Ciliated protozoan (Tetrahymena vorax), coloured scanning electron micrograph (SEM). Tetrahymena vorax is a fresh water, holotrichous, oligohymenophoran, ciliate. Shown here are 3 cells with nice ciliated pellicle surfaces. Tetrahymena are free-living ciliated protozoa that can switch from commensalistic to pathogenic modes of survival. They are common in freshwater ponds. Tetrahymena species are used as model organisms. Magnification: x260 when shortest axis printed at 25 millimetres. - Stock Image C032/0976
Large complex RNAs, like the Tetrahymena ribozyme, tend to have complex kinetic folding pathways with multiple intermediates. Are these intermediates required for folding, or are they the result of kinetic traps? One way to discriminate between these possibilities is to vary folding conditions such as temperature or ion concentration or to make mutations that may destabilize the folding intermediates and to see how these changes affect folding rates. In the present study, the effects of [Mg2+] and temperature on the rates of P3-P7 formation (kP3-P7) and folding to the catalytically active structure (koverall) were compared for the wild-type Tetrahymena ribozyme and the A183U mutant ribozyme. Reducing the [Mg2+] leads to an increase in the value of koverall and reveals the presence of an additional kinetic trap on the folding pathway of both ribozymes. Interestingly, this trap is stabilized by high [Mg2+]. Recent studies with the self-splicing Tetrahymena group I intron pre-RNA, from which the ...
TY - JOUR. T1 - Lectins and tetrahymena - A review. AU - Csaba, G.. PY - 2016/9/1. Y1 - 2016/9/1. N2 - The unicellular ciliate Tetrahymena is a complete organism, one of the most highly developed protozoans, which has specialized organelles performing each of the functions characteristic to the cells of higher ranked animals. It is also able to produce, store, and secrete hormones of higher ranked animals and also react to them. It produces lectins that can bind them and has functions, which are influenced by exogenous lectins. The review lists the observations on the relationship between lectins and Tetrahymena and try to construe them on the basis of the data, which are at our disposal. Considering the data, lectins can be used by Tetrahymena as materials for influencing conjugation, for stimulating hormone receptors, and by this, mimic the hormonal functions. Lectins can influence phagocytosis and movement of the cells as well as the cell division. As Tetrahymena can recognize both related ...
The elements of the Hippo pathway that are highly conserved and essential for Hippo signaling (the Hippo core) are: (1) upstream kinase Hippo/Mst, (2) downstream kinase Warts/Lats, and (3) Warts/Lats activator Mats/Mob1 (reviewed in Hilman and Gat 2011; Sebe-Pedros et al. 2012; Thompson and Sahai 2015; Meng et al. 2016). We show that a mutation in a Hippo/Mst kinase of Tetrahymena, CdaI, causes an anterior migration of the division plane, and defects in cytokinesis and nuclear divisions. The Hippo/Mst kinases phosphorylate themselves, the Warts/Lats kinase, and its activator Mats/Mob1 (reviewed in Meng et al. 2016). All three phosphorylations are needed to produce an active tertiary complex of Hippo/Mst-Warts/Lats-Mats/Mob1 (Gogl et al. 2015). Importantly, a knockdown of Mob1 in Tetrahymena generates a cell division phenotype that closely resembles that of cdaI-1 (Tavares et al. 2012), indicating that CdaI and Mob1 are in the same pathway, and that cdaI-1 is a loss-of-function mutation. ...
Tetrahymena hyperangularis ATCC ® 30351™ Designation: UI-7148c (10/IV) Isolation: freshwater Colorado, United States Isolation date: 1971
Tetrahymena hyperangularis ATCC ® 30351™ Designation: UI-7148c (10/IV) Isolation: freshwater Colorado, United States Isolation date: 1971
In addition to many high school level modules addressing a variety of biological concepts, ASSET has a new program designed to encourage motivated students to carry out independent research projects featuring the protozoan Tetrahymena as a model research organism.. Class use of standard ASSET high school modules can serve as an introduction to Tetrahymena as a research organism for exploring wide array of biological phenomena. Highly motivated students have an opportunity to subsequently engage in a teacher supervised independent research project using Tetrahymena as a research organism.. To provide classroom research opportunities for students at under-resourced schools, ASSET will supply the loan of needed materials and equipment free of charge.. ASSET is also interested in fostering independent student inquiry on topics related to science and society, now and throughout history. Teachers can utilize existing ASSET Science and Society modules available on our website to introduce their ...
