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Dündar Orhan Y, Üstüntanır Dede AF, Duran Ş, Arslanyolu M. Use of E-64 cysteine protease inhibitor for the recombinant protein production in Tetrahymena thermophila. Eur J Protistol 2024; 94:126085. [PMID: 38703600 DOI: 10.1016/j.ejop.2024.126085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 04/24/2024] [Accepted: 04/24/2024] [Indexed: 05/06/2024]
Abstract
Tetrahymena thermophila is an alternative organism for recombinant protein production. However, the production efficiency in T. thermophila is quite low mainly due to the rich cysteine proteases. In this study, we studied whether supplementation of the E-64 inhibitor to T. thermophila cultures increases the recombinant protein production efficiency without any toxic side effects. Our study showed that supplementation of E-64 had no lethal effects on T. thermophila cells in flask culture at 30 °C and 38 °C. In vitro protease activity analysis using secretome as protease enzyme source from E-64-supplemented cell cultures showed a reduced protein substrate degradation using bovine serum albumin, rituximab, and milk lactoglobulin proteins. E-64 also prevented proteolysis of the recombinantly produced and secreted TtmCherry2-sfGFP fusion protein at some level. This reduced inhibitory effect of E-64 could be due to genetic compensation of the inhibited proteases. As a result, the 5 µM concentration of E-64 was found to be a non-toxic protease inhibitory supplement to improve extracellular recombinant protein production efficiency in T. thermophila. This study suggests that the use of E-64 may increase the efficiency of extracellular recombinant protein production by continuously reducing extracellular cysteine protease activity during cultivation.
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Affiliation(s)
- Yeliz Dündar Orhan
- Department of Advanced Technologies, Institute of Graduate Programs, Eskisehir Technical University, Yunus Emre Campus, Eskişehir 26470, Turkey.
| | - Ayça Fulya Üstüntanır Dede
- Department of Biology, Institute of Graduate Programs, Eskisehir Technical University, Yunus Emre Campus, Eskişehir 26470, Turkey.
| | - Şeyma Duran
- Department of Molecular Biology, Institute of Graduate Programs, Eskisehir Technical University, Yunus Emre Campus, Eskişehir 26470, Turkey.
| | - Muhittin Arslanyolu
- Department of Biology, Faculty of Sciences, Eskisehir Technical University, Yunusemre Campus, Eskişehir 26470, Turkey.
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Brans V, Manzi F, Jacob S, Schtickzelle N. Demography and movement patterns of a freshwater ciliate: The influence of oxygen availability. Ecol Evol 2024; 14:e11291. [PMID: 38660468 PMCID: PMC11040103 DOI: 10.1002/ece3.11291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 03/27/2024] [Accepted: 04/05/2024] [Indexed: 04/26/2024] Open
Abstract
In freshwater habitats, aerobic animals and microorganisms can react to oxygen deprivation by a series of behavioural and physiological changes, either as a direct consequence of hindered performance or as adaptive responses towards hypoxic conditions. Since oxygen availability can vary throughout the water column, different strategies exist to avoid hypoxia, including that of active 'flight' from low-oxygen sites. Alternatively, some organisms may invest in slower movement, saving energy until conditions return to more favourable levels, which may be described as a 'sit-and-wait' strategy. Here, we aimed to determine which, if any, of these strategies could be used by the freshwater ciliate Tetrahymena thermophila when faced with decreasing levels of oxygen availability in the culture medium. We manipulated oxygen flux into clonal cultures of six strains (i.e. genotypes) and followed their growth kinetics for several weeks using automated image analysis, allowing to precisely quantify changes in density, morphology and movement patterns. Oxygen effects on demography and morphology were comparable across strains: reducing oxygen flux decreased the growth rate and maximal density of experimental cultures, while greatly expanding the duration of their stationary phase. Cells sampled during their exponential growth phase were larger and had a more elongated shape under hypoxic conditions, likely mirroring a shift in resource investment towards individual development rather than frequent divisions. In addition to these general patterns, we found evidence for intraspecific variability in movement responses to oxygen limitation. Some strains showed a reduction in swimming speed, potentially associated with a 'sit-and-wait' strategy; however, the frequent alteration of movement paths towards more linear trajectories also suggests the existence of an inducible 'flight response' in this species. Considering the inherent costs of turns associated with non-linear movement, such a strategy may allow ciliates to escape suboptimal environments at a low energetic cost.
