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Hoque MM, Espinoza-Vergara G, McDougald D. Protozoan predation as a driver of diversity and virulence in bacterial biofilms. FEMS Microbiol Rev 2023; 47:fuad040. [PMID: 37458768 DOI: 10.1093/femsre/fuad040] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 06/19/2023] [Accepted: 07/07/2023] [Indexed: 07/27/2023] Open
Abstract
Protozoa are eukaryotic organisms that play a crucial role in nutrient cycling and maintaining balance in the food web. Predation, symbiosis and parasitism are three types of interactions between protozoa and bacteria. However, not all bacterial species are equally susceptible to protozoan predation as many are capable of defending against predation in numerous ways and may even establish either a symbiotic or parasitic life-style. Biofilm formation is one such mechanism by which bacteria can survive predation. Structural and chemical components of biofilms enhance resistance to predation compared to their planktonic counterparts. Predation on biofilms gives rise to phenotypic and genetic heterogeneity in prey that leads to trade-offs in virulence in other eukaryotes. Recent advances, using molecular and genomics techniques, allow us to generate new information about the interactions of protozoa and biofilms of prey bacteria. This review presents the current state of the field on impacts of protozoan predation on biofilms. We provide an overview of newly gathered insights into (i) molecular mechanisms of predation resistance in biofilms, (ii) phenotypic and genetic diversification of prey bacteria, and (iii) evolution of virulence as a consequence of protozoan predation on biofilms.
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Affiliation(s)
- M Mozammel Hoque
- Australian Institute for Microbiology & Infection, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Gustavo Espinoza-Vergara
- Australian Institute for Microbiology & Infection, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Diane McDougald
- Australian Institute for Microbiology & Infection, University of Technology Sydney, Sydney, NSW 2007, Australia
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2
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Gruzdev GA, Soboleva LV, Kamensky AA. The Effect of the Agonist Cholecystokinin-4 D-GB-115 On the Character of Motor Activity of Paramecium caudatum. DOKL BIOCHEM BIOPHYS 2023; 510:91-94. [PMID: 37582869 DOI: 10.1134/s1607672923700175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/11/2023] [Accepted: 01/12/2023] [Indexed: 08/17/2023]
Abstract
The study investigated the effect of GABA in various concentrations and D-GB-115 at a concentration of 10-7 M on the behavior of Paramecium caudatum. It was shown that GABA increases motor activity and changes the movement strategy of these protozoans, and the dose-effect relationship is domed, which can be explained by the presence of two types of GABA receptors in the outer membrane of paramecia: GABA-A and GABA-B. The active concentrations of GABA range from 10-3 to 10-13 M. The effect of pharmacological agents interacting with the GABA system on the behavior of ciliates (nembutal and D-GB-115) was studied.
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Abstract
The evolutionary theory of aging has set the foundations for a comprehensive understanding of aging. The biology of aging has listed and described the "hallmarks of aging," i.e., cellular and molecular mechanisms involved in human aging. The present paper is the first to infer the order of appearance of the hallmarks of bilaterian and thereby human aging throughout evolution from their presence in progressively narrower clades. Its first result is that all organisms, even non-senescent, have to deal with at least one mechanism of aging - the progressive accumulation of misfolded or unstable proteins. Due to their cumulation, these mechanisms are called "layers of aging." A difference should be made between the first four layers of unicellular aging, present in some unicellular organisms and in all multicellular opisthokonts, that stem and strike "from the inside" of individual cells and span from increasingly abnormal protein folding to deregulated nutrient sensing, and the last four layers of metacellular aging, progressively appearing in metazoans, that strike the cells of a multicellular organism "from the outside," i.e., because of other cells, and span from transcriptional alterations to the disruption of intercellular communication. The evolution of metazoans and eumetazoans probably solved the problem of aging along with the problem of unicellular aging. However, metacellular aging originates in the mechanisms by which the effects of unicellular aging are kept under control - e.g., the exhaustion of stem cells that contribute to replace damaged somatic cells. In bilaterians, additional functions have taken a toll on generally useless potentially limited lifespan to increase the fitness of organisms at the price of a progressively less efficient containment of the damage of unicellular aging. In the end, this picture suggests that geroscience should be more efficient in targeting conditions of metacellular aging rather than unicellular aging itself.
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Affiliation(s)
- Maël Lemoine
- CNRS, ImmunoConcEpT, UMR 5164, Univ. Bordeaux, Bordeaux, France
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4
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Abstract
Meaning has traditionally been regarded as a problem for philosophers and psychologists. Advances in cognitive science since the early 1960s, however, broadened discussions of meaning, or more technically, the semantics of perceptions, representations, and/or actions, into biology and computer science. Here, we review the notion of “meaning” as it applies to living systems, and argue that the question of how living systems create meaning unifies the biological and cognitive sciences across both organizational and temporal scales.