In addition to many high school level modules addressing a variety of biological concepts, ASSET has a new program designed to encourage motivated students to carry out independent research projects featuring the protozoan Tetrahymena as a model research organism.. Class use of standard ASSET high school modules can serve as an introduction to Tetrahymena as a research organism for exploring wide array of biological phenomena. Highly motivated students have an opportunity to subsequently engage in a teacher supervised independent research project using Tetrahymena as a research organism.. To provide classroom research opportunities for students at under-resourced schools, ASSET will supply the loan of needed materials and equipment free of charge.. ASSET is also interested in fostering independent student inquiry on topics related to science and society, now and throughout history. Teachers can utilize existing ASSET Science and Society modules available on our website to introduce their ...
HI! Tetrahymena RNA self-splices and does it in a very specific series of steps. You find an RNA that self-splices in the same way. It also loops before splicing and the 5 end of the intron to the 3 end of the exon. You were able to figure out the six nucleotide sequence of the 3 end of the exon. Reading 5 to 3, what is the sequence of the base-pairing nucleotides on the intron starting at position #1? 5 TTTCGG 3 (No, this is a DNA sequence.) 5 GGCUUU 3 (No, this is the right sequence but it is in the wrong direction.) 5 GGCTTT 3 (No, this is a DNA sequence.) 5 UUUCGG 3 (That is correct.) G can hydrogen bond with C, and A can hydrogen bond with U. Reading 5 to 3 the complementary sequence is UUUCGG. You think that this base pairing is important for the self-splicing reaction. To prove this theory, you insert two Uracils into the intron and you find that self-splicing decreases dramatically. Other than deleting the 2 Us, how might you restore the self-splicing reaction to this RNA? ...
The Microbe collection is a diverse group of mAbs that recognize primarily surface components of prokaryotes including bacteria and viruses
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DExD/H-box proteins are a diverse class of proteins that are implicated in RNA and RNP remodeling. They have sequence homology to DNA helicases and share conserved ATPase domains, suggesting that they use the energy of ATP binding and hydrolysis to mediate conformational rearrangements in RNAs. In the past, the action of DExD/H-box proteins has been characterized primarily on simple model substrates such as small RNA duplexes. It is not known how DExD/H-box proteins manipulate structured RNA, what determines target specificity and what molecular events follow their action. Here, using the well-characterized Tetrahymena group I intron ribozyme, I performed kinetic and thermodynamic studies to understand the mechanism of CYT-19 and related DExD/Hbox proteins. CYT-19 has been shown previously to facilitate the folding of several group I and group II introns. I demonstrated that CYT-19 acts as a chaperone, accelerating the re-folding of a long-lived misfolded species of the Tetrahymena group I ...
Thymidine kinase is an enzyme involved in DNA precursor metabolism and DNA replication. The synthesis of this enzyme is highly regulated during the cell cycle and the activity of the enzyme is also regulated by feedback inhibition. Genes encoding thymidine kinase have been extremely useful as selectable markers for introducing DNA into a number of cells. In order to study cell cycle regulation of thymidine kinase, the gene which encodes this enzyme, as well as aspects of DNA replication in the ciliated protozoan Tetrahymena thermophila, we have purified thymidine kinase from Tetrahymena. Two forms of thymidine kinase with native molecular masses of 59 kDa and 80 kDa have been identified and purified 6800- and 4600-fold, respectively. The 59-kDa enzyme, a homodimer of 30-kDa subunits, has been purified to near homogeneity and polyclonal antibodies have been raised against the 30-kDa subunit. Serological studies indicate that the two enzymes are antigenically distinct. The antibody against the ...
