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Abstract
Beneficial symbiotic associations, ubiquitously found in nature, have led to the emergence of eukaryotic cells, the bacteriocytes, specialized in harboring microbial partners. One of the most fundamental questions concerning these enigmatic cells is how organismal homeostasis controls their elimination. Here we report that aphid bacteriocytes have evolved a form of cell death distinct from the conserved cell-death mechanisms hitherto characterized. This cell-death mechanism is a nonapoptotic multistep process that starts with the hypervacuolation of the endoplasmic reticulum, followed by a cascade of cellular stress responses. Our findings provide a framework to study biological functioning of bacteriocytes and the cellular mechanisms associated with symbiosis and contribute to the understanding of eukaryotic cell-death diversity. Symbiotic associations play a pivotal role in multicellular life by facilitating acquisition of new traits and expanding the ecological capabilities of organisms. In insects that are obligatorily dependent on intracellular bacterial symbionts, novel host cells (bacteriocytes) or organs (bacteriomes) have evolved for harboring beneficial microbial partners. The processes regulating the cellular life cycle of these endosymbiont-bearing cells, such as the cell-death mechanisms controlling their fate and elimination in response to host physiology, are fundamental questions in the biology of symbiosis. Here we report the discovery of a cell-death process involved in the degeneration of bacteriocytes in the hemipteran insect Acyrthosiphon pisum. This process is activated progressively throughout aphid adulthood and exhibits morphological features distinct from known cell-death pathways. By combining electron microscopy, immunohistochemistry, and molecular analyses, we demonstrated that the initial event of bacteriocyte cell death is the cytoplasmic accumulation of nonautophagic vacuoles, followed by a sequence of cellular stress responses including the formation of autophagosomes in intervacuolar spaces, activation of reactive oxygen species, and Buchnera endosymbiont degradation by the lysosomal system. We showed that this multistep cell-death process originates from the endoplasmic reticulum, an organelle exhibiting a unique reticular network organization spread throughout the entire cytoplasm and surrounding Buchnera aphidicola endosymbionts. Our findings provide insights into the cellular and molecular processes that coordinate eukaryotic host and endosymbiont homeostasis and death in a symbiotic system and shed light on previously unknown aspects of bacteriocyte biological functioning.
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Dani V, Priouzeau F, Mertz M, Mondin M, Pagnotta S, Lacas-Gervais S, Davy SK, Sabourault C. Expression patterns of sterol transporters NPC1 and NPC2 in the cnidarian-dinoflagellate symbiosis. Cell Microbiol 2017; 19. [DOI: 10.1111/cmi.12753] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Revised: 05/16/2017] [Accepted: 05/18/2017] [Indexed: 12/13/2022]
Affiliation(s)
- Vincent Dani
- Institut de Biologie Valrose (iBV); Université Côte d'Azur; Nice France
- UMR7138, Equipe Symbiose Marine; Université Côte d'Azur; Nice France
| | - Fabrice Priouzeau
- Institut de Biologie Valrose (iBV); Université Côte d'Azur; Nice France
- UMR7138, Equipe Symbiose Marine; Université Côte d'Azur; Nice France
| | - Marjolijn Mertz
- Institut de Biologie Valrose (iBV); Université Côte d'Azur; Nice France
| | - Magali Mondin
- Institut de Biologie Valrose (iBV); Université Côte d'Azur; Nice France
| | - Sophie Pagnotta
- Centre Commun de Microscopie Appliquée; Université Côte d'Azur; Nice France
| | | | - Simon K. Davy
- School of Biological Sciences; Victoria University of Wellington; Wellington New Zealand
| | - Cécile Sabourault
- Institut de Biologie Valrose (iBV); Université Côte d'Azur; Nice France
- UMR7138, Equipe Symbiose Marine; Université Côte d'Azur; Nice France
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Chen WNU, Hsiao YJ, Mayfield AB, Young R, Hsu LL, Peng SE. Transmission of a heterologous clade C Symbiodinium in a model anemone infection system via asexual reproduction. PeerJ 2016; 4:e2358. [PMID: 27635330 PMCID: PMC5012276 DOI: 10.7717/peerj.2358] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Accepted: 07/22/2016] [Indexed: 12/15/2022] Open
Abstract
Anemones of genus Exaiptasia are used as model organisms for the study of cnidarian-dinoflagellate (genus Symbiodinium) endosymbiosis. However, while most reef-building corals harbor Symbiodinium of clade C, Exaiptasia spp. anemones mainly harbor clade B Symbiodinium (ITS2 type B1) populations. In this study, we reveal for the first time that bleached Exaiptasia pallida anemones can establish a symbiotic relationship with a clade C Symbiodinium (ITS2 type C1). We further found that anemones can transmit the exogenously supplied clade C Symbiodinium cells to their offspring by asexual reproduction (pedal laceration). In order to corroborate the establishment of stable symbiosis, we used microscopic techniques and genetic analyses to examine several generations of anemones, and the results of these endeavors confirmed the sustainability of the system. These findings provide a framework for understanding the differences in infection dynamics between homologous and heterologous dinoflagellate types using a model anemone infection system.