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Affiliation(s)
- Victor Brans
- Biodiversity Research Centre, Earth and Life InstituteUniversité catholique de LouvainLouvain‐la‐NeuveBelgium
| | - Florent Manzi
- Biodiversity Research Centre, Earth and Life InstituteUniversité catholique de LouvainLouvain‐la‐NeuveBelgium
| | - Staffan Jacob
- Centre National de la Recherche Scientifique (CNRS)Station d'Ecologie Théorique et Expérimentale (UAR2029)MoulisFrance
| | - Nicolas Schtickzelle
- Biodiversity Research Centre, Earth and Life InstituteUniversité catholique de LouvainLouvain‐la‐NeuveBelgium
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Jacob S, Wehi P, Clobert J, Legrand D, Schtickzelle N, Huet M, Chaine A. Cooperation-mediated plasticity in dispersal and colonization. Evolution 2016; 70:2336-2345. [DOI: 10.1111/evo.13028] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 07/21/2016] [Accepted: 07/25/2016] [Indexed: 11/29/2022]
Affiliation(s)
- Staffan Jacob
- Station d'Ecologie Théorique et Expérimentale du CNRS; UMR 5321; 09200 Saint-Girons France
- Université Catholique de Louvain; Earth and Life Institute and Biodiversity Research Centre; Croix du Sud 4, L7-07-04 1348 Louvain-la-Neuve Belgium
| | - Priscilla Wehi
- Station d'Ecologie Théorique et Expérimentale du CNRS; UMR 5321; 09200 Saint-Girons France
- Current Address: Landcare Research Manaaki Whenua; Private Bag 1930 Dunedin 9054 New Zealand
| | - Jean Clobert
- Station d'Ecologie Théorique et Expérimentale du CNRS; UMR 5321; 09200 Saint-Girons France
| | - Delphine Legrand
- Station d'Ecologie Théorique et Expérimentale du CNRS; UMR 5321; 09200 Saint-Girons France
- Université Catholique de Louvain; Earth and Life Institute and Biodiversity Research Centre; Croix du Sud 4, L7-07-04 1348 Louvain-la-Neuve Belgium
| | - Nicolas Schtickzelle
- Université Catholique de Louvain; Earth and Life Institute and Biodiversity Research Centre; Croix du Sud 4, L7-07-04 1348 Louvain-la-Neuve Belgium
| | - Michele Huet
- Station d'Ecologie Théorique et Expérimentale du CNRS; UMR 5321; 09200 Saint-Girons France
| | - Alexis Chaine
- Station d'Ecologie Théorique et Expérimentale du CNRS; UMR 5321; 09200 Saint-Girons France
- Institute for Advanced Studies in Toulouse; Toulouse School of Economics; 21 allée de Brienne 31015 Toulouse France
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4
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Jacob S, Chaine AS, Schtickzelle N, Huet M, Clobert J. Social information from immigrants: multiple immigrant-based sources of information for dispersal decisions in a ciliate. J Anim Ecol 2015; 84:1373-83. [DOI: 10.1111/1365-2656.12380] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 04/20/2015] [Indexed: 12/01/2022]
Affiliation(s)
- Staffan Jacob
- Station d'Ecologie Expérimentale du CNRS à Moulis; USR CNRS 2936; 2 route du CNRS 09200 Moulis France
| | - Alexis S. Chaine
- Station d'Ecologie Expérimentale du CNRS à Moulis; USR CNRS 2936; 2 route du CNRS 09200 Moulis France
| | - Nicolas Schtickzelle
- Earth and Life Institute & Biodiversity Research Centre; Université catholique de Louvain; Croix du Sud 4 L7.07.04 1348 Louvain-la-Neuve Belgium
| | - Michèle Huet
- Station d'Ecologie Expérimentale du CNRS à Moulis; USR CNRS 2936; 2 route du CNRS 09200 Moulis France
| | - Jean Clobert
- Station d'Ecologie Expérimentale du CNRS à Moulis; USR CNRS 2936; 2 route du CNRS 09200 Moulis France
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Fronhofer EA, Kropf T, Altermatt F. Density-dependent movement and the consequences of the Allee effect in the model organism Tetrahymena. J Anim Ecol 2014; 84:712-722. [DOI: 10.1111/1365-2656.12315] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 10/26/2014] [Indexed: 11/27/2022]
Affiliation(s)
- Emanuel A. Fronhofer
- Department of Aquatic Ecology; Eawag: Swiss Federal Institute of Aquatic Science and Technology; Überlandstrasse 133 CH-8600 Dübendorf Switzerland
| | - Tabea Kropf
- Department of Environmental Systems Science; ETH Zürich; CH-8092 Zürich Switzerland
| | - Florian Altermatt
- Department of Aquatic Ecology; Eawag: Swiss Federal Institute of Aquatic Science and Technology; Überlandstrasse 133 CH-8600 Dübendorf Switzerland
- Institute of Evolutionary Biology and Environmental Studies; University of Zurich; Winterthurerstrasse 190 CH-8057 Zürich Switzerland
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6
