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Okuyama K, Nishigami Y, Ohmura T, Ichikawa M. Accumulation of Tetrahymena pyriformis on Interfaces. MICROMACHINES 2021; 12:mi12111339. [PMID: 34832750 PMCID: PMC8622496 DOI: 10.3390/mi12111339] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 10/28/2021] [Accepted: 10/29/2021] [Indexed: 11/29/2022]
Abstract
The behavior of ciliates has been studied for many years through environmental biology and the ethology of microorganisms, and recent hydrodynamic studies of microswimmers have greatly advanced our understanding of the behavioral dynamics at the single-cell level. However, the association between single-cell dynamics captured by microscopic observation and pattern dynamics obtained by macroscopic observation is not always obvious. Hence, to bridge the gap between the two, there is a need for experimental results on swarming dynamics at the mesoscopic scale. In this study, we investigated the spatial population dynamics of the ciliate, Tetrahymena pyriformis, based on quantitative data analysis. We combined the image processing of 3D micrographs and machine learning to obtain the positional data of individual cells of T. pyriformis and examined their statistical properties based on spatio-temporal data. According to the 3D spatial distribution of cells and their temporal evolution, cells accumulated both on the solid wall at the bottom surface and underneath the air–liquid interface at the top. Furthermore, we quantitatively clarified the difference in accumulation levels between the bulk and the interface by creating a simple behavioral model that incorporated quantitative accumulation coefficients in its solution. The accumulation coefficients can be compared under different conditions and between different species.
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Affiliation(s)
- Kohei Okuyama
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan;
| | - Yukinori Nishigami
- Research Institute for Electronic Science, Hokkaido University, Sapporo 001-0020, Japan;
| | - Takuya Ohmura
- Biozentrum, University of Basel, 4056 Basel, Switzerland;
| | - Masatoshi Ichikawa
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan;
- Correspondence: ; Tel.: +81-75-753-3749
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Johnson B, Altrock PM, Kimmel GJ. Two-dimensional adaptive dynamics of evolutionary public goods games: finite-size effects on fixation probability and branching time. ROYAL SOCIETY OPEN SCIENCE 2021; 8:210182. [PMID: 34084549 PMCID: PMC8150049 DOI: 10.1098/rsos.210182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 04/28/2021] [Indexed: 06/12/2023]
Abstract
Public goods games (PGGs) describe situations in which individuals contribute to a good at a private cost, but others can free-ride by receiving a share of the public benefit at no cost. The game occurs within local neighbourhoods, which are subsets of the whole population. Free-riding and maximal production are two extremes of a continuous spectrum of traits. We study the adaptive dynamics of production and neighbourhood size. We allow the public good production and the neighbourhood size to coevolve and observe evolutionary branching. We explain how an initially monomorphic population undergoes evolutionary branching in two dimensions to become a dimorphic population characterized by extremes of the spectrum of trait values. We find that population size plays a crucial role in determining the final state of the population. Small populations may not branch or may be subject to extinction of a subpopulation after branching. In small populations, stochastic effects become important and we calculate the probability of subpopulation extinction. Our work elucidates the evolutionary origins of heterogeneity in local PGGs among individuals of two traits (production and neighbourhood size), and the effects of stochasticity in two-dimensional trait space, where novel effects emerge.