Eesti Teadusinfosüsteem koondab informatsiooni teadus- ja arendusasutuste, teadlaste, teadusprojektide ning erinevate teadustegevuste tulemuste kohta.
Abstract: ATP-binding cassette transporters (ABCT) could generate multiple transcripts through alternative splicing (AS) in mammalian. Some AS introduced PTC (premature terminal codon)-containing isoforms of ABCT couple with NMD (nonsense-mediated mRNA decay) to regulate relevant functions. However, there are no similar reports in lower organisms. This paper focuses on the unicellular protozoa Tetrahymena thermophila, based on the RNA-seq data of Tetrahymena thermophila, identified two alternative splicing variants of gene ABCC10 (SV1 and SV2). The SV2 contained an intron retention event at the fifth intron, and this 49 bp-intron resulted in shift-frame and introduced PTC. Then, a knock-down Tetrahymena strain of gene UPF1 which is a key factor of NMD was constructed, and the expression levels of SV2 were performed using a real-time quantitative PCR. The results showed the expression levels of SV2 were up-regulated significantly in knock-down strain, indicating that SV2 was targeted by NMD, ...
The elaborate DCGs found in ciliates reflect complex sorting and assembly within the eukaryotic secretory pathway. Although substantial progress has been made in identifying DCG constituents in Tetrahymena and Paramecium, we do not yet understand how proteins are targeted to DCGs in ciliates, and indeed the targeting mechanisms are not yet clearly understood even in the much better studied animal systems (23). The multilayered DCG structures formed in some ciliate species raise the additional question of how protein sorting and organization within the DCGs are coordinated. Previous studies in Tetrahymena and Paramecium have focused on one family of proteins, the Tmps/Grls, and have demonstrated the importance of proteolytic processing for control of assembly although the details (including the proteases themselves) are not yet known (2, 8). However, the Grls/Tmps appear to constitute only the central expansible crystal in these DCGs, so other proteins must be responsible for the other ...
View Notes - Lecture8 from BIOC 100A at UCSC. 25 26 The hammerhead ribozyme (plant virus) Martick & Scott, Cell 2006 27 Group I intron ribozyme Golden et al, and cech Science (1998) 28 Acid-Base
With global warming acidifying oceanic and freshwater environments, the effects of pH have a significant impact on aquatic organisms (Heino et al., 2009). Salmon, a keystone species, rely heavily on ciliated protozoans as a food source (Orias et al., 2011; Pauly et al. 1996). The purpose of this experiment was to test the effects of pH on phagocytosis rate of Tetrahymena thermophila. This was done by exposing cells to ink-stained, pH-adjusted media and counting the number of ink-stained phagocytized vacuoles in five cells from three replicates of each treatment condition every 10 minutes during a two-hour feeding period. The mean rates determined were: 0.057 vpm at pH 5, 0.074 vpm at pH 6, and 0.074 vpm at pH 7. Using a one-way ANOVA, we obtained a test statistic (F) of 0.073 (Df =2) and a pvalue of 0.930 suggesting that the mean rate of phagocytosis does not differ between pH treatments (pH 5, pH 6, pH 7). Based on these results, we do not have sufficient evidence to support our alternative ...
Surprisingly, our ML analyses indicate that the distribution of mutational effects in T. thermophila is best approximated by the equal effects model (shape parameter, β → ∞). An alternative explanation is that the distribution of mutational effects is complex (e.g., a bimodal distribution including a high probability of slightly deleterious mutations and a second peak of moderately deleterious mutations) and not well approximated by any gamma distribution (Davies et al. 1999; Halligan and Keightley 2009). These hypotheses could be tested by repeating the multiple GE analysis for more MA lines, which would allow us to estimate the variance in mutational effects (Vs) directly.. In a survey of MA studies, Halligan and Keightley (2009) noted that the dominance of new mutations has been studied only in a handful of organisms and is not well understood even in those. Therefore, estimates in additional organisms are valuable. Our estimate of the average dominance coefficient of new mutations (h = ...