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Maurya R, Pandey AK. Importance of protozoa Tetrahymena in toxicological studies: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 741:140058. [PMID: 32599397 DOI: 10.1016/j.scitotenv.2020.140058] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 06/05/2020] [Accepted: 06/05/2020] [Indexed: 06/11/2023]
Abstract
Tetrahymena is a single-cell eukaryotic organism present in all aquatic environments and can easily be maintained in laboratory conditions in a cost-effective manner. This review gives a brief description of the physiology of Tetrahymena, culture handling, and maintenance of Tetrahymena species. The review article focuses on various toxicological bioassays at different biological organizational (biochemical, individual, population, and community) levels. Furthermore, some techniques such as single cell gel electrophoresis (SCGE) and microcalorimetry assay are also available to investigate the effect of xenobiotics on the integrity of DNA and metabolic state of Tetrahymena species respectively. The article also discusses how the general physiology, behavioural activities and different organelles of Tetrahymena could be useful in toxicological studies. The strength and limitations of Tetrahymena over other model organisms are also discussed. This article also provides suggestions to overcome some problems related to toxicity assessment. Various aspects associated with variability in results, toxicity endpoints, characteristics of organisms and responses against xenobiotic substances (old and new emerging toxicants) are considered.
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Affiliation(s)
- Renuka Maurya
- CSIR-Indian Institute of Toxicology Research, Vishvigyan Bhawan, 31, Mahatma Gandhi Marg, Lucknow, Uttar Pradesh, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - Alok Kumar Pandey
- CSIR-Indian Institute of Toxicology Research, Vishvigyan Bhawan, 31, Mahatma Gandhi Marg, Lucknow, Uttar Pradesh, India.
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6
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Fields C, Bischof J, Levin M. Morphological Coordination: A Common Ancestral Function Unifying Neural and Non-Neural Signaling. Physiology (Bethesda) 2020; 35:16-30. [DOI: 10.1152/physiol.00027.2019] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Nervous systems are traditionally thought of as providing sensing and behavioral coordination functions at the level of the whole organism. What is the evolutionary origin of the mechanisms enabling the nervous systems’ information processing ability? Here, we review evidence from evolutionary, developmental, and regenerative biology suggesting a deeper, ancestral function of both pre-neural and neural cell-cell communication systems: the long-distance coordination of cell division and differentiation required to create and maintain body-axis symmetries. This conceptualization of the function of nervous system activity sheds new light on the evolutionary transition from the morphologically rudimentary, non-neural Porifera and Placazoa to the complex morphologies of Ctenophores, Cnidarians, and Bilaterians. It further allows a sharp formulation of the distinction between long-distance axis-symmetry coordination based on external coordinates, e.g., by whole-organism scale trophisms as employed by plants and sessile animals, and coordination based on body-centered coordinates as employed by motile animals. Thus we suggest that the systems that control animal behavior evolved from ancient mechanisms adapting preexisting ionic and neurotransmitter mechanisms to regulate individual cell behaviors during morphogenesis. An appreciation of the ancient, non-neural origins of bioelectrically mediated computation suggests new approaches to the study of embryological development, including embryological dysregulation, cancer, regenerative medicine, and synthetic bioengineering.
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Affiliation(s)
- Chris Fields
- 23 Rue des Lavandières, Caunes Minervois, France
| | - Johanna Bischof
- Allen Discovery Center at Tufts University, Medford, Massachusetts
| | - Michael Levin
- Allen Discovery Center at Tufts University, Medford, Massachusetts
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Csaba G. Provocation of life functions at a unicellular eukaryote level by extremely low doses of mammalian hormones: Evidences of hormesis. Acta Microbiol Immunol Hung 2019; 67:1-5. [PMID: 31813260 DOI: 10.1556/030.66.2019.031] [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: 04/08/2019] [Accepted: 05/15/2019] [Indexed: 11/19/2022]
Abstract
Hormones, characteristic to higher ranked animals, are synthesized, stored, and secreted by unicellular eukaryote animals. The unicells also have receptors for recognizing these materials and transmit the message into the cells for provoking response. The hormones are effective in very low concentrations (down to 10-21 M) and opposite effects of lower and higher concentrations can be observed. However, sometimes linear concentration effects can be found, which means that hormesis exists, nevertheless uncertain, as it is in the phase of formation (evolutionary experimentation). Hormesis, by transformation (fixation) of cytoplasmic receptor-like membrane components to receptors in the presence of the given hormone, likely helps the development of unicellular endocrine character and by this the evolution of endocrine system. The effect by extremely low concentrations of hormones had been forced by the watery way of unicellular life, which could establish the physiological concentrations of hormones in the blood of higher ranked animals. This means that hormetic low doses are the normal, effective concentrations and the high concentrations are artificial, consequently could be dangerous.