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Affiliation(s)
- Brian Johnson
- Department of Integrated Mathematical Oncology, H. Lee Moffit Cancer Center and Research Institute, Tampa, FL 33612, USA
| | - Philipp M. Altrock
- Department of Integrated Mathematical Oncology, H. Lee Moffit Cancer Center and Research Institute, Tampa, FL 33612, USA
| | - Gregory J. Kimmel
- Department of Integrated Mathematical Oncology, H. Lee Moffit Cancer Center and Research Institute, Tampa, FL 33612, USA
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Dussutour A. Learning in single cell organisms. Biochem Biophys Res Commun 2021; 564:92-102. [PMID: 33632547 DOI: 10.1016/j.bbrc.2021.02.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 02/02/2021] [Accepted: 02/04/2021] [Indexed: 12/12/2022]
Abstract
The survival of all species requires appropriate behavioral responses to environmental challenges. Learning is one of the key processes to acquire information about the environment and adapt to changing and uncertain conditions. Learning has long been acknowledged in animals from invertebrates to vertebrates but remains a subject of debate in non-animal systems such a plants and single cell organisms. In this review I will attempt to answer the following question: are single cell organisms capable of learning? I will first briefly discuss the concept of learning and argue that the ability to acquire and store information through learning is pervasive and may be found in single cell organisms. Second, by focusing on habituation, the simplest form of learning, I will review a series of experiments showing that single cell organisms such as slime molds and ciliates display habituation and follow most of the criteria adopted by neuroscientists to define habituation. Then I will discuss disputed evidence suggesting that single cell organisms might also undergo more sophisticated forms of learning such as associative learning. Finally, I will stress out that the challenge for the future is less about whether or not to single cell organisms fulfill the definition of learning established from extensive studies in animal systems and more about acknowledging and understanding the range of behavioral plasticity exhibited by such fascinating organisms.
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Affiliation(s)
- Audrey Dussutour
- Research Centre on Animal Cognition (CRCA), Centre for Integrative Biology (CBI), Toulouse University, CNRS, UPS, Toulouse, 31062, AD, France.
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Farthing HN, Jiang J, Henwood AJ, Fenton A, Garner TWJ, Daversa DR, Fisher MC, Montagnes DJS. Microbial Grazers May Aid in Controlling Infections Caused by the Aquatic Zoosporic Fungus Batrachochytrium dendrobatidis. Front Microbiol 2021; 11:592286. [PMID: 33552011 PMCID: PMC7858660 DOI: 10.3389/fmicb.2020.592286] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 12/16/2020] [Indexed: 11/13/2022] Open
Abstract
Free-living eukaryotic microbes may reduce animal diseases. We evaluated the dynamics by which micrograzers (primarily protozoa) apply top-down control on the chytrid Batrachochytrium dendrobatidis (Bd) a devastating, panzootic pathogen of amphibians. Although micrograzers consumed zoospores (∼3 μm), the dispersal stage of chytrids, not all species grew monoxenically on zoospores. However, the ubiquitous ciliate Tetrahymena pyriformis, which likely co-occurs with Bd, grew at near its maximum rate (r = 1.7 d-1). A functional response (ingestion vs. prey abundance) for T. pyriformis, measured using spore-surrogates (microspheres) revealed maximum ingestion (I max ) of 1.63 × 103 zoospores d-1, with a half saturation constant (k) of 5.75 × 103 zoospores ml-1. Using these growth and grazing data we developed and assessed a population model that incorporated chytrid-host and micrograzer dynamics. Simulations using our data and realistic parameters obtained from the literature suggested that micrograzers could control Bd and potentially prevent chytridiomycosis (defined as 104 sporangia host-1). However, simulated inferior micrograzers (0.7 × I max and 1.5 × k) did not prevent chytridiomycosis, although they ultimately reduced pathogen abundance to below levels resulting in disease. These findings indicate how micrograzer responses can be applied when modeling disease dynamics for Bd and other zoosporic fungi.