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Affiliation(s)
- Wan-Nan U. Chen
- Department of Biological Science and Technology, I-Shou University, Kaohsiung, Taiwan
| | - Ya-Ju Hsiao
- National Museum of Marine Biology and Aquarium, Checheng, Pingtung, Taiwan
| | - Anderson B. Mayfield
- National Museum of Marine Biology and Aquarium, Checheng, Pingtung, Taiwan
- Living Oceans Foundation, Landover, MD, United States of America
| | - Ryan Young
- University of California, Davis, United States
| | - Ling-Lan Hsu
- Department of Life Science, National Taiwan University, Taipei, Taiwan
| | - Shao-En Peng
- National Museum of Marine Biology and Aquarium, Checheng, Pingtung, Taiwan
- Graduate Institute of Marine Biology, National Dong Hwa University, Checheng, Pingtung, Taiwan
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Mohamed AR, Cumbo V, Harii S, Shinzato C, Chan CX, Ragan MA, Bourne DG, Willis BL, Ball EE, Satoh N, Miller DJ. The transcriptomic response of the coral
Acropora digitifera
to a competent
Symbiodinium
strain: the symbiosome as an arrested early phagosome. Mol Ecol 2016; 25:3127-41. [DOI: 10.1111/mec.13659] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 04/04/2016] [Accepted: 04/14/2016] [Indexed: 12/15/2022]
Affiliation(s)
- A. R. Mohamed
- ARC Centre of Excellence for Coral Reef Studies James Cook University Townsville Qld 4811 Australia
- Comparative Genomics Centre and Department of Molecular and Cell Biology James Cook University Townsville Qld 4811 Australia
- Zoology Department Faculty of Science Benha University Benha 13518 Egypt
- AIMS@JCU Department of Molecular and Cell Biology Australian Institute of Marine Science James Cook University Townsville Qld 4811 Australia
| | - V. Cumbo
- ARC Centre of Excellence for Coral Reef Studies James Cook University Townsville Qld 4811 Australia
- Department of Biological Sciences Macquarie University Sydney NSW 2109 Australia
| | - S. Harii
- Sesoko Station Tropical Biosphere Research Center University of the Ryukyus 3422 Sesoko Motobu Okinawa 905‐0227 Japan
| | - C. Shinzato
- Marine Genomics Unit Okinawa Institute of Science and Technology Promotion Corporation Onna Okinawa 904‐0412 Japan
| | - C. X. Chan
- ARC Centre of Excellence in Bioinformatics and Institute for Molecular Bioscience The University of Queensland Brisbane Qld 4072 Australia
| | - M. A. Ragan
- ARC Centre of Excellence in Bioinformatics and Institute for Molecular Bioscience The University of Queensland Brisbane Qld 4072 Australia
| | - D. G. Bourne
- Australian Institute for Marine Science PMB 3 Townsville Qld 4811 Australia
| | - B. L. Willis
- ARC Centre of Excellence for Coral Reef Studies James Cook University Townsville Qld 4811 Australia
- Department of Marine Ecosystems and Impacts James Cook University Townsville Qld 4811 Australia
| | - E. E. Ball
- ARC Centre of Excellence for Coral Reef Studies James Cook University Townsville Qld 4811 Australia
- Evolution, Ecology and Genetics Research School of Biology Australian National University Canberra ACT 0200 Australia
| | - N. Satoh
- Marine Genomics Unit Okinawa Institute of Science and Technology Promotion Corporation Onna Okinawa 904‐0412 Japan
| | - D. J. Miller
- ARC Centre of Excellence for Coral Reef Studies James Cook University Townsville Qld 4811 Australia
- Comparative Genomics Centre and Department of Molecular and Cell Biology James Cook University Townsville Qld 4811 Australia
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Abstract
