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Häder DP, Hemmersbach R. Euglena, a Gravitactic Flagellate of Multiple Usages. Life (Basel) 2022; 12:1522. [PMID: 36294957 PMCID: PMC9605500 DOI: 10.3390/life12101522] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 09/19/2022] [Accepted: 09/21/2022] [Indexed: 11/29/2022] Open
Abstract
Human exploration of space and other celestial bodies bears a multitude of challenges. The Earth-bound supply of material and food is restricted, and in situ resource utilisation (ISRU) is a prerequisite. Excellent candidates for delivering several services are unicellular algae, such as the space-approved flagellate Euglena gracilis. This review summarizes the main characteristics of this unicellular organism. Euglena has been exposed on various platforms that alter the impact of gravity to analyse its corresponding gravity-dependent physiological and molecular genetic responses. The sensory transduction chain of gravitaxis in E. gracilis has been identified. The molecular gravi-(mechano-)receptors are mechanosensory calcium channels (TRP channels). The inward gated calcium binds specifically to one of several calmodulins (CaM.2), which, in turn, activates an adenylyl cyclase. This enzyme uses ATP to produce cAMP, which induces protein kinase A, followed by the phosphorylation of a motor protein in the flagellum, initiating a course correction, and, finally, resulting in gravitaxis. During long space missions, a considerable amount of food, oxygen, and water has to be carried, and the exhaled carbon dioxide has to be removed. In this context, E. gracilis is an excellent candidate for biological life support systems, since it produces oxygen by photosynthesis, takes up carbon dioxide, and is even edible. Various species and mutants of Euglena are utilized as a producer of commercial food items, as well as a source of medicines, as it produces a number of vitamins, contains numerous trace elements, and synthesizes dietary proteins, lipids, and the reserve molecule paramylon. Euglena has anti-inflammatory, -oxidant, and -obesity properties.
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Affiliation(s)
- Donat-P. Häder
- Department of Botany, Emeritus from Friedrich-Alexander University, 91096 Erlangen, Germany
| | - Ruth Hemmersbach
- German Aerospace Center, Institute of Aerospace Medicine, Gravitational Biology, Linder Hoehe, 51147 Cologne, Germany
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Molecular Cross-Talk between Gravity- and Light-Sensing Mechanisms in Euglena gracilis. Int J Mol Sci 2022; 23:ijms23052776. [PMID: 35269918 PMCID: PMC8911436 DOI: 10.3390/ijms23052776] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 02/19/2022] [Accepted: 03/01/2022] [Indexed: 12/14/2022] Open
Abstract
Euglena gracilis is a photosynthetic flagellate. To acquire a suitable position in its surrounding aquatic environment, it exploits light and gravity primarily as environmental cues. Several physiological studies have indicated a fine-tuned relationship between gravity sensing (gravitaxis) and light sensing in E. gracilis. However, the underlying molecular mechanism is largely unknown. The photoreceptor photoactivated adenylyl cyclase (PAC) has been studied for over a decade. Nevertheless, no direct/indirect interaction partner (upstream/downstream) has been reported for PAC. It has been shown that a specific protein, kinase A (PKA), showed to be involved in phototaxis and gravitaxis. The current study reports the localization of the specific PKA and its relationship with PAC.
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Häder DP, Hemmersbach R. Gravitaxis in Euglena. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 979:237-266. [DOI: 10.1007/978-3-319-54910-1_12] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Häder DP, Iseki M. Photomovement in Euglena. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 979:207-235. [DOI: 10.1007/978-3-319-54910-1_11] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Phan TX, Jaruga B, Pingle SC, Bandyopadhyay BC, Ahern GP. Intrinsic Photosensitivity Enhances Motility of T Lymphocytes. Sci Rep 2016; 6:39479. [PMID: 27995987 PMCID: PMC5171715 DOI: 10.1038/srep39479] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 11/23/2016] [Indexed: 01/17/2023] Open
Abstract
Sunlight has important biological effects in human skin. Ultraviolet (UV) light striking the epidermis catalyzes the synthesis of Vitamin D and triggers melanin production. Although a causative element in skin cancers, sunlight is also associated with positive health outcomes including reduced incidences of autoimmune diseases and cancers. The mechanisms, however, by which light affects immune function remain unclear. Here we describe direct photon sensing in human and mouse T lymphocytes, a cell-type highly abundant in skin. Blue light irradiation at low doses (<300 mJ cm-2) triggers synthesis of hydrogen peroxide (H2O2) in T cells revealed by the genetically encoded reporter HyPerRed. In turn, H2O2 activates a Src kinase/phospholipase C-γ1 (PLC-γ1) signaling pathway and Ca2+ mobilization. Pharmacologic inhibition or genetic disruption of Lck kinase, PLC-γ1 or the T cell receptor complex inhibits light-evoked Ca2+ transients. Notably, both light and H2O2 enhance T-cell motility in a Lck-dependent manner. Thus, T lymphocytes possess intrinsic photosensitivity and this property may enhance their motility in skin.