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Affiliation(s)
- Hazel N. Farthing
- Shanghai Universities Key Laboratory of Marine Animal Taxonomy and Evolution, Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China
- Department of Evolution, Ecology and Behaviour, Biosciences Building, University of Liverpool, Liverpool, United Kingdom
| | - Jiamei Jiang
- Shanghai Universities Key Laboratory of Marine Animal Taxonomy and Evolution, Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China
| | - Alexandra J. Henwood
- Department of Evolution, Ecology and Behaviour, Biosciences Building, University of Liverpool, Liverpool, United Kingdom
| | - Andy Fenton
- Department of Evolution, Ecology and Behaviour, Biosciences Building, University of Liverpool, Liverpool, United Kingdom
| | - Trent W. J. Garner
- Institute of Zoology, Zoological Society of London, London, United Kingdom
| | - David R. Daversa
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, United Kingdom
| | - Matthew C. Fisher
- Department of Evolution, Ecology and Behaviour, Biosciences Building, University of Liverpool, Liverpool, United Kingdom
- Institute of Zoology, Zoological Society of London, London, United Kingdom
| | - David J. S. Montagnes
- Department of Evolution, Ecology and Behaviour, Biosciences Building, University of Liverpool, Liverpool, United Kingdom
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Effects of Gonadotropin-Releasing Hormone (GnRH) and Its Analogues on the Physiological Behaviors and Hormone Content of Tetrahymena pyriformis. Int J Mol Sci 2019; 20:ijms20225711. [PMID: 31739545 PMCID: PMC6888530 DOI: 10.3390/ijms20225711] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Revised: 11/11/2019] [Accepted: 11/12/2019] [Indexed: 12/17/2022] Open
Abstract
The unicellular Tetrahymena distinguishes structure-related vertebrate hormones by its chemosensory reactions. In the present work, the selectivity of hormone receptors was evaluated by analyzing the effects of various gonadotropin-releasing hormone (GnRH) analogs (GnRH-I, GnRH-III) as well as truncated (Ac-SHDWKPG-NH2) and dimer derivatives ([GnRH-III(C)]2 and [GnRH-III(CGFLG)]2) of GnRH-III on (i) locomotory behaviors, (ii) cell proliferation, and (iii) intracellular hormone contents of Tetrahymena pyriformis. The migration, intracellular hormone content, and proliferation of Tetrahymena were investigated by microscope-assisted tracking analysis, flow cytometry, and a CASY TT cell counter, respectively. Depending on the length of linker sequence between the two GnRH-III monomers, the GnRH-III dimers had the opposite effect on Tetrahymena migration. [GnRH-III(CGFLG)]2 dimer had a slow, serpentine-like movement, while [GnRH-III(C)]2 dimer had a rather linear swimming pattern. All GnRH-III derivatives significantly induced cell growth after 6 h incubation. Endogenous histamine content was uniformly enhanced by Ac-SHDWKPG-NH2 and GnRH-III dimers, while some differences between the hormonal activities of GnRHs were manifested in their effects on intracellular levels of serotonin and endorphin. The GnRH peptides could directly affect Tetrahymena migration and proliferation in a structure-dependent manner, and they could indirectly regulate these reactions by paracrine/autocrine mechanisms. Present results support the theory that recognition ability and selectivity of mammalian hormone receptors can be deduced from a phylogenetically ancient level like the unicellular Tetrahymena.
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Gaines A, Ludovice M, Xu J, Zanghi M, Meinersmann RJ, Berrang M, Daley W, Britton D. The dialogue between protozoa and bacteria in a microfluidic device. PLoS One 2019; 14:e0222484. [PMID: 31596855 PMCID: PMC6784911 DOI: 10.1371/journal.pone.0222484] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 08/30/2019] [Indexed: 01/28/2023] Open
Abstract
In nature, protozoa play a major role in controlling bacterial populations. This paper proposes a microfluidic device for the study of protozoa behaviors change due to their chemotactic response in the presence of bacterial cells. A three-channel microfluidic device was designed using a nitrocellulose membrane into which channels were cut using a laser cutter. The membrane was sandwiched between two glass slides; a Euglena suspension was then allowed to flow through the central channel. The two side channels were filled with either, 0.1% peptone as a negative control, or a Listeria suspension respectively. The membrane design prevented direct interaction but allowed Euglena cells to detect Listeria cells as secretions diffused through the nitrocellulose membrane. A significant number of Euglena cells migrated toward the chambers near the bacterial cells, indicating a positive chemotactic response of Euglena toward chemical cues released from Listeria cells. Filtrates collected from Listeria suspension with a series of molecular weight cutoffs (3k, 10k and 100k) were examined in Euglena chemotaxis tests. Euglena cells were attracted to all filtrates collected from the membrane filtration with different molecular weight cutoffs, suggesting small molecules from Listeria might be the chemical cues to attract protozoa. Headspace volatile organic compounds (VOC) released from Listeria were collected, spiked to 0.1% peptone and tested as the chemotactic effectors. It was discovered that the Euglena cells responded quickly to Listeria VOCs including decanal, 3,5- dimethylbenzaldehyde, ethyl acetate, indicating bacterial VOCs were used by Euglena to track the location of bacteria.