Utilization of temperature-sensitive mutants of Tetrahymena pyriformis affected in cell division or developmental pathway selection has permitted elucidation of causal dependencies interrelating micronuclear and macronuclear replication and division, oral development, and cytokinesis. In those mutants in which cell division is specifically blocked at restrictive temperatures, micronuclear division proceeds with somewhat accelerated periodicity but maintains normal coupling to predivision oral development. Macronuclear division is almost totally suppressed in an early acting mutant (mola) that prevents formation of the fission zone, and is variably affected in other mutants (such as mo3) that allow the fission zone to form but arrest constriction. However, macronuclear DNA synthesis can proceed for about four cycles in the nondividing mutant cells. A second class of mutants (psm) undergoes a switch of developmental pathway such that cells fail to enter division but instead repeatedly carry out an ...
Due to its central role in both evolutionary change and human disease, mutation has been the focus of intensive research. The probability that a spontaneous mut...
Adapted from Bozzone, M.D., and D.A. Martin 2000. An experimenal system to study phagocytosis. Pages 405-415, in Tested studies for laboratory teaching, Volume 21 (S.J. Karcher, Editor). Proceedings of the 21st Workshop/Conference of the Association for Biology Laboratory Education (ABLE). In this laboratory, you will study Tetrahymena phagocytosis. Phagocytosis is the process by which cells ingest large particles. Unicellular organisms such as Tetrahymena pyriformis carry out phagocytosis in order to obtain nutrients. During the process of phagocytosis, particles are internalized in an endocytic vesicle called a phagosome. The phagosome ultimately fuses with the lysosome so that nutrients can be broken down and used by the cell. In many multicellular organisms, only specialized cells are capable of phagocytosis. Instead of carrying out phagocytosis to obtain nutrients, human phagocytic cells called macrophages are capable of recognizing and engulfing pathogens or abnormal cells. In this lab, ...
Tetrahymena cells secrete a factor which inhibits RNA synthesis in vivo and in vitro. The factor is a relatively small peptide with a molecular weight between 300 and 1500 Daltons. Other, non-specific peptides in the broth medium or added to a chemically defined medium have a stimulatory effect on RNA synthesis in vivo and such peptides also stimulate the in vitro synthesis of RNA in a r-chromatin preparation. On the basis of these results we conclude that such extracellular small peptides compete with a specific factor which is part of the intracellular regulatory mechanism controlling the rate of RNA synthesis. The consequence of such competition is a high overproduction of ribosomal RNA in cells inoculated on peptide-rich broth media. ...
Two pathways for BB duplication have been identified (Marshall et al., 2001). In the more common, templated pathway, new BBs form in association with preexisting BBs. In the de novo pathway, BBs form in the absence of preexisting BBs. In Tetrahymena, most somatic BBs form once per cell cycle by a templated mechanism, (Allen, 1969) doubling the total number of somatic BBs each cell cycle. In contrast, to generate a new OA, a large number of BBs in the OP region is produced during a small portion of the cell cycle, either by rapid, repeated templating or, more likely, by a de novo pathway. A requirement for γ-tubulin in this rapid synthesis of new BBs likely explains why dividing cells without normal OP development appeared before other phenotypes were observed. We conclude that, as in Paramecium (Ruiz et al., 1999), γ-tubulin is required for BB duplication. Two lines of evidence support another novel finding of our study, that γ-tubulin is required for maintenance of mature BBs. First, the ...