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Affiliation(s)
- György Csaba
- 1 Department of Genetics, Cell- and Immunobiology, Semmelweis University, Budapest, Hungary
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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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Fields C, Levin M. Somatic multicellularity as a satisficing solution to the prediction-error minimization problem. Commun Integr Biol 2019; 12:119-132. [PMID: 31413788 PMCID: PMC6682261 DOI: 10.1080/19420889.2019.1643666] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/04/2019] [Accepted: 07/07/2019] [Indexed: 11/26/2022] Open
Abstract
Adaptive success in the biosphere requires the dynamic ability to adjust physiological, transcriptional, and behavioral responses to environmental conditions. From chemical networks to organisms to whole communities, biological entities at all levels of organization seek to optimize their predictive power. Here, we argue that this fundamental drive provides a novel perspective on the origin of multicellularity. One way for unicellular organisms to minimize surprise with respect to external inputs is to be surrounded by reproductively-disabled, i.e. somatic copies of themselves – highly predictable agents which in effect reduce uncertainty in their microenvironments. We show that the transition to multicellularity can be modeled as a phase transition driven by environmental threats. We present modeling results showing how multicellular bodies can arise if non-reproductive somatic cells protect their reproductive parents from environmental lethality. We discuss how a somatic body can be interpreted as a Markov blanket around one or more reproductive cells, and how the transition to somatic multicellularity can be represented as a transition from exposure of reproductive cells to a high-uncertainty environment to their protection from environmental uncertainty by this Markov blanket. This is, effectively, a transition by the Markov blanket from transparency to opacity for the variational free energy of the environment. We suggest that the ability to arrest the cell cycle of daughter cells and redirect their resource utilization from division to environmental threat amelioration is the key innovation of obligate multicellular eukaryotes, that the nervous system evolved to exercise this control over long distances, and that cancer is an escape by somatic cells from the control of reproductive cells. Our quantitative model illustrates the evolutionary dynamics of this system, provides a novel hypothesis for the origin of multicellular animal bodies, and suggests a fundamental link between the architectures of complex organisms and information processing in proto-cognitive cellular agents.
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Affiliation(s)
| | - Michael Levin
- Allen Discovery Center at Tufts University, Medford, MA USA
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10
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Abstract
The hormesis concept demonstrates that in contrast to the toxic effect of high doses of materials, irradiation, etc., low doses of them are beneficial and, in addition, help to eliminate (prevent) the deleterious effect of high doses given after it. By this effect, it is an important factor of (human) evolution protecting man from harmful impacts, similarly to the role of immunity. However, immunity is also continuously influenced by hormetic effects of environmental [chemical (pollutions), physical (background irradiations and heat), etc.] and medical (drugs and therapeutic irradiations) and food interactions. In contrast to earlier beliefs, the no-threshold irradiation dogma is not valid in low-dose domains and here the hormesis concept is valid. Low-dose therapeutic irradiation, as well as background irradiations (by radon spas or moderately far from the epicenter of atomic bomb or nuclear facilities), is rather beneficial than destructive and the fear from them seems to be unreasonable from immunological point of view. Practically, all immune parameters are beneficially influenced by all forms of low-dose radiations.
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Affiliation(s)
- György Csaba
- 1 Department of Genetics, Cell- and Immunobiology, Semmelweis University, Budapest, Hungary
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11
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Vitali V, Horn F, Catania F. Insulin-like signaling within and beyond metazoans. Biol Chem 2019; 399:851-857. [PMID: 29664731 DOI: 10.1515/hsz-2018-0135] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 04/04/2018] [Indexed: 12/29/2022]
Abstract
Insulin signaling is pivotal in controlling animals' lifespan and responses to environmental changes and, when altered, it may lead to pathogenic states. Despite its importance and relevance for biomedical research, insulin's mechanism of action and the full range of its pathophysiological effects remain incompletely understood. Likewise, the evolutionary origin of insulin and its associated signaling components are unclear. Notwithstanding the common view that insulin signaling originated within metazoans, experimental evidence from non-metazoans suggest a more widespread distribution across eukaryotes. Here, we summarize this evidence. Furthermore, we put forward an evolutionary account that reconciles seemingly contradictory results in the literature.
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Affiliation(s)
- Valerio Vitali
- Institute for Evolution and Biodiversity, University of Münster, Hüfferstrasse 1, D-48149 Münster, Germany
| | - Florian Horn
- Department of Anatomy, Histology and Embryology, Medical University Innsbruck, Müllerstrasse 59, A-6020 Innsbruck, Austria
| | - Francesco Catania
- Institute for Evolution and Biodiversity, University of Münster, Hüfferstrasse 1, D-48149 Münster, Germany
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12
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Yuan H, Silberstein SD. Histamine and Migraine. Headache 2017; 58:184-193. [PMID: 28862769 DOI: 10.1111/head.13164] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 07/11/2017] [Indexed: 01/10/2023]
Abstract
BACKGROUND Histamine is an ancient "tissue amine" preceding multicellular organisms. In the central nervous system (CNS), its fibers originate solely from the tuberomammillary nucleus and travel throughout the brain. It is mainly responsible for wakefulness, energy homeostasis, and memory consolidation. Recently, several studies suggest a potential role of histamine in migraine pathogenesis and management. METHODS Narrative review of current literature regarding histamine and migraine. RESULTS Histamine plays a crucial role in migraine pathogenesis: sustaining the neurogenic inflammation pathway. Interaction between mast cells (MC) and calcitonin-gene related protein (CGRP) results in sensitization of trigeminal afferents and trigeminal ganglia (TG). Histamine binds with differing affinities to four different histaminergic G-protein coupled receptors, activating protein kinases, or triggering calcium release with subsequent mode of actions. Histamine 1 receptor (H1 R) and histamine 2 receptor (H2 R) antagonists are frequently used for the treatment of allergy and gastric acid secretion, respectively, but their antagonism is probably ineffective for migraine. Histamine 3 receptor (H3 R) and histamine 4 receptor (H4 R) have a threefold higher affinity than H1 R/H2 R for histamine and are found almost exclusively on neurons and immune tissues, respectively. H3 R acts as an autoreceptor or as a heteroreceptor, lowering the release of histamine and other neurotransmitters. This is a potential target for anti-nociception and anti-neurogenic inflammation. To date, several small clinical trials using low dose histamine or Nα -methylhistamine have demonstrated migraine prophylactic efficacy, probably via H3 R or other undetermined pathways. CONCLUSION The histamine system interacts with multiple regions in the CNS and may hypothetically modulate the migraine response. Low dose histamine may be a promising option for migraine prevention.