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Affiliation(s)
- Anna Gaines
- Aerospace, Transportation and Advanced Systems Laboratory, Georgia Tech Research Institute, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Miranda Ludovice
- Aerospace, Transportation and Advanced Systems Laboratory, Georgia Tech Research Institute, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Jie Xu
- Aerospace, Transportation and Advanced Systems Laboratory, Georgia Tech Research Institute, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Marc Zanghi
- Aerospace, Transportation and Advanced Systems Laboratory, Georgia Tech Research Institute, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Richard J. Meinersmann
- Richard B. Russell Research Center, Agricultural Research Service, United States Department of Agriculture, Athens, Georgia, United States of America
| | - Mark Berrang
- Richard B. Russell Research Center, Agricultural Research Service, United States Department of Agriculture, Athens, Georgia, United States of America
| | - Wayne Daley
- Aerospace, Transportation and Advanced Systems Laboratory, Georgia Tech Research Institute, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Doug Britton
- Aerospace, Transportation and Advanced Systems Laboratory, Georgia Tech Research Institute, Georgia Institute of Technology, Atlanta, Georgia, United States of America
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Coherent directed movement toward food modeled in Trichoplax, a ciliated animal lacking a nervous system. Proc Natl Acad Sci U S A 2019; 116:8901-8908. [PMID: 30979806 PMCID: PMC6500112 DOI: 10.1073/pnas.1815655116] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Trichoplax adhaerens is a small, ciliated marine animal that glides on surfaces grazing upon algae, which it digests externally. It has no muscles or nervous system and only six cell types, all but two of which are embedded in its epithelium. The epithelial cells are joined by apical adherens junctions; neither tight junctions nor gap junctions are present. Monociliated epithelial cells on the lower surface propel gliding. The cilia beat regularly, but asynchronously, and transiently contact the substrate with each stroke. The animal moves in random directions in the absence of food. We show here that it exhibits chemotaxis, moving preferentially toward algae embedded in a disk of agar. We present a mathematical model to explain how coherent, directional movements could arise from the collective actions of a set of ciliated epithelial cells, each independently sensing and responding to a chemoattractant gradient. The model incorporates realistic values for viscoelastic properties of cells and produces coordinated movements and changes in body shape that resemble the actual movements of the animal. The model demonstrates that an animal can move coherently in search of food without any need for chemical signaling between cells and introduces a different approach to modeling behavior in primitive multicellular organisms.
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9
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Composite random search strategies based on non-directional sensory cues. ECOLOGICAL COMPLEXITY 2015. [DOI: 10.1016/j.ecocom.2015.03.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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10
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Grønlien HK, Rønnevig AK, Hagen B, Sand O. Chemo-accumulation without changes in membrane potential in the microstome form of the ciliate Tetrahymena vorax. ACTA ACUST UNITED AC 2011; 213:3980-7. [PMID: 21075939 DOI: 10.1242/jeb.042903] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The swimming behaviour of ciliates is mainly determined by membrane potential and transmembrane fluxes. In a chemical gradient, swimming ciliates may approach or move away from the source. Based on experiments on Paramecium, it is generally assumed that chemical attractants and repellents affect the swimming behaviour of ciliates by specific changes in the membrane potential. We have examined whether there is a causal relationship between membrane potential and chemo-accumulation in the microstome form of the polymorphic ciliate Tetrahymena vorax. Effects of chemo-attractants on the membrane potential of Tetrahymena have not been previously reported. Microstome T. vorax cells aggregated close to a point source of l-cysteine and the complex meat hydrolysate proteose peptone. Chemo-accumulated cells displayed a significantly higher turning frequency than control cells at a similar cell density. A concentration of 20 mmol l(-1) l-cysteine did not evoke any detectable change in the membrane potential whereas 1% proteose peptone depolarised the cells by ∼12 mV. This is contrary to the current model, which predicts agents that induce a moderate depolarisation to be repellents. A solution of 1% proteose peptone contains 21 mmol(-1) Na(+). A solution of 21 mmol(-1) NaCl without organic compounds also caused ∼12 mV depolarisation but had no aggregating effect on the cells. Collectively, the electrophysiological and behavioural data indicate that chemo-accumulation in the microstome form of T. vorax is not governed obligatorily by the membrane potential. We thus suggest that the simple membrane potential model for chemokinesis in Paramecium may not be valid for T. vorax.
