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Brody Holohan, Wanil Kim, Tsung-Po Lai, Hirotoshi Hoshiyama, Ning Zhang, Anas M Alazami, Woodring E Wright, M Stephen Meyn, Fowzan S Alkuraya, Jerry W Shay
BACKGROUND: Loss of function in genes required for telomere maintenance result in disorders known as telomeropathies, which are characterized by a pattern of symptoms including generalized and specific lymphocytopenias as well as very short telomere length and disease anticipation. METHODS: Because human LARP7 is the most likely ortholog of the Tetrahymena p65 protein, which is required for telomerase activity in that organism, we investigated the effects of LARP7 silencing in human cells as well as in two distinct families with Alazami syndrome (loss of function of LARP7)...
October 17, 2016: BMC Genomics
Xiaolu Zhao, Yuanyuan Wang, Yurui Wang, Yifan Liu, Shan Gao
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 aggravated the replication stress phenotype of K27Q mutation in canonical H3, supporting H3...
October 17, 2016: Science China. Life Sciences
Ewa Waclawek, Ewa Joachimiak, Malgorzata Hanna Hall, Hanna Fabczak, Dorota Wloga
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 C. elegans, Xenopus and mammals indicate that katanin is regulated at multiple levels including transcription, posttranslational modifications (of both katanin and microtubules) and degradation...
October 11, 2016: Molecular Microbiology
Abhigyan Sengupta, Hsuan-Lei Sung, David J Nesbitt
In light of the current models for an early RNA-based universe, the potential influence of simple amino acids on tertiary folding of ribozymal RNA into biochemically competent structures is speculated to be of significant evolutionary importance. In the present work, the folding-unfolding kinetics of a ubiquitous tertiary interaction motif, the GAAA tetraloop-tetraloop receptor (TL-TLR), is investigated by single-molecule fluorescence resonance energy transfer spectroscopy in the presence of natural amino acids both with (e...
October 10, 2016: Journal of Physical Chemistry. B
Sabrice Guerrier, Helmut Plattner, Elizabeth H Richardson, Joel B Dacks, Aaron P Turkewitz
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 these large and complex cells...
October 3, 2016: Traffic
Catherine D Eichhorn, Rahul Chug, Juli Feigon
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 protects the 3' end from degradation, but the structural and functional role of its CTD is unclear...
September 26, 2016: Nucleic Acids Research
Karel Dieguez-Santana, Hai Pham-The, Pedro J Villegas-Aguilar, Huong Le-Thi-Thu, Juan A Castillo-Garit, Gerardo M Casañola-Martin
In this article, the modeling of inhibitory grown activity against Tetrahymena pyriformis is described. The 0-2D Dragon descriptors based on structural aspects to gain some knowledge of factors influencing aquatic toxicity are mainly used. Besides, it is done by some enlarged data of phenol derivatives described for the first time and composed of 358 chemicals. It overcomes the previous datasets with about one hundred compounds. Moreover, the results of the model evaluation by the parameters in the training, prediction and validation give adequate results comparable with those of the previous works...
December 2016: Chemosphere
Belén M De Luca, Clara B Nudel, Rodrigo H Gonzalez, Alejandro D Nusblat
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 work with wild type and recombinant strains and learn how sterol pathways could be modified to obtain diverse sterol moieties...
September 26, 2016: Biochemistry and Molecular Biology Education
Hongan Long, David J Winter, Allan Y-C Chang, Way Sung, Steven H Wu, Mariel Balboa, Ricardo B R Azevedo, Reed A Cartwright, Michael Lynch, Rebecca A Zufall
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...
September 15, 2016: Genome Biology and Evolution
Andrzej Kaczanowski, Clifford F Brunk, Stanislaw L Kazubski
The histophagous ciliate Tetrahymena rostrata was found as a parasite in the renal organs of the land snails Zonitoides nitidus and Cochlicopa lubrica. A starvation medium induced encystment, meiosis, autogamy, and development of new macronuclei. The cell division rate declined linearly with number of divisions from the last autogamy until senescence. The senescing strains were rejuvenated by further encystment-induced autogamy. It is expected, that these processes contribute to genetic variability among the local, small, and isolated T...
November 2016: Protist
Gianna Pitsch, Lubomír Adamec, Sebastian Dirren, Frank Nitsche, Karel Šimek, Dagmara Sirová, Thomas Posch
The genus Tetrahymena (Ciliophora, Oligohymenophorea) probably represents the best studied ciliate genus. At present, more than forty species have been described. All are colorless, i.e. they do not harbor symbiotic algae, and as aerobes they need at least microaerobic habitats. Here we present the morphological and molecular description of the first green representative, Tetrahymena utriculariae n. sp., living in symbiosis with endosymbiotic algae identified as Micractinium sp. (Chlorophyta). The full life cycle of the ciliate species is documented, including trophonts and theronts, conjugating cells, resting cysts and dividers...