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Simon MC, Kusch J. Communicative functions of GPI-anchored surface proteins in unicellular eukaryotes. Crit Rev Microbiol 2012; 39:70-8. [DOI: 10.3109/1040841x.2012.691459] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Csaba G. The hormonal system of the unicellular Tetrahymena: a review with evolutionary aspects. Acta Microbiol Immunol Hung 2012; 59:131-56. [PMID: 22750776 DOI: 10.1556/amicr.59.2012.2.1] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The unicellular ciliate, Tetrahymena has receptors for hormones of the higher ranked animals, these hormones (e.g. insulin, triiodothyronine, ACTH, histamine, etc.) are also produced by it and it has signal pathways and second messengers for signal transmission. These components are chemically and functionally very similar to that of mammalian ones. The exogenously given hormones regulate different functions, as movement, phagocytosis, chemotaxis, cell growth, secretion, excretion and the cells' own hormone production. The receptors are extremely sensitive, certain hormones are sensed (and response is provoked) at 10-21 M concentration, which makes likely that the function could work by the effect of hormones produced by the Tetrahymena itself. The signal reception is selective, it can differentiate between closely related hormones. The review is listing the hormones produced by the Tetrahymena, the receptors which can receive signals and the signal pathways and second messengers as well, as the known effects of mammalian hormones to the life functions of Tetrahymena. The possible and justified role of hormonal system in the Tetrahymena as a single cell and inside the Tetrahymena population, as a community is discussed. The unicellular hormonal system and mammalian endocrine system are compared and evolutionary conclusions are drawn.
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Affiliation(s)
- György Csaba
- 1 Semmelweis University Department of Genetics, Cell and Immunobiology Budapest Hungary
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8
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Abstract
Recognition of relatives is important in microbes because they perform many behaviors that have costs to the actor while benefiting neighbors. Microbes cooperate for nourishment, movement, virulence, iron acquisition, protection, quorum sensing, and production of multicellular biofilms or fruiting bodies. Helping others is evolutionarily favored if it benefits others who share genes for helping, as specified by kin selection theory. If microbes generally find themselves in clonal patches, then no special means of discrimination is necessary. Much real discrimination is actually of kinds, not kin, as in poison-antidote systems, such as bacteriocins, in which cells benefit their own kind by poisoning others, and in adhesion systems, in which cells of the same kind bind together. These behaviors can elevate kinship generally and make cooperation easier to evolve and maintain.
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Affiliation(s)
- Joan E Strassmann
- Department of Ecology and Evolutionary Biology, Rice University, Houston, Texas 77005, USA.
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Cassidy-Hanley DM. Tetrahymena in the laboratory: strain resources, methods for culture, maintenance, and storage. Methods Cell Biol 2012; 109:237-76. [PMID: 22444147 PMCID: PMC3608402 DOI: 10.1016/b978-0-12-385967-9.00008-6] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/06/2022]
Abstract
The ciliated protozoan Tetrahymena thermophila has been an important model system for biological research for many years. During that time, a variety of useful strains, including highly inbred stocks, a collection of diverse mutant strains, and wild cultivars from a variety of geographical locations have been identified. In addition, thanks to the efforts of many different laboratories, optimal conditions for growth, maintenance, and storage of Tetrahymena have been worked out. To facilitate the efficient use of Tetrahymena, especially by those new to the system, this chapter presents a brief description of many available Tetrahymena strains and lists possible resources for obtaining viable cultures of T. thermophila and other Tetrahymena species. Descriptions of commonly used media, methods for cell culture and maintenance, and protocols for short- and long-term storage are also presented.