Rab GTPases are at the central node of the machinery that regulates trafficking of organelles, including phagosomes. Thanks to the unique combination of high quality phagosome purification with highly sensitive proteomic studies, the network of Rab proteins that are dynamically associated with phagosomes during the process of maturation of this organelle is relatively well known. Whereas the phagosomal functions of many of the Rab proteins associated with phagosomes are characterized, the role(s) of most of these trafficking regulators remains to be identified. In some cases, even when the function in the context of phagosome biology is described, phagosomal Rab proteins seem to have similar roles. This review summarizes the current knowledge about the identity and function of phagosomal Rab GTPases, with a particular emphasis on new evidence that clarify these seemingly overlapping Rab functions during phagosome maturation.
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Dunlap WC, Starcevic A, Baranasic D, Diminic J, Zucko J, Gacesa R, van Oppen MJH, Hranueli D, Cullum J, Long PF. KEGG orthology-based annotation of the predicted proteome of Acropora digitifera: ZoophyteBase - an open access and searchable database of a coral genome. BMC Genomics 2013; 14:509. [PMID: 23889801 PMCID: PMC3750612 DOI: 10.1186/1471-2164-14-509] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 07/15/2013] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Contemporary coral reef research has firmly established that a genomic approach is urgently needed to better understand the effects of anthropogenic environmental stress and global climate change on coral holobiont interactions. Here we present KEGG orthology-based annotation of the complete genome sequence of the scleractinian coral Acropora digitifera and provide the first comprehensive view of the genome of a reef-building coral by applying advanced bioinformatics. DESCRIPTION Sequences from the KEGG database of protein function were used to construct hidden Markov models. These models were used to search the predicted proteome of A. digitifera to establish complete genomic annotation. The annotated dataset is published in ZoophyteBase, an open access format with different options for searching the data. A particularly useful feature is the ability to use a Google-like search engine that links query words to protein attributes. We present features of the annotation that underpin the molecular structure of key processes of coral physiology that include (1) regulatory proteins of symbiosis, (2) planula and early developmental proteins, (3) neural messengers, receptors and sensory proteins, (4) calcification and Ca2+-signalling proteins, (5) plant-derived proteins, (6) proteins of nitrogen metabolism, (7) DNA repair proteins, (8) stress response proteins, (9) antioxidant and redox-protective proteins, (10) proteins of cellular apoptosis, (11) microbial symbioses and pathogenicity proteins, (12) proteins of viral pathogenicity, (13) toxins and venom, (14) proteins of the chemical defensome and (15) coral epigenetics. CONCLUSIONS We advocate that providing annotation in an open-access searchable database available to the public domain will give an unprecedented foundation to interrogate the fundamental molecular structure and interactions of coral symbiosis and allow critical questions to be addressed at the genomic level based on combined aspects of evolutionary, developmental, metabolic, and environmental perspectives.