Six new amphetamine-like molecules (2-[2,3-dihydro-4H-1,4-benzoxazine-4-yl]-1-methyl-2-[1-methyl-2-phenylethylamino] ethanamines) were synthesised and their physicochemical behaviour was studied. The log P values (index of lipophilicity) of the derivatives were calculated according to Rekkers fragmental system. One derivative representative of each series (C-5508 and C-5512) was selected, and their biological effects on the phagocytic ability of the protozoan, Tetrahymena pyriformis, were studied as a basic functional test for an amphetamine-like action. Furthermore, the action of both derivatives when administered concomitantly with haloperidol was also investigated. The data indicate that both derivatives significantly increased the phagocytic ability of the protozoan (p < 0.001), presumably via an alternative pathway to that of one of the dopamine monoaminergic pools. The administration of haloperidol significantly suppressed phagocytosis (p < 0.001). However, cultures exposed to the ...
Tetrahymena thermophila is a freshwater unicellular ciliated protozoan related to Paramecium. >Tetrahymena thermophila is a freshwater unicellular ciliated protozoan related to Paramecium. ...
Cultures of Tetrahymena pyriformis, T. hegewishi and T. malaccensis have been studied with regard to control of cell volume and cellular dry weight. Cell volume was measured on cells suspended in 0.9% sodium chloride + 0.1% sodium azide using a Multi
View Stock Photo of Predation Among Protozoans A Dileptus Consuming A Tetrahymena Dileptus Is A Predatory Protozoan Sem. Find premium, high-resolution photos at Getty Images.
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 effe
25. Tsuchihashi, Z., Khosla, M., Herschlag, D. (1993) Science 262, 99-102. Protein Enhancement of Hammerhead Ribozyme Catalysis. PMID: 7692597. (Medline) (PDF File) 24. McConnell, T.S., Cech, T.R., Herschlag, D. (1993) Proc. Natl. Acad. Sci. U.S.A. 90, 8362-8366. Guanosine Binding to the Tetrahymena Ribozyme: Thermodynamic Coupling with Oligonucleotide Binding. PMCID: PMC47356. (Medline) (PDF File). 23. Herschlag, D., Johnson, F.B. (1993) Genes & Development 7, 173-179. Synergism in Transcriptional Activation: A Kinetic View. PMID: 8436289. (Medline) (PDF File). The above publications are as an Independent Investigator (7/92-Present). 22. Labow, B., Herschlag, D., Jencks, W.P. (1993) Biochemistry 32, 8737-8741. Catalysis of the Hydrolysis of Phosphorylated Pyridines by Alkaline Phosphatase Has Little or No Dependence on the pKa of the Leaving Group. PMID: 8395879. (Medline) (PDF File). 21. Herschlag, D., Eckstein, F., Cech, T.R. (1993) Biochemistry 32, 8312-3221. The Importance of Being Ribose ...
25. Tsuchihashi, Z., Khosla, M., Herschlag, D. (1993) Science 262, 99-102. Protein Enhancement of Hammerhead Ribozyme Catalysis. PMID: 7692597. (Medline) (PDF File) 24. McConnell, T.S., Cech, T.R., Herschlag, D. (1993) Proc. Natl. Acad. Sci. U.S.A. 90, 8362-8366. Guanosine Binding to the Tetrahymena Ribozyme: Thermodynamic Coupling with Oligonucleotide Binding. PMCID: PMC47356. (Medline) (PDF File). 23. Herschlag, D., Johnson, F.B. (1993) Genes & Development 7, 173-179. Synergism in Transcriptional Activation: A Kinetic View. PMID: 8436289. (Medline) (PDF File). The above publications are as an Independent Investigator (7/92-Present). 22. Labow, B., Herschlag, D., Jencks, W.P. (1993) Biochemistry 32, 8737-8741. Catalysis of the Hydrolysis of Phosphorylated Pyridines by Alkaline Phosphatase Has Little or No Dependence on the pKa of the Leaving Group. PMID: 8395879. (Medline) (PDF File). 21. Herschlag, D., Eckstein, F., Cech, T.R. (1993) Biochemistry 32, 8312-3221. The Importance of Being Ribose ...