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Affiliation(s)
- Hsiangkuo Yuan
- Jefferson Headache Center, Thomas Jefferson University, Philadelphia, PA, USA
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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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Romero SA, Hocker AD, Mangum JE, Luttrell MJ, Turnbull DW, Struck AJ, Ely MR, Sieck DC, Dreyer HC, Halliwill JR. Evidence of a broad histamine footprint on the human exercise transcriptome. J Physiol 2016; 594:5009-23. [PMID: 27061420 DOI: 10.1113/jp272177] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 03/30/2016] [Indexed: 02/06/2023] Open
Abstract
KEY POINTS Histamine is a primordial signalling molecule, capable of activating cells in an autocrine or paracrine fashion via specific cell surface receptors, in a variety of pathways that probably predate its more recent role in innate and adaptive immunity. Although histamine is normally associated with pathological conditions or allergic and anaphylactic reactions, it may contribute beneficially to the normal changes that occur within skeletal muscle during the recovery from exercise. We show that the human response to exercise includes an altered expression of thousands of protein-coding genes, and much of this response appears to be driven by histamine. Histamine may be an important molecular transducer contributing to many of the adaptations that accompany chronic exercise training. ABSTRACT Histamine is a primordial signalling molecule, capable of activating cells in an autocrine or paracrine fashion via specific cell surface receptors. In humans, aerobic exercise is followed by a post-exercise activation of histamine H1 and H2 receptors localized to the previously exercised muscle. This could trigger a broad range of cellular adaptations in response to exercise. Thus, we exploited RNA sequencing to explore the effects of H1 and H2 receptor blockade on the exercise transcriptome in human skeletal muscle tissue harvested from the vastus lateralis. We found that exercise exerts a profound influence on the human transcriptome, causing the differential expression of more than 3000 protein-coding genes. The influence of histamine blockade post-exercise was notable for 795 genes that were differentially expressed between the control and blockade condition, which represents >25% of the number responding to exercise. The broad histamine footprint on the human exercise transcriptome crosses many cellular functions, including inflammation, vascular function, metabolism, and cellular maintenance.
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Affiliation(s)
| | | | | | | | | | - Adam J Struck
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, OR, USA
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15
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Ništiar F, Rácz O, Brenišin M. Can imprinting play a role in the response of Tetrahymena pyriformis to toxic substance exposure? ENVIRONMENTAL EPIGENETICS 2016; 2:dvw010. [PMID: 29492290 PMCID: PMC5804524 DOI: 10.1093/eep/dvw010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 06/06/2016] [Accepted: 06/07/2016] [Indexed: 06/08/2023]
Abstract
Among protozoa, Tetrahymena pyriformis is the most commonly ciliated model used for laboratory research. All living organisms need to adapt to ever changing adverse conditions in order to survive. This article focuses on the phenomenon that exposure to toxic doses of the toxicants protects against a normally harmful dose of the same stressor. This first encounter by toxicant provokes the phenomenon of epigenetical imprinting, by which the reaction of the cell is quantitatively modified. This modification is transmitted to the progeny generations. The experiments demonstrate the possibility of epigenetic effects at a unicellular level and call attention to the possibility that the character of unicellular organisms has changed through to the present day due to an enormous amount of non-physiological imprinter substances in their environment. The results point to the validity of epigenetic imprinting effects throughout the animal world. Imprinting in Tetrahymena was likely the first epigenetic phenomenon which was justified at cellular level. It is very useful for the unicellular organisms, as it helps to avoid dangerous molecules more easily or to find useful ones and by this contributes to the permanence of the population's life.