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Affiliation(s)
- Thieu X Phan
- Department of Pharmacology and Physiology, Georgetown University Medical Center, 3900 Reservoir Road, NW, Washington DC, 20007, USA.,Department of Biology, Vinh University, Vinh City, Vietnam
| | - Barbara Jaruga
- Department of Pharmacology and Physiology, Georgetown University Medical Center, 3900 Reservoir Road, NW, Washington DC, 20007, USA
| | - Sandeep C Pingle
- Department of Pharmacology and Physiology, Georgetown University Medical Center, 3900 Reservoir Road, NW, Washington DC, 20007, USA
| | - Bidhan C Bandyopadhyay
- Department of Pharmacology and Physiology, Georgetown University Medical Center, 3900 Reservoir Road, NW, Washington DC, 20007, USA.,Research Service, Veterans Affairs Medical Center, Washington, DC 20422, USA
| | - Gerard P Ahern
- Department of Pharmacology and Physiology, Georgetown University Medical Center, 3900 Reservoir Road, NW, Washington DC, 20007, USA
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Light and the evolution of vision. Eye (Lond) 2015; 30:173-8. [PMID: 26541087 DOI: 10.1038/eye.2015.220] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 09/22/2015] [Indexed: 01/09/2023] Open
Abstract
It might seem a little ridiculous to cover the period over which vision evolved, perhaps 1.5 billion years, in only 3000 words. Yet, if we examine the photoreceptor molecules of the most basic eukaryote protists and even before that, in those of prokaryote bacteria and cyanobacteria, we see how similar they are to those of mammalian rod and cone photoreceptor opsins and the photoreceptive molecules of light sensitive ganglion cells. This shows us much with regard the development of vision once these proteins existed, but there is much more to discover about the evolution of even more primitive vision systems.
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Davidi L, Shimoni E, Khozin-Goldberg I, Zamir A, Pick U. Origin of β-carotene-rich plastoglobuli in Dunaliella bardawil. PLANT PHYSIOLOGY 2014; 164:2139-56. [PMID: 24567188 PMCID: PMC3982768 DOI: 10.1104/pp.113.235119] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2014] [Accepted: 02/20/2014] [Indexed: 05/17/2023]
Abstract
The halotolerant microalgae Dunaliella bardawil accumulates under nitrogen deprivation two types of lipid droplets: plastoglobuli rich in β-carotene (βC-plastoglobuli) and cytoplasmatic lipid droplets (CLDs). We describe the isolation, composition, and origin of these lipid droplets. Plastoglobuli contain β-carotene, phytoene, and galactolipids missing in CLDs. The two preparations contain different lipid-associated proteins: major lipid droplet protein in CLD and the Prorich carotene globule protein in βC-plastoglobuli. The compositions of triglyceride (TAG) molecular species, total fatty acids, and sn-1+3 and sn-2 positions in the two lipid pools are similar, except for a small increase in palmitic acid in plastoglobuli, suggesting a common origin. The formation of CLD TAG precedes that of βC-plastoglobuli, reaching a maximum after 48 h of nitrogen deprivation and then decreasing. Palmitic acid incorporation kinetics indicated that, at early stages of nitrogen deprivation, CLD TAG is synthesized mostly from newly formed fatty acids, whereas in βC-plastoglobuli, a large part of TAG is produced from fatty acids of preformed membrane lipids. Electron microscopic analyses revealed that CLDs adhere to chloroplast envelope membranes concomitant with appearance of small βC-plastoglobuli within the chloroplast. Based on these results, we propose that CLDs in D. bardawil are produced in the endoplasmatic reticulum, whereas βC-plastoglobuli are made, in part, from hydrolysis of chloroplast membrane lipids and in part, by a continual transfer of TAG or fatty acids derived from CLD.