Proceedings of the 9. Congress of The Nordic Society for Cell Biology : Papers presented at the Congress of The Nordic Society for Cell biology held in Odense, Denmark August 11-13, ...
Tytuł projektu: Rozbudowa i przekształcenie bibliograficznej bazy danych AGRO w bazę bibliograficzno-abstraktową z wykorzystaniem oprogramowania YADDA. Nr umowy: POIG 02.03.02-00-031/09 (okres realizacji 2009-2013 ...
Hamilton, EP., Kapusta, A., Huvos, PE., Bidwell, SL., Zafar, N., Tang, H., Hadjithomas, M., Krishnakumar, V., Badger, JH., Caler, EV., Russ, C., Zeng, Q., Fan, L., Levin, JZ., Shea, T., Young, SK., Hegarty, R., Daza, R., Gujja, S., Wortman, JR., Birren, BW., Nusbaum, C., Thomas, J., Carey, CM., Pritham, EJ., Feschotte, C., Noto, T., Mochizuki, K., Papazyan, R., Taverna, SD., Dear, PH., Cassidy-Hanley, DM., Xiong, J., Miao, W., Orias, E., Coyne, RS. (2016). Structure of the germline genome of Tetrahymena thermophila and relationship to the massively rearranged somatic genome. Elife. 5 (abstract ...
The wide, but scattered distribution of group I introns in nature is a result of two processes; the vertical inheritance of introns with or without losses, and the occasional transfer of introns across species barriers. Reversal of the group I intron
The cell cortex (or pellicle) of "Tetrahymena" is composed of three closely associated layers: the cell membrane, the alveolar sacs, and the epiplasm. The epiplasm is the innermost layer of the cortex and is thought to ...
DNA damage caused by ultraviolet (UV) irradiation can occur in various states of chromatin organization and is repaired mainly by nucleotide excision repair (NER). The ciliated protozoan Tetrahymena thermophila contains a transcriptionally silent germline micronucleus (MIC), where chromatin is relatively tight, and a transcriptionally active somatic macronucleus (MAC), where chromatin is relatively loose. This unique characteristic provides an opportunity to assess the effects of DNA repair at different states of chromatin organization. Genomic rearrangement occurs as portions of the MIC DNA are excised at specific internal eliminated sequences (IES) and removed prior to development of the new MAC DNA, and telomeres are added at chromosome breakage sites (CBS). The aim of this research was to investigate NER in T. thermophila by creating an assay that utilizes this genomic rearrangement to detect sites of DNA damage. An assay utilizing quantitative PCR (qPCR) and primers specific for the CBS locus Tt819
TY - JOUR. T1 - Hsp40 is involved in cilia regeneration in sea urchin embryos. AU - Gianguzza, Fabrizio. AU - Ragusa, Maria Antonietta. AU - Casano, Caterina. AU - Roccheri, Maria Carmela. AU - Maenza, Luigia. AU - Casano, Caterina. AU - Gianguzza, Fabrizio. AU - Di Giorgi, Rossana. AU - Roccheri, Maria C.. AU - Ragusa, Maria A.. PY - 2003. Y1 - 2003. N2 - In a previous paper we demonstrated that, in Paracentrotus lividus embryos, deciliation represents a specific kind of stress that induces an increase in the levels of an acidic protein of about 40 kD (p40). Here we report that deciliation also induces an increase in Hsp40 chaperone levels and enhancement of its ectodermal localization. We suggest that Hsp40 might play a chaperoning role in cilia regeneration.. AB - In a previous paper we demonstrated that, in Paracentrotus lividus embryos, deciliation represents a specific kind of stress that induces an increase in the levels of an acidic protein of about 40 kD (p40). Here we report that ...