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Affiliation(s)
- František Ništiar
- Department of Pathological Physiology, Faculty of Medicine, P. J. Šafárik University, Košice, Slovak Republic
| | - Oliver Rácz
- Department of Pathological Physiology, Faculty of Medicine, P. J. Šafárik University, Košice, Slovak Republic
| | - Marek Brenišin
- Department of Pathological Physiology, Faculty of Medicine, P. J. Šafárik University, Košice, Slovak Republic
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Harris KD, Barzilai A, Zahavi A. An evolutionary perspective on signaling peptides: toxic peptides are selected to provide information regarding the processing of the propeptide, which represents the phenotypic state of the signaling cell. F1000Res 2015; 4:512. [PMID: 26594342 PMCID: PMC4648229 DOI: 10.12688/f1000research.6874.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/03/2015] [Indexed: 11/23/2022] Open
Abstract
Structurally similar short peptides often serve as signals in diverse signaling systems. Similar peptides affect diverse physiological pathways in different species or even within the same organism. Assuming that signals provide information, and that this information is tested by the structure of the signal, it is curious that highly similar signaling peptides appear to provide information relevant to very different metabolic processes. Here we suggest a solution to this problem: the synthesis of the propeptide, and its post-translational modifications that are required for its cleavage and the production of the mature peptide, provide information on the phenotypic state of the signaling cell. The mature peptide, due to its chemical properties which render it harmful, serves as a stimulant that forces cells to respond to this information. To support this suggestion, we present cases of signaling peptides in which the sequence and structure of the mature peptide is similar yet provides diverse information. The sequence of the propeptide and its post-translational modifications, which represent the phenotypic state of the signaling cell, determine the quantity and specificity of the information. We also speculate on the evolution of signaling peptides. We hope that this perspective will encourage researchers to reevaluate pathological conditions in which the synthesis of the mature peptide is abnormal.
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Affiliation(s)
| | - Ari Barzilai
- Department of Neurobiology, Tel Aviv University, Tel Aviv, 69978, Israel ; Sagol School of Neuroscience, Tel Aviv, 69978, Israel
| | - Amotz Zahavi
- Department of Zoology, Tel-Aviv University, Tel Aviv, 69978, Israel ; Sagol School of Neuroscience, Tel Aviv, 69978, Israel
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Kőhidai L, Tóth K, Samotik P, Ranganathan K, Láng O, Tóth M, Ruskoaho H. Effect of vasoactive peptides in Tetrahymena: chemotactic activities of adrenomedullin, proadrenomedullin N-terminal 20 peptide (PAMP) and calcitonin gene-related peptide (CGRP). Mol Cell Biochem 2015; 411:271-80. [PMID: 26481478 DOI: 10.1007/s11010-015-2589-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 10/08/2015] [Indexed: 11/30/2022]
Abstract
Adrenomedullin (AMD), proadrenomedullin N-terminal 20 peptide (PAMP) and calcitonin gene-related peptide (CGRP) were studied for chemotaxis, chemotactic selection and G-actin/F-actin transition in Tetrahymena. The aim of the experiments was to study the effects of two different peptides encoded by the same gene compared to a peptide related to one of the two, but encoded by a different gene, at a low level of phylogeny. The positive, chemotactic effect of ADM and the strong negative, chemorepellent effect of PAMP suggest that in Tetrahymena, the two peptides elicit their chemotactic effects via different signalling mechanisms. The complexity of swimming behaviour modulated by the three peptides underlines that chemotaxis, chemokinesis and some characteristics of migratory behaviour (velocity, tortuosity) are working as a sub-population level complex functional unit. Chemotactic responsiveness to ADM and CGRP is short-term, in contrast to PAMP, which as a chemorepellent ligand, has the ability to select sub-populations with negative chemotactic responsiveness. The different effects of ADM and PAMP on the polymerization of actin networks show that the microtubular structure of cilia is more essential to chemotactic response than are transitions of the actin network. The results draw attention to the characteristic effects of vasoactive peptides at this low level of phylogeny.
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Affiliation(s)
- László Kőhidai
- Department of Genetics, Cell and Immunobiology, Semmelweis University, Nagyvárad tér 4., Budapest, 1089, Hungary.