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Affiliation(s)
- Donna M Cassidy-Hanley
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
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Chaine AS, Schtickzelle N, Polard T, Huet M, Clobert J. Kin-based recognition and social aggregation in a ciliate. Evolution 2009; 64:1290-300. [PMID: 19930455 DOI: 10.1111/j.1558-5646.2009.00902.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aggregative groups entail costs that must be overcome for the evolution of complex social interactions. Understanding the mechanisms that allow aggregations to form and restrict costs of cheating can provide a resolution to the instability of social evolution. Aggregation in Tetrahymena thermophila is associated with costs of reduced growth and benefits of improved survival through "growth factor" exchange. We investigated what mechanisms contribute to stable cooperative aggregation in the face of potential exploitation by less-cooperative lines using experimental microcosms. We found that kin recognition modulates aggregative behavior to exclude cheaters from social interactions. Long-distance kin recognition across patches modulates social structure by allowing recruitment of kin in aggregative lines and repulsion in asocial lines. Although previous studies have shown a clear benefit to social aggregation at low population densities, we found that social aggregation has very different effects at higher densities. Lower growth rates are a cost of aggregation, but also present potential benefits when restricted to kin aggregations: slow growth and crowd tolerance allow aggregations to form and permit longer persistence on ephemeral resources. Thus in highly dynamic metapopulations, kin recognition plays an important role in the formation and stability of social groups that increase persistence through cooperative consumptive restraint.
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Affiliation(s)
- Alexis S Chaine
- Station d'Ecologie Expérimentale du CNRS à Moulis USR2936, 09200 Saint-Girons, France.
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11
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Rasmussen MI, Wheatley DN. Purification and characterisation of cell survival factor 1 (TCSF1) from Tetrahymena thermophila. J Cell Commun Signal 2008; 1:185-93. [PMID: 18600478 DOI: 10.1007/s12079-007-0016-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2007] [Accepted: 12/26/2007] [Indexed: 11/30/2022] Open
Abstract
Of a number of peptides isolated from the extracellular medium of Tetrahymena cultures, two with masses 9.9 and 22.4 kDa allowed low-density cultures of this ciliate to survive and enter a proliferate phase. The smaller peptide (TCSF1) also greatly helped cultured mammalian fibroblasts to survive in medium containing very low concentrations of serum for considerably longer than controls, and to grow when full strength medium was restored. The primary sequence of the TCSF1 was determined, and synthetic TCSF1 was observed to exhibit rescuing activity comparable to that of the native peptide.
