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Iqbal Aijaz, Gerald B Koudelka
Temperate phage encoded Shiga toxin (Stx) kills the bacterivorous predator, Tetrahymena thermophila, providing Stx+ Escherichia coli with a survival advantage over Stx- cells. Although bacterial death accompanies Stx release, since bacteria grow clonally the fitness benefits of predator killing accrue to the kin of the sacrificed organism, meaning Stx-mediated protist killing is a form of self-destructive cooperation. We show here that the fitness benefits of Stx production are not restricted to the kin of the phage-encoding bacteria...
April 19, 2018: MicrobiologyOpen
Jin Liu, Yuhao Dong, Nannan Wang, Shougang Li, Yuanyuan Yang, Yao Wang, Furqan Awan, Chengping Lu, Yongjie Liu
Persistence of Aeromonas hydrophila in aquatic environments is the principle cause of fish hemorrhagic septicemia. Protistan predation has been considered to be a strong driving force for the evolution of bacterial defense strategies. In this study, we investigated the adaptive traits of A. hydrophila NJ-35, a carp pathogenic strain, in response to Tetrahymena thermophila predation. After subculturing with Tetrahymena , over 70% of A. hydrophila colonies were small colony variants (SCVs). The SCVs displayed enhanced biofilm formation, adhesion, fitness, and resistance to bacteriophage infection and oxidative stress as compared to the non- Tetrahymena- exposed strains...
2018: Frontiers in Cellular and Infection Microbiology
Takahiko Akematsu, Andrew Findlay, Yasuhiro Fukuda, Ronald E Pearlman, Josef Loidl, Eduardo Orias, Eileen P Hamilton
6-methylpurine (6mp) is a toxic analog of adenine that inhibits RNA and protein synthesis and interferes with adenine salvage mediated by adenine phosphoribosyltransferase (APRTase). Mutants of the ciliated protist Tetrahymena thermophila that are resistant to 6mp were isolated in 1974, but the mechanism of resistance has remained unknown. To investigate 6mp resistance in T. thermophila , we created 6mp-resistant strains and identified a mutation in the APRTase genomic locus ( APRT1 ) that is responsible for 6mp resistance...
March 23, 2018: Genes
Alejandro Saettone, Jyoti Garg, Jean-Philippe Lambert, Syed Nabeel-Shah, Marcelo Ponce, Alyson Burtch, Cristina Thuppu Mudalige, Anne-Claude Gingras, Ronald E Pearlman, Jeffrey Fillingham
BACKGROUND: The chromatin remodelers of the SWI/SNF family are critical transcriptional regulators. Recognition of lysine acetylation through a bromodomain (BRD) component is key to SWI/SNF function; in most eukaryotes, this function is attributed to SNF2/Brg1. RESULTS: Using affinity purification coupled to mass spectrometry (AP-MS) we identified members of a SWI/SNF complex (SWI/SNFTt ) in Tetrahymena thermophila. SWI/SNFTt is composed of 11 proteins, Snf5Tt , Swi1Tt , Swi3Tt , Snf12Tt , Brg1Tt , two proteins with potential chromatin-interacting domains and four proteins without orthologs to SWI/SNF proteins in yeast or mammals...
March 9, 2018: Epigenetics & Chromatin
Marcel D O Pinheiro, Niels C Bols
For the first time, ciliates have been found to activate rather than inactivate a virus, chum salmon reovirus (CSV). Activation was seen as an increase in viral titre upon incubation of CSV at 22 °C with Tetrahymena canadenesis and two strains of T. thermophila: wild type (B1975) and a temperature conditional mutant for phagocytosis (NP1). The titer increase was not likely due to replication because CSV had no visible effects on the ciliates and no vertebrate virus has ever been shown unequivocally to replicate in ciliates...
March 5, 2018: Journal of Eukaryotic Microbiology
Janna Bednenko, Rian Harriman, Lore Mariën, Hai M Nguyen, Alka Agrawal, Ashot Papoyan, Yelena Bisharyan, Joanna Cardarelli, Donna Cassidy-Hanley, Ted Clark, Darlene Pedersen, Yasmina Abdiche, William Harriman, Bas van der Woning, Hans de Haard, Ellen Collarini, Heike Wulff, Paul Colussi
Identifying monoclonal antibodies that block human voltage-gated ion channels (VGICs) is a challenging endeavor exacerbated by difficulties in producing recombinant ion channel proteins in amounts that support drug discovery programs. We have developed a general strategy to address this challenge by combining high-level expression of recombinant VGICs in Tetrahymena thermophila with immunization of phylogenetically diverse species and unique screening tools that allow deep-mining for antibodies that could potentially bind functionally important regions of the protein...