| | - Katalin Tóth
- Department of Genetics, Cell and Immunobiology, Semmelweis University, Nagyvárad tér 4., Budapest, 1089, Hungary
| | - Paul Samotik
- Department of Genetics, Cell and Immunobiology, Semmelweis University, Nagyvárad tér 4., Budapest, 1089, Hungary
| | - Kiran Ranganathan
- Department of Genetics, Cell and Immunobiology, Semmelweis University, Nagyvárad tér 4., Budapest, 1089, Hungary
| | - Orsolya Láng
- Department of Genetics, Cell and Immunobiology, Semmelweis University, Nagyvárad tér 4., Budapest, 1089, Hungary
| | - Miklós Tóth
- Department of Health Sciences and Sport Medicine, University of Health Science, Alkotás street 44., Budapest, 1123, Hungary
| | - Heikki Ruskoaho
- Division of Pharmacology and Pharmcotherapy, University of Helsinki, P.O.Box 56, 00014, Helsinki, Finland
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Poklepovich TJ, Urtasun N, Miranda MV, Nusblat AD, Nudel CB. Expression and functional characterization of a C-7 cholesterol desaturase from Tetrahymena thermophila in an insect cell line. Steroids 2015; 96:132-9. [PMID: 25681633 DOI: 10.1016/j.steroids.2015.02.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 01/22/2015] [Accepted: 02/02/2015] [Indexed: 01/18/2023]
Abstract
Tetrahymena thermophila transforms exogenous cholesterol into pro-vitamin D3 (7-dehydrocholesterol) with remarkable efficiency in a one-step reaction carried out by a C-7 cholesterol desaturase. The enzyme DES7 is encoded by the gene TTHERM_00310640, identified with RNAi and gene knock-out experiments, but has not yet been heterologously expressed actively in any organism. A model derived from its amino acid sequence classified DES7p as a Rieske-type oxygenase with transmembrane localization. The protein has catalytic activity, sequence and topological similarity to DAF-36/Neverland proteins involved in the synthesis of steroid hormones in insects and nematodes. Due to their structural and functional similarity, we analyzed the expression of a codon optimized DES7 gene from Tetrahymena in the insect Sf9 cell line, identified and measured the steroid metabolites formed, and extended the actual knowledge on its localization. We found that the accumulation of 7-dehydrocholesterol could be increased 16-40-fold in Spodopterafrugiperda, depending on physiological conditions, by overexpression of T. thermophila DES7. The protein was detected in the microsomal fraction, in accordance with previous reports. Although the electron transfer chain for Des7p/DAF-36/Neverland Rieske-type oxygenases is presently unknown, we identified possible donors in the ciliate and insect genomes by bioinformatic analysis. In spite of the large evolutionary distance between S. frugiperda and T. thermophila, the results indicate that there is significant functional conservation of the electron donors, since the ciliate's sterol desaturase can function in the context of the insect electron transport system. The results achieved demonstrate that DES7 is the first gene from a ciliate, coding for a microsomal enzyme, expressed in active form in an insect cell line.
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Affiliation(s)
- Tomas J Poklepovich
- Instituto de Nanobiotecnología NANOBIOTEC, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, (C1113AAD) Buenos Aires, Argentina
| | - Nicolás Urtasun
- Instituto de Nanobiotecnología NANOBIOTEC, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, (C1113AAD) Buenos Aires, Argentina
| | - María V Miranda
- Instituto de Nanobiotecnología NANOBIOTEC, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, (C1113AAD) Buenos Aires, Argentina
| | - Alejandro D Nusblat
- Instituto de Nanobiotecnología NANOBIOTEC, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, (C1113AAD) Buenos Aires, Argentina.
| | - Clara B Nudel
- Instituto de Nanobiotecnología NANOBIOTEC, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, (C1113AAD) Buenos Aires, Argentina
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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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20
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Csaba G. Hormones in the immune system and their possible role. A critical review. Acta Microbiol Immunol Hung 2014; 61:241-60. [PMID: 25261940 DOI: 10.1556/amicr.61.2014.3.1] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Immune cells synthesize, store and secrete hormones, which are identical with the hormones of the endocrine glands. These are: the POMC hormones (ACTH, endorphin), the thyroid system hormones (TRH, TSH, T3), growth hormone (GH), prolactin, melatonin, histamine, serotonin, catecholamines, GnRH, LHRH, hCG, renin, VIP, ANG II. This means that the immune cells contain all of the hormones, which were searched at all and they also have receptors for these hormones. From this point of view the immune cells are similar to the unicells (Tetrahymena), so it can be supposed that these cells retained the properties characteristic at a low level of phylogeny while other cells during the evolution accumulated to form endocrine glands. In contrast to the glandular endocrine cells, immune cells are polyproducers and polyreceivers. As they are mobile cells, they are able to transport the stored hormone to different places (packed transport) or attracted by local factors, accumulate in the neighborhood of the target, synthesizing and secreting hormones locally. This is taking place, e.g. in the case of endorphin, where the accumulating immune cells calms pain caused by the inflammation. The targeted packed transport is more economical than the hormone-pouring to the blood circulation of glandular endocrines and the targeting also cares the other receptor-bearing cells timely not needed the effect. Mostly the immune-effects of immune-cell derived hormones were studied (except endorphin), however, it is not exactly cleared, while the system could have scarcely studied important roles in other cases. The evolutionary aspects and the known as well, as possible roles of immune-endocrine system and their hormones are listed and discussed.
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Affiliation(s)
- György Csaba
- 1 Semmelweis University Department of Genetics, Cell and Immunobiology Budapest Hungary
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21
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Harris KD, Weiss M, Zahavi A. Why are neurotransmitters neurotoxic? An evolutionary perspective. F1000Res 2014; 3:179. [PMID: 25580225 PMCID: PMC4288432 DOI: 10.12688/f1000research.4828.2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/01/2014] [Indexed: 02/02/2023] Open
Abstract
In the CNS, minor changes in the concentration of neurotransmitters such as glutamate or dopamine can lead to neurodegenerative diseases. We present an evolutionary perspective on the function of neurotransmitter toxicity in the CNS. We hypothesize that neurotransmitters are selected because of their toxicity, which serves as a test of neuron quality and facilitates the selection of neuronal pathways. This perspective may offer additional explanations for the reduction of neurotransmitter concentration in the CNS with age, and suggest an additional role for the blood-brain barrier. It may also suggest a connection between the specific toxicity of the neurotransmitters released in a specific region of the CNS, and elucidate their role as chemicals that are optimal for testing the quality of cells in that region.
