results in nutrient malfunction by a lack of digestive enzymes and neutralization compounds. despite satisfactory clinical results with current enzyme therapies, a normalization of fat absorption in patients is rare. an individualized therapy is required that includes high dosage of enzymatic units, usage of enteric coating, and addition of gastric proton pump inhibitors. the key goal to improve this therapy is to iden ... | 2016 | 27518039 |
| dissecting relative contributions of cis- and trans-determinants to nucleosome distribution by comparing tetrahymena macronuclear and micronuclear chromatin. | the ciliate protozoan tetrahymena thermophila contains two types of structurally and functionally differentiated nuclei: the transcriptionally active somatic macronucleus (mac) and the transcriptionally silent germ-line micronucleus (mic). here, we demonstrate that mac features well-positioned nucleosomes downstream of transcription start sites and flanking splice sites. transcription-associated trans-determinants promote nucleosome positioning in mac. by contrast, nucleosomes in mic are dramati ... | 2016 | 27488188 |
| cooperation-mediated plasticity in dispersal and colonization. | kin selection theory predicts that costly cooperative behaviors evolve most readily when directed toward kin. dispersal plays a controversial role in the evolution of cooperation: dispersal decreases local population relatedness and thus opposes the evolution of cooperation, but limited dispersal increases kin competition and can negate the benefits of cooperation. theoretical work has suggested that plasticity of dispersal, where individuals can adjust their dispersal decisions according to the ... | 2016 | 27480245 |
| stress and protists: no life without stress. | we report a summary of the symposium "stress and protists: no life without stress", which was held in september 2015 on the vii european congress of protistology in partnership with the international society of protistologists (seville, spain). we present an overview on general comments and concepts on cellular stress which can be also applied to any protist. generally, various environmental stressors may induce similar cell responses in very different protists. two main topics are reported in t ... | 2016 | 27365178 |
| ionophoric polyphenols selectively bind cu(2+), display potent antioxidant and anti-amyloidogenic properties, and are non-toxic toward tetrahymena thermophila. | alzheimer's disease (ad) is the most common form of dementia affecting more than 28million people in the world. only symptomatic treatments are currently available. anticipated tri-fold increase of ad incidence in the next 50years has established the need to explore new possible treatments. accumulation of extracellular amyloid-β (aβ) plaques, intracellular tangles in the brain, and formation of reactive oxygen species (ros) are the major hallmarks of the disease. the active role of some metal i ... | 2016 | 27316544 |
| organic uv filters inhibit multixenobiotic resistance (mxr) activity in tetrahymena thermophila: investigations by the rhodamine 123 accumulation assay and molecular docking. | multixenobiotic resistance (mxr) transporters, which belong to atp-binding cassette (abc) family proteins, are present in living organisms as a first line of defense system against xenobiotics and environmental contaminants. the effects of six organic uv filters (4-methyl -benzylidene camphor, 4-mbc; benzophenone-3, bp-3; butyl methoxydibenzoyl-methane, bm-dbm; ethylhexyl methoxy cinnamate, ehmc; octocrylene, oc and homosalate, hms) on multixenobiotic resistance (mxr) in tetrahymena thermophila ... | 2016 | 27315091 |
| tetrahymena as a unicellular model eukaryote: genetic and genomic tools. | tetrahymena thermophila is a ciliate model organism whose study has led to important discoveries and insights into both conserved and divergent biological processes. in this review, we describe the tools for the use of tetrahymena as a model eukaryote, including an overview of its life cycle, orientation to its evolutionary roots, and methodological approaches to forward and reverse genetics. recent genomic tools have expanded tetrahymena's utility as a genetic model system. with the unique adva ... | 2016 | 27270699 |
| cyc17, a meiosis-specific cyclin, is essential for anaphase initiation and chromosome segregation in tetrahymena thermophila. | although the role of cyclins in controlling nuclear division is well established, their function in ciliate meiosis remains unknown. in ciliates, the cyclin family has undergone massive expansion which suggests that diverse cell cycle systems exist, and this warrants further investigation. a screen for cyclins in the model ciliate tetrahymena thermophila showed that there are 34 cyclins in this organism. only 1 cyclin, cyc17, contains the complete cyclin core and is specifically expressed during ... | 2016 | 27192402 |
