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Ziyadi S, Iddar A, Kabine M, El Mzibri M, Moutaouakkil A. Changes in Growth, Morphology, and Physiology of Tetrahymena pyriformis Exposed to Continuous Cesium-137 and Cobalt-60 Gamma-Radiation. Curr Microbiol 2022; 79:61. [PMID: 34982197 DOI: 10.1007/s00284-021-02684-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 10/01/2021] [Indexed: 12/15/2022]
Abstract
This study investigated the effects of gamma-radiation on Tetrahymena pyriformis. The experimental approach consists of exposing T. pyriformis growing in presence of Cesium-137 (137Cs) at dose rates of 1, 2, 4, and 6 cGy h-1 and Cobalt-60 (60Co) at dose rates of 8, 10, 15, and 20 cGy h-1. The radiation doses effects on growth, morphology, some metabolic enzymes, and reactive oxygen species (ROS) markers have been evaluated. When cells were growing in irradiating conditions at dose rates beyond 4 cGy h-1, a decreasing of cells and generation numbers with a prolongation of generation time and a change of morphological aspect with rounding-off of cells were observed compared to the control. The 50%-inhibitory dose (ID50) for radiation was estimated at 1568.72 ± 158.45 cGy. The gamma-radiation at dose rates more than 6 cGy h-1, affected both glyceraldehyde 3-phosphate dehydrogenase and succinate dehydrogenase by inhibiting their activities. All of these effects were more pronounced when cells were irradiated at the dose rate of 20 cGy h-1 using 60Co source. For ROS markers generated by gamma-radiation in T. pyriformis, the results showed an increase of the lipid peroxidation in cells grown in presence of gamma-radiation at dose rates more than 6 cGy h-1 and an enhancement in catalase and superoxide dismutase activities from the dose rate of 1 cGy h-1. These encouraging results suggested the use of T. pyriformis as a unicellular model cell to investigate other aspects of the response to ionizing radiation.
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Affiliation(s)
- Soukaina Ziyadi
- Biotechnology and Biomolecules Engineering Unit, National Center for Nuclear Energy, Science and Technology (CNESTEN), BP. 1382 R.P., 10001, Rabat, Morocco.,Health and Environment Laboratory, Faculty of Sciences Aïn-Chock, Hassan II University, Km 8 Route d'El Jadida, BP 5366 Mâarif, 20100, Casablanca, Morocco
| | - Abdelghani Iddar
- Biotechnology and Biomolecules Engineering Unit, National Center for Nuclear Energy, Science and Technology (CNESTEN), BP. 1382 R.P., 10001, Rabat, Morocco
| | - Mostafa Kabine
- Health and Environment Laboratory, Faculty of Sciences Aïn-Chock, Hassan II University, Km 8 Route d'El Jadida, BP 5366 Mâarif, 20100, Casablanca, Morocco
| | - Mohammed El Mzibri
- Biotechnology and Biomolecules Engineering Unit, National Center for Nuclear Energy, Science and Technology (CNESTEN), BP. 1382 R.P., 10001, Rabat, Morocco
| | - Adnane Moutaouakkil
- Biotechnology and Biomolecules Engineering Unit, National Center for Nuclear Energy, Science and Technology (CNESTEN), BP. 1382 R.P., 10001, Rabat, Morocco.
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Rhind N. Cell Size Control via an Unstable Accumulating Activator and the Phenomenon of Excess Mitotic Delay. Bioessays 2017; 40. [PMID: 29283187 DOI: 10.1002/bies.201700184] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 11/30/2017] [Indexed: 01/21/2023]
Abstract
Unstable Accumulating Activator models for cellular size control propose an activator that accumulates in a size-dependent manner and triggers cell cycle progression once it has reached a certain threshold. Having a short half life makes such an activator responsive to changes in cell size and makes specific predictions for how cells respond to perturbation. In particular, it explains the curious phenomenon of excess mitotic delay. Excess mitotic delay, first observed in Tetrahymena in the '50s, is a phenomenon in which a pulse of protein synthesis inhibition causes a delay in mitotic entry that is longer than the pulse and that gets longer the later in the cell cycle the pulse is delivered. The interpretation of this phenomenon championed by Zeuthen and Mitchison in the '60s and '70s is that an unstable activator of mitosis is degraded during the pulse and has to be resynthesized to a threshold level to trigger mitosis; small cells have more time to resynthesize the activator before mitosis and so suffer less excess delay, whereas, large cells have less time thus suffer greater excess delay. Fifty years later, with our detailed understanding of cell cycle biochemistry, we can identify and test candidate Unstable Accumulating Activators. Here I review the field and further develop this concept.