September 10, 2016: Journal of Eukaryotic Microbiology
Karel Šimek, Gianna Pitsch, Michaela M Salcher, Dagmara Sirová, Tanja Shabarová, Lubomir Adamec, Thomas Posch
Trap fluid of aquatic carnivorous plants of the genus Utricularia hosts specific microbiomes consisting of commensal pro- and eukaryotes of largely unknown ecology. We examined the characteristics and dynamics of bacteria and the three dominant eukaryotes, i.e., the algae-bearing ciliate Tetrahymena utriculariae (Ciliophora), a green flagellate Euglena agilis (Euglenophyta), and the alga Scenedesmus alternans (Chlorophyta), associated with the traps of Utricularia reflexa. Our study focused on ecological traits and life strategies of the highly abundant ciliate whose biomass by far exceeds that of other eukaryotes and bacteria independent of the trap age...
September 10, 2016: Journal of Eukaryotic Microbiology
Tanima Biswas, Probir Kumar Bandyopadhyay
Several protozoan parasites have been found infecting the edible oysters, hence deteriorating the meat quality. Protozoan parasites such as, Tetrahymena rostrata and Callimastix equi infested the edible oyster in Sundarbans region, West Bengal, India, are first record from this region. Due to filter feeding habit of the organisms, oysters provides excellent ecological services in regard to efficient cleaning of infectious agents from surrounding water as a potential measure to improve water quality. However, these environmental benefits are associated with public heath risks from contaminated oysters intended for human consumption...
September 2016: Journal of Parasitic Diseases: Official Organ of the Indian Society for Parasitology
A Nematollahi, S Jaberi, J Ashrafi Helan, N Sheikhzadeh
During March 2012 through February 2013, 100 freshwater ornamental fishes in 22 species from some aquarium fish shops were examined. Specimens were dissected and tissue samples consisted of liver, kidney, spleen, heart, intestine, ovary, brain and eye were fixed in 10 % buffered formalin and sections were provided and stained with hematoxylin and eosin, Periodic Acid-Schiff, Giemsa and acid-fast staining (Ziehl-Neelsen). At present study six species of protozoans consisting of Eimeria spp. Cryptosporidium spp...
September 2016: Journal of Parasitic Diseases: Official Organ of the Indian Society for Parasitology
Vladyslav S Bondarenko, Mikhail S Gelfand
A typical eukaryotic gene is comprised of alternating stretches of regions, exons and introns, retained in and spliced out a mature mRNA, respectively. Although the length of introns may vary substantially among organisms, a large fraction of genes contains short introns in many species. Notably, some Ciliates (Paramecium and Nyctotherus) possess only ultra-short introns, around 25 bp long. In Paramecium, ultra-short introns with length divisible by three (3n) are under strong evolutionary pressure and have a high frequency of in-frame stop codons, which, in the case of intron retention, cause premature termination of mRNA translation and consequent degradation of the mis-spliced mRNA by the nonsense-mediated decay mechanism...
2016: PloS One
Yasuharu Kushida, Masak Takaine, Kentaro Nakano, Toshiro Sugai, Krishna Kumar Vasudevan, Mayukh Guha, Yu-Yang Jiang, Jacek Gaertig, Osamu Numata
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 but not the macronuclear division...
September 6, 2016: Journal of Eukaryotic Microbiology
Jenny Calow, Anna-Janina Behrens, Sonja Mader, Ulrike Bockau, Weston B Struwe, David J Harvey, Kai U Cormann, Marc M Nowaczyk, Karin Loser, Daniel Schinor, Marcus W W Hartmann, Max Crispin
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, displayed isomeric structures that deviate from the typical human counterparts, but whose branches were equivalent to fragments of metabolic intermediates observed in human glycoproteins...
September 3, 2016: MAbs
Jonathon O Pritchard, Alice H M Porter, David J S Montagnes
We planned to develop predator-prey models using Paramecium and yeast, but they have not been empirically examined since work by Gause in the 1930s. Therefore, we evaluated if Paramecium aurelia ingests and grows on eight yeasts. Recognising that it ingested yeasts but could not grow, we assessed if it might grow on other yeasts, by empirically parameterising a predator-prey model that relies on ingestion, not growth. Simulations were compared to P. aurelia-yeast time-series data, from Gause. We hypothesised that if the model simulated predator-prey dynamics that mimicked the original data, then possibly P...
September 2016: Journal of Eukaryotic Microbiology
Katerina Yale, Alan J Tackett, Monica Neuman, Emily Bulley, Brian T Chait, Emily Wiley
The evolutionarily conserved proteins related to heterochromatin protein 1 (HP1), originally described in Drosophila, are well known for their roles in heterochromatin assembly and gene silencing. Targeting of HP1 proteins to specific chromatin locales is mediated, at least in part, by the HP1 chromodomain, which binds to histone H3 methylated at lysine 9 that marks condensed regions of the genome. Mechanisms that regulate HP1 targeting are emerging from studies with yeast and metazoans and point to roles for posttranslational modifications...
July 2016: MSphere
Juan A Castillo-Garit, Concepción Abad, Gerardo M Casañola-Martin, Stephen Jones-Barigye, Francisco Torrens, Amparo Torreblanca
Atom-based quadratic indices are used to obtain quantitative structure-activity relationship (QSAR) models for the prediction of aquatic toxicity. Our models agree with the principles required by the OECD for QSAR models to regulatory purposes. The database employed consists of 392 substituted benzenes with toxicity values measured in Tetrahymena pyriformis (defined endpoint), was divided using cluster analysis in two series (training and test sets). We obtain (with an unambiguous algorithm) two good multiple linear regression models for non-stochastic (R2=0...
August 3, 2016: Current Pharmaceutical Design
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