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12
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Fjerdingstad EJ, Schtickzelle N, Manhes P, Gutierrez A, Clobert J. Evolution of dispersal and life history strategies--Tetrahymena ciliates. BMC Evol Biol 2007; 7:133. [PMID: 17683620 PMCID: PMC1997130 DOI: 10.1186/1471-2148-7-133] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2007] [Accepted: 08/06/2007] [Indexed: 05/16/2023] Open
Abstract
BACKGROUND Considerable attention has focused on how selection on dispersal and other core life-history strategies (reproductive effort, survival ability, colonization capacity) may lead to so-called dispersal syndromes. Studies on genetic variation in these syndromes within species could importantly increase our understanding of their evolution, by revealing whether traits co-vary across genetic lineages in the manner predicted by theoretical models, and by stimulating further hypotheses for experimental testing. Yet such studies remain scarce. Here we studied the ciliated protist Tetrahymena thermophila, a particularly interesting organism due to cells being able to transform into morphs differing dramatically in swim-speed. We investigated dispersal, morphological responses, reproductive performance, and survival in ten different clonal strains. Then, we examined whether life history traits co-varied in the manner classically predicted for ruderal species, examined the investment of different strains into short- and putative long-distance dispersal, while considering also the likely impact of semi-sociality (cell aggregation, secretion of 'growth factors') on dispersal strategies. RESULTS Very significant among-strain differences were found with regard to dispersal rate, morphological commitment and plasticity, and almost all core life-history traits (e.g. survival, growth performance and strategy), with most of these traits being significantly intercorrelated. Some strains showed high short-distance dispersal rates, high colonization capacity, bigger cell size, elevated growth performance, and good survival abilities. These well performing strains, however, produced fewer fast-swimming dispersal morphs when subjected to environmental degradation than did philopatric strains performing poorly under normal conditions. CONCLUSION Strong evidence was found for a genetic covariation between dispersal strategies and core life history traits in T. thermophila, with a fair fit of observed trait associations with classic colonizer models. However, the well performing strains with high colonization success and short-distance dispersal likely suffered under a long-distance dispersal disadvantage, due to producing fewer fast-swimming dispersal morphs than did philopatric strains. The smaller cell size at carrying capacity of the latter strains and their poor capacity to colonize as individual cells suggest that they may be adapted to greater levels of dependency on clone-mates (stronger sociality). In summary, differential exposure to selection on competitive and cooperative abilities, in conjunction with selective factors targeting specifically dispersal distance, likely contributed importantly to shaping T. thermophila dispersal and life history evolution.
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Affiliation(s)
- Else J Fjerdingstad
- Laboratoire d'Ecologie, CNRS UMR 7625, Université Pierre et Marie Curie, Paris, France
- Now at the Department of Biology, Queens College, City University of New York, Flushing, NY, USA
| | - Nicolas Schtickzelle
- Laboratoire d'Ecologie, CNRS UMR 7625, Université Pierre et Marie Curie, Paris, France
- Biodiversity Research Centre, Université catholique de Louvain, Croix du Sud 4, 1348 Louvain-la-Neuve, Belgium
| | - Pauline Manhes
- Laboratoire d'Ecologie, CNRS UMR 7625, Université Pierre et Marie Curie, Paris, France
- Now at the Department of Biology, Indiana University, Bloomington, IN, USA
| | - Arnaud Gutierrez
- Laboratoire d'Ecologie, CNRS UMR 7625, Université Pierre et Marie Curie, Paris, France
- Laboratoire d'Ecologie, CNRS UMR 7625, Université Pierre et Marie Curie, Paris, France
| | - Jean Clobert
- Laboratoire d'Ecologie, CNRS UMR 7625, Université Pierre et Marie Curie, Paris, France
- Station d'Ecologie Expérimentale du CNRS à Moulis, Laboratoire Evolution et Diversité Biologique, Moulis, 09200 Saint-Girons, France
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Welburn SC, Macleod E, Figarella K, Duzensko M. Programmed cell death in African trypanosomes. Parasitology 2006; 132 Suppl:S7-S18. [PMID: 17018168 DOI: 10.1017/s0031182006000825] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Until recently it had generally been assumed that apoptosis and other forms of programmed cell death evolved during evolution of the metazoans to regulate growth and development in these multicellular organisms. However, recent research is adding strength to the original phenotypic observations described almost a decade ago which indicated that some parasitic protozoa may have evolved a cell death pathway analogous to the process described as apoptosis in metazoa. Here we explore the implications of a programmed cell death pathway in the African tsetse-transmitted trypanosomes.
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Affiliation(s)
- S C Welburn
- Centre for Infectious Diseases, College of Medicine and Veterinary Medicine, University of Edinburgh, EH25 9RG.
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Xu DH, Klesius PH, Shoemaker CA. Apoptosis in Ichthyophthirius multifiliis is associated with expression of the Fas receptor of theronts. JOURNAL OF FISH DISEASES 2006; 29:225-32. [PMID: 16635062 DOI: 10.1111/j.1365-2761.2006.00709.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The expression of type I membrane Fas receptors on the surface of Ichthyophthirius multifiliis (Ich) theronts and the possible association between Fas expression and theront apoptosis induced by the immune antibody was examined. Fas receptors were detected on the theront surface using fluorescein isothiocyanate-conjugated mouse monoclonal antibody against Fas. Fas-positive theronts significantly increased with time during in vitro incubation and with increasing theront concentration. Furthermore, the immune cutaneous antibody induced theront apoptosis; however, Fas ligand did not. A highly significant correlation was noted between theront Fas expression and immune cutaneous antibody-induced theront apoptosis. Numbers of apoptotic theronts increased with increasing number of Fas-positive theronts. The data indicated that theront apoptosis induced by immune cutaneous antibody appears to be positively correlated with the expression of Fas on the surface of Ich theronts.