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Affiliation(s)
- Heidi K Grønlien
- Department of Molecular Biosciences, Physiology Program, University of Oslo, PO Box 1041 Blindern, NO-0316 Oslo, Norway.
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11
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Kőhidai L. Chemotaxis: the Proper Physiological Response to Evaluate Phylogeny of Signal Molecules. ACTA BIOLOGICA HUNGARICA 1999. [DOI: 10.1007/bf03543060] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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12
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Affiliation(s)
- J Frankel
- Department of Biological Sciences, University of Iowa, Iowa City 52242, USA
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STOCK CHRISTIAN, KRÜPPEL THOMAS, LUEKEN WOLFGANG. Kinesis in Euplotes vannus-Ethological and Electrophysiological Characteristics of Chemosensory Behavior. J Eukaryot Microbiol 1997. [DOI: 10.1111/j.1550-7408.1997.tb05719.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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14
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DOERDER FPAUL, ARSLANYOLU MUHITTIN, SAAD YASSER, KACZMAREK MICHELLE, MENDOZA MANUEL, MITA BARRY. Ecological Genetics ofTetrahymena thermophila:Mating Types, i-Antigens, Multiple Alleles and Epistasis. J Eukaryot Microbiol 1996. [DOI: 10.1111/j.1550-7408.1996.tb04487.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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15
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Leick V, Grave M, Hellung-Larsen P. Signal peptide-induced sensory behavior in free ciliates: bioassays and cellular mechanisms. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 1996; 17:61-79. [PMID: 8822800 DOI: 10.1007/978-3-642-80106-8_4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- V Leick
- Department of Biochemistry B, University of Copenhagen, Denmark
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16
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Doerder FP, Gates MA, Eberhardt FP, Arslanyolu M. High frequency of sex and equal frequencies of mating types in natural populations of the ciliate Tetrahymena thermophila. Proc Natl Acad Sci U S A 1995; 92:8715-8. [PMID: 7568003 PMCID: PMC41037 DOI: 10.1073/pnas.92.19.8715] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
In ciliate protists, sex involves the temporary joining of two cells of compatible mating type, followed by meiosis and exchange of gametic nuclei between conjugants. Reproduction is by asexual binary fission following conjugation. For the many ciliates with fixed multiple mating types, frequency-dependent sex-ratio theory predicts equal frequencies of mating types, if sex is common in nature. Here, we report that in natural populations of Tetrahymena thermophila sexually immature cells, indicative of recent conjugation, are found from spring through fall. In addition, the seven mating types occur in approximately equal frequencies, and these frequencies appear to be maintained by interaction between complex, multiple mat alleles and environmental conditions during conjugation. Such genotype-environment interaction determining mating type frequency is rare among ciliates.
