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Oulhen N, Byrne M, Duffin P, Gomez-Chiarri M, Hewson I, Hodin J, Konar B, Lipp EK, Miner BG, Newton AL, Schiebelhut LM, Smolowitz R, Wahltinez SJ, Wessel GM, Work TM, Zaki HA, Wares JP. A Review of Asteroid Biology in the Context of Sea Star Wasting: Possible Causes and Consequences. THE BIOLOGICAL BULLETIN 2022; 243:50-75. [PMID: 36108034 PMCID: PMC10642522 DOI: 10.1086/719928] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
AbstractSea star wasting-marked in a variety of sea star species as varying degrees of skin lesions followed by disintegration-recently caused one of the largest marine die-offs ever recorded on the west coast of North America, killing billions of sea stars. Despite the important ramifications this mortality had for coastal benthic ecosystems, such as increased abundance of prey, little is known about the causes of the disease or the mechanisms of its progression. Although there have been studies indicating a range of causal mechanisms, including viruses and environmental effects, the broad spatial and depth range of affected populations leaves many questions remaining about either infectious or non-infectious mechanisms. Wasting appears to start with degradation of mutable connective tissue in the body wall, leading to disintegration of the epidermis. Here, we briefly review basic sea star biology in the context of sea star wasting and present our current knowledge and hypotheses related to the symptoms, the microbiome, the viruses, and the associated environmental stressors. We also highlight throughout the article knowledge gaps and the data needed to better understand sea star wasting mechanistically, its causes, and potential management.
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Affiliation(s)
- Nathalie Oulhen
- Department of Molecular and Cell Biology and Biochemistry, Brown University, Providence, Rhode Island
| | - Maria Byrne
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - Paige Duffin
- Department of Genetics, University of Georgia, Athens, Georgia
| | - Marta Gomez-Chiarri
- Department of Fisheries, Animal, and Veterinary Science, University of Rhode Island, Kingston, Rhode Island
| | - Ian Hewson
- Department of Microbiology, Cornell University, Ithaca, New York
| | - Jason Hodin
- Friday Harbor Labs, University of Washington, Friday Harbor, Washington
| | - Brenda Konar
- College of Fisheries and Ocean Sciences, University of Alaska, Fairbanks, Alaska
| | - Erin K. Lipp
- Department of Environmental Health Science, University of Georgia, Athens, Georgia
| | - Benjamin G. Miner
- Department of Biology, Western Washington University, Bellingham, Washington
| | | | - Lauren M. Schiebelhut
- Department of Life and Environmental Sciences, University of California, Merced, California
| | - Roxanna Smolowitz
- Department of Biology and Marine Biology, Roger Williams University, Bristol, Rhode Island
| | - Sarah J. Wahltinez
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, Florida
| | - Gary M. Wessel
- Department of Molecular and Cell Biology and Biochemistry, Brown University, Providence, Rhode Island
| | - Thierry M. Work
- US Geological Survey, National Wildlife Health Center, Honolulu Field Station, Honolulu, Hawaii
| | - Hossam A. Zaki
- Department of Molecular and Cell Biology and Biochemistry, Brown University, Providence, Rhode Island
| | - John P. Wares
- Department of Genetics, University of Georgia, Athens, Georgia
- Odum School of Ecology, University of Georgia, Athens, Georgia
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Crown-of-Thorns Sea Star Acanthaster cf. solaris Has Tissue-Characteristic Microbiomes with Potential Roles in Health and Reproduction. Appl Environ Microbiol 2018; 84:AEM.00181-18. [PMID: 29728381 PMCID: PMC6007096 DOI: 10.1128/aem.00181-18] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 04/20/2018] [Indexed: 11/20/2022] Open
Abstract
Outbreaks of coral-eating crown-of-thorns sea stars (CoTS; Acanthaster species complex) cause substantial coral loss; hence, there is considerable interest in developing prevention and control strategies. We characterized the microbiome of captive CoTS and assessed whether dysbiosis was evident in sea stars during a disease event. Most tissue types had a distinct microbiome. The exception was female gonads, in which the microbiomes were highly variable among individuals. Male gonads were dominated (>97% of reads) by a single Mollicutes-related operational taxonomic unit (OTU). Detailed phylogenetic and microscopy analysis demonstrated the presence of a novel Spiroplasma-related bacterium in the spermatogenic layer. Body wall samples had high relative abundance (43 to 64% of reads) of spirochetes, likely corresponding to subcuticular symbionts reported from many echinoderms. Tube feet were characterized by Hyphomonadaceae (24 to 55% of reads). Pyloric cecal microbiomes had high alpha diversity, comprising many taxa commonly found in gastrointestinal systems. The order Oceanospirillales (genera Endozoicomonas and Kistimonas) was detected in all tissues. A microbiome shift occurred in diseased individuals although differences between tissue types were retained. The relative abundance of spirochetes was significantly reduced in diseased individuals. Kistimonas was present in all diseased individuals and significantly associated with diseased tube feet, but its role in disease causation is unknown. While Arcobacter was significantly associated with diseased tissues and Vibrionaceae increased in diversity, no single OTU was detected in all diseased individuals, suggesting opportunistic proliferation of these taxa in this case. This study shows that CoTS have tissue-characteristic bacterial communities and identifies taxa that could play a role in reproduction and host health. IMPORTANCE Coral-eating crown-of-thorns sea stars (CoTS; Acanthaster species complex) are native to the Indo-Pacific, but during periodic population outbreaks they can reach extreme densities (>1,000 starfish per hectare) and function as a pest species. On the Great Barrier Reef, Australia, CoTS have long been considered one of the major contributors to coral loss. There has been significant investment in a targeted control program using lethal injection, and there is interest in developing additional and complementary technologies that can increase culling efficiencies. The biology of CoTS has been studied extensively, but little is known about their associated microbiome. This cultivation-independent analysis of the CoTS microbiome provides a baseline for future analyses targeting the functional role of symbionts, the identification of pathogens, or the development of reproduction manipulators.
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