March 1, 2018: MAbs
Takuji Ishikawa, Kenji Kikuchi
Understanding the behaviours of swimming microorganisms in various environments is important for understanding cell distribution and growth in nature and industry. However, cell behaviour in complex geometries is largely unknown. In this study, we used Tetrahymena thermophila as a model microorganism and experimentally investigated cell behaviour between two flat plates with a small angle. In this configuration, the geometry provided a 'dead end' line where the two flat plates made contact. The results showed that cells tended to escape from the dead end line more by hydrodynamics than by a biological reaction...
February 28, 2018: Proceedings. Biological Sciences
Usha P Kar, Himani Dey, Abdur Rahaman
Self-assembly on target membranes is one of the important properties of all dynamin family proteins. Drp6, a dynaminrelated protein in Tetrahymena, controls nuclear remodelling and undergoes cycles of assembly/disassembly on the nuclear envelope. To elucidate the mechanism of Drp6 function, we have characterized its biochemical and biophysical properties using size exclusion chromatography, chemical cross-linking and electron microscopy. The results demonstrate that Drp6 readily forms high-molecular-weight self-assembled structures as determined by size exclusion chromatography and chemical cross-linking...
March 2018: Journal of Biosciences
Daniela Sparvoli, Elisabeth Richardson, Hiroko Osakada, Xun Lan, Masaaki Iwamoto, Grant R Bowman, Cassandra Kontur, William A Bourland, Denis H Lynn, Jonathan K Pritchard, Tokuko Haraguchi, Joel B Dacks, Aaron P Turkewitz
In the endocytic pathway of animals, two related complexes, called CORVET (class C core vacuole/endosome transport) and HOPS (homotypic fusion and protein sorting), act as both tethers and fusion factors for early and late endosomes, respectively. Mutations in CORVET or HOPS lead to trafficking defects and contribute to human disease, including immune dysfunction. HOPS and CORVET are conserved throughout eukaryotes, but remarkably, in the ciliate Tetrahymena thermophila, the HOPS-specific subunits are absent, while CORVET-specific subunits have proliferated...
February 21, 2018: Current Biology: CB
Xiao Han, Haibo Xie, Yadong Wang, Chengtian Zhao
Radial spokes are structurally conserved, macromolecular complexes that are essential for the motility of 9 + 2 motile cilia. In Chlamydomonas species, mutations in radial spoke proteins result in ciliary motility defects. However, little is known about the function of radial spoke proteins during embryonic development. Here, we investigated the role of a novel radial spoke protein, leucine-rich repeat containing protein 23 (Lrrc23), during zebrafish embryonic development. Mutations in lrrc23 resulted in a selective otolith formation defect during early ear development...
February 22, 2018: FASEB Journal: Official Publication of the Federation of American Societies for Experimental Biology
Masaki Edamatsu
Mutational analyses of axonemal dyneins are useful for elucidating the molecular mechanism of ciliary motility. This study demonstrates a mutation system for characterizing lethal P-loop mutations in Tetrahymena outer arm dynein (Dyh3p). The viable DYH3-knockout (vKO-DYH3) cells isolated in this study enabled the examination of lethal mutations in P-loops 1 and 2. The P1 mutant dynein localized in the oral apparatus and the proximal region of the cilia, and the P2 mutant dynein localized only in the oral apparatus...
February 6, 2018: Biochemical and Biophysical Research Communications
Amanda K Mennie, Bettina A Moser, Toru M Nakamura
Telomerase is a reverse transcriptase complex that ensures stable maintenance of linear eukaryotic chromosome ends by overcoming the end replication problem, posed by the inability of replicative DNA polymerases to fully replicate linear DNA. The catalytic subunit TERT must be assembled properly with its telomerase RNA for telomerase to function, and studies in Tetrahymena have established that p65, a La-related protein 7 (LARP7) family protein, utilizes its C-terminal xRRM domain to promote assembly of the telomerase ribonucleoprotein (RNP) complex...
February 8, 2018: Nature Communications
Laura C Collopy, Tracy L Ware, Tomas Goncalves, Sunnvør Í Kongsstovu, Qian Yang, Hanna Amelina, Corinne Pinder, Ala Alenazi, Vera Moiseeva, Siân R Pearson, Christine A Armstrong, Kazunori Tomita
Understanding the intricacies of telomerase regulation is crucial due to the potential health benefits of modifying its activity. Telomerase is composed of an RNA component and reverse transcriptase. However, additional factors required during biogenesis vary between species. Here we have identified fission yeast Lar7 as a member of the conserved LARP7 family, which includes the Tetrahymena telomerase-binding protein p65 and human LARP7. We show that Lar7 has conserved RNA-recognition motifs, which bind telomerase RNA to protect it from exosomal degradation...