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Affiliation(s)
- F P Doerder
- Department of Biology, Cleveland State University, OH 44115, USA
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17
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Csaba G, Kôhidai L. Effects of L-alanine and L-alanine peptides on the chemotaxis of tetrahymena: evolutionary conclusions. Biosci Rep 1995; 15:185-90. [PMID: 8562869 DOI: 10.1007/bf01540452] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
L-alanine and its peptides (L-Ala-2-6) do not attract or repulse Tetrahymena in a 10(-8) M concentration. In 10(-10) M concentration there is a consistent repellent effect. Twenty four hours after L-alanine or L-alanine-peptides' pretreatment (imprinting) the progeny generation of the cells react differently to the same materials. L-Alanine, L-alanine penta- and hexapeptide in both concentrations are chemoattractant, while L-alanine tetrapeptide is repellent. L-Alanine dipeptide is inert in 10(-10) M and repellent at 10(-8) M concentrations, while L-alanine tripeptide is strongly repellent at 10(-10) M and attractant at 10(-8) M concentrations. This means, that the first encounter (imprinting) with an exogenous amino acid or peptide is decisive to the later reaction of the protozoan cell. The chain length is important in the imprinting, however the reaction is not consistent. The experiments call the attention to the significance of imprinting in the receptor and hormone evolution.
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Affiliation(s)
- G Csaba
- Department of Biology, Semmelweis University of Medicine, Budapest, Hungary
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18
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Köhidai L, Csaba G. Effects of the mammalian vasoconstrictor peptide, endothelin-1, on Tetrahymena pyriformis GL, and the immunocytological detection of endogenous endothelin-like activity. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART C, PHARMACOLOGY, TOXICOLOGY & ENDOCRINOLOGY 1995; 111:311-6. [PMID: 8521250 DOI: 10.1016/0742-8413(95)00055-s] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The vasoconstrictor endothelin-1 (ET-1) is shown to have significant physiological effects on a unicellular organism, Tetrahymena pyriformis. These responses include: (1) A significant increase in intracellular [Ca2+] induced by 10(-10) M ET-1; (2) Increased chemotaxis, maximal at 10(-10) M; and (3) A small inhibition of proliferation at the 10(-13)-10(-12) M concentration range. Immunocytochemical detection of endogenous ET-1 using rabbit antibodies directed against human or porcine ET-1 indicates that this is a further example of the widening group of vertebrate hormones now known to be synthesized by Tetrahymena. These observations suggest that hormones are of considerable antiquity in their phylogenetic appearance and have been highly conserved throughout evolution.
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Affiliation(s)
- L Köhidai
- Department of Biology, Semmelweis University of Medicine, Budapest, Hungary
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19
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Abstract
Earlier works presented a variety of techniques for detection of chemoattractants in ciliates. The present agar layer model and the used double-P cutter give an easy, reproducible way of quantitative evaluation of positive chemotaxis. Beside the two-channel chamber, the multi-channel one seems to be also useful in characterization of different taxons or different chemoattractants.
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Affiliation(s)
- L Köhidai
- Department of Biology, Semmelweis University of Medicine, Budapest, Hungary
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20
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Leick V, Koppelhus U, Rosenberg J. Cilia-mediated oriented chemokinesis in Tetrahymena thermophila. J Eukaryot Microbiol 1994; 41:546-53. [PMID: 7866381 DOI: 10.1111/j.1550-7408.1994.tb01515.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The role of the cilia in the locomotion ("gliding") of Tetrahymena thermophila in a semi-solid medium has been studied when cells were migrating in gradients of attractant. Video recordings and computer-aided motion analysis of migrating cells and their ciliary activity show that Tetrahymena thermophila migrate by swimming forward in semi-solid methyl cellulose, using their cilia. Ciliary reversals occur at certain intervals and cause a termination ("stop") of cellular migration. Cells with reversed cilia resume forward migration when normal ciliary beating resumes. In gradients of attractants, cells migrating towards the attractant suppress ciliary reversals, which leads to longer runs between stops than in control cells. Cells migrating away from the attractant have a higher frequency of ciliary reversals than the control cells resulting in shorter runs. Stimulated cells adapt to a particular ambient concentration of attractant several times during migration in the gradient. Adaptation is followed by de-adaptation, which occurs during the "stop." In the presence of cycloheximide, a strong inhibitor of chemoattraction, the attractant-induced suppression of ciliary reversal is abolished (cells become desensitized to the attractant). It is concluded that Tetrahymena has a short-term memory during adaptation. This is important for the efficiency of migration towards an attractant.