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Affiliation(s)
- Keith D Harris
- Department of Zoology, Tel-Aviv University, Tel Aviv, 69978, Israel
| | - Meital Weiss
- Department of Zoology, Tel-Aviv University, Tel Aviv, 69978, Israel
| | - Amotz Zahavi
- Department of Zoology, Tel-Aviv University, Tel Aviv, 69978, Israel ; Sagol School of Neuroscience, Tel-Aviv University, Tel Aviv, 69978, Israel
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Nociceptin Signaling Involves a Calcium-Based Depolarization in Tetrahymena thermophila. INTERNATIONAL JOURNAL OF PEPTIDES 2013; 2013:573716. [PMID: 23737806 PMCID: PMC3657412 DOI: 10.1155/2013/573716] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Accepted: 04/09/2013] [Indexed: 11/18/2022]
Abstract
Tetrahymena thermophila are free-living, ciliated eukaryotes. Their behavioral response to stimuli is well characterized and easily observable, since cells swim toward chemoattractants and avoid chemorepellents. Chemoattractant responses involve increased swim speed or a decreased change in swim direction, while chemorepellent signaling involves ciliary reversal, which causes the organism to jerk back and forth, swim in small circles, or spin in an attempt to get away from the repellent. Many food sources, such as proteins, are chemoattractants for these organisms, while a variety of compounds are repellents. Repellents in nature are thought to come from the secretions of predators or from ruptured organisms, which may serve as “danger” signals. Interestingly, several peptides involved in vertebrate pain signaling are chemorepellents in Tetrahymena, including substances P, ACTH, PACAP, VIP, and nociceptin. Here, we characterize the response of Tetrahymena thermophila to three different isoforms of nociceptin. We find that G-protein inhibitors and tyrosine kinase inhibitors do not affect nociceptin avoidance. However, the calcium chelator, EGTA, and the SERCA calcium ATPase inhibitor, thapsigargin, both inhibit nociceptin avoidance, implicating calcium in avoidance. This result is confirmed by electrophysiology studies which show that 50 μM nociceptin-NH2 causes a sustained depolarization of approximately 40 mV, which is eliminated by the addition of extracellular EGTA.
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23
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Najle SR, Nusblat AD, Nudel CB, Uttaro AD. The Sterol-C7 desaturase from the ciliate Tetrahymena thermophila is a Rieske Oxygenase, which is highly conserved in animals. Mol Biol Evol 2013; 30:1630-43. [PMID: 23603937 DOI: 10.1093/molbev/mst076] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The ciliate Tetrahymena thermophila incorporates sterols from its environment that desaturates at positions C5(6), C7(8), and C22(23). Phytosterols are additionally modified by removal of the ethyl group at carbon 24 (C24). The enzymes involved are oxygen-, NAD(P)H-, and cytochrome b5 dependent, reason why they were classified as members of the hydroxylases/desaturases superfamily. The ciliate's genome revealed the presence of seven putative sterol desaturases belonging to this family, two of which we have previously characterized as the C24-de-ethylase and C5(6)-desaturase. A Rieske oxygenase was also identified; this type of enzyme, with sterol C7(8)-desaturase activity, was observed only in animals, called Neverland in insects and DAF-36 in nematodes. They perform the conversion of cholesterol into 7-dehydrocholesterol, first step in the synthesis of the essential hormones ecdysteroids and dafachronic acids. By adapting an RNA interference-by-feeding protocol, we easily screened six of the eight genes described earlier, allowing the characterization of the Rieske-like oxygenase as the ciliate's C7(8)-desaturase (Des7p). This characterization was confirmed by obtaining the corresponding knockout mutant, making Des7p the first nonanimal Rieske-sterol desaturase described. To our knowledge, this is the first time that the feeding-RNAi technique was successfully applied in T. thermophila, enabling to consider such methodology for future reverse genetics high-throughput screenings in this ciliate. Bioinformatics analyses revealed the presence of Des7p orthologs in other Oligohymenophorean ciliates and in nonanimal Opisthokonts, like the protists Salpingoeca rosetta and Capsaspora owczarzaki. A horizontal gene transfer event from a unicellular Opisthokont to an ancient phagotrophic Oligohymenophorean could explain the acquisition of the Rieske oxygenase by Tetrahymena.