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Affiliation(s)
- Nicholas Rhind
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA
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Schemarova IV, Selivanova GV, Vlasova TD. Influence of activator and inhibitors of Ca2+ channels on proliferative activity in Tetrahymena pyriformis infusoria. Russ J Dev Biol 2012. [DOI: 10.1134/s1062360412040078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Kitsios G, Doonan JH. Cyclin dependent protein kinases and stress responses in plants. PLANT SIGNALING & BEHAVIOR 2011; 6:204-9. [PMID: 21512322 PMCID: PMC3121979 DOI: 10.4161/psb.6.2.14835] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Revised: 01/13/2011] [Accepted: 01/15/2011] [Indexed: 05/18/2023]
Abstract
Plants have to adjust, grow and establish themselves in various changing environmental conditions. Additionally, the sessile life-style of plants requires the development of response mechanisms for their adaptation in such environmental cues. Under biotic and abiotic stress, plant growth is negatively affected mainly as a result of cell cycle inhibition. The perception of stress involves the activation of signaling cascades that result in a prolonged S-phase and delayed entry into mitosis. Although the molecular interactions that link the cell cycle machinery to perception of stress are not fully understood, recent studies indicated the involvement of Cyclin Dependent Kinases (CDKs) in the plant response machinery. CDKs are core cell cycle regulators but their activity has been implicated in additional diverse cellular processes. Here we review the impact of different types of abiotic stress on plant cell cycle progression and CDK activity, and discuss the contribution of CDK function in the signaling control of stress tolerance.
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Affiliation(s)
- Georgios Kitsios
- Agricultural University of Athens, Agricultural Biotechnology, Athens, Greece
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Fourrat L, Iddar A, Valverde F, Serrano A, Soukri A. Effects of oxidative and nitrosative stress on Tetrahymena pyriformis glyceraldehyde-3-phosphate dehydrogenase. J Eukaryot Microbiol 2008; 54:338-46. [PMID: 17669159 DOI: 10.1111/j.1550-7408.2007.00275.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Previous reports showed that hydrogen peroxide and the NO-generating reagent sodium nitroprusside (SNP)-modulated enzymatic activity of animal glyceraldehyde-3-phosphate dehydrogenase (GAPDH, EC 1.2.1.12). These modifications are suggested to have a physiological regulatory role. To gain further insight into this regulatory process the model ciliated protozoan Tetrahymena pyriformis was chosen. Both reagents inhibited growth of T. pyriformis cultures and produced a specific increase of GAPDH protein but only NO seemed to reduce GAPDH activity in cell-free extracts. Both specific activity and pI were found to be altered in the in vivo NO-treated purified enzyme, but no effect was detected by the in vivo H(2)O(2) treatment. Analytical chromatofocusing showed a single basic isoform (pI 8.8) in enzyme preparations from control and H(2)O(2)-treated cells. In contrast to this, three more acidic isoforms (pIs, 8.6, 8.0 and 7.3) were resolved in purified fractions from SNP-treated cells, suggesting post-translational modification of the enzyme by NO. Nevertheless, a decrease of GAPDH activity by H(2)O(2) and NO, mainly due to a decrease in its V(max) without apparent change in substrate affinity, was observed in vitro in the whole enzyme population. The increase of GAPDH protein level found in vivo suggests a cell response in order to compensate for the inhibitory effect on activity observed in the purified enzyme. This is the first report of NO- and H(2)O(2)-dependent effects on GAPDH of T. pyriformis, and identifies this key protein of central carbon metabolism as a physiological target of oxidative and nitrosative stress in this ciliated protozoan.
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Affiliation(s)
- Latifa Fourrat
- Laboratoire de Physiologie et Génétique moléculaire, Département de Biologie, Faculté des Sciences Aïn-Chock, Université Hassan-II, Km 8 route d'El Jadida, B.P. 5366 Mâarif, Casablanca, Morocco
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HELLUNG-LARSEN PER, LYHNE INGER. Effect of Shaking on the Growth of Diluted Cultures ofTetrahymena. ACTA ACUST UNITED AC 2007. [DOI: 10.1111/j.1550-7408.1992.tb01328.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Eugen-Olsen J, Hagemeister JJ, Hellung-Larsen P. Expression of Tetrahymena snRNA gene variants including a U1 gene with mutations in the 5' splice site recognition sequence. Gene 1997; 189:221-5. [PMID: 9168131 DOI: 10.1016/s0378-1119(96)00852-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The expression of U1, U2 and U5 snRNA gene variants has been studied under different physiological states of Tetrahymena. Variants of all three snRNA genes are expressed. Among the snRNAs detected is U1-3, a variant with 66 mutations compared to the normal U1 snRNA. Three of these mutations affect the 5' splice site recognition sequence. The U1-3 snRNA is present in a few hundred copies per cell. The expression of Tetrahymena snRNA genes is independent of the physiological state of the cell.
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Affiliation(s)
- J Eugen-Olsen
- Institute of Medical Biochemistry and Genetics, The Panum Institute, University of Copenhagen, Denmark
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Goodman JI, Rothenberg RJ. A procedure for examining deoxyribonucleic acid synthesis in regenerating liver in vitro. ACTA ACUST UNITED AC 1978. [DOI: 10.1016/0160-5402(78)90061-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Andersen HA. Replication and functions of macronuclear DNA in synchronously growing populations of Tetrahymena pyriformis. ACTA ACUST UNITED AC 1977. [DOI: 10.1007/bf02910452] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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