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Affiliation(s)
- V Leick
- Department of Medical Biochemistry and Genetics, University of Copenhagen, Denmark
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21
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Wheatley DN, Rasmussen L, Tiedtke A. Tetrahymena: a model for growth, cell cycle and nutritional studies, with biotechnological potential. Bioessays 1994; 16:367-72. [PMID: 8024545 DOI: 10.1002/bies.950160512] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Tetrahymena has been used as a model cell system in many studies of morphogenesis, conjugation, gene mapping, cell division and growth kinetics. In this article, we consider some advances which have resulted from the successful development of a chemically defined medium (CDM), and how subsequent work has extended the contribution that this organism has made to our understanding of different aspects of growth, nutrition, cell cycle control, cytokinesis and intercellular signalling. Finally, we discuss the considerable potential that has arisen for the biotechnological exploitation of this big and rapidly growing eukaryotic cell.
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Affiliation(s)
- D N Wheatley
- Cell Pathology Laboratory, University Medical School, Foresterhill, Aberdeen, UK
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Abstract
It might appear curious to read about yeast, slime molds and protozoa in a journal dedicated to neuroscience. However, despite their distinct lack of synapses, eukaryotic microorganisms hold a wealth of information relevant to the signal-transduction pathways that underly activity in neuronal receptor cells, particularly those subserving the chemical senses. Microorganisms are sensitive to chemical stimuli from their environment and thus have similarities to receptor neurons of the olfactory system and the taste bud. Here, we introduce receptors, second messengers and effectors responsible for chemosensory signal transduction in yeast mating, sea-urchin spermatozoan chemotaxis, slime-mold aggregation and development, and ciliate chemoresponses.
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Affiliation(s)
- J Van Houten
- Dept of Zoology, University of Vermont, Burlington 05405
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23
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Phylogeny and Ontogeny of Chemical Signaling: Origin and Development of Hormone Receptors. INTERNATIONAL REVIEW OF CYTOLOGY 1994. [DOI: 10.1016/s0074-7696(08)62095-1] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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24
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Abstract
Myxococcus xanthus is a Gram-negative bacterium that glides on a solid surface and displays a wide range of social behaviour including microbial development. The frz genes are homologues to the chemotaxis genes of Escherichia coli and Salmonella typhimurium and have been shown to be involved in microbial development. However, chemotaxis has never been clearly demonstrated in Myxococcus. In this study, we showed that M. xanthus exhibited tactic movements to many chemicals when they were subjected to steep and stable chemical gradients. M. xanthus was observed to spread into areas with abundant nutrients like yeast extract or Casitone and avoid areas with no nutrients or repellents (short-chain alcohols or DMSO). Responses to attractants and repellents were additive. Movement towards attractants or away from repellents required the frz genes and was correlated with methylation or demethylation of FrzCD, a methyl-accepting taxis protein. Furthermore, the frz genes were found to be required for both fruiting body formation during starvation and swarming in nutrient-rich medium. In wild-type strains, cells near the colony edge were observed to swarm towards the surrounding growth medium and to contain highly methylated FrzCD; cells near the colony centre contained mainly demethylated FrzCD and showed directed movement towards the colony edge. FrzCD was also found to be methylated during the aggregation stage of fruiting body formation on agar but largely demethylated in cells shaken in liquid starvation media. An frzE mutant failed to exhibit directed cell movements and no longer showed modification of FrzCD under these conditions. These observations suggest that M. xanthus does show chemotactic movements, that these movements require the frz genes, and that chemotaxis plays a very important role in the social behaviour of this organism.
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Affiliation(s)
- W Shi
- Department of Molecular and Cell Biology, University of California, Berkeley 94720
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