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Affiliation(s)
- Sebastián R Najle
- Instituto de Biología Molecular y Celular de Rosario, CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
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24
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Csaba G. Insulin at a unicellular eukaryote level. Cell Biol Int 2013; 37:267-75. [DOI: 10.1002/cbin.10054] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 01/11/2013] [Indexed: 11/09/2022]
Affiliation(s)
- György Csaba
- Department of Genetics, Cell and Immunobiology; Semmelweis University; Budapest; Hungary
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25
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Lajkó E, Szabó I, Andódy K, Pungor A, Mező G, Kőhidai L. Investigation on chemotactic drug targeting (chemotaxis and adhesion) inducer effect of GnRH-III derivatives in Tetrahymena and human leukemia cell line. J Pept Sci 2012. [PMID: 23208929 DOI: 10.1002/psc.2472] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
GnRH-III has been shown to exert a cytotoxic effect on the GnRH-R positive tumor cells. The chemotactic drug targeting (CDT) represents a new way for drug delivery approach based on selective chemoattractant guided targeting. The major goal of the present work was to develop and investigate various GnRH-III derivatives as potential targeting moieties for CDT. The cell physiological effects (chemotaxis, adhesion, and signaling) induced by three native GnRHs (hGnRH-I, cGnRH-II, and lGnRH-III) and nine GnRH-III derivatives were evaluated in two model cells (Tetrahymena pyriformis and Mono Mac 6 human monocytes). According to our results, the native GnRH-III elicited the highest chemoattractant and adhesion inducer activities of all synthesized peptides in micromolar concentrations in monocytes. With respect to chemoattraction, dimeric derivatives linked by a disulfide bridge ([GnRH-III(C)](2) ) proved to be efficient in both model cells; furthermore, acetylation of the linker region ([GnRH-III(Ac-C)](2) ) could slightly improve the chemotactic and adhesion effects in monocytes. The length of the peptide and the type of N-terminal amino acid could also determine the chemotactic and adhesion modulation potency of each fragment. The application of the chemoattractant GnRH-III derivatives was accompanied by a significant activation of phosphatidylinositol 3-kinase in both model cells. In summary, our work on low-level differentiated model cells of tumors has proved that GnRH-III and some of its synthetic derivatives are promising candidates to be applied in CDT: these compounds might act both as carrier, delivery unit, and antitumor agents.
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Affiliation(s)
- Eszter Lajkó
- Department of Genetics Cell and Immunobiology, Semmelweis University, Nagyvárad tér. 4, H-1089, Budapest, Hungary
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Lajkó E, Pállinger É, Csaba G. Effect of glucose on the insulin production and insulin binding of Tetrahymena. Acta Microbiol Immunol Hung 2012. [PMID: 23195554 DOI: 10.1556/amicr.59.2012.4.3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
As the unicellular ciliate, Tetrahymena has insulin receptors and produces insulin itself, which can regulate its glucose metabolism and other cell functions, in the present experiments the feed-back, the effect of glucose on the insulin binding and insulin production was studied. The cells were kept partly in tryptone-yeast medium, partly in Losina salt solution. The duration of treatment (in 0.1, 1.0, 10.0 mg/ml glucose) in the binding study was 10 min, in the hormone production study 30 min. FITC-insulin binding was significantly decreased only by 0.1 mg/ml glucose treatment in medium and by 10 mg/ml glucose in salt. The insulin production was significantly lower only in cells treated with 10 mg/ml glucose in medium. The insulin binding in salt was always higher and the insulin production always lower, than in medium. Earlier results demonstrated that the hormonal system (presence of hormones, receptors and signal pathways) of higher ranked animals can be deduced to a unicellular level, however, the feed-back mechanism is not really present here, only the traces can be observed in these protozoa.
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Affiliation(s)
- Eszter Lajkó
- 1 Semmelweis University Department of Genetics, Cell and Immunobiology Budapest Hungary
| | - Éva Pállinger
- 2 Research Group for Inflammation Biology and Immunogenomics of Hungarian Academy of Sciences and Semmelweis University Budapest Hungary
| | - G. Csaba
- 1 Semmelweis University Department of Genetics, Cell and Immunobiology Budapest Hungary
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27
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Csaba G. Hormonal imprinting in the unicellular Tetrahymena: the proto-model of epigenetics. Acta Microbiol Immunol Hung 2012; 59:291-310. [PMID: 22982634 DOI: 10.1556/amicr.59.2012.3.1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The unicellular ciliate, Tetrahymena has a complete hormonal system. It has receptors for receiving hormones, produces, stores and secretes hormones, similar to mammalian ones and has signal transduction pathways, for transmitting the information given by the hormones. The first encounter with a hormone provokes the hormonal imprinting under the effect of which the further encounters with the same hormone induces altered (usually enhanced) reaction (hormone binding, hormone synthesis, chemoattraction, movement, growth etc.). The effect of imprinting is durable, it can be observed also after 1000 generations, or after one year in non-dividing cells. Receptors of the nuclear envelope also can be imprinted. The plasma membrane receptors provoked by imprinting are similar to the receptors of mammals. Although steroid hormones are not present in Tetrahymena, the production of them and their receptors can be induced by imprinting. The hormonal imprinting is an epigenetic process and inhibition of DNA-methylation alters the imprinting. Hormonal imprinting in Tetrahymena was likely the first epigenetic phenomenon which was justified at cellular level. It is very useful for the unicells, as it helps to avoid dangerous molecules more easily or to find useful ones and by this contributes to the permanence of the population's life.
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Affiliation(s)
- György Csaba
- 1 Semmelweis University Department of Genetics, Cell and Immunobiology Budapest Hungary
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