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Affiliation(s)
- D-H Xu
- Aquatic Animal Health Research Laboratory, Agricultural Research Service, US Department of Agriculture, Auburn, AL 36831-0952, USA.
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15
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Xu DH, Klesius PH, Shoemaker CA. Cutaneous antibodies from channel catfish, Ictalurus punctatus (Rafinesque), immune to Ichthyophthirius multifiliis (Ich) may induce apoptosis of Ich theronts. JOURNAL OF FISH DISEASES 2005; 28:213-220. [PMID: 15813863 DOI: 10.1111/j.1365-2761.2005.00622.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
This study explored the existence of apoptosis (programmed cell death) in Ichthyophthirius multifiliis Fouquet (Ich) theronts and determined the effect of cutaneous antibodies in skin culture fluid from fish immune to Ich on theront apoptosis. Apoptosis was detected in theronts and was clearly distinguished by fluorescent microscopy after staining with acridine orange and propidium iodide. The apoptotic theronts showed characteristic chromatin condensation and nuclear fragments containing chromatin pieces. The externalization of phosphatidylserine on the plasma membrane of apoptotic theronts was detected with fluorescein isothiocyanate-conjugated annexin using flow cytometry. Theront apoptosis was induced using the skin culture fluid from fish immune to Ich, which contained cutaneous antibodies against Ich. The highest apoptosis appeared in theronts exposed to immune skin culture fluid at a 1:10 dilution, compared with those at 1:20 and 1:40 dilutions. A direct correlation was noted between the percentage of apoptotic theronts and exposure duration to immune skin culture fluid. The study indicated that antibody reaction with theronts (immobilization) played an important role in theront apoptosis, but it could not be excluded that other components released from the excised skin had effects on theronts.
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Affiliation(s)
- D-H Xu
- Aquatic Animal Health Research Laboratory, Agricultural Research Service, US Department of Agriculture, Auburn, AL 36831, USA.
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16
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Hellung-Larsen P. Cloning of Tetrahymena cells in a chemically defined medium is possible in the presence of surfactants or at reduced temperature. J Biotechnol 2005; 115:167-77. [PMID: 15607235 DOI: 10.1016/j.jbiotec.2004.08.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2004] [Revised: 06/03/2004] [Accepted: 08/23/2004] [Indexed: 11/19/2022]
Abstract
When Tetrahymena cells are exposed to physical or chemical stress they may die. The effect of a given stress depends on the culture medium, the temperature, and the manipulation of the cells. Cells in broth-medium or buffer solution are more resistant than cells in chemically defined medium (CDM). A type of physical stress is caused by the hydrodynamic properties at the constriction of the pipette tip. This type of stress may be reduced/abolished by use of tips with maximal area and smoothness at the constrictions, underwater delivery of cell suspensions combined with gentle mixing, by use of reduced temperatures, by avoidance of medium-air interfaces or by addition of surfactants. By adjustment of these parameters it is possible to clone single cells of different species of Tetrahymena in CDM. In the presence of surfactants, cells can be cloned even under harsh manipulation. In absence of surfactants, cells can be cloned at 15 degrees C using mild manipulations. Tetrahymena cells are independent of unspecific growth factors and they do not exert autocrine growth control. Pluronic does not bind to the cells with significant affinity. Chemical stress cannot be counteracted by surfactants. Pre-stress (heat) protects the cells from subsequent lethal heat stress.
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Affiliation(s)
- Per Hellung-Larsen
- IMBG, Department of Biochemistry B, The Panum Institute, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen N, Denmark.