February 8, 2018: Nature Communications
Wei Miao, Jing Zhang, Guanxiong Yan, Miao Tian, Yang Ma, Jie Xiong
Evolutionarily conserved E2F family transcription factors regulate the cell cycle via controlling gene expression in a wide range of eukaryotes. We previously demonstrated that the meiosis-specific transcription factor E2fl1 had an important role in meiosis in the model ciliate Tetrahymena thermophila. Here, we report that expression of another E2F family transcription factor gene DPL2 correlates highly with that of E2FL1. Similar to e2fl1Δ cells, dpl2Δ cells undergo meiotic arrest prior to anaphase I, with the five chromosomes adopting an abnormal tandem arrangement...
February 8, 2018: Cell Cycle
Huanxin Zhou, Jing Xu, Wei Wang
Metallothioneins (MTs) are low-molecular-weight proteins with high Cys content and high metal-chelating ability. CdMT and CuMT subfamilies present different characteristics in Tetrahymena. To explore the effect of the cysteine arrangement and sequence length of MTs for binding different metal ions, MTT1, truncated MTT1 (TM1), MTT2, and truncated MTT2 (TM2) were expressed in E. coli. The half-maximal inhibiting concentrations (IC50) of Cd2+ and Cu+ for the recombinant strains were different. Furthermore, E. coli cells expressing MTT1 and TM1 exhibited higher accumulating ability for Cd2+ than cells expressing MTT2 and TM2...
February 5, 2018: Bioscience, Biotechnology, and Biochemistry
Ying Wang, Monika Mortimer, Chong Hyun Chang, Patricia A Holden
Robust evaluation of potential environmental and health risks of carbonaceous and boron nitride nanomaterials (NMs) is imperative. However, significant agglomeration of pristine carbonaceous and boron nitride NMs due to strong van der Waals forces renders them not suitable for direct toxicity testing in aqueous media. Here, the natural polysaccharide alginic acid (AA) was used as a nontoxic, environmentally relevant dispersant with defined composition to disperse seven types of carbonaceous and boron nitride NMs, including multiwall carbon nanotubes, graphene, boron nitride nanotubes, and hexagonal boron nitride flakes, with various physicochemical characteristics...
January 30, 2018: Nanomaterials
D H Lynn, F P Doerder, P L Gillis, R S Prosser
A ciliate protozoan was discovered whose presence coincided with a rapid decrease in the viability (i.e. ability to close valves) of glochidia of the freshwater mussel Lampsilis siliquoidea. Microscopic examination showed it to be a histophagous tetrahymenine ciliate. Small subunit (SSU) rRNA and cytochrome c oxidase subunit 1 (cox1) barcode sequences from cultured cells showed that it belongs to the same new species isolated from water samples as a free-living ciliate. Phylogenetic analyses place this new ciliate in the same clade with the macrostome species Tetrahymena paravorax, and we propose the name T...
January 31, 2018: Diseases of Aquatic Organisms
Chang Ho Lee, Seung Ryul Han, Seong-Wook Lee
Since the breakthrough discovery of catalytic RNAs (ribozymes) in the early 1980s, valuable ribozyme-based gene therapies have been developed for incurable diseases ranging from genetic disorders to viral infections and cancers. Ribozymes can be engineered and used to downregulate or repair pathogenic genes via RNA cleavage mediated by trans-cleaving ribozymes or repair and reprograming mediated by trans-splicing ribozymes, respectively. Uniquely, trans-splicing ribozymes can edit target RNAs via simultaneous destruction and repair (and/or reprograming) to yield the desired therapeutic RNAs, thus selectively inducing therapeutic gene activity in cells expressing the target RNAs...
January 31, 2018: Wiley Interdisciplinary Reviews. RNA
Lisa Siegmund, Michael Schweikert, Martin S Fischer, Johannes Wöstemeyer
Endosymbiotic interactions are frequently found in nature, especially in the group of protists. Even though many endosymbioses have been studied in detail, little is known about the mechanistic origins and physiological prerequisites of endosymbiont establishment. A logical step towards the development of endocytobiotic associations is evading digestion and escaping from the host's food vacuoles. Surface properties of bacteria are probably involved in these processes. Therefore, we chemically modified the surface of a transformant strain of Escherichia coli prior to feeding to Tetrahymena pyriformis...
January 27, 2018: Journal of Eukaryotic Microbiology
Mst Ara Gulshan, Md Motiar Rahman, Shigeyoshi Matsumura, Tsunehiko Higuchi, Naoki Umezawa, Yoshiya Ikawa
Group I intron ribozymes share common core elements that form a three-dimensional structure responsible for their catalytic activity. This core structure is unstable without assistance from additional factors that stabilize its tertiary structure. We examined biogenic triamine and tetraamine and also their fragments for their abilities to stabilize a structurally unstable group I ribozyme, ΔP5 ribozyme, derived from the Tetrahymena group I intron ribozyme by deleting its large activator module. Biogenic triamine (spermidine) and tetraamine (spermine) efficiently activated the ΔP5 ribozyme under conditions where the ribozyme was virtually inactive...
February 5, 2018: Biochemical and Biophysical Research Communications
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