TY - JOUR. T1 - Kin5 knockdown in Tetrahymena thermophila using RNAi blocks cargo transport of Gef1. AU - Awan, Aashir. AU - Bell, Aaron J.. AU - Satir, Peter. PY - 2009/3/17. Y1 - 2009/3/17. N2 - A critical process that builds and maintains the eukaryotic cilium is intraflagellar transport (IFT). This process utilizes members of the kinesin-2 superfamily to transport cargo into the cilium (anterograde transport) and a dynein motor for the retrograde traffic. Using a novel RNAi knockdown method, we have analyzed the function of the homodimeric IFT kinesin-2, Kin5, in Tetrahymena ciliary transport. In RNAi transformants, Kin5 was severely downregulated and disappeared from the cilia, but cilia did not resorb, although tip structure was affected. After deciliation of the knockdown cell, cilia regrew and cells swam, which suggested that Kin5 is not responsible for the trafficking of axonemal precursors to build the cilium, but could be transporting molecules that act in ciliary signal transduction, ...
The evaluation of molecules that have potentially bioactive significance is an expanding field, but current screening assays are expensive and time consuming. Mammalian cell-based assays require aseptic techniques, complex media and long generation times. This thesis reports on an assay that incorporates Tetrahymena phagocytic ingestion and flow cytometry to evaluate several potentially bioactive molecules. Several factors that influenced optimal and reproducible results were analyzed. Seven potentially bioactive molecules (serotonin, norepinephrine, dopamine, morphine, colchicine, mexiletine and procainamide) were evaluated to determine their effect on phagocytosis by Tetrahymena. Assay results indicated that the phagocytic rate was unaffected by serotonin, norepinephrine, dopamine, and morphine but inhibited by colchicine, mexiletine and procainamide. The analysis of the data indicated that acclimation time, temperature, cell concentration, and cell wash media affected assay consistency. This
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-calling pipeline and developed a new probabilistic mutation detection approach that directly models the design of an MA experiment and accommodates the noise introduced by mismapped reads. Our probabilistic mutation-calling method provides a straightforward way of estimating the number of sites at which a mutation could have been called if one was present, providing the denominator for our mutation rate calculations. From these methods, we find that T. thermophila has a germline base-substitution mutation rate ...
Pellicular fragments were isolated from ethanol-fixed cells of the holotrichous ciliate Tetrahymena pyriformis by the action of digitonin. The isolated pellicles were further fragmented and the basal bodies of the cilia isolated from them by three methods. The preparations, examined in the electron microscope as embedded sections or negatively stained samples, consisted mainly of somewhat deformed pellicular material, the bulk of which was basal body. DNA was determined by the diphenylamine method and by reaction with DNase, and RNA, by the orcinol method. Nucleic acids were isolated by phenol extraction and analyzed spectrophotometrically and by reaction with RNase. The assays indicated 1.2 to 2.6 per cent RNA, similar to previously published work, but only 0.0 to 1.0 per cent DNA, near enough the sensitivity limits to render the presence of DNA in the preparations uncertain. Although the isolation procedure removed nuclear contents and ribosomes, the nucleic acids could still be a residual ...
TY - JOUR. T1 - Chemotactic response of unicellular tetrahymena to a leukocyte attractant peptide and its repellent derivate. T2 - evolutionary conclusions.. AU - Kõhidai, László. AU - Kovács, Péter. AU - Csaba, György. PY - 1994/2/1. Y1 - 1994/2/1. N2 - Chemotactic properties of the leukocyte chemoattractant N-formyl-Norleucine-Leucine-Phenylalanine (NLP) and its antagonist N-t-BOC-Norleucine-Leucine-Phenylalanine (BOC-NLP) were investigated in unicellular Tetrahymena pyriformis cells. NLP express its attractant character in a two-peak profile of concentration course (maximum at 10-8-10-7 M and 10-11 M) while BOC-NLP has a constant repellent character (maximum at 10-12 M). The observed homology of action concurs with our theory about the wide evolutionary background of signal molecules and receptors.. AB - Chemotactic properties of the leukocyte chemoattractant N-formyl-Norleucine-Leucine-Phenylalanine (NLP) and its antagonist N-t-BOC-Norleucine-Leucine-Phenylalanine (BOC-NLP) were ...