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Affiliation(s)
- Walter C Dunlap
- Centre for Marine Microbiology and Genetics, Australian Institute of Marine Science, PMB No. 3 Townsville MC, Townsville 4810, Queensland, Australia
- Institute of Pharmaceutical Science, King’s College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, United Kingdom
| | - Antonio Starcevic
- Section for Bioinformatics, Department of Biochemical Engineering, Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia
| | - Damir Baranasic
- Section for Bioinformatics, Department of Biochemical Engineering, Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia
| | - Janko Diminic
- Section for Bioinformatics, Department of Biochemical Engineering, Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia
| | - Jurica Zucko
- Section for Bioinformatics, Department of Biochemical Engineering, Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia
| | - Ranko Gacesa
- Section for Bioinformatics, Department of Biochemical Engineering, Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia
| | - Madeleine JH van Oppen
- Centre for Marine Microbiology and Genetics, Australian Institute of Marine Science, PMB No. 3 Townsville MC, Townsville 4810, Queensland, Australia
| | - Daslav Hranueli
- Section for Bioinformatics, Department of Biochemical Engineering, Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia
| | - John Cullum
- Department of Genetics, University of Kaiserslautern, Postfach 3049, 67653 Kaiserslautern, Germany
| | - Paul F Long
- Institute of Pharmaceutical Science, King’s College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, United Kingdom
- Department of Chemistry King’s College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, United Kingdom
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Meyer E, Weis VM. Study of cnidarian-algal symbiosis in the "omics" age. THE BIOLOGICAL BULLETIN 2012; 223:44-65. [PMID: 22983032 DOI: 10.1086/bblv223n1p44] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The symbiotic associations between cnidarians and dinoflagellate algae (Symbiodinium) support productive and diverse ecosystems in coral reefs. Many aspects of this association, including the mechanistic basis of host-symbiont recognition and metabolic interaction, remain poorly understood. The first completed genome sequence for a symbiotic anthozoan is now available (the coral Acropora digitifera), and extensive expressed sequence tag resources are available for a variety of other symbiotic corals and anemones. These resources make it possible to profile gene expression, protein abundance, and protein localization associated with the symbiotic state. Here we review the history of "omics" studies of cnidarian-algal symbiosis and the current availability of sequence resources for corals and anemones, identifying genes putatively involved in symbiosis across 10 anthozoan species. The public availability of candidate symbiosis-associated genes leaves the field of cnidarian-algal symbiosis poised for in-depth comparative studies of sequence diversity and gene expression and for targeted functional studies of genes associated with symbiosis. Reviewing the progress to date suggests directions for future investigations of cnidarian-algal symbiosis that include (i) sequencing of Symbiodinium, (ii) proteomic analysis of the symbiosome membrane complex, (iii) glycomic analysis of Symbiodinium cell surfaces, and (iv) expression profiling of the gastrodermal cells hosting Symbiodinium.
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Affiliation(s)
- Eli Meyer
- Department of Zoology, Oregon State University, Corvallis, Oregon 97331, USA.
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Mydlarz LD, McGinty ES, Harvell CD. What are the physiological and immunological responses of coral to climate warming and disease? J Exp Biol 2010; 213:934-45. [DOI: 10.1242/jeb.037580] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
SUMMARY
Coral mortality due to climate-associated stress is likely to increase as the oceans get warmer and more acidic. Coral bleaching and an increase in infectious disease are linked to above average sea surface temperatures. Despite the uncertain future for corals, recent studies have revealed physiological mechanisms that improve coral resilience to the effects of climate change. Some taxa of bleached corals can increase heterotrophic food intake and exchange symbionts for more thermally tolerant clades; this plasticity can increase the probability of surviving lethal thermal stress. Corals can fight invading pathogens with a suite of innate immune responses that slow and even arrest pathogen growth and reduce further tissue damage. Several of these responses, such as the melanin cascade, circulating amoebocytes and antioxidants, are induced in coral hosts during pathogen invasion or disease. Some components of immunity show thermal resilience and are enhanced during temperature stress and even in bleached corals. These examples suggest some plasticity and resilience to cope with environmental change and even the potential for evolution of resistance to disease. However, there is huge variability in responses among coral species, and the rate of climate change is projected to be so rapid that only extremely hardy taxa are likely to survive the projected changes in climate stressors.
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Affiliation(s)
- Laura D. Mydlarz
- Department of Biology, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Elizabeth S. McGinty
- Department of Biology, University of Texas at Arlington, Arlington, TX 76019, USA
| | - C. Drew Harvell
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14850, USA
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