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Independent localization of plasma membrane and chloroplast components during eyespot assembly. EUKARYOTIC CELL 2013; 12:1258-70. [PMID: 23873865 DOI: 10.1128/ec.00111-13] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Like many algae, Chlamydomonas reinhardtii is phototactic, using two anterior flagella to swim toward light optimal for photosynthesis. The flagella are responsive to signals initiated at the photosensory eyespot, which comprises photoreceptors in the plasma membrane and layers of pigment granules in the chloroplast. Phototaxis depends on placement of the eyespot at a specific asymmetric location relative to the flagella, basal bodies, and bundles of two or four highly acetylated microtubules, termed rootlets, which extend from the basal bodies toward the posterior of the cell. Previous work has shown that the eyespot is disassembled prior to cell division, and new eyespots are assembled in daughter cells adjacent to the nascent four-membered rootlet associated with the daughter basal body (D4), but the chronology of these assembly events has not been determined. Here we use immunofluorescence microscopy to follow assembly and acetylation of the D4 rootlet, localization of individual eyespot components in the plasma membrane or chloroplast envelope, and flagellar emergence during and immediately following cell division. We find that the D4 rootlet is assembled before the initiation of eyespot assembly, which occurs within the same time frame as rootlet acetylation and flagellar outgrowth. Photoreceptors in the plasma membrane are correctly localized in eyespot mutant cells lacking pigment granule layers, and chloroplast components of the eyespot assemble in mutant cells in which photoreceptor localization is retarded. The data suggest that plasma membrane and chloroplast components of the eyespot are independently responsive to a cytoskeletal positioning cue.
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Ueki N, Matsunaga S, Inouye I, Hallmann A. How 5000 independent rowers coordinate their strokes in order to row into the sunlight: phototaxis in the multicellular green alga Volvox. BMC Biol 2010; 8:103. [PMID: 20663212 PMCID: PMC2920248 DOI: 10.1186/1741-7007-8-103] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Accepted: 07/27/2010] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND The evolution of multicellular motile organisms from unicellular ancestors required the utilization of previously evolved tactic behavior in a multicellular context. Volvocine green algae are uniquely suited for studying tactic responses during the transition to multicellularity because they range in complexity from unicellular to multicellular genera. Phototactic responses are essential for these flagellates because they need to orientate themselves to receive sufficient light for photosynthesis, but how does a multicellular organism accomplish phototaxis without any known direct communication among cells? Several aspects of the photoresponse have previously been analyzed in volvocine algae, particularly in the unicellular alga Chlamydomonas. RESULTS In this study, the phototactic behavior in the spheroidal, multicellular volvocine green alga Volvox rousseletii (Volvocales, Chlorophyta) was analyzed. In response to light stimuli, not only did the flagella waveform and beat frequency change, but the effective stroke was reversed. Moreover, there was a photoresponse gradient from the anterior to the posterior pole of the spheroid, and only cells of the anterior hemisphere showed an effective response. The latter caused a reverse of the fluid flow that was confined to the anterior hemisphere. The responsiveness to light is consistent with an anterior-to-posterior size gradient of eyespots. At the posterior pole, the eyespots are tiny or absent, making the corresponding cells appear to be blind. Pulsed light stimulation of an immobilized spheroid was used to simulate the light fluctuation experienced by a rotating spheroid during phototaxis. The results demonstrated that in free-swimming spheroids, only those cells of the anterior hemisphere that face toward the light source reverse the beating direction in the presence of illumination; this behavior results in phototactic turning. Moreover, positive phototaxis is facilitated by gravitational forces. Under our conditions, V. rousseletii spheroids showed no negative phototaxis. CONCLUSIONS On the basis of our results, we developed a mechanistic model that predicts the phototactic behavior in V. rousseletii. The model involves photoresponses, periodically changing light conditions, morphological polarity, rotation of the spheroid, two modes of flagellar beating, and the impact of gravity. Our results also indicate how recently evolved multicellular organisms adapted the phototactic capabilities of their unicellular ancestors to multicellular life.
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Affiliation(s)
- Noriko Ueki
- Department of Cellular and Developmental Biology of Plants, University of Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany
- Institute of Biological Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8577 Japan
| | - Shigeru Matsunaga
- Institute of Biological Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8577 Japan
- The Promotion Center for Research and Education, Graduate University for Advanced Studies (Sokendai), Hayama, Kanagawa, 240-0193 Japan
| | - Isao Inouye
- Institute of Biological Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8577 Japan
| | - Armin Hallmann
- Department of Cellular and Developmental Biology of Plants, University of Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany
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