In the present study, two new MT (MTT-5 in T. thermophila and MT-2 in T. pyriformis) gene isoforms have been cloned and characterized. The transcriptional activity of MTT-2 and MTT-5 towards heavy metals (cadmium, copper and zinc), was evaluated. Results showed that the three metals induced different MTT-2-mRNA and MTT-5-mRNA levels. Furthermore, using the coding sequence of nrk2-GFP gene as a reporter, I found that the upstream region of MTT5 induced nrk2-GFP protein expression. The fluorescence was present in the basal bodies and at the tips of cilia within transformed cells. These results have substantially contributed to demonstrate the suitability of free-living protozoan in studies of cell tolerance to heavy metals, and they have validated the use of Tetrahymena as a model system to determine ecotoxicological risk. To date, only a limited number of inducible promoters for driving high-level gene expression in T. thermophila has been described. Furthermore, little is known about the ...
Scott, D G. and Daniel, C W., "Filaments in the division furrow of mouse mammary cells." (1970). Subject Strain Bibliography 1970. 1754 ...
Eisen JA, Coyne RS, Wu M, Wu D, Thiagarajan M, Wortman JR, Badger JH, Ren Q, Amedeo P, Jones KM, Tallon LJ, Delcher AL, Salzberg SL, Silva JC, Haas BJ, Majoros WH, Farzad M, Carlton JM, Smith RK Jr, Garg J, Pearlman RE, Karrer KM, Sun L, Manning G, Elde NC, Turkewitz AP, Asai DJ, Wilkes DE, Wang Y, Cai H, Collins K, Stewart BA, Lee SR, Wilamowska K, Weinberg Z, Ruzzo WL, Wloga D, Gaertig J, Frankel J, Tsao CC, Gorovsky MA, Keeling PJ, Waller RF, Patron NJ, Cherry JM, Stover NA, Krieger CJ, del Toro C, Ryder HF, Williamson SC, Barbeau RA, Hamilton EP, Orias E. Macronuclear genome sequence of the ciliate Tetrahymena thermophila, a model eukaryote. PLoS Biol. 2006 Sep;4(9):e286. PubMedhttp://bobcat.genomecenter.ucdavis.edu/mediawiki/images/0/08/Pdf-logo.jpg[Eisen-2006] ...
RNA enzymes or ribozymes can act as endoribonucleases, catalyzing the cleavage of RNA molecules with a sequence specificity of cleavage greater than that of known ribonucleases and approaching that of the DNA restriction endonucleases, thus serving as RNA sequence specific endoribonucleases. An example is a shortened form of the self-splicing ribonsomal RNA intervening sequence of Tetrahymena (L-19 IVS RNA). Site-specific mutagenesis of the enzyme active site of the L-19 IVS RNA alters the substrate sequence specificity in a predictable manner, allowing a set of sequence-specific endoribonucleases to be synthesized. Varying conditions allow the ribozyme to act as a polymerase (nucleotidyltransferase), a dephosphorylase (acid phosphatase or phosphotransferase) or a sequence-specific endoribonuclease.
A composite of cross sections through the cilium-basal body complex extending from the cilium to the transition zone between the cilium and basal body...
The contractile vacuole, an organelle used by many protists for osmoregulation of water and some ions, such as calcium, is connected to the cell surfa...
Tetrahymena thermophila is one of a handful of "model organisms" that also includes yeast, fruit flies, nematode worms, zebrafish and mice. Like the other model organisms, it is relatively easy to keep in the laboratory, and lends itself well to experimental manipulation and analysis. Tetrahymena has been an important contributor for information on cell motility-especially cilia (pictured here in red) and related proteins (one of which is pictured here in green). It has also been involved in at least two Nobel Prizes: the first, in 1989, for the discovery of ribozymes, and the second, in 2009, for the discovery of the structure of telomeres and the roles of telomere shortening in cellular ageing (senescence) and chromosomal instability. Technical Details ...