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17
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Haas CN, Kaymak B. Effect of initial microbial density on inactivation of Giardia muris by ozone. WATER RESEARCH 2003; 37:2980-2988. [PMID: 12767301 DOI: 10.1016/s0043-1354(03)00112-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Inactivation of microorganisms by disinfectants frequently shows non-linear behavior on a semilogarithmic plot of log survival ratio versus time. A number of models have been developed to depict these deviations from Chick's Law. Some of the models predict that the log survival ratio (at a particular disinfectant dose and contact time, even in absence of demand) would be a function of the initial concentration of microorganisms (N(0)), while other models do not predict such an effect. The effect of N(0) on the survival ratio has not been deliberately tested. This work examined the inactivation of Giardia muris by ozone in batch systems, deliberately varying the disinfectant dose and N(0). It was found that the models predicting a dependency of survival on N(0) gave a better description to the data than models that did not predict such a dependency. Hence there is an apparent decrease in disinfection efficiency of ozone against Giardia muris (at pH 8 and 15 degrees C) as the initial microorganism concentration decreases. This phenomena should be taken into account by both disinfection researchers and by process design engineers.
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Affiliation(s)
- Charles N Haas
- Department of Civil, Architectural and Environmental Engineering, 33rd Market Streets, Drexel University, Philadelphia, PA 19104, USA.
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18
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Kobayashi T, Endoh H. Caspase-like activity in programmed nuclear death during conjugation of Tetrahymena thermophila. Cell Death Differ 2003; 10:634-40. [PMID: 12761572 DOI: 10.1038/sj.cdd.4401216] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Apoptosis, or programmed cell death, is common in a variety of eucaryotes, from unicellular protozoa to vertebrates. The ciliated protozoan Tetrahymena thermophila has a unique apoptosis-like nuclear death during conjugation, called programmed nuclear death. This death program involves nuclear condensation (pyknosis) and oligonucleosomal DNA fragmentation in the parental macronucleus. Subsequently, the condensed nucleus is entirely resorbed in the autophagosome. Here we demonstrate that caspase-8- and -9-like activity was detected, but no caspase-3-like activity, by in vitro assay during the nuclear resorption process, suggesting that caspase-like activity is associated with both programmed cell death and apoptosis-like nuclear death in Tetrahymena. The use of indicator dye to detect the loss of mitochondrial membrane potential suggested the uptake of mitochondria and the degenerating macronucleus by the autophagosome. An involvement of mitochondria in the programmed nuclear death is discussed.
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Affiliation(s)
- T Kobayashi
- Department of Biology, Faculty of Science, Kanazawa University, Japan
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Ekelund F, Frederiksen HB, Rønn R. Population dynamics of active and total ciliate populations in arable soil amended with wheat. Appl Environ Microbiol 2002; 68:1096-101. [PMID: 11872455 PMCID: PMC123724 DOI: 10.1128/aem.68.3.1096-1101.2002] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Soil protozoa are characterized by their ability to produce cysts, which allows them to survive unfavorable conditions (e.g., desiccation) for extended periods. Under favorable conditions, they may rapidly excyst and begin feeding, but even under optimal conditions, a large proportion of the population may be encysted. The factors governing the dynamics of active and encysted cells in the soil are not well understood. Our objective was to determine the dynamics of active and encysted populations of ciliates during the decomposition of freshly added organic material. We monitored, in soil microcosms, the active and total populations of ciliates, their potential prey (bacteria and small protozoa), their potential competitors (amoebae, flagellates, and nematodes), and their potential predators (nematodes). We sampled with short time intervals (2 to 6 days) and generated a data set, suitable for mathematical modeling. Following the addition of fresh organic material, bacterial numbers increased more than 1,400-fold. There was a temporary increase in the number of active ciliates, followed by a rapid decline, although the size of the bacterial prey populations remained high. During this initial burst of ciliate growth, the population of cystic ciliates increased 100-fold. We suggest that internal population regulation is the major factor governing ciliate encystment and that the rate of encystment depends on ciliate density. This model provides a quantitative explanation of ciliatostasis and can explain why protozoan growth in soil is less than that in aquatic systems. Internally governed encystment may be an essential adaptation to an unpredictable environment in which individual protozoa cannot predict when the soil will dry out and will survive desiccation only if they have encysted in time.
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Affiliation(s)
- Flemming Ekelund
- Department of Terrestrial Ecology, Zoological Institute, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen Ø, Denmark.
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