| backbone and side-chain chemical shift assignments for the c-terminal domain of tcb2, a cytoskeletal calcium-binding protein from tetrahymena thermophila. | tcb2 is a putative calcium-binding protein from the membrane-associated cytoskeleton of the ciliated protozoan tetrahymena thermophila. it has been hypothesized to participate in several calcium-mediated processes in tetrahymena, including ciliary movement, cell cortex signaling, and pronuclear exchange. sequence analysis suggests that the protein belongs to the calmodulin family, with n- and c-terminal domains connected by a central linker, and two helix-loop-helix motifs in each domain. howeve ... | 2016 | 27155947 |
| netrin-1 peptide is a chemorepellent in tetrahymena thermophila. | netrin-1 is a highly conserved, pleiotropic signaling molecule that can serve as a neuronal chemorepellent during vertebrate development. in vertebrates, chemorepellent signaling is mediated through the tyrosine kinase, src-1, and the tyrosine phosphatase, shp-2. tetrahymena thermophila has been used as a model system for chemorepellent signaling because its avoidance response is easily characterized under a light microscope. our experiments showed that netrin-1 peptide is a chemorepellent in t. ... | 2016 | 27123011 |
| the key role of cyc2 during meiosis in tetrahymena thermophila. | meiotic recombination is carried out through a specialized pathway for the formation and repair of dna double-strand breaks (dsbs) made by the spo11 protein. the present study shed light on the functional role of cyclin, cyc2, in tetrahymena thermophila which has transcriptionally high expression level during meiosis process. knocking out the cyc2 gene results in arrest of meiotic conjugation process at 2.5-3.5 h after conjugation initiation, before the meiosis division starts, and in company wi ... | 2016 | 27008457 |
| hidden genetic variation in the germline genome of tetrahymena thermophila. | genome architecture varies greatly among eukaryotes. this diversity may profoundly affect the origin and maintenance of genetic variation within a population. ciliates are microbial eukaryotes with unusual genome features, such as the separation of germline and somatic genomes within a single cell and amitotic division. these features have previously been proposed to increase the rate of molecular evolution in these species. here, we assessed the fitness effects of genetic variation in the two g ... | 2016 | 26998689 |
| p28 dynein light chains and ciliary motility in tetrahymena thermophila. | dynein light chains are required for the assembly of axonemal dyneins into cilia and flagella. most organisms express a single p28 dynein light chain and four to nine one-headed inner arm dynein heavy chains. in contrast, tetrahymena encodes three p28 dynein light chain genes (p28a, p28b, and p28c) and 18 one-headed inner arm dynein heavy chains. in this article it is shown that mutations in p28a and p28b affected both beat frequency and waveform of cilia, while mutations in p28c affected only c ... | 2016 | 26994403 |
| dna double-strand break formation and repair in tetrahymena meiosis. | the molecular details of meiotic recombination have been determined for a small number of model organisms. from these studies, a general picture has emerged that shows that most, if not all, recombination is initiated by a dna double-strand break (dsb) that is repaired in a recombinogenic process using a homologous dna strand as a template. however, the details of recombination vary between organisms, and it is unknown which variant is representative of evolutionarily primordial meiosis or most ... | 2016 | 26899715 |
| tetrahymena basal bodies. | tetrahymena thermophila is a ciliate with hundreds of cilia primarily used for cellular motility. these cells propel themselves by generating hydrodynamic forces through coordinated ciliary beating. the coordination of cilia is ensured by the polarized organization of basal bodies (bbs), which exhibit remarkable structural and molecular conservation with bbs in other eukaryotes. during each cell cycle, massive bb assembly occurs and guarantees that future tetrahymena cells gain a full complement ... | 2015 | 26793300 |
| the oxidative stress response of myclobutanil and cyproconazole on tetrahymena thermophila. | using tetrahymena thermophila as experimental models, the oxidative stress of triazole fungicides myclobutanil (myc) and cyproconazole (cyp) was investigated. results showed that 24-h ec50 values for myc and cyp were 16.67 (13.37-19.65) and 20.44 (18.85-21.96) mg/l, respectively; 48-h ec50 values for myc and cyp were 14.31 (13.13-15.42) and 18.76 (17.09-20.31) mg/l, respectively. reactive oxygen species was significantly induced and cytotoxicity was caused by myc and cyp by increasing propidium ... | 